drivers/gpu/drm/omapdrm/dss/dispc-compat.c

   1 /*
   2  * Copyright (C) 2012 Texas Instruments
   3  * Author: Tomi Valkeinen <[email protected]>
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 as published by
   7  * the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along with
  15  * this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #define DSS_SUBSYS_NAME "APPLY"
  19
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22 #include <linux/slab.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/jiffies.h>
  25 #include <linux/delay.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/seq_file.h>
  28
  29 #include <video/omapdss.h>
  30
  31 #include "dss.h"
  32 #include "dss_features.h"
  33 #include "dispc-compat.h"
  34
  35 #define DISPC_IRQ_MASK_ERROR            (DISPC_IRQ_GFX_FIFO_UNDERFLOW | \
  36                                          DISPC_IRQ_OCP_ERR | \
  37                                          DISPC_IRQ_VID1_FIFO_UNDERFLOW | \
  38                                          DISPC_IRQ_VID2_FIFO_UNDERFLOW | \
  39                                          DISPC_IRQ_SYNC_LOST | \
  40                                          DISPC_IRQ_SYNC_LOST_DIGIT)
  41
  42 #define DISPC_MAX_NR_ISRS               8
  43
  44 struct omap_dispc_isr_data {
  45         omap_dispc_isr_t        isr;
  46         void                    *arg;
  47         u32                     mask;
  48 };
  49
  50 struct dispc_irq_stats {
  51         unsigned long last_reset;
  52         unsigned irq_count;
  53         unsigned irqs[32];
  54 };
  55
  56 static struct {
  57         spinlock_t irq_lock;
  58         u32 irq_error_mask;
  59         struct omap_dispc_isr_data registered_isr[DISPC_MAX_NR_ISRS];
  60         u32 error_irqs;
  61         struct work_struct error_work;
  62
  63 #ifdef CONFIG_OMAP2_DSS_COLLECT_IRQ_STATS
  64         spinlock_t irq_stats_lock;
  65         struct dispc_irq_stats irq_stats;
  66 #endif
  67 } dispc_compat;
  68
  69
  70 #ifdef CONFIG_OMAP2_DSS_COLLECT_IRQ_STATS
  71 static void dispc_dump_irqs(struct seq_file *s)
  72 {
  73         unsigned long flags;
  74         struct dispc_irq_stats stats;
  75
  76         spin_lock_irqsave(&dispc_compat.irq_stats_lock, flags);
  77
  78         stats = dispc_compat.irq_stats;
  79         memset(&dispc_compat.irq_stats, 0, sizeof(dispc_compat.irq_stats));
  80         dispc_compat.irq_stats.last_reset = jiffies;
  81
  82         spin_unlock_irqrestore(&dispc_compat.irq_stats_lock, flags);
  83
  84         seq_printf(s, "period %u ms\n",
  85                         jiffies_to_msecs(jiffies - stats.last_reset));
  86
  87         seq_printf(s, "irqs %d\n", stats.irq_count);
  88 #define PIS(x) \
  89         seq_printf(s, "%-20s %10d\n", #x, stats.irqs[ffs(DISPC_IRQ_##x)-1]);
  90
  91         PIS(FRAMEDONE);
  92         PIS(VSYNC);
  93         PIS(EVSYNC_EVEN);
  94         PIS(EVSYNC_ODD);
  95         PIS(ACBIAS_COUNT_STAT);
  96         PIS(PROG_LINE_NUM);
  97         PIS(GFX_FIFO_UNDERFLOW);
  98         PIS(GFX_END_WIN);
  99         PIS(PAL_GAMMA_MASK);
 100         PIS(OCP_ERR);
 101         PIS(VID1_FIFO_UNDERFLOW);
 102         PIS(VID1_END_WIN);
 103         PIS(VID2_FIFO_UNDERFLOW);
 104         PIS(VID2_END_WIN);
 105         if (dss_feat_get_num_ovls() > 3) {
 106                 PIS(VID3_FIFO_UNDERFLOW);
 107                 PIS(VID3_END_WIN);
 108         }
 109         PIS(SYNC_LOST);
 110         PIS(SYNC_LOST_DIGIT);
 111         PIS(WAKEUP);
 112         if (dss_has_feature(FEAT_MGR_LCD2)) {
 113                 PIS(FRAMEDONE2);
 114                 PIS(VSYNC2);
 115                 PIS(ACBIAS_COUNT_STAT2);
 116                 PIS(SYNC_LOST2);
 117         }
 118         if (dss_has_feature(FEAT_MGR_LCD3)) {
 119                 PIS(FRAMEDONE3);
 120                 PIS(VSYNC3);
 121                 PIS(ACBIAS_COUNT_STAT3);
