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 static struct host1x_syncpt *host1x_syncpt_alloc(struct host1x *host,
  46                                                  struct host1x_client *client,
  47                                                  unsigned long flags)
  48 {
  49         struct host1x_syncpt *sp = host->syncpt;
  50         unsigned int i;
  51         char *name;
  52
  53         mutex_lock(&host->syncpt_mutex);
  54
  55         for (i = 0; i < host->info->nb_pts && sp->name; i++, sp++)
  56                 ;
  57
  58         if (i >= host->info->nb_pts)
  59                 goto unlock;
  60
  61         if (flags & HOST1X_SYNCPT_HAS_BASE) {
  62                 sp->base = host1x_syncpt_base_request(host);
  63                 if (!sp->base)
  64                         goto unlock;
  65         }
  66
  67         name = kasprintf(GFP_KERNEL, "%02u-%s", sp->id,
  68                          client ? dev_name(client->dev) : NULL);
  69         if (!name)
  70                 goto free_base;
  71
  72         sp->client = client;
  73         sp->name = name;
  74
  75         if (flags & HOST1X_SYNCPT_CLIENT_MANAGED)
  76                 sp->client_managed = true;
  77         else
  78                 sp->client_managed = false;
  79
  80         mutex_unlock(&host->syncpt_mutex);
  81         return sp;
  82
  83 free_base:
  84         host1x_syncpt_base_free(sp->base);
  85         sp->base = NULL;
  86 unlock:
  87         mutex_unlock(&host->syncpt_mutex);
  88         return NULL;
  89 }
  90
  91 /**
  92  * host1x_syncpt_id() - retrieve syncpoint ID
  93  * @sp: host1x syncpoint
  94  *
  95  * Given a pointer to a struct host1x_syncpt, retrieves its ID. This ID is
  96  * often used as a value to program into registers that control how hardware
  97  * blocks interact with syncpoints.
  98  */
  99 u32 host1x_syncpt_id(struct host1x_syncpt *sp)
 100 {
 101         return sp->id;
 102 }
 103 EXPORT_SYMBOL(host1x_syncpt_id);
 104
 105 /**
 106  * host1x_syncpt_incr_max() - update the value sent to hardware
 107  * @sp: host1x syncpoint
 108  * @incrs: number of increments
 109  */
 110 u32 host1x_syncpt_incr_max(struct host1x_syncpt *sp, u32 incrs)
 111 {
 112         return (u32)atomic_add_return(incrs, &sp->max_val);
 113 }
 114 EXPORT_SYMBOL(host1x_syncpt_incr_max);
 115
 116  /*
 117  * Write cached syncpoint and waitbase values to hardware.
 118  */
 119 void host1x_syncpt_restore(struct host1x *host)
 120 {
 121         struct host1x_syncpt *sp_base = host->syncpt;
 122         unsigned int i;
 123
 124         for (i = 0; i < host1x_syncpt_nb_pts(host); i++)
 125                 host1x_hw_syncpt_restore(host, sp_base + i);
 126
 127         for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
 128                 host1x_hw_syncpt_restore_wait_base(host, sp_base + i);
 129
 130         wmb();
 131 }
 132
 133 /*
 134  * Update the cached syncpoint and waitbase values by reading them
 135  * from the registers.
 136   */
 137 void host1x_syncpt_save(struct host1x *host)
 138 {
 139         struct host1x_syncpt *sp_base = host->syncpt;
 140         unsigned int i;
 141
 142         for (i = 0; i < host1x_syncpt_nb_pts(host); i++) {
 143                 if (host1x_syncpt_client_managed(sp_base + i))
 144                         host1x_hw_syncpt_load(host, sp_base + i);
 145                 else
 146                         WARN_ON(!host1x_syncpt_idle(sp_base + i));
 147         }
 148
 149         for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
 150                 host1x_hw_syncpt_load_wait_base(host, sp_base + i);
 151 }
 152
 153 /*
 154  * Updates the cached syncpoint value by reading a new value from the hardware
 155  * register
 156  */
 157 u32 host1x_syncpt_load(struct host1x_syncpt *sp)
 158 {
 159         u32 val;
 160
 161         val = host1x_hw_syncpt_load(sp->host, sp);
 162         trace_host1x_syncpt_load_min(sp->id, val);
 163
 164         return val;
 165 }
 166
 167 /*
 168  * Get the current syncpoint base
 169  */
 170 u32 host1x_syncpt_load_wait_base(struct host1x_syncpt *sp)
 171 {
 172         host1x_hw_syncpt_load_wait_base(sp->host, sp);
 173
 174         return sp->base_val;
 175 }
 176
 177 /**
 178  * host1x_syncpt_incr() - increment syncpoint value from CPU, updating cache
 179  * @sp: host1x syncpoint
 180  */
 181 int host1x_syncpt_incr(struct host1x_syncpt *sp)
 182 {
 183         return host1x_hw_syncpt_cpu_incr(sp->host, sp);
 184 }
 185 EXPORT_SYMBOL(host1x_syncpt_incr);
 186
 187 /*
