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1/*
2 * Copyright 2009 Red Hat Inc.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20 * OTHER DEALINGS IN THE SOFTWARE.
21 *
22 * Authors: Ben Skeggs
23 */
24
25#include "drmP.h"
26
27#include "nouveau_drv.h"
28#include "nouveau_i2c.h"
29#include "nouveau_connector.h"
30#include "nouveau_encoder.h"
31
32static int
33auxch_rd(struct drm_encoder *encoder, int address, uint8_t *buf, int size)
34{
35	struct drm_device *dev = encoder->dev;
36	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
37	struct nouveau_i2c_chan *auxch;
38	int ret;
39
40	auxch = nouveau_i2c_find(dev, nv_encoder->dcb->i2c_index);
41	if (!auxch)
42		return -ENODEV;
43
44	ret = nouveau_dp_auxch(auxch, 9, address, buf, size);
45	if (ret)
46		return ret;
47
48	return 0;
49}
50
51static int
52auxch_wr(struct drm_encoder *encoder, int address, uint8_t *buf, int size)
53{
54	struct drm_device *dev = encoder->dev;
55	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
56	struct nouveau_i2c_chan *auxch;
57	int ret;
58
59	auxch = nouveau_i2c_find(dev, nv_encoder->dcb->i2c_index);
60	if (!auxch)
61		return -ENODEV;
62
63	ret = nouveau_dp_auxch(auxch, 8, address, buf, size);
64	return ret;
65}
66
67static int
68nouveau_dp_lane_count_set(struct drm_encoder *encoder, uint8_t cmd)
69{
70	struct drm_device *dev = encoder->dev;
71	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
72	uint32_t tmp;
73	int or = nv_encoder->or, link = !(nv_encoder->dcb->sorconf.link & 1);
74
75	tmp  = nv_rd32(dev, NV50_SOR_DP_CTRL(or, link));
76	tmp &= ~(NV50_SOR_DP_CTRL_ENHANCED_FRAME_ENABLED |
77		 NV50_SOR_DP_CTRL_LANE_MASK);
78	tmp |= ((1 << (cmd & DP_LANE_COUNT_MASK)) - 1) << 16;
79	if (cmd & DP_LANE_COUNT_ENHANCED_FRAME_EN)
80		tmp |= NV50_SOR_DP_CTRL_ENHANCED_FRAME_ENABLED;
81	nv_wr32(dev, NV50_SOR_DP_CTRL(or, link), tmp);
82
83	return auxch_wr(encoder, DP_LANE_COUNT_SET, &cmd, 1);
84}
85
86static int
87nouveau_dp_link_bw_set(struct drm_encoder *encoder, uint8_t cmd)
88{
89	struct drm_device *dev = encoder->dev;
90	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
91	uint32_t tmp;
92	int reg = 0x614300 + (nv_encoder->or * 0x800);
93
94	tmp  = nv_rd32(dev, reg);
95	tmp &= 0xfff3ffff;
96	if (cmd == DP_LINK_BW_2_7)
97		tmp |= 0x00040000;
98	nv_wr32(dev, reg, tmp);
99
100	return auxch_wr(encoder, DP_LINK_BW_SET, &cmd, 1);
101}
102
103static int
104nouveau_dp_link_train_set(struct drm_encoder *encoder, int pattern)
105{
106	struct drm_device *dev = encoder->dev;
107	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
108	uint32_t tmp;
109	uint8_t cmd;
110	int or = nv_encoder->or, link = !(nv_encoder->dcb->sorconf.link & 1);
111	int ret;
112
113	tmp  = nv_rd32(dev, NV50_SOR_DP_CTRL(or, link));
114	tmp &= ~NV50_SOR_DP_CTRL_TRAINING_PATTERN;
115	tmp |= (pattern << 24);
116	nv_wr32(dev, NV50_SOR_DP_CTRL(or, link), tmp);
