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/delay.h>
  24#include <linux/errno.h>
  25#include <linux/i2c.h>
  26#include <linux/init.h>
  27#include <linux/kernel.h>
  28#include <linux/sched.h>
  29#include <linux/seq_file.h>
 
 
 
  30
 
  31#include <drm/drm_atomic.h>
  32#include <drm/drm_atomic_helper.h>
  33#include <drm/drm_dp_mst_helper.h>
  34#include <drm/drm_drv.h>
  35#include <drm/drm_fixed.h>
  36#include <drm/drm_print.h>
  37#include <drm/drm_probe_helper.h>
  38
  39#include "drm_crtc_helper_internal.h"
  40
  41/**
  42 * DOC: dp mst helper
  43 *
  44 * These functions contain parts of the DisplayPort 1.2a MultiStream Transport
  45 * protocol. The helpers contain a topology manager and bandwidth manager.
  46 * The helpers encapsulate the sending and received of sideband msgs.
  47 */
  48static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
  49				  char *buf);
  50static int test_calc_pbn_mode(void);
  51
  52static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port);
  53
  54static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
  55				     int id,
  56				     struct drm_dp_payload *payload);
  57
  58static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
  59				 struct drm_dp_mst_port *port,
  60				 int offset, int size, u8 *bytes);
  61static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
  62				  struct drm_dp_mst_port *port,
  63				  int offset, int size, u8 *bytes);
  64
  65static void drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
  66				     struct drm_dp_mst_branch *mstb);
  67static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
  68					   struct drm_dp_mst_branch *mstb,
  69					   struct drm_dp_mst_port *port);
  70static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
  71				 u8 *guid);
  72
  73static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux);
  74static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_aux *aux);
  75static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
  76
  77#define DP_STR(x) [DP_ ## x] = #x
  78
  79static const char *drm_dp_mst_req_type_str(u8 req_type)
  80{
  81	static const char * const req_type_str[] = {
  82		DP_STR(GET_MSG_TRANSACTION_VERSION),
  83		DP_STR(LINK_ADDRESS),
  84		DP_STR(CONNECTION_STATUS_NOTIFY),
  85		DP_STR(ENUM_PATH_RESOURCES),
  86		DP_STR(ALLOCATE_PAYLOAD),
  87		DP_STR(QUERY_PAYLOAD),
  88		DP_STR(RESOURCE_STATUS_NOTIFY),
  89		DP_STR(CLEAR_PAYLOAD_ID_TABLE),
  90		DP_STR(REMOTE_DPCD_READ),
  91		DP_STR(REMOTE_DPCD_WRITE),
  92		DP_STR(REMOTE_I2C_READ),
  93		DP_STR(REMOTE_I2C_WRITE),
  94		DP_STR(POWER_UP_PHY),
  95		DP_STR(POWER_DOWN_PHY),
  96		DP_STR(SINK_EVENT_NOTIFY),
  97		DP_STR(QUERY_STREAM_ENC_STATUS),
  98	};
  99
 100	if (req_type >= ARRAY_SIZE(req_type_str) ||
 101	    !req_type_str[req_type])
 102		return "unknown";
 103
 104	return req_type_str[req_type];
 105}
 106
 107#undef DP_STR
 108#define DP_STR(x) [DP_NAK_ ## x] = #x
 109
 110static const char *drm_dp_mst_nak_reason_str(u8 nak_reason)
 111{
 112	static const char * const nak_reason_str[] = {
 113		DP_STR(WRITE_FAILURE),
 114		DP_STR(INVALID_READ),
 115		DP_STR(CRC_FAILURE),
 116		DP_STR(BAD_PARAM),
 117		DP_STR(DEFER),
 118		DP_STR(LINK_FAILURE),
 119		DP_STR(NO_RESOURCES),
 120		DP_STR(DPCD_FAIL),
 121		DP_STR(I2C_NAK),
 122		DP_STR(ALLOCATE_FAIL),
 123	};
 124
 125	if (nak_reason >= ARRAY_SIZE(nak_reason_str) ||
 126	    !nak_reason_str[nak_reason])
 127		return "unknown";
 128
 129	return nak_reason_str[nak_reason];
 130}
 131
 132#undef DP_STR
 133
 134/* sideband msg handling */
 135static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
 136{
 137	u8 bitmask = 0x80;
 138	u8 bitshift = 7;
 139	u8 array_index = 0;
 140	int number_of_bits = num_nibbles * 4;
 141	u8 remainder = 0;
 142
 143	while (number_of_bits != 0) {
 144		number_of_bits--;
 145		remainder <<= 1;
 146		remainder |= (data[array_index] & bitmask) >> bitshift;
 147		bitmask >>= 1;
 148		bitshift--;
 149		if (bitmask == 0) {
 150			bitmask = 0x80;
 151			bitshift = 7;
 152			array_index++;
 153		}
 154		if ((remainder & 0x10) == 0x10)
 155			remainder ^= 0x13;
 156	}
 157
 158	number_of_bits = 4;
 159	while (number_of_bits != 0) {
 160		number_of_bits--;
 161		remainder <<= 1;
 162		if ((remainder & 0x10) != 0)
 163			remainder ^= 0x13;
 164	}
 165
 166	return remainder;
 167}
 168
 169static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes)
 170{
 171	u8 bitmask = 0x80;
 172	u8 bitshift = 7;
 173	u8 array_index = 0;
 174	int number_of_bits = number_of_bytes * 8;
 175	u16 remainder = 0;
 176
 177	while (number_of_bits != 0) {
 178		number_of_bits--;
 179		remainder <<= 1;
 180		remainder |= (data[array_index] & bitmask) >> bitshift;
 181		bitmask >>= 1;
 182		bitshift--;
 183		if (bitmask == 0) {
 184			bitmask = 0x80;
 185			bitshift = 7;
 186			array_index++;
 187		}
 188		if ((remainder & 0x100) == 0x100)
 189			remainder ^= 0xd5;
 190	}
 191
 192	number_of_bits = 8;
 193	while (number_of_bits != 0) {
 194		number_of_bits--;
 195		remainder <<= 1;
 196		if ((remainder & 0x100) != 0)
 197			remainder ^= 0xd5;
 198	}
 199
 200	return remainder & 0xff;
 201}
 202static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr)
 203{
 204	u8 size = 3;
 205	size += (hdr->lct / 2);
 206	return size;
 207}
 208
 209static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
 210					   u8 *buf, int *len)
 211{
 212	int idx = 0;
 213	int i;
 214	u8 crc4;
 215	buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
 216	for (i = 0; i < (hdr->lct / 2); i++)
 217		buf[idx++] = hdr->rad[i];
 218	buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
 219		(hdr->msg_len & 0x3f);
 220	buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
 221
 222	crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
 223	buf[idx - 1] |= (crc4 & 0xf);
 224
 225	*len = idx;
 226}
 227
 228static bool drm_dp_decode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
 229					   u8 *buf, int buflen, u8 *hdrlen)
 230{
 231	u8 crc4;
 232	u8 len;
 233	int i;
 234	u8 idx;
 235	if (buf[0] == 0)
 236		return false;
 237	len = 3;
 238	len += ((buf[0] & 0xf0) >> 4) / 2;
 239	if (len > buflen)
 240		return false;
 241	crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
 242
 243	if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
 244		DRM_DEBUG_KMS("crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
 245		return false;
 246	}
 247
 248	hdr->lct = (buf[0] & 0xf0) >> 4;
 249	hdr->lcr = (buf[0] & 0xf);
 250	idx = 1;
 251	for (i = 0; i < (hdr->lct / 2); i++)
 252		hdr->rad[i] = buf[idx++];
 253	hdr->broadcast = (buf[idx] >> 7) & 0x1;
 254	hdr->path_msg = (buf[idx] >> 6) & 0x1;
 255	hdr->msg_len = buf[idx] & 0x3f;
 256	idx++;
 257	hdr->somt = (buf[idx] >> 7) & 0x1;
 258	hdr->eomt = (buf[idx] >> 6) & 0x1;
 259	hdr->seqno = (buf[idx] >> 4) & 0x1;
 260	idx++;
 261	*hdrlen = idx;
 262	return true;
 263}
 264
 265static void drm_dp_encode_sideband_req(struct drm_dp_sideband_msg_req_body *req,
 266				       struct drm_dp_sideband_msg_tx *raw)
 267{
 268	int idx = 0;
 269	int i;
 270	u8 *buf = raw->msg;
 271	buf[idx++] = req->req_type & 0x7f;
 272
 273	switch (req->req_type) {
 274	case DP_ENUM_PATH_RESOURCES:
 275		buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
 276		idx++;
 277		break;
 278	case DP_ALLOCATE_PAYLOAD:
 279		buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
 280			(req->u.allocate_payload.number_sdp_streams & 0xf);
 281		idx++;
 282		buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
 283		idx++;
 284		buf[idx] = (req->u.allocate_payload.pbn >> 8);
 285		idx++;
 286		buf[idx] = (req->u.allocate_payload.pbn & 0xff);
 287		idx++;
 288		for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
 289			buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) |
 290				(req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
 291			idx++;
 292		}
 293		if (req->u.allocate_payload.number_sdp_streams & 1) {
 294			i = req->u.allocate_payload.number_sdp_streams - 1;
 295			buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
 296			idx++;
 297		}
 298		break;
 299	case DP_QUERY_PAYLOAD:
 300		buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
 301		idx++;
 302		buf[idx] = (req->u.query_payload.vcpi & 0x7f);
 303		idx++;
 304		break;
 305	case DP_REMOTE_DPCD_READ:
 306		buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
 307		buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
 308		idx++;
 309		buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
 310		idx++;
 311		buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
 312		idx++;
 313		buf[idx] = (req->u.dpcd_read.num_bytes);
 314		idx++;
 315		break;
 316
 317	case DP_REMOTE_DPCD_WRITE:
 318		buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
 319		buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
 320		idx++;
 321		buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
 322		idx++;
 323		buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
 324		idx++;
 325		buf[idx] = (req->u.dpcd_write.num_bytes);
 326		idx++;
 327		memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
 328		idx += req->u.dpcd_write.num_bytes;
 329		break;
 330	case DP_REMOTE_I2C_READ:
 331		buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
 332		buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
 333		idx++;
 334		for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
 335			buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
 336			idx++;
 337			buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
 338			idx++;
 339			memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes);
 340			idx += req->u.i2c_read.transactions[i].num_bytes;
 341
 342			buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 5;
 343			buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf);
 344			idx++;
 345		}
 346		buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
 347		idx++;
 348		buf[idx] = (req->u.i2c_read.num_bytes_read);
 349		idx++;
 350		break;
 351
 352	case DP_REMOTE_I2C_WRITE:
 353		buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
 354		idx++;
 355		buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
 356		idx++;
 357		buf[idx] = (req->u.i2c_write.num_bytes);
 358		idx++;
 359		memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
 360		idx += req->u.i2c_write.num_bytes;
 361		break;
 362
 363	case DP_POWER_DOWN_PHY:
 364	case DP_POWER_UP_PHY:
 365		buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
 366		idx++;
 367		break;
 368	}
 369	raw->cur_len = idx;
 370}
 371
 372static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
 373{
 374	u8 crc4;
 375	crc4 = drm_dp_msg_data_crc4(msg, len);
 376	msg[len] = crc4;
 377}
 378
 379static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep,
 380					 struct drm_dp_sideband_msg_tx *raw)
 381{
 382	int idx = 0;
 383	u8 *buf = raw->msg;
 384
 385	buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
 386
 387	raw->cur_len = idx;
 388}
 389
 390/* this adds a chunk of msg to the builder to get the final msg */
 391static bool drm_dp_sideband_msg_build(struct drm_dp_sideband_msg_rx *msg,
 392				      u8 *replybuf, u8 replybuflen, bool hdr)
 393{
 394	int ret;
 395	u8 crc4;
 396
 397	if (hdr) {
 398		u8 hdrlen;
 399		struct drm_dp_sideband_msg_hdr recv_hdr;
 400		ret = drm_dp_decode_sideband_msg_hdr(&recv_hdr, replybuf, replybuflen, &hdrlen);
 401		if (ret == false) {
 402			print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16, 1, replybuf, replybuflen, false);
 403			return false;
 404		}
 405
 406		/*
 407		 * ignore out-of-order messages or messages that are part of a
 408		 * failed transaction
 409		 */
 410		if (!recv_hdr.somt && !msg->have_somt)
 411			return false;
 412
 413		/* get length contained in this portion */
 414		msg->curchunk_len = recv_hdr.msg_len;
 415		msg->curchunk_hdrlen = hdrlen;
 416
 417		/* we have already gotten an somt - don't bother parsing */
 418		if (recv_hdr.somt && msg->have_somt)
 419			return false;
 420
 421		if (recv_hdr.somt) {
 422			memcpy(&msg->initial_hdr, &recv_hdr, sizeof(struct drm_dp_sideband_msg_hdr));
 423			msg->have_somt = true;
 424		}
 425		if (recv_hdr.eomt)
 426			msg->have_eomt = true;
 427
 428		/* copy the bytes for the remainder of this header chunk */
 429		msg->curchunk_idx = min(msg->curchunk_len, (u8)(replybuflen - hdrlen));
 430		memcpy(&msg->chunk[0], replybuf + hdrlen, msg->curchunk_idx);
 431	} else {
 432		memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
 433		msg->curchunk_idx += replybuflen;
 434	}
 435
 436	if (msg->curchunk_idx >= msg->curchunk_len) {
 437		/* do CRC */
 438		crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
 439		/* copy chunk into bigger msg */
 440		memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
 441		msg->curlen += msg->curchunk_len - 1;
 442	}
 443	return true;
 444}
 445
 446static bool drm_dp_sideband_parse_link_address(struct drm_dp_sideband_msg_rx *raw,
 447					       struct drm_dp_sideband_msg_reply_body *repmsg)
 448{
 449	int idx = 1;
 450	int i;
 451	memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
 452	idx += 16;
 453	repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
 454	idx++;
 455	if (idx > raw->curlen)
 456		goto fail_len;
 457	for (i = 0; i < repmsg->u.link_addr.nports; i++) {
 458		if (raw->msg[idx] & 0x80)
 459			repmsg->u.link_addr.ports[i].input_port = 1;
 460
 461		repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7;
 462		repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
 463
 464		idx++;
 465		if (idx > raw->curlen)
 466			goto fail_len;
 467		repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
 468		repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
 469		if (repmsg->u.link_addr.ports[i].input_port == 0)
 470			repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
 471		idx++;
 472		if (idx > raw->curlen)
 473			goto fail_len;
 474		if (repmsg->u.link_addr.ports[i].input_port == 0) {
 475			repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
 476			idx++;
 477			if (idx > raw->curlen)
 478				goto fail_len;
 479			memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
 480			idx += 16;
 481			if (idx > raw->curlen)
 482				goto fail_len;
 483			repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf;
 484			repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf);
 485			idx++;
 486
 487		}
 488		if (idx > raw->curlen)
 489			goto fail_len;
 490	}
 491
 492	return true;
 493fail_len:
 494	DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 495	return false;
 496}
 497
 498static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw,
 499						   struct drm_dp_sideband_msg_reply_body *repmsg)
 500{
 501	int idx = 1;
 502	repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
 503	idx++;
 504	if (idx > raw->curlen)
 505		goto fail_len;
 506	repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
 507	idx++;
 508	if (idx > raw->curlen)
 509		goto fail_len;
 510
 511	memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes);
 512	return true;
 513fail_len:
 514	DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 515	return false;
 516}
 517
 518static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw,
 519						      struct drm_dp_sideband_msg_reply_body *repmsg)
 520{
 521	int idx = 1;
 522	repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
 523	idx++;
 524	if (idx > raw->curlen)
 525		goto fail_len;
 526	return true;
 527fail_len:
 528	DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
 529	return false;
 530}
 531
 532static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw,
 533						      struct drm_dp_sideband_msg_reply_body *repmsg)
 534{
 535	int idx = 1;
 536
 537	repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
 538	idx++;
 539	if (idx > raw->curlen)
 540		goto fail_len;
 541	repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
 542	idx++;
 543	/* TODO check */
 544	memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes);
 545	return true;
 546fail_len:
 547	DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen);
 548	return false;
 549}
 550
 551static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw,
 552							  struct drm_dp_sideband_msg_reply_body *repmsg)
 553{
 554	int idx = 1;
 555	repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
 556	idx++;
 557	if (idx > raw->curlen)
 558		goto fail_len;
 559	repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 560	idx += 2;
 561	if (idx > raw->curlen)
 562		goto fail_len;
 563	repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 564	idx += 2;
 565	if (idx > raw->curlen)
 566		goto fail_len;
 567	return true;
 568fail_len:
 569	DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen);
 570	return false;
 571}
 572
 573static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 574							  struct drm_dp_sideband_msg_reply_body *repmsg)
 575{
 576	int idx = 1;
 577	repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 578	idx++;
 579	if (idx > raw->curlen)
 580		goto fail_len;
 581	repmsg->u.allocate_payload.vcpi = raw->msg[idx];
 582	idx++;
 583	if (idx > raw->curlen)
 584		goto fail_len;
 585	repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 586	idx += 2;
 587	if (idx > raw->curlen)
 588		goto fail_len;
 589	return true;
 590fail_len:
 591	DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen);
 592	return false;
 593}
 594
 595static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 596						    struct drm_dp_sideband_msg_reply_body *repmsg)
 597{
 598	int idx = 1;
 599	repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 600	idx++;
 601	if (idx > raw->curlen)
 602		goto fail_len;
 603	repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
 604	idx += 2;
 605	if (idx > raw->curlen)
 606		goto fail_len;
 607	return true;
 608fail_len:
 609	DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen);
 610	return false;
 611}
 612
 613static bool drm_dp_sideband_parse_power_updown_phy_ack(struct drm_dp_sideband_msg_rx *raw,
 614						       struct drm_dp_sideband_msg_reply_body *repmsg)
 615{
 616	int idx = 1;
 617
 618	repmsg->u.port_number.port_number = (raw->msg[idx] >> 4) & 0xf;
 619	idx++;
 620	if (idx > raw->curlen) {
 621		DRM_DEBUG_KMS("power up/down phy parse length fail %d %d\n",
 622			      idx, raw->curlen);
 623		return false;
 624	}
 625	return true;
 626}
 627
 628static bool drm_dp_sideband_parse_reply(struct drm_dp_sideband_msg_rx *raw,
 629					struct drm_dp_sideband_msg_reply_body *msg)
 630{
 631	memset(msg, 0, sizeof(*msg));
 632	msg->reply_type = (raw->msg[0] & 0x80) >> 7;
 633	msg->req_type = (raw->msg[0] & 0x7f);
 634
 635	if (msg->reply_type == DP_SIDEBAND_REPLY_NAK) {
 636		memcpy(msg->u.nak.guid, &raw->msg[1], 16);
 637		msg->u.nak.reason = raw->msg[17];
 638		msg->u.nak.nak_data = raw->msg[18];
 639		return false;
 640	}
 641
 642	switch (msg->req_type) {
 643	case DP_LINK_ADDRESS:
 644		return drm_dp_sideband_parse_link_address(raw, msg);
 645	case DP_QUERY_PAYLOAD:
 646		return drm_dp_sideband_parse_query_payload_ack(raw, msg);
 647	case DP_REMOTE_DPCD_READ:
 648		return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
 649	case DP_REMOTE_DPCD_WRITE:
 650		return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
 651	case DP_REMOTE_I2C_READ:
 652		return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
 653	case DP_ENUM_PATH_RESOURCES:
 654		return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
 655	case DP_ALLOCATE_PAYLOAD:
 656		return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
 657	case DP_POWER_DOWN_PHY:
 658	case DP_POWER_UP_PHY:
 659		return drm_dp_sideband_parse_power_updown_phy_ack(raw, msg);
 660	default:
 661		DRM_ERROR("Got unknown reply 0x%02x (%s)\n", msg->req_type,
 662			  drm_dp_mst_req_type_str(msg->req_type));
 663		return false;
 664	}
 665}
 666
 667static bool drm_dp_sideband_parse_connection_status_notify(struct drm_dp_sideband_msg_rx *raw,
 668							   struct drm_dp_sideband_msg_req_body *msg)
 669{
 670	int idx = 1;
 671
 672	msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
 673	idx++;
 674	if (idx > raw->curlen)
 675		goto fail_len;
 676
 677	memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
 678	idx += 16;
 679	if (idx > raw->curlen)
 680		goto fail_len;
 681
 682	msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
 683	msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
 684	msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
 685	msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
 686	msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
 687	idx++;
 688	return true;
 689fail_len:
 690	DRM_DEBUG_KMS("connection status reply parse length fail %d %d\n", idx, raw->curlen);
 691	return false;
 692}
 693
 694static bool drm_dp_sideband_parse_resource_status_notify(struct drm_dp_sideband_msg_rx *raw,
 695							   struct drm_dp_sideband_msg_req_body *msg)
 696{
 697	int idx = 1;
 698
 699	msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
 700	idx++;
 701	if (idx > raw->curlen)
 702		goto fail_len;
 703
 704	memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
 705	idx += 16;
 706	if (idx > raw->curlen)
 707		goto fail_len;
 708
 709	msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
 710	idx++;
 711	return true;
 712fail_len:
 713	DRM_DEBUG_KMS("resource status reply parse length fail %d %d\n", idx, raw->curlen);
 714	return false;
 715}
 716
 717static bool drm_dp_sideband_parse_req(struct drm_dp_sideband_msg_rx *raw,
 718				      struct drm_dp_sideband_msg_req_body *msg)
 719{
 720	memset(msg, 0, sizeof(*msg));
 721	msg->req_type = (raw->msg[0] & 0x7f);
 722
 723	switch (msg->req_type) {
 724	case DP_CONNECTION_STATUS_NOTIFY:
 725		return drm_dp_sideband_parse_connection_status_notify(raw, msg);
 726	case DP_RESOURCE_STATUS_NOTIFY:
 727		return drm_dp_sideband_parse_resource_status_notify(raw, msg);
 728	default:
 729		DRM_ERROR("Got unknown request 0x%02x (%s)\n", msg->req_type,
 730			  drm_dp_mst_req_type_str(msg->req_type));
 731		return false;
 732	}
 733}
 734
 735static int build_dpcd_write(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
 736{
 737	struct drm_dp_sideband_msg_req_body req;
 738
 739	req.req_type = DP_REMOTE_DPCD_WRITE;
 740	req.u.dpcd_write.port_number = port_num;
 741	req.u.dpcd_write.dpcd_address = offset;
 742	req.u.dpcd_write.num_bytes = num_bytes;
 743	req.u.dpcd_write.bytes = bytes;
 744	drm_dp_encode_sideband_req(&req, msg);
 745
 746	return 0;
 747}
 748
 749static int build_link_address(struct drm_dp_sideband_msg_tx *msg)
 750{
 751	struct drm_dp_sideband_msg_req_body req;
 752
 753	req.req_type = DP_LINK_ADDRESS;
 754	drm_dp_encode_sideband_req(&req, msg);
 755	return 0;
 756}
 757
 758static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg, int port_num)
 759{
 760	struct drm_dp_sideband_msg_req_body req;
 761
 762	req.req_type = DP_ENUM_PATH_RESOURCES;
 763	req.u.port_num.port_number = port_num;
 764	drm_dp_encode_sideband_req(&req, msg);
 765	msg->path_msg = true;
 766	return 0;
 767}
 768
 769static int build_allocate_payload(struct drm_dp_sideband_msg_tx *msg, int port_num,
 770				  u8 vcpi, uint16_t pbn,
 771				  u8 number_sdp_streams,
 772				  u8 *sdp_stream_sink)
 773{
 774	struct drm_dp_sideband_msg_req_body req;
 775	memset(&req, 0, sizeof(req));
 776	req.req_type = DP_ALLOCATE_PAYLOAD;
 777	req.u.allocate_payload.port_number = port_num;
 778	req.u.allocate_payload.vcpi = vcpi;
 779	req.u.allocate_payload.pbn = pbn;
 780	req.u.allocate_payload.number_sdp_streams = number_sdp_streams;
 781	memcpy(req.u.allocate_payload.sdp_stream_sink, sdp_stream_sink,
 782		   number_sdp_streams);
 783	drm_dp_encode_sideband_req(&req, msg);
 784	msg->path_msg = true;
 785	return 0;
 786}
 787
 788static int build_power_updown_phy(struct drm_dp_sideband_msg_tx *msg,
 789				  int port_num, bool power_up)
 790{
 791	struct drm_dp_sideband_msg_req_body req;
 792
 793	if (power_up)
 794		req.req_type = DP_POWER_UP_PHY;
 795	else
 796		req.req_type = DP_POWER_DOWN_PHY;
 797
 798	req.u.port_num.port_number = port_num;
 799	drm_dp_encode_sideband_req(&req, msg);
 800	msg->path_msg = true;
 801	return 0;
 802}
 803
 804static int drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr *mgr,
 805					struct drm_dp_vcpi *vcpi)
 806{
 807	int ret, vcpi_ret;
 808
 809	mutex_lock(&mgr->payload_lock);
 810	ret = find_first_zero_bit(&mgr->payload_mask, mgr->max_payloads + 1);
 811	if (ret > mgr->max_payloads) {
 812		ret = -EINVAL;
 813		DRM_DEBUG_KMS("out of payload ids %d\n", ret);
 814		goto out_unlock;
 815	}
 816
 817	vcpi_ret = find_first_zero_bit(&mgr->vcpi_mask, mgr->max_payloads + 1);
 818	if (vcpi_ret > mgr->max_payloads) {
 819		ret = -EINVAL;
 820		DRM_DEBUG_KMS("out of vcpi ids %d\n", ret);
 821		goto out_unlock;
 822	}
 823
 824	set_bit(ret, &mgr->payload_mask);
 825	set_bit(vcpi_ret, &mgr->vcpi_mask);
 826	vcpi->vcpi = vcpi_ret + 1;
 827	mgr->proposed_vcpis[ret - 1] = vcpi;
 828out_unlock:
 829	mutex_unlock(&mgr->payload_lock);
 830	return ret;
 831}
 832
 833static void drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr *mgr,
 834				      int vcpi)
 835{
 836	int i;
 837	if (vcpi == 0)
 838		return;
 839
 840	mutex_lock(&mgr->payload_lock);
 841	DRM_DEBUG_KMS("putting payload %d\n", vcpi);
 842	clear_bit(vcpi - 1, &mgr->vcpi_mask);
 843
 844	for (i = 0; i < mgr->max_payloads; i++) {
 845		if (mgr->proposed_vcpis[i])
 846			if (mgr->proposed_vcpis[i]->vcpi == vcpi) {
 847				mgr->proposed_vcpis[i] = NULL;
 848				clear_bit(i + 1, &mgr->payload_mask);
 849			}
 850	}
 851	mutex_unlock(&mgr->payload_lock);
 852}
 853
 854static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
 855			      struct drm_dp_sideband_msg_tx *txmsg)
 856{
 857	unsigned int state;
 858
 859	/*
 860	 * All updates to txmsg->state are protected by mgr->qlock, and the two
 861	 * cases we check here are terminal states. For those the barriers
 862	 * provided by the wake_up/wait_event pair are enough.
 863	 */
 864	state = READ_ONCE(txmsg->state);
 865	return (state == DRM_DP_SIDEBAND_TX_RX ||
 866		state == DRM_DP_SIDEBAND_TX_TIMEOUT);
 867}
 868
 869static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
 870				    struct drm_dp_sideband_msg_tx *txmsg)
 871{
 872	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
 873	int ret;
 874
 875	ret = wait_event_timeout(mgr->tx_waitq,
 876				 check_txmsg_state(mgr, txmsg),
 877				 (4 * HZ));
 878	mutex_lock(&mstb->mgr->qlock);
 879	if (ret > 0) {
 880		if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
 881			ret = -EIO;
 882			goto out;
 883		}
 884	} else {
 885		DRM_DEBUG_KMS("timedout msg send %p %d %d\n", txmsg, txmsg->state, txmsg->seqno);
 886
 887		/* dump some state */
 888		ret = -EIO;
 889
 890		/* remove from q */
 891		if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
 892		    txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND) {
 893			list_del(&txmsg->next);
 894		}
 895
 896		if (txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
 897		    txmsg->state == DRM_DP_SIDEBAND_TX_SENT) {
 898			mstb->tx_slots[txmsg->seqno] = NULL;
 899		}
 900	}
 901out:
 902	mutex_unlock(&mgr->qlock);
 903
 904	return ret;
 905}
 906
 907static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
 908{
 909	struct drm_dp_mst_branch *mstb;
 910
 911	mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
 912	if (!mstb)
 913		return NULL;
 914
 915	mstb->lct = lct;
 916	if (lct > 1)
 917		memcpy(mstb->rad, rad, lct / 2);
 918	INIT_LIST_HEAD(&mstb->ports);
 919	kref_init(&mstb->topology_kref);
 920	kref_init(&mstb->malloc_kref);
 921	return mstb;
 922}
 923
 
