nouveau_dp.c 16.2 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
/*
 * Copyright 2009 Red Hat Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * Authors: Ben Skeggs
 */

#include "drmP.h"
26

27 28
#include "nouveau_drv.h"
#include "nouveau_i2c.h"
29
#include "nouveau_connector.h"
30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191
#include "nouveau_encoder.h"

static int
auxch_rd(struct drm_encoder *encoder, int address, uint8_t *buf, int size)
{
	struct drm_device *dev = encoder->dev;
	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
	struct nouveau_i2c_chan *auxch;
	int ret;

	auxch = nouveau_i2c_find(dev, nv_encoder->dcb->i2c_index);
	if (!auxch)
		return -ENODEV;

	ret = nouveau_dp_auxch(auxch, 9, address, buf, size);
	if (ret)
		return ret;

	return 0;
}

static int
auxch_wr(struct drm_encoder *encoder, int address, uint8_t *buf, int size)
{
	struct drm_device *dev = encoder->dev;
	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
	struct nouveau_i2c_chan *auxch;
	int ret;

	auxch = nouveau_i2c_find(dev, nv_encoder->dcb->i2c_index);
	if (!auxch)
		return -ENODEV;

	ret = nouveau_dp_auxch(auxch, 8, address, buf, size);
	return ret;
}

static int
nouveau_dp_lane_count_set(struct drm_encoder *encoder, uint8_t cmd)
{
	struct drm_device *dev = encoder->dev;
	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
	uint32_t tmp;
	int or = nv_encoder->or, link = !(nv_encoder->dcb->sorconf.link & 1);

	tmp  = nv_rd32(dev, NV50_SOR_DP_CTRL(or, link));
	tmp &= ~(NV50_SOR_DP_CTRL_ENHANCED_FRAME_ENABLED |
		 NV50_SOR_DP_CTRL_LANE_MASK);
	tmp |= ((1 << (cmd & DP_LANE_COUNT_MASK)) - 1) << 16;
	if (cmd & DP_LANE_COUNT_ENHANCED_FRAME_EN)
		tmp |= NV50_SOR_DP_CTRL_ENHANCED_FRAME_ENABLED;
	nv_wr32(dev, NV50_SOR_DP_CTRL(or, link), tmp);

	return auxch_wr(encoder, DP_LANE_COUNT_SET, &cmd, 1);
}

static int
nouveau_dp_link_bw_set(struct drm_encoder *encoder, uint8_t cmd)
{
	struct drm_device *dev = encoder->dev;
	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
	uint32_t tmp;
	int reg = 0x614300 + (nv_encoder->or * 0x800);

	tmp  = nv_rd32(dev, reg);
	tmp &= 0xfff3ffff;
	if (cmd == DP_LINK_BW_2_7)
		tmp |= 0x00040000;
	nv_wr32(dev, reg, tmp);

	return auxch_wr(encoder, DP_LINK_BW_SET, &cmd, 1);
}

static int
nouveau_dp_link_train_set(struct drm_encoder *encoder, int pattern)
{
	struct drm_device *dev = encoder->dev;
	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
	uint32_t tmp;
	uint8_t cmd;
	int or = nv_encoder->or, link = !(nv_encoder->dcb->sorconf.link & 1);
	int ret;

	tmp  = nv_rd32(dev, NV50_SOR_DP_CTRL(or, link));
	tmp &= ~NV50_SOR_DP_CTRL_TRAINING_PATTERN;
	tmp |= (pattern << 24);
	nv_wr32(dev, NV50_SOR_DP_CTRL(or, link), tmp);

	ret = auxch_rd(encoder, DP_TRAINING_PATTERN_SET, &cmd, 1);
	if (ret)
		return ret;
	cmd &= ~DP_TRAINING_PATTERN_MASK;
	cmd |= (pattern & DP_TRAINING_PATTERN_MASK);
	return auxch_wr(encoder, DP_TRAINING_PATTERN_SET, &cmd, 1);
}