117
118	ret = auxch_rd(encoder, DP_TRAINING_PATTERN_SET, &cmd, 1);
119	if (ret)
120		return ret;
121	cmd &= ~DP_TRAINING_PATTERN_MASK;
122	cmd |= (pattern & DP_TRAINING_PATTERN_MASK);
123	return auxch_wr(encoder, DP_TRAINING_PATTERN_SET, &cmd, 1);
124}
125
126static int
127nouveau_dp_max_voltage_swing(struct drm_encoder *encoder)
128{
129	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
130	struct drm_device *dev = encoder->dev;
131	struct bit_displayport_encoder_table_entry *dpse;
132	struct bit_displayport_encoder_table *dpe;
133	int i, dpe_headerlen, max_vs = 0;
134
135	dpe = nouveau_bios_dp_table(dev, nv_encoder->dcb, &dpe_headerlen);
136	if (!dpe)
137		return false;
138	dpse = (void *)((char *)dpe + dpe_headerlen);
139
140	for (i = 0; i < dpe_headerlen; i++, dpse++) {
141		if (dpse->vs_level > max_vs)
142			max_vs = dpse->vs_level;
143	}
144
145	return max_vs;
146}
147
148static int
149nouveau_dp_max_pre_emphasis(struct drm_encoder *encoder, int vs)
150{
151	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
152	struct drm_device *dev = encoder->dev;
153	struct bit_displayport_encoder_table_entry *dpse;
154	struct bit_displayport_encoder_table *dpe;
155	int i, dpe_headerlen, max_pre = 0;
156
157	dpe = nouveau_bios_dp_table(dev, nv_encoder->dcb, &dpe_headerlen);
158	if (!dpe)
159		return false;
160	dpse = (void *)((char *)dpe + dpe_headerlen);
161
162	for (i = 0; i < dpe_headerlen; i++, dpse++) {
163		if (dpse->vs_level != vs)
164			continue;
165
166		if (dpse->pre_level > max_pre)
167			max_pre = dpse->pre_level;
168	}
169
170	return max_pre;
171}
172
173static bool
174nouveau_dp_link_train_adjust(struct drm_encoder *encoder, uint8_t *config)
175{
176	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
177	struct drm_device *dev = encoder->dev;
178	struct bit_displayport_encoder_table_entry *dpse;
179	struct bit_displayport_encoder_table *dpe;
180	int ret, i, dpe_headerlen, vs = 0, pre = 0;
181	uint8_t request[2];
182
183	dpe = nouveau_bios_dp_table(dev, nv_encoder->dcb, &dpe_headerlen);
184	if (!dpe)
185		return false;
186	dpse = (void *)((char *)dpe + dpe_headerlen);
187
188	ret = auxch_rd(encoder, DP_ADJUST_REQUEST_LANE0_1, request, 2);
189	if (ret)
190		return false;
191
192	NV_DEBUG_KMS(dev, "\t\tadjust 0x%02x 0x%02x\n", request[0], request[1]);
193
194	/* Keep all lanes at the same level.. */
195	for (i = 0; i < nv_encoder->dp.link_nr; i++) {
196		int lane_req = (request[i >> 1] >> ((i & 1) << 2)) & 0xf;
197		int lane_vs = lane_req & 3;
198		int lane_pre = (lane_req >> 2) & 3;
199
200		if (lane_vs > vs)
201			vs = lane_vs;
202		if (lane_pre > pre)
203			pre = lane_pre;
204	}
205
206	if (vs >= nouveau_dp_max_voltage_swing(encoder)) {
207		vs  = nouveau_dp_max_voltage_swing(encoder);
208		vs |= 4;
209	}
210
211	if (pre >= nouveau_dp_max_pre_emphasis(encoder, vs & 3)) {