 
 924static void drm_dp_free_mst_branch_device(struct kref *kref)
 925{
 926	struct drm_dp_mst_branch *mstb =
 927		container_of(kref, struct drm_dp_mst_branch, malloc_kref);
 928
 929	if (mstb->port_parent)
 930		drm_dp_mst_put_port_malloc(mstb->port_parent);
 931
 932	kfree(mstb);
 933}
 934
 935/**
 936 * DOC: Branch device and port refcounting
 937 *
 938 * Topology refcount overview
 939 * ~~~~~~~~~~~~~~~~~~~~~~~~~~
 940 *
 941 * The refcounting schemes for &struct drm_dp_mst_branch and &struct
 942 * drm_dp_mst_port are somewhat unusual. Both ports and branch devices have
 943 * two different kinds of refcounts: topology refcounts, and malloc refcounts.
 944 *
 945 * Topology refcounts are not exposed to drivers, and are handled internally
 946 * by the DP MST helpers. The helpers use them in order to prevent the
 947 * in-memory topology state from being changed in the middle of critical
 948 * operations like changing the internal state of payload allocations. This
 949 * means each branch and port will be considered to be connected to the rest
 950 * of the topology until its topology refcount reaches zero. Additionally,
 951 * for ports this means that their associated &struct drm_connector will stay
 952 * registered with userspace until the port's refcount reaches 0.
 953 *
 954 * Malloc refcount overview
 955 * ~~~~~~~~~~~~~~~~~~~~~~~~
 956 *
 957 * Malloc references are used to keep a &struct drm_dp_mst_port or &struct
 958 * drm_dp_mst_branch allocated even after all of its topology references have
 959 * been dropped, so that the driver or MST helpers can safely access each
 960 * branch's last known state before it was disconnected from the topology.
 961 * When the malloc refcount of a port or branch reaches 0, the memory
 962 * allocation containing the &struct drm_dp_mst_branch or &struct
 963 * drm_dp_mst_port respectively will be freed.
 964 *
 965 * For &struct drm_dp_mst_branch, malloc refcounts are not currently exposed
 966 * to drivers. As of writing this documentation, there are no drivers that
 967 * have a usecase for accessing &struct drm_dp_mst_branch outside of the MST
 968 * helpers. Exposing this API to drivers in a race-free manner would take more
 969 * tweaking of the refcounting scheme, however patches are welcome provided
 970 * there is a legitimate driver usecase for this.
 971 *
 972 * Refcount relationships in a topology
 973 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 974 *
 975 * Let's take a look at why the relationship between topology and malloc
 976 * refcounts is designed the way it is.
 977 *
 978 * .. kernel-figure:: dp-mst/topology-figure-1.dot
 979 *
 980 *    An example of topology and malloc refs in a DP MST topology with two
 981 *    active payloads. Topology refcount increments are indicated by solid
 982 *    lines, and malloc refcount increments are indicated by dashed lines.
 983 *    Each starts from the branch which incremented the refcount, and ends at
 984 *    the branch to which the refcount belongs to, i.e. the arrow points the
 985 *    same way as the C pointers used to reference a structure.
 986 *
 987 * As you can see in the above figure, every branch increments the topology
 988 * refcount of its children, and increments the malloc refcount of its
 989 * parent. Additionally, every payload increments the malloc refcount of its
 990 * assigned port by 1.
 991 *
 992 * So, what would happen if MSTB #3 from the above figure was unplugged from
 993 * the system, but the driver hadn't yet removed payload #2 from port #3? The
 994 * topology would start to look like the figure below.
 995 *
 996 * .. kernel-figure:: dp-mst/topology-figure-2.dot
 997 *
 998 *    Ports and branch devices which have been released from memory are
 999 *    colored grey, and references which have been removed are colored red.
1000 *
1001 * Whenever a port or branch device's topology refcount reaches zero, it will
1002 * decrement the topology refcounts of all its children, the malloc refcount
1003 * of its parent, and finally its own malloc refcount. For MSTB #4 and port
1004 * #4, this means they both have been disconnected from the topology and freed
1005 * from memory. But, because payload #2 is still holding a reference to port
1006 * #3, port #3 is removed from the topology but its &struct drm_dp_mst_port
1007 * is still accessible from memory. This also means port #3 has not yet
1008 * decremented the malloc refcount of MSTB #3, so its &struct
1009 * drm_dp_mst_branch will also stay allocated in memory until port #3's
1010 * malloc refcount reaches 0.
1011 *
1012 * This relationship is necessary because in order to release payload #2, we
1013 * need to be able to figure out the last relative of port #3 that's still
1014 * connected to the topology. In this case, we would travel up the topology as
1015 * shown below.
1016 *
1017 * .. kernel-figure:: dp-mst/topology-figure-3.dot
1018 *
1019 * And finally, remove payload #2 by communicating with port #2 through
1020 * sideband transactions.
1021 */
1022
1023/**
1024 * drm_dp_mst_get_mstb_malloc() - Increment the malloc refcount of a branch
1025 * device
1026 * @mstb: The &struct drm_dp_mst_branch to increment the malloc refcount of
1027 *
1028 * Increments &drm_dp_mst_branch.malloc_kref. When
1029 * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1030 * will be released and @mstb may no longer be used.
1031 *
1032 * See also: drm_dp_mst_put_mstb_malloc()
1033 */
1034static void
1035drm_dp_mst_get_mstb_malloc(struct drm_dp_mst_branch *mstb)
1036{
1037	kref_get(&mstb->malloc_kref);
1038	DRM_DEBUG("mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref));
1039}
1040
1041/**
1042 * drm_dp_mst_put_mstb_malloc() - Decrement the malloc refcount of a branch
1043 * device
1044 * @mstb: The &struct drm_dp_mst_branch to decrement the malloc refcount of
1045 *
1046 * Decrements &drm_dp_mst_branch.malloc_kref. When
1047 * &drm_dp_mst_branch.malloc_kref reaches 0, the memory allocation for @mstb
1048 * will be released and @mstb may no longer be used.
1049 *
1050 * See also: drm_dp_mst_get_mstb_malloc()
1051 */
1052static void
1053drm_dp_mst_put_mstb_malloc(struct drm_dp_mst_branch *mstb)
1054{
1055	DRM_DEBUG("mstb %p (%d)\n", mstb, kref_read(&mstb->malloc_kref) - 1);
1056	kref_put(&mstb->malloc_kref, drm_dp_free_mst_branch_device);
1057}
1058
1059static void drm_dp_free_mst_port(struct kref *kref)
1060{
1061	struct drm_dp_mst_port *port =
1062		container_of(kref, struct drm_dp_mst_port, malloc_kref);
1063
1064	drm_dp_mst_put_mstb_malloc(port->parent);
1065	kfree(port);
1066}
1067
1068/**
1069 * drm_dp_mst_get_port_malloc() - Increment the malloc refcount of an MST port
1070 * @port: The &struct drm_dp_mst_port to increment the malloc refcount of
1071 *
1072 * Increments &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1073 * reaches 0, the memory allocation for @port will be released and @port may
1074 * no longer be used.
1075 *
1076 * Because @port could potentially be freed at any time by the DP MST helpers
1077 * if &drm_dp_mst_port.malloc_kref reaches 0, including during a call to this
1078 * function, drivers that which to make use of &struct drm_dp_mst_port should
1079 * ensure that they grab at least one main malloc reference to their MST ports
1080 * in &drm_dp_mst_topology_cbs.add_connector. This callback is called before
1081 * there is any chance for &drm_dp_mst_port.malloc_kref to reach 0.
1082 *
1083 * See also: drm_dp_mst_put_port_malloc()
1084 */
1085void
1086drm_dp_mst_get_port_malloc(struct drm_dp_mst_port *port)
1087{
1088	kref_get(&port->malloc_kref);
1089	DRM_DEBUG("port %p (%d)\n", port, kref_read(&port->malloc_kref));
1090}
1091EXPORT_SYMBOL(drm_dp_mst_get_port_malloc);
1092
1093/**
1094 * drm_dp_mst_put_port_malloc() - Decrement the malloc refcount of an MST port
1095 * @port: The &struct drm_dp_mst_port to decrement the malloc refcount of
1096 *
1097 * Decrements &drm_dp_mst_port.malloc_kref. When &drm_dp_mst_port.malloc_kref
1098 * reaches 0, the memory allocation for @port will be released and @port may
1099 * no longer be used.
1100 *
1101 * See also: drm_dp_mst_get_port_malloc()
1102 */
1103void
1104drm_dp_mst_put_port_malloc(struct drm_dp_mst_port *port)
1105{
1106	DRM_DEBUG("port %p (%d)\n", port, kref_read(&port->malloc_kref) - 1);
1107	kref_put(&port->malloc_kref, drm_dp_free_mst_port);
1108}
1109EXPORT_SYMBOL(drm_dp_mst_put_port_malloc);
1110
1111static void drm_dp_destroy_mst_branch_device(struct kref *kref)
1112{
1113	struct drm_dp_mst_branch *mstb =
1114		container_of(kref, struct drm_dp_mst_branch, topology_kref);
1115	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
1116	struct drm_dp_mst_port *port, *tmp;
1117	bool wake_tx = false;
1118
1119	mutex_lock(&mgr->lock);
 
