1/*
   2 * Copyright © 2014 Red Hat
   3 *
   4 * Permission to use, copy, modify, distribute, and sell this software and its
   5 * documentation for any purpose is hereby granted without fee, provided that
   6 * the above copyright notice appear in all copies and that both that copyright
   7 * notice and this permission notice appear in supporting documentation, and
   8 * that the name of the copyright holders not be used in advertising or
   9 * publicity pertaining to distribution of the software without specific,
  10 * written prior permission.  The copyright holders make no representations
  11 * about the suitability of this software for any purpose.  It is provided "as
  12 * is" without express or implied warranty.
  13 *
  14 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  15 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  16 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  17 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
  18 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  19 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  20 * OF THIS SOFTWARE.
  21 */
  22
  23#include <linux/bitfield.h>
  24#include <linux/delay.h>
  25#include <linux/errno.h>
  26#include <linux/i2c.h>
  27#include <linux/init.h>
  28#include <linux/kernel.h>
  29#include <linux/random.h>
  30#include <linux/sched.h>
  31#include <linux/seq_file.h>
  32#include <linux/iopoll.h>
  33
  34#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
  35#include <linux/stacktrace.h>
  36#include <linux/sort.h>
  37#include <linux/timekeeping.h>
  38#include <linux/math64.h>
  39#endif
  40
  41#include <drm/display/drm_dp_mst_helper.h>
  42#include <drm/drm_atomic.h>
  43#include <drm/drm_atomic_helper.h>
  44#include <drm/drm_drv.h>
  45#include <drm/drm_edid.h>
  46#include <drm/drm_fixed.h>
  47#include <drm/drm_print.h>
  48#include <drm/drm_probe_helper.h>
  49
  50#include "drm_dp_helper_internal.h"
  51#include "drm_dp_mst_topology_internal.h"
  52
  53/**
  54 * DOC: dp mst helper
  55 *
  56 * These functions contain parts of the DisplayPort 1.2a MultiStream Transport
  57 * protocol. The helpers contain a topology manager and bandwidth manager.
  58 * The helpers encapsulate the sending and received of sideband msgs.
  59 */
  60struct drm_dp_pending_up_req {
  61	struct drm_dp_sideband_msg_hdr hdr;
  62	struct drm_dp_sideband_msg_req_body msg;
  63	struct list_head next;
  64};
  65
  66static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
  67				  char *buf);
  68
  69static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port);
  70
  71static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
  72				     int id, u8 start_slot, u8 num_slots);
  73
  74static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
  75				 struct drm_dp_mst_port *port,
  76				 int offset, int size, u8 *bytes);
  77static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
  78				  struct drm_dp_mst_port *port,
  79				  int offset, int size, u8 *bytes);
  80
  81static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
  82				    struct drm_dp_mst_branch *mstb);
  83
  84static void
  85drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
  86				   struct drm_dp_mst_branch *mstb);
  87
  88static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
  89					   struct drm_dp_mst_branch *mstb,
  90					   struct drm_dp_mst_port *port);
  91static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
  92				 u8 *guid);
  93
  94static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
  95static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
  96static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
  97
  98static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
  99						 struct drm_dp_mst_branch *branch);
 100
 101#define DBG_PREFIX "[dp_mst]"
 102
 103#define DP_STR(x) [DP_ ## x] = #x
 104
 105static const char *drm_dp_mst_req_type_str(u8 req_type)
 106{
 107	static const char * const req_type_str[] = {
 108		DP_STR(GET_MSG_TRANSACTION_VERSION),
 109		DP_STR(LINK_ADDRESS),
 110		DP_STR(CONNECTION_STATUS_NOTIFY),
 111		DP_STR(ENUM_PATH_RESOURCES),
 112		DP_STR(ALLOCATE_PAYLOAD),
 113		DP_STR(QUERY_PAYLOAD),
 114		DP_STR(RESOURCE_STATUS_NOTIFY),
 115		DP_STR(CLEAR_PAYLOAD_ID_TABLE),
 116		DP_STR(REMOTE_DPCD_READ),
 117		DP_STR(REMOTE_DPCD_WRITE),
 118		DP_STR(REMOTE_I2C_READ),
 119		DP_STR(REMOTE_I2C_WRITE),
 120		DP_STR(POWER_UP_PHY),
 121		DP_STR(POWER_DOWN_PHY),
 122		DP_STR(SINK_EVENT_NOTIFY),
 123		DP_STR(QUERY_STREAM_ENC_STATUS),
 124	};
 125
 126	if (req_type >= ARRAY_SIZE(req_type_str) ||
 127	    !req_type_str[req_type])
 128		return "unknown";
 129
 130	return req_type_str[req_type];
 131}
 132
 133#undef DP_STR
 134#define DP_STR(x) [DP_NAK_ ## x] = #x
 135
 136static const char *drm_dp_mst_nak_reason_str(u8 nak_reason)
 137{
 138	static const char * const nak_reason_str[] = {
 139		DP_STR(WRITE_FAILURE),
 140		DP_STR(INVALID_READ),
 141		DP_STR(CRC_FAILURE),
 142		DP_STR(BAD_PARAM),
 143		DP_STR(DEFER),
 144		DP_STR(LINK_FAILURE),
 145		DP_STR(NO_RESOURCES),
 146		DP_STR(DPCD_FAIL),
 147		DP_STR(I2C_NAK),
 148		DP_STR(ALLOCATE_FAIL),
 149	};
 150
 151	if (nak_reason >= ARRAY_SIZE(nak_reason_str) ||
 152	    !nak_reason_str[nak_reason])
 153		return "unknown";
 154
 155	return nak_reason_str[nak_reason];
 156}
 157
 158#undef DP_STR
 159#define DP_STR(x) [DRM_DP_SIDEBAND_TX_ ## x] = #x
 160
 161static const char *drm_dp_mst_sideband_tx_state_str(int state)
 162{
 163	static const char * const sideband_reason_str[] = {
 164		DP_STR(QUEUED),
 165		DP_STR(START_SEND),
 166		DP_STR(SENT),
 167		DP_STR(RX),
 168		DP_STR(TIMEOUT),
 169	};
 170
 171	if (state >= ARRAY_SIZE(sideband_reason_str) ||
 172	    !sideband_reason_str[state])
 173		return "unknown";
 174
 175	return sideband_reason_str[state];
 176}
 177
 178static int
 179drm_dp_mst_rad_to_str(const u8 rad[8], u8 lct, char *out, size_t len)
 180{
 181	int i;
 182	u8 unpacked_rad[16];
 183
 184	for (i = 0; i < lct; i++) {
 185		if (i % 2)
 186			unpacked_rad[i] = rad[i / 2] >> 4;
 187		else
 188			unpacked_rad[i] = rad[i / 2] & BIT_MASK(4);
 189	}
 190
 191	/* TODO: Eventually add something to printk so we can format the rad
 192	 * like this: 1.2.3
 193	 */
 194	return snprintf(out, len, "%*phC", lct, unpacked_rad);
 195}
 196
 197/* sideband msg handling */
 198static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
 199{
 200	u8 bitmask = 0x80;
 201	u8 bitshift = 7;
 202	u8 array_index = 0;
 203	int number_of_bits = num_nibbles * 4;
 204	u8 remainder = 0;
 205
 206	while (number_of_bits != 0) {
 207		number_of_bits--;
 208		remainder <<= 1;
 209		remainder |= (data[array_index] & bitmask) >> bitshift;
 210		bitmask >>= 1;
 211		bitshift--;
 212		if (bitmask == 0) {
 213			bitmask = 0x80;
 214			bitshift = 7;
 215			array_index++;
 216		}
 217		if ((remainder & 0x10) == 0x10)
 218			remainder ^= 0x13;
 219	}
 220
 221	number_of_bits = 4;
 222	while (number_of_bits != 0) {
 223		number_of_bits--;
 224		remainder <<= 1;
 225		if ((remainder & 0x10) != 0)
 226			remainder ^= 0x13;
 227	}
 228
 229	return remainder;
 230}
 231
 232static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes)
 233{
 234	u8 bitmask = 0x80;
 235	u8 bitshift = 7;
 236	u8 array_index = 0;
 237	int number_of_bits = number_of_bytes * 8;
 238	u16 remainder = 0;
 239
 240	while (number_of_bits != 0) {
 241		number_of_bits--;
 242		remainder <<= 1;
 243		remainder |= (data[array_index] & bitmask) >> bitshift;
 244		bitmask >>= 1;
 245		bitshift--;
 246		if (bitmask == 0) {
 247			bitmask = 0x80;
 248			bitshift = 7;
 249			array_index++;
 250		}
 251		if ((remainder & 0x100) == 0x100)
 252			remainder ^= 0xd5;
 253	}
 254
 255	number_of_bits = 8;
 256	while (number_of_bits != 0) {
 257		number_of_bits--;
 258		remainder <<= 1;
 259		if ((remainder & 0x100) != 0)
 260			remainder ^= 0xd5;
 261	}
 262
 263	return remainder & 0xff;
 264}
 265static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr)
 266{
 267	u8 size = 3;
 268
 269	size += (hdr->lct / 2);
 270	return size;
 271}
 272
 273static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
 274					   u8 *buf, int *len)
 275{
 276	int idx = 0;
 277	int i;
 278	u8 crc4;
 279
 280	buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
 281	for (i = 0; i < (hdr->lct / 2); i++)
 282		buf[idx++] = hdr->rad[i];
 283	buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
 284		(hdr->msg_len & 0x3f);
 285	buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
 286
 287	crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
 288	buf[idx - 1] |= (crc4 & 0xf);
 289
 290	*len = idx;
 291}
 292
 293static bool drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr *mgr,
 294					   struct drm_dp_sideband_msg_hdr *hdr,
 295					   u8 *buf, int buflen, u8 *hdrlen)
 296{
 297	u8 crc4;
 298	u8 len;
 299	int i;
 300	u8 idx;
 301
 302	if (buf[0] == 0)
 303		return false;
 304	len = 3;
 305	len += ((buf[0] & 0xf0) >> 4) / 2;
 306	if (len > buflen)
 307		return false;
 308	crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
 309
 310	if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
 311		drm_dbg_kms(mgr->dev, "crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
 312		return false;
 313	}
 314
 315	hdr->lct = (buf[0] & 0xf0) >> 4;
 316	hdr->lcr = (buf[0] & 0xf);
 317	idx = 1;
 318	for (i = 0; i < (hdr->lct / 2); i++)
 319		hdr->rad[i] = buf[idx++];
 320	hdr->broadcast = (buf[idx] >> 7) & 0x1;
 321	hdr->path_msg = (buf[idx] >> 6) & 0x1;
 322	hdr->msg_len = buf[idx] & 0x3f;
 323	idx++;
 324	hdr->somt = (buf[idx] >> 7) & 0x1;
 325	hdr->eomt = (buf[idx] >> 6) & 0x1;
 326	hdr->seqno = (buf[idx] >> 4) & 0x1;
 327	idx++;
 328	*hdrlen = idx;
 329	return true;
 330}
 331
 332void
 333drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body *req,
 334			   struct drm_dp_sideband_msg_tx *raw)
 335{
 336	int idx = 0;
 337	int i;
 338	u8 *buf = raw->msg;
 339
 340	buf[idx++] = req->req_type & 0x7f;
 341
 342	switch (req->req_type) {
 343	case DP_ENUM_PATH_RESOURCES:
 344	case DP_POWER_DOWN_PHY:
 345	case DP_POWER_UP_PHY:
 346		buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
 347		idx++;
 348		break;
 349	case DP_ALLOCATE_PAYLOAD:
 350		buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
 351			(req->u.allocate_payload.number_sdp_streams & 0xf);
 352		idx++;
 353		buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
 354		idx++;
 355		buf[idx] = (req->u.allocate_payload.pbn >> 8);
 356		idx++;
 357		buf[idx] = (req->u.allocate_payload.pbn & 0xff);
 358		idx++;
 359		for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
 360			buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) |
 361				(req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
 362			idx++;
 363		}
 364		if (req->u.allocate_payload.number_sdp_streams & 1) {
 365			i = req->u.allocate_payload.number_sdp_streams - 1;
 366			buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
 367			idx++;
 368		}
 369		break;
 370	case DP_QUERY_PAYLOAD:
 371		buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
 372		idx++;
 373		buf[idx] = (req->u.query_payload.vcpi & 0x7f);
 374		idx++;
 375		break;
 376	case DP_REMOTE_DPCD_READ:
 377		buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
 378		buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
 379		idx++;
 380		buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
 381		idx++;
 382		buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
 383		idx++;
 384		buf[idx] = (req->u.dpcd_read.num_bytes);
 385		idx++;
 386		break;
 387
 388	case DP_REMOTE_DPCD_WRITE:
 389		buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
 390		buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
 391		idx++;
 392		buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
 393		idx++;
 394		buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
 395		idx++;
 396		buf[idx] = (req->u.dpcd_write.num_bytes);
 397		idx++;
 398		memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
 399		idx += req->u.dpcd_write.num_bytes;
 400		break;
 401	case DP_REMOTE_I2C_READ:
 402		buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
 403		buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
 404		idx++;
 405		for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
 406			buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
 407			idx++;
 408			buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
 409			idx++;
 410			memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes);
 411			idx += req->u.i2c_read.transactions[i].num_bytes;
 412
 413			buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 4;
 414			buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf);
 415			idx++;
 416		}
 417		buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
 418		idx++;
 419		buf[idx] = (req->u.i2c_read.num_bytes_read);
 420		idx++;
 421		break;
 422
 423	case DP_REMOTE_I2C_WRITE:
 424		buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
 425		idx++;
 426		buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
 427		idx++;
 428		buf[idx] = (req->u.i2c_write.num_bytes);
 429		idx++;
 430		memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
 431		idx += req->u.i2c_write.num_bytes;
 432		break;
 433	case DP_QUERY_STREAM_ENC_STATUS: {
 434		const struct drm_dp_query_stream_enc_status *msg;
 435
 436		msg = &req->u.enc_status;
 437		buf[idx] = msg->stream_id;
 438		idx++;
 439		memcpy(&buf[idx], msg->client_id, sizeof(msg->client_id));
 440		idx += sizeof(msg->client_id);
 441		buf[idx] = 0;
 442		buf[idx] |= FIELD_PREP(GENMASK(1, 0), msg->stream_event);
 443		buf[idx] |= msg->valid_stream_event ? BIT(2) : 0;
 444		buf[idx] |= FIELD_PREP(GENMASK(4, 3), msg->stream_behavior);
 445		buf[idx] |= msg->valid_stream_behavior ? BIT(5) : 0;
 446		idx++;
 447		}
 448		break;
 449	}
 450	raw->cur_len = idx;
 451}
 452EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_encode_sideband_req);
 453
 454/* Decode a sideband request we've encoded, mainly used for debugging */
 455int
 456drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx *raw,
 457			   struct drm_dp_sideband_msg_req_body *req)
 458{
 459	const u8 *buf = raw->msg;
 460	int i, idx = 0;
 461
 462	req->req_type = buf[idx++] & 0x7f;
 463	switch (req->req_type) {
 464	case DP_ENUM_PATH_RESOURCES:
 465	case DP_POWER_DOWN_PHY:
 466	case DP_POWER_UP_PHY:
 467		req->u.port_num.port_number = (buf[idx] >> 4) & 0xf;
 468		break;
 469	case DP_ALLOCATE_PAYLOAD:
 470		{
 471			struct drm_dp_allocate_payload *a =
 472				&req->u.allocate_payload;
 473
 474			a->number_sdp_streams = buf[idx] & 0xf;
 475			a->port_number = (buf[idx] >> 4) & 0xf;
 476
 477			WARN_ON(buf[++idx] & 0x80);
 478			a->vcpi = buf[idx] & 0x7f;
 479
 480			a->pbn = buf[++idx] << 8;
 481			a->pbn |= buf[++idx];
 482
 483			idx++;
 484			for (i = 0; i < a->number_sdp_streams; i++) {
 485				a->sdp_stream_sink[i] =
 486					(buf[idx + (i / 2)] >> ((i % 2) ? 0 : 4)) & 0xf;
 487			}
 488		}
 489		break;
 490	case DP_QUERY_PAYLOAD:
 491		req->u.query_payload.port_number = (buf[idx] >> 4) & 0xf;
 492		WARN_ON(buf[++idx] & 0x80);
 493		req->u.query_payload.vcpi = buf[idx] & 0x7f;
 494		break;
 495	case DP_REMOTE_DPCD_READ:
 496		{
 497			struct drm_dp_remote_dpcd_read *r = &req->u.dpcd_read;
 498
 499			r->port_number = (buf[idx] >> 4) & 0xf;
 500
 501			r->dpcd_address = (buf[idx] << 16) & 0xf0000;
 502			r->dpcd_address |= (buf[++idx] << 8) & 0xff00;
 503			r->dpcd_address |= buf[++idx] & 0xff;
 504
 505			r->num_bytes = buf[++idx];
 506		}
 507		break;
 508	case DP_REMOTE_DPCD_WRITE:
 509		{
 510			struct drm_dp_remote_dpcd_write *w =
 511				&req->u.dpcd_write;
 512
 513			w->port_number = (buf[idx] >> 4) & 0xf;
 514
 515			w->dpcd_address = (buf[idx] << 16) & 0xf0000;
 516			w->dpcd_address |= (buf[++idx] << 8) & 0xff00;
 517			w->dpcd_address |= buf[++idx] & 0xff;
 518
 519			w->num_bytes = buf[++idx];
 520
 521			w->bytes = kmemdup(&buf[++idx], w->num_bytes,
 522					   GFP_KERNEL);
 523			if (!w->bytes)
 524				return -ENOMEM;
 525		}
 526		break;
 527	case DP_REMOTE_I2C_READ:
 528		{
 529			struct drm_dp_remote_i2c_read *r = &req->u.i2c_read;
 530			struct drm_dp_remote_i2c_read_tx *tx;
 531			bool failed = false;
 532
 533			r->num_transactions = buf[idx] & 0x3;
 534			r->port_number = (buf[idx] >> 4) & 0xf;
 535			for (i = 0; i < r->num_transactions; i++) {
 536				tx = &r->transactions[i];
 537
 538				tx->i2c_dev_id = buf[++idx] & 0x7f;
 539				tx->num_bytes = buf[++idx];
 540				tx->bytes = kmemdup(&buf[++idx],
 541						    tx->num_bytes,
 542						    GFP_KERNEL);
 543				if (!tx->bytes) {
 544					failed = true;
 545					break;
 546				}
 547				idx += tx->num_bytes;
 548				tx->no_stop_bit = (buf[idx] >> 5) & 0x1;
 549				tx->i2c_transaction_delay = buf[idx] & 0xf;
 550			}
 551
 552			if (failed) {
 553				for (i = 0; i < r->num_transactions; i++) {
 554					tx = &r->transactions[i];
 555					kfree(tx->bytes);
 556				}
 557				return -ENOMEM;
 558			}
 559
 560			r->read_i2c_device_id = buf[++idx] & 0x7f;
 561			r->num_bytes_read = buf[++idx];
 562		}
 563		break;
 564	case DP_REMOTE_I2C_WRITE:
 565		{
 566			struct drm_dp_remote_i2c_write *w = &req->u.i2c_write;
 567
 568			w->port_number = (buf[idx] >> 4) & 0xf;
 569			w->write_i2c_device_id = buf[++idx] & 0x7f;
 570			w->num_bytes = buf[++idx];
 571			w->bytes = kmemdup(&buf[++idx], w->num_bytes,
 572					   GFP_KERNEL);
 573			if (!w->bytes)
 574				return -ENOMEM;
 575		}
 576		break;
 577	case DP_QUERY_STREAM_ENC_STATUS:
 578		req->u.enc_status.stream_id = buf[idx++];
 579		for (i = 0; i < sizeof(req->u.enc_status.client_id); i++)
 580			req->u.enc_status.client_id[i] = buf[idx++];
 581
 582		req->u.enc_status.stream_event = FIELD_GET(GENMASK(1, 0),
 583							   buf[idx]);
 584		req->u.enc_status.valid_stream_event = FIELD_GET(BIT(2),
 585								 buf[idx]);
 586		req->u.enc_status.stream_behavior = FIELD_GET(GENMASK(4, 3),
 587							      buf[idx]);
 588		req->u.enc_status.valid_stream_behavior = FIELD_GET(BIT(5),
 589								    buf[idx]);
 590		break;
 591	}
 592
 593	return 0;
 594}
 595EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_decode_sideband_req);
 596
 597void
 598drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req,
 599				  int indent, struct drm_printer *printer)
 600{
 601	int i;
 602
 603#define P(f, ...) drm_printf_indent(printer, indent, f, ##__VA_ARGS__)
 604	if (req->req_type == DP_LINK_ADDRESS) {
 605		/* No contents to print */
 606		P("type=%s\n", drm_dp_mst_req_type_str(req->req_type));
 607		return;
 608	}
 609
 610	P("type=%s contents:\n", drm_dp_mst_req_type_str(req->req_type));
 611	indent++;
 612
 613	switch (req->req_type) {
 614	case DP_ENUM_PATH_RESOURCES:
 615	case DP_POWER_DOWN_PHY:
 616	case DP_POWER_UP_PHY:
 617		P("port=%d\n", req->u.port_num.port_number);
 618		break;
 619	case DP_ALLOCATE_PAYLOAD:
 620		P("port=%d vcpi=%d pbn=%d sdp_streams=%d %*ph\n",
 621		  req->u.allocate_payload.port_number,
 622		  req->u.allocate_payload.vcpi, req->u.allocate_payload.pbn,
 623		  req->u.allocate_payload.number_sdp_streams,
 624		  req->u.allocate_payload.number_sdp_streams,
 625		  req->u.allocate_payload.sdp_stream_sink);
 626		break;
 627	case DP_QUERY_PAYLOAD:
 628		P("port=%d vcpi=%d\n",
 629		  req->u.query_payload.port_number,
 630		  req->u.query_payload.vcpi);
 631		break;
 632	case DP_REMOTE_DPCD_READ:
 633		P("port=%d dpcd_addr=%05x len=%d\n",
 634		  req->u.dpcd_read.port_number, req->u.dpcd_read.dpcd_address,
 635		  req->u.dpcd_read.num_bytes);
 636		break;
 637	case DP_REMOTE_DPCD_WRITE:
 638		P("port=%d addr=%05x len=%d: %*ph\n",
 639		  req->u.dpcd_write.port_number,
 640		  req->u.dpcd_write.dpcd_address,
 641		  req->u.dpcd_write.num_bytes, req->u.dpcd_write.num_bytes,
 642		  req->u.dpcd_write.bytes);
 643		break;
 644	case DP_REMOTE_I2C_READ:
 645		P("port=%d num_tx=%d id=%d size=%d:\n",
 646		  req->u.i2c_read.port_number,
 647		  req->u.i2c_read.num_transactions,
 648		  req->u.i2c_read.read_i2c_device_id,
 649		  req->u.i2c_read.num_bytes_read);
 650
 651		indent++;
 652		for (i = 0; i < req->u.i2c_read.num_transactions; i++) {
 653			const struct drm_dp_remote_i2c_read_tx *rtx =
 654				&req->u.i2c_read.transactions[i];
 655
 656			P("%d: id=%03d size=%03d no_stop_bit=%d tx_delay=%03d: %*ph\n",
 657			  i, rtx->i2c_dev_id, rtx->num_bytes,
 658			  rtx->no_stop_bit, rtx->i2c_transaction_delay,
 659			  rtx->num_bytes, rtx->bytes);
 660		}
 661		break;
 662	case DP_REMOTE_I2C_WRITE:
 663		P("port=%d id=%d size=%d: %*ph\n",
 664		  req->u.i2c_write.port_number,
 665		  req->u.i2c_write.write_i2c_device_id,
 666		  req->u.i2c_write.num_bytes, req->u.i2c_write.num_bytes,
 667		  req->u.i2c_write.bytes);
 668		break;
 669	case DP_QUERY_STREAM_ENC_STATUS:
 670		P("stream_id=%u client_id=%*ph stream_event=%x "
 671		  "valid_event=%d stream_behavior=%x valid_behavior=%d",
 672		  req->u.enc_status.stream_id,
 673		  (int)ARRAY_SIZE(req->u.enc_status.client_id),
 674		  req->u.enc_status.client_id, req->u.enc_status.stream_event,
 675		  req->u.enc_status.valid_stream_event,
 676		  req->u.enc_status.stream_behavior,
 677		  req->u.enc_status.valid_stream_behavior);
 678		break;
 679	default:
 680		P("???\n");
 681		break;
 682	}
 683#undef P
 684}
 685EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_dump_sideband_msg_req_body);
 686
 687static inline void
 688drm_dp_mst_dump_sideband_msg_tx(struct drm_printer *p,
 689				const struct drm_dp_sideband_msg_tx *txmsg)
 690{
 691	struct drm_dp_sideband_msg_req_body req;
 692	char buf[64];
 693	int ret;
 694	int i;
 695
 696	drm_dp_mst_rad_to_str(txmsg->dst->rad, txmsg->dst->lct, buf,
 697			      sizeof(buf));
 698	drm_printf(p, "txmsg cur_offset=%x cur_len=%x seqno=%x state=%s path_msg=%d dst=%s\n",
 699		   txmsg->cur_offset, txmsg->cur_len, txmsg->seqno,
 700		   drm_dp_mst_sideband_tx_state_str(txmsg->state),
 701		   txmsg->path_msg, buf);
 702
 703	ret = drm_dp_decode_sideband_req(txmsg, &req);
 704	if (ret) {
 705		drm_printf(p, "<failed to decode sideband req: %d>\n", ret);
 706		return;
 707	}
 708	drm_dp_dump_sideband_msg_req_body(&req, 1, p);
 709
 710	switch (req.req_type) {
 711	case DP_REMOTE_DPCD_WRITE:
 712		kfree(req.u.dpcd_write.bytes);
 713		break;
 714	case DP_REMOTE_I2C_READ:
 715		for (i = 0; i < req.u.i2c_read.num_transactions; i++)
 716			kfree(req.u.i2c_read.transactions[i].bytes);
 717		break;
 718	case DP_REMOTE_I2C_WRITE:
 719		kfree(req.u.i2c_write.bytes);
 720		break;
 721	}
 722}
 723
 724static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
 725{
 726	u8 crc4;
 727
 728	crc4 = drm_dp_msg_data_crc4(msg, len);
 729	msg[len] = crc4;
 730}
 731
 732static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep,
 733					 struct drm_dp_sideband_msg_tx *raw)
 734{
 735	int idx = 0;
 736	u8 *buf = raw->msg;
 737
 738	buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
 739
 740	raw->cur_len = idx;
 741}
 742
 743static int drm_dp_sideband_msg_set_header(struct drm_dp_sideband_msg_rx *msg,
 744					  struct drm_dp_sideband_msg_hdr *hdr,
 745					  u8 hdrlen)
 746{
 747	/*
 748	 * ignore out-of-order messages or messages that are part of a
 749	 * failed transaction
 750	 */
 751	if (!hdr->somt && !msg->have_somt)
 752		return false;
 753
 754	/* get length contained in this portion */
 755	msg->curchunk_idx = 0;
 756	msg->curchunk_len = hdr->msg_len;
 757	msg->curchunk_hdrlen = hdrlen;
 758
 759	/* we have already gotten an somt - don't bother parsing */
 760	if (hdr->somt && msg->have_somt)
 761		return false;
 762
 763	if (hdr->somt) {
 764		memcpy(&msg->initial_hdr, hdr,
 765		       sizeof(struct drm_dp_sideband_msg_hdr));
 766		msg->have_somt = true;
 767	}
 768	if (hdr->eomt)
 769		msg->have_eomt = true;
 770
 771	return true;
 772}
 773
 774/* this adds a chunk of msg to the builder to get the final msg */
 775static bool drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx *msg,
 776					   u8 *replybuf, u8 replybuflen)
 777{
 778	u8 crc4;
 779
 780	memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
 781	msg->curchunk_idx += replybuflen;
 782
 783	if (msg->curchunk_idx >= msg->curchunk_len) {
 784		/* do CRC */
 785		crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
 786		if (crc4 != msg->chunk[msg->curchunk_len - 1])
 787			print_hex_dump(KERN_DEBUG, "wrong crc",
 788				       DUMP_PREFIX_NONE, 16, 1,
 789				       msg->chunk,  msg->curchunk_len, false);
 790		/* copy chunk into bigger msg */
 791		memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
 792		msg->curlen += msg->curchunk_len - 1;
 793	}
 794	return true;
 795}
 796
 797static bool drm_dp_sideband_parse_link_address(const struct drm_dp_mst_topology_mgr *mgr,
 798					       struct drm_dp_sideband_msg_rx *raw,
 799					       struct drm_dp_sideband_msg_reply_body *repmsg)
 800{
 801	int idx = 1;
 802	int i;
 803
 804	memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
 805	idx += 16;
 806	repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
 807	idx++;
 808	if (idx > raw->curlen)
 809		goto fail_len;
 810	for (i = 0; i < repmsg->u.link_addr.nports; i++) {
 811		if (raw->msg[idx] & 0x80)
 812			repmsg->u.link_addr.ports[i].input_port = 1;
 813
 814		repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7;
 815		repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
 816
 817		idx++;
 818		if (idx > raw->curlen)
 819			goto fail_len;
 820		repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
 821		repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
 822		if (repmsg->u.link_addr.ports[i].input_port == 0)
 823			repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
 824		idx++;
 825		if (idx > raw->curlen)
 826			goto fail_len;
 827		if (repmsg->u.link_addr.ports[i].input_port == 0) {
 828			repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
 829			idx++;
 830			if (idx > raw->curlen)
 831				goto fail_len;
 832			memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
 833			idx += 16;
 834			if (idx > raw->curlen)
 835				goto fail_len;
 836			repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf;
 837			repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf);
 838			idx++;
 839
 840		}
 841		if (idx > raw->curlen)
 842			goto fail_len;
 843	}
 844
 845	return true;
 846fail_len:
 847	DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 848	return false;
 849}
 850
 851static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw,
 852						   struct drm_dp_sideband_msg_reply_body *repmsg)
 853{
 854	int idx = 1;
 855
 856	repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
 857	idx++;
 858	if (idx > raw->curlen)
 859		goto fail_len;
 860	repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
 861	idx++;
 862	if (idx > raw->curlen)
 863		goto fail_len;
 864
 865	memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes);
 866	return true;
 867fail_len:
 868	DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 869	return false;
 870}
 871
 872static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw,
 873						      struct drm_dp_sideband_msg_reply_body *repmsg)
 874{
 875	int idx = 1;
 876
 877	repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
 878	idx++;
 879	if (idx > raw->curlen)
 880		goto fail_len;
 881	return true;
 882fail_len:
 883	DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
 884	return false;
 885}
 886
 887static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw,
 888						      struct drm_dp_sideband_msg_reply_body *repmsg)
 889{
 890	int idx = 1;
 891
 892	repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
 893	idx++;
 894	if (idx > raw->curlen)
 895		goto fail_len;
 896	repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
 897	idx++;
 898	/* TODO check */
 899	memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes);
 900	return true;
 901fail_len:
 902	DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen);
 903	return false;
 904}
 905
 906static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw,
 907							  struct drm_dp_sideband_msg_reply_body *repmsg)
 908{
 909	int idx = 1;
 910
 911	repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
 912	repmsg->u.path_resources.fec_capable = raw->msg[idx] & 0x1;
 913	idx++;
 914	if (idx > raw->curlen)
 915		goto fail_len;
 916	repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 917	idx += 2;
 918	if (idx > raw->curlen)
 919		goto fail_len;
 920	repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 921	idx += 2;
 922	if (idx > raw->curlen)
 923		goto fail_len;
 924	return true;
 925fail_len:
 926	DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen);
 927	return false;
 928}
 929
 930static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 931							  struct drm_dp_sideband_msg_reply_body *repmsg)
 932{
 933	int idx = 1;
 934
 935	repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 936	idx++;
 937	if (idx > raw->curlen)
 938		goto fail_len;
 939	repmsg->u.allocate_payload.vcpi = raw->msg[idx];
 940	idx++;
 941	if (idx > raw->curlen)
 942		goto fail_len;
 943	repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 944	idx += 2;
 945	if (idx > raw->curlen)
 946		goto fail_len;
 947	return true;
 948fail_len:
 949	DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen);
 950	return false;
 951}
 952
 953static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 954						    struct drm_dp_sideband_msg_reply_body *repmsg)
 955{
 956	int idx = 1;
 957
 958	repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 959	idx++;
 960	if (idx > raw->curlen)
 961		goto fail_len;
 962	repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
 963	idx += 2;
 964	if (idx > raw->curlen)
 965		goto fail_len;
 966	return true;
 967fail_len:
 968	DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen);
 969	return false;
 970}
 971
 972static bool drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx *raw,
 973						       struct drm_dp_sideband_msg_reply_body *repmsg)
 974{
 975	int idx = 1;
 976
 977	repmsg->u.port_number.port_number = (raw->msg[idx] >> 4) & 0xf;
 978	idx++;
 979	if (idx > raw->curlen) {
 980		DRM_DEBUG_KMS("power up/down phy parse length fail %d %d\n",
 981			      idx, raw->curlen);
 982		return false;
 983	}
 984	return true;
 985}
 986
 987static bool
 988drm_dp_sideband_parse_query_stream_enc_status(
 989				struct drm_dp_sideband_msg_rx *raw,
 990				struct drm_dp_sideband_msg_reply_body *repmsg)
 991{
 992	struct drm_dp_query_stream_enc_status_ack_reply *reply;
 993
 994	reply = &repmsg->u.enc_status;
 995
 996	reply->stream_id = raw->msg[3];
 997
 998	reply->reply_signed = raw->msg[2] & BIT(0);
 999
1000	/*
1001	 * NOTE: It's my impression from reading the spec that the below parsing
1002	 * is correct. However I noticed while testing with an HDCP 1.4 display
1003	 * through an HDCP 2.2 hub that only bit 3 was set. In that case, I
1004	 * would expect both bits to be set. So keep the parsing following the
1005	 * spec, but beware reality might not match the spec (at least for some
1006	 * configurations).
