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 && sp->name; 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         mutex_unlock(&host->syncpt_mutex);
  94         return sp;
  95
  96 free_base:
  97         host1x_syncpt_base_free(sp->base);
  98         sp->base = NULL;
  99 unlock:
 100         mutex_unlock(&host->syncpt_mutex);
 101         return NULL;
 102 }
 103 EXPORT_SYMBOL(host1x_syncpt_alloc);
 104
 105 /**
 106  * host1x_syncpt_id() - retrieve syncpoint ID
 107  * @sp: host1x syncpoint
 108  *
 109  * Given a pointer to a struct host1x_syncpt, retrieves its ID. This ID is
 110  * often used as a value to program into registers that control how hardware
 111  * blocks interact with syncpoints.
 112  */
 113 u32 host1x_syncpt_id(struct host1x_syncpt *sp)
 114 {
 115         return sp->id;
 116 }
 117 EXPORT_SYMBOL(host1x_syncpt_id);
 118
 119 /**
 120  * host1x_syncpt_incr_max() - update the value sent to hardware
 121  * @sp: host1x syncpoint
 122  * @incrs: number of increments
 123  */
 124 u32 host1x_syncpt_incr_max(struct host1x_syncpt *sp, u32 incrs)
 125 {
 126         return (u32)atomic_add_return(incrs, &sp->max_val);
 127 }
 128 EXPORT_SYMBOL(host1x_syncpt_incr_max);
 129
 130  /*
 131  * Write cached syncpoint and waitbase values to hardware.
 132  */
 133 void host1x_syncpt_restore(struct host1x *host)
 134 {
 135         struct host1x_syncpt *sp_base = host->syncpt;
 136         unsigned int i;
 137
 138         for (i = 0; i < host1x_syncpt_nb_pts(host); i++)
 139                 host1x_hw_syncpt_restore(host, sp_base + i);
 140
 141         for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
 142                 host1x_hw_syncpt_restore_wait_base(host, sp_base + i);
 143
 144         wmb();
 145 }
 146
 147 /*
 148  * Update the cached syncpoint and waitbase values by reading them
 149  * from the registers.
 150   */
 151 void host1x_syncpt_save(struct host1x *host)
 152 {
 153         struct host1x_syncpt *sp_base = host->syncpt;
 154         unsigned int i;
 155
 156         for (i = 0; i < host1x_syncpt_nb_pts(host); i++) {
 157                 if (host1x_syncpt_client_managed(sp_base + i))
 158                         host1x_hw_syncpt_load(host, sp_base + i);
 159                 else
 160                         WARN_ON(!host1x_syncpt_idle(sp_base + i));
 161         }
 162
 163         for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
 164                 host1x_hw_syncpt_load_wait_base(host, sp_base + i);
 165 }
 166
 167 /*
 168  * Updates the cached syncpoint value by reading a new value from the hardware
 169  * register
 170  */
 171 u32 host1x_syncpt_load(struct host1x_syncpt *sp)
 172 {
 173         u32 val;
 174
 175         val = host1x_hw_syncpt_load(sp->host, sp);
 176         trace_host1x_syncpt_load_min(sp->id, val);
 177
 178         return val;
 179 }
 180
 181 /*
 182  * Get the current syncpoint base
 183  */
 184 u32 host1x_syncpt_load_wait_base(struct host1x_syncpt *sp)
 185 {
 186         host1x_hw_syncpt_load_wait_base(sp->host, sp);
 187
 188         return sp->base_val;
 189 }
 190
 191 /**
 192  * host1x_syncpt_incr() - increment syncpoint value from CPU, updating cache
 193  * @sp: host1x syncpoint
 194  */
 195 int host1x_syncpt_incr(struct host1x_syncpt *sp)
 196 {
 197         return host1x_hw_syncpt_cpu_incr(sp->host, sp);
 198 }
 199 EXPORT_SYMBOL(host1x_syncpt_incr);
 200
 201 /*
 202  * Updated sync point form hardware, and returns true if syncpoint is expired,
 203  * false if we may need to wait
 204  */
 205 static bool syncpt_load_min_is_expired(struct host1x_syncpt *sp, u32 thresh)
 206 {
 207         host1x_hw_syncpt_load(sp->host, sp);
 208
 209         return host1x_syncpt_is_expired(sp, thresh);
 210 }
 211
 212 /**
 213  * host1x_syncpt_wait() - wait for a syncpoint to reach a given value
 214  * @sp: host1x syncpoint
 215  * @thresh: threshold
 216  * @timeout: maximum time to wait for the syncpoint to reach the given value
 217  * @value: return location for the syncpoint value
 218  */
 219 int host1x_syncpt_wait(struct host1x_syncpt *sp, u32 thresh, long timeout,
 220                        u32 *value)
 221 {
 222         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
 223         void *ref;
 224         struct host1x_waitlist *waiter;
 225         int err = 0, check_count = 0;
 226         u32 val;
 227
 228         if (value)
 229                 *value = 0;
 230
 231         /* first check cache */
 232         if (host1x_syncpt_is_expired(sp, thresh)) {
 233                 if (value)
 234                         *value = host1x_syncpt_load(sp);
 235
 236                 return 0;
 237         }
 238
 239         /* try to read from register */
 240         val = host1x_hw_syncpt_load(sp->host, sp);
 241         if (host1x_syncpt_is_expired(sp, thresh)) {
 242                 if (value)
 243                         *value = val;
 244
 245                 goto done;
 246         }
 247
 248         if (!timeout) {
