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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 
16 enum 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 
26 enum audio_pattern_type {
27 	AUDIO_TEST_PATTERN_OPERATOR_DEFINED	= 0x00,
28 	AUDIO_TEST_PATTERN_SAWTOOTH		= 0x01,
29 };
30 
31 struct dp_link_request {
32 	u32 test_requested;
33 	u32 test_link_rate;
34 	u32 test_lane_count;
35 };
36 
37 struct dp_link_private {
38 	u32 prev_sink_count;
39 	struct device *dev;
40 	struct drm_dp_aux *aux;
41 	struct dp_link dp_link;
42 
43 	struct dp_link_request request;
44 	struct mutex psm_mutex;
45 	u8 link_status[DP_LINK_STATUS_SIZE];
46 };
47 
dp_aux_link_power_up(struct drm_dp_aux * aux,struct dp_link_info * link)48 static int dp_aux_link_power_up(struct drm_dp_aux *aux,
49 					struct dp_link_info *link)
50 {
51 	u8 value;
52 	int err;
53 
54 	if (link->revision < 0x11)
55 		return 0;
56 
57 	err = drm_dp_dpcd_readb(aux, DP_SET_POWER, &value);
58 	if (err < 0)
59 		return err;
60 
61 	value &= ~DP_SET_POWER_MASK;
62 	value |= DP_SET_POWER_D0;
63 
64 	err = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value);
65 	if (err < 0)
66 		return err;
67 
68 	usleep_range(1000, 2000);
69 
70 	return 0;
71 }
72 
dp_aux_link_power_down(struct drm_dp_aux * aux,struct dp_link_info * link)73 static int dp_aux_link_power_down(struct drm_dp_aux *aux,
74 					struct dp_link_info *link)
75 {
76 	u8 value;
77 	int err;
78 
79 	if (link->revision < 0x11)
80 		return 0;
81 
82 	err = drm_dp_dpcd_readb(aux, DP_SET_POWER, &value);
83 	if (err < 0)
84 		return err;
85 
86 	value &= ~DP_SET_POWER_MASK;
87 	value |= DP_SET_POWER_D3;
88 
89 	err = drm_dp_dpcd_writeb(aux, DP_SET_POWER, value);
90 	if (err < 0)
91 		return err;
92 
93 	return 0;
94 }
95 
dp_link_get_period(struct dp_link_private * link,int const addr)96 static int dp_link_get_period(struct dp_link_private *link, int const addr)
97 {
98 	int ret = 0;
99 	u8 data;
100 	u32 const max_audio_period = 0xA;
101 
102 	/* TEST_AUDIO_PERIOD_CH_XX */
103 	if (drm_dp_dpcd_readb(link->aux, addr, &data) < 0) {
104 		DRM_ERROR("failed to read test_audio_period (0x%x)\n", addr);
105 		ret = -EINVAL;
106 		goto exit;
107 	}
108 
109 	/* Period - Bits 3:0 */
110 	data = data & 0xF;
111 	if ((int)data > max_audio_period) {
112 		DRM_ERROR("invalid test_audio_period_ch_1 = 0x%x\n", data);
113 		ret = -EINVAL;
114 		goto exit;
115 	}
116 
117 	ret = data;
118 exit:
119 	return ret;
120 }
121 
dp_link_parse_audio_channel_period(struct dp_link_private * link)122 static int dp_link_parse_audio_channel_period(struct dp_link_private *link)
123 {
124 	int ret = 0;
125 	struct dp_link_test_audio *req = &link->dp_link.test_audio;
126 
127 	ret = dp_link_get_period(link, DP_TEST_AUDIO_PERIOD_CH1);
128 	if (ret == -EINVAL)
129 		goto exit;
130 
131 	req->test_audio_period_ch_1 = ret;
132 	DRM_DEBUG_DP("test_audio_period_ch_1 = 0x%x\n", ret);
133 
134 	ret = dp_link_get_period(link, DP_TEST_AUDIO_PERIOD_CH2);
135 	if (ret == -EINVAL)
136 		goto exit;
137 
138 	req->test_audio_period_ch_2 = ret;
139 	DRM_DEBUG_DP("test_audio_period_ch_2 = 0x%x\n", ret);
140 
141 	/* TEST_AUDIO_PERIOD_CH_3 (Byte 0x275) */
142 	ret = dp_link_get_period(link, DP_TEST_AUDIO_PERIOD_CH3);
143 	if (ret == -EINVAL)
144 		goto exit;
145 
146 	req->test_audio_period_ch_3 = ret;
147 	DRM_DEBUG_DP("test_audio_period_ch_3 = 0x%x\n", ret);
148 
149 	ret = dp_link_get_period(link, DP_TEST_AUDIO_PERIOD_CH4);
150 	if (ret == -EINVAL)
151 		goto exit;
152 
153 	req->test_audio_period_ch_4 = ret;
154 	DRM_DEBUG_DP("test_audio_period_ch_4 = 0x%x\n", ret);
155 
156 	ret = dp_link_get_period(link, DP_TEST_AUDIO_PERIOD_CH5);
157 	if (ret == -EINVAL)
158 		goto exit;
159 
160 	req->test_audio_period_ch_5 = ret;
161 	DRM_DEBUG_DP("test_audio_period_ch_5 = 0x%x\n", ret);
162 
163 	ret = dp_link_get_period(link, DP_TEST_AUDIO_PERIOD_CH6);
164 	if (ret == -EINVAL)
165 		goto exit;
166 
167 	req->test_audio_period_ch_6 = ret;
168 	DRM_DEBUG_DP("test_audio_period_ch_6 = 0x%x\n", ret);
169 
170 	ret = dp_link_get_period(link, DP_TEST_AUDIO_PERIOD_CH7);
171 	if (ret == -EINVAL)
172 		goto exit;
173 
174 	req->test_audio_period_ch_7 = ret;
175 	DRM_DEBUG_DP("test_audio_period_ch_7 = 0x%x\n", ret);
176 
177 	ret = dp_link_get_period(link, DP_TEST_AUDIO_PERIOD_CH8);
178 	if (ret == -EINVAL)
179 		goto exit;
180 
181 	req->test_audio_period_ch_8 = ret;
182 	DRM_DEBUG_DP("test_audio_period_ch_8 = 0x%x\n", ret);
183 exit:
184 	return ret;
185 }
186 
dp_link_parse_audio_pattern_type(struct dp_link_private * link)187 static int dp_link_parse_audio_pattern_type(struct dp_link_private *link)
188 {
189 	int ret = 0;
190 	u8 data;
191 	ssize_t rlen;
192 	int const max_audio_pattern_type = 0x1;
193 
194 	rlen = drm_dp_dpcd_readb(link->aux,
195 				DP_TEST_AUDIO_PATTERN_TYPE, &data);
196 	if (rlen < 0) {
197 		DRM_ERROR("failed to read link audio mode. rlen=%zd\n", rlen);
198 		return rlen;
199 	}
200 
201 	/* Audio Pattern Type - Bits 7:0 */