 122                 PIS(SYNC_LOST3);
 123         }
 124 #undef PIS
 125 }
 126 #endif
 127
 128 /* dispc.irq_lock has to be locked by the caller */
 129 static void _omap_dispc_set_irqs(void)
 130 {
 131         u32 mask;
 132         int i;
 133         struct omap_dispc_isr_data *isr_data;
 134
 135         mask = dispc_compat.irq_error_mask;
 136
 137         for (i = 0; i < DISPC_MAX_NR_ISRS; i++) {
 138                 isr_data = &dispc_compat.registered_isr[i];
 139
 140                 if (isr_data->isr == NULL)
 141                         continue;
 142
 143                 mask |= isr_data->mask;
 144         }
 145
 146         dispc_write_irqenable(mask);
 147 }
 148
 149 int omap_dispc_register_isr(omap_dispc_isr_t isr, void *arg, u32 mask)
 150 {
 151         int i;
 152         int ret;
 153         unsigned long flags;
 154         struct omap_dispc_isr_data *isr_data;
 155
 156         if (isr == NULL)
 157                 return -EINVAL;
 158
 159         spin_lock_irqsave(&dispc_compat.irq_lock, flags);
 160
 161         /* check for duplicate entry */
 162         for (i = 0; i < DISPC_MAX_NR_ISRS; i++) {
 163                 isr_data = &dispc_compat.registered_isr[i];
 164                 if (isr_data->isr == isr && isr_data->arg == arg &&
 165                                 isr_data->mask == mask) {
 166                         ret = -EINVAL;
 167                         goto err;
 168                 }
 169         }
 170
 171         isr_data = NULL;
 172         ret = -EBUSY;
 173
 174         for (i = 0; i < DISPC_MAX_NR_ISRS; i++) {
 175                 isr_data = &dispc_compat.registered_isr[i];
 176
 177                 if (isr_data->isr != NULL)
 178                         continue;
 179
 180                 isr_data->isr = isr;
 181                 isr_data->arg = arg;
 182                 isr_data->mask = mask;
 183                 ret = 0;
 184
 185                 break;
 186         }
 187
 188         if (ret)
 189                 goto err;
 190
 191         _omap_dispc_set_irqs();
 192
 193         spin_unlock_irqrestore(&dispc_compat.irq_lock, flags);
 194
 195         return 0;
 196 err:
 197         spin_unlock_irqrestore(&dispc_compat.irq_lock, flags);
 198
 199         return ret;
 200 }
 201 EXPORT_SYMBOL(omap_dispc_register_isr);
 202
 203 int omap_dispc_unregister_isr(omap_dispc_isr_t isr, void *arg, u32 mask)
 204 {
 205         int i;
 206         unsigned long flags;
 207         int ret = -EINVAL;
 208         struct omap_dispc_isr_data *isr_data;
 209
 210         spin_lock_irqsave(&dispc_compat.irq_lock, flags);
 211
 212         for (i = 0; i < DISPC_MAX_NR_ISRS; i++) {
 213                 isr_data = &dispc_compat.registered_isr[i];
 214                 if (isr_data->isr != isr || isr_data->arg != arg ||
 215                                 isr_data->mask != mask)
 216                         continue;
 217
 218                 /* found the correct isr */
 219
 220                 isr_data->isr = NULL;
 221                 isr_data->arg = NULL;
 222                 isr_data->mask = 0;
 223
 224                 ret = 0;
 225                 break;
 226         }
 227
 228         if (ret == 0)
 229                 _omap_dispc_set_irqs();
 230
 231         spin_unlock_irqrestore(&dispc_compat.irq_lock, flags);
 232
 233         return ret;
 234 }
 235 EXPORT_SYMBOL(omap_dispc_unregister_isr);
 236
 237 static void print_irq_status(u32 status)
 238 {
 239         if ((status & dispc_compat.irq_error_mask) == 0)
 240                 return;
 241
 242 #define PIS(x) (status & DISPC_IRQ_##x) ? (#x " ") : ""
 243
 244         pr_debug("DISPC IRQ: 0x%x: %s%s%s%s%s%s%s%s%s\n",
 245                 status,
 246                 PIS(OCP_ERR),
 247                 PIS(GFX_FIFO_UNDERFLOW),
 248                 PIS(VID1_FIFO_UNDERFLOW),
 249                 PIS(VID2_FIFO_UNDERFLOW),
