drivers/gpu/host1x/syncpt.c

   1 /*
   2  * Tegra host1x Syncpoints
   3  *
   4  * Copyright (c) 2010-2015, NVIDIA Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/device.h>
  21 #include <linux/slab.h>
  22
  23 #include <trace/events/host1x.h>
  24
  25 #include "syncpt.h"
  26 #include "dev.h"
  27 #include "intr.h"
  28 #include "debug.h"
  29
  30 #define SYNCPT_CHECK_PERIOD (2 * HZ)
  31 #define MAX_STUCK_CHECK_COUNT 15
  32
  33 static struct host1x_syncpt_base *
  34 host1x_syncpt_base_request(struct host1x *host)
  35 {
  36         struct host1x_syncpt_base *bases = host->bases;
  37         unsigned int i;
  38
  39         for (i = 0; i < host->info->nb_bases; i++)
  40                 if (!bases[i].requested)
  41                         break;
  42
  43         if (i >= host->info->nb_bases)
  44                 return NULL;
  45
  46         bases[i].requested = true;
  47         return &bases[i];
  48 }
  49
  50 static void host1x_syncpt_base_free(struct host1x_syncpt_base *base)
  51 {
  52         if (base)
  53                 base->requested = false;
  54 }
  55
  56 static struct host1x_syncpt *host1x_syncpt_alloc(struct host1x *host,
  57                                                  struct host1x_client *client,
  58                                                  unsigned long flags)
  59 {
  60         int i;
  61         struct host1x_syncpt *sp = host->syncpt;
  62         char *name;
  63
  64         mutex_lock(&host->syncpt_mutex);
  65
  66         for (i = 0; i < host->info->nb_pts && sp->name; i++, sp++)
  67                 ;
  68
  69         if (i >= host->info->nb_pts)
  70                 goto unlock;
  71
  72         if (flags & HOST1X_SYNCPT_HAS_BASE) {
  73                 sp->base = host1x_syncpt_base_request(host);
  74                 if (!sp->base)
  75                         goto unlock;
  76         }
  77
  78         name = kasprintf(GFP_KERNEL, "%02u-%s", sp->id,
  79                          client ? dev_name(client->dev) : NULL);
  80         if (!name)
  81                 goto free_base;
  82
  83         sp->client = client;
  84         sp->name = name;
  85
  86         if (flags & HOST1X_SYNCPT_CLIENT_MANAGED)
  87                 sp->client_managed = true;
  88         else
  89                 sp->client_managed = false;
  90
  91         mutex_unlock(&host->syncpt_mutex);
  92         return sp;
  93
  94 free_base:
  95         host1x_syncpt_base_free(sp->base);
  96         sp->base = NULL;
  97 unlock:
  98         mutex_unlock(&host->syncpt_mutex);
  99         return NULL;
 100 }
 101
 102 /**
 103  * host1x_syncpt_id() - retrieve syncpoint ID
 104  * @sp: host1x syncpoint
 105  *
 106  * Given a pointer to a struct host1x_syncpt, retrieves its ID. This ID is
 107  * often used as a value to program into registers that control how hardware
 108  * blocks interact with syncpoints.
 109  */
 110 u32 host1x_syncpt_id(struct host1x_syncpt *sp)
 111 {
 112         return sp->id;
 113 }
 114 EXPORT_SYMBOL(host1x_syncpt_id);
 115
 116 /**
 117  * host1x_syncpt_incr_max() - update the value sent to hardware
 118  * @sp: host1x syncpoint
 119  * @incrs: number of increments
 120  */
 121 u32 host1x_syncpt_incr_max(struct host1x_syncpt *sp, u32 incrs)
 122 {
 123         return (u32)atomic_add_return(incrs, &sp->max_val);
 124 }
 125 EXPORT_SYMBOL(host1x_syncpt_incr_max);
 126
 127  /*
 128  * Write cached syncpoint and waitbase values to hardware.
 129  */
 130 void host1x_syncpt_restore(struct host1x *host)
 131 {
 132         struct host1x_syncpt *sp_base = host->syncpt;
 133         unsigned int i;
 134
 135         for (i = 0; i < host1x_syncpt_nb_pts(host); i++)
 136                 host1x_hw_syncpt_restore(host, sp_base + i);
 137
 138         for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
 139                 host1x_hw_syncpt_restore_wait_base(host, sp_base + i);
 140
 141         wmb();
 142 }
 143
 144 /*
 145  * Update the cached syncpoint and waitbase values by reading them
 146  * from the registers.