202 	if ((int)data > max_audio_pattern_type) {
203 		DRM_ERROR("invalid audio pattern type = 0x%x\n", data);
204 		ret = -EINVAL;
205 		goto exit;
206 	}
207 
208 	link->dp_link.test_audio.test_audio_pattern_type = data;
209 	DRM_DEBUG_DP("audio pattern type = 0x%x\n", data);
210 exit:
211 	return ret;
212 }
213 
dp_link_parse_audio_mode(struct dp_link_private * link)214 static int dp_link_parse_audio_mode(struct dp_link_private *link)
215 {
216 	int ret = 0;
217 	u8 data;
218 	ssize_t rlen;
219 	int const max_audio_sampling_rate = 0x6;
220 	int const max_audio_channel_count = 0x8;
221 	int sampling_rate = 0x0;
222 	int channel_count = 0x0;
223 
224 	rlen = drm_dp_dpcd_readb(link->aux, DP_TEST_AUDIO_MODE, &data);
225 	if (rlen < 0) {
226 		DRM_ERROR("failed to read link audio mode. rlen=%zd\n", rlen);
227 		return rlen;
228 	}
229 
230 	/* Sampling Rate - Bits 3:0 */
231 	sampling_rate = data & 0xF;
232 	if (sampling_rate > max_audio_sampling_rate) {
233 		DRM_ERROR("sampling rate (0x%x) greater than max (0x%x)\n",
234 				sampling_rate, max_audio_sampling_rate);
235 		ret = -EINVAL;
236 		goto exit;
237 	}
238 
239 	/* Channel Count - Bits 7:4 */
240 	channel_count = ((data & 0xF0) >> 4) + 1;
241 	if (channel_count > max_audio_channel_count) {
242 		DRM_ERROR("channel_count (0x%x) greater than max (0x%x)\n",
243 				channel_count, max_audio_channel_count);
244 		ret = -EINVAL;
245 		goto exit;
246 	}
247 
248 	link->dp_link.test_audio.test_audio_sampling_rate = sampling_rate;
249 	link->dp_link.test_audio.test_audio_channel_count = channel_count;
250 	DRM_DEBUG_DP("sampling_rate = 0x%x, channel_count = 0x%x\n",
251 					sampling_rate, channel_count);
252 exit:
253 	return ret;
254 }
255 
dp_link_parse_audio_pattern_params(struct dp_link_private * link)256 static int dp_link_parse_audio_pattern_params(struct dp_link_private *link)
257 {
258 	int ret = 0;
259 
260 	ret = dp_link_parse_audio_mode(link);
261 	if (ret)
262 		goto exit;
263 
264 	ret = dp_link_parse_audio_pattern_type(link);
265 	if (ret)
266 		goto exit;
267 
268 	ret = dp_link_parse_audio_channel_period(link);
269 
270 exit:
271 	return ret;
272 }
273 
dp_link_is_video_pattern_valid(u32 pattern)274 static bool dp_link_is_video_pattern_valid(u32 pattern)
275 {
276 	switch (pattern) {
277 	case DP_NO_TEST_PATTERN:
278 	case DP_COLOR_RAMP:
279 	case DP_BLACK_AND_WHITE_VERTICAL_LINES:
280 	case DP_COLOR_SQUARE:
281 		return true;
282 	default:
283 		return false;
284 	}
285 }
286 
287 /**
288  * dp_link_is_bit_depth_valid() - validates the bit depth requested
289  * @tbd: bit depth requested by the sink
290  *
291  * Returns true if the requested bit depth is supported.
292  */
dp_link_is_bit_depth_valid(u32 tbd)293 static bool dp_link_is_bit_depth_valid(u32 tbd)
294 {
295 	/* DP_TEST_VIDEO_PATTERN_NONE is treated as invalid */
296 	switch (tbd) {
297 	case DP_TEST_BIT_DEPTH_6:
298 	case DP_TEST_BIT_DEPTH_8:
299 	case DP_TEST_BIT_DEPTH_10:
300 		return true;
301 	default:
302 		return false;
303 	}
304 }
305 
dp_link_parse_timing_params1(struct dp_link_private * link,int addr,int len,u32 * val)306 static int dp_link_parse_timing_params1(struct dp_link_private *link,
307 					int addr, int len, u32 *val)
308 {
309 	u8 bp[2];
310 	int rlen;
311 
312 	if (len != 2)
313 		return -EINVAL;
314 
315 	/* Read the requested video link pattern (Byte 0x221). */
316 	rlen = drm_dp_dpcd_read(link->aux, addr, bp, len);
317 	if (rlen < len) {
318 		DRM_ERROR("failed to read 0x%x\n", addr);
319 		return -EINVAL;
320 	}
321 
322 	*val = bp[1] | (bp[0] << 8);
323 
324 	return 0;
325 }
326 
dp_link_parse_timing_params2(struct dp_link_private * link,int addr,int len,u32 * val1,u32 * val2)327 static int dp_link_parse_timing_params2(struct dp_link_private *link,
328 					int addr, int len,
329 					u32 *val1, u32 *val2)
330 {
331 	u8 bp[2];
332 	int rlen;
333 
334 	if (len != 2)
335 		return -EINVAL;
336 
337 	/* Read the requested video link pattern (Byte 0x221). */
338 	rlen = drm_dp_dpcd_read(link->aux, addr, bp, len);
339 	if (rlen < len) {
340 		DRM_ERROR("failed to read 0x%x\n", addr);
341 		return -EINVAL;
342 	}
343 
344 	*val1 = (bp[0] & BIT(7)) >> 7;
345 	*val2 = bp[1] | ((bp[0] & 0x7F) << 8);
346 
347 	return 0;
348 }
349 
dp_link_parse_timing_params3(struct dp_link_private * link,int addr,u32 * val)350 static int dp_link_parse_timing_params3(struct dp_link_private *link,
351 					int addr, u32 *val)
352 {
353 	u8 bp;
354 	u32 len = 1;
355 	int rlen;
356 
357 	rlen = drm_dp_dpcd_read(link->aux, addr, &bp, len);
358 	if (rlen < 1) {
359 		DRM_ERROR("failed to read 0x%x\n", addr);
360 		return -EINVAL;
361 	}
362 	*val = bp;
363 
364 	return 0;
365 }
366 
367 /**
368  * dp_parse_video_pattern_params() - parses video pattern parameters from DPCD
369  * @link: Display Port Driver data
370  *
371  * Returns 0 if it successfully parses the video link pattern and the link
372  * bit depth requested by the sink and, and if the values parsed are valid.
