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/kernel.h>
  24#include <linux/delay.h>
  25#include <linux/init.h>
  26#include <linux/errno.h>
  27#include <linux/sched.h>
  28#include <linux/seq_file.h>
  29#include <linux/i2c.h>
  30#include <drm/drm_dp_mst_helper.h>
  31#include <drm/drmP.h>
  32
  33#include <drm/drm_fixed.h>
  34
  35/**
  36 * DOC: dp mst helper
  37 *
  38 * These functions contain parts of the DisplayPort 1.2a MultiStream Transport
  39 * protocol. The helpers contain a topology manager and bandwidth manager.
  40 * The helpers encapsulate the sending and received of sideband msgs.
  41 */
  42static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
  43				  char *buf);
  44static int test_calc_pbn_mode(void);
  45
  46static void drm_dp_put_port(struct drm_dp_mst_port *port);
  47
  48static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
  49				     int id,
  50				     struct drm_dp_payload *payload);
  51
  52static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
  53				  struct drm_dp_mst_port *port,
  54				  int offset, int size, u8 *bytes);
  55
  56static void drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
  57				     struct drm_dp_mst_branch *mstb);
  58static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
  59					   struct drm_dp_mst_branch *mstb,
  60					   struct drm_dp_mst_port *port);
  61static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
  62				 u8 *guid);
  63
  64static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux);
  65static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_aux *aux);
  66static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
  67/* sideband msg handling */
  68static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
  69{
  70	u8 bitmask = 0x80;
  71	u8 bitshift = 7;
  72	u8 array_index = 0;
  73	int number_of_bits = num_nibbles * 4;
  74	u8 remainder = 0;
  75
  76	while (number_of_bits != 0) {
  77		number_of_bits--;
  78		remainder <<= 1;
  79		remainder |= (data[array_index] & bitmask) >> bitshift;
  80		bitmask >>= 1;
  81		bitshift--;
  82		if (bitmask == 0) {
  83			bitmask = 0x80;
  84			bitshift = 7;
  85			array_index++;
  86		}
  87		if ((remainder & 0x10) == 0x10)
  88			remainder ^= 0x13;
  89	}
  90
  91	number_of_bits = 4;
  92	while (number_of_bits != 0) {
  93		number_of_bits--;
  94		remainder <<= 1;
  95		if ((remainder & 0x10) != 0)
  96			remainder ^= 0x13;
  97	}
  98
  99	return remainder;
 100}
 101
 102static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes)
 103{
 104	u8 bitmask = 0x80;
 105	u8 bitshift = 7;
 106	u8 array_index = 0;
 107	int number_of_bits = number_of_bytes * 8;
 108	u16 remainder = 0;
 109
 110	while (number_of_bits != 0) {
 111		number_of_bits--;
 112		remainder <<= 1;
 113		remainder |= (data[array_index] & bitmask) >> bitshift;
 114		bitmask >>= 1;
 115		bitshift--;
 116		if (bitmask == 0) {
 117			bitmask = 0x80;
 118			bitshift = 7;
 119			array_index++;
 120		}
 121		if ((remainder & 0x100) == 0x100)
 122			remainder ^= 0xd5;
 123	}
 124
 125	number_of_bits = 8;
 126	while (number_of_bits != 0) {
 127		number_of_bits--;
 128		remainder <<= 1;
 129		if ((remainder & 0x100) != 0)
 130			remainder ^= 0xd5;
 131	}
 132
 133	return remainder & 0xff;
 134}
 135static inline u8 drm_dp_calc_sb_hdr_size(struct drm_dp_sideband_msg_hdr *hdr)
 136{
 137	u8 size = 3;
 138	size += (hdr->lct / 2);
 139	return size;
 140}
 141
 142static void drm_dp_encode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
 143					   u8 *buf, int *len)
 144{
 145	int idx = 0;
 146	int i;
 147	u8 crc4;
 148	buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
 149	for (i = 0; i < (hdr->lct / 2); i++)
 150		buf[idx++] = hdr->rad[i];
 151	buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
 152		(hdr->msg_len & 0x3f);
 153	buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
 154
 155	crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
 156	buf[idx - 1] |= (crc4 & 0xf);
 157
 158	*len = idx;
 159}
 160
 161static bool drm_dp_decode_sideband_msg_hdr(struct drm_dp_sideband_msg_hdr *hdr,
 162					   u8 *buf, int buflen, u8 *hdrlen)
 163{
 164	u8 crc4;
 165	u8 len;
 166	int i;
 167	u8 idx;
 168	if (buf[0] == 0)
 169		return false;
 170	len = 3;
 171	len += ((buf[0] & 0xf0) >> 4) / 2;
 172	if (len > buflen)
 173		return false;
 174	crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
 175
 176	if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
 177		DRM_DEBUG_KMS("crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
 178		return false;
 179	}
 180
 181	hdr->lct = (buf[0] & 0xf0) >> 4;
 182	hdr->lcr = (buf[0] & 0xf);
 183	idx = 1;
 184	for (i = 0; i < (hdr->lct / 2); i++)
 185		hdr->rad[i] = buf[idx++];
 186	hdr->broadcast = (buf[idx] >> 7) & 0x1;
 187	hdr->path_msg = (buf[idx] >> 6) & 0x1;
 188	hdr->msg_len = buf[idx] & 0x3f;
 189	idx++;
 190	hdr->somt = (buf[idx] >> 7) & 0x1;
 191	hdr->eomt = (buf[idx] >> 6) & 0x1;
 192	hdr->seqno = (buf[idx] >> 4) & 0x1;
 193	idx++;
 194	*hdrlen = idx;
 195	return true;
 196}
 197
 198static void drm_dp_encode_sideband_req(struct drm_dp_sideband_msg_req_body *req,
 199				       struct drm_dp_sideband_msg_tx *raw)
 200{
 201	int idx = 0;
 202	int i;
 203	u8 *buf = raw->msg;
 204	buf[idx++] = req->req_type & 0x7f;
 205
 206	switch (req->req_type) {
 207	case DP_ENUM_PATH_RESOURCES:
 208		buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
 209		idx++;
 210		break;
 211	case DP_ALLOCATE_PAYLOAD:
 212		buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
 213			(req->u.allocate_payload.number_sdp_streams & 0xf);
 214		idx++;
 215		buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
 216		idx++;
 217		buf[idx] = (req->u.allocate_payload.pbn >> 8);
 218		idx++;
 219		buf[idx] = (req->u.allocate_payload.pbn & 0xff);
 220		idx++;
 221		for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
 222			buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) << 4) |
 223				(req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
 224			idx++;
 225		}
 226		if (req->u.allocate_payload.number_sdp_streams & 1) {
 227			i = req->u.allocate_payload.number_sdp_streams - 1;
 228			buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
 229			idx++;
 230		}
 231		break;
 232	case DP_QUERY_PAYLOAD:
 233		buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
 234		idx++;
 235		buf[idx] = (req->u.query_payload.vcpi & 0x7f);
 236		idx++;
 237		break;
 238	case DP_REMOTE_DPCD_READ:
 239		buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
 240		buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
 241		idx++;
 242		buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
 243		idx++;
 244		buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
 245		idx++;
 246		buf[idx] = (req->u.dpcd_read.num_bytes);
 247		idx++;
 248		break;
 249
 250	case DP_REMOTE_DPCD_WRITE:
 251		buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
 252		buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
 253		idx++;
 254		buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
 255		idx++;
 256		buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
 257		idx++;
 258		buf[idx] = (req->u.dpcd_write.num_bytes);
 259		idx++;
 260		memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
 261		idx += req->u.dpcd_write.num_bytes;
 262		break;
 263	case DP_REMOTE_I2C_READ:
 264		buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
 265		buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
 266		idx++;
 267		for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
 268			buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
 269			idx++;
 270			buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
 271			idx++;
 272			memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, req->u.i2c_read.transactions[i].num_bytes);
 273			idx += req->u.i2c_read.transactions[i].num_bytes;
 274
 275			buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 5;
 276			buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 0xf);
 277			idx++;
 278		}
 279		buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
 280		idx++;
 281		buf[idx] = (req->u.i2c_read.num_bytes_read);
 282		idx++;
 283		break;
 284
 285	case DP_REMOTE_I2C_WRITE:
 286		buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
 287		idx++;
 288		buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
 289		idx++;
 290		buf[idx] = (req->u.i2c_write.num_bytes);
 291		idx++;
 292		memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
 293		idx += req->u.i2c_write.num_bytes;
 294		break;
 295	}
 296	raw->cur_len = idx;
 297}
 298
 299static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
 300{
 301	u8 crc4;
 302	crc4 = drm_dp_msg_data_crc4(msg, len);
 303	msg[len] = crc4;
 304}
 305
 306static void drm_dp_encode_sideband_reply(struct drm_dp_sideband_msg_reply_body *rep,
 307					 struct drm_dp_sideband_msg_tx *raw)
 308{
 309	int idx = 0;
 310	u8 *buf = raw->msg;
 311
 312	buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
 313
 314	raw->cur_len = idx;
 315}
 316
 317/* this adds a chunk of msg to the builder to get the final msg */
 318static bool drm_dp_sideband_msg_build(struct drm_dp_sideband_msg_rx *msg,
 319				      u8 *replybuf, u8 replybuflen, bool hdr)
 320{
 321	int ret;
 322	u8 crc4;
 323
 324	if (hdr) {
 325		u8 hdrlen;
 326		struct drm_dp_sideband_msg_hdr recv_hdr;
 327		ret = drm_dp_decode_sideband_msg_hdr(&recv_hdr, replybuf, replybuflen, &hdrlen);
 328		if (ret == false) {
 329			print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16, 1, replybuf, replybuflen, false);
 330			return false;
 331		}
 332
 333		/* get length contained in this portion */
 334		msg->curchunk_len = recv_hdr.msg_len;
 335		msg->curchunk_hdrlen = hdrlen;
 336
 337		/* we have already gotten an somt - don't bother parsing */
 338		if (recv_hdr.somt && msg->have_somt)
 339			return false;
 340
 341		if (recv_hdr.somt) {
 342			memcpy(&msg->initial_hdr, &recv_hdr, sizeof(struct drm_dp_sideband_msg_hdr));
 343			msg->have_somt = true;
 344		}
 345		if (recv_hdr.eomt)
 346			msg->have_eomt = true;
 347
 348		/* copy the bytes for the remainder of this header chunk */
 349		msg->curchunk_idx = min(msg->curchunk_len, (u8)(replybuflen - hdrlen));
 350		memcpy(&msg->chunk[0], replybuf + hdrlen, msg->curchunk_idx);
 351	} else {
 352		memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
 353		msg->curchunk_idx += replybuflen;
 354	}
 355
 356	if (msg->curchunk_idx >= msg->curchunk_len) {
 357		/* do CRC */
 358		crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
 359		/* copy chunk into bigger msg */
 360		memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
 361		msg->curlen += msg->curchunk_len - 1;
 362	}
 363	return true;
 364}
 365
 366static bool drm_dp_sideband_parse_link_address(struct drm_dp_sideband_msg_rx *raw,
 367					       struct drm_dp_sideband_msg_reply_body *repmsg)
 368{
 369	int idx = 1;
 370	int i;
 371	memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
 372	idx += 16;
 373	repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
 374	idx++;
 375	if (idx > raw->curlen)
 376		goto fail_len;
 377	for (i = 0; i < repmsg->u.link_addr.nports; i++) {
 378		if (raw->msg[idx] & 0x80)
 379			repmsg->u.link_addr.ports[i].input_port = 1;
 380
 381		repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) & 0x7;
 382		repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
 383
 384		idx++;
 385		if (idx > raw->curlen)
 386			goto fail_len;
 387		repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
 388		repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
 389		if (repmsg->u.link_addr.ports[i].input_port == 0)
 390			repmsg->u.link_addr.ports[i].legacy_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
 391		idx++;
 392		if (idx > raw->curlen)
 393			goto fail_len;
 394		if (repmsg->u.link_addr.ports[i].input_port == 0) {
 395			repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
 396			idx++;
 397			if (idx > raw->curlen)
 398				goto fail_len;
 399			memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
 400			idx += 16;
 401			if (idx > raw->curlen)
 402				goto fail_len;
 403			repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) & 0xf;
 404			repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 0xf);
 405			idx++;
 406
 407		}
 408		if (idx > raw->curlen)
 409			goto fail_len;
 410	}
 411
 412	return true;
 413fail_len:
 414	DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 415	return false;
 416}
 417
 418static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx *raw,
 419						   struct drm_dp_sideband_msg_reply_body *repmsg)
 420{
 421	int idx = 1;
 422	repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
 423	idx++;
 424	if (idx > raw->curlen)
 425		goto fail_len;
 426	repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
 427	if (idx > raw->curlen)
 428		goto fail_len;