 
 
 
 
 
 
 
 
 
 
 
 
1120	list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
1121		list_del(&port->next);
1122		drm_dp_mst_topology_put_port(port);
1123	}
1124	mutex_unlock(&mgr->lock);
1125
1126	/* drop any tx slots msg */
1127	mutex_lock(&mstb->mgr->qlock);
1128	if (mstb->tx_slots[0]) {
1129		mstb->tx_slots[0]->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
1130		mstb->tx_slots[0] = NULL;
1131		wake_tx = true;
1132	}
1133	if (mstb->tx_slots[1]) {
1134		mstb->tx_slots[1]->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
1135		mstb->tx_slots[1] = NULL;
1136		wake_tx = true;
1137	}
1138	mutex_unlock(&mstb->mgr->qlock);
1139
1140	if (wake_tx)
1141		wake_up_all(&mstb->mgr->tx_waitq);
1142
1143	drm_dp_mst_put_mstb_malloc(mstb);
1144}
1145
1146/**
1147 * drm_dp_mst_topology_try_get_mstb() - Increment the topology refcount of a
1148 * branch device unless it's zero
1149 * @mstb: &struct drm_dp_mst_branch to increment the topology refcount of
1150 *
1151 * Attempts to grab a topology reference to @mstb, if it hasn't yet been
1152 * removed from the topology (e.g. &drm_dp_mst_branch.topology_kref has
1153 * reached 0). Holding a topology reference implies that a malloc reference
1154 * will be held to @mstb as long as the user holds the topology reference.
1155 *
1156 * Care should be taken to ensure that the user has at least one malloc
1157 * reference to @mstb. If you already have a topology reference to @mstb, you
1158 * should use drm_dp_mst_topology_get_mstb() instead.
1159 *
1160 * See also:
1161 * drm_dp_mst_topology_get_mstb()
1162 * drm_dp_mst_topology_put_mstb()
1163 *
1164 * Returns:
1165 * * 1: A topology reference was grabbed successfully
1166 * * 0: @port is no longer in the topology, no reference was grabbed
1167 */
1168static int __must_check
1169drm_dp_mst_topology_try_get_mstb(struct drm_dp_mst_branch *mstb)
1170{
1171	int ret = kref_get_unless_zero(&mstb->topology_kref);
1172
1173	if (ret)
1174		DRM_DEBUG("mstb %p (%d)\n", mstb,
1175			  kref_read(&mstb->topology_kref));
1176
1177	return ret;
1178}
1179
1180/**
1181 * drm_dp_mst_topology_get_mstb() - Increment the topology refcount of a
1182 * branch device
1183 * @mstb: The &struct drm_dp_mst_branch to increment the topology refcount of
1184 *
1185 * Increments &drm_dp_mst_branch.topology_refcount without checking whether or
1186 * not it's already reached 0. This is only valid to use in scenarios where
1187 * you are already guaranteed to have at least one active topology reference
1188 * to @mstb. Otherwise, drm_dp_mst_topology_try_get_mstb() must be used.
1189 *
1190 * See also:
1191 * drm_dp_mst_topology_try_get_mstb()
1192 * drm_dp_mst_topology_put_mstb()
1193 */
1194static void drm_dp_mst_topology_get_mstb(struct drm_dp_mst_branch *mstb)
1195{
1196	WARN_ON(kref_read(&mstb->topology_kref) == 0);
1197	kref_get(&mstb->topology_kref);
1198	DRM_DEBUG("mstb %p (%d)\n", mstb, kref_read(&mstb->topology_kref));
1199}
1200
1201/**
1202 * drm_dp_mst_topology_put_mstb() - release a topology reference to a branch
1203 * device
1204 * @mstb: The &struct drm_dp_mst_branch to release the topology reference from
1205 *
1206 * Releases a topology reference from @mstb by decrementing
1207 * &drm_dp_mst_branch.topology_kref.
1208 *
1209 * See also:
1210 * drm_dp_mst_topology_try_get_mstb()
1211 * drm_dp_mst_topology_get_mstb()
1212 */
1213static void
1214drm_dp_mst_topology_put_mstb(struct drm_dp_mst_branch *mstb)
1215{
1216	DRM_DEBUG("mstb %p (%d)\n",
1217		  mstb, kref_read(&mstb->topology_kref) - 1);
1218	kref_put(&mstb->topology_kref, drm_dp_destroy_mst_branch_device);
1219}
1220
1221static void drm_dp_port_teardown_pdt(struct drm_dp_mst_port *port, int old_pdt)
1222{
1223	struct drm_dp_mst_branch *mstb;
1224
1225	switch (old_pdt) {
1226	case DP_PEER_DEVICE_DP_LEGACY_CONV:
1227	case DP_PEER_DEVICE_SST_SINK:
1228		/* remove i2c over sideband */
1229		drm_dp_mst_unregister_i2c_bus(&port->aux);
1230		break;
1231	case DP_PEER_DEVICE_MST_BRANCHING:
1232		mstb = port->mstb;
1233		port->mstb = NULL;
1234		drm_dp_mst_topology_put_mstb(mstb);
1235		break;
1236	}
1237}
1238
1239static void drm_dp_destroy_port(struct kref *kref)
1240{
1241	struct drm_dp_mst_port *port =
1242		container_of(kref, struct drm_dp_mst_port, topology_kref);
1243	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
1244
1245	if (!port->input) {
 
 
1246		kfree(port->cached_edid);
1247
1248		/*
1249		 * The only time we don't have a connector
1250		 * on an output port is if the connector init
1251		 * fails.
1252		 */
1253		if (port->connector) {
1254			/* we can't destroy the connector here, as
1255			 * we might be holding the mode_config.mutex
1256			 * from an EDID retrieval */
1257
1258			mutex_lock(&mgr->destroy_connector_lock);
 
1259			list_add(&port->next, &mgr->destroy_connector_list);
1260			mutex_unlock(&mgr->destroy_connector_lock);
1261			schedule_work(&mgr->destroy_connector_work);
1262			return;
1263		}
1264		/* no need to clean up vcpi
1265		 * as if we have no connector we never setup a vcpi */
1266		drm_dp_port_teardown_pdt(port, port->pdt);
1267		port->pdt = DP_PEER_DEVICE_NONE;
1268	}
1269	drm_dp_mst_put_port_malloc(port);
1270}
1271
1272/**
1273 * drm_dp_mst_topology_try_get_port() - Increment the topology refcount of a
1274 * port unless it's zero
1275 * @port: &struct drm_dp_mst_port to increment the topology refcount of
1276 *
1277 * Attempts to grab a topology reference to @port, if it hasn't yet been
1278 * removed from the topology (e.g. &drm_dp_mst_port.topology_kref has reached
1279 * 0). Holding a topology reference implies that a malloc reference will be
1280 * held to @port as long as the user holds the topology reference.
1281 *
1282 * Care should be taken to ensure that the user has at least one malloc
1283 * reference to @port. If you already have a topology reference to @port, you
1284 * should use drm_dp_mst_topology_get_port() instead.
1285 *
1286 * See also:
1287 * drm_dp_mst_topology_get_port()
1288 * drm_dp_mst_topology_put_port()
1289 *
1290 * Returns:
1291 * * 1: A topology reference was grabbed successfully
1292 * * 0: @port is no longer in the topology, no reference was grabbed
1293 */
1294static int __must_check
1295drm_dp_mst_topology_try_get_port(struct drm_dp_mst_port *port)
1296{
1297	int ret = kref_get_unless_zero(&port->topology_kref);
1298
1299	if (ret)
1300		DRM_DEBUG("port %p (%d)\n", port,
1301			  kref_read(&port->topology_kref));
1302
1303	return ret;
1304}
1305
1306/**
1307 * drm_dp_mst_topology_get_port() - Increment the topology refcount of a port
1308 * @port: The &struct drm_dp_mst_port to increment the topology refcount of
1309 *
1310 * Increments &drm_dp_mst_port.topology_refcount without checking whether or
1311 * not it's already reached 0. This is only valid to use in scenarios where
1312 * you are already guaranteed to have at least one active topology reference
1313 * to @port. Otherwise, drm_dp_mst_topology_try_get_port() must be used.
1314 *
1315 * See also:
1316 * drm_dp_mst_topology_try_get_port()
1317 * drm_dp_mst_topology_put_port()
1318 */
1319static void drm_dp_mst_topology_get_port(struct drm_dp_mst_port *port)
1320{
1321	WARN_ON(kref_read(&port->topology_kref) == 0);
1322	kref_get(&port->topology_kref);
1323	DRM_DEBUG("port %p (%d)\n", port, kref_read(&port->topology_kref));
1324}
1325
1326/**
1327 * drm_dp_mst_topology_put_port() - release a topology reference to a port
1328 * @port: The &struct drm_dp_mst_port to release the topology reference from
1329 *
1330 * Releases a topology reference from @port by decrementing
1331 * &drm_dp_mst_port.topology_kref.
1332 *
1333 * See also:
1334 * drm_dp_mst_topology_try_get_port()
1335 * drm_dp_mst_topology_get_port()
1336 */
1337static void drm_dp_mst_topology_put_port(struct drm_dp_mst_port *port)
1338{
1339	DRM_DEBUG("port %p (%d)\n",
1340		  port, kref_read(&port->topology_kref) - 1);
1341	kref_put(&port->topology_kref, drm_dp_destroy_port);
1342}
1343
1344static struct drm_dp_mst_branch *
1345drm_dp_mst_topology_get_mstb_validated_locked(struct drm_dp_mst_branch *mstb,
1346					      struct drm_dp_mst_branch *to_find)
1347{
1348	struct drm_dp_mst_port *port;
1349	struct drm_dp_mst_branch *rmstb;
1350
1351	if (to_find == mstb)
1352		return mstb;
1353
1354	list_for_each_entry(port, &mstb->ports, next) {
1355		if (port->mstb) {
1356			rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1357			    port->mstb, to_find);
1358			if (rmstb)
1359				return rmstb;
1360		}
1361	}
1362	return NULL;
1363}
1364
1365static struct drm_dp_mst_branch *
1366drm_dp_mst_topology_get_mstb_validated(struct drm_dp_mst_topology_mgr *mgr,
1367				       struct drm_dp_mst_branch *mstb)
1368{
1369	struct drm_dp_mst_branch *rmstb = NULL;
1370
1371	mutex_lock(&mgr->lock);
1372	if (mgr->mst_primary) {
1373		rmstb = drm_dp_mst_topology_get_mstb_validated_locked(
1374		    mgr->mst_primary, mstb);
1375
1376		if (rmstb && !drm_dp_mst_topology_try_get_mstb(rmstb))
1377			rmstb = NULL;
1378	}
1379	mutex_unlock(&mgr->lock);
1380	return rmstb;
1381}
1382
1383static struct drm_dp_mst_port *
1384drm_dp_mst_topology_get_port_validated_locked(struct drm_dp_mst_branch *mstb,
1385					      struct drm_dp_mst_port *to_find)
1386{
1387	struct drm_dp_mst_port *port, *mport;
1388
1389	list_for_each_entry(port, &mstb->ports, next) {
1390		if (port == to_find)
 
