drivers/gpu/drm/nouveau/nouveau_dp.c

   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 #include "nouveau_crtc.h"
  32 #include "nouveau_gpio.h"
  33
  34 /******************************************************************************
  35  * aux channel util functions
  36  *****************************************************************************/
  37 #define AUX_DBG(fmt, args...) do {                                             \
  38         if (nouveau_reg_debug & NOUVEAU_REG_DEBUG_AUXCH) {                     \
  39                 NV_PRINTK(KERN_DEBUG, dev, "AUXCH(%d): " fmt, ch, ##args);     \
  40         }                                                                      \
  41 } while (0)
  42 #define AUX_ERR(fmt, args...) NV_ERROR(dev, "AUXCH(%d): " fmt, ch, ##args)
  43
  44 static void
  45 auxch_fini(struct drm_device *dev, int ch)
  46 {
  47         nv_mask(dev, 0x00e4e4 + (ch * 0x50), 0x00310000, 0x00000000);
  48 }
  49
  50 static int
  51 auxch_init(struct drm_device *dev, int ch)
  52 {
  53         const u32 unksel = 1; /* nfi which to use, or if it matters.. */
  54         const u32 ureq = unksel ? 0x00100000 : 0x00200000;
  55         const u32 urep = unksel ? 0x01000000 : 0x02000000;
  56         u32 ctrl, timeout;
  57
  58         /* wait up to 1ms for any previous transaction to be done... */
  59         timeout = 1000;
  60         do {
  61                 ctrl = nv_rd32(dev, 0x00e4e4 + (ch * 0x50));
  62                 udelay(1);
  63                 if (!timeout--) {
  64                         AUX_ERR("begin idle timeout 0x%08x", ctrl);
  65                         return -EBUSY;
  66                 }
  67         } while (ctrl & 0x03010000);
  68
  69         /* set some magic, and wait up to 1ms for it to appear */
  70         nv_mask(dev, 0x00e4e4 + (ch * 0x50), 0x00300000, ureq);
  71         timeout = 1000;
  72         do {
  73                 ctrl = nv_rd32(dev, 0x00e4e4 + (ch * 0x50));
  74                 udelay(1);
  75                 if (!timeout--) {
  76                         AUX_ERR("magic wait 0x%08x\n", ctrl);
  77                         auxch_fini(dev, ch);
  78                         return -EBUSY;
  79                 }
  80         } while ((ctrl & 0x03000000) != urep);
  81
  82         return 0;
  83 }
  84
  85 static int
  86 auxch_tx(struct drm_device *dev, int ch, u8 type, u32 addr, u8 *data, u8 size)
  87 {
  88         u32 ctrl, stat, timeout, retries;
  89         u32 xbuf[4] = {};
  90         int ret, i;
  91
  92         AUX_DBG("%d: 0x%08x %d\n", type, addr, size);
  93
  94         ret = auxch_init(dev, ch);
  95         if (ret)
  96                 goto out;
  97
  98         stat = nv_rd32(dev, 0x00e4e8 + (ch * 0x50));
  99         if (!(stat & 0x10000000)) {
 100                 AUX_DBG("sink not detected\n");
 101                 ret = -ENXIO;
 102                 goto out;
 103         }
 104
 105         if (!(type & 1)) {
 106                 memcpy(xbuf, data, size);
 107                 for (i = 0; i < 16; i += 4) {
 108                         AUX_DBG("wr 0x%08x\n", xbuf[i / 4]);
 109                         nv_wr32(dev, 0x00e4c0 + (ch * 0x50) + i, xbuf[i / 4]);
 110                 }
 111         }
 112
 113         ctrl  = nv_rd32(dev, 0x00e4e4 + (ch * 0x50));
 114         ctrl &= ~0x0001f0ff;
 115         ctrl |= type << 12;
 116         ctrl |= size - 1;
 117         nv_wr32(dev, 0x00e4e0 + (ch * 0x50), addr);
 118
 119         /* retry transaction a number of times on failure... */
 120         ret = -EREMOTEIO;
 121         for (retries = 0; retries < 32; retries++) {
 122                 /* reset, and delay a while if this is a retry */
 123                 nv_wr32(dev, 0x00e4e4 + (ch * 0x50), 0x80000000 | ctrl);
 124                 nv_wr32(dev, 0x00e4e4 + (ch * 0x50), 0x00000000 | ctrl);
 125                 if (retries)
 126                         udelay(400);
 127
