drivers/gpu/host1x/syncpt.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Tegra host1x Syncpoints
   4  *
   5  * Copyright (c) 2010-2015, NVIDIA Corporation.
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/device.h>
  10 #include <linux/slab.h>
  11
  12 #include <trace/events/host1x.h>
  13
  14 #include "syncpt.h"
  15 #include "dev.h"
  16 #include "intr.h"
  17 #include "debug.h"
  18
  19 #define SYNCPT_CHECK_PERIOD (2 * HZ)
  20 #define MAX_STUCK_CHECK_COUNT 15
  21
  22 static struct host1x_syncpt_base *
  23 host1x_syncpt_base_request(struct host1x *host)
  24 {
  25         struct host1x_syncpt_base *bases = host->bases;
  26         unsigned int i;
  27
  28         for (i = 0; i < host->info->nb_bases; i++)
  29                 if (!bases[i].requested)
  30                         break;
  31
  32         if (i >= host->info->nb_bases)
  33                 return NULL;
  34
  35         bases[i].requested = true;
  36         return &bases[i];
  37 }
  38
  39 static void host1x_syncpt_base_free(struct host1x_syncpt_base *base)
  40 {
  41         if (base)
  42                 base->requested = false;
  43 }
  44
  45 /**
  46  * host1x_syncpt_alloc() - allocate a syncpoint
  47  * @host: host1x device data
  48  * @flags: bitfield of HOST1X_SYNCPT_* flags
  49  * @name: name for the syncpoint for use in debug prints
  50  *
  51  * Allocates a hardware syncpoint for the caller's use. The caller then has
  52  * the sole authority to mutate the syncpoint's value until it is freed again.
  53  *
  54  * If no free syncpoints are available, or a NULL name was specified, returns
  55  * NULL.
  56  */
  57 struct host1x_syncpt *host1x_syncpt_alloc(struct host1x *host,
  58                                           unsigned long flags,
  59                                           const char *name)
  60 {
  61         struct host1x_syncpt *sp = host->syncpt;
  62         char *full_name;
  63         unsigned int i;
  64
  65         if (!name)
  66                 return NULL;
  67
  68         mutex_lock(&host->syncpt_mutex);
  69
  70         for (i = 0; i < host->info->nb_pts && kref_read(&sp->ref); i++, sp++)
  71                 ;
  72
  73         if (i >= host->info->nb_pts)
  74                 goto unlock;
  75
  76         if (flags & HOST1X_SYNCPT_HAS_BASE) {
  77                 sp->base = host1x_syncpt_base_request(host);
  78                 if (!sp->base)
  79                         goto unlock;
  80         }
  81
  82         full_name = kasprintf(GFP_KERNEL, "%u-%s", sp->id, name);
  83         if (!full_name)
  84                 goto free_base;
  85
  86         sp->name = full_name;
  87
  88         if (flags & HOST1X_SYNCPT_CLIENT_MANAGED)
  89                 sp->client_managed = true;
  90         else
  91                 sp->client_managed = false;
  92
  93         kref_init(&sp->ref);
  94
  95         mutex_unlock(&host->syncpt_mutex);
  96         return sp;
  97
  98 free_base:
  99         host1x_syncpt_base_free(sp->base);
 100         sp->base = NULL;
 101 unlock:
 102         mutex_unlock(&host->syncpt_mutex);
 103         return NULL;
 104 }
 105 EXPORT_SYMBOL(host1x_syncpt_alloc);
 106
 107 /**
 108  * host1x_syncpt_id() - retrieve syncpoint ID
 109  * @sp: host1x syncpoint
 110  *
 111  * Given a pointer to a struct host1x_syncpt, retrieves its ID. This ID is
 112  * often used as a value to program into registers that control how hardware
 113  * blocks interact with syncpoints.
 114  */
 115 u32 host1x_syncpt_id(struct host1x_syncpt *sp)
 116 {
 117         return sp->id;
 118 }
 119 EXPORT_SYMBOL(host1x_syncpt_id);
 120
 121 /**
 122  * host1x_syncpt_incr_max() - update the value sent to hardware
 123  * @sp: host1x syncpoint
 124  * @incrs: number of increments
 125  */
 126 u32 host1x_syncpt_incr_max(struct host1x_syncpt *sp, u32 incrs)
 127 {
 128         return (u32)atomic_add_return(incrs, &sp->max_val);
 129 }
 130 EXPORT_SYMBOL(host1x_syncpt_incr_max);
 131
 132  /*
 133  * Write cached syncpoint and waitbase values to hardware.