373  */
dp_link_parse_video_pattern_params(struct dp_link_private * link)374 static int dp_link_parse_video_pattern_params(struct dp_link_private *link)
375 {
376 	int ret = 0;
377 	ssize_t rlen;
378 	u8 bp;
379 
380 	rlen = drm_dp_dpcd_readb(link->aux, DP_TEST_PATTERN, &bp);
381 	if (rlen < 0) {
382 		DRM_ERROR("failed to read link video pattern. rlen=%zd\n",
383 			rlen);
384 		return rlen;
385 	}
386 
387 	if (!dp_link_is_video_pattern_valid(bp)) {
388 		DRM_ERROR("invalid link video pattern = 0x%x\n", bp);
389 		ret = -EINVAL;
390 		return ret;
391 	}
392 
393 	link->dp_link.test_video.test_video_pattern = bp;
394 
395 	/* Read the requested color bit depth and dynamic range (Byte 0x232) */
396 	rlen = drm_dp_dpcd_readb(link->aux, DP_TEST_MISC0, &bp);
397 	if (rlen < 0) {
398 		DRM_ERROR("failed to read link bit depth. rlen=%zd\n", rlen);
399 		return rlen;
400 	}
401 
402 	/* Dynamic Range */
403 	link->dp_link.test_video.test_dyn_range =
404 			(bp & DP_TEST_DYNAMIC_RANGE_CEA);
405 
406 	/* Color bit depth */
407 	bp &= DP_TEST_BIT_DEPTH_MASK;
408 	if (!dp_link_is_bit_depth_valid(bp)) {
409 		DRM_ERROR("invalid link bit depth = 0x%x\n", bp);
410 		ret = -EINVAL;
411 		return ret;
412 	}
413 
414 	link->dp_link.test_video.test_bit_depth = bp;
415 
416 	/* resolution timing params */
417 	ret = dp_link_parse_timing_params1(link, DP_TEST_H_TOTAL_HI, 2,
418 			&link->dp_link.test_video.test_h_total);
419 	if (ret) {
420 		DRM_ERROR("failed to parse test_htotal(DP_TEST_H_TOTAL_HI)\n");
421 		return ret;
422 	}
423 
424 	ret = dp_link_parse_timing_params1(link, DP_TEST_V_TOTAL_HI, 2,
425 			&link->dp_link.test_video.test_v_total);
426 	if (ret) {
427 		DRM_ERROR("failed to parse test_v_total(DP_TEST_V_TOTAL_HI)\n");
428 		return ret;
429 	}
430 
431 	ret = dp_link_parse_timing_params1(link, DP_TEST_H_START_HI, 2,
432 			&link->dp_link.test_video.test_h_start);
433 	if (ret) {
434 		DRM_ERROR("failed to parse test_h_start(DP_TEST_H_START_HI)\n");
435 		return ret;
436 	}
437 
438 	ret = dp_link_parse_timing_params1(link, DP_TEST_V_START_HI, 2,
439 			&link->dp_link.test_video.test_v_start);
440 	if (ret) {
441 		DRM_ERROR("failed to parse test_v_start(DP_TEST_V_START_HI)\n");
442 		return ret;
443 	}
444 
445 	ret = dp_link_parse_timing_params2(link, DP_TEST_HSYNC_HI, 2,
446 			&link->dp_link.test_video.test_hsync_pol,
447 			&link->dp_link.test_video.test_hsync_width);
448 	if (ret) {
449 		DRM_ERROR("failed to parse (DP_TEST_HSYNC_HI)\n");
450 		return ret;
451 	}
452 
453 	ret = dp_link_parse_timing_params2(link, DP_TEST_VSYNC_HI, 2,
454 			&link->dp_link.test_video.test_vsync_pol,
455 			&link->dp_link.test_video.test_vsync_width);
456 	if (ret) {
457 		DRM_ERROR("failed to parse (DP_TEST_VSYNC_HI)\n");
458 		return ret;
459 	}
460 
461 	ret = dp_link_parse_timing_params1(link, DP_TEST_H_WIDTH_HI, 2,
462 			&link->dp_link.test_video.test_h_width);
463 	if (ret) {
464 		DRM_ERROR("failed to parse test_h_width(DP_TEST_H_WIDTH_HI)\n");
465 		return ret;
466 	}
467 
468 	ret = dp_link_parse_timing_params1(link, DP_TEST_V_HEIGHT_HI, 2,
469 			&link->dp_link.test_video.test_v_height);
470 	if (ret) {
471 		DRM_ERROR("failed to parse test_v_height\n");
472 		return ret;
473 	}
474 
475 	ret = dp_link_parse_timing_params3(link, DP_TEST_MISC1,
476 		&link->dp_link.test_video.test_rr_d);
477 	link->dp_link.test_video.test_rr_d &= DP_TEST_REFRESH_DENOMINATOR;
478 	if (ret) {
479 		DRM_ERROR("failed to parse test_rr_d (DP_TEST_MISC1)\n");
480 		return ret;
481 	}
482 
483 	ret = dp_link_parse_timing_params3(link, DP_TEST_REFRESH_RATE_NUMERATOR,
484 		&link->dp_link.test_video.test_rr_n);
485 	if (ret) {
486 		DRM_ERROR("failed to parse test_rr_n\n");
487 		return ret;
488 	}
489 
490 	DRM_DEBUG_DP("link video pattern = 0x%x\n"
491 		"link dynamic range = 0x%x\n"
492 		"link bit depth = 0x%x\n"
493 		"TEST_H_TOTAL = %d, TEST_V_TOTAL = %d\n"
494 		"TEST_H_START = %d, TEST_V_START = %d\n"
495 		"TEST_HSYNC_POL = %d\n"
496 		"TEST_HSYNC_WIDTH = %d\n"
497 		"TEST_VSYNC_POL = %d\n"
498 		"TEST_VSYNC_WIDTH = %d\n"
499 		"TEST_H_WIDTH = %d\n"
500 		"TEST_V_HEIGHT = %d\n"
501 		"TEST_REFRESH_DENOMINATOR = %d\n"
502 		 "TEST_REFRESH_NUMERATOR = %d\n",
503 		link->dp_link.test_video.test_video_pattern,
504 		link->dp_link.test_video.test_dyn_range,
