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	}
 918	kfree(port);
 919}
 920
 921static void drm_dp_put_port(struct drm_dp_mst_port *port)
 922{
 923	kref_put(&port->kref, drm_dp_destroy_port);
 924}
 925
 926static 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)
 927{
 928	struct drm_dp_mst_port *port;
 929	struct drm_dp_mst_branch *rmstb;
 930	if (to_find == mstb) {
 931		kref_get(&mstb->kref);
 932		return mstb;
 933	}
 934	list_for_each_entry(port, &mstb->ports, next) {
 935		if (port->mstb) {
 936			rmstb = drm_dp_mst_get_validated_mstb_ref_locked(port->mstb, to_find);
 937			if (rmstb)
 938				return rmstb;
 939		}
 940	}
 941	return NULL;
 942}
 943
 944static struct drm_dp_mst_branch *drm_dp_get_validated_mstb_ref(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_branch *mstb)
 945{
 946	struct drm_dp_mst_branch *rmstb = NULL;
 947	mutex_lock(&mgr->lock);
 948	if (mgr->mst_primary)
 949		rmstb = drm_dp_mst_get_validated_mstb_ref_locked(mgr->mst_primary, mstb);
 950	mutex_unlock(&mgr->lock);
 951	return rmstb;
 952}
 953
 954static 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)
 955{
 956	struct drm_dp_mst_port *port, *mport;
 957
 958	list_for_each_entry(port, &mstb->ports, next) {
 959		if (port == to_find) {
 960			kref_get(&port->kref);
 961			return port;
 962		}
 963		if (port->mstb) {
 964			mport = drm_dp_mst_get_port_ref_locked(port->mstb, to_find);
 965			if (mport)
 966				return mport;
 967		}
 968	}
 969	return NULL;
 970}
 971
 972static struct drm_dp_mst_port *drm_dp_get_validated_port_ref(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
 973{
 974	struct drm_dp_mst_port *rport = NULL;
 975	mutex_lock(&mgr->lock);
 976	if (mgr->mst_primary)
 977		rport = drm_dp_mst_get_port_ref_locked(mgr->mst_primary, port);
 978	mutex_unlock(&mgr->lock);
 979	return rport;
 980}
 981
 982static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u8 port_num)
 983{
 984	struct drm_dp_mst_port *port;
 985
 986	list_for_each_entry(port, &mstb->ports, next) {
 987		if (port->port_num == port_num) {
 988			kref_get(&port->kref);
 989			return port;
 990		}
 991	}
 992
 993	return NULL;
 994}
 995
 996/*
 997 * calculate a new RAD for this MST branch device
 998 * if parent has an LCT of 2 then it has 1 nibble of RAD,
 999 * if parent has an LCT of 3 then it has 2 nibbles of RAD,
1000 */
1001static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
1002				 u8 *rad)
1003{
1004	int parent_lct = port->parent->lct;
1005	int shift = 4;
1006	int idx = (parent_lct - 1) / 2;
1007	if (parent_lct > 1) {
1008		memcpy(rad, port->parent->rad, idx + 1);
1009		shift = (parent_lct % 2) ? 4 : 0;
1010	} else
1011		rad[0] = 0;
1012
1013	rad[idx] |= port->port_num << shift;
1014	return parent_lct + 1;
1015}
1016
1017/*
1018 * return sends link address for new mstb
1019 */
1020static bool drm_dp_port_setup_pdt(struct drm_dp_mst_port *port)
1021{
1022	int ret;
1023	u8 rad[6], lct;
1024	bool send_link = false;
1025	switch (port->pdt) {
1026	case DP_PEER_DEVICE_DP_LEGACY_CONV:
1027	case DP_PEER_DEVICE_SST_SINK:
1028		/* add i2c over sideband */
1029		ret = drm_dp_mst_register_i2c_bus(&port->aux);
1030		break;
1031	case DP_PEER_DEVICE_MST_BRANCHING:
1032		lct = drm_dp_calculate_rad(port, rad);
1033
1034		port->mstb = drm_dp_add_mst_branch_device(lct, rad);
1035		port->mstb->mgr = port->mgr;
1036		port->mstb->port_parent = port;
1037
1038		send_link = true;
1039		break;
1040	}
1041	return send_link;
1042}
1043
1044static void drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, u8 *guid)
1045{
1046	int ret;
1047
1048	memcpy(mstb->guid, guid, 16);
1049
1050	if (!drm_dp_validate_guid(mstb->mgr, mstb->guid)) {
1051		if (mstb->port_parent) {
1052			ret = drm_dp_send_dpcd_write(
1053					mstb->mgr,
1054					mstb->port_parent,
1055					DP_GUID,
1056					16,
1057					mstb->guid);
1058		} else {
1059
1060			ret = drm_dp_dpcd_write(
1061					mstb->mgr->aux,
1062					DP_GUID,
1063					mstb->guid,
1064					16);
1065		}
1066	}
1067}
1068
1069static void build_mst_prop_path(const struct drm_dp_mst_branch *mstb,
1070				int pnum,
1071				char *proppath,
1072				size_t proppath_size)
1073{
1074	int i;
1075	char temp[8];
1076	snprintf(proppath, proppath_size, "mst:%d", mstb->mgr->conn_base_id);
1077	for (i = 0; i < (mstb->lct - 1); i++) {
1078		int shift = (i % 2) ? 0 : 4;
1079		int port_num = (mstb->rad[i / 2] >> shift) & 0xf;
1080		snprintf(temp, sizeof(temp), "-%d", port_num);
1081		strlcat(proppath, temp, proppath_size);
1082	}
1083	snprintf(temp, sizeof(temp), "-%d", pnum);
1084	strlcat(proppath, temp, proppath_size);
1085}
1086
1087static void drm_dp_add_port(struct drm_dp_mst_branch *mstb,
1088			    struct device *dev,
1089			    struct drm_dp_link_addr_reply_port *port_msg)
1090{
1091	struct drm_dp_mst_port *port;
1092	bool ret;
1093	bool created = false;
1094	int old_pdt = 0;
1095	int old_ddps = 0;
1096	port = drm_dp_get_port(mstb, port_msg->port_number);
1097	if (!port) {
1098		port = kzalloc(sizeof(*port), GFP_KERNEL);
1099		if (!port)
1100			return;
1101		kref_init(&port->kref);
1102		port->parent = mstb;
1103		port->port_num = port_msg->port_number;
1104		port->mgr = mstb->mgr;
1105		port->aux.name = "DPMST";
1106		port->aux.dev = dev;
1107		created = true;
1108	} else {
1109		old_pdt = port->pdt;
1110		old_ddps = port->ddps;
1111	}
1112
1113	port->pdt = port_msg->peer_device_type;
1114	port->input = port_msg->input_port;
1115	port->mcs = port_msg->mcs;
1116	port->ddps = port_msg->ddps;
1117	port->ldps = port_msg->legacy_device_plug_status;
1118	port->dpcd_rev = port_msg->dpcd_revision;
1119	port->num_sdp_streams = port_msg->num_sdp_streams;
1120	port->num_sdp_stream_sinks = port_msg->num_sdp_stream_sinks;
1121
1122	/* manage mstb port lists with mgr lock - take a reference
1123	   for this list */
1124	if (created) {
1125		mutex_lock(&mstb->mgr->lock);
1126		kref_get(&port->kref);
1127		list_add(&port->next, &mstb->ports);
1128		mutex_unlock(&mstb->mgr->lock);
1129	}
1130
1131	if (old_ddps != port->ddps) {
1132		if (port->ddps) {
1133			if (!port->input)
1134				drm_dp_send_enum_path_resources(mstb->mgr, mstb, port);
1135		} else {
1136			port->available_pbn = 0;
1137			}
1138	}
1139
1140	if (old_pdt != port->pdt && !port->input) {
1141		drm_dp_port_teardown_pdt(port, old_pdt);
1142
1143		ret = drm_dp_port_setup_pdt(port);
1144		if (ret == true)
1145			drm_dp_send_link_address(mstb->mgr, port->mstb);
1146	}
1147
1148	if (created && !port->input) {
1149		char proppath[255];
1150
1151		build_mst_prop_path(mstb, port->port_num, proppath, sizeof(proppath));
1152		port->connector = (*mstb->mgr->cbs->add_connector)(mstb->mgr, port, proppath);
1153		if (!port->connector) {
1154			/* remove it from the port list */
1155			mutex_lock(&mstb->mgr->lock);
1156			list_del(&port->next);
1157			mutex_unlock(&mstb->mgr->lock);
1158			/* drop port list reference */
1159			drm_dp_put_port(port);
1160			goto out;
1161		}
1162		if (port->port_num >= DP_MST_LOGICAL_PORT_0) {
1163			port->cached_edid = drm_get_edid(port->connector, &port->aux.ddc);
1164			drm_mode_connector_set_tile_property(port->connector);
1165		}
1166		(*mstb->mgr->cbs->register_connector)(port->connector);
1167	}
1168
1169out:
1170	/* put reference to this port */
1171	drm_dp_put_port(port);
1172}
1173
1174static void drm_dp_update_port(struct drm_dp_mst_branch *mstb,
1175			       struct drm_dp_connection_status_notify *conn_stat)
1176{
1177	struct drm_dp_mst_port *port;
1178	int old_pdt;
1179	int old_ddps;
1180	bool dowork = false;
1181	port = drm_dp_get_port(mstb, conn_stat->port_number);
1182	if (!port)
1183		return;
1184
1185	old_ddps = port->ddps;
1186	old_pdt = port->pdt;
1187	port->pdt = conn_stat->peer_device_type;
1188	port->mcs = conn_stat->message_capability_status;
1189	port->ldps = conn_stat->legacy_device_plug_status;
1190	port->ddps = conn_stat->displayport_device_plug_status;
1191
1192	if (old_ddps != port->ddps) {
1193		if (port->ddps) {
1194			dowork = true;
1195		} else {
1196			port->available_pbn = 0;