 250                 dss_feat_get_num_ovls() > 3 ? PIS(VID3_FIFO_UNDERFLOW) : "",
 251                 PIS(SYNC_LOST),
 252                 PIS(SYNC_LOST_DIGIT),
 253                 dss_has_feature(FEAT_MGR_LCD2) ? PIS(SYNC_LOST2) : "",
 254                 dss_has_feature(FEAT_MGR_LCD3) ? PIS(SYNC_LOST3) : "");
 255 #undef PIS
 256 }
 257
 258 /* Called from dss.c. Note that we don't touch clocks here,
 259  * but we presume they are on because we got an IRQ. However,
 260  * an irq handler may turn the clocks off, so we may not have
 261  * clock later in the function. */
 262 static irqreturn_t omap_dispc_irq_handler(int irq, void *arg)
 263 {
 264         int i;
 265         u32 irqstatus, irqenable;
 266         u32 handledirqs = 0;
 267         u32 unhandled_errors;
 268         struct omap_dispc_isr_data *isr_data;
 269         struct omap_dispc_isr_data registered_isr[DISPC_MAX_NR_ISRS];
 270
 271         spin_lock(&dispc_compat.irq_lock);
 272
 273         irqstatus = dispc_read_irqstatus();
 274         irqenable = dispc_read_irqenable();
 275
 276         /* IRQ is not for us */
 277         if (!(irqstatus & irqenable)) {
 278                 spin_unlock(&dispc_compat.irq_lock);
 279                 return IRQ_NONE;
 280         }
 281
 282 #ifdef CONFIG_OMAP2_DSS_COLLECT_IRQ_STATS
 283         spin_lock(&dispc_compat.irq_stats_lock);
 284         dispc_compat.irq_stats.irq_count++;
 285         dss_collect_irq_stats(irqstatus, dispc_compat.irq_stats.irqs);
 286         spin_unlock(&dispc_compat.irq_stats_lock);
 287 #endif
 288
 289         print_irq_status(irqstatus);
 290
 291         /* Ack the interrupt. Do it here before clocks are possibly turned
 292          * off */
 293         dispc_clear_irqstatus(irqstatus);
 294         /* flush posted write */
 295         dispc_read_irqstatus();
 296
 297         /* make a copy and unlock, so that isrs can unregister
 298          * themselves */
 299         memcpy(registered_isr, dispc_compat.registered_isr,
 300                         sizeof(registered_isr));
 301
 302         spin_unlock(&dispc_compat.irq_lock);
 303
 304         for (i = 0; i < DISPC_MAX_NR_ISRS; i++) {
 305                 isr_data = &registered_isr[i];
 306
 307                 if (!isr_data->isr)
 308                         continue;
 309
 310                 if (isr_data->mask & irqstatus) {
 311                         isr_data->isr(isr_data->arg, irqstatus);
 312                         handledirqs |= isr_data->mask;
 313                 }
 314         }
 315
 316         spin_lock(&dispc_compat.irq_lock);
 317
 318         unhandled_errors = irqstatus & ~handledirqs & dispc_compat.irq_error_mask;
 319
 320         if (unhandled_errors) {
 321                 dispc_compat.error_irqs |= unhandled_errors;
 322
 323                 dispc_compat.irq_error_mask &= ~unhandled_errors;
 324                 _omap_dispc_set_irqs();
 325
 326                 schedule_work(&dispc_compat.error_work);
 327         }
 328
 329         spin_unlock(&dispc_compat.irq_lock);
 330
 331         return IRQ_HANDLED;
 332 }
 333
 334 static void dispc_error_worker(struct work_struct *work)
 335 {
 336         int i;
 337         u32 errors;
 338         unsigned long flags;
 339         static const unsigned fifo_underflow_bits[] = {
 340                 DISPC_IRQ_GFX_FIFO_UNDERFLOW,
 341                 DISPC_IRQ_VID1_FIFO_UNDERFLOW,
 342                 DISPC_IRQ_VID2_FIFO_UNDERFLOW,
 343                 DISPC_IRQ_VID3_FIFO_UNDERFLOW,
 344         };
 345
 346         spin_lock_irqsave(&dispc_compat.irq_lock, flags);
 347         errors = dispc_compat.error_irqs;
 348         dispc_compat.error_irqs = 0;
 349         spin_unlock_irqrestore(&dispc_compat.irq_lock, flags);
 350
 351         dispc_runtime_get();
 352
 353         for (i = 0; i < omap_dss_get_num_overlays(); ++i) {
 354                 struct omap_overlay *ovl;
