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/drm_atomic.h>
  42#include <drm/drm_atomic_helper.h>
  43#include <drm/drm_dp_mst_helper.h>
  44#include <drm/drm_drv.h>
  45#include <drm/drm_print.h>
  46#include <drm/drm_probe_helper.h>
  47
  48#include "drm_crtc_helper_internal.h"
  49#include "drm_dp_mst_topology_internal.h"
  50
  51/**
  52 * DOC: dp mst helper
  53 *
  54 * These functions contain parts of the DisplayPort 1.2a MultiStream Transport
  55 * protocol. The helpers contain a topology manager and bandwidth manager.
  56 * The helpers encapsulate the sending and received of sideband msgs.
  57 */
  58struct drm_dp_pending_up_req {
  59	struct drm_dp_sideband_msg_hdr hdr;
  60	struct drm_dp_sideband_msg_req_body msg;
  61	struct list_head next;
  62};
  63
  64static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
  65				  char *buf);
  66
  67static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port);
  68
  69static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
  70				     int id,
  71				     struct drm_dp_payload *payload);
  72
  73static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
  74				 struct drm_dp_mst_port *port,
  75				 int offset, int size, u8 *bytes);
  76static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
  77				  struct drm_dp_mst_port *port,
  78				  int offset, int size, u8 *bytes);
  79
  80static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
  81				    struct drm_dp_mst_branch *mstb);
  82
  83static void
  84drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
  85				   struct drm_dp_mst_branch *mstb);
  86
  87static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
  88					   struct drm_dp_mst_branch *mstb,
  89					   struct drm_dp_mst_port *port);
  90static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
  91				 u8 *guid);
  92
  93static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
  94static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
  95static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
  96
  97static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
  98						 struct drm_dp_mst_branch *branch);
  99
 100#define DBG_PREFIX "[dp_mst]"
 101
 102#define DP_STR(x) [DP_ ## x] = #x
 103
 104static const char *drm_dp_mst_req_type_str(u8 req_type)
 105{
 106	static const char * const req_type_str[] = {
 107		DP_STR(GET_MSG_TRANSACTION_VERSION),
 108		DP_STR(LINK_ADDRESS),
 109		DP_STR(CONNECTION_STATUS_NOTIFY),
 110		DP_STR(ENUM_PATH_RESOURCES),
 111		DP_STR(ALLOCATE_PAYLOAD),
 112		DP_STR(QUERY_PAYLOAD),
 113		DP_STR(RESOURCE_STATUS_NOTIFY),
 114		DP_STR(CLEAR_PAYLOAD_ID_TABLE),
 115		DP_STR(REMOTE_DPCD_READ),
 116		DP_STR(REMOTE_DPCD_WRITE),
 117		DP_STR(REMOTE_I2C_READ),
 118		DP_STR(REMOTE_I2C_WRITE),
 119		DP_STR(POWER_UP_PHY),
 120		DP_STR(POWER_DOWN_PHY),
 121		DP_STR(SINK_EVENT_NOTIFY),
 122		DP_STR(QUERY_STREAM_ENC_STATUS),
 123	};
 124
 125	if (req_type >= ARRAY_SIZE(req_type_str) ||
 126	    !req_type_str[req_type])
 127		return "unknown";
 128
 129	return req_type_str[req_type];
 130}
 131
 132#undef DP_STR
 133#define DP_STR(x) [DP_NAK_ ## x] = #x
 134
 135static const char *drm_dp_mst_nak_reason_str(u8 nak_reason)
 136{
 137	static const char * const nak_reason_str[] = {
 138		DP_STR(WRITE_FAILURE),
 139		DP_STR(INVALID_READ),
 140		DP_STR(CRC_FAILURE),
 141		DP_STR(BAD_PARAM),
 142		DP_STR(DEFER),
 143		DP_STR(LINK_FAILURE),
 144		DP_STR(NO_RESOURCES),
 145		DP_STR(DPCD_FAIL),
 146		DP_STR(I2C_NAK),
 147		DP_STR(ALLOCATE_FAIL),
 148	};
 149
 150	if (nak_reason >= ARRAY_SIZE(nak_reason_str) ||
 151	    !nak_reason_str[nak_reason])
 152		return "unknown";
 153
 154	return nak_reason_str[nak_reason];
 155}
 156
 157#undef DP_STR
 158#define DP_STR(x) [DRM_DP_SIDEBAND_TX_ ## x] = #x
 159
 160static const char *drm_dp_mst_sideband_tx_state_str(int state)
 161{
 162	static const char * const sideband_reason_str[] = {
 163		DP_STR(QUEUED),
 164		DP_STR(START_SEND),
 165		DP_STR(SENT),
 166		DP_STR(RX),
 167		DP_STR(TIMEOUT),
 168	};
 169
 170	if (state >= ARRAY_SIZE(sideband_reason_str) ||
 171	    !sideband_reason_str[state])
 172		return "unknown";
 173
 174	return sideband_reason_str[state];
 175}
 176
 177static int
 178drm_dp_mst_rad_to_str(const u8 rad[8], u8 lct, char *out, size_t len)
 179{
 180	int i;
 181	u8 unpacked_rad[16];
 182
 183	for (i = 0; i < lct; i++) {
 184		if (i % 2)
 185			unpacked_rad[i] = rad[i / 2] >> 4;
 186		else
 187			unpacked_rad[i] = rad[i / 2] & BIT_MASK(4);
 188	}
 189
 190	/* TODO: Eventually add something to printk so we can format the rad
 191	 * like this: 1.2.3
 192	 */
 193	return snprintf(out, len, "%*phC", lct, unpacked_rad);
 194}
 195
 196/* sideband msg handling */
 197static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
 198{
 199	u8 bitmask = 0x80;
 200	u8 bitshift = 7;
 201	u8 array_index = 0;
 202	int number_of_bits = num_nibbles * 4;
 203	u8 remainder = 0;
 204
 205	while (number_of_bits != 0) {
 206		number_of_bits--;
 207		remainder <<= 1;
 208		remainder |= (data[array_index] & bitmask) >> bitshift;
 209		bitmask >>= 1;
 210		bitshift--;
 211		if (bitmask == 0) {
 212			bitmask = 0x80;
 213			bitshift = 7;
 214			array_index++;
 215		}
 216		if ((remainder & 0x10) == 0x10)
 217			remainder ^= 0x13;
 218	}
 219
 220	number_of_bits = 4;
 221	while (number_of_bits != 0) {
 222		number_of_bits--;
 223		remainder <<= 1;
 224		if ((remainder & 0x10) != 0)
 225			remainder ^= 0x13;
 226	}
 227
 228	return remainder;
 229}
 230
 231static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes)
 232{
 233	u8 bitmask = 0x80;
 234	u8 bitshift = 7;
 235	u8 array_index = 0;
 236	int number_of_bits = number_of_bytes * 8;
 237	u16 remainder = 0;
 238
 239	while (number_of_bits != 0) {
 240		number_of_bits--;
 241		remainder <<= 1;
 242		remainder |= (data[array_index] & bitmask) >> bitshift;
 243		bitmask >>= 1;
 244		bitshift--;
 245		if (bitmask == 0) {
 246			bitmask = 0x80;
 247			bitshift = 7;
 248			array_index++;
 249		}
 250		if ((remainder & 0x100) == 0x100)
 251			remainder ^= 0xd5;
 252	}
 253
 254	number_of_bits = 8;
 255	while (number_of_bits != 0) {
 256		number_of_bits--;
 257		remainder <<= 1;
 258		if ((remainder & 0x100) != 0)
 259			remainder ^= 0xd5;
 260	}
 261
 262	return remainder & 0xff;
 263}
 264static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr)
 265{
 266	u8 size = 3;
 267
 268	size += (hdr->lct / 2);
 269	return size;
 270}
 271
 272static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
 273					   u8 *buf, int *len)
 274{
 275	int idx = 0;
 276	int i;
 277	u8 crc4;
 278
 279	buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
 280	for (i = 0; i < (hdr->lct / 2); i++)
 281		buf[idx++] = hdr->rad[i];
 282	buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
 283		(hdr->msg_len & 0x3f);
 284	buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
 285
 286	crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
 287	buf[idx - 1] |= (crc4 & 0xf);
 288
 289	*len = idx;
 290}
 291
 292static bool drm_dp_decode_sideband_msg_hdr(const struct drm_dp_mst_topology_mgr *mgr,
 293					   struct drm_dp_sideband_msg_hdr *hdr,
 294					   u8 *buf, int buflen, u8 *hdrlen)
 295{
 296	u8 crc4;
 297	u8 len;
 298	int i;
 299	u8 idx;
 300
 301	if (buf[0] == 0)
 302		return false;
 303	len = 3;
 304	len += ((buf[0] & 0xf0) >> 4) / 2;
 305	if (len > buflen)
 306		return false;
 307	crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
 308
 309	if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
 310		drm_dbg_kms(mgr->dev, "crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
 311		return false;
 312	}
 313
 314	hdr->lct = (buf[0] & 0xf0) >> 4;
 315	hdr->lcr = (buf[0] & 0xf);
 316	idx = 1;
 317	for (i = 0; i < (hdr->lct / 2); i++)
 318		hdr->rad[i] = buf[idx++];
 319	hdr->broadcast = (buf[idx] >> 7) & 0x1;
 320	hdr->path_msg = (buf[idx] >> 6) & 0x1;
 321	hdr->msg_len = buf[idx] & 0x3f;
 322	idx++;
 323	hdr->somt = (buf[idx] >> 7) & 0x1;
 324	hdr->eomt = (buf[idx] >> 6) & 0x1;
 325	hdr->seqno = (buf[idx] >> 4) & 0x1;
 326	idx++;
 327	*hdrlen = idx;
 328	return true;
 329}
 330
 331void
 332drm_dp_encode_sideband_req(const struct drm_dp_sideband_msg_req_body *req,
 333			   struct drm_dp_sideband_msg_tx *raw)
 334{
 335	int idx = 0;
 336	int i;
 337	u8 *buf = raw->msg;
 338
 339	buf[idx++] = req->req_type & 0x7f;
 340
 341	switch (req->req_type) {
 342	case DP_ENUM_PATH_RESOURCES:
 343	case DP_POWER_DOWN_PHY:
 344	case DP_POWER_UP_PHY:
 345		buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
 346		idx++;
 347		break;
 348	case DP_ALLOCATE_PAYLOAD:
 349		buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
 350			(req->u.allocate_payload.number_sdp_streams & 0xf);
 351		idx++;
 352		buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
 353		idx++;
 354		buf[idx] = (req->u.allocate_payload.pbn >> 8);
 355		idx++;
 356		buf[idx] = (req->u.allocate_payload.pbn & 0xff);
 357		idx++;
 358		for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
 359			buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) |
 360				(req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
 361			idx++;
 362		}
 363		if (req->u.allocate_payload.number_sdp_streams & 1) {
 364			i = req->u.allocate_payload.number_sdp_streams - 1;
 365			buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
 366			idx++;
 367		}
 368		break;
 369	case DP_QUERY_PAYLOAD:
 370		buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
 371		idx++;
 372		buf[idx] = (req->u.query_payload.vcpi & 0x7f);
 373		idx++;
 374		break;
 375	case DP_REMOTE_DPCD_READ:
 376		buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
 377		buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
 378		idx++;
 379		buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
 380		idx++;
 381		buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
 382		idx++;
 383		buf[idx] = (req->u.dpcd_read.num_bytes);
 384		idx++;
 385		break;
 386
 387	case DP_REMOTE_DPCD_WRITE:
 388		buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
 389		buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
 390		idx++;
 391		buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
 392		idx++;
 393		buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
 394		idx++;
 395		buf[idx] = (req->u.dpcd_write.num_bytes);
 396		idx++;
 397		memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
 398		idx += req->u.dpcd_write.num_bytes;
 399		break;
 400	case DP_REMOTE_I2C_READ:
 401		buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
 402		buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
 403		idx++;
 404		for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
 405			buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
 406			idx++;
 407			buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
 408			idx++;
 409			memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes);
 410			idx += req->u.i2c_read.transactions[i].num_bytes;
 411
 412			buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 4;
 413			buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf);
 414			idx++;
 415		}
 416		buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
 417		idx++;
 418		buf[idx] = (req->u.i2c_read.num_bytes_read);
 419		idx++;
 420		break;
 421
 422	case DP_REMOTE_I2C_WRITE:
 423		buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
 424		idx++;
 425		buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
 426		idx++;
 427		buf[idx] = (req->u.i2c_write.num_bytes);
 428		idx++;
 429		memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
 430		idx += req->u.i2c_write.num_bytes;
 431		break;
 432	case DP_QUERY_STREAM_ENC_STATUS: {
 433		const struct drm_dp_query_stream_enc_status *msg;
 434
 435		msg = &req->u.enc_status;
 436		buf[idx] = msg->stream_id;
 437		idx++;
 438		memcpy(&buf[idx], msg->client_id, sizeof(msg->client_id));
 439		idx += sizeof(msg->client_id);
 440		buf[idx] = 0;
 441		buf[idx] |= FIELD_PREP(GENMASK(1, 0), msg->stream_event);
 442		buf[idx] |= msg->valid_stream_event ? BIT(2) : 0;
 443		buf[idx] |= FIELD_PREP(GENMASK(4, 3), msg->stream_behavior);
 444		buf[idx] |= msg->valid_stream_behavior ? BIT(5) : 0;
 445		idx++;
 446		}
 447		break;
 448	}
 449	raw->cur_len = idx;
 450}
 451EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_encode_sideband_req);
 452
 453/* Decode a sideband request we've encoded, mainly used for debugging */
 454int
 455drm_dp_decode_sideband_req(const struct drm_dp_sideband_msg_tx *raw,
 456			   struct drm_dp_sideband_msg_req_body *req)
 457{
 458	const u8 *buf = raw->msg;
 459	int i, idx = 0;
 460
 461	req->req_type = buf[idx++] & 0x7f;
 462	switch (req->req_type) {
 463	case DP_ENUM_PATH_RESOURCES:
 464	case DP_POWER_DOWN_PHY:
 465	case DP_POWER_UP_PHY:
 466		req->u.port_num.port_number = (buf[idx] >> 4) & 0xf;
 467		break;
 468	case DP_ALLOCATE_PAYLOAD:
 469		{
 470			struct drm_dp_allocate_payload *a =
 471				&req->u.allocate_payload;
 472
 473			a->number_sdp_streams = buf[idx] & 0xf;
 474			a->port_number = (buf[idx] >> 4) & 0xf;
 475
 476			WARN_ON(buf[++idx] & 0x80);
 477			a->vcpi = buf[idx] & 0x7f;
 478
 479			a->pbn = buf[++idx] << 8;
 480			a->pbn |= buf[++idx];
 481
 482			idx++;
 483			for (i = 0; i < a->number_sdp_streams; i++) {
 484				a->sdp_stream_sink[i] =
 485					(buf[idx + (i / 2)] >> ((i % 2) ? 0 : 4)) & 0xf;
 486			}
 487		}
 488		break;
 489	case DP_QUERY_PAYLOAD:
 490		req->u.query_payload.port_number = (buf[idx] >> 4) & 0xf;
 491		WARN_ON(buf[++idx] & 0x80);
 492		req->u.query_payload.vcpi = buf[idx] & 0x7f;
 493		break;
 494	case DP_REMOTE_DPCD_READ:
 495		{
 496			struct drm_dp_remote_dpcd_read *r = &req->u.dpcd_read;
 497
 498			r->port_number = (buf[idx] >> 4) & 0xf;
 499
 500			r->dpcd_address = (buf[idx] << 16) & 0xf0000;
 501			r->dpcd_address |= (buf[++idx] << 8) & 0xff00;
 502			r->dpcd_address |= buf[++idx] & 0xff;
 503
 504			r->num_bytes = buf[++idx];
 505		}
 506		break;
 507	case DP_REMOTE_DPCD_WRITE:
 508		{
 509			struct drm_dp_remote_dpcd_write *w =
 510				&req->u.dpcd_write;
 511
 512			w->port_number = (buf[idx] >> 4) & 0xf;
 513
 514			w->dpcd_address = (buf[idx] << 16) & 0xf0000;
 515			w->dpcd_address |= (buf[++idx] << 8) & 0xff00;
 516			w->dpcd_address |= buf[++idx] & 0xff;
 517
 518			w->num_bytes = buf[++idx];
 519
 520			w->bytes = kmemdup(&buf[++idx], w->num_bytes,
 521					   GFP_KERNEL);
 522			if (!w->bytes)
 523				return -ENOMEM;
 524		}
 525		break;
 526	case DP_REMOTE_I2C_READ:
 527		{
 528			struct drm_dp_remote_i2c_read *r = &req->u.i2c_read;
 529			struct drm_dp_remote_i2c_read_tx *tx;
 530			bool failed = false;
 531
 532			r->num_transactions = buf[idx] & 0x3;
 533			r->port_number = (buf[idx] >> 4) & 0xf;
 534			for (i = 0; i < r->num_transactions; i++) {
 535				tx = &r->transactions[i];
 536
 537				tx->i2c_dev_id = buf[++idx] & 0x7f;
 538				tx->num_bytes = buf[++idx];
 539				tx->bytes = kmemdup(&buf[++idx],
 540						    tx->num_bytes,
 541						    GFP_KERNEL);
 542				if (!tx->bytes) {
 543					failed = true;
 544					break;
 545				}
 546				idx += tx->num_bytes;
 547				tx->no_stop_bit = (buf[idx] >> 5) & 0x1;
 548				tx->i2c_transaction_delay = buf[idx] & 0xf;
 549			}
 550
 551			if (failed) {
 552				for (i = 0; i < r->num_transactions; i++) {
 553					tx = &r->transactions[i];
 554					kfree(tx->bytes);
 555				}
 556				return -ENOMEM;
 557			}
 558
 559			r->read_i2c_device_id = buf[++idx] & 0x7f;
 560			r->num_bytes_read = buf[++idx];
 561		}
 562		break;
 563	case DP_REMOTE_I2C_WRITE:
 564		{
 565			struct drm_dp_remote_i2c_write *w = &req->u.i2c_write;
 566
 567			w->port_number = (buf[idx] >> 4) & 0xf;
 568			w->write_i2c_device_id = buf[++idx] & 0x7f;
 569			w->num_bytes = buf[++idx];
 570			w->bytes = kmemdup(&buf[++idx], w->num_bytes,
 571					   GFP_KERNEL);
 572			if (!w->bytes)
 573				return -ENOMEM;
 574		}
 575		break;
 576	case DP_QUERY_STREAM_ENC_STATUS:
 577		req->u.enc_status.stream_id = buf[idx++];
 578		for (i = 0; i < sizeof(req->u.enc_status.client_id); i++)
 579			req->u.enc_status.client_id[i] = buf[idx++];
 580
 581		req->u.enc_status.stream_event = FIELD_GET(GENMASK(1, 0),
 582							   buf[idx]);
 583		req->u.enc_status.valid_stream_event = FIELD_GET(BIT(2),
 584								 buf[idx]);
 585		req->u.enc_status.stream_behavior = FIELD_GET(GENMASK(4, 3),
 586							      buf[idx]);
 587		req->u.enc_status.valid_stream_behavior = FIELD_GET(BIT(5),
 588								    buf[idx]);
 589		break;
 590	}
 591
 592	return 0;
 593}
 594EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_decode_sideband_req);
 595
 596void
 597drm_dp_dump_sideband_msg_req_body(const struct drm_dp_sideband_msg_req_body *req,
 598				  int indent, struct drm_printer *printer)
 599{
 600	int i;
 601
 602#define P(f, ...) drm_printf_indent(printer, indent, f, ##__VA_ARGS__)
 603	if (req->req_type == DP_LINK_ADDRESS) {
 604		/* No contents to print */
 605		P("type=%s\n", drm_dp_mst_req_type_str(req->req_type));
 606		return;
 607	}
 608
 609	P("type=%s contents:\n", drm_dp_mst_req_type_str(req->req_type));
 610	indent++;
 611
 612	switch (req->req_type) {
 613	case DP_ENUM_PATH_RESOURCES:
 614	case DP_POWER_DOWN_PHY:
 615	case DP_POWER_UP_PHY:
 616		P("port=%d\n", req->u.port_num.port_number);
 617		break;
 618	case DP_ALLOCATE_PAYLOAD:
 619		P("port=%d vcpi=%d pbn=%d sdp_streams=%d %*ph\n",
 620		  req->u.allocate_payload.port_number,
 621		  req->u.allocate_payload.vcpi, req->u.allocate_payload.pbn,
 622		  req->u.allocate_payload.number_sdp_streams,
 623		  req->u.allocate_payload.number_sdp_streams,
 624		  req->u.allocate_payload.sdp_stream_sink);
 625		break;
 626	case DP_QUERY_PAYLOAD:
 627		P("port=%d vcpi=%d\n",
 628		  req->u.query_payload.port_number,
 629		  req->u.query_payload.vcpi);
 630		break;
 631	case DP_REMOTE_DPCD_READ:
 632		P("port=%d dpcd_addr=%05x len=%d\n",
 633		  req->u.dpcd_read.port_number, req->u.dpcd_read.dpcd_address,
 634		  req->u.dpcd_read.num_bytes);
 635		break;
 636	case DP_REMOTE_DPCD_WRITE:
 637		P("port=%d addr=%05x len=%d: %*ph\n",
 638		  req->u.dpcd_write.port_number,
 639		  req->u.dpcd_write.dpcd_address,
 640		  req->u.dpcd_write.num_bytes, req->u.dpcd_write.num_bytes,
 641		  req->u.dpcd_write.bytes);
 642		break;
 643	case DP_REMOTE_I2C_READ:
 644		P("port=%d num_tx=%d id=%d size=%d:\n",
 645		  req->u.i2c_read.port_number,
 646		  req->u.i2c_read.num_transactions,
 647		  req->u.i2c_read.read_i2c_device_id,
 648		  req->u.i2c_read.num_bytes_read);
 649
 650		indent++;
 651		for (i = 0; i < req->u.i2c_read.num_transactions; i++) {
 652			const struct drm_dp_remote_i2c_read_tx *rtx =
 653				&req->u.i2c_read.transactions[i];
 654
 655			P("%d: id=%03d size=%03d no_stop_bit=%d tx_delay=%03d: %*ph\n",
 656			  i, rtx->i2c_dev_id, rtx->num_bytes,
 657			  rtx->no_stop_bit, rtx->i2c_transaction_delay,
 658			  rtx->num_bytes, rtx->bytes);
 659		}
 660		break;
 661	case DP_REMOTE_I2C_WRITE:
 662		P("port=%d id=%d size=%d: %*ph\n",
 663		  req->u.i2c_write.port_number,
 664		  req->u.i2c_write.write_i2c_device_id,
 665		  req->u.i2c_write.num_bytes, req->u.i2c_write.num_bytes,
 666		  req->u.i2c_write.bytes);
 667		break;
 668	case DP_QUERY_STREAM_ENC_STATUS:
 669		P("stream_id=%u client_id=%*ph stream_event=%x "
 670		  "valid_event=%d stream_behavior=%x valid_behavior=%d",
 671		  req->u.enc_status.stream_id,
 672		  (int)ARRAY_SIZE(req->u.enc_status.client_id),
 673		  req->u.enc_status.client_id, req->u.enc_status.stream_event,
 674		  req->u.enc_status.valid_stream_event,
 675		  req->u.enc_status.stream_behavior,
 676		  req->u.enc_status.valid_stream_behavior);
 677		break;
 678	default:
 679		P("???\n");
 680		break;
 681	}
 682#undef P
 683}
 684EXPORT_SYMBOL_FOR_TESTS_ONLY(drm_dp_dump_sideband_msg_req_body);
 685
 686static inline void
 687drm_dp_mst_dump_sideband_msg_tx(struct drm_printer *p,
 688				const struct drm_dp_sideband_msg_tx *txmsg)
 689{
 690	struct drm_dp_sideband_msg_req_body req;
 691	char buf[64];
 692	int ret;
 693	int i;
 694
 695	drm_dp_mst_rad_to_str(txmsg->dst->rad, txmsg->dst->lct, buf,
 696			      sizeof(buf));
 697	drm_printf(p, "txmsg cur_offset=%x cur_len=%x seqno=%x state=%s path_msg=%d dst=%s\n",
 698		   txmsg->cur_offset, txmsg->cur_len, txmsg->seqno,
 699		   drm_dp_mst_sideband_tx_state_str(txmsg->state),
 700		   txmsg->path_msg, buf);
 701
 702	ret = drm_dp_decode_sideband_req(txmsg, &req);
 703	if (ret) {
 704		drm_printf(p, "<failed to decode sideband req: %d>\n", ret);
 705		return;
 706	}
 707	drm_dp_dump_sideband_msg_req_body(&req, 1, p);
 708
 709	switch (req.req_type) {
 710	case DP_REMOTE_DPCD_WRITE:
 711		kfree(req.u.dpcd_write.bytes);
 712		break;
 713	case DP_REMOTE_I2C_READ:
 714		for (i = 0; i < req.u.i2c_read.num_transactions; i++)
 715			kfree(req.u.i2c_read.transactions[i].bytes);
 716		break;
 717	case DP_REMOTE_I2C_WRITE:
 718		kfree(req.u.i2c_write.bytes);
 719		break;
 720	}
 721}
 722
 723static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
 724{
 725	u8 crc4;
 726
 727	crc4 = drm_dp_msg_data_crc4(msg, len);
 728	msg[len] = crc4;
 729}
 730
 731static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep,
 732					 struct drm_dp_sideband_msg_tx *raw)
 733{
 734	int idx = 0;
 735	u8 *buf = raw->msg;
 736
 737	buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
 738
 739	raw->cur_len = idx;
 740}
 741
 742static int drm_dp_sideband_msg_set_header(struct drm_dp_sideband_msg_rx *msg,
 743					  struct drm_dp_sideband_msg_hdr *hdr,
 744					  u8 hdrlen)
 745{
 746	/*
 747	 * ignore out-of-order messages or messages that are part of a
 748	 * failed transaction
 749	 */
 750	if (!hdr->somt && !msg->have_somt)
 751		return false;
 752
 753	/* get length contained in this portion */
 754	msg->curchunk_idx = 0;
 755	msg->curchunk_len = hdr->msg_len;
 756	msg->curchunk_hdrlen = hdrlen;
 757
 758	/* we have already gotten an somt - don't bother parsing */
 759	if (hdr->somt && msg->have_somt)
 760		return false;
 761
 762	if (hdr->somt) {
 763		memcpy(&msg->initial_hdr, hdr,
 764		       sizeof(struct drm_dp_sideband_msg_hdr));
 765		msg->have_somt = true;
 766	}
 767	if (hdr->eomt)
 768		msg->have_eomt = true;
 769
 770	return true;
 771}
 772
 773/* this adds a chunk of msg to the builder to get the final msg */
 774static bool drm_dp_sideband_append_payload(struct drm_dp_sideband_msg_rx *msg,
 775					   u8 *replybuf, u8 replybuflen)
 776{
 777	u8 crc4;
 778
 779	memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
 780	msg->curchunk_idx += replybuflen;
 781
 782	if (msg->curchunk_idx >= msg->curchunk_len) {
 783		/* do CRC */
 784		crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
 785		if (crc4 != msg->chunk[msg->curchunk_len - 1])
 786			print_hex_dump(KERN_DEBUG, "wrong crc",
 787				       DUMP_PREFIX_NONE, 16, 1,
 788				       msg->chunk,  msg->curchunk_len, false);
 789		/* copy chunk into bigger msg */
 790		memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
 791		msg->curlen += msg->curchunk_len - 1;
 792	}
 793	return true;
 794}
 795
 796static bool drm_dp_sideband_parse_link_address(const struct drm_dp_mst_topology_mgr *mgr,
 797					       struct drm_dp_sideband_msg_rx *raw,
 798					       struct drm_dp_sideband_msg_reply_body *repmsg)
 799{
 800	int idx = 1;
 801	int i;
 802
 803	memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
 804	idx += 16;
 805	repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
 806	idx++;
 807	if (idx > raw->curlen)
 808		goto fail_len;
 809	for (i = 0; i < repmsg->u.link_addr.nports; i++) {
 810		if (raw->msg[idx] & 0x80)
 811			repmsg->u.link_addr.ports[i].input_port = 1;
 812
 813		repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7;
 814		repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
 815
 816		idx++;
 817		if (idx > raw->curlen)
 818			goto fail_len;
 819		repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
 820		repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
 821		if (repmsg->u.link_addr.ports[i].input_port == 0)
 822			repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
 823		idx++;
 824		if (idx > raw->curlen)
 825			goto fail_len;
 826		if (repmsg->u.link_addr.ports[i].input_port == 0) {
 827			repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
 828			idx++;
 829			if (idx > raw->curlen)
 830				goto fail_len;
 831			memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
 832			idx += 16;
 833			if (idx > raw->curlen)
 834				goto fail_len;
 835			repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf;
 836			repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf);
 837			idx++;
 838
 839		}
 840		if (idx > raw->curlen)
 841			goto fail_len;
 842	}
 843
 844	return true;
 845fail_len:
 846	DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 847	return false;
 848}
 849
 850static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw,
 851						   struct drm_dp_sideband_msg_reply_body *repmsg)
 852{
 853	int idx = 1;
 854
 855	repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
 856	idx++;
 857	if (idx > raw->curlen)
 858		goto fail_len;
 859	repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
 860	idx++;
 861	if (idx > raw->curlen)
 862		goto fail_len;
 863
 864	memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes);
 865	return true;
 866fail_len:
 867	DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 868	return false;
 869}
 870
 871static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw,
 872						      struct drm_dp_sideband_msg_reply_body *repmsg)
 873{
 874	int idx = 1;
 875
 876	repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
 877	idx++;
 878	if (idx > raw->curlen)
 879		goto fail_len;
 880	return true;
 881fail_len:
 882	DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
 883	return false;
 884}
 885
 886static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw,
 887						      struct drm_dp_sideband_msg_reply_body *repmsg)
 888{
 889	int idx = 1;
 890
 891	repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
 892	idx++;
 893	if (idx > raw->curlen)
 894		goto fail_len;
 895	repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
 896	idx++;
 897	/* TODO check */
 898	memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes);
 899	return true;
 900fail_len:
 901	DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen);
 902	return false;
 903}
 904
 905static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw,
 906							  struct drm_dp_sideband_msg_reply_body *repmsg)
 907{
 908	int idx = 1;
 909
 910	repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
 911	repmsg->u.path_resources.fec_capable = raw->msg[idx] & 0x1;
 912	idx++;
 913	if (idx > raw->curlen)
 914		goto fail_len;
 915	repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 916	idx += 2;
 917	if (idx > raw->curlen)
 918		goto fail_len;
 919	repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 920	idx += 2;
 921	if (idx > raw->curlen)
 922		goto fail_len;
 923	return true;
 924fail_len:
 925	DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen);
 926	return false;
 927}
 928
 929static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 930							  struct drm_dp_sideband_msg_reply_body *repmsg)
 931{
 932	int idx = 1;
 933
 934	repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 935	idx++;
 936	if (idx > raw->curlen)
 937		goto fail_len;
 938	repmsg->u.allocate_payload.vcpi = raw->msg[idx];
 939	idx++;
 940	if (idx > raw->curlen)
 941		goto fail_len;
 942	repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 943	idx += 2;
 944	if (idx > raw->curlen)
 945		goto fail_len;
 946	return true;
 947fail_len:
 948	DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen);
 949	return false;
 950}
 951
 952static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 953						    struct drm_dp_sideband_msg_reply_body *repmsg)
 954{
 955	int idx = 1;
 956
 957	repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 958	idx++;
 959	if (idx > raw->curlen)
 960		goto fail_len;
 961	repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
 962	idx += 2;
 963	if (idx > raw->curlen)
 964		goto fail_len;
 965	return true;
 966fail_len:
 967	DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen);
 968	return false;
 969}
 970
 971static bool drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx *raw,
 972						       struct drm_dp_sideband_msg_reply_body *repmsg)
 973{
 974	int idx = 1;
 975
 976	repmsg->u.port_number.port_number = (raw->msg[idx] >> 4) & 0xf;
 977	idx++;
 978	if (idx > raw->curlen) {
 979		DRM_DEBUG_KMS("power up/down phy parse length fail %d %d\n",
 980			      idx, raw->curlen);
 981		return false;
 982	}
 983	return true;
 984}
 985
 986static bool
 987drm_dp_sideband_parse_query_stream_enc_status(
 988				struct drm_dp_sideband_msg_rx *raw,
 989				struct drm_dp_sideband_msg_reply_body *repmsg)
 990{
 991	struct drm_dp_query_stream_enc_status_ack_reply *reply;
 992
 993	reply = &repmsg->u.enc_status;
 994
 995	reply->stream_id = raw->msg[3];
 996
 997	reply->reply_signed = raw->msg[2] & BIT(0);
 998
 999	/*
1000	 * NOTE: It's my impression from reading the spec that the below parsing
1001	 * is correct. However I noticed while testing with an HDCP 1.4 display
1002	 * through an HDCP 2.2 hub that only bit 3 was set. In that case, I
1003	 * would expect both bits to be set. So keep the parsing following the
1004	 * spec, but beware reality might not match the spec (at least for some
1005	 * configurations).