1197		}
1198	}
1199	if (old_pdt != port->pdt && !port->input) {
1200		drm_dp_port_teardown_pdt(port, old_pdt);
1201
1202		if (drm_dp_port_setup_pdt(port))
1203			dowork = true;
1204	}
1205
1206	drm_dp_put_port(port);
1207	if (dowork)
1208		queue_work(system_long_wq, &mstb->mgr->work);
1209
1210}
1211
1212static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_topology_mgr *mgr,
1213							       u8 lct, u8 *rad)
1214{
1215	struct drm_dp_mst_branch *mstb;
1216	struct drm_dp_mst_port *port;
1217	int i;
1218	/* find the port by iterating down */
1219
1220	mutex_lock(&mgr->lock);
1221	mstb = mgr->mst_primary;
1222
1223	for (i = 0; i < lct - 1; i++) {
1224		int shift = (i % 2) ? 0 : 4;
1225		int port_num = (rad[i / 2] >> shift) & 0xf;
1226
1227		list_for_each_entry(port, &mstb->ports, next) {
1228			if (port->port_num == port_num) {
1229				mstb = port->mstb;
1230				if (!mstb) {
1231					DRM_ERROR("failed to lookup MSTB with lct %d, rad %02x\n", lct, rad[0]);
1232					goto out;
1233				}
1234
1235				break;
1236			}
1237		}
1238	}
1239	kref_get(&mstb->kref);
1240out:
1241	mutex_unlock(&mgr->lock);
1242	return mstb;
1243}
1244
1245static struct drm_dp_mst_branch *get_mst_branch_device_by_guid_helper(
1246	struct drm_dp_mst_branch *mstb,
1247	uint8_t *guid)
1248{
1249	struct drm_dp_mst_branch *found_mstb;
1250	struct drm_dp_mst_port *port;
1251
1252	if (memcmp(mstb->guid, guid, 16) == 0)
1253		return mstb;
1254
1255
1256	list_for_each_entry(port, &mstb->ports, next) {
1257		if (!port->mstb)
1258			continue;
1259
1260		found_mstb = get_mst_branch_device_by_guid_helper(port->mstb, guid);
1261
1262		if (found_mstb)
1263			return found_mstb;
1264	}
1265
1266	return NULL;
1267}
1268
1269static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device_by_guid(
1270	struct drm_dp_mst_topology_mgr *mgr,
1271	uint8_t *guid)
1272{
1273	struct drm_dp_mst_branch *mstb;
1274
1275	/* find the port by iterating down */
1276	mutex_lock(&mgr->lock);
1277
1278	mstb = get_mst_branch_device_by_guid_helper(mgr->mst_primary, guid);
1279
1280	if (mstb)
1281		kref_get(&mstb->kref);
1282
1283	mutex_unlock(&mgr->lock);
1284	return mstb;
1285}
1286
1287static void drm_dp_check_and_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
1288					       struct drm_dp_mst_branch *mstb)
1289{
1290	struct drm_dp_mst_port *port;
1291	struct drm_dp_mst_branch *mstb_child;
1292	if (!mstb->link_address_sent)
1293		drm_dp_send_link_address(mgr, mstb);
1294
1295	list_for_each_entry(port, &mstb->ports, next) {
1296		if (port->input)
1297			continue;
1298
1299		if (!port->ddps)
1300			continue;
1301
1302		if (!port->available_pbn)
1303			drm_dp_send_enum_path_resources(mgr, mstb, port);
1304
1305		if (port->mstb) {
1306			mstb_child = drm_dp_get_validated_mstb_ref(mgr, port->mstb);
1307			if (mstb_child) {
1308				drm_dp_check_and_send_link_address(mgr, mstb_child);
1309				drm_dp_put_mst_branch_device(mstb_child);
1310			}
1311		}
1312	}
1313}
1314
1315static void drm_dp_mst_link_probe_work(struct work_struct *work)
1316{
1317	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, work);
1318	struct drm_dp_mst_branch *mstb;
1319
1320	mutex_lock(&mgr->lock);
1321	mstb = mgr->mst_primary;
1322	if (mstb) {
1323		kref_get(&mstb->kref);
1324	}
1325	mutex_unlock(&mgr->lock);
1326	if (mstb) {
1327		drm_dp_check_and_send_link_address(mgr, mstb);
1328		drm_dp_put_mst_branch_device(mstb);
1329	}
1330}
1331
1332static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
1333				 u8 *guid)
1334{
1335	static u8 zero_guid[16];
1336
1337	if (!memcmp(guid, zero_guid, 16)) {
1338		u64 salt = get_jiffies_64();
1339		memcpy(&guid[0], &salt, sizeof(u64));
1340		memcpy(&guid[8], &salt, sizeof(u64));
1341		return false;
1342	}
1343	return true;
1344}
1345
1346#if 0
1347static int build_dpcd_read(struct drm_dp_sideband_msg_tx *msg, u8 port_num, u32 offset, u8 num_bytes)
1348{
1349	struct drm_dp_sideband_msg_req_body req;
1350
1351	req.req_type = DP_REMOTE_DPCD_READ;
1352	req.u.dpcd_read.port_number = port_num;
1353	req.u.dpcd_read.dpcd_address = offset;
1354	req.u.dpcd_read.num_bytes = num_bytes;
1355	drm_dp_encode_sideband_req(&req, msg);
1356
1357	return 0;
1358}
1359#endif
1360
1361static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
1362				    bool up, u8 *msg, int len)
1363{
1364	int ret;
1365	int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : DP_SIDEBAND_MSG_DOWN_REQ_BASE;
1366	int tosend, total, offset;
1367	int retries = 0;
1368
1369retry:
1370	total = len;
1371	offset = 0;
1372	do {
1373		tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
1374
1375		ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
1376					&msg[offset],
1377					tosend);
1378		if (ret != tosend) {
1379			if (ret == -EIO && retries < 5) {
1380				retries++;
1381				goto retry;
1382			}
1383			DRM_DEBUG_KMS("failed to dpcd write %d %d\n", tosend, ret);
1384
1385			return -EIO;
1386		}
1387		offset += tosend;
1388		total -= tosend;
1389	} while (total > 0);
1390	return 0;
1391}
1392
1393static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
1394				  struct drm_dp_sideband_msg_tx *txmsg)
1395{
1396	struct drm_dp_mst_branch *mstb = txmsg->dst;
1397	u8 req_type;
1398
1399	/* both msg slots are full */
1400	if (txmsg->seqno == -1) {
1401		if (mstb->tx_slots[0] && mstb->tx_slots[1]) {
1402			DRM_DEBUG_KMS("%s: failed to find slot\n", __func__);
1403			return -EAGAIN;
1404		}
1405		if (mstb->tx_slots[0] == NULL && mstb->tx_slots[1] == NULL) {
1406			txmsg->seqno = mstb->last_seqno;
1407			mstb->last_seqno ^= 1;
1408		} else if (mstb->tx_slots[0] == NULL)
1409			txmsg->seqno = 0;
1410		else
1411			txmsg->seqno = 1;
1412		mstb->tx_slots[txmsg->seqno] = txmsg;
1413	}
1414
1415	req_type = txmsg->msg[0] & 0x7f;
1416	if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
1417		req_type == DP_RESOURCE_STATUS_NOTIFY)
1418		hdr->broadcast = 1;
1419	else
1420		hdr->broadcast = 0;
1421	hdr->path_msg = txmsg->path_msg;
1422	hdr->lct = mstb->lct;
1423	hdr->lcr = mstb->lct - 1;
1424	if (mstb->lct > 1)
1425		memcpy(hdr->rad, mstb->rad, mstb->lct / 2);
1426	hdr->seqno = txmsg->seqno;
1427	return 0;
1428}
1429/*
1430 * process a single block of the next message in the sideband queue
1431 */
1432static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
1433				   struct drm_dp_sideband_msg_tx *txmsg,
1434				   bool up)
1435{
1436	u8 chunk[48];
1437	struct drm_dp_sideband_msg_hdr hdr;
1438	int len, space, idx, tosend;
1439	int ret;
1440
1441	memset(&hdr, 0, sizeof(struct drm_dp_sideband_msg_hdr));
1442
1443	if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED) {
1444		txmsg->seqno = -1;
1445		txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
1446	}
1447
1448	/* make hdr from dst mst - for replies use seqno
1449	   otherwise assign one */
1450	ret = set_hdr_from_dst_qlock(&hdr, txmsg);
1451	if (ret < 0)
1452		return ret;
1453
1454	/* amount left to send in this message */
1455	len = txmsg->cur_len - txmsg->cur_offset;
1456
1457	/* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
1458	space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
1459
1460	tosend = min(len, space);
1461	if (len == txmsg->cur_len)
1462		hdr.somt = 1;
1463	if (space >= len)
1464		hdr.eomt = 1;
1465
1466
1467	hdr.msg_len = tosend + 1;
1468	drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
1469	memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
1470	/* add crc at end */
1471	drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
1472	idx += tosend + 1;
1473
1474	ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
1475	if (ret) {
1476		DRM_DEBUG_KMS("sideband msg failed to send\n");
1477		return ret;
1478	}
1479
1480	txmsg->cur_offset += tosend;
1481	if (txmsg->cur_offset == txmsg->cur_len) {
1482		txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
1483		return 1;
1484	}
1485	return 0;
1486}
1487
1488static void process_single_down_tx_qlock(struct drm_dp_mst_topology_mgr *mgr)
1489{
1490	struct drm_dp_sideband_msg_tx *txmsg;