 429
 430	memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_dpcd_read_ack.num_bytes);
 431	return true;
 432fail_len:
 433	DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, raw->curlen);
 434	return false;
 435}
 436
 437static bool drm_dp_sideband_parse_remote_dpcd_write(struct drm_dp_sideband_msg_rx *raw,
 438						      struct drm_dp_sideband_msg_reply_body *repmsg)
 439{
 440	int idx = 1;
 441	repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
 442	idx++;
 443	if (idx > raw->curlen)
 444		goto fail_len;
 445	return true;
 446fail_len:
 447	DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
 448	return false;
 449}
 450
 451static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct drm_dp_sideband_msg_rx *raw,
 452						      struct drm_dp_sideband_msg_reply_body *repmsg)
 453{
 454	int idx = 1;
 455
 456	repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
 457	idx++;
 458	if (idx > raw->curlen)
 459		goto fail_len;
 460	repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
 461	idx++;
 462	/* TODO check */
 463	memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], repmsg->u.remote_i2c_read_ack.num_bytes);
 464	return true;
 465fail_len:
 466	DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, raw->curlen);
 467	return false;
 468}
 469
 470static bool drm_dp_sideband_parse_enum_path_resources_ack(struct drm_dp_sideband_msg_rx *raw,
 471							  struct drm_dp_sideband_msg_reply_body *repmsg)
 472{
 473	int idx = 1;
 474	repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
 475	idx++;
 476	if (idx > raw->curlen)
 477		goto fail_len;
 478	repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 479	idx += 2;
 480	if (idx > raw->curlen)
 481		goto fail_len;
 482	repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 483	idx += 2;
 484	if (idx > raw->curlen)
 485		goto fail_len;
 486	return true;
 487fail_len:
 488	DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, raw->curlen);
 489	return false;
 490}
 491
 492static bool drm_dp_sideband_parse_allocate_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 493							  struct drm_dp_sideband_msg_reply_body *repmsg)
 494{
 495	int idx = 1;
 496	repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 497	idx++;
 498	if (idx > raw->curlen)
 499		goto fail_len;
 500	repmsg->u.allocate_payload.vcpi = raw->msg[idx];
 501	idx++;
 502	if (idx > raw->curlen)
 503		goto fail_len;
 504	repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx+1]);
 505	idx += 2;
 506	if (idx > raw->curlen)
 507		goto fail_len;
 508	return true;
 509fail_len:
 510	DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, raw->curlen);
 511	return false;
 512}
 513
 514static bool drm_dp_sideband_parse_query_payload_ack(struct drm_dp_sideband_msg_rx *raw,
 515						    struct drm_dp_sideband_msg_reply_body *repmsg)
 516{
 517	int idx = 1;
 518	repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
 519	idx++;
 520	if (idx > raw->curlen)
 521		goto fail_len;
 522	repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
 523	idx += 2;
 524	if (idx > raw->curlen)
 525		goto fail_len;
 526	return true;
 527fail_len:
 528	DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, raw->curlen);
 529	return false;
 530}
 531
 532static bool drm_dp_sideband_parse_reply(struct drm_dp_sideband_msg_rx *raw,
 533					struct drm_dp_sideband_msg_reply_body *msg)
 534{
 535	memset(msg, 0, sizeof(*msg));
 536	msg->reply_type = (raw->msg[0] & 0x80) >> 7;
 537	msg->req_type = (raw->msg[0] & 0x7f);
 538
 539	if (msg->reply_type) {
 540		memcpy(msg->u.nak.guid, &raw->msg[1], 16);
 541		msg->u.nak.reason = raw->msg[17];
 542		msg->u.nak.nak_data = raw->msg[18];
 543		return false;
 544	}
 545
 546	switch (msg->req_type) {
 547	case DP_LINK_ADDRESS:
 548		return drm_dp_sideband_parse_link_address(raw, msg);
 549	case DP_QUERY_PAYLOAD:
 550		return drm_dp_sideband_parse_query_payload_ack(raw, msg);
 551	case DP_REMOTE_DPCD_READ:
 552		return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
 553	case DP_REMOTE_DPCD_WRITE:
 554		return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
 555	case DP_REMOTE_I2C_READ:
 556		return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
 557	case DP_ENUM_PATH_RESOURCES:
 558		return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
 559	case DP_ALLOCATE_PAYLOAD:
 560		return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
 561	default:
 562		DRM_ERROR("Got unknown reply 0x%02x\n", msg->req_type);
 563		return false;
 564	}
 565}
 566
 567static bool drm_dp_sideband_parse_connection_status_notify(struct drm_dp_sideband_msg_rx *raw,
 568							   struct drm_dp_sideband_msg_req_body *msg)
 569{
 570	int idx = 1;
 571
 572	msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
 573	idx++;
 574	if (idx > raw->curlen)
 575		goto fail_len;
 576
 577	memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
 578	idx += 16;
 579	if (idx > raw->curlen)
 580		goto fail_len;
 581
 582	msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
 583	msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 5) & 0x1;
 584	msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
 585	msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
 586	msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
 587	idx++;
 588	return true;
 589fail_len:
 590	DRM_DEBUG_KMS("connection status reply parse length fail %d %d\n", idx, raw->curlen);
 591	return false;
 592}
 593
 594static bool drm_dp_sideband_parse_resource_status_notify(struct drm_dp_sideband_msg_rx *raw,
 595							   struct drm_dp_sideband_msg_req_body *msg)
 596{
 597	int idx = 1;
 598
 599	msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
 600	idx++;
 601	if (idx > raw->curlen)
 602		goto fail_len;
 603
 604	memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
 605	idx += 16;
 606	if (idx > raw->curlen)
 607		goto fail_len;
 608
 609	msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | (raw->msg[idx + 1]);
 610	idx++;
 611	return true;
 612fail_len:
 613	DRM_DEBUG_KMS("resource status reply parse length fail %d %d\n", idx, raw->curlen);
 614	return false;
 615}
 616
 617static bool drm_dp_sideband_parse_req(struct drm_dp_sideband_msg_rx *raw,
 618				      struct drm_dp_sideband_msg_req_body *msg)
 619{
 620	memset(msg, 0, sizeof(*msg));
 621	msg->req_type = (raw->msg[0] & 0x7f);
 622
 623	switch (msg->req_type) {
 624	case DP_CONNECTION_STATUS_NOTIFY:
 625		return drm_dp_sideband_parse_connection_status_notify(raw, msg);
 626	case DP_RESOURCE_STATUS_NOTIFY:
 627		return drm_dp_sideband_parse_resource_status_notify(raw, msg);
 628	default:
 629		DRM_ERROR("Got unknown request 0x%02x\n", msg->req_type);
 630		return false;
 631	}
 632}
 633
 634static int build_dpcd_write(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32 offset, u8 num_bytes, u8 *bytes)
 635{
 636	struct drm_dp_sideband_msg_req_body req;
 637
 638	req.req_type = DP_REMOTE_DPCD_WRITE;
 639	req.u.dpcd_write.port_number = port_num;
 640	req.u.dpcd_write.dpcd_address = offset;
 641	req.u.dpcd_write.num_bytes = num_bytes;
 642	req.u.dpcd_write.bytes = bytes;
 643	drm_dp_encode_sideband_req(&req, msg);
 644
 645	return 0;
 646}
 647
 648static int build_link_address(struct drm_dp_sideband_msg_tx *msg)
 649{
 650	struct drm_dp_sideband_msg_req_body req;
 651
 652	req.req_type = DP_LINK_ADDRESS;
 653	drm_dp_encode_sideband_req(&req, msg);
 654	return 0;
 655}
 656
 657static int build_enum_path_resources(struct drm_dp_sideband_msg_tx *msg, int port_num)
 658{
 659	struct drm_dp_sideband_msg_req_body req;
 660
 661	req.req_type = DP_ENUM_PATH_RESOURCES;
 662	req.u.port_num.port_number = port_num;
 663	drm_dp_encode_sideband_req(&req, msg);
 664	msg->path_msg = true;
 665	return 0;
 666}
 667
 668static int build_allocate_payload(struct drm_dp_sideband_msg_tx *msg, int port_num,
 669				  u8 vcpi, uint16_t pbn,
 670				  u8 number_sdp_streams,
 671				  u8 *sdp_stream_sink)
 672{
 673	struct drm_dp_sideband_msg_req_body req;
 674	memset(&req, 0, sizeof(req));
 675	req.req_type = DP_ALLOCATE_PAYLOAD;
 676	req.u.allocate_payload.port_number = port_num;
 677	req.u.allocate_payload.vcpi = vcpi;
 678	req.u.allocate_payload.pbn = pbn;
 679	req.u.allocate_payload.number_sdp_streams = number_sdp_streams;
 680	memcpy(req.u.allocate_payload.sdp_stream_sink, sdp_stream_sink,
 681		   number_sdp_streams);
 682	drm_dp_encode_sideband_req(&req, msg);
 683	msg->path_msg = true;
 684	return 0;
 685}
 686
 687static int drm_dp_mst_assign_payload_id(struct drm_dp_mst_topology_mgr *mgr,
 688					struct drm_dp_vcpi *vcpi)
 689{
 690	int ret, vcpi_ret;
 691
 692	mutex_lock(&mgr->payload_lock);
 693	ret = find_first_zero_bit(&mgr->payload_mask, mgr->max_payloads + 1);
 694	if (ret > mgr->max_payloads) {
 695		ret = -EINVAL;
 696		DRM_DEBUG_KMS("out of payload ids %d\n", ret);
 697		goto out_unlock;
 698	}
 699
 700	vcpi_ret = find_first_zero_bit(&mgr->vcpi_mask, mgr->max_payloads + 1);
 701	if (vcpi_ret > mgr->max_payloads) {
 702		ret = -EINVAL;
 703		DRM_DEBUG_KMS("out of vcpi ids %d\n", ret);
 704		goto out_unlock;
 705	}
 706
 707	set_bit(ret, &mgr->payload_mask);
 708	set_bit(vcpi_ret, &mgr->vcpi_mask);
 709	vcpi->vcpi = vcpi_ret + 1;
 710	mgr->proposed_vcpis[ret - 1] = vcpi;
 711out_unlock:
 712	mutex_unlock(&mgr->payload_lock);
 713	return ret;
 714}
 715
 716static void drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr *mgr,
 717				      int vcpi)
 718{
 719	int i;
 720	if (vcpi == 0)
 721		return;
 722
 723	mutex_lock(&mgr->payload_lock);
 724	DRM_DEBUG_KMS("putting payload %d\n", vcpi);
 725	clear_bit(vcpi - 1, &mgr->vcpi_mask);
 726
 727	for (i = 0; i < mgr->max_payloads; i++) {
 728		if (mgr->proposed_vcpis[i])
 729			if (mgr->proposed_vcpis[i]->vcpi == vcpi) {
 730				mgr->proposed_vcpis[i] = NULL;
 731				clear_bit(i + 1, &mgr->payload_mask);
 732			}
 733	}
 734	mutex_unlock(&mgr->payload_lock);
 735}
 736
 737static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
 738			      struct drm_dp_sideband_msg_tx *txmsg)
 739{
 740	bool ret;
 741
 742	/*
 743	 * All updates to txmsg->state are protected by mgr->qlock, and the two
 744	 * cases we check here are terminal states. For those the barriers
 745	 * provided by the wake_up/wait_event pair are enough.
 746	 */
 747	ret = (txmsg->state == DRM_DP_SIDEBAND_TX_RX ||
 748	       txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT);
 749	return ret;
 750}
 751
 752static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
 753				    struct drm_dp_sideband_msg_tx *txmsg)
 754{
 755	struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
 756	int ret;
 757
 758	ret = wait_event_timeout(mgr->tx_waitq,
 759				 check_txmsg_state(mgr, txmsg),
 760				 (4 * HZ));
 761	mutex_lock(&mstb->mgr->qlock);
 762	if (ret > 0) {
 763		if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
 764			ret = -EIO;
 765			goto out;
 766		}
 767	} else {
 768		DRM_DEBUG_KMS("timedout msg send %p %d %d\n", txmsg, txmsg->state, txmsg->seqno);
 769
 770		/* dump some state */
 771		ret = -EIO;
 772
 773		/* remove from q */
 774		if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
 775		    txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND) {
 776			list_del(&txmsg->next);
 777		}
 778
 779		if (txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
 780		    txmsg->state == DRM_DP_SIDEBAND_TX_SENT) {
 781			mstb->tx_slots[txmsg->seqno] = NULL;
 782		}
 783	}
 784out:
 785	mutex_unlock(&mgr->qlock);
 786
 787	return ret;
 788}
 789
 790static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, u8 *rad)
 791{
 792	struct drm_dp_mst_branch *mstb;
 793
 794	mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
 795	if (!mstb)
 796		return NULL;
 797
 798	mstb->lct = lct;
 799	if (lct > 1)
 800		memcpy(mstb->rad, rad, lct / 2);
 801	INIT_LIST_HEAD(&mstb->ports);
 802	kref_init(&mstb->kref);
 803	return mstb;
 804}
 805
 806static void drm_dp_free_mst_port(struct kref *kref);
 807
 808static void drm_dp_free_mst_branch_device(struct kref *kref)
 809{
 810	struct drm_dp_mst_branch *mstb = container_of(kref, struct drm_dp_mst_branch, kref);
 811	if (mstb->port_parent) {
 812		if (list_empty(&mstb->port_parent->next))
 813			kref_put(&mstb->port_parent->kref, drm_dp_free_mst_port);
 814	}
 815	kfree(mstb);
 816}
 817
 818static void drm_dp_destroy_mst_branch_device(struct kref *kref)
 819{
 820	struct drm_dp_mst_branch *mstb = container_of(kref, struct drm_dp_mst_branch, kref);
 821	struct drm_dp_mst_port *port, *tmp;
 822	bool wake_tx = false;
 823
 824	/*
 825	 * init kref again to be used by ports to remove mst branch when it is
 826	 * not needed anymore
 827	 */
 828	kref_init(kref);
 829
 830	if (mstb->port_parent && list_empty(&mstb->port_parent->next))
 831		kref_get(&mstb->port_parent->kref);
 832
 833	/*
 834	 * destroy all ports - don't need lock
 835	 * as there are no more references to the mst branch
 836	 * device at this point.