 128                 /* transaction request, wait up to 1ms for it to complete */
 129                 nv_wr32(dev, 0x00e4e4 + (ch * 0x50), 0x00010000 | ctrl);
 130
 131                 timeout = 1000;
 132                 do {
 133                         ctrl = nv_rd32(dev, 0x00e4e4 + (ch * 0x50));
 134                         udelay(1);
 135                         if (!timeout--) {
 136                                 AUX_ERR("tx req timeout 0x%08x\n", ctrl);
 137                                 goto out;
 138                         }
 139                 } while (ctrl & 0x00010000);
 140
 141                 /* read status, and check if transaction completed ok */
 142                 stat = nv_mask(dev, 0x00e4e8 + (ch * 0x50), 0, 0);
 143                 if (!(stat & 0x000f0f00)) {
 144                         ret = 0;
 145                         break;
 146                 }
 147
 148                 AUX_DBG("%02d 0x%08x 0x%08x\n", retries, ctrl, stat);
 149         }
 150
 151         if (type & 1) {
 152                 for (i = 0; i < 16; i += 4) {
 153                         xbuf[i / 4] = nv_rd32(dev, 0x00e4d0 + (ch * 0x50) + i);
 154                         AUX_DBG("rd 0x%08x\n", xbuf[i / 4]);
 155                 }
 156                 memcpy(data, xbuf, size);
 157         }
 158
 159 out:
 160         auxch_fini(dev, ch);
 161         return ret;
 162 }
 163
 164 u8 *
 165 nouveau_dp_bios_data(struct drm_device *dev, struct dcb_entry *dcb, u8 **entry)
 166 {
 167         struct bit_entry d;
 168         u8 *table;
 169         int i;
 170
 171         if (bit_table(dev, 'd', &d)) {
 172                 NV_ERROR(dev, "BIT 'd' table not found\n");
 173                 return NULL;
 174         }
 175
 176         if (d.version != 1) {
 177                 NV_ERROR(dev, "BIT 'd' table version %d unknown\n", d.version);
 178                 return NULL;
 179         }
 180
 181         table = ROMPTR(dev, d.data[0]);
 182         if (!table) {
 183                 NV_ERROR(dev, "displayport table pointer invalid\n");
 184                 return NULL;
 185         }
 186
 187         switch (table[0]) {
 188         case 0x20:
 189         case 0x21:
 190         case 0x30:
 191         case 0x40:
 192                 break;
 193         default:
 194                 NV_ERROR(dev, "displayport table 0x%02x unknown\n", table[0]);
 195                 return NULL;
 196         }
 197
 198         for (i = 0; i < table[3]; i++) {
 199                 *entry = ROMPTR(dev, table[table[1] + (i * table[2])]);
 200                 if (*entry && bios_encoder_match(dcb, ROM32((*entry)[0])))
 201                         return table;
 202         }
 203
 204         NV_ERROR(dev, "displayport encoder table not found\n");
 205         return NULL;
 206 }
 207
 208 /******************************************************************************
 209  * link training
 210  *****************************************************************************/
 211 struct dp_state {
 212         struct dp_train_func *func;
 213         struct dcb_entry *dcb;
 214         int auxch;
 215         int crtc;
 216         u8 *dpcd;
 217         int link_nr;
 218         u32 link_bw;
 219         u8  stat[6];
 220         u8  conf[4];
 221 };
 222
 223 static void
 224 dp_set_link_config(struct drm_device *dev, struct dp_state *dp)
 225 {
 226         u8 sink[2];
 227
 228         NV_DEBUG_KMS(dev, "%d lanes at %d KB/s\n", dp->link_nr, dp->link_bw);
 229
 230         /* set desired link configuration on the source */
 231         dp->func->link_set(dev, dp->dcb, dp->crtc, dp->link_nr, dp->link_bw,
 232                            dp->dpcd[2] & DP_ENHANCED_FRAME_CAP);
 233
 234         /* inform the sink of the new configuration */
 235         sink[0] = dp->link_bw / 27000;
 236         sink[1] = dp->link_nr;
 237         if (dp->dpcd[2] & DP_ENHANCED_FRAME_CAP)
 238                 sink[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