1007	 */
1008	reply->hdcp_1x_device_present = raw->msg[2] & BIT(4);
1009	reply->hdcp_2x_device_present = raw->msg[2] & BIT(3);
1010
1011	reply->query_capable_device_present = raw->msg[2] & BIT(5);
1012	reply->legacy_device_present = raw->msg[2] & BIT(6);
1013	reply->unauthorizable_device_present = raw->msg[2] & BIT(7);
1014
1015	reply->auth_completed = !!(raw->msg[1] & BIT(3));
1016	reply->encryption_enabled = !!(raw->msg[1] & BIT(4));
1017	reply->repeater_present = !!(raw->msg[1] & BIT(5));
1018	reply->state = (raw->msg[1] & GENMASK(7, 6)) >> 6;
1019
1020	return true;
1021}
1022
1023static bool drm_dp_sideband_parse_reply(const struct drm_dp_mst_topology_mgr *mgr,
1024					struct drm_dp_sideband_msg_rx *raw,
1025					struct drm_dp_sideband_msg_reply_body *msg)
1026{
1027	memset(msg, 0, sizeof(*msg));
1028	msg->reply_type = (raw->msg[0] & 0x80) >> 7;
1029	msg->req_type = (raw->msg[0] & 0x7f);
1030
1031	if (msg->reply_type == DP_SIDEBAND_REPLY_NAK) {
1032		memcpy(msg->u.nak.guid, &raw->msg[1], 16);
1033		msg->u.nak.reason = raw->msg[17];
1034		msg->u.nak.nak_data = raw->msg[18];
1035		return false;
1036	}
1037
1038	switch (msg->req_type) {
1039	case DP_LINK_ADDRESS:
1040		return drm_dp_sideband_parse_link_address(mgr, raw, msg);
1041	case DP_QUERY_PAYLOAD:
1042		return drm_dp_sideband_parse_query_payload_ack(raw, msg);
1043	case DP_REMOTE_DPCD_READ:
1044		return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
1045	case DP_REMOTE_DPCD_WRITE:
1046		return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
1047	case DP_REMOTE_I2C_READ:
1048		return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
1049	case DP_REMOTE_I2C_WRITE:
1050		return true; /* since there's nothing to parse */
1051	case DP_ENUM_PATH_RESOURCES:
1052		return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
1053	case DP_ALLOCATE_PAYLOAD:
1054		return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
1055	case DP_POWER_DOWN_PHY:
1056	case DP_POWER_UP_PHY:
1057		return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg);
1058	case DP_CLEAR_PAYLOAD_ID_TABLE:
1059		return true; /* since there's nothing to parse */
1060	case DP_QUERY_STREAM_ENC_STATUS:
1061		return drm_dp_sideband_parse_query_stream_enc_status(raw, msg);
1062	default:
1063		drm_err(mgr->dev, "Got unknown reply 0x%02x (%s)\n",
1064			msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1065		return false;
1066	}
1067}
1068
1069static bool
1070drm_dp_sideband_parse_connection_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1071					       struct drm_dp_sideband_msg_rx *raw,
1072					       struct drm_dp_sideband_msg_req_body *msg)
1073{
1074	int idx = 1;
1075
1076	msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1077	idx++;
1078	if (idx > raw->curlen)
1079		goto fail_len;
1080
1081	memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
1082	idx += 16;
1083	if (idx > raw->curlen)
1084		goto fail_len;
1085
1086	msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
1087	msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
1088	msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
1089	msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
1090	msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
1091	idx++;
1092	return true;
1093fail_len:
1094	drm_dbg_kms(mgr->dev, "connection status reply parse length fail %d %d\n",
1095		    idx, raw->curlen);
1096	return false;
1097}
1098
1099static bool drm_dp_sideband_parse_resource_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1100							 struct drm_dp_sideband_msg_rx *raw,
1101							 struct drm_dp_sideband_msg_req_body *msg)
1102{
1103	int idx = 1;
1104
1105	msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1106	idx++;
1107	if (idx > raw->curlen)
1108		goto fail_len;
1109
1110	memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
1111	idx += 16;
1112	if (idx > raw->curlen)
1113		goto fail_len;
1114
1115	msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
1116	idx++;
1117	return true;
1118fail_len:
1119	drm_dbg_kms(mgr->dev, "resource status reply parse length fail %d %d\n", idx, raw->curlen);
1120	return false;
1121}
1122
1123static bool drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr *mgr,
1124				      struct drm_dp_sideband_msg_rx *raw,
1125				      struct drm_dp_sideband_msg_req_body *msg)
1126{
1127	memset(msg, 0, sizeof(*msg));
1128	msg->req_type = (raw->msg[0] & 0x7f);
1129
1130	switch (msg->req_type) {
1131	case DP_CONNECTION_STATUS_NOTIFY:
1132		return drm_dp_sideband_parse_connection_status_notify(mgr, raw, msg);
1133	case DP_RESOURCE_STATUS_NOTIFY:
1134		return drm_dp_sideband_parse_resource_status_notify(mgr, raw, msg);
1135	default:
1136		drm_err(mgr->dev, "Got unknown request 0x%02x (%s)\n",
1137			msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1138		return false;
1139	}
1140}
1141
1142static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg,
1143			     u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
1144{
1145	struct drm_dp_sideband_msg_req_body req;
1146
1147	req.req_type = DP_REMOTE_DPCD_WRITE;
1148	req.u.dpcd_write.port_number = port_num;
1149	req.u.dpcd_write.dpcd_address = offset;
1150	req.u.dpcd_write.num_bytes = num_bytes;
1151	req.u.dpcd_write.bytes = bytes;
1152	drm_dp_encode_sideband_req(&req, msg);
1153}
1154
1155static void build_link_address(struct drm_dp_sideband_msg_tx *msg)
1156{
1157	struct drm_dp_sideband_msg_req_body req;
1158
1159	req.req_type = DP_LINK_ADDRESS;
1160	drm_dp_encode_sideband_req(&req, msg);
1161}
1162
1163static void build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
1164{
1165	struct drm_dp_sideband_msg_req_body req;
1166
1167	req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE;
1168	drm_dp_encode_sideband_req(&req, msg);
1169	msg->path_msg = true;
1170}
1171
1172static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg,
1173				     int port_num)
1174{
1175	struct drm_dp_sideband_msg_req_body req;
1176
1177	req.req_type = DP_ENUM_PATH_RESOURCES;
1178	req.u.port_num.port_number = port_num;
1179	drm_dp_encode_sideband_req(&req, msg);
1180	msg->path_msg = true;
1181	return 0;
1182}
1183
1184static void build_allocate_payload(struct drm_dp_sideband_msg_tx *msg,
1185				   int port_num,
1186				   u8 vcpi, uint16_t pbn,
1187				   u8 number_sdp_streams,
1188				   u8 *sdp_stream_sink)
1189{
1190	struct drm_dp_sideband_msg_req_body req;
1191
1192	memset(&req, 0, sizeof(req));
1193	req.req_type = DP_ALLOCATE_PAYLOAD;
1194	req.u.allocate_payload.port_number = port_num;
1195	req.u.allocate_payload.vcpi = vcpi;
1196	req.u.allocate_payload.pbn = pbn;
1197	req.u.allocate_payload.number_sdp_streams = number_sdp_streams;
1198	memcpy(req.u.allocate_payload.sdp_stream_sink, sdp_stream_sink,
1199		   number_sdp_streams);
1200	drm_dp_encode_sideband_req(&req, msg);
1201	msg->path_msg = true;
1202}
1203
1204static void build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
1205				   int port_num, bool power_up)
1206{
1207	struct drm_dp_sideband_msg_req_body req;
1208
1209	if (power_up)
1210		req.req_type = DP_POWER_UP_PHY;
1211	else
1212		req.req_type = DP_POWER_DOWN_PHY;
1213
1214	req.u.port_num.port_number = port_num;
1215	drm_dp_encode_sideband_req(&req, msg);
1216	msg->path_msg = true;
1217}
1218
1219static int
1220build_query_stream_enc_status(struct drm_dp_sideband_msg_tx *msg, u8 stream_id,
1221			      u8 *q_id)
1222{
1223	struct drm_dp_sideband_msg_req_body req;
1224
1225	req.req_type = DP_QUERY_STREAM_ENC_STATUS;
1226	req.u.enc_status.stream_id = stream_id;
1227	memcpy(req.u.enc_status.client_id, q_id,
1228	       sizeof(req.u.enc_status.client_id));
1229	req.u.enc_status.stream_event = 0;
1230	req.u.enc_status.valid_stream_event = false;
1231	req.u.enc_status.stream_behavior = 0;
1232	req.u.enc_status.valid_stream_behavior = false;
1233
1234	drm_dp_encode_sideband_req(&req, msg);
1235	return 0;
1236}
1237
1238static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
1239			      struct drm_dp_sideband_msg_tx *txmsg)
1240{
1241	unsigned int state;
1242
1243	/*
1244	 * All updates to txmsg->state are protected by mgr->qlock, and the two
1245	 * cases we check here are terminal states. For those the barriers
1246	 * provided by the wake_up/wait_event pair are enough.
1247	 */
1248	state = READ_ONCE(txmsg->state);
1249	return (state == DRM_DP_SIDEBAND_TX_RX ||
1250		state == DRM_DP_SIDEBAND_TX_TIMEOUT);
1251}
1252
1253static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
1254				    struct drm_dp_sideband_msg_tx *txmsg)
1255{
1256	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1257	unsigned long wait_timeout = msecs_to_jiffies(4000);
1258	unsigned long wait_expires = jiffies + wait_timeout;
1259	int ret;
1260
1261	for (;;) {
1262		/*
1263		 * If the driver provides a way for this, change to
1264		 * poll-waiting for the MST reply interrupt if we didn't receive
1265		 * it for 50 msec. This would cater for cases where the HPD
1266		 * pulse signal got lost somewhere, even though the sink raised
1267		 * the corresponding MST interrupt correctly. One example is the
1268		 * Club 3D CAC-1557 TypeC -> DP adapter which for some reason
1269		 * filters out short pulses with a duration less than ~540 usec.
1270		 *
1271		 * The poll period is 50 msec to avoid missing an interrupt
1272		 * after the sink has cleared it (after a 110msec timeout
1273		 * since it raised the interrupt).
1274		 */
1275		ret = wait_event_timeout(mgr->tx_waitq,
1276					 check_txmsg_state(mgr, txmsg),
1277					 mgr->cbs->poll_hpd_irq ?
1278						msecs_to_jiffies(50) :
1279						wait_timeout);
1280
1281		if (ret || !mgr->cbs->poll_hpd_irq ||
1282		    time_after(jiffies, wait_expires))
1283			break;
1284
1285		mgr->cbs->poll_hpd_irq(mgr);
1286	}
1287
1288	mutex_lock(&mgr->qlock);
1289	if (ret > 0) {
1290		if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
1291			ret = -EIO;
1292			goto out;
1293		}
1294	} else {
1295		drm_dbg_kms(mgr->dev, "timedout msg send %p %d %d\n",
1296			    txmsg, txmsg->state, txmsg->seqno);
1297
1298		/* dump some state */
1299		ret = -EIO;
1300
1301		/* remove from q */
1302		if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
1303		    txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
1304		    txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
1305			list_del(&txmsg->next);
1306	}
1307out:
1308	if (unlikely(ret == -EIO) && drm_debug_enabled(DRM_UT_DP)) {
1309		struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1310
1311		drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
1312	}
1313	mutex_unlock(&mgr->qlock);
1314
1315	drm_dp_mst_kick_tx(mgr);
1316	return ret;
1317}
1318
1319static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
1320{
1321	struct drm_dp_mst_branch *mstb;
1322
1323	mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
1324	if (!mstb)
1325		return NULL;
1326
1327	mstb->lct = lct;
1328	if (lct > 1)
1329		memcpy(mstb->rad, rad, lct / 2);
1330	INIT_LIST_HEAD(&mstb->ports);
1331	kref_init(&mstb->topology_kref);
1332	kref_init(&mstb->malloc_kref);
1333	return mstb;
1334}
1335
1336static void drm_dp_free_mst_branch_device(struct kref *kref)
1337{
1338	struct drm_dp_mst_branch *mstb =
1339		container_of(kref, struct drm_dp_mst_branch, malloc_kref);
1340
1341	if (mstb->port_parent)
1342		drm_dp_mst_put_port_malloc(mstb->port_parent);
1343
1344	kfree(mstb);
1345}
1346
1347/**
1348 * DOC: Branch device and port refcounting
1349 *
1350 * Topology refcount overview
1351 * ~~~~~~~~~~~~~~~~~~~~~~~~~~
1352 *
1353 * The refcounting schemes for &struct drm_dp_mst_branch and &struct
1354 * drm_dp_mst_port are somewhat unusual. Both ports and branch devices have
1355 * two different kinds of refcounts: topology refcounts, and malloc refcounts.
1356 *
1357 * Topology refcounts are not exposed to drivers, and are handled internally
1358 * by the DP MST helpers. The helpers use them in order to prevent the
1359 * in-memory topology state from being changed in the middle of critical
1360 * operations like changing the internal state of payload allocations. This
1361 * means each branch and port will be considered to be connected to the rest
1362 * of the topology until its topology refcount reaches zero. Additionally,
1363 * for ports this means that their associated &struct drm_connector will stay
1364 * registered with userspace until the port's refcount reaches 0.
1365 *
1366 * Malloc refcount overview
1367 * ~~~~~~~~~~~~~~~~~~~~~~~~
1368 *
1369 * Malloc references are used to keep a &struct drm_dp_mst_port or &struct
1370 * drm_dp_mst_branch allocated even after all of its topology references have
1371 * been dropped, so that the driver or MST helpers can safely access each
1372 * branch's last known state before it was disconnected from the topology.
1373 * When the malloc refcount of a port or branch reaches 0, the memory
1374 * allocation containing the &struct drm_dp_mst_branch or &struct
1375 * drm_dp_mst_port respectively will be freed.
1376 *
1377 * For &struct drm_dp_mst_branch, malloc refcounts are not currently exposed
1378 * to drivers. As of writing this documentation, there are no drivers that
1379 * have a usecase for accessing &struct drm_dp_mst_branch outside of the MST
1380 * helpers. Exposing this API to drivers in a race-free manner would take more
1381 * tweaking of the refcounting scheme, however patches are welcome provided
1382 * there is a legitimate driver usecase for this.
1383 *
1384 * Refcount relationships in a topology
1385 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1386 *
1387 * Let's take a look at why the relationship between topology and malloc
1388 * refcounts is designed the way it is.
1389 *
1390 * .. kernel-figure:: dp-mst/topology-figure-1.dot
1391 *
1392 *    An example of topology and malloc refs in a DP MST topology with two
1393 *    active payloads. Topology refcount increments are indicated by solid
1394 *    lines, and malloc refcount increments are indicated by dashed lines.
1395 *    Each starts from the branch which incremented the refcount, and ends at
1396 *    the branch to which the refcount belongs to, i.e. the arrow points the
1397 *    same way as the C pointers used to reference a structure.
1398 *
1399 * As you can see in the above figure, every branch increments the topology
1400 * refcount of its children, and increments the malloc refcount of its
1401 * parent. Additionally, every payload increments the malloc refcount of its
1402 * assigned port by 1.
1403 *
1404 * So, what would happen if MSTB #3 from the above figure was unplugged from
1405 * the system, but the driver hadn't yet removed payload #2 from port #3? The
1406 * topology would start to look like the figure below.
1407 *
1408 * .. kernel-figure:: dp-mst/topology-figure-2.dot
1409 *
1410 *    Ports and branch devices which have been released from memory are
1411 *    colored grey, and references which have been removed are colored red.
1412 *
1413 * Whenever a port or branch device's topology refcount reaches zero, it will
1414 * decrement the topology refcounts of all its children, the malloc refcount
1415 * of its parent, and finally its own malloc refcount. For MSTB #4 and port
1416 * #4, this means they both have been disconnected from the topology and freed
1417 * from memory. But, because payload #2 is still holding a reference to port
1418 * #3, port #3 is removed from the topology but its &struct drm_dp_mst_port
1419 * is still accessible from memory. This also means port #3 has not yet
1420 * decremented the malloc refcount of MSTB #3, so its &struct
1421 * drm_dp_mst_branch will also stay allocated in memory until port #3's
1422 * malloc refcount reaches 0.
1423 *
1424 * This relationship is necessary because in order to release payload #2, we
1425 * need to be able to figure out the last relative of port #3 that's still
1426 * connected to the topology. In this case, we would travel up the topology as
1427 * shown below.
1428 *
1429 * .. kernel-figure:: dp-mst/topology-figure-3.dot
1430 *
1431 * And finally, remove payload #2 by communicating with port #2 through
1432 * sideband transactions.
1433 */
1434
1435/**
1436 * drm_dp_mst_get_mstb_malloc() - Increment the malloc refcount of a branch
1437 * device
1438 * @mstb: The &struct drm_dp_mst_branch to increment the malloc refcount of
1439 *
1440 * Increments &drm_dp_mst_branch.malloc_kref. When
1441 * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1442 * will be released and @mstb may no longer be used.
1443 *
1444 * See also: drm_dp_mst_put_mstb_malloc()
1445 */
1446static void
1447drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch *mstb)
1448{
1449	kref_get(&mstb->malloc_kref);
1450	drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref));
1451}
1452
1453/**
1454 * drm_dp_mst_put_mstb_malloc() - Decrement the malloc refcount of a branch
1455 * device
1456 * @mstb: The &struct drm_dp_mst_branch to decrement the malloc refcount of
1457 *
1458 * Decrements &drm_dp_mst_branch.malloc_kref. When
1459 * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1460 * will be released and @mstb may no longer be used.
1461 *
1462 * See also: drm_dp_mst_get_mstb_malloc()
1463 */
1464static void
1465drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch *mstb)
1466{
1467	drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref) - 1);
1468	kref_put(&mstb->malloc_kref, drm_dp_free_mst_branch_device);
1469}
1470
1471static void drm_dp_free_mst_port(struct kref *kref)
1472{
1473	struct drm_dp_mst_port *port =
1474		container_of(kref, struct drm_dp_mst_port, malloc_kref);
1475
1476	drm_dp_mst_put_mstb_malloc(port->parent);
1477	kfree(port);
1478}
1479
1480/**
1481 * drm_dp_mst_get_port_malloc() - Increment the malloc refcount of an MST port
1482 * @port: The &struct drm_dp_mst_port to increment the malloc refcount of
1483 *
1484 * Increments &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1485 * reaches 0, the memory allocation for @port will be released and @port may
1486 * no longer be used.
1487 *
1488 * Because @port could potentially be freed at any time by the DP MST helpers
1489 * if &drm_dp_mst_port.malloc_kref reaches 0, including during a call to this
1490 * function, drivers that which to make use of &struct drm_dp_mst_port should
1491 * ensure that they grab at least one main malloc reference to their MST ports
1492 * in &drm_dp_mst_topology_cbs.add_connector. This callback is called before
1493 * there is any chance for &drm_dp_mst_port.malloc_kref to reach 0.
1494 *
1495 * See also: drm_dp_mst_put_port_malloc()
1496 */
1497void
1498drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port)
1499{
1500	kref_get(&port->malloc_kref);
1501	drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref));
1502}
1503EXPORT_SYMBOL(drm_dp_mst_get_port_malloc);
1504
1505/**
1506 * drm_dp_mst_put_port_malloc() - Decrement the malloc refcount of an MST port
1507 * @port: The &struct drm_dp_mst_port to decrement the malloc refcount of
1508 *
1509 * Decrements &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1510 * reaches 0, the memory allocation for @port will be released and @port may
1511 * no longer be used.
