xref: /openbmc/u-boot/drivers/video/tegra124/dp.c (revision 8ee59472)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2011-2013, NVIDIA Corporation.
4  * Copyright 2014 Google Inc.
5  */
6 
7 #include <common.h>
8 #include <display.h>
9 #include <dm.h>
10 #include <div64.h>
11 #include <errno.h>
12 #include <video_bridge.h>
13 #include <asm/io.h>
14 #include <asm/arch-tegra/dc.h>
15 #include "display.h"
16 #include "edid.h"
17 #include "sor.h"
18 #include "displayport.h"
19 
20 #define DO_FAST_LINK_TRAINING		1
21 
22 struct tegra_dp_plat {
23 	ulong base;
24 };
25 
26 /**
27  * struct tegra_dp_priv - private displayport driver info
28  *
29  * @dc_dev:	Display controller device that is sending the video feed
30  */
31 struct tegra_dp_priv {
32 	struct udevice *sor;
33 	struct udevice *dc_dev;
34 	struct dpaux_ctlr *regs;
35 	u8 revision;
36 	int enabled;
37 };
38 
39 struct tegra_dp_priv dp_data;
40 
41 static inline u32 tegra_dpaux_readl(struct tegra_dp_priv *dp, u32 reg)
42 {
43 	return readl((u32 *)dp->regs + reg);
44 }
45 
46 static inline void tegra_dpaux_writel(struct tegra_dp_priv *dp, u32 reg,
47 				      u32 val)
48 {
49 	writel(val, (u32 *)dp->regs + reg);
50 }
51 
52 static inline u32 tegra_dc_dpaux_poll_register(struct tegra_dp_priv *dp,
53 					   u32 reg, u32 mask, u32 exp_val,
54 					   u32 poll_interval_us,
55 					   u32 timeout_us)
56 {
57 	u32 reg_val = 0;
58 	u32 temp = timeout_us;
59 
60 	do {
61 		udelay(poll_interval_us);
62 		reg_val = tegra_dpaux_readl(dp, reg);
63 		if (timeout_us > poll_interval_us)
64 			timeout_us -= poll_interval_us;
65 		else
66 			break;
67 	} while ((reg_val & mask) != exp_val);
68 
69 	if ((reg_val & mask) == exp_val)
70 		return 0;	/* success */
71 	debug("dpaux_poll_register 0x%x: timeout: (reg_val)0x%08x & (mask)0x%08x != (exp_val)0x%08x\n",
72 	      reg, reg_val, mask, exp_val);
73 	return temp;
74 }
75 
76 static inline int tegra_dpaux_wait_transaction(struct tegra_dp_priv *dp)
77 {
78 	/* According to DP spec, each aux transaction needs to finish
79 	   within 40ms. */
80 	if (tegra_dc_dpaux_poll_register(dp, DPAUX_DP_AUXCTL,
81 					 DPAUX_DP_AUXCTL_TRANSACTREQ_MASK,
82 					 DPAUX_DP_AUXCTL_TRANSACTREQ_DONE,
83 					 100, DP_AUX_TIMEOUT_MS * 1000) != 0) {
84 		debug("dp: DPAUX transaction timeout\n");
85 		return -1;
86 	}
87 	return 0;
88 }
89 
90 static int tegra_dc_dpaux_write_chunk(struct tegra_dp_priv *dp, u32 cmd,
91 					  u32 addr, u8 *data, u32 *size,
92 					  u32 *aux_stat)
93 {
94 	int i;
95 	u32 reg_val;
96 	u32 timeout_retries = DP_AUX_TIMEOUT_MAX_TRIES;
97 	u32 defer_retries = DP_AUX_DEFER_MAX_TRIES;
98 	u32 temp_data;
99 
100 	if (*size > DP_AUX_MAX_BYTES)
101 		return -1;	/* only write one chunk of data */
102 
103 	/* Make sure the command is write command */
104 	switch (cmd) {
105 	case DPAUX_DP_AUXCTL_CMD_I2CWR:
106 	case DPAUX_DP_AUXCTL_CMD_MOTWR:
107 	case DPAUX_DP_AUXCTL_CMD_AUXWR:
108 		break;
109 	default:
110 		debug("dp: aux write cmd 0x%x is invalid\n", cmd);
111 		return -EINVAL;
112 	}
113 
114 	tegra_dpaux_writel(dp, DPAUX_DP_AUXADDR, addr);
115 	for (i = 0; i < DP_AUX_MAX_BYTES / 4; ++i) {
116 		memcpy(&temp_data, data, 4);
117 		tegra_dpaux_writel(dp, DPAUX_DP_AUXDATA_WRITE_W(i), temp_data);
118 		data += 4;
119 	}
120 
121 	reg_val = tegra_dpaux_readl(dp, DPAUX_DP_AUXCTL);
122 	reg_val &= ~DPAUX_DP_AUXCTL_CMD_MASK;
123 	reg_val |= cmd;
124 	reg_val &= ~DPAUX_DP_AUXCTL_CMDLEN_FIELD;
125 	reg_val |= ((*size - 1) << DPAUX_DP_AUXCTL_CMDLEN_SHIFT);
126 
127 	while ((timeout_retries > 0) && (defer_retries > 0)) {
128 		if ((timeout_retries != DP_AUX_TIMEOUT_MAX_TRIES) ||
129 		    (defer_retries != DP_AUX_DEFER_MAX_TRIES))
130 			udelay(1);
131 
132 		reg_val |= DPAUX_DP_AUXCTL_TRANSACTREQ_PENDING;
133 		tegra_dpaux_writel(dp, DPAUX_DP_AUXCTL, reg_val);
134 
135 		if (tegra_dpaux_wait_transaction(dp))
136 			debug("dp: aux write transaction timeout\n");
137 
138 		*aux_stat = tegra_dpaux_readl(dp, DPAUX_DP_AUXSTAT);
139 
140 		if ((*aux_stat & DPAUX_DP_AUXSTAT_TIMEOUT_ERROR_PENDING) ||
141 		    (*aux_stat & DPAUX_DP_AUXSTAT_RX_ERROR_PENDING) ||
142 		    (*aux_stat & DPAUX_DP_AUXSTAT_SINKSTAT_ERROR_PENDING) ||
143 		    (*aux_stat & DPAUX_DP_AUXSTAT_NO_STOP_ERROR_PENDING)) {
144 			if (timeout_retries-- > 0) {
145 				debug("dp: aux write retry (0x%x) -- %d\n",
146 				      *aux_stat, timeout_retries);
147 				/* clear the error bits */
148 				tegra_dpaux_writel(dp, DPAUX_DP_AUXSTAT,
149 						   *aux_stat);
150 				continue;
151 			} else {
152 				debug("dp: aux write got error (0x%x)\n",
153 				      *aux_stat);
154 				return -ETIMEDOUT;
155 			}
156 		}
157 
158 		if ((*aux_stat & DPAUX_DP_AUXSTAT_REPLYTYPE_I2CDEFER) ||
159 		    (*aux_stat & DPAUX_DP_AUXSTAT_REPLYTYPE_DEFER)) {
160 			if (defer_retries-- > 0) {
161 				debug("dp: aux write defer (0x%x) -- %d\n",
162 				      *aux_stat, defer_retries);
163 				/* clear the error bits */
164 				tegra_dpaux_writel(dp, DPAUX_DP_AUXSTAT,
165 						   *aux_stat);
166 				continue;
167 			} else {
168 				debug("dp: aux write defer exceeds max retries (0x%x)\n",
169 				      *aux_stat);
170 				return -ETIMEDOUT;
171 			}
172 		}
173 
174 		if ((*aux_stat & DPAUX_DP_AUXSTAT_REPLYTYPE_MASK) ==
175 			DPAUX_DP_AUXSTAT_REPLYTYPE_ACK) {
176 			*size = ((*aux_stat) & DPAUX_DP_AUXSTAT_REPLY_M_MASK);
177 			return 0;
178 		} else {
179 			debug("dp: aux write failed (0x%x)\n", *aux_stat);
180 			return -EIO;
181 		}
182 	}
183 	/* Should never come to here */
184 	return -EIO;
185 }
186 
187 static int tegra_dc_dpaux_read_chunk(struct tegra_dp_priv *dp, u32 cmd,
188 					 u32 addr, u8 *data, u32 *size,
189 					 u32 *aux_stat)
190 {
191 	u32 reg_val;
192 	u32 timeout_retries = DP_AUX_TIMEOUT_MAX_TRIES;
193 	u32 defer_retries = DP_AUX_DEFER_MAX_TRIES;
194 
195 	if (*size > DP_AUX_MAX_BYTES) {
196 		debug("only read one chunk\n");
197 		return -EIO;	/* only read one chunk */
198 	}
199 
200 	/* Check to make sure the command is read command */
201 	switch (cmd) {
202 	case DPAUX_DP_AUXCTL_CMD_I2CRD:
203 	case DPAUX_DP_AUXCTL_CMD_I2CREQWSTAT:
204 	case DPAUX_DP_AUXCTL_CMD_MOTRD:
205 	case DPAUX_DP_AUXCTL_CMD_AUXRD:
206 		break;
207 	default:
208 		debug("dp: aux read cmd 0x%x is invalid\n", cmd);
209 		return -EIO;
210 	}
211 
212 	*aux_stat = tegra_dpaux_readl(dp, DPAUX_DP_AUXSTAT);
213 	if (!(*aux_stat & DPAUX_DP_AUXSTAT_HPD_STATUS_PLUGGED)) {