1491	int ret;
1492
1493	WARN_ON(!mutex_is_locked(&mgr->qlock));
1494
1495	/* construct a chunk from the first msg in the tx_msg queue */
1496	if (list_empty(&mgr->tx_msg_downq)) {
1497		mgr->tx_down_in_progress = false;
1498		return;
1499	}
1500	mgr->tx_down_in_progress = true;
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	if (list_empty(&mgr->tx_msg_downq)) {
1516		mgr->tx_down_in_progress = false;
1517		return;
1518	}
1519}
1520
1521/* called holding qlock */
1522static void process_single_up_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
1523				       struct drm_dp_sideband_msg_tx *txmsg)
1524{
1525	int ret;
1526
1527	/* construct a chunk from the first msg in the tx_msg queue */
1528	ret = process_single_tx_qlock(mgr, txmsg, true);
1529
1530	if (ret != 1)
1531		DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
1532
1533	txmsg->dst->tx_slots[txmsg->seqno] = NULL;
1534}
1535
1536static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
1537				 struct drm_dp_sideband_msg_tx *txmsg)
1538{
1539	mutex_lock(&mgr->qlock);
1540	list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
1541	if (!mgr->tx_down_in_progress)
1542		process_single_down_tx_qlock(mgr);
1543	mutex_unlock(&mgr->qlock);
1544}
1545
1546static void drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
1547				     struct drm_dp_mst_branch *mstb)
1548{
1549	int len;
1550	struct drm_dp_sideband_msg_tx *txmsg;
1551	int ret;
1552
1553	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1554	if (!txmsg)
1555		return;
1556
1557	txmsg->dst = mstb;
1558	len = build_link_address(txmsg);
1559
1560	mstb->link_address_sent = true;
1561	drm_dp_queue_down_tx(mgr, txmsg);
1562
1563	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1564	if (ret > 0) {
1565		int i;
1566
1567		if (txmsg->reply.reply_type == 1)
1568			DRM_DEBUG_KMS("link address nak received\n");
1569		else {
1570			DRM_DEBUG_KMS("link address reply: %d\n", txmsg->reply.u.link_addr.nports);
1571			for (i = 0; i < txmsg->reply.u.link_addr.nports; i++) {
1572				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,
1573				       txmsg->reply.u.link_addr.ports[i].input_port,
1574				       txmsg->reply.u.link_addr.ports[i].peer_device_type,
1575				       txmsg->reply.u.link_addr.ports[i].port_number,
1576				       txmsg->reply.u.link_addr.ports[i].dpcd_revision,
1577				       txmsg->reply.u.link_addr.ports[i].mcs,
1578				       txmsg->reply.u.link_addr.ports[i].ddps,
1579				       txmsg->reply.u.link_addr.ports[i].legacy_device_plug_status,
1580				       txmsg->reply.u.link_addr.ports[i].num_sdp_streams,
1581				       txmsg->reply.u.link_addr.ports[i].num_sdp_stream_sinks);
1582			}
1583
1584			drm_dp_check_mstb_guid(mstb, txmsg->reply.u.link_addr.guid);
1585
1586			for (i = 0; i < txmsg->reply.u.link_addr.nports; i++) {
1587				drm_dp_add_port(mstb, mgr->dev, &txmsg->reply.u.link_addr.ports[i]);
1588			}
1589			(*mgr->cbs->hotplug)(mgr);
1590		}
1591	} else {
1592		mstb->link_address_sent = false;
1593		DRM_DEBUG_KMS("link address failed %d\n", ret);
1594	}
1595
1596	kfree(txmsg);
1597}
1598
1599static int drm_dp_send_enum_path_resources(struct drm_dp_mst_topology_mgr *mgr,
1600					   struct drm_dp_mst_branch *mstb,
1601					   struct drm_dp_mst_port *port)
1602{
1603	int len;
1604	struct drm_dp_sideband_msg_tx *txmsg;
1605	int ret;
1606
1607	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1608	if (!txmsg)
1609		return -ENOMEM;
1610
1611	txmsg->dst = mstb;
1612	len = build_enum_path_resources(txmsg, port->port_num);
1613
1614	drm_dp_queue_down_tx(mgr, txmsg);
1615
1616	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1617	if (ret > 0) {
1618		if (txmsg->reply.reply_type == 1)
1619			DRM_DEBUG_KMS("enum path resources nak received\n");
1620		else {
1621			if (port->port_num != txmsg->reply.u.path_resources.port_number)
1622				DRM_ERROR("got incorrect port in response\n");
1623			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,
1624			       txmsg->reply.u.path_resources.avail_payload_bw_number);
1625			port->available_pbn = txmsg->reply.u.path_resources.avail_payload_bw_number;
1626		}
1627	}
1628
1629	kfree(txmsg);
1630	return 0;
1631}
1632
1633static struct drm_dp_mst_port *drm_dp_get_last_connected_port_to_mstb(struct drm_dp_mst_branch *mstb)
1634{
1635	if (!mstb->port_parent)
1636		return NULL;
1637
1638	if (mstb->port_parent->mstb != mstb)
1639		return mstb->port_parent;
1640
1641	return drm_dp_get_last_connected_port_to_mstb(mstb->port_parent->parent);
1642}
1643
1644static struct drm_dp_mst_branch *drm_dp_get_last_connected_port_and_mstb(struct drm_dp_mst_topology_mgr *mgr,
1645									 struct drm_dp_mst_branch *mstb,
1646									 int *port_num)
1647{
1648	struct drm_dp_mst_branch *rmstb = NULL;
1649	struct drm_dp_mst_port *found_port;
1650	mutex_lock(&mgr->lock);
1651	if (mgr->mst_primary) {
1652		found_port = drm_dp_get_last_connected_port_to_mstb(mstb);
1653
1654		if (found_port) {
1655			rmstb = found_port->parent;
1656			kref_get(&rmstb->kref);
1657			*port_num = found_port->port_num;
1658		}
1659	}
1660	mutex_unlock(&mgr->lock);
1661	return rmstb;
1662}
1663
1664static int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
1665				   struct drm_dp_mst_port *port,
1666				   int id,
1667				   int pbn)
1668{
1669	struct drm_dp_sideband_msg_tx *txmsg;
1670	struct drm_dp_mst_branch *mstb;
1671	int len, ret, port_num;
1672	u8 sinks[DRM_DP_MAX_SDP_STREAMS];
1673	int i;
1674
1675	port = drm_dp_get_validated_port_ref(mgr, port);
1676	if (!port)
1677		return -EINVAL;
1678
1679	port_num = port->port_num;
1680	mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
1681	if (!mstb) {
1682		mstb = drm_dp_get_last_connected_port_and_mstb(mgr, port->parent, &port_num);
1683
1684		if (!mstb) {
1685			drm_dp_put_port(port);
1686			return -EINVAL;
1687		}
1688	}
1689
1690	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1691	if (!txmsg) {
1692		ret = -ENOMEM;
1693		goto fail_put;
1694	}
1695
1696	for (i = 0; i < port->num_sdp_streams; i++)
1697		sinks[i] = i;
1698
1699	txmsg->dst = mstb;
1700	len = build_allocate_payload(txmsg, port_num,
1701				     id,
1702				     pbn, port->num_sdp_streams, sinks);
1703
1704	drm_dp_queue_down_tx(mgr, txmsg);
1705
1706	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1707	if (ret > 0) {
1708		if (txmsg->reply.reply_type == 1) {
1709			ret = -EINVAL;
1710		} else
1711			ret = 0;
1712	}
1713	kfree(txmsg);
1714fail_put:
1715	drm_dp_put_mst_branch_device(mstb);
1716	drm_dp_put_port(port);
1717	return ret;
1718}
1719
1720static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
1721				       int id,
1722				       struct drm_dp_payload *payload)
1723{
1724	int ret;
1725
1726	ret = drm_dp_dpcd_write_payload(mgr, id, payload);
1727	if (ret < 0) {
1728		payload->payload_state = 0;
1729		return ret;
1730	}
1731	payload->payload_state = DP_PAYLOAD_LOCAL;
1732	return 0;
1733}
1734
1735static int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
1736				       struct drm_dp_mst_port *port,
1737				       int id,
1738				       struct drm_dp_payload *payload)
1739{
1740	int ret;
1741	ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
1742	if (ret < 0)
1743		return ret;
1744	payload->payload_state = DP_PAYLOAD_REMOTE;
1745	return ret;
1746}
1747
1748static int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
1749					struct drm_dp_mst_port *port,
1750					int id,
1751					struct drm_dp_payload *payload)
1752{
1753	DRM_DEBUG_KMS("\n");
1754	/* its okay for these to fail */
1755	if (port) {
1756		drm_dp_payload_send_msg(mgr, port, id, 0);
1757	}
1758
1759	drm_dp_dpcd_write_payload(mgr, id, payload);
1760	payload->payload_state = DP_PAYLOAD_DELETE_LOCAL;
1761	return 0;
1762}
1763
1764static int drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
1765					int id,
1766					struct drm_dp_payload *payload)
1767{
1768	payload->payload_state = 0;
1769	return 0;
1770}
1771
1772/**
1773 * drm_dp_update_payload_part1() - Execute payload update part 1
1774 * @mgr: manager to use.