 239
 240         auxch_tx(dev, dp->auxch, 8, DP_LINK_BW_SET, sink, 2);
 241 }
 242
 243 static void
 244 dp_set_training_pattern(struct drm_device *dev, struct dp_state *dp, u8 pattern)
 245 {
 246         u8 sink_tp;
 247
 248         NV_DEBUG_KMS(dev, "training pattern %d\n", pattern);
 249
 250         dp->func->train_set(dev, dp->dcb, pattern);
 251
 252         auxch_tx(dev, dp->auxch, 9, DP_TRAINING_PATTERN_SET, &sink_tp, 1);
 253         sink_tp &= ~DP_TRAINING_PATTERN_MASK;
 254         sink_tp |= pattern;
 255         auxch_tx(dev, dp->auxch, 8, DP_TRAINING_PATTERN_SET, &sink_tp, 1);
 256 }
 257
 258 static int
 259 dp_link_train_commit(struct drm_device *dev, struct dp_state *dp)
 260 {
 261         int i;
 262
 263         for (i = 0; i < dp->link_nr; i++) {
 264                 u8 lane = (dp->stat[4 + (i >> 1)] >> ((i & 1) * 4)) & 0xf;
 265                 u8 lpre = (lane & 0x0c) >> 2;
 266                 u8 lvsw = (lane & 0x03) >> 0;
 267
 268                 dp->conf[i] = (lpre << 3) | lvsw;
 269                 if (lvsw == DP_TRAIN_VOLTAGE_SWING_1200)
 270                         dp->conf[i] |= DP_TRAIN_MAX_SWING_REACHED;
 271                 if ((lpre << 3) == DP_TRAIN_PRE_EMPHASIS_9_5)
 272                         dp->conf[i] |= DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
 273
 274                 NV_DEBUG_KMS(dev, "config lane %d %02x\n", i, dp->conf[i]);
 275                 dp->func->train_adj(dev, dp->dcb, i, lvsw, lpre);
 276         }
 277
 278         return auxch_tx(dev, dp->auxch, 8, DP_TRAINING_LANE0_SET, dp->conf, 4);
 279 }
 280
 281 static int
 282 dp_link_train_update(struct drm_device *dev, struct dp_state *dp, u32 delay)
 283 {
 284         int ret;
 285
 286         udelay(delay);
 287
 288         ret = auxch_tx(dev, dp->auxch, 9, DP_LANE0_1_STATUS, dp->stat, 6);
 289         if (ret)
 290                 return ret;
 291
 292         NV_DEBUG_KMS(dev, "status %02x %02x %02x %02x %02x %02x\n",
 293                      dp->stat[0], dp->stat[1], dp->stat[2], dp->stat[3],
 294                      dp->stat[4], dp->stat[5]);
 295         return 0;
 296 }
 297
 298 static int
 299 dp_link_train_cr(struct drm_device *dev, struct dp_state *dp)
 300 {
 301         bool cr_done = false, abort = false;
 302         int voltage = dp->conf[0] & DP_TRAIN_VOLTAGE_SWING_MASK;
 303         int tries = 0, i;
 304
 305         dp_set_training_pattern(dev, dp, DP_TRAINING_PATTERN_1);
 306
 307         do {
 308                 if (dp_link_train_commit(dev, dp) ||
 309                     dp_link_train_update(dev, dp, 100))
 310                         break;
 311
 312                 cr_done = true;
 313                 for (i = 0; i < dp->link_nr; i++) {
 314                         u8 lane = (dp->stat[i >> 1] >> ((i & 1) * 4)) & 0xf;
 315                         if (!(lane & DP_LANE_CR_DONE)) {
 316                                 cr_done = false;
 317                                 if (dp->conf[i] & DP_TRAIN_MAX_SWING_REACHED)
 318                                         abort = true;
 319                                 break;
 320                         }
 321                 }
 322
 323                 if ((dp->conf[0] & DP_TRAIN_VOLTAGE_SWING_MASK) != voltage) {
 324                         voltage = dp->conf[0] & DP_TRAIN_VOLTAGE_SWING_MASK;
 325                         tries = 0;
 326                 }
 327         } while (!cr_done && !abort && ++tries < 5);
 328
 329         return cr_done ? 0 : -1;
 330 }
 331
 332 static int
 333 dp_link_train_eq(struct drm_device *dev, struct dp_state *dp)
 334 {
 335         bool eq_done, cr_done = true;
 336         int tries = 0, i;
 337
 338         dp_set_training_pattern(dev, dp, DP_TRAINING_PATTERN_2);
 339
 340         do {
 341                 if (dp_link_train_update(dev, dp, 400))
 342                         break;
 343
 344                 eq_done = !!(dp->stat[2] & DP_INTERLANE_ALIGN_DONE);