 837	 */
 838	list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
 839		list_del(&port->next);
 840		drm_dp_put_port(port);
 841	}
 842
 843	/* drop any tx slots msg */
 844	mutex_lock(&mstb->mgr->qlock);
 845	if (mstb->tx_slots[0]) {
 846		mstb->tx_slots[0]->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
 847		mstb->tx_slots[0] = NULL;
 848		wake_tx = true;
 849	}
 850	if (mstb->tx_slots[1]) {
 851		mstb->tx_slots[1]->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
 852		mstb->tx_slots[1] = NULL;
 853		wake_tx = true;
 854	}
 855	mutex_unlock(&mstb->mgr->qlock);
 856
 857	if (wake_tx)
 858		wake_up(&mstb->mgr->tx_waitq);
 859
 860	kref_put(kref, drm_dp_free_mst_branch_device);
 861}
 862
 863static void drm_dp_put_mst_branch_device(struct drm_dp_mst_branch *mstb)
 864{
 865	kref_put(&mstb->kref, drm_dp_destroy_mst_branch_device);
 866}
 867
 868
 869static void drm_dp_port_teardown_pdt(struct drm_dp_mst_port *port, int old_pdt)
 870{
 871	struct drm_dp_mst_branch *mstb;
 872
 873	switch (old_pdt) {
 874	case DP_PEER_DEVICE_DP_LEGACY_CONV:
 875	case DP_PEER_DEVICE_SST_SINK:
 876		/* remove i2c over sideband */
 877		drm_dp_mst_unregister_i2c_bus(&port->aux);
 878		break;
 879	case DP_PEER_DEVICE_MST_BRANCHING:
 880		mstb = port->mstb;
 881		port->mstb = NULL;
 882		drm_dp_put_mst_branch_device(mstb);
 883		break;
 884	}
 885}
 886
 887static void drm_dp_destroy_port(struct kref *kref)
 888{
 889	struct drm_dp_mst_port *port = container_of(kref, struct drm_dp_mst_port, kref);
 890	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
 891
 892	if (!port->input) {
 893		port->vcpi.num_slots = 0;
 894
 895		kfree(port->cached_edid);
 896
 897		/*
 898		 * The only time we don't have a connector
 899		 * on an output port is if the connector init
 900		 * fails.
 901		 */
 902		if (port->connector) {
 903			/* we can't destroy the connector here, as
 904			 * we might be holding the mode_config.mutex
 905			 * from an EDID retrieval */
 906
 907			mutex_lock(&mgr->destroy_connector_lock);
 908			kref_get(&port->parent->kref);
 909			list_add(&port->next, &mgr->destroy_connector_list);
 910			mutex_unlock(&mgr->destroy_connector_lock);
 911			schedule_work(&mgr->destroy_connector_work);
 912			return;
 913		}
 914		/* no need to clean up vcpi
 915		 * as if we have no connector we never setup a vcpi */
 916		drm_dp_port_teardown_pdt(port, port->pdt);
 917		port->pdt = DP_PEER_DEVICE_NONE;
 918	}
 919	kfree(port);
 920}
 921
 922static void drm_dp_put_port(struct drm_dp_mst_port *port)
 923{
 924	kref_put(&port->kref, drm_dp_destroy_port);
 925}
 926
 927static struct drm_dp_mst_branch *drm_dp_mst_get_validated_mstb_ref_locked(struct drm_dp_mst_branch *mstb, struct drm_dp_mst_branch *to_find)
 928{
 929	struct drm_dp_mst_port *port;
 930	struct drm_dp_mst_branch *rmstb;
 931	if (to_find == mstb) {
 932		kref_get(&mstb->kref);
 933		return mstb;
 934	}
 935	list_for_each_entry(port, &mstb->ports, next) {
 936		if (port->mstb) {
 937			rmstb = drm_dp_mst_get_validated_mstb_ref_locked(port->mstb, to_find);
 938			if (rmstb)
 939				return rmstb;
 940		}
 941	}
 942	return NULL;
 943}
 944
 945static struct drm_dp_mst_branch *drm_dp_get_validated_mstb_ref(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_branch *mstb)
 946{
 947	struct drm_dp_mst_branch *rmstb = NULL;
 948	mutex_lock(&mgr->lock);
 949	if (mgr->mst_primary)
 950		rmstb = drm_dp_mst_get_validated_mstb_ref_locked(mgr->mst_primary, mstb);
 951	mutex_unlock(&mgr->lock);
 952	return rmstb;
 953}
 954
 955static struct drm_dp_mst_port *drm_dp_mst_get_port_ref_locked(struct drm_dp_mst_branch *mstb, struct drm_dp_mst_port *to_find)
 956{
 957	struct drm_dp_mst_port *port, *mport;
 958
 959	list_for_each_entry(port, &mstb->ports, next) {
 960		if (port == to_find) {
 961			kref_get(&port->kref);
 962			return port;
 963		}
 964		if (port->mstb) {
 965			mport = drm_dp_mst_get_port_ref_locked(port->mstb, to_find);
 966			if (mport)
 967				return mport;
 968		}
 969	}
 970	return NULL;
 971}
 972
 973static struct drm_dp_mst_port *drm_dp_get_validated_port_ref(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
 974{
 975	struct drm_dp_mst_port *rport = NULL;
 976	mutex_lock(&mgr->lock);
 977	if (mgr->mst_primary)
 978		rport = drm_dp_mst_get_port_ref_locked(mgr->mst_primary, port);
 979	mutex_unlock(&mgr->lock);
 980	return rport;
 981}
 982
 983static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
 984{
 985	struct drm_dp_mst_port *port;
 986
 987	list_for_each_entry(port, &mstb->ports, next) {
 988		if (port->port_num == port_num) {
 989			kref_get(&port->kref);
 990			return port;
 991		}
 992	}
 993
 994	return NULL;
 995}
 996
 997/*
 998 * calculate a new RAD for this MST branch device
 999 * if parent has an LCT of 2 then it has 1 nibble of RAD,
1000 * if parent has an LCT of 3 then it has 2 nibbles of RAD,
1001 */
1002static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
1003				 u8 *rad)
1004{
1005	int parent_lct = port->parent->lct;
1006	int shift = 4;
1007	int idx = (parent_lct - 1) / 2;
1008	if (parent_lct > 1) {
1009		memcpy(rad, port->parent->rad, idx + 1);
1010		shift = (parent_lct % 2) ? 4 : 0;
1011	} else
1012		rad[0] = 0;
1013
1014	rad[idx] |= port->port_num << shift;
1015	return parent_lct + 1;
1016}
1017
1018/*
1019 * return sends link address for new mstb
1020 */
1021static bool drm_dp_port_setup_pdt(struct drm_dp_mst_port *port)
1022{
1023	int ret;
1024	u8 rad[6], lct;
1025	bool send_link = false;
1026	switch (port->pdt) {
1027	case DP_PEER_DEVICE_DP_LEGACY_CONV:
1028	case DP_PEER_DEVICE_SST_SINK:
1029		/* add i2c over sideband */
1030		ret = drm_dp_mst_register_i2c_bus(&port->aux);
1031		break;
1032	case DP_PEER_DEVICE_MST_BRANCHING:
1033		lct = drm_dp_calculate_rad(port, rad);
1034
1035		port->mstb = drm_dp_add_mst_branch_device(lct, rad);
1036		port->mstb->mgr = port->mgr;
1037		port->mstb->port_parent = port;
1038
1039		send_link = true;
1040		break;
1041	}
1042	return send_link;
1043}
1044
1045static void drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
1046{
1047	int ret;
1048
1049	memcpy(mstb->guid, guid, 16);
1050
1051	if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
1052		if (mstb->port_parent) {
1053			ret = drm_dp_send_dpcd_write(
1054					mstb->mgr,
1055					mstb->port_parent,
1056					DP_GUID,
1057					16,
1058					mstb->guid);
1059		} else {
1060
1061			ret = drm_dp_dpcd_write(
1062					mstb->mgr->aux,
1063					DP_GUID,
1064					mstb->guid,
1065					16);
1066		}
1067	}
1068}
1069
1070static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
1071				int pnum,
1072				char *proppath,
1073				size_t proppath_size)
1074{
1075	int i;
1076	char temp[8];
1077	snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
1078	for (i = 0; i < (mstb->lct - 1); i++) {
1079		int shift = (i % 2) ? 0 : 4;
1080		int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
1081		snprintf(temp, sizeof(temp), "-%d", port_num);
1082		strlcat(proppath, temp, proppath_size);
1083	}
1084	snprintf(temp, sizeof(temp), "-%d", pnum);
1085	strlcat(proppath, temp, proppath_size);
1086}
1087
1088static void drm_dp_add_port(struct drm_dp_mst_branch *mstb,
1089			    struct device *dev,
1090			    struct drm_dp_link_addr_reply_port *port_msg)
1091{
1092	struct drm_dp_mst_port *port;
1093	bool ret;
1094	bool created = false;
1095	int old_pdt = 0;
1096	int old_ddps = 0;
1097	port = drm_dp_get_port(mstb, port_msg->port_number);
1098	if (!port) {
1099		port = kzalloc(sizeof(*port), GFP_KERNEL);
1100		if (!port)
1101			return;
1102		kref_init(&port->kref);
1103		port->parent = mstb;
1104		port->port_num = port_msg->port_number;
1105		port->mgr = mstb->mgr;
1106		port->aux.name = "DPMST";
1107		port->aux.dev = dev;
1108		created = true;
1109	} else {
1110		old_pdt = port->pdt;
1111		old_ddps = port->ddps;
1112	}
1113
1114	port->pdt = port_msg->peer_device_type;
1115	port->input = port_msg->input_port;
1116	port->mcs = port_msg->mcs;
1117	port->ddps = port_msg->ddps;
1118	port->ldps = port_msg->legacy_device_plug_status;
1119	port->dpcd_rev = port_msg->dpcd_revision;
1120	port->num_sdp_streams = port_msg->num_sdp_streams;
1121	port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
1122
1123	/* manage mstb port lists with mgr lock - take a reference
1124	   for this list */
1125	if (created) {
1126		mutex_lock(&mstb->mgr->lock);
1127		kref_get(&port->kref);
1128		list_add(&port->next, &mstb->ports);
1129		mutex_unlock(&mstb->mgr->lock);
1130	}
1131
1132	if (old_ddps != port->ddps) {
1133		if (port->ddps) {
1134			if (!port->input)
1135				drm_dp_send_enum_path_resources(mstb->mgr, mstb, port);
1136		} else {
1137			port->available_pbn = 0;
1138			}
1139	}
1140
1141	if (old_pdt != port->pdt && !port->input) {
1142		drm_dp_port_teardown_pdt(port, old_pdt);
1143
1144		ret = drm_dp_port_setup_pdt(port);
1145		if (ret == true)
1146			drm_dp_send_link_address(mstb->mgr, port->mstb);
1147	}
1148
1149	if (created && !port->input) {
1150		char proppath[255];
1151
1152		build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
1153		port->connector = (*mstb->mgr->cbs->add_connector)(mstb->mgr, port, proppath);
1154		if (!port->connector) {
1155			/* remove it from the port list */
1156			mutex_lock(&mstb->mgr->lock);
1157			list_del(&port->next);
1158			mutex_unlock(&mstb->mgr->lock);
1159			/* drop port list reference */
1160			drm_dp_put_port(port);
1161			goto out;
1162		}
1163		if ((port->pdt == DP_PEER_DEVICE_DP_LEGACY_CONV ||
1164		     port->pdt == DP_PEER_DEVICE_SST_SINK) &&
1165		    port->port_num >= DP_MST_LOGICAL_PORT_0) {
1166			port->cached_edid = drm_get_edid(port->connector, &port->aux.ddc);
1167			drm_mode_connector_set_tile_property(port->connector);
1168		}
1169		(*mstb->mgr->cbs->register_connector)(port->connector);
1170	}
1171
1172out:
1173	/* put reference to this port */
1174	drm_dp_put_port(port);
1175}
1176
1177static void drm_dp_update_port(struct drm_dp_mst_branch *mstb,
1178			       struct drm_dp_connection_status_notify *conn_stat)
1179{
1180	struct drm_dp_mst_port *port;
1181	int old_pdt;
1182	int old_ddps;
1183	bool dowork = false;
1184	port = drm_dp_get_port(mstb, conn_stat->port_number);
1185	if (!port)
1186		return;
1187
1188	old_ddps = port->ddps;
1189	old_pdt = port->pdt;
1190	port->pdt = conn_stat->peer_device_type;
1191	port->mcs = conn_stat->message_capability_status;
1192	port->ldps = conn_stat->legacy_device_plug_status;
1193	port->ddps = conn_stat->displayport_device_plug_status;
1194
1195	if (old_ddps != port->ddps) {
1196		if (port->ddps) {
1197			dowork = true;
1198		} else {
1199			port->available_pbn = 0;
1200		}
1201	}
1202	if (old_pdt != port->pdt && !port->input) {
1203		drm_dp_port_teardown_pdt(port, old_pdt);
1204
1205		if (drm_dp_port_setup_pdt(port))
1206			dowork = true;
1207	}
1208
1209	drm_dp_put_port(port);
1210	if (dowork)
1211		queue_work(system_long_wq, &mstb->mgr->work);
1212
1213}
1214
1215static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
1216							       u8 lct, u8 *rad)
1217{
1218	struct drm_dp_mst_branch *mstb;
1219	struct drm_dp_mst_port *port;
1220	int i;
1221	/* find the port by iterating down */
1222
1223	mutex_lock(&mgr->lock);
1224	mstb = mgr->mst_primary;
1225
1226	for (i = 0; i < lct - 1; i++) {
1227		int shift = (i % 2) ? 0 : 4;
1228		int port_num = (rad[i / 2] >> shift) & 0xf;
1229
1230		list_for_each_entry(port, &mstb->ports, next) {