1775 *
1776 * This iterates over all proposed virtual channels, and tries to
1777 * allocate space in the link for them. For 0->slots transitions,
1778 * this step just writes the VCPI to the MST device. For slots->0
1779 * transitions, this writes the updated VCPIs and removes the
1780 * remote VC payloads.
1781 *
1782 * after calling this the driver should generate ACT and payload
1783 * packets.
1784 */
1785int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
1786{
1787	int i, j;
1788	int cur_slots = 1;
1789	struct drm_dp_payload req_payload;
1790	struct drm_dp_mst_port *port;
1791
1792	mutex_lock(&mgr->payload_lock);
1793	for (i = 0; i < mgr->max_payloads; i++) {
1794		/* solve the current payloads - compare to the hw ones
1795		   - update the hw view */
1796		req_payload.start_slot = cur_slots;
1797		if (mgr->proposed_vcpis[i]) {
1798			port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
1799			port = drm_dp_get_validated_port_ref(mgr, port);
1800			if (!port) {
1801				mutex_unlock(&mgr->payload_lock);
1802				return -EINVAL;
1803			}
1804			req_payload.num_slots = mgr->proposed_vcpis[i]->num_slots;
1805			req_payload.vcpi = mgr->proposed_vcpis[i]->vcpi;
1806		} else {
1807			port = NULL;
1808			req_payload.num_slots = 0;
1809		}
1810
1811		if (mgr->payloads[i].start_slot != req_payload.start_slot) {
1812			mgr->payloads[i].start_slot = req_payload.start_slot;
1813		}
1814		/* work out what is required to happen with this payload */
1815		if (mgr->payloads[i].num_slots != req_payload.num_slots) {
1816
1817			/* need to push an update for this payload */
1818			if (req_payload.num_slots) {
1819				drm_dp_create_payload_step1(mgr, mgr->proposed_vcpis[i]->vcpi, &req_payload);
1820				mgr->payloads[i].num_slots = req_payload.num_slots;
1821				mgr->payloads[i].vcpi = req_payload.vcpi;
1822			} else if (mgr->payloads[i].num_slots) {
1823				mgr->payloads[i].num_slots = 0;
1824				drm_dp_destroy_payload_step1(mgr, port, port->vcpi.vcpi, &mgr->payloads[i]);
1825				req_payload.payload_state = mgr->payloads[i].payload_state;
1826				mgr->payloads[i].start_slot = 0;
1827			}
1828			mgr->payloads[i].payload_state = req_payload.payload_state;
1829		}
1830		cur_slots += req_payload.num_slots;
1831
1832		if (port)
1833			drm_dp_put_port(port);
1834	}
1835
1836	for (i = 0; i < mgr->max_payloads; i++) {
1837		if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
1838			DRM_DEBUG_KMS("removing payload %d\n", i);
1839			for (j = i; j < mgr->max_payloads - 1; j++) {
1840				memcpy(&mgr->payloads[j], &mgr->payloads[j + 1], sizeof(struct drm_dp_payload));
1841				mgr->proposed_vcpis[j] = mgr->proposed_vcpis[j + 1];
1842				if (mgr->proposed_vcpis[j] && mgr->proposed_vcpis[j]->num_slots) {
1843					set_bit(j + 1, &mgr->payload_mask);
1844				} else {
1845					clear_bit(j + 1, &mgr->payload_mask);
1846				}
1847			}
1848			memset(&mgr->payloads[mgr->max_payloads - 1], 0, sizeof(struct drm_dp_payload));
1849			mgr->proposed_vcpis[mgr->max_payloads - 1] = NULL;
1850			clear_bit(mgr->max_payloads, &mgr->payload_mask);
1851
1852		}
1853	}
1854	mutex_unlock(&mgr->payload_lock);
1855
1856	return 0;
1857}
1858EXPORT_SYMBOL(drm_dp_update_payload_part1);
1859
1860/**
1861 * drm_dp_update_payload_part2() - Execute payload update part 2
1862 * @mgr: manager to use.
1863 *
1864 * This iterates over all proposed virtual channels, and tries to
1865 * allocate space in the link for them. For 0->slots transitions,
1866 * this step writes the remote VC payload commands. For slots->0
1867 * this just resets some internal state.
1868 */
1869int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
1870{
1871	struct drm_dp_mst_port *port;
1872	int i;
1873	int ret = 0;
1874	mutex_lock(&mgr->payload_lock);
1875	for (i = 0; i < mgr->max_payloads; i++) {
1876
1877		if (!mgr->proposed_vcpis[i])
1878			continue;
1879
1880		port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
1881
1882		DRM_DEBUG_KMS("payload %d %d\n", i, mgr->payloads[i].payload_state);
1883		if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
1884			ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
1885		} else if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
1886			ret = drm_dp_destroy_payload_step2(mgr, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
1887		}
1888		if (ret) {
1889			mutex_unlock(&mgr->payload_lock);
1890			return ret;
1891		}
1892	}
1893	mutex_unlock(&mgr->payload_lock);
1894	return 0;
1895}
1896EXPORT_SYMBOL(drm_dp_update_payload_part2);
1897
1898#if 0 /* unused as of yet */
1899static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
1900				 struct drm_dp_mst_port *port,
1901				 int offset, int size)
1902{
1903	int len;
1904	struct drm_dp_sideband_msg_tx *txmsg;
1905
1906	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1907	if (!txmsg)
1908		return -ENOMEM;
1909
1910	len = build_dpcd_read(txmsg, port->port_num, 0, 8);
1911	txmsg->dst = port->parent;
1912
1913	drm_dp_queue_down_tx(mgr, txmsg);
1914
1915	return 0;
1916}
1917#endif
1918
1919static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
1920				  struct drm_dp_mst_port *port,
1921				  int offset, int size, u8 *bytes)
1922{
1923	int len;
1924	int ret;
1925	struct drm_dp_sideband_msg_tx *txmsg;
1926	struct drm_dp_mst_branch *mstb;
1927
1928	mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
1929	if (!mstb)
1930		return -EINVAL;
1931
1932	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1933	if (!txmsg) {
1934		ret = -ENOMEM;
1935		goto fail_put;
1936	}
1937
1938	len = build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
1939	txmsg->dst = mstb;
1940
1941	drm_dp_queue_down_tx(mgr, txmsg);
1942
1943	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
1944	if (ret > 0) {
1945		if (txmsg->reply.reply_type == 1) {
1946			ret = -EINVAL;
1947		} else
1948			ret = 0;
1949	}
1950	kfree(txmsg);
1951fail_put:
1952	drm_dp_put_mst_branch_device(mstb);
1953	return ret;
1954}
1955
1956static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx *msg, u8 req_type)
1957{
1958	struct drm_dp_sideband_msg_reply_body reply;
1959
1960	reply.reply_type = 0;
1961	reply.req_type = req_type;
1962	drm_dp_encode_sideband_reply(&reply, msg);
1963	return 0;
1964}
1965
1966static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
1967				    struct drm_dp_mst_branch *mstb,
1968				    int req_type, int seqno, bool broadcast)
1969{
1970	struct drm_dp_sideband_msg_tx *txmsg;
1971
1972	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
1973	if (!txmsg)
1974		return -ENOMEM;
1975
1976	txmsg->dst = mstb;
1977	txmsg->seqno = seqno;
1978	drm_dp_encode_up_ack_reply(txmsg, req_type);
1979
1980	mutex_lock(&mgr->qlock);
1981
1982	process_single_up_tx_qlock(mgr, txmsg);
1983
1984	mutex_unlock(&mgr->qlock);
1985
1986	kfree(txmsg);
1987	return 0;
1988}
1989
1990static bool drm_dp_get_vc_payload_bw(int dp_link_bw,
1991				     int dp_link_count,
1992				     int *out)
1993{
1994	switch (dp_link_bw) {
1995	default:
1996		DRM_DEBUG_KMS("invalid link bandwidth in DPCD: %x (link count: %d)\n",
1997			      dp_link_bw, dp_link_count);
1998		return false;
1999
2000	case DP_LINK_BW_1_62:
2001		*out = 3 * dp_link_count;
2002		break;
2003	case DP_LINK_BW_2_7:
2004		*out = 5 * dp_link_count;
2005		break;
2006	case DP_LINK_BW_5_4:
2007		*out = 10 * dp_link_count;
2008		break;
2009	}
2010	return true;
2011}
2012
2013/**
2014 * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a topology manager
2015 * @mgr: manager to set state for
2016 * @mst_state: true to enable MST on this connector - false to disable.
2017 *
2018 * This is called by the driver when it detects an MST capable device plugged
2019 * into a DP MST capable port, or when a DP MST capable device is unplugged.