1006	 */
1007	reply->hdcp_1x_device_present = raw->msg[2] & BIT(4);
1008	reply->hdcp_2x_device_present = raw->msg[2] & BIT(3);
1009
1010	reply->query_capable_device_present = raw->msg[2] & BIT(5);
1011	reply->legacy_device_present = raw->msg[2] & BIT(6);
1012	reply->unauthorizable_device_present = raw->msg[2] & BIT(7);
1013
1014	reply->auth_completed = !!(raw->msg[1] & BIT(3));
1015	reply->encryption_enabled = !!(raw->msg[1] & BIT(4));
1016	reply->repeater_present = !!(raw->msg[1] & BIT(5));
1017	reply->state = (raw->msg[1] & GENMASK(7, 6)) >> 6;
1018
1019	return true;
1020}
1021
1022static bool drm_dp_sideband_parse_reply(const struct drm_dp_mst_topology_mgr *mgr,
1023					struct drm_dp_sideband_msg_rx *raw,
1024					struct drm_dp_sideband_msg_reply_body *msg)
1025{
1026	memset(msg, 0, sizeof(*msg));
1027	msg->reply_type = (raw->msg[0] & 0x80) >> 7;
1028	msg->req_type = (raw->msg[0] & 0x7f);
1029
1030	if (msg->reply_type == DP_SIDEBAND_REPLY_NAK) {
1031		memcpy(msg->u.nak.guid, &raw->msg[1], 16);
1032		msg->u.nak.reason = raw->msg[17];
1033		msg->u.nak.nak_data = raw->msg[18];
1034		return false;
1035	}
1036
1037	switch (msg->req_type) {
1038	case DP_LINK_ADDRESS:
1039		return drm_dp_sideband_parse_link_address(mgr, raw, msg);
1040	case DP_QUERY_PAYLOAD:
1041		return drm_dp_sideband_parse_query_payload_ack(raw, msg);
1042	case DP_REMOTE_DPCD_READ:
1043		return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
1044	case DP_REMOTE_DPCD_WRITE:
1045		return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
1046	case DP_REMOTE_I2C_READ:
1047		return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
1048	case DP_REMOTE_I2C_WRITE:
1049		return true; /* since there's nothing to parse */
1050	case DP_ENUM_PATH_RESOURCES:
1051		return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
1052	case DP_ALLOCATE_PAYLOAD:
1053		return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
1054	case DP_POWER_DOWN_PHY:
1055	case DP_POWER_UP_PHY:
1056		return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg);
1057	case DP_CLEAR_PAYLOAD_ID_TABLE:
1058		return true; /* since there's nothing to parse */
1059	case DP_QUERY_STREAM_ENC_STATUS:
1060		return drm_dp_sideband_parse_query_stream_enc_status(raw, msg);
1061	default:
1062		drm_err(mgr->dev, "Got unknown reply 0x%02x (%s)\n",
1063			msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1064		return false;
1065	}
1066}
1067
1068static bool
1069drm_dp_sideband_parse_connection_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1070					       struct drm_dp_sideband_msg_rx *raw,
1071					       struct drm_dp_sideband_msg_req_body *msg)
1072{
1073	int idx = 1;
1074
1075	msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1076	idx++;
1077	if (idx > raw->curlen)
1078		goto fail_len;
1079
1080	memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
1081	idx += 16;
1082	if (idx > raw->curlen)
1083		goto fail_len;
1084
1085	msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
1086	msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
1087	msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
1088	msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
1089	msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
1090	idx++;
1091	return true;
1092fail_len:
1093	drm_dbg_kms(mgr->dev, "connection status reply parse length fail %d %d\n",
1094		    idx, raw->curlen);
1095	return false;
1096}
1097
1098static bool drm_dp_sideband_parse_resource_status_notify(const struct drm_dp_mst_topology_mgr *mgr,
1099							 struct drm_dp_sideband_msg_rx *raw,
1100							 struct drm_dp_sideband_msg_req_body *msg)
1101{
1102	int idx = 1;
1103
1104	msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
1105	idx++;
1106	if (idx > raw->curlen)
1107		goto fail_len;
1108
1109	memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
1110	idx += 16;
1111	if (idx > raw->curlen)
1112		goto fail_len;
1113
1114	msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
1115	idx++;
1116	return true;
1117fail_len:
1118	drm_dbg_kms(mgr->dev, "resource status reply parse length fail %d %d\n", idx, raw->curlen);
1119	return false;
1120}
1121
1122static bool drm_dp_sideband_parse_req(const struct drm_dp_mst_topology_mgr *mgr,
1123				      struct drm_dp_sideband_msg_rx *raw,
1124				      struct drm_dp_sideband_msg_req_body *msg)
1125{
1126	memset(msg, 0, sizeof(*msg));
1127	msg->req_type = (raw->msg[0] & 0x7f);
1128
1129	switch (msg->req_type) {
1130	case DP_CONNECTION_STATUS_NOTIFY:
1131		return drm_dp_sideband_parse_connection_status_notify(mgr, raw, msg);
1132	case DP_RESOURCE_STATUS_NOTIFY:
1133		return drm_dp_sideband_parse_resource_status_notify(mgr, raw, msg);
1134	default:
1135		drm_err(mgr->dev, "Got unknown request 0x%02x (%s)\n",
1136			msg->req_type, drm_dp_mst_req_type_str(msg->req_type));
1137		return false;
1138	}
1139}
1140
1141static void build_dpcd_write(struct drm_dp_sideband_msg_tx *msg,
1142			     u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
1143{
1144	struct drm_dp_sideband_msg_req_body req;
1145
1146	req.req_type = DP_REMOTE_DPCD_WRITE;
1147	req.u.dpcd_write.port_number = port_num;
1148	req.u.dpcd_write.dpcd_address = offset;
1149	req.u.dpcd_write.num_bytes = num_bytes;
1150	req.u.dpcd_write.bytes = bytes;
1151	drm_dp_encode_sideband_req(&req, msg);
1152}
1153
1154static void build_link_address(struct drm_dp_sideband_msg_tx *msg)
1155{
1156	struct drm_dp_sideband_msg_req_body req;
1157
1158	req.req_type = DP_LINK_ADDRESS;
1159	drm_dp_encode_sideband_req(&req, msg);
1160}
1161
1162static void build_clear_payload_id_table(struct drm_dp_sideband_msg_tx *msg)
1163{
1164	struct drm_dp_sideband_msg_req_body req;
1165
1166	req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE;
1167	drm_dp_encode_sideband_req(&req, msg);
1168	msg->path_msg = true;
1169}
1170
1171static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg,
1172				     int port_num)
1173{
1174	struct drm_dp_sideband_msg_req_body req;
1175
1176	req.req_type = DP_ENUM_PATH_RESOURCES;
1177	req.u.port_num.port_number = port_num;
1178	drm_dp_encode_sideband_req(&req, msg);
1179	msg->path_msg = true;
1180	return 0;
1181}
1182
1183static void build_allocate_payload(struct drm_dp_sideband_msg_tx *msg,
1184				   int port_num,
1185				   u8 vcpi, uint16_t pbn,
1186				   u8 number_sdp_streams,
1187				   u8 *sdp_stream_sink)
1188{
1189	struct drm_dp_sideband_msg_req_body req;
1190
1191	memset(&req, 0, sizeof(req));
1192	req.req_type = DP_ALLOCATE_PAYLOAD;
1193	req.u.allocate_payload.port_number = port_num;
1194	req.u.allocate_payload.vcpi = vcpi;
1195	req.u.allocate_payload.pbn = pbn;
1196	req.u.allocate_payload.number_sdp_streams = number_sdp_streams;
1197	memcpy(req.u.allocate_payload.sdp_stream_sink, sdp_stream_sink,
1198		   number_sdp_streams);
1199	drm_dp_encode_sideband_req(&req, msg);
1200	msg->path_msg = true;
1201}
1202
1203static void build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
1204				   int port_num, bool power_up)
1205{
1206	struct drm_dp_sideband_msg_req_body req;
1207
1208	if (power_up)
1209		req.req_type = DP_POWER_UP_PHY;
1210	else
1211		req.req_type = DP_POWER_DOWN_PHY;
1212
1213	req.u.port_num.port_number = port_num;
1214	drm_dp_encode_sideband_req(&req, msg);
1215	msg->path_msg = true;
1216}
1217
1218static int
1219build_query_stream_enc_status(struct drm_dp_sideband_msg_tx *msg, u8 stream_id,
1220			      u8 *q_id)
1221{
1222	struct drm_dp_sideband_msg_req_body req;
1223
1224	req.req_type = DP_QUERY_STREAM_ENC_STATUS;
1225	req.u.enc_status.stream_id = stream_id;
1226	memcpy(req.u.enc_status.client_id, q_id,
1227	       sizeof(req.u.enc_status.client_id));
1228	req.u.enc_status.stream_event = 0;
1229	req.u.enc_status.valid_stream_event = false;
1230	req.u.enc_status.stream_behavior = 0;
1231	req.u.enc_status.valid_stream_behavior = false;
1232
1233	drm_dp_encode_sideband_req(&req, msg);
1234	return 0;
1235}
1236
1237static int drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr *mgr,
1238					struct drm_dp_vcpi *vcpi)
1239{
1240	int ret, vcpi_ret;
1241
1242	mutex_lock(&mgr->payload_lock);
1243	ret = find_first_zero_bit(&mgr->payload_mask, mgr->max_payloads + 1);
1244	if (ret > mgr->max_payloads) {
1245		ret = -EINVAL;
1246		drm_dbg_kms(mgr->dev, "out of payload ids %d\n", ret);
1247		goto out_unlock;
1248	}
1249
1250	vcpi_ret = find_first_zero_bit(&mgr->vcpi_mask, mgr->max_payloads + 1);
1251	if (vcpi_ret > mgr->max_payloads) {
1252		ret = -EINVAL;
1253		drm_dbg_kms(mgr->dev, "out of vcpi ids %d\n", ret);
1254		goto out_unlock;
1255	}
1256
1257	set_bit(ret, &mgr->payload_mask);
1258	set_bit(vcpi_ret, &mgr->vcpi_mask);
1259	vcpi->vcpi = vcpi_ret + 1;
1260	mgr->proposed_vcpis[ret - 1] = vcpi;
1261out_unlock:
1262	mutex_unlock(&mgr->payload_lock);
1263	return ret;
1264}
1265
1266static void drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr *mgr,
1267				      int vcpi)
1268{
1269	int i;
1270
1271	if (vcpi == 0)
1272		return;
1273
1274	mutex_lock(&mgr->payload_lock);
1275	drm_dbg_kms(mgr->dev, "putting payload %d\n", vcpi);
1276	clear_bit(vcpi - 1, &mgr->vcpi_mask);
1277
1278	for (i = 0; i < mgr->max_payloads; i++) {
1279		if (mgr->proposed_vcpis[i] &&
1280		    mgr->proposed_vcpis[i]->vcpi == vcpi) {
1281			mgr->proposed_vcpis[i] = NULL;
1282			clear_bit(i + 1, &mgr->payload_mask);
1283		}
1284	}
1285	mutex_unlock(&mgr->payload_lock);
1286}
1287
1288static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
1289			      struct drm_dp_sideband_msg_tx *txmsg)
1290{
1291	unsigned int state;
1292
1293	/*
1294	 * All updates to txmsg->state are protected by mgr->qlock, and the two
1295	 * cases we check here are terminal states. For those the barriers
1296	 * provided by the wake_up/wait_event pair are enough.
1297	 */
1298	state = READ_ONCE(txmsg->state);
1299	return (state == DRM_DP_SIDEBAND_TX_RX ||
1300		state == DRM_DP_SIDEBAND_TX_TIMEOUT);
1301}
1302
1303static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
1304				    struct drm_dp_sideband_msg_tx *txmsg)
1305{
1306	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1307	unsigned long wait_timeout = msecs_to_jiffies(4000);
1308	unsigned long wait_expires = jiffies + wait_timeout;
1309	int ret;
1310
1311	for (;;) {
1312		/*
1313		 * If the driver provides a way for this, change to
1314		 * poll-waiting for the MST reply interrupt if we didn't receive
1315		 * it for 50 msec. This would cater for cases where the HPD
1316		 * pulse signal got lost somewhere, even though the sink raised
1317		 * the corresponding MST interrupt correctly. One example is the
1318		 * Club 3D CAC-1557 TypeC -> DP adapter which for some reason
1319		 * filters out short pulses with a duration less than ~540 usec.
1320		 *
1321		 * The poll period is 50 msec to avoid missing an interrupt
1322		 * after the sink has cleared it (after a 110msec timeout
1323		 * since it raised the interrupt).
1324		 */
1325		ret = wait_event_timeout(mgr->tx_waitq,
1326					 check_txmsg_state(mgr, txmsg),
1327					 mgr->cbs->poll_hpd_irq ?
1328						msecs_to_jiffies(50) :
1329						wait_timeout);
1330
1331		if (ret || !mgr->cbs->poll_hpd_irq ||
1332		    time_after(jiffies, wait_expires))
1333			break;
1334
1335		mgr->cbs->poll_hpd_irq(mgr);
1336	}
1337
1338	mutex_lock(&mgr->qlock);
1339	if (ret > 0) {
1340		if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
1341			ret = -EIO;
1342			goto out;
1343		}
1344	} else {
1345		drm_dbg_kms(mgr->dev, "timedout msg send %p %d %d\n",
1346			    txmsg, txmsg->state, txmsg->seqno);
1347
1348		/* dump some state */
1349		ret = -EIO;
1350
1351		/* remove from q */
1352		if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
1353		    txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
1354		    txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
1355			list_del(&txmsg->next);
1356	}
1357out:
1358	if (unlikely(ret == -EIO) && drm_debug_enabled(DRM_UT_DP)) {
1359		struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1360
1361		drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
1362	}
1363	mutex_unlock(&mgr->qlock);
1364
1365	drm_dp_mst_kick_tx(mgr);
1366	return ret;
1367}
1368
1369static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
1370{
1371	struct drm_dp_mst_branch *mstb;
1372
1373	mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
1374	if (!mstb)
1375		return NULL;
1376
1377	mstb->lct = lct;
1378	if (lct > 1)
1379		memcpy(mstb->rad, rad, lct / 2);
1380	INIT_LIST_HEAD(&mstb->ports);
1381	kref_init(&mstb->topology_kref);
1382	kref_init(&mstb->malloc_kref);
1383	return mstb;
1384}
1385
1386static void drm_dp_free_mst_branch_device(struct kref *kref)
1387{
1388	struct drm_dp_mst_branch *mstb =
1389		container_of(kref, struct drm_dp_mst_branch, malloc_kref);
1390
1391	if (mstb->port_parent)
1392		drm_dp_mst_put_port_malloc(mstb->port_parent);
1393
1394	kfree(mstb);
1395}
1396
1397/**
1398 * DOC: Branch device and port refcounting
1399 *
1400 * Topology refcount overview
1401 * ~~~~~~~~~~~~~~~~~~~~~~~~~~
1402 *
1403 * The refcounting schemes for &struct drm_dp_mst_branch and &struct
1404 * drm_dp_mst_port are somewhat unusual. Both ports and branch devices have
1405 * two different kinds of refcounts: topology refcounts, and malloc refcounts.
1406 *
1407 * Topology refcounts are not exposed to drivers, and are handled internally
1408 * by the DP MST helpers. The helpers use them in order to prevent the
1409 * in-memory topology state from being changed in the middle of critical
1410 * operations like changing the internal state of payload allocations. This
1411 * means each branch and port will be considered to be connected to the rest
1412 * of the topology until its topology refcount reaches zero. Additionally,
1413 * for ports this means that their associated &struct drm_connector will stay
1414 * registered with userspace until the port's refcount reaches 0.
1415 *
1416 * Malloc refcount overview
1417 * ~~~~~~~~~~~~~~~~~~~~~~~~
1418 *
1419 * Malloc references are used to keep a &struct drm_dp_mst_port or &struct
1420 * drm_dp_mst_branch allocated even after all of its topology references have
1421 * been dropped, so that the driver or MST helpers can safely access each
1422 * branch's last known state before it was disconnected from the topology.
1423 * When the malloc refcount of a port or branch reaches 0, the memory
1424 * allocation containing the &struct drm_dp_mst_branch or &struct
1425 * drm_dp_mst_port respectively will be freed.
1426 *
1427 * For &struct drm_dp_mst_branch, malloc refcounts are not currently exposed
1428 * to drivers. As of writing this documentation, there are no drivers that
1429 * have a usecase for accessing &struct drm_dp_mst_branch outside of the MST
1430 * helpers. Exposing this API to drivers in a race-free manner would take more
1431 * tweaking of the refcounting scheme, however patches are welcome provided
1432 * there is a legitimate driver usecase for this.
1433 *
1434 * Refcount relationships in a topology
1435 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1436 *
1437 * Let's take a look at why the relationship between topology and malloc
1438 * refcounts is designed the way it is.
1439 *
1440 * .. kernel-figure:: dp-mst/topology-figure-1.dot
1441 *
1442 *    An example of topology and malloc refs in a DP MST topology with two
1443 *    active payloads. Topology refcount increments are indicated by solid
1444 *    lines, and malloc refcount increments are indicated by dashed lines.
1445 *    Each starts from the branch which incremented the refcount, and ends at
1446 *    the branch to which the refcount belongs to, i.e. the arrow points the
1447 *    same way as the C pointers used to reference a structure.
1448 *
1449 * As you can see in the above figure, every branch increments the topology
1450 * refcount of its children, and increments the malloc refcount of its
1451 * parent. Additionally, every payload increments the malloc refcount of its
1452 * assigned port by 1.
1453 *
1454 * So, what would happen if MSTB #3 from the above figure was unplugged from
1455 * the system, but the driver hadn't yet removed payload #2 from port #3? The
1456 * topology would start to look like the figure below.
1457 *
1458 * .. kernel-figure:: dp-mst/topology-figure-2.dot
1459 *
1460 *    Ports and branch devices which have been released from memory are
1461 *    colored grey, and references which have been removed are colored red.
1462 *
1463 * Whenever a port or branch device's topology refcount reaches zero, it will
1464 * decrement the topology refcounts of all its children, the malloc refcount
1465 * of its parent, and finally its own malloc refcount. For MSTB #4 and port
1466 * #4, this means they both have been disconnected from the topology and freed
1467 * from memory. But, because payload #2 is still holding a reference to port
1468 * #3, port #3 is removed from the topology but its &struct drm_dp_mst_port
1469 * is still accessible from memory. This also means port #3 has not yet
1470 * decremented the malloc refcount of MSTB #3, so its &struct
1471 * drm_dp_mst_branch will also stay allocated in memory until port #3's
1472 * malloc refcount reaches 0.