 134  */
 135 void host1x_syncpt_restore(struct host1x *host)
 136 {
 137         struct host1x_syncpt *sp_base = host->syncpt;
 138         unsigned int i;
 139
 140         for (i = 0; i < host1x_syncpt_nb_pts(host); i++)
 141                 host1x_hw_syncpt_restore(host, sp_base + i);
 142
 143         for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
 144                 host1x_hw_syncpt_restore_wait_base(host, sp_base + i);
 145
 146         wmb();
 147 }
 148
 149 /*
 150  * Update the cached syncpoint and waitbase values by reading them
 151  * from the registers.
 152   */
 153 void host1x_syncpt_save(struct host1x *host)
 154 {
 155         struct host1x_syncpt *sp_base = host->syncpt;
 156         unsigned int i;
 157
 158         for (i = 0; i < host1x_syncpt_nb_pts(host); i++) {
 159                 if (host1x_syncpt_client_managed(sp_base + i))
 160                         host1x_hw_syncpt_load(host, sp_base + i);
 161                 else
 162                         WARN_ON(!host1x_syncpt_idle(sp_base + i));
 163         }
 164
 165         for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
 166                 host1x_hw_syncpt_load_wait_base(host, sp_base + i);
 167 }
 168
 169 /*
 170  * Updates the cached syncpoint value by reading a new value from the hardware
 171  * register
 172  */
 173 u32 host1x_syncpt_load(struct host1x_syncpt *sp)
 174 {
 175         u32 val;
 176
 177         val = host1x_hw_syncpt_load(sp->host, sp);
 178         trace_host1x_syncpt_load_min(sp->id, val);
 179
 180         return val;
 181 }
 182
 183 /*
 184  * Get the current syncpoint base
 185  */
 186 u32 host1x_syncpt_load_wait_base(struct host1x_syncpt *sp)
 187 {
 188         host1x_hw_syncpt_load_wait_base(sp->host, sp);
 189
 190         return sp->base_val;
 191 }
 192
 193 /**
 194  * host1x_syncpt_incr() - increment syncpoint value from CPU, updating cache
 195  * @sp: host1x syncpoint
 196  */
 197 int host1x_syncpt_incr(struct host1x_syncpt *sp)
 198 {
 199         return host1x_hw_syncpt_cpu_incr(sp->host, sp);
 200 }
 201 EXPORT_SYMBOL(host1x_syncpt_incr);
 202
 203 /*
 204  * Updated sync point form hardware, and returns true if syncpoint is expired,
 205  * false if we may need to wait
 206  */
 207 static bool syncpt_load_min_is_expired(struct host1x_syncpt *sp, u32 thresh)
 208 {
 209         host1x_hw_syncpt_load(sp->host, sp);
 210
 211         return host1x_syncpt_is_expired(sp, thresh);
 212 }
 213
 214 /**
 215  * host1x_syncpt_wait() - wait for a syncpoint to reach a given value
 216  * @sp: host1x syncpoint
 217  * @thresh: threshold
 218  * @timeout: maximum time to wait for the syncpoint to reach the given value
 219  * @value: return location for the syncpoint value
 220  */
 221 int host1x_syncpt_wait(struct host1x_syncpt *sp, u32 thresh, long timeout,
 222                        u32 *value)
 223 {
 224         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
 225         void *ref;
 226         struct host1x_waitlist *waiter;
 227         int err = 0, check_count = 0;
 228         u32 val;
 229
 230         if (value)
 231                 *value = 0;
 232
 233         /* first check cache */
 234         if (host1x_syncpt_is_expired(sp, thresh)) {
 235                 if (value)
 236                         *value = host1x_syncpt_load(sp);
 237
 238                 return 0;
 239         }
 240
 241         /* try to read from register */
 242         val = host1x_hw_syncpt_load(sp->host, sp);
 243         if (host1x_syncpt_is_expired(sp, thresh)) {
 244                 if (value)
 245                         *value = val;
 246
 247                 goto done;
 248         }
 249
 250         if (!timeout) {
 251                 err = -EAGAIN;
 252                 goto done;