1512 *
1513 * See also: drm_dp_mst_get_port_malloc()
1514 */
1515void
1516drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port)
1517{
1518	drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref) - 1);
1519	kref_put(&port->malloc_kref, drm_dp_free_mst_port);
1520}
1521EXPORT_SYMBOL(drm_dp_mst_put_port_malloc);
1522
1523#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
1524
1525#define STACK_DEPTH 8
1526
1527static noinline void
1528__topology_ref_save(struct drm_dp_mst_topology_mgr *mgr,
1529		    struct drm_dp_mst_topology_ref_history *history,
1530		    enum drm_dp_mst_topology_ref_type type)
1531{
1532	struct drm_dp_mst_topology_ref_entry *entry = NULL;
1533	depot_stack_handle_t backtrace;
1534	ulong stack_entries[STACK_DEPTH];
1535	uint n;
1536	int i;
1537
1538	n = stack_trace_save(stack_entries, ARRAY_SIZE(stack_entries), 1);
1539	backtrace = stack_depot_save(stack_entries, n, GFP_KERNEL);
1540	if (!backtrace)
1541		return;
1542
1543	/* Try to find an existing entry for this backtrace */
1544	for (i = 0; i < history->len; i++) {
1545		if (history->entries[i].backtrace == backtrace) {
1546			entry = &history->entries[i];
1547			break;
1548		}
1549	}
1550
1551	/* Otherwise add one */
1552	if (!entry) {
1553		struct drm_dp_mst_topology_ref_entry *new;
1554		int new_len = history->len + 1;
1555
1556		new = krealloc(history->entries, sizeof(*new) * new_len,
1557			       GFP_KERNEL);
1558		if (!new)
1559			return;
1560
1561		entry = &new[history->len];
1562		history->len = new_len;
1563		history->entries = new;
1564
1565		entry->backtrace = backtrace;
1566		entry->type = type;
1567		entry->count = 0;
1568	}
1569	entry->count++;
1570	entry->ts_nsec = ktime_get_ns();
1571}
1572
1573static int
1574topology_ref_history_cmp(const void *a, const void *b)
1575{
1576	const struct drm_dp_mst_topology_ref_entry *entry_a = a, *entry_b = b;
1577
1578	if (entry_a->ts_nsec > entry_b->ts_nsec)
1579		return 1;
1580	else if (entry_a->ts_nsec < entry_b->ts_nsec)
1581		return -1;
1582	else
1583		return 0;
1584}
1585
1586static inline const char *
1587topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)
1588{
1589	if (type == DRM_DP_MST_TOPOLOGY_REF_GET)
1590		return "get";
1591	else
1592		return "put";
1593}
1594
1595static void
1596__dump_topology_ref_history(struct drm_dp_mst_topology_ref_history *history,
1597			    void *ptr, const char *type_str)
1598{
1599	struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1600	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
1601	int i;
1602
1603	if (!buf)
1604		return;
1605
1606	if (!history->len)
1607		goto out;
1608
1609	/* First, sort the list so that it goes from oldest to newest
1610	 * reference entry
1611	 */
1612	sort(history->entries, history->len, sizeof(*history->entries),
1613	     topology_ref_history_cmp, NULL);
1614
1615	drm_printf(&p, "%s (%p) topology count reached 0, dumping history:\n",
1616		   type_str, ptr);
1617
1618	for (i = 0; i < history->len; i++) {
1619		const struct drm_dp_mst_topology_ref_entry *entry =
1620			&history->entries[i];
1621		u64 ts_nsec = entry->ts_nsec;
1622		u32 rem_nsec = do_div(ts_nsec, 1000000000);
1623
1624		stack_depot_snprint(entry->backtrace, buf, PAGE_SIZE, 4);
1625
1626		drm_printf(&p, "  %d %ss (last at %5llu.%06u):\n%s",
1627			   entry->count,
1628			   topology_ref_type_to_str(entry->type),
1629			   ts_nsec, rem_nsec / 1000, buf);
1630	}
1631
1632	/* Now free the history, since this is the only time we expose it */
1633	kfree(history->entries);
1634out:
1635	kfree(buf);
1636}
1637
1638static __always_inline void
1639drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb)
1640{
1641	__dump_topology_ref_history(&mstb->topology_ref_history, mstb,
1642				    "MSTB");
1643}
1644
1645static __always_inline void
1646drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port)
1647{
1648	__dump_topology_ref_history(&port->topology_ref_history, port,
1649				    "Port");
1650}
1651
1652static __always_inline void
1653save_mstb_topology_ref(struct drm_dp_mst_branch *mstb,
1654		       enum drm_dp_mst_topology_ref_type type)
1655{
1656	__topology_ref_save(mstb->mgr, &mstb->topology_ref_history, type);
1657}
1658
1659static __always_inline void
1660save_port_topology_ref(struct drm_dp_mst_port *port,
1661		       enum drm_dp_mst_topology_ref_type type)
1662{
1663	__topology_ref_save(port->mgr, &port->topology_ref_history, type);
1664}
1665
1666static inline void
1667topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr)
1668{
1669	mutex_lock(&mgr->topology_ref_history_lock);
1670}
1671
1672static inline void
1673topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr)
1674{
1675	mutex_unlock(&mgr->topology_ref_history_lock);
1676}
1677#else
1678static inline void
1679topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr) {}
1680static inline void
1681topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr) {}
1682static inline void
1683drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb) {}
1684static inline void
1685drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port) {}
1686#define save_mstb_topology_ref(mstb, type)
1687#define save_port_topology_ref(port, type)
1688#endif
1689
1690struct drm_dp_mst_atomic_payload *
1691drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state *state,
1692				 struct drm_dp_mst_port *port)
1693{
1694	struct drm_dp_mst_atomic_payload *payload;
1695
1696	list_for_each_entry(payload, &state->payloads, next)
1697		if (payload->port == port)
1698			return payload;
1699
1700	return NULL;
1701}
1702EXPORT_SYMBOL(drm_atomic_get_mst_payload_state);
1703
1704static void drm_dp_destroy_mst_branch_device(struct kref *kref)
1705{
1706	struct drm_dp_mst_branch *mstb =
1707		container_of(kref, struct drm_dp_mst_branch, topology_kref);
1708	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1709
1710	drm_dp_mst_dump_mstb_topology_history(mstb);
1711
1712	INIT_LIST_HEAD(&mstb->destroy_next);
1713
1714	/*
1715	 * This can get called under mgr->mutex, so we need to perform the
1716	 * actual destruction of the mstb in another worker
1717	 */
1718	mutex_lock(&mgr->delayed_destroy_lock);
1719	list_add(&mstb->destroy_next, &mgr->destroy_branch_device_list);
1720	mutex_unlock(&mgr->delayed_destroy_lock);
1721	queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1722}
1723
1724/**
1725 * drm_dp_mst_topology_try_get_mstb() - Increment the topology refcount of a
1726 * branch device unless it's zero
1727 * @mstb: &struct drm_dp_mst_branch to increment the topology refcount of
1728 *
1729 * Attempts to grab a topology reference to @mstb, if it hasn't yet been
1730 * removed from the topology (e.g. &drm_dp_mst_branch.topology_kref has
1731 * reached 0). Holding a topology reference implies that a malloc reference
1732 * will be held to @mstb as long as the user holds the topology reference.
1733 *
1734 * Care should be taken to ensure that the user has at least one malloc
1735 * reference to @mstb. If you already have a topology reference to @mstb, you
1736 * should use drm_dp_mst_topology_get_mstb() instead.
1737 *
1738 * See also:
1739 * drm_dp_mst_topology_get_mstb()
1740 * drm_dp_mst_topology_put_mstb()
1741 *
1742 * Returns:
1743 * * 1: A topology reference was grabbed successfully
1744 * * 0: @port is no longer in the topology, no reference was grabbed
1745 */
1746static int __must_check
1747drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch *mstb)
1748{
1749	int ret;
1750
1751	topology_ref_history_lock(mstb->mgr);
1752	ret = kref_get_unless_zero(&mstb->topology_kref);
1753	if (ret) {
1754		drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1755		save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1756	}
1757
1758	topology_ref_history_unlock(mstb->mgr);
1759
1760	return ret;
1761}
1762
1763/**
1764 * drm_dp_mst_topology_get_mstb() - Increment the topology refcount of a
1765 * branch device
1766 * @mstb: The &struct drm_dp_mst_branch to increment the topology refcount of
1767 *
1768 * Increments &drm_dp_mst_branch.topology_refcount without checking whether or
1769 * not it's already reached 0. This is only valid to use in scenarios where
1770 * you are already guaranteed to have at least one active topology reference
1771 * to @mstb. Otherwise, drm_dp_mst_topology_try_get_mstb() must be used.
1772 *
1773 * See also:
1774 * drm_dp_mst_topology_try_get_mstb()
1775 * drm_dp_mst_topology_put_mstb()
1776 */
1777static void drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch *mstb)
1778{
1779	topology_ref_history_lock(mstb->mgr);
1780
1781	save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1782	WARN_ON(kref_read(&mstb->topology_kref) == 0);
1783	kref_get(&mstb->topology_kref);
1784	drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1785
1786	topology_ref_history_unlock(mstb->mgr);
1787}
1788
1789/**
1790 * drm_dp_mst_topology_put_mstb() - release a topology reference to a branch
1791 * device
1792 * @mstb: The &struct drm_dp_mst_branch to release the topology reference from
1793 *
1794 * Releases a topology reference from @mstb by decrementing
1795 * &drm_dp_mst_branch.topology_kref.
1796 *
1797 * See also:
1798 * drm_dp_mst_topology_try_get_mstb()
1799 * drm_dp_mst_topology_get_mstb()
1800 */
1801static void
1802drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch *mstb)
1803{
1804	topology_ref_history_lock(mstb->mgr);
1805
1806	drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref) - 1);
1807	save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_PUT);
1808
1809	topology_ref_history_unlock(mstb->mgr);
1810	kref_put(&mstb->topology_kref, drm_dp_destroy_mst_branch_device);
1811}
1812
1813static void drm_dp_destroy_port(struct kref *kref)
1814{
1815	struct drm_dp_mst_port *port =
1816		container_of(kref, struct drm_dp_mst_port, topology_kref);
1817	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
1818
1819	drm_dp_mst_dump_port_topology_history(port);
1820
1821	/* There's nothing that needs locking to destroy an input port yet */
1822	if (port->input) {
1823		drm_dp_mst_put_port_malloc(port);
1824		return;
1825	}
1826
1827	drm_edid_free(port->cached_edid);
1828
1829	/*
1830	 * we can't destroy the connector here, as we might be holding the
1831	 * mode_config.mutex from an EDID retrieval
1832	 */
1833	mutex_lock(&mgr->delayed_destroy_lock);
1834	list_add(&port->next, &mgr->destroy_port_list);
1835	mutex_unlock(&mgr->delayed_destroy_lock);
1836	queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1837}
1838
1839/**
1840 * drm_dp_mst_topology_try_get_port() - Increment the topology refcount of a
1841 * port unless it's zero
1842 * @port: &struct drm_dp_mst_port to increment the topology refcount of
1843 *
1844 * Attempts to grab a topology reference to @port, if it hasn't yet been
1845 * removed from the topology (e.g. &drm_dp_mst_port.topology_kref has reached
1846 * 0). Holding a topology reference implies that a malloc reference will be
1847 * held to @port as long as the user holds the topology reference.
1848 *
1849 * Care should be taken to ensure that the user has at least one malloc
1850 * reference to @port. If you already have a topology reference to @port, you
1851 * should use drm_dp_mst_topology_get_port() instead.
1852 *
1853 * See also:
1854 * drm_dp_mst_topology_get_port()
1855 * drm_dp_mst_topology_put_port()
1856 *
1857 * Returns:
1858 * * 1: A topology reference was grabbed successfully
1859 * * 0: @port is no longer in the topology, no reference was grabbed
1860 */
1861static int __must_check
1862drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port *port)
1863{
1864	int ret;
1865
1866	topology_ref_history_lock(port->mgr);
1867	ret = kref_get_unless_zero(&port->topology_kref);
1868	if (ret) {
1869		drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1870		save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1871	}
1872
1873	topology_ref_history_unlock(port->mgr);
1874	return ret;
1875}
1876
1877/**
1878 * drm_dp_mst_topology_get_port() - Increment the topology refcount of a port
1879 * @port: The &struct drm_dp_mst_port to increment the topology refcount of
1880 *
1881 * Increments &drm_dp_mst_port.topology_refcount without checking whether or
1882 * not it's already reached 0. This is only valid to use in scenarios where
1883 * you are already guaranteed to have at least one active topology reference
1884 * to @port. Otherwise, drm_dp_mst_topology_try_get_port() must be used.
1885 *
1886 * See also:
1887 * drm_dp_mst_topology_try_get_port()
1888 * drm_dp_mst_topology_put_port()
1889 */
1890static void drm_dp_mst_topology_get_port(struct drm_dp_mst_port *port)
1891{
1892	topology_ref_history_lock(port->mgr);
1893
1894	WARN_ON(kref_read(&port->topology_kref) == 0);
1895	kref_get(&port->topology_kref);
1896	drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1897	save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1898
1899	topology_ref_history_unlock(port->mgr);
1900}
1901
1902/**
1903 * drm_dp_mst_topology_put_port() - release a topology reference to a port
1904 * @port: The &struct drm_dp_mst_port to release the topology reference from
1905 *
1906 * Releases a topology reference from @port by decrementing
1907 * &drm_dp_mst_port.topology_kref.
1908 *
1909 * See also:
1910 * drm_dp_mst_topology_try_get_port()
1911 * drm_dp_mst_topology_get_port()
1912 */
1913static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port)
1914{
1915	topology_ref_history_lock(port->mgr);
1916
1917	drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref) - 1);
1918	save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_PUT);
1919
1920	topology_ref_history_unlock(port->mgr);
1921	kref_put(&port->topology_kref, drm_dp_destroy_port);
1922}
1923
1924static struct drm_dp_mst_branch *
1925drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch *mstb,
1926					      struct drm_dp_mst_branch *to_find)
1927{
1928	struct drm_dp_mst_port *port;
1929	struct drm_dp_mst_branch *rmstb;
1930
1931	if (to_find == mstb)
1932		return mstb;
1933
1934	list_for_each_entry(port, &mstb->ports, next) {
1935		if (port->mstb) {
1936			rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1937			    port->mstb, to_find);
1938			if (rmstb)
1939				return rmstb;
1940		}
1941	}
1942	return NULL;
1943}
1944
1945static struct drm_dp_mst_branch *
1946drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr *mgr,
1947				       struct drm_dp_mst_branch *mstb)
1948{
1949	struct drm_dp_mst_branch *rmstb = NULL;
1950
1951	mutex_lock(&mgr->lock);
1952	if (mgr->mst_primary) {
1953		rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1954		    mgr->mst_primary, mstb);
1955
1956		if (rmstb && !drm_dp_mst_topology_try_get_mstb(rmstb))
1957			rmstb = NULL;
1958	}
1959	mutex_unlock(&mgr->lock);
1960	return rmstb;
1961}
1962
1963static struct drm_dp_mst_port *
1964drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch *mstb,
1965					      struct drm_dp_mst_port *to_find)
1966{
1967	struct drm_dp_mst_port *port, *mport;
1968
1969	list_for_each_entry(port, &mstb->ports, next) {
1970		if (port == to_find)
1971			return port;
1972
1973		if (port->mstb) {
1974			mport = drm_dp_mst_topology_get_port_validated_locked(
1975			    port->mstb, to_find);
1976			if (mport)
1977				return mport;
1978		}
1979	}
1980	return NULL;
1981}
1982
1983static struct drm_dp_mst_port *
1984drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr *mgr,
1985				       struct drm_dp_mst_port *port)
1986{
1987	struct drm_dp_mst_port *rport = NULL;
1988
1989	mutex_lock(&mgr->lock);
1990	if (mgr->mst_primary) {
1991		rport = drm_dp_mst_topology_get_port_validated_locked(
1992		    mgr->mst_primary, port);
1993
1994		if (rport && !drm_dp_mst_topology_try_get_port(rport))
1995			rport = NULL;
1996	}
1997	mutex_unlock(&mgr->lock);
1998	return rport;
1999}
2000
2001static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
2002{
2003	struct drm_dp_mst_port *port;
2004	int ret;
2005
2006	list_for_each_entry(port, &mstb->ports, next) {
2007		if (port->port_num == port_num) {
2008			ret = drm_dp_mst_topology_try_get_port(port);
2009			return ret ? port : NULL;
2010		}
2011	}
2012
2013	return NULL;
2014}
2015
2016/*
2017 * calculate a new RAD for this MST branch device
2018 * if parent has an LCT of 2 then it has 1 nibble of RAD,
2019 * if parent has an LCT of 3 then it has 2 nibbles of RAD,
2020 */
2021static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
2022				 u8 *rad)
2023{
2024	int parent_lct = port->parent->lct;
2025	int shift = 4;
2026	int idx = (parent_lct - 1) / 2;
2027
2028	if (parent_lct > 1) {
2029		memcpy(rad, port->parent->rad, idx + 1);
2030		shift = (parent_lct % 2) ? 4 : 0;
2031	} else
2032		rad[0] = 0;
2033
2034	rad[idx] |= port->port_num << shift;
2035	return parent_lct + 1;
2036}
2037
2038static bool drm_dp_mst_is_end_device(u8 pdt, bool mcs)
2039{
2040	switch (pdt) {
2041	case DP_PEER_DEVICE_DP_LEGACY_CONV:
2042	case DP_PEER_DEVICE_SST_SINK:
2043		return true;
2044	case DP_PEER_DEVICE_MST_BRANCHING:
2045		/* For sst branch device */
2046		if (!mcs)
2047			return true;
2048
2049		return false;
2050	}
2051	return true;
2052}
2053
2054static int
2055drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt,
2056		    bool new_mcs)
2057{
2058	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2059	struct drm_dp_mst_branch *mstb;
2060	u8 rad[8], lct;
2061	int ret = 0;
2062
2063	if (port->pdt == new_pdt && port->mcs == new_mcs)
2064		return 0;
2065
2066	/* Teardown the old pdt, if there is one */
2067	if (port->pdt != DP_PEER_DEVICE_NONE) {
2068		if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2069			/*
2070			 * If the new PDT would also have an i2c bus,
2071			 * don't bother with reregistering it
2072			 */
2073			if (new_pdt != DP_PEER_DEVICE_NONE &&
2074			    drm_dp_mst_is_end_device(new_pdt, new_mcs)) {
2075				port->pdt = new_pdt;
2076				port->mcs = new_mcs;
2077				return 0;
2078			}
2079
2080			/* remove i2c over sideband */
2081			drm_dp_mst_unregister_i2c_bus(port);
2082		} else {
2083			mutex_lock(&mgr->lock);
2084			drm_dp_mst_topology_put_mstb(port->mstb);
2085			port->mstb = NULL;
2086			mutex_unlock(&mgr->lock);
2087		}
2088	}
2089
2090	port->pdt = new_pdt;
2091	port->mcs = new_mcs;
2092
2093	if (port->pdt != DP_PEER_DEVICE_NONE) {
2094		if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2095			/* add i2c over sideband */
2096			ret = drm_dp_mst_register_i2c_bus(port);
2097		} else {
2098			lct = drm_dp_calculate_rad(port, rad);
2099			mstb = drm_dp_add_mst_branch_device(lct, rad);
2100			if (!mstb) {
2101				ret = -ENOMEM;
2102				drm_err(mgr->dev, "Failed to create MSTB for port %p", port);
2103				goto out;
2104			}
2105
2106			mutex_lock(&mgr->lock);
2107			port->mstb = mstb;
2108			mstb->mgr = port->mgr;
2109			mstb->port_parent = port;
2110
2111			/*
2112			 * Make sure this port's memory allocation stays
2113			 * around until its child MSTB releases it
2114			 */
2115			drm_dp_mst_get_port_malloc(port);
2116			mutex_unlock(&mgr->lock);
2117
2118			/* And make sure we send a link address for this */
2119			ret = 1;
2120		}
2121	}
2122
2123out:
2124	if (ret < 0)
2125		port->pdt = DP_PEER_DEVICE_NONE;
2126	return ret;
2127}
2128
2129/**
2130 * drm_dp_mst_dpcd_read() - read a series of bytes from the DPCD via sideband
2131 * @aux: Fake sideband AUX CH
2132 * @offset: address of the (first) register to read
2133 * @buffer: buffer to store the register values
2134 * @size: number of bytes in @buffer
2135 *
2136 * Performs the same functionality for remote devices via
2137 * sideband messaging as drm_dp_dpcd_read() does for local
2138 * devices via actual AUX CH.
2139 *
2140 * Return: Number of bytes read, or negative error code on failure.
2141 */
2142ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
2143			     unsigned int offset, void *buffer, size_t size)
2144{
2145	struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2146						    aux);
2147
2148	return drm_dp_send_dpcd_read(port->mgr, port,
2149				     offset, size, buffer);
2150}
2151
2152/**
2153 * drm_dp_mst_dpcd_write() - write a series of bytes to the DPCD via sideband
2154 * @aux: Fake sideband AUX CH
2155 * @offset: address of the (first) register to write
2156 * @buffer: buffer containing the values to write
2157 * @size: number of bytes in @buffer
2158 *
2159 * Performs the same functionality for remote devices via
2160 * sideband messaging as drm_dp_dpcd_write() does for local
2161 * devices via actual AUX CH.
2162 *
2163 * Return: number of bytes written on success, negative error code on failure.
2164 */
2165ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
2166			      unsigned int offset, void *buffer, size_t size)
2167{
2168	struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2169						    aux);
2170
2171	return drm_dp_send_dpcd_write(port->mgr, port,
2172				      offset, size, buffer);
2173}
2174
2175static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
2176{
2177	int ret = 0;
2178
2179	memcpy(mstb->guid, guid, 16);
2180
2181	if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
2182		if (mstb->port_parent) {
2183			ret = drm_dp_send_dpcd_write(mstb->mgr,
2184						     mstb->port_parent,
2185						     DP_GUID, 16, mstb->guid);
2186		} else {
2187			ret = drm_dp_dpcd_write(mstb->mgr->aux,
2188						DP_GUID, mstb->guid, 16);
2189		}
2190	}
2191
2192	if (ret < 16 && ret > 0)
2193		return -EPROTO;
2194
2195	return ret == 16 ? 0 : ret;
2196}
2197
2198static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
2199				int pnum,
2200				char *proppath,
2201				size_t proppath_size)
2202{
2203	int i;
2204	char temp[8];
2205
2206	snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
2207	for (i = 0; i < (mstb->lct - 1); i++) {
2208		int shift = (i % 2) ? 0 : 4;
2209		int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
2210
2211		snprintf(temp, sizeof(temp), "-%d", port_num);
2212		strlcat(proppath, temp, proppath_size);
2213	}
2214	snprintf(temp, sizeof(temp), "-%d", pnum);
2215	strlcat(proppath, temp, proppath_size);
2216}
2217
2218/**
2219 * drm_dp_mst_connector_late_register() - Late MST connector registration
2220 * @connector: The MST connector
2221 * @port: The MST port for this connector
2222 *
2223 * Helper to register the remote aux device for this MST port. Drivers should
2224 * call this from their mst connector's late_register hook to enable MST aux
2225 * devices.
2226 *
2227 * Return: 0 on success, negative error code on failure.
2228 */
2229int drm_dp_mst_connector_late_register(struct drm_connector *connector,
2230				       struct drm_dp_mst_port *port)
2231{
2232	drm_dbg_kms(port->mgr->dev, "registering %s remote bus for %s\n",
2233		    port->aux.name, connector->kdev->kobj.name);
2234
2235	port->aux.dev = connector->kdev;
2236	return drm_dp_aux_register_devnode(&port->aux);
2237}
2238EXPORT_SYMBOL(drm_dp_mst_connector_late_register);
2239
2240/**
2241 * drm_dp_mst_connector_early_unregister() - Early MST connector unregistration
2242 * @connector: The MST connector
2243 * @port: The MST port for this connector
2244 *
2245 * Helper to unregister the remote aux device for this MST port, registered by
2246 * drm_dp_mst_connector_late_register(). Drivers should call this from their mst
2247 * connector's early_unregister hook.