 249                 err = -EAGAIN;
 250                 goto done;
 251         }
 252
 253         /* allocate a waiter */
 254         waiter = kzalloc(sizeof(*waiter), GFP_KERNEL);
 255         if (!waiter) {
 256                 err = -ENOMEM;
 257                 goto done;
 258         }
 259
 260         /* schedule a wakeup when the syncpoint value is reached */
 261         err = host1x_intr_add_action(sp->host, sp, thresh,
 262                                      HOST1X_INTR_ACTION_WAKEUP_INTERRUPTIBLE,
 263                                      &wq, waiter, &ref);
 264         if (err)
 265                 goto done;
 266
 267         err = -EAGAIN;
 268         /* Caller-specified timeout may be impractically low */
 269         if (timeout < 0)
 270                 timeout = LONG_MAX;
 271
 272         /* wait for the syncpoint, or timeout, or signal */
 273         while (timeout) {
 274                 long check = min_t(long, SYNCPT_CHECK_PERIOD, timeout);
 275                 int remain;
 276
 277                 remain = wait_event_interruptible_timeout(wq,
 278                                 syncpt_load_min_is_expired(sp, thresh),
 279                                 check);
 280                 if (remain > 0 || host1x_syncpt_is_expired(sp, thresh)) {
 281                         if (value)
 282                                 *value = host1x_syncpt_load(sp);
 283
 284                         err = 0;
 285
 286                         break;
 287                 }
 288
 289                 if (remain < 0) {
 290                         err = remain;
 291                         break;
 292                 }
 293
 294                 timeout -= check;
 295
 296                 if (timeout && check_count <= MAX_STUCK_CHECK_COUNT) {
 297                         dev_warn(sp->host->dev,
 298                                 "%s: syncpoint id %u (%s) stuck waiting %d, timeout=%ld\n",
 299                                  current->comm, sp->id, sp->name,
 300                                  thresh, timeout);
 301
 302                         host1x_debug_dump_syncpts(sp->host);
 303
 304                         if (check_count == MAX_STUCK_CHECK_COUNT)
 305                                 host1x_debug_dump(sp->host);
 306
 307                         check_count++;
 308                 }
 309         }
 310
 311         host1x_intr_put_ref(sp->host, sp->id, ref, true);
 312
 313 done:
 314         return err;
 315 }
 316 EXPORT_SYMBOL(host1x_syncpt_wait);
 317
 318 /*
 319  * Returns true if syncpoint is expired, false if we may need to wait
 320  */
 321 bool host1x_syncpt_is_expired(struct host1x_syncpt *sp, u32 thresh)
 322 {
 323         u32 current_val;
 324
 325         smp_rmb();
 326
 327         current_val = (u32)atomic_read(&sp->min_val);
 328
 329         return ((current_val - thresh) & 0x80000000U) == 0U;
 330 }
 331
 332 int host1x_syncpt_init(struct host1x *host)
 333 {
 334         struct host1x_syncpt_base *bases;
 335         struct host1x_syncpt *syncpt;
 336         unsigned int i;
 337
 338         syncpt = devm_kcalloc(host->dev, host->info->nb_pts, sizeof(*syncpt),
 339                               GFP_KERNEL);
 340         if (!syncpt)
 341                 return -ENOMEM;
 342
 343         bases = devm_kcalloc(host->dev, host->info->nb_bases, sizeof(*bases),
 344                              GFP_KERNEL);
 345         if (!bases)
 346                 return -ENOMEM;
 347
 348         for (i = 0; i < host->info->nb_pts; i++) {
 349                 syncpt[i].id = i;
 350                 syncpt[i].host = host;
 351
 352                 /*
 353                  * Unassign syncpt from channels for purposes of Tegra186
 354                  * syncpoint protection. This prevents any channel from
 355                  * accessing it until it is reassigned.
 356                  */
 357                 host1x_hw_syncpt_assign_to_channel(host, &syncpt[i], NULL);
 358         }
 359
 360         for (i = 0; i < host->info->nb_bases; i++)
 361                 bases[i].id = i;
 362
 363         mutex_init(&host->syncpt_mutex);
 364         host->syncpt = syncpt;
 365         host->bases = bases;
 366
 367         host1x_syncpt_restore(host);
 368         host1x_hw_syncpt_enable_protection(host);
 369
 370         /* Allocate sync point to use for clearing waits for expired fences */
 371         host->nop_sp = host1x_syncpt_alloc(host, 0, "reserved-nop");
 372         if (!host->nop_sp)
 373                 return -ENOMEM;
 374
 375         return 0;
 376 }
 377
 378 /**
 379  * host1x_syncpt_request() - request a syncpoint
 380  * @client: client requesting the syncpoint
 381  * @flags: flags
 382  *
 383  * host1x client drivers can use this function to allocate a syncpoint for
 384  * subsequent use. A syncpoint returned by this function will be reserved for
 385  * use by the client exclusively. When no longer using a syncpoint, a host1x
 386  * client driver needs to release it using host1x_syncpt_free().