1473 *
1474 * This relationship is necessary because in order to release payload #2, we
1475 * need to be able to figure out the last relative of port #3 that's still
1476 * connected to the topology. In this case, we would travel up the topology as
1477 * shown below.
1478 *
1479 * .. kernel-figure:: dp-mst/topology-figure-3.dot
1480 *
1481 * And finally, remove payload #2 by communicating with port #2 through
1482 * sideband transactions.
1483 */
1484
1485/**
1486 * drm_dp_mst_get_mstb_malloc() - Increment the malloc refcount of a branch
1487 * device
1488 * @mstb: The &struct drm_dp_mst_branch to increment the malloc refcount of
1489 *
1490 * Increments &drm_dp_mst_branch.malloc_kref. When
1491 * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1492 * will be released and @mstb may no longer be used.
1493 *
1494 * See also: drm_dp_mst_put_mstb_malloc()
1495 */
1496static void
1497drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch *mstb)
1498{
1499	kref_get(&mstb->malloc_kref);
1500	drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref));
1501}
1502
1503/**
1504 * drm_dp_mst_put_mstb_malloc() - Decrement the malloc refcount of a branch
1505 * device
1506 * @mstb: The &struct drm_dp_mst_branch to decrement the malloc refcount of
1507 *
1508 * Decrements &drm_dp_mst_branch.malloc_kref. When
1509 * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1510 * will be released and @mstb may no longer be used.
1511 *
1512 * See also: drm_dp_mst_get_mstb_malloc()
1513 */
1514static void
1515drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch *mstb)
1516{
1517	drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref) - 1);
1518	kref_put(&mstb->malloc_kref, drm_dp_free_mst_branch_device);
1519}
1520
1521static void drm_dp_free_mst_port(struct kref *kref)
1522{
1523	struct drm_dp_mst_port *port =
1524		container_of(kref, struct drm_dp_mst_port, malloc_kref);
1525
1526	drm_dp_mst_put_mstb_malloc(port->parent);
1527	kfree(port);
1528}
1529
1530/**
1531 * drm_dp_mst_get_port_malloc() - Increment the malloc refcount of an MST port
1532 * @port: The &struct drm_dp_mst_port to increment the malloc refcount of
1533 *
1534 * Increments &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1535 * reaches 0, the memory allocation for @port will be released and @port may
1536 * no longer be used.
1537 *
1538 * Because @port could potentially be freed at any time by the DP MST helpers
1539 * if &drm_dp_mst_port.malloc_kref reaches 0, including during a call to this
1540 * function, drivers that which to make use of &struct drm_dp_mst_port should
1541 * ensure that they grab at least one main malloc reference to their MST ports
1542 * in &drm_dp_mst_topology_cbs.add_connector. This callback is called before
1543 * there is any chance for &drm_dp_mst_port.malloc_kref to reach 0.
1544 *
1545 * See also: drm_dp_mst_put_port_malloc()
1546 */
1547void
1548drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port)
1549{
1550	kref_get(&port->malloc_kref);
1551	drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref));
1552}
1553EXPORT_SYMBOL(drm_dp_mst_get_port_malloc);
1554
1555/**
1556 * drm_dp_mst_put_port_malloc() - Decrement the malloc refcount of an MST port
1557 * @port: The &struct drm_dp_mst_port to decrement the malloc refcount of
1558 *
1559 * Decrements &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1560 * reaches 0, the memory allocation for @port will be released and @port may
1561 * no longer be used.
1562 *
1563 * See also: drm_dp_mst_get_port_malloc()
1564 */
1565void
1566drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port)
1567{
1568	drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->malloc_kref) - 1);
1569	kref_put(&port->malloc_kref, drm_dp_free_mst_port);
1570}
1571EXPORT_SYMBOL(drm_dp_mst_put_port_malloc);
1572
1573#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
1574
1575#define STACK_DEPTH 8
1576
1577static noinline void
1578__topology_ref_save(struct drm_dp_mst_topology_mgr *mgr,
1579		    struct drm_dp_mst_topology_ref_history *history,
1580		    enum drm_dp_mst_topology_ref_type type)
1581{
1582	struct drm_dp_mst_topology_ref_entry *entry = NULL;
1583	depot_stack_handle_t backtrace;
1584	ulong stack_entries[STACK_DEPTH];
1585	uint n;
1586	int i;
1587
1588	n = stack_trace_save(stack_entries, ARRAY_SIZE(stack_entries), 1);
1589	backtrace = stack_depot_save(stack_entries, n, GFP_KERNEL);
1590	if (!backtrace)
1591		return;
1592
1593	/* Try to find an existing entry for this backtrace */
1594	for (i = 0; i < history->len; i++) {
1595		if (history->entries[i].backtrace == backtrace) {
1596			entry = &history->entries[i];
1597			break;
1598		}
1599	}
1600
1601	/* Otherwise add one */
1602	if (!entry) {
1603		struct drm_dp_mst_topology_ref_entry *new;
1604		int new_len = history->len + 1;
1605
1606		new = krealloc(history->entries, sizeof(*new) * new_len,
1607			       GFP_KERNEL);
1608		if (!new)
1609			return;
1610
1611		entry = &new[history->len];
1612		history->len = new_len;
1613		history->entries = new;
1614
1615		entry->backtrace = backtrace;
1616		entry->type = type;
1617		entry->count = 0;
1618	}
1619	entry->count++;
1620	entry->ts_nsec = ktime_get_ns();
1621}
1622
1623static int
1624topology_ref_history_cmp(const void *a, const void *b)
1625{
1626	const struct drm_dp_mst_topology_ref_entry *entry_a = a, *entry_b = b;
1627
1628	if (entry_a->ts_nsec > entry_b->ts_nsec)
1629		return 1;
1630	else if (entry_a->ts_nsec < entry_b->ts_nsec)
1631		return -1;
1632	else
1633		return 0;
1634}
1635
1636static inline const char *
1637topology_ref_type_to_str(enum drm_dp_mst_topology_ref_type type)
1638{
1639	if (type == DRM_DP_MST_TOPOLOGY_REF_GET)
1640		return "get";
1641	else
1642		return "put";
1643}
1644
1645static void
1646__dump_topology_ref_history(struct drm_dp_mst_topology_ref_history *history,
1647			    void *ptr, const char *type_str)
1648{
1649	struct drm_printer p = drm_debug_printer(DBG_PREFIX);
1650	char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
1651	int i;
1652
1653	if (!buf)
1654		return;
1655
1656	if (!history->len)
1657		goto out;
1658
1659	/* First, sort the list so that it goes from oldest to newest
1660	 * reference entry
1661	 */
1662	sort(history->entries, history->len, sizeof(*history->entries),
1663	     topology_ref_history_cmp, NULL);
1664
1665	drm_printf(&p, "%s (%p) topology count reached 0, dumping history:\n",
1666		   type_str, ptr);
1667
1668	for (i = 0; i < history->len; i++) {
1669		const struct drm_dp_mst_topology_ref_entry *entry =
1670			&history->entries[i];
1671		ulong *entries;
1672		uint nr_entries;
1673		u64 ts_nsec = entry->ts_nsec;
1674		u32 rem_nsec = do_div(ts_nsec, 1000000000);
1675
1676		nr_entries = stack_depot_fetch(entry->backtrace, &entries);
1677		stack_trace_snprint(buf, PAGE_SIZE, entries, nr_entries, 4);
1678
1679		drm_printf(&p, "  %d %ss (last at %5llu.%06u):\n%s",
1680			   entry->count,
1681			   topology_ref_type_to_str(entry->type),
1682			   ts_nsec, rem_nsec / 1000, buf);
1683	}
1684
1685	/* Now free the history, since this is the only time we expose it */
1686	kfree(history->entries);
1687out:
1688	kfree(buf);
1689}
1690
1691static __always_inline void
1692drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb)
1693{
1694	__dump_topology_ref_history(&mstb->topology_ref_history, mstb,
1695				    "MSTB");
1696}
1697
1698static __always_inline void
1699drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port)
1700{
1701	__dump_topology_ref_history(&port->topology_ref_history, port,
1702				    "Port");
1703}
1704
1705static __always_inline void
1706save_mstb_topology_ref(struct drm_dp_mst_branch *mstb,
1707		       enum drm_dp_mst_topology_ref_type type)
1708{
1709	__topology_ref_save(mstb->mgr, &mstb->topology_ref_history, type);
1710}
1711
1712static __always_inline void
1713save_port_topology_ref(struct drm_dp_mst_port *port,
1714		       enum drm_dp_mst_topology_ref_type type)
1715{
1716	__topology_ref_save(port->mgr, &port->topology_ref_history, type);
1717}
1718
1719static inline void
1720topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr)
1721{
1722	mutex_lock(&mgr->topology_ref_history_lock);
1723}
1724
1725static inline void
1726topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr)
1727{
1728	mutex_unlock(&mgr->topology_ref_history_lock);
1729}
1730#else
1731static inline void
1732topology_ref_history_lock(struct drm_dp_mst_topology_mgr *mgr) {}
1733static inline void
1734topology_ref_history_unlock(struct drm_dp_mst_topology_mgr *mgr) {}
1735static inline void
1736drm_dp_mst_dump_mstb_topology_history(struct drm_dp_mst_branch *mstb) {}
1737static inline void
1738drm_dp_mst_dump_port_topology_history(struct drm_dp_mst_port *port) {}
1739#define save_mstb_topology_ref(mstb, type)
1740#define save_port_topology_ref(port, type)
1741#endif
1742
1743static void drm_dp_destroy_mst_branch_device(struct kref *kref)
1744{
1745	struct drm_dp_mst_branch *mstb =
1746		container_of(kref, struct drm_dp_mst_branch, topology_kref);
1747	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1748
1749	drm_dp_mst_dump_mstb_topology_history(mstb);
1750
1751	INIT_LIST_HEAD(&mstb->destroy_next);
1752
1753	/*
1754	 * This can get called under mgr->mutex, so we need to perform the
1755	 * actual destruction of the mstb in another worker
1756	 */
1757	mutex_lock(&mgr->delayed_destroy_lock);
1758	list_add(&mstb->destroy_next, &mgr->destroy_branch_device_list);
1759	mutex_unlock(&mgr->delayed_destroy_lock);
1760	queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1761}
1762
1763/**
1764 * drm_dp_mst_topology_try_get_mstb() - Increment the topology refcount of a
1765 * branch device unless it's zero
1766 * @mstb: &struct drm_dp_mst_branch to increment the topology refcount of
1767 *
1768 * Attempts to grab a topology reference to @mstb, if it hasn't yet been
1769 * removed from the topology (e.g. &drm_dp_mst_branch.topology_kref has
1770 * reached 0). Holding a topology reference implies that a malloc reference
1771 * will be held to @mstb as long as the user holds the topology reference.
1772 *
1773 * Care should be taken to ensure that the user has at least one malloc
1774 * reference to @mstb. If you already have a topology reference to @mstb, you
1775 * should use drm_dp_mst_topology_get_mstb() instead.
1776 *
1777 * See also:
1778 * drm_dp_mst_topology_get_mstb()
1779 * drm_dp_mst_topology_put_mstb()
1780 *
1781 * Returns:
1782 * * 1: A topology reference was grabbed successfully
1783 * * 0: @port is no longer in the topology, no reference was grabbed
1784 */
1785static int __must_check
1786drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch *mstb)
1787{
1788	int ret;
1789
1790	topology_ref_history_lock(mstb->mgr);
1791	ret = kref_get_unless_zero(&mstb->topology_kref);
1792	if (ret) {
1793		drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1794		save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1795	}
1796
1797	topology_ref_history_unlock(mstb->mgr);
1798
1799	return ret;
1800}
1801
1802/**
1803 * drm_dp_mst_topology_get_mstb() - Increment the topology refcount of a
1804 * branch device
1805 * @mstb: The &struct drm_dp_mst_branch to increment the topology refcount of
1806 *
1807 * Increments &drm_dp_mst_branch.topology_refcount without checking whether or
1808 * not it's already reached 0. This is only valid to use in scenarios where
1809 * you are already guaranteed to have at least one active topology reference
1810 * to @mstb. Otherwise, drm_dp_mst_topology_try_get_mstb() must be used.
1811 *
1812 * See also:
1813 * drm_dp_mst_topology_try_get_mstb()
1814 * drm_dp_mst_topology_put_mstb()
1815 */
1816static void drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch *mstb)
1817{
1818	topology_ref_history_lock(mstb->mgr);
1819
1820	save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_GET);
1821	WARN_ON(kref_read(&mstb->topology_kref) == 0);
1822	kref_get(&mstb->topology_kref);
1823	drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1824
1825	topology_ref_history_unlock(mstb->mgr);
1826}
1827
1828/**
1829 * drm_dp_mst_topology_put_mstb() - release a topology reference to a branch
1830 * device
1831 * @mstb: The &struct drm_dp_mst_branch to release the topology reference from
1832 *
1833 * Releases a topology reference from @mstb by decrementing
1834 * &drm_dp_mst_branch.topology_kref.
1835 *
1836 * See also:
1837 * drm_dp_mst_topology_try_get_mstb()
1838 * drm_dp_mst_topology_get_mstb()
1839 */
1840static void
1841drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch *mstb)
1842{
1843	topology_ref_history_lock(mstb->mgr);
1844
1845	drm_dbg(mstb->mgr->dev, "mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref) - 1);
1846	save_mstb_topology_ref(mstb, DRM_DP_MST_TOPOLOGY_REF_PUT);
1847
1848	topology_ref_history_unlock(mstb->mgr);
1849	kref_put(&mstb->topology_kref, drm_dp_destroy_mst_branch_device);
1850}
1851
1852static void drm_dp_destroy_port(struct kref *kref)
1853{
1854	struct drm_dp_mst_port *port =
1855		container_of(kref, struct drm_dp_mst_port, topology_kref);
1856	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
1857
1858	drm_dp_mst_dump_port_topology_history(port);
1859
1860	/* There's nothing that needs locking to destroy an input port yet */
1861	if (port->input) {
1862		drm_dp_mst_put_port_malloc(port);
1863		return;
1864	}
1865
1866	kfree(port->cached_edid);
1867
1868	/*
1869	 * we can't destroy the connector here, as we might be holding the
1870	 * mode_config.mutex from an EDID retrieval
1871	 */
1872	mutex_lock(&mgr->delayed_destroy_lock);
1873	list_add(&port->next, &mgr->destroy_port_list);
1874	mutex_unlock(&mgr->delayed_destroy_lock);
1875	queue_work(mgr->delayed_destroy_wq, &mgr->delayed_destroy_work);
1876}
1877
1878/**
1879 * drm_dp_mst_topology_try_get_port() - Increment the topology refcount of a
1880 * port unless it's zero
1881 * @port: &struct drm_dp_mst_port to increment the topology refcount of
1882 *
1883 * Attempts to grab a topology reference to @port, if it hasn't yet been
1884 * removed from the topology (e.g. &drm_dp_mst_port.topology_kref has reached
1885 * 0). Holding a topology reference implies that a malloc reference will be
1886 * held to @port as long as the user holds the topology reference.
1887 *
1888 * Care should be taken to ensure that the user has at least one malloc
1889 * reference to @port. If you already have a topology reference to @port, you
1890 * should use drm_dp_mst_topology_get_port() instead.
1891 *
1892 * See also:
1893 * drm_dp_mst_topology_get_port()
1894 * drm_dp_mst_topology_put_port()
1895 *
1896 * Returns:
1897 * * 1: A topology reference was grabbed successfully
1898 * * 0: @port is no longer in the topology, no reference was grabbed
1899 */
1900static int __must_check
1901drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port *port)
1902{
1903	int ret;
1904
1905	topology_ref_history_lock(port->mgr);
1906	ret = kref_get_unless_zero(&port->topology_kref);
1907	if (ret) {
1908		drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1909		save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1910	}
1911
1912	topology_ref_history_unlock(port->mgr);
1913	return ret;
1914}
1915
1916/**
1917 * drm_dp_mst_topology_get_port() - Increment the topology refcount of a port
1918 * @port: The &struct drm_dp_mst_port to increment the topology refcount of
1919 *
1920 * Increments &drm_dp_mst_port.topology_refcount without checking whether or
1921 * not it's already reached 0. This is only valid to use in scenarios where
1922 * you are already guaranteed to have at least one active topology reference
1923 * to @port. Otherwise, drm_dp_mst_topology_try_get_port() must be used.
1924 *
1925 * See also:
1926 * drm_dp_mst_topology_try_get_port()
1927 * drm_dp_mst_topology_put_port()
1928 */
1929static void drm_dp_mst_topology_get_port(struct drm_dp_mst_port *port)
1930{
1931	topology_ref_history_lock(port->mgr);
1932
1933	WARN_ON(kref_read(&port->topology_kref) == 0);
1934	kref_get(&port->topology_kref);
1935	drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref));
1936	save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_GET);
1937
1938	topology_ref_history_unlock(port->mgr);
1939}
1940
1941/**
1942 * drm_dp_mst_topology_put_port() - release a topology reference to a port
1943 * @port: The &struct drm_dp_mst_port to release the topology reference from
1944 *
1945 * Releases a topology reference from @port by decrementing
1946 * &drm_dp_mst_port.topology_kref.
1947 *
1948 * See also:
1949 * drm_dp_mst_topology_try_get_port()
1950 * drm_dp_mst_topology_get_port()
1951 */
1952static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port)
1953{
1954	topology_ref_history_lock(port->mgr);
1955
1956	drm_dbg(port->mgr->dev, "port %p (%d)\n", port, kref_read(&port->topology_kref) - 1);
1957	save_port_topology_ref(port, DRM_DP_MST_TOPOLOGY_REF_PUT);
1958
1959	topology_ref_history_unlock(port->mgr);
1960	kref_put(&port->topology_kref, drm_dp_destroy_port);
1961}
1962
1963static struct drm_dp_mst_branch *
1964drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch *mstb,
1965					      struct drm_dp_mst_branch *to_find)
1966{
1967	struct drm_dp_mst_port *port;
1968	struct drm_dp_mst_branch *rmstb;
1969
1970	if (to_find == mstb)
1971		return mstb;
1972
1973	list_for_each_entry(port, &mstb->ports, next) {
1974		if (port->mstb) {
1975			rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1976			    port->mstb, to_find);
1977			if (rmstb)
1978				return rmstb;
1979		}
1980	}
1981	return NULL;
1982}
1983
1984static struct drm_dp_mst_branch *
1985drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr *mgr,
1986				       struct drm_dp_mst_branch *mstb)
1987{
1988	struct drm_dp_mst_branch *rmstb = NULL;
1989
1990	mutex_lock(&mgr->lock);
1991	if (mgr->mst_primary) {
1992		rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1993		    mgr->mst_primary, mstb);
1994
1995		if (rmstb && !drm_dp_mst_topology_try_get_mstb(rmstb))
1996			rmstb = NULL;
1997	}
1998	mutex_unlock(&mgr->lock);
1999	return rmstb;
2000}
2001
2002static struct drm_dp_mst_port *
2003drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch *mstb,
2004					      struct drm_dp_mst_port *to_find)
2005{
2006	struct drm_dp_mst_port *port, *mport;
2007
2008	list_for_each_entry(port, &mstb->ports, next) {
2009		if (port == to_find)
2010			return port;
2011
2012		if (port->mstb) {
2013			mport = drm_dp_mst_topology_get_port_validated_locked(
2014			    port->mstb, to_find);
2015			if (mport)
2016				return mport;
2017		}
2018	}
2019	return NULL;
2020}
2021
2022static struct drm_dp_mst_port *
2023drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr *mgr,
2024				       struct drm_dp_mst_port *port)
2025{
2026	struct drm_dp_mst_port *rport = NULL;
2027
2028	mutex_lock(&mgr->lock);
2029	if (mgr->mst_primary) {
2030		rport = drm_dp_mst_topology_get_port_validated_locked(
2031		    mgr->mst_primary, port);
2032
2033		if (rport && !drm_dp_mst_topology_try_get_port(rport))
2034			rport = NULL;
2035	}
2036	mutex_unlock(&mgr->lock);
2037	return rport;
2038}
2039
2040static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
2041{
2042	struct drm_dp_mst_port *port;
2043	int ret;
2044
2045	list_for_each_entry(port, &mstb->ports, next) {
2046		if (port->port_num == port_num) {
2047			ret = drm_dp_mst_topology_try_get_port(port);
2048			return ret ? port : NULL;
2049		}
2050	}
2051
2052	return NULL;
2053}
2054
2055/*
2056 * calculate a new RAD for this MST branch device
2057 * if parent has an LCT of 2 then it has 1 nibble of RAD,
2058 * if parent has an LCT of 3 then it has 2 nibbles of RAD,
2059 */
2060static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
2061				 u8 *rad)
2062{
2063	int parent_lct = port->parent->lct;
2064	int shift = 4;
2065	int idx = (parent_lct - 1) / 2;
2066
2067	if (parent_lct > 1) {
2068		memcpy(rad, port->parent->rad, idx + 1);
2069		shift = (parent_lct % 2) ? 4 : 0;
2070	} else
2071		rad[0] = 0;
2072
2073	rad[idx] |= port->port_num << shift;
2074	return parent_lct + 1;
2075}
2076
2077static bool drm_dp_mst_is_end_device(u8 pdt, bool mcs)
2078{
2079	switch (pdt) {
2080	case DP_PEER_DEVICE_DP_LEGACY_CONV:
2081	case DP_PEER_DEVICE_SST_SINK:
2082		return true;
2083	case DP_PEER_DEVICE_MST_BRANCHING:
2084		/* For sst branch device */
2085		if (!mcs)
2086			return true;
2087
2088		return false;
2089	}
2090	return true;
2091}
2092
2093static int
2094drm_dp_port_set_pdt(struct drm_dp_mst_port *port, u8 new_pdt,
2095		    bool new_mcs)
2096{
2097	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2098	struct drm_dp_mst_branch *mstb;
2099	u8 rad[8], lct;
2100	int ret = 0;
2101
2102	if (port->pdt == new_pdt && port->mcs == new_mcs)
2103		return 0;
2104
2105	/* Teardown the old pdt, if there is one */
2106	if (port->pdt != DP_PEER_DEVICE_NONE) {
2107		if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2108			/*
2109			 * If the new PDT would also have an i2c bus,
2110			 * don't bother with reregistering it
2111			 */
2112			if (new_pdt != DP_PEER_DEVICE_NONE &&
2113			    drm_dp_mst_is_end_device(new_pdt, new_mcs)) {
2114				port->pdt = new_pdt;
2115				port->mcs = new_mcs;
2116				return 0;
2117			}
2118
2119			/* remove i2c over sideband */
2120			drm_dp_mst_unregister_i2c_bus(port);
2121		} else {
2122			mutex_lock(&mgr->lock);
2123			drm_dp_mst_topology_put_mstb(port->mstb);
2124			port->mstb = NULL;
2125			mutex_unlock(&mgr->lock);
2126		}
2127	}
2128
2129	port->pdt = new_pdt;
2130	port->mcs = new_mcs;
2131
2132	if (port->pdt != DP_PEER_DEVICE_NONE) {
2133		if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
2134			/* add i2c over sideband */
2135			ret = drm_dp_mst_register_i2c_bus(port);
2136		} else {
2137			lct = drm_dp_calculate_rad(port, rad);
2138			mstb = drm_dp_add_mst_branch_device(lct, rad);
2139			if (!mstb) {
2140				ret = -ENOMEM;
2141				drm_err(mgr->dev, "Failed to create MSTB for port %p", port);
2142				goto out;
2143			}
2144
2145			mutex_lock(&mgr->lock);
2146			port->mstb = mstb;
2147			mstb->mgr = port->mgr;
2148			mstb->port_parent = port;
2149
2150			/*
2151			 * Make sure this port's memory allocation stays
2152			 * around until its child MSTB releases it
2153			 */
2154			drm_dp_mst_get_port_malloc(port);
2155			mutex_unlock(&mgr->lock);
2156
2157			/* And make sure we send a link address for this */
2158			ret = 1;
2159		}
2160	}
2161
2162out:
2163	if (ret < 0)
2164		port->pdt = DP_PEER_DEVICE_NONE;
2165	return ret;
2166}
2167
2168/**
2169 * drm_dp_mst_dpcd_read() - read a series of bytes from the DPCD via sideband
2170 * @aux: Fake sideband AUX CH
2171 * @offset: address of the (first) register to read
2172 * @buffer: buffer to store the register values
2173 * @size: number of bytes in @buffer
2174 *
2175 * Performs the same functionality for remote devices via
2176 * sideband messaging as drm_dp_dpcd_read() does for local
2177 * devices via actual AUX CH.
2178 *
2179 * Return: Number of bytes read, or negative error code on failure.
2180 */
2181ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
2182			     unsigned int offset, void *buffer, size_t size)
2183{
2184	struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2185						    aux);
2186
2187	return drm_dp_send_dpcd_read(port->mgr, port,
2188				     offset, size, buffer);
2189}
2190
2191/**
2192 * drm_dp_mst_dpcd_write() - write a series of bytes to the DPCD via sideband
2193 * @aux: Fake sideband AUX CH
2194 * @offset: address of the (first) register to write
2195 * @buffer: buffer containing the values to write
2196 * @size: number of bytes in @buffer
2197 *
2198 * Performs the same functionality for remote devices via
2199 * sideband messaging as drm_dp_dpcd_write() does for local
2200 * devices via actual AUX CH.
2201 *
2202 * Return: number of bytes written on success, negative error code on failure.