2248 */
2249void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
2250					   struct drm_dp_mst_port *port)
2251{
2252	drm_dbg_kms(port->mgr->dev, "unregistering %s remote bus for %s\n",
2253		    port->aux.name, connector->kdev->kobj.name);
2254	drm_dp_aux_unregister_devnode(&port->aux);
2255}
2256EXPORT_SYMBOL(drm_dp_mst_connector_early_unregister);
2257
2258static void
2259drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb,
2260			      struct drm_dp_mst_port *port)
2261{
2262	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2263	char proppath[255];
2264	int ret;
2265
2266	build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
2267	port->connector = mgr->cbs->add_connector(mgr, port, proppath);
2268	if (!port->connector) {
2269		ret = -ENOMEM;
2270		goto error;
2271	}
2272
2273	if (port->pdt != DP_PEER_DEVICE_NONE &&
2274	    drm_dp_mst_is_end_device(port->pdt, port->mcs) &&
2275	    port->port_num >= DP_MST_LOGICAL_PORT_0)
2276		port->cached_edid = drm_edid_read_ddc(port->connector,
2277						      &port->aux.ddc);
2278
2279	drm_connector_register(port->connector);
2280	return;
2281
2282error:
2283	drm_err(mgr->dev, "Failed to create connector for port %p: %d\n", port, ret);
2284}
2285
2286/*
2287 * Drop a topology reference, and unlink the port from the in-memory topology
2288 * layout
2289 */
2290static void
2291drm_dp_mst_topology_unlink_port(struct drm_dp_mst_topology_mgr *mgr,
2292				struct drm_dp_mst_port *port)
2293{
2294	mutex_lock(&mgr->lock);
2295	port->parent->num_ports--;
2296	list_del(&port->next);
2297	mutex_unlock(&mgr->lock);
2298	drm_dp_mst_topology_put_port(port);
2299}
2300
2301static struct drm_dp_mst_port *
2302drm_dp_mst_add_port(struct drm_device *dev,
2303		    struct drm_dp_mst_topology_mgr *mgr,
2304		    struct drm_dp_mst_branch *mstb, u8 port_number)
2305{
2306	struct drm_dp_mst_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
2307
2308	if (!port)
2309		return NULL;
2310
2311	kref_init(&port->topology_kref);
2312	kref_init(&port->malloc_kref);
2313	port->parent = mstb;
2314	port->port_num = port_number;
2315	port->mgr = mgr;
2316	port->aux.name = "DPMST";
2317	port->aux.dev = dev->dev;
2318	port->aux.is_remote = true;
2319
2320	/* initialize the MST downstream port's AUX crc work queue */
2321	port->aux.drm_dev = dev;
2322	drm_dp_remote_aux_init(&port->aux);
2323
2324	/*
2325	 * Make sure the memory allocation for our parent branch stays
2326	 * around until our own memory allocation is released
2327	 */
2328	drm_dp_mst_get_mstb_malloc(mstb);
2329
2330	return port;
2331}
2332
2333static int
2334drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
2335				    struct drm_device *dev,
2336				    struct drm_dp_link_addr_reply_port *port_msg)
2337{
2338	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2339	struct drm_dp_mst_port *port;
2340	int old_ddps = 0, ret;
2341	u8 new_pdt = DP_PEER_DEVICE_NONE;
2342	bool new_mcs = 0;
2343	bool created = false, send_link_addr = false, changed = false;
2344
2345	port = drm_dp_get_port(mstb, port_msg->port_number);
2346	if (!port) {
2347		port = drm_dp_mst_add_port(dev, mgr, mstb,
2348					   port_msg->port_number);
2349		if (!port)
2350			return -ENOMEM;
2351		created = true;
2352		changed = true;
2353	} else if (!port->input && port_msg->input_port && port->connector) {
2354		/* Since port->connector can't be changed here, we create a
2355		 * new port if input_port changes from 0 to 1
2356		 */
2357		drm_dp_mst_topology_unlink_port(mgr, port);
2358		drm_dp_mst_topology_put_port(port);
2359		port = drm_dp_mst_add_port(dev, mgr, mstb,
2360					   port_msg->port_number);
2361		if (!port)
2362			return -ENOMEM;
2363		changed = true;
2364		created = true;
2365	} else if (port->input && !port_msg->input_port) {
2366		changed = true;
2367	} else if (port->connector) {
2368		/* We're updating a port that's exposed to userspace, so do it
2369		 * under lock
2370		 */
2371		drm_modeset_lock(&mgr->base.lock, NULL);
2372
2373		old_ddps = port->ddps;
2374		changed = port->ddps != port_msg->ddps ||
2375			(port->ddps &&
2376			 (port->ldps != port_msg->legacy_device_plug_status ||
2377			  port->dpcd_rev != port_msg->dpcd_revision ||
2378			  port->mcs != port_msg->mcs ||
2379			  port->pdt != port_msg->peer_device_type ||
2380			  port->num_sdp_stream_sinks !=
2381			  port_msg->num_sdp_stream_sinks));
2382	}
2383
2384	port->input = port_msg->input_port;
2385	if (!port->input)
2386		new_pdt = port_msg->peer_device_type;
2387	new_mcs = port_msg->mcs;
2388	port->ddps = port_msg->ddps;
2389	port->ldps = port_msg->legacy_device_plug_status;
2390	port->dpcd_rev = port_msg->dpcd_revision;
2391	port->num_sdp_streams = port_msg->num_sdp_streams;
2392	port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
2393
2394	/* manage mstb port lists with mgr lock - take a reference
2395	   for this list */
2396	if (created) {
2397		mutex_lock(&mgr->lock);
2398		drm_dp_mst_topology_get_port(port);
2399		list_add(&port->next, &mstb->ports);
2400		mstb->num_ports++;
2401		mutex_unlock(&mgr->lock);
2402	}
2403
2404	/*
2405	 * Reprobe PBN caps on both hotplug, and when re-probing the link
2406	 * for our parent mstb
2407	 */
2408	if (old_ddps != port->ddps || !created) {
2409		if (port->ddps && !port->input) {
2410			ret = drm_dp_send_enum_path_resources(mgr, mstb,
2411							      port);
2412			if (ret == 1)
2413				changed = true;
2414		} else {
2415			port->full_pbn = 0;
2416		}
2417	}
2418
2419	ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2420	if (ret == 1) {
2421		send_link_addr = true;
2422	} else if (ret < 0) {
2423		drm_err(dev, "Failed to change PDT on port %p: %d\n", port, ret);
2424		goto fail;
2425	}
2426
2427	/*
2428	 * If this port wasn't just created, then we're reprobing because
2429	 * we're coming out of suspend. In this case, always resend the link
2430	 * address if there's an MSTB on this port
2431	 */
2432	if (!created && port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
2433	    port->mcs)
2434		send_link_addr = true;
2435
2436	if (port->connector)
2437		drm_modeset_unlock(&mgr->base.lock);
2438	else if (!port->input)
2439		drm_dp_mst_port_add_connector(mstb, port);
2440
2441	if (send_link_addr && port->mstb) {
2442		ret = drm_dp_send_link_address(mgr, port->mstb);
2443		if (ret == 1) /* MSTB below us changed */
2444			changed = true;
2445		else if (ret < 0)
2446			goto fail_put;
2447	}
2448
2449	/* put reference to this port */
2450	drm_dp_mst_topology_put_port(port);
2451	return changed;
2452
2453fail:
2454	drm_dp_mst_topology_unlink_port(mgr, port);
2455	if (port->connector)
2456		drm_modeset_unlock(&mgr->base.lock);
2457fail_put:
2458	drm_dp_mst_topology_put_port(port);
2459	return ret;
2460}
2461
2462static int
2463drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
2464			    struct drm_dp_connection_status_notify *conn_stat)
2465{
2466	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2467	struct drm_dp_mst_port *port;
2468	int old_ddps, ret;
2469	u8 new_pdt;
2470	bool new_mcs;
2471	bool dowork = false, create_connector = false;
2472
2473	port = drm_dp_get_port(mstb, conn_stat->port_number);
2474	if (!port)
2475		return 0;
2476
2477	if (port->connector) {
2478		if (!port->input && conn_stat->input_port) {
2479			/*
2480			 * We can't remove a connector from an already exposed
2481			 * port, so just throw the port out and make sure we
2482			 * reprobe the link address of it's parent MSTB
2483			 */
2484			drm_dp_mst_topology_unlink_port(mgr, port);
2485			mstb->link_address_sent = false;
2486			dowork = true;
2487			goto out;
2488		}
2489
2490		/* Locking is only needed if the port's exposed to userspace */
2491		drm_modeset_lock(&mgr->base.lock, NULL);
2492	} else if (port->input && !conn_stat->input_port) {
2493		create_connector = true;
2494		/* Reprobe link address so we get num_sdp_streams */
2495		mstb->link_address_sent = false;
2496		dowork = true;
2497	}
2498
2499	old_ddps = port->ddps;
2500	port->input = conn_stat->input_port;
2501	port->ldps = conn_stat->legacy_device_plug_status;
2502	port->ddps = conn_stat->displayport_device_plug_status;
2503
2504	if (old_ddps != port->ddps) {
2505		if (port->ddps && !port->input)
2506			drm_dp_send_enum_path_resources(mgr, mstb, port);
2507		else
2508			port->full_pbn = 0;
2509	}
2510
2511	new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type;
2512	new_mcs = conn_stat->message_capability_status;
2513	ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2514	if (ret == 1) {
2515		dowork = true;
2516	} else if (ret < 0) {
2517		drm_err(mgr->dev, "Failed to change PDT for port %p: %d\n", port, ret);
2518		dowork = false;
2519	}
2520
2521	if (port->connector)
2522		drm_modeset_unlock(&mgr->base.lock);
2523	else if (create_connector)
2524		drm_dp_mst_port_add_connector(mstb, port);
2525
2526out:
2527	drm_dp_mst_topology_put_port(port);
2528	return dowork;
2529}
2530
2531static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
2532							       u8 lct, u8 *rad)
2533{
2534	struct drm_dp_mst_branch *mstb;
2535	struct drm_dp_mst_port *port;
2536	int i, ret;
2537	/* find the port by iterating down */
2538
2539	mutex_lock(&mgr->lock);
2540	mstb = mgr->mst_primary;
2541
2542	if (!mstb)
2543		goto out;
2544
2545	for (i = 0; i < lct - 1; i++) {
2546		int shift = (i % 2) ? 0 : 4;
2547		int port_num = (rad[i / 2] >> shift) & 0xf;
2548
2549		list_for_each_entry(port, &mstb->ports, next) {
2550			if (port->port_num == port_num) {
2551				mstb = port->mstb;
2552				if (!mstb) {
2553					drm_err(mgr->dev,
2554						"failed to lookup MSTB with lct %d, rad %02x\n",
2555						lct, rad[0]);
2556					goto out;
2557				}
2558
2559				break;
2560			}
2561		}
2562	}
2563	ret = drm_dp_mst_topology_try_get_mstb(mstb);
2564	if (!ret)
2565		mstb = NULL;
2566out:
2567	mutex_unlock(&mgr->lock);
2568	return mstb;
2569}
2570
2571static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
2572	struct drm_dp_mst_branch *mstb,
2573	const uint8_t *guid)
2574{
2575	struct drm_dp_mst_branch *found_mstb;
2576	struct drm_dp_mst_port *port;
2577
2578	if (!mstb)
2579		return NULL;
2580
2581	if (memcmp(mstb->guid, guid, 16) == 0)
2582		return mstb;
2583
2584
2585	list_for_each_entry(port, &mstb->ports, next) {
2586		found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid);
2587
2588		if (found_mstb)
2589			return found_mstb;
2590	}
2591
2592	return NULL;
2593}
2594
2595static struct drm_dp_mst_branch *
2596drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr *mgr,
2597				     const uint8_t *guid)
2598{
2599	struct drm_dp_mst_branch *mstb;
2600	int ret;
2601
2602	/* find the port by iterating down */
2603	mutex_lock(&mgr->lock);
2604
2605	mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
2606	if (mstb) {
2607		ret = drm_dp_mst_topology_try_get_mstb(mstb);
2608		if (!ret)
2609			mstb = NULL;
2610	}
2611
2612	mutex_unlock(&mgr->lock);
2613	return mstb;
2614}
2615
2616static int drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2617					       struct drm_dp_mst_branch *mstb)
2618{
2619	struct drm_dp_mst_port *port;
2620	int ret;
2621	bool changed = false;
2622
2623	if (!mstb->link_address_sent) {
2624		ret = drm_dp_send_link_address(mgr, mstb);
2625		if (ret == 1)
2626			changed = true;
2627		else if (ret < 0)
2628			return ret;
2629	}
2630
2631	list_for_each_entry(port, &mstb->ports, next) {
2632		if (port->input || !port->ddps || !port->mstb)
2633			continue;
2634
2635		ret = drm_dp_check_and_send_link_address(mgr, port->mstb);
2636		if (ret == 1)
2637			changed = true;
2638		else if (ret < 0)
2639			return ret;
2640	}
2641
2642	return changed;
2643}
2644
2645static void drm_dp_mst_link_probe_work(struct work_struct *work)
2646{
2647	struct drm_dp_mst_topology_mgr *mgr =
2648		container_of(work, struct drm_dp_mst_topology_mgr, work);
2649	struct drm_device *dev = mgr->dev;
2650	struct drm_dp_mst_branch *mstb;
2651	int ret;
2652	bool clear_payload_id_table;
2653
2654	mutex_lock(&mgr->probe_lock);
2655
2656	mutex_lock(&mgr->lock);
2657	clear_payload_id_table = !mgr->payload_id_table_cleared;
2658	mgr->payload_id_table_cleared = true;
2659
2660	mstb = mgr->mst_primary;
2661	if (mstb) {
2662		ret = drm_dp_mst_topology_try_get_mstb(mstb);
2663		if (!ret)
2664			mstb = NULL;
2665	}
2666	mutex_unlock(&mgr->lock);
2667	if (!mstb) {
2668		mutex_unlock(&mgr->probe_lock);
2669		return;
2670	}
2671
2672	/*
2673	 * Certain branch devices seem to incorrectly report an available_pbn
2674	 * of 0 on downstream sinks, even after clearing the
2675	 * DP_PAYLOAD_ALLOCATE_* registers in
2676	 * drm_dp_mst_topology_mgr_set_mst(). Namely, the CableMatters USB-C
2677	 * 2x DP hub. Sending a CLEAR_PAYLOAD_ID_TABLE message seems to make
2678	 * things work again.
2679	 */
2680	if (clear_payload_id_table) {
2681		drm_dbg_kms(dev, "Clearing payload ID table\n");
2682		drm_dp_send_clear_payload_id_table(mgr, mstb);
2683	}
2684
2685	ret = drm_dp_check_and_send_link_address(mgr, mstb);
2686	drm_dp_mst_topology_put_mstb(mstb);
2687
2688	mutex_unlock(&mgr->probe_lock);
2689	if (ret > 0)
2690		drm_kms_helper_hotplug_event(dev);
2691}
2692
2693static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
2694				 u8 *guid)
2695{
2696	u64 salt;
2697
2698	if (memchr_inv(guid, 0, 16))
2699		return true;
2700
2701	salt = get_jiffies_64();
2702
2703	memcpy(&guid[0], &salt, sizeof(u64));
2704	memcpy(&guid[8], &salt, sizeof(u64));
2705
2706	return false;
2707}
2708
2709static void build_dpcd_read(struct drm_dp_sideband_msg_tx *msg,
2710			    u8 port_num, u32 offset, u8 num_bytes)
2711{
2712	struct drm_dp_sideband_msg_req_body req;
2713
2714	req.req_type = DP_REMOTE_DPCD_READ;
2715	req.u.dpcd_read.port_number = port_num;
2716	req.u.dpcd_read.dpcd_address = offset;
2717	req.u.dpcd_read.num_bytes = num_bytes;
2718	drm_dp_encode_sideband_req(&req, msg);
2719}
2720
2721static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
2722				    bool up, u8 *msg, int len)
2723{
2724	int ret;
2725	int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
2726	int tosend, total, offset;
2727	int retries = 0;
2728
2729retry:
2730	total = len;
2731	offset = 0;
2732	do {
2733		tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
2734
2735		ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
2736					&msg[offset],
2737					tosend);
2738		if (ret != tosend) {
2739			if (ret == -EIO && retries < 5) {
2740				retries++;
2741				goto retry;
2742			}
2743			drm_dbg_kms(mgr->dev, "failed to dpcd write %d %d\n", tosend, ret);
2744
2745			return -EIO;
2746		}
2747		offset += tosend;
2748		total -= tosend;
2749	} while (total > 0);
2750	return 0;
2751}
2752
2753static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
2754				  struct drm_dp_sideband_msg_tx *txmsg)
2755{
2756	struct drm_dp_mst_branch *mstb = txmsg->dst;
2757	u8 req_type;
2758
2759	req_type = txmsg->msg[0] & 0x7f;
2760	if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
2761		req_type == DP_RESOURCE_STATUS_NOTIFY ||
2762		req_type == DP_CLEAR_PAYLOAD_ID_TABLE)
2763		hdr->broadcast = 1;
2764	else
2765		hdr->broadcast = 0;
2766	hdr->path_msg = txmsg->path_msg;
2767	if (hdr->broadcast) {
2768		hdr->lct = 1;
2769		hdr->lcr = 6;
2770	} else {
2771		hdr->lct = mstb->lct;
2772		hdr->lcr = mstb->lct - 1;
2773	}
2774
2775	memcpy(hdr->rad, mstb->rad, hdr->lct / 2);
2776
2777	return 0;
2778}
2779/*
2780 * process a single block of the next message in the sideband queue
2781 */
2782static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
2783				   struct drm_dp_sideband_msg_tx *txmsg,
2784				   bool up)
2785{
2786	u8 chunk[48];
2787	struct drm_dp_sideband_msg_hdr hdr;
2788	int len, space, idx, tosend;
2789	int ret;
2790
2791	if (txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
2792		return 0;
2793
2794	memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
2795
2796	if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED)
2797		txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
2798
2799	/* make hdr from dst mst */
2800	ret = set_hdr_from_dst_qlock(&hdr, txmsg);
2801	if (ret < 0)
2802		return ret;
2803
2804	/* amount left to send in this message */
2805	len = txmsg->cur_len - txmsg->cur_offset;
2806
2807	/* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
2808	space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
2809
2810	tosend = min(len, space);
2811	if (len == txmsg->cur_len)
2812		hdr.somt = 1;
2813	if (space >= len)
2814		hdr.eomt = 1;
2815
2816
2817	hdr.msg_len = tosend + 1;
2818	drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
2819	memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
2820	/* add crc at end */
2821	drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
2822	idx += tosend + 1;
2823
2824	ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
2825	if (ret) {
2826		if (drm_debug_enabled(DRM_UT_DP)) {
2827			struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2828
2829			drm_printf(&p, "sideband msg failed to send\n");
2830			drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2831		}
2832		return ret;
2833	}
2834
2835	txmsg->cur_offset += tosend;
2836	if (txmsg->cur_offset == txmsg->cur_len) {
2837		txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
2838		return 1;
2839	}
2840	return 0;
2841}
2842
2843static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
2844{
2845	struct drm_dp_sideband_msg_tx *txmsg;
2846	int ret;
2847
2848	WARN_ON(!mutex_is_locked(&mgr->qlock));
2849
2850	/* construct a chunk from the first msg in the tx_msg queue */
2851	if (list_empty(&mgr->tx_msg_downq))
2852		return;
2853
2854	txmsg = list_first_entry(&mgr->tx_msg_downq,
2855				 struct drm_dp_sideband_msg_tx, next);
2856	ret = process_single_tx_qlock(mgr, txmsg, false);
2857	if (ret < 0) {
2858		drm_dbg_kms(mgr->dev, "failed to send msg in q %d\n", ret);
2859		list_del(&txmsg->next);
2860		txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
2861		wake_up_all(&mgr->tx_waitq);
2862	}
2863}
2864
2865static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
2866				 struct drm_dp_sideband_msg_tx *txmsg)
2867{
2868	mutex_lock(&mgr->qlock);
2869	list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
2870
2871	if (drm_debug_enabled(DRM_UT_DP)) {
2872		struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2873
2874		drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2875	}
2876
2877	if (list_is_singular(&mgr->tx_msg_downq))
2878		process_single_down_tx_qlock(mgr);
2879	mutex_unlock(&mgr->qlock);
2880}
2881
2882static void
2883drm_dp_dump_link_address(const struct drm_dp_mst_topology_mgr *mgr,
2884			 struct drm_dp_link_address_ack_reply *reply)
2885{
2886	struct drm_dp_link_addr_reply_port *port_reply;
2887	int i;
2888
2889	for (i = 0; i < reply->nports; i++) {
2890		port_reply = &reply->ports[i];
2891		drm_dbg_kms(mgr->dev,
2892			    "port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n",
2893			    i,
2894			    port_reply->input_port,
2895			    port_reply->peer_device_type,
2896			    port_reply->port_number,
2897			    port_reply->dpcd_revision,
2898			    port_reply->mcs,
2899			    port_reply->ddps,
2900			    port_reply->legacy_device_plug_status,
2901			    port_reply->num_sdp_streams,
2902			    port_reply->num_sdp_stream_sinks);
2903	}
2904}
2905
2906static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2907				     struct drm_dp_mst_branch *mstb)
2908{
2909	struct drm_dp_sideband_msg_tx *txmsg;
2910	struct drm_dp_link_address_ack_reply *reply;
2911	struct drm_dp_mst_port *port, *tmp;
2912	int i, ret, port_mask = 0;
2913	bool changed = false;
2914
2915	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2916	if (!txmsg)
2917		return -ENOMEM;
2918
2919	txmsg->dst = mstb;
2920	build_link_address(txmsg);
2921
2922	mstb->link_address_sent = true;
2923	drm_dp_queue_down_tx(mgr, txmsg);
2924
2925	/* FIXME: Actually do some real error handling here */
2926	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2927	if (ret <= 0) {
2928		drm_err(mgr->dev, "Sending link address failed with %d\n", ret);
2929		goto out;
2930	}
2931	if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
2932		drm_err(mgr->dev, "link address NAK received\n");
2933		ret = -EIO;
2934		goto out;
2935	}
2936
2937	reply = &txmsg->reply.u.link_addr;
2938	drm_dbg_kms(mgr->dev, "link address reply: %d\n", reply->nports);
2939	drm_dp_dump_link_address(mgr, reply);
2940
2941	ret = drm_dp_check_mstb_guid(mstb, reply->guid);
2942	if (ret) {
2943		char buf[64];
2944
2945		drm_dp_mst_rad_to_str(mstb->rad, mstb->lct, buf, sizeof(buf));
2946		drm_err(mgr->dev, "GUID check on %s failed: %d\n", buf, ret);
2947		goto out;
2948	}
2949
2950	for (i = 0; i < reply->nports; i++) {
2951		port_mask |= BIT(reply->ports[i].port_number);
2952		ret = drm_dp_mst_handle_link_address_port(mstb, mgr->dev,
2953							  &reply->ports[i]);
2954		if (ret == 1)
2955			changed = true;
2956		else if (ret < 0)
2957			goto out;
2958	}
2959
2960	/* Prune any ports that are currently a part of mstb in our in-memory
2961	 * topology, but were not seen in this link address. Usually this
2962	 * means that they were removed while the topology was out of sync,
2963	 * e.g. during suspend/resume
2964	 */
2965	mutex_lock(&mgr->lock);
2966	list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
2967		if (port_mask & BIT(port->port_num))
2968			continue;
2969
2970		drm_dbg_kms(mgr->dev, "port %d was not in link address, removing\n",
2971			    port->port_num);
2972		list_del(&port->next);
2973		drm_dp_mst_topology_put_port(port);
2974		changed = true;
2975	}
2976	mutex_unlock(&mgr->lock);
2977
2978out:
2979	if (ret <= 0)
2980		mstb->link_address_sent = false;
2981	kfree(txmsg);
2982	return ret < 0 ? ret : changed;
2983}
2984
2985static void
2986drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
2987				   struct drm_dp_mst_branch *mstb)
2988{
2989	struct drm_dp_sideband_msg_tx *txmsg;
2990	int ret;
2991
2992	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2993	if (!txmsg)
2994		return;
2995
2996	txmsg->dst = mstb;
2997	build_clear_payload_id_table(txmsg);
2998
2999	drm_dp_queue_down_tx(mgr, txmsg);
3000
3001	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3002	if (ret > 0 && txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3003		drm_dbg_kms(mgr->dev, "clear payload table id nak received\n");
3004
3005	kfree(txmsg);
3006}
3007
3008static int
3009drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
3010				struct drm_dp_mst_branch *mstb,
3011				struct drm_dp_mst_port *port)
3012{
3013	struct drm_dp_enum_path_resources_ack_reply *path_res;
3014	struct drm_dp_sideband_msg_tx *txmsg;
3015	int ret;
3016
3017	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3018	if (!txmsg)
3019		return -ENOMEM;
3020
3021	txmsg->dst = mstb;
3022	build_enum_path_resources(txmsg, port->port_num);
3023
3024	drm_dp_queue_down_tx(mgr, txmsg);
3025
3026	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3027	if (ret > 0) {
3028		ret = 0;
3029		path_res = &txmsg->reply.u.path_resources;
3030
3031		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3032			drm_dbg_kms(mgr->dev, "enum path resources nak received\n");
3033		} else {
3034			if (port->port_num != path_res->port_number)
3035				DRM_ERROR("got incorrect port in response\n");
3036
3037			drm_dbg_kms(mgr->dev, "enum path resources %d: %d %d\n",
3038				    path_res->port_number,
3039				    path_res->full_payload_bw_number,
3040				    path_res->avail_payload_bw_number);
3041
3042			/*
3043			 * If something changed, make sure we send a
3044			 * hotplug
3045			 */
3046			if (port->full_pbn != path_res->full_payload_bw_number ||
3047			    port->fec_capable != path_res->fec_capable)
3048				ret = 1;
3049
3050			port->full_pbn = path_res->full_payload_bw_number;
3051			port->fec_capable = path_res->fec_capable;
3052		}
3053	}
3054
3055	kfree(txmsg);
3056	return ret;
3057}
3058
3059static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb)
3060{
3061	if (!mstb->port_parent)
3062		return NULL;
3063
3064	if (mstb->port_parent->mstb != mstb)
3065		return mstb->port_parent;
3066
3067	return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
3068}
3069
3070/*
3071 * Searches upwards in the topology starting from mstb to try to find the
3072 * closest available parent of mstb that's still connected to the rest of the
3073 * topology. This can be used in order to perform operations like releasing
3074 * payloads, where the branch device which owned the payload may no longer be
3075 * around and thus would require that the payload on the last living relative
3076 * be freed instead.
3077 */
3078static struct drm_dp_mst_branch *
3079drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
3080					struct drm_dp_mst_branch *mstb,
3081					int *port_num)
3082{
3083	struct drm_dp_mst_branch *rmstb = NULL;
3084	struct drm_dp_mst_port *found_port;
3085
3086	mutex_lock(&mgr->lock);
3087	if (!mgr->mst_primary)
3088		goto out;
3089
3090	do {
3091		found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
3092		if (!found_port)
3093			break;
3094
3095		if (drm_dp_mst_topology_try_get_mstb(found_port->parent)) {
3096			rmstb = found_port->parent;
3097			*port_num = found_port->port_num;
3098		} else {
3099			/* Search again, starting from this parent */
3100			mstb = found_port->parent;
3101		}
3102	} while (!rmstb);
3103out:
3104	mutex_unlock(&mgr->lock);
3105	return rmstb;
3106}
3107
3108static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
3109				   struct drm_dp_mst_port *port,
3110				   int id,
3111				   int pbn)
3112{
3113	struct drm_dp_sideband_msg_tx *txmsg;
3114	struct drm_dp_mst_branch *mstb;
3115	int ret, port_num;
3116	u8 sinks[DRM_DP_MAX_SDP_STREAMS];
3117	int i;
3118
3119	port_num = port->port_num;
3120	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3121	if (!mstb) {
3122		mstb = drm_dp_get_last_connected_port_and_mstb(mgr,
3123							       port->parent,
3124							       &port_num);
3125
3126		if (!mstb)
3127			return -EINVAL;
3128	}
3129
3130	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3131	if (!txmsg) {
3132		ret = -ENOMEM;
3133		goto fail_put;
3134	}
3135
3136	for (i = 0; i < port->num_sdp_streams; i++)
3137		sinks[i] = i;
3138
3139	txmsg->dst = mstb;
3140	build_allocate_payload(txmsg, port_num,
3141			       id,
3142			       pbn, port->num_sdp_streams, sinks);
3143
3144	drm_dp_queue_down_tx(mgr, txmsg);
3145
3146	/*
3147	 * FIXME: there is a small chance that between getting the last
3148	 * connected mstb and sending the payload message, the last connected
3149	 * mstb could also be removed from the topology. In the future, this
3150	 * needs to be fixed by restarting the
3151	 * drm_dp_get_last_connected_port_and_mstb() search in the event of a
3152	 * timeout if the topology is still connected to the system.