1391			return port;
1392
1393		if (port->mstb) {
1394			mport = drm_dp_mst_topology_get_port_validated_locked(
1395			    port->mstb, to_find);
1396			if (mport)
1397				return mport;
1398		}
1399	}
1400	return NULL;
1401}
1402
1403static struct drm_dp_mst_port *
1404drm_dp_mst_topology_get_port_validated(struct drm_dp_mst_topology_mgr *mgr,
1405				       struct drm_dp_mst_port *port)
1406{
1407	struct drm_dp_mst_port *rport = NULL;
1408
1409	mutex_lock(&mgr->lock);
1410	if (mgr->mst_primary) {
1411		rport = drm_dp_mst_topology_get_port_validated_locked(
1412		    mgr->mst_primary, port);
1413
1414		if (rport && !drm_dp_mst_topology_try_get_port(rport))
1415			rport = NULL;
1416	}
1417	mutex_unlock(&mgr->lock);
1418	return rport;
1419}
1420
1421static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
1422{
1423	struct drm_dp_mst_port *port;
1424	int ret;
1425
1426	list_for_each_entry(port, &mstb->ports, next) {
1427		if (port->port_num == port_num) {
1428			ret = drm_dp_mst_topology_try_get_port(port);
1429			return ret ? port : NULL;
1430		}
1431	}
1432
1433	return NULL;
1434}
1435
1436/*
1437 * calculate a new RAD for this MST branch device
1438 * if parent has an LCT of 2 then it has 1 nibble of RAD,
1439 * if parent has an LCT of 3 then it has 2 nibbles of RAD,
1440 */
1441static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
1442				 u8 *rad)
1443{
1444	int parent_lct = port->parent->lct;
1445	int shift = 4;
1446	int idx = (parent_lct - 1) / 2;
1447	if (parent_lct > 1) {
1448		memcpy(rad, port->parent->rad, idx + 1);
1449		shift = (parent_lct % 2) ? 4 : 0;
1450	} else
1451		rad[0] = 0;
1452
1453	rad[idx] |= port->port_num << shift;
1454	return parent_lct + 1;
1455}
1456
1457/*
1458 * return sends link address for new mstb
1459 */
1460static bool drm_dp_port_setup_pdt(struct drm_dp_mst_port *port)
1461{
1462	int ret;
1463	u8 rad[6], lct;
1464	bool send_link = false;
1465	switch (port->pdt) {
1466	case DP_PEER_DEVICE_DP_LEGACY_CONV:
1467	case DP_PEER_DEVICE_SST_SINK:
1468		/* add i2c over sideband */
1469		ret = drm_dp_mst_register_i2c_bus(&port->aux);
1470		break;
1471	case DP_PEER_DEVICE_MST_BRANCHING:
1472		lct = drm_dp_calculate_rad(port, rad);
1473
1474		port->mstb = drm_dp_add_mst_branch_device(lct, rad);
1475		if (port->mstb) {
1476			port->mstb->mgr = port->mgr;
1477			port->mstb->port_parent = port;
1478			/*
1479			 * Make sure this port's memory allocation stays
1480			 * around until its child MSTB releases it
1481			 */
1482			drm_dp_mst_get_port_malloc(port);
1483
1484			send_link = true;
1485		}
1486		break;
1487	}
1488	return send_link;
1489}
1490
1491/**
1492 * drm_dp_mst_dpcd_read() - read a series of bytes from the DPCD via sideband
1493 * @aux: Fake sideband AUX CH
1494 * @offset: address of the (first) register to read
1495 * @buffer: buffer to store the register values
1496 * @size: number of bytes in @buffer
1497 *
1498 * Performs the same functionality for remote devices via
1499 * sideband messaging as drm_dp_dpcd_read() does for local
1500 * devices via actual AUX CH.
1501 *
1502 * Return: Number of bytes read, or negative error code on failure.
1503 */
1504ssize_t drm_dp_mst_dpcd_read(struct drm_dp_aux *aux,
1505			     unsigned int offset, void *buffer, size_t size)
1506{
1507	struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
1508						    aux);
1509
1510	return drm_dp_send_dpcd_read(port->mgr, port,
1511				     offset, size, buffer);
1512}
1513
1514/**
1515 * drm_dp_mst_dpcd_write() - write a series of bytes to the DPCD via sideband
1516 * @aux: Fake sideband AUX CH
1517 * @offset: address of the (first) register to write
1518 * @buffer: buffer containing the values to write
1519 * @size: number of bytes in @buffer
1520 *
1521 * Performs the same functionality for remote devices via
1522 * sideband messaging as drm_dp_dpcd_write() does for local
1523 * devices via actual AUX CH.
1524 *
1525 * Return: 0 on success, negative error code on failure.
1526 */
1527ssize_t drm_dp_mst_dpcd_write(struct drm_dp_aux *aux,
1528			      unsigned int offset, void *buffer, size_t size)
1529{
1530	struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port,
1531						    aux);
1532
1533	return drm_dp_send_dpcd_write(port->mgr, port,
1534				      offset, size, buffer);
1535}
1536
1537static void drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
1538{
1539	int ret;
1540
1541	memcpy(mstb->guid, guid, 16);
1542
1543	if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
1544		if (mstb->port_parent) {
1545			ret = drm_dp_send_dpcd_write(
1546					mstb->mgr,
1547					mstb->port_parent,
1548					DP_GUID,
1549					16,
1550					mstb->guid);
1551		} else {
1552
1553			ret = drm_dp_dpcd_write(
1554					mstb->mgr->aux,
1555					DP_GUID,
1556					mstb->guid,
1557					16);
1558		}
1559	}
1560}
1561
1562static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
1563				int pnum,
1564				char *proppath,
1565				size_t proppath_size)
1566{
1567	int i;
1568	char temp[8];
1569	snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
1570	for (i = 0; i < (mstb->lct - 1); i++) {
1571		int shift = (i % 2) ? 0 : 4;
1572		int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
1573		snprintf(temp, sizeof(temp), "-%d", port_num);
1574		strlcat(proppath, temp, proppath_size);
1575	}
1576	snprintf(temp, sizeof(temp), "-%d", pnum);
1577	strlcat(proppath, temp, proppath_size);
1578}
1579
1580/**
1581 * drm_dp_mst_connector_late_register() - Late MST connector registration
1582 * @connector: The MST connector
1583 * @port: The MST port for this connector
1584 *
1585 * Helper to register the remote aux device for this MST port. Drivers should
1586 * call this from their mst connector's late_register hook to enable MST aux
1587 * devices.
1588 *
1589 * Return: 0 on success, negative error code on failure.
1590 */
1591int drm_dp_mst_connector_late_register(struct drm_connector *connector,
1592				       struct drm_dp_mst_port *port)
1593{
1594	DRM_DEBUG_KMS("registering %s remote bus for %s\n",
1595		      port->aux.name, connector->kdev->kobj.name);
1596
1597	port->aux.dev = connector->kdev;
1598	return drm_dp_aux_register_devnode(&port->aux);
1599}
1600EXPORT_SYMBOL(drm_dp_mst_connector_late_register);
1601
1602/**
1603 * drm_dp_mst_connector_early_unregister() - Early MST connector unregistration
1604 * @connector: The MST connector
1605 * @port: The MST port for this connector
1606 *
1607 * Helper to unregister the remote aux device for this MST port, registered by
1608 * drm_dp_mst_connector_late_register(). Drivers should call this from their mst
1609 * connector's early_unregister hook.
1610 */
1611void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
1612					   struct drm_dp_mst_port *port)
1613{
1614	DRM_DEBUG_KMS("unregistering %s remote bus for %s\n",
1615		      port->aux.name, connector->kdev->kobj.name);
1616	drm_dp_aux_unregister_devnode(&port->aux);
1617}
1618EXPORT_SYMBOL(drm_dp_mst_connector_early_unregister);
1619
1620static void drm_dp_add_port(struct drm_dp_mst_branch *mstb,
1621			    struct drm_device *dev,
1622			    struct drm_dp_link_addr_reply_port *port_msg)
1623{
1624	struct drm_dp_mst_port *port;
1625	bool ret;
1626	bool created = false;
1627	int old_pdt = 0;
1628	int old_ddps = 0;
1629
1630	port = drm_dp_get_port(mstb, port_msg->port_number);
1631	if (!port) {
1632		port = kzalloc(sizeof(*port), GFP_KERNEL);
1633		if (!port)
1634			return;
1635		kref_init(&port->topology_kref);
1636		kref_init(&port->malloc_kref);
1637		port->parent = mstb;
1638		port->port_num = port_msg->port_number;
1639		port->mgr = mstb->mgr;
1640		port->aux.name = "DPMST";
1641		port->aux.dev = dev->dev;
1642		port->aux.is_remote = true;
1643
1644		/*
1645		 * Make sure the memory allocation for our parent branch stays
1646		 * around until our own memory allocation is released
1647		 */
1648		drm_dp_mst_get_mstb_malloc(mstb);
1649
1650		created = true;
1651	} else {
1652		old_pdt = port->pdt;
1653		old_ddps = port->ddps;
1654	}
1655
1656	port->pdt = port_msg->peer_device_type;
1657	port->input = port_msg->input_port;
1658	port->mcs = port_msg->mcs;
1659	port->ddps = port_msg->ddps;
1660	port->ldps = port_msg->legacy_device_plug_status;
1661	port->dpcd_rev = port_msg->dpcd_revision;
1662	port->num_sdp_streams = port_msg->num_sdp_streams;
1663	port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
1664
1665	/* manage mstb port lists with mgr lock - take a reference
1666	   for this list */
1667	if (created) {
1668		mutex_lock(&mstb->mgr->lock);
1669		drm_dp_mst_topology_get_port(port);
1670		list_add(&port->next, &mstb->ports);
1671		mutex_unlock(&mstb->mgr->lock);
1672	}
1673
1674	if (old_ddps != port->ddps) {
1675		if (port->ddps) {
1676			if (!port->input) {
1677				drm_dp_send_enum_path_resources(mstb->mgr,
1678								mstb, port);
1679			}
1680		} else {
1681			port->available_pbn = 0;
1682		}
1683	}
1684
1685	if (old_pdt != port->pdt && !port->input) {
1686		drm_dp_port_teardown_pdt(port, old_pdt);
1687
1688		ret = drm_dp_port_setup_pdt(port);
1689		if (ret == true)
1690			drm_dp_send_link_address(mstb->mgr, port->mstb);
1691	}
1692
1693	if (created && !port->input) {
1694		char proppath[255];
1695
1696		build_mst_prop_path(mstb, port->port_num, proppath,
1697				    sizeof(proppath));
1698		port->connector = (*mstb->mgr->cbs->add_connector)(mstb->mgr,
1699								   port,
1700								   proppath);
1701		if (!port->connector) {
1702			/* remove it from the port list */
1703			mutex_lock(&mstb->mgr->lock);
1704			list_del(&port->next);
1705			mutex_unlock(&mstb->mgr->lock);
1706			/* drop port list reference */
1707			drm_dp_mst_topology_put_port(port);
1708			goto out;
1709		}
1710		if ((port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV ||
1711		     port->pdt == DP_PEER_DEVICE_SST_SINK) &&
1712		    port->port_num >= DP_MST_LOGICAL_PORT_0) {
1713			port->cached_edid = drm_get_edid(port->connector,
1714							 &port->aux.ddc);
1715			drm_connector_set_tile_property(port->connector);
1716		}
1717		(*mstb->mgr->cbs->register_connector)(port->connector);
1718	}
1719
1720out:
1721	/* put reference to this port */
1722	drm_dp_mst_topology_put_port(port);
1723}
1724
1725static void drm_dp_update_port(struct drm_dp_mst_branch *mstb,
1726			       struct drm_dp_connection_status_notify *conn_stat)
1727{
1728	struct drm_dp_mst_port *port;
1729	int old_pdt;
1730	int old_ddps;
1731	bool dowork = false;
1732	port = drm_dp_get_port(mstb, conn_stat->port_number);
1733	if (!port)
1734		return;
1735
1736	old_ddps = port->ddps;
1737	old_pdt = port->pdt;
1738	port->pdt = conn_stat->peer_device_type;
1739	port->mcs = conn_stat->message_capability_status;
1740	port->ldps = conn_stat->legacy_device_plug_status;
1741	port->ddps = conn_stat->displayport_device_plug_status;
1742
1743	if (old_ddps != port->ddps) {
1744		if (port->ddps) {
1745			dowork = true;
1746		} else {
1747			port->available_pbn = 0;
1748		}
1749	}
1750	if (old_pdt != port->pdt && !port->input) {
1751		drm_dp_port_teardown_pdt(port, old_pdt);
1752
1753		if (drm_dp_port_setup_pdt(port))
1754			dowork = true;
1755	}
1756
1757	drm_dp_mst_topology_put_port(port);
1758	if (dowork)
1759		queue_work(system_long_wq, &mstb->mgr->work);
1760
1761}
1762
1763static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
1764							       u8 lct, u8 *rad)
1765{
1766	struct drm_dp_mst_branch *mstb;
1767	struct drm_dp_mst_port *port;
1768	int i, ret;
1769	/* find the port by iterating down */
1770
1771	mutex_lock(&mgr->lock);
1772	mstb = mgr->mst_primary;
1773
1774	if (!mstb)
1775		goto out;
1776
1777	for (i = 0; i < lct - 1; i++) {
1778		int shift = (i % 2) ? 0 : 4;
1779		int port_num = (rad[i / 2] >> shift) & 0xf;
1780
1781		list_for_each_entry(port, &mstb->ports, next) {
1782			if (port->port_num == port_num) {
1783				mstb = port->mstb;
1784				if (!mstb) {
1785					DRM_ERROR("failed to lookup MSTB with lct %d, rad %02x\n", lct, rad[0]);
1786					goto out;
1787				}
1788
1789				break;
1790			}
1791		}
1792	}
1793	ret = drm_dp_mst_topology_try_get_mstb(mstb);
1794	if (!ret)
1795		mstb = NULL;
1796out:
1797	mutex_unlock(&mgr->lock);
1798	return mstb;
1799}
1800
1801static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
1802	struct drm_dp_mst_branch *mstb,
1803	uint8_t *guid)
1804{
1805	struct drm_dp_mst_branch *found_mstb;
1806	struct drm_dp_mst_port *port;
1807
1808	if (memcmp(mstb->guid, guid, 16) == 0)
1809		return mstb;
1810
1811
1812	list_for_each_entry(port, &mstb->ports, next) {
1813		if (!port->mstb)
1814			continue;
1815
1816		found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid);
1817
1818		if (found_mstb)
1819			return found_mstb;
1820	}
1821
1822	return NULL;
1823}
1824
1825static struct drm_dp_mst_branch *
1826drm_dp_get_mst_branch_device_by_guid(struct drm_dp_mst_topology_mgr *mgr,
1827				     uint8_t *guid)
1828{
1829	struct drm_dp_mst_branch *mstb;
1830	int ret;
1831
1832	/* find the port by iterating down */
1833	mutex_lock(&mgr->lock);
1834
1835	mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
1836	if (mstb) {
1837		ret = drm_dp_mst_topology_try_get_mstb(mstb);
1838		if (!ret)
1839			mstb = NULL;
1840	}
1841
1842	mutex_unlock(&mgr->lock);
1843	return mstb;
1844}
1845
1846static void drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
1847					       struct drm_dp_mst_branch *mstb)
1848{
1849	struct drm_dp_mst_port *port;
1850	struct drm_dp_mst_branch *mstb_child;
1851	if (!mstb->link_address_sent)
1852		drm_dp_send_link_address(mgr, mstb);
1853
1854	list_for_each_entry(port, &mstb->ports, next) {
1855		if (port->input)
1856			continue;
1857
1858		if (!port->ddps)
1859			continue;
1860
1861		if (!port->available_pbn)
1862			drm_dp_send_enum_path_resources(mgr, mstb, port);
1863
1864		if (port->mstb) {
1865			mstb_child = drm_dp_mst_topology_get_mstb_validated(
1866			    mgr, port->mstb);
1867			if (mstb_child) {
1868				drm_dp_check_and_send_link_address(mgr, mstb_child);
1869				drm_dp_mst_topology_put_mstb(mstb_child);
1870			}
1871		}
1872	}
1873}
1874
1875static void drm_dp_mst_link_probe_work(struct work_struct *work)
1876{
1877	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, work);
1878	struct drm_dp_mst_branch *mstb;
1879	int ret;
1880
1881	mutex_lock(&mgr->lock);
1882	mstb = mgr->mst_primary;
1883	if (mstb) {
1884		ret = drm_dp_mst_topology_try_get_mstb(mstb);
1885		if (!ret)
1886			mstb = NULL;
1887	}
1888	mutex_unlock(&mgr->lock);
1889	if (mstb) {
1890		drm_dp_check_and_send_link_address(mgr, mstb);
1891		drm_dp_mst_topology_put_mstb(mstb);
1892	}
1893}
1894
1895static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
1896				 u8 *guid)
1897{
1898	u64 salt;
1899
1900	if (memchr_inv(guid, 0, 16))
1901		return true;
1902
1903	salt = get_jiffies_64();
1904
1905	memcpy(&guid[0], &salt, sizeof(u64));
1906	memcpy(&guid[8], &salt, sizeof(u64));
1907
1908	return false;
1909}
1910
 
1911static int build_dpcd_read(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32 offset, u8 num_bytes)
1912{
1913	struct drm_dp_sideband_msg_req_body req;
1914
1915	req.req_type = DP_REMOTE_DPCD_READ;
1916	req.u.dpcd_read.port_number = port_num;
1917	req.u.dpcd_read.dpcd_address = offset;
1918	req.u.dpcd_read.num_bytes = num_bytes;
1919	drm_dp_encode_sideband_req(&req, msg);
1920
1921	return 0;
1922}
 