2203 */
2204ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
2205			      unsigned int offset, void *buffer, size_t size)
2206{
2207	struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
2208						    aux);
2209
2210	return drm_dp_send_dpcd_write(port->mgr, port,
2211				      offset, size, buffer);
2212}
2213
2214static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
2215{
2216	int ret = 0;
2217
2218	memcpy(mstb->guid, guid, 16);
2219
2220	if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
2221		if (mstb->port_parent) {
2222			ret = drm_dp_send_dpcd_write(mstb->mgr,
2223						     mstb->port_parent,
2224						     DP_GUID, 16, mstb->guid);
2225		} else {
2226			ret = drm_dp_dpcd_write(mstb->mgr->aux,
2227						DP_GUID, mstb->guid, 16);
2228		}
2229	}
2230
2231	if (ret < 16 && ret > 0)
2232		return -EPROTO;
2233
2234	return ret == 16 ? 0 : ret;
2235}
2236
2237static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
2238				int pnum,
2239				char *proppath,
2240				size_t proppath_size)
2241{
2242	int i;
2243	char temp[8];
2244
2245	snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
2246	for (i = 0; i < (mstb->lct - 1); i++) {
2247		int shift = (i % 2) ? 0 : 4;
2248		int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
2249
2250		snprintf(temp, sizeof(temp), "-%d", port_num);
2251		strlcat(proppath, temp, proppath_size);
2252	}
2253	snprintf(temp, sizeof(temp), "-%d", pnum);
2254	strlcat(proppath, temp, proppath_size);
2255}
2256
2257/**
2258 * drm_dp_mst_connector_late_register() - Late MST connector registration
2259 * @connector: The MST connector
2260 * @port: The MST port for this connector
2261 *
2262 * Helper to register the remote aux device for this MST port. Drivers should
2263 * call this from their mst connector's late_register hook to enable MST aux
2264 * devices.
2265 *
2266 * Return: 0 on success, negative error code on failure.
2267 */
2268int drm_dp_mst_connector_late_register(struct drm_connector *connector,
2269				       struct drm_dp_mst_port *port)
2270{
2271	drm_dbg_kms(port->mgr->dev, "registering %s remote bus for %s\n",
2272		    port->aux.name, connector->kdev->kobj.name);
2273
2274	port->aux.dev = connector->kdev;
2275	return drm_dp_aux_register_devnode(&port->aux);
2276}
2277EXPORT_SYMBOL(drm_dp_mst_connector_late_register);
2278
2279/**
2280 * drm_dp_mst_connector_early_unregister() - Early MST connector unregistration
2281 * @connector: The MST connector
2282 * @port: The MST port for this connector
2283 *
2284 * Helper to unregister the remote aux device for this MST port, registered by
2285 * drm_dp_mst_connector_late_register(). Drivers should call this from their mst
2286 * connector's early_unregister hook.
2287 */
2288void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
2289					   struct drm_dp_mst_port *port)
2290{
2291	drm_dbg_kms(port->mgr->dev, "unregistering %s remote bus for %s\n",
2292		    port->aux.name, connector->kdev->kobj.name);
2293	drm_dp_aux_unregister_devnode(&port->aux);
2294}
2295EXPORT_SYMBOL(drm_dp_mst_connector_early_unregister);
2296
2297static void
2298drm_dp_mst_port_add_connector(struct drm_dp_mst_branch *mstb,
2299			      struct drm_dp_mst_port *port)
2300{
2301	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
2302	char proppath[255];
2303	int ret;
2304
2305	build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
2306	port->connector = mgr->cbs->add_connector(mgr, port, proppath);
2307	if (!port->connector) {
2308		ret = -ENOMEM;
2309		goto error;
2310	}
2311
2312	if (port->pdt != DP_PEER_DEVICE_NONE &&
2313	    drm_dp_mst_is_end_device(port->pdt, port->mcs) &&
2314	    port->port_num >= DP_MST_LOGICAL_PORT_0)
2315		port->cached_edid = drm_get_edid(port->connector,
2316						 &port->aux.ddc);
2317
2318	drm_connector_register(port->connector);
2319	return;
2320
2321error:
2322	drm_err(mgr->dev, "Failed to create connector for port %p: %d\n", port, ret);
2323}
2324
2325/*
2326 * Drop a topology reference, and unlink the port from the in-memory topology
2327 * layout
2328 */
2329static void
2330drm_dp_mst_topology_unlink_port(struct drm_dp_mst_topology_mgr *mgr,
2331				struct drm_dp_mst_port *port)
2332{
2333	mutex_lock(&mgr->lock);
2334	port->parent->num_ports--;
2335	list_del(&port->next);
2336	mutex_unlock(&mgr->lock);
2337	drm_dp_mst_topology_put_port(port);
2338}
2339
2340static struct drm_dp_mst_port *
2341drm_dp_mst_add_port(struct drm_device *dev,
2342		    struct drm_dp_mst_topology_mgr *mgr,
2343		    struct drm_dp_mst_branch *mstb, u8 port_number)
2344{
2345	struct drm_dp_mst_port *port = kzalloc(sizeof(*port), GFP_KERNEL);
2346
2347	if (!port)
2348		return NULL;
2349
2350	kref_init(&port->topology_kref);
2351	kref_init(&port->malloc_kref);
2352	port->parent = mstb;
2353	port->port_num = port_number;
2354	port->mgr = mgr;
2355	port->aux.name = "DPMST";
2356	port->aux.dev = dev->dev;
2357	port->aux.is_remote = true;
2358
2359	/* initialize the MST downstream port's AUX crc work queue */
2360	port->aux.drm_dev = dev;
2361	drm_dp_remote_aux_init(&port->aux);
2362
2363	/*
2364	 * Make sure the memory allocation for our parent branch stays
2365	 * around until our own memory allocation is released
2366	 */
2367	drm_dp_mst_get_mstb_malloc(mstb);
2368
2369	return port;
2370}
2371
2372static int
2373drm_dp_mst_handle_link_address_port(struct drm_dp_mst_branch *mstb,
2374				    struct drm_device *dev,
2375				    struct drm_dp_link_addr_reply_port *port_msg)
2376{
2377	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2378	struct drm_dp_mst_port *port;
2379	int old_ddps = 0, ret;
2380	u8 new_pdt = DP_PEER_DEVICE_NONE;
2381	bool new_mcs = 0;
2382	bool created = false, send_link_addr = false, changed = false;
2383
2384	port = drm_dp_get_port(mstb, port_msg->port_number);
2385	if (!port) {
2386		port = drm_dp_mst_add_port(dev, mgr, mstb,
2387					   port_msg->port_number);
2388		if (!port)
2389			return -ENOMEM;
2390		created = true;
2391		changed = true;
2392	} else if (!port->input && port_msg->input_port && port->connector) {
2393		/* Since port->connector can't be changed here, we create a
2394		 * new port if input_port changes from 0 to 1
2395		 */
2396		drm_dp_mst_topology_unlink_port(mgr, port);
2397		drm_dp_mst_topology_put_port(port);
2398		port = drm_dp_mst_add_port(dev, mgr, mstb,
2399					   port_msg->port_number);
2400		if (!port)
2401			return -ENOMEM;
2402		changed = true;
2403		created = true;
2404	} else if (port->input && !port_msg->input_port) {
2405		changed = true;
2406	} else if (port->connector) {
2407		/* We're updating a port that's exposed to userspace, so do it
2408		 * under lock
2409		 */
2410		drm_modeset_lock(&mgr->base.lock, NULL);
2411
2412		old_ddps = port->ddps;
2413		changed = port->ddps != port_msg->ddps ||
2414			(port->ddps &&
2415			 (port->ldps != port_msg->legacy_device_plug_status ||
2416			  port->dpcd_rev != port_msg->dpcd_revision ||
2417			  port->mcs != port_msg->mcs ||
2418			  port->pdt != port_msg->peer_device_type ||
2419			  port->num_sdp_stream_sinks !=
2420			  port_msg->num_sdp_stream_sinks));
2421	}
2422
2423	port->input = port_msg->input_port;
2424	if (!port->input)
2425		new_pdt = port_msg->peer_device_type;
2426	new_mcs = port_msg->mcs;
2427	port->ddps = port_msg->ddps;
2428	port->ldps = port_msg->legacy_device_plug_status;
2429	port->dpcd_rev = port_msg->dpcd_revision;
2430	port->num_sdp_streams = port_msg->num_sdp_streams;
2431	port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
2432
2433	/* manage mstb port lists with mgr lock - take a reference
2434	   for this list */
2435	if (created) {
2436		mutex_lock(&mgr->lock);
2437		drm_dp_mst_topology_get_port(port);
2438		list_add(&port->next, &mstb->ports);
2439		mstb->num_ports++;
2440		mutex_unlock(&mgr->lock);
2441	}
2442
2443	/*
2444	 * Reprobe PBN caps on both hotplug, and when re-probing the link
2445	 * for our parent mstb
2446	 */
2447	if (old_ddps != port->ddps || !created) {
2448		if (port->ddps && !port->input) {
2449			ret = drm_dp_send_enum_path_resources(mgr, mstb,
2450							      port);
2451			if (ret == 1)
2452				changed = true;
2453		} else {
2454			port->full_pbn = 0;
2455		}
2456	}
2457
2458	ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2459	if (ret == 1) {
2460		send_link_addr = true;
2461	} else if (ret < 0) {
2462		drm_err(dev, "Failed to change PDT on port %p: %d\n", port, ret);
2463		goto fail;
2464	}
2465
2466	/*
2467	 * If this port wasn't just created, then we're reprobing because
2468	 * we're coming out of suspend. In this case, always resend the link
2469	 * address if there's an MSTB on this port
2470	 */
2471	if (!created && port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
2472	    port->mcs)
2473		send_link_addr = true;
2474
2475	if (port->connector)
2476		drm_modeset_unlock(&mgr->base.lock);
2477	else if (!port->input)
2478		drm_dp_mst_port_add_connector(mstb, port);
2479
2480	if (send_link_addr && port->mstb) {
2481		ret = drm_dp_send_link_address(mgr, port->mstb);
2482		if (ret == 1) /* MSTB below us changed */
2483			changed = true;
2484		else if (ret < 0)
2485			goto fail_put;
2486	}
2487
2488	/* put reference to this port */
2489	drm_dp_mst_topology_put_port(port);
2490	return changed;
2491
2492fail:
2493	drm_dp_mst_topology_unlink_port(mgr, port);
2494	if (port->connector)
2495		drm_modeset_unlock(&mgr->base.lock);
2496fail_put:
2497	drm_dp_mst_topology_put_port(port);
2498	return ret;
2499}
2500
2501static void
2502drm_dp_mst_handle_conn_stat(struct drm_dp_mst_branch *mstb,
2503			    struct drm_dp_connection_status_notify *conn_stat)
2504{
2505	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
2506	struct drm_dp_mst_port *port;
2507	int old_ddps, ret;
2508	u8 new_pdt;
2509	bool new_mcs;
2510	bool dowork = false, create_connector = false;
2511
2512	port = drm_dp_get_port(mstb, conn_stat->port_number);
2513	if (!port)
2514		return;
2515
2516	if (port->connector) {
2517		if (!port->input && conn_stat->input_port) {
2518			/*
2519			 * We can't remove a connector from an already exposed
2520			 * port, so just throw the port out and make sure we
2521			 * reprobe the link address of it's parent MSTB
2522			 */
2523			drm_dp_mst_topology_unlink_port(mgr, port);
2524			mstb->link_address_sent = false;
2525			dowork = true;
2526			goto out;
2527		}
2528
2529		/* Locking is only needed if the port's exposed to userspace */
2530		drm_modeset_lock(&mgr->base.lock, NULL);
2531	} else if (port->input && !conn_stat->input_port) {
2532		create_connector = true;
2533		/* Reprobe link address so we get num_sdp_streams */
2534		mstb->link_address_sent = false;
2535		dowork = true;
2536	}
2537
2538	old_ddps = port->ddps;
2539	port->input = conn_stat->input_port;
2540	port->ldps = conn_stat->legacy_device_plug_status;
2541	port->ddps = conn_stat->displayport_device_plug_status;
2542
2543	if (old_ddps != port->ddps) {
2544		if (port->ddps && !port->input)
2545			drm_dp_send_enum_path_resources(mgr, mstb, port);
2546		else
2547			port->full_pbn = 0;
2548	}
2549
2550	new_pdt = port->input ? DP_PEER_DEVICE_NONE : conn_stat->peer_device_type;
2551	new_mcs = conn_stat->message_capability_status;
2552	ret = drm_dp_port_set_pdt(port, new_pdt, new_mcs);
2553	if (ret == 1) {
2554		dowork = true;
2555	} else if (ret < 0) {
2556		drm_err(mgr->dev, "Failed to change PDT for port %p: %d\n", port, ret);
2557		dowork = false;
2558	}
2559
2560	if (port->connector)
2561		drm_modeset_unlock(&mgr->base.lock);
2562	else if (create_connector)
2563		drm_dp_mst_port_add_connector(mstb, port);
2564
2565out:
2566	drm_dp_mst_topology_put_port(port);
2567	if (dowork)
2568		queue_work(system_long_wq, &mstb->mgr->work);
2569}
2570
2571static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
2572							       u8 lct, u8 *rad)
2573{
2574	struct drm_dp_mst_branch *mstb;
2575	struct drm_dp_mst_port *port;
2576	int i, ret;
2577	/* find the port by iterating down */
2578
2579	mutex_lock(&mgr->lock);
2580	mstb = mgr->mst_primary;
2581
2582	if (!mstb)
2583		goto out;
2584
2585	for (i = 0; i < lct - 1; i++) {
2586		int shift = (i % 2) ? 0 : 4;
2587		int port_num = (rad[i / 2] >> shift) & 0xf;
2588
2589		list_for_each_entry(port, &mstb->ports, next) {
2590			if (port->port_num == port_num) {
2591				mstb = port->mstb;
2592				if (!mstb) {
2593					drm_err(mgr->dev,
2594						"failed to lookup MSTB with lct %d, rad %02x\n",
2595						lct, rad[0]);
2596					goto out;
2597				}
2598
2599				break;
2600			}
2601		}
2602	}
2603	ret = drm_dp_mst_topology_try_get_mstb(mstb);
2604	if (!ret)
2605		mstb = NULL;
2606out:
2607	mutex_unlock(&mgr->lock);
2608	return mstb;
2609}
2610
2611static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
2612	struct drm_dp_mst_branch *mstb,
2613	const uint8_t *guid)
2614{
2615	struct drm_dp_mst_branch *found_mstb;
2616	struct drm_dp_mst_port *port;
2617
2618	if (memcmp(mstb->guid, guid, 16) == 0)
2619		return mstb;
2620
2621
2622	list_for_each_entry(port, &mstb->ports, next) {
2623		if (!port->mstb)
2624			continue;
2625
2626		found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid);
2627
2628		if (found_mstb)
2629			return found_mstb;
2630	}
2631
2632	return NULL;
2633}
2634
2635static struct drm_dp_mst_branch *
2636drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr *mgr,
2637				     const uint8_t *guid)
2638{
2639	struct drm_dp_mst_branch *mstb;
2640	int ret;
2641
2642	/* find the port by iterating down */
2643	mutex_lock(&mgr->lock);
2644
2645	mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
2646	if (mstb) {
2647		ret = drm_dp_mst_topology_try_get_mstb(mstb);
2648		if (!ret)
2649			mstb = NULL;
2650	}
2651
2652	mutex_unlock(&mgr->lock);
2653	return mstb;
2654}
2655
2656static int drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2657					       struct drm_dp_mst_branch *mstb)
2658{
2659	struct drm_dp_mst_port *port;
2660	int ret;
2661	bool changed = false;
2662
2663	if (!mstb->link_address_sent) {
2664		ret = drm_dp_send_link_address(mgr, mstb);
2665		if (ret == 1)
2666			changed = true;
2667		else if (ret < 0)
2668			return ret;
2669	}
2670
2671	list_for_each_entry(port, &mstb->ports, next) {
2672		struct drm_dp_mst_branch *mstb_child = NULL;
2673
2674		if (port->input || !port->ddps)
2675			continue;
2676
2677		if (port->mstb)
2678			mstb_child = drm_dp_mst_topology_get_mstb_validated(
2679			    mgr, port->mstb);
2680
2681		if (mstb_child) {
2682			ret = drm_dp_check_and_send_link_address(mgr,
2683								 mstb_child);
2684			drm_dp_mst_topology_put_mstb(mstb_child);
2685			if (ret == 1)
2686				changed = true;
2687			else if (ret < 0)
2688				return ret;
2689		}
2690	}
2691
2692	return changed;
2693}
2694
2695static void drm_dp_mst_link_probe_work(struct work_struct *work)
2696{
2697	struct drm_dp_mst_topology_mgr *mgr =
2698		container_of(work, struct drm_dp_mst_topology_mgr, work);
2699	struct drm_device *dev = mgr->dev;
2700	struct drm_dp_mst_branch *mstb;
2701	int ret;
2702	bool clear_payload_id_table;
2703
2704	mutex_lock(&mgr->probe_lock);
2705
2706	mutex_lock(&mgr->lock);
2707	clear_payload_id_table = !mgr->payload_id_table_cleared;
2708	mgr->payload_id_table_cleared = true;
2709
2710	mstb = mgr->mst_primary;
2711	if (mstb) {
2712		ret = drm_dp_mst_topology_try_get_mstb(mstb);
2713		if (!ret)
2714			mstb = NULL;
2715	}
2716	mutex_unlock(&mgr->lock);
2717	if (!mstb) {
2718		mutex_unlock(&mgr->probe_lock);
2719		return;
2720	}
2721
2722	/*
2723	 * Certain branch devices seem to incorrectly report an available_pbn
2724	 * of 0 on downstream sinks, even after clearing the
2725	 * DP_PAYLOAD_ALLOCATE_* registers in
2726	 * drm_dp_mst_topology_mgr_set_mst(). Namely, the CableMatters USB-C
2727	 * 2x DP hub. Sending a CLEAR_PAYLOAD_ID_TABLE message seems to make
2728	 * things work again.
2729	 */
2730	if (clear_payload_id_table) {
2731		drm_dbg_kms(dev, "Clearing payload ID table\n");
2732		drm_dp_send_clear_payload_id_table(mgr, mstb);
2733	}
2734
2735	ret = drm_dp_check_and_send_link_address(mgr, mstb);
2736	drm_dp_mst_topology_put_mstb(mstb);
2737
2738	mutex_unlock(&mgr->probe_lock);
2739	if (ret > 0)
2740		drm_kms_helper_hotplug_event(dev);
2741}
2742
2743static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
2744				 u8 *guid)
2745{
2746	u64 salt;
2747
2748	if (memchr_inv(guid, 0, 16))
2749		return true;
2750
2751	salt = get_jiffies_64();
2752
2753	memcpy(&guid[0], &salt, sizeof(u64));
2754	memcpy(&guid[8], &salt, sizeof(u64));
2755
2756	return false;
2757}
2758
2759static void build_dpcd_read(struct drm_dp_sideband_msg_tx *msg,
2760			    u8 port_num, u32 offset, u8 num_bytes)
2761{
2762	struct drm_dp_sideband_msg_req_body req;
2763
2764	req.req_type = DP_REMOTE_DPCD_READ;
2765	req.u.dpcd_read.port_number = port_num;
2766	req.u.dpcd_read.dpcd_address = offset;
2767	req.u.dpcd_read.num_bytes = num_bytes;
2768	drm_dp_encode_sideband_req(&req, msg);
2769}
2770
2771static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
2772				    bool up, u8 *msg, int len)
2773{
2774	int ret;
2775	int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
2776	int tosend, total, offset;
2777	int retries = 0;
2778
2779retry:
2780	total = len;
2781	offset = 0;
2782	do {
2783		tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
2784
2785		ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
2786					&msg[offset],
2787					tosend);
2788		if (ret != tosend) {
2789			if (ret == -EIO && retries < 5) {
2790				retries++;
2791				goto retry;
2792			}
2793			drm_dbg_kms(mgr->dev, "failed to dpcd write %d %d\n", tosend, ret);
2794
2795			return -EIO;
2796		}
2797		offset += tosend;
2798		total -= tosend;
2799	} while (total > 0);
2800	return 0;
2801}
2802
2803static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
2804				  struct drm_dp_sideband_msg_tx *txmsg)
2805{
2806	struct drm_dp_mst_branch *mstb = txmsg->dst;
2807	u8 req_type;
2808
2809	req_type = txmsg->msg[0] & 0x7f;
2810	if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
2811		req_type == DP_RESOURCE_STATUS_NOTIFY ||
2812		req_type == DP_CLEAR_PAYLOAD_ID_TABLE)
2813		hdr->broadcast = 1;
2814	else
2815		hdr->broadcast = 0;
2816	hdr->path_msg = txmsg->path_msg;
2817	if (hdr->broadcast) {
2818		hdr->lct = 1;
2819		hdr->lcr = 6;
2820	} else {
2821		hdr->lct = mstb->lct;
2822		hdr->lcr = mstb->lct - 1;
2823	}
2824
2825	memcpy(hdr->rad, mstb->rad, hdr->lct / 2);
2826
2827	return 0;
2828}
2829/*
2830 * process a single block of the next message in the sideband queue
2831 */
2832static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
2833				   struct drm_dp_sideband_msg_tx *txmsg,
2834				   bool up)
2835{
2836	u8 chunk[48];
2837	struct drm_dp_sideband_msg_hdr hdr;
2838	int len, space, idx, tosend;
2839	int ret;
2840
2841	if (txmsg->state == DRM_DP_SIDEBAND_TX_SENT)
2842		return 0;
2843
2844	memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
2845
2846	if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED)
2847		txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
2848
2849	/* make hdr from dst mst */
2850	ret = set_hdr_from_dst_qlock(&hdr, txmsg);
2851	if (ret < 0)
2852		return ret;
2853
2854	/* amount left to send in this message */
2855	len = txmsg->cur_len - txmsg->cur_offset;
2856
2857	/* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
2858	space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
2859
2860	tosend = min(len, space);
2861	if (len == txmsg->cur_len)
2862		hdr.somt = 1;
2863	if (space >= len)
2864		hdr.eomt = 1;
2865
2866
2867	hdr.msg_len = tosend + 1;
2868	drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
2869	memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
2870	/* add crc at end */
2871	drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
2872	idx += tosend + 1;
2873
2874	ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
2875	if (ret) {
2876		if (drm_debug_enabled(DRM_UT_DP)) {
2877			struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2878
2879			drm_printf(&p, "sideband msg failed to send\n");
2880			drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2881		}
2882		return ret;
2883	}
2884
2885	txmsg->cur_offset += tosend;
2886	if (txmsg->cur_offset == txmsg->cur_len) {
2887		txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
2888		return 1;
2889	}
2890	return 0;
2891}
2892
2893static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
2894{
2895	struct drm_dp_sideband_msg_tx *txmsg;
2896	int ret;
2897
2898	WARN_ON(!mutex_is_locked(&mgr->qlock));
2899
2900	/* construct a chunk from the first msg in the tx_msg queue */
2901	if (list_empty(&mgr->tx_msg_downq))
2902		return;
2903
2904	txmsg = list_first_entry(&mgr->tx_msg_downq,
2905				 struct drm_dp_sideband_msg_tx, next);
2906	ret = process_single_tx_qlock(mgr, txmsg, false);
2907	if (ret < 0) {
2908		drm_dbg_kms(mgr->dev, "failed to send msg in q %d\n", ret);
2909		list_del(&txmsg->next);
2910		txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
2911		wake_up_all(&mgr->tx_waitq);
2912	}
2913}
2914
2915static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
2916				 struct drm_dp_sideband_msg_tx *txmsg)
2917{
2918	mutex_lock(&mgr->qlock);
2919	list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
2920
2921	if (drm_debug_enabled(DRM_UT_DP)) {
2922		struct drm_printer p = drm_debug_printer(DBG_PREFIX);
2923
2924		drm_dp_mst_dump_sideband_msg_tx(&p, txmsg);
2925	}
2926
2927	if (list_is_singular(&mgr->tx_msg_downq))
2928		process_single_down_tx_qlock(mgr);
2929	mutex_unlock(&mgr->qlock);
2930}
2931
2932static void
2933drm_dp_dump_link_address(const struct drm_dp_mst_topology_mgr *mgr,
2934			 struct drm_dp_link_address_ack_reply *reply)
2935{
2936	struct drm_dp_link_addr_reply_port *port_reply;
2937	int i;
2938
2939	for (i = 0; i < reply->nports; i++) {
2940		port_reply = &reply->ports[i];
2941		drm_dbg_kms(mgr->dev,
2942			    "port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n",
2943			    i,
2944			    port_reply->input_port,
2945			    port_reply->peer_device_type,
2946			    port_reply->port_number,
2947			    port_reply->dpcd_revision,
2948			    port_reply->mcs,
2949			    port_reply->ddps,
2950			    port_reply->legacy_device_plug_status,
2951			    port_reply->num_sdp_streams,
2952			    port_reply->num_sdp_stream_sinks);
2953	}
2954}
2955
2956static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2957				     struct drm_dp_mst_branch *mstb)
2958{
2959	struct drm_dp_sideband_msg_tx *txmsg;
2960	struct drm_dp_link_address_ack_reply *reply;
2961	struct drm_dp_mst_port *port, *tmp;
2962	int i, ret, port_mask = 0;
2963	bool changed = false;
2964
2965	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2966	if (!txmsg)
2967		return -ENOMEM;
2968
2969	txmsg->dst = mstb;
2970	build_link_address(txmsg);
2971
2972	mstb->link_address_sent = true;
2973	drm_dp_queue_down_tx(mgr, txmsg);
2974
2975	/* FIXME: Actually do some real error handling here */
2976	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2977	if (ret <= 0) {
2978		drm_err(mgr->dev, "Sending link address failed with %d\n", ret);
2979		goto out;
2980	}
2981	if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
2982		drm_err(mgr->dev, "link address NAK received\n");
2983		ret = -EIO;
2984		goto out;
2985	}
2986
2987	reply = &txmsg->reply.u.link_addr;
2988	drm_dbg_kms(mgr->dev, "link address reply: %d\n", reply->nports);
2989	drm_dp_dump_link_address(mgr, reply);
2990
2991	ret = drm_dp_check_mstb_guid(mstb, reply->guid);
2992	if (ret) {
2993		char buf[64];
2994
2995		drm_dp_mst_rad_to_str(mstb->rad, mstb->lct, buf, sizeof(buf));
2996		drm_err(mgr->dev, "GUID check on %s failed: %d\n", buf, ret);
2997		goto out;
2998	}
2999
3000	for (i = 0; i < reply->nports; i++) {
3001		port_mask |= BIT(reply->ports[i].port_number);
3002		ret = drm_dp_mst_handle_link_address_port(mstb, mgr->dev,
3003							  &reply->ports[i]);
3004		if (ret == 1)
3005			changed = true;
3006		else if (ret < 0)
3007			goto out;
3008	}
3009
3010	/* Prune any ports that are currently a part of mstb in our in-memory
3011	 * topology, but were not seen in this link address. Usually this
3012	 * means that they were removed while the topology was out of sync,
3013	 * e.g. during suspend/resume
3014	 */
3015	mutex_lock(&mgr->lock);
3016	list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
3017		if (port_mask & BIT(port->port_num))
3018			continue;
3019
3020		drm_dbg_kms(mgr->dev, "port %d was not in link address, removing\n",
3021			    port->port_num);
3022		list_del(&port->next);
3023		drm_dp_mst_topology_put_port(port);
3024		changed = true;
3025	}
3026	mutex_unlock(&mgr->lock);
3027
3028out:
3029	if (ret <= 0)
3030		mstb->link_address_sent = false;
3031	kfree(txmsg);
3032	return ret < 0 ? ret : changed;
3033}
3034
3035static void
3036drm_dp_send_clear_payload_id_table(struct drm_dp_mst_topology_mgr *mgr,
3037				   struct drm_dp_mst_branch *mstb)
3038{
3039	struct drm_dp_sideband_msg_tx *txmsg;
3040	int ret;
3041
3042	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3043	if (!txmsg)
3044		return;
3045
3046	txmsg->dst = mstb;
3047	build_clear_payload_id_table(txmsg);
3048
3049	drm_dp_queue_down_tx(mgr, txmsg);
3050
3051	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3052	if (ret > 0 && txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3053		drm_dbg_kms(mgr->dev, "clear payload table id nak received\n");
3054
3055	kfree(txmsg);
3056}
3057
3058static int
3059drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
3060				struct drm_dp_mst_branch *mstb,
3061				struct drm_dp_mst_port *port)
3062{
3063	struct drm_dp_enum_path_resources_ack_reply *path_res;
3064	struct drm_dp_sideband_msg_tx *txmsg;
3065	int ret;
3066
3067	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3068	if (!txmsg)
3069		return -ENOMEM;
3070
3071	txmsg->dst = mstb;
3072	build_enum_path_resources(txmsg, port->port_num);
3073
3074	drm_dp_queue_down_tx(mgr, txmsg);
3075
3076	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3077	if (ret > 0) {
3078		ret = 0;
3079		path_res = &txmsg->reply.u.path_resources;
3080
3081		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3082			drm_dbg_kms(mgr->dev, "enum path resources nak received\n");
3083		} else {
3084			if (port->port_num != path_res->port_number)
3085				DRM_ERROR("got incorrect port in response\n");
3086
3087			drm_dbg_kms(mgr->dev, "enum path resources %d: %d %d\n",
3088				    path_res->port_number,
3089				    path_res->full_payload_bw_number,
3090				    path_res->avail_payload_bw_number);
3091
3092			/*
3093			 * If something changed, make sure we send a
3094			 * hotplug
3095			 */
3096			if (port->full_pbn != path_res->full_payload_bw_number ||
3097			    port->fec_capable != path_res->fec_capable)
3098				ret = 1;
3099
3100			port->full_pbn = path_res->full_payload_bw_number;
3101			port->fec_capable = path_res->fec_capable;
3102		}
3103	}
3104
3105	kfree(txmsg);
3106	return ret;
3107}
3108
3109static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb)
3110{
3111	if (!mstb->port_parent)
3112		return NULL;
3113
3114	if (mstb->port_parent->mstb != mstb)
3115		return mstb->port_parent;
3116
3117	return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
3118}
3119
3120/*
3121 * Searches upwards in the topology starting from mstb to try to find the
3122 * closest available parent of mstb that's still connected to the rest of the
3123 * topology. This can be used in order to perform operations like releasing
3124 * payloads, where the branch device which owned the payload may no longer be
3125 * around and thus would require that the payload on the last living relative
3126 * be freed instead.