3153	 */
3154	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3155	if (ret > 0) {
3156		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3157			ret = -EINVAL;
3158		else
3159			ret = 0;
3160	}
3161	kfree(txmsg);
3162fail_put:
3163	drm_dp_mst_topology_put_mstb(mstb);
3164	return ret;
3165}
3166
3167int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
3168				 struct drm_dp_mst_port *port, bool power_up)
3169{
3170	struct drm_dp_sideband_msg_tx *txmsg;
3171	int ret;
3172
3173	port = drm_dp_mst_topology_get_port_validated(mgr, port);
3174	if (!port)
3175		return -EINVAL;
3176
3177	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3178	if (!txmsg) {
3179		drm_dp_mst_topology_put_port(port);
3180		return -ENOMEM;
3181	}
3182
3183	txmsg->dst = port->parent;
3184	build_power_updown_phy(txmsg, port->port_num, power_up);
3185	drm_dp_queue_down_tx(mgr, txmsg);
3186
3187	ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg);
3188	if (ret > 0) {
3189		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3190			ret = -EINVAL;
3191		else
3192			ret = 0;
3193	}
3194	kfree(txmsg);
3195	drm_dp_mst_topology_put_port(port);
3196
3197	return ret;
3198}
3199EXPORT_SYMBOL(drm_dp_send_power_updown_phy);
3200
3201int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
3202		struct drm_dp_mst_port *port,
3203		struct drm_dp_query_stream_enc_status_ack_reply *status)
3204{
3205	struct drm_dp_mst_topology_state *state;
3206	struct drm_dp_mst_atomic_payload *payload;
3207	struct drm_dp_sideband_msg_tx *txmsg;
3208	u8 nonce[7];
3209	int ret;
3210
3211	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3212	if (!txmsg)
3213		return -ENOMEM;
3214
3215	port = drm_dp_mst_topology_get_port_validated(mgr, port);
3216	if (!port) {
3217		ret = -EINVAL;
3218		goto out_get_port;
3219	}
3220
3221	get_random_bytes(nonce, sizeof(nonce));
3222
3223	drm_modeset_lock(&mgr->base.lock, NULL);
3224	state = to_drm_dp_mst_topology_state(mgr->base.state);
3225	payload = drm_atomic_get_mst_payload_state(state, port);
3226
3227	/*
3228	 * "Source device targets the QUERY_STREAM_ENCRYPTION_STATUS message
3229	 *  transaction at the MST Branch device directly connected to the
3230	 *  Source"
3231	 */
3232	txmsg->dst = mgr->mst_primary;
3233
3234	build_query_stream_enc_status(txmsg, payload->vcpi, nonce);
3235
3236	drm_dp_queue_down_tx(mgr, txmsg);
3237
3238	ret = drm_dp_mst_wait_tx_reply(mgr->mst_primary, txmsg);
3239	if (ret < 0) {
3240		goto out;
3241	} else if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3242		drm_dbg_kms(mgr->dev, "query encryption status nak received\n");
3243		ret = -ENXIO;
3244		goto out;
3245	}
3246
3247	ret = 0;
3248	memcpy(status, &txmsg->reply.u.enc_status, sizeof(*status));
3249
3250out:
3251	drm_modeset_unlock(&mgr->base.lock);
3252	drm_dp_mst_topology_put_port(port);
3253out_get_port:
3254	kfree(txmsg);
3255	return ret;
3256}
3257EXPORT_SYMBOL(drm_dp_send_query_stream_enc_status);
3258
3259static int drm_dp_create_payload_at_dfp(struct drm_dp_mst_topology_mgr *mgr,
3260					struct drm_dp_mst_atomic_payload *payload)
3261{
3262	return drm_dp_dpcd_write_payload(mgr, payload->vcpi, payload->vc_start_slot,
3263					 payload->time_slots);
3264}
3265
3266static int drm_dp_create_payload_to_remote(struct drm_dp_mst_topology_mgr *mgr,
3267					   struct drm_dp_mst_atomic_payload *payload)
3268{
3269	int ret;
3270	struct drm_dp_mst_port *port = drm_dp_mst_topology_get_port_validated(mgr, payload->port);
3271
3272	if (!port)
3273		return -EIO;
3274
3275	ret = drm_dp_payload_send_msg(mgr, port, payload->vcpi, payload->pbn);
3276	drm_dp_mst_topology_put_port(port);
3277	return ret;
3278}
3279
3280static void drm_dp_destroy_payload_at_remote_and_dfp(struct drm_dp_mst_topology_mgr *mgr,
3281						     struct drm_dp_mst_topology_state *mst_state,
3282						     struct drm_dp_mst_atomic_payload *payload)
3283{
3284	drm_dbg_kms(mgr->dev, "\n");
3285
3286	/* it's okay for these to fail */
3287	if (payload->payload_allocation_status == DRM_DP_MST_PAYLOAD_ALLOCATION_REMOTE) {
3288		drm_dp_payload_send_msg(mgr, payload->port, payload->vcpi, 0);
3289		payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_DFP;
3290	}
3291
3292	if (payload->payload_allocation_status == DRM_DP_MST_PAYLOAD_ALLOCATION_DFP)
3293		drm_dp_dpcd_write_payload(mgr, payload->vcpi, payload->vc_start_slot, 0);
3294}
3295
3296/**
3297 * drm_dp_add_payload_part1() - Execute payload update part 1
3298 * @mgr: Manager to use.
3299 * @mst_state: The MST atomic state
3300 * @payload: The payload to write
3301 *
3302 * Determines the starting time slot for the given payload, and programs the VCPI for this payload
3303 * into the DPCD of DPRX. After calling this, the driver should generate ACT and payload packets.
3304 *
3305 * Returns: 0 on success, error code on failure.
3306 */
3307int drm_dp_add_payload_part1(struct drm_dp_mst_topology_mgr *mgr,
3308			     struct drm_dp_mst_topology_state *mst_state,
3309			     struct drm_dp_mst_atomic_payload *payload)
3310{
3311	struct drm_dp_mst_port *port;
3312	int ret;
3313
3314	/* Update mst mgr info */
3315	if (mgr->payload_count == 0)
3316		mgr->next_start_slot = mst_state->start_slot;
3317
3318	payload->vc_start_slot = mgr->next_start_slot;
3319
3320	mgr->payload_count++;
3321	mgr->next_start_slot += payload->time_slots;
3322
3323	payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_LOCAL;
3324
3325	/* Allocate payload to immediate downstream facing port */
3326	port = drm_dp_mst_topology_get_port_validated(mgr, payload->port);
3327	if (!port) {
3328		drm_dbg_kms(mgr->dev,
3329			    "VCPI %d for port %p not in topology, not creating a payload to remote\n",
3330			    payload->vcpi, payload->port);
3331		return -EIO;
3332	}
3333
3334	ret = drm_dp_create_payload_at_dfp(mgr, payload);
3335	if (ret < 0) {
3336		drm_dbg_kms(mgr->dev, "Failed to create MST payload for port %p: %d\n",
3337			    payload->port, ret);
3338		goto put_port;
3339	}
3340
3341	payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_DFP;
3342
3343put_port:
3344	drm_dp_mst_topology_put_port(port);
3345
3346	return ret;
3347}
3348EXPORT_SYMBOL(drm_dp_add_payload_part1);
3349
3350/**
3351 * drm_dp_remove_payload_part1() - Remove an MST payload along the virtual channel
3352 * @mgr: Manager to use.
3353 * @mst_state: The MST atomic state
3354 * @payload: The payload to remove
3355 *
3356 * Removes a payload along the virtual channel if it was successfully allocated.
3357 * After calling this, the driver should set HW to generate ACT and then switch to new
3358 * payload allocation state.
3359 */
3360void drm_dp_remove_payload_part1(struct drm_dp_mst_topology_mgr *mgr,
3361				 struct drm_dp_mst_topology_state *mst_state,
3362				 struct drm_dp_mst_atomic_payload *payload)
3363{
3364	/* Remove remote payload allocation */
3365	bool send_remove = false;
3366
3367	mutex_lock(&mgr->lock);
3368	send_remove = drm_dp_mst_port_downstream_of_branch(payload->port, mgr->mst_primary);
3369	mutex_unlock(&mgr->lock);
3370
3371	if (send_remove)
3372		drm_dp_destroy_payload_at_remote_and_dfp(mgr, mst_state, payload);
3373	else
3374		drm_dbg_kms(mgr->dev, "Payload for VCPI %d not in topology, not sending remove\n",
3375			    payload->vcpi);
3376
3377	payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_LOCAL;
3378}
3379EXPORT_SYMBOL(drm_dp_remove_payload_part1);
3380
3381/**
3382 * drm_dp_remove_payload_part2() - Remove an MST payload locally
3383 * @mgr: Manager to use.
3384 * @mst_state: The MST atomic state
3385 * @old_payload: The payload with its old state
3386 * @new_payload: The payload with its latest state
3387 *
3388 * Updates the starting time slots of all other payloads which would have been shifted towards
3389 * the start of the payload ID table as a result of removing a payload. Driver should call this
3390 * function whenever it removes a payload in its HW. It's independent to the result of payload
3391 * allocation/deallocation at branch devices along the virtual channel.
3392 */
3393void drm_dp_remove_payload_part2(struct drm_dp_mst_topology_mgr *mgr,
3394				 struct drm_dp_mst_topology_state *mst_state,
3395				 const struct drm_dp_mst_atomic_payload *old_payload,
3396				 struct drm_dp_mst_atomic_payload *new_payload)
3397{
3398	struct drm_dp_mst_atomic_payload *pos;
3399
3400	/* Remove local payload allocation */
3401	list_for_each_entry(pos, &mst_state->payloads, next) {
3402		if (pos != new_payload && pos->vc_start_slot > new_payload->vc_start_slot)
3403			pos->vc_start_slot -= old_payload->time_slots;
3404	}
3405	new_payload->vc_start_slot = -1;
3406
3407	mgr->payload_count--;
3408	mgr->next_start_slot -= old_payload->time_slots;
3409
3410	if (new_payload->delete)
3411		drm_dp_mst_put_port_malloc(new_payload->port);
3412
3413	new_payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_NONE;
3414}
3415EXPORT_SYMBOL(drm_dp_remove_payload_part2);
3416/**
3417 * drm_dp_add_payload_part2() - Execute payload update part 2
3418 * @mgr: Manager to use.
3419 * @state: The global atomic state
3420 * @payload: The payload to update
3421 *
3422 * If @payload was successfully assigned a starting time slot by drm_dp_add_payload_part1(), this
3423 * function will send the sideband messages to finish allocating this payload.
3424 *
3425 * Returns: 0 on success, negative error code on failure.
3426 */
3427int drm_dp_add_payload_part2(struct drm_dp_mst_topology_mgr *mgr,
3428			     struct drm_atomic_state *state,
3429			     struct drm_dp_mst_atomic_payload *payload)
3430{
3431	int ret = 0;
3432
3433	/* Skip failed payloads */
3434	if (payload->payload_allocation_status != DRM_DP_MST_PAYLOAD_ALLOCATION_DFP) {
3435		drm_dbg_kms(state->dev, "Part 1 of payload creation for %s failed, skipping part 2\n",
3436			    payload->port->connector->name);
3437		return -EIO;
3438	}
3439
3440	/* Allocate payload to remote end */
3441	ret = drm_dp_create_payload_to_remote(mgr, payload);
3442	if (ret < 0)
3443		drm_err(mgr->dev, "Step 2 of creating MST payload for %p failed: %d\n",
3444			payload->port, ret);
3445	else
3446		payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_REMOTE;
3447
3448	return ret;
3449}
3450EXPORT_SYMBOL(drm_dp_add_payload_part2);
3451
3452static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
3453				 struct drm_dp_mst_port *port,
3454				 int offset, int size, u8 *bytes)
3455{
3456	int ret = 0;
3457	struct drm_dp_sideband_msg_tx *txmsg;
3458	struct drm_dp_mst_branch *mstb;
3459
3460	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3461	if (!mstb)
3462		return -EINVAL;
3463
3464	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3465	if (!txmsg) {
3466		ret = -ENOMEM;
3467		goto fail_put;
3468	}
3469
3470	build_dpcd_read(txmsg, port->port_num, offset, size);
3471	txmsg->dst = port->parent;
3472
3473	drm_dp_queue_down_tx(mgr, txmsg);
3474
3475	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3476	if (ret < 0)
3477		goto fail_free;
3478
3479	if (txmsg->reply.reply_type == 1) {
3480		drm_dbg_kms(mgr->dev, "mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n",
3481			    mstb, port->port_num, offset, size);
3482		ret = -EIO;
3483		goto fail_free;
3484	}
3485
3486	if (txmsg->reply.u.remote_dpcd_read_ack.num_bytes != size) {
3487		ret = -EPROTO;
3488		goto fail_free;
3489	}
3490
3491	ret = min_t(size_t, txmsg->reply.u.remote_dpcd_read_ack.num_bytes,
3492		    size);
3493	memcpy(bytes, txmsg->reply.u.remote_dpcd_read_ack.bytes, ret);
3494
3495fail_free:
3496	kfree(txmsg);
3497fail_put:
3498	drm_dp_mst_topology_put_mstb(mstb);
3499
3500	return ret;
3501}
3502
3503static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
3504				  struct drm_dp_mst_port *port,
3505				  int offset, int size, u8 *bytes)
3506{
3507	int ret;
3508	struct drm_dp_sideband_msg_tx *txmsg;
3509	struct drm_dp_mst_branch *mstb;
3510
3511	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3512	if (!mstb)
3513		return -EINVAL;
3514
3515	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3516	if (!txmsg) {
3517		ret = -ENOMEM;
3518		goto fail_put;
3519	}
3520
3521	build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
3522	txmsg->dst = mstb;
3523
3524	drm_dp_queue_down_tx(mgr, txmsg);
3525
3526	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3527	if (ret > 0) {
3528		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3529			ret = -EIO;
3530		else
3531			ret = size;
3532	}
3533
3534	kfree(txmsg);
3535fail_put:
3536	drm_dp_mst_topology_put_mstb(mstb);
3537	return ret;
3538}
3539
3540static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
3541{
3542	struct drm_dp_sideband_msg_reply_body reply;
3543
3544	reply.reply_type = DP_SIDEBAND_REPLY_ACK;
3545	reply.req_type = req_type;
3546	drm_dp_encode_sideband_reply(&reply, msg);
3547	return 0;
3548}
3549
3550static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
3551				    struct drm_dp_mst_branch *mstb,
3552				    int req_type, bool broadcast)
3553{
3554	struct drm_dp_sideband_msg_tx *txmsg;
3555
3556	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3557	if (!txmsg)
3558		return -ENOMEM;
3559
3560	txmsg->dst = mstb;
3561	drm_dp_encode_up_ack_reply(txmsg, req_type);
3562
3563	mutex_lock(&mgr->qlock);
3564	/* construct a chunk from the first msg in the tx_msg queue */
3565	process_single_tx_qlock(mgr, txmsg, true);
3566	mutex_unlock(&mgr->qlock);
3567
3568	kfree(txmsg);
3569	return 0;
3570}
3571
3572/**
3573 * drm_dp_get_vc_payload_bw - get the VC payload BW for an MST link
3574 * @mgr: The &drm_dp_mst_topology_mgr to use
3575 * @link_rate: link rate in 10kbits/s units
3576 * @link_lane_count: lane count
3577 *
3578 * Calculate the total bandwidth of a MultiStream Transport link. The returned
3579 * value is in units of PBNs/(timeslots/1 MTP). This value can be used to
3580 * convert the number of PBNs required for a given stream to the number of
3581 * timeslots this stream requires in each MTP.
3582 *
3583 * Returns the BW / timeslot value in 20.12 fixed point format.
3584 */
3585fixed20_12 drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr,
3586				    int link_rate, int link_lane_count)
3587{
3588	int ch_coding_efficiency =
3589		drm_dp_bw_channel_coding_efficiency(drm_dp_is_uhbr_rate(link_rate));
3590	fixed20_12 ret;
3591
3592	if (link_rate == 0 || link_lane_count == 0)
3593		drm_dbg_kms(mgr->dev, "invalid link rate/lane count: (%d / %d)\n",
3594			    link_rate, link_lane_count);
3595
3596	/* See DP v2.0 2.6.4.2, 2.7.6.3 VCPayload_Bandwidth_for_OneTimeSlotPer_MTP_Allocation */
3597	ret.full = DIV_ROUND_DOWN_ULL(mul_u32_u32(link_rate * link_lane_count,
3598						  ch_coding_efficiency),
3599				      (1000000ULL * 8 * 5400) >> 12);
3600
3601	return ret;
3602}
3603EXPORT_SYMBOL(drm_dp_get_vc_payload_bw);
3604
3605/**
3606 * drm_dp_read_mst_cap() - check whether or not a sink supports MST
3607 * @aux: The DP AUX channel to use
3608 * @dpcd: A cached copy of the DPCD capabilities for this sink
3609 *
3610 * Returns: %True if the sink supports MST, %false otherwise
3611 */
3612bool drm_dp_read_mst_cap(struct drm_dp_aux *aux,
3613			 const u8 dpcd[DP_RECEIVER_CAP_SIZE])
3614{
3615	u8 mstm_cap;
3616
3617	if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12)
3618		return false;
3619
3620	if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, &mstm_cap) != 1)
3621		return false;
3622
3623	return mstm_cap & DP_MST_CAP;
3624}
3625EXPORT_SYMBOL(drm_dp_read_mst_cap);
3626
3627/**
3628 * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
3629 * @mgr: manager to set state for
3630 * @mst_state: true to enable MST on this connector - false to disable.
3631 *
3632 * This is called by the driver when it detects an MST capable device plugged
3633 * into a DP MST capable port, or when a DP MST capable device is unplugged.
3634 */
3635int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
3636{
3637	int ret = 0;
3638	struct drm_dp_mst_branch *mstb = NULL;
3639
3640	mutex_lock(&mgr->lock);
3641	if (mst_state == mgr->mst_state)
3642		goto out_unlock;
3643
3644	mgr->mst_state = mst_state;
3645	/* set the device into MST mode */
3646	if (mst_state) {
3647		WARN_ON(mgr->mst_primary);
3648
3649		/* get dpcd info */
3650		ret = drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd);
3651		if (ret < 0) {
3652			drm_dbg_kms(mgr->dev, "%s: failed to read DPCD, ret %d\n",
3653				    mgr->aux->name, ret);
3654			goto out_unlock;
3655		}
3656
3657		/* add initial branch device at LCT 1 */
3658		mstb = drm_dp_add_mst_branch_device(1, NULL);
3659		if (mstb == NULL) {
3660			ret = -ENOMEM;
3661			goto out_unlock;
3662		}
3663		mstb->mgr = mgr;
3664
3665		/* give this the main reference */
3666		mgr->mst_primary = mstb;
3667		drm_dp_mst_topology_get_mstb(mgr->mst_primary);
3668
3669		ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3670					 DP_MST_EN |
3671					 DP_UP_REQ_EN |
3672					 DP_UPSTREAM_IS_SRC);
3673		if (ret < 0)
3674			goto out_unlock;
3675
3676		/* Write reset payload */
3677		drm_dp_dpcd_write_payload(mgr, 0, 0, 0x3f);
3678
3679		queue_work(system_long_wq, &mgr->work);
3680
3681		ret = 0;
3682	} else {
3683		/* disable MST on the device */
3684		mstb = mgr->mst_primary;
3685		mgr->mst_primary = NULL;
3686		/* this can fail if the device is gone */
3687		drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
3688		ret = 0;
3689		mgr->payload_id_table_cleared = false;
3690
3691		memset(&mgr->down_rep_recv, 0, sizeof(mgr->down_rep_recv));
3692		memset(&mgr->up_req_recv, 0, sizeof(mgr->up_req_recv));
3693	}
3694
3695out_unlock:
3696	mutex_unlock(&mgr->lock);
3697	if (mstb)
3698		drm_dp_mst_topology_put_mstb(mstb);
3699	return ret;
3700
3701}
3702EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
3703
3704static void
3705drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch *mstb)
3706{
3707	struct drm_dp_mst_port *port;
3708
3709	/* The link address will need to be re-sent on resume */
3710	mstb->link_address_sent = false;
3711
3712	list_for_each_entry(port, &mstb->ports, next)
3713		if (port->mstb)
3714			drm_dp_mst_topology_mgr_invalidate_mstb(port->mstb);
3715}
3716
3717/**
3718 * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
3719 * @mgr: manager to suspend
3720 *
3721 * This function tells the MST device that we can't handle UP messages
3722 * anymore. This should stop it from sending any since we are suspended.
3723 */
3724void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
3725{
3726	mutex_lock(&mgr->lock);
3727	drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3728			   DP_MST_EN | DP_UPSTREAM_IS_SRC);
3729	mutex_unlock(&mgr->lock);
3730	flush_work(&mgr->up_req_work);
3731	flush_work(&mgr->work);
3732	flush_work(&mgr->delayed_destroy_work);
3733
3734	mutex_lock(&mgr->lock);
3735	if (mgr->mst_state && mgr->mst_primary)
3736		drm_dp_mst_topology_mgr_invalidate_mstb(mgr->mst_primary);
3737	mutex_unlock(&mgr->lock);
3738}
3739EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
3740
3741/**
3742 * drm_dp_mst_topology_mgr_resume() - resume the MST manager
3743 * @mgr: manager to resume
3744 * @sync: whether or not to perform topology reprobing synchronously
3745 *
3746 * This will fetch DPCD and see if the device is still there,
3747 * if it is, it will rewrite the MSTM control bits, and return.
3748 *
3749 * If the device fails this returns -1, and the driver should do
3750 * a full MST reprobe, in case we were undocked.
3751 *
3752 * During system resume (where it is assumed that the driver will be calling
3753 * drm_atomic_helper_resume()) this function should be called beforehand with
3754 * @sync set to true. In contexts like runtime resume where the driver is not
3755 * expected to be calling drm_atomic_helper_resume(), this function should be
3756 * called with @sync set to false in order to avoid deadlocking.
3757 *
3758 * Returns: -1 if the MST topology was removed while we were suspended, 0
3759 * otherwise.
3760 */
3761int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
3762				   bool sync)
3763{
3764	int ret;
3765	u8 guid[16];
3766
3767	mutex_lock(&mgr->lock);
3768	if (!mgr->mst_primary)
3769		goto out_fail;
3770
3771	if (drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd) < 0) {
3772		drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3773		goto out_fail;
3774	}
3775
3776	ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3777				 DP_MST_EN |
3778				 DP_UP_REQ_EN |
3779				 DP_UPSTREAM_IS_SRC);
3780	if (ret < 0) {
3781		drm_dbg_kms(mgr->dev, "mst write failed - undocked during suspend?\n");
3782		goto out_fail;
3783	}
3784
3785	/* Some hubs forget their guids after they resume */
3786	ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
3787	if (ret != 16) {
3788		drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3789		goto out_fail;
3790	}
3791
3792	ret = drm_dp_check_mstb_guid(mgr->mst_primary, guid);
3793	if (ret) {
3794		drm_dbg_kms(mgr->dev, "check mstb failed - undocked during suspend?\n");
3795		goto out_fail;
3796	}
3797
3798	/*
3799	 * For the final step of resuming the topology, we need to bring the
3800	 * state of our in-memory topology back into sync with reality. So,
3801	 * restart the probing process as if we're probing a new hub
3802	 */
3803	queue_work(system_long_wq, &mgr->work);
3804	mutex_unlock(&mgr->lock);
3805
3806	if (sync) {
3807		drm_dbg_kms(mgr->dev,
3808			    "Waiting for link probe work to finish re-syncing topology...\n");
3809		flush_work(&mgr->work);
3810	}
3811
3812	return 0;
3813
3814out_fail:
3815	mutex_unlock(&mgr->lock);
3816	return -1;
3817}
3818EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
3819
3820static bool
3821drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up,
3822		      struct drm_dp_mst_branch **mstb)
3823{
3824	int len;
3825	u8 replyblock[32];
3826	int replylen, curreply;
3827	int ret;
3828	u8 hdrlen;
3829	struct drm_dp_sideband_msg_hdr hdr;
3830	struct drm_dp_sideband_msg_rx *msg =
3831		up ? &mgr->up_req_recv : &mgr->down_rep_recv;
3832	int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE :
3833			   DP_SIDEBAND_MSG_DOWN_REP_BASE;
3834
3835	if (!up)
3836		*mstb = NULL;
3837
3838	len = min(mgr->max_dpcd_transaction_bytes, 16);
3839	ret = drm_dp_dpcd_read(mgr->aux, basereg, replyblock, len);
3840	if (ret != len) {
3841		drm_dbg_kms(mgr->dev, "failed to read DPCD down rep %d %d\n", len, ret);
3842		return false;
3843	}
3844
3845	ret = drm_dp_decode_sideband_msg_hdr(mgr, &hdr, replyblock, len, &hdrlen);
3846	if (ret == false) {
3847		print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16,
3848			       1, replyblock, len, false);
3849		drm_dbg_kms(mgr->dev, "ERROR: failed header\n");
3850		return false;
3851	}
3852
3853	if (!up) {
3854		/* Caller is responsible for giving back this reference */
3855		*mstb = drm_dp_get_mst_branch_device(mgr, hdr.lct, hdr.rad);
3856		if (!*mstb) {
3857			drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr.lct);
3858			return false;
3859		}
3860	}
3861
3862	if (!drm_dp_sideband_msg_set_header(msg, &hdr, hdrlen)) {
3863		drm_dbg_kms(mgr->dev, "sideband msg set header failed %d\n", replyblock[0]);
3864		return false;
3865	}
3866
3867	replylen = min(msg->curchunk_len, (u8)(len - hdrlen));
3868	ret = drm_dp_sideband_append_payload(msg, replyblock + hdrlen, replylen);
3869	if (!ret) {
3870		drm_dbg_kms(mgr->dev, "sideband msg build failed %d\n", replyblock[0]);
3871		return false;
3872	}
3873
3874	replylen = msg->curchunk_len + msg->curchunk_hdrlen - len;
3875	curreply = len;
3876	while (replylen > 0) {
3877		len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
3878		ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
3879				    replyblock, len);
3880		if (ret != len) {
3881			drm_dbg_kms(mgr->dev, "failed to read a chunk (len %d, ret %d)\n",
3882				    len, ret);
3883			return false;
3884		}
3885
3886		ret = drm_dp_sideband_append_payload(msg, replyblock, len);
3887		if (!ret) {
3888			drm_dbg_kms(mgr->dev, "failed to build sideband msg\n");
3889			return false;
3890		}
3891
3892		curreply += len;
3893		replylen -= len;
3894	}
3895	return true;
3896}
3897
3898static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
3899{
3900	struct drm_dp_sideband_msg_tx *txmsg;
3901	struct drm_dp_mst_branch *mstb = NULL;
3902	struct drm_dp_sideband_msg_rx *msg = &mgr->down_rep_recv;
3903
3904	if (!drm_dp_get_one_sb_msg(mgr, false, &mstb))
3905		goto out_clear_reply;
3906
3907	/* Multi-packet message transmission, don't clear the reply */
3908	if (!msg->have_eomt)
3909		goto out;
3910
3911	/* find the message */
3912	mutex_lock(&mgr->qlock);
3913	txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
3914					 struct drm_dp_sideband_msg_tx, next);
3915	mutex_unlock(&mgr->qlock);
3916
3917	/* Were we actually expecting a response, and from this mstb? */
3918	if (!txmsg || txmsg->dst != mstb) {
3919		struct drm_dp_sideband_msg_hdr *hdr;
3920
3921		hdr = &msg->initial_hdr;
3922		drm_dbg_kms(mgr->dev, "Got MST reply with no msg %p %d %d %02x %02x\n",
3923			    mstb, hdr->seqno, hdr->lct, hdr->rad[0], msg->msg[0]);
3924		goto out_clear_reply;
3925	}
3926
3927	drm_dp_sideband_parse_reply(mgr, msg, &txmsg->reply);
3928
3929	if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3930		drm_dbg_kms(mgr->dev,
3931			    "Got NAK reply: req 0x%02x (%s), reason 0x%02x (%s), nak data 0x%02x\n",
3932			    txmsg->reply.req_type,
3933			    drm_dp_mst_req_type_str(txmsg->reply.req_type),
3934			    txmsg->reply.u.nak.reason,
3935			    drm_dp_mst_nak_reason_str(txmsg->reply.u.nak.reason),
3936			    txmsg->reply.u.nak.nak_data);
3937	}
3938
3939	memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
3940	drm_dp_mst_topology_put_mstb(mstb);
3941
3942	mutex_lock(&mgr->qlock);
3943	txmsg->state = DRM_DP_SIDEBAND_TX_RX;
3944	list_del(&txmsg->next);
3945	mutex_unlock(&mgr->qlock);
3946
3947	wake_up_all(&mgr->tx_waitq);
3948
3949	return 0;
3950
3951out_clear_reply:
3952	memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
3953out:
3954	if (mstb)
3955		drm_dp_mst_topology_put_mstb(mstb);
3956
3957	return 0;
3958}
3959
3960static inline bool
3961drm_dp_mst_process_up_req(struct drm_dp_mst_topology_mgr *mgr,
3962			  struct drm_dp_pending_up_req *up_req)
3963{
3964	struct drm_dp_mst_branch *mstb = NULL;
3965	struct drm_dp_sideband_msg_req_body *msg = &up_req->msg;
3966	struct drm_dp_sideband_msg_hdr *hdr = &up_req->hdr;
3967	bool hotplug = false, dowork = false;
3968
3969	if (hdr->broadcast) {
3970		const u8 *guid = NULL;
3971
3972		if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY)
3973			guid = msg->u.conn_stat.guid;
3974		else if (msg->req_type == DP_RESOURCE_STATUS_NOTIFY)
3975			guid = msg->u.resource_stat.guid;
3976
3977		if (guid)
3978			mstb = drm_dp_get_mst_branch_device_by_guid(mgr, guid);
3979	} else {
3980		mstb = drm_dp_get_mst_branch_device(mgr, hdr->lct, hdr->rad);
3981	}
3982
3983	if (!mstb) {
3984		drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr->lct);
3985		return false;
3986	}
3987
3988	/* TODO: Add missing handler for DP_RESOURCE_STATUS_NOTIFY events */
3989	if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY) {
3990		dowork = drm_dp_mst_handle_conn_stat(mstb, &msg->u.conn_stat);
3991		hotplug = true;
3992	}
3993
3994	drm_dp_mst_topology_put_mstb(mstb);
3995
3996	if (dowork)
3997		queue_work(system_long_wq, &mgr->work);
3998	return hotplug;
3999}
4000
4001static void drm_dp_mst_up_req_work(struct work_struct *work)
4002{
4003	struct drm_dp_mst_topology_mgr *mgr =
4004		container_of(work, struct drm_dp_mst_topology_mgr,
4005			     up_req_work);
4006	struct drm_dp_pending_up_req *up_req;
4007	bool send_hotplug = false;
4008
4009	mutex_lock(&mgr->probe_lock);
4010	while (true) {
4011		mutex_lock(&mgr->up_req_lock);
4012		up_req = list_first_entry_or_null(&mgr->up_req_list,
4013						  struct drm_dp_pending_up_req,
4014						  next);
4015		if (up_req)
4016			list_del(&up_req->next);
4017		mutex_unlock(&mgr->up_req_lock);
4018
4019		if (!up_req)
4020			break;
4021
4022		send_hotplug |= drm_dp_mst_process_up_req(mgr, up_req);
4023		kfree(up_req);
4024	}
4025	mutex_unlock(&mgr->probe_lock);
4026
4027	if (send_hotplug)
4028		drm_kms_helper_hotplug_event(mgr->dev);
4029}
4030
4031static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
4032{
4033	struct drm_dp_pending_up_req *up_req;
4034
4035	if (!drm_dp_get_one_sb_msg(mgr, true, NULL))
4036		goto out;
4037
4038	if (!mgr->up_req_recv.have_eomt)
4039		return 0;
4040
4041	up_req = kzalloc(sizeof(*up_req), GFP_KERNEL);
4042	if (!up_req)
4043		return -ENOMEM;
4044
4045	INIT_LIST_HEAD(&up_req->next);
4046
4047	drm_dp_sideband_parse_req(mgr, &mgr->up_req_recv, &up_req->msg);
4048
4049	if (up_req->msg.req_type != DP_CONNECTION_STATUS_NOTIFY &&
4050	    up_req->msg.req_type != DP_RESOURCE_STATUS_NOTIFY) {
4051		drm_dbg_kms(mgr->dev, "Received unknown up req type, ignoring: %x\n",
4052			    up_req->msg.req_type);
4053		kfree(up_req);
4054		goto out;
4055	}
4056
4057	drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, up_req->msg.req_type,
4058				 false);
4059
4060	if (up_req->msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
4061		const struct drm_dp_connection_status_notify *conn_stat =
4062			&up_req->msg.u.conn_stat;
4063
4064		drm_dbg_kms(mgr->dev, "Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n",
4065			    conn_stat->port_number,
4066			    conn_stat->legacy_device_plug_status,
4067			    conn_stat->displayport_device_plug_status,
4068			    conn_stat->message_capability_status,
4069			    conn_stat->input_port,
4070			    conn_stat->peer_device_type);
4071	} else if (up_req->msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
4072		const struct drm_dp_resource_status_notify *res_stat =
4073			&up_req->msg.u.resource_stat;
4074
4075		drm_dbg_kms(mgr->dev, "Got RSN: pn: %d avail_pbn %d\n",
4076			    res_stat->port_number,
4077			    res_stat->available_pbn);
4078	}
4079
4080	up_req->hdr = mgr->up_req_recv.initial_hdr;
4081	mutex_lock(&mgr->up_req_lock);
4082	list_add_tail(&up_req->next, &mgr->up_req_list);
4083	mutex_unlock(&mgr->up_req_lock);
4084	queue_work(system_long_wq, &mgr->up_req_work);
4085
4086out:
4087	memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
4088	return 0;
4089}
4090
4091/**
4092 * drm_dp_mst_hpd_irq_handle_event() - MST hotplug IRQ handle MST event
4093 * @mgr: manager to notify irq for.