1923
1924static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
1925				    bool up, u8 *msg, int len)
1926{
1927	int ret;
1928	int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
1929	int tosend, total, offset;
1930	int retries = 0;
1931
1932retry:
1933	total = len;
1934	offset = 0;
1935	do {
1936		tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
1937
1938		ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
1939					&msg[offset],
1940					tosend);
1941		if (ret != tosend) {
1942			if (ret == -EIO && retries < 5) {
1943				retries++;
1944				goto retry;
1945			}
1946			DRM_DEBUG_KMS("failed to dpcd write %d %d\n", tosend, ret);
1947
1948			return -EIO;
1949		}
1950		offset += tosend;
1951		total -= tosend;
1952	} while (total > 0);
1953	return 0;
1954}
1955
1956static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
1957				  struct drm_dp_sideband_msg_tx *txmsg)
1958{
1959	struct drm_dp_mst_branch *mstb = txmsg->dst;
1960	u8 req_type;
1961
1962	/* both msg slots are full */
1963	if (txmsg->seqno == -1) {
1964		if (mstb->tx_slots[0] && mstb->tx_slots[1]) {
1965			DRM_DEBUG_KMS("%s: failed to find slot\n", __func__);
1966			return -EAGAIN;
1967		}
1968		if (mstb->tx_slots[0] == NULL && mstb->tx_slots[1] == NULL) {
1969			txmsg->seqno = mstb->last_seqno;
1970			mstb->last_seqno ^= 1;
1971		} else if (mstb->tx_slots[0] == NULL)
1972			txmsg->seqno = 0;
1973		else
1974			txmsg->seqno = 1;
1975		mstb->tx_slots[txmsg->seqno] = txmsg;
1976	}
1977
1978	req_type = txmsg->msg[0] & 0x7f;
1979	if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
1980		req_type == DP_RESOURCE_STATUS_NOTIFY)
1981		hdr->broadcast = 1;
1982	else
1983		hdr->broadcast = 0;
1984	hdr->path_msg = txmsg->path_msg;
1985	hdr->lct = mstb->lct;
1986	hdr->lcr = mstb->lct - 1;
1987	if (mstb->lct > 1)
1988		memcpy(hdr->rad, mstb->rad, mstb->lct / 2);
1989	hdr->seqno = txmsg->seqno;
1990	return 0;
1991}
1992/*
1993 * process a single block of the next message in the sideband queue
1994 */
1995static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
1996				   struct drm_dp_sideband_msg_tx *txmsg,
1997				   bool up)
1998{
1999	u8 chunk[48];
2000	struct drm_dp_sideband_msg_hdr hdr;
2001	int len, space, idx, tosend;
2002	int ret;
2003
2004	memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
2005
2006	if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED) {
2007		txmsg->seqno = -1;
2008		txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
2009	}
2010
2011	/* make hdr from dst mst - for replies use seqno
2012	   otherwise assign one */
2013	ret = set_hdr_from_dst_qlock(&hdr, txmsg);
2014	if (ret < 0)
2015		return ret;
2016
2017	/* amount left to send in this message */
2018	len = txmsg->cur_len - txmsg->cur_offset;
2019
2020	/* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
2021	space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
2022
2023	tosend = min(len, space);
2024	if (len == txmsg->cur_len)
2025		hdr.somt = 1;
2026	if (space >= len)
2027		hdr.eomt = 1;
2028
2029
2030	hdr.msg_len = tosend + 1;
2031	drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
2032	memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
2033	/* add crc at end */
2034	drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
2035	idx += tosend + 1;
2036
2037	ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
2038	if (ret) {
2039		DRM_DEBUG_KMS("sideband msg failed to send\n");
2040		return ret;
2041	}
2042
2043	txmsg->cur_offset += tosend;
2044	if (txmsg->cur_offset == txmsg->cur_len) {
2045		txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
2046		return 1;
2047	}
2048	return 0;
2049}
2050
2051static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
2052{
2053	struct drm_dp_sideband_msg_tx *txmsg;
2054	int ret;
2055
2056	WARN_ON(!mutex_is_locked(&mgr->qlock));
2057
2058	/* construct a chunk from the first msg in the tx_msg queue */
2059	if (list_empty(&mgr->tx_msg_downq))
2060		return;
2061
2062	txmsg = list_first_entry(&mgr->tx_msg_downq, struct drm_dp_sideband_msg_tx, next);
2063	ret = process_single_tx_qlock(mgr, txmsg, false);
2064	if (ret == 1) {
2065		/* txmsg is sent it should be in the slots now */
2066		list_del(&txmsg->next);
2067	} else if (ret) {
2068		DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
2069		list_del(&txmsg->next);
2070		if (txmsg->seqno != -1)
2071			txmsg->dst->tx_slots[txmsg->seqno] = NULL;
2072		txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
2073		wake_up_all(&mgr->tx_waitq);
2074	}
2075}
2076
2077/* called holding qlock */
2078static void process_single_up_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
2079				       struct drm_dp_sideband_msg_tx *txmsg)
2080{
2081	int ret;
2082
2083	/* construct a chunk from the first msg in the tx_msg queue */
2084	ret = process_single_tx_qlock(mgr, txmsg, true);
2085
2086	if (ret != 1)
2087		DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
2088
2089	if (txmsg->seqno != -1) {
2090		WARN_ON((unsigned int)txmsg->seqno >
2091			ARRAY_SIZE(txmsg->dst->tx_slots));
2092		txmsg->dst->tx_slots[txmsg->seqno] = NULL;
2093	}
2094}
2095
2096static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
2097				 struct drm_dp_sideband_msg_tx *txmsg)
2098{
2099	mutex_lock(&mgr->qlock);
2100	list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
2101	if (list_is_singular(&mgr->tx_msg_downq))
2102		process_single_down_tx_qlock(mgr);
2103	mutex_unlock(&mgr->qlock);
2104}
2105
2106static void drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
2107				     struct drm_dp_mst_branch *mstb)
2108{
2109	int len;
2110	struct drm_dp_sideband_msg_tx *txmsg;
2111	int ret;
2112
2113	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2114	if (!txmsg)
2115		return;
2116
2117	txmsg->dst = mstb;
2118	len = build_link_address(txmsg);
2119
2120	mstb->link_address_sent = true;
2121	drm_dp_queue_down_tx(mgr, txmsg);
2122
2123	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2124	if (ret > 0) {
2125		int i;
2126
2127		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
2128			DRM_DEBUG_KMS("link address nak received\n");
2129		} else {
2130			DRM_DEBUG_KMS("link address reply: %d\n", txmsg->reply.u.link_addr.nports);
2131			for (i = 0; i < txmsg->reply.u.link_addr.nports; i++) {
2132				DRM_DEBUG_KMS("port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, mcs: %d, ddps: %d, ldps %d, sdp %d/%d\n", i,
2133				       txmsg->reply.u.link_addr.ports[i].input_port,
2134				       txmsg->reply.u.link_addr.ports[i].peer_device_type,
2135				       txmsg->reply.u.link_addr.ports[i].port_number,
2136				       txmsg->reply.u.link_addr.ports[i].dpcd_revision,
2137				       txmsg->reply.u.link_addr.ports[i].mcs,
2138				       txmsg->reply.u.link_addr.ports[i].ddps,
2139				       txmsg->reply.u.link_addr.ports[i].legacy_device_plug_status,
2140				       txmsg->reply.u.link_addr.ports[i].num_sdp_streams,
2141				       txmsg->reply.u.link_addr.ports[i].num_sdp_stream_sinks);
2142			}
2143
2144			drm_dp_check_mstb_guid(mstb, txmsg->reply.u.link_addr.guid);
2145
2146			for (i = 0; i < txmsg->reply.u.link_addr.nports; i++) {
2147				drm_dp_add_port(mstb, mgr->dev, &txmsg->reply.u.link_addr.ports[i]);
2148			}
2149			drm_kms_helper_hotplug_event(mgr->dev);
2150		}
2151	} else {
2152		mstb->link_address_sent = false;
2153		DRM_DEBUG_KMS("link address failed %d\n", ret);
2154	}
2155
2156	kfree(txmsg);
2157}
2158
2159static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
2160					   struct drm_dp_mst_branch *mstb,
2161					   struct drm_dp_mst_port *port)
2162{
2163	int len;
2164	struct drm_dp_sideband_msg_tx *txmsg;
2165	int ret;
2166
2167	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2168	if (!txmsg)
2169		return -ENOMEM;
2170
2171	txmsg->dst = mstb;
2172	len = build_enum_path_resources(txmsg, port->port_num);
2173
2174	drm_dp_queue_down_tx(mgr, txmsg);
2175
2176	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2177	if (ret > 0) {
2178		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
2179			DRM_DEBUG_KMS("enum path resources nak received\n");
2180		} else {
2181			if (port->port_num != txmsg->reply.u.path_resources.port_number)
2182				DRM_ERROR("got incorrect port in response\n");
2183			DRM_DEBUG_KMS("enum path resources %d: %d %d\n", txmsg->reply.u.path_resources.port_number, txmsg->reply.u.path_resources.full_payload_bw_number,
2184			       txmsg->reply.u.path_resources.avail_payload_bw_number);
2185			port->available_pbn = txmsg->reply.u.path_resources.avail_payload_bw_number;
2186		}
2187	}
2188
2189	kfree(txmsg);
2190	return 0;
2191}
2192
2193static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb)
2194{
2195	if (!mstb->port_parent)
2196		return NULL;
2197
2198	if (mstb->port_parent->mstb != mstb)
2199		return mstb->port_parent;
2200
2201	return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
2202}
2203
2204/*
2205 * Searches upwards in the topology starting from mstb to try to find the
2206 * closest available parent of mstb that's still connected to the rest of the
2207 * topology. This can be used in order to perform operations like releasing
2208 * payloads, where the branch device which owned the payload may no longer be
2209 * around and thus would require that the payload on the last living relative
2210 * be freed instead.
2211 */
2212static struct drm_dp_mst_branch *
2213drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
2214					struct drm_dp_mst_branch *mstb,
2215					int *port_num)
2216{
2217	struct drm_dp_mst_branch *rmstb = NULL;
2218	struct drm_dp_mst_port *found_port;
2219
2220	mutex_lock(&mgr->lock);
2221	if (!mgr->mst_primary)
2222		goto out;
2223
2224	do {
2225		found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
2226		if (!found_port)
2227			break;
2228
2229		if (drm_dp_mst_topology_try_get_mstb(found_port->parent)) {
2230			rmstb = found_port->parent;
 
2231			*port_num = found_port->port_num;
2232		} else {
2233			/* Search again, starting from this parent */
2234			mstb = found_port->parent;
2235		}
2236	} while (!rmstb);
2237out:
2238	mutex_unlock(&mgr->lock);
2239	return rmstb;
2240}
2241
2242static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
2243				   struct drm_dp_mst_port *port,
2244				   int id,
2245				   int pbn)
2246{
2247	struct drm_dp_sideband_msg_tx *txmsg;
2248	struct drm_dp_mst_branch *mstb;
2249	int len, ret, port_num;
2250	u8 sinks[DRM_DP_MAX_SDP_STREAMS];
2251	int i;
2252
 
 
 
 
2253	port_num = port->port_num;
2254	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
2255	if (!mstb) {
2256		mstb = drm_dp_get_last_connected_port_and_mstb(mgr,
2257							       port->parent,
2258							       &port_num);
2259
2260		if (!mstb)
 
2261			return -EINVAL;
 
2262	}
2263
2264	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2265	if (!txmsg) {
2266		ret = -ENOMEM;
2267		goto fail_put;
2268	}
2269
2270	for (i = 0; i < port->num_sdp_streams; i++)
2271		sinks[i] = i;
2272
2273	txmsg->dst = mstb;
2274	len = build_allocate_payload(txmsg, port_num,
2275				     id,
2276				     pbn, port->num_sdp_streams, sinks);
2277
2278	drm_dp_queue_down_tx(mgr, txmsg);
2279
2280	/*
2281	 * FIXME: there is a small chance that between getting the last
2282	 * connected mstb and sending the payload message, the last connected
2283	 * mstb could also be removed from the topology. In the future, this
2284	 * needs to be fixed by restarting the
2285	 * drm_dp_get_last_connected_port_and_mstb() search in the event of a
2286	 * timeout if the topology is still connected to the system.
2287	 */
2288	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2289	if (ret > 0) {
2290		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
2291			ret = -EINVAL;
2292		else
2293			ret = 0;
2294	}
2295	kfree(txmsg);
2296fail_put:
2297	drm_dp_mst_topology_put_mstb(mstb);
 
2298	return ret;
2299}
2300
2301int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
2302				 struct drm_dp_mst_port *port, bool power_up)
2303{
2304	struct drm_dp_sideband_msg_tx *txmsg;
2305	int len, ret;
2306
2307	port = drm_dp_mst_topology_get_port_validated(mgr, port);
2308	if (!port)
2309		return -EINVAL;
2310
2311	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2312	if (!txmsg) {
2313		drm_dp_mst_topology_put_port(port);
2314		return -ENOMEM;
2315	}
2316
2317	txmsg->dst = port->parent;
2318	len = build_power_updown_phy(txmsg, port->port_num, power_up);
2319	drm_dp_queue_down_tx(mgr, txmsg);
2320
2321	ret = drm_dp_mst_wait_tx_reply(port->parent, txmsg);
2322	if (ret > 0) {
2323		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
2324			ret = -EINVAL;
2325		else
2326			ret = 0;
2327	}
2328	kfree(txmsg);
2329	drm_dp_mst_topology_put_port(port);
2330
2331	return ret;
2332}
2333EXPORT_SYMBOL(drm_dp_send_power_updown_phy);
2334
2335static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
2336				       int id,
2337				       struct drm_dp_payload *payload)
2338{
2339	int ret;
2340
2341	ret = drm_dp_dpcd_write_payload(mgr, id, payload);
2342	if (ret < 0) {
2343		payload->payload_state = 0;
2344		return ret;
2345	}
2346	payload->payload_state = DP_PAYLOAD_LOCAL;
2347	return 0;
2348}
2349
2350static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
2351				       struct drm_dp_mst_port *port,
2352				       int id,
2353				       struct drm_dp_payload *payload)
2354{
2355	int ret;
2356	ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
2357	if (ret < 0)
2358		return ret;
2359	payload->payload_state = DP_PAYLOAD_REMOTE;
2360	return ret;
2361}
2362
2363static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
2364					struct drm_dp_mst_port *port,
2365					int id,
2366					struct drm_dp_payload *payload)
2367{
2368	DRM_DEBUG_KMS("\n");
2369	/* it's okay for these to fail */
2370	if (port) {
2371		drm_dp_payload_send_msg(mgr, port, id, 0);
2372	}
2373
2374	drm_dp_dpcd_write_payload(mgr, id, payload);
2375	payload->payload_state = DP_PAYLOAD_DELETE_LOCAL;
2376	return 0;
2377}
2378
2379static int drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
2380					int id,
2381					struct drm_dp_payload *payload)
2382{
2383	payload->payload_state = 0;
2384	return 0;
2385}
2386
2387/**
2388 * drm_dp_update_payload_part1() - Execute payload update part 1
2389 * @mgr: manager to use.
2390 *
2391 * This iterates over all proposed virtual channels, and tries to
2392 * allocate space in the link for them. For 0->slots transitions,
2393 * this step just writes the VCPI to the MST device. For slots->0
2394 * transitions, this writes the updated VCPIs and removes the
2395 * remote VC payloads.
2396 *
2397 * after calling this the driver should generate ACT and payload
2398 * packets.
2399 */
2400int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
2401{
2402	struct drm_dp_payload req_payload;
2403	struct drm_dp_mst_port *port;
2404	int i, j;
2405	int cur_slots = 1;
 
 
2406
2407	mutex_lock(&mgr->payload_lock);
2408	for (i = 0; i < mgr->max_payloads; i++) {
2409		struct drm_dp_vcpi *vcpi = mgr->proposed_vcpis[i];
2410		struct drm_dp_payload *payload = &mgr->payloads[i];
2411		bool put_port = false;
2412
2413		/* solve the current payloads - compare to the hw ones
2414		   - update the hw view */
2415		req_payload.start_slot = cur_slots;
2416		if (vcpi) {
2417			port = container_of(vcpi, struct drm_dp_mst_port,
2418					    vcpi);
2419
2420			/* Validated ports don't matter if we're releasing
2421			 * VCPI
2422			 */
2423			if (vcpi->num_slots) {
2424				port = drm_dp_mst_topology_get_port_validated(
2425				    mgr, port);
2426				if (!port) {
2427					mutex_unlock(&mgr->payload_lock);
2428					return -EINVAL;
2429				}
2430				put_port = true;
2431			}
2432
2433			req_payload.num_slots = vcpi->num_slots;
2434			req_payload.vcpi = vcpi->vcpi;
2435		} else {
2436			port = NULL;
2437			req_payload.num_slots = 0;
2438		}
2439
2440		payload->start_slot = req_payload.start_slot;
 
 
2441		/* work out what is required to happen with this payload */
2442		if (payload->num_slots != req_payload.num_slots) {
2443
2444			/* need to push an update for this payload */
2445			if (req_payload.num_slots) {
2446				drm_dp_create_payload_step1(mgr, vcpi->vcpi,
2447							    &req_payload);
2448				payload->num_slots = req_payload.num_slots;
2449				payload->vcpi = req_payload.vcpi;
2450
2451			} else if (payload->num_slots) {
2452				payload->num_slots = 0;
2453				drm_dp_destroy_payload_step1(mgr, port,
2454							     payload->vcpi,
2455							     payload);
2456				req_payload.payload_state =
2457					payload->payload_state;
2458				payload->start_slot = 0;
2459			}
2460			payload->payload_state = req_payload.payload_state;
2461		}
2462		cur_slots += req_payload.num_slots;
2463
2464		if (put_port)
2465			drm_dp_mst_topology_put_port(port);
2466	}
2467
2468	for (i = 0; i < mgr->max_payloads; i++) {
2469		if (mgr->payloads[i].payload_state != DP_PAYLOAD_DELETE_LOCAL)
2470			continue;
2471
2472		DRM_DEBUG_KMS("removing payload %d\n", i);
2473		for (j = i; j < mgr->max_payloads - 1; j++) {
2474			mgr->payloads[j] = mgr->payloads[j + 1];
2475			mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
2476
2477			if (mgr->proposed_vcpis[j] &&
2478			    mgr->proposed_vcpis[j]->num_slots) {
2479				set_bit(j + 1, &mgr->payload_mask);
2480			} else {
2481				clear_bit(j + 1, &mgr->payload_mask);
2482			}
2483		}
 
 
2484
2485		memset(&mgr->payloads[mgr->max_payloads - 1], 0,
2486		       sizeof(struct drm_dp_payload));
2487		mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
2488		clear_bit(mgr->max_payloads, &mgr->payload_mask);
2489	}
2490	mutex_unlock(&mgr->payload_lock);
2491
2492	return 0;
2493}
2494EXPORT_SYMBOL(drm_dp_update_payload_part1);
2495
2496/**
2497 * drm_dp_update_payload_part2() - Execute payload update part 2
2498 * @mgr: manager to use.
2499 *
2500 * This iterates over all proposed virtual channels, and tries to
2501 * allocate space in the link for them. For 0->slots transitions,
2502 * this step writes the remote VC payload commands. For slots->0
2503 * this just resets some internal state.
2504 */
2505int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
2506{
2507	struct drm_dp_mst_port *port;
2508	int i;
2509	int ret = 0;
2510	mutex_lock(&mgr->payload_lock);
2511	for (i = 0; i < mgr->max_payloads; i++) {
2512
2513		if (!mgr->proposed_vcpis[i])
2514			continue;
2515
2516		port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
2517
2518		DRM_DEBUG_KMS("payload %d %d\n", i, mgr->payloads[i].payload_state);
2519		if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
2520			ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
2521		} else if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
2522			ret = drm_dp_destroy_payload_step2(mgr, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
2523		}
2524		if (ret) {
2525			mutex_unlock(&mgr->payload_lock);
2526			return ret;
2527		}
2528	}
2529	mutex_unlock(&mgr->payload_lock);
2530	return 0;
2531}
2532EXPORT_SYMBOL(drm_dp_update_payload_part2);
2533
 
2534static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
2535				 struct drm_dp_mst_port *port,
2536				 int offset, int size, u8 *bytes)
2537{
2538	int len;
2539	int ret = 0;
2540	struct drm_dp_sideband_msg_tx *txmsg;
2541	struct drm_dp_mst_branch *mstb;
2542
2543	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
2544	if (!mstb)
2545		return -EINVAL;
2546
2547	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2548	if (!txmsg) {
2549		ret = -ENOMEM;
2550		goto fail_put;
2551	}
2552
2553	len = build_dpcd_read(txmsg, port->port_num, offset, size);
2554	txmsg->dst = port->parent;
2555
2556	drm_dp_queue_down_tx(mgr, txmsg);
2557
2558	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2559	if (ret < 0)
2560		goto fail_free;
2561
2562	/* DPCD read should never be NACKed */
2563	if (txmsg->reply.reply_type == 1) {
2564		DRM_ERROR("mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n",
2565			  mstb, port->port_num, offset, size);
2566		ret = -EIO;
2567		goto fail_free;
2568	}
2569
2570	if (txmsg->reply.u.remote_dpcd_read_ack.num_bytes != size) {
2571		ret = -EPROTO;
2572		goto fail_free;
2573	}
2574
2575	ret = min_t(size_t, txmsg->reply.u.remote_dpcd_read_ack.num_bytes,
2576		    size);
2577	memcpy(bytes, txmsg->reply.u.remote_dpcd_read_ack.bytes, ret);
2578
2579fail_free:
2580	kfree(txmsg);
2581fail_put:
2582	drm_dp_mst_topology_put_mstb(mstb);
2583
2584	return ret;
2585}
 