 355                 unsigned bit;
 356
 357                 ovl = omap_dss_get_overlay(i);
 358                 bit = fifo_underflow_bits[i];
 359
 360                 if (bit & errors) {
 361                         DSSERR("FIFO UNDERFLOW on %s, disabling the overlay\n",
 362                                         ovl->name);
 363                         ovl->disable(ovl);
 364                         msleep(50);
 365                 }
 366         }
 367
 368         for (i = 0; i < omap_dss_get_num_overlay_managers(); ++i) {
 369                 struct omap_overlay_manager *mgr;
 370                 unsigned bit;
 371
 372                 mgr = omap_dss_get_overlay_manager(i);
 373                 bit = dispc_mgr_get_sync_lost_irq(i);
 374
 375                 if (bit & errors) {
 376                         int j;
 377
 378                         DSSERR("SYNC_LOST on channel %s, restarting the output "
 379                                         "with video overlays disabled\n",
 380                                         mgr->name);
 381
 382                         dss_mgr_disable(mgr);
 383
 384                         for (j = 0; j < omap_dss_get_num_overlays(); ++j) {
 385                                 struct omap_overlay *ovl;
 386                                 ovl = omap_dss_get_overlay(j);
 387
 388                                 if (ovl->id != OMAP_DSS_GFX &&
 389                                                 ovl->manager == mgr)
 390                                         ovl->disable(ovl);
 391                         }
 392
 393                         dss_mgr_enable(mgr);
 394                 }
 395         }
 396
 397         if (errors & DISPC_IRQ_OCP_ERR) {
 398                 DSSERR("OCP_ERR\n");
 399                 for (i = 0; i < omap_dss_get_num_overlay_managers(); ++i) {
 400                         struct omap_overlay_manager *mgr;
 401
 402                         mgr = omap_dss_get_overlay_manager(i);
 403                         dss_mgr_disable(mgr);
 404                 }
 405         }
 406
 407         spin_lock_irqsave(&dispc_compat.irq_lock, flags);
 408         dispc_compat.irq_error_mask |= errors;
 409         _omap_dispc_set_irqs();
 410         spin_unlock_irqrestore(&dispc_compat.irq_lock, flags);
 411
 412         dispc_runtime_put();
 413 }
 414
 415 int dss_dispc_initialize_irq(void)
 416 {
 417         int r;
 418
 419 #ifdef CONFIG_OMAP2_DSS_COLLECT_IRQ_STATS
 420         spin_lock_init(&dispc_compat.irq_stats_lock);
 421         dispc_compat.irq_stats.last_reset = jiffies;
 422         dss_debugfs_create_file("dispc_irq", dispc_dump_irqs);
 423 #endif
 424
 425         spin_lock_init(&dispc_compat.irq_lock);
 426
 427         memset(dispc_compat.registered_isr, 0,
 428                         sizeof(dispc_compat.registered_isr));
 429
 430         dispc_compat.irq_error_mask = DISPC_IRQ_MASK_ERROR;
 431         if (dss_has_feature(FEAT_MGR_LCD2))
 432                 dispc_compat.irq_error_mask |= DISPC_IRQ_SYNC_LOST2;
 433         if (dss_has_feature(FEAT_MGR_LCD3))
 434                 dispc_compat.irq_error_mask |= DISPC_IRQ_SYNC_LOST3;
 435         if (dss_feat_get_num_ovls() > 3)
 436                 dispc_compat.irq_error_mask |= DISPC_IRQ_VID3_FIFO_UNDERFLOW;
 437
 438         /*
 439          * there's SYNC_LOST_DIGIT waiting after enabling the DSS,
 440          * so clear it
 441          */
 442         dispc_clear_irqstatus(dispc_read_irqstatus());
 443
 444         INIT_WORK(&dispc_compat.error_work, dispc_error_worker);
 445
 446         _omap_dispc_set_irqs();
 447
 448         r = dispc_request_irq(omap_dispc_irq_handler, &dispc_compat);
 449         if (r) {
 450                 DSSERR("dispc_request_irq failed\n");
 451                 return r;
 452         }
 453
 454         return 0;
 455 }
 456
 457 void dss_dispc_uninitialize_irq(void)
 458 {