3127 */
3128static struct drm_dp_mst_branch *
3129drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
3130					struct drm_dp_mst_branch *mstb,
3131					int *port_num)
3132{
3133	struct drm_dp_mst_branch *rmstb = NULL;
3134	struct drm_dp_mst_port *found_port;
3135
3136	mutex_lock(&mgr->lock);
3137	if (!mgr->mst_primary)
3138		goto out;
3139
3140	do {
3141		found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
3142		if (!found_port)
3143			break;
3144
3145		if (drm_dp_mst_topology_try_get_mstb(found_port->parent)) {
3146			rmstb = found_port->parent;
3147			*port_num = found_port->port_num;
3148		} else {
3149			/* Search again, starting from this parent */
3150			mstb = found_port->parent;
3151		}
3152	} while (!rmstb);
3153out:
3154	mutex_unlock(&mgr->lock);
3155	return rmstb;
3156}
3157
3158static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
3159				   struct drm_dp_mst_port *port,
3160				   int id,
3161				   int pbn)
3162{
3163	struct drm_dp_sideband_msg_tx *txmsg;
3164	struct drm_dp_mst_branch *mstb;
3165	int ret, port_num;
3166	u8 sinks[DRM_DP_MAX_SDP_STREAMS];
3167	int i;
3168
3169	port_num = port->port_num;
3170	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3171	if (!mstb) {
3172		mstb = drm_dp_get_last_connected_port_and_mstb(mgr,
3173							       port->parent,
3174							       &port_num);
3175
3176		if (!mstb)
3177			return -EINVAL;
3178	}
3179
3180	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3181	if (!txmsg) {
3182		ret = -ENOMEM;
3183		goto fail_put;
3184	}
3185
3186	for (i = 0; i < port->num_sdp_streams; i++)
3187		sinks[i] = i;
3188
3189	txmsg->dst = mstb;
3190	build_allocate_payload(txmsg, port_num,
3191			       id,
3192			       pbn, port->num_sdp_streams, sinks);
3193
3194	drm_dp_queue_down_tx(mgr, txmsg);
3195
3196	/*
3197	 * FIXME: there is a small chance that between getting the last
3198	 * connected mstb and sending the payload message, the last connected
3199	 * mstb could also be removed from the topology. In the future, this
3200	 * needs to be fixed by restarting the
3201	 * drm_dp_get_last_connected_port_and_mstb() search in the event of a
3202	 * timeout if the topology is still connected to the system.
3203	 */
3204	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3205	if (ret > 0) {
3206		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3207			ret = -EINVAL;
3208		else
3209			ret = 0;
3210	}
3211	kfree(txmsg);
3212fail_put:
3213	drm_dp_mst_topology_put_mstb(mstb);
3214	return ret;
3215}
3216
3217int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
3218				 struct drm_dp_mst_port *port, bool power_up)
3219{
3220	struct drm_dp_sideband_msg_tx *txmsg;
3221	int ret;
3222
3223	port = drm_dp_mst_topology_get_port_validated(mgr, port);
3224	if (!port)
3225		return -EINVAL;
3226
3227	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3228	if (!txmsg) {
3229		drm_dp_mst_topology_put_port(port);
3230		return -ENOMEM;
3231	}
3232
3233	txmsg->dst = port->parent;
3234	build_power_updown_phy(txmsg, port->port_num, power_up);
3235	drm_dp_queue_down_tx(mgr, txmsg);
3236
3237	ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg);
3238	if (ret > 0) {
3239		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3240			ret = -EINVAL;
3241		else
3242			ret = 0;
3243	}
3244	kfree(txmsg);
3245	drm_dp_mst_topology_put_port(port);
3246
3247	return ret;
3248}
3249EXPORT_SYMBOL(drm_dp_send_power_updown_phy);
3250
3251int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
3252		struct drm_dp_mst_port *port,
3253		struct drm_dp_query_stream_enc_status_ack_reply *status)
3254{
3255	struct drm_dp_sideband_msg_tx *txmsg;
3256	u8 nonce[7];
3257	int ret;
3258
3259	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3260	if (!txmsg)
3261		return -ENOMEM;
3262
3263	port = drm_dp_mst_topology_get_port_validated(mgr, port);
3264	if (!port) {
3265		ret = -EINVAL;
3266		goto out_get_port;
3267	}
3268
3269	get_random_bytes(nonce, sizeof(nonce));
3270
3271	/*
3272	 * "Source device targets the QUERY_STREAM_ENCRYPTION_STATUS message
3273	 *  transaction at the MST Branch device directly connected to the
3274	 *  Source"
3275	 */
3276	txmsg->dst = mgr->mst_primary;
3277
3278	build_query_stream_enc_status(txmsg, port->vcpi.vcpi, nonce);
3279
3280	drm_dp_queue_down_tx(mgr, txmsg);
3281
3282	ret = drm_dp_mst_wait_tx_reply(mgr->mst_primary, txmsg);
3283	if (ret < 0) {
3284		goto out;
3285	} else if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
3286		drm_dbg_kms(mgr->dev, "query encryption status nak received\n");
3287		ret = -ENXIO;
3288		goto out;
3289	}
3290
3291	ret = 0;
3292	memcpy(status, &txmsg->reply.u.enc_status, sizeof(*status));
3293
3294out:
3295	drm_dp_mst_topology_put_port(port);
3296out_get_port:
3297	kfree(txmsg);
3298	return ret;
3299}
3300EXPORT_SYMBOL(drm_dp_send_query_stream_enc_status);
3301
3302static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3303				       int id,
3304				       struct drm_dp_payload *payload)
3305{
3306	int ret;
3307
3308	ret = drm_dp_dpcd_write_payload(mgr, id, payload);
3309	if (ret < 0) {
3310		payload->payload_state = 0;
3311		return ret;
3312	}
3313	payload->payload_state = DP_PAYLOAD_LOCAL;
3314	return 0;
3315}
3316
3317static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
3318				       struct drm_dp_mst_port *port,
3319				       int id,
3320				       struct drm_dp_payload *payload)
3321{
3322	int ret;
3323
3324	ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
3325	if (ret < 0)
3326		return ret;
3327	payload->payload_state = DP_PAYLOAD_REMOTE;
3328	return ret;
3329}
3330
3331static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
3332					struct drm_dp_mst_port *port,
3333					int id,
3334					struct drm_dp_payload *payload)
3335{
3336	drm_dbg_kms(mgr->dev, "\n");
3337	/* it's okay for these to fail */
3338	if (port) {
3339		drm_dp_payload_send_msg(mgr, port, id, 0);
3340	}
3341
3342	drm_dp_dpcd_write_payload(mgr, id, payload);
3343	payload->payload_state = DP_PAYLOAD_DELETE_LOCAL;
3344	return 0;
3345}
3346
3347static int drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
3348					int id,
3349					struct drm_dp_payload *payload)
3350{
3351	payload->payload_state = 0;
3352	return 0;
3353}
3354
3355/**
3356 * drm_dp_update_payload_part1() - Execute payload update part 1
3357 * @mgr: manager to use.
3358 *
3359 * This iterates over all proposed virtual channels, and tries to
3360 * allocate space in the link for them. For 0->slots transitions,
3361 * this step just writes the VCPI to the MST device. For slots->0
3362 * transitions, this writes the updated VCPIs and removes the
3363 * remote VC payloads.
3364 *
3365 * after calling this the driver should generate ACT and payload
3366 * packets.
3367 */
3368int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
3369{
3370	struct drm_dp_payload req_payload;
3371	struct drm_dp_mst_port *port;
3372	int i, j;
3373	int cur_slots = 1;
3374	bool skip;
3375
3376	mutex_lock(&mgr->payload_lock);
3377	for (i = 0; i < mgr->max_payloads; i++) {
3378		struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
3379		struct drm_dp_payload *payload = &mgr->payloads[i];
3380		bool put_port = false;
3381
3382		/* solve the current payloads - compare to the hw ones
3383		   - update the hw view */
3384		req_payload.start_slot = cur_slots;
3385		if (vcpi) {
3386			port = container_of(vcpi, struct drm_dp_mst_port,
3387					    vcpi);
3388
3389			mutex_lock(&mgr->lock);
3390			skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
3391			mutex_unlock(&mgr->lock);
3392
3393			if (skip) {
3394				drm_dbg_kms(mgr->dev,
3395					    "Virtual channel %d is not in current topology\n",
3396					    i);
3397				continue;
3398			}
3399			/* Validated ports don't matter if we're releasing
3400			 * VCPI
3401			 */
3402			if (vcpi->num_slots) {
3403				port = drm_dp_mst_topology_get_port_validated(
3404				    mgr, port);
3405				if (!port) {
3406					if (vcpi->num_slots == payload->num_slots) {
3407						cur_slots += vcpi->num_slots;
3408						payload->start_slot = req_payload.start_slot;
3409						continue;
3410					} else {
3411						drm_dbg_kms(mgr->dev,
3412							    "Fail:set payload to invalid sink");
3413						mutex_unlock(&mgr->payload_lock);
3414						return -EINVAL;
3415					}
3416				}
3417				put_port = true;
3418			}
3419
3420			req_payload.num_slots = vcpi->num_slots;
3421			req_payload.vcpi = vcpi->vcpi;
3422		} else {
3423			port = NULL;
3424			req_payload.num_slots = 0;
3425		}
3426
3427		payload->start_slot = req_payload.start_slot;
3428		/* work out what is required to happen with this payload */
3429		if (payload->num_slots != req_payload.num_slots) {
3430
3431			/* need to push an update for this payload */
3432			if (req_payload.num_slots) {
3433				drm_dp_create_payload_step1(mgr, vcpi->vcpi,
3434							    &req_payload);
3435				payload->num_slots = req_payload.num_slots;
3436				payload->vcpi = req_payload.vcpi;
3437
3438			} else if (payload->num_slots) {
3439				payload->num_slots = 0;
3440				drm_dp_destroy_payload_step1(mgr, port,
3441							     payload->vcpi,
3442							     payload);
3443				req_payload.payload_state =
3444					payload->payload_state;
3445				payload->start_slot = 0;
3446			}
3447			payload->payload_state = req_payload.payload_state;
3448		}
3449		cur_slots += req_payload.num_slots;
3450
3451		if (put_port)
3452			drm_dp_mst_topology_put_port(port);
3453	}
3454
3455	for (i = 0; i < mgr->max_payloads; /* do nothing */) {
3456		if (mgr->payloads[i].payload_state != DP_PAYLOAD_DELETE_LOCAL) {
3457			i++;
3458			continue;
3459		}
3460
3461		drm_dbg_kms(mgr->dev, "removing payload %d\n", i);
3462		for (j = i; j < mgr->max_payloads - 1; j++) {
3463			mgr->payloads[j] = mgr->payloads[j + 1];
3464			mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
3465
3466			if (mgr->proposed_vcpis[j] &&
3467			    mgr->proposed_vcpis[j]->num_slots) {
3468				set_bit(j + 1, &mgr->payload_mask);
3469			} else {
3470				clear_bit(j + 1, &mgr->payload_mask);
3471			}
3472		}
3473
3474		memset(&mgr->payloads[mgr->max_payloads - 1], 0,
3475		       sizeof(struct drm_dp_payload));
3476		mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
3477		clear_bit(mgr->max_payloads, &mgr->payload_mask);
3478	}
3479	mutex_unlock(&mgr->payload_lock);
3480
3481	return 0;
3482}
3483EXPORT_SYMBOL(drm_dp_update_payload_part1);
3484
3485/**
3486 * drm_dp_update_payload_part2() - Execute payload update part 2
3487 * @mgr: manager to use.
3488 *
3489 * This iterates over all proposed virtual channels, and tries to
3490 * allocate space in the link for them. For 0->slots transitions,
3491 * this step writes the remote VC payload commands. For slots->0
3492 * this just resets some internal state.
3493 */
3494int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
3495{
3496	struct drm_dp_mst_port *port;
3497	int i;
3498	int ret = 0;
3499	bool skip;
3500
3501	mutex_lock(&mgr->payload_lock);
3502	for (i = 0; i < mgr->max_payloads; i++) {
3503
3504		if (!mgr->proposed_vcpis[i])
3505			continue;
3506
3507		port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
3508
3509		mutex_lock(&mgr->lock);
3510		skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
3511		mutex_unlock(&mgr->lock);
3512
3513		if (skip)
3514			continue;
3515
3516		drm_dbg_kms(mgr->dev, "payload %d %d\n", i, mgr->payloads[i].payload_state);
3517		if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
3518			ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
3519		} else if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
3520			ret = drm_dp_destroy_payload_step2(mgr, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
3521		}
3522		if (ret) {
3523			mutex_unlock(&mgr->payload_lock);
3524			return ret;
3525		}
3526	}
3527	mutex_unlock(&mgr->payload_lock);
3528	return 0;
3529}
3530EXPORT_SYMBOL(drm_dp_update_payload_part2);
3531
3532static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
3533				 struct drm_dp_mst_port *port,
3534				 int offset, int size, u8 *bytes)
3535{
3536	int ret = 0;
3537	struct drm_dp_sideband_msg_tx *txmsg;
3538	struct drm_dp_mst_branch *mstb;
3539
3540	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3541	if (!mstb)
3542		return -EINVAL;
3543
3544	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3545	if (!txmsg) {
3546		ret = -ENOMEM;
3547		goto fail_put;
3548	}
3549
3550	build_dpcd_read(txmsg, port->port_num, offset, size);
3551	txmsg->dst = port->parent;
3552
3553	drm_dp_queue_down_tx(mgr, txmsg);
3554
3555	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3556	if (ret < 0)
3557		goto fail_free;
3558
3559	/* DPCD read should never be NACKed */
3560	if (txmsg->reply.reply_type == 1) {
3561		drm_err(mgr->dev, "mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n",
3562			mstb, port->port_num, offset, size);
3563		ret = -EIO;
3564		goto fail_free;
3565	}
3566
3567	if (txmsg->reply.u.remote_dpcd_read_ack.num_bytes != size) {
3568		ret = -EPROTO;
3569		goto fail_free;
3570	}
3571
3572	ret = min_t(size_t, txmsg->reply.u.remote_dpcd_read_ack.num_bytes,
3573		    size);
3574	memcpy(bytes, txmsg->reply.u.remote_dpcd_read_ack.bytes, ret);
3575
3576fail_free:
3577	kfree(txmsg);
3578fail_put:
3579	drm_dp_mst_topology_put_mstb(mstb);
3580
3581	return ret;
3582}
3583
3584static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
3585				  struct drm_dp_mst_port *port,
3586				  int offset, int size, u8 *bytes)
3587{
3588	int ret;
3589	struct drm_dp_sideband_msg_tx *txmsg;
3590	struct drm_dp_mst_branch *mstb;
3591
3592	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
3593	if (!mstb)
3594		return -EINVAL;
3595
3596	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3597	if (!txmsg) {
3598		ret = -ENOMEM;
3599		goto fail_put;
3600	}
3601
3602	build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
3603	txmsg->dst = mstb;
3604
3605	drm_dp_queue_down_tx(mgr, txmsg);
3606
3607	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3608	if (ret > 0) {
3609		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
3610			ret = -EIO;
3611		else
3612			ret = size;
3613	}
3614
3615	kfree(txmsg);
3616fail_put:
3617	drm_dp_mst_topology_put_mstb(mstb);
3618	return ret;
3619}
3620
3621static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
3622{
3623	struct drm_dp_sideband_msg_reply_body reply;
3624
3625	reply.reply_type = DP_SIDEBAND_REPLY_ACK;
3626	reply.req_type = req_type;
3627	drm_dp_encode_sideband_reply(&reply, msg);
3628	return 0;
3629}
3630
3631static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
3632				    struct drm_dp_mst_branch *mstb,
3633				    int req_type, bool broadcast)
3634{
3635	struct drm_dp_sideband_msg_tx *txmsg;
3636
3637	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3638	if (!txmsg)
3639		return -ENOMEM;
3640
3641	txmsg->dst = mstb;
3642	drm_dp_encode_up_ack_reply(txmsg, req_type);
3643
3644	mutex_lock(&mgr->qlock);
3645	/* construct a chunk from the first msg in the tx_msg queue */
3646	process_single_tx_qlock(mgr, txmsg, true);
3647	mutex_unlock(&mgr->qlock);
3648
3649	kfree(txmsg);
3650	return 0;
3651}
3652
3653/**
3654 * drm_dp_get_vc_payload_bw - get the VC payload BW for an MST link
3655 * @mgr: The &drm_dp_mst_topology_mgr to use
3656 * @link_rate: link rate in 10kbits/s units
3657 * @link_lane_count: lane count
3658 *
3659 * Calculate the total bandwidth of a MultiStream Transport link. The returned
3660 * value is in units of PBNs/(timeslots/1 MTP). This value can be used to
3661 * convert the number of PBNs required for a given stream to the number of
3662 * timeslots this stream requires in each MTP.
3663 */
3664int drm_dp_get_vc_payload_bw(const struct drm_dp_mst_topology_mgr *mgr,
3665			     int link_rate, int link_lane_count)
3666{
3667	if (link_rate == 0 || link_lane_count == 0)
3668		drm_dbg_kms(mgr->dev, "invalid link rate/lane count: (%d / %d)\n",
3669			    link_rate, link_lane_count);
3670
3671	/* See DP v2.0 2.6.4.2, VCPayload_Bandwidth_for_OneTimeSlotPer_MTP_Allocation */
3672	return link_rate * link_lane_count / 54000;
3673}
3674EXPORT_SYMBOL(drm_dp_get_vc_payload_bw);
3675
3676/**
3677 * drm_dp_read_mst_cap() - check whether or not a sink supports MST
3678 * @aux: The DP AUX channel to use
3679 * @dpcd: A cached copy of the DPCD capabilities for this sink
3680 *
3681 * Returns: %True if the sink supports MST, %false otherwise
3682 */
3683bool drm_dp_read_mst_cap(struct drm_dp_aux *aux,
3684			 const u8 dpcd[DP_RECEIVER_CAP_SIZE])
3685{
3686	u8 mstm_cap;
3687
3688	if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12)
3689		return false;
3690
3691	if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, &mstm_cap) != 1)
3692		return false;
3693
3694	return mstm_cap & DP_MST_CAP;
3695}
3696EXPORT_SYMBOL(drm_dp_read_mst_cap);
3697
3698/**
3699 * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
3700 * @mgr: manager to set state for
3701 * @mst_state: true to enable MST on this connector - false to disable.
3702 *
3703 * This is called by the driver when it detects an MST capable device plugged
3704 * into a DP MST capable port, or when a DP MST capable device is unplugged.
3705 */
3706int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
3707{
3708	int ret = 0;
3709	struct drm_dp_mst_branch *mstb = NULL;
3710
3711	mutex_lock(&mgr->payload_lock);
3712	mutex_lock(&mgr->lock);
3713	if (mst_state == mgr->mst_state)
3714		goto out_unlock;
3715
3716	mgr->mst_state = mst_state;
3717	/* set the device into MST mode */
3718	if (mst_state) {
3719		struct drm_dp_payload reset_pay;
3720		int lane_count;
3721		int link_rate;
3722
3723		WARN_ON(mgr->mst_primary);
3724
3725		/* get dpcd info */
3726		ret = drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd);
3727		if (ret < 0) {
3728			drm_dbg_kms(mgr->dev, "%s: failed to read DPCD, ret %d\n",
3729				    mgr->aux->name, ret);
3730			goto out_unlock;
3731		}
3732
3733		lane_count = min_t(int, mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK, mgr->max_lane_count);
3734		link_rate = min_t(int, drm_dp_bw_code_to_link_rate(mgr->dpcd[1]), mgr->max_link_rate);
3735		mgr->pbn_div = drm_dp_get_vc_payload_bw(mgr,
3736							link_rate,
3737							lane_count);
3738		if (mgr->pbn_div == 0) {
3739			ret = -EINVAL;
3740			goto out_unlock;
3741		}
3742
3743		/* add initial branch device at LCT 1 */
3744		mstb = drm_dp_add_mst_branch_device(1, NULL);
3745		if (mstb == NULL) {
3746			ret = -ENOMEM;
3747			goto out_unlock;
3748		}
3749		mstb->mgr = mgr;
3750
3751		/* give this the main reference */
3752		mgr->mst_primary = mstb;
3753		drm_dp_mst_topology_get_mstb(mgr->mst_primary);
3754
3755		ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3756					 DP_MST_EN |
3757					 DP_UP_REQ_EN |
3758					 DP_UPSTREAM_IS_SRC);
3759		if (ret < 0)
3760			goto out_unlock;
3761
3762		reset_pay.start_slot = 0;
3763		reset_pay.num_slots = 0x3f;
3764		drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
3765
3766		queue_work(system_long_wq, &mgr->work);
3767
3768		ret = 0;
3769	} else {
3770		/* disable MST on the device */
3771		mstb = mgr->mst_primary;
3772		mgr->mst_primary = NULL;
3773		/* this can fail if the device is gone */
3774		drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
3775		ret = 0;
3776		memset(mgr->payloads, 0,
3777		       mgr->max_payloads * sizeof(mgr->payloads[0]));
3778		memset(mgr->proposed_vcpis, 0,
3779		       mgr->max_payloads * sizeof(mgr->proposed_vcpis[0]));
3780		mgr->payload_mask = 0;
3781		set_bit(0, &mgr->payload_mask);
3782		mgr->vcpi_mask = 0;
3783		mgr->payload_id_table_cleared = false;
3784	}
3785
3786out_unlock:
3787	mutex_unlock(&mgr->lock);
3788	mutex_unlock(&mgr->payload_lock);
3789	if (mstb)
3790		drm_dp_mst_topology_put_mstb(mstb);
3791	return ret;
3792
3793}
3794EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
3795
3796static void
3797drm_dp_mst_topology_mgr_invalidate_mstb(struct drm_dp_mst_branch *mstb)
3798{
3799	struct drm_dp_mst_port *port;
3800
3801	/* The link address will need to be re-sent on resume */
3802	mstb->link_address_sent = false;
3803
3804	list_for_each_entry(port, &mstb->ports, next)
3805		if (port->mstb)
3806			drm_dp_mst_topology_mgr_invalidate_mstb(port->mstb);
3807}
3808
3809/**
3810 * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
3811 * @mgr: manager to suspend
3812 *
3813 * This function tells the MST device that we can't handle UP messages
3814 * anymore. This should stop it from sending any since we are suspended.