2020 */
2021int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool mst_state)
2022{
2023	int ret = 0;
2024	struct drm_dp_mst_branch *mstb = NULL;
2025
2026	mutex_lock(&mgr->lock);
2027	if (mst_state == mgr->mst_state)
2028		goto out_unlock;
2029
2030	mgr->mst_state = mst_state;
2031	/* set the device into MST mode */
2032	if (mst_state) {
2033		WARN_ON(mgr->mst_primary);
2034
2035		/* get dpcd info */
2036		ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, DP_RECEIVER_CAP_SIZE);
2037		if (ret != DP_RECEIVER_CAP_SIZE) {
2038			DRM_DEBUG_KMS("failed to read DPCD\n");
2039			goto out_unlock;
2040		}
2041
2042		if (!drm_dp_get_vc_payload_bw(mgr->dpcd[1],
2043					      mgr->dpcd[2] & DP_MAX_LANE_COUNT_MASK,
2044					      &mgr->pbn_div)) {
2045			ret = -EINVAL;
2046			goto out_unlock;
2047		}
2048
2049		mgr->total_pbn = 2560;
2050		mgr->total_slots = DIV_ROUND_UP(mgr->total_pbn, mgr->pbn_div);
2051		mgr->avail_slots = mgr->total_slots;
2052
2053		/* add initial branch device at LCT 1 */
2054		mstb = drm_dp_add_mst_branch_device(1, NULL);
2055		if (mstb == NULL) {
2056			ret = -ENOMEM;
2057			goto out_unlock;
2058		}
2059		mstb->mgr = mgr;
2060
2061		/* give this the main reference */
2062		mgr->mst_primary = mstb;
2063		kref_get(&mgr->mst_primary->kref);
2064
2065		ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2066							 DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC);
2067		if (ret < 0) {
2068			goto out_unlock;
2069		}
2070
2071		{
2072			struct drm_dp_payload reset_pay;
2073			reset_pay.start_slot = 0;
2074			reset_pay.num_slots = 0x3f;
2075			drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
2076		}
2077
2078		queue_work(system_long_wq, &mgr->work);
2079
2080		ret = 0;
2081	} else {
2082		/* disable MST on the device */
2083		mstb = mgr->mst_primary;
2084		mgr->mst_primary = NULL;
2085		/* this can fail if the device is gone */
2086		drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
2087		ret = 0;
2088		memset(mgr->payloads, 0, mgr->max_payloads * sizeof(struct drm_dp_payload));
2089		mgr->payload_mask = 0;
2090		set_bit(0, &mgr->payload_mask);
2091		mgr->vcpi_mask = 0;
2092	}
2093
2094out_unlock:
2095	mutex_unlock(&mgr->lock);
2096	if (mstb)
2097		drm_dp_put_mst_branch_device(mstb);
2098	return ret;
2099
2100}
2101EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
2102
2103/**
2104 * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
2105 * @mgr: manager to suspend
2106 *
2107 * This function tells the MST device that we can't handle UP messages
2108 * anymore. This should stop it from sending any since we are suspended.
2109 */
2110void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
2111{
2112	mutex_lock(&mgr->lock);
2113	drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2114			   DP_MST_EN | DP_UPSTREAM_IS_SRC);
2115	mutex_unlock(&mgr->lock);
2116	flush_work(&mgr->work);
2117	flush_work(&mgr->destroy_connector_work);
2118}
2119EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
2120
2121/**
2122 * drm_dp_mst_topology_mgr_resume() - resume the MST manager
2123 * @mgr: manager to resume
2124 *
2125 * This will fetch DPCD and see if the device is still there,
2126 * if it is, it will rewrite the MSTM control bits, and return.
2127 *
2128 * if the device fails this returns -1, and the driver should do
2129 * a full MST reprobe, in case we were undocked.
2130 */
2131int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr)
2132{
2133	int ret = 0;
2134
2135	mutex_lock(&mgr->lock);
2136
2137	if (mgr->mst_primary) {
2138		int sret;
2139		u8 guid[16];
2140
2141		sret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, DP_RECEIVER_CAP_SIZE);
2142		if (sret != DP_RECEIVER_CAP_SIZE) {
2143			DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
2144			ret = -1;
2145			goto out_unlock;
2146		}
2147
2148		ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
2149					 DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC);
2150		if (ret < 0) {
2151			DRM_DEBUG_KMS("mst write failed - undocked during suspend?\n");
2152			ret = -1;
2153			goto out_unlock;
2154		}
2155
2156		/* Some hubs forget their guids after they resume */
2157		sret = drm_dp_dpcd_read(mgr->aux, DP_GUID, guid, 16);
2158		if (sret != 16) {
2159			DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
2160			ret = -1;
2161			goto out_unlock;
2162		}
2163		drm_dp_check_mstb_guid(mgr->mst_primary, guid);
2164
2165		ret = 0;
2166	} else
2167		ret = -1;
2168
2169out_unlock:
2170	mutex_unlock(&mgr->lock);
2171	return ret;
2172}
2173EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
2174
2175static void drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr *mgr, bool up)
2176{
2177	int len;
2178	u8 replyblock[32];
2179	int replylen, origlen, curreply;
2180	int ret;
2181	struct drm_dp_sideband_msg_rx *msg;
2182	int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE : DP_SIDEBAND_MSG_DOWN_REP_BASE;
2183	msg = up ? &mgr->up_req_recv : &mgr->down_rep_recv;
2184
2185	len = min(mgr->max_dpcd_transaction_bytes, 16);
2186	ret = drm_dp_dpcd_read(mgr->aux, basereg,
2187			       replyblock, len);
2188	if (ret != len) {
2189		DRM_DEBUG_KMS("failed to read DPCD down rep %d %d\n", len, ret);
2190		return;
2191	}
2192	ret = drm_dp_sideband_msg_build(msg, replyblock, len, true);
2193	if (!ret) {
2194		DRM_DEBUG_KMS("sideband msg build failed %d\n", replyblock[0]);
2195		return;
2196	}
2197	replylen = msg->curchunk_len + msg->curchunk_hdrlen;
2198
2199	origlen = replylen;
2200	replylen -= len;
2201	curreply = len;
2202	while (replylen > 0) {
2203		len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
2204		ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
2205				    replyblock, len);
2206		if (ret != len) {
2207			DRM_DEBUG_KMS("failed to read a chunk\n");
2208		}
2209		ret = drm_dp_sideband_msg_build(msg, replyblock, len, false);
2210		if (ret == false)
2211			DRM_DEBUG_KMS("failed to build sideband msg\n");
2212		curreply += len;
2213		replylen -= len;
2214	}
2215}
2216
2217static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr *mgr)
2218{
2219	int ret = 0;
2220
2221	drm_dp_get_one_sb_msg(mgr, false);
2222
2223	if (mgr->down_rep_recv.have_eomt) {
2224		struct drm_dp_sideband_msg_tx *txmsg;
2225		struct drm_dp_mst_branch *mstb;
2226		int slot = -1;
2227		mstb = drm_dp_get_mst_branch_device(mgr,
2228						    mgr->down_rep_recv.initial_hdr.lct,
2229						    mgr->down_rep_recv.initial_hdr.rad);
2230
2231		if (!mstb) {
2232			DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->down_rep_recv.initial_hdr.lct);
2233			memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2234			return 0;
2235		}
2236
2237		/* find the message */
2238		slot = mgr->down_rep_recv.initial_hdr.seqno;
2239		mutex_lock(&mgr->qlock);
2240		txmsg = mstb->tx_slots[slot];
2241		/* remove from slots */
2242		mutex_unlock(&mgr->qlock);
2243
2244		if (!txmsg) {
2245			DRM_DEBUG_KMS("Got MST reply with no msg %p %d %d %02x %02x\n",
2246			       mstb,
2247			       mgr->down_rep_recv.initial_hdr.seqno,
2248			       mgr->down_rep_recv.initial_hdr.lct,
2249				      mgr->down_rep_recv.initial_hdr.rad[0],
2250				      mgr->down_rep_recv.msg[0]);
2251			drm_dp_put_mst_branch_device(mstb);
2252			memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2253			return 0;
2254		}
2255
2256		drm_dp_sideband_parse_reply(&mgr->down_rep_recv, &txmsg->reply);
2257		if (txmsg->reply.reply_type == 1) {
2258			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);
2259		}
2260
2261		memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2262		drm_dp_put_mst_branch_device(mstb);
2263
2264		mutex_lock(&mgr->qlock);
2265		txmsg->state = DRM_DP_SIDEBAND_TX_RX;
2266		mstb->tx_slots[slot] = NULL;
2267		mutex_unlock(&mgr->qlock);
2268
2269		wake_up(&mgr->tx_waitq);
2270	}
2271	return ret;
2272}
2273
2274static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
2275{
2276	int ret = 0;
2277	drm_dp_get_one_sb_msg(mgr, true);
2278
2279	if (mgr->up_req_recv.have_eomt) {
2280		struct drm_dp_sideband_msg_req_body msg;
2281		struct drm_dp_mst_branch *mstb = NULL;
2282		bool seqno;
2283
2284		if (!mgr->up_req_recv.initial_hdr.broadcast) {
2285			mstb = drm_dp_get_mst_branch_device(mgr,
2286							    mgr->up_req_recv.initial_hdr.lct,
2287							    mgr->up_req_recv.initial_hdr.rad);
2288			if (!mstb) {
2289				DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
2290				memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2291				return 0;
2292			}
2293		}
2294
2295		seqno = mgr->up_req_recv.initial_hdr.seqno;
2296		drm_dp_sideband_parse_req(&mgr->up_req_recv, &msg);
2297
2298		if (msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
2299			drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, msg.req_type, seqno, false);
2300
2301			if (!mstb)
2302				mstb = drm_dp_get_mst_branch_device_by_guid(mgr, msg.u.conn_stat.guid);
2303
2304			if (!mstb) {
2305				DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
2306				memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2307				return 0;
2308			}
2309
2310			drm_dp_update_port(mstb, &msg.u.conn_stat);
2311
2312			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);
2313			(*mgr->cbs->hotplug)(mgr);
2314
2315		} else if (msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
2316			drm_dp_send_up_ack_reply(mgr, mgr->mst_primary, msg.req_type, seqno, false);
2317			if (!mstb)
2318				mstb = drm_dp_get_mst_branch_device_by_guid(mgr, msg.u.resource_stat.guid);
2319
2320			if (!mstb) {
2321				DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", mgr->up_req_recv.initial_hdr.lct);
2322				memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2323				return 0;
2324			}
2325
2326			DRM_DEBUG_KMS("Got RSN: pn: %d avail_pbn %d\n", msg.u.resource_stat.port_number, msg.u.resource_stat.available_pbn);
2327		}
2328
2329		drm_dp_put_mst_branch_device(mstb);
2330		memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
2331	}
2332	return ret;
2333}
2334
2335/**
2336 * drm_dp_mst_hpd_irq() - MST hotplug IRQ notify
2337 * @mgr: manager to notify irq for.
