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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (c) 2012-2020, The Linux Foundation. All rights reserved.
   4 */
   5
   6#define pr_fmt(fmt)	"[drm-dp] %s: " fmt, __func__
   7
   8#include <drm/drm_print.h>
   9
  10#include "dp_reg.h"
  11#include "dp_link.h"
  12#include "dp_panel.h"
  13
  14#define DP_TEST_REQUEST_MASK		0x7F
  15
  16enum audio_sample_rate {
  17	AUDIO_SAMPLE_RATE_32_KHZ	= 0x00,
  18	AUDIO_SAMPLE_RATE_44_1_KHZ	= 0x01,
  19	AUDIO_SAMPLE_RATE_48_KHZ	= 0x02,
  20	AUDIO_SAMPLE_RATE_88_2_KHZ	= 0x03,
  21	AUDIO_SAMPLE_RATE_96_KHZ	= 0x04,
  22	AUDIO_SAMPLE_RATE_176_4_KHZ	= 0x05,
  23	AUDIO_SAMPLE_RATE_192_KHZ	= 0x06,
  24};
  25
  26enum audio_pattern_type {
  27	AUDIO_TEST_PATTERN_OPERATOR_DEFINED	= 0x00,
  28	AUDIO_TEST_PATTERN_SAWTOOTH		= 0x01,
  29};
  30
  31struct msm_dp_link_request {
  32	u32 test_requested;
  33	u32 test_link_rate;
  34	u32 test_lane_count;
  35};
  36
  37struct msm_dp_link_private {
  38	u32 prev_sink_count;
  39	struct drm_device *drm_dev;
  40	struct drm_dp_aux *aux;
  41	struct msm_dp_link msm_dp_link;
  42
  43	struct msm_dp_link_request request;
  44	struct mutex psm_mutex;
  45	u8 link_status[DP_LINK_STATUS_SIZE];
  46};
  47
  48static int msm_dp_aux_link_power_up(struct drm_dp_aux *aux,
  49					struct msm_dp_link_info *link)
  50{
  51	u8 value;
  52	ssize_t len;
  53	int i;
  54
  55	if (link->revision < 0x11)
  56		return 0;
  57
  58	len = drm_dp_dpcd_readb(aux, DP_SET_POWER, &value);
  59	if (len < 0)
  60		return len;
  61
  62	value &= ~DP_SET_POWER_MASK;
  63	value |= DP_SET_POWER_D0;
  64
  65	/* retry for 1ms to give the sink time to wake up */
  66	for (i = 0; i < 3; i++) {
  67		len = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value);
  68		usleep_range(1000, 2000);
  69		if (len == 1)
  70			break;
  71	}
  72
  73	return 0;
  74}
  75
  76static int msm_dp_aux_link_power_down(struct drm_dp_aux *aux,
  77					struct msm_dp_link_info *link)
  78{
  79	u8 value;
  80	int err;
  81
  82	if (link->revision < 0x11)
  83		return 0;
  84
  85	err = drm_dp_dpcd_readb(aux, DP_SET_POWER, &value);
  86	if (err < 0)
  87		return err;
  88
  89	value &= ~DP_SET_POWER_MASK;
  90	value |= DP_SET_POWER_D3;
  91
  92	err = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value);
  93	if (err < 0)
  94		return err;
  95
  96	return 0;
  97}
  98
  99static int msm_dp_link_get_period(struct msm_dp_link_private *link, int const addr)
 100{
 101	int ret = 0;
 102	u8 data;
 103	u32 const max_audio_period = 0xA;
 104
 105	/* TEST_AUDIO_PERIOD_CH_XX */
 106	if (drm_dp_dpcd_readb(link->aux, addr, &data) < 0) {
 107		DRM_ERROR("failed to read test_audio_period (0x%x)\n", addr);
 108		ret = -EINVAL;
 109		goto exit;
 110	}
 111
 112	/* Period - Bits 3:0 */
 113	data = data & 0xF;
 114	if ((int)data > max_audio_period) {
 115		DRM_ERROR("invalid test_audio_period_ch_1 = 0x%x\n", data);
 116		ret = -EINVAL;
 117		goto exit;
 118	}
 119
 120	ret = data;
 121exit:
 122	return ret;
 123}
 124
 125static int msm_dp_link_parse_audio_channel_period(struct msm_dp_link_private *link)
 126{
 127	int ret = 0;
 128	struct msm_dp_link_test_audio *req = &link->msm_dp_link.test_audio;
 129
 130	ret = msm_dp_link_get_period(link, DP_TEST_AUDIO_PERIOD_CH1);
 131	if (ret == -EINVAL)
 132		goto exit;
 133
 134	req->test_audio_period_ch_1 = ret;
 135	drm_dbg_dp(link->drm_dev, "test_audio_period_ch_1 = 0x%x\n", ret);
 136
 137	ret = msm_dp_link_get_period(link, DP_TEST_AUDIO_PERIOD_CH2);
 138	if (ret == -EINVAL)
 139		goto exit;
 140
 141	req->test_audio_period_ch_2 = ret;
 142	drm_dbg_dp(link->drm_dev, "test_audio_period_ch_2 = 0x%x\n", ret);
 143
 144	/* TEST_AUDIO_PERIOD_CH_3 (Byte 0x275) */
 145	ret = msm_dp_link_get_period(link, DP_TEST_AUDIO_PERIOD_CH3);
 146	if (ret == -EINVAL)
 147		goto exit;
 148
 149	req->test_audio_period_ch_3 = ret;
 150	drm_dbg_dp(link->drm_dev, "test_audio_period_ch_3 = 0x%x\n", ret);
 151
 152	ret = msm_dp_link_get_period(link, DP_TEST_AUDIO_PERIOD_CH4);
 153	if (ret == -EINVAL)
 154		goto exit;
 155