214 		debug("dp: HPD is not detected\n");
215 		return -EIO;
216 	}
217 
218 	tegra_dpaux_writel(dp, DPAUX_DP_AUXADDR, addr);
219 
220 	reg_val = tegra_dpaux_readl(dp, DPAUX_DP_AUXCTL);
221 	reg_val &= ~DPAUX_DP_AUXCTL_CMD_MASK;
222 	reg_val |= cmd;
223 	reg_val &= ~DPAUX_DP_AUXCTL_CMDLEN_FIELD;
224 	reg_val |= ((*size - 1) << DPAUX_DP_AUXCTL_CMDLEN_SHIFT);
225 	while ((timeout_retries > 0) && (defer_retries > 0)) {
226 		if ((timeout_retries != DP_AUX_TIMEOUT_MAX_TRIES) ||
227 		    (defer_retries != DP_AUX_DEFER_MAX_TRIES))
228 			udelay(DP_DPCP_RETRY_SLEEP_NS * 2);
229 
230 		reg_val |= DPAUX_DP_AUXCTL_TRANSACTREQ_PENDING;
231 		tegra_dpaux_writel(dp, DPAUX_DP_AUXCTL, reg_val);
232 
233 		if (tegra_dpaux_wait_transaction(dp))
234 			debug("dp: aux read transaction timeout\n");
235 
236 		*aux_stat = tegra_dpaux_readl(dp, DPAUX_DP_AUXSTAT);
237 
238 		if ((*aux_stat & DPAUX_DP_AUXSTAT_TIMEOUT_ERROR_PENDING) ||
239 		    (*aux_stat & DPAUX_DP_AUXSTAT_RX_ERROR_PENDING) ||
240 		    (*aux_stat & DPAUX_DP_AUXSTAT_SINKSTAT_ERROR_PENDING) ||
241 		    (*aux_stat & DPAUX_DP_AUXSTAT_NO_STOP_ERROR_PENDING)) {
242 			if (timeout_retries-- > 0) {
243 				debug("dp: aux read retry (0x%x) -- %d\n",
244 				      *aux_stat, timeout_retries);
245 				/* clear the error bits */
246 				tegra_dpaux_writel(dp, DPAUX_DP_AUXSTAT,
247 						   *aux_stat);
248 				continue;	/* retry */
249 			} else {
250 				debug("dp: aux read got error (0x%x)\n",
251 				      *aux_stat);
252 				return -ETIMEDOUT;
253 			}
254 		}
255 
256 		if ((*aux_stat & DPAUX_DP_AUXSTAT_REPLYTYPE_I2CDEFER) ||
257 		    (*aux_stat & DPAUX_DP_AUXSTAT_REPLYTYPE_DEFER)) {
258 			if (defer_retries-- > 0) {
259 				debug("dp: aux read defer (0x%x) -- %d\n",
260 				      *aux_stat, defer_retries);
261 				/* clear the error bits */
262 				tegra_dpaux_writel(dp, DPAUX_DP_AUXSTAT,
263 						   *aux_stat);
264 				continue;
265 			} else {
266 				debug("dp: aux read defer exceeds max retries (0x%x)\n",
267 				      *aux_stat);
268 				return -ETIMEDOUT;
269 			}
270 		}
271 
272 		if ((*aux_stat & DPAUX_DP_AUXSTAT_REPLYTYPE_MASK) ==
273 			DPAUX_DP_AUXSTAT_REPLYTYPE_ACK) {
274 			int i;
275 			u32 temp_data[4];
276 
277 			for (i = 0; i < DP_AUX_MAX_BYTES / 4; ++i)
278 				temp_data[i] = tegra_dpaux_readl(dp,
279 						DPAUX_DP_AUXDATA_READ_W(i));
280 
281 			*size = ((*aux_stat) & DPAUX_DP_AUXSTAT_REPLY_M_MASK);
282 			memcpy(data, temp_data, *size);
283 
284 			return 0;
285 		} else {
286 			debug("dp: aux read failed (0x%x\n", *aux_stat);
287 			return -EIO;
288 		}
289 	}
290 	/* Should never come to here */
291 	debug("%s: can't\n", __func__);
292 
293 	return -EIO;
294 }
295 
296 static int tegra_dc_dpaux_read(struct tegra_dp_priv *dp, u32 cmd, u32 addr,
297 			u8 *data, u32 *size, u32 *aux_stat)
298 {
299 	u32 finished = 0;
300 	u32 cur_size;
301 	int ret = 0;
302 
303 	do {
304 		cur_size = *size - finished;
305 		if (cur_size > DP_AUX_MAX_BYTES)
306 			cur_size = DP_AUX_MAX_BYTES;
307 
308 		ret = tegra_dc_dpaux_read_chunk(dp, cmd, addr,
309 						data, &cur_size, aux_stat);
310 		if (ret)
311 			break;
312 
313 		/* cur_size should be the real size returned */
314 		addr += cur_size;
315 		data += cur_size;
316 		finished += cur_size;
317 
318 	} while (*size > finished);
319 	*size = finished;
320 
321 	return ret;
322 }
323 
324 static int tegra_dc_dp_dpcd_read(struct tegra_dp_priv *dp, u32 cmd,
325 				 u8 *data_ptr)
326 {
327 	u32 size = 1;
328 	u32 status = 0;
329 	int ret;
330 
331 	ret = tegra_dc_dpaux_read_chunk(dp, DPAUX_DP_AUXCTL_CMD_AUXRD,
332 					cmd, data_ptr, &size, &status);
333 	if (ret) {
334 		debug("dp: Failed to read DPCD data. CMD 0x%x, Status 0x%x\n",
335 		      cmd, status);
336 	}
337 
338 	return ret;
339 }
340 
341 static int tegra_dc_dp_dpcd_write(struct tegra_dp_priv *dp, u32 cmd,
342 				u8 data)
343 {
344 	u32 size = 1;
345 	u32 status = 0;
346 	int ret;
347 
348 	ret = tegra_dc_dpaux_write_chunk(dp, DPAUX_DP_AUXCTL_CMD_AUXWR,
349 					cmd, &data, &size, &status);
350 	if (ret) {
351 		debug("dp: Failed to write DPCD data. CMD 0x%x, Status 0x%x\n",
352 		      cmd, status);
353 	}
354 
355 	return ret;
356 }
357 
358 static int tegra_dc_i2c_aux_read(struct tegra_dp_priv *dp, u32 i2c_addr,
359 				 u8 addr, u8 *data, u32 size, u32 *aux_stat)
360 {
361 	u32 finished = 0;
362 	int ret = 0;
363 
364 	do {
365 		u32 cur_size = min((u32)DP_AUX_MAX_BYTES, size - finished);
366 
367 		u32 len = 1;
368 		ret = tegra_dc_dpaux_write_chunk(
369 				dp, DPAUX_DP_AUXCTL_CMD_MOTWR, i2c_addr,
370 				&addr, &len, aux_stat);
371 		if (ret) {
372 			debug("%s: error sending address to read.\n",
373 			      __func__);
374 			return ret;
375 		}
376 
377 		ret = tegra_dc_dpaux_read_chunk(
378 				dp, DPAUX_DP_AUXCTL_CMD_I2CRD, i2c_addr,
379 				data, &cur_size, aux_stat);
380 		if (ret) {
381 			debug("%s: error reading data.\n", __func__);
382 			return ret;
383 		}
384 
385 		/* cur_size should be the real size returned */
386 		addr += cur_size;
387 		data += cur_size;
388 		finished += cur_size;
389 	} while (size > finished);
390 
391 	return finished;
392 }
393 
394 static void tegra_dc_dpaux_enable(struct tegra_dp_priv *dp)
395 {
396 	/* clear interrupt */
397 	tegra_dpaux_writel(dp, DPAUX_INTR_AUX, 0xffffffff);
398 	/* do not enable interrupt for now. Enable them when Isr in place */
399 	tegra_dpaux_writel(dp, DPAUX_INTR_EN_AUX, 0x0);
400 
401 	tegra_dpaux_writel(dp, DPAUX_HYBRID_PADCTL,
402 			   DPAUX_HYBRID_PADCTL_AUX_DRVZ_OHM_50 |
403 			   DPAUX_HYBRID_PADCTL_AUX_CMH_V0_70 |
404 			   0x18 << DPAUX_HYBRID_PADCTL_AUX_DRVI_SHIFT |
405 			   DPAUX_HYBRID_PADCTL_AUX_INPUT_RCV_ENABLE);
406 
407 	tegra_dpaux_writel(dp, DPAUX_HYBRID_SPARE,
408 			   DPAUX_HYBRID_SPARE_PAD_PWR_POWERUP);
409 }
410 
411 #ifdef DEBUG
412 static void tegra_dc_dp_dump_link_cfg(struct tegra_dp_priv *dp,
413 	const struct tegra_dp_link_config *link_cfg)
414 {
415 	debug("DP config: cfg_name               cfg_value\n");
416 	debug("           Lane Count             %d\n",
417 	      link_cfg->max_lane_count);
418 	debug("           SupportEnhancedFraming %s\n",
419 	      link_cfg->support_enhanced_framing ? "Y" : "N");
420 	debug("           Bandwidth              %d\n",
421 	      link_cfg->max_link_bw);
422 	debug("           bpp                    %d\n",
423 	      link_cfg->bits_per_pixel);
424 	debug("           EnhancedFraming        %s\n",