3815 */
3816void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
3817{
3818	mutex_lock(&mgr->lock);
3819	drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3820			   DP_MST_EN | DP_UPSTREAM_IS_SRC);
3821	mutex_unlock(&mgr->lock);
3822	flush_work(&mgr->up_req_work);
3823	flush_work(&mgr->work);
3824	flush_work(&mgr->delayed_destroy_work);
3825
3826	mutex_lock(&mgr->lock);
3827	if (mgr->mst_state && mgr->mst_primary)
3828		drm_dp_mst_topology_mgr_invalidate_mstb(mgr->mst_primary);
3829	mutex_unlock(&mgr->lock);
3830}
3831EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
3832
3833/**
3834 * drm_dp_mst_topology_mgr_resume() - resume the MST manager
3835 * @mgr: manager to resume
3836 * @sync: whether or not to perform topology reprobing synchronously
3837 *
3838 * This will fetch DPCD and see if the device is still there,
3839 * if it is, it will rewrite the MSTM control bits, and return.
3840 *
3841 * If the device fails this returns -1, and the driver should do
3842 * a full MST reprobe, in case we were undocked.
3843 *
3844 * During system resume (where it is assumed that the driver will be calling
3845 * drm_atomic_helper_resume()) this function should be called beforehand with
3846 * @sync set to true. In contexts like runtime resume where the driver is not
3847 * expected to be calling drm_atomic_helper_resume(), this function should be
3848 * called with @sync set to false in order to avoid deadlocking.
3849 *
3850 * Returns: -1 if the MST topology was removed while we were suspended, 0
3851 * otherwise.
3852 */
3853int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr,
3854				   bool sync)
3855{
3856	int ret;
3857	u8 guid[16];
3858
3859	mutex_lock(&mgr->lock);
3860	if (!mgr->mst_primary)
3861		goto out_fail;
3862
3863	ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd,
3864			       DP_RECEIVER_CAP_SIZE);
3865	if (ret != DP_RECEIVER_CAP_SIZE) {
3866		drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3867		goto out_fail;
3868	}
3869
3870	ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
3871				 DP_MST_EN |
3872				 DP_UP_REQ_EN |
3873				 DP_UPSTREAM_IS_SRC);
3874	if (ret < 0) {
3875		drm_dbg_kms(mgr->dev, "mst write failed - undocked during suspend?\n");
3876		goto out_fail;
3877	}
3878
3879	/* Some hubs forget their guids after they resume */
3880	ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
3881	if (ret != 16) {
3882		drm_dbg_kms(mgr->dev, "dpcd read failed - undocked during suspend?\n");
3883		goto out_fail;
3884	}
3885
3886	ret = drm_dp_check_mstb_guid(mgr->mst_primary, guid);
3887	if (ret) {
3888		drm_dbg_kms(mgr->dev, "check mstb failed - undocked during suspend?\n");
3889		goto out_fail;
3890	}
3891
3892	/*
3893	 * For the final step of resuming the topology, we need to bring the
3894	 * state of our in-memory topology back into sync with reality. So,
3895	 * restart the probing process as if we're probing a new hub
3896	 */
3897	queue_work(system_long_wq, &mgr->work);
3898	mutex_unlock(&mgr->lock);
3899
3900	if (sync) {
3901		drm_dbg_kms(mgr->dev,
3902			    "Waiting for link probe work to finish re-syncing topology...\n");
3903		flush_work(&mgr->work);
3904	}
3905
3906	return 0;
3907
3908out_fail:
3909	mutex_unlock(&mgr->lock);
3910	return -1;
3911}
3912EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
3913
3914static bool
3915drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up,
3916		      struct drm_dp_mst_branch **mstb)
3917{
3918	int len;
3919	u8 replyblock[32];
3920	int replylen, curreply;
3921	int ret;
3922	u8 hdrlen;
3923	struct drm_dp_sideband_msg_hdr hdr;
3924	struct drm_dp_sideband_msg_rx *msg =
3925		up ? &mgr->up_req_recv : &mgr->down_rep_recv;
3926	int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE :
3927			   DP_SIDEBAND_MSG_DOWN_REP_BASE;
3928
3929	if (!up)
3930		*mstb = NULL;
3931
3932	len = min(mgr->max_dpcd_transaction_bytes, 16);
3933	ret = drm_dp_dpcd_read(mgr->aux, basereg, replyblock, len);
3934	if (ret != len) {
3935		drm_dbg_kms(mgr->dev, "failed to read DPCD down rep %d %d\n", len, ret);
3936		return false;
3937	}
3938
3939	ret = drm_dp_decode_sideband_msg_hdr(mgr, &hdr, replyblock, len, &hdrlen);
3940	if (ret == false) {
3941		print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16,
3942			       1, replyblock, len, false);
3943		drm_dbg_kms(mgr->dev, "ERROR: failed header\n");
3944		return false;
3945	}
3946
3947	if (!up) {
3948		/* Caller is responsible for giving back this reference */
3949		*mstb = drm_dp_get_mst_branch_device(mgr, hdr.lct, hdr.rad);
3950		if (!*mstb) {
3951			drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr.lct);
3952			return false;
3953		}
3954	}
3955
3956	if (!drm_dp_sideband_msg_set_header(msg, &hdr, hdrlen)) {
3957		drm_dbg_kms(mgr->dev, "sideband msg set header failed %d\n", replyblock[0]);
3958		return false;
3959	}
3960
3961	replylen = min(msg->curchunk_len, (u8)(len - hdrlen));
3962	ret = drm_dp_sideband_append_payload(msg, replyblock + hdrlen, replylen);
3963	if (!ret) {
3964		drm_dbg_kms(mgr->dev, "sideband msg build failed %d\n", replyblock[0]);
3965		return false;
3966	}
3967
3968	replylen = msg->curchunk_len + msg->curchunk_hdrlen - len;
3969	curreply = len;
3970	while (replylen > 0) {
3971		len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
3972		ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
3973				    replyblock, len);
3974		if (ret != len) {
3975			drm_dbg_kms(mgr->dev, "failed to read a chunk (len %d, ret %d)\n",
3976				    len, ret);
3977			return false;
3978		}
3979
3980		ret = drm_dp_sideband_append_payload(msg, replyblock, len);
3981		if (!ret) {
3982			drm_dbg_kms(mgr->dev, "failed to build sideband msg\n");
3983			return false;
3984		}
3985
3986		curreply += len;
3987		replylen -= len;
3988	}
3989	return true;
3990}
3991
3992static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
3993{
3994	struct drm_dp_sideband_msg_tx *txmsg;
3995	struct drm_dp_mst_branch *mstb = NULL;
3996	struct drm_dp_sideband_msg_rx *msg = &mgr->down_rep_recv;
3997
3998	if (!drm_dp_get_one_sb_msg(mgr, false, &mstb))
3999		goto out;
4000
4001	/* Multi-packet message transmission, don't clear the reply */
4002	if (!msg->have_eomt)
4003		goto out;
4004
4005	/* find the message */
4006	mutex_lock(&mgr->qlock);
4007	txmsg = list_first_entry_or_null(&mgr->tx_msg_downq,
4008					 struct drm_dp_sideband_msg_tx, next);
4009	mutex_unlock(&mgr->qlock);
4010
4011	/* Were we actually expecting a response, and from this mstb? */
4012	if (!txmsg || txmsg->dst != mstb) {
4013		struct drm_dp_sideband_msg_hdr *hdr;
4014
4015		hdr = &msg->initial_hdr;
4016		drm_dbg_kms(mgr->dev, "Got MST reply with no msg %p %d %d %02x %02x\n",
4017			    mstb, hdr->seqno, hdr->lct, hdr->rad[0], msg->msg[0]);
4018		goto out_clear_reply;
4019	}
4020
4021	drm_dp_sideband_parse_reply(mgr, msg, &txmsg->reply);
4022
4023	if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
4024		drm_dbg_kms(mgr->dev,
4025			    "Got NAK reply: req 0x%02x (%s), reason 0x%02x (%s), nak data 0x%02x\n",
4026			    txmsg->reply.req_type,
4027			    drm_dp_mst_req_type_str(txmsg->reply.req_type),
4028			    txmsg->reply.u.nak.reason,
4029			    drm_dp_mst_nak_reason_str(txmsg->reply.u.nak.reason),
4030			    txmsg->reply.u.nak.nak_data);
4031	}
4032
4033	memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
4034	drm_dp_mst_topology_put_mstb(mstb);
4035
4036	mutex_lock(&mgr->qlock);
4037	txmsg->state = DRM_DP_SIDEBAND_TX_RX;
4038	list_del(&txmsg->next);
4039	mutex_unlock(&mgr->qlock);
4040
4041	wake_up_all(&mgr->tx_waitq);
4042
4043	return 0;
4044
4045out_clear_reply:
4046	memset(msg, 0, sizeof(struct drm_dp_sideband_msg_rx));
4047out:
4048	if (mstb)
4049		drm_dp_mst_topology_put_mstb(mstb);
4050
4051	return 0;
4052}
4053
4054static inline bool
4055drm_dp_mst_process_up_req(struct drm_dp_mst_topology_mgr *mgr,
4056			  struct drm_dp_pending_up_req *up_req)
4057{
4058	struct drm_dp_mst_branch *mstb = NULL;
4059	struct drm_dp_sideband_msg_req_body *msg = &up_req->msg;
4060	struct drm_dp_sideband_msg_hdr *hdr = &up_req->hdr;
4061	bool hotplug = false;
4062
4063	if (hdr->broadcast) {
4064		const u8 *guid = NULL;
4065
4066		if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY)
4067			guid = msg->u.conn_stat.guid;
4068		else if (msg->req_type == DP_RESOURCE_STATUS_NOTIFY)
4069			guid = msg->u.resource_stat.guid;
4070
4071		if (guid)
4072			mstb = drm_dp_get_mst_branch_device_by_guid(mgr, guid);
4073	} else {
4074		mstb = drm_dp_get_mst_branch_device(mgr, hdr->lct, hdr->rad);
4075	}
4076
4077	if (!mstb) {
4078		drm_dbg_kms(mgr->dev, "Got MST reply from unknown device %d\n", hdr->lct);
4079		return false;
4080	}
4081
4082	/* TODO: Add missing handler for DP_RESOURCE_STATUS_NOTIFY events */
4083	if (msg->req_type == DP_CONNECTION_STATUS_NOTIFY) {
4084		drm_dp_mst_handle_conn_stat(mstb, &msg->u.conn_stat);
4085		hotplug = true;
4086	}
4087
4088	drm_dp_mst_topology_put_mstb(mstb);
4089	return hotplug;
4090}
4091
4092static void drm_dp_mst_up_req_work(struct work_struct *work)
4093{
4094	struct drm_dp_mst_topology_mgr *mgr =
4095		container_of(work, struct drm_dp_mst_topology_mgr,
4096			     up_req_work);
4097	struct drm_dp_pending_up_req *up_req;
4098	bool send_hotplug = false;
4099
4100	mutex_lock(&mgr->probe_lock);
4101	while (true) {
4102		mutex_lock(&mgr->up_req_lock);
4103		up_req = list_first_entry_or_null(&mgr->up_req_list,
4104						  struct drm_dp_pending_up_req,
4105						  next);
4106		if (up_req)
4107			list_del(&up_req->next);
4108		mutex_unlock(&mgr->up_req_lock);
4109
4110		if (!up_req)
4111			break;
4112
4113		send_hotplug |= drm_dp_mst_process_up_req(mgr, up_req);
4114		kfree(up_req);
4115	}
4116	mutex_unlock(&mgr->probe_lock);
4117
4118	if (send_hotplug)
4119		drm_kms_helper_hotplug_event(mgr->dev);
4120}
4121
4122static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
4123{
4124	struct drm_dp_pending_up_req *up_req;
4125
4126	if (!drm_dp_get_one_sb_msg(mgr, true, NULL))
4127		goto out;
4128
4129	if (!mgr->up_req_recv.have_eomt)
4130		return 0;
4131
4132	up_req = kzalloc(sizeof(*up_req), GFP_KERNEL);
4133	if (!up_req)
4134		return -ENOMEM;
4135
4136	INIT_LIST_HEAD(&up_req->next);
4137
4138	drm_dp_sideband_parse_req(mgr, &mgr->up_req_recv, &up_req->msg);
4139
4140	if (up_req->msg.req_type != DP_CONNECTION_STATUS_NOTIFY &&
4141	    up_req->msg.req_type != DP_RESOURCE_STATUS_NOTIFY) {
4142		drm_dbg_kms(mgr->dev, "Received unknown up req type, ignoring: %x\n",
4143			    up_req->msg.req_type);
4144		kfree(up_req);
4145		goto out;
4146	}
4147
4148	drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, up_req->msg.req_type,
4149				 false);
4150
4151	if (up_req->msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
4152		const struct drm_dp_connection_status_notify *conn_stat =
4153			&up_req->msg.u.conn_stat;
4154
4155		drm_dbg_kms(mgr->dev, "Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n",
4156			    conn_stat->port_number,
4157			    conn_stat->legacy_device_plug_status,
4158			    conn_stat->displayport_device_plug_status,
4159			    conn_stat->message_capability_status,
4160			    conn_stat->input_port,
4161			    conn_stat->peer_device_type);
4162	} else if (up_req->msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
4163		const struct drm_dp_resource_status_notify *res_stat =
4164			&up_req->msg.u.resource_stat;
4165
4166		drm_dbg_kms(mgr->dev, "Got RSN: pn: %d avail_pbn %d\n",
4167			    res_stat->port_number,
4168			    res_stat->available_pbn);
4169	}
4170
4171	up_req->hdr = mgr->up_req_recv.initial_hdr;
4172	mutex_lock(&mgr->up_req_lock);
4173	list_add_tail(&up_req->next, &mgr->up_req_list);
4174	mutex_unlock(&mgr->up_req_lock);
4175	queue_work(system_long_wq, &mgr->up_req_work);
4176
4177out:
4178	memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
4179	return 0;
4180}
4181
4182/**
4183 * drm_dp_mst_hpd_irq() - MST hotplug IRQ notify
4184 * @mgr: manager to notify irq for.
4185 * @esi: 4 bytes from SINK_COUNT_ESI
4186 * @handled: whether the hpd interrupt was consumed or not
4187 *
4188 * This should be called from the driver when it detects a short IRQ,
4189 * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
4190 * topology manager will process the sideband messages received as a result
4191 * of this.
4192 */
4193int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled)
4194{
4195	int ret = 0;
4196	int sc;
4197	*handled = false;
4198	sc = esi[0] & 0x3f;
4199
4200	if (sc != mgr->sink_count) {
4201		mgr->sink_count = sc;
4202		*handled = true;
4203	}
4204
4205	if (esi[1] & DP_DOWN_REP_MSG_RDY) {
4206		ret = drm_dp_mst_handle_down_rep(mgr);
4207		*handled = true;
4208	}
4209
4210	if (esi[1] & DP_UP_REQ_MSG_RDY) {
4211		ret |= drm_dp_mst_handle_up_req(mgr);
4212		*handled = true;
4213	}
4214
4215	drm_dp_mst_kick_tx(mgr);
4216	return ret;
4217}
4218EXPORT_SYMBOL(drm_dp_mst_hpd_irq);
4219
4220/**
4221 * drm_dp_mst_detect_port() - get connection status for an MST port
4222 * @connector: DRM connector for this port
4223 * @ctx: The acquisition context to use for grabbing locks
4224 * @mgr: manager for this port
4225 * @port: pointer to a port
4226 *
4227 * This returns the current connection state for a port.
4228 */
4229int
4230drm_dp_mst_detect_port(struct drm_connector *connector,
4231		       struct drm_modeset_acquire_ctx *ctx,
4232		       struct drm_dp_mst_topology_mgr *mgr,
4233		       struct drm_dp_mst_port *port)
4234{
4235	int ret;
4236
4237	/* we need to search for the port in the mgr in case it's gone */
4238	port = drm_dp_mst_topology_get_port_validated(mgr, port);
4239	if (!port)
4240		return connector_status_disconnected;
4241
4242	ret = drm_modeset_lock(&mgr->base.lock, ctx);
4243	if (ret)
4244		goto out;
4245
4246	ret = connector_status_disconnected;
4247
4248	if (!port->ddps)
4249		goto out;
4250
4251	switch (port->pdt) {
4252	case DP_PEER_DEVICE_NONE:
4253		break;
4254	case DP_PEER_DEVICE_MST_BRANCHING:
4255		if (!port->mcs)
4256			ret = connector_status_connected;
4257		break;
4258
4259	case DP_PEER_DEVICE_SST_SINK:
4260		ret = connector_status_connected;
4261		/* for logical ports - cache the EDID */
4262		if (port->port_num >= DP_MST_LOGICAL_PORT_0 && !port->cached_edid)
4263			port->cached_edid = drm_get_edid(connector, &port->aux.ddc);
4264		break;
4265	case DP_PEER_DEVICE_DP_LEGACY_CONV:
4266		if (port->ldps)
4267			ret = connector_status_connected;
4268		break;
4269	}
4270out:
4271	drm_dp_mst_topology_put_port(port);
4272	return ret;
4273}
4274EXPORT_SYMBOL(drm_dp_mst_detect_port);
4275
4276/**
4277 * drm_dp_mst_get_edid() - get EDID for an MST port
4278 * @connector: toplevel connector to get EDID for
4279 * @mgr: manager for this port
4280 * @port: unverified pointer to a port.
4281 *
4282 * This returns an EDID for the port connected to a connector,
4283 * It validates the pointer still exists so the caller doesn't require a
4284 * reference.
4285 */
4286struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4287{
4288	struct edid *edid = NULL;
4289
4290	/* we need to search for the port in the mgr in case it's gone */
4291	port = drm_dp_mst_topology_get_port_validated(mgr, port);
4292	if (!port)
4293		return NULL;
4294
4295	if (port->cached_edid)
4296		edid = drm_edid_duplicate(port->cached_edid);
4297	else {
4298		edid = drm_get_edid(connector, &port->aux.ddc);
4299	}
4300	port->has_audio = drm_detect_monitor_audio(edid);
4301	drm_dp_mst_topology_put_port(port);
4302	return edid;
4303}
4304EXPORT_SYMBOL(drm_dp_mst_get_edid);
4305
4306/**
4307 * drm_dp_find_vcpi_slots() - Find VCPI slots for this PBN value
4308 * @mgr: manager to use
4309 * @pbn: payload bandwidth to convert into slots.
4310 *
4311 * Calculate the number of VCPI slots that will be required for the given PBN
4312 * value. This function is deprecated, and should not be used in atomic
4313 * drivers.
4314 *
4315 * RETURNS:
4316 * The total slots required for this port, or error.
4317 */
4318int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
4319			   int pbn)
4320{
4321	int num_slots;
4322
4323	num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
4324
4325	/* max. time slots - one slot for MTP header */
4326	if (num_slots > 63)
4327		return -ENOSPC;
4328	return num_slots;
4329}
4330EXPORT_SYMBOL(drm_dp_find_vcpi_slots);
4331
4332static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4333			    struct drm_dp_vcpi *vcpi, int pbn, int slots)
4334{
4335	int ret;
4336
4337	/* max. time slots - one slot for MTP header */
4338	if (slots > 63)
4339		return -ENOSPC;
4340
4341	vcpi->pbn = pbn;
4342	vcpi->aligned_pbn = slots * mgr->pbn_div;
4343	vcpi->num_slots = slots;
4344
4345	ret = drm_dp_mst_assign_payload_id(mgr, vcpi);
4346	if (ret < 0)
4347		return ret;
4348	return 0;
4349}
4350
4351/**
4352 * drm_dp_atomic_find_vcpi_slots() - Find and add VCPI slots to the state
4353 * @state: global atomic state
4354 * @mgr: MST topology manager for the port
4355 * @port: port to find vcpi slots for
4356 * @pbn: bandwidth required for the mode in PBN
4357 * @pbn_div: divider for DSC mode that takes FEC into account
4358 *
4359 * Allocates VCPI slots to @port, replacing any previous VCPI allocations it
4360 * may have had. Any atomic drivers which support MST must call this function
4361 * in their &drm_encoder_helper_funcs.atomic_check() callback to change the
4362 * current VCPI allocation for the new state, but only when
4363 * &drm_crtc_state.mode_changed or &drm_crtc_state.connectors_changed is set
4364 * to ensure compatibility with userspace applications that still use the
4365 * legacy modesetting UAPI.
4366 *
4367 * Allocations set by this function are not checked against the bandwidth
4368 * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
4369 *
4370 * Additionally, it is OK to call this function multiple times on the same
4371 * @port as needed. It is not OK however, to call this function and
4372 * drm_dp_atomic_release_vcpi_slots() in the same atomic check phase.
4373 *
4374 * See also:
4375 * drm_dp_atomic_release_vcpi_slots()
4376 * drm_dp_mst_atomic_check()
4377 *
4378 * Returns:
4379 * Total slots in the atomic state assigned for this port, or a negative error
4380 * code if the port no longer exists
4381 */
4382int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
4383				  struct drm_dp_mst_topology_mgr *mgr,
4384				  struct drm_dp_mst_port *port, int pbn,
4385				  int pbn_div)
4386{
4387	struct drm_dp_mst_topology_state *topology_state;
4388	struct drm_dp_vcpi_allocation *pos, *vcpi = NULL;
4389	int prev_slots, prev_bw, req_slots;
4390
4391	topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4392	if (IS_ERR(topology_state))
4393		return PTR_ERR(topology_state);
4394
4395	/* Find the current allocation for this port, if any */
4396	list_for_each_entry(pos, &topology_state->vcpis, next) {
4397		if (pos->port == port) {
4398			vcpi = pos;
4399			prev_slots = vcpi->vcpi;
4400			prev_bw = vcpi->pbn;
4401
4402			/*
4403			 * This should never happen, unless the driver tries
4404			 * releasing and allocating the same VCPI allocation,
4405			 * which is an error
4406			 */
4407			if (WARN_ON(!prev_slots)) {
4408				drm_err(mgr->dev,
4409					"cannot allocate and release VCPI on [MST PORT:%p] in the same state\n",
4410					port);
4411				return -EINVAL;
4412			}
4413
4414			break;
4415		}
4416	}
4417	if (!vcpi) {
4418		prev_slots = 0;
4419		prev_bw = 0;
4420	}
4421
4422	if (pbn_div <= 0)
4423		pbn_div = mgr->pbn_div;
4424
4425	req_slots = DIV_ROUND_UP(pbn, pbn_div);
4426
4427	drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] VCPI %d -> %d\n",
4428		       port->connector->base.id, port->connector->name,
4429		       port, prev_slots, req_slots);
4430	drm_dbg_atomic(mgr->dev, "[CONNECTOR:%d:%s] [MST PORT:%p] PBN %d -> %d\n",
4431		       port->connector->base.id, port->connector->name,
4432		       port, prev_bw, pbn);
4433
4434	/* Add the new allocation to the state */
4435	if (!vcpi) {
4436		vcpi = kzalloc(sizeof(*vcpi), GFP_KERNEL);
4437		if (!vcpi)
4438			return -ENOMEM;
4439
4440		drm_dp_mst_get_port_malloc(port);
4441		vcpi->port = port;
4442		list_add(&vcpi->next, &topology_state->vcpis);
4443	}
4444	vcpi->vcpi = req_slots;
4445	vcpi->pbn = pbn;
4446
4447	return req_slots;
4448}
4449EXPORT_SYMBOL(drm_dp_atomic_find_vcpi_slots);
4450
4451/**
4452 * drm_dp_atomic_release_vcpi_slots() - Release allocated vcpi slots
4453 * @state: global atomic state
4454 * @mgr: MST topology manager for the port
4455 * @port: The port to release the VCPI slots from
4456 *
4457 * Releases any VCPI slots that have been allocated to a port in the atomic
4458 * state. Any atomic drivers which support MST must call this function in
4459 * their &drm_connector_helper_funcs.atomic_check() callback when the
4460 * connector will no longer have VCPI allocated (e.g. because its CRTC was
4461 * removed) when it had VCPI allocated in the previous atomic state.
4462 *
4463 * It is OK to call this even if @port has been removed from the system.
4464 * Additionally, it is OK to call this function multiple times on the same
4465 * @port as needed. It is not OK however, to call this function and
4466 * drm_dp_atomic_find_vcpi_slots() on the same @port in a single atomic check
4467 * phase.
4468 *
4469 * See also:
4470 * drm_dp_atomic_find_vcpi_slots()
4471 * drm_dp_mst_atomic_check()
4472 *
4473 * Returns:
4474 * 0 if all slots for this port were added back to
4475 * &drm_dp_mst_topology_state.avail_slots or negative error code
4476 */
4477int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
4478				     struct drm_dp_mst_topology_mgr *mgr,
4479				     struct drm_dp_mst_port *port)
4480{
4481	struct drm_dp_mst_topology_state *topology_state;
4482	struct drm_dp_vcpi_allocation *pos;
4483	bool found = false;
4484
4485	topology_state = drm_atomic_get_mst_topology_state(state, mgr);
4486	if (IS_ERR(topology_state))
4487		return PTR_ERR(topology_state);
4488
4489	list_for_each_entry(pos, &topology_state->vcpis, next) {
4490		if (pos->port == port) {
4491			found = true;
4492			break;
4493		}
4494	}
4495	if (WARN_ON(!found)) {
4496		drm_err(mgr->dev, "no VCPI for [MST PORT:%p] found in mst state %p\n",
4497			port, &topology_state->base);
4498		return -EINVAL;
4499	}
4500
4501	drm_dbg_atomic(mgr->dev, "[MST PORT:%p] VCPI %d -> 0\n", port, pos->vcpi);
4502	if (pos->vcpi) {
4503		drm_dp_mst_put_port_malloc(port);
4504		pos->vcpi = 0;
4505		pos->pbn = 0;
4506	}
4507
4508	return 0;
4509}
4510EXPORT_SYMBOL(drm_dp_atomic_release_vcpi_slots);
4511
4512/**
4513 * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
4514 * @mgr: manager for this port
4515 * @port: port to allocate a virtual channel for.