2586
2587static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
2588				  struct drm_dp_mst_port *port,
2589				  int offset, int size, u8 *bytes)
2590{
2591	int len;
2592	int ret;
2593	struct drm_dp_sideband_msg_tx *txmsg;
2594	struct drm_dp_mst_branch *mstb;
2595
2596	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
2597	if (!mstb)
2598		return -EINVAL;
2599
2600	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2601	if (!txmsg) {
2602		ret = -ENOMEM;
2603		goto fail_put;
2604	}
2605
2606	len = build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
2607	txmsg->dst = mstb;
2608
2609	drm_dp_queue_down_tx(mgr, txmsg);
2610
2611	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
2612	if (ret > 0) {
2613		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
2614			ret = -EIO;
2615		else
2616			ret = 0;
2617	}
2618	kfree(txmsg);
2619fail_put:
2620	drm_dp_mst_topology_put_mstb(mstb);
2621	return ret;
2622}
2623
2624static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
2625{
2626	struct drm_dp_sideband_msg_reply_body reply;
2627
2628	reply.reply_type = DP_SIDEBAND_REPLY_ACK;
2629	reply.req_type = req_type;
2630	drm_dp_encode_sideband_reply(&reply, msg);
2631	return 0;
2632}
2633
2634static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
2635				    struct drm_dp_mst_branch *mstb,
2636				    int req_type, int seqno, bool broadcast)
2637{
2638	struct drm_dp_sideband_msg_tx *txmsg;
2639
2640	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
2641	if (!txmsg)
2642		return -ENOMEM;
2643
2644	txmsg->dst = mstb;
2645	txmsg->seqno = seqno;
2646	drm_dp_encode_up_ack_reply(txmsg, req_type);
2647
2648	mutex_lock(&mgr->qlock);
2649
2650	process_single_up_tx_qlock(mgr, txmsg);
2651
2652	mutex_unlock(&mgr->qlock);
2653
2654	kfree(txmsg);
2655	return 0;
2656}
2657
2658static bool drm_dp_get_vc_payload_bw(int dp_link_bw,
2659				     int dp_link_count,
2660				     int *out)
2661{
2662	switch (dp_link_bw) {
2663	default:
2664		DRM_DEBUG_KMS("invalid link bandwidth in DPCD: %x (link count: %d)\n",
2665			      dp_link_bw, dp_link_count);
2666		return false;
2667
2668	case DP_LINK_BW_1_62:
2669		*out = 3 * dp_link_count;
2670		break;
2671	case DP_LINK_BW_2_7:
2672		*out = 5 * dp_link_count;
2673		break;
2674	case DP_LINK_BW_5_4:
2675		*out = 10 * dp_link_count;
2676		break;
2677	case DP_LINK_BW_8_1:
2678		*out = 15 * dp_link_count;
2679		break;
2680	}
2681	return true;
2682}
2683
2684/**
2685 * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
2686 * @mgr: manager to set state for
2687 * @mst_state: true to enable MST on this connector - false to disable.
2688 *
2689 * This is called by the driver when it detects an MST capable device plugged
2690 * into a DP MST capable port, or when a DP MST capable device is unplugged.
2691 */
2692int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
2693{
2694	int ret = 0;
2695	struct drm_dp_mst_branch *mstb = NULL;
2696
2697	mutex_lock(&mgr->lock);
2698	if (mst_state == mgr->mst_state)
2699		goto out_unlock;
2700
2701	mgr->mst_state = mst_state;
2702	/* set the device into MST mode */
2703	if (mst_state) {
2704		WARN_ON(mgr->mst_primary);
2705
2706		/* get dpcd info */
2707		ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, DP_RECEIVER_CAP_SIZE);
2708		if (ret != DP_RECEIVER_CAP_SIZE) {
2709			DRM_DEBUG_KMS("failed to read DPCD\n");
2710			goto out_unlock;
2711		}
2712
2713		if (!drm_dp_get_vc_payload_bw(mgr->dpcd[1],
2714					      mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK,
2715					      &mgr->pbn_div)) {
2716			ret = -EINVAL;
2717			goto out_unlock;
2718		}
2719
2720		/* add initial branch device at LCT 1 */
2721		mstb = drm_dp_add_mst_branch_device(1, NULL);
2722		if (mstb == NULL) {
2723			ret = -ENOMEM;
2724			goto out_unlock;
2725		}
2726		mstb->mgr = mgr;
2727
2728		/* give this the main reference */
2729		mgr->mst_primary = mstb;
2730		drm_dp_mst_topology_get_mstb(mgr->mst_primary);
2731
2732		ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2733							 DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC);
2734		if (ret < 0) {
2735			goto out_unlock;
2736		}
2737
2738		{
2739			struct drm_dp_payload reset_pay;
2740			reset_pay.start_slot = 0;
2741			reset_pay.num_slots = 0x3f;
2742			drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
2743		}
2744
2745		queue_work(system_long_wq, &mgr->work);
2746
2747		ret = 0;
2748	} else {
2749		/* disable MST on the device */
2750		mstb = mgr->mst_primary;
2751		mgr->mst_primary = NULL;
2752		/* this can fail if the device is gone */
2753		drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
2754		ret = 0;
2755		memset(mgr->payloads, 0, mgr->max_payloads * sizeof(struct drm_dp_payload));
2756		mgr->payload_mask = 0;
2757		set_bit(0, &mgr->payload_mask);
2758		mgr->vcpi_mask = 0;
2759	}
2760
2761out_unlock:
2762	mutex_unlock(&mgr->lock);
2763	if (mstb)
2764		drm_dp_mst_topology_put_mstb(mstb);
2765	return ret;
2766
2767}
2768EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
2769
2770/**
2771 * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
2772 * @mgr: manager to suspend
2773 *
2774 * This function tells the MST device that we can't handle UP messages
2775 * anymore. This should stop it from sending any since we are suspended.
2776 */
2777void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
2778{
2779	mutex_lock(&mgr->lock);
2780	drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2781			   DP_MST_EN | DP_UPSTREAM_IS_SRC);
2782	mutex_unlock(&mgr->lock);
2783	flush_work(&mgr->work);
2784	flush_work(&mgr->destroy_connector_work);
2785}
2786EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
2787
2788/**
2789 * drm_dp_mst_topology_mgr_resume() - resume the MST manager
2790 * @mgr: manager to resume
2791 *
2792 * This will fetch DPCD and see if the device is still there,
2793 * if it is, it will rewrite the MSTM control bits, and return.
2794 *
2795 * if the device fails this returns -1, and the driver should do
2796 * a full MST reprobe, in case we were undocked.
2797 */
2798int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr)
2799{
2800	int ret = 0;
2801
2802	mutex_lock(&mgr->lock);
2803
2804	if (mgr->mst_primary) {
2805		int sret;
2806		u8 guid[16];
2807
2808		sret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, DP_RECEIVER_CAP_SIZE);
2809		if (sret != DP_RECEIVER_CAP_SIZE) {
2810			DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
2811			ret = -1;
2812			goto out_unlock;
2813		}
2814
2815		ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2816					 DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC);
2817		if (ret < 0) {
2818			DRM_DEBUG_KMS("mst write failed - undocked during suspend?\n");
2819			ret = -1;
2820			goto out_unlock;
2821		}
2822
2823		/* Some hubs forget their guids after they resume */
2824		sret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
2825		if (sret != 16) {
2826			DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
2827			ret = -1;
2828			goto out_unlock;
2829		}
2830		drm_dp_check_mstb_guid(mgr->mst_primary, guid);
2831
2832		ret = 0;
2833	} else
2834		ret = -1;
2835
2836out_unlock:
2837	mutex_unlock(&mgr->lock);
2838	return ret;
2839}
2840EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
2841
2842static bool drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up)
2843{
2844	int len;
2845	u8 replyblock[32];
2846	int replylen, origlen, curreply;
2847	int ret;
2848	struct drm_dp_sideband_msg_rx *msg;
2849	int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE : DP_SIDEBAND_MSG_DOWN_REP_BASE;
2850	msg = up ? &mgr->up_req_recv : &mgr->down_rep_recv;
2851
2852	len = min(mgr->max_dpcd_transaction_bytes, 16);
2853	ret = drm_dp_dpcd_read(mgr->aux, basereg,
2854			       replyblock, len);
2855	if (ret != len) {
2856		DRM_DEBUG_KMS("failed to read DPCD down rep %d %d\n", len, ret);
2857		return false;
2858	}
2859	ret = drm_dp_sideband_msg_build(msg, replyblock, len, true);
2860	if (!ret) {
2861		DRM_DEBUG_KMS("sideband msg build failed %d\n", replyblock[0]);
2862		return false;
2863	}
2864	replylen = msg->curchunk_len + msg->curchunk_hdrlen;
2865
2866	origlen = replylen;
2867	replylen -= len;
2868	curreply = len;
2869	while (replylen > 0) {
2870		len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
2871		ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
2872				    replyblock, len);
2873		if (ret != len) {
2874			DRM_DEBUG_KMS("failed to read a chunk (len %d, ret %d)\n",
2875				      len, ret);
2876			return false;
2877		}
2878
2879		ret = drm_dp_sideband_msg_build(msg, replyblock, len, false);
2880		if (!ret) {
2881			DRM_DEBUG_KMS("failed to build sideband msg\n");
2882			return false;
2883		}
2884
2885		curreply += len;
2886		replylen -= len;
2887	}
2888	return true;
2889}
2890
2891static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
2892{
2893	int ret = 0;
2894
2895	if (!drm_dp_get_one_sb_msg(mgr, false)) {
2896		memset(&mgr->down_rep_recv, 0,
2897		       sizeof(struct drm_dp_sideband_msg_rx));
2898		return 0;
2899	}
2900
2901	if (mgr->down_rep_recv.have_eomt) {
2902		struct drm_dp_sideband_msg_tx *txmsg;
2903		struct drm_dp_mst_branch *mstb;
2904		int slot = -1;
2905		mstb = drm_dp_get_mst_branch_device(mgr,
2906						    mgr->down_rep_recv.initial_hdr.lct,
2907						    mgr->down_rep_recv.initial_hdr.rad);
2908
2909		if (!mstb) {
2910			DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->down_rep_recv.initial_hdr.lct);
2911			memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2912			return 0;
2913		}
2914
2915		/* find the message */
2916		slot = mgr->down_rep_recv.initial_hdr.seqno;
2917		mutex_lock(&mgr->qlock);
2918		txmsg = mstb->tx_slots[slot];
2919		/* remove from slots */
2920		mutex_unlock(&mgr->qlock);
2921
2922		if (!txmsg) {
2923			DRM_DEBUG_KMS("Got MST reply with no msg %p %d %d %02x %02x\n",
2924			       mstb,
2925			       mgr->down_rep_recv.initial_hdr.seqno,
2926			       mgr->down_rep_recv.initial_hdr.lct,
2927				      mgr->down_rep_recv.initial_hdr.rad[0],
2928				      mgr->down_rep_recv.msg[0]);
2929			drm_dp_mst_topology_put_mstb(mstb);
2930			memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2931			return 0;
2932		}
2933
2934		drm_dp_sideband_parse_reply(&mgr->down_rep_recv, &txmsg->reply);
2935
2936		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK)
2937			DRM_DEBUG_KMS("Got NAK reply: req 0x%02x (%s), reason 0x%02x (%s), nak data 0x%02x\n",
2938				      txmsg->reply.req_type,
2939				      drm_dp_mst_req_type_str(txmsg->reply.req_type),
2940				      txmsg->reply.u.nak.reason,
2941				      drm_dp_mst_nak_reason_str(txmsg->reply.u.nak.reason),
2942				      txmsg->reply.u.nak.nak_data);
2943
2944		memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2945		drm_dp_mst_topology_put_mstb(mstb);
2946
2947		mutex_lock(&mgr->qlock);
2948		txmsg->state = DRM_DP_SIDEBAND_TX_RX;
2949		mstb->tx_slots[slot] = NULL;
2950		mutex_unlock(&mgr->qlock);
2951
2952		wake_up_all(&mgr->tx_waitq);
2953	}
2954	return ret;
2955}
2956
2957static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
2958{
2959	int ret = 0;
2960
2961	if (!drm_dp_get_one_sb_msg(mgr, true)) {
2962		memset(&mgr->up_req_recv, 0,
2963		       sizeof(struct drm_dp_sideband_msg_rx));
2964		return 0;
2965	}
2966
2967	if (mgr->up_req_recv.have_eomt) {
2968		struct drm_dp_sideband_msg_req_body msg;
2969		struct drm_dp_mst_branch *mstb = NULL;
2970		bool seqno;
2971
2972		if (!mgr->up_req_recv.initial_hdr.broadcast) {
2973			mstb = drm_dp_get_mst_branch_device(mgr,
2974							    mgr->up_req_recv.initial_hdr.lct,
2975							    mgr->up_req_recv.initial_hdr.rad);
2976			if (!mstb) {
2977				DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
2978				memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2979				return 0;
2980			}
2981		}
2982
2983		seqno = mgr->up_req_recv.initial_hdr.seqno;
2984		drm_dp_sideband_parse_req(&mgr->up_req_recv, &msg);
2985
2986		if (msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
2987			drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, msg.req_type, seqno, false);
2988
2989			if (!mstb)
2990				mstb = drm_dp_get_mst_branch_device_by_guid(mgr, msg.u.conn_stat.guid);
2991
2992			if (!mstb) {
2993				DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
2994				memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2995				return 0;
2996			}
2997
2998			drm_dp_update_port(mstb, &msg.u.conn_stat);
2999
3000			DRM_DEBUG_KMS("Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: %d\n", msg.u.conn_stat.port_number, msg.u.conn_stat.legacy_device_plug_status, msg.u.conn_stat.displayport_device_plug_status, msg.u.conn_stat.message_capability_status, msg.u.conn_stat.input_port, msg.u.conn_stat.peer_device_type);
3001			drm_kms_helper_hotplug_event(mgr->dev);
3002
3003		} else if (msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
3004			drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, msg.req_type, seqno, false);
3005			if (!mstb)
3006				mstb = drm_dp_get_mst_branch_device_by_guid(mgr, msg.u.resource_stat.guid);
3007
3008			if (!mstb) {
3009				DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
3010				memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
3011				return 0;
3012			}
3013
3014			DRM_DEBUG_KMS("Got RSN: pn: %d avail_pbn %d\n", msg.u.resource_stat.port_number, msg.u.resource_stat.available_pbn);
3015		}
3016
3017		if (mstb)
3018			drm_dp_mst_topology_put_mstb(mstb);
3019
3020		memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
3021	}
3022	return ret;
3023}
3024
3025/**
3026 * drm_dp_mst_hpd_irq() - MST hotplug IRQ notify
3027 * @mgr: manager to notify irq for.
3028 * @esi: 4 bytes from SINK_COUNT_ESI
3029 * @handled: whether the hpd interrupt was consumed or not
3030 *
3031 * This should be called from the driver when it detects a short IRQ,
3032 * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
3033 * topology manager will process the sideband messages received as a result
3034 * of this.
3035 */
3036int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled)
3037{
3038	int ret = 0;
3039	int sc;
3040	*handled = false;
3041	sc = esi[0] & 0x3f;
3042
3043	if (sc != mgr->sink_count) {
3044		mgr->sink_count = sc;
3045		*handled = true;
3046	}
3047
3048	if (esi[1] & DP_DOWN_REP_MSG_RDY) {
3049		ret = drm_dp_mst_handle_down_rep(mgr);
3050		*handled = true;
3051	}
3052
3053	if (esi[1] & DP_UP_REQ_MSG_RDY) {
3054		ret |= drm_dp_mst_handle_up_req(mgr);
3055		*handled = true;
3056	}
3057
3058	drm_dp_mst_kick_tx(mgr);
3059	return ret;
3060}
3061EXPORT_SYMBOL(drm_dp_mst_hpd_irq);
3062
3063/**
3064 * drm_dp_mst_detect_port() - get connection status for an MST port
3065 * @connector: DRM connector for this port
3066 * @mgr: manager for this port
3067 * @port: unverified pointer to a port
3068 *
3069 * This returns the current connection state for a port. It validates the
3070 * port pointer still exists so the caller doesn't require a reference
3071 */
3072enum drm_connector_status drm_dp_mst_detect_port(struct drm_connector *connector,
3073						 struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
3074{
3075	enum drm_connector_status status = connector_status_disconnected;
3076
3077	/* we need to search for the port in the mgr in case it's gone */
3078	port = drm_dp_mst_topology_get_port_validated(mgr, port);
3079	if (!port)
3080		return connector_status_disconnected;
3081
3082	if (!port->ddps)
3083		goto out;
3084
3085	switch (port->pdt) {
3086	case DP_PEER_DEVICE_NONE:
3087	case DP_PEER_DEVICE_MST_BRANCHING:
3088		break;
3089
3090	case DP_PEER_DEVICE_SST_SINK:
3091		status = connector_status_connected;
3092		/* for logical ports - cache the EDID */
3093		if (port->port_num >= 8 && !port->cached_edid) {
3094			port->cached_edid = drm_get_edid(connector, &port->aux.ddc);
3095		}
3096		break;
3097	case DP_PEER_DEVICE_DP_LEGACY_CONV:
3098		if (port->ldps)
3099			status = connector_status_connected;
3100		break;
3101	}
3102out:
3103	drm_dp_mst_topology_put_port(port);
3104	return status;
3105}
3106EXPORT_SYMBOL(drm_dp_mst_detect_port);
3107
3108/**
3109 * drm_dp_mst_port_has_audio() - Check whether port has audio capability or not
3110 * @mgr: manager for this port
3111 * @port: unverified pointer to a port.
3112 *
3113 * This returns whether the port supports audio or not.
3114 */
3115bool drm_dp_mst_port_has_audio(struct drm_dp_mst_topology_mgr *mgr,
3116					struct drm_dp_mst_port *port)
3117{
3118	bool ret = false;
3119
3120	port = drm_dp_mst_topology_get_port_validated(mgr, port);
3121	if (!port)
3122		return ret;
3123	ret = port->has_audio;
3124	drm_dp_mst_topology_put_port(port);
3125	return ret;
3126}
3127EXPORT_SYMBOL(drm_dp_mst_port_has_audio);
3128
3129/**
3130 * drm_dp_mst_get_edid() - get EDID for an MST port
3131 * @connector: toplevel connector to get EDID for
3132 * @mgr: manager for this port
3133 * @port: unverified pointer to a port.
3134 *
3135 * This returns an EDID for the port connected to a connector,
3136 * It validates the pointer still exists so the caller doesn't require a
3137 * reference.
3138 */
3139struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
3140{
3141	struct edid *edid = NULL;
3142
3143	/* we need to search for the port in the mgr in case it's gone */
3144	port = drm_dp_mst_topology_get_port_validated(mgr, port);
3145	if (!port)
3146		return NULL;
3147
3148	if (port->cached_edid)
3149		edid = drm_edid_duplicate(port->cached_edid);
3150	else {
3151		edid = drm_get_edid(connector, &port->aux.ddc);
 