425 	      link_cfg->enhanced_framing ? "Y" : "N");
426 	debug("           Scramble_enabled       %s\n",
427 	      link_cfg->scramble_ena ? "Y" : "N");
428 	debug("           LinkBW                 %d\n",
429 	      link_cfg->link_bw);
430 	debug("           lane_count             %d\n",
431 	      link_cfg->lane_count);
432 	debug("           activespolarity        %d\n",
433 	      link_cfg->activepolarity);
434 	debug("           active_count           %d\n",
435 	      link_cfg->active_count);
436 	debug("           tu_size                %d\n",
437 	      link_cfg->tu_size);
438 	debug("           active_frac            %d\n",
439 	      link_cfg->active_frac);
440 	debug("           watermark              %d\n",
441 	      link_cfg->watermark);
442 	debug("           hblank_sym             %d\n",
443 	      link_cfg->hblank_sym);
444 	debug("           vblank_sym             %d\n",
445 	      link_cfg->vblank_sym);
446 }
447 #endif
448 
449 static int _tegra_dp_lower_link_config(struct tegra_dp_priv *dp,
450 				       struct tegra_dp_link_config *cfg)
451 {
452 	switch (cfg->link_bw) {
453 	case SOR_LINK_SPEED_G1_62:
454 		if (cfg->max_link_bw > SOR_LINK_SPEED_G1_62)
455 			cfg->link_bw = SOR_LINK_SPEED_G2_7;
456 		cfg->lane_count /= 2;
457 		break;
458 	case SOR_LINK_SPEED_G2_7:
459 		cfg->link_bw = SOR_LINK_SPEED_G1_62;
460 		break;
461 	case SOR_LINK_SPEED_G5_4:
462 		if (cfg->lane_count == 1) {
463 			cfg->link_bw = SOR_LINK_SPEED_G2_7;
464 			cfg->lane_count = cfg->max_lane_count;
465 		} else {
466 			cfg->lane_count /= 2;
467 		}
468 		break;
469 	default:
470 		debug("dp: Error link rate %d\n", cfg->link_bw);
471 		return -ENOLINK;
472 	}
473 
474 	return (cfg->lane_count > 0) ? 0 : -ENOLINK;
475 }
476 
477 /*
478  * Calcuate if given cfg can meet the mode request.
479  * Return 0 if mode is possible, -1 otherwise
480  */
481 static int tegra_dc_dp_calc_config(struct tegra_dp_priv *dp,
482 				   const struct display_timing *timing,
483 				   struct tegra_dp_link_config *link_cfg)
484 {
485 	const u32	link_rate = 27 * link_cfg->link_bw * 1000 * 1000;
486 	const u64	f	  = 100000;	/* precision factor */
487 	u32	num_linkclk_line; /* Number of link clocks per line */
488 	u64	ratio_f; /* Ratio of incoming to outgoing data rate */
489 	u64	frac_f;
490 	u64	activesym_f;	/* Activesym per TU */
491 	u64	activecount_f;
492 	u32	activecount;
493 	u32	activepolarity;
494 	u64	approx_value_f;
495 	u32	activefrac		  = 0;
496 	u64	accumulated_error_f	  = 0;
497 	u32	lowest_neg_activecount	  = 0;
498 	u32	lowest_neg_activepolarity = 0;
499 	u32	lowest_neg_tusize	  = 64;
500 	u32	num_symbols_per_line;
501 	u64	lowest_neg_activefrac	  = 0;
502 	u64	lowest_neg_error_f	  = 64 * f;
503 	u64	watermark_f;
504 	int	i;
505 	int	neg;
506 
507 	if (!link_rate || !link_cfg->lane_count || !timing->pixelclock.typ ||
508 	    !link_cfg->bits_per_pixel)
509 		return -1;
510 
511 	if ((u64)timing->pixelclock.typ * link_cfg->bits_per_pixel >=
512 		(u64)link_rate * 8 * link_cfg->lane_count)
513 		return -1;
514 
515 	num_linkclk_line = (u32)(lldiv(link_rate * timing->hactive.typ,
516 				       timing->pixelclock.typ));
517 
518 	ratio_f = (u64)timing->pixelclock.typ * link_cfg->bits_per_pixel * f;
519 	ratio_f /= 8;
520 	do_div(ratio_f, link_rate * link_cfg->lane_count);
521 
522 	for (i = 64; i >= 32; --i) {
523 		activesym_f	= ratio_f * i;
524 		activecount_f	= lldiv(activesym_f, (u32)f) * f;
525 		frac_f		= activesym_f - activecount_f;
526 		activecount	= (u32)(lldiv(activecount_f, (u32)f));
527 
528 		if (frac_f < (lldiv(f, 2))) /* fraction < 0.5 */
529 			activepolarity = 0;
530 		else {
531 			activepolarity = 1;
532 			frac_f = f - frac_f;
533 		}
534 
535 		if (frac_f != 0) {
536 			/* warning: frac_f should be 64-bit */
537 			frac_f = lldiv(f * f, frac_f); /* 1 / fraction */
538 			if (frac_f > (15 * f))
539 				activefrac = activepolarity ? 1 : 15;
540 			else
541 				activefrac = activepolarity ?
542 					(u32)lldiv(frac_f, (u32)f) + 1 :
543 					(u32)lldiv(frac_f, (u32)f);
544 		}
545 
546 		if (activefrac == 1)
547 			activepolarity = 0;
548 
549 		if (activepolarity == 1)
550 			approx_value_f = activefrac ? lldiv(
551 				(activecount_f + (activefrac * f - f) * f),
552 				(activefrac * f)) :
553 				activecount_f + f;
554 		else
555 			approx_value_f = activefrac ?
556 				activecount_f + lldiv(f, activefrac) :
557 				activecount_f;
558 
559 		if (activesym_f < approx_value_f) {
560 			accumulated_error_f = num_linkclk_line *
561 				lldiv(approx_value_f - activesym_f, i);
562 			neg = 1;
563 		} else {
564 			accumulated_error_f = num_linkclk_line *
565 				lldiv(activesym_f - approx_value_f, i);
566 			neg = 0;
567 		}
568 
569 		if ((neg && (lowest_neg_error_f > accumulated_error_f)) ||
570 		    (accumulated_error_f == 0)) {
571 			lowest_neg_error_f = accumulated_error_f;
572 			lowest_neg_tusize = i;
573 			lowest_neg_activecount = activecount;
574 			lowest_neg_activepolarity = activepolarity;
575 			lowest_neg_activefrac = activefrac;
576 
577 			if (accumulated_error_f == 0)
578 				break;
579 		}
580 	}
581 
582 	if (lowest_neg_activefrac == 0) {
583 		link_cfg->activepolarity = 0;
584 		link_cfg->active_count   = lowest_neg_activepolarity ?
585 			lowest_neg_activecount : lowest_neg_activecount - 1;
586 		link_cfg->tu_size	      = lowest_neg_tusize;
587 		link_cfg->active_frac    = 1;
588 	} else {
589 		link_cfg->activepolarity = lowest_neg_activepolarity;
590 		link_cfg->active_count   = (u32)lowest_neg_activecount;
591 		link_cfg->tu_size	      = lowest_neg_tusize;
592 		link_cfg->active_frac    = (u32)lowest_neg_activefrac;
593 	}
594 
595 	watermark_f = lldiv(ratio_f * link_cfg->tu_size * (f - ratio_f), f);
596 	link_cfg->watermark = (u32)(lldiv(watermark_f + lowest_neg_error_f,
597 		f)) + link_cfg->bits_per_pixel / 4 - 1;
598 	num_symbols_per_line = (timing->hactive.typ *
599 				link_cfg->bits_per_pixel) /
600 			       (8 * link_cfg->lane_count);
601 
602 	if (link_cfg->watermark > 30) {
603 		debug("dp: sor setting: unable to get a good tusize, force watermark to 30\n");
604 		link_cfg->watermark = 30;
605 		return -1;
606 	} else if (link_cfg->watermark > num_symbols_per_line) {
607 		debug("dp: sor setting: force watermark to the number of symbols in the line\n");
608 		link_cfg->watermark = num_symbols_per_line;
609 		return -1;
610 	}
611 
612 	/*
613 	 * Refer to dev_disp.ref for more information.