 345                 for (i = 0; i < dp->link_nr && eq_done; i++) {
 346                         u8 lane = (dp->stat[i >> 1] >> ((i & 1) * 4)) & 0xf;
 347                         if (!(lane & DP_LANE_CR_DONE))
 348                                 cr_done = false;
 349                         if (!(lane & DP_LANE_CHANNEL_EQ_DONE) ||
 350                             !(lane & DP_LANE_SYMBOL_LOCKED))
 351                                 eq_done = false;
 352                 }
 353
 354                 if (dp_link_train_commit(dev, dp))
 355                         break;
 356         } while (!eq_done && cr_done && ++tries <= 5);
 357
 358         return eq_done ? 0 : -1;
 359 }
 360
 361 static void
 362 dp_set_downspread(struct drm_device *dev, struct dp_state *dp, bool enable)
 363 {
 364         u16 script = 0x0000;
 365         u8 *entry, *table = nouveau_dp_bios_data(dev, dp->dcb, &entry);
 366         if (table) {
 367                 if (table[0] >= 0x20 && table[0] <= 0x30) {
 368                         if (enable) script = ROM16(entry[12]);
 369                         else        script = ROM16(entry[14]);
 370                 } else
 371                 if (table[0] == 0x40) {
 372                         if (enable) script = ROM16(entry[11]);
 373                         else        script = ROM16(entry[13]);
 374                 }
 375         }
 376
 377         nouveau_bios_run_init_table(dev, script, dp->dcb, dp->crtc);
 378 }
 379
 380 static void
 381 dp_link_train_init(struct drm_device *dev, struct dp_state *dp)
 382 {
 383         u16 script = 0x0000;
 384         u8 *entry, *table = nouveau_dp_bios_data(dev, dp->dcb, &entry);
 385         if (table) {
 386                 if (table[0] >= 0x20 && table[0] <= 0x30)
 387                         script = ROM16(entry[6]);
 388                 else
 389                 if (table[0] == 0x40)
 390                         script = ROM16(entry[5]);
 391         }
 392
 393         nouveau_bios_run_init_table(dev, script, dp->dcb, dp->crtc);
 394 }
 395
 396 static void
 397 dp_link_train_fini(struct drm_device *dev, struct dp_state *dp)
 398 {
 399         u16 script = 0x0000;
 400         u8 *entry, *table = nouveau_dp_bios_data(dev, dp->dcb, &entry);
 401         if (table) {
 402                 if (table[0] >= 0x20 && table[0] <= 0x30)
 403                         script = ROM16(entry[8]);
 404                 else
 405                 if (table[0] == 0x40)
 406                         script = ROM16(entry[7]);
 407         }
 408
 409         nouveau_bios_run_init_table(dev, script, dp->dcb, dp->crtc);
 410 }
 411
 412 bool
 413 nouveau_dp_link_train(struct drm_encoder *encoder, u32 datarate,
 414                       struct dp_train_func *func)
 415 {
 416         struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
 417         struct nouveau_crtc *nv_crtc = nouveau_crtc(encoder->crtc);
 418         struct nouveau_connector *nv_connector =
 419                 nouveau_encoder_connector_get(nv_encoder);
 420         struct drm_device *dev = encoder->dev;
 421         struct nouveau_i2c_chan *auxch;
 422         const u32 bw_list[] = { 270000, 162000, 0 };
 423         const u32 *link_bw = bw_list;
 424         struct dp_state dp;
 425
 426         auxch = nouveau_i2c_find(dev, nv_encoder->dcb->i2c_index);
 427         if (!auxch)
 428                 return false;
 429
 430         dp.func = func;
 431         dp.dcb = nv_encoder->dcb;
 432         dp.crtc = nv_crtc->index;
 433         dp.auxch = auxch->drive;
 434         dp.dpcd = nv_encoder->dp.dpcd;
 435
 436         /* adjust required bandwidth for 8B/10B coding overhead */
 437         datarate = (datarate / 8) * 10;
 438
 439         /* some sinks toggle hotplug in response to some of the actions
 440          * we take during link training (DP_SET_POWER is one), we need
 441          * to ignore them for the moment to avoid races.