3152	}
3153	port->has_audio = drm_detect_monitor_audio(edid);
3154	drm_dp_mst_topology_put_port(port);
3155	return edid;
3156}
3157EXPORT_SYMBOL(drm_dp_mst_get_edid);
3158
3159/**
3160 * drm_dp_find_vcpi_slots() - Find VCPI slots for this PBN value
3161 * @mgr: manager to use
3162 * @pbn: payload bandwidth to convert into slots.
3163 *
3164 * Calculate the number of VCPI slots that will be required for the given PBN
3165 * value. This function is deprecated, and should not be used in atomic
3166 * drivers.
3167 *
3168 * RETURNS:
3169 * The total slots required for this port, or error.
3170 */
3171int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
3172			   int pbn)
3173{
3174	int num_slots;
3175
3176	num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
3177
3178	/* max. time slots - one slot for MTP header */
3179	if (num_slots > 63)
3180		return -ENOSPC;
3181	return num_slots;
3182}
3183EXPORT_SYMBOL(drm_dp_find_vcpi_slots);
3184
3185static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
3186			    struct drm_dp_vcpi *vcpi, int pbn, int slots)
3187{
3188	int ret;
3189
3190	/* max. time slots - one slot for MTP header */
3191	if (slots > 63)
3192		return -ENOSPC;
3193
3194	vcpi->pbn = pbn;
3195	vcpi->aligned_pbn = slots * mgr->pbn_div;
3196	vcpi->num_slots = slots;
3197
3198	ret = drm_dp_mst_assign_payload_id(mgr, vcpi);
3199	if (ret < 0)
3200		return ret;
3201	return 0;
3202}
3203
3204/**
3205 * drm_dp_atomic_find_vcpi_slots() - Find and add VCPI slots to the state
3206 * @state: global atomic state
3207 * @mgr: MST topology manager for the port
3208 * @port: port to find vcpi slots for
3209 * @pbn: bandwidth required for the mode in PBN
3210 *
3211 * Allocates VCPI slots to @port, replacing any previous VCPI allocations it
3212 * may have had. Any atomic drivers which support MST must call this function
3213 * in their &drm_encoder_helper_funcs.atomic_check() callback to change the
3214 * current VCPI allocation for the new state, but only when
3215 * &drm_crtc_state.mode_changed or &drm_crtc_state.connectors_changed is set
3216 * to ensure compatibility with userspace applications that still use the
3217 * legacy modesetting UAPI.
3218 *
3219 * Allocations set by this function are not checked against the bandwidth
3220 * restraints of @mgr until the driver calls drm_dp_mst_atomic_check().
3221 *
3222 * Additionally, it is OK to call this function multiple times on the same
3223 * @port as needed. It is not OK however, to call this function and
3224 * drm_dp_atomic_release_vcpi_slots() in the same atomic check phase.
3225 *
3226 * See also:
3227 * drm_dp_atomic_release_vcpi_slots()
3228 * drm_dp_mst_atomic_check()
3229 *
3230 * Returns:
3231 * Total slots in the atomic state assigned for this port, or a negative error
3232 * code if the port no longer exists
3233 */
3234int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
3235				  struct drm_dp_mst_topology_mgr *mgr,
3236				  struct drm_dp_mst_port *port, int pbn)
3237{
3238	struct drm_dp_mst_topology_state *topology_state;
3239	struct drm_dp_vcpi_allocation *pos, *vcpi = NULL;
3240	int prev_slots, req_slots, ret;
3241
3242	topology_state = drm_atomic_get_mst_topology_state(state, mgr);
3243	if (IS_ERR(topology_state))
3244		return PTR_ERR(topology_state);
3245
3246	/* Find the current allocation for this port, if any */
3247	list_for_each_entry(pos, &topology_state->vcpis, next) {
3248		if (pos->port == port) {
3249			vcpi = pos;
3250			prev_slots = vcpi->vcpi;
3251
3252			/*
3253			 * This should never happen, unless the driver tries
3254			 * releasing and allocating the same VCPI allocation,
3255			 * which is an error
3256			 */
3257			if (WARN_ON(!prev_slots)) {
3258				DRM_ERROR("cannot allocate and release VCPI on [MST PORT:%p] in the same state\n",
3259					  port);
3260				return -EINVAL;
3261			}
3262
3263			break;
3264		}
3265	}
3266	if (!vcpi)
3267		prev_slots = 0;
3268
3269	req_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
 
 
3270
3271	DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] [MST PORT:%p] VCPI %d -> %d\n",
3272			 port->connector->base.id, port->connector->name,
3273			 port, prev_slots, req_slots);
3274
3275	/* Add the new allocation to the state */
3276	if (!vcpi) {
3277		vcpi = kzalloc(sizeof(*vcpi), GFP_KERNEL);
3278		if (!vcpi)
3279			return -ENOMEM;
3280
3281		drm_dp_mst_get_port_malloc(port);
3282		vcpi->port = port;
3283		list_add(&vcpi->next, &topology_state->vcpis);
3284	}
3285	vcpi->vcpi = req_slots;
3286
3287	ret = req_slots;
3288	return ret;
 
 
 
3289}
3290EXPORT_SYMBOL(drm_dp_atomic_find_vcpi_slots);
3291
3292/**
3293 * drm_dp_atomic_release_vcpi_slots() - Release allocated vcpi slots
3294 * @state: global atomic state
3295 * @mgr: MST topology manager for the port
3296 * @port: The port to release the VCPI slots from
3297 *
3298 * Releases any VCPI slots that have been allocated to a port in the atomic
3299 * state. Any atomic drivers which support MST must call this function in
3300 * their &drm_connector_helper_funcs.atomic_check() callback when the
3301 * connector will no longer have VCPI allocated (e.g. because its CRTC was
3302 * removed) when it had VCPI allocated in the previous atomic state.
3303 *
3304 * It is OK to call this even if @port has been removed from the system.
3305 * Additionally, it is OK to call this function multiple times on the same
3306 * @port as needed. It is not OK however, to call this function and
3307 * drm_dp_atomic_find_vcpi_slots() on the same @port in a single atomic check
3308 * phase.
3309 *
3310 * See also:
3311 * drm_dp_atomic_find_vcpi_slots()
3312 * drm_dp_mst_atomic_check()
3313 *
3314 * Returns:
3315 * 0 if all slots for this port were added back to
3316 * &drm_dp_mst_topology_state.avail_slots or negative error code
3317 */
3318int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
3319				     struct drm_dp_mst_topology_mgr *mgr,
3320				     struct drm_dp_mst_port *port)
3321{
3322	struct drm_dp_mst_topology_state *topology_state;
3323	struct drm_dp_vcpi_allocation *pos;
3324	bool found = false;
3325
3326	topology_state = drm_atomic_get_mst_topology_state(state, mgr);
3327	if (IS_ERR(topology_state))
3328		return PTR_ERR(topology_state);
3329
3330	list_for_each_entry(pos, &topology_state->vcpis, next) {
3331		if (pos->port == port) {
3332			found = true;
3333			break;
3334		}
3335	}
3336	if (WARN_ON(!found)) {
3337		DRM_ERROR("no VCPI for [MST PORT:%p] found in mst state %p\n",
3338			  port, &topology_state->base);
3339		return -EINVAL;
3340	}
3341
3342	DRM_DEBUG_ATOMIC("[MST PORT:%p] VCPI %d -> 0\n", port, pos->vcpi);
3343	if (pos->vcpi) {
3344		drm_dp_mst_put_port_malloc(port);
3345		pos->vcpi = 0;
3346	}
3347
3348	return 0;
3349}
3350EXPORT_SYMBOL(drm_dp_atomic_release_vcpi_slots);
3351
3352/**
3353 * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
3354 * @mgr: manager for this port
3355 * @port: port to allocate a virtual channel for.
3356 * @pbn: payload bandwidth number to request
3357 * @slots: returned number of slots for this PBN.
3358 */
3359bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
3360			      struct drm_dp_mst_port *port, int pbn, int slots)
3361{
3362	int ret;
3363
3364	port = drm_dp_mst_topology_get_port_validated(mgr, port);
3365	if (!port)
3366		return false;
3367
3368	if (slots < 0)
3369		return false;
3370
3371	if (port->vcpi.vcpi > 0) {
3372		DRM_DEBUG_KMS("payload: vcpi %d already allocated for pbn %d - requested pbn %d\n",
3373			      port->vcpi.vcpi, port->vcpi.pbn, pbn);
3374		if (pbn == port->vcpi.pbn) {
3375			drm_dp_mst_topology_put_port(port);
3376			return true;
3377		}
3378	}
3379
3380	ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn, slots);
3381	if (ret) {
3382		DRM_DEBUG_KMS("failed to init vcpi slots=%d max=63 ret=%d\n",
3383			      DIV_ROUND_UP(pbn, mgr->pbn_div), ret);
3384		goto out;
3385	}
3386	DRM_DEBUG_KMS("initing vcpi for pbn=%d slots=%d\n",
3387		      pbn, port->vcpi.num_slots);
3388
3389	/* Keep port allocated until its payload has been removed */
3390	drm_dp_mst_get_port_malloc(port);
3391	drm_dp_mst_topology_put_port(port);
3392	return true;
3393out:
3394	return false;
3395}
3396EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
3397
3398int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
3399{
3400	int slots = 0;
3401	port = drm_dp_mst_topology_get_port_validated(mgr, port);
3402	if (!port)
3403		return slots;
3404
3405	slots = port->vcpi.num_slots;
3406	drm_dp_mst_topology_put_port(port);
3407	return slots;
3408}
3409EXPORT_SYMBOL(drm_dp_mst_get_vcpi_slots);
3410
3411/**
3412 * drm_dp_mst_reset_vcpi_slots() - Reset number of slots to 0 for VCPI
3413 * @mgr: manager for this port
3414 * @port: unverified pointer to a port.
3415 *
3416 * This just resets the number of slots for the ports VCPI for later programming.
3417 */
3418void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
3419{
3420	/*
3421	 * A port with VCPI will remain allocated until its VCPI is
3422	 * released, no verified ref needed
3423	 */
3424
3425	port->vcpi.num_slots = 0;
 
3426}
3427EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
3428
3429/**
3430 * drm_dp_mst_deallocate_vcpi() - deallocate a VCPI
3431 * @mgr: manager for this port
3432 * @port: port to deallocate vcpi for
3433 *
3434 * This can be called unconditionally, regardless of whether
3435 * drm_dp_mst_allocate_vcpi() succeeded or not.
3436 */
3437void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
3438				struct drm_dp_mst_port *port)
3439{
3440	if (!port->vcpi.vcpi)
 
3441		return;
3442
3443	drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
3444	port->vcpi.num_slots = 0;
3445	port->vcpi.pbn = 0;
3446	port->vcpi.aligned_pbn = 0;
3447	port->vcpi.vcpi = 0;
3448	drm_dp_mst_put_port_malloc(port);
3449}
3450EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
3451
3452static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
3453				     int id, struct drm_dp_payload *payload)
3454{
3455	u8 payload_alloc[3], status;
3456	int ret;
3457	int retries = 0;
3458
3459	drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
3460			   DP_PAYLOAD_TABLE_UPDATED);
3461
3462	payload_alloc[0] = id;
3463	payload_alloc[1] = payload->start_slot;
3464	payload_alloc[2] = payload->num_slots;
3465
3466	ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
3467	if (ret != 3) {
3468		DRM_DEBUG_KMS("failed to write payload allocation %d\n", ret);
3469		goto fail;
3470	}
3471
3472retry:
3473	ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
3474	if (ret < 0) {
3475		DRM_DEBUG_KMS("failed to read payload table status %d\n", ret);
3476		goto fail;
3477	}
3478
3479	if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
3480		retries++;
3481		if (retries < 20) {
3482			usleep_range(10000, 20000);
3483			goto retry;
3484		}
3485		DRM_DEBUG_KMS("status not set after read payload table status %d\n", status);
3486		ret = -EINVAL;
3487		goto fail;
3488	}
3489	ret = 0;
3490fail:
3491	return ret;
3492}
3493
3494
3495/**
3496 * drm_dp_check_act_status() - Check ACT handled status.
3497 * @mgr: manager to use
3498 *
3499 * Check the payload status bits in the DPCD for ACT handled completion.
3500 */
3501int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
3502{
3503	u8 status;
3504	int ret;
3505	int count = 0;
3506
3507	do {
3508		ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
3509
3510		if (ret < 0) {
3511			DRM_DEBUG_KMS("failed to read payload table status %d\n", ret);
3512			goto fail;
3513		}
3514
3515		if (status & DP_PAYLOAD_ACT_HANDLED)
3516			break;
3517		count++;
3518		udelay(100);
3519
3520	} while (count < 30);
3521
3522	if (!(status & DP_PAYLOAD_ACT_HANDLED)) {
3523		DRM_DEBUG_KMS("failed to get ACT bit %d after %d retries\n", status, count);
3524		ret = -EINVAL;
3525		goto fail;
3526	}
3527	return 0;
3528fail:
3529	return ret;
3530}
3531EXPORT_SYMBOL(drm_dp_check_act_status);
3532
3533/**
3534 * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
3535 * @clock: dot clock for the mode
3536 * @bpp: bpp for the mode.
3537 *
3538 * This uses the formula in the spec to calculate the PBN value for a mode.
3539 */
3540int drm_dp_calc_pbn_mode(int clock, int bpp)
3541{
3542	u64 kbps;
3543	s64 peak_kbps;
3544	u32 numerator;
3545	u32 denominator;
3546
3547	kbps = clock * bpp;
3548
3549	/*
3550	 * margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006
3551	 * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on
3552	 * common multiplier to render an integer PBN for all link rate/lane
3553	 * counts combinations
3554	 * calculate
3555	 * peak_kbps *= (1006/1000)
3556	 * peak_kbps *= (64/54)
3557	 * peak_kbps *= 8    convert to bytes
3558	 */
3559
3560	numerator = 64 * 1006;
3561	denominator = 54 * 8 * 1000 * 1000;
3562
3563	kbps *= numerator;
3564	peak_kbps = drm_fixp_from_fraction(kbps, denominator);
3565
3566	return drm_fixp2int_ceil(peak_kbps);
3567}
3568EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
3569
3570static int test_calc_pbn_mode(void)
3571{
3572	int ret;
3573	ret = drm_dp_calc_pbn_mode(154000, 30);
3574	if (ret != 689) {
3575		DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n",
3576				154000, 30, 689, ret);
3577		return -EINVAL;
3578	}
3579	ret = drm_dp_calc_pbn_mode(234000, 30);
3580	if (ret != 1047) {
3581		DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n",
3582				234000, 30, 1047, ret);
3583		return -EINVAL;
3584	}
3585	ret = drm_dp_calc_pbn_mode(297000, 24);
3586	if (ret != 1063) {
3587		DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n",
3588				297000, 24, 1063, ret);
3589		return -EINVAL;
3590	}
3591	return 0;
3592}
3593
3594/* we want to kick the TX after we've ack the up/down IRQs. */
3595static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
3596{
3597	queue_work(system_long_wq, &mgr->tx_work);
3598}
3599
3600static void drm_dp_mst_dump_mstb(struct seq_file *m,
3601				 struct drm_dp_mst_branch *mstb)
3602{
3603	struct drm_dp_mst_port *port;
3604	int tabs = mstb->lct;
3605	char prefix[10];
3606	int i;
3607
3608	for (i = 0; i < tabs; i++)
3609		prefix[i] = '\t';
3610	prefix[i] = '\0';
3611
3612	seq_printf(m, "%smst: %p, %d\n", prefix, mstb, mstb->num_ports);
3613	list_for_each_entry(port, &mstb->ports, next) {
3614		seq_printf(m, "%sport: %d: input: %d: pdt: %d, ddps: %d ldps: %d, sdp: %d/%d, %p, conn: %p\n", prefix, port->port_num, port->input, port->pdt, port->ddps, port->ldps, port->num_sdp_streams, port->num_sdp_stream_sinks, port, port->connector);
3615		if (port->mstb)
3616			drm_dp_mst_dump_mstb(m, port->mstb);
3617	}
3618}
3619
3620#define DP_PAYLOAD_TABLE_SIZE		64
3621
3622static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
3623				  char *buf)
3624{
3625	int i;
3626
3627	for (i = 0; i < DP_PAYLOAD_TABLE_SIZE; i += 16) {
3628		if (drm_dp_dpcd_read(mgr->aux,
3629				     DP_PAYLOAD_TABLE_UPDATE_STATUS + i,
3630				     &buf[i], 16) != 16)
3631			return false;
3632	}
3633	return true;
3634}
3635
3636static void fetch_monitor_name(struct drm_dp_mst_topology_mgr *mgr,
3637			       struct drm_dp_mst_port *port, char *name,
3638			       int namelen)
3639{
3640	struct edid *mst_edid;
3641
3642	mst_edid = drm_dp_mst_get_edid(port->connector, mgr, port);
3643	drm_edid_get_monitor_name(mst_edid, name, namelen);
3644}
3645
3646/**
3647 * drm_dp_mst_dump_topology(): dump topology to seq file.
3648 * @m: seq_file to dump output to
3649 * @mgr: manager to dump current topology for.
3650 *
3651 * helper to dump MST topology to a seq file for debugfs.
3652 */
3653void drm_dp_mst_dump_topology(struct seq_file *m,
3654			      struct drm_dp_mst_topology_mgr *mgr)
3655{
3656	int i;
3657	struct drm_dp_mst_port *port;
3658
3659	mutex_lock(&mgr->lock);
3660	if (mgr->mst_primary)
3661		drm_dp_mst_dump_mstb(m, mgr->mst_primary);
3662
3663	/* dump VCPIs */
3664	mutex_unlock(&mgr->lock);
3665
3666	mutex_lock(&mgr->payload_lock);
3667	seq_printf(m, "vcpi: %lx %lx %d\n", mgr->payload_mask, mgr->vcpi_mask,
3668		mgr->max_payloads);
3669
3670	for (i = 0; i < mgr->max_payloads; i++) {
3671		if (mgr->proposed_vcpis[i]) {
3672			char name[14];
3673
3674			port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
3675			fetch_monitor_name(mgr, port, name, sizeof(name));
3676			seq_printf(m, "vcpi %d: %d %d %d sink name: %s\n", i,
3677				   port->port_num, port->vcpi.vcpi,
3678				   port->vcpi.num_slots,
3679				   (*name != 0) ? name :  "Unknown");
3680		} else
3681			seq_printf(m, "vcpi %d:unused\n", i);
3682	}
3683	for (i = 0; i < mgr->max_payloads; i++) {
3684		seq_printf(m, "payload %d: %d, %d, %d\n",
3685			   i,
3686			   mgr->payloads[i].payload_state,
3687			   mgr->payloads[i].start_slot,
3688			   mgr->payloads[i].num_slots);
3689
3690
3691	}
3692	mutex_unlock(&mgr->payload_lock);
3693
3694	mutex_lock(&mgr->lock);
3695	if (mgr->mst_primary) {
3696		u8 buf[DP_PAYLOAD_TABLE_SIZE];
3697		int ret;
3698
3699		ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, buf, DP_RECEIVER_CAP_SIZE);
3700		seq_printf(m, "dpcd: %*ph\n", DP_RECEIVER_CAP_SIZE, buf);
3701		ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
3702		seq_printf(m, "faux/mst: %*ph\n", 2, buf);
3703		ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
3704		seq_printf(m, "mst ctrl: %*ph\n", 1, buf);
3705
3706		/* dump the standard OUI branch header */
3707		ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
3708		seq_printf(m, "branch oui: %*phN devid: ", 3, buf);
3709		for (i = 0x3; i < 0x8 && buf[i]; i++)
3710			seq_printf(m, "%c", buf[i]);
3711		seq_printf(m, " revision: hw: %x.%x sw: %x.%x\n",
3712			   buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]);
3713		if (dump_dp_payload_table(mgr, buf))
3714			seq_printf(m, "payload table: %*ph\n", DP_PAYLOAD_TABLE_SIZE, buf);
 