4094 * @esi: 4 bytes from SINK_COUNT_ESI
4095 * @ack: 4 bytes used to ack events starting from SINK_COUNT_ESI
4096 * @handled: whether the hpd interrupt was consumed or not
4097 *
4098 * This should be called from the driver when it detects a HPD IRQ,
4099 * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
4100 * topology manager will process the sideband messages received
4101 * as indicated in the DEVICE_SERVICE_IRQ_VECTOR_ESI0 and set the
4102 * corresponding flags that Driver has to ack the DP receiver later.
4103 *
4104 * Note that driver shall also call
4105 * drm_dp_mst_hpd_irq_send_new_request() if the 'handled' is set
4106 * after calling this function, to try to kick off a new request in
4107 * the queue if the previous message transaction is completed.
4108 *
4109 * See also:
4110 * drm_dp_mst_hpd_irq_send_new_request()
4111 */
4112int drm_dp_mst_hpd_irq_handle_event(struct drm_dp_mst_topology_mgr *mgr, const u8 *esi,
4113				    u8 *ack, bool *handled)
4114{
4115	int ret = 0;
4116	int sc;
4117	*handled = false;
4118	sc = DP_GET_SINK_COUNT(esi[0]);
4119
4120	if (sc != mgr->sink_count) {
4121		mgr->sink_count = sc;
4122		*handled = true;
4123	}
4124
4125	if (esi[1] & DP_DOWN_REP_MSG_RDY) {
4126		ret = drm_dp_mst_handle_down_rep(mgr);
4127		*handled = true;
4128		ack[1] |= DP_DOWN_REP_MSG_RDY;
4129	}
4130
4131	if (esi[1] & DP_UP_REQ_MSG_RDY) {
4132		ret |= drm_dp_mst_handle_up_req(mgr);
4133		*handled = true;
4134		ack[1] |= DP_UP_REQ_MSG_RDY;
4135	}
4136
4137	return ret;
4138}
4139EXPORT_SYMBOL(drm_dp_mst_hpd_irq_handle_event);
4140
4141/**
4142 * drm_dp_mst_hpd_irq_send_new_request() - MST hotplug IRQ kick off new request
4143 * @mgr: manager to notify irq for.
4144 *
4145 * This should be called from the driver when mst irq event is handled
4146 * and acked. Note that new down request should only be sent when
4147 * previous message transaction is completed. Source is not supposed to generate
4148 * interleaved message transactions.
4149 */
4150void drm_dp_mst_hpd_irq_send_new_request(struct drm_dp_mst_topology_mgr *mgr)
4151{
4152	struct drm_dp_sideband_msg_tx *txmsg;
4153	bool kick = true;
4154
4155	mutex_lock(&mgr->qlock);
4156	txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
4157					 struct drm_dp_sideband_msg_tx, next);
4158	/* If last transaction is not completed yet*/
4159	if (!txmsg ||
4160	    txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
4161	    txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
4162		kick = false;
4163	mutex_unlock(&mgr->qlock);
4164
4165	if (kick)
4166		drm_dp_mst_kick_tx(mgr);
4167}
4168EXPORT_SYMBOL(drm_dp_mst_hpd_irq_send_new_request);
4169/**
4170 * drm_dp_mst_detect_port() - get connection status for an MST port
4171 * @connector: DRM connector for this port
4172 * @ctx: The acquisition context to use for grabbing locks
4173 * @mgr: manager for this port
4174 * @port: pointer to a port
4175 *
4176 * This returns the current connection state for a port.
4177 */
4178int
4179drm_dp_mst_detect_port(struct drm_connector *connector,
4180		       struct drm_modeset_acquire_ctx *ctx,
4181		       struct drm_dp_mst_topology_mgr *mgr,
4182		       struct drm_dp_mst_port *port)
4183{
4184	int ret;
4185
4186	/* we need to search for the port in the mgr in case it's gone */
4187	port = drm_dp_mst_topology_get_port_validated(mgr, port);
4188	if (!port)
4189		return connector_status_disconnected;
4190
4191	ret = drm_modeset_lock(&mgr->base.lock, ctx);
4192	if (ret)
4193		goto out;
4194
4195	ret = connector_status_disconnected;
4196
4197	if (!port->ddps)
4198		goto out;
4199
4200	switch (port->pdt) {
4201	case DP_PEER_DEVICE_NONE:
4202		break;
4203	case DP_PEER_DEVICE_MST_BRANCHING:
4204		if (!port->mcs)
4205			ret = connector_status_connected;
4206		break;
4207
4208	case DP_PEER_DEVICE_SST_SINK:
4209		ret = connector_status_connected;
4210		/* for logical ports - cache the EDID */
4211		if (port->port_num >= DP_MST_LOGICAL_PORT_0 && !port->cached_edid)
4212			port->cached_edid = drm_edid_read_ddc(connector, &port->aux.ddc);
4213		break;
4214	case DP_PEER_DEVICE_DP_LEGACY_CONV:
4215		if (port->ldps)
4216			ret = connector_status_connected;
4217		break;
4218	}
4219out:
4220	drm_dp_mst_topology_put_port(port);
4221	return ret;
4222}
4223EXPORT_SYMBOL(drm_dp_mst_detect_port);
4224
4225/**
4226 * drm_dp_mst_edid_read() - get EDID for an MST port
4227 * @connector: toplevel connector to get EDID for
4228 * @mgr: manager for this port
4229 * @port: unverified pointer to a port.
4230 *
4231 * This returns an EDID for the port connected to a connector,
4232 * It validates the pointer still exists so the caller doesn't require a
4233 * reference.
4234 */
4235const struct drm_edid *drm_dp_mst_edid_read(struct drm_connector *connector,
4236					    struct drm_dp_mst_topology_mgr *mgr,
4237					    struct drm_dp_mst_port *port)
4238{
4239	const struct drm_edid *drm_edid;
4240
4241	/* we need to search for the port in the mgr in case it's gone */
4242	port = drm_dp_mst_topology_get_port_validated(mgr, port);
4243	if (!port)
4244		return NULL;
4245
4246	if (port->cached_edid)
4247		drm_edid = drm_edid_dup(port->cached_edid);
4248	else
4249		drm_edid = drm_edid_read_ddc(connector, &port->aux.ddc);
4250
4251	drm_dp_mst_topology_put_port(port);
4252
4253	return drm_edid;
4254}
4255EXPORT_SYMBOL(drm_dp_mst_edid_read);
4256
4257/**
4258 * drm_dp_mst_get_edid() - get EDID for an MST port
4259 * @connector: toplevel connector to get EDID for
4260 * @mgr: manager for this port
4261 * @port: unverified pointer to a port.
4262 *
4263 * This function is deprecated; please use drm_dp_mst_edid_read() instead.
4264 *
4265 * This returns an EDID for the port connected to a connector,
4266 * It validates the pointer still exists so the caller doesn't require a
4267 * reference.
4268 */
4269struct edid *drm_dp_mst_get_edid(struct drm_connector *connector,
4270				 struct drm_dp_mst_topology_mgr *mgr,
4271				 struct drm_dp_mst_port *port)
4272{
4273	const struct drm_edid *drm_edid;
4274	struct edid *edid;
4275
4276	drm_edid = drm_dp_mst_edid_read(connector, mgr, port);
4277
4278	edid = drm_edid_duplicate(drm_edid_raw(drm_edid));
4279
4280	drm_edid_free(drm_edid);
4281
4282	return edid;
4283}
4284EXPORT_SYMBOL(drm_dp_mst_get_edid);
4285
4286/**
4287 * drm_dp_atomic_find_time_slots() - Find and add time slots to the state
4288 * @state: global atomic state
4289 * @mgr: MST topology manager for the port
4290 * @port: port to find time slots for
4291 * @pbn: bandwidth required for the mode in PBN
4292 *
4293 * Allocates time slots to @port, replacing any previous time slot allocations it may
4294 * have had. Any atomic drivers which support MST must call this function in
4295 * their &drm_encoder_helper_funcs.atomic_check() callback unconditionally to
4296 * change the current time slot allocation for the new state, and ensure the MST
4297 * atomic state is added whenever the state of payloads in the topology changes.
4298 *
4299 * Allocations set by this function are not checked against the bandwidth
4300 * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
4301 *
4302 * Additionally, it is OK to call this function multiple times on the same
4303 * @port as needed. It is not OK however, to call this function and
4304 * drm_dp_atomic_release_time_slots() in the same atomic check phase.
4305 *
4306 * See also:
4307 * drm_dp_atomic_release_time_slots()
4308 * drm_dp_mst_atomic_check()
4309 *
4310 * Returns:
4311 * Total slots in the atomic state assigned for this port, or a negative error
4312 * code if the port no longer exists
4313 */
4314int drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,
4315				  struct drm_dp_mst_topology_mgr *mgr,
4316				  struct drm_dp_mst_port *port, int pbn)
4317{
4318	struct drm_dp_mst_topology_state *topology_state;
4319	struct drm_dp_mst_atomic_payload *payload = NULL;
4320	struct drm_connector_state *conn_state;
4321	int prev_slots = 0, prev_bw = 0, req_slots;
4322
4323	topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4324	if (IS_ERR(topology_state))
4325		return PTR_ERR(topology_state);
4326
4327	conn_state = drm_atomic_get_new_connector_state(state, port->connector);
4328	topology_state->pending_crtc_mask |= drm_crtc_mask(conn_state->crtc);
4329
4330	/* Find the current allocation for this port, if any */
4331	payload = drm_atomic_get_mst_payload_state(topology_state, port);
4332	if (payload) {
4333		prev_slots = payload->time_slots;
4334		prev_bw = payload->pbn;
4335
4336		/*
4337		 * This should never happen, unless the driver tries
4338		 * releasing and allocating the same timeslot allocation,
4339		 * which is an error
4340		 */
4341		if (drm_WARN_ON(mgr->dev, payload->delete)) {
4342			drm_err(mgr->dev,
4343				"cannot allocate and release time slots on [MST PORT:%p] in the same state\n",
4344				port);
4345			return -EINVAL;
4346		}
4347	}
4348
4349	req_slots = DIV_ROUND_UP(dfixed_const(pbn), topology_state->pbn_div.full);
4350
4351	drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] TU %d -> %d\n",
4352		       port->connector->base.id, port->connector->name,
4353		       port, prev_slots, req_slots);
4354	drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] PBN %d -> %d\n",
4355		       port->connector->base.id, port->connector->name,
4356		       port, prev_bw, pbn);
4357
4358	/* Add the new allocation to the state, note the VCPI isn't assigned until the end */
4359	if (!payload) {
4360		payload = kzalloc(sizeof(*payload), GFP_KERNEL);
4361		if (!payload)
4362			return -ENOMEM;
4363
4364		drm_dp_mst_get_port_malloc(port);
4365		payload->port = port;
4366		payload->vc_start_slot = -1;
4367		payload->payload_allocation_status = DRM_DP_MST_PAYLOAD_ALLOCATION_NONE;
4368		list_add(&payload->next, &topology_state->payloads);
4369	}
4370	payload->time_slots = req_slots;
4371	payload->pbn = pbn;
4372
4373	return req_slots;
4374}
4375EXPORT_SYMBOL(drm_dp_atomic_find_time_slots);
4376
4377/**
4378 * drm_dp_atomic_release_time_slots() - Release allocated time slots
4379 * @state: global atomic state
4380 * @mgr: MST topology manager for the port
4381 * @port: The port to release the time slots from
4382 *
4383 * Releases any time slots that have been allocated to a port in the atomic
4384 * state. Any atomic drivers which support MST must call this function
4385 * unconditionally in their &drm_connector_helper_funcs.atomic_check() callback.
4386 * This helper will check whether time slots would be released by the new state and
4387 * respond accordingly, along with ensuring the MST state is always added to the
4388 * atomic state whenever a new state would modify the state of payloads on the
4389 * topology.
4390 *
4391 * It is OK to call this even if @port has been removed from the system.
4392 * Additionally, it is OK to call this function multiple times on the same
4393 * @port as needed. It is not OK however, to call this function and
4394 * drm_dp_atomic_find_time_slots() on the same @port in a single atomic check
4395 * phase.
4396 *
4397 * See also:
4398 * drm_dp_atomic_find_time_slots()
4399 * drm_dp_mst_atomic_check()
4400 *
4401 * Returns:
4402 * 0 on success, negative error code otherwise
4403 */
4404int drm_dp_atomic_release_time_slots(struct drm_atomic_state *state,
4405				     struct drm_dp_mst_topology_mgr *mgr,
4406				     struct drm_dp_mst_port *port)
4407{
4408	struct drm_dp_mst_topology_state *topology_state;
4409	struct drm_dp_mst_atomic_payload *payload;
4410	struct drm_connector_state *old_conn_state, *new_conn_state;
4411	bool update_payload = true;
4412
4413	old_conn_state = drm_atomic_get_old_connector_state(state, port->connector);
4414	if (!old_conn_state->crtc)
4415		return 0;
4416
4417	/* If the CRTC isn't disabled by this state, don't release it's payload */
4418	new_conn_state = drm_atomic_get_new_connector_state(state, port->connector);
4419	if (new_conn_state->crtc) {
4420		struct drm_crtc_state *crtc_state =
4421			drm_atomic_get_new_crtc_state(state, new_conn_state->crtc);
4422
4423		/* No modeset means no payload changes, so it's safe to not pull in the MST state */
4424		if (!crtc_state || !drm_atomic_crtc_needs_modeset(crtc_state))
4425			return 0;
4426
4427		if (!crtc_state->mode_changed && !crtc_state->connectors_changed)
4428			update_payload = false;
4429	}
4430
4431	topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4432	if (IS_ERR(topology_state))
4433		return PTR_ERR(topology_state);
4434
4435	topology_state->pending_crtc_mask |= drm_crtc_mask(old_conn_state->crtc);
4436	if (!update_payload)
4437		return 0;
4438
4439	payload = drm_atomic_get_mst_payload_state(topology_state, port);
4440	if (WARN_ON(!payload)) {
4441		drm_err(mgr->dev, "No payload for [MST PORT:%p] found in mst state %p\n",
4442			port, &topology_state->base);
4443		return -EINVAL;
4444	}
4445
4446	if (new_conn_state->crtc)
4447		return 0;
4448
4449	drm_dbg_atomic(mgr->dev, "[MST PORT:%p] TU %d -> 0\n", port, payload->time_slots);
4450	if (!payload->delete) {
4451		payload->pbn = 0;
4452		payload->delete = true;
4453		topology_state->payload_mask &= ~BIT(payload->vcpi - 1);
4454	}
4455
4456	return 0;
4457}
4458EXPORT_SYMBOL(drm_dp_atomic_release_time_slots);
4459
4460/**
4461 * drm_dp_mst_atomic_setup_commit() - setup_commit hook for MST helpers
4462 * @state: global atomic state
4463 *
4464 * This function saves all of the &drm_crtc_commit structs in an atomic state that touch any CRTCs
4465 * currently assigned to an MST topology. Drivers must call this hook from their
4466 * &drm_mode_config_helper_funcs.atomic_commit_setup hook.
4467 *
4468 * Returns:
4469 * 0 if all CRTC commits were retrieved successfully, negative error code otherwise
4470 */
4471int drm_dp_mst_atomic_setup_commit(struct drm_atomic_state *state)
4472{
4473	struct drm_dp_mst_topology_mgr *mgr;
4474	struct drm_dp_mst_topology_state *mst_state;
4475	struct drm_crtc *crtc;
4476	struct drm_crtc_state *crtc_state;
4477	int i, j, commit_idx, num_commit_deps;
4478
4479	for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
4480		if (!mst_state->pending_crtc_mask)
4481			continue;
4482
4483		num_commit_deps = hweight32(mst_state->pending_crtc_mask);
4484		mst_state->commit_deps = kmalloc_array(num_commit_deps,
4485						       sizeof(*mst_state->commit_deps), GFP_KERNEL);
4486		if (!mst_state->commit_deps)
4487			return -ENOMEM;
4488		mst_state->num_commit_deps = num_commit_deps;
4489
4490		commit_idx = 0;
4491		for_each_new_crtc_in_state(state, crtc, crtc_state, j) {
4492			if (mst_state->pending_crtc_mask & drm_crtc_mask(crtc)) {
4493				mst_state->commit_deps[commit_idx++] =
4494					drm_crtc_commit_get(crtc_state->commit);
4495			}
4496		}
4497	}
4498
4499	return 0;
4500}
4501EXPORT_SYMBOL(drm_dp_mst_atomic_setup_commit);
4502
4503/**
4504 * drm_dp_mst_atomic_wait_for_dependencies() - Wait for all pending commits on MST topologies,
4505 * prepare new MST state for commit
4506 * @state: global atomic state
4507 *
4508 * Goes through any MST topologies in this atomic state, and waits for any pending commits which
4509 * touched CRTCs that were/are on an MST topology to be programmed to hardware and flipped to before
4510 * returning. This is to prevent multiple non-blocking commits affecting an MST topology from racing
4511 * with eachother by forcing them to be executed sequentially in situations where the only resources
4512 * the modeset objects in these commits share are an MST topology.
4513 *
4514 * This function also prepares the new MST state for commit by performing some state preparation
4515 * which can't be done until this point, such as reading back the final VC start slots (which are
4516 * determined at commit-time) from the previous state.
4517 *
4518 * All MST drivers must call this function after calling drm_atomic_helper_wait_for_dependencies(),
4519 * or whatever their equivalent of that is.
4520 */
4521void drm_dp_mst_atomic_wait_for_dependencies(struct drm_atomic_state *state)
4522{
4523	struct drm_dp_mst_topology_state *old_mst_state, *new_mst_state;
4524	struct drm_dp_mst_topology_mgr *mgr;
4525	struct drm_dp_mst_atomic_payload *old_payload, *new_payload;
4526	int i, j, ret;
4527
4528	for_each_oldnew_mst_mgr_in_state(state, mgr, old_mst_state, new_mst_state, i) {
4529		for (j = 0; j < old_mst_state->num_commit_deps; j++) {
4530			ret = drm_crtc_commit_wait(old_mst_state->commit_deps[j]);
4531			if (ret < 0)
4532				drm_err(state->dev, "Failed to wait for %s: %d\n",
4533					old_mst_state->commit_deps[j]->crtc->name, ret);
4534		}
4535
4536		/* Now that previous state is committed, it's safe to copy over the start slot
4537		 * and allocation status assignments
4538		 */
4539		list_for_each_entry(old_payload, &old_mst_state->payloads, next) {
4540			if (old_payload->delete)
4541				continue;
4542
4543			new_payload = drm_atomic_get_mst_payload_state(new_mst_state,
4544								       old_payload->port);
4545			new_payload->vc_start_slot = old_payload->vc_start_slot;
4546			new_payload->payload_allocation_status =
4547							old_payload->payload_allocation_status;
4548		}
4549	}
4550}
4551EXPORT_SYMBOL(drm_dp_mst_atomic_wait_for_dependencies);
4552
4553/**
4554 * drm_dp_mst_root_conn_atomic_check() - Serialize CRTC commits on MST-capable connectors operating
4555 * in SST mode
4556 * @new_conn_state: The new connector state of the &drm_connector
4557 * @mgr: The MST topology manager for the &drm_connector
4558 *
4559 * Since MST uses fake &drm_encoder structs, the generic atomic modesetting code isn't able to
4560 * serialize non-blocking commits happening on the real DP connector of an MST topology switching
4561 * into/away from MST mode - as the CRTC on the real DP connector and the CRTCs on the connector's
4562 * MST topology will never share the same &drm_encoder.
4563 *
4564 * This function takes care of this serialization issue, by checking a root MST connector's atomic
4565 * state to determine if it is about to have a modeset - and then pulling in the MST topology state
4566 * if so, along with adding any relevant CRTCs to &drm_dp_mst_topology_state.pending_crtc_mask.
4567 *
4568 * Drivers implementing MST must call this function from the
4569 * &drm_connector_helper_funcs.atomic_check hook of any physical DP &drm_connector capable of
4570 * driving MST sinks.
4571 *
4572 * Returns:
4573 * 0 on success, negative error code otherwise
4574 */
4575int drm_dp_mst_root_conn_atomic_check(struct drm_connector_state *new_conn_state,
4576				      struct drm_dp_mst_topology_mgr *mgr)
4577{
4578	struct drm_atomic_state *state = new_conn_state->state;
4579	struct drm_connector_state *old_conn_state =
4580		drm_atomic_get_old_connector_state(state, new_conn_state->connector);
4581	struct drm_crtc_state *crtc_state;
4582	struct drm_dp_mst_topology_state *mst_state = NULL;
4583
4584	if (new_conn_state->crtc) {
4585		crtc_state = drm_atomic_get_new_crtc_state(state, new_conn_state->crtc);
4586		if (crtc_state && drm_atomic_crtc_needs_modeset(crtc_state)) {
4587			mst_state = drm_atomic_get_mst_topology_state(state, mgr);
4588			if (IS_ERR(mst_state))
4589				return PTR_ERR(mst_state);
4590
4591			mst_state->pending_crtc_mask |= drm_crtc_mask(new_conn_state->crtc);
4592		}
4593	}
4594
4595	if (old_conn_state->crtc) {
4596		crtc_state = drm_atomic_get_new_crtc_state(state, old_conn_state->crtc);
4597		if (crtc_state && drm_atomic_crtc_needs_modeset(crtc_state)) {
4598			if (!mst_state) {
4599				mst_state = drm_atomic_get_mst_topology_state(state, mgr);
4600				if (IS_ERR(mst_state))
4601					return PTR_ERR(mst_state);
4602			}
4603
4604			mst_state->pending_crtc_mask |= drm_crtc_mask(old_conn_state->crtc);
4605		}
4606	}
4607
4608	return 0;
4609}
4610EXPORT_SYMBOL(drm_dp_mst_root_conn_atomic_check);
4611
4612/**
4613 * drm_dp_mst_update_slots() - updates the slot info depending on the DP ecoding format
4614 * @mst_state: mst_state to update
4615 * @link_encoding_cap: the ecoding format on the link
4616 */
4617void drm_dp_mst_update_slots(struct drm_dp_mst_topology_state *mst_state, uint8_t link_encoding_cap)
4618{
4619	if (link_encoding_cap == DP_CAP_ANSI_128B132B) {
4620		mst_state->total_avail_slots = 64;
4621		mst_state->start_slot = 0;
4622	} else {
4623		mst_state->total_avail_slots = 63;
4624		mst_state->start_slot = 1;
4625	}
4626
4627	DRM_DEBUG_KMS("%s encoding format on mst_state 0x%p\n",
4628		      (link_encoding_cap == DP_CAP_ANSI_128B132B) ? "128b/132b":"8b/10b",
4629		      mst_state);
4630}
4631EXPORT_SYMBOL(drm_dp_mst_update_slots);
4632
4633static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
4634				     int id, u8 start_slot, u8 num_slots)
4635{
4636	u8 payload_alloc[3], status;
4637	int ret;
4638	int retries = 0;
4639
4640	drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
4641			   DP_PAYLOAD_TABLE_UPDATED);
4642
4643	payload_alloc[0] = id;
4644	payload_alloc[1] = start_slot;
4645	payload_alloc[2] = num_slots;
4646
4647	ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
4648	if (ret != 3) {
4649		drm_dbg_kms(mgr->dev, "failed to write payload allocation %d\n", ret);
4650		goto fail;
4651	}
4652
4653retry:
4654	ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4655	if (ret < 0) {
4656		drm_dbg_kms(mgr->dev, "failed to read payload table status %d\n", ret);
4657		goto fail;
4658	}
4659
4660	if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
4661		retries++;
4662		if (retries < 20) {
4663			usleep_range(10000, 20000);
4664			goto retry;
4665		}
4666		drm_dbg_kms(mgr->dev, "status not set after read payload table status %d\n",
4667			    status);
4668		ret = -EINVAL;
4669		goto fail;
4670	}
4671	ret = 0;
4672fail:
4673	return ret;
4674}
4675
4676static int do_get_act_status(struct drm_dp_aux *aux)
4677{
4678	int ret;
4679	u8 status;
4680
4681	ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4682	if (ret < 0)
4683		return ret;
4684
4685	return status;
4686}
4687
4688/**
4689 * drm_dp_check_act_status() - Polls for ACT handled status.