 442          */
 443         nouveau_gpio_irq(dev, 0, nv_connector->hpd, 0xff, false);
 444
 445         /* enable down-spreading, if possible */
 446         dp_set_downspread(dev, &dp, nv_encoder->dp.dpcd[3] & 1);
 447
 448         /* execute pre-train script from vbios */
 449         dp_link_train_init(dev, &dp);
 450
 451         /* start off at highest link rate supported by encoder and display */
 452         while (*link_bw > nv_encoder->dp.link_bw)
 453                 link_bw++;
 454
 455         while (link_bw[0]) {
 456                 /* find minimum required lane count at this link rate */
 457                 dp.link_nr = nv_encoder->dp.link_nr;
 458                 while ((dp.link_nr >> 1) * link_bw[0] > datarate)
 459                         dp.link_nr >>= 1;
 460
 461                 /* drop link rate to minimum with this lane count */
 462                 while ((link_bw[1] * dp.link_nr) > datarate)
 463                         link_bw++;
 464                 dp.link_bw = link_bw[0];
 465
 466                 /* program selected link configuration */
 467                 dp_set_link_config(dev, &dp);
 468
 469                 /* attempt to train the link at this configuration */
 470                 memset(dp.stat, 0x00, sizeof(dp.stat));
 471                 if (!dp_link_train_cr(dev, &dp) &&
 472                     !dp_link_train_eq(dev, &dp))
 473                         break;
 474
 475                 /* retry at lower rate */
 476                 link_bw++;
 477         }
 478
 479         /* finish link training */
 480         dp_set_training_pattern(dev, &dp, DP_TRAINING_PATTERN_DISABLE);
 481
 482         /* execute post-train script from vbios */
 483         dp_link_train_fini(dev, &dp);
 484
 485         /* re-enable hotplug detect */
 486         nouveau_gpio_irq(dev, 0, nv_connector->hpd, 0xff, true);
 487         return true;
 488 }
 489
 490 void
 491 nouveau_dp_dpms(struct drm_encoder *encoder, int mode, u32 datarate,
 492                 struct dp_train_func *func)
 493 {
 494         struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
 495         struct nouveau_i2c_chan *auxch;
 496         u8 status;
 497
 498         auxch = nouveau_i2c_find(encoder->dev, nv_encoder->dcb->i2c_index);
 499         if (!auxch)
 500                 return;
 501
 502         if (mode == DRM_MODE_DPMS_ON)
 503                 status = DP_SET_POWER_D0;
 504         else
 505                 status = DP_SET_POWER_D3;
 506
 507         nouveau_dp_auxch(auxch, 8, DP_SET_POWER, &status, 1);
 508
 509         if (mode == DRM_MODE_DPMS_ON)
 510                 nouveau_dp_link_train(encoder, datarate, func);
 511 }
 512
 513 static void
 514 nouveau_dp_probe_oui(struct drm_device *dev, struct nouveau_i2c_chan *auxch,
 515                      u8 *dpcd)
 516 {
 517         u8 buf[3];
 518
 519         if (!(dpcd[DP_DOWN_STREAM_PORT_COUNT] & DP_OUI_SUPPORT))
 520                 return;
 521
 522         if (!auxch_tx(dev, auxch->drive, 9, DP_SINK_OUI, buf, 3))
 523                 NV_DEBUG_KMS(dev, "Sink OUI: %02hx%02hx%02hx\n",
 524                              buf[0], buf[1], buf[2]);
 525
 526         if (!auxch_tx(dev, auxch->drive, 9, DP_BRANCH_OUI, buf, 3))
 527                 NV_DEBUG_KMS(dev, "Branch OUI: %02hx%02hx%02hx\n",
 528                              buf[0], buf[1], buf[2]);
 529