 156	req->test_audio_period_ch_4 = ret;
 157	drm_dbg_dp(link->drm_dev, "test_audio_period_ch_4 = 0x%x\n", ret);
 158
 159	ret = msm_dp_link_get_period(link, DP_TEST_AUDIO_PERIOD_CH5);
 160	if (ret == -EINVAL)
 161		goto exit;
 162
 163	req->test_audio_period_ch_5 = ret;
 164	drm_dbg_dp(link->drm_dev, "test_audio_period_ch_5 = 0x%x\n", ret);
 165
 166	ret = msm_dp_link_get_period(link, DP_TEST_AUDIO_PERIOD_CH6);
 167	if (ret == -EINVAL)
 168		goto exit;
 169
 170	req->test_audio_period_ch_6 = ret;
 171	drm_dbg_dp(link->drm_dev, "test_audio_period_ch_6 = 0x%x\n", ret);
 172
 173	ret = msm_dp_link_get_period(link, DP_TEST_AUDIO_PERIOD_CH7);
 174	if (ret == -EINVAL)
 175		goto exit;
 176
 177	req->test_audio_period_ch_7 = ret;
 178	drm_dbg_dp(link->drm_dev, "test_audio_period_ch_7 = 0x%x\n", ret);
 179
 180	ret = msm_dp_link_get_period(link, DP_TEST_AUDIO_PERIOD_CH8);
 181	if (ret == -EINVAL)
 182		goto exit;
 183
 184	req->test_audio_period_ch_8 = ret;
 185	drm_dbg_dp(link->drm_dev, "test_audio_period_ch_8 = 0x%x\n", ret);
 186exit:
 187	return ret;
 188}
 189
 190static int msm_dp_link_parse_audio_pattern_type(struct msm_dp_link_private *link)
 191{
 192	int ret = 0;
 193	u8 data;
 194	ssize_t rlen;
 195	int const max_audio_pattern_type = 0x1;
 196
 197	rlen = drm_dp_dpcd_readb(link->aux,
 198				DP_TEST_AUDIO_PATTERN_TYPE, &data);
 199	if (rlen < 0) {
 200		DRM_ERROR("failed to read link audio mode. rlen=%zd\n", rlen);
 201		return rlen;
 202	}
 203
 204	/* Audio Pattern Type - Bits 7:0 */
 205	if ((int)data > max_audio_pattern_type) {
 206		DRM_ERROR("invalid audio pattern type = 0x%x\n", data);
 207		ret = -EINVAL;
 208		goto exit;
 209	}
 210
 211	link->msm_dp_link.test_audio.test_audio_pattern_type = data;
 212	drm_dbg_dp(link->drm_dev, "audio pattern type = 0x%x\n", data);
 213exit:
 214	return ret;
 215}
 216
 217static int msm_dp_link_parse_audio_mode(struct msm_dp_link_private *link)
 218{
 219	int ret = 0;
 220	u8 data;
 221	ssize_t rlen;
 222	int const max_audio_sampling_rate = 0x6;
 223	int const max_audio_channel_count = 0x8;
 224	int sampling_rate = 0x0;
 225	int channel_count = 0x0;
 226
 227	rlen = drm_dp_dpcd_readb(link->aux, DP_TEST_AUDIO_MODE, &data);
 228	if (rlen < 0) {
 229		DRM_ERROR("failed to read link audio mode. rlen=%zd\n", rlen);
 230		return rlen;
 231	}
 232
 233	/* Sampling Rate - Bits 3:0 */
 234	sampling_rate = data & 0xF;
 235	if (sampling_rate > max_audio_sampling_rate) {
 236		DRM_ERROR("sampling rate (0x%x) greater than max (0x%x)\n",
 237				sampling_rate, max_audio_sampling_rate);
 238		ret = -EINVAL;
 239		goto exit;
 240	}
 241
 242	/* Channel Count - Bits 7:4 */
 243	channel_count = ((data & 0xF0) >> 4) + 1;
 244	if (channel_count > max_audio_channel_count) {
 245		DRM_ERROR("channel_count (0x%x) greater than max (0x%x)\n",
 246				channel_count, max_audio_channel_count);
 247		ret = -EINVAL;
 248		goto exit;
 249	}
 250
 251	link->msm_dp_link.test_audio.test_audio_sampling_rate = sampling_rate;
 252	link->msm_dp_link.test_audio.test_audio_channel_count = channel_count;
 253	drm_dbg_dp(link->drm_dev,
 254			"sampling_rate = 0x%x, channel_count = 0x%x\n",
 255			sampling_rate, channel_count);
 256exit:
 257	return ret;
 258}
 259
 260static int msm_dp_link_parse_audio_pattern_params(struct msm_dp_link_private *link)
 261{
 262	int ret = 0;
 263
 264	ret = msm_dp_link_parse_audio_mode(link);
 265	if (ret)
 266		goto exit;
 267
 268	ret = msm_dp_link_parse_audio_pattern_type(link);
 269	if (ret)
 270		goto exit;
 271
 272	ret = msm_dp_link_parse_audio_channel_period(link);
 273
 274exit:
 275	return ret;
 276}
 277
 278static bool msm_dp_link_is_video_pattern_valid(u32 pattern)
 279{
 280	switch (pattern) {
 281	case DP_NO_TEST_PATTERN:
 282	case DP_COLOR_RAMP:
 283	case DP_BLACK_AND_WHITE_VERTICAL_LINES:
 284	case DP_COLOR_SQUARE:
 285		return true;
 286	default:
 287		return false;
 288	}
 289}
 290
 291/**
 292 * msm_dp_link_is_bit_depth_valid() - validates the bit depth requested
 293 * @tbd: bit depth requested by the sink
 294 *
 295 * Returns true if the requested bit depth is supported.