1231			if (port->port_num == port_num) {
1232				mstb = port->mstb;
1233				if (!mstb) {
1234					DRM_ERROR("failed to lookup MSTB with lct %d, rad %02x\n", lct, rad[0]);
1235					goto out;
1236				}
1237
1238				break;
1239			}
1240		}
1241	}
1242	kref_get(&mstb->kref);
1243out:
1244	mutex_unlock(&mgr->lock);
1245	return mstb;
1246}
1247
1248static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
1249	struct drm_dp_mst_branch *mstb,
1250	uint8_t *guid)
1251{
1252	struct drm_dp_mst_branch *found_mstb;
1253	struct drm_dp_mst_port *port;
1254
1255	if (memcmp(mstb->guid, guid, 16) == 0)
1256		return mstb;
1257
1258
1259	list_for_each_entry(port, &mstb->ports, next) {
1260		if (!port->mstb)
1261			continue;
1262
1263		found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid);
1264
1265		if (found_mstb)
1266			return found_mstb;
1267	}
1268
1269	return NULL;
1270}
1271
1272static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device_by_guid(
1273	struct drm_dp_mst_topology_mgr *mgr,
1274	uint8_t *guid)
1275{
1276	struct drm_dp_mst_branch *mstb;
1277
1278	/* find the port by iterating down */
1279	mutex_lock(&mgr->lock);
1280
1281	mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
1282
1283	if (mstb)
1284		kref_get(&mstb->kref);
1285
1286	mutex_unlock(&mgr->lock);
1287	return mstb;
1288}
1289
1290static void drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
1291					       struct drm_dp_mst_branch *mstb)
1292{
1293	struct drm_dp_mst_port *port;
1294	struct drm_dp_mst_branch *mstb_child;
1295	if (!mstb->link_address_sent)
1296		drm_dp_send_link_address(mgr, mstb);
1297
1298	list_for_each_entry(port, &mstb->ports, next) {
1299		if (port->input)
1300			continue;
1301
1302		if (!port->ddps)
1303			continue;
1304
1305		if (!port->available_pbn)
1306			drm_dp_send_enum_path_resources(mgr, mstb, port);
1307
1308		if (port->mstb) {
1309			mstb_child = drm_dp_get_validated_mstb_ref(mgr, port->mstb);
1310			if (mstb_child) {
1311				drm_dp_check_and_send_link_address(mgr, mstb_child);
1312				drm_dp_put_mst_branch_device(mstb_child);
1313			}
1314		}
1315	}
1316}
1317
1318static void drm_dp_mst_link_probe_work(struct work_struct *work)
1319{
1320	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, work);
1321	struct drm_dp_mst_branch *mstb;
1322
1323	mutex_lock(&mgr->lock);
1324	mstb = mgr->mst_primary;
1325	if (mstb) {
1326		kref_get(&mstb->kref);
1327	}
1328	mutex_unlock(&mgr->lock);
1329	if (mstb) {
1330		drm_dp_check_and_send_link_address(mgr, mstb);
1331		drm_dp_put_mst_branch_device(mstb);
1332	}
1333}
1334
1335static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
1336				 u8 *guid)
1337{
1338	static u8 zero_guid[16];
1339
1340	if (!memcmp(guid, zero_guid, 16)) {
1341		u64 salt = get_jiffies_64();
1342		memcpy(&guid[0], &salt, sizeof(u64));
1343		memcpy(&guid[8], &salt, sizeof(u64));
1344		return false;
1345	}
1346	return true;
1347}
1348
1349#if 0
1350static int build_dpcd_read(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32 offset, u8 num_bytes)
1351{
1352	struct drm_dp_sideband_msg_req_body req;
1353
1354	req.req_type = DP_REMOTE_DPCD_READ;
1355	req.u.dpcd_read.port_number = port_num;
1356	req.u.dpcd_read.dpcd_address = offset;
1357	req.u.dpcd_read.num_bytes = num_bytes;
1358	drm_dp_encode_sideband_req(&req, msg);
1359
1360	return 0;
1361}
1362#endif
1363
1364static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
1365				    bool up, u8 *msg, int len)
1366{
1367	int ret;
1368	int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
1369	int tosend, total, offset;
1370	int retries = 0;
1371
1372retry:
1373	total = len;
1374	offset = 0;
1375	do {
1376		tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
1377
1378		ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
1379					&msg[offset],
1380					tosend);
1381		if (ret != tosend) {
1382			if (ret == -EIO && retries < 5) {
1383				retries++;
1384				goto retry;
1385			}
1386			DRM_DEBUG_KMS("failed to dpcd write %d %d\n", tosend, ret);
1387
1388			return -EIO;
1389		}
1390		offset += tosend;
1391		total -= tosend;
1392	} while (total > 0);
1393	return 0;
1394}
1395
1396static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
1397				  struct drm_dp_sideband_msg_tx *txmsg)
1398{
1399	struct drm_dp_mst_branch *mstb = txmsg->dst;
1400	u8 req_type;
1401
1402	/* both msg slots are full */
1403	if (txmsg->seqno == -1) {
1404		if (mstb->tx_slots[0] && mstb->tx_slots[1]) {
1405			DRM_DEBUG_KMS("%s: failed to find slot\n", __func__);
1406			return -EAGAIN;
1407		}
1408		if (mstb->tx_slots[0] == NULL && mstb->tx_slots[1] == NULL) {
1409			txmsg->seqno = mstb->last_seqno;
1410			mstb->last_seqno ^= 1;
1411		} else if (mstb->tx_slots[0] == NULL)
1412			txmsg->seqno = 0;
1413		else
1414			txmsg->seqno = 1;
1415		mstb->tx_slots[txmsg->seqno] = txmsg;
1416	}
1417
1418	req_type = txmsg->msg[0] & 0x7f;
1419	if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
1420		req_type == DP_RESOURCE_STATUS_NOTIFY)
1421		hdr->broadcast = 1;
1422	else
1423		hdr->broadcast = 0;
1424	hdr->path_msg = txmsg->path_msg;
1425	hdr->lct = mstb->lct;
1426	hdr->lcr = mstb->lct - 1;
1427	if (mstb->lct > 1)
1428		memcpy(hdr->rad, mstb->rad, mstb->lct / 2);
1429	hdr->seqno = txmsg->seqno;
1430	return 0;
1431}
1432/*
1433 * process a single block of the next message in the sideband queue
1434 */
1435static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
1436				   struct drm_dp_sideband_msg_tx *txmsg,
1437				   bool up)
1438{
1439	u8 chunk[48];
1440	struct drm_dp_sideband_msg_hdr hdr;
1441	int len, space, idx, tosend;
1442	int ret;
1443
1444	memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
1445
1446	if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED) {
1447		txmsg->seqno = -1;
1448		txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
1449	}
1450
1451	/* make hdr from dst mst - for replies use seqno
1452	   otherwise assign one */
1453	ret = set_hdr_from_dst_qlock(&hdr, txmsg);
1454	if (ret < 0)
1455		return ret;
1456
1457	/* amount left to send in this message */
1458	len = txmsg->cur_len - txmsg->cur_offset;
1459
1460	/* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
1461	space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
1462
1463	tosend = min(len, space);
1464	if (len == txmsg->cur_len)
1465		hdr.somt = 1;
1466	if (space >= len)
1467		hdr.eomt = 1;
1468
1469
1470	hdr.msg_len = tosend + 1;
1471	drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
1472	memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
1473	/* add crc at end */
1474	drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
1475	idx += tosend + 1;
1476
1477	ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
1478	if (ret) {
1479		DRM_DEBUG_KMS("sideband msg failed to send\n");
1480		return ret;
1481	}
1482
1483	txmsg->cur_offset += tosend;
1484	if (txmsg->cur_offset == txmsg->cur_len) {
1485		txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
1486		return 1;
1487	}
1488	return 0;
1489}
1490
1491static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
1492{
1493	struct drm_dp_sideband_msg_tx *txmsg;
1494	int ret;
1495
1496	WARN_ON(!mutex_is_locked(&mgr->qlock));
1497
1498	/* construct a chunk from the first msg in the tx_msg queue */
1499	if (list_empty(&mgr->tx_msg_downq))
1500		return;
1501
1502	txmsg = list_first_entry(&mgr->tx_msg_downq, struct drm_dp_sideband_msg_tx, next);
1503	ret = process_single_tx_qlock(mgr, txmsg, false);
1504	if (ret == 1) {
1505		/* txmsg is sent it should be in the slots now */
1506		list_del(&txmsg->next);
1507	} else if (ret) {
1508		DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
1509		list_del(&txmsg->next);
1510		if (txmsg->seqno != -1)
1511			txmsg->dst->tx_slots[txmsg->seqno] = NULL;
1512		txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
1513		wake_up(&mgr->tx_waitq);
1514	}
1515}
1516
1517/* called holding qlock */
1518static void process_single_up_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
1519				       struct drm_dp_sideband_msg_tx *txmsg)
1520{
1521	int ret;
1522
1523	/* construct a chunk from the first msg in the tx_msg queue */
1524	ret = process_single_tx_qlock(mgr, txmsg, true);
1525
1526	if (ret != 1)
1527		DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
1528
1529	txmsg->dst->tx_slots[txmsg->seqno] = NULL;
1530}
1531
1532static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
1533				 struct drm_dp_sideband_msg_tx *txmsg)
1534{
1535	mutex_lock(&mgr->qlock);
1536	list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
1537	if (list_is_singular(&mgr->tx_msg_downq))
1538		process_single_down_tx_qlock(mgr);
1539	mutex_unlock(&mgr->qlock);
1540}
1541
1542static void drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
1543				     struct drm_dp_mst_branch *mstb)
1544{
1545	int len;
1546	struct drm_dp_sideband_msg_tx *txmsg;
1547	int ret;
1548
1549	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1550	if (!txmsg)
1551		return;
1552
1553	txmsg->dst = mstb;
1554	len = build_link_address(txmsg);
1555
1556	mstb->link_address_sent = true;
1557	drm_dp_queue_down_tx(mgr, txmsg);
1558
1559	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1560	if (ret > 0) {
1561		int i;
1562
1563		if (txmsg->reply.reply_type == 1)
1564			DRM_DEBUG_KMS("link address nak received\n");
1565		else {
1566			DRM_DEBUG_KMS("link address reply: %d\n", txmsg->reply.u.link_addr.nports);
1567			for (i = 0; i < txmsg->reply.u.link_addr.nports; i++) {
1568				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,
1569				       txmsg->reply.u.link_addr.ports[i].input_port,
1570				       txmsg->reply.u.link_addr.ports[i].peer_device_type,
1571				       txmsg->reply.u.link_addr.ports[i].port_number,
1572				       txmsg->reply.u.link_addr.ports[i].dpcd_revision,
1573				       txmsg->reply.u.link_addr.ports[i].mcs,
1574				       txmsg->reply.u.link_addr.ports[i].ddps,
1575				       txmsg->reply.u.link_addr.ports[i].legacy_device_plug_status,
1576				       txmsg->reply.u.link_addr.ports[i].num_sdp_streams,
1577				       txmsg->reply.u.link_addr.ports[i].num_sdp_stream_sinks);
1578			}
1579
1580			drm_dp_check_mstb_guid(mstb, txmsg->reply.u.link_addr.guid);
1581
1582			for (i = 0; i < txmsg->reply.u.link_addr.nports; i++) {
1583				drm_dp_add_port(mstb, mgr->dev, &txmsg->reply.u.link_addr.ports[i]);
1584			}
1585			(*mgr->cbs->hotplug)(mgr);
1586		}
1587	} else {
1588		mstb->link_address_sent = false;
1589		DRM_DEBUG_KMS("link address failed %d\n", ret);
1590	}
1591
1592	kfree(txmsg);
1593}
1594
1595static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
1596					   struct drm_dp_mst_branch *mstb,
1597					   struct drm_dp_mst_port *port)
1598{
1599	int len;
1600	struct drm_dp_sideband_msg_tx *txmsg;
1601	int ret;
1602
1603	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1604	if (!txmsg)
1605		return -ENOMEM;
1606
1607	txmsg->dst = mstb;
1608	len = build_enum_path_resources(txmsg, port->port_num);
1609
1610	drm_dp_queue_down_tx(mgr, txmsg);
1611
1612	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1613	if (ret > 0) {
1614		if (txmsg->reply.reply_type == 1)
1615			DRM_DEBUG_KMS("enum path resources nak received\n");
1616		else {
1617			if (port->port_num != txmsg->reply.u.path_resources.port_number)
1618				DRM_ERROR("got incorrect port in response\n");
1619			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,
1620			       txmsg->reply.u.path_resources.avail_payload_bw_number);