3715	}
3716
3717	mutex_unlock(&mgr->lock);
3718
3719}
3720EXPORT_SYMBOL(drm_dp_mst_dump_topology);
3721
3722static void drm_dp_tx_work(struct work_struct *work)
3723{
3724	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
3725
3726	mutex_lock(&mgr->qlock);
3727	if (!list_empty(&mgr->tx_msg_downq))
3728		process_single_down_tx_qlock(mgr);
3729	mutex_unlock(&mgr->qlock);
3730}
3731
 
 
 
 
 
 
 
3732static void drm_dp_destroy_connector_work(struct work_struct *work)
3733{
3734	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, destroy_connector_work);
3735	struct drm_dp_mst_port *port;
3736	bool send_hotplug = false;
3737	/*
3738	 * Not a regular list traverse as we have to drop the destroy
3739	 * connector lock before destroying the connector, to avoid AB->BA
3740	 * ordering between this lock and the config mutex.
3741	 */
3742	for (;;) {
3743		mutex_lock(&mgr->destroy_connector_lock);
3744		port = list_first_entry_or_null(&mgr->destroy_connector_list, struct drm_dp_mst_port, next);
3745		if (!port) {
3746			mutex_unlock(&mgr->destroy_connector_lock);
3747			break;
3748		}
3749		list_del(&port->next);
3750		mutex_unlock(&mgr->destroy_connector_lock);
3751
 
3752		INIT_LIST_HEAD(&port->next);
3753
3754		mgr->cbs->destroy_connector(mgr, port->connector);
3755
3756		drm_dp_port_teardown_pdt(port, port->pdt);
3757		port->pdt = DP_PEER_DEVICE_NONE;
3758
3759		drm_dp_mst_put_port_malloc(port);
 
 
 
 
 
 
3760		send_hotplug = true;
3761	}
3762	if (send_hotplug)
3763		drm_kms_helper_hotplug_event(mgr->dev);
3764}
3765
3766static struct drm_private_state *
3767drm_dp_mst_duplicate_state(struct drm_private_obj *obj)
3768{
3769	struct drm_dp_mst_topology_state *state, *old_state =
3770		to_dp_mst_topology_state(obj->state);
3771	struct drm_dp_vcpi_allocation *pos, *vcpi;
3772
3773	state = kmemdup(old_state, sizeof(*state), GFP_KERNEL);
3774	if (!state)
3775		return NULL;
3776
3777	__drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
3778
3779	INIT_LIST_HEAD(&state->vcpis);
3780
3781	list_for_each_entry(pos, &old_state->vcpis, next) {
3782		/* Prune leftover freed VCPI allocations */
3783		if (!pos->vcpi)
3784			continue;
3785
3786		vcpi = kmemdup(pos, sizeof(*vcpi), GFP_KERNEL);
3787		if (!vcpi)
3788			goto fail;
3789
3790		drm_dp_mst_get_port_malloc(vcpi->port);
3791		list_add(&vcpi->next, &state->vcpis);
3792	}
3793
3794	return &state->base;
3795
3796fail:
3797	list_for_each_entry_safe(pos, vcpi, &state->vcpis, next) {
3798		drm_dp_mst_put_port_malloc(pos->port);
3799		kfree(pos);
3800	}
3801	kfree(state);
3802
3803	return NULL;
3804}
3805
3806static void drm_dp_mst_destroy_state(struct drm_private_obj *obj,
3807				     struct drm_private_state *state)
3808{
3809	struct drm_dp_mst_topology_state *mst_state =
3810		to_dp_mst_topology_state(state);
3811	struct drm_dp_vcpi_allocation *pos, *tmp;
3812
3813	list_for_each_entry_safe(pos, tmp, &mst_state->vcpis, next) {
3814		/* We only keep references to ports with non-zero VCPIs */
3815		if (pos->vcpi)
3816			drm_dp_mst_put_port_malloc(pos->port);
3817		kfree(pos);
3818	}
3819
3820	kfree(mst_state);
3821}
3822
3823static inline int
3824drm_dp_mst_atomic_check_topology_state(struct drm_dp_mst_topology_mgr *mgr,
3825				       struct drm_dp_mst_topology_state *mst_state)
3826{
3827	struct drm_dp_vcpi_allocation *vcpi;
3828	int avail_slots = 63, payload_count = 0;
3829
3830	list_for_each_entry(vcpi, &mst_state->vcpis, next) {
3831		/* Releasing VCPI is always OK-even if the port is gone */
3832		if (!vcpi->vcpi) {
3833			DRM_DEBUG_ATOMIC("[MST PORT:%p] releases all VCPI slots\n",
3834					 vcpi->port);
3835			continue;
3836		}
3837
3838		DRM_DEBUG_ATOMIC("[MST PORT:%p] requires %d vcpi slots\n",
3839				 vcpi->port, vcpi->vcpi);
3840
3841		avail_slots -= vcpi->vcpi;
3842		if (avail_slots < 0) {
3843			DRM_DEBUG_ATOMIC("[MST PORT:%p] not enough VCPI slots in mst state %p (avail=%d)\n",
3844					 vcpi->port, mst_state,
3845					 avail_slots + vcpi->vcpi);
3846			return -ENOSPC;
3847		}
3848
3849		if (++payload_count > mgr->max_payloads) {
3850			DRM_DEBUG_ATOMIC("[MST MGR:%p] state %p has too many payloads (max=%d)\n",
3851					 mgr, mst_state, mgr->max_payloads);
3852			return -EINVAL;
3853		}
3854	}
3855	DRM_DEBUG_ATOMIC("[MST MGR:%p] mst state %p VCPI avail=%d used=%d\n",
3856			 mgr, mst_state, avail_slots,
3857			 63 - avail_slots);
3858
3859	return 0;
3860}
3861
3862/**
3863 * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
3864 * atomic update is valid
3865 * @state: Pointer to the new &struct drm_dp_mst_topology_state
3866 *
3867 * Checks the given topology state for an atomic update to ensure that it's
3868 * valid. This includes checking whether there's enough bandwidth to support
3869 * the new VCPI allocations in the atomic update.
3870 *
3871 * Any atomic drivers supporting DP MST must make sure to call this after
3872 * checking the rest of their state in their
3873 * &drm_mode_config_funcs.atomic_check() callback.
3874 *
3875 * See also:
3876 * drm_dp_atomic_find_vcpi_slots()
3877 * drm_dp_atomic_release_vcpi_slots()
3878 *
3879 * Returns:
3880 *
3881 * 0 if the new state is valid, negative error code otherwise.
3882 */
3883int drm_dp_mst_atomic_check(struct drm_atomic_state *state)
3884{
3885	struct drm_dp_mst_topology_mgr *mgr;
3886	struct drm_dp_mst_topology_state *mst_state;
3887	int i, ret = 0;
3888
3889	for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
3890		ret = drm_dp_mst_atomic_check_topology_state(mgr, mst_state);
3891		if (ret)
3892			break;
3893	}
3894
3895	return ret;
3896}
3897EXPORT_SYMBOL(drm_dp_mst_atomic_check);
3898
3899const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs = {
3900	.atomic_duplicate_state = drm_dp_mst_duplicate_state,
3901	.atomic_destroy_state = drm_dp_mst_destroy_state,
3902};
3903EXPORT_SYMBOL(drm_dp_mst_topology_state_funcs);
3904
3905/**
3906 * drm_atomic_get_mst_topology_state: get MST topology state
3907 *
3908 * @state: global atomic state
3909 * @mgr: MST topology manager, also the private object in this case
3910 *
3911 * This function wraps drm_atomic_get_priv_obj_state() passing in the MST atomic
3912 * state vtable so that the private object state returned is that of a MST
3913 * topology object. Also, drm_atomic_get_private_obj_state() expects the caller
3914 * to care of the locking, so warn if don't hold the connection_mutex.
3915 *
3916 * RETURNS:
3917 *
3918 * The MST topology state or error pointer.
3919 */
3920struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
3921								    struct drm_dp_mst_topology_mgr *mgr)
3922{
3923	struct drm_device *dev = mgr->dev;
3924
3925	WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
3926	return to_dp_mst_topology_state(drm_atomic_get_private_obj_state(state, &mgr->base));
3927}
3928EXPORT_SYMBOL(drm_atomic_get_mst_topology_state);
3929
3930/**
3931 * drm_dp_mst_topology_mgr_init - initialise a topology manager
3932 * @mgr: manager struct to initialise
3933 * @dev: device providing this structure - for i2c addition.
3934 * @aux: DP helper aux channel to talk to this device
3935 * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
3936 * @max_payloads: maximum number of payloads this GPU can source
3937 * @conn_base_id: the connector object ID the MST device is connected to.
3938 *
3939 * Return 0 for success, or negative error code on failure
3940 */
3941int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
3942				 struct drm_device *dev, struct drm_dp_aux *aux,
3943				 int max_dpcd_transaction_bytes,
3944				 int max_payloads, int conn_base_id)
3945{
3946	struct drm_dp_mst_topology_state *mst_state;
3947
3948	mutex_init(&mgr->lock);
3949	mutex_init(&mgr->qlock);
3950	mutex_init(&mgr->payload_lock);
3951	mutex_init(&mgr->destroy_connector_lock);
3952	INIT_LIST_HEAD(&mgr->tx_msg_downq);
3953	INIT_LIST_HEAD(&mgr->destroy_connector_list);
3954	INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
3955	INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
3956	INIT_WORK(&mgr->destroy_connector_work, drm_dp_destroy_connector_work);
3957	init_waitqueue_head(&mgr->tx_waitq);
3958	mgr->dev = dev;
3959	mgr->aux = aux;
3960	mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
3961	mgr->max_payloads = max_payloads;
3962	mgr->conn_base_id = conn_base_id;
3963	if (max_payloads + 1 > sizeof(mgr->payload_mask) * 8 ||
3964	    max_payloads + 1 > sizeof(mgr->vcpi_mask) * 8)
3965		return -EINVAL;
3966	mgr->payloads = kcalloc(max_payloads, sizeof(struct drm_dp_payload), GFP_KERNEL);
3967	if (!mgr->payloads)
3968		return -ENOMEM;
3969	mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);
3970	if (!mgr->proposed_vcpis)
3971		return -ENOMEM;
3972	set_bit(0, &mgr->payload_mask);
3973	if (test_calc_pbn_mode() < 0)
3974		DRM_ERROR("MST PBN self-test failed\n");
3975
3976	mst_state = kzalloc(sizeof(*mst_state), GFP_KERNEL);
3977	if (mst_state == NULL)
3978		return -ENOMEM;
3979
3980	mst_state->mgr = mgr;
3981	INIT_LIST_HEAD(&mst_state->vcpis);
3982
3983	drm_atomic_private_obj_init(dev, &mgr->base,
 
 
 
3984				    &mst_state->base,
3985				    &drm_dp_mst_topology_state_funcs);
3986
3987	return 0;
3988}
3989EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
3990
3991/**
3992 * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
3993 * @mgr: manager to destroy
3994 */
3995void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
3996{
3997	drm_dp_mst_topology_mgr_set_mst(mgr, false);
3998	flush_work(&mgr->work);
3999	flush_work(&mgr->destroy_connector_work);
4000	mutex_lock(&mgr->payload_lock);
4001	kfree(mgr->payloads);
4002	mgr->payloads = NULL;
4003	kfree(mgr->proposed_vcpis);
4004	mgr->proposed_vcpis = NULL;
4005	mutex_unlock(&mgr->payload_lock);
4006	mgr->dev = NULL;
4007	mgr->aux = NULL;
4008	drm_atomic_private_obj_fini(&mgr->base);
4009	mgr->funcs = NULL;
4010}
4011EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
4012
4013static bool remote_i2c_read_ok(const struct i2c_msg msgs[], int num)
4014{
4015	int i;
4016
4017	if (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)
4018		return false;
4019
4020	for (i = 0; i < num - 1; i++) {
4021		if (msgs[i].flags & I2C_M_RD ||
4022		    msgs[i].len > 0xff)
4023			return false;
4024	}
4025
4026	return msgs[num - 1].flags & I2C_M_RD &&
4027		msgs[num - 1].len <= 0xff;
4028}
4029
4030/* I2C device */
4031static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
4032			       int num)
4033{
4034	struct drm_dp_aux *aux = adapter->algo_data;
4035	struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port, aux);
4036	struct drm_dp_mst_branch *mstb;
4037	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
4038	unsigned int i;
 
4039	struct drm_dp_sideband_msg_req_body msg;
4040	struct drm_dp_sideband_msg_tx *txmsg = NULL;
4041	int ret;
4042
4043	mstb = drm_dp_mst_topology_get_mstb_validated(mgr, port->parent);
4044	if (!mstb)
4045		return -EREMOTEIO;
4046
4047	if (!remote_i2c_read_ok(msgs, num)) {
 
 
 
 
 
4048		DRM_DEBUG_KMS("Unsupported I2C transaction for MST device\n");
4049		ret = -EIO;
4050		goto out;
4051	}
4052
4053	memset(&msg, 0, sizeof(msg));
4054	msg.req_type = DP_REMOTE_I2C_READ;
4055	msg.u.i2c_read.num_transactions = num - 1;
4056	msg.u.i2c_read.port_number = port->port_num;
4057	for (i = 0; i < num - 1; i++) {
4058		msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
4059		msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
4060		msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
4061		msg.u.i2c_read.transactions[i].no_stop_bit = !(msgs[i].flags & I2C_M_STOP);
4062	}
4063	msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
4064	msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
4065
4066	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
4067	if (!txmsg) {
4068		ret = -ENOMEM;
4069		goto out;
4070	}
4071
4072	txmsg->dst = mstb;
4073	drm_dp_encode_sideband_req(&msg, txmsg);
4074
4075	drm_dp_queue_down_tx(mgr, txmsg);
4076
4077	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
4078	if (ret > 0) {
4079
4080		if (txmsg->reply.reply_type == DP_SIDEBAND_REPLY_NAK) {
4081			ret = -EREMOTEIO;
4082			goto out;
4083		}
4084		if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
4085			ret = -EIO;
4086			goto out;
4087		}
4088		memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
4089		ret = num;
4090	}
4091out:
4092	kfree(txmsg);
4093	drm_dp_mst_topology_put_mstb(mstb);
4094	return ret;
4095}
4096
4097static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
4098{
4099	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
4100	       I2C_FUNC_SMBUS_READ_BLOCK_DATA |
4101	       I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
4102	       I2C_FUNC_10BIT_ADDR;
4103}
4104
4105static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
4106	.functionality = drm_dp_mst_i2c_functionality,
4107	.master_xfer = drm_dp_mst_i2c_xfer,
4108};
4109
4110/**
4111 * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
4112 * @aux: DisplayPort AUX channel
4113 *
4114 * Returns 0 on success or a negative error code on failure.
4115 */
4116static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux)
4117{
4118	aux->ddc.algo = &drm_dp_mst_i2c_algo;
4119	aux->ddc.algo_data = aux;
4120	aux->ddc.retries = 3;
4121
4122	aux->ddc.class = I2C_CLASS_DDC;
4123	aux->ddc.owner = THIS_MODULE;
4124	aux->ddc.dev.parent = aux->dev;
4125	aux->ddc.dev.of_node = aux->dev->of_node;
4126
4127	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
4128		sizeof(aux->ddc.name));
4129
4130	return i2c_add_adapter(&aux->ddc);
4131}
4132
4133/**
4134 * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
4135 * @aux: DisplayPort AUX channel
4136 */
4137static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_aux *aux)
4138{
4139	i2c_del_adapter(&aux->ddc);
4140}