4516 * @pbn: payload bandwidth number to request
4517 * @slots: returned number of slots for this PBN.
4518 */
4519bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4520			      struct drm_dp_mst_port *port, int pbn, int slots)
4521{
4522	int ret;
4523
4524	if (slots < 0)
4525		return false;
4526
4527	port = drm_dp_mst_topology_get_port_validated(mgr, port);
4528	if (!port)
4529		return false;
4530
4531	if (port->vcpi.vcpi > 0) {
4532		drm_dbg_kms(mgr->dev,
4533			    "payload: vcpi %d already allocated for pbn %d - requested pbn %d\n",
4534			    port->vcpi.vcpi, port->vcpi.pbn, pbn);
4535		if (pbn == port->vcpi.pbn) {
4536			drm_dp_mst_topology_put_port(port);
4537			return true;
4538		}
4539	}
4540
4541	ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn, slots);
4542	if (ret) {
4543		drm_dbg_kms(mgr->dev, "failed to init vcpi slots=%d max=63 ret=%d\n",
4544			    DIV_ROUND_UP(pbn, mgr->pbn_div), ret);
4545		drm_dp_mst_topology_put_port(port);
4546		goto out;
4547	}
4548	drm_dbg_kms(mgr->dev, "initing vcpi for pbn=%d slots=%d\n", pbn, port->vcpi.num_slots);
4549
4550	/* Keep port allocated until its payload has been removed */
4551	drm_dp_mst_get_port_malloc(port);
4552	drm_dp_mst_topology_put_port(port);
4553	return true;
4554out:
4555	return false;
4556}
4557EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
4558
4559int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4560{
4561	int slots = 0;
4562
4563	port = drm_dp_mst_topology_get_port_validated(mgr, port);
4564	if (!port)
4565		return slots;
4566
4567	slots = port->vcpi.num_slots;
4568	drm_dp_mst_topology_put_port(port);
4569	return slots;
4570}
4571EXPORT_SYMBOL(drm_dp_mst_get_vcpi_slots);
4572
4573/**
4574 * drm_dp_mst_reset_vcpi_slots() - Reset number of slots to 0 for VCPI
4575 * @mgr: manager for this port
4576 * @port: unverified pointer to a port.
4577 *
4578 * This just resets the number of slots for the ports VCPI for later programming.
4579 */
4580void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
4581{
4582	/*
4583	 * A port with VCPI will remain allocated until its VCPI is
4584	 * released, no verified ref needed
4585	 */
4586
4587	port->vcpi.num_slots = 0;
4588}
4589EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
4590
4591/**
4592 * drm_dp_mst_deallocate_vcpi() - deallocate a VCPI
4593 * @mgr: manager for this port
4594 * @port: port to deallocate vcpi for
4595 *
4596 * This can be called unconditionally, regardless of whether
4597 * drm_dp_mst_allocate_vcpi() succeeded or not.
4598 */
4599void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
4600				struct drm_dp_mst_port *port)
4601{
4602	bool skip;
4603
4604	if (!port->vcpi.vcpi)
4605		return;
4606
4607	mutex_lock(&mgr->lock);
4608	skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
4609	mutex_unlock(&mgr->lock);
4610
4611	if (skip)
4612		return;
4613
4614	drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
4615	port->vcpi.num_slots = 0;
4616	port->vcpi.pbn = 0;
4617	port->vcpi.aligned_pbn = 0;
4618	port->vcpi.vcpi = 0;
4619	drm_dp_mst_put_port_malloc(port);
4620}
4621EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
4622
4623static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
4624				     int id, struct drm_dp_payload *payload)
4625{
4626	u8 payload_alloc[3], status;
4627	int ret;
4628	int retries = 0;
4629
4630	drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
4631			   DP_PAYLOAD_TABLE_UPDATED);
4632
4633	payload_alloc[0] = id;
4634	payload_alloc[1] = payload->start_slot;
4635	payload_alloc[2] = payload->num_slots;
4636
4637	ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
4638	if (ret != 3) {
4639		drm_dbg_kms(mgr->dev, "failed to write payload allocation %d\n", ret);
4640		goto fail;
4641	}
4642
4643retry:
4644	ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4645	if (ret < 0) {
4646		drm_dbg_kms(mgr->dev, "failed to read payload table status %d\n", ret);
4647		goto fail;
4648	}
4649
4650	if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
4651		retries++;
4652		if (retries < 20) {
4653			usleep_range(10000, 20000);
4654			goto retry;
4655		}
4656		drm_dbg_kms(mgr->dev, "status not set after read payload table status %d\n",
4657			    status);
4658		ret = -EINVAL;
4659		goto fail;
4660	}
4661	ret = 0;
4662fail:
4663	return ret;
4664}
4665
4666static int do_get_act_status(struct drm_dp_aux *aux)
4667{
4668	int ret;
4669	u8 status;
4670
4671	ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
4672	if (ret < 0)
4673		return ret;
4674
4675	return status;
4676}
4677
4678/**
4679 * drm_dp_check_act_status() - Polls for ACT handled status.
4680 * @mgr: manager to use
4681 *
4682 * Tries waiting for the MST hub to finish updating it's payload table by
4683 * polling for the ACT handled bit for up to 3 seconds (yes-some hubs really
4684 * take that long).
4685 *
4686 * Returns:
4687 * 0 if the ACT was handled in time, negative error code on failure.
4688 */
4689int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
4690{
4691	/*
4692	 * There doesn't seem to be any recommended retry count or timeout in
4693	 * the MST specification. Since some hubs have been observed to take
4694	 * over 1 second to update their payload allocations under certain
4695	 * conditions, we use a rather large timeout value.
4696	 */
4697	const int timeout_ms = 3000;
4698	int ret, status;
4699
4700	ret = readx_poll_timeout(do_get_act_status, mgr->aux, status,
4701				 status & DP_PAYLOAD_ACT_HANDLED || status < 0,
4702				 200, timeout_ms * USEC_PER_MSEC);
4703	if (ret < 0 && status >= 0) {
4704		drm_err(mgr->dev, "Failed to get ACT after %dms, last status: %02x\n",
4705			timeout_ms, status);
4706		return -EINVAL;
4707	} else if (status < 0) {
4708		/*
4709		 * Failure here isn't unexpected - the hub may have
4710		 * just been unplugged
4711		 */
4712		drm_dbg_kms(mgr->dev, "Failed to read payload table status: %d\n", status);
4713		return status;
4714	}
4715
4716	return 0;
4717}
4718EXPORT_SYMBOL(drm_dp_check_act_status);
4719
4720/**
4721 * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
4722 * @clock: dot clock for the mode
4723 * @bpp: bpp for the mode.
4724 * @dsc: DSC mode. If true, bpp has units of 1/16 of a bit per pixel
4725 *
4726 * This uses the formula in the spec to calculate the PBN value for a mode.
4727 */
4728int drm_dp_calc_pbn_mode(int clock, int bpp, bool dsc)
4729{
4730	/*
4731	 * margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006
4732	 * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on
4733	 * common multiplier to render an integer PBN for all link rate/lane
4734	 * counts combinations
4735	 * calculate
4736	 * peak_kbps *= (1006/1000)
4737	 * peak_kbps *= (64/54)
4738	 * peak_kbps *= 8    convert to bytes
4739	 *
4740	 * If the bpp is in units of 1/16, further divide by 16. Put this
4741	 * factor in the numerator rather than the denominator to avoid
4742	 * integer overflow
4743	 */
4744
4745	if (dsc)
4746		return DIV_ROUND_UP_ULL(mul_u32_u32(clock * (bpp / 16), 64 * 1006),
4747					8 * 54 * 1000 * 1000);
4748
4749	return DIV_ROUND_UP_ULL(mul_u32_u32(clock * bpp, 64 * 1006),
4750				8 * 54 * 1000 * 1000);
4751}
4752EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
4753
4754/* we want to kick the TX after we've ack the up/down IRQs. */
4755static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
4756{
4757	queue_work(system_long_wq, &mgr->tx_work);
4758}
4759
4760/*
4761 * Helper function for parsing DP device types into convenient strings
4762 * for use with dp_mst_topology
4763 */
4764static const char *pdt_to_string(u8 pdt)
4765{
4766	switch (pdt) {
4767	case DP_PEER_DEVICE_NONE:
4768		return "NONE";
4769	case DP_PEER_DEVICE_SOURCE_OR_SST:
4770		return "SOURCE OR SST";
4771	case DP_PEER_DEVICE_MST_BRANCHING:
4772		return "MST BRANCHING";
4773	case DP_PEER_DEVICE_SST_SINK:
4774		return "SST SINK";
4775	case DP_PEER_DEVICE_DP_LEGACY_CONV:
4776		return "DP LEGACY CONV";
4777	default:
4778		return "ERR";
4779	}
4780}
4781
4782static void drm_dp_mst_dump_mstb(struct seq_file *m,
4783				 struct drm_dp_mst_branch *mstb)
4784{
4785	struct drm_dp_mst_port *port;
4786	int tabs = mstb->lct;
4787	char prefix[10];
4788	int i;
4789
4790	for (i = 0; i < tabs; i++)
4791		prefix[i] = '\t';
4792	prefix[i] = '\0';
4793
4794	seq_printf(m, "%smstb - [%p]: num_ports: %d\n", prefix, mstb, mstb->num_ports);
4795	list_for_each_entry(port, &mstb->ports, next) {
4796		seq_printf(m, "%sport %d - [%p] (%s - %s): ddps: %d, ldps: %d, sdp: %d/%d, fec: %s, conn: %p\n", 
4797			   prefix,
4798			   port->port_num,
4799			   port,
4800			   port->input ? "input" : "output",
4801			   pdt_to_string(port->pdt),
4802			   port->ddps,
4803			   port->ldps,
4804			   port->num_sdp_streams,
4805			   port->num_sdp_stream_sinks,
4806			   port->fec_capable ? "true" : "false",
4807			   port->connector);
4808		if (port->mstb)
4809			drm_dp_mst_dump_mstb(m, port->mstb);
4810	}
4811}
4812
4813#define DP_PAYLOAD_TABLE_SIZE		64
4814
4815static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
4816				  char *buf)
4817{
4818	int i;
4819
4820	for (i = 0; i < DP_PAYLOAD_TABLE_SIZE; i += 16) {
4821		if (drm_dp_dpcd_read(mgr->aux,
4822				     DP_PAYLOAD_TABLE_UPDATE_STATUS + i,
4823				     &buf[i], 16) != 16)
4824			return false;
4825	}
4826	return true;
4827}
4828
4829static void fetch_monitor_name(struct drm_dp_mst_topology_mgr *mgr,
4830			       struct drm_dp_mst_port *port, char *name,
4831			       int namelen)
4832{
4833	struct edid *mst_edid;
4834
4835	mst_edid = drm_dp_mst_get_edid(port->connector, mgr, port);
4836	drm_edid_get_monitor_name(mst_edid, name, namelen);
4837}
4838
4839/**
4840 * drm_dp_mst_dump_topology(): dump topology to seq file.
4841 * @m: seq_file to dump output to
4842 * @mgr: manager to dump current topology for.
4843 *
4844 * helper to dump MST topology to a seq file for debugfs.
4845 */
4846void drm_dp_mst_dump_topology(struct seq_file *m,
4847			      struct drm_dp_mst_topology_mgr *mgr)
4848{
4849	int i;
4850	struct drm_dp_mst_port *port;
4851
4852	mutex_lock(&mgr->lock);
4853	if (mgr->mst_primary)
4854		drm_dp_mst_dump_mstb(m, mgr->mst_primary);
4855
4856	/* dump VCPIs */
4857	mutex_unlock(&mgr->lock);
4858
4859	mutex_lock(&mgr->payload_lock);
4860	seq_printf(m, "\n*** VCPI Info ***\n");
4861	seq_printf(m, "payload_mask: %lx, vcpi_mask: %lx, max_payloads: %d\n", mgr->payload_mask, mgr->vcpi_mask, mgr->max_payloads);
4862
4863	seq_printf(m, "\n|   idx   |  port # |  vcp_id | # slots |     sink name     |\n");
4864	for (i = 0; i < mgr->max_payloads; i++) {
4865		if (mgr->proposed_vcpis[i]) {
4866			char name[14];
4867
4868			port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
4869			fetch_monitor_name(mgr, port, name, sizeof(name));
4870			seq_printf(m, "%10d%10d%10d%10d%20s\n",
4871				   i,
4872				   port->port_num,
4873				   port->vcpi.vcpi,
4874				   port->vcpi.num_slots,
4875				   (*name != 0) ? name : "Unknown");
4876		} else
4877			seq_printf(m, "%6d - Unused\n", i);
4878	}
4879	seq_printf(m, "\n*** Payload Info ***\n");
4880	seq_printf(m, "|   idx   |  state  |  start slot  | # slots |\n");
4881	for (i = 0; i < mgr->max_payloads; i++) {
4882		seq_printf(m, "%10d%10d%15d%10d\n",
4883			   i,
4884			   mgr->payloads[i].payload_state,
4885			   mgr->payloads[i].start_slot,
4886			   mgr->payloads[i].num_slots);
4887	}
4888	mutex_unlock(&mgr->payload_lock);
4889
4890	seq_printf(m, "\n*** DPCD Info ***\n");
4891	mutex_lock(&mgr->lock);
4892	if (mgr->mst_primary) {
4893		u8 buf[DP_PAYLOAD_TABLE_SIZE];
4894		int ret;
4895
4896		ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, buf, DP_RECEIVER_CAP_SIZE);
4897		if (ret) {
4898			seq_printf(m, "dpcd read failed\n");
4899			goto out;
4900		}
4901		seq_printf(m, "dpcd: %*ph\n", DP_RECEIVER_CAP_SIZE, buf);
4902
4903		ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
4904		if (ret) {
4905			seq_printf(m, "faux/mst read failed\n");
4906			goto out;
4907		}
4908		seq_printf(m, "faux/mst: %*ph\n", 2, buf);
4909
4910		ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
4911		if (ret) {
4912			seq_printf(m, "mst ctrl read failed\n");
4913			goto out;
4914		}
4915		seq_printf(m, "mst ctrl: %*ph\n", 1, buf);
4916
4917		/* dump the standard OUI branch header */
4918		ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
4919		if (ret) {
4920			seq_printf(m, "branch oui read failed\n");
4921			goto out;
4922		}
4923		seq_printf(m, "branch oui: %*phN devid: ", 3, buf);
4924
4925		for (i = 0x3; i < 0x8 && buf[i]; i++)
4926			seq_printf(m, "%c", buf[i]);
4927		seq_printf(m, " revision: hw: %x.%x sw: %x.%x\n",
4928			   buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]);
4929		if (dump_dp_payload_table(mgr, buf))
4930			seq_printf(m, "payload table: %*ph\n", DP_PAYLOAD_TABLE_SIZE, buf);
4931	}
4932
4933out:
4934	mutex_unlock(&mgr->lock);
4935
4936}
4937EXPORT_SYMBOL(drm_dp_mst_dump_topology);
4938
4939static void drm_dp_tx_work(struct work_struct *work)
4940{
4941	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
4942
4943	mutex_lock(&mgr->qlock);
4944	if (!list_empty(&mgr->tx_msg_downq))
4945		process_single_down_tx_qlock(mgr);
4946	mutex_unlock(&mgr->qlock);
4947}
4948
4949static inline void
4950drm_dp_delayed_destroy_port(struct drm_dp_mst_port *port)
4951{
4952	drm_dp_port_set_pdt(port, DP_PEER_DEVICE_NONE, port->mcs);
4953
4954	if (port->connector) {
4955		drm_connector_unregister(port->connector);
4956		drm_connector_put(port->connector);
4957	}
4958
4959	drm_dp_mst_put_port_malloc(port);
4960}
4961
4962static inline void
4963drm_dp_delayed_destroy_mstb(struct drm_dp_mst_branch *mstb)
4964{
4965	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
4966	struct drm_dp_mst_port *port, *port_tmp;
4967	struct drm_dp_sideband_msg_tx *txmsg, *txmsg_tmp;
4968	bool wake_tx = false;
4969
4970	mutex_lock(&mgr->lock);
4971	list_for_each_entry_safe(port, port_tmp, &mstb->ports, next) {
4972		list_del(&port->next);
4973		drm_dp_mst_topology_put_port(port);
4974	}
4975	mutex_unlock(&mgr->lock);
4976
4977	/* drop any tx slot msg */
4978	mutex_lock(&mstb->mgr->qlock);
4979	list_for_each_entry_safe(txmsg, txmsg_tmp, &mgr->tx_msg_downq, next) {
4980		if (txmsg->dst != mstb)
4981			continue;
4982
4983		txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
4984		list_del(&txmsg->next);
4985		wake_tx = true;
4986	}
4987	mutex_unlock(&mstb->mgr->qlock);
4988
4989	if (wake_tx)
4990		wake_up_all(&mstb->mgr->tx_waitq);
4991
4992	drm_dp_mst_put_mstb_malloc(mstb);
4993}
4994
4995static void drm_dp_delayed_destroy_work(struct work_struct *work)
4996{
4997	struct drm_dp_mst_topology_mgr *mgr =
4998		container_of(work, struct drm_dp_mst_topology_mgr,
4999			     delayed_destroy_work);
5000	bool send_hotplug = false, go_again;
5001
5002	/*
5003	 * Not a regular list traverse as we have to drop the destroy
5004	 * connector lock before destroying the mstb/port, to avoid AB->BA
5005	 * ordering between this lock and the config mutex.
5006	 */
5007	do {
5008		go_again = false;
5009
5010		for (;;) {
5011			struct drm_dp_mst_branch *mstb;
5012
5013			mutex_lock(&mgr->delayed_destroy_lock);
5014			mstb = list_first_entry_or_null(&mgr->destroy_branch_device_list,
5015							struct drm_dp_mst_branch,
5016							destroy_next);
5017			if (mstb)
5018				list_del(&mstb->destroy_next);
5019			mutex_unlock(&mgr->delayed_destroy_lock);
5020
5021			if (!mstb)
5022				break;
5023
5024			drm_dp_delayed_destroy_mstb(mstb);
5025			go_again = true;
5026		}
5027
5028		for (;;) {
5029			struct drm_dp_mst_port *port;
5030
5031			mutex_lock(&mgr->delayed_destroy_lock);
5032			port = list_first_entry_or_null(&mgr->destroy_port_list,
5033							struct drm_dp_mst_port,
5034							next);
5035			if (port)
5036				list_del(&port->next);
5037			mutex_unlock(&mgr->delayed_destroy_lock);
5038
5039			if (!port)
5040				break;
5041
5042			drm_dp_delayed_destroy_port(port);
5043			send_hotplug = true;
5044			go_again = true;
5045		}
5046	} while (go_again);
5047
5048	if (send_hotplug)
5049		drm_kms_helper_hotplug_event(mgr->dev);
5050}
5051
5052static struct drm_private_state *
5053drm_dp_mst_duplicate_state(struct drm_private_obj *obj)
5054{
5055	struct drm_dp_mst_topology_state *state, *old_state =
5056		to_dp_mst_topology_state(obj->state);
5057	struct drm_dp_vcpi_allocation *pos, *vcpi;
5058
5059	state = kmemdup(old_state, sizeof(*state), GFP_KERNEL);
5060	if (!state)
5061		return NULL;
5062
5063	__drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
5064
5065	INIT_LIST_HEAD(&state->vcpis);
5066
5067	list_for_each_entry(pos, &old_state->vcpis, next) {
5068		/* Prune leftover freed VCPI allocations */
5069		if (!pos->vcpi)
5070			continue;
5071
5072		vcpi = kmemdup(pos, sizeof(*vcpi), GFP_KERNEL);
5073		if (!vcpi)
5074			goto fail;
5075
5076		drm_dp_mst_get_port_malloc(vcpi->port);
5077		list_add(&vcpi->next, &state->vcpis);
5078	}
5079
5080	return &state->base;
5081
5082fail:
5083	list_for_each_entry_safe(pos, vcpi, &state->vcpis, next) {
5084		drm_dp_mst_put_port_malloc(pos->port);
5085		kfree(pos);
5086	}
5087	kfree(state);
5088
5089	return NULL;
5090}
5091
5092static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
5093				     struct drm_private_state *state)
5094{
5095	struct drm_dp_mst_topology_state *mst_state =
5096		to_dp_mst_topology_state(state);
5097	struct drm_dp_vcpi_allocation *pos, *tmp;
5098
5099	list_for_each_entry_safe(pos, tmp, &mst_state->vcpis, next) {
5100		/* We only keep references to ports with non-zero VCPIs */
5101		if (pos->vcpi)
5102			drm_dp_mst_put_port_malloc(pos->port);
5103		kfree(pos);
5104	}
5105
5106	kfree(mst_state);
5107}
5108
5109static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
5110						 struct drm_dp_mst_branch *branch)
5111{
5112	while (port->parent) {
5113		if (port->parent == branch)
5114			return true;
5115
5116		if (port->parent->port_parent)
5117			port = port->parent->port_parent;
5118		else
5119			break;
5120	}
5121	return false;
5122}
5123
5124static int
5125drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5126				      struct drm_dp_mst_topology_state *state);
5127
5128static int
5129drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb,
5130				      struct drm_dp_mst_topology_state *state)
5131{
5132	struct drm_dp_vcpi_allocation *vcpi;
5133	struct drm_dp_mst_port *port;
5134	int pbn_used = 0, ret;
5135	bool found = false;
5136
5137	/* Check that we have at least one port in our state that's downstream
5138	 * of this branch, otherwise we can skip this branch
5139	 */
5140	list_for_each_entry(vcpi, &state->vcpis, next) {
5141		if (!vcpi->pbn ||
5142		    !drm_dp_mst_port_downstream_of_branch(vcpi->port, mstb))
5143			continue;
5144
5145		found = true;
5146		break;
5147	}
5148	if (!found)
5149		return 0;
5150
5151	if (mstb->port_parent)
5152		drm_dbg_atomic(mstb->mgr->dev,
5153			       "[MSTB:%p] [MST PORT:%p] Checking bandwidth limits on [MSTB:%p]\n",
5154			       mstb->port_parent->parent, mstb->port_parent, mstb);
5155	else
5156		drm_dbg_atomic(mstb->mgr->dev, "[MSTB:%p] Checking bandwidth limits\n", mstb);
5157
5158	list_for_each_entry(port, &mstb->ports, next) {
5159		ret = drm_dp_mst_atomic_check_port_bw_limit(port, state);
5160		if (ret < 0)
5161			return ret;
5162
5163		pbn_used += ret;
5164	}
5165
5166	return pbn_used;
5167}
5168
5169static int
5170drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
5171				      struct drm_dp_mst_topology_state *state)
5172{
5173	struct drm_dp_vcpi_allocation *vcpi;
5174	int pbn_used = 0;
5175
5176	if (port->pdt == DP_PEER_DEVICE_NONE)
5177		return 0;
5178
5179	if (drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
5180		bool found = false;
5181
5182		list_for_each_entry(vcpi, &state->vcpis, next) {
5183			if (vcpi->port != port)
5184				continue;
5185			if (!vcpi->pbn)
5186				return 0;
5187
5188			found = true;
5189			break;
5190		}
5191		if (!found)
5192			return 0;
5193
5194		/*
5195		 * This could happen if the sink deasserted its HPD line, but
5196		 * the branch device still reports it as attached (PDT != NONE).