 459         dispc_free_irq(&dispc_compat);
 460 }
 461
 462 static void dispc_mgr_disable_isr(void *data, u32 mask)
 463 {
 464         struct completion *compl = data;
 465         complete(compl);
 466 }
 467
 468 static void dispc_mgr_enable_lcd_out(enum omap_channel channel)
 469 {
 470         dispc_mgr_enable(channel, true);
 471 }
 472
 473 static void dispc_mgr_disable_lcd_out(enum omap_channel channel)
 474 {
 475         DECLARE_COMPLETION_ONSTACK(framedone_compl);
 476         int r;
 477         u32 irq;
 478
 479         if (!dispc_mgr_is_enabled(channel))
 480                 return;
 481
 482         /*
 483          * When we disable LCD output, we need to wait for FRAMEDONE to know
 484          * that DISPC has finished with the LCD output.
 485          */
 486
 487         irq = dispc_mgr_get_framedone_irq(channel);
 488
 489         r = omap_dispc_register_isr(dispc_mgr_disable_isr, &framedone_compl,
 490                         irq);
 491         if (r)
 492                 DSSERR("failed to register FRAMEDONE isr\n");
 493
 494         dispc_mgr_enable(channel, false);
 495
 496         /* if we couldn't register for framedone, just sleep and exit */
 497         if (r) {
 498                 msleep(100);
 499                 return;
 500         }
 501
 502         if (!wait_for_completion_timeout(&framedone_compl,
 503                                 msecs_to_jiffies(100)))
 504                 DSSERR("timeout waiting for FRAME DONE\n");
 505
 506         r = omap_dispc_unregister_isr(dispc_mgr_disable_isr, &framedone_compl,
 507                         irq);
 508         if (r)
 509                 DSSERR("failed to unregister FRAMEDONE isr\n");
 510 }
 511
 512 static void dispc_digit_out_enable_isr(void *data, u32 mask)
 513 {
 514         struct completion *compl = data;
 515
 516         /* ignore any sync lost interrupts */
 517         if (mask & (DISPC_IRQ_EVSYNC_EVEN | DISPC_IRQ_EVSYNC_ODD))
 518                 complete(compl);
 519 }
 520
 521 static void dispc_mgr_enable_digit_out(void)
 522 {
 523         DECLARE_COMPLETION_ONSTACK(vsync_compl);
 524         int r;
 525         u32 irq_mask;
 526
 527         if (dispc_mgr_is_enabled(OMAP_DSS_CHANNEL_DIGIT))
 528                 return;
 529
 530         /*
 531          * Digit output produces some sync lost interrupts during the first
 532          * frame when enabling. Those need to be ignored, so we register for the
 533          * sync lost irq to prevent the error handler from triggering.
 534          */
 535
 536         irq_mask = dispc_mgr_get_vsync_irq(OMAP_DSS_CHANNEL_DIGIT) |
 537                 dispc_mgr_get_sync_lost_irq(OMAP_DSS_CHANNEL_DIGIT);
 538
 539         r = omap_dispc_register_isr(dispc_digit_out_enable_isr, &vsync_compl,
 540                         irq_mask);
 541         if (r) {
 542                 DSSERR("failed to register %x isr\n", irq_mask);
 543                 return;
 544         }
 545
 546         dispc_mgr_enable(OMAP_DSS_CHANNEL_DIGIT, true);
 547
 548         /* wait for the first evsync */
 549         if (!wait_for_completion_timeout(&vsync_compl, msecs_to_jiffies(100)))
 550                 DSSERR("timeout waiting for digit out to start\n");
 551
 552         r = omap_dispc_unregister_isr(dispc_digit_out_enable_isr, &vsync_compl,
 553                         irq_mask);
 554         if (r)
 555                 DSSERR("failed to unregister %x isr\n", irq_mask);
 556 }
 557
 558 static void dispc_mgr_disable_digit_out(void)
 559 {
 560         DECLARE_COMPLETION_ONSTACK(framedone_compl);
 561         int r, i;
 562         u32 irq_mask;
 563         int num_irqs;
 564
 565         if (!dispc_mgr_is_enabled(OMAP_DSS_CHANNEL_DIGIT))
 566                 return;
 567
 568         /*
 569          * When we disable the digit output, we need to wait for FRAMEDONE to
 570          * know that DISPC has finished with the output.