212		pre  = nouveau_dp_max_pre_emphasis(encoder, vs & 3);
213		pre |= 4;
214	}
215
216	/* Update the configuration for all lanes.. */
217	for (i = 0; i < nv_encoder->dp.link_nr; i++)
218		config[i] = (pre << 3) | vs;
219
220	return true;
221}
222
223static bool
224nouveau_dp_link_train_commit(struct drm_encoder *encoder, uint8_t *config)
225{
226	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
227	struct drm_device *dev = encoder->dev;
228	struct bit_displayport_encoder_table_entry *dpse;
229	struct bit_displayport_encoder_table *dpe;
230	int or = nv_encoder->or, link = !(nv_encoder->dcb->sorconf.link & 1);
231	int dpe_headerlen, ret, i;
232
233	NV_DEBUG_KMS(dev, "\t\tconfig 0x%02x 0x%02x 0x%02x 0x%02x\n",
234		 config[0], config[1], config[2], config[3]);
235
236	dpe = nouveau_bios_dp_table(dev, nv_encoder->dcb, &dpe_headerlen);
237	if (!dpe)
238		return false;
239	dpse = (void *)((char *)dpe + dpe_headerlen);
240
241	for (i = 0; i < dpe->record_nr; i++, dpse++) {
242		if (dpse->vs_level == (config[0] & 3) &&
243		    dpse->pre_level == ((config[0] >> 3) & 3))
244			break;
245	}
246	BUG_ON(i == dpe->record_nr);
247
248	for (i = 0; i < nv_encoder->dp.link_nr; i++) {
249		const int shift[4] = { 16, 8, 0, 24 };
250		uint32_t mask = 0xff << shift[i];
251		uint32_t reg0, reg1, reg2;
252
253		reg0  = nv_rd32(dev, NV50_SOR_DP_UNK118(or, link)) & ~mask;
254		reg0 |= (dpse->reg0 << shift[i]);
255		reg1  = nv_rd32(dev, NV50_SOR_DP_UNK120(or, link)) & ~mask;
256		reg1 |= (dpse->reg1 << shift[i]);
257		reg2  = nv_rd32(dev, NV50_SOR_DP_UNK130(or, link)) & 0xffff00ff;
258		reg2 |= (dpse->reg2 << 8);
259		nv_wr32(dev, NV50_SOR_DP_UNK118(or, link), reg0);
260		nv_wr32(dev, NV50_SOR_DP_UNK120(or, link), reg1);
261		nv_wr32(dev, NV50_SOR_DP_UNK130(or, link), reg2);
262	}
263
264	ret = auxch_wr(encoder, DP_TRAINING_LANE0_SET, config, 4);
265	if (ret)
266		return false;
267
268	return true;
269}
270
271bool
272nouveau_dp_link_train(struct drm_encoder *encoder)
273{
274	struct drm_device *dev = encoder->dev;
275	struct drm_nouveau_private *dev_priv = dev->dev_private;
276	struct nouveau_gpio_engine *pgpio = &dev_priv->engine.gpio;
277	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
278	struct nouveau_connector *nv_connector;
279	struct bit_displayport_encoder_table *dpe;
280	int dpe_headerlen;
281	uint8_t config[4], status[3];
282	bool cr_done, cr_max_vs, eq_done;
283	int ret = 0, i, tries, voltage;
284
285	NV_DEBUG_KMS(dev, "link training!!\n");
286
287	nv_connector = nouveau_encoder_connector_get(nv_encoder);
288	if (!nv_connector)
289		return false;
290
291	dpe = nouveau_bios_dp_table(dev, nv_encoder->dcb, &dpe_headerlen);
292	if (!dpe) {
293		NV_ERROR(dev, "SOR-%d: no DP encoder table!\n", nv_encoder->or);
294		return false;
295	}
296
297	/* disable hotplug detect, this flips around on some panels during
298	 * link training.