4690 * @mgr: manager to use
4691 *
4692 * Tries waiting for the MST hub to finish updating it's payload table by
4693 * polling for the ACT handled bit for up to 3 seconds (yes-some hubs really
4694 * take that long).
4695 *
4696 * Returns:
4697 * 0 if the ACT was handled in time, negative error code on failure.
4698 */
4699int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
4700{
4701	/*
4702	 * There doesn't seem to be any recommended retry count or timeout in
4703	 * the MST specification. Since some hubs have been observed to take
4704	 * over 1 second to update their payload allocations under certain
4705	 * conditions, we use a rather large timeout value.
4706	 */
4707	const int timeout_ms = 3000;
4708	int ret, status;
4709
4710	ret = readx_poll_timeout(do_get_act_status, mgr->aux, status,
4711				 status & DP_PAYLOAD_ACT_HANDLED || status < 0,
4712				 200, timeout_ms * USEC_PER_MSEC);
4713	if (ret < 0 && status >= 0) {
4714		drm_err(mgr->dev, "Failed to get ACT after %dms, last status: %02x\n",
4715			timeout_ms, status);
4716		return -EINVAL;
4717	} else if (status < 0) {
4718		/*
4719		 * Failure here isn't unexpected - the hub may have
4720		 * just been unplugged
4721		 */
4722		drm_dbg_kms(mgr->dev, "Failed to read payload table status: %d\n", status);
4723		return status;
4724	}
4725
4726	return 0;
4727}
4728EXPORT_SYMBOL(drm_dp_check_act_status);
4729
4730/**
4731 * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
4732 * @clock: dot clock
4733 * @bpp: bpp as .4 binary fixed point
4734 *
4735 * This uses the formula in the spec to calculate the PBN value for a mode.
4736 */
4737int drm_dp_calc_pbn_mode(int clock, int bpp)
4738{
4739	/*
4740	 * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on
4741	 * common multiplier to render an integer PBN for all link rate/lane
4742	 * counts combinations
4743	 * calculate
4744	 * peak_kbps = clock * bpp / 16
4745	 * peak_kbps *= SSC overhead / 1000000
4746	 * peak_kbps /= 8    convert to Kbytes
4747	 * peak_kBps *= (64/54) / 1000    convert to PBN
4748	 */
4749	/*
4750	 * TODO: Use the actual link and mode parameters to calculate
4751	 * the overhead. For now it's assumed that these are
4752	 * 4 link lanes, 4096 hactive pixels, which don't add any
4753	 * significant data padding overhead and that there is no DSC
4754	 * or FEC overhead.
4755	 */
4756	int overhead = drm_dp_bw_overhead(4, 4096, 0, bpp,
4757					  DRM_DP_BW_OVERHEAD_MST |
4758					  DRM_DP_BW_OVERHEAD_SSC_REF_CLK);
4759
4760	return DIV64_U64_ROUND_UP(mul_u32_u32(clock * bpp, 64 * overhead >> 4),
4761				  1000000ULL * 8 * 54 * 1000);
4762}
4763EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
4764
4765/* we want to kick the TX after we've ack the up/down IRQs. */
4766static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
4767{
4768	queue_work(system_long_wq, &mgr->tx_work);
4769}
4770
4771/*
4772 * Helper function for parsing DP device types into convenient strings
4773 * for use with dp_mst_topology
4774 */
4775static const char *pdt_to_string(u8 pdt)
4776{
4777	switch (pdt) {
4778	case DP_PEER_DEVICE_NONE:
4779		return "NONE";
4780	case DP_PEER_DEVICE_SOURCE_OR_SST:
4781		return "SOURCE OR SST";
4782	case DP_PEER_DEVICE_MST_BRANCHING:
4783		return "MST BRANCHING";
4784	case DP_PEER_DEVICE_SST_SINK:
4785		return "SST SINK";
4786	case DP_PEER_DEVICE_DP_LEGACY_CONV:
4787		return "DP LEGACY CONV";
4788	default:
4789		return "ERR";
4790	}
4791}
4792
4793static void drm_dp_mst_dump_mstb(struct seq_file *m,
4794				 struct drm_dp_mst_branch *mstb)
4795{
4796	struct drm_dp_mst_port *port;
4797	int tabs = mstb->lct;
4798	char prefix[10];
4799	int i;
4800
4801	for (i = 0; i < tabs; i++)
4802		prefix[i] = '\t';
4803	prefix[i] = '\0';
4804
4805	seq_printf(m, "%smstb - [%p]: num_ports: %d\n", prefix, mstb, mstb->num_ports);
4806	list_for_each_entry(port, &mstb->ports, next) {
4807		seq_printf(m, "%sport %d - [%p] (%s - %s): ddps: %d, ldps: %d, sdp: %d/%d, fec: %s, conn: %p\n",
4808			   prefix,
4809			   port->port_num,
4810			   port,
4811			   port->input ? "input" : "output",
4812			   pdt_to_string(port->pdt),
4813			   port->ddps,
4814			   port->ldps,
4815			   port->num_sdp_streams,
4816			   port->num_sdp_stream_sinks,
4817			   port->fec_capable ? "true" : "false",
4818			   port->connector);
4819		if (port->mstb)
4820			drm_dp_mst_dump_mstb(m, port->mstb);
4821	}
4822}
4823
4824#define DP_PAYLOAD_TABLE_SIZE		64
4825
4826static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
4827				  char *buf)
4828{
4829	int i;
4830
4831	for (i = 0; i < DP_PAYLOAD_TABLE_SIZE; i += 16) {
4832		if (drm_dp_dpcd_read(mgr->aux,
4833				     DP_PAYLOAD_TABLE_UPDATE_STATUS + i,
4834				     &buf[i], 16) != 16)
4835			return false;
4836	}
4837	return true;
4838}
4839
4840static void fetch_monitor_name(struct drm_dp_mst_topology_mgr *mgr,
4841			       struct drm_dp_mst_port *port, char *name,
4842			       int namelen)
4843{
4844	struct edid *mst_edid;
4845
4846	mst_edid = drm_dp_mst_get_edid(port->connector, mgr, port);
4847	drm_edid_get_monitor_name(mst_edid, name, namelen);
4848	kfree(mst_edid);
4849}
4850
4851/**
4852 * drm_dp_mst_dump_topology(): dump topology to seq file.
4853 * @m: seq_file to dump output to
4854 * @mgr: manager to dump current topology for.
4855 *
4856 * helper to dump MST topology to a seq file for debugfs.
4857 */
4858void drm_dp_mst_dump_topology(struct seq_file *m,
4859			      struct drm_dp_mst_topology_mgr *mgr)
4860{
4861	struct drm_dp_mst_topology_state *state;
4862	struct drm_dp_mst_atomic_payload *payload;
4863	int i, ret;
4864
4865	static const char *const status[] = {
4866		"None",
4867		"Local",
4868		"DFP",
4869		"Remote",
4870	};
4871
4872	mutex_lock(&mgr->lock);
4873	if (mgr->mst_primary)
4874		drm_dp_mst_dump_mstb(m, mgr->mst_primary);
4875
4876	/* dump VCPIs */
4877	mutex_unlock(&mgr->lock);
4878
4879	ret = drm_modeset_lock_single_interruptible(&mgr->base.lock);
4880	if (ret < 0)
4881		return;
4882
4883	state = to_drm_dp_mst_topology_state(mgr->base.state);
4884	seq_printf(m, "\n*** Atomic state info ***\n");
4885	seq_printf(m, "payload_mask: %x, max_payloads: %d, start_slot: %u, pbn_div: %d\n",
4886		   state->payload_mask, mgr->max_payloads, state->start_slot,
4887		   dfixed_trunc(state->pbn_div));
4888
4889	seq_printf(m, "\n| idx | port | vcpi | slots | pbn | dsc | status |     sink name     |\n");
4890	for (i = 0; i < mgr->max_payloads; i++) {
4891		list_for_each_entry(payload, &state->payloads, next) {
4892			char name[14];
4893
4894			if (payload->vcpi != i || payload->delete)
4895				continue;
4896
4897			fetch_monitor_name(mgr, payload->port, name, sizeof(name));
4898			seq_printf(m, " %5d %6d %6d %02d - %02d %5d %5s %8s %19s\n",
4899				   i,
4900				   payload->port->port_num,
4901				   payload->vcpi,
4902				   payload->vc_start_slot,
4903				   payload->vc_start_slot + payload->time_slots - 1,
4904				   payload->pbn,
4905				   payload->dsc_enabled ? "Y" : "N",
4906				   status[payload->payload_allocation_status],
4907				   (*name != 0) ? name : "Unknown");
4908		}
4909	}
4910
4911	seq_printf(m, "\n*** DPCD Info ***\n");
4912	mutex_lock(&mgr->lock);
4913	if (mgr->mst_primary) {
4914		u8 buf[DP_PAYLOAD_TABLE_SIZE];
4915		int ret;
4916
4917		if (drm_dp_read_dpcd_caps(mgr->aux, buf) < 0) {
4918			seq_printf(m, "dpcd read failed\n");
4919			goto out;
4920		}
4921		seq_printf(m, "dpcd: %*ph\n", DP_RECEIVER_CAP_SIZE, buf);
4922
4923		ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
4924		if (ret != 2) {
4925			seq_printf(m, "faux/mst read failed\n");
4926			goto out;
4927		}
4928		seq_printf(m, "faux/mst: %*ph\n", 2, buf);
4929
4930		ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
4931		if (ret != 1) {
4932			seq_printf(m, "mst ctrl read failed\n");
4933			goto out;
4934		}
4935		seq_printf(m, "mst ctrl: %*ph\n", 1, buf);
4936
4937		/* dump the standard OUI branch header */
4938		ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
4939		if (ret != DP_BRANCH_OUI_HEADER_SIZE) {
4940			seq_printf(m, "branch oui read failed\n");
4941			goto out;
4942		}
4943		seq_printf(m, "branch oui: %*phN devid: ", 3, buf);
4944
4945		for (i = 0x3; i < 0x8 && buf[i]; i++)
4946			seq_printf(m, "%c", buf[i]);
4947		seq_printf(m, " revision: hw: %x.%x sw: %x.%x\n",
4948			   buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]);
4949		if (dump_dp_payload_table(mgr, buf))
4950			seq_printf(m, "payload table: %*ph\n", DP_PAYLOAD_TABLE_SIZE, buf);
4951	}
4952
4953out:
4954	mutex_unlock(&mgr->lock);
4955	drm_modeset_unlock(&mgr->base.lock);
4956}
4957EXPORT_SYMBOL(drm_dp_mst_dump_topology);
4958
4959static void drm_dp_tx_work(struct work_struct *work)
4960{
4961	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
4962
4963	mutex_lock(&mgr->qlock);
4964	if (!list_empty(&mgr->tx_msg_downq))
4965		process_single_down_tx_qlock(mgr);
4966	mutex_unlock(&mgr->qlock);
4967}
4968
4969static inline void
4970drm_dp_delayed_destroy_port(struct drm_dp_mst_port *port)
4971{
4972	drm_dp_port_set_pdt(port, DP_PEER_DEVICE_NONE, port->mcs);
4973
4974	if (port->connector) {
4975		drm_connector_unregister(port->connector);
4976		drm_connector_put(port->connector);
4977	}
4978
4979	drm_dp_mst_put_port_malloc(port);
4980}
4981
4982static inline void
4983drm_dp_delayed_destroy_mstb(struct drm_dp_mst_branch *mstb)
4984{
4985	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
4986	struct drm_dp_mst_port *port, *port_tmp;
4987	struct drm_dp_sideband_msg_tx *txmsg, *txmsg_tmp;
4988	bool wake_tx = false;
4989
4990	mutex_lock(&mgr->lock);
4991	list_for_each_entry_safe(port, port_tmp, &mstb->ports, next) {
4992		list_del(&port->next);
4993		drm_dp_mst_topology_put_port(port);
4994	}
4995	mutex_unlock(&mgr->lock);
4996
4997	/* drop any tx slot msg */
4998	mutex_lock(&mstb->mgr->qlock);
4999	list_for_each_entry_safe(txmsg, txmsg_tmp, &mgr->tx_msg_downq, next) {
5000		if (txmsg->dst != mstb)
5001			continue;
5002
5003		txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
5004		list_del(&txmsg->next);
5005		wake_tx = true;
5006	}
5007	mutex_unlock(&mstb->mgr->qlock);
5008
5009	if (wake_tx)
5010		wake_up_all(&mstb->mgr->tx_waitq);
5011
5012	drm_dp_mst_put_mstb_malloc(mstb);
5013}
5014
5015static void drm_dp_delayed_destroy_work(struct work_struct *work)
5016{
5017	struct drm_dp_mst_topology_mgr *mgr =
5018		container_of(work, struct drm_dp_mst_topology_mgr,
5019			     delayed_destroy_work);
5020	bool send_hotplug = false, go_again;
5021
5022	/*
5023	 * Not a regular list traverse as we have to drop the destroy
5024	 * connector lock before destroying the mstb/port, to avoid AB->BA
5025	 * ordering between this lock and the config mutex.
5026	 */
5027	do {
5028		go_again = false;
5029
5030		for (;;) {
5031			struct drm_dp_mst_branch *mstb;
5032
5033			mutex_lock(&mgr->delayed_destroy_lock);
5034			mstb = list_first_entry_or_null(&mgr->destroy_branch_device_list,
5035							struct drm_dp_mst_branch,
5036							destroy_next);
5037			if (mstb)
5038				list_del(&mstb->destroy_next);
5039			mutex_unlock(&mgr->delayed_destroy_lock);
5040
5041			if (!mstb)
5042				break;
5043
5044			drm_dp_delayed_destroy_mstb(mstb);
5045			go_again = true;
5046		}
5047
5048		for (;;) {
5049			struct drm_dp_mst_port *port;
5050
5051			mutex_lock(&mgr->delayed_destroy_lock);
5052			port = list_first_entry_or_null(&mgr->destroy_port_list,
5053							struct drm_dp_mst_port,
5054							next);
5055			if (port)
5056				list_del(&port->next);
5057			mutex_unlock(&mgr->delayed_destroy_lock);
5058
5059			if (!port)
5060				break;
5061
5062			drm_dp_delayed_destroy_port(port);
5063			send_hotplug = true;
5064			go_again = true;
5065		}
5066	} while (go_again);
5067
5068	if (send_hotplug)
5069		drm_kms_helper_hotplug_event(mgr->dev);
5070}
5071
5072static struct drm_private_state *
5073drm_dp_mst_duplicate_state(struct drm_private_obj *obj)
5074{
5075	struct drm_dp_mst_topology_state *state, *old_state =
5076		to_dp_mst_topology_state(obj->state);
5077	struct drm_dp_mst_atomic_payload *pos, *payload;
5078
5079	state = kmemdup(old_state, sizeof(*state), GFP_KERNEL);
5080	if (!state)
5081		return NULL;
5082
5083	__drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
5084
5085	INIT_LIST_HEAD(&state->payloads);
5086	state->commit_deps = NULL;
5087	state->num_commit_deps = 0;
5088	state->pending_crtc_mask = 0;
5089
5090	list_for_each_entry(pos, &old_state->payloads, next) {
5091		/* Prune leftover freed timeslot allocations */
5092		if (pos->delete)
5093			continue;
5094
5095		payload = kmemdup(pos, sizeof(*payload), GFP_KERNEL);
5096		if (!payload)
5097			goto fail;
5098
5099		drm_dp_mst_get_port_malloc(payload->port);
5100		list_add(&payload->next, &state->payloads);
5101	}
5102
5103	return &state->base;
5104
5105fail:
5106	list_for_each_entry_safe(pos, payload, &state->payloads, next) {
5107		drm_dp_mst_put_port_malloc(pos->port);
5108		kfree(pos);
5109	}
5110	kfree(state);
5111
5112	return NULL;
5113}
5114
5115static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
5116				     struct drm_private_state *state)
5117{
5118	struct drm_dp_mst_topology_state *mst_state =
5119		to_dp_mst_topology_state(state);
5120	struct drm_dp_mst_atomic_payload *pos, *tmp;
5121	int i;
5122
5123	list_for_each_entry_safe(pos, tmp, &mst_state->payloads, next) {
5124		/* We only keep references to ports with active payloads */
5125		if (!pos->delete)
5126			drm_dp_mst_put_port_malloc(pos->port);
5127		kfree(pos);
5128	}
5129
5130	for (i = 0; i < mst_state->num_commit_deps; i++)
5131		drm_crtc_commit_put(mst_state->commit_deps[i]);
5132
5133	kfree(mst_state->commit_deps);
5134	kfree(mst_state);
5135}
5136
5137static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
5138						 struct drm_dp_mst_branch *branch)
5139{
5140	while (port->parent) {
5141		if (port->parent == branch)
5142			return true;
5143
5144		if (port->parent->port_parent)
5145			port = port->parent->port_parent;
5146		else
5147			break;
5148	}
5149	return false;
5150}
5151
5152static bool
5153drm_dp_mst_port_downstream_of_parent_locked(struct drm_dp_mst_topology_mgr *mgr,
5154					    struct drm_dp_mst_port *port,
5155					    struct drm_dp_mst_port *parent)
5156{
5157	if (!mgr->mst_primary)
5158		return false;
5159
5160	port = drm_dp_mst_topology_get_port_validated_locked(mgr->mst_primary,
5161							     port);
5162	if (!port)
5163		return false;
5164
5165	if (!parent)
5166		return true;
5167
5168	parent = drm_dp_mst_topology_get_port_validated_locked(mgr->mst_primary,
5169							       parent);
5170	if (!parent)
5171		return false;
5172
5173	if (!parent->mstb)
5174		return false;
5175
5176	return drm_dp_mst_port_downstream_of_branch(port, parent->mstb);
5177}
5178
5179/**
5180 * drm_dp_mst_port_downstream_of_parent - check if a port is downstream of a parent port
5181 * @mgr: MST topology manager
5182 * @port: the port being looked up
5183 * @parent: the parent port
5184 *
5185 * The function returns %true if @port is downstream of @parent. If @parent is
5186 * %NULL - denoting the root port - the function returns %true if @port is in
5187 * @mgr's topology.
5188 */
5189bool
5190drm_dp_mst_port_downstream_of_parent(struct drm_dp_mst_topology_mgr *mgr,
5191				     struct drm_dp_mst_port *port,
5192				     struct drm_dp_mst_port *parent)
5193{
5194	bool ret;
5195
5196	mutex_lock(&mgr->lock);
5197	ret = drm_dp_mst_port_downstream_of_parent_locked(mgr, port, parent);
5198	mutex_unlock(&mgr->lock);
5199
5200	return ret;
5201}
5202EXPORT_SYMBOL(drm_dp_mst_port_downstream_of_parent);
5203
5204static int
5205drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5206				      struct drm_dp_mst_topology_state *state,
5207				      struct drm_dp_mst_port **failing_port);
5208
5209static int
5210drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb,
5211				      struct drm_dp_mst_topology_state *state,
5212				      struct drm_dp_mst_port **failing_port)
5213{
5214	struct drm_dp_mst_atomic_payload *payload;
5215	struct drm_dp_mst_port *port;
5216	int pbn_used = 0, ret;
5217	bool found = false;
5218
5219	/* Check that we have at least one port in our state that's downstream
5220	 * of this branch, otherwise we can skip this branch
5221	 */
5222	list_for_each_entry(payload, &state->payloads, next) {
5223		if (!payload->pbn ||
5224		    !drm_dp_mst_port_downstream_of_branch(payload->port, mstb))
5225			continue;
5226
5227		found = true;
5228		break;
5229	}
5230	if (!found)
5231		return 0;
5232
5233	if (mstb->port_parent)
5234		drm_dbg_atomic(mstb->mgr->dev,
5235			       "[MSTB:%p] [MST PORT:%p] Checking bandwidth limits on [MSTB:%p]\n",
5236			       mstb->port_parent->parent, mstb->port_parent, mstb);
5237	else
5238		drm_dbg_atomic(mstb->mgr->dev, "[MSTB:%p] Checking bandwidth limits\n", mstb);
5239
5240	list_for_each_entry(port, &mstb->ports, next) {
5241		ret = drm_dp_mst_atomic_check_port_bw_limit(port, state, failing_port);
5242		if (ret < 0)
5243			return ret;
5244
5245		pbn_used += ret;
5246	}
5247
5248	return pbn_used;
5249}
5250
5251static int
5252drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5253				      struct drm_dp_mst_topology_state *state,
5254				      struct drm_dp_mst_port **failing_port)
5255{
5256	struct drm_dp_mst_atomic_payload *payload;
5257	int pbn_used = 0;
5258
5259	if (port->pdt == DP_PEER_DEVICE_NONE)
5260		return 0;
5261
5262	if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
5263		payload = drm_atomic_get_mst_payload_state(state, port);
5264		if (!payload)
5265			return 0;
5266
5267		/*
5268		 * This could happen if the sink deasserted its HPD line, but
5269		 * the branch device still reports it as attached (PDT != NONE).
5270		 */
5271		if (!port->full_pbn) {
5272			drm_dbg_atomic(port->mgr->dev,
5273				       "[MSTB:%p] [MST PORT:%p] no BW available for the port\n",
5274				       port->parent, port);
5275			*failing_port = port;
5276			return -EINVAL;
5277		}
5278
5279		pbn_used = payload->pbn;
5280	} else {
5281		pbn_used = drm_dp_mst_atomic_check_mstb_bw_limit(port->mstb,
5282								 state,
5283								 failing_port);
5284		if (pbn_used <= 0)
5285			return pbn_used;
5286	}
5287
5288	if (pbn_used > port->full_pbn) {
5289		drm_dbg_atomic(port->mgr->dev,
5290			       "[MSTB:%p] [MST PORT:%p] required PBN of %d exceeds port limit of %d\n",
5291			       port->parent, port, pbn_used, port->full_pbn);
5292		*failing_port = port;
5293		return -ENOSPC;
5294	}
5295
5296	drm_dbg_atomic(port->mgr->dev, "[MSTB:%p] [MST PORT:%p] uses %d out of %d PBN\n",
5297		       port->parent, port, pbn_used, port->full_pbn);
5298
5299	return pbn_used;
5300}
5301
5302static inline int
5303drm_dp_mst_atomic_check_payload_alloc_limits(struct drm_dp_mst_topology_mgr *mgr,
5304					     struct drm_dp_mst_topology_state *mst_state)
5305{
5306	struct drm_dp_mst_atomic_payload *payload;
5307	int avail_slots = mst_state->total_avail_slots, payload_count = 0;
5308
5309	list_for_each_entry(payload, &mst_state->payloads, next) {
5310		/* Releasing payloads is always OK-even if the port is gone */
5311		if (payload->delete) {
5312			drm_dbg_atomic(mgr->dev, "[MST PORT:%p] releases all time slots\n",
5313				       payload->port);
5314			continue;
5315		}
5316
5317		drm_dbg_atomic(mgr->dev, "[MST PORT:%p] requires %d time slots\n",
5318			       payload->port, payload->time_slots);
5319
5320		avail_slots -= payload->time_slots;
5321		if (avail_slots < 0) {
5322			drm_dbg_atomic(mgr->dev,
5323				       "[MST PORT:%p] not enough time slots in mst state %p (avail=%d)\n",
5324				       payload->port, mst_state, avail_slots + payload->time_slots);
5325			return -ENOSPC;
5326		}
5327
5328		if (++payload_count > mgr->max_payloads) {
5329			drm_dbg_atomic(mgr->dev,
5330				       "[MST MGR:%p] state %p has too many payloads (max=%d)\n",
5331				       mgr, mst_state, mgr->max_payloads);
5332			return -EINVAL;
5333		}
5334
5335		/* Assign a VCPI */
5336		if (!payload->vcpi) {
5337			payload->vcpi = ffz(mst_state->payload_mask) + 1;
5338			drm_dbg_atomic(mgr->dev, "[MST PORT:%p] assigned VCPI #%d\n",
5339				       payload->port, payload->vcpi);
5340			mst_state->payload_mask |= BIT(payload->vcpi - 1);
5341		}
5342	}
5343
5344	if (!payload_count)
5345		mst_state->pbn_div.full = dfixed_const(0);
5346
5347	drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p TU pbn_div=%d avail=%d used=%d\n",
5348		       mgr, mst_state, dfixed_trunc(mst_state->pbn_div), avail_slots,
5349		       mst_state->total_avail_slots - avail_slots);
5350
5351	return 0;
5352}
5353
5354/**
5355 * drm_dp_mst_add_affected_dsc_crtcs
5356 * @state: Pointer to the new struct drm_dp_mst_topology_state
5357 * @mgr: MST topology manager
5358 *
5359 * Whenever there is a change in mst topology
5360 * DSC configuration would have to be recalculated
5361 * therefore we need to trigger modeset on all affected
5362 * CRTCs in that topology
5363 *
5364 * See also:
5365 * drm_dp_mst_atomic_enable_dsc()
5366 */
5367int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state, struct drm_dp_mst_topology_mgr *mgr)
5368{
5369	struct drm_dp_mst_topology_state *mst_state;
5370	struct drm_dp_mst_atomic_payload *pos;
5371	struct drm_connector *connector;
5372	struct drm_connector_state *conn_state;
5373	struct drm_crtc *crtc;
5374	struct drm_crtc_state *crtc_state;
5375
5376	mst_state = drm_atomic_get_mst_topology_state(state, mgr);
5377
5378	if (IS_ERR(mst_state))
5379		return PTR_ERR(mst_state);
5380
5381	list_for_each_entry(pos, &mst_state->payloads, next) {
5382
5383		connector = pos->port->connector;
5384
5385		if (!connector)
5386			return -EINVAL;
5387
5388		conn_state = drm_atomic_get_connector_state(state, connector);
5389
5390		if (IS_ERR(conn_state))
5391			return PTR_ERR(conn_state);
5392
5393		crtc = conn_state->crtc;
5394
5395		if (!crtc)
5396			continue;
5397
5398		if (!drm_dp_mst_dsc_aux_for_port(pos->port))
5399			continue;
5400
5401		crtc_state = drm_atomic_get_crtc_state(mst_state->base.state, crtc);
5402
5403		if (IS_ERR(crtc_state))
5404			return PTR_ERR(crtc_state);
5405
5406		drm_dbg_atomic(mgr->dev, "[MST MGR:%p] Setting mode_changed flag on CRTC %p\n",
5407			       mgr, crtc);
5408
5409		crtc_state->mode_changed = true;
5410	}
5411	return 0;
5412}
5413EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
5414
5415/**
5416 * drm_dp_mst_atomic_enable_dsc - Set DSC Enable Flag to On/Off
5417 * @state: Pointer to the new drm_atomic_state
5418 * @port: Pointer to the affected MST Port
5419 * @pbn: Newly recalculated bw required for link with DSC enabled
5420 * @enable: Boolean flag to enable or disable DSC on the port
5421 *
5422 * This function enables DSC on the given Port
5423 * by recalculating its vcpi from pbn provided
5424 * and sets dsc_enable flag to keep track of which
5425 * ports have DSC enabled
5426 *
5427 */
5428int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
5429				 struct drm_dp_mst_port *port,
5430				 int pbn, bool enable)
5431{
5432	struct drm_dp_mst_topology_state *mst_state;
5433	struct drm_dp_mst_atomic_payload *payload;
5434	int time_slots = 0;
5435
5436	mst_state = drm_atomic_get_mst_topology_state(state, port->mgr);
5437	if (IS_ERR(mst_state))
5438		return PTR_ERR(mst_state);
5439
5440	payload = drm_atomic_get_mst_payload_state(mst_state, port);
5441	if (!payload) {
5442		drm_dbg_atomic(state->dev,
5443			       "[MST PORT:%p] Couldn't find payload in mst state %p\n",
5444			       port, mst_state);
5445		return -EINVAL;
5446	}
5447
5448	if (payload->dsc_enabled == enable) {
5449		drm_dbg_atomic(state->dev,
5450			       "[MST PORT:%p] DSC flag is already set to %d, returning %d time slots\n",
5451			       port, enable, payload->time_slots);
5452		time_slots = payload->time_slots;
5453	}
5454
5455	if (enable) {
5456		time_slots = drm_dp_atomic_find_time_slots(state, port->mgr, port, pbn);
5457		drm_dbg_atomic(state->dev,
5458			       "[MST PORT:%p] Enabling DSC flag, reallocating %d time slots on the port\n",
5459			       port, time_slots);
5460		if (time_slots < 0)
5461			return -EINVAL;
5462	}
5463
5464	payload->dsc_enabled = enable;
5465
5466	return time_slots;
5467}
5468EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
5469
5470/**
5471 * drm_dp_mst_atomic_check_mgr - Check the atomic state of an MST topology manager
5472 * @state: The global atomic state
5473 * @mgr: Manager to check
5474 * @mst_state: The MST atomic state for @mgr
5475 * @failing_port: Returns the port with a BW limitation
5476 *
5477 * Checks the given MST manager's topology state for an atomic update to ensure
5478 * that it's valid. This includes checking whether there's enough bandwidth to
5479 * support the new timeslot allocations in the atomic update.