 571          */
 572
 573         irq_mask = dispc_mgr_get_framedone_irq(OMAP_DSS_CHANNEL_DIGIT);
 574         num_irqs = 1;
 575
 576         if (!irq_mask) {
 577                 /*
 578                  * omap 2/3 don't have framedone irq for TV, so we need to use
 579                  * vsyncs for this.
 580                  */
 581
 582                 irq_mask = dispc_mgr_get_vsync_irq(OMAP_DSS_CHANNEL_DIGIT);
 583                 /*
 584                  * We need to wait for both even and odd vsyncs. Note that this
 585                  * is not totally reliable, as we could get a vsync interrupt
 586                  * before we disable the output, which leads to timeout in the
 587                  * wait_for_completion.
 588                  */
 589                 num_irqs = 2;
 590         }
 591
 592         r = omap_dispc_register_isr(dispc_mgr_disable_isr, &framedone_compl,
 593                         irq_mask);
 594         if (r)
 595                 DSSERR("failed to register %x isr\n", irq_mask);
 596
 597         dispc_mgr_enable(OMAP_DSS_CHANNEL_DIGIT, false);
 598
 599         /* if we couldn't register the irq, just sleep and exit */
 600         if (r) {
 601                 msleep(100);
 602                 return;
 603         }
 604
 605         for (i = 0; i < num_irqs; ++i) {
 606                 if (!wait_for_completion_timeout(&framedone_compl,
 607                                         msecs_to_jiffies(100)))
 608                         DSSERR("timeout waiting for digit out to stop\n");
 609         }
 610
 611         r = omap_dispc_unregister_isr(dispc_mgr_disable_isr, &framedone_compl,
 612                         irq_mask);
 613         if (r)
 614                 DSSERR("failed to unregister %x isr\n", irq_mask);
 615 }
 616
 617 void dispc_mgr_enable_sync(enum omap_channel channel)
 618 {
 619         if (dss_mgr_is_lcd(channel))
 620                 dispc_mgr_enable_lcd_out(channel);
 621         else if (channel == OMAP_DSS_CHANNEL_DIGIT)
 622                 dispc_mgr_enable_digit_out();
 623         else
 624                 WARN_ON(1);
 625 }
 626
 627 void dispc_mgr_disable_sync(enum omap_channel channel)
 628 {
 629         if (dss_mgr_is_lcd(channel))
 630                 dispc_mgr_disable_lcd_out(channel);
 631         else if (channel == OMAP_DSS_CHANNEL_DIGIT)
 632                 dispc_mgr_disable_digit_out();
 633         else
 634                 WARN_ON(1);
 635 }
 636
 637 static inline void dispc_irq_wait_handler(void *data, u32 mask)
 638 {
 639         complete((struct completion *)data);
 640 }
 641
 642 int omap_dispc_wait_for_irq_interruptible_timeout(u32 irqmask,
 643                 unsigned long timeout)
 644 {
 645
 646         int r;
 647         DECLARE_COMPLETION_ONSTACK(completion);
 648
 649         r = omap_dispc_register_isr(dispc_irq_wait_handler, &completion,
 650                         irqmask);
 651
 652         if (r)
 653                 return r;
 654
 655         timeout = wait_for_completion_interruptible_timeout(&completion,
 656                         timeout);
 657
 658         omap_dispc_unregister_isr(dispc_irq_wait_handler, &completion, irqmask);
 659
 660         if (timeout == 0)
 661                 return -ETIMEDOUT;
 662
 663         if (timeout == -ERESTARTSYS)
 664                 return -ERESTARTSYS;
 665
 666         return 0;
 667 }