614 	 * # symbols/hblank = ((SetRasterBlankEnd.X + SetRasterSize.Width -
615 	 *                      SetRasterBlankStart.X - 7) * link_clk / pclk)
616 	 *                      - 3 * enhanced_framing - Y
617 	 * where Y = (# lanes == 4) 3 : (# lanes == 2) ? 6 : 12
618 	 */
619 	link_cfg->hblank_sym = (int)lldiv(((uint64_t)timing->hback_porch.typ +
620 			timing->hfront_porch.typ + timing->hsync_len.typ - 7) *
621 			link_rate, timing->pixelclock.typ) -
622 			3 * link_cfg->enhanced_framing -
623 			(12 / link_cfg->lane_count);
624 
625 	if (link_cfg->hblank_sym < 0)
626 		link_cfg->hblank_sym = 0;
627 
628 
629 	/*
630 	 * Refer to dev_disp.ref for more information.
631 	 * # symbols/vblank = ((SetRasterBlankStart.X -
632 	 *                      SetRasterBlankEen.X - 25) * link_clk / pclk)
633 	 *                      - Y - 1;
634 	 * where Y = (# lanes == 4) 12 : (# lanes == 2) ? 21 : 39
635 	 */
636 	link_cfg->vblank_sym = (int)lldiv(((uint64_t)timing->hactive.typ - 25)
637 			* link_rate, timing->pixelclock.typ) - (36 /
638 			link_cfg->lane_count) - 4;
639 
640 	if (link_cfg->vblank_sym < 0)
641 		link_cfg->vblank_sym = 0;
642 
643 	link_cfg->is_valid = 1;
644 #ifdef DEBUG
645 	tegra_dc_dp_dump_link_cfg(dp, link_cfg);
646 #endif
647 
648 	return 0;
649 }
650 
651 static int tegra_dc_dp_init_max_link_cfg(
652 			const struct display_timing *timing,
653 			struct tegra_dp_priv *dp,
654 			struct tegra_dp_link_config *link_cfg)
655 {
656 	const int drive_current = 0x40404040;
657 	const int preemphasis = 0x0f0f0f0f;
658 	const int postcursor = 0;
659 	u8 dpcd_data;
660 	int ret;
661 
662 	ret = tegra_dc_dp_dpcd_read(dp, DP_MAX_LANE_COUNT, &dpcd_data);
663 	if (ret)
664 		return ret;
665 	link_cfg->max_lane_count = dpcd_data & DP_MAX_LANE_COUNT_MASK;
666 	link_cfg->tps3_supported = (dpcd_data &
667 			DP_MAX_LANE_COUNT_TPS3_SUPPORTED_YES) ? 1 : 0;
668 
669 	link_cfg->support_enhanced_framing =
670 		(dpcd_data & DP_MAX_LANE_COUNT_ENHANCED_FRAMING_YES) ?
671 		1 : 0;
672 
673 	ret = tegra_dc_dp_dpcd_read(dp, DP_MAX_DOWNSPREAD, &dpcd_data);
674 	if (ret)
675 		return ret;
676 	link_cfg->downspread = (dpcd_data & DP_MAX_DOWNSPREAD_VAL_0_5_PCT) ?
677 				1 : 0;
678 
679 	ret = tegra_dc_dp_dpcd_read(dp, NV_DPCD_TRAINING_AUX_RD_INTERVAL,
680 				    &link_cfg->aux_rd_interval);
681 	if (ret)
682 		return ret;
683 	ret = tegra_dc_dp_dpcd_read(dp, DP_MAX_LINK_RATE,
684 				    &link_cfg->max_link_bw);
685 	if (ret)
686 		return ret;
687 
688 	/*
689 	 * Set to a high value for link training and attach.
690 	 * Will be re-programmed when dp is enabled.
691 	 */
692 	link_cfg->drive_current = drive_current;
693 	link_cfg->preemphasis = preemphasis;
694 	link_cfg->postcursor = postcursor;
695 
696 	ret = tegra_dc_dp_dpcd_read(dp, DP_EDP_CONFIGURATION_CAP, &dpcd_data);
697 	if (ret)
698 		return ret;
699 
700 	link_cfg->alt_scramber_reset_cap =
701 		(dpcd_data & DP_EDP_CONFIGURATION_CAP_ASC_RESET_YES) ?
702 		1 : 0;
703 	link_cfg->only_enhanced_framing =
704 		(dpcd_data & DP_EDP_CONFIGURATION_CAP_FRAMING_CHANGE_YES) ?
705 		1 : 0;
706 
707 	link_cfg->lane_count = link_cfg->max_lane_count;
708 	link_cfg->link_bw = link_cfg->max_link_bw;
709 	link_cfg->enhanced_framing = link_cfg->support_enhanced_framing;
710 	link_cfg->frame_in_ms = (1000 / 60) + 1;
711 
712 	tegra_dc_dp_calc_config(dp, timing, link_cfg);
713 	return 0;
714 }
715 
716 static int tegra_dc_dp_set_assr(struct tegra_dp_priv *priv,
717 				struct udevice *sor, int ena)
718 {
719 	int ret;
720 
721 	u8 dpcd_data = ena ?
722 		DP_MAIN_LINK_CHANNEL_CODING_SET_ASC_RESET_ENABLE :
723 		DP_MAIN_LINK_CHANNEL_CODING_SET_ASC_RESET_DISABLE;
724 
725 	ret = tegra_dc_dp_dpcd_write(priv, DP_EDP_CONFIGURATION_SET,
726 				     dpcd_data);
727 	if (ret)
728 		return ret;
729 
730 	/* Also reset the scrambler to 0xfffe */
731 	tegra_dc_sor_set_internal_panel(sor, ena);
732 	return 0;
733 }
734 
735 static int tegra_dp_set_link_bandwidth(struct tegra_dp_priv *dp,
736 				       struct udevice *sor,
737 				       u8 link_bw)
738 {
739 	tegra_dc_sor_set_link_bandwidth(sor, link_bw);
740 
741 	/* Sink side */
742 	return tegra_dc_dp_dpcd_write(dp, DP_LINK_BW_SET, link_bw);
743 }
744 
745 static int tegra_dp_set_lane_count(struct tegra_dp_priv *dp,
746 		const struct tegra_dp_link_config *link_cfg,
747 		struct udevice *sor)
748 {
749 	u8	dpcd_data;
750 	int	ret;
751 
752 	/* check if panel support enhanched_framing */
753 	dpcd_data = link_cfg->lane_count;
754 	if (link_cfg->enhanced_framing)
755 		dpcd_data |= DP_LANE_COUNT_SET_ENHANCEDFRAMING_T;
756 	ret = tegra_dc_dp_dpcd_write(dp, DP_LANE_COUNT_SET, dpcd_data);
757 	if (ret)
758 		return ret;
759 
760 	tegra_dc_sor_set_lane_count(sor, link_cfg->lane_count);
761 
762 	/* Also power down lanes that will not be used */
763 	return 0;
764 }
765 
766 static int tegra_dc_dp_link_trained(struct tegra_dp_priv *dp,
767 				    const struct tegra_dp_link_config *cfg)
768 {
769 	u32 lane;
770 	u8 mask;
771 	u8 data;
772 	int ret;
773 
774 	for (lane = 0; lane < cfg->lane_count; ++lane) {
775 		ret = tegra_dc_dp_dpcd_read(dp, (lane / 2) ?
776 				DP_LANE2_3_STATUS : DP_LANE0_1_STATUS,
777 				&data);
778 		if (ret)
779 			return ret;
780 		mask = (lane & 1) ?