505 		link->dp_link.test_video.test_bit_depth,
506 		link->dp_link.test_video.test_h_total,
507 		link->dp_link.test_video.test_v_total,
508 		link->dp_link.test_video.test_h_start,
509 		link->dp_link.test_video.test_v_start,
510 		link->dp_link.test_video.test_hsync_pol,
511 		link->dp_link.test_video.test_hsync_width,
512 		link->dp_link.test_video.test_vsync_pol,
513 		link->dp_link.test_video.test_vsync_width,
514 		link->dp_link.test_video.test_h_width,
515 		link->dp_link.test_video.test_v_height,
516 		link->dp_link.test_video.test_rr_d,
517 		link->dp_link.test_video.test_rr_n);
518 
519 	return ret;
520 }
521 
522 /**
523  * dp_link_parse_link_training_params() - parses link training parameters from
524  * DPCD
525  * @link: Display Port Driver data
526  *
527  * Returns 0 if it successfully parses the link rate (Byte 0x219) and lane
528  * count (Byte 0x220), and if these values parse are valid.
529  */
dp_link_parse_link_training_params(struct dp_link_private * link)530 static int dp_link_parse_link_training_params(struct dp_link_private *link)
531 {
532 	u8 bp;
533 	ssize_t rlen;
534 
535 	rlen = drm_dp_dpcd_readb(link->aux, DP_TEST_LINK_RATE,	&bp);
536 	if (rlen < 0) {
537 		DRM_ERROR("failed to read link rate. rlen=%zd\n", rlen);
538 		return rlen;
539 	}
540 
541 	if (!is_link_rate_valid(bp)) {
542 		DRM_ERROR("invalid link rate = 0x%x\n", bp);
543 		return -EINVAL;
544 	}
545 
546 	link->request.test_link_rate = bp;
547 	DRM_DEBUG_DP("link rate = 0x%x\n", link->request.test_link_rate);
548 
549 	rlen = drm_dp_dpcd_readb(link->aux, DP_TEST_LANE_COUNT, &bp);
550 	if (rlen < 0) {
551 		DRM_ERROR("failed to read lane count. rlen=%zd\n", rlen);
552 		return rlen;
553 	}
554 	bp &= DP_MAX_LANE_COUNT_MASK;
555 
556 	if (!is_lane_count_valid(bp)) {
557 		DRM_ERROR("invalid lane count = 0x%x\n", bp);
558 		return -EINVAL;
559 	}
560 
561 	link->request.test_lane_count = bp;
562 	DRM_DEBUG_DP("lane count = 0x%x\n", link->request.test_lane_count);
563 	return 0;
564 }
565 
566 /**
567  * dp_parse_phy_test_params() - parses the phy link parameters
568  * @link: Display Port Driver data
569  *
570  * Parses the DPCD (Byte 0x248) for the DP PHY link pattern that is being
571  * requested.
572  */
dp_link_parse_phy_test_params(struct dp_link_private * link)573 static int dp_link_parse_phy_test_params(struct dp_link_private *link)
574 {
575 	u8 data;
576 	ssize_t rlen;
577 
578 	rlen = drm_dp_dpcd_readb(link->aux, DP_PHY_TEST_PATTERN,
579 					&data);
580 	if (rlen < 0) {
581 		DRM_ERROR("failed to read phy link pattern. rlen=%zd\n", rlen);
582 		return rlen;
583 	}
584 
585 	link->dp_link.phy_params.phy_test_pattern_sel = data & 0x07;
586 
587 	DRM_DEBUG_DP("phy_test_pattern_sel = 0x%x\n", data);
588 
589 	switch (data) {
590 	case DP_PHY_TEST_PATTERN_SEL_MASK:
591 	case DP_PHY_TEST_PATTERN_NONE:
592 	case DP_PHY_TEST_PATTERN_D10_2:
593 	case DP_PHY_TEST_PATTERN_ERROR_COUNT:
594 	case DP_PHY_TEST_PATTERN_PRBS7:
595 	case DP_PHY_TEST_PATTERN_80BIT_CUSTOM:
596 	case DP_PHY_TEST_PATTERN_CP2520:
597 		return 0;
598 	default:
599 		return -EINVAL;
600 	}
601 }
602 
603 /**
604  * dp_link_is_video_audio_test_requested() - checks for audio/video link request
605  * @link: link requested by the sink
606  *
607  * Returns true if the requested link is a permitted audio/video link.
608  */
dp_link_is_video_audio_test_requested(u32 link)609 static bool dp_link_is_video_audio_test_requested(u32 link)
610 {
611 	u8 video_audio_test = (DP_TEST_LINK_VIDEO_PATTERN |
612 				DP_TEST_LINK_AUDIO_PATTERN |
613 				DP_TEST_LINK_AUDIO_DISABLED_VIDEO);
614 
615 	return ((link & video_audio_test) &&
616 		!(link & ~video_audio_test));
617 }
618 
619 /**
620  * dp_link_parse_request() - parses link request parameters from sink
621  * @link: Display Port Driver data
622  *
623  * Parses the DPCD to check if an automated link is requested (Byte 0x201),
624  * and what type of link automation is being requested (Byte 0x218).
625  */
dp_link_parse_request(struct dp_link_private * link)626 static int dp_link_parse_request(struct dp_link_private *link)
627 {
628 	int ret = 0;
629 	u8 data;
630 	ssize_t rlen;
631 
632 	/**
633 	 * Read the device service IRQ vector (Byte 0x201) to determine
634 	 * whether an automated link has been requested by the sink.