 188  * Updated sync point form hardware, and returns true if syncpoint is expired,
 189  * false if we may need to wait
 190  */
 191 static bool syncpt_load_min_is_expired(struct host1x_syncpt *sp, u32 thresh)
 192 {
 193         host1x_hw_syncpt_load(sp->host, sp);
 194
 195         return host1x_syncpt_is_expired(sp, thresh);
 196 }
 197
 198 /**
 199  * host1x_syncpt_wait() - wait for a syncpoint to reach a given value
 200  * @sp: host1x syncpoint
 201  * @thresh: threshold
 202  * @timeout: maximum time to wait for the syncpoint to reach the given value
 203  * @value: return location for the syncpoint value
 204  */
 205 int host1x_syncpt_wait(struct host1x_syncpt *sp, u32 thresh, long timeout,
 206                        u32 *value)
 207 {
 208         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
 209         void *ref;
 210         struct host1x_waitlist *waiter;
 211         int err = 0, check_count = 0;
 212         u32 val;
 213
 214         if (value)
 215                 *value = 0;
 216
 217         /* first check cache */
 218         if (host1x_syncpt_is_expired(sp, thresh)) {
 219                 if (value)
 220                         *value = host1x_syncpt_load(sp);
 221
 222                 return 0;
 223         }
 224
 225         /* try to read from register */
 226         val = host1x_hw_syncpt_load(sp->host, sp);
 227         if (host1x_syncpt_is_expired(sp, thresh)) {
 228                 if (value)
 229                         *value = val;
 230
 231                 goto done;
 232         }
 233
 234         if (!timeout) {
 235                 err = -EAGAIN;
 236                 goto done;
 237         }
 238
 239         /* allocate a waiter */
 240         waiter = kzalloc(sizeof(*waiter), GFP_KERNEL);
 241         if (!waiter) {
 242                 err = -ENOMEM;
 243                 goto done;
 244         }
 245
 246         /* schedule a wakeup when the syncpoint value is reached */
 247         err = host1x_intr_add_action(sp->host, sp, thresh,
 248                                      HOST1X_INTR_ACTION_WAKEUP_INTERRUPTIBLE,
 249                                      &wq, waiter, &ref);
 250         if (err)
 251                 goto done;
 252
 253         err = -EAGAIN;
 254         /* Caller-specified timeout may be impractically low */
 255         if (timeout < 0)
 256                 timeout = LONG_MAX;
 257
 258         /* wait for the syncpoint, or timeout, or signal */
 259         while (timeout) {
 260                 long check = min_t(long, SYNCPT_CHECK_PERIOD, timeout);
 261                 int remain;
 262
 263                 remain = wait_event_interruptible_timeout(wq,
 264                                 syncpt_load_min_is_expired(sp, thresh),
 265                                 check);
 266                 if (remain > 0 || host1x_syncpt_is_expired(sp, thresh)) {
 267                         if (value)
 268                                 *value = host1x_syncpt_load(sp);
 269
 270                         err = 0;
 271
 272                         break;
 273                 }
 274
 275                 if (remain < 0) {
 276                         err = remain;
 277                         break;
 278                 }
 279
 280                 timeout -= check;
 281
 282                 if (timeout && check_count <= MAX_STUCK_CHECK_COUNT) {
 283                         dev_warn(sp->host->dev,
 284                                 "%s: syncpoint id %u (%s) stuck waiting %d, timeout=%ld\n",
 285                                  current->comm, sp->id, sp->name,
 286                                  thresh, timeout);
 287
 288                         host1x_debug_dump_syncpts(sp->host);
 289
 290                         if (check_count == MAX_STUCK_CHECK_COUNT)
 291                                 host1x_debug_dump(sp->host);
 292
 293                         check_count++;
 294                 }
 295         }
 296
 297         host1x_intr_put_ref(sp->host, sp->id, ref);
 298
 299 done:
 300         return err;
 301 }
 302 EXPORT_SYMBOL(host1x_syncpt_wait);
 303
 304 /*
 305  * Returns true if syncpoint is expired, false if we may need to wait
 306  */
 307 bool host1x_syncpt_is_expired(struct host1x_syncpt *sp, u32 thresh)
 308 {
 309         u32 current_val;
 310         u32 future_val;
 311
 312         smp_rmb();
 313
 314         current_val = (u32)atomic_read(&sp->min_val);
 315         future_val = (u32)atomic_read(&sp->max_val);
 316
 317         /* Note the use of unsigned arithmetic here (mod 1<<32).