781 			NV_DPCD_STATUS_LANEXPLUS1_CR_DONE_YES |
782 			NV_DPCD_STATUS_LANEXPLUS1_CHN_EQ_DONE_YES |
783 			NV_DPCD_STATUS_LANEXPLUS1_SYMBOL_LOCKED_YES :
784 			DP_LANE_CR_DONE |
785 			DP_LANE_CHANNEL_EQ_DONE |
786 			DP_LANE_SYMBOL_LOCKED;
787 		if ((data & mask) != mask)
788 			return -1;
789 	}
790 	return 0;
791 }
792 
793 static int tegra_dp_channel_eq_status(struct tegra_dp_priv *dp,
794 				      const struct tegra_dp_link_config *cfg)
795 {
796 	u32 cnt;
797 	u32 n_lanes = cfg->lane_count;
798 	u8 data;
799 	u8 ce_done = 1;
800 	int ret;
801 
802 	for (cnt = 0; cnt < n_lanes / 2; cnt++) {
803 		ret = tegra_dc_dp_dpcd_read(dp, DP_LANE0_1_STATUS + cnt, &data);
804 		if (ret)
805 			return ret;
806 
807 		if (n_lanes == 1) {
808 			ce_done = (data & (0x1 <<
809 			NV_DPCD_STATUS_LANEX_CHN_EQ_DONE_SHIFT)) &&
810 			(data & (0x1 <<
811 			NV_DPCD_STATUS_LANEX_SYMBOL_LOCKED_SHFIT));
812 			break;
813 		} else if (!(data & (0x1 <<
814 				NV_DPCD_STATUS_LANEX_CHN_EQ_DONE_SHIFT)) ||
815 			   !(data & (0x1 <<
816 				NV_DPCD_STATUS_LANEX_SYMBOL_LOCKED_SHFIT)) ||
817 			   !(data & (0x1 <<
818 				NV_DPCD_STATUS_LANEXPLUS1_CHN_EQ_DONE_SHIFT)) ||
819 			   !(data & (0x1 <<
820 				NV_DPCD_STATUS_LANEXPLUS1_SYMBOL_LOCKED_SHIFT)))
821 			return -EIO;
822 	}
823 
824 	if (ce_done) {
825 		ret = tegra_dc_dp_dpcd_read(dp,
826 					    DP_LANE_ALIGN_STATUS_UPDATED,
827 					    &data);
828 		if (ret)
829 			return ret;
830 		if (!(data & NV_DPCD_LANE_ALIGN_STATUS_UPDATED_DONE_YES))
831 			ce_done = 0;
832 	}
833 
834 	return ce_done ? 0 : -EIO;
835 }
836 
837 static int tegra_dp_clock_recovery_status(struct tegra_dp_priv *dp,
838 					 const struct tegra_dp_link_config *cfg)
839 {
840 	u32 cnt;
841 	u32 n_lanes = cfg->lane_count;
842 	u8 data_ptr;
843 	int ret;
844 
845 	for (cnt = 0; cnt < n_lanes / 2; cnt++) {
846 		ret = tegra_dc_dp_dpcd_read(dp, (DP_LANE0_1_STATUS + cnt),
847 					    &data_ptr);
848 		if (ret)
849 			return ret;
850 
851 		if (n_lanes == 1)
852 			return (data_ptr & NV_DPCD_STATUS_LANEX_CR_DONE_YES) ?
853 				1 : 0;
854 		else if (!(data_ptr & NV_DPCD_STATUS_LANEX_CR_DONE_YES) ||
855 			 !(data_ptr & (NV_DPCD_STATUS_LANEXPLUS1_CR_DONE_YES)))
856 			return 0;
857 	}
858 
859 	return 1;
860 }
861 
862 static int tegra_dp_lt_adjust(struct tegra_dp_priv *dp, u32 pe[4], u32 vs[4],
863 			      u32 pc[4], u8 pc_supported,
864 			      const struct tegra_dp_link_config *cfg)
865 {
866 	size_t cnt;
867 	u8 data_ptr;
868 	u32 n_lanes = cfg->lane_count;
869 	int ret;
870 
871 	for (cnt = 0; cnt < n_lanes / 2; cnt++) {
872 		ret = tegra_dc_dp_dpcd_read(dp, DP_ADJUST_REQUEST_LANE0_1 + cnt,
873 					    &data_ptr);
874 		if (ret)
875 			return ret;
876 		pe[2 * cnt] = (data_ptr & NV_DPCD_ADJUST_REQ_LANEX_PE_MASK) >>
877 					NV_DPCD_ADJUST_REQ_LANEX_PE_SHIFT;
878 		vs[2 * cnt] = (data_ptr & NV_DPCD_ADJUST_REQ_LANEX_DC_MASK) >>
879 					NV_DPCD_ADJUST_REQ_LANEX_DC_SHIFT;
880 		pe[1 + 2 * cnt] =
881 			(data_ptr & NV_DPCD_ADJUST_REQ_LANEXPLUS1_PE_MASK) >>
882 					NV_DPCD_ADJUST_REQ_LANEXPLUS1_PE_SHIFT;
883 		vs[1 + 2 * cnt] =
884 			(data_ptr & NV_DPCD_ADJUST_REQ_LANEXPLUS1_DC_MASK) >>
885 					NV_DPCD_ADJUST_REQ_LANEXPLUS1_DC_SHIFT;
886 	}
887 	if (pc_supported) {
888 		ret = tegra_dc_dp_dpcd_read(dp, NV_DPCD_ADJUST_REQ_POST_CURSOR2,
889 					    &data_ptr);
890 		if (ret)
891 			return ret;
892 		for (cnt = 0; cnt < n_lanes; cnt++) {
893 			pc[cnt] = (data_ptr >>
894 			NV_DPCD_ADJUST_REQ_POST_CURSOR2_LANE_SHIFT(cnt)) &
895 			NV_DPCD_ADJUST_REQ_POST_CURSOR2_LANE_MASK;
896 		}
897 	}
898 
899 	return 0;
900 }
901 
902 static void tegra_dp_wait_aux_training(struct tegra_dp_priv *dp,
903 					bool is_clk_recovery,
904 					const struct tegra_dp_link_config *cfg)
905 {
906 	if (!cfg->aux_rd_interval)
907 		udelay(is_clk_recovery ? 200 : 500);
908 	else
909 		mdelay(cfg->aux_rd_interval * 4);
910 }
911 
912 static void tegra_dp_tpg(struct tegra_dp_priv *dp, u32 tp, u32 n_lanes,
913 			 const struct tegra_dp_link_config *cfg)
914 {
915 	u8 data = (tp == training_pattern_disabled)
916 		? (tp | NV_DPCD_TRAINING_PATTERN_SET_SC_DISABLED_F)
917 		: (tp | NV_DPCD_TRAINING_PATTERN_SET_SC_DISABLED_T);
918 
919 	tegra_dc_sor_set_dp_linkctl(dp->sor, 1, tp, cfg);
920 	tegra_dc_dp_dpcd_write(dp, DP_TRAINING_PATTERN_SET, data);
921 }
922 
923 static int tegra_dp_link_config(struct tegra_dp_priv *dp,
924 				const struct tegra_dp_link_config *link_cfg)
925 {
926 	u8 dpcd_data;
927 	u32 retry;
928 	int ret;
929 
930 	if (link_cfg->lane_count == 0) {
931 		debug("dp: error: lane count is 0. Can not set link config.\n");
932 		return -ENOLINK;
933 	}
934 
935 	/* Set power state if it is not in normal level */
936 	ret = tegra_dc_dp_dpcd_read(dp, DP_SET_POWER, &dpcd_data);
937 	if (ret)
938 		return ret;
939 
940 	if (dpcd_data == DP_SET_POWER_D3) {
941 		dpcd_data = DP_SET_POWER_D0;
942 
943 		/* DP spec requires 3 retries */
944 		for (retry = 3; retry > 0; --retry) {
945 			ret = tegra_dc_dp_dpcd_write(dp, DP_SET_POWER,
946 						     dpcd_data);
947 			if (!ret)
948 				break;
949 			if (retry == 1) {
950 				debug("dp: Failed to set DP panel power\n");
951 				return ret;
952 			}
953 		}
954 	}
955 
956 	/* Enable ASSR if possible */
957 	if (link_cfg->alt_scramber_reset_cap) {
958 		ret = tegra_dc_dp_set_assr(dp, dp->sor, 1);
959 		if (ret)
960 			return ret;
961 	}
962 
963 	ret = tegra_dp_set_link_bandwidth(dp, dp->sor, link_cfg->link_bw);
964 	if (ret) {
965 		debug("dp: Failed to set link bandwidth\n");
966 		return ret;
967 	}
968 	ret = tegra_dp_set_lane_count(dp, link_cfg, dp->sor);
969 	if (ret) {
970 		debug("dp: Failed to set lane count\n");
971 		return ret;
972 	}
973 	tegra_dc_sor_set_dp_linkctl(dp->sor, 1, training_pattern_none,
974 				    link_cfg);
975 
976 	return 0;
977 }
978 
979 static int tegra_dp_lower_link_config(struct tegra_dp_priv *dp,
980 				      const struct display_timing *timing,
981 				      struct tegra_dp_link_config *cfg)
982 {
983 	struct tegra_dp_link_config tmp_cfg;
984 	int ret;
985 
986 	tmp_cfg = *cfg;
987 	cfg->is_valid = 0;
988 
989 	ret = _tegra_dp_lower_link_config(dp, cfg);
990 	if (!ret)
991 		ret = tegra_dc_dp_calc_config(dp, timing, cfg);
992 	if (!ret)
993 		ret = tegra_dp_link_config(dp, cfg);
994 	if (ret)
995 		goto fail;
996 
997 	return 0;
998 
999 fail:
1000 	*cfg = tmp_cfg;
1001 	tegra_dp_link_config(dp, &tmp_cfg);
1002 	return ret;
1003 }
1004 
1005 static int tegra_dp_lt_config(struct tegra_dp_priv *dp, u32 pe[4], u32 vs[4],
1006 			      u32 pc[4], const struct tegra_dp_link_config *cfg)
1007 {
1008 	struct udevice *sor = dp->sor;
1009 	u32 n_lanes = cfg->lane_count;
1010 	u8 pc_supported = cfg->tps3_supported;
1011 	u32 cnt;
1012 	u32 val;
1013 
1014 	for (cnt = 0; cnt < n_lanes; cnt++) {
1015 		u32 mask = 0;
1016 		u32 pe_reg, vs_reg, pc_reg;
1017 		u32 shift = 0;
1018 
1019 		switch (cnt) {
1020 		case 0:
1021 			mask = PR_LANE2_DP_LANE0_MASK;
1022 			shift = PR_LANE2_DP_LANE0_SHIFT;
1023 			break;
1024 		case 1:
1025 			mask = PR_LANE1_DP_LANE1_MASK;
1026 			shift = PR_LANE1_DP_LANE1_SHIFT;
1027 			break;
1028 		case 2:
1029 			mask = PR_LANE0_DP_LANE2_MASK;
1030 			shift = PR_LANE0_DP_LANE2_SHIFT;
1031 			break;
1032 		case 3:
1033 			mask = PR_LANE3_DP_LANE3_MASK;
1034 			shift = PR_LANE3_DP_LANE3_SHIFT;
1035 			break;
1036 		default:
1037 			debug("dp: incorrect lane cnt\n");
1038 			return -EINVAL;
1039 		}
1040 
1041 		pe_reg = tegra_dp_pe_regs[pc[cnt]][vs[cnt]][pe[cnt]];
1042 		vs_reg = tegra_dp_vs_regs[pc[cnt]][vs[cnt]][pe[cnt]];
1043 		pc_reg = tegra_dp_pc_regs[pc[cnt]][vs[cnt]][pe[cnt]];
1044 
1045 		tegra_dp_set_pe_vs_pc(sor, mask, pe_reg << shift,
1046 				      vs_reg << shift, pc_reg << shift,
1047 				      pc_supported);
1048 	}
1049 
1050 	tegra_dp_disable_tx_pu(dp->sor);
1051 	udelay(20);
1052 
1053 	for (cnt = 0; cnt < n_lanes; cnt++) {
1054 		u32 max_vs_flag = tegra_dp_is_max_vs(pe[cnt], vs[cnt]);
1055 		u32 max_pe_flag = tegra_dp_is_max_pe(pe[cnt], vs[cnt]);
1056 
1057 		val = (vs[cnt] << NV_DPCD_TRAINING_LANEX_SET_DC_SHIFT) |
1058 			(max_vs_flag ?