2338 * @esi: 4 bytes from SINK_COUNT_ESI
2339 * @handled: whether the hpd interrupt was consumed or not
2340 *
2341 * This should be called from the driver when it detects a short IRQ,
2342 * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
2343 * topology manager will process the sideband messages received as a result
2344 * of this.
2345 */
2346int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, bool *handled)
2347{
2348	int ret = 0;
2349	int sc;
2350	*handled = false;
2351	sc = esi[0] & 0x3f;
2352
2353	if (sc != mgr->sink_count) {
2354		mgr->sink_count = sc;
2355		*handled = true;
2356	}
2357
2358	if (esi[1] & DP_DOWN_REP_MSG_RDY) {
2359		ret = drm_dp_mst_handle_down_rep(mgr);
2360		*handled = true;
2361	}
2362
2363	if (esi[1] & DP_UP_REQ_MSG_RDY) {
2364		ret |= drm_dp_mst_handle_up_req(mgr);
2365		*handled = true;
2366	}
2367
2368	drm_dp_mst_kick_tx(mgr);
2369	return ret;
2370}
2371EXPORT_SYMBOL(drm_dp_mst_hpd_irq);
2372
2373/**
2374 * drm_dp_mst_detect_port() - get connection status for an MST port
2375 * @mgr: manager for this port
2376 * @port: unverified pointer to a port
2377 *
2378 * This returns the current connection state for a port. It validates the
2379 * port pointer still exists so the caller doesn't require a reference
2380 */
2381enum drm_connector_status drm_dp_mst_detect_port(struct drm_connector *connector,
2382						 struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2383{
2384	enum drm_connector_status status = connector_status_disconnected;
2385
2386	/* we need to search for the port in the mgr in case its gone */
2387	port = drm_dp_get_validated_port_ref(mgr, port);
2388	if (!port)
2389		return connector_status_disconnected;
2390
2391	if (!port->ddps)
2392		goto out;
2393
2394	switch (port->pdt) {
2395	case DP_PEER_DEVICE_NONE:
2396	case DP_PEER_DEVICE_MST_BRANCHING:
2397		break;
2398
2399	case DP_PEER_DEVICE_SST_SINK:
2400		status = connector_status_connected;
2401		/* for logical ports - cache the EDID */
2402		if (port->port_num >= 8 && !port->cached_edid) {
2403			port->cached_edid = drm_get_edid(connector, &port->aux.ddc);
2404		}
2405		break;
2406	case DP_PEER_DEVICE_DP_LEGACY_CONV:
2407		if (port->ldps)
2408			status = connector_status_connected;
2409		break;
2410	}
2411out:
2412	drm_dp_put_port(port);
2413	return status;
2414}
2415EXPORT_SYMBOL(drm_dp_mst_detect_port);
2416
2417/**
2418 * drm_dp_mst_port_has_audio() - Check whether port has audio capability or not
2419 * @mgr: manager for this port
2420 * @port: unverified pointer to a port.
2421 *
2422 * This returns whether the port supports audio or not.
2423 */
2424bool drm_dp_mst_port_has_audio(struct drm_dp_mst_topology_mgr *mgr,
2425					struct drm_dp_mst_port *port)
2426{
2427	bool ret = false;
2428
2429	port = drm_dp_get_validated_port_ref(mgr, port);
2430	if (!port)
2431		return ret;
2432	ret = port->has_audio;
2433	drm_dp_put_port(port);
2434	return ret;
2435}
2436EXPORT_SYMBOL(drm_dp_mst_port_has_audio);
2437
2438/**
2439 * drm_dp_mst_get_edid() - get EDID for an MST port
2440 * @connector: toplevel connector to get EDID for
2441 * @mgr: manager for this port
2442 * @port: unverified pointer to a port.
2443 *
2444 * This returns an EDID for the port connected to a connector,
2445 * It validates the pointer still exists so the caller doesn't require a
2446 * reference.
2447 */
2448struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2449{
2450	struct edid *edid = NULL;
2451
2452	/* we need to search for the port in the mgr in case its gone */
2453	port = drm_dp_get_validated_port_ref(mgr, port);
2454	if (!port)
2455		return NULL;
2456
2457	if (port->cached_edid)
2458		edid = drm_edid_duplicate(port->cached_edid);
2459	else {
2460		edid = drm_get_edid(connector, &port->aux.ddc);
2461		drm_mode_connector_set_tile_property(connector);
2462	}
2463	port->has_audio = drm_detect_monitor_audio(edid);
2464	drm_dp_put_port(port);
2465	return edid;
2466}
2467EXPORT_SYMBOL(drm_dp_mst_get_edid);
2468
2469/**
2470 * drm_dp_find_vcpi_slots() - find slots for this PBN value
2471 * @mgr: manager to use
2472 * @pbn: payload bandwidth to convert into slots.
2473 */
2474int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
2475			   int pbn)
2476{
2477	int num_slots;
2478
2479	num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
2480
2481	if (num_slots > mgr->avail_slots)
2482		return -ENOSPC;
2483	return num_slots;
2484}
2485EXPORT_SYMBOL(drm_dp_find_vcpi_slots);
2486
2487static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
2488			    struct drm_dp_vcpi *vcpi, int pbn)
2489{
2490	int num_slots;
2491	int ret;
2492
2493	num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
2494
2495	if (num_slots > mgr->avail_slots)
2496		return -ENOSPC;
2497
2498	vcpi->pbn = pbn;
2499	vcpi->aligned_pbn = num_slots * mgr->pbn_div;
2500	vcpi->num_slots = num_slots;
2501
2502	ret = drm_dp_mst_assign_payload_id(mgr, vcpi);
2503	if (ret < 0)
2504		return ret;
2505	return 0;
2506}
2507
2508/**
2509 * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
2510 * @mgr: manager for this port
2511 * @port: port to allocate a virtual channel for.
2512 * @pbn: payload bandwidth number to request
2513 * @slots: returned number of slots for this PBN.
2514 */
2515bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, int pbn, int *slots)
2516{
2517	int ret;
2518
2519	port = drm_dp_get_validated_port_ref(mgr, port);
2520	if (!port)
2521		return false;
2522
2523	if (port->vcpi.vcpi > 0) {
2524		DRM_DEBUG_KMS("payload: vcpi %d already allocated for pbn %d - requested pbn %d\n", port->vcpi.vcpi, port->vcpi.pbn, pbn);
2525		if (pbn == port->vcpi.pbn) {
2526			*slots = port->vcpi.num_slots;
2527			drm_dp_put_port(port);
2528			return true;
2529		}
2530	}
2531
2532	ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn);
2533	if (ret) {
2534		DRM_DEBUG_KMS("failed to init vcpi %d %d %d\n", DIV_ROUND_UP(pbn, mgr->pbn_div), mgr->avail_slots, ret);
2535		goto out;
2536	}
2537	DRM_DEBUG_KMS("initing vcpi for %d %d\n", pbn, port->vcpi.num_slots);
2538	*slots = port->vcpi.num_slots;
2539
2540	drm_dp_put_port(port);
2541	return true;
2542out:
2543	return false;
2544}
2545EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
2546
2547int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2548{
2549	int slots = 0;
2550	port = drm_dp_get_validated_port_ref(mgr, port);
2551	if (!port)
2552		return slots;
2553
2554	slots = port->vcpi.num_slots;
2555	drm_dp_put_port(port);
2556	return slots;
2557}
2558EXPORT_SYMBOL(drm_dp_mst_get_vcpi_slots);
2559
2560/**
2561 * drm_dp_mst_reset_vcpi_slots() - Reset number of slots to 0 for VCPI
2562 * @mgr: manager for this port
2563 * @port: unverified pointer to a port.
2564 *
2565 * This just resets the number of slots for the ports VCPI for later programming.