 296 */
 297static bool msm_dp_link_is_bit_depth_valid(u32 tbd)
 298{
 299	/* DP_TEST_VIDEO_PATTERN_NONE is treated as invalid */
 300	switch (tbd) {
 301	case DP_TEST_BIT_DEPTH_6:
 302	case DP_TEST_BIT_DEPTH_8:
 303	case DP_TEST_BIT_DEPTH_10:
 304		return true;
 305	default:
 306		return false;
 307	}
 308}
 309
 310static int msm_dp_link_parse_timing_params1(struct msm_dp_link_private *link,
 311					int addr, int len, u32 *val)
 312{
 313	u8 bp[2];
 314	int rlen;
 315
 316	if (len != 2)
 317		return -EINVAL;
 318
 319	/* Read the requested video link pattern (Byte 0x221). */
 320	rlen = drm_dp_dpcd_read(link->aux, addr, bp, len);
 321	if (rlen < len) {
 322		DRM_ERROR("failed to read 0x%x\n", addr);
 323		return -EINVAL;
 324	}
 325
 326	*val = bp[1] | (bp[0] << 8);
 327
 328	return 0;
 329}
 330
 331static int msm_dp_link_parse_timing_params2(struct msm_dp_link_private *link,
 332					int addr, int len,
 333					u32 *val1, u32 *val2)
 334{
 335	u8 bp[2];
 336	int rlen;
 337
 338	if (len != 2)
 339		return -EINVAL;
 340
 341	/* Read the requested video link pattern (Byte 0x221). */
 342	rlen = drm_dp_dpcd_read(link->aux, addr, bp, len);
 343	if (rlen < len) {
 344		DRM_ERROR("failed to read 0x%x\n", addr);
 345		return -EINVAL;
 346	}
 347
 348	*val1 = (bp[0] & BIT(7)) >> 7;
 349	*val2 = bp[1] | ((bp[0] & 0x7F) << 8);
 350
 351	return 0;
 352}
 353
 354static int msm_dp_link_parse_timing_params3(struct msm_dp_link_private *link,
 355					int addr, u32 *val)
 356{
 357	u8 bp;
 358	u32 len = 1;
 359	int rlen;
 360
 361	rlen = drm_dp_dpcd_read(link->aux, addr, &bp, len);
 362	if (rlen < 1) {
 363		DRM_ERROR("failed to read 0x%x\n", addr);
 364		return -EINVAL;
 365	}
 366	*val = bp;
 367
 368	return 0;
 369}
 370
 371/**
 372 * msm_dp_link_parse_video_pattern_params() - parses video pattern parameters from DPCD
 373 * @link: Display Port Driver data
 374 *
 375 * Returns 0 if it successfully parses the video link pattern and the link
 376 * bit depth requested by the sink and, and if the values parsed are valid.
 377 */
 378static int msm_dp_link_parse_video_pattern_params(struct msm_dp_link_private *link)
 379{
 380	int ret = 0;
 381	ssize_t rlen;
 382	u8 bp;
 383
 384	rlen = drm_dp_dpcd_readb(link->aux, DP_TEST_PATTERN, &bp);
 385	if (rlen < 0) {
 386		DRM_ERROR("failed to read link video pattern. rlen=%zd\n",
 387			rlen);
 388		return rlen;
 389	}
 390
 391	if (!msm_dp_link_is_video_pattern_valid(bp)) {
 392		DRM_ERROR("invalid link video pattern = 0x%x\n", bp);
 393		ret = -EINVAL;
 394		return ret;
 395	}
 396
 397	link->msm_dp_link.test_video.test_video_pattern = bp;
 398
 399	/* Read the requested color bit depth and dynamic range (Byte 0x232) */
 400	rlen = drm_dp_dpcd_readb(link->aux, DP_TEST_MISC0, &bp);
 401	if (rlen < 0) {
 402		DRM_ERROR("failed to read link bit depth. rlen=%zd\n", rlen);
 403		return rlen;
 404	}
 405
 406	/* Dynamic Range */
 407	link->msm_dp_link.test_video.test_dyn_range =
 408			(bp & DP_TEST_DYNAMIC_RANGE_CEA);
 409
 410	/* Color bit depth */
 411	bp &= DP_TEST_BIT_DEPTH_MASK;
 412	if (!msm_dp_link_is_bit_depth_valid(bp)) {
 413		DRM_ERROR("invalid link bit depth = 0x%x\n", bp);
 414		ret = -EINVAL;
 415		return ret;
 416	}
 417
 418	link->msm_dp_link.test_video.test_bit_depth = bp;
 419
 420	/* resolution timing params */
 421	ret = msm_dp_link_parse_timing_params1(link, DP_TEST_H_TOTAL_HI, 2,
 422			&link->msm_dp_link.test_video.test_h_total);
 423	if (ret) {
 424		DRM_ERROR("failed to parse test_htotal(DP_TEST_H_TOTAL_HI)\n");
 425		return ret;
 426	}
 427
 428	ret = msm_dp_link_parse_timing_params1(link, DP_TEST_V_TOTAL_HI, 2,
 429			&link->msm_dp_link.test_video.test_v_total);
 430	if (ret) {
 431		DRM_ERROR("failed to parse test_v_total(DP_TEST_V_TOTAL_HI)\n");
 432		return ret;
 433	}
 434
 435	ret = msm_dp_link_parse_timing_params1(link, DP_TEST_H_START_HI, 2,
 436			&link->msm_dp_link.test_video.test_h_start);
 437	if (ret) {
 438		DRM_ERROR("failed to parse test_h_start(DP_TEST_H_START_HI)\n");
 439		return ret;
 440	}
 441
 442	ret = msm_dp_link_parse_timing_params1(link, DP_TEST_V_START_HI, 2,
 443			&link->msm_dp_link.test_video.test_v_start);
 444	if (ret) {
 445		DRM_ERROR("failed to parse test_v_start(DP_TEST_V_START_HI)\n");
 446		return ret;
 447	}
 448
 449	ret = msm_dp_link_parse_timing_params2(link, DP_TEST_HSYNC_HI, 2,
 450			&link->msm_dp_link.test_video.test_hsync_pol,
 451			&link->msm_dp_link.test_video.test_hsync_width);
 452	if (ret) {
 453		DRM_ERROR("failed to parse (DP_TEST_HSYNC_HI)\n");
 454		return ret;
 455	}
 456
 457	ret = msm_dp_link_parse_timing_params2(link, DP_TEST_VSYNC_HI, 2,
 458			&link->msm_dp_link.test_video.test_vsync_pol,
 459			&link->msm_dp_link.test_video.test_vsync_width);
 460	if (ret) {
 461		DRM_ERROR("failed to parse (DP_TEST_VSYNC_HI)\n");
 462		return ret;
 463	}
 464
 465	ret = msm_dp_link_parse_timing_params1(link, DP_TEST_H_WIDTH_HI, 2,
 466			&link->msm_dp_link.test_video.test_h_width);
 467	if (ret) {
 468		DRM_ERROR("failed to parse test_h_width(DP_TEST_H_WIDTH_HI)\n");
 469		return ret;
 470	}
 471
 472	ret = msm_dp_link_parse_timing_params1(link, DP_TEST_V_HEIGHT_HI, 2,
 473			&link->msm_dp_link.test_video.test_v_height);