299	 */
300	pgpio->irq_enable(dev, nv_connector->dcb->gpio_tag, false);
301
302	if (dpe->script0) {
303		NV_DEBUG_KMS(dev, "SOR-%d: running DP script 0\n", nv_encoder->or);
304		nouveau_bios_run_init_table(dev, le16_to_cpu(dpe->script0),
305					    nv_encoder->dcb);
306	}
307
308train:
309	cr_done = eq_done = false;
310
311	/* set link configuration */
312	NV_DEBUG_KMS(dev, "\tbegin train: bw %d, lanes %d\n",
313		 nv_encoder->dp.link_bw, nv_encoder->dp.link_nr);
314
315	ret = nouveau_dp_link_bw_set(encoder, nv_encoder->dp.link_bw);
316	if (ret)
317		return false;
318
319	config[0] = nv_encoder->dp.link_nr;
320	if (nv_encoder->dp.dpcd_version >= 0x11)
321		config[0] |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
322
323	ret = nouveau_dp_lane_count_set(encoder, config[0]);
324	if (ret)
325		return false;
326
327	/* clock recovery */
328	NV_DEBUG_KMS(dev, "\tbegin cr\n");
329	ret = nouveau_dp_link_train_set(encoder, DP_TRAINING_PATTERN_1);
330	if (ret)
331		goto stop;
332
333	tries = 0;
334	voltage = -1;
335	memset(config, 0x00, sizeof(config));
336	for (;;) {
337		if (!nouveau_dp_link_train_commit(encoder, config))
338			break;
339
340		udelay(100);
341
342		ret = auxch_rd(encoder, DP_LANE0_1_STATUS, status, 2);
343		if (ret)
344			break;
345		NV_DEBUG_KMS(dev, "\t\tstatus: 0x%02x 0x%02x\n",
346			 status[0], status[1]);
347
348		cr_done = true;
349		cr_max_vs = false;
350		for (i = 0; i < nv_encoder->dp.link_nr; i++) {
351			int lane = (status[i >> 1] >> ((i & 1) * 4)) & 0xf;
352
353			if (!(lane & DP_LANE_CR_DONE)) {
354				cr_done = false;
355				if (config[i] & DP_TRAIN_MAX_PRE_EMPHASIS_REACHED)
356					cr_max_vs = true;
357				break;
358			}
359		}
360
361		if ((config[0] & DP_TRAIN_VOLTAGE_SWING_MASK) != voltage) {
362			voltage = config[0] & DP_TRAIN_VOLTAGE_SWING_MASK;
363			tries = 0;
364		}
365
366		if (cr_done || cr_max_vs || (++tries == 5))
367			break;
368
369		if (!nouveau_dp_link_train_adjust(encoder, config))
370			break;
371	}
372
373	if (!cr_done)
374		goto stop;
375
376	/* channel equalisation */
377	NV_DEBUG_KMS(dev, "\tbegin eq\n");
378	ret = nouveau_dp_link_train_set(encoder, DP_TRAINING_PATTERN_2);
379	if (ret)
380		goto stop;
381
382	for (tries = 0; tries <= 5; tries++) {
383		udelay(400);
384
385		ret = auxch_rd(encoder, DP_LANE0_1_STATUS, status, 3);
386		if (ret)
387			break;
388		NV_DEBUG_KMS(dev, "\t\tstatus: 0x%02x 0x%02x\n",
389			 status[0], status[1]);
390
391		eq_done = true;
392		if (!(status[2] & DP_INTERLANE_ALIGN_DONE))
393			eq_done = false;
394
395		for (i = 0; eq_done && i < nv_encoder->dp.link_nr; i++) {
396			int lane = (status[i >> 1] >> ((i & 1) * 4)) & 0xf;
397
398			if (!(lane & DP_LANE_CR_DONE)) {
399				cr_done = false;
400				break;
401			}
402
403			if (!(lane & DP_LANE_CHANNEL_EQ_DONE) ||
404			    !(lane & DP_LANE_SYMBOL_LOCKED)) {
405				eq_done = false;
406				break;
407			}
408		}
409
410		if (eq_done || !cr_done)
411			break;
412
413		if (!nouveau_dp_link_train_adjust(encoder, config) ||
414		    !nouveau_dp_link_train_commit(encoder, config))