1621			port->available_pbn = txmsg->reply.u.path_resources.avail_payload_bw_number;
1622		}
1623	}
1624
1625	kfree(txmsg);
1626	return 0;
1627}
1628
1629static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb)
1630{
1631	if (!mstb->port_parent)
1632		return NULL;
1633
1634	if (mstb->port_parent->mstb != mstb)
1635		return mstb->port_parent;
1636
1637	return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
1638}
1639
1640static struct drm_dp_mst_branch *drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
1641									 struct drm_dp_mst_branch *mstb,
1642									 int *port_num)
1643{
1644	struct drm_dp_mst_branch *rmstb = NULL;
1645	struct drm_dp_mst_port *found_port;
1646	mutex_lock(&mgr->lock);
1647	if (mgr->mst_primary) {
1648		found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
1649
1650		if (found_port) {
1651			rmstb = found_port->parent;
1652			kref_get(&rmstb->kref);
1653			*port_num = found_port->port_num;
1654		}
1655	}
1656	mutex_unlock(&mgr->lock);
1657	return rmstb;
1658}
1659
1660static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
1661				   struct drm_dp_mst_port *port,
1662				   int id,
1663				   int pbn)
1664{
1665	struct drm_dp_sideband_msg_tx *txmsg;
1666	struct drm_dp_mst_branch *mstb;
1667	int len, ret, port_num;
1668	u8 sinks[DRM_DP_MAX_SDP_STREAMS];
1669	int i;
1670
1671	port = drm_dp_get_validated_port_ref(mgr, port);
1672	if (!port)
1673		return -EINVAL;
1674
1675	port_num = port->port_num;
1676	mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
1677	if (!mstb) {
1678		mstb = drm_dp_get_last_connected_port_and_mstb(mgr, port->parent, &port_num);
1679
1680		if (!mstb) {
1681			drm_dp_put_port(port);
1682			return -EINVAL;
1683		}
1684	}
1685
1686	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1687	if (!txmsg) {
1688		ret = -ENOMEM;
1689		goto fail_put;
1690	}
1691
1692	for (i = 0; i < port->num_sdp_streams; i++)
1693		sinks[i] = i;
1694
1695	txmsg->dst = mstb;
1696	len = build_allocate_payload(txmsg, port_num,
1697				     id,
1698				     pbn, port->num_sdp_streams, sinks);
1699
1700	drm_dp_queue_down_tx(mgr, txmsg);
1701
1702	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1703	if (ret > 0) {
1704		if (txmsg->reply.reply_type == 1) {
1705			ret = -EINVAL;
1706		} else
1707			ret = 0;
1708	}
1709	kfree(txmsg);
1710fail_put:
1711	drm_dp_put_mst_branch_device(mstb);
1712	drm_dp_put_port(port);
1713	return ret;
1714}
1715
1716static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
1717				       int id,
1718				       struct drm_dp_payload *payload)
1719{
1720	int ret;
1721
1722	ret = drm_dp_dpcd_write_payload(mgr, id, payload);
1723	if (ret < 0) {
1724		payload->payload_state = 0;
1725		return ret;
1726	}
1727	payload->payload_state = DP_PAYLOAD_LOCAL;
1728	return 0;
1729}
1730
1731static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
1732				       struct drm_dp_mst_port *port,
1733				       int id,
1734				       struct drm_dp_payload *payload)
1735{
1736	int ret;
1737	ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
1738	if (ret < 0)
1739		return ret;
1740	payload->payload_state = DP_PAYLOAD_REMOTE;
1741	return ret;
1742}
1743
1744static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
1745					struct drm_dp_mst_port *port,
1746					int id,
1747					struct drm_dp_payload *payload)
1748{
1749	DRM_DEBUG_KMS("\n");
1750	/* its okay for these to fail */
1751	if (port) {
1752		drm_dp_payload_send_msg(mgr, port, id, 0);
1753	}
1754
1755	drm_dp_dpcd_write_payload(mgr, id, payload);
1756	payload->payload_state = DP_PAYLOAD_DELETE_LOCAL;
1757	return 0;
1758}
1759
1760static int drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
1761					int id,
1762					struct drm_dp_payload *payload)
1763{
1764	payload->payload_state = 0;
1765	return 0;
1766}
1767
1768/**
1769 * drm_dp_update_payload_part1() - Execute payload update part 1
1770 * @mgr: manager to use.
1771 *
1772 * This iterates over all proposed virtual channels, and tries to
1773 * allocate space in the link for them. For 0->slots transitions,
1774 * this step just writes the VCPI to the MST device. For slots->0
1775 * transitions, this writes the updated VCPIs and removes the
1776 * remote VC payloads.
1777 *
1778 * after calling this the driver should generate ACT and payload
1779 * packets.
1780 */
1781int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
1782{
1783	int i, j;
1784	int cur_slots = 1;
1785	struct drm_dp_payload req_payload;
1786	struct drm_dp_mst_port *port;
1787
1788	mutex_lock(&mgr->payload_lock);
1789	for (i = 0; i < mgr->max_payloads; i++) {
1790		/* solve the current payloads - compare to the hw ones
1791		   - update the hw view */
1792		req_payload.start_slot = cur_slots;
1793		if (mgr->proposed_vcpis[i]) {
1794			port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
1795			port = drm_dp_get_validated_port_ref(mgr, port);
1796			if (!port) {
1797				mutex_unlock(&mgr->payload_lock);
1798				return -EINVAL;
1799			}
1800			req_payload.num_slots = mgr->proposed_vcpis[i]->num_slots;
1801			req_payload.vcpi = mgr->proposed_vcpis[i]->vcpi;
1802		} else {
1803			port = NULL;
1804			req_payload.num_slots = 0;
1805		}
1806
1807		if (mgr->payloads[i].start_slot != req_payload.start_slot) {
1808			mgr->payloads[i].start_slot = req_payload.start_slot;
1809		}
1810		/* work out what is required to happen with this payload */
1811		if (mgr->payloads[i].num_slots != req_payload.num_slots) {
1812
1813			/* need to push an update for this payload */
1814			if (req_payload.num_slots) {
1815				drm_dp_create_payload_step1(mgr, mgr->proposed_vcpis[i]->vcpi, &req_payload);
1816				mgr->payloads[i].num_slots = req_payload.num_slots;
1817				mgr->payloads[i].vcpi = req_payload.vcpi;
1818			} else if (mgr->payloads[i].num_slots) {
1819				mgr->payloads[i].num_slots = 0;
1820				drm_dp_destroy_payload_step1(mgr, port, mgr->payloads[i].vcpi, &mgr->payloads[i]);
1821				req_payload.payload_state = mgr->payloads[i].payload_state;
1822				mgr->payloads[i].start_slot = 0;
1823			}
1824			mgr->payloads[i].payload_state = req_payload.payload_state;
1825		}
1826		cur_slots += req_payload.num_slots;
1827
1828		if (port)
1829			drm_dp_put_port(port);
1830	}
1831
1832	for (i = 0; i < mgr->max_payloads; i++) {
1833		if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
1834			DRM_DEBUG_KMS("removing payload %d\n", i);
1835			for (j = i; j < mgr->max_payloads - 1; j++) {
1836				memcpy(&mgr->payloads[j], &mgr->payloads[j + 1], sizeof(struct drm_dp_payload));
1837				mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
1838				if (mgr->proposed_vcpis[j] && mgr->proposed_vcpis[j]->num_slots) {
1839					set_bit(j + 1, &mgr->payload_mask);
1840				} else {
1841					clear_bit(j + 1, &mgr->payload_mask);
1842				}
1843			}
1844			memset(&mgr->payloads[mgr->max_payloads - 1], 0, sizeof(struct drm_dp_payload));
1845			mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
1846			clear_bit(mgr->max_payloads, &mgr->payload_mask);
1847
1848		}
1849	}
1850	mutex_unlock(&mgr->payload_lock);
1851
1852	return 0;
1853}
1854EXPORT_SYMBOL(drm_dp_update_payload_part1);
1855
1856/**
1857 * drm_dp_update_payload_part2() - Execute payload update part 2
1858 * @mgr: manager to use.
1859 *
1860 * This iterates over all proposed virtual channels, and tries to
1861 * allocate space in the link for them. For 0->slots transitions,
1862 * this step writes the remote VC payload commands. For slots->0
1863 * this just resets some internal state.
1864 */
1865int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
1866{
1867	struct drm_dp_mst_port *port;
1868	int i;
1869	int ret = 0;
1870	mutex_lock(&mgr->payload_lock);
1871	for (i = 0; i < mgr->max_payloads; i++) {
1872
1873		if (!mgr->proposed_vcpis[i])
1874			continue;
1875
1876		port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
1877
1878		DRM_DEBUG_KMS("payload %d %d\n", i, mgr->payloads[i].payload_state);
1879		if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
1880			ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
1881		} else if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
1882			ret = drm_dp_destroy_payload_step2(mgr, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
1883		}
1884		if (ret) {
1885			mutex_unlock(&mgr->payload_lock);
1886			return ret;
1887		}
1888	}
1889	mutex_unlock(&mgr->payload_lock);
1890	return 0;
1891}
1892EXPORT_SYMBOL(drm_dp_update_payload_part2);
1893
1894#if 0 /* unused as of yet */
1895static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
1896				 struct drm_dp_mst_port *port,
1897				 int offset, int size)
1898{
1899	int len;
1900	struct drm_dp_sideband_msg_tx *txmsg;
1901
1902	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1903	if (!txmsg)
1904		return -ENOMEM;
1905
1906	len = build_dpcd_read(txmsg, port->port_num, 0, 8);
1907	txmsg->dst = port->parent;
1908
1909	drm_dp_queue_down_tx(mgr, txmsg);
1910
1911	return 0;
1912}
1913#endif
1914
1915static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
1916				  struct drm_dp_mst_port *port,
1917				  int offset, int size, u8 *bytes)
1918{
1919	int len;
1920	int ret;
1921	struct drm_dp_sideband_msg_tx *txmsg;
1922	struct drm_dp_mst_branch *mstb;
1923
1924	mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
1925	if (!mstb)
1926		return -EINVAL;
1927
1928	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1929	if (!txmsg) {
1930		ret = -ENOMEM;
1931		goto fail_put;
1932	}
1933
1934	len = build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
1935	txmsg->dst = mstb;
1936
1937	drm_dp_queue_down_tx(mgr, txmsg);
1938
1939	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1940	if (ret > 0) {
1941		if (txmsg->reply.reply_type == 1) {
1942			ret = -EINVAL;
1943		} else
1944			ret = 0;
1945	}
1946	kfree(txmsg);
1947fail_put:
1948	drm_dp_put_mst_branch_device(mstb);
1949	return ret;
1950}
1951
1952static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
1953{
1954	struct drm_dp_sideband_msg_reply_body reply;
1955
1956	reply.reply_type = 0;
1957	reply.req_type = req_type;
1958	drm_dp_encode_sideband_reply(&reply, msg);
1959	return 0;
1960}
1961
1962static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
1963				    struct drm_dp_mst_branch *mstb,
1964				    int req_type, int seqno, bool broadcast)
1965{
1966	struct drm_dp_sideband_msg_tx *txmsg;
1967
1968	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1969	if (!txmsg)
1970		return -ENOMEM;
1971
1972	txmsg->dst = mstb;
1973	txmsg->seqno = seqno;
1974	drm_dp_encode_up_ack_reply(txmsg, req_type);
1975
1976	mutex_lock(&mgr->qlock);
1977
1978	process_single_up_tx_qlock(mgr, txmsg);
1979
1980	mutex_unlock(&mgr->qlock);
1981
1982	kfree(txmsg);
1983	return 0;
1984}
1985
1986static bool drm_dp_get_vc_payload_bw(int dp_link_bw,
1987				     int dp_link_count,
1988				     int *out)
1989{
1990	switch (dp_link_bw) {
1991	default:
1992		DRM_DEBUG_KMS("invalid link bandwidth in DPCD: %x (link count: %d)\n",
1993			      dp_link_bw, dp_link_count);
1994		return false;
1995
1996	case DP_LINK_BW_1_62:
1997		*out = 3 * dp_link_count;
1998		break;
1999	case DP_LINK_BW_2_7:
2000		*out = 5 * dp_link_count;
2001		break;
2002	case DP_LINK_BW_5_4:
2003		*out = 10 * dp_link_count;
2004		break;
2005	}
2006	return true;
2007}
2008
2009/**
2010 * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
2011 * @mgr: manager to set state for
2012 * @mst_state: true to enable MST on this connector - false to disable.