 474	if (ret) {
 475		DRM_ERROR("failed to parse test_v_height\n");
 476		return ret;
 477	}
 478
 479	ret = msm_dp_link_parse_timing_params3(link, DP_TEST_MISC1,
 480		&link->msm_dp_link.test_video.test_rr_d);
 481	link->msm_dp_link.test_video.test_rr_d &= DP_TEST_REFRESH_DENOMINATOR;
 482	if (ret) {
 483		DRM_ERROR("failed to parse test_rr_d (DP_TEST_MISC1)\n");
 484		return ret;
 485	}
 486
 487	ret = msm_dp_link_parse_timing_params3(link, DP_TEST_REFRESH_RATE_NUMERATOR,
 488		&link->msm_dp_link.test_video.test_rr_n);
 489	if (ret) {
 490		DRM_ERROR("failed to parse test_rr_n\n");
 491		return ret;
 492	}
 493
 494	drm_dbg_dp(link->drm_dev,
 495		"link video pattern = 0x%x\n"
 496		"link dynamic range = 0x%x\n"
 497		"link bit depth = 0x%x\n"
 498		"TEST_H_TOTAL = %d, TEST_V_TOTAL = %d\n"
 499		"TEST_H_START = %d, TEST_V_START = %d\n"
 500		"TEST_HSYNC_POL = %d\n"
 501		"TEST_HSYNC_WIDTH = %d\n"
 502		"TEST_VSYNC_POL = %d\n"
 503		"TEST_VSYNC_WIDTH = %d\n"
 504		"TEST_H_WIDTH = %d\n"
 505		"TEST_V_HEIGHT = %d\n"
 506		"TEST_REFRESH_DENOMINATOR = %d\n"
 507		 "TEST_REFRESH_NUMERATOR = %d\n",
 508		link->msm_dp_link.test_video.test_video_pattern,
 509		link->msm_dp_link.test_video.test_dyn_range,
 510		link->msm_dp_link.test_video.test_bit_depth,
 511		link->msm_dp_link.test_video.test_h_total,
 512		link->msm_dp_link.test_video.test_v_total,
 513		link->msm_dp_link.test_video.test_h_start,
 514		link->msm_dp_link.test_video.test_v_start,
 515		link->msm_dp_link.test_video.test_hsync_pol,
 516		link->msm_dp_link.test_video.test_hsync_width,
 517		link->msm_dp_link.test_video.test_vsync_pol,
 518		link->msm_dp_link.test_video.test_vsync_width,
 519		link->msm_dp_link.test_video.test_h_width,
 520		link->msm_dp_link.test_video.test_v_height,
 521		link->msm_dp_link.test_video.test_rr_d,
 522		link->msm_dp_link.test_video.test_rr_n);
 523
 524	return ret;
 525}
 526
 527/**
 528 * msm_dp_link_parse_link_training_params() - parses link training parameters from
 529 * DPCD
 530 * @link: Display Port Driver data
 531 *
 532 * Returns 0 if it successfully parses the link rate (Byte 0x219) and lane
 533 * count (Byte 0x220), and if these values parse are valid.
 534 */
 535static int msm_dp_link_parse_link_training_params(struct msm_dp_link_private *link)
 536{
 537	u8 bp;
 538	ssize_t rlen;
 539
 540	rlen = drm_dp_dpcd_readb(link->aux, DP_TEST_LINK_RATE,	&bp);
 541	if (rlen < 0) {
 542		DRM_ERROR("failed to read link rate. rlen=%zd\n", rlen);
 543		return rlen;
 544	}
 545
 546	if (!is_link_rate_valid(bp)) {
 547		DRM_ERROR("invalid link rate = 0x%x\n", bp);
 548		return -EINVAL;
 549	}
 550
 551	link->request.test_link_rate = bp;
 552	drm_dbg_dp(link->drm_dev, "link rate = 0x%x\n",
 553				link->request.test_link_rate);
 554
 555	rlen = drm_dp_dpcd_readb(link->aux, DP_TEST_LANE_COUNT, &bp);
 556	if (rlen < 0) {
 557		DRM_ERROR("failed to read lane count. rlen=%zd\n", rlen);
 558		return rlen;
 559	}
 560	bp &= DP_MAX_LANE_COUNT_MASK;
 561
 562	if (!is_lane_count_valid(bp)) {
 563		DRM_ERROR("invalid lane count = 0x%x\n", bp);
 564		return -EINVAL;
 565	}
 566
 567	link->request.test_lane_count = bp;
 568	drm_dbg_dp(link->drm_dev, "lane count = 0x%x\n",
 569				link->request.test_lane_count);
 570	return 0;
 571}
 572
 573/**
 574 * msm_dp_link_parse_phy_test_params() - parses the phy link parameters
 575 * @link: Display Port Driver data
 576 *
 577 * Parses the DPCD (Byte 0x248) for the DP PHY link pattern that is being
 578 * requested.
 579 */
 580static int msm_dp_link_parse_phy_test_params(struct msm_dp_link_private *link)
 581{
 582	u8 data;
 583	ssize_t rlen;
 584
 585	rlen = drm_dp_dpcd_readb(link->aux, DP_PHY_TEST_PATTERN,
 586					&data);
 587	if (rlen < 0) {
 588		DRM_ERROR("failed to read phy link pattern. rlen=%zd\n", rlen);
 589		return rlen;
 590	}
 591
 592	link->msm_dp_link.phy_params.phy_test_pattern_sel = data & 0x07;
 593
 594	drm_dbg_dp(link->drm_dev, "phy_test_pattern_sel = 0x%x\n", data);
 595
 596	switch (data) {
 597	case DP_PHY_TEST_PATTERN_SEL_MASK:
 598	case DP_PHY_TEST_PATTERN_NONE:
 599	case DP_PHY_TEST_PATTERN_D10_2:
 600	case DP_PHY_TEST_PATTERN_ERROR_COUNT:
 601	case DP_PHY_TEST_PATTERN_PRBS7:
 602	case DP_PHY_TEST_PATTERN_80BIT_CUSTOM:
 603	case DP_PHY_TEST_PATTERN_CP2520:
 604		return 0;
 605	default:
 606		return -EINVAL;
 607	}
 608}
 609
 610/**
 611 * msm_dp_link_is_video_audio_test_requested() - checks for audio/video link request
 612 * @link: link requested by the sink
 613 *
 614 * Returns true if the requested link is a permitted audio/video link.
 615 */
 616static bool msm_dp_link_is_video_audio_test_requested(u32 link)
 617{
 618	u8 video_audio_test = (DP_TEST_LINK_VIDEO_PATTERN |
 619				DP_TEST_LINK_AUDIO_PATTERN |
 620				DP_TEST_LINK_AUDIO_DISABLED_VIDEO);
 621
 622	return ((link & video_audio_test) &&
 623		!(link & ~video_audio_test));
 624}
 625
 626/**
 627 * msm_dp_link_parse_request() - parses link request parameters from sink
 628 * @link: Display Port Driver data
 629 *
 630 * Parses the DPCD to check if an automated link is requested (Byte 0x201),
 631 * and what type of link automation is being requested (Byte 0x218).