1059 			NV_DPCD_TRAINING_LANEX_SET_DC_MAX_REACHED_T :
1060 			NV_DPCD_TRAINING_LANEX_SET_DC_MAX_REACHED_F) |
1061 			(pe[cnt] << NV_DPCD_TRAINING_LANEX_SET_PE_SHIFT) |
1062 			(max_pe_flag ?
1063 			NV_DPCD_TRAINING_LANEX_SET_PE_MAX_REACHED_T :
1064 			NV_DPCD_TRAINING_LANEX_SET_PE_MAX_REACHED_F);
1065 		tegra_dc_dp_dpcd_write(dp, (DP_TRAINING_LANE0_SET + cnt), val);
1066 	}
1067 
1068 	if (pc_supported) {
1069 		for (cnt = 0; cnt < n_lanes / 2; cnt++) {
1070 			u32 max_pc_flag0 = tegra_dp_is_max_pc(pc[cnt]);
1071 			u32 max_pc_flag1 = tegra_dp_is_max_pc(pc[cnt + 1]);
1072 			val = (pc[cnt] << NV_DPCD_LANEX_SET2_PC2_SHIFT) |
1073 				(max_pc_flag0 ?
1074 				NV_DPCD_LANEX_SET2_PC2_MAX_REACHED_T :
1075 				NV_DPCD_LANEX_SET2_PC2_MAX_REACHED_F) |
1076 				(pc[cnt + 1] <<
1077 				NV_DPCD_LANEXPLUS1_SET2_PC2_SHIFT) |
1078 				(max_pc_flag1 ?
1079 				NV_DPCD_LANEXPLUS1_SET2_PC2_MAX_REACHED_T :
1080 				NV_DPCD_LANEXPLUS1_SET2_PC2_MAX_REACHED_F);
1081 			tegra_dc_dp_dpcd_write(dp,
1082 					       NV_DPCD_TRAINING_LANE0_1_SET2 +
1083 					       cnt, val);
1084 		}
1085 	}
1086 
1087 	return 0;
1088 }
1089 
1090 static int _tegra_dp_channel_eq(struct tegra_dp_priv *dp, u32 pe[4],
1091 				u32 vs[4], u32 pc[4], u8 pc_supported,
1092 				u32 n_lanes,
1093 				const struct tegra_dp_link_config *cfg)
1094 {
1095 	u32 retry_cnt;
1096 
1097 	for (retry_cnt = 0; retry_cnt < 4; retry_cnt++) {
1098 		int ret;
1099 
1100 		if (retry_cnt) {
1101 			ret = tegra_dp_lt_adjust(dp, pe, vs, pc, pc_supported,
1102 						 cfg);
1103 			if (ret)
1104 				return ret;
1105 			tegra_dp_lt_config(dp, pe, vs, pc, cfg);
1106 		}
1107 
1108 		tegra_dp_wait_aux_training(dp, false, cfg);
1109 
1110 		if (!tegra_dp_clock_recovery_status(dp, cfg)) {
1111 			debug("dp: CR failed in channel EQ sequence!\n");
1112 			break;
1113 		}
1114 
1115 		if (!tegra_dp_channel_eq_status(dp, cfg))
1116 			return 0;
1117 	}
1118 
1119 	return -EIO;
1120 }
1121 
1122 static int tegra_dp_channel_eq(struct tegra_dp_priv *dp, u32 pe[4], u32 vs[4],
1123 			       u32 pc[4],
1124 			       const struct tegra_dp_link_config *cfg)
1125 {
1126 	u32 n_lanes = cfg->lane_count;
1127 	u8 pc_supported = cfg->tps3_supported;
1128 	int ret;
1129 	u32 tp_src = training_pattern_2;
1130 
1131 	if (pc_supported)
1132 		tp_src = training_pattern_3;
1133 
1134 	tegra_dp_tpg(dp, tp_src, n_lanes, cfg);
1135 
1136 	ret = _tegra_dp_channel_eq(dp, pe, vs, pc, pc_supported, n_lanes, cfg);
1137 
1138 	tegra_dp_tpg(dp, training_pattern_disabled, n_lanes, cfg);
1139 
1140 	return ret;
1141 }
1142 
1143 static int _tegra_dp_clk_recovery(struct tegra_dp_priv *dp, u32 pe[4],
1144 				  u32 vs[4], u32 pc[4], u8 pc_supported,
1145 				  u32 n_lanes,
1146 				  const struct tegra_dp_link_config *cfg)
1147 {
1148 	u32 vs_temp[4];
1149 	u32 retry_cnt = 0;
1150 
1151 	do {
1152 		tegra_dp_lt_config(dp, pe, vs, pc, cfg);
1153 		tegra_dp_wait_aux_training(dp, true, cfg);
1154 
1155 		if (tegra_dp_clock_recovery_status(dp, cfg))
1156 			return 0;
1157 
1158 		memcpy(vs_temp, vs, sizeof(vs_temp));
1159 		tegra_dp_lt_adjust(dp, pe, vs, pc, pc_supported, cfg);
1160 
1161 		if (memcmp(vs_temp, vs, sizeof(vs_temp)))
1162 			retry_cnt = 0;
1163 		else
1164 			++retry_cnt;
1165 	} while (retry_cnt < 5);
1166 
1167 	return -EIO;
1168 }
1169 
1170 static int tegra_dp_clk_recovery(struct tegra_dp_priv *dp, u32 pe[4],
1171 				 u32 vs[4], u32 pc[4],
1172 				 const struct tegra_dp_link_config *cfg)
1173 {
1174 	u32 n_lanes = cfg->lane_count;
1175 	u8 pc_supported = cfg->tps3_supported;
1176 	int err;
1177 
1178 	tegra_dp_tpg(dp, training_pattern_1, n_lanes, cfg);
1179 
1180 	err = _tegra_dp_clk_recovery(dp, pe, vs, pc, pc_supported, n_lanes,
1181 				     cfg);
1182 	if (err < 0)
1183 		tegra_dp_tpg(dp, training_pattern_disabled, n_lanes, cfg);
1184 
1185 	return err;
1186 }
1187 
1188 static int tegra_dc_dp_full_link_training(struct tegra_dp_priv *dp,
1189 					  const struct display_timing *timing,
1190 					  struct tegra_dp_link_config *cfg)
1191 {
1192 	struct udevice *sor = dp->sor;
1193 	int err;
1194 	u32 pe[4], vs[4], pc[4];
1195 
1196 	tegra_sor_precharge_lanes(sor, cfg);
1197 
1198 retry_cr:
1199 	memset(pe, PREEMPHASIS_DISABLED, sizeof(pe));
1200 	memset(vs, DRIVECURRENT_LEVEL0, sizeof(vs));
1201 	memset(pc, POSTCURSOR2_LEVEL0, sizeof(pc));
1202 
1203 	err = tegra_dp_clk_recovery(dp, pe, vs, pc, cfg);
1204 	if (err) {
1205 		if (!tegra_dp_lower_link_config(dp, timing, cfg))
1206 			goto retry_cr;
1207 
1208 		debug("dp: clk recovery failed\n");
1209 		goto fail;
1210 	}
1211 
1212 	err = tegra_dp_channel_eq(dp, pe, vs, pc, cfg);
1213 	if (err) {
1214 		if (!tegra_dp_lower_link_config(dp, timing, cfg))
1215 			goto retry_cr;
1216 
1217 		debug("dp: channel equalization failed\n");
1218 		goto fail;
1219 	}
1220 #ifdef DEBUG
1221 	tegra_dc_dp_dump_link_cfg(dp, cfg);
1222 #endif
1223 	return 0;
1224 
1225 fail:
1226 	return err;
1227 }
1228 
1229 /*
1230  * All link training functions are ported from kernel dc driver.