static int
nouveau_dp_max_voltage_swing(struct drm_encoder *encoder)
{
	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
	struct drm_device *dev = encoder->dev;
	struct bit_displayport_encoder_table_entry *dpse;
	struct bit_displayport_encoder_table *dpe;
	int i, dpe_headerlen, max_vs = 0;

	dpe = nouveau_bios_dp_table(dev, nv_encoder->dcb, &dpe_headerlen);
	if (!dpe)
		return false;
	dpse = (void *)((char *)dpe + dpe_headerlen);

	for (i = 0; i < dpe_headerlen; i++, dpse++) {
		if (dpse->vs_level > max_vs)
			max_vs = dpse->vs_level;
	}

	return max_vs;
}

static int
nouveau_dp_max_pre_emphasis(struct drm_encoder *encoder, int vs)
{
	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
	struct drm_device *dev = encoder->dev;
	struct bit_displayport_encoder_table_entry *dpse;
	struct bit_displayport_encoder_table *dpe;
	int i, dpe_headerlen, max_pre = 0;

	dpe = nouveau_bios_dp_table(dev, nv_encoder->dcb, &dpe_headerlen);
	if (!dpe)
		return false;
	dpse = (void *)((char *)dpe + dpe_headerlen);

	for (i = 0; i < dpe_headerlen; i++, dpse++) {
		if (dpse->vs_level != vs)
			continue;

		if (dpse->pre_level > max_pre)
			max_pre = dpse->pre_level;
	}

	return max_pre;
}

static bool
nouveau_dp_link_train_adjust(struct drm_encoder *encoder, uint8_t *config)
{
	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
	struct drm_device *dev = encoder->dev;
	struct bit_displayport_encoder_table_entry *dpse;
	struct bit_displayport_encoder_table *dpe;
	int ret, i, dpe_headerlen, vs = 0, pre = 0;
	uint8_t request[2];

	dpe = nouveau_bios_dp_table(dev, nv_encoder->dcb, &dpe_headerlen);
	if (!dpe)
		return false;
	dpse = (void *)((char *)dpe + dpe_headerlen);

	ret = auxch_rd(encoder, DP_ADJUST_REQUEST_LANE0_1, request, 2);
	if (ret)
		return false;

192
	NV_DEBUG_KMS(dev, "\t\tadjust 0x%02x 0x%02x\n", request[0], request[1]);
193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232

	/* Keep all lanes at the same level.. */
	for (i = 0; i < nv_encoder->dp.link_nr; i++) {
		int lane_req = (request[i >> 1] >> ((i & 1) << 2)) & 0xf;
		int lane_vs = lane_req & 3;
		int lane_pre = (lane_req >> 2) & 3;

		if (lane_vs > vs)
			vs = lane_vs;
		if (lane_pre > pre)
			pre = lane_pre;
	}

	if (vs >= nouveau_dp_max_voltage_swing(encoder)) {
		vs  = nouveau_dp_max_voltage_swing(encoder);
		vs |= 4;
	}

	if (pre >= nouveau_dp_max_pre_emphasis(encoder, vs & 3)) {
		pre  = nouveau_dp_max_pre_emphasis(encoder, vs & 3);
		pre |= 4;
	}

	/* Update the configuration for all lanes.. */
	for (i = 0; i < nv_encoder->dp.link_nr; i++)
		config[i] = (pre << 3) | vs;

	return true;
}

static bool
nouveau_dp_link_train_commit(struct drm_encoder *encoder, uint8_t *config)
{
	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
	struct drm_device *dev = encoder->dev;
	struct bit_displayport_encoder_table_entry *dpse;
	struct bit_displayport_encoder_table *dpe;
	int or = nv_encoder->or, link = !(nv_encoder->dcb->sorconf.link & 1);
	int dpe_headerlen, ret, i;