 632 */
 633static int msm_dp_link_parse_request(struct msm_dp_link_private *link)
 634{
 635	int ret = 0;
 636	u8 data;
 637	ssize_t rlen;
 638
 639	/**
 640	 * Read the device service IRQ vector (Byte 0x201) to determine
 641	 * whether an automated link has been requested by the sink.
 642	 */
 643	rlen = drm_dp_dpcd_readb(link->aux,
 644				DP_DEVICE_SERVICE_IRQ_VECTOR, &data);
 645	if (rlen < 0) {
 646		DRM_ERROR("aux read failed. rlen=%zd\n", rlen);
 647		return rlen;
 648	}
 649
 650	drm_dbg_dp(link->drm_dev, "device service irq vector = 0x%x\n", data);
 651
 652	if (!(data & DP_AUTOMATED_TEST_REQUEST)) {
 653		drm_dbg_dp(link->drm_dev, "no test requested\n");
 654		return 0;
 655	}
 656
 657	/**
 658	 * Read the link request byte (Byte 0x218) to determine what type
 659	 * of automated link has been requested by the sink.
 660	 */
 661	rlen = drm_dp_dpcd_readb(link->aux, DP_TEST_REQUEST, &data);
 662	if (rlen < 0) {
 663		DRM_ERROR("aux read failed. rlen=%zd\n", rlen);
 664		return rlen;
 665	}
 666
 667	if (!data || (data == DP_TEST_LINK_FAUX_PATTERN)) {
 668		drm_dbg_dp(link->drm_dev, "link 0x%x not supported\n", data);
 669		goto end;
 670	}
 671
 672	drm_dbg_dp(link->drm_dev, "Test:(0x%x) requested\n", data);
 673	link->request.test_requested = data;
 674	if (link->request.test_requested == DP_TEST_LINK_PHY_TEST_PATTERN) {
 675		ret = msm_dp_link_parse_phy_test_params(link);
 676		if (ret)
 677			goto end;
 678		ret = msm_dp_link_parse_link_training_params(link);
 679		if (ret)
 680			goto end;
 681	}
 682
 683	if (link->request.test_requested == DP_TEST_LINK_TRAINING) {
 684		ret = msm_dp_link_parse_link_training_params(link);
 685		if (ret)
 686			goto end;
 687	}
 688
 689	if (msm_dp_link_is_video_audio_test_requested(
 690			link->request.test_requested)) {
 691		ret = msm_dp_link_parse_video_pattern_params(link);
 692		if (ret)
 693			goto end;
 694
 695		ret = msm_dp_link_parse_audio_pattern_params(link);
 696	}
 697end:
 698	/*
 699	 * Send a DP_TEST_ACK if all link parameters are valid, otherwise send
 700	 * a DP_TEST_NAK.
 701	 */
 702	if (ret) {
 703		link->msm_dp_link.test_response = DP_TEST_NAK;
 704	} else {
 705		if (link->request.test_requested != DP_TEST_LINK_EDID_READ)
 706			link->msm_dp_link.test_response = DP_TEST_ACK;
 707		else
 708			link->msm_dp_link.test_response =
 709				DP_TEST_EDID_CHECKSUM_WRITE;
 710	}
 711
 712	return ret;
 713}
 714
 715static int msm_dp_link_parse_sink_status_field(struct msm_dp_link_private *link)
 716{
 717	int len;
 718
 719	link->prev_sink_count = link->msm_dp_link.sink_count;
 720	len = drm_dp_read_sink_count(link->aux);
 721	if (len < 0) {
 722		DRM_ERROR("DP parse sink count failed\n");
 723		return len;
 724	}
 725	link->msm_dp_link.sink_count = len;
 726
 727	len = drm_dp_dpcd_read_link_status(link->aux,
 728		link->link_status);
 729	if (len < DP_LINK_STATUS_SIZE) {
 730		DRM_ERROR("DP link status read failed\n");
 731		return len;
 732	}
 733
 734	return msm_dp_link_parse_request(link);
 735}
 736
 737/**
 738 * msm_dp_link_process_link_training_request() - processes new training requests
 739 * @link: Display Port link data
 740 *
 741 * This function will handle new link training requests that are initiated by
 742 * the sink. In particular, it will update the requested lane count and link
 743 * rate, and then trigger the link retraining procedure.
 744 *
 745 * The function will return 0 if a link training request has been processed,
 746 * otherwise it will return -EINVAL.
 747 */
 748static int msm_dp_link_process_link_training_request(struct msm_dp_link_private *link)
 749{
 750	if (link->request.test_requested != DP_TEST_LINK_TRAINING)
 751		return -EINVAL;
 752
 753	drm_dbg_dp(link->drm_dev,
 754			"Test:0x%x link rate = 0x%x, lane count = 0x%x\n",
 755			DP_TEST_LINK_TRAINING,
 756			link->request.test_link_rate,
 757			link->request.test_lane_count);
 758
 759	link->msm_dp_link.link_params.num_lanes = link->request.test_lane_count;
 760	link->msm_dp_link.link_params.rate =
 761		drm_dp_bw_code_to_link_rate(link->request.test_link_rate);
 762
 763	return 0;
 764}
 765
 766bool msm_dp_link_send_test_response(struct msm_dp_link *msm_dp_link)
 767{
 768	struct msm_dp_link_private *link = NULL;
 769	int ret = 0;
 770
 771	if (!msm_dp_link) {
 772		DRM_ERROR("invalid input\n");
 773		return false;
 774	}
 775
 776	link = container_of(msm_dp_link, struct msm_dp_link_private, msm_dp_link);
 777
 778	ret = drm_dp_dpcd_writeb(link->aux, DP_TEST_RESPONSE,
 779			msm_dp_link->test_response);
 780
 781	return ret == 1;
 782}
 783
 784int msm_dp_link_psm_config(struct msm_dp_link *msm_dp_link,
 785			      struct msm_dp_link_info *link_info, bool enable)
 786{
 787	struct msm_dp_link_private *link = NULL;
 788	int ret = 0;
 789
 790	if (!msm_dp_link) {
 791		DRM_ERROR("invalid params\n");
 792		return -EINVAL;
 793	}
 794
 795	link = container_of(msm_dp_link, struct msm_dp_link_private, msm_dp_link);
 796
 797	mutex_lock(&link->psm_mutex);
 798	if (enable)
 799		ret = msm_dp_aux_link_power_down(link->aux, link_info);
 800	else
 801		ret = msm_dp_aux_link_power_up(link->aux, link_info);
 802
 803	if (ret)