 253         }
 254
 255         /* allocate a waiter */
 256         waiter = kzalloc(sizeof(*waiter), GFP_KERNEL);
 257         if (!waiter) {
 258                 err = -ENOMEM;
 259                 goto done;
 260         }
 261
 262         /* schedule a wakeup when the syncpoint value is reached */
 263         err = host1x_intr_add_action(sp->host, sp, thresh,
 264                                      HOST1X_INTR_ACTION_WAKEUP_INTERRUPTIBLE,
 265                                      &wq, waiter, &ref);
 266         if (err)
 267                 goto done;
 268
 269         err = -EAGAIN;
 270         /* Caller-specified timeout may be impractically low */
 271         if (timeout < 0)
 272                 timeout = LONG_MAX;
 273
 274         /* wait for the syncpoint, or timeout, or signal */
 275         while (timeout) {
 276                 long check = min_t(long, SYNCPT_CHECK_PERIOD, timeout);
 277                 int remain;
 278
 279                 remain = wait_event_interruptible_timeout(wq,
 280                                 syncpt_load_min_is_expired(sp, thresh),
 281                                 check);
 282                 if (remain > 0 || host1x_syncpt_is_expired(sp, thresh)) {
 283                         if (value)
 284                                 *value = host1x_syncpt_load(sp);
 285
 286                         err = 0;
 287
 288                         break;
 289                 }
 290
 291                 if (remain < 0) {
 292                         err = remain;
 293                         break;
 294                 }
 295
 296                 timeout -= check;
 297
 298                 if (timeout && check_count <= MAX_STUCK_CHECK_COUNT) {
 299                         dev_warn(sp->host->dev,
 300                                 "%s: syncpoint id %u (%s) stuck waiting %d, timeout=%ld\n",
 301                                  current->comm, sp->id, sp->name,
 302                                  thresh, timeout);
 303
 304                         host1x_debug_dump_syncpts(sp->host);
 305
 306                         if (check_count == MAX_STUCK_CHECK_COUNT)
 307                                 host1x_debug_dump(sp->host);
 308
 309                         check_count++;
 310                 }
 311         }
 312
 313         host1x_intr_put_ref(sp->host, sp->id, ref, true);
 314
 315 done:
 316         return err;
 317 }
 318 EXPORT_SYMBOL(host1x_syncpt_wait);
 319
 320 /*
 321  * Returns true if syncpoint is expired, false if we may need to wait
 322  */
 323 bool host1x_syncpt_is_expired(struct host1x_syncpt *sp, u32 thresh)
 324 {
 325         u32 current_val;
 326
 327         smp_rmb();
 328
 329         current_val = (u32)atomic_read(&sp->min_val);
 330
 331         return ((current_val - thresh) & 0x80000000U) == 0U;
 332 }
 333
 334 int host1x_syncpt_init(struct host1x *host)
 335 {
 336         struct host1x_syncpt_base *bases;
 337         struct host1x_syncpt *syncpt;
 338         unsigned int i;
 339
 340         syncpt = devm_kcalloc(host->dev, host->info->nb_pts, sizeof(*syncpt),
 341                               GFP_KERNEL);
 342         if (!syncpt)
 343                 return -ENOMEM;
 344
 345         bases = devm_kcalloc(host->dev, host->info->nb_bases, sizeof(*bases),
 346                              GFP_KERNEL);
 347         if (!bases)
 348                 return -ENOMEM;
 349
 350         for (i = 0; i < host->info->nb_pts; i++) {
 351                 syncpt[i].id = i;
 352                 syncpt[i].host = host;
 353
 354                 /*
 355                  * Unassign syncpt from channels for purposes of Tegra186
 356                  * syncpoint protection. This prevents any channel from
 357                  * accessing it until it is reassigned.