2013 *
2014 * This is called by the driver when it detects an MST capable device plugged
2015 * into a DP MST capable port, or when a DP MST capable device is unplugged.
2016 */
2017int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
2018{
2019	int ret = 0;
2020	struct drm_dp_mst_branch *mstb = NULL;
2021
2022	mutex_lock(&mgr->lock);
2023	if (mst_state == mgr->mst_state)
2024		goto out_unlock;
2025
2026	mgr->mst_state = mst_state;
2027	/* set the device into MST mode */
2028	if (mst_state) {
2029		WARN_ON(mgr->mst_primary);
2030
2031		/* get dpcd info */
2032		ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, DP_RECEIVER_CAP_SIZE);
2033		if (ret != DP_RECEIVER_CAP_SIZE) {
2034			DRM_DEBUG_KMS("failed to read DPCD\n");
2035			goto out_unlock;
2036		}
2037
2038		if (!drm_dp_get_vc_payload_bw(mgr->dpcd[1],
2039					      mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK,
2040					      &mgr->pbn_div)) {
2041			ret = -EINVAL;
2042			goto out_unlock;
2043		}
2044
2045		mgr->total_pbn = 2560;
2046		mgr->total_slots = DIV_ROUND_UP(mgr->total_pbn, mgr->pbn_div);
2047		mgr->avail_slots = mgr->total_slots;
2048
2049		/* add initial branch device at LCT 1 */
2050		mstb = drm_dp_add_mst_branch_device(1, NULL);
2051		if (mstb == NULL) {
2052			ret = -ENOMEM;
2053			goto out_unlock;
2054		}
2055		mstb->mgr = mgr;
2056
2057		/* give this the main reference */
2058		mgr->mst_primary = mstb;
2059		kref_get(&mgr->mst_primary->kref);
2060
2061		ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2062							 DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC);
2063		if (ret < 0) {
2064			goto out_unlock;
2065		}
2066
2067		{
2068			struct drm_dp_payload reset_pay;
2069			reset_pay.start_slot = 0;
2070			reset_pay.num_slots = 0x3f;
2071			drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
2072		}
2073
2074		queue_work(system_long_wq, &mgr->work);
2075
2076		ret = 0;
2077	} else {
2078		/* disable MST on the device */
2079		mstb = mgr->mst_primary;
2080		mgr->mst_primary = NULL;
2081		/* this can fail if the device is gone */
2082		drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
2083		ret = 0;
2084		memset(mgr->payloads, 0, mgr->max_payloads * sizeof(struct drm_dp_payload));
2085		mgr->payload_mask = 0;
2086		set_bit(0, &mgr->payload_mask);
2087		mgr->vcpi_mask = 0;
2088	}
2089
2090out_unlock:
2091	mutex_unlock(&mgr->lock);
2092	if (mstb)
2093		drm_dp_put_mst_branch_device(mstb);
2094	return ret;
2095
2096}
2097EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
2098
2099/**
2100 * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
2101 * @mgr: manager to suspend
2102 *
2103 * This function tells the MST device that we can't handle UP messages
2104 * anymore. This should stop it from sending any since we are suspended.
2105 */
2106void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
2107{
2108	mutex_lock(&mgr->lock);
2109	drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2110			   DP_MST_EN | DP_UPSTREAM_IS_SRC);
2111	mutex_unlock(&mgr->lock);
2112	flush_work(&mgr->work);
2113	flush_work(&mgr->destroy_connector_work);
2114}
2115EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
2116
2117/**
2118 * drm_dp_mst_topology_mgr_resume() - resume the MST manager
2119 * @mgr: manager to resume
2120 *
2121 * This will fetch DPCD and see if the device is still there,
2122 * if it is, it will rewrite the MSTM control bits, and return.
2123 *
2124 * if the device fails this returns -1, and the driver should do
2125 * a full MST reprobe, in case we were undocked.
2126 */
2127int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr)
2128{
2129	int ret = 0;
2130
2131	mutex_lock(&mgr->lock);
2132
2133	if (mgr->mst_primary) {
2134		int sret;
2135		u8 guid[16];
2136
2137		sret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, DP_RECEIVER_CAP_SIZE);
2138		if (sret != DP_RECEIVER_CAP_SIZE) {
2139			DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
2140			ret = -1;
2141			goto out_unlock;
2142		}
2143
2144		ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2145					 DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC);
2146		if (ret < 0) {
2147			DRM_DEBUG_KMS("mst write failed - undocked during suspend?\n");
2148			ret = -1;
2149			goto out_unlock;
2150		}
2151
2152		/* Some hubs forget their guids after they resume */
2153		sret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
2154		if (sret != 16) {
2155			DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
2156			ret = -1;
2157			goto out_unlock;
2158		}
2159		drm_dp_check_mstb_guid(mgr->mst_primary, guid);
2160
2161		ret = 0;
2162	} else
2163		ret = -1;
2164
2165out_unlock:
2166	mutex_unlock(&mgr->lock);
2167	return ret;
2168}
2169EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
2170
2171static void drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up)
2172{
2173	int len;
2174	u8 replyblock[32];
2175	int replylen, origlen, curreply;
2176	int ret;
2177	struct drm_dp_sideband_msg_rx *msg;
2178	int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE : DP_SIDEBAND_MSG_DOWN_REP_BASE;
2179	msg = up ? &mgr->up_req_recv : &mgr->down_rep_recv;
2180
2181	len = min(mgr->max_dpcd_transaction_bytes, 16);
2182	ret = drm_dp_dpcd_read(mgr->aux, basereg,
2183			       replyblock, len);
2184	if (ret != len) {
2185		DRM_DEBUG_KMS("failed to read DPCD down rep %d %d\n", len, ret);
2186		return;
2187	}
2188	ret = drm_dp_sideband_msg_build(msg, replyblock, len, true);
2189	if (!ret) {
2190		DRM_DEBUG_KMS("sideband msg build failed %d\n", replyblock[0]);
2191		return;
2192	}
2193	replylen = msg->curchunk_len + msg->curchunk_hdrlen;
2194
2195	origlen = replylen;
2196	replylen -= len;
2197	curreply = len;
2198	while (replylen > 0) {
2199		len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
2200		ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
2201				    replyblock, len);
2202		if (ret != len) {
2203			DRM_DEBUG_KMS("failed to read a chunk\n");
2204		}
2205		ret = drm_dp_sideband_msg_build(msg, replyblock, len, false);
2206		if (ret == false)
2207			DRM_DEBUG_KMS("failed to build sideband msg\n");
2208		curreply += len;
2209		replylen -= len;
2210	}
2211}
2212
2213static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
2214{
2215	int ret = 0;
2216
2217	drm_dp_get_one_sb_msg(mgr, false);
2218
2219	if (mgr->down_rep_recv.have_eomt) {
2220		struct drm_dp_sideband_msg_tx *txmsg;
2221		struct drm_dp_mst_branch *mstb;
2222		int slot = -1;
2223		mstb = drm_dp_get_mst_branch_device(mgr,
2224						    mgr->down_rep_recv.initial_hdr.lct,
2225						    mgr->down_rep_recv.initial_hdr.rad);
2226
2227		if (!mstb) {
2228			DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->down_rep_recv.initial_hdr.lct);
2229			memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2230			return 0;
2231		}
2232
2233		/* find the message */
2234		slot = mgr->down_rep_recv.initial_hdr.seqno;
2235		mutex_lock(&mgr->qlock);
2236		txmsg = mstb->tx_slots[slot];
2237		/* remove from slots */
2238		mutex_unlock(&mgr->qlock);
2239
2240		if (!txmsg) {
2241			DRM_DEBUG_KMS("Got MST reply with no msg %p %d %d %02x %02x\n",
2242			       mstb,
2243			       mgr->down_rep_recv.initial_hdr.seqno,
2244			       mgr->down_rep_recv.initial_hdr.lct,
2245				      mgr->down_rep_recv.initial_hdr.rad[0],
2246				      mgr->down_rep_recv.msg[0]);
2247			drm_dp_put_mst_branch_device(mstb);
2248			memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2249			return 0;
2250		}
2251
2252		drm_dp_sideband_parse_reply(&mgr->down_rep_recv, &txmsg->reply);
2253		if (txmsg->reply.reply_type == 1) {
2254			DRM_DEBUG_KMS("Got NAK reply: req 0x%02x, reason 0x%02x, nak data 0x%02x\n", txmsg->reply.req_type, txmsg->reply.u.nak.reason, txmsg->reply.u.nak.nak_data);
2255		}
2256
2257		memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2258		drm_dp_put_mst_branch_device(mstb);
2259
2260		mutex_lock(&mgr->qlock);
2261		txmsg->state = DRM_DP_SIDEBAND_TX_RX;
2262		mstb->tx_slots[slot] = NULL;
2263		mutex_unlock(&mgr->qlock);
2264
2265		wake_up(&mgr->tx_waitq);
2266	}
2267	return ret;
2268}
2269
2270static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
2271{
2272	int ret = 0;
2273	drm_dp_get_one_sb_msg(mgr, true);
2274
2275	if (mgr->up_req_recv.have_eomt) {
2276		struct drm_dp_sideband_msg_req_body msg;
2277		struct drm_dp_mst_branch *mstb = NULL;
2278		bool seqno;
2279
2280		if (!mgr->up_req_recv.initial_hdr.broadcast) {
2281			mstb = drm_dp_get_mst_branch_device(mgr,
2282							    mgr->up_req_recv.initial_hdr.lct,
2283							    mgr->up_req_recv.initial_hdr.rad);
2284			if (!mstb) {
2285				DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
2286				memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2287				return 0;
2288			}
2289		}
2290
2291		seqno = mgr->up_req_recv.initial_hdr.seqno;
2292		drm_dp_sideband_parse_req(&mgr->up_req_recv, &msg);
2293
2294		if (msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
2295			drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, msg.req_type, seqno, false);
2296
2297			if (!mstb)
2298				mstb = drm_dp_get_mst_branch_device_by_guid(mgr, msg.u.conn_stat.guid);
2299
2300			if (!mstb) {
2301				DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
2302				memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2303				return 0;
2304			}
2305
2306			drm_dp_update_port(mstb, &msg.u.conn_stat);
2307
2308			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);
2309			(*mgr->cbs->hotplug)(mgr);
2310
2311		} else if (msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
2312			drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, msg.req_type, seqno, false);
2313			if (!mstb)
2314				mstb = drm_dp_get_mst_branch_device_by_guid(mgr, msg.u.resource_stat.guid);
2315
2316			if (!mstb) {
2317				DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
2318				memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2319				return 0;
2320			}
2321
2322			DRM_DEBUG_KMS("Got RSN: pn: %d avail_pbn %d\n", msg.u.resource_stat.port_number, msg.u.resource_stat.available_pbn);
2323		}
2324
2325		drm_dp_put_mst_branch_device(mstb);
2326		memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2327	}
2328	return ret;
2329}
2330
2331/**
2332 * drm_dp_mst_hpd_irq() - MST hotplug IRQ notify
2333 * @mgr: manager to notify irq for.
2334 * @esi: 4 bytes from SINK_COUNT_ESI
2335 * @handled: whether the hpd interrupt was consumed or not
2336 *
2337 * This should be called from the driver when it detects a short IRQ,
2338 * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
2339 * topology manager will process the sideband messages received as a result
2340 * of this.