233
	NV_DEBUG_KMS(dev, "\t\tconfig 0x%02x 0x%02x 0x%02x 0x%02x\n",
234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275
		 config[0], config[1], config[2], config[3]);

	dpe = nouveau_bios_dp_table(dev, nv_encoder->dcb, &dpe_headerlen);
	if (!dpe)
		return false;
	dpse = (void *)((char *)dpe + dpe_headerlen);

	for (i = 0; i < dpe->record_nr; i++, dpse++) {
		if (dpse->vs_level == (config[0] & 3) &&
		    dpse->pre_level == ((config[0] >> 3) & 3))
			break;
	}
	BUG_ON(i == dpe->record_nr);

	for (i = 0; i < nv_encoder->dp.link_nr; i++) {
		const int shift[4] = { 16, 8, 0, 24 };
		uint32_t mask = 0xff << shift[i];
		uint32_t reg0, reg1, reg2;

		reg0  = nv_rd32(dev, NV50_SOR_DP_UNK118(or, link)) & ~mask;
		reg0 |= (dpse->reg0 << shift[i]);
		reg1  = nv_rd32(dev, NV50_SOR_DP_UNK120(or, link)) & ~mask;
		reg1 |= (dpse->reg1 << shift[i]);
		reg2  = nv_rd32(dev, NV50_SOR_DP_UNK130(or, link)) & 0xffff00ff;
		reg2 |= (dpse->reg2 << 8);
		nv_wr32(dev, NV50_SOR_DP_UNK118(or, link), reg0);
		nv_wr32(dev, NV50_SOR_DP_UNK120(or, link), reg1);
		nv_wr32(dev, NV50_SOR_DP_UNK130(or, link), reg2);
	}

	ret = auxch_wr(encoder, DP_TRAINING_LANE0_SET, config, 4);
	if (ret)
		return false;

	return true;
}

bool
nouveau_dp_link_train(struct drm_encoder *encoder)
{
	struct drm_device *dev = encoder->dev;
	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
276
	struct nouveau_connector *nv_connector;
277 278 279
	struct bit_displayport_encoder_table *dpe;
	int dpe_headerlen;
	uint8_t config[4], status[3];
280 281 282
	bool cr_done, cr_max_vs, eq_done;
	int ret = 0, i, tries, voltage;

283
	NV_DEBUG_KMS(dev, "link training!!\n");
284

285 286 287 288
	nv_connector = nouveau_encoder_connector_get(nv_encoder);
	if (!nv_connector)
		return false;

289 290 291 292 293 294
	dpe = nouveau_bios_dp_table(dev, nv_encoder->dcb, &dpe_headerlen);
	if (!dpe) {
		NV_ERROR(dev, "SOR-%d: no DP encoder table!\n", nv_encoder->or);
		return false;
	}

295 296 297 298 299
	/* disable hotplug detect, this flips around on some panels during
	 * link training.
	 */
	nv50_gpio_irq_enable(dev, nv_connector->dcb->gpio_tag, false);

300 301 302 303 304 305
	if (dpe->script0) {
		NV_DEBUG_KMS(dev, "SOR-%d: running DP script 0\n", nv_encoder->or);
		nouveau_bios_run_init_table(dev, le16_to_cpu(dpe->script0),
					    nv_encoder->dcb);
	}

306 307 308 309
train:
	cr_done = eq_done = false;

	/* set link configuration */
310
	NV_DEBUG_KMS(dev, "\tbegin train: bw %d, lanes %d\n",
311 312 313 314 315 316 317 318 319 320 321 322 323 324 325
		 nv_encoder->dp.link_bw, nv_encoder->dp.link_nr);

	ret = nouveau_dp_link_bw_set(encoder, nv_encoder->dp.link_bw);
	if (ret)
		return false;

	config[0] = nv_encoder->dp.link_nr;
	if (nv_encoder->dp.dpcd_version >= 0x11)
		config[0] |= DP_LANE_COUNT_ENHANCED_FRAME_EN;

	ret = nouveau_dp_lane_count_set(encoder, config[0]);
	if (ret)
		return false;