 358                  */
 359                 host1x_hw_syncpt_assign_to_channel(host, &syncpt[i], NULL);
 360         }
 361
 362         for (i = 0; i < host->info->nb_bases; i++)
 363                 bases[i].id = i;
 364
 365         mutex_init(&host->syncpt_mutex);
 366         host->syncpt = syncpt;
 367         host->bases = bases;
 368
 369         host1x_syncpt_restore(host);
 370         host1x_hw_syncpt_enable_protection(host);
 371
 372         /* Allocate sync point to use for clearing waits for expired fences */
 373         host->nop_sp = host1x_syncpt_alloc(host, 0, "reserved-nop");
 374         if (!host->nop_sp)
 375                 return -ENOMEM;
 376
 377         if (host->info->reserve_vblank_syncpts) {
 378                 kref_init(&host->syncpt[26].ref);
 379                 kref_init(&host->syncpt[27].ref);
 380         }
 381
 382         return 0;
 383 }
 384
 385 /**
 386  * host1x_syncpt_request() - request a syncpoint
 387  * @client: client requesting the syncpoint
 388  * @flags: flags
 389  *
 390  * host1x client drivers can use this function to allocate a syncpoint for
 391  * subsequent use. A syncpoint returned by this function will be reserved for
 392  * use by the client exclusively. When no longer using a syncpoint, a host1x
 393  * client driver needs to release it using host1x_syncpt_put().
 394  */
 395 struct host1x_syncpt *host1x_syncpt_request(struct host1x_client *client,
 396                                             unsigned long flags)
 397 {
 398         struct host1x *host = dev_get_drvdata(client->host->parent);
 399
 400         return host1x_syncpt_alloc(host, flags, dev_name(client->dev));
 401 }
 402 EXPORT_SYMBOL(host1x_syncpt_request);
 403
 404 static void syncpt_release(struct kref *ref)
 405 {
 406         struct host1x_syncpt *sp = container_of(ref, struct host1x_syncpt, ref);
 407
 408         atomic_set(&sp->max_val, host1x_syncpt_read(sp));
 409
 410         sp->locked = false;
 411
 412         mutex_lock(&sp->host->syncpt_mutex);
 413
 414         host1x_syncpt_base_free(sp->base);
 415         kfree(sp->name);
 416         sp->base = NULL;
 417         sp->name = NULL;
 418         sp->client_managed = false;
 419
 420         mutex_unlock(&sp->host->syncpt_mutex);
 421 }
 422
 423 /**
 424  * host1x_syncpt_put() - free a requested syncpoint
 425  * @sp: host1x syncpoint
 426  *
 427  * Release a syncpoint previously allocated using host1x_syncpt_request(). A
 428  * host1x client driver should call this when the syncpoint is no longer in
 429  * use.
 430  */
 431 void host1x_syncpt_put(struct host1x_syncpt *sp)
 432 {
 433         if (!sp)
 434                 return;
 435
 436         kref_put(&sp->ref, syncpt_release);
 437 }
 438 EXPORT_SYMBOL(host1x_syncpt_put);
 439
 440 void host1x_syncpt_deinit(struct host1x *host)
 441 {
 442         struct host1x_syncpt *sp = host->syncpt;
 443         unsigned int i;
 444
 445         for (i = 0; i < host->info->nb_pts; i++, sp++)
 446                 kfree(sp->name);
 447 }
 448
 449 /**
 450  * host1x_syncpt_read_max() - read maximum syncpoint value
 451  * @sp: host1x syncpoint
 452  *
 453  * The maximum syncpoint value indicates how many operations there are in
 454  * queue, either in channel or in a software thread.
 455  */
 456 u32 host1x_syncpt_read_max(struct host1x_syncpt *sp)
 457 {
 458         smp_rmb();
 459
 460         return (u32)atomic_read(&sp->max_val);
 461 }
 462 EXPORT_SYMBOL(host1x_syncpt_read_max);
 463
 464 /**
 465  * host1x_syncpt_read_min() - read minimum syncpoint value
 466  * @sp: host1x syncpoint
 467  *
 468  * The minimum syncpoint value is a shadow of the current sync point value in
 469  * hardware.