2341 */
2342int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled)
2343{
2344	int ret = 0;
2345	int sc;
2346	*handled = false;
2347	sc = esi[0] & 0x3f;
2348
2349	if (sc != mgr->sink_count) {
2350		mgr->sink_count = sc;
2351		*handled = true;
2352	}
2353
2354	if (esi[1] & DP_DOWN_REP_MSG_RDY) {
2355		ret = drm_dp_mst_handle_down_rep(mgr);
2356		*handled = true;
2357	}
2358
2359	if (esi[1] & DP_UP_REQ_MSG_RDY) {
2360		ret |= drm_dp_mst_handle_up_req(mgr);
2361		*handled = true;
2362	}
2363
2364	drm_dp_mst_kick_tx(mgr);
2365	return ret;
2366}
2367EXPORT_SYMBOL(drm_dp_mst_hpd_irq);
2368
2369/**
2370 * drm_dp_mst_detect_port() - get connection status for an MST port
2371 * @connector: DRM connector for this port
2372 * @mgr: manager for this port
2373 * @port: unverified pointer to a port
2374 *
2375 * This returns the current connection state for a port. It validates the
2376 * port pointer still exists so the caller doesn't require a reference
2377 */
2378enum drm_connector_status drm_dp_mst_detect_port(struct drm_connector *connector,
2379						 struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2380{
2381	enum drm_connector_status status = connector_status_disconnected;
2382
2383	/* we need to search for the port in the mgr in case its gone */
2384	port = drm_dp_get_validated_port_ref(mgr, port);
2385	if (!port)
2386		return connector_status_disconnected;
2387
2388	if (!port->ddps)
2389		goto out;
2390
2391	switch (port->pdt) {
2392	case DP_PEER_DEVICE_NONE:
2393	case DP_PEER_DEVICE_MST_BRANCHING:
2394		break;
2395
2396	case DP_PEER_DEVICE_SST_SINK:
2397		status = connector_status_connected;
2398		/* for logical ports - cache the EDID */
2399		if (port->port_num >= 8 && !port->cached_edid) {
2400			port->cached_edid = drm_get_edid(connector, &port->aux.ddc);
2401		}
2402		break;
2403	case DP_PEER_DEVICE_DP_LEGACY_CONV:
2404		if (port->ldps)
2405			status = connector_status_connected;
2406		break;
2407	}
2408out:
2409	drm_dp_put_port(port);
2410	return status;
2411}
2412EXPORT_SYMBOL(drm_dp_mst_detect_port);
2413
2414/**
2415 * drm_dp_mst_port_has_audio() - Check whether port has audio capability or not
2416 * @mgr: manager for this port
2417 * @port: unverified pointer to a port.
2418 *
2419 * This returns whether the port supports audio or not.
2420 */
2421bool drm_dp_mst_port_has_audio(struct drm_dp_mst_topology_mgr *mgr,
2422					struct drm_dp_mst_port *port)
2423{
2424	bool ret = false;
2425
2426	port = drm_dp_get_validated_port_ref(mgr, port);
2427	if (!port)
2428		return ret;
2429	ret = port->has_audio;
2430	drm_dp_put_port(port);
2431	return ret;
2432}
2433EXPORT_SYMBOL(drm_dp_mst_port_has_audio);
2434
2435/**
2436 * drm_dp_mst_get_edid() - get EDID for an MST port
2437 * @connector: toplevel connector to get EDID for
2438 * @mgr: manager for this port
2439 * @port: unverified pointer to a port.
2440 *
2441 * This returns an EDID for the port connected to a connector,
2442 * It validates the pointer still exists so the caller doesn't require a
2443 * reference.
2444 */
2445struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2446{
2447	struct edid *edid = NULL;
2448
2449	/* we need to search for the port in the mgr in case its gone */
2450	port = drm_dp_get_validated_port_ref(mgr, port);
2451	if (!port)
2452		return NULL;
2453
2454	if (port->cached_edid)
2455		edid = drm_edid_duplicate(port->cached_edid);
2456	else {
2457		edid = drm_get_edid(connector, &port->aux.ddc);
2458		drm_mode_connector_set_tile_property(connector);
2459	}
2460	port->has_audio = drm_detect_monitor_audio(edid);
2461	drm_dp_put_port(port);
2462	return edid;
2463}
2464EXPORT_SYMBOL(drm_dp_mst_get_edid);
2465
2466/**
2467 * drm_dp_find_vcpi_slots() - find slots for this PBN value
2468 * @mgr: manager to use
2469 * @pbn: payload bandwidth to convert into slots.
2470 */
2471int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
2472			   int pbn)
2473{
2474	int num_slots;
2475
2476	num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
2477
2478	if (num_slots > mgr->avail_slots)
2479		return -ENOSPC;
2480	return num_slots;
2481}
2482EXPORT_SYMBOL(drm_dp_find_vcpi_slots);
2483
2484static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
2485			    struct drm_dp_vcpi *vcpi, int pbn)
2486{
2487	int num_slots;
2488	int ret;
2489
2490	num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
2491
2492	if (num_slots > mgr->avail_slots)
2493		return -ENOSPC;
2494
2495	vcpi->pbn = pbn;
2496	vcpi->aligned_pbn = num_slots * mgr->pbn_div;
2497	vcpi->num_slots = num_slots;
2498
2499	ret = drm_dp_mst_assign_payload_id(mgr, vcpi);
2500	if (ret < 0)
2501		return ret;
2502	return 0;
2503}
2504
2505/**
2506 * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
2507 * @mgr: manager for this port
2508 * @port: port to allocate a virtual channel for.
2509 * @pbn: payload bandwidth number to request
2510 * @slots: returned number of slots for this PBN.
2511 */
2512bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, int pbn, int *slots)
2513{
2514	int ret;
2515
2516	port = drm_dp_get_validated_port_ref(mgr, port);
2517	if (!port)
2518		return false;
2519
2520	if (port->vcpi.vcpi > 0) {
2521		DRM_DEBUG_KMS("payload: vcpi %d already allocated for pbn %d - requested pbn %d\n", port->vcpi.vcpi, port->vcpi.pbn, pbn);
2522		if (pbn == port->vcpi.pbn) {
2523			*slots = port->vcpi.num_slots;
2524			drm_dp_put_port(port);
2525			return true;
2526		}
2527	}
2528
2529	ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn);
2530	if (ret) {
2531		DRM_DEBUG_KMS("failed to init vcpi %d %d %d\n", DIV_ROUND_UP(pbn, mgr->pbn_div), mgr->avail_slots, ret);
2532		goto out;
2533	}
2534	DRM_DEBUG_KMS("initing vcpi for %d %d\n", pbn, port->vcpi.num_slots);
2535	*slots = port->vcpi.num_slots;
2536
2537	drm_dp_put_port(port);
2538	return true;
2539out:
2540	return false;
2541}
2542EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
2543
2544int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2545{
2546	int slots = 0;
2547	port = drm_dp_get_validated_port_ref(mgr, port);
2548	if (!port)
2549		return slots;
2550
2551	slots = port->vcpi.num_slots;
2552	drm_dp_put_port(port);
2553	return slots;
2554}
2555EXPORT_SYMBOL(drm_dp_mst_get_vcpi_slots);
2556
2557/**
2558 * drm_dp_mst_reset_vcpi_slots() - Reset number of slots to 0 for VCPI
2559 * @mgr: manager for this port
2560 * @port: unverified pointer to a port.
2561 *
2562 * This just resets the number of slots for the ports VCPI for later programming.
2563 */
2564void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2565{
2566	port = drm_dp_get_validated_port_ref(mgr, port);
2567	if (!port)
2568		return;
2569	port->vcpi.num_slots = 0;
2570	drm_dp_put_port(port);
2571}
2572EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
2573
2574/**
2575 * drm_dp_mst_deallocate_vcpi() - deallocate a VCPI
2576 * @mgr: manager for this port
2577 * @port: unverified port to deallocate vcpi for
2578 */
2579void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2580{
2581	port = drm_dp_get_validated_port_ref(mgr, port);
2582	if (!port)
2583		return;
2584
2585	drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
2586	port->vcpi.num_slots = 0;
2587	port->vcpi.pbn = 0;
2588	port->vcpi.aligned_pbn = 0;
2589	port->vcpi.vcpi = 0;
2590	drm_dp_put_port(port);
2591}
2592EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
2593
2594static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
2595				     int id, struct drm_dp_payload *payload)
2596{
2597	u8 payload_alloc[3], status;
2598	int ret;
2599	int retries = 0;
2600
2601	drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
2602			   DP_PAYLOAD_TABLE_UPDATED);
2603
2604	payload_alloc[0] = id;
2605	payload_alloc[1] = payload->start_slot;
2606	payload_alloc[2] = payload->num_slots;
2607
2608	ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
2609	if (ret != 3) {
2610		DRM_DEBUG_KMS("failed to write payload allocation %d\n", ret);
2611		goto fail;
2612	}
2613
2614retry:
2615	ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
2616	if (ret < 0) {
2617		DRM_DEBUG_KMS("failed to read payload table status %d\n", ret);
2618		goto fail;
2619	}
2620
2621	if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
2622		retries++;
2623		if (retries < 20) {
2624			usleep_range(10000, 20000);
2625			goto retry;
2626		}
2627		DRM_DEBUG_KMS("status not set after read payload table status %d\n", status);
2628		ret = -EINVAL;
2629		goto fail;
2630	}
2631	ret = 0;
2632fail:
2633	return ret;
2634}
2635
2636
2637/**
2638 * drm_dp_check_act_status() - Check ACT handled status.
2639 * @mgr: manager to use
2640 *
2641 * Check the payload status bits in the DPCD for ACT handled completion.
2642 */
2643int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
2644{
2645	u8 status;
2646	int ret;
2647	int count = 0;
2648
2649	do {
2650		ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
2651
2652		if (ret < 0) {
2653			DRM_DEBUG_KMS("failed to read payload table status %d\n", ret);
2654			goto fail;
2655		}
2656
2657		if (status & DP_PAYLOAD_ACT_HANDLED)
2658			break;
2659		count++;
2660		udelay(100);
2661
2662	} while (count < 30);
2663
2664	if (!(status & DP_PAYLOAD_ACT_HANDLED)) {
2665		DRM_DEBUG_KMS("failed to get ACT bit %d after %d retries\n", status, count);
2666		ret = -EINVAL;
2667		goto fail;
2668	}
2669	return 0;
2670fail:
2671	return ret;
2672}
2673EXPORT_SYMBOL(drm_dp_check_act_status);
2674
2675/**
2676 * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
2677 * @clock: dot clock for the mode
2678 * @bpp: bpp for the mode.
2679 *
2680 * This uses the formula in the spec to calculate the PBN value for a mode.
2681 */
2682int drm_dp_calc_pbn_mode(int clock, int bpp)
2683{
2684	u64 kbps;
2685	s64 peak_kbps;
2686	u32 numerator;
2687	u32 denominator;
2688
2689	kbps = clock * bpp;
2690
2691	/*
2692	 * margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006
2693	 * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on
2694	 * common multiplier to render an integer PBN for all link rate/lane
2695	 * counts combinations
2696	 * calculate
2697	 * peak_kbps *= (1006/1000)
2698	 * peak_kbps *= (64/54)
2699	 * peak_kbps *= 8    convert to bytes
2700	 */
2701
2702	numerator = 64 * 1006;
2703	denominator = 54 * 8 * 1000 * 1000;
2704
2705	kbps *= numerator;
2706	peak_kbps = drm_fixp_from_fraction(kbps, denominator);
2707
2708	return drm_fixp2int_ceil(peak_kbps);
2709}
2710EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
2711
2712static int test_calc_pbn_mode(void)
2713{
2714	int ret;
2715	ret = drm_dp_calc_pbn_mode(154000, 30);
2716	if (ret != 689) {
2717		DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n",
2718				154000, 30, 689, ret);
2719		return -EINVAL;
2720	}
2721	ret = drm_dp_calc_pbn_mode(234000, 30);
2722	if (ret != 1047) {
2723		DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n",
2724				234000, 30, 1047, ret);
2725		return -EINVAL;
2726	}
2727	ret = drm_dp_calc_pbn_mode(297000, 24);
2728	if (ret != 1063) {
2729		DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n",
2730				297000, 24, 1063, ret);
2731		return -EINVAL;
2732	}
2733	return 0;
2734}
2735
2736/* we want to kick the TX after we've ack the up/down IRQs. */
2737static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
2738{
2739	queue_work(system_long_wq, &mgr->tx_work);
2740}
2741
2742static void drm_dp_mst_dump_mstb(struct seq_file *m,
2743				 struct drm_dp_mst_branch *mstb)
2744{
2745	struct drm_dp_mst_port *port;
2746	int tabs = mstb->lct;
2747	char prefix[10];
2748	int i;
2749
2750	for (i = 0; i < tabs; i++)
2751		prefix[i] = '\t';
2752	prefix[i] = '\0';
2753
2754	seq_printf(m, "%smst: %p, %d\n", prefix, mstb, mstb->num_ports);
2755	list_for_each_entry(port, &mstb->ports, next) {
2756		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);
2757		if (port->mstb)
2758			drm_dp_mst_dump_mstb(m, port->mstb);
2759	}
2760}
2761
2762static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
2763				  char *buf)
2764{
2765	int ret;
2766	int i;
2767	for (i = 0; i < 4; i++) {
2768		ret = drm_dp_dpcd_read(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS + (i * 16), &buf[i * 16], 16);
2769		if (ret != 16)
2770			break;
2771	}
2772	if (i == 4)
2773		return true;
2774	return false;
2775}
2776
2777static void fetch_monitor_name(struct drm_dp_mst_topology_mgr *mgr,
2778			       struct drm_dp_mst_port *port, char *name,
2779			       int namelen)
2780{
2781	struct edid *mst_edid;
2782
2783	mst_edid = drm_dp_mst_get_edid(port->connector, mgr, port);
2784	drm_edid_get_monitor_name(mst_edid, name, namelen);
2785}
2786
2787/**
2788 * drm_dp_mst_dump_topology(): dump topology to seq file.