 804		DRM_ERROR("Failed to %s low power mode\n", enable ?
 805							"enter" : "exit");
 806
 807	mutex_unlock(&link->psm_mutex);
 808	return ret;
 809}
 810
 811bool msm_dp_link_send_edid_checksum(struct msm_dp_link *msm_dp_link, u8 checksum)
 812{
 813	struct msm_dp_link_private *link = NULL;
 814	int ret = 0;
 815
 816	if (!msm_dp_link) {
 817		DRM_ERROR("invalid input\n");
 818		return false;
 819	}
 820
 821	link = container_of(msm_dp_link, struct msm_dp_link_private, msm_dp_link);
 822
 823	ret = drm_dp_dpcd_writeb(link->aux, DP_TEST_EDID_CHECKSUM,
 824						checksum);
 825	return ret == 1;
 826}
 827
 828static void msm_dp_link_parse_vx_px(struct msm_dp_link_private *link)
 829{
 830	drm_dbg_dp(link->drm_dev, "vx: 0=%d, 1=%d, 2=%d, 3=%d\n",
 831		drm_dp_get_adjust_request_voltage(link->link_status, 0),
 832		drm_dp_get_adjust_request_voltage(link->link_status, 1),
 833		drm_dp_get_adjust_request_voltage(link->link_status, 2),
 834		drm_dp_get_adjust_request_voltage(link->link_status, 3));
 835
 836	drm_dbg_dp(link->drm_dev, "px: 0=%d, 1=%d, 2=%d, 3=%d\n",
 837		drm_dp_get_adjust_request_pre_emphasis(link->link_status, 0),
 838		drm_dp_get_adjust_request_pre_emphasis(link->link_status, 1),
 839		drm_dp_get_adjust_request_pre_emphasis(link->link_status, 2),
 840		drm_dp_get_adjust_request_pre_emphasis(link->link_status, 3));
 841
 842	/**
 843	 * Update the voltage and pre-emphasis levels as per DPCD request
 844	 * vector.
 845	 */
 846	drm_dbg_dp(link->drm_dev,
 847			 "Current: v_level = 0x%x, p_level = 0x%x\n",
 848			link->msm_dp_link.phy_params.v_level,
 849			link->msm_dp_link.phy_params.p_level);
 850	link->msm_dp_link.phy_params.v_level =
 851		drm_dp_get_adjust_request_voltage(link->link_status, 0);
 852	link->msm_dp_link.phy_params.p_level =
 853		drm_dp_get_adjust_request_pre_emphasis(link->link_status, 0);
 854
 855	link->msm_dp_link.phy_params.p_level >>= DP_TRAIN_PRE_EMPHASIS_SHIFT;
 856
 857	drm_dbg_dp(link->drm_dev,
 858			"Requested: v_level = 0x%x, p_level = 0x%x\n",
 859			link->msm_dp_link.phy_params.v_level,
 860			link->msm_dp_link.phy_params.p_level);
 861}
 862
 863/**
 864 * msm_dp_link_process_phy_test_pattern_request() - process new phy link requests
 865 * @link: Display Port Driver data
 866 *
 867 * This function will handle new phy link pattern requests that are initiated
 868 * by the sink. The function will return 0 if a phy link pattern has been
 869 * processed, otherwise it will return -EINVAL.
 870 */
 871static int msm_dp_link_process_phy_test_pattern_request(
 872		struct msm_dp_link_private *link)
 873{
 874	if (!(link->request.test_requested & DP_TEST_LINK_PHY_TEST_PATTERN)) {
 875		drm_dbg_dp(link->drm_dev, "no phy test\n");
 876		return -EINVAL;
 877	}
 878
 879	if (!is_link_rate_valid(link->request.test_link_rate) ||
 880		!is_lane_count_valid(link->request.test_lane_count)) {
 881		DRM_ERROR("Invalid: link rate = 0x%x,lane count = 0x%x\n",
 882				link->request.test_link_rate,
 883				link->request.test_lane_count);
 884		return -EINVAL;
 885	}
 886
 887	drm_dbg_dp(link->drm_dev,
 888			"Current: rate = 0x%x, lane count = 0x%x\n",
 889			link->msm_dp_link.link_params.rate,
 890			link->msm_dp_link.link_params.num_lanes);
 891
 892	drm_dbg_dp(link->drm_dev,
 893			"Requested: rate = 0x%x, lane count = 0x%x\n",
 894			link->request.test_link_rate,
 895			link->request.test_lane_count);
 896
 897	link->msm_dp_link.link_params.num_lanes = link->request.test_lane_count;
 898	link->msm_dp_link.link_params.rate =
 899		drm_dp_bw_code_to_link_rate(link->request.test_link_rate);
 900
 901	msm_dp_link_parse_vx_px(link);
 902
 903	return 0;
 904}
 905
 906static bool msm_dp_link_read_psr_error_status(struct msm_dp_link_private *link)
 907{
 908	u8 status;
 909
 910	drm_dp_dpcd_read(link->aux, DP_PSR_ERROR_STATUS, &status, 1);
 911
 912	if (status & DP_PSR_LINK_CRC_ERROR)
 913		DRM_ERROR("PSR LINK CRC ERROR\n");
 914	else if (status & DP_PSR_RFB_STORAGE_ERROR)
 915		DRM_ERROR("PSR RFB STORAGE ERROR\n");
 916	else if (status & DP_PSR_VSC_SDP_UNCORRECTABLE_ERROR)
 917		DRM_ERROR("PSR VSC SDP UNCORRECTABLE ERROR\n");
 918	else
 919		return false;
 920
 921	return true;
 922}
 923
 924static bool msm_dp_link_psr_capability_changed(struct msm_dp_link_private *link)
 925{
 926	u8 status;
 927
 928	drm_dp_dpcd_read(link->aux, DP_PSR_ESI, &status, 1);
 929
 930	if (status & DP_PSR_CAPS_CHANGE) {
 931		drm_dbg_dp(link->drm_dev, "PSR Capability Change\n");
 932		return true;
 933	}
 934
 935	return false;
 936}
 937
 938static u8 get_link_status(const u8 link_status[DP_LINK_STATUS_SIZE], int r)
 939{
 940	return link_status[r - DP_LANE0_1_STATUS];
 941}
 942
 943/**
 944 * msm_dp_link_process_link_status_update() - processes link status updates
 945 * @link: Display Port link module data
 946 *
 947 * This function will check for changes in the link status, e.g. clock
 948 * recovery done on all lanes, and trigger link training if there is a
 949 * failure/error on the link.