 530 }
 531
 532 bool
 533 nouveau_dp_detect(struct drm_encoder *encoder)
 534 {
 535         struct nouveau_encoder *nv_encoder = nouveau_encoder(encoder);
 536         struct drm_device *dev = encoder->dev;
 537         struct nouveau_i2c_chan *auxch;
 538         u8 *dpcd = nv_encoder->dp.dpcd;
 539         int ret;
 540
 541         auxch = nouveau_i2c_find(dev, nv_encoder->dcb->i2c_index);
 542         if (!auxch)
 543                 return false;
 544
 545         ret = auxch_tx(dev, auxch->drive, 9, DP_DPCD_REV, dpcd, 8);
 546         if (ret)
 547                 return false;
 548
 549         nv_encoder->dp.link_bw = 27000 * dpcd[1];
 550         nv_encoder->dp.link_nr = dpcd[2] & DP_MAX_LANE_COUNT_MASK;
 551
 552         NV_DEBUG_KMS(dev, "display: %dx%d dpcd 0x%02x\n",
 553                      nv_encoder->dp.link_nr, nv_encoder->dp.link_bw, dpcd[0]);
 554         NV_DEBUG_KMS(dev, "encoder: %dx%d\n",
 555                      nv_encoder->dcb->dpconf.link_nr,
 556                      nv_encoder->dcb->dpconf.link_bw);
 557
 558         if (nv_encoder->dcb->dpconf.link_nr < nv_encoder->dp.link_nr)
 559                 nv_encoder->dp.link_nr = nv_encoder->dcb->dpconf.link_nr;
 560         if (nv_encoder->dcb->dpconf.link_bw < nv_encoder->dp.link_bw)
 561                 nv_encoder->dp.link_bw = nv_encoder->dcb->dpconf.link_bw;
 562
 563         NV_DEBUG_KMS(dev, "maximum: %dx%d\n",
 564                      nv_encoder->dp.link_nr, nv_encoder->dp.link_bw);
 565
 566         nouveau_dp_probe_oui(dev, auxch, dpcd);
 567
 568         return true;
 569 }
 570
 571 int
 572 nouveau_dp_auxch(struct nouveau_i2c_chan *auxch, int cmd, int addr,
 573                  uint8_t *data, int data_nr)
 574 {
 575         return auxch_tx(auxch->dev, auxch->drive, cmd, addr, data, data_nr);
 576 }
 577
 578 static int
 579 nouveau_dp_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 580 {
 581         struct nouveau_i2c_chan *auxch = (struct nouveau_i2c_chan *)adap;
 582         struct i2c_msg *msg = msgs;
 583         int ret, mcnt = num;
 584
 585         while (mcnt--) {
 586                 u8 remaining = msg->len;
 587                 u8 *ptr = msg->buf;
 588
 589                 while (remaining) {
 590                         u8 cnt = (remaining > 16) ? 16 : remaining;
 591                         u8 cmd;
 592
 593                         if (msg->flags & I2C_M_RD)
 594                                 cmd = AUX_I2C_READ;
 595                         else
 596                                 cmd = AUX_I2C_WRITE;
 597
 598                         if (mcnt || remaining > 16)
 599                                 cmd |= AUX_I2C_MOT;
 600
 601                         ret = nouveau_dp_auxch(auxch, cmd, msg->addr, ptr, cnt);
 602                         if (ret < 0)
 603                                 return ret;
 604
 605                         ptr += cnt;
 606                         remaining -= cnt;
 607                 }
 608
 609                 msg++;
 610         }
 611
 612         return num;
 613 }
 614
 615 static u32
 616 nouveau_dp_i2c_func(struct i2c_adapter *adap)
 617 {
 618         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 619 }
 620
 621 const struct i2c_algorithm nouveau_dp_i2c_algo = {
 622         .master_xfer = nouveau_dp_i2c_xfer,
 623         .functionality = nouveau_dp_i2c_func
 624 };