635 	 */
636 	rlen = drm_dp_dpcd_readb(link->aux,
637 				DP_DEVICE_SERVICE_IRQ_VECTOR, &data);
638 	if (rlen < 0) {
639 		DRM_ERROR("aux read failed. rlen=%zd\n", rlen);
640 		return rlen;
641 	}
642 
643 	DRM_DEBUG_DP("device service irq vector = 0x%x\n", data);
644 
645 	if (!(data & DP_AUTOMATED_TEST_REQUEST)) {
646 		DRM_DEBUG_DP("no test requested\n");
647 		return 0;
648 	}
649 
650 	/**
651 	 * Read the link request byte (Byte 0x218) to determine what type
652 	 * of automated link has been requested by the sink.
653 	 */
654 	rlen = drm_dp_dpcd_readb(link->aux, DP_TEST_REQUEST, &data);
655 	if (rlen < 0) {
656 		DRM_ERROR("aux read failed. rlen=%zd\n", rlen);
657 		return rlen;
658 	}
659 
660 	if (!data || (data == DP_TEST_LINK_FAUX_PATTERN)) {
661 		DRM_DEBUG_DP("link 0x%x not supported\n", data);
662 		goto end;
663 	}
664 
665 	DRM_DEBUG_DP("Test:(0x%x) requested\n", data);
666 	link->request.test_requested = data;
667 	if (link->request.test_requested == DP_TEST_LINK_PHY_TEST_PATTERN) {
668 		ret = dp_link_parse_phy_test_params(link);
669 		if (ret)
670 			goto end;
671 		ret = dp_link_parse_link_training_params(link);
672 		if (ret)
673 			goto end;
674 	}
675 
676 	if (link->request.test_requested == DP_TEST_LINK_TRAINING) {
677 		ret = dp_link_parse_link_training_params(link);
678 		if (ret)
679 			goto end;
680 	}
681 
682 	if (dp_link_is_video_audio_test_requested(
683 			link->request.test_requested)) {
684 		ret = dp_link_parse_video_pattern_params(link);
685 		if (ret)
686 			goto end;
687 
688 		ret = dp_link_parse_audio_pattern_params(link);
689 	}
690 end:
691 	/*
692 	 * Send a DP_TEST_ACK if all link parameters are valid, otherwise send
693 	 * a DP_TEST_NAK.
694 	 */
695 	if (ret) {
696 		link->dp_link.test_response = DP_TEST_NAK;
697 	} else {
698 		if (link->request.test_requested != DP_TEST_LINK_EDID_READ)
699 			link->dp_link.test_response = DP_TEST_ACK;
700 		else
701 			link->dp_link.test_response =
702 				DP_TEST_EDID_CHECKSUM_WRITE;
703 	}
704 
705 	return ret;
706 }
707 
708 /**
709  * dp_link_parse_sink_count() - parses the sink count
710  * @dp_link: pointer to link module data
711  *
712  * Parses the DPCD to check if there is an update to the sink count
713  * (Byte 0x200), and whether all the sink devices connected have Content
714  * Protection enabled.
715  */
dp_link_parse_sink_count(struct dp_link * dp_link)716 static int dp_link_parse_sink_count(struct dp_link *dp_link)
717 {
718 	ssize_t rlen;
719 	bool cp_ready;
720 
721 	struct dp_link_private *link = container_of(dp_link,
722 			struct dp_link_private, dp_link);
723 
724 	rlen = drm_dp_dpcd_readb(link->aux, DP_SINK_COUNT,
725 				 &link->dp_link.sink_count);
726 	if (rlen < 0) {
727 		DRM_ERROR("sink count read failed. rlen=%zd\n", rlen);
728 		return rlen;
729 	}
730 
731 	cp_ready = link->dp_link.sink_count & DP_SINK_CP_READY;
732 
733 	link->dp_link.sink_count =
734 		DP_GET_SINK_COUNT(link->dp_link.sink_count);
735 
736 	DRM_DEBUG_DP("sink_count = 0x%x, cp_ready = 0x%x\n",
737 		link->dp_link.sink_count, cp_ready);
738 	return 0;
739 }
740 
dp_link_parse_sink_status_field(struct dp_link_private * link)741 static void dp_link_parse_sink_status_field(struct dp_link_private *link)
742 {
743 	int len = 0;
744 
745 	link->prev_sink_count = link->dp_link.sink_count;
746 	dp_link_parse_sink_count(&link->dp_link);
747 
748 	len = drm_dp_dpcd_read_link_status(link->aux,
749 		link->link_status);
750 	if (len < DP_LINK_STATUS_SIZE)
751 		DRM_ERROR("DP link status read failed\n");
752 	dp_link_parse_request(link);
753 }
754 
755 /**
756  * dp_link_process_link_training_request() - processes new training requests
757  * @link: Display Port link data
758  *
759  * This function will handle new link training requests that are initiated by
760  * the sink. In particular, it will update the requested lane count and link
761  * rate, and then trigger the link retraining procedure.
762  *
763  * The function will return 0 if a link training request has been processed,
764  * otherwise it will return -EINVAL.
765  */
dp_link_process_link_training_request(struct dp_link_private * link)766 static int dp_link_process_link_training_request(struct dp_link_private *link)
767 {
768 	if (link->request.test_requested != DP_TEST_LINK_TRAINING)
769 		return -EINVAL;
770 
771 	DRM_DEBUG_DP("Test:0x%x link rate = 0x%x, lane count = 0x%x\n",
772 			DP_TEST_LINK_TRAINING,
773 			link->request.test_link_rate,
774 			link->request.test_lane_count);
775 
776 	link->dp_link.link_params.num_lanes = link->request.test_lane_count;
777 	link->dp_link.link_params.rate =
778 		drm_dp_bw_code_to_link_rate(link->request.test_link_rate);
779 
780 	return 0;
781 }
782 
dp_link_send_test_response(struct dp_link * dp_link)783 bool dp_link_send_test_response(struct dp_link *dp_link)
784 {
785 	struct dp_link_private *link = NULL;
786 	int ret = 0;
787 
788 	if (!dp_link) {
789 		DRM_ERROR("invalid input\n");
790 		return false;
791 	}
792 
793 	link = container_of(dp_link, struct dp_link_private, dp_link);
794 
795 	ret = drm_dp_dpcd_writeb(link->aux, DP_TEST_RESPONSE,
796 			dp_link->test_response);
797 
798 	return ret == 1;
799 }
800 
dp_link_psm_config(struct dp_link * dp_link,struct dp_link_info * link_info,bool enable)801 int dp_link_psm_config(struct dp_link *dp_link,
802 			      struct dp_link_info *link_info, bool enable)
803 {
804 	struct dp_link_private *link = NULL;
805 	int ret = 0;
806 
807 	if (!dp_link) {
808 		DRM_ERROR("invalid params\n");
809 		return -EINVAL;
810 	}
811 
812 	link = container_of(dp_link, struct dp_link_private, dp_link);
813 
814 	mutex_lock(&link->psm_mutex);
815 	if (enable)
816 		ret = dp_aux_link_power_down(link->aux, link_info);
817 	else
818 		ret = dp_aux_link_power_up(link->aux, link_info);
819 
820 	if (ret)