	/* clock recovery */
326
	NV_DEBUG_KMS(dev, "\tbegin cr\n");
327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342
	ret = nouveau_dp_link_train_set(encoder, DP_TRAINING_PATTERN_1);
	if (ret)
		goto stop;

	tries = 0;
	voltage = -1;
	memset(config, 0x00, sizeof(config));
	for (;;) {
		if (!nouveau_dp_link_train_commit(encoder, config))
			break;

		udelay(100);

		ret = auxch_rd(encoder, DP_LANE0_1_STATUS, status, 2);
		if (ret)
			break;
343
		NV_DEBUG_KMS(dev, "\t\tstatus: 0x%02x 0x%02x\n",
344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374
			 status[0], status[1]);

		cr_done = true;
		cr_max_vs = false;
		for (i = 0; i < nv_encoder->dp.link_nr; i++) {
			int lane = (status[i >> 1] >> ((i & 1) * 4)) & 0xf;

			if (!(lane & DP_LANE_CR_DONE)) {
				cr_done = false;
				if (config[i] & DP_TRAIN_MAX_PRE_EMPHASIS_REACHED)
					cr_max_vs = true;
				break;
			}
		}

		if ((config[0] & DP_TRAIN_VOLTAGE_SWING_MASK) != voltage) {
			voltage = config[0] & DP_TRAIN_VOLTAGE_SWING_MASK;
			tries = 0;
		}

		if (cr_done || cr_max_vs || (++tries == 5))
			break;

		if (!nouveau_dp_link_train_adjust(encoder, config))
			break;
	}

	if (!cr_done)
		goto stop;

	/* channel equalisation */
375
	NV_DEBUG_KMS(dev, "\tbegin eq\n");
376 377 378 379 380 381 382 383 384 385
	ret = nouveau_dp_link_train_set(encoder, DP_TRAINING_PATTERN_2);
	if (ret)
		goto stop;

	for (tries = 0; tries <= 5; tries++) {
		udelay(400);

		ret = auxch_rd(encoder, DP_LANE0_1_STATUS, status, 3);
		if (ret)
			break;
386
		NV_DEBUG_KMS(dev, "\t\tstatus: 0x%02x 0x%02x\n",
387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423
			 status[0], status[1]);

		eq_done = true;
		if (!(status[2] & DP_INTERLANE_ALIGN_DONE))
			eq_done = false;

		for (i = 0; eq_done && i < nv_encoder->dp.link_nr; i++) {
			int lane = (status[i >> 1] >> ((i & 1) * 4)) & 0xf;

			if (!(lane & DP_LANE_CR_DONE)) {
				cr_done = false;
				break;
			}

			if (!(lane & DP_LANE_CHANNEL_EQ_DONE) ||
			    !(lane & DP_LANE_SYMBOL_LOCKED)) {
				eq_done = false;
				break;
			}
		}

		if (eq_done || !cr_done)
			break;

		if (!nouveau_dp_link_train_adjust(encoder, config) ||
		    !nouveau_dp_link_train_commit(encoder, config))
			break;
	}

stop:
	/* end link training */
	ret = nouveau_dp_link_train_set(encoder, DP_TRAINING_PATTERN_DISABLE);
	if (ret)
		return false;

	/* retry at a lower setting, if possible */
	if (!ret && !(eq_done && cr_done)) {
424
		NV_DEBUG_KMS(dev, "\twe failed\n");
425
		if (nv_encoder->dp.link_bw != DP_LINK_BW_1_62) {
426
			NV_DEBUG_KMS(dev, "retry link training at low rate\n");
427 428 429 430 431
			nv_encoder->dp.link_bw = DP_LINK_BW_1_62;
			goto train;
		}
	}