5197		 */
5198		if (!port->full_pbn) {
5199			drm_dbg_atomic(port->mgr->dev,
5200				       "[MSTB:%p] [MST PORT:%p] no BW available for the port\n",
5201				       port->parent, port);
5202			return -EINVAL;
5203		}
5204
5205		pbn_used = vcpi->pbn;
5206	} else {
5207		pbn_used = drm_dp_mst_atomic_check_mstb_bw_limit(port->mstb,
5208								 state);
5209		if (pbn_used <= 0)
5210			return pbn_used;
5211	}
5212
5213	if (pbn_used > port->full_pbn) {
5214		drm_dbg_atomic(port->mgr->dev,
5215			       "[MSTB:%p] [MST PORT:%p] required PBN of %d exceeds port limit of %d\n",
5216			       port->parent, port, pbn_used, port->full_pbn);
5217		return -ENOSPC;
5218	}
5219
5220	drm_dbg_atomic(port->mgr->dev, "[MSTB:%p] [MST PORT:%p] uses %d out of %d PBN\n",
5221		       port->parent, port, pbn_used, port->full_pbn);
5222
5223	return pbn_used;
5224}
5225
5226static inline int
5227drm_dp_mst_atomic_check_vcpi_alloc_limit(struct drm_dp_mst_topology_mgr *mgr,
5228					 struct drm_dp_mst_topology_state *mst_state)
5229{
5230	struct drm_dp_vcpi_allocation *vcpi;
5231	int avail_slots = 63, payload_count = 0;
5232
5233	list_for_each_entry(vcpi, &mst_state->vcpis, next) {
5234		/* Releasing VCPI is always OK-even if the port is gone */
5235		if (!vcpi->vcpi) {
5236			drm_dbg_atomic(mgr->dev, "[MST PORT:%p] releases all VCPI slots\n",
5237				       vcpi->port);
5238			continue;
5239		}
5240
5241		drm_dbg_atomic(mgr->dev, "[MST PORT:%p] requires %d vcpi slots\n",
5242			       vcpi->port, vcpi->vcpi);
5243
5244		avail_slots -= vcpi->vcpi;
5245		if (avail_slots < 0) {
5246			drm_dbg_atomic(mgr->dev,
5247				       "[MST PORT:%p] not enough VCPI slots in mst state %p (avail=%d)\n",
5248				       vcpi->port, mst_state, avail_slots + vcpi->vcpi);
5249			return -ENOSPC;
5250		}
5251
5252		if (++payload_count > mgr->max_payloads) {
5253			drm_dbg_atomic(mgr->dev,
5254				       "[MST MGR:%p] state %p has too many payloads (max=%d)\n",
5255				       mgr, mst_state, mgr->max_payloads);
5256			return -EINVAL;
5257		}
5258	}
5259	drm_dbg_atomic(mgr->dev, "[MST MGR:%p] mst state %p VCPI avail=%d used=%d\n",
5260		       mgr, mst_state, avail_slots, 63 - avail_slots);
5261
5262	return 0;
5263}
5264
5265/**
5266 * drm_dp_mst_add_affected_dsc_crtcs
5267 * @state: Pointer to the new struct drm_dp_mst_topology_state
5268 * @mgr: MST topology manager
5269 *
5270 * Whenever there is a change in mst topology
5271 * DSC configuration would have to be recalculated
5272 * therefore we need to trigger modeset on all affected
5273 * CRTCs in that topology
5274 *
5275 * See also:
5276 * drm_dp_mst_atomic_enable_dsc()
5277 */
5278int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state, struct drm_dp_mst_topology_mgr *mgr)
5279{
5280	struct drm_dp_mst_topology_state *mst_state;
5281	struct drm_dp_vcpi_allocation *pos;
5282	struct drm_connector *connector;
5283	struct drm_connector_state *conn_state;
5284	struct drm_crtc *crtc;
5285	struct drm_crtc_state *crtc_state;
5286
5287	mst_state = drm_atomic_get_mst_topology_state(state, mgr);
5288
5289	if (IS_ERR(mst_state))
5290		return -EINVAL;
5291
5292	list_for_each_entry(pos, &mst_state->vcpis, next) {
5293
5294		connector = pos->port->connector;
5295
5296		if (!connector)
5297			return -EINVAL;
5298
5299		conn_state = drm_atomic_get_connector_state(state, connector);
5300
5301		if (IS_ERR(conn_state))
5302			return PTR_ERR(conn_state);
5303
5304		crtc = conn_state->crtc;
5305
5306		if (!crtc)
5307			continue;
5308
5309		if (!drm_dp_mst_dsc_aux_for_port(pos->port))
5310			continue;
5311
5312		crtc_state = drm_atomic_get_crtc_state(mst_state->base.state, crtc);
5313
5314		if (IS_ERR(crtc_state))
5315			return PTR_ERR(crtc_state);
5316
5317		drm_dbg_atomic(mgr->dev, "[MST MGR:%p] Setting mode_changed flag on CRTC %p\n",
5318			       mgr, crtc);
5319
5320		crtc_state->mode_changed = true;
5321	}
5322	return 0;
5323}
5324EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
5325
5326/**
5327 * drm_dp_mst_atomic_enable_dsc - Set DSC Enable Flag to On/Off
5328 * @state: Pointer to the new drm_atomic_state
5329 * @port: Pointer to the affected MST Port
5330 * @pbn: Newly recalculated bw required for link with DSC enabled
5331 * @pbn_div: Divider to calculate correct number of pbn per slot
5332 * @enable: Boolean flag to enable or disable DSC on the port
5333 *
5334 * This function enables DSC on the given Port
5335 * by recalculating its vcpi from pbn provided
5336 * and sets dsc_enable flag to keep track of which
5337 * ports have DSC enabled
5338 *
5339 */
5340int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
5341				 struct drm_dp_mst_port *port,
5342				 int pbn, int pbn_div,
5343				 bool enable)
5344{
5345	struct drm_dp_mst_topology_state *mst_state;
5346	struct drm_dp_vcpi_allocation *pos;
5347	bool found = false;
5348	int vcpi = 0;
5349
5350	mst_state = drm_atomic_get_mst_topology_state(state, port->mgr);
5351
5352	if (IS_ERR(mst_state))
5353		return PTR_ERR(mst_state);
5354
5355	list_for_each_entry(pos, &mst_state->vcpis, next) {
5356		if (pos->port == port) {
5357			found = true;
5358			break;
5359		}
5360	}
5361
5362	if (!found) {
5363		drm_dbg_atomic(state->dev,
5364			       "[MST PORT:%p] Couldn't find VCPI allocation in mst state %p\n",
5365			       port, mst_state);
5366		return -EINVAL;
5367	}
5368
5369	if (pos->dsc_enabled == enable) {
5370		drm_dbg_atomic(state->dev,
5371			       "[MST PORT:%p] DSC flag is already set to %d, returning %d VCPI slots\n",
5372			       port, enable, pos->vcpi);
5373		vcpi = pos->vcpi;
5374	}
5375
5376	if (enable) {
5377		vcpi = drm_dp_atomic_find_vcpi_slots(state, port->mgr, port, pbn, pbn_div);
5378		drm_dbg_atomic(state->dev,
5379			       "[MST PORT:%p] Enabling DSC flag, reallocating %d VCPI slots on the port\n",
5380			       port, vcpi);
5381		if (vcpi < 0)
5382			return -EINVAL;
5383	}
5384
5385	pos->dsc_enabled = enable;
5386
5387	return vcpi;
5388}
5389EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
5390/**
5391 * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
5392 * atomic update is valid
5393 * @state: Pointer to the new &struct drm_dp_mst_topology_state
5394 *
5395 * Checks the given topology state for an atomic update to ensure that it's
5396 * valid. This includes checking whether there's enough bandwidth to support
5397 * the new VCPI allocations in the atomic update.
5398 *
5399 * Any atomic drivers supporting DP MST must make sure to call this after
5400 * checking the rest of their state in their
5401 * &drm_mode_config_funcs.atomic_check() callback.
5402 *
5403 * See also:
5404 * drm_dp_atomic_find_vcpi_slots()
5405 * drm_dp_atomic_release_vcpi_slots()
5406 *
5407 * Returns:
5408 *
5409 * 0 if the new state is valid, negative error code otherwise.
5410 */
5411int drm_dp_mst_atomic_check(struct drm_atomic_state *state)
5412{
5413	struct drm_dp_mst_topology_mgr *mgr;
5414	struct drm_dp_mst_topology_state *mst_state;
5415	int i, ret = 0;
5416
5417	for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
5418		if (!mgr->mst_state)
5419			continue;
5420
5421		ret = drm_dp_mst_atomic_check_vcpi_alloc_limit(mgr, mst_state);
5422		if (ret)
5423			break;
5424
5425		mutex_lock(&mgr->lock);
5426		ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary,
5427							    mst_state);
5428		mutex_unlock(&mgr->lock);
5429		if (ret < 0)
5430			break;
5431		else
5432			ret = 0;
5433	}
5434
5435	return ret;
5436}
5437EXPORT_SYMBOL(drm_dp_mst_atomic_check);
5438
5439const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs = {
5440	.atomic_duplicate_state = drm_dp_mst_duplicate_state,
5441	.atomic_destroy_state = drm_dp_mst_destroy_state,
5442};
5443EXPORT_SYMBOL(drm_dp_mst_topology_state_funcs);
5444
5445/**
5446 * drm_atomic_get_mst_topology_state: get MST topology state
5447 *
5448 * @state: global atomic state
5449 * @mgr: MST topology manager, also the private object in this case
5450 *
5451 * This function wraps drm_atomic_get_priv_obj_state() passing in the MST atomic
5452 * state vtable so that the private object state returned is that of a MST
5453 * topology object. Also, drm_atomic_get_private_obj_state() expects the caller
5454 * to care of the locking, so warn if don't hold the connection_mutex.
5455 *
5456 * RETURNS:
5457 *
5458 * The MST topology state or error pointer.
5459 */
5460struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
5461								    struct drm_dp_mst_topology_mgr *mgr)
5462{
5463	return to_dp_mst_topology_state(drm_atomic_get_private_obj_state(state, &mgr->base));
5464}
5465EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
5466
5467/**
5468 * drm_dp_mst_topology_mgr_init - initialise a topology manager
5469 * @mgr: manager struct to initialise
5470 * @dev: device providing this structure - for i2c addition.
5471 * @aux: DP helper aux channel to talk to this device
5472 * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
5473 * @max_payloads: maximum number of payloads this GPU can source
5474 * @max_lane_count: maximum number of lanes this GPU supports
5475 * @max_link_rate: maximum link rate per lane this GPU supports in kHz
5476 * @conn_base_id: the connector object ID the MST device is connected to.
5477 *
5478 * Return 0 for success, or negative error code on failure
5479 */
5480int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
5481				 struct drm_device *dev, struct drm_dp_aux *aux,
5482				 int max_dpcd_transaction_bytes, int max_payloads,
5483				 int max_lane_count, int max_link_rate,
5484				 int conn_base_id)
5485{
5486	struct drm_dp_mst_topology_state *mst_state;
5487
5488	mutex_init(&mgr->lock);
5489	mutex_init(&mgr->qlock);
5490	mutex_init(&mgr->payload_lock);
5491	mutex_init(&mgr->delayed_destroy_lock);
5492	mutex_init(&mgr->up_req_lock);
5493	mutex_init(&mgr->probe_lock);
5494#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5495	mutex_init(&mgr->topology_ref_history_lock);
5496#endif
5497	INIT_LIST_HEAD(&mgr->tx_msg_downq);
5498	INIT_LIST_HEAD(&mgr->destroy_port_list);
5499	INIT_LIST_HEAD(&mgr->destroy_branch_device_list);
5500	INIT_LIST_HEAD(&mgr->up_req_list);
5501
5502	/*
5503	 * delayed_destroy_work will be queued on a dedicated WQ, so that any
5504	 * requeuing will be also flushed when deiniting the topology manager.
5505	 */
5506	mgr->delayed_destroy_wq = alloc_ordered_workqueue("drm_dp_mst_wq", 0);
5507	if (mgr->delayed_destroy_wq == NULL)
5508		return -ENOMEM;
5509
5510	INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
5511	INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
5512	INIT_WORK(&mgr->delayed_destroy_work, drm_dp_delayed_destroy_work);
5513	INIT_WORK(&mgr->up_req_work, drm_dp_mst_up_req_work);
5514	init_waitqueue_head(&mgr->tx_waitq);
5515	mgr->dev = dev;
5516	mgr->aux = aux;
5517	mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
5518	mgr->max_payloads = max_payloads;
5519	mgr->max_lane_count = max_lane_count;
5520	mgr->max_link_rate = max_link_rate;
5521	mgr->conn_base_id = conn_base_id;
5522	if (max_payloads + 1 > sizeof(mgr->payload_mask) * 8 ||
5523	    max_payloads + 1 > sizeof(mgr->vcpi_mask) * 8)
5524		return -EINVAL;
5525	mgr->payloads = kcalloc(max_payloads, sizeof(struct drm_dp_payload), GFP_KERNEL);
5526	if (!mgr->payloads)
5527		return -ENOMEM;
5528	mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);
5529	if (!mgr->proposed_vcpis)
5530		return -ENOMEM;
5531	set_bit(0, &mgr->payload_mask);
5532
5533	mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);
5534	if (mst_state == NULL)
5535		return -ENOMEM;
5536
5537	mst_state->mgr = mgr;
5538	INIT_LIST_HEAD(&mst_state->vcpis);
5539
5540	drm_atomic_private_obj_init(dev, &mgr->base,
5541				    &mst_state->base,
5542				    &drm_dp_mst_topology_state_funcs);
5543
5544	return 0;
5545}
5546EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
5547
5548/**
5549 * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
5550 * @mgr: manager to destroy
5551 */
5552void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
5553{
5554	drm_dp_mst_topology_mgr_set_mst(mgr, false);
5555	flush_work(&mgr->work);
5556	/* The following will also drain any requeued work on the WQ. */
5557	if (mgr->delayed_destroy_wq) {
5558		destroy_workqueue(mgr->delayed_destroy_wq);
5559		mgr->delayed_destroy_wq = NULL;
5560	}
5561	mutex_lock(&mgr->payload_lock);
5562	kfree(mgr->payloads);
5563	mgr->payloads = NULL;
5564	kfree(mgr->proposed_vcpis);
5565	mgr->proposed_vcpis = NULL;
5566	mutex_unlock(&mgr->payload_lock);
5567	mgr->dev = NULL;
5568	mgr->aux = NULL;
5569	drm_atomic_private_obj_fini(&mgr->base);
5570	mgr->funcs = NULL;
5571
5572	mutex_destroy(&mgr->delayed_destroy_lock);
5573	mutex_destroy(&mgr->payload_lock);
5574	mutex_destroy(&mgr->qlock);
5575	mutex_destroy(&mgr->lock);
5576	mutex_destroy(&mgr->up_req_lock);
5577	mutex_destroy(&mgr->probe_lock);
5578#if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
5579	mutex_destroy(&mgr->topology_ref_history_lock);
5580#endif
5581}
5582EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
5583
5584static bool remote_i2c_read_ok(const struct i2c_msg msgs[], int num)
5585{
5586	int i;
5587
5588	if (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)
5589		return false;
5590
5591	for (i = 0; i < num - 1; i++) {
5592		if (msgs[i].flags & I2C_M_RD ||
5593		    msgs[i].len > 0xff)
5594			return false;
5595	}
5596
5597	return msgs[num - 1].flags & I2C_M_RD &&
5598		msgs[num - 1].len <= 0xff;
5599}
5600
5601static bool remote_i2c_write_ok(const struct i2c_msg msgs[], int num)
5602{
5603	int i;
5604
5605	for (i = 0; i < num - 1; i++) {
5606		if (msgs[i].flags & I2C_M_RD || !(msgs[i].flags & I2C_M_STOP) ||
5607		    msgs[i].len > 0xff)
5608			return false;
5609	}
5610
5611	return !(msgs[num - 1].flags & I2C_M_RD) && msgs[num - 1].len <= 0xff;
5612}
5613
5614static int drm_dp_mst_i2c_read(struct drm_dp_mst_branch *mstb,
5615			       struct drm_dp_mst_port *port,
5616			       struct i2c_msg *msgs, int num)
5617{
5618	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5619	unsigned int i;
5620	struct drm_dp_sideband_msg_req_body msg;
5621	struct drm_dp_sideband_msg_tx *txmsg = NULL;
5622	int ret;
5623
5624	memset(&msg, 0, sizeof(msg));
5625	msg.req_type = DP_REMOTE_I2C_READ;
5626	msg.u.i2c_read.num_transactions = num - 1;
5627	msg.u.i2c_read.port_number = port->port_num;
5628	for (i = 0; i < num - 1; i++) {
5629		msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
5630		msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
5631		msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
5632		msg.u.i2c_read.transactions[i].no_stop_bit = !(msgs[i].flags & I2C_M_STOP);
5633	}
5634	msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
5635	msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
5636
5637	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5638	if (!txmsg) {
5639		ret = -ENOMEM;
5640		goto out;
5641	}
5642
5643	txmsg->dst = mstb;
5644	drm_dp_encode_sideband_req(&msg, txmsg);
5645
5646	drm_dp_queue_down_tx(mgr, txmsg);
5647
5648	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5649	if (ret > 0) {
5650
5651		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5652			ret = -EREMOTEIO;
5653			goto out;
5654		}
5655		if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
5656			ret = -EIO;
5657			goto out;
5658		}
5659		memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
5660		ret = num;
5661	}
5662out:
5663	kfree(txmsg);
5664	return ret;
5665}
5666
5667static int drm_dp_mst_i2c_write(struct drm_dp_mst_branch *mstb,
5668				struct drm_dp_mst_port *port,
5669				struct i2c_msg *msgs, int num)
5670{
5671	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5672	unsigned int i;
5673	struct drm_dp_sideband_msg_req_body msg;
5674	struct drm_dp_sideband_msg_tx *txmsg = NULL;
5675	int ret;
5676
5677	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
5678	if (!txmsg) {
5679		ret = -ENOMEM;
5680		goto out;
5681	}
5682	for (i = 0; i < num; i++) {
5683		memset(&msg, 0, sizeof(msg));
5684		msg.req_type = DP_REMOTE_I2C_WRITE;
5685		msg.u.i2c_write.port_number = port->port_num;
5686		msg.u.i2c_write.write_i2c_device_id = msgs[i].addr;
5687		msg.u.i2c_write.num_bytes = msgs[i].len;
5688		msg.u.i2c_write.bytes = msgs[i].buf;
5689
5690		memset(txmsg, 0, sizeof(*txmsg));
5691		txmsg->dst = mstb;
5692
5693		drm_dp_encode_sideband_req(&msg, txmsg);
5694		drm_dp_queue_down_tx(mgr, txmsg);
5695
5696		ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
5697		if (ret > 0) {
5698			if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
5699				ret = -EREMOTEIO;
5700				goto out;
5701			}
5702		} else {
5703			goto out;
5704		}
5705	}
5706	ret = num;
5707out:
5708	kfree(txmsg);
5709	return ret;
5710}
5711
5712/* I2C device */
5713static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter,
5714			       struct i2c_msg *msgs, int num)
5715{
5716	struct drm_dp_aux *aux = adapter->algo_data;
5717	struct drm_dp_mst_port *port =
5718		container_of(aux, struct drm_dp_mst_port, aux);
5719	struct drm_dp_mst_branch *mstb;
5720	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
5721	int ret;
5722
5723	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
5724	if (!mstb)
5725		return -EREMOTEIO;
5726
5727	if (remote_i2c_read_ok(msgs, num)) {
5728		ret = drm_dp_mst_i2c_read(mstb, port, msgs, num);
5729	} else if (remote_i2c_write_ok(msgs, num)) {
5730		ret = drm_dp_mst_i2c_write(mstb, port, msgs, num);
5731	} else {
5732		drm_dbg_kms(mgr->dev, "Unsupported I2C transaction for MST device\n");
5733		ret = -EIO;
5734	}
5735
5736	drm_dp_mst_topology_put_mstb(mstb);
5737	return ret;
5738}
5739
5740static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
5741{
5742	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
5743	       I2C_FUNC_SMBUS_READ_BLOCK_DATA |
5744	       I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
5745	       I2C_FUNC_10BIT_ADDR;
5746}
5747
5748static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
5749	.functionality = drm_dp_mst_i2c_functionality,
5750	.master_xfer = drm_dp_mst_i2c_xfer,
5751};
5752
5753/**
5754 * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
5755 * @port: The port to add the I2C bus on
5756 *
5757 * Returns 0 on success or a negative error code on failure.
5758 */
5759static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port)
5760{
5761	struct drm_dp_aux *aux = &port->aux;
5762	struct device *parent_dev = port->mgr->dev->dev;
5763
5764	aux->ddc.algo = &drm_dp_mst_i2c_algo;
5765	aux->ddc.algo_data = aux;
5766	aux->ddc.retries = 3;
5767
5768	aux->ddc.class = I2C_CLASS_DDC;
5769	aux->ddc.owner = THIS_MODULE;
5770	/* FIXME: set the kdev of the port's connector as parent */
5771	aux->ddc.dev.parent = parent_dev;
5772	aux->ddc.dev.of_node = parent_dev->of_node;
5773
5774	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(parent_dev),
5775		sizeof(aux->ddc.name));
5776
5777	return i2c_add_adapter(&aux->ddc);
5778}
5779
5780/**
5781 * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
5782 * @port: The port to remove the I2C bus from
5783 */
5784static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port)
5785{
5786	i2c_del_adapter(&port->aux.ddc);
5787}
5788
5789/**
5790 * drm_dp_mst_is_virtual_dpcd() - Is the given port a virtual DP Peer Device
5791 * @port: The port to check
5792 *
5793 * A single physical MST hub object can be represented in the topology
5794 * by multiple branches, with virtual ports between those branches.
5795 *
5796 * As of DP1.4, An MST hub with internal (virtual) ports must expose
5797 * certain DPCD registers over those ports. See sections 2.6.1.1.1
5798 * and 2.6.1.1.2 of Display Port specification v1.4 for details.
5799 *
5800 * May acquire mgr->lock
5801 *
5802 * Returns:
5803 * true if the port is a virtual DP peer device, false otherwise
5804 */
5805static bool drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port *port)
5806{
5807	struct drm_dp_mst_port *downstream_port;
5808
5809	if (!port || port->dpcd_rev < DP_DPCD_REV_14)
5810		return false;
5811
5812	/* Virtual DP Sink (Internal Display Panel) */
5813	if (port->port_num >= 8)
5814		return true;
5815
5816	/* DP-to-HDMI Protocol Converter */
5817	if (port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV &&
5818	    !port->mcs &&
5819	    port->ldps)
5820		return true;
5821
5822	/* DP-to-DP */
5823	mutex_lock(&port->mgr->lock);
5824	if (port->pdt == DP_PEER_DEVICE_MST_BRANCHING &&
5825	    port->mstb &&
5826	    port->mstb->num_ports == 2) {
5827		list_for_each_entry(downstream_port, &port->mstb->ports, next) {
5828			if (downstream_port->pdt == DP_PEER_DEVICE_SST_SINK &&
5829			    !downstream_port->input) {
5830				mutex_unlock(&port->mgr->lock);
5831				return true;
5832			}
5833		}
5834	}
5835	mutex_unlock(&port->mgr->lock);
5836
5837	return false;
5838}
5839
5840/**
5841 * drm_dp_mst_dsc_aux_for_port() - Find the correct aux for DSC
5842 * @port: The port to check. A leaf of the MST tree with an attached display.
5843 *
5844 * Depending on the situation, DSC may be enabled via the endpoint aux,
5845 * the immediately upstream aux, or the connector's physical aux.
5846 *
5847 * This is both the correct aux to read DSC_CAPABILITY and the
5848 * correct aux to write DSC_ENABLED.
5849 *
5850 * This operation can be expensive (up to four aux reads), so
5851 * the caller should cache the return.
5852 *
5853 * Returns:
5854 * NULL if DSC cannot be enabled on this port, otherwise the aux device
5855 */
5856struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
5857{
5858	struct drm_dp_mst_port *immediate_upstream_port;
5859	struct drm_dp_mst_port *fec_port;
5860	struct drm_dp_desc desc = {};
5861	u8 endpoint_fec;
5862	u8 endpoint_dsc;
5863
5864	if (!port)
5865		return NULL;
5866
5867	if (port->parent->port_parent)
5868		immediate_upstream_port = port->parent->port_parent;
5869	else
5870		immediate_upstream_port = NULL;
5871
5872	fec_port = immediate_upstream_port;
5873	while (fec_port) {
5874		/*
5875		 * Each physical link (i.e. not a virtual port) between the
5876		 * output and the primary device must support FEC
5877		 */
5878		if (!drm_dp_mst_is_virtual_dpcd(fec_port) &&
5879		    !fec_port->fec_capable)
5880			return NULL;
5881
5882		fec_port = fec_port->parent->port_parent;
5883	}
5884
5885	/* DP-to-DP peer device */
5886	if (drm_dp_mst_is_virtual_dpcd(immediate_upstream_port)) {
5887		u8 upstream_dsc;
5888
5889		if (drm_dp_dpcd_read(&port->aux,
5890				     DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5891			return NULL;
5892		if (drm_dp_dpcd_read(&port->aux,
5893				     DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5894			return NULL;
5895		if (drm_dp_dpcd_read(&immediate_upstream_port->aux,
5896				     DP_DSC_SUPPORT, &upstream_dsc, 1) != 1)
5897			return NULL;
5898
5899		/* Enpoint decompression with DP-to-DP peer device */
5900		if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5901		    (endpoint_fec & DP_FEC_CAPABLE) &&
5902		    (upstream_dsc & 0x2) /* DSC passthrough */)
5903			return &port->aux;
5904
5905		/* Virtual DPCD decompression with DP-to-DP peer device */
5906		return &immediate_upstream_port->aux;
5907	}
5908
5909	/* Virtual DPCD decompression with DP-to-HDMI or Virtual DP Sink */
5910	if (drm_dp_mst_is_virtual_dpcd(port))
5911		return &port->aux;
5912
5913	/*
5914	 * Synaptics quirk
5915	 * Applies to ports for which:
5916	 * - Physical aux has Synaptics OUI
5917	 * - DPv1.4 or higher
5918	 * - Port is on primary branch device
5919	 * - Not a VGA adapter (DP_DWN_STRM_PORT_TYPE_ANALOG)
5920	 */
5921	if (drm_dp_read_desc(port->mgr->aux, &desc, true))
5922		return NULL;
5923
5924	if (drm_dp_has_quirk(&desc, DP_DPCD_QUIRK_DSC_WITHOUT_VIRTUAL_DPCD) &&
5925	    port->mgr->dpcd[DP_DPCD_REV] >= DP_DPCD_REV_14 &&
5926	    port->parent == port->mgr->mst_primary) {
5927		u8 dpcd_ext[DP_RECEIVER_CAP_SIZE];
5928
5929		if (drm_dp_read_dpcd_caps(port->mgr->aux, dpcd_ext) < 0)
5930			return NULL;
5931
5932		if ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT) &&
5933		    ((dpcd_ext[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_TYPE_MASK)
5934		     != DP_DWN_STRM_PORT_TYPE_ANALOG))
5935			return port->mgr->aux;
5936	}
5937
5938	/*
5939	 * The check below verifies if the MST sink
5940	 * connected to the GPU is capable of DSC -
5941	 * therefore the endpoint needs to be
5942	 * both DSC and FEC capable.
5943	 */
5944	if (drm_dp_dpcd_read(&port->aux,
5945	   DP_DSC_SUPPORT, &endpoint_dsc, 1) != 1)
5946		return NULL;
5947	if (drm_dp_dpcd_read(&port->aux,
5948	   DP_FEC_CAPABILITY, &endpoint_fec, 1) != 1)
5949		return NULL;
5950	if ((endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED) &&
5951	   (endpoint_fec & DP_FEC_CAPABLE))
5952		return &port->aux;
5953
5954	return NULL;
5955}
5956EXPORT_SYMBOL(drm_dp_mst_dsc_aux_for_port);