 318          *
 319          * c = current_val = min_val    = the current value of the syncpoint.
 320          * t = thresh                   = the value we are checking
 321          * f = future_val  = max_val    = the value c will reach when all
 322          *                                outstanding increments have completed.
 323          *
 324          * Note that c always chases f until it reaches f.
 325          *
 326          * Dtf = (f - t)
 327          * Dtc = (c - t)
 328          *
 329          *  Consider all cases:
 330          *
 331          *      A) .....c..t..f.....    Dtf < Dtc       need to wait
 332          *      B) .....c.....f..t..    Dtf > Dtc       expired
 333          *      C) ..t..c.....f.....    Dtf > Dtc       expired    (Dct very large)
 334          *
 335          *  Any case where f==c: always expired (for any t).    Dtf == Dcf
 336          *  Any case where t==c: always expired (for any f).    Dtf >= Dtc (because Dtc==0)
 337          *  Any case where t==f!=c: always wait.                Dtf <  Dtc (because Dtf==0,
 338          *                                                      Dtc!=0)
 339          *
 340          *  Other cases:
 341          *
 342          *      A) .....t..f..c.....    Dtf < Dtc       need to wait
 343          *      A) .....f..c..t.....    Dtf < Dtc       need to wait
 344          *      A) .....f..t..c.....    Dtf > Dtc       expired
 345          *
 346          *   So:
 347          *         Dtf >= Dtc implies EXPIRED   (return true)
 348          *         Dtf <  Dtc implies WAIT      (return false)
 349          *
 350          * Note: If t is expired then we *cannot* wait on it. We would wait
 351          * forever (hang the system).
 352          *
 353          * Note: do NOT get clever and remove the -thresh from both sides. It
 354          * is NOT the same.
 355          *
 356          * If future valueis zero, we have a client managed sync point. In that
 357          * case we do a direct comparison.
 358          */
 359         if (!host1x_syncpt_client_managed(sp))
 360                 return future_val - thresh >= current_val - thresh;
 361         else
 362                 return (s32)(current_val - thresh) >= 0;
 363 }
 364
 365 int host1x_syncpt_init(struct host1x *host)
 366 {
 367         struct host1x_syncpt_base *bases;
 368         struct host1x_syncpt *syncpt;
 369         unsigned int i;
 370
 371         syncpt = devm_kcalloc(host->dev, host->info->nb_pts, sizeof(*syncpt),
 372                               GFP_KERNEL);
 373         if (!syncpt)
 374                 return -ENOMEM;
 375
 376         bases = devm_kcalloc(host->dev, host->info->nb_bases, sizeof(*bases),
 377                              GFP_KERNEL);
 378         if (!bases)
 379                 return -ENOMEM;
 380
 381         for (i = 0; i < host->info->nb_pts; i++) {
 382                 syncpt[i].id = i;
 383                 syncpt[i].host = host;
 384
 385                 /*
 386                  * Unassign syncpt from channels for purposes of Tegra186
 387                  * syncpoint protection. This prevents any channel from
 388                  * accessing it until it is reassigned.
 389                  */
 390                 host1x_hw_syncpt_assign_to_channel(host, &syncpt[i], NULL);
 391         }
 392
 393         for (i = 0; i < host->info->nb_bases; i++)
 394                 bases[i].id = i;
 395
 396         mutex_init(&host->syncpt_mutex);
 397         host->syncpt = syncpt;
 398         host->bases = bases;
 399
 400         host1x_syncpt_restore(host);
 401         host1x_hw_syncpt_enable_protection(host);
 402
 403         /* Allocate sync point to use for clearing waits for expired fences */
 404         host->nop_sp = host1x_syncpt_alloc(host, NULL, 0);
 405         if (!host->nop_sp)
 406                 return -ENOMEM;
 407
 408         return 0;
 409 }
 410
 411 /**
 412  * host1x_syncpt_request() - request a syncpoint
 413  * @client: client requesting the syncpoint
 414  * @flags: flags
 415  *
 416  * host1x client drivers can use this function to allocate a syncpoint for
 417  * subsequent use. A syncpoint returned by this function will be reserved for
 418  * use by the client exclusively. When no longer using a syncpoint, a host1x
 419  * client driver needs to release it using host1x_syncpt_free().