432 433 434 435 436 437
	if (dpe->script1) {
		NV_DEBUG_KMS(dev, "SOR-%d: running DP script 1\n", nv_encoder->or);
		nouveau_bios_run_init_table(dev, le16_to_cpu(dpe->script1),
					    nv_encoder->dcb);
	}

438 439 440
	/* re-enable hotplug detect */
	nv50_gpio_irq_enable(dev, nv_connector->dcb->gpio_tag, true);

441 442 443 444 445 446 447 448 449 450 451 452 453 454 455
	return eq_done;
}

bool
nouveau_dp_detect(struct drm_encoder *encoder)
{
	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
	struct drm_device *dev = encoder->dev;
	uint8_t dpcd[4];
	int ret;

	ret = auxch_rd(encoder, 0x0000, dpcd, 4);
	if (ret)
		return false;

456
	NV_DEBUG_KMS(dev, "encoder: link_bw %d, link_nr %d\n"
457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483
		      "display: link_bw %d, link_nr %d version 0x%02x\n",
		 nv_encoder->dcb->dpconf.link_bw,
		 nv_encoder->dcb->dpconf.link_nr,
		 dpcd[1], dpcd[2] & 0x0f, dpcd[0]);

	nv_encoder->dp.dpcd_version = dpcd[0];

	nv_encoder->dp.link_bw = dpcd[1];
	if (nv_encoder->dp.link_bw != DP_LINK_BW_1_62 &&
	    !nv_encoder->dcb->dpconf.link_bw)
		nv_encoder->dp.link_bw = DP_LINK_BW_1_62;

	nv_encoder->dp.link_nr = dpcd[2] & 0xf;
	if (nv_encoder->dp.link_nr > nv_encoder->dcb->dpconf.link_nr)
		nv_encoder->dp.link_nr = nv_encoder->dcb->dpconf.link_nr;

	return true;
}

int
nouveau_dp_auxch(struct nouveau_i2c_chan *auxch, int cmd, int addr,
		 uint8_t *data, int data_nr)
{
	struct drm_device *dev = auxch->dev;
	uint32_t tmp, ctrl, stat = 0, data32[4] = {};
	int ret = 0, i, index = auxch->rd;

484
	NV_DEBUG_KMS(dev, "ch %d cmd %d addr 0x%x len %d\n", index, cmd, addr, data_nr);
485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509

	tmp = nv_rd32(dev, NV50_AUXCH_CTRL(auxch->rd));
	nv_wr32(dev, NV50_AUXCH_CTRL(auxch->rd), tmp | 0x00100000);
	tmp = nv_rd32(dev, NV50_AUXCH_CTRL(auxch->rd));
	if (!(tmp & 0x01000000)) {
		NV_ERROR(dev, "expected bit 24 == 1, got 0x%08x\n", tmp);
		ret = -EIO;
		goto out;
	}

	for (i = 0; i < 3; i++) {
		tmp = nv_rd32(dev, NV50_AUXCH_STAT(auxch->rd));
		if (tmp & NV50_AUXCH_STAT_STATE_READY)
			break;
		udelay(100);
	}

	if (i == 3) {
		ret = -EBUSY;
		goto out;
	}

	if (!(cmd & 1)) {
		memcpy(data32, data, data_nr);
		for (i = 0; i < 4; i++) {
510
			NV_DEBUG_KMS(dev, "wr %d: 0x%08x\n", i, data32[i]);
511 512 513 514 515 516 517 518 519 520
			nv_wr32(dev, NV50_AUXCH_DATA_OUT(index, i), data32[i]);
		}
	}

	nv_wr32(dev, NV50_AUXCH_ADDR(index), addr);
	ctrl  = nv_rd32(dev, NV50_AUXCH_CTRL(index));
	ctrl &= ~(NV50_AUXCH_CTRL_CMD | NV50_AUXCH_CTRL_LEN);
	ctrl |= (cmd << NV50_AUXCH_CTRL_CMD_SHIFT);
	ctrl |= ((data_nr - 1) << NV50_AUXCH_CTRL_LEN_SHIFT);