821 		DRM_ERROR("Failed to %s low power mode\n", enable ?
822 							"enter" : "exit");
823 	else
824 		dp_link->psm_enabled = enable;
825 
826 	mutex_unlock(&link->psm_mutex);
827 	return ret;
828 }
829 
dp_link_send_edid_checksum(struct dp_link * dp_link,u8 checksum)830 bool dp_link_send_edid_checksum(struct dp_link *dp_link, u8 checksum)
831 {
832 	struct dp_link_private *link = NULL;
833 	int ret = 0;
834 
835 	if (!dp_link) {
836 		DRM_ERROR("invalid input\n");
837 		return false;
838 	}
839 
840 	link = container_of(dp_link, struct dp_link_private, dp_link);
841 
842 	ret = drm_dp_dpcd_writeb(link->aux, DP_TEST_EDID_CHECKSUM,
843 						checksum);
844 	return ret == 1;
845 }
846 
dp_link_parse_vx_px(struct dp_link_private * link)847 static int dp_link_parse_vx_px(struct dp_link_private *link)
848 {
849 	int ret = 0;
850 
851 	DRM_DEBUG_DP("vx: 0=%d, 1=%d, 2=%d, 3=%d\n",
852 		drm_dp_get_adjust_request_voltage(link->link_status, 0),
853 		drm_dp_get_adjust_request_voltage(link->link_status, 1),
854 		drm_dp_get_adjust_request_voltage(link->link_status, 2),
855 		drm_dp_get_adjust_request_voltage(link->link_status, 3));
856 
857 	DRM_DEBUG_DP("px: 0=%d, 1=%d, 2=%d, 3=%d\n",
858 		drm_dp_get_adjust_request_pre_emphasis(link->link_status, 0),
859 		drm_dp_get_adjust_request_pre_emphasis(link->link_status, 1),
860 		drm_dp_get_adjust_request_pre_emphasis(link->link_status, 2),
861 		drm_dp_get_adjust_request_pre_emphasis(link->link_status, 3));
862 
863 	/**
864 	 * Update the voltage and pre-emphasis levels as per DPCD request
865 	 * vector.
866 	 */
867 	DRM_DEBUG_DP("Current: v_level = 0x%x, p_level = 0x%x\n",
868 			link->dp_link.phy_params.v_level,
869 			link->dp_link.phy_params.p_level);
870 	link->dp_link.phy_params.v_level =
871 		drm_dp_get_adjust_request_voltage(link->link_status, 0);
872 	link->dp_link.phy_params.p_level =
873 		drm_dp_get_adjust_request_pre_emphasis(link->link_status, 0);
874 
875 	link->dp_link.phy_params.p_level >>= DP_TRAIN_PRE_EMPHASIS_SHIFT;
876 
877 	DRM_DEBUG_DP("Requested: v_level = 0x%x, p_level = 0x%x\n",
878 			link->dp_link.phy_params.v_level,
879 			link->dp_link.phy_params.p_level);
880 
881 	return ret;
882 }
883 
884 /**
885  * dp_link_process_phy_test_pattern_request() - process new phy link requests
886  * @link: Display Port Driver data
887  *
888  * This function will handle new phy link pattern requests that are initiated
889  * by the sink. The function will return 0 if a phy link pattern has been
890  * processed, otherwise it will return -EINVAL.
891  */
dp_link_process_phy_test_pattern_request(struct dp_link_private * link)892 static int dp_link_process_phy_test_pattern_request(
893 		struct dp_link_private *link)
894 {
895 	int ret = 0;
896 
897 	if (!(link->request.test_requested & DP_TEST_LINK_PHY_TEST_PATTERN)) {
898 		DRM_DEBUG_DP("no phy test\n");
899 		return -EINVAL;
900 	}
901 
902 	if (!is_link_rate_valid(link->request.test_link_rate) ||
903 		!is_lane_count_valid(link->request.test_lane_count)) {
904 		DRM_ERROR("Invalid: link rate = 0x%x,lane count = 0x%x\n",
905 				link->request.test_link_rate,
906 				link->request.test_lane_count);
907 		return -EINVAL;
908 	}
909 
910 	DRM_DEBUG_DP("Current: rate = 0x%x, lane count = 0x%x\n",
911 			link->dp_link.link_params.rate,
912 			link->dp_link.link_params.num_lanes);
913 
914 	DRM_DEBUG_DP("Requested: rate = 0x%x, lane count = 0x%x\n",
915 			link->request.test_link_rate,
916 			link->request.test_lane_count);
917 
918 	link->dp_link.link_params.num_lanes = link->request.test_lane_count;
919 	link->dp_link.link_params.rate =
920 		drm_dp_bw_code_to_link_rate(link->request.test_link_rate);
921 
922 	ret = dp_link_parse_vx_px(link);
923 
924 	if (ret)
925 		DRM_ERROR("parse_vx_px failed. ret=%d\n", ret);
926 
927 	return ret;
928 }
929 
get_link_status(const u8 link_status[DP_LINK_STATUS_SIZE],int r)930 static u8 get_link_status(const u8 link_status[DP_LINK_STATUS_SIZE], int r)
931 {
932 	return link_status[r - DP_LANE0_1_STATUS];
933 }
934 
935 /**
936  * dp_link_process_link_status_update() - processes link status updates
937  * @link: Display Port link module data
938  *
939  * This function will check for changes in the link status, e.g. clock
940  * recovery done on all lanes, and trigger link training if there is a
941  * failure/error on the link.