 950 *
 951 * The function will return 0 if the a link status update has been processed,
 952 * otherwise it will return -EINVAL.
 953 */
 954static int msm_dp_link_process_link_status_update(struct msm_dp_link_private *link)
 955{
 956	bool channel_eq_done = drm_dp_channel_eq_ok(link->link_status,
 957			link->msm_dp_link.link_params.num_lanes);
 958
 959	bool clock_recovery_done = drm_dp_clock_recovery_ok(link->link_status,
 960			link->msm_dp_link.link_params.num_lanes);
 961
 962	drm_dbg_dp(link->drm_dev,
 963		       "channel_eq_done = %d, clock_recovery_done = %d\n",
 964                        channel_eq_done, clock_recovery_done);
 965
 966	if (channel_eq_done && clock_recovery_done)
 967		return -EINVAL;
 968
 969	return 0;
 970}
 971
 972/**
 973 * msm_dp_link_process_ds_port_status_change() - process port status changes
 974 * @link: Display Port Driver data
 975 *
 976 * This function will handle downstream port updates that are initiated by
 977 * the sink. If the downstream port status has changed, the EDID is read via
 978 * AUX.
 979 *
 980 * The function will return 0 if a downstream port update has been
 981 * processed, otherwise it will return -EINVAL.
 982 */
 983static int msm_dp_link_process_ds_port_status_change(struct msm_dp_link_private *link)
 984{
 985	if (get_link_status(link->link_status, DP_LANE_ALIGN_STATUS_UPDATED) &
 986					DP_DOWNSTREAM_PORT_STATUS_CHANGED)
 987		goto reset;
 988
 989	if (link->prev_sink_count == link->msm_dp_link.sink_count)
 990		return -EINVAL;
 991
 992reset:
 993	/* reset prev_sink_count */
 994	link->prev_sink_count = link->msm_dp_link.sink_count;
 995
 996	return 0;
 997}
 998
 999static bool msm_dp_link_is_video_pattern_requested(struct msm_dp_link_private *link)
1000{
1001	return (link->request.test_requested & DP_TEST_LINK_VIDEO_PATTERN)
1002		&& !(link->request.test_requested &
1003		DP_TEST_LINK_AUDIO_DISABLED_VIDEO);
1004}
1005
1006static bool msm_dp_link_is_audio_pattern_requested(struct msm_dp_link_private *link)
1007{
1008	return (link->request.test_requested & DP_TEST_LINK_AUDIO_PATTERN);
1009}
1010
1011static void msm_dp_link_reset_data(struct msm_dp_link_private *link)
1012{
1013	link->request = (const struct msm_dp_link_request){ 0 };
1014	link->msm_dp_link.test_video = (const struct msm_dp_link_test_video){ 0 };
1015	link->msm_dp_link.test_video.test_bit_depth = DP_TEST_BIT_DEPTH_UNKNOWN;
1016	link->msm_dp_link.test_audio = (const struct msm_dp_link_test_audio){ 0 };
1017	link->msm_dp_link.phy_params.phy_test_pattern_sel = 0;
1018	link->msm_dp_link.sink_request = 0;
1019	link->msm_dp_link.test_response = 0;
1020}
1021
1022/**
1023 * msm_dp_link_process_request() - handle HPD IRQ transition to HIGH
1024 * @msm_dp_link: pointer to link module data
1025 *
1026 * This function will handle the HPD IRQ state transitions from LOW to HIGH
1027 * (including cases when there are back to back HPD IRQ HIGH) indicating
1028 * the start of a new link training request or sink status update.
1029 */
1030int msm_dp_link_process_request(struct msm_dp_link *msm_dp_link)
1031{
1032	int ret = 0;
1033	struct msm_dp_link_private *link;
1034
1035	if (!msm_dp_link) {
1036		DRM_ERROR("invalid input\n");
1037		return -EINVAL;
1038	}
1039
1040	link = container_of(msm_dp_link, struct msm_dp_link_private, msm_dp_link);
1041
1042	msm_dp_link_reset_data(link);
1043
1044	ret = msm_dp_link_parse_sink_status_field(link);
1045	if (ret)
1046		return ret;
1047
1048	if (link->request.test_requested == DP_TEST_LINK_EDID_READ) {
1049		msm_dp_link->sink_request |= DP_TEST_LINK_EDID_READ;
1050	} else if (!msm_dp_link_process_ds_port_status_change(link)) {
1051		msm_dp_link->sink_request |= DS_PORT_STATUS_CHANGED;
1052	} else if (!msm_dp_link_process_link_training_request(link)) {
1053		msm_dp_link->sink_request |= DP_TEST_LINK_TRAINING;
1054	} else if (!msm_dp_link_process_phy_test_pattern_request(link)) {
1055		msm_dp_link->sink_request |= DP_TEST_LINK_PHY_TEST_PATTERN;
1056	} else if (msm_dp_link_read_psr_error_status(link)) {
1057		DRM_ERROR("PSR IRQ_HPD received\n");
1058	} else if (msm_dp_link_psr_capability_changed(link)) {
1059		drm_dbg_dp(link->drm_dev, "PSR Capability changed\n");
1060	} else {
1061		ret = msm_dp_link_process_link_status_update(link);
1062		if (!ret) {
1063			msm_dp_link->sink_request |= DP_LINK_STATUS_UPDATED;
1064		} else {
1065			if (msm_dp_link_is_video_pattern_requested(link)) {
1066				ret = 0;
1067				msm_dp_link->sink_request |= DP_TEST_LINK_VIDEO_PATTERN;
1068			}
1069			if (msm_dp_link_is_audio_pattern_requested(link)) {
1070				msm_dp_link->sink_request |= DP_TEST_LINK_AUDIO_PATTERN;
1071				ret = -EINVAL;