521
	for (i = 0; i < 16; i++) {
522 523 524 525 526 527
		nv_wr32(dev, NV50_AUXCH_CTRL(index), ctrl | 0x80000000);
		nv_wr32(dev, NV50_AUXCH_CTRL(index), ctrl);
		nv_wr32(dev, NV50_AUXCH_CTRL(index), ctrl | 0x00010000);
		if (!nv_wait(NV50_AUXCH_CTRL(index), 0x00010000, 0x00000000)) {
			NV_ERROR(dev, "expected bit 16 == 0, got 0x%08x\n",
				 nv_rd32(dev, NV50_AUXCH_CTRL(index)));
528 529
			ret = -EBUSY;
			goto out;
530 531 532 533 534 535 536 537 538 539
		}

		udelay(400);

		stat = nv_rd32(dev, NV50_AUXCH_STAT(index));
		if ((stat & NV50_AUXCH_STAT_REPLY_AUX) !=
			    NV50_AUXCH_STAT_REPLY_AUX_DEFER)
			break;
	}

540 541 542 543 544 545
	if (i == 16) {
		NV_ERROR(dev, "auxch DEFER too many times, bailing\n");
		ret = -EREMOTEIO;
		goto out;
	}

546
	if (cmd & 1) {
547 548 549 550 551
		if ((stat & NV50_AUXCH_STAT_COUNT) != data_nr) {
			ret = -EREMOTEIO;
			goto out;
		}

552 553
		for (i = 0; i < 4; i++) {
			data32[i] = nv_rd32(dev, NV50_AUXCH_DATA_IN(index, i));
554
			NV_DEBUG_KMS(dev, "rd %d: 0x%08x\n", i, data32[i]);
555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616
		}
		memcpy(data, data32, data_nr);
	}

out:
	tmp = nv_rd32(dev, NV50_AUXCH_CTRL(auxch->rd));
	nv_wr32(dev, NV50_AUXCH_CTRL(auxch->rd), tmp & ~0x00100000);
	tmp = nv_rd32(dev, NV50_AUXCH_CTRL(auxch->rd));
	if (tmp & 0x01000000) {
		NV_ERROR(dev, "expected bit 24 == 0, got 0x%08x\n", tmp);
		ret = -EIO;
	}

	udelay(400);

	return ret ? ret : (stat & NV50_AUXCH_STAT_REPLY);
}

int
nouveau_dp_i2c_aux_ch(struct i2c_adapter *adapter, int mode,
		      uint8_t write_byte, uint8_t *read_byte)
{
	struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;
	struct nouveau_i2c_chan *auxch = (struct nouveau_i2c_chan *)adapter;
	struct drm_device *dev = auxch->dev;
	int ret = 0, cmd, addr = algo_data->address;
	uint8_t *buf;

	if (mode == MODE_I2C_READ) {
		cmd = AUX_I2C_READ;
		buf = read_byte;
	} else {
		cmd = (mode & MODE_I2C_READ) ? AUX_I2C_READ : AUX_I2C_WRITE;
		buf = &write_byte;
	}

	if (!(mode & MODE_I2C_STOP))
		cmd |= AUX_I2C_MOT;

	if (mode & MODE_I2C_START)
		return 1;

	for (;;) {
		ret = nouveau_dp_auxch(auxch, cmd, addr, buf, 1);
		if (ret < 0)
			return ret;

		switch (ret & NV50_AUXCH_STAT_REPLY_I2C) {
		case NV50_AUXCH_STAT_REPLY_I2C_ACK:
			return 1;
		case NV50_AUXCH_STAT_REPLY_I2C_NACK:
			return -EREMOTEIO;
		case NV50_AUXCH_STAT_REPLY_I2C_DEFER:
			udelay(100);
			break;
		default:
			NV_ERROR(dev, "invalid auxch status: 0x%08x\n", ret);
			return -EREMOTEIO;
		}
	}
}