1231  * See more details at drivers/video/tegra/dc/dp.c
1232  */
1233 static int tegra_dc_dp_fast_link_training(struct tegra_dp_priv *dp,
1234 		const struct tegra_dp_link_config *link_cfg,
1235 		struct udevice *sor)
1236 {
1237 	u8	link_bw;
1238 	u8	lane_count;
1239 	u16	data16;
1240 	u32	data32;
1241 	u32	size;
1242 	u32	status;
1243 	int	j;
1244 	u32	mask = 0xffff >> ((4 - link_cfg->lane_count) * 4);
1245 
1246 	tegra_dc_sor_set_lane_parm(sor, link_cfg);
1247 	tegra_dc_dp_dpcd_write(dp, DP_MAIN_LINK_CHANNEL_CODING_SET,
1248 			       DP_SET_ANSI_8B10B);
1249 
1250 	/* Send TP1 */
1251 	tegra_dc_sor_set_dp_linkctl(sor, 1, training_pattern_1, link_cfg);
1252 	tegra_dc_dp_dpcd_write(dp, DP_TRAINING_PATTERN_SET,
1253 			       DP_TRAINING_PATTERN_1);
1254 
1255 	for (j = 0; j < link_cfg->lane_count; ++j)
1256 		tegra_dc_dp_dpcd_write(dp, DP_TRAINING_LANE0_SET + j, 0x24);
1257 	udelay(520);
1258 
1259 	size = sizeof(data16);
1260 	tegra_dc_dpaux_read(dp, DPAUX_DP_AUXCTL_CMD_AUXRD,
1261 			    DP_LANE0_1_STATUS, (u8 *)&data16, &size, &status);
1262 	status = mask & 0x1111;
1263 	if ((data16 & status) != status) {
1264 		debug("dp: Link training error for TP1 (%#x, status %#x)\n",
1265 		      data16, status);
1266 		return -EFAULT;
1267 	}
1268 
1269 	/* enable ASSR */
1270 	tegra_dc_dp_set_assr(dp, sor, link_cfg->scramble_ena);
1271 	tegra_dc_sor_set_dp_linkctl(sor, 1, training_pattern_3, link_cfg);
1272 
1273 	tegra_dc_dp_dpcd_write(dp, DP_TRAINING_PATTERN_SET,
1274 			       link_cfg->link_bw == 20 ? 0x23 : 0x22);
1275 	for (j = 0; j < link_cfg->lane_count; ++j)
1276 		tegra_dc_dp_dpcd_write(dp, DP_TRAINING_LANE0_SET + j, 0x24);
1277 	udelay(520);
1278 
1279 	size = sizeof(data32);
1280 	tegra_dc_dpaux_read(dp, DPAUX_DP_AUXCTL_CMD_AUXRD, DP_LANE0_1_STATUS,
1281 			    (u8 *)&data32, &size, &status);
1282 	if ((data32 & mask) != (0x7777 & mask)) {
1283 		debug("dp: Link training error for TP2/3 (0x%x)\n", data32);
1284 		return -EFAULT;
1285 	}
1286 
1287 	tegra_dc_sor_set_dp_linkctl(sor, 1, training_pattern_disabled,
1288 				    link_cfg);
1289 	tegra_dc_dp_dpcd_write(dp, DP_TRAINING_PATTERN_SET, 0);
1290 
1291 	if (tegra_dc_dp_link_trained(dp, link_cfg)) {
1292 		tegra_dc_sor_read_link_config(sor, &link_bw, &lane_count);
1293 		debug("Fast link training failed, link bw %d, lane # %d\n",
1294 		      link_bw, lane_count);
1295 		return -EFAULT;
1296 	}
1297 
1298 	debug("Fast link training succeeded, link bw %d, lane %d\n",
1299 	      link_cfg->link_bw, link_cfg->lane_count);
1300 
1301 	return 0;
1302 }
1303 
1304 static int tegra_dp_do_link_training(struct tegra_dp_priv *dp,
1305 		struct tegra_dp_link_config *link_cfg,
1306 		const struct display_timing *timing,
1307 		struct udevice *sor)
1308 {
1309 	u8	link_bw;
1310 	u8	lane_count;
1311 	int	ret;
1312 
1313 	if (DO_FAST_LINK_TRAINING) {
1314 		ret = tegra_dc_dp_fast_link_training(dp, link_cfg, sor);
1315 		if (ret) {
1316 			debug("dp: fast link training failed\n");
1317 		} else {
1318 			/*
1319 			* set to a known-good drive setting if fast link
1320 			* succeeded. Ignore any error.
1321 			*/
1322 			ret = tegra_dc_sor_set_voltage_swing(dp->sor, link_cfg);
1323 			if (ret)
1324 				debug("Failed to set voltage swing\n");
1325 		}
1326 	} else {
1327 		ret = -ENOSYS;
1328 	}
1329 	if (ret) {
1330 		/* Try full link training then */
1331 		ret = tegra_dc_dp_full_link_training(dp, timing, link_cfg);
1332 		if (ret) {
1333 			debug("dp: full link training failed\n");
1334 			return ret;
1335 		}
1336 	}
1337 
1338 	/* Everything is good; double check the link config */
1339 	tegra_dc_sor_read_link_config(sor, &link_bw, &lane_count);
1340 
1341 	if ((link_cfg->link_bw == link_bw) &&
1342 	    (link_cfg->lane_count == lane_count))
1343 		return 0;
1344 	else
1345 		return -EFAULT;
1346 }
1347 
1348 static int tegra_dc_dp_explore_link_cfg(struct tegra_dp_priv *dp,
1349 			struct tegra_dp_link_config *link_cfg,
1350 			struct udevice *sor,
1351 			const struct display_timing *timing)
1352 {
1353 	struct tegra_dp_link_config temp_cfg;
1354 
1355 	if (!timing->pixelclock.typ || !timing->hactive.typ ||
1356 	    !timing->vactive.typ) {
1357 		debug("dp: error mode configuration");
1358 		return -EINVAL;
1359 	}
1360 	if (!link_cfg->max_link_bw || !link_cfg->max_lane_count) {
1361 		debug("dp: error link configuration");
1362 		return -EINVAL;
1363 	}
1364 
1365 	link_cfg->is_valid = 0;
1366 
1367 	memcpy(&temp_cfg, link_cfg, sizeof(temp_cfg));
1368 
1369 	temp_cfg.link_bw = temp_cfg.max_link_bw;
1370 	temp_cfg.lane_count = temp_cfg.max_lane_count;
1371 
1372 	/*
1373 	 * set to max link config
1374 	 */
1375 	if ((!tegra_dc_dp_calc_config(dp, timing, &temp_cfg)) &&
1376 	    (!tegra_dp_link_config(dp, &temp_cfg)) &&
1377 		(!tegra_dp_do_link_training(dp, &temp_cfg, timing, sor)))
1378 		/* the max link cfg is doable */
1379 		memcpy(link_cfg, &temp_cfg, sizeof(temp_cfg));
1380 
1381 	return link_cfg->is_valid ? 0 : -EFAULT;
1382 }
1383 
1384 static int tegra_dp_hpd_plug(struct tegra_dp_priv *dp)
1385 {
1386 	const int vdd_to_hpd_delay_ms = 200;
1387 	u32 val;
1388 	ulong start;
1389 
1390 	start = get_timer(0);
1391 	do {
1392 		val = tegra_dpaux_readl(dp, DPAUX_DP_AUXSTAT);
1393 		if (val & DPAUX_DP_AUXSTAT_HPD_STATUS_PLUGGED)
1394 			return 0;
1395 		udelay(100);
1396 	} while (get_timer(start) < vdd_to_hpd_delay_ms);
1397 
1398 	return -EIO;
1399 }
1400 
1401 static int tegra_dc_dp_sink_out_of_sync(struct tegra_dp_priv *dp, u32 delay_ms)
1402 {
1403 	u8 dpcd_data;
1404 	int out_of_sync;
1405 	int ret;
1406 
1407 	debug("%s: delay=%d\n", __func__, delay_ms);
1408 	mdelay(delay_ms);
1409 	ret = tegra_dc_dp_dpcd_read(dp, DP_SINK_STATUS, &dpcd_data);
1410 	if (ret)
1411 		return ret;
1412 
1413 	out_of_sync = !(dpcd_data & DP_SINK_STATUS_PORT0_IN_SYNC);
1414 	if (out_of_sync)
1415 		debug("SINK receive port 0 out of sync, data=%x\n", dpcd_data);
1416 	else
1417 		debug("SINK is in synchronization\n");
1418 
1419 	return out_of_sync;
1420 }