 387  */
 388 struct host1x_syncpt *host1x_syncpt_request(struct host1x_client *client,
 389                                             unsigned long flags)
 390 {
 391         struct host1x *host = dev_get_drvdata(client->host->parent);
 392
 393         return host1x_syncpt_alloc(host, flags, dev_name(client->dev));
 394 }
 395 EXPORT_SYMBOL(host1x_syncpt_request);
 396
 397 /**
 398  * host1x_syncpt_free() - free a requested syncpoint
 399  * @sp: host1x syncpoint
 400  *
 401  * Release a syncpoint previously allocated using host1x_syncpt_request(). A
 402  * host1x client driver should call this when the syncpoint is no longer in
 403  * use. Note that client drivers must ensure that the syncpoint doesn't remain
 404  * under the control of hardware after calling this function, otherwise two
 405  * clients may end up trying to access the same syncpoint concurrently.
 406  */
 407 void host1x_syncpt_free(struct host1x_syncpt *sp)
 408 {
 409         if (!sp)
 410                 return;
 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 EXPORT_SYMBOL(host1x_syncpt_free);
 423
 424 void host1x_syncpt_deinit(struct host1x *host)
 425 {
 426         struct host1x_syncpt *sp = host->syncpt;
 427         unsigned int i;
 428
 429         for (i = 0; i < host->info->nb_pts; i++, sp++)
 430                 kfree(sp->name);
 431 }
 432
 433 /**
 434  * host1x_syncpt_read_max() - read maximum syncpoint value
 435  * @sp: host1x syncpoint
 436  *
 437  * The maximum syncpoint value indicates how many operations there are in
 438  * queue, either in channel or in a software thread.
 439  */
 440 u32 host1x_syncpt_read_max(struct host1x_syncpt *sp)
 441 {
 442         smp_rmb();
 443
 444         return (u32)atomic_read(&sp->max_val);
 445 }
 446 EXPORT_SYMBOL(host1x_syncpt_read_max);
 447
 448 /**
 449  * host1x_syncpt_read_min() - read minimum syncpoint value
 450  * @sp: host1x syncpoint
 451  *
 452  * The minimum syncpoint value is a shadow of the current sync point value in
 453  * hardware.
 454  */
 455 u32 host1x_syncpt_read_min(struct host1x_syncpt *sp)
 456 {
 457         smp_rmb();
 458
 459         return (u32)atomic_read(&sp->min_val);
 460 }
 461 EXPORT_SYMBOL(host1x_syncpt_read_min);
 462
 463 /**
 464  * host1x_syncpt_read() - read the current syncpoint value
 465  * @sp: host1x syncpoint
 466  */
 467 u32 host1x_syncpt_read(struct host1x_syncpt *sp)
 468 {
 469         return host1x_syncpt_load(sp);
 470 }
 471 EXPORT_SYMBOL(host1x_syncpt_read);
 472
 473 unsigned int host1x_syncpt_nb_pts(struct host1x *host)
 474 {
 475         return host->info->nb_pts;
 476 }
 477
 478 unsigned int host1x_syncpt_nb_bases(struct host1x *host)
 479 {
 480         return host->info->nb_bases;
 481 }
 482
 483 unsigned int host1x_syncpt_nb_mlocks(struct host1x *host)
 484 {
 485         return host->info->nb_mlocks;
 486 }
 487
 488 /**
 489  * host1x_syncpt_get() - obtain a syncpoint by ID
 490  * @host: host1x controller
 491  * @id: syncpoint ID
 492  */
 493 struct host1x_syncpt *host1x_syncpt_get(struct host1x *host, unsigned int id)
 494 {
 495         if (id >= host->info->nb_pts)
 496                 return NULL;
 497
 498         return host->syncpt + id;
 499 }
 500 EXPORT_SYMBOL(host1x_syncpt_get);
 501
 502 /**
 503  * host1x_syncpt_get_base() - obtain the wait base associated with a syncpoint
 504  * @sp: host1x syncpoint
 505  */
 506 struct host1x_syncpt_base *host1x_syncpt_get_base(struct host1x_syncpt *sp)
 507 {
 508         return sp ? sp->base : NULL;
 509 }
 510 EXPORT_SYMBOL(host1x_syncpt_get_base);
 511
 512 /**
 513  * host1x_syncpt_base_id() - retrieve the ID of a syncpoint wait base
 514  * @base: host1x syncpoint wait base
 515  */
 516 u32 host1x_syncpt_base_id(struct host1x_syncpt_base *base)
 517 {
 518         return base->id;
 519 }
 520 EXPORT_SYMBOL(host1x_syncpt_base_id);