942  *
943  * The function will return 0 if the a link status update has been processed,
944  * otherwise it will return -EINVAL.
945  */
dp_link_process_link_status_update(struct dp_link_private * link)946 static int dp_link_process_link_status_update(struct dp_link_private *link)
947 {
948        bool channel_eq_done = drm_dp_channel_eq_ok(link->link_status,
949                        link->dp_link.link_params.num_lanes);
950 
951        bool clock_recovery_done = drm_dp_clock_recovery_ok(link->link_status,
952                        link->dp_link.link_params.num_lanes);
953 
954        DRM_DEBUG_DP("channel_eq_done = %d, clock_recovery_done = %d\n",
955                         channel_eq_done, clock_recovery_done);
956 
957        if (channel_eq_done && clock_recovery_done)
958                return -EINVAL;
959 
960 
961        return 0;
962 }
963 
964 /**
965  * dp_link_process_downstream_port_status_change() - process port status changes
966  * @link: Display Port Driver data
967  *
968  * This function will handle downstream port updates that are initiated by
969  * the sink. If the downstream port status has changed, the EDID is read via
970  * AUX.
971  *
972  * The function will return 0 if a downstream port update has been
973  * processed, otherwise it will return -EINVAL.
974  */
dp_link_process_ds_port_status_change(struct dp_link_private * link)975 static int dp_link_process_ds_port_status_change(struct dp_link_private *link)
976 {
977 	if (get_link_status(link->link_status, DP_LANE_ALIGN_STATUS_UPDATED) &
978 					DP_DOWNSTREAM_PORT_STATUS_CHANGED)
979 		goto reset;
980 
981 	if (link->prev_sink_count == link->dp_link.sink_count)
982 		return -EINVAL;
983 
984 reset:
985 	/* reset prev_sink_count */
986 	link->prev_sink_count = link->dp_link.sink_count;
987 
988 	return 0;
989 }
990 
dp_link_is_video_pattern_requested(struct dp_link_private * link)991 static bool dp_link_is_video_pattern_requested(struct dp_link_private *link)
992 {
993 	return (link->request.test_requested & DP_TEST_LINK_VIDEO_PATTERN)
994 		&& !(link->request.test_requested &
995 		DP_TEST_LINK_AUDIO_DISABLED_VIDEO);
996 }
997 
dp_link_is_audio_pattern_requested(struct dp_link_private * link)998 static bool dp_link_is_audio_pattern_requested(struct dp_link_private *link)
999 {
1000 	return (link->request.test_requested & DP_TEST_LINK_AUDIO_PATTERN);
1001 }
1002 
dp_link_reset_data(struct dp_link_private * link)1003 static void dp_link_reset_data(struct dp_link_private *link)
1004 {
1005 	link->request = (const struct dp_link_request){ 0 };
1006 	link->dp_link.test_video = (const struct dp_link_test_video){ 0 };
1007 	link->dp_link.test_video.test_bit_depth = DP_TEST_BIT_DEPTH_UNKNOWN;
1008 	link->dp_link.test_audio = (const struct dp_link_test_audio){ 0 };
1009 	link->dp_link.phy_params.phy_test_pattern_sel = 0;
1010 	link->dp_link.sink_request = 0;
1011 	link->dp_link.test_response = 0;
1012 }
1013 
1014 /**
1015  * dp_link_process_request() - handle HPD IRQ transition to HIGH
1016  * @dp_link: pointer to link module data
1017  *
1018  * This function will handle the HPD IRQ state transitions from LOW to HIGH
1019  * (including cases when there are back to back HPD IRQ HIGH) indicating
1020  * the start of a new link training request or sink status update.
1021  */
dp_link_process_request(struct dp_link * dp_link)1022 int dp_link_process_request(struct dp_link *dp_link)
1023 {
1024 	int ret = 0;
1025 	struct dp_link_private *link;
1026 
1027 	if (!dp_link) {
1028 		DRM_ERROR("invalid input\n");
1029 		return -EINVAL;
1030 	}
1031 
1032 	link = container_of(dp_link, struct dp_link_private, dp_link);
1033 
1034 	dp_link_reset_data(link);
1035 
1036 	dp_link_parse_sink_status_field(link);
1037 
1038 	if (link->request.test_requested == DP_TEST_LINK_EDID_READ) {
1039 		dp_link->sink_request |= DP_TEST_LINK_EDID_READ;
1040 		return ret;
1041 	}
1042 
1043 	ret = dp_link_process_ds_port_status_change(link);
1044 	if (!ret) {
1045 		dp_link->sink_request |= DS_PORT_STATUS_CHANGED;
1046 		return ret;
1047 	}
1048 
1049 	ret = dp_link_process_link_training_request(link);
1050 	if (!ret) {
1051 		dp_link->sink_request |= DP_TEST_LINK_TRAINING;
1052 		return ret;
1053 	}
1054 
1055 	ret = dp_link_process_phy_test_pattern_request(link);
1056 	if (!ret) {
1057 		dp_link->sink_request |= DP_TEST_LINK_PHY_TEST_PATTERN;
1058 		return ret;
1059 	}
1060 
1061 	ret = dp_link_process_link_status_update(link);
1062 	if (!ret) {
1063 		dp_link->sink_request |= DP_LINK_STATUS_UPDATED;
1064 		return ret;
1065 	}
1066 
1067 	if (dp_link_is_video_pattern_requested(link)) {
1068 		ret = 0;
1069 		dp_link->sink_request |= DP_TEST_LINK_VIDEO_PATTERN;
1070 	}