 470  */
 471 u32 host1x_syncpt_read_min(struct host1x_syncpt *sp)
 472 {
 473         smp_rmb();
 474
 475         return (u32)atomic_read(&sp->min_val);
 476 }
 477 EXPORT_SYMBOL(host1x_syncpt_read_min);
 478
 479 /**
 480  * host1x_syncpt_read() - read the current syncpoint value
 481  * @sp: host1x syncpoint
 482  */
 483 u32 host1x_syncpt_read(struct host1x_syncpt *sp)
 484 {
 485         return host1x_syncpt_load(sp);
 486 }
 487 EXPORT_SYMBOL(host1x_syncpt_read);
 488
 489 unsigned int host1x_syncpt_nb_pts(struct host1x *host)
 490 {
 491         return host->info->nb_pts;
 492 }
 493
 494 unsigned int host1x_syncpt_nb_bases(struct host1x *host)
 495 {
 496         return host->info->nb_bases;
 497 }
 498
 499 unsigned int host1x_syncpt_nb_mlocks(struct host1x *host)
 500 {
 501         return host->info->nb_mlocks;
 502 }
 503
 504 /**
 505  * host1x_syncpt_get_by_id() - obtain a syncpoint by ID
 506  * @host: host1x controller
 507  * @id: syncpoint ID
 508  */
 509 struct host1x_syncpt *host1x_syncpt_get_by_id(struct host1x *host,
 510                                               unsigned int id)
 511 {
 512         if (id >= host->info->nb_pts)
 513                 return NULL;
 514
 515         if (kref_get_unless_zero(&host->syncpt[id].ref))
 516                 return &host->syncpt[id];
 517         else
 518                 return NULL;
 519 }
 520 EXPORT_SYMBOL(host1x_syncpt_get_by_id);
 521
 522 /**
 523  * host1x_syncpt_get_by_id_noref() - obtain a syncpoint by ID but don't
 524  *      increase the refcount.
 525  * @host: host1x controller
 526  * @id: syncpoint ID
 527  */
 528 struct host1x_syncpt *host1x_syncpt_get_by_id_noref(struct host1x *host,
 529                                                     unsigned int id)
 530 {
 531         if (id >= host->info->nb_pts)
 532                 return NULL;
 533
 534         return &host->syncpt[id];
 535 }
 536 EXPORT_SYMBOL(host1x_syncpt_get_by_id_noref);
 537
 538 /**
 539  * host1x_syncpt_get() - increment syncpoint refcount
 540  * @sp: syncpoint
 541  */
 542 struct host1x_syncpt *host1x_syncpt_get(struct host1x_syncpt *sp)
 543 {
 544         kref_get(&sp->ref);
 545
 546         return sp;
 547 }
 548 EXPORT_SYMBOL(host1x_syncpt_get);
 549
 550 /**
 551  * host1x_syncpt_get_base() - obtain the wait base associated with a syncpoint
 552  * @sp: host1x syncpoint
 553  */
 554 struct host1x_syncpt_base *host1x_syncpt_get_base(struct host1x_syncpt *sp)
 555 {
 556         return sp ? sp->base : NULL;
 557 }
 558 EXPORT_SYMBOL(host1x_syncpt_get_base);
 559
 560 /**
 561  * host1x_syncpt_base_id() - retrieve the ID of a syncpoint wait base
 562  * @base: host1x syncpoint wait base
 563  */
 564 u32 host1x_syncpt_base_id(struct host1x_syncpt_base *base)
 565 {
 566         return base->id;
 567 }
 568 EXPORT_SYMBOL(host1x_syncpt_base_id);
 569
 570 static void do_nothing(struct kref *ref)
 571 {
 572 }
 573
 574 /**
 575  * host1x_syncpt_release_vblank_reservation() - Make VBLANK syncpoint
 576  *   available for allocation
 577  *
 578  * @client: host1x bus client
 579  * @syncpt_id: syncpoint ID to make available
 580  *
 581  * Makes VBLANK<i> syncpoint available for allocatation if it was
 582  * reserved at initialization time. This should be called by the display
 583  * driver after it has ensured that any VBLANK increment programming configured
 584  * by the boot chain has been disabled.
 585  */
 586 void host1x_syncpt_release_vblank_reservation(struct host1x_client *client,
 587                                               u32 syncpt_id)
 588 {
 589         struct host1x *host = dev_get_drvdata(client->host->parent);
 590
 591         if (!host->info->reserve_vblank_syncpts)
 592                 return;
 593
 594         kref_put(&host->syncpt[syncpt_id].ref, do_nothing);
 595 }
 596 EXPORT_SYMBOL(host1x_syncpt_release_vblank_reservation);