1421 
1422 static int tegra_dc_dp_check_sink(struct tegra_dp_priv *dp,
1423 				  struct tegra_dp_link_config *link_cfg,
1424 				  const struct display_timing *timing)
1425 {
1426 	const int max_retry = 5;
1427 	int delay_frame;
1428 	int retries;
1429 
1430 	/*
1431 	 * DP TCON may skip some main stream frames, thus we need to wait
1432 	 * some delay before reading the DPCD SINK STATUS register, starting
1433 	 * from 5
1434 	 */
1435 	delay_frame = 5;
1436 
1437 	retries = max_retry;
1438 	do {
1439 		int ret;
1440 
1441 		if (!tegra_dc_dp_sink_out_of_sync(dp, link_cfg->frame_in_ms *
1442 						  delay_frame))
1443 			return 0;
1444 
1445 		debug("%s: retries left %d\n", __func__, retries);
1446 		if (!retries--) {
1447 			printf("DP: Out of sync after %d retries\n", max_retry);
1448 			return -EIO;
1449 		}
1450 		ret = tegra_dc_sor_detach(dp->dc_dev, dp->sor);
1451 		if (ret)
1452 			return ret;
1453 		if (tegra_dc_dp_explore_link_cfg(dp, link_cfg, dp->sor,
1454 						 timing)) {
1455 			debug("dp: %s: error to configure link\n", __func__);
1456 			continue;
1457 		}
1458 
1459 		tegra_dc_sor_set_power_state(dp->sor, 1);
1460 		tegra_dc_sor_attach(dp->dc_dev, dp->sor, link_cfg, timing);
1461 
1462 		/* Increase delay_frame for next try in case the sink is
1463 		   skipping more frames */
1464 		delay_frame += 10;
1465 	} while (1);
1466 }
1467 
1468 int tegra_dp_enable(struct udevice *dev, int panel_bpp,
1469 		    const struct display_timing *timing)
1470 {
1471 	struct tegra_dp_priv *priv = dev_get_priv(dev);
1472 	struct tegra_dp_link_config slink_cfg, *link_cfg = &slink_cfg;
1473 	struct udevice *sor;
1474 	int data;
1475 	int retry;
1476 	int ret;
1477 
1478 	memset(link_cfg, '\0', sizeof(*link_cfg));
1479 	link_cfg->is_valid = 0;
1480 	link_cfg->scramble_ena = 1;
1481 
1482 	tegra_dc_dpaux_enable(priv);
1483 
1484 	if (tegra_dp_hpd_plug(priv) < 0) {
1485 		debug("dp: hpd plug failed\n");
1486 		return -EIO;
1487 	}
1488 
1489 	link_cfg->bits_per_pixel = panel_bpp;
1490 	if (tegra_dc_dp_init_max_link_cfg(timing, priv, link_cfg)) {
1491 		debug("dp: failed to init link configuration\n");
1492 		return -ENOLINK;
1493 	}
1494 
1495 	ret = uclass_first_device(UCLASS_VIDEO_BRIDGE, &sor);
1496 	if (ret || !sor) {
1497 		debug("dp: failed to find SOR device: ret=%d\n", ret);
1498 		return ret;
1499 	}
1500 	priv->sor = sor;
1501 	ret = tegra_dc_sor_enable_dp(sor, link_cfg);
1502 	if (ret)
1503 		return ret;
1504 
1505 	tegra_dc_sor_set_panel_power(sor, 1);
1506 
1507 	/* Write power on to DPCD */
1508 	data = DP_SET_POWER_D0;
1509 	retry = 0;
1510 	do {
1511 		ret = tegra_dc_dp_dpcd_write(priv, DP_SET_POWER, data);
1512 	} while ((retry++ < DP_POWER_ON_MAX_TRIES) && ret);
1513 
1514 	if (ret || retry >= DP_POWER_ON_MAX_TRIES) {
1515 		debug("dp: failed to power on panel (0x%x)\n", ret);
1516 		return -ENETUNREACH;
1517 		goto error_enable;
1518 	}
1519 
1520 	/* Confirm DP plugging status */
1521 	if (!(tegra_dpaux_readl(priv, DPAUX_DP_AUXSTAT) &
1522 			DPAUX_DP_AUXSTAT_HPD_STATUS_PLUGGED)) {
1523 		debug("dp: could not detect HPD\n");
1524 		return -ENXIO;
1525 	}
1526 
1527 	/* Check DP version */
1528 	if (tegra_dc_dp_dpcd_read(priv, DP_DPCD_REV, &priv->revision)) {
1529 		debug("dp: failed to read the revision number from sink\n");
1530 		return -EIO;
1531 	}
1532 
1533 	if (tegra_dc_dp_explore_link_cfg(priv, link_cfg, sor, timing)) {
1534 		debug("dp: error configuring link\n");
1535 		return -ENOMEDIUM;
1536 	}
1537 
1538 	tegra_dc_sor_set_power_state(sor, 1);
1539 	ret = tegra_dc_sor_attach(priv->dc_dev, sor, link_cfg, timing);
1540 	if (ret && ret != -EEXIST)
1541 		return ret;
1542 
1543 	/*
1544 	 * This takes a long time, but can apparently resolve a failure to
1545 	 * bring up the display correctly.
1546 	 */
1547 	if (0) {
1548 		ret = tegra_dc_dp_check_sink(priv, link_cfg, timing);
1549 		if (ret)
1550 			return ret;
1551 	}
1552 
1553 	/* Power down the unused lanes to save power - a few hundred mW */
1554 	tegra_dc_sor_power_down_unused_lanes(sor, link_cfg);
1555 
1556 	ret = video_bridge_set_backlight(sor, 80);
1557 	if (ret) {
1558 		debug("dp: failed to set backlight\n");
1559 		return ret;
1560 	}
1561 
1562 	priv->enabled = true;
1563 error_enable:
1564 	return 0;
1565 }
1566 
1567 static int tegra_dp_ofdata_to_platdata(struct udevice *dev)
1568 {
1569 	struct tegra_dp_plat *plat = dev_get_platdata(dev);
1570 
1571 	plat->base = dev_read_addr(dev);
1572 
1573 	return 0;
1574 }
1575 
1576 static int tegra_dp_read_edid(struct udevice *dev, u8 *buf, int buf_size)
1577 {
1578 	struct tegra_dp_priv *priv = dev_get_priv(dev);
1579 	const int tegra_edid_i2c_address = 0x50;
1580 	u32 aux_stat = 0;
1581 
1582 	tegra_dc_dpaux_enable(priv);
1583 
1584 	return tegra_dc_i2c_aux_read(priv, tegra_edid_i2c_address, 0, buf,
1585 				     buf_size, &aux_stat);
1586 }
1587 
1588 static const struct dm_display_ops dp_tegra_ops = {
1589 	.read_edid = tegra_dp_read_edid,
1590 	.enable = tegra_dp_enable,
1591 };
1592 
1593 static int dp_tegra_probe(struct udevice *dev)
1594 {
1595 	struct tegra_dp_plat *plat = dev_get_platdata(dev);
1596 	struct tegra_dp_priv *priv = dev_get_priv(dev);
1597 	struct display_plat *disp_uc_plat = dev_get_uclass_platdata(dev);
1598 
1599 	priv->regs = (struct dpaux_ctlr *)plat->base;
1600 	priv->enabled = false;
1601 
1602 	/* Remember the display controller that is sending us video */
1603 	priv->dc_dev = disp_uc_plat->src_dev;
1604 
1605 	return 0;
1606 }
1607 
1608 static const struct udevice_id tegra_dp_ids[] = {
1609 	{ .compatible = "nvidia,tegra124-dpaux" },
1610 	{ }
1611 };
1612 
1613 U_BOOT_DRIVER(dp_tegra) = {
1614 	.name	= "dpaux_tegra",
1615 	.id	= UCLASS_DISPLAY,
1616 	.of_match = tegra_dp_ids,
1617 	.ofdata_to_platdata = tegra_dp_ofdata_to_platdata,
1618 	.probe	= dp_tegra_probe,
1619 	.ops	= &dp_tegra_ops,
1620 	.priv_auto_alloc_size = sizeof(struct tegra_dp_priv),
1621 	.platdata_auto_alloc_size = sizeof(struct tegra_dp_plat),
1622 };
1623