1071 
1072 	if (dp_link_is_audio_pattern_requested(link)) {
1073 		dp_link->sink_request |= DP_TEST_LINK_AUDIO_PATTERN;
1074 		return -EINVAL;
1075 	}
1076 
1077 	return ret;
1078 }
1079 
dp_link_get_colorimetry_config(struct dp_link * dp_link)1080 int dp_link_get_colorimetry_config(struct dp_link *dp_link)
1081 {
1082 	u32 cc = DP_MISC0_COLORIMERY_CFG_LEGACY_RGB;
1083 	struct dp_link_private *link;
1084 
1085 	if (!dp_link) {
1086 		DRM_ERROR("invalid input\n");
1087 		return -EINVAL;
1088 	}
1089 
1090 	link = container_of(dp_link, struct dp_link_private, dp_link);
1091 
1092 	/*
1093 	 * Unless a video pattern CTS test is ongoing, use RGB_VESA
1094 	 * Only RGB_VESA and RGB_CEA supported for now
1095 	 */
1096 	if (dp_link_is_video_pattern_requested(link)) {
1097 		if (link->dp_link.test_video.test_dyn_range &
1098 					DP_TEST_DYNAMIC_RANGE_CEA)
1099 			cc = DP_MISC0_COLORIMERY_CFG_CEA_RGB;
1100 	}
1101 
1102 	return cc;
1103 }
1104 
dp_link_adjust_levels(struct dp_link * dp_link,u8 * link_status)1105 int dp_link_adjust_levels(struct dp_link *dp_link, u8 *link_status)
1106 {
1107 	int i;
1108 	int v_max = 0, p_max = 0;
1109 
1110 	if (!dp_link) {
1111 		DRM_ERROR("invalid input\n");
1112 		return -EINVAL;
1113 	}
1114 
1115 	/* use the max level across lanes */
1116 	for (i = 0; i < dp_link->link_params.num_lanes; i++) {
1117 		u8 data_v = drm_dp_get_adjust_request_voltage(link_status, i);
1118 		u8 data_p = drm_dp_get_adjust_request_pre_emphasis(link_status,
1119 									 i);
1120 		DRM_DEBUG_DP("lane=%d req_vol_swing=%d req_pre_emphasis=%d\n",
1121 				i, data_v, data_p);
1122 		if (v_max < data_v)
1123 			v_max = data_v;
1124 		if (p_max < data_p)
1125 			p_max = data_p;
1126 	}
1127 
1128 	dp_link->phy_params.v_level = v_max >> DP_TRAIN_VOLTAGE_SWING_SHIFT;
1129 	dp_link->phy_params.p_level = p_max >> DP_TRAIN_PRE_EMPHASIS_SHIFT;
1130 
1131 	/**
1132 	 * Adjust the voltage swing and pre-emphasis level combination to within
1133 	 * the allowable range.
1134 	 */
1135 	if (dp_link->phy_params.v_level > DP_TRAIN_VOLTAGE_SWING_MAX) {
1136 		DRM_DEBUG_DP("Requested vSwingLevel=%d, change to %d\n",
1137 			dp_link->phy_params.v_level,
1138 			DP_TRAIN_VOLTAGE_SWING_MAX);
1139 		dp_link->phy_params.v_level = DP_TRAIN_VOLTAGE_SWING_MAX;
1140 	}
1141 
1142 	if (dp_link->phy_params.p_level > DP_TRAIN_PRE_EMPHASIS_MAX) {
1143 		DRM_DEBUG_DP("Requested preEmphasisLevel=%d, change to %d\n",
1144 			dp_link->phy_params.p_level,
1145 			DP_TRAIN_PRE_EMPHASIS_MAX);
1146 		dp_link->phy_params.p_level = DP_TRAIN_PRE_EMPHASIS_MAX;
1147 	}
1148 
1149 	if ((dp_link->phy_params.p_level > DP_TRAIN_PRE_EMPHASIS_LVL_1)
1150 		&& (dp_link->phy_params.v_level ==
1151 			DP_TRAIN_VOLTAGE_SWING_LVL_2)) {
1152 		DRM_DEBUG_DP("Requested preEmphasisLevel=%d, change to %d\n",
1153 			dp_link->phy_params.p_level,
1154 			DP_TRAIN_PRE_EMPHASIS_LVL_1);
1155 		dp_link->phy_params.p_level = DP_TRAIN_PRE_EMPHASIS_LVL_1;
1156 	}
1157 
1158 	DRM_DEBUG_DP("adjusted: v_level=%d, p_level=%d\n",
1159 		dp_link->phy_params.v_level, dp_link->phy_params.p_level);
1160 
1161 	return 0;
1162 }
1163 
dp_link_reset_phy_params_vx_px(struct dp_link * dp_link)1164 void dp_link_reset_phy_params_vx_px(struct dp_link *dp_link)
1165 {
1166 	dp_link->phy_params.v_level = 0;
1167 	dp_link->phy_params.p_level = 0;
1168 }
1169 
dp_link_get_test_bits_depth(struct dp_link * dp_link,u32 bpp)1170 u32 dp_link_get_test_bits_depth(struct dp_link *dp_link, u32 bpp)
1171 {
1172 	u32 tbd;
1173 
1174 	/*
1175 	 * Few simplistic rules and assumptions made here:
1176 	 *    1. Test bit depth is bit depth per color component
1177 	 *    2. Assume 3 color components
1178 	 */
1179 	switch (bpp) {
1180 	case 18:
1181 		tbd = DP_TEST_BIT_DEPTH_6;
1182 		break;
1183 	case 24:
1184 		tbd = DP_TEST_BIT_DEPTH_8;
1185 		break;
1186 	case 30:
1187 		tbd = DP_TEST_BIT_DEPTH_10;
1188 		break;
1189 	default:
1190 		tbd = DP_TEST_BIT_DEPTH_UNKNOWN;
1191 		break;
1192 	}
1193 
1194 	if (tbd != DP_TEST_BIT_DEPTH_UNKNOWN)
1195 		tbd = (tbd >> DP_TEST_BIT_DEPTH_SHIFT);
1196 
1197 	return tbd;
1198 }
1199 
dp_link_get(struct device * dev,struct drm_dp_aux * aux)1200 struct dp_link *dp_link_get(struct device *dev, struct drm_dp_aux *aux)
1201 {
1202 	struct dp_link_private *link;
1203 	struct dp_link *dp_link;
1204 
1205 	if (!dev || !aux) {
1206 		DRM_ERROR("invalid input\n");
1207 		return ERR_PTR(-EINVAL);
1208 	}
1209 
1210 	link = devm_kzalloc(dev, sizeof(*link), GFP_KERNEL);
1211 	if (!link)
1212 		return ERR_PTR(-ENOMEM);
1213 
1214 	link->dev   = dev;
1215 	link->aux   = aux;
1216 
1217 	mutex_init(&link->psm_mutex);
1218 	dp_link = &link->dp_link;
1219 
1220 	return dp_link;
1221 }
1222