1072			}
1073		}
1074	}
1075
1076	drm_dbg_dp(link->drm_dev, "sink request=%#x\n",
1077				msm_dp_link->sink_request);
1078	return ret;
1079}
1080
1081int msm_dp_link_get_colorimetry_config(struct msm_dp_link *msm_dp_link)
1082{
1083	u32 cc = DP_MISC0_COLORIMERY_CFG_LEGACY_RGB;
1084	struct msm_dp_link_private *link;
1085
1086	if (!msm_dp_link) {
1087		DRM_ERROR("invalid input\n");
1088		return -EINVAL;
1089	}
1090
1091	link = container_of(msm_dp_link, struct msm_dp_link_private, msm_dp_link);
1092
1093	/*
1094	 * Unless a video pattern CTS test is ongoing, use RGB_VESA
1095	 * Only RGB_VESA and RGB_CEA supported for now
1096	 */
1097	if (msm_dp_link_is_video_pattern_requested(link)) {
1098		if (link->msm_dp_link.test_video.test_dyn_range &
1099					DP_TEST_DYNAMIC_RANGE_CEA)
1100			cc = DP_MISC0_COLORIMERY_CFG_CEA_RGB;
1101	}
1102
1103	return cc;
1104}
1105
1106int msm_dp_link_adjust_levels(struct msm_dp_link *msm_dp_link, u8 *link_status)
1107{
1108	int i;
1109	u8 max_p_level;
1110	int v_max = 0, p_max = 0;
1111	struct msm_dp_link_private *link;
1112
1113	if (!msm_dp_link) {
1114		DRM_ERROR("invalid input\n");
1115		return -EINVAL;
1116	}
1117
1118	link = container_of(msm_dp_link, struct msm_dp_link_private, msm_dp_link);
1119
1120	/* use the max level across lanes */
1121	for (i = 0; i < msm_dp_link->link_params.num_lanes; i++) {
1122		u8 data_v = drm_dp_get_adjust_request_voltage(link_status, i);
1123		u8 data_p = drm_dp_get_adjust_request_pre_emphasis(link_status,
1124									 i);
1125		drm_dbg_dp(link->drm_dev,
1126				"lane=%d req_vol_swing=%d req_pre_emphasis=%d\n",
1127				i, data_v, data_p);
1128		if (v_max < data_v)
1129			v_max = data_v;
1130		if (p_max < data_p)
1131			p_max = data_p;
1132	}
1133
1134	msm_dp_link->phy_params.v_level = v_max >> DP_TRAIN_VOLTAGE_SWING_SHIFT;
1135	msm_dp_link->phy_params.p_level = p_max >> DP_TRAIN_PRE_EMPHASIS_SHIFT;
1136
1137	/**
1138	 * Adjust the voltage swing and pre-emphasis level combination to within
1139	 * the allowable range.
1140	 */
1141	if (msm_dp_link->phy_params.v_level > DP_TRAIN_LEVEL_MAX) {
1142		drm_dbg_dp(link->drm_dev,
1143			"Requested vSwingLevel=%d, change to %d\n",
1144			msm_dp_link->phy_params.v_level,
1145			DP_TRAIN_LEVEL_MAX);
1146		msm_dp_link->phy_params.v_level = DP_TRAIN_LEVEL_MAX;
1147	}
1148
1149	if (msm_dp_link->phy_params.p_level > DP_TRAIN_LEVEL_MAX) {
1150		drm_dbg_dp(link->drm_dev,
1151			"Requested preEmphasisLevel=%d, change to %d\n",
1152			msm_dp_link->phy_params.p_level,
1153			DP_TRAIN_LEVEL_MAX);
1154		msm_dp_link->phy_params.p_level = DP_TRAIN_LEVEL_MAX;
1155	}
1156
1157	max_p_level = DP_TRAIN_LEVEL_MAX - msm_dp_link->phy_params.v_level;
1158	if (msm_dp_link->phy_params.p_level > max_p_level) {
1159		drm_dbg_dp(link->drm_dev,
1160			"Requested preEmphasisLevel=%d, change to %d\n",
1161			msm_dp_link->phy_params.p_level,
1162			max_p_level);
1163		msm_dp_link->phy_params.p_level = max_p_level;
1164	}
1165
1166	drm_dbg_dp(link->drm_dev, "adjusted: v_level=%d, p_level=%d\n",
1167		msm_dp_link->phy_params.v_level, msm_dp_link->phy_params.p_level);
1168
1169	return 0;
1170}
1171
1172void msm_dp_link_reset_phy_params_vx_px(struct msm_dp_link *msm_dp_link)
1173{
1174	msm_dp_link->phy_params.v_level = 0;
1175	msm_dp_link->phy_params.p_level = 0;
1176}
1177
1178u32 msm_dp_link_get_test_bits_depth(struct msm_dp_link *msm_dp_link, u32 bpp)
1179{
1180	u32 tbd;
1181	struct msm_dp_link_private *link;
1182
1183	link = container_of(msm_dp_link, struct msm_dp_link_private, msm_dp_link);
1184
1185	/*
1186	 * Few simplistic rules and assumptions made here:
1187	 *    1. Test bit depth is bit depth per color component
1188	 *    2. Assume 3 color components
1189	 */
1190	switch (bpp) {
1191	case 18:
1192		tbd = DP_TEST_BIT_DEPTH_6;
1193		break;
1194	case 24:
1195		tbd = DP_TEST_BIT_DEPTH_8;
1196		break;
1197	case 30:
1198		tbd = DP_TEST_BIT_DEPTH_10;
1199		break;
1200	default:
1201		drm_dbg_dp(link->drm_dev, "bpp=%d not supported, use bpc=8\n",
1202			   bpp);
1203		tbd = DP_TEST_BIT_DEPTH_8;
1204		break;
1205	}
1206
1207	tbd = (tbd >> DP_TEST_BIT_DEPTH_SHIFT);
1208
1209	return tbd;
1210}
1211
1212struct msm_dp_link *msm_dp_link_get(struct device *dev, struct drm_dp_aux *aux)
1213{
1214	struct msm_dp_link_private *link;
1215	struct msm_dp_link *msm_dp_link;
1216
1217	if (!dev || !aux) {
1218		DRM_ERROR("invalid input\n");
1219		return ERR_PTR(-EINVAL);
1220	}
1221
1222	link = devm_kzalloc(dev, sizeof(*link), GFP_KERNEL);
1223	if (!link)
1224		return ERR_PTR(-ENOMEM);
1225
1226	link->aux   = aux;
1227
1228	mutex_init(&link->psm_mutex);
1229	msm_dp_link = &link->msm_dp_link;
1230
1231	return msm_dp_link;
1232}