2566 */
2567void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2568{
2569	port = drm_dp_get_validated_port_ref(mgr, port);
2570	if (!port)
2571		return;
2572	port->vcpi.num_slots = 0;
2573	drm_dp_put_port(port);
2574}
2575EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
2576
2577/**
2578 * drm_dp_mst_deallocate_vcpi() - deallocate a VCPI
2579 * @mgr: manager for this port
2580 * @port: unverified port to deallocate vcpi for
2581 */
2582void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
2583{
2584	port = drm_dp_get_validated_port_ref(mgr, port);
2585	if (!port)
2586		return;
2587
2588	drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
2589	port->vcpi.num_slots = 0;
2590	port->vcpi.pbn = 0;
2591	port->vcpi.aligned_pbn = 0;
2592	port->vcpi.vcpi = 0;
2593	drm_dp_put_port(port);
2594}
2595EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
2596
2597static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
2598				     int id, struct drm_dp_payload *payload)
2599{
2600	u8 payload_alloc[3], status;
2601	int ret;
2602	int retries = 0;
2603
2604	drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
2605			   DP_PAYLOAD_TABLE_UPDATED);
2606
2607	payload_alloc[0] = id;
2608	payload_alloc[1] = payload->start_slot;
2609	payload_alloc[2] = payload->num_slots;
2610
2611	ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, payload_alloc, 3);
2612	if (ret != 3) {
2613		DRM_DEBUG_KMS("failed to write payload allocation %d\n", ret);
2614		goto fail;
2615	}
2616
2617retry:
2618	ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
2619	if (ret < 0) {
2620		DRM_DEBUG_KMS("failed to read payload table status %d\n", ret);
2621		goto fail;
2622	}
2623
2624	if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
2625		retries++;
2626		if (retries < 20) {
2627			usleep_range(10000, 20000);
2628			goto retry;
2629		}
2630		DRM_DEBUG_KMS("status not set after read payload table status %d\n", status);
2631		ret = -EINVAL;
2632		goto fail;
2633	}
2634	ret = 0;
2635fail:
2636	return ret;
2637}
2638
2639
2640/**
2641 * drm_dp_check_act_status() - Check ACT handled status.
2642 * @mgr: manager to use
2643 *
2644 * Check the payload status bits in the DPCD for ACT handled completion.
2645 */
2646int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
2647{
2648	u8 status;
2649	int ret;
2650	int count = 0;
2651
2652	do {
2653		ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
2654
2655		if (ret < 0) {
2656			DRM_DEBUG_KMS("failed to read payload table status %d\n", ret);
2657			goto fail;
2658		}
2659
2660		if (status & DP_PAYLOAD_ACT_HANDLED)
2661			break;
2662		count++;
2663		udelay(100);
2664
2665	} while (count < 30);
2666
2667	if (!(status & DP_PAYLOAD_ACT_HANDLED)) {
2668		DRM_DEBUG_KMS("failed to get ACT bit %d after %d retries\n", status, count);
2669		ret = -EINVAL;
2670		goto fail;
2671	}
2672	return 0;
2673fail:
2674	return ret;
2675}
2676EXPORT_SYMBOL(drm_dp_check_act_status);
2677
2678/**
2679 * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
2680 * @clock: dot clock for the mode
2681 * @bpp: bpp for the mode.
2682 *
2683 * This uses the formula in the spec to calculate the PBN value for a mode.
2684 */
2685int drm_dp_calc_pbn_mode(int clock, int bpp)
2686{
2687	u64 kbps;
2688	s64 peak_kbps;
2689	u32 numerator;
2690	u32 denominator;
2691
2692	kbps = clock * bpp;
2693
2694	/*
2695	 * margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006
2696	 * The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on
2697	 * common multiplier to render an integer PBN for all link rate/lane
2698	 * counts combinations
2699	 * calculate
2700	 * peak_kbps *= (1006/1000)
2701	 * peak_kbps *= (64/54)
2702	 * peak_kbps *= 8    convert to bytes
2703	 */
2704
2705	numerator = 64 * 1006;
2706	denominator = 54 * 8 * 1000 * 1000;
2707
2708	kbps *= numerator;
2709	peak_kbps = drm_fixp_from_fraction(kbps, denominator);
2710
2711	return drm_fixp2int_ceil(peak_kbps);
2712}
2713EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
2714
2715static int test_calc_pbn_mode(void)
2716{
2717	int ret;
2718	ret = drm_dp_calc_pbn_mode(154000, 30);
2719	if (ret != 689) {
2720		DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n",
2721				154000, 30, 689, ret);
2722		return -EINVAL;
2723	}
2724	ret = drm_dp_calc_pbn_mode(234000, 30);
2725	if (ret != 1047) {
2726		DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n",
2727				234000, 30, 1047, ret);
2728		return -EINVAL;
2729	}
2730	ret = drm_dp_calc_pbn_mode(297000, 24);
2731	if (ret != 1063) {
2732		DRM_ERROR("PBN calculation test failed - clock %d, bpp %d, expected PBN %d, actual PBN %d.\n",
2733				297000, 24, 1063, ret);
2734		return -EINVAL;
2735	}
2736	return 0;
2737}
2738
2739/* we want to kick the TX after we've ack the up/down IRQs. */
2740static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
2741{
2742	queue_work(system_long_wq, &mgr->tx_work);
2743}
2744
2745static void drm_dp_mst_dump_mstb(struct seq_file *m,
2746				 struct drm_dp_mst_branch *mstb)
2747{
2748	struct drm_dp_mst_port *port;
2749	int tabs = mstb->lct;
2750	char prefix[10];
2751	int i;
2752
2753	for (i = 0; i < tabs; i++)
2754		prefix[i] = '\t';
2755	prefix[i] = '\0';
2756
2757	seq_printf(m, "%smst: %p, %d\n", prefix, mstb, mstb->num_ports);
2758	list_for_each_entry(port, &mstb->ports, next) {
2759		seq_printf(m, "%sport: %d: ddps: %d ldps: %d, sdp: %d/%d, %p, conn: %p\n", prefix, port->port_num, port->ddps, port->ldps, port->num_sdp_streams, port->num_sdp_stream_sinks, port, port->connector);
2760		if (port->mstb)
2761			drm_dp_mst_dump_mstb(m, port->mstb);
2762	}
2763}
2764
2765static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
2766				  char *buf)
2767{
2768	int ret;
2769	int i;
2770	for (i = 0; i < 4; i++) {
2771		ret = drm_dp_dpcd_read(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS + (i * 16), &buf[i * 16], 16);
2772		if (ret != 16)
2773			break;
2774	}
2775	if (i == 4)
2776		return true;
2777	return false;
2778}
2779
2780/**
2781 * drm_dp_mst_dump_topology(): dump topology to seq file.
2782 * @m: seq_file to dump output to
2783 * @mgr: manager to dump current topology for.
2784 *
2785 * helper to dump MST topology to a seq file for debugfs.
2786 */
2787void drm_dp_mst_dump_topology(struct seq_file *m,
2788			      struct drm_dp_mst_topology_mgr *mgr)
2789{
2790	int i;
2791	struct drm_dp_mst_port *port;
2792	mutex_lock(&mgr->lock);
2793	if (mgr->mst_primary)
2794		drm_dp_mst_dump_mstb(m, mgr->mst_primary);
2795
2796	/* dump VCPIs */
2797	mutex_unlock(&mgr->lock);
2798
2799	mutex_lock(&mgr->payload_lock);
2800	seq_printf(m, "vcpi: %lx %lx\n", mgr->payload_mask, mgr->vcpi_mask);
2801
2802	for (i = 0; i < mgr->max_payloads; i++) {
2803		if (mgr->proposed_vcpis[i]) {
2804			port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
2805			seq_printf(m, "vcpi %d: %d %d %d\n", i, port->port_num, port->vcpi.vcpi, port->vcpi.num_slots);
2806		} else
2807			seq_printf(m, "vcpi %d:unsed\n", i);
2808	}
2809	for (i = 0; i < mgr->max_payloads; i++) {
2810		seq_printf(m, "payload %d: %d, %d, %d\n",
2811			   i,
2812			   mgr->payloads[i].payload_state,
2813			   mgr->payloads[i].start_slot,
2814			   mgr->payloads[i].num_slots);
2815
2816
2817	}
2818	mutex_unlock(&mgr->payload_lock);
2819
2820	mutex_lock(&mgr->lock);
2821	if (mgr->mst_primary) {
2822		u8 buf[64];
2823		bool bret;
2824		int ret;
2825		ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, buf, DP_RECEIVER_CAP_SIZE);
2826		seq_printf(m, "dpcd: ");
2827		for (i = 0; i < DP_RECEIVER_CAP_SIZE; i++)
2828			seq_printf(m, "%02x ", buf[i]);
2829		seq_printf(m, "\n");
2830		ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
2831		seq_printf(m, "faux/mst: ");
2832		for (i = 0; i < 2; i++)
2833			seq_printf(m, "%02x ", buf[i]);
2834		seq_printf(m, "\n");
2835		ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
2836		seq_printf(m, "mst ctrl: ");
2837		for (i = 0; i < 1; i++)
2838			seq_printf(m, "%02x ", buf[i]);
2839		seq_printf(m, "\n");
2840
2841		/* dump the standard OUI branch header */
2842		ret = drm_dp_dpcd_read(mgr->aux, DP_BRANCH_OUI, buf, DP_BRANCH_OUI_HEADER_SIZE);
2843		seq_printf(m, "branch oui: ");
2844		for (i = 0; i < 0x3; i++)
2845			seq_printf(m, "%02x", buf[i]);
2846		seq_printf(m, " devid: ");
2847		for (i = 0x3; i < 0x8; i++)
2848			seq_printf(m, "%c", buf[i]);
2849		seq_printf(m, " revision: hw: %x.%x sw: %x.%x", buf[0x9] >> 4, buf[0x9] & 0xf, buf[0xa], buf[0xb]);
2850		seq_printf(m, "\n");
2851		bret = dump_dp_payload_table(mgr, buf);
2852		if (bret == true) {
2853			seq_printf(m, "payload table: ");
2854			for (i = 0; i < 63; i++)
2855				seq_printf(m, "%02x ", buf[i]);
2856			seq_printf(m, "\n");
2857		}
2858
2859	}
2860
2861	mutex_unlock(&mgr->lock);
2862
2863}
2864EXPORT_SYMBOL(drm_dp_mst_dump_topology);
2865
2866static void drm_dp_tx_work(struct work_struct *work)
2867{
2868	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, tx_work);
2869
2870	mutex_lock(&mgr->qlock);
2871	if (mgr->tx_down_in_progress)
2872		process_single_down_tx_qlock(mgr);
2873	mutex_unlock(&mgr->qlock);
2874}
2875
2876static void drm_dp_free_mst_port(struct kref *kref)
2877{
2878	struct drm_dp_mst_port *port = container_of(kref, struct drm_dp_mst_port, kref);
2879	kref_put(&port->parent->kref, drm_dp_free_mst_branch_device);
2880	kfree(port);
2881}
2882
2883static void drm_dp_destroy_connector_work(struct work_struct *work)
2884{
2885	struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct drm_dp_mst_topology_mgr, destroy_connector_work);
2886	struct drm_dp_mst_port *port;
2887	bool send_hotplug = false;
2888	/*
2889	 * Not a regular list traverse as we have to drop the destroy
2890	 * connector lock before destroying the connector, to avoid AB->BA
2891	 * ordering between this lock and the config mutex.