 420  */
 421 struct host1x_syncpt *host1x_syncpt_request(struct host1x_client *client,
 422                                             unsigned long flags)
 423 {
 424         struct host1x *host = dev_get_drvdata(client->parent->parent);
 425
 426         return host1x_syncpt_alloc(host, client, flags);
 427 }
 428 EXPORT_SYMBOL(host1x_syncpt_request);
 429
 430 /**
 431  * host1x_syncpt_free() - free a requested syncpoint
 432  * @sp: host1x syncpoint
 433  *
 434  * Release a syncpoint previously allocated using host1x_syncpt_request(). A
 435  * host1x client driver should call this when the syncpoint is no longer in
 436  * use. Note that client drivers must ensure that the syncpoint doesn't remain
 437  * under the control of hardware after calling this function, otherwise two
 438  * clients may end up trying to access the same syncpoint concurrently.
 439  */
 440 void host1x_syncpt_free(struct host1x_syncpt *sp)
 441 {
 442         if (!sp)
 443                 return;
 444
 445         mutex_lock(&sp->host->syncpt_mutex);
 446
 447         host1x_syncpt_base_free(sp->base);
 448         kfree(sp->name);
 449         sp->base = NULL;
 450         sp->client = NULL;
 451         sp->name = NULL;
 452         sp->client_managed = false;
 453
 454         mutex_unlock(&sp->host->syncpt_mutex);
 455 }
 456 EXPORT_SYMBOL(host1x_syncpt_free);
 457
 458 void host1x_syncpt_deinit(struct host1x *host)
 459 {
 460         struct host1x_syncpt *sp = host->syncpt;
 461         unsigned int i;
 462
 463         for (i = 0; i < host->info->nb_pts; i++, sp++)
 464                 kfree(sp->name);
 465 }
 466
 467 /**
 468  * host1x_syncpt_read_max() - read maximum syncpoint value
 469  * @sp: host1x syncpoint
 470  *
 471  * The maximum syncpoint value indicates how many operations there are in
 472  * queue, either in channel or in a software thread.
 473  */
 474 u32 host1x_syncpt_read_max(struct host1x_syncpt *sp)
 475 {
 476         smp_rmb();
 477
 478         return (u32)atomic_read(&sp->max_val);
 479 }
 480 EXPORT_SYMBOL(host1x_syncpt_read_max);
 481
 482 /**
 483  * host1x_syncpt_read_min() - read minimum syncpoint value
 484  * @sp: host1x syncpoint
 485  *
 486  * The minimum syncpoint value is a shadow of the current sync point value in
 487  * hardware.
 488  */
 489 u32 host1x_syncpt_read_min(struct host1x_syncpt *sp)
 490 {
 491         smp_rmb();
 492
 493         return (u32)atomic_read(&sp->min_val);
 494 }
 495 EXPORT_SYMBOL(host1x_syncpt_read_min);
 496
 497 /**
 498  * host1x_syncpt_read() - read the current syncpoint value
 499  * @sp: host1x syncpoint
 500  */
 501 u32 host1x_syncpt_read(struct host1x_syncpt *sp)
 502 {
 503         return host1x_syncpt_load(sp);
 504 }
 505 EXPORT_SYMBOL(host1x_syncpt_read);
 506
 507 unsigned int host1x_syncpt_nb_pts(struct host1x *host)
 508 {
 509         return host->info->nb_pts;
 510 }
 511
 512 unsigned int host1x_syncpt_nb_bases(struct host1x *host)
 513 {
 514         return host->info->nb_bases;
 515 }
 516
 517 unsigned int host1x_syncpt_nb_mlocks(struct host1x *host)
 518 {
 519         return host->info->nb_mlocks;
 520 }
 521
 522 /**
 523  * host1x_syncpt_get() - obtain a syncpoint by ID
 524  * @host: host1x controller
 525  * @id: syncpoint ID
 526  */
 527 struct host1x_syncpt *host1x_syncpt_get(struct host1x *host, unsigned int id)
 528 {
 529         if (id >= host->info->nb_pts)
 530                 return NULL;
 531
 532         return host->syncpt + id;
 533 }
 534 EXPORT_SYMBOL(host1x_syncpt_get);
 535
 536 /**
 537  * host1x_syncpt_get_base() - obtain the wait base associated with a syncpoint
 538  * @sp: host1x syncpoint
 539  */
 540 struct host1x_syncpt_base *host1x_syncpt_get_base(struct host1x_syncpt *sp)
 541 {
 542         return sp ? sp->base : NULL;
 543 }
 544 EXPORT_SYMBOL(host1x_syncpt_get_base);
 545
 546 /**
 547  * host1x_syncpt_base_id() - retrieve the ID of a syncpoint wait base
 548  * @base: host1x syncpoint wait base
 549  */
 550 u32 host1x_syncpt_base_id(struct host1x_syncpt_base *base)
 551 {
 552         return base->id;
 553 }
 554 EXPORT_SYMBOL(host1x_syncpt_base_id);