5480 *
5481 * Any atomic drivers supporting DP MST must make sure to call this or
5482 * the drm_dp_mst_atomic_check() function after checking the rest of their state
5483 * in their &drm_mode_config_funcs.atomic_check() callback.
5484 *
5485 * See also:
5486 * drm_dp_mst_atomic_check()
5487 * drm_dp_atomic_find_time_slots()
5488 * drm_dp_atomic_release_time_slots()
5489 *
5490 * Returns:
5491 *   - 0 if the new state is valid
5492 *   - %-ENOSPC, if the new state is invalid, because of BW limitation
5493 *         @failing_port is set to:
5494 *
5495 *         - The non-root port where a BW limit check failed
5496 *           with all the ports downstream of @failing_port passing
5497 *           the BW limit check.
5498 *           The returned port pointer is valid until at least
5499 *           one payload downstream of it exists.
5500 *         - %NULL if the BW limit check failed at the root port
5501 *           with all the ports downstream of the root port passing
5502 *           the BW limit check.
5503 *
5504 *   - %-EINVAL, if the new state is invalid, because the root port has
5505 *     too many payloads.
5506 */
5507int drm_dp_mst_atomic_check_mgr(struct drm_atomic_state *state,
5508				struct drm_dp_mst_topology_mgr *mgr,
5509				struct drm_dp_mst_topology_state *mst_state,
5510				struct drm_dp_mst_port **failing_port)
5511{
5512	int ret;
5513
5514	*failing_port = NULL;
5515
5516	if (!mgr->mst_state)
5517		return 0;
5518
5519	mutex_lock(&mgr->lock);
5520	ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary,
5521						    mst_state,
5522						    failing_port);
5523	mutex_unlock(&mgr->lock);
5524
5525	if (ret < 0)
5526		return ret;
5527
5528	return drm_dp_mst_atomic_check_payload_alloc_limits(mgr, mst_state);
5529}
5530EXPORT_SYMBOL(drm_dp_mst_atomic_check_mgr);
5531
5532/**
5533 * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
5534 * atomic update is valid
5535 * @state: Pointer to the new &struct drm_dp_mst_topology_state
5536 *
5537 * Checks the given topology state for an atomic update to ensure that it's
5538 * valid, calling drm_dp_mst_atomic_check_mgr() for all MST manager in the
5539 * atomic state. This includes checking whether there's enough bandwidth to
5540 * support the new timeslot allocations in the atomic update.
5541 *
5542 * Any atomic drivers supporting DP MST must make sure to call this after
5543 * checking the rest of their state in their
5544 * &drm_mode_config_funcs.atomic_check() callback.
5545 *
5546 * See also:
5547 * drm_dp_mst_atomic_check_mgr()
5548 * drm_dp_atomic_find_time_slots()
5549 * drm_dp_atomic_release_time_slots()
5550 *
5551 * Returns:
5552 *
5553 * 0 if the new state is valid, negative error code otherwise.
5554 */
5555int drm_dp_mst_atomic_check(struct drm_atomic_state *state)
5556{
5557	struct drm_dp_mst_topology_mgr *mgr;
5558	struct drm_dp_mst_topology_state *mst_state;
5559	int i, ret = 0;
5560
5561	for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
5562		struct drm_dp_mst_port *tmp_port;
5563
5564		ret = drm_dp_mst_atomic_check_mgr(state, mgr, mst_state, &tmp_port);
5565		if (ret)
5566			break;
5567	}
5568
5569	return ret;
5570}
5571EXPORT_SYMBOL(drm_dp_mst_atomic_check);
5572
5573const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs = {
5574	.atomic_duplicate_state = drm_dp_mst_duplicate_state,
5575	.atomic_destroy_state = drm_dp_mst_destroy_state,
5576};
5577EXPORT_SYMBOL(drm_dp_mst_topology_state_funcs);
5578
5579/**
5580 * drm_atomic_get_mst_topology_state: get MST topology state
5581 * @state: global atomic state
5582 * @mgr: MST topology manager, also the private object in this case
5583 *
5584 * This function wraps drm_atomic_get_priv_obj_state() passing in the MST atomic
5585 * state vtable so that the private object state returned is that of a MST
5586 * topology object.
5587 *
5588 * RETURNS:
5589 *
5590 * The MST topology state or error pointer.
5591 */
5592struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
5593								    struct drm_dp_mst_topology_mgr *mgr)
5594{
5595	return to_dp_mst_topology_state(drm_atomic_get_private_obj_state(state, &mgr->base));
5596}
5597EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
5598
5599/**
5600 * drm_atomic_get_old_mst_topology_state: get old MST topology state in atomic state, if any
5601 * @state: global atomic state
5602 * @mgr: MST topology manager, also the private object in this case
5603 *
5604 * This function wraps drm_atomic_get_old_private_obj_state() passing in the MST atomic
5605 * state vtable so that the private object state returned is that of a MST
5606 * topology object.
5607 *
5608 * Returns:
5609 *
5610 * The old MST topology state, or NULL if there's no topology state for this MST mgr
5611 * in the global atomic state
5612 */
5613struct drm_dp_mst_topology_state *
5614drm_atomic_get_old_mst_topology_state(struct drm_atomic_state *state,
5615				      struct drm_dp_mst_topology_mgr *mgr)
5616{
5617	struct drm_private_state *old_priv_state =
5618		drm_atomic_get_old_private_obj_state(state, &mgr->base);
5619
5620	return old_priv_state ? to_dp_mst_topology_state(old_priv_state) : NULL;
5621}
5622EXPORT_SYMBOL(drm_atomic_get_old_mst_topology_state);
5623
5624/**
5625 * drm_atomic_get_new_mst_topology_state: get new MST topology state in atomic state, if any
5626 * @state: global atomic state
5627 * @mgr: MST topology manager, also the private object in this case
5628 *
5629 * This function wraps drm_atomic_get_new_private_obj_state() passing in the MST atomic
5630 * state vtable so that the private object state returned is that of a MST
5631 * topology object.
5632 *
5633 * Returns:
5634 *
5635 * The new MST topology state, or NULL if there's no topology state for this MST mgr
5636 * in the global atomic state
5637 */
5638struct drm_dp_mst_topology_state *
5639drm_atomic_get_new_mst_topology_state(struct drm_atomic_state *state,
5640				      struct drm_dp_mst_topology_mgr *mgr)
5641{
5642	struct drm_private_state *new_priv_state =
5643		drm_atomic_get_new_private_obj_state(state, &mgr->base);
5644
5645	return new_priv_state ? to_dp_mst_topology_state(new_priv_state) : NULL;
5646}
5647EXPORT_SYMBOL(drm_atomic_get_new_mst_topology_state);
5648
5649/**
5650 * drm_dp_mst_topology_mgr_init - initialise a topology manager
5651 * @mgr: manager struct to initialise
5652 * @dev: device providing this structure - for i2c addition.
5653 * @aux: DP helper aux channel to talk to this device
5654 * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
5655 * @max_payloads: maximum number of payloads this GPU can source
5656 * @conn_base_id: the connector object ID the MST device is connected to.
5657 *
5658 * Return 0 for success, or negative error code on failure
5659 */
5660int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
5661				 struct drm_device *dev, struct drm_dp_aux *aux,
5662				 int max_dpcd_transaction_bytes, int max_payloads,
5663				 int conn_base_id)
5664{
5665	struct drm_dp_mst_topology_state *mst_state;
5666
5667	mutex_init(&mgr->lock);
5668	mutex_init(&mgr->qlock);
5669	mutex_init(&mgr->delayed_destroy_lock);
5670	mutex_init(&mgr->up_req_lock);
5671	mutex_init(&mgr->probe_lock);
5672#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5673	mutex_init(&mgr->topology_ref_history_lock);
5674	stack_depot_init();
5675#endif
5676	INIT_LIST_HEAD(&mgr->tx_msg_downq);
5677	INIT_LIST_HEAD(&mgr->destroy_port_list);
5678	INIT_LIST_HEAD(&mgr->destroy_branch_device_list);
5679	INIT_LIST_HEAD(&mgr->up_req_list);
5680
5681	/*
5682	 * delayed_destroy_work will be queued on a dedicated WQ, so that any
5683	 * requeuing will be also flushed when deiniting the topology manager.
5684	 */
5685	mgr->delayed_destroy_wq = alloc_ordered_workqueue("drm_dp_mst_wq", 0);
5686	if (mgr->delayed_destroy_wq == NULL)
5687		return -ENOMEM;
5688
5689	INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
5690	INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
5691	INIT_WORK(&mgr->delayed_destroy_work, drm_dp_delayed_destroy_work);
5692	INIT_WORK(&mgr->up_req_work, drm_dp_mst_up_req_work);
5693	init_waitqueue_head(&mgr->tx_waitq);
5694	mgr->dev = dev;
5695	mgr->aux = aux;
5696	mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
5697	mgr->max_payloads = max_payloads;
5698	mgr->conn_base_id = conn_base_id;
5699
5700	mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);
5701	if (mst_state == NULL)
5702		return -ENOMEM;
5703
5704	mst_state->total_avail_slots = 63;
5705	mst_state->start_slot = 1;
5706
5707	mst_state->mgr = mgr;
5708	INIT_LIST_HEAD(&mst_state->payloads);
5709
5710	drm_atomic_private_obj_init(dev, &mgr->base,
5711				    &mst_state->base,
5712				    &drm_dp_mst_topology_state_funcs);
5713
5714	return 0;
5715}
5716EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
5717
5718/**
5719 * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
5720 * @mgr: manager to destroy
5721 */
5722void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
5723{
5724	drm_dp_mst_topology_mgr_set_mst(mgr, false);
5725	flush_work(&mgr->work);
5726	/* The following will also drain any requeued work on the WQ. */
5727	if (mgr->delayed_destroy_wq) {
5728		destroy_workqueue(mgr->delayed_destroy_wq);
5729		mgr->delayed_destroy_wq = NULL;
5730	}
5731	mgr->dev = NULL;
5732	mgr->aux = NULL;
5733	drm_atomic_private_obj_fini(&mgr->base);
5734	mgr->funcs = NULL;
5735
5736	mutex_destroy(&mgr->delayed_destroy_lock);
5737	mutex_destroy(&mgr->qlock);
5738	mutex_destroy(&mgr->lock);
5739	mutex_destroy(&mgr->up_req_lock);
5740	mutex_destroy(&mgr->probe_lock);
5741#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5742	mutex_destroy(&mgr->topology_ref_history_lock);
5743#endif
5744}
5745EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
5746
5747static bool remote_i2c_read_ok(const struct i2c_msg msgs[], int num)
5748{
5749	int i;
5750
5751	if (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)
5752		return false;
5753
5754	for (i = 0; i < num - 1; i++) {
5755		if (msgs[i].flags & I2C_M_RD ||
5756		    msgs[i].len > 0xff)
5757			return false;
5758	}
5759
5760	return msgs[num - 1].flags & I2C_M_RD &&
5761		msgs[num - 1].len <= 0xff;
5762}
5763
5764static bool remote_i2c_write_ok(const struct i2c_msg msgs[], int num)
5765{
5766	int i;
5767
5768	for (i = 0; i < num - 1; i++) {
5769		if (msgs[i].flags & I2C_M_RD || !(msgs[i].flags & I2C_M_STOP) ||
5770		    msgs[i].len > 0xff)
5771			return false;
5772	}
5773
5774	return !(msgs[num - 1].flags & I2C_M_RD) && msgs[num - 1].len <= 0xff;
5775}
5776
5777static int drm_dp_mst_i2c_read(struct drm_dp_mst_branch *mstb,
5778			       struct drm_dp_mst_port *port,
5779			       struct i2c_msg *msgs, int num)
5780{
5781	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5782	unsigned int i;
5783	struct drm_dp_sideband_msg_req_body msg;
5784	struct drm_dp_sideband_msg_tx *txmsg = NULL;
5785	int ret;
5786
5787	memset(&msg, 0, sizeof(msg));
5788	msg.req_type = DP_REMOTE_I2C_READ;
5789	msg.u.i2c_read.num_transactions = num - 1;
5790	msg.u.i2c_read.port_number = port->port_num;
5791	for (i = 0; i < num - 1; i++) {
5792		msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
5793		msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
5794		msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
5795		msg.u.i2c_read.transactions[i].no_stop_bit = !(msgs[i].flags & I2C_M_STOP);
5796	}
5797	msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
5798	msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
5799
5800	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5801	if (!txmsg) {
5802		ret = -ENOMEM;
5803		goto out;
5804	}
5805
5806	txmsg->dst = mstb;
5807	drm_dp_encode_sideband_req(&msg, txmsg);
5808
5809	drm_dp_queue_down_tx(mgr, txmsg);
5810
5811	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5812	if (ret > 0) {
5813
5814		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5815			ret = -EREMOTEIO;
5816			goto out;
5817		}
5818		if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
5819			ret = -EIO;
5820			goto out;
5821		}
5822		memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
5823		ret = num;
5824	}
5825out:
5826	kfree(txmsg);
5827	return ret;
5828}
5829
5830static int drm_dp_mst_i2c_write(struct drm_dp_mst_branch *mstb,
5831				struct drm_dp_mst_port *port,
5832				struct i2c_msg *msgs, int num)
5833{
5834	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5835	unsigned int i;
5836	struct drm_dp_sideband_msg_req_body msg;
5837	struct drm_dp_sideband_msg_tx *txmsg = NULL;
5838	int ret;
5839
5840	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5841	if (!txmsg) {
5842		ret = -ENOMEM;
5843		goto out;
5844	}
5845	for (i = 0; i < num; i++) {
5846		memset(&msg, 0, sizeof(msg));
5847		msg.req_type = DP_REMOTE_I2C_WRITE;
5848		msg.u.i2c_write.port_number = port->port_num;
5849		msg.u.i2c_write.write_i2c_device_id = msgs[i].addr;
5850		msg.u.i2c_write.num_bytes = msgs[i].len;
5851		msg.u.i2c_write.bytes = msgs[i].buf;
5852
5853		memset(txmsg, 0, sizeof(*txmsg));
5854		txmsg->dst = mstb;
5855
5856		drm_dp_encode_sideband_req(&msg, txmsg);
5857		drm_dp_queue_down_tx(mgr, txmsg);
5858
5859		ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5860		if (ret > 0) {
5861			if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5862				ret = -EREMOTEIO;
5863				goto out;
5864			}
5865		} else {
5866			goto out;
5867		}
5868	}
5869	ret = num;
5870out:
5871	kfree(txmsg);
5872	return ret;
5873}
5874
5875/* I2C device */
5876static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter,
5877			       struct i2c_msg *msgs, int num)
5878{
5879	struct drm_dp_aux *aux = adapter->algo_data;
5880	struct drm_dp_mst_port *port =
5881		container_of(aux, struct drm_dp_mst_port, aux);
5882	struct drm_dp_mst_branch *mstb;
5883	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5884	int ret;
5885
5886	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
5887	if (!mstb)
5888		return -EREMOTEIO;
5889
5890	if (remote_i2c_read_ok(msgs, num)) {
5891		ret = drm_dp_mst_i2c_read(mstb, port, msgs, num);
5892	} else if (remote_i2c_write_ok(msgs, num)) {
5893		ret = drm_dp_mst_i2c_write(mstb, port, msgs, num);
5894	} else {
5895		drm_dbg_kms(mgr->dev, "Unsupported I2C transaction for MST device\n");
5896		ret = -EIO;
5897	}
5898
5899	drm_dp_mst_topology_put_mstb(mstb);
5900	return ret;
5901}
5902
5903static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
5904{
5905	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
5906	       I2C_FUNC_SMBUS_READ_BLOCK_DATA |
5907	       I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
5908	       I2C_FUNC_10BIT_ADDR;
5909}
5910
5911static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
5912	.functionality = drm_dp_mst_i2c_functionality,
5913	.master_xfer = drm_dp_mst_i2c_xfer,
5914};
5915
5916/**
5917 * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
5918 * @port: The port to add the I2C bus on
5919 *
5920 * Returns 0 on success or a negative error code on failure.
5921 */
5922static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port)
5923{
5924	struct drm_dp_aux *aux = &port->aux;
5925	struct device *parent_dev = port->mgr->dev->dev;
5926
5927	aux->ddc.algo = &drm_dp_mst_i2c_algo;
5928	aux->ddc.algo_data = aux;
5929	aux->ddc.retries = 3;
5930
5931	aux->ddc.owner = THIS_MODULE;
5932	/* FIXME: set the kdev of the port's connector as parent */
5933	aux->ddc.dev.parent = parent_dev;
5934	aux->ddc.dev.of_node = parent_dev->of_node;
5935
5936	strscpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
5937		sizeof(aux->ddc.name));
5938
5939	return i2c_add_adapter(&aux->ddc);
5940}
5941
5942/**
5943 * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
5944 * @port: The port to remove the I2C bus from
5945 */
5946static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port)
5947{
5948	i2c_del_adapter(&port->aux.ddc);
5949}
5950
5951/**
5952 * drm_dp_mst_is_virtual_dpcd() - Is the given port a virtual DP Peer Device
5953 * @port: The port to check
5954 *
5955 * A single physical MST hub object can be represented in the topology
5956 * by multiple branches, with virtual ports between those branches.
5957 *
5958 * As of DP1.4, An MST hub with internal (virtual) ports must expose
5959 * certain DPCD registers over those ports. See sections 2.6.1.1.1
5960 * and 2.6.1.1.2 of Display Port specification v1.4 for details.
5961 *
5962 * May acquire mgr->lock
5963 *
5964 * Returns:
5965 * true if the port is a virtual DP peer device, false otherwise
5966 */
5967static bool drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port *port)
5968{
5969	struct drm_dp_mst_port *downstream_port;
5970
5971	if (!port || port->dpcd_rev < DP_DPCD_REV_14)
5972		return false;
5973
5974	/* Virtual DP Sink (Internal Display Panel) */
5975	if (port->port_num >= 8)
5976		return true;
5977
5978	/* DP-to-HDMI Protocol Converter */
5979	if (port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV &&
5980	    !port->mcs &&
5981	    port->ldps)
5982		return true;
5983
5984	/* DP-to-DP */
5985	mutex_lock(&port->mgr->lock);
5986	if (port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
5987	    port->mstb &&
5988	    port->mstb->num_ports == 2) {
5989		list_for_each_entry(downstream_port, &port->mstb->ports, next) {
5990			if (downstream_port->pdt == DP_PEER_DEVICE_SST_SINK &&
5991			    !downstream_port->input) {
5992				mutex_unlock(&port->mgr->lock);
5993				return true;
5994			}
5995		}
5996	}
5997	mutex_unlock(&port->mgr->lock);
5998
5999	return false;
6000}
6001
6002/**
6003 * drm_dp_mst_dsc_aux_for_port() - Find the correct aux for DSC
6004 * @port: The port to check. A leaf of the MST tree with an attached display.
6005 *
6006 * Depending on the situation, DSC may be enabled via the endpoint aux,
6007 * the immediately upstream aux, or the connector's physical aux.
6008 *
6009 * This is both the correct aux to read DSC_CAPABILITY and the
6010 * correct aux to write DSC_ENABLED.
6011 *
6012 * This operation can be expensive (up to four aux reads), so
6013 * the caller should cache the return.
6014 *
6015 * Returns:
6016 * NULL if DSC cannot be enabled on this port, otherwise the aux device
6017 */
6018struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
6019{
6020	struct drm_dp_mst_port *immediate_upstream_port;
6021	struct drm_dp_aux *immediate_upstream_aux;
6022	struct drm_dp_mst_port *fec_port;
6023	struct drm_dp_desc desc = {};
6024	u8 endpoint_fec;
6025	u8 endpoint_dsc;
6026
6027	if (!port)
6028		return NULL;
6029
6030	if (port->parent->port_parent)
6031		immediate_upstream_port = port->parent->port_parent;
6032	else
6033		immediate_upstream_port = NULL;
6034
6035	fec_port = immediate_upstream_port;
6036	while (fec_port) {
6037		/*
6038		 * Each physical link (i.e. not a virtual port) between the
6039		 * output and the primary device must support FEC
6040		 */
6041		if (!drm_dp_mst_is_virtual_dpcd(fec_port) &&
6042		    !fec_port->fec_capable)
6043			return NULL;
6044
6045		fec_port = fec_port->parent->port_parent;
6046	}
6047
6048	/* DP-to-DP peer device */
6049	if (drm_dp_mst_is_virtual_dpcd(immediate_upstream_port)) {
6050		u8 upstream_dsc;
6051
6052		if (drm_dp_dpcd_read(&port->aux,
6053				     DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
6054			return NULL;
6055		if (drm_dp_dpcd_read(&port->aux,
6056				     DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
6057			return NULL;
6058		if (drm_dp_dpcd_read(&immediate_upstream_port->aux,
6059				     DP_DSC_SUPPORT, &upstream_dsc, 1) != 1)
6060			return NULL;
6061
6062		/* Enpoint decompression with DP-to-DP peer device */
6063		if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
6064		    (endpoint_fec & DP_FEC_CAPABLE) &&
6065		    (upstream_dsc & DP_DSC_PASSTHROUGH_IS_SUPPORTED)) {
6066			port->passthrough_aux = &immediate_upstream_port->aux;
6067			return &port->aux;
6068		}
6069
6070		/* Virtual DPCD decompression with DP-to-DP peer device */
6071		return &immediate_upstream_port->aux;
6072	}
6073
6074	/* Virtual DPCD decompression with DP-to-HDMI or Virtual DP Sink */
6075	if (drm_dp_mst_is_virtual_dpcd(port))
6076		return &port->aux;
6077
6078	/*
6079	 * Synaptics quirk
6080	 * Applies to ports for which:
6081	 * - Physical aux has Synaptics OUI
6082	 * - DPv1.4 or higher
6083	 * - Port is on primary branch device
6084	 * - Not a VGA adapter (DP_DWN_STRM_PORT_TYPE_ANALOG)
6085	 */
6086	if (immediate_upstream_port)
6087		immediate_upstream_aux = &immediate_upstream_port->aux;
6088	else
6089		immediate_upstream_aux = port->mgr->aux;
6090
6091	if (drm_dp_read_desc(immediate_upstream_aux, &desc, true))
6092		return NULL;
6093
6094	if (drm_dp_has_quirk(&desc, DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD)) {
6095		u8 dpcd_ext[DP_RECEIVER_CAP_SIZE];
6096
6097		if (drm_dp_read_dpcd_caps(immediate_upstream_aux, dpcd_ext) < 0)
6098			return NULL;
6099
6100		if (dpcd_ext[DP_DPCD_REV] >= DP_DPCD_REV_14 &&
6101		    ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT) &&
6102		    ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK)
6103		     != DP_DWN_STRM_PORT_TYPE_ANALOG)))
6104			return immediate_upstream_aux;
6105	}
6106
6107	/*
6108	 * The check below verifies if the MST sink
6109	 * connected to the GPU is capable of DSC -
6110	 * therefore the endpoint needs to be
6111	 * both DSC and FEC capable.
6112	 */
6113	if (drm_dp_dpcd_read(&port->aux,
6114	   DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
6115		return NULL;
6116	if (drm_dp_dpcd_read(&port->aux,
6117	   DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
6118		return NULL;
6119	if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
6120	   (endpoint_fec & DP_FEC_CAPABLE))
6121		return &port->aux;
6122
6123	return NULL;
6124}
6125EXPORT_SYMBOL(drm_dp_mst_dsc_aux_for_port);