2892	 */
2893	for (;;) {
2894		mutex_lock(&mgr->destroy_connector_lock);
2895		port = list_first_entry_or_null(&mgr->destroy_connector_list, struct drm_dp_mst_port, next);
2896		if (!port) {
2897			mutex_unlock(&mgr->destroy_connector_lock);
2898			break;
2899		}
2900		list_del(&port->next);
2901		mutex_unlock(&mgr->destroy_connector_lock);
2902
2903		kref_init(&port->kref);
2904		INIT_LIST_HEAD(&port->next);
2905
2906		mgr->cbs->destroy_connector(mgr, port->connector);
2907
2908		drm_dp_port_teardown_pdt(port, port->pdt);
2909
2910		if (!port->input && port->vcpi.vcpi > 0) {
2911			if (mgr->mst_state) {
2912				drm_dp_mst_reset_vcpi_slots(mgr, port);
2913				drm_dp_update_payload_part1(mgr);
2914				drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
2915			}
2916		}
2917
2918		kref_put(&port->kref, drm_dp_free_mst_port);
2919		send_hotplug = true;
2920	}
2921	if (send_hotplug)
2922		(*mgr->cbs->hotplug)(mgr);
2923}
2924
2925/**
2926 * drm_dp_mst_topology_mgr_init - initialise a topology manager
2927 * @mgr: manager struct to initialise
2928 * @dev: device providing this structure - for i2c addition.
2929 * @aux: DP helper aux channel to talk to this device
2930 * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
2931 * @max_payloads: maximum number of payloads this GPU can source
2932 * @conn_base_id: the connector object ID the MST device is connected to.
2933 *
2934 * Return 0 for success, or negative error code on failure
2935 */
2936int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
2937				 struct device *dev, struct drm_dp_aux *aux,
2938				 int max_dpcd_transaction_bytes,
2939				 int max_payloads, int conn_base_id)
2940{
2941	mutex_init(&mgr->lock);
2942	mutex_init(&mgr->qlock);
2943	mutex_init(&mgr->payload_lock);
2944	mutex_init(&mgr->destroy_connector_lock);
2945	INIT_LIST_HEAD(&mgr->tx_msg_downq);
2946	INIT_LIST_HEAD(&mgr->destroy_connector_list);
2947	INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
2948	INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
2949	INIT_WORK(&mgr->destroy_connector_work, drm_dp_destroy_connector_work);
2950	init_waitqueue_head(&mgr->tx_waitq);
2951	mgr->dev = dev;
2952	mgr->aux = aux;
2953	mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
2954	mgr->max_payloads = max_payloads;
2955	mgr->conn_base_id = conn_base_id;
2956	if (max_payloads + 1 > sizeof(mgr->payload_mask) * 8 ||
2957	    max_payloads + 1 > sizeof(mgr->vcpi_mask) * 8)
2958		return -EINVAL;
2959	mgr->payloads = kcalloc(max_payloads, sizeof(struct drm_dp_payload), GFP_KERNEL);
2960	if (!mgr->payloads)
2961		return -ENOMEM;
2962	mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct drm_dp_vcpi *), GFP_KERNEL);
2963	if (!mgr->proposed_vcpis)
2964		return -ENOMEM;
2965	set_bit(0, &mgr->payload_mask);
2966	if (test_calc_pbn_mode() < 0)
2967		DRM_ERROR("MST PBN self-test failed\n");
2968
2969	return 0;
2970}
2971EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
2972
2973/**
2974 * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
2975 * @mgr: manager to destroy
2976 */
2977void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
2978{
2979	flush_work(&mgr->work);
2980	flush_work(&mgr->destroy_connector_work);
2981	mutex_lock(&mgr->payload_lock);
2982	kfree(mgr->payloads);
2983	mgr->payloads = NULL;
2984	kfree(mgr->proposed_vcpis);
2985	mgr->proposed_vcpis = NULL;
2986	mutex_unlock(&mgr->payload_lock);
2987	mgr->dev = NULL;
2988	mgr->aux = NULL;
2989}
2990EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
2991
2992/* I2C device */
2993static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
2994			       int num)
2995{
2996	struct drm_dp_aux *aux = adapter->algo_data;
2997	struct drm_dp_mst_port *port = container_of(aux, struct drm_dp_mst_port, aux);
2998	struct drm_dp_mst_branch *mstb;
2999	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
3000	unsigned int i;
3001	bool reading = false;
3002	struct drm_dp_sideband_msg_req_body msg;
3003	struct drm_dp_sideband_msg_tx *txmsg = NULL;
3004	int ret;
3005
3006	mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
3007	if (!mstb)
3008		return -EREMOTEIO;
3009
3010	/* construct i2c msg */
3011	/* see if last msg is a read */
3012	if (msgs[num - 1].flags & I2C_M_RD)
3013		reading = true;
3014
3015	if (!reading || (num - 1 > DP_REMOTE_I2C_READ_MAX_TRANSACTIONS)) {
3016		DRM_DEBUG_KMS("Unsupported I2C transaction for MST device\n");
3017		ret = -EIO;
3018		goto out;
3019	}
3020
3021	memset(&msg, 0, sizeof(msg));
3022	msg.req_type = DP_REMOTE_I2C_READ;
3023	msg.u.i2c_read.num_transactions = num - 1;
3024	msg.u.i2c_read.port_number = port->port_num;
3025	for (i = 0; i < num - 1; i++) {
3026		msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
3027		msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
3028		msg.u.i2c_read.transactions[i].bytes = msgs[i].buf;
3029	}
3030	msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
3031	msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
3032
3033	txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
3034	if (!txmsg) {
3035		ret = -ENOMEM;
3036		goto out;
3037	}
3038
3039	txmsg->dst = mstb;
3040	drm_dp_encode_sideband_req(&msg, txmsg);
3041
3042	drm_dp_queue_down_tx(mgr, txmsg);
3043
3044	ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
3045	if (ret > 0) {
3046
3047		if (txmsg->reply.reply_type == 1) { /* got a NAK back */
3048			ret = -EREMOTEIO;
3049			goto out;
3050		}
3051		if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
3052			ret = -EIO;
3053			goto out;
3054		}
3055		memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, msgs[num - 1].len);
3056		ret = num;
3057	}
3058out:
3059	kfree(txmsg);
3060	drm_dp_put_mst_branch_device(mstb);
3061	return ret;
3062}
3063
3064static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
3065{
3066	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
3067	       I2C_FUNC_SMBUS_READ_BLOCK_DATA |
3068	       I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
3069	       I2C_FUNC_10BIT_ADDR;
3070}
3071
3072static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
3073	.functionality = drm_dp_mst_i2c_functionality,
3074	.master_xfer = drm_dp_mst_i2c_xfer,
3075};
3076
3077/**
3078 * drm_dp_mst_register_i2c_bus() - register an I2C adapter for I2C-over-AUX
3079 * @aux: DisplayPort AUX channel
3080 *
3081 * Returns 0 on success or a negative error code on failure.
3082 */
3083static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux)
3084{
3085	aux->ddc.algo = &drm_dp_mst_i2c_algo;
3086	aux->ddc.algo_data = aux;
3087	aux->ddc.retries = 3;
3088
3089	aux->ddc.class = I2C_CLASS_DDC;
3090	aux->ddc.owner = THIS_MODULE;
3091	aux->ddc.dev.parent = aux->dev;
3092	aux->ddc.dev.of_node = aux->dev->of_node;
3093
3094	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
3095		sizeof(aux->ddc.name));
3096
3097	return i2c_add_adapter(&aux->ddc);
3098}
3099
3100/**
3101 * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
3102 * @aux: DisplayPort AUX channel
3103 */
3104static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_aux *aux)
3105{
3106	i2c_del_adapter(&aux->ddc);
3107}