415			break;
416	}
417
418stop:
419	/* end link training */
420	ret = nouveau_dp_link_train_set(encoder, DP_TRAINING_PATTERN_DISABLE);
421	if (ret)
422		return false;
423
424	/* retry at a lower setting, if possible */
425	if (!ret && !(eq_done && cr_done)) {
426		NV_DEBUG_KMS(dev, "\twe failed\n");
427		if (nv_encoder->dp.link_bw != DP_LINK_BW_1_62) {
428			NV_DEBUG_KMS(dev, "retry link training at low rate\n");
429			nv_encoder->dp.link_bw = DP_LINK_BW_1_62;
430			goto train;
431		}
432	}
433
434	if (dpe->script1) {
435		NV_DEBUG_KMS(dev, "SOR-%d: running DP script 1\n", nv_encoder->or);
436		nouveau_bios_run_init_table(dev, le16_to_cpu(dpe->script1),
437					    nv_encoder->dcb);
438	}
439
440	/* re-enable hotplug detect */
441	pgpio->irq_enable(dev, nv_connector->dcb->gpio_tag, true);
442
443	return eq_done;
444}
445
446bool
447nouveau_dp_detect(struct drm_encoder *encoder)
448{
449	struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
450	struct drm_device *dev = encoder->dev;
451	uint8_t dpcd[4];
452	int ret;
453
454	ret = auxch_rd(encoder, 0x0000, dpcd, 4);
455	if (ret)
456		return false;
457
458	NV_DEBUG_KMS(dev, "encoder: link_bw %d, link_nr %d\n"
459		      "display: link_bw %d, link_nr %d version 0x%02x\n",
460		 nv_encoder->dcb->dpconf.link_bw,
461		 nv_encoder->dcb->dpconf.link_nr,
462		 dpcd[1], dpcd[2] & 0x0f, dpcd[0]);
463
464	nv_encoder->dp.dpcd_version = dpcd[0];
465
466	nv_encoder->dp.link_bw = dpcd[1];
467	if (nv_encoder->dp.link_bw != DP_LINK_BW_1_62 &&
468	    !nv_encoder->dcb->dpconf.link_bw)
469		nv_encoder->dp.link_bw = DP_LINK_BW_1_62;
470
471	nv_encoder->dp.link_nr = dpcd[2] & 0xf;
472	if (nv_encoder->dp.link_nr > nv_encoder->dcb->dpconf.link_nr)
473		nv_encoder->dp.link_nr = nv_encoder->dcb->dpconf.link_nr;
474
475	return true;
476}
477
478int
479nouveau_dp_auxch(struct nouveau_i2c_chan *auxch, int cmd, int addr,
480		 uint8_t *data, int data_nr)
481{
482	struct drm_device *dev = auxch->dev;
483	uint32_t tmp, ctrl, stat = 0, data32[4] = {};
484	int ret = 0, i, index = auxch->rd;
485
486	NV_DEBUG_KMS(dev, "ch %d cmd %d addr 0x%x len %d\n", index, cmd, addr, data_nr);
487
488	tmp = nv_rd32(dev, NV50_AUXCH_CTRL(auxch->rd));
489	nv_wr32(dev, NV50_AUXCH_CTRL(auxch->rd), tmp | 0x00100000);
490	tmp = nv_rd32(dev, NV50_AUXCH_CTRL(auxch->rd));
491	if (!(tmp & 0x01000000)) {
492		NV_ERROR(dev, "expected bit 24 == 1, got 0x%08x\n", tmp);
493		ret = -EIO;
494		goto out;
495	}
496
497	for (i = 0; i < 3; i++) {
498		tmp = nv_rd32(dev, NV50_AUXCH_STAT(auxch->rd));
499		if (tmp & NV50_AUXCH_STAT_STATE_READY)
500			break;
501		udelay(100);
502	}
503
504	if (i == 3) {
505		ret = -EBUSY;
506		goto out;
507	}
508
509	if (!(cmd & 1)) {
510		memcpy(data32, data, data_nr);
511		for (i = 0; i < 4; i++) {
512			NV_DEBUG_KMS(dev, "wr %d: 0x%08x\n", i, data32[i]);
513			nv_wr32(dev, NV50_AUXCH_DATA_OUT(index, i), data32[i]);
514		}
515	}
516
517	nv_wr32(dev, NV50_AUXCH_ADDR(index), addr);
518	ctrl  = nv_rd32(dev, NV50_AUXCH_CTRL(index));