2789 * @m: seq_file to dump output to
2790 * @mgr: manager to dump current topology for.
2791 *
2792 * helper to dump MST topology to a seq file for debugfs.
2793 */
2794void drm_dp_mst_dump_topology(struct seq_file *m,
2795			      struct drm_dp_mst_topology_mgr *mgr)
2796{
2797	int i;
2798	struct drm_dp_mst_port *port;
2799
2800	mutex_lock(&mgr->lock);
2801	if (mgr->mst_primary)
2802		drm_dp_mst_dump_mstb(m, mgr->mst_primary);
2803
2804	/* dump VCPIs */
2805	mutex_unlock(&mgr->lock);
2806
2807	mutex_lock(&mgr->payload_lock);
2808	seq_printf(m, "vcpi: %lx %lx %d\n", mgr->payload_mask, mgr->vcpi_mask,
2809		mgr->max_payloads);
2810
2811	for (i = 0; i < mgr->max_payloads; i++) {
2812		if (mgr->proposed_vcpis[i]) {
2813			char name[14];
2814
2815			port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
2816			fetch_monitor_name(mgr, port, name, sizeof(name));
2817			seq_printf(m, "vcpi %d: %d %d %d sink name: %s\n", i,
2818				   port->port_num, port->vcpi.vcpi,
2819				   port->vcpi.num_slots,
2820				   (*name != 0) ? name :  "Unknown");
2821		} else
2822			seq_printf(m, "vcpi %d:unused\n", i);
2823	}
2824	for (i = 0; i < mgr->max_payloads; i++) {
2825		seq_printf(m, "payload %d: %d, %d, %d\n",
2826			   i,
2827			   mgr->payloads[i].payload_state,
2828			   mgr->payloads[i].start_slot,
2829			   mgr->payloads[i].num_slots);
2830
2831
2832	}
2833	mutex_unlock(&mgr->payload_lock);
2834
2835	mutex_lock(&mgr->lock);
2836	if (mgr->mst_primary) {
2837		u8 buf[64];
2838		bool bret;
2839		int ret;
2840		ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, buf, DP_RECEIVER_CAP_SIZE);
2841		seq_printf(m, "dpcd: ");
2842		for (i = 0; i < DP_RECEIVER_CAP_SIZE; i++)
2843			seq_printf(m, "%02x ", buf[i]);
2844		seq_printf(m, "\n");
2845		ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
2846		seq_printf(m, "faux/mst: ");
2847		for (i = 0; i < 2; i++)
2848			seq_printf(m, "%02x ", buf[i]);
2849		seq_printf(m, "\n");
2850		ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
2851		seq_printf(m, "mst ctrl: ");
2852		for (i = 0; i < 1; i++)
2853			seq_printf(m, "%02x ", buf[i]);
2854		seq_printf(m, "\n");
2855
2856		/* dump the standard OUI branch header */
2857		ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
2858		seq_printf(m, "branch oui: ");
2859		for (i = 0; i < 0x3; i++)
2860			seq_printf(m, "%02x", buf[i]);
2861		seq_printf(m, " devid: ");
2862		for (i = 0x3; i < 0x8 && buf[i]; i++)
2863			seq_printf(m, "%c", buf[i]);
2864
2865		seq_printf(m, " revision: hw: %x.%x sw: %x.%x", buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]);
2866		seq_printf(m, "\n");
2867		bret = dump_dp_payload_table(mgr, buf);
2868		if (bret == true) {
2869			seq_printf(m, "payload table: ");
2870			for (i = 0; i < 63; i++)
2871				seq_printf(m, "%02x ", buf[i]);
2872			seq_printf(m, "\n");
2873		}
2874
2875	}
2876
2877	mutex_unlock(&mgr->lock);
2878
2879}
2880EXPORT_SYMBOL(drm_dp_mst_dump_topology);
2881
2882static void drm_dp_tx_work(struct work_struct *work)
2883{
2884	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
2885
2886	mutex_lock(&mgr->qlock);
2887	if (!list_empty(&mgr->tx_msg_downq))
2888		process_single_down_tx_qlock(mgr);
2889	mutex_unlock(&mgr->qlock);
2890}
2891
2892static void drm_dp_free_mst_port(struct kref *kref)
2893{
2894	struct drm_dp_mst_port *port = container_of(kref, struct drm_dp_mst_port, kref);
2895	kref_put(&port->parent->kref, drm_dp_free_mst_branch_device);
2896	kfree(port);
2897}
2898
2899static void drm_dp_destroy_connector_work(struct work_struct *work)
2900{
2901	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, destroy_connector_work);
2902	struct drm_dp_mst_port *port;
2903	bool send_hotplug = false;
2904	/*
2905	 * Not a regular list traverse as we have to drop the destroy
2906	 * connector lock before destroying the connector, to avoid AB->BA
2907	 * ordering between this lock and the config mutex.
2908	 */
2909	for (;;) {
2910		mutex_lock(&mgr->destroy_connector_lock);
2911		port = list_first_entry_or_null(&mgr->destroy_connector_list, struct drm_dp_mst_port, next);
2912		if (!port) {
2913			mutex_unlock(&mgr->destroy_connector_lock);
2914			break;
2915		}
2916		list_del(&port->next);
2917		mutex_unlock(&mgr->destroy_connector_lock);
2918
2919		kref_init(&port->kref);
2920		INIT_LIST_HEAD(&port->next);
2921
2922		mgr->cbs->destroy_connector(mgr, port->connector);
2923
2924		drm_dp_port_teardown_pdt(port, port->pdt);
2925		port->pdt = DP_PEER_DEVICE_NONE;
2926
2927		if (!port->input && port->vcpi.vcpi > 0) {
2928			drm_dp_mst_reset_vcpi_slots(mgr, port);
2929			drm_dp_update_payload_part1(mgr);
2930			drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
2931		}
2932
2933		kref_put(&port->kref, drm_dp_free_mst_port);
2934		send_hotplug = true;
2935	}
2936	if (send_hotplug)
2937		(*mgr->cbs->hotplug)(mgr);
2938}
2939
2940/**
2941 * drm_dp_mst_topology_mgr_init - initialise a topology manager
2942 * @mgr: manager struct to initialise
2943 * @dev: device providing this structure - for i2c addition.
2944 * @aux: DP helper aux channel to talk to this device
2945 * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
2946 * @max_payloads: maximum number of payloads this GPU can source
2947 * @conn_base_id: the connector object ID the MST device is connected to.
2948 *
2949 * Return 0 for success, or negative error code on failure
2950 */
2951int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
2952				 struct device *dev, struct drm_dp_aux *aux,
2953				 int max_dpcd_transaction_bytes,
2954				 int max_payloads, int conn_base_id)
2955{
2956	mutex_init(&mgr->lock);
2957	mutex_init(&mgr->qlock);
2958	mutex_init(&mgr->payload_lock);
2959	mutex_init(&mgr->destroy_connector_lock);
2960	INIT_LIST_HEAD(&mgr->tx_msg_downq);
2961	INIT_LIST_HEAD(&mgr->destroy_connector_list);
2962	INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
2963	INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
2964	INIT_WORK(&mgr->destroy_connector_work, drm_dp_destroy_connector_work);
2965	init_waitqueue_head(&mgr->tx_waitq);
2966	mgr->dev = dev;
2967	mgr->aux = aux;
2968	mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
2969	mgr->max_payloads = max_payloads;
2970	mgr->conn_base_id = conn_base_id;
2971	if (max_payloads + 1 > sizeof(mgr->payload_mask) * 8 ||
2972	    max_payloads + 1 > sizeof(mgr->vcpi_mask) * 8)
2973		return -EINVAL;
2974	mgr->payloads = kcalloc(max_payloads, sizeof(struct drm_dp_payload), GFP_KERNEL);
2975	if (!mgr->payloads)
2976		return -ENOMEM;
2977	mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);
2978	if (!mgr->proposed_vcpis)
2979		return -ENOMEM;
2980	set_bit(0, &mgr->payload_mask);
2981	if (test_calc_pbn_mode() < 0)
2982		DRM_ERROR("MST PBN self-test failed\n");
2983
2984	return 0;
2985}
2986EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
2987
2988/**
2989 * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
2990 * @mgr: manager to destroy
2991 */
2992void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
2993{
2994	flush_work(&mgr->work);
2995	flush_work(&mgr->destroy_connector_work);
2996	mutex_lock(&mgr->payload_lock);
2997	kfree(mgr->payloads);
2998	mgr->payloads = NULL;
2999	kfree(mgr->proposed_vcpis);
3000	mgr->proposed_vcpis = NULL;
3001	mutex_unlock(&mgr->payload_lock);
3002	mgr->dev = NULL;
3003	mgr->aux = NULL;
3004}
3005EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
3006
3007/* I2C device */
3008static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
3009			       int num)
3010{
3011	struct drm_dp_aux *aux = adapter->algo_data;
3012	struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port, aux);
3013	struct drm_dp_mst_branch *mstb;
3014	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
3015	unsigned int i;
3016	bool reading = false;
3017	struct drm_dp_sideband_msg_req_body msg;
3018	struct drm_dp_sideband_msg_tx *txmsg = NULL;
3019	int ret;
3020
3021	mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
3022	if (!mstb)
3023		return -EREMOTEIO;
3024
3025	/* construct i2c msg */
3026	/* see if last msg is a read */
3027	if (msgs[num - 1].flags & I2C_M_RD)
3028		reading = true;
3029
3030	if (!reading || (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)) {
3031		DRM_DEBUG_KMS("Unsupported I2C transaction for MST device\n");
3032		ret = -EIO;
3033		goto out;
3034	}
3035
3036	memset(&msg, 0, sizeof(msg));
3037	msg.req_type = DP_REMOTE_I2C_READ;
3038	msg.u.i2c_read.num_transactions = num - 1;
3039	msg.u.i2c_read.port_number = port->port_num;
3040	for (i = 0; i < num - 1; i++) {
3041		msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
3042		msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
3043		msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
3044	}
3045	msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
3046	msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
3047
3048	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3049	if (!txmsg) {
3050		ret = -ENOMEM;
3051		goto out;
3052	}
3053
3054	txmsg->dst = mstb;
3055	drm_dp_encode_sideband_req(&msg, txmsg);
3056
3057	drm_dp_queue_down_tx(mgr, txmsg);
3058
3059	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3060	if (ret > 0) {
3061
3062		if (txmsg->reply.reply_type == 1) { /* got a NAK back */
3063			ret = -EREMOTEIO;
3064			goto out;
3065		}
3066		if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
3067			ret = -EIO;
3068			goto out;
3069		}
3070		memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
3071		ret = num;
3072	}
3073out:
3074	kfree(txmsg);
3075	drm_dp_put_mst_branch_device(mstb);
3076	return ret;
3077}
3078
3079static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
3080{
3081	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
3082	       I2C_FUNC_SMBUS_READ_BLOCK_DATA |
3083	       I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
3084	       I2C_FUNC_10BIT_ADDR;
3085}
3086
3087static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
3088	.functionality = drm_dp_mst_i2c_functionality,
3089	.master_xfer = drm_dp_mst_i2c_xfer,
3090};
3091
3092/**
3093 * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
3094 * @aux: DisplayPort AUX channel
3095 *
3096 * Returns 0 on success or a negative error code on failure.
3097 */
3098static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux)
3099{
3100	aux->ddc.algo = &drm_dp_mst_i2c_algo;
3101	aux->ddc.algo_data = aux;
3102	aux->ddc.retries = 3;
3103
3104	aux->ddc.class = I2C_CLASS_DDC;
3105	aux->ddc.owner = THIS_MODULE;
3106	aux->ddc.dev.parent = aux->dev;
3107	aux->ddc.dev.of_node = aux->dev->of_node;
3108
3109	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
3110		sizeof(aux->ddc.name));
3111
3112	return i2c_add_adapter(&aux->ddc);
3113}
3114
3115/**
3116 * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
3117 * @aux: DisplayPort AUX channel
3118 */
3119static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_aux *aux)
3120{
3121	i2c_del_adapter(&aux->ddc);
3122}