519	ctrl &= ~(NV50_AUXCH_CTRL_CMD | NV50_AUXCH_CTRL_LEN);
520	ctrl |= (cmd << NV50_AUXCH_CTRL_CMD_SHIFT);
521	ctrl |= ((data_nr - 1) << NV50_AUXCH_CTRL_LEN_SHIFT);
522
523	for (i = 0; i < 16; i++) {
524		nv_wr32(dev, NV50_AUXCH_CTRL(index), ctrl | 0x80000000);
525		nv_wr32(dev, NV50_AUXCH_CTRL(index), ctrl);
526		nv_wr32(dev, NV50_AUXCH_CTRL(index), ctrl | 0x00010000);
527		if (!nv_wait(NV50_AUXCH_CTRL(index), 0x00010000, 0x00000000)) {
528			NV_ERROR(dev, "expected bit 16 == 0, got 0x%08x\n",
529				 nv_rd32(dev, NV50_AUXCH_CTRL(index)));
530			ret = -EBUSY;
531			goto out;
532		}
533
534		udelay(400);
535
536		stat = nv_rd32(dev, NV50_AUXCH_STAT(index));
537		if ((stat & NV50_AUXCH_STAT_REPLY_AUX) !=
538			    NV50_AUXCH_STAT_REPLY_AUX_DEFER)
539			break;
540	}
541
542	if (i == 16) {
543		NV_ERROR(dev, "auxch DEFER too many times, bailing\n");
544		ret = -EREMOTEIO;
545		goto out;
546	}
547
548	if (cmd & 1) {
549		if ((stat & NV50_AUXCH_STAT_COUNT) != data_nr) {
550			ret = -EREMOTEIO;
551			goto out;
552		}
553
554		for (i = 0; i < 4; i++) {
555			data32[i] = nv_rd32(dev, NV50_AUXCH_DATA_IN(index, i));
556			NV_DEBUG_KMS(dev, "rd %d: 0x%08x\n", i, data32[i]);
557		}
558		memcpy(data, data32, data_nr);
559	}
560
561out:
562	tmp = nv_rd32(dev, NV50_AUXCH_CTRL(auxch->rd));
563	nv_wr32(dev, NV50_AUXCH_CTRL(auxch->rd), tmp & ~0x00100000);
564	tmp = nv_rd32(dev, NV50_AUXCH_CTRL(auxch->rd));
565	if (tmp & 0x01000000) {
566		NV_ERROR(dev, "expected bit 24 == 0, got 0x%08x\n", tmp);
567		ret = -EIO;
568	}
569
570	udelay(400);
571
572	return ret ? ret : (stat & NV50_AUXCH_STAT_REPLY);
573}
574
575static int
576nouveau_dp_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
577{
578	struct nouveau_i2c_chan *auxch = (struct nouveau_i2c_chan *)adap;
579	struct drm_device *dev = auxch->dev;
580	struct i2c_msg *msg = msgs;
581	int ret, mcnt = num;
582
583	while (mcnt--) {
584		u8 remaining = msg->len;
585		u8 *ptr = msg->buf;
586
587		while (remaining) {
588			u8 cnt = (remaining > 16) ? 16 : remaining;
589			u8 cmd;
590
591			if (msg->flags & I2C_M_RD)
592				cmd = AUX_I2C_READ;
593			else
594				cmd = AUX_I2C_WRITE;
595
596			if (mcnt || remaining > 16)
597				cmd |= AUX_I2C_MOT;
598
599			ret = nouveau_dp_auxch(auxch, cmd, msg->addr, ptr, cnt);
600			if (ret < 0)
601				return ret;
602
603			switch (ret & NV50_AUXCH_STAT_REPLY_I2C) {
604			case NV50_AUXCH_STAT_REPLY_I2C_ACK:
605				break;
606			case NV50_AUXCH_STAT_REPLY_I2C_NACK:
607				return -EREMOTEIO;
608			case NV50_AUXCH_STAT_REPLY_I2C_DEFER:
609				udelay(100);
610				continue;
611			default:
612				NV_ERROR(dev, "bad auxch reply: 0x%08x\n", ret);
613				return -EREMOTEIO;
614			}
615
616			ptr += cnt;
617			remaining -= cnt;
618		}
619
620		msg++;
621	}
622
623	return num;
624}
625
626static u32
627nouveau_dp_i2c_func(struct i2c_adapter *adap)
628{
629	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
630}
631
632const struct i2c_algorithm nouveau_dp_i2c_algo = {
633	.master_xfer = nouveau_dp_i2c_xfer,
634	.functionality = nouveau_dp_i2c_func
635};
636