 147   */
 148 void host1x_syncpt_save(struct host1x *host)
 149 {
 150         struct host1x_syncpt *sp_base = host->syncpt;
 151         unsigned int i;
 152
 153         for (i = 0; i < host1x_syncpt_nb_pts(host); i++) {
 154                 if (host1x_syncpt_client_managed(sp_base + i))
 155                         host1x_hw_syncpt_load(host, sp_base + i);
 156                 else
 157                         WARN_ON(!host1x_syncpt_idle(sp_base + i));
 158         }
 159
 160         for (i = 0; i < host1x_syncpt_nb_bases(host); i++)
 161                 host1x_hw_syncpt_load_wait_base(host, sp_base + i);
 162 }
 163
 164 /*
 165  * Updates the cached syncpoint value by reading a new value from the hardware
 166  * register
 167  */
 168 u32 host1x_syncpt_load(struct host1x_syncpt *sp)
 169 {
 170         u32 val;
 171
 172         val = host1x_hw_syncpt_load(sp->host, sp);
 173         trace_host1x_syncpt_load_min(sp->id, val);
 174
 175         return val;
 176 }
 177
 178 /*
 179  * Get the current syncpoint base
 180  */
 181 u32 host1x_syncpt_load_wait_base(struct host1x_syncpt *sp)
 182 {
 183         host1x_hw_syncpt_load_wait_base(sp->host, sp);
 184
 185         return sp->base_val;
 186 }
 187
 188 /**
 189  * host1x_syncpt_incr() - increment syncpoint value from CPU, updating cache
 190  * @sp: host1x syncpoint
 191  */
 192 int host1x_syncpt_incr(struct host1x_syncpt *sp)
 193 {
 194         return host1x_hw_syncpt_cpu_incr(sp->host, sp);
 195 }
 196 EXPORT_SYMBOL(host1x_syncpt_incr);
 197
 198 /*
 199  * Updated sync point form hardware, and returns true if syncpoint is expired,
 200  * false if we may need to wait
 201  */
 202 static bool syncpt_load_min_is_expired(struct host1x_syncpt *sp, u32 thresh)
 203 {
 204         host1x_hw_syncpt_load(sp->host, sp);
 205
 206         return host1x_syncpt_is_expired(sp, thresh);
 207 }
 208
 209 /**
 210  * host1x_syncpt_wait() - wait for a syncpoint to reach a given value
 211  * @sp: host1x syncpoint
 212  * @thresh: threshold
 213  * @timeout: maximum time to wait for the syncpoint to reach the given value
 214  * @value: return location for the syncpoint value
 215  */
 216 int host1x_syncpt_wait(struct host1x_syncpt *sp, u32 thresh, long timeout,
 217                        u32 *value)
 218 {
 219         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
 220         void *ref;
 221         struct host1x_waitlist *waiter;
 222         int err = 0, check_count = 0;
 223         u32 val;
 224
 225         if (value)
 226                 *value = 0;
 227
 228         /* first check cache */
 229         if (host1x_syncpt_is_expired(sp, thresh)) {
 230                 if (value)
 231                         *value = host1x_syncpt_load(sp);
 232
 233                 return 0;
 234         }
 235
 236         /* try to read from register */
 237         val = host1x_hw_syncpt_load(sp->host, sp);
 238         if (host1x_syncpt_is_expired(sp, thresh)) {
 239                 if (value)
 240                         *value = val;
 241
 242                 goto done;
 243         }
 244
 245         if (!timeout) {
 246                 err = -EAGAIN;
 247                 goto done;
 248         }
 249
 250         /* allocate a waiter */
 251         waiter = kzalloc(sizeof(*waiter), GFP_KERNEL);
 252         if (!waiter) {
 253                 err = -ENOMEM;
 254                 goto done;
 255         }
 256
 257         /* schedule a wakeup when the syncpoint value is reached */
 258         err = host1x_intr_add_action(sp->host, sp->id, thresh,
 259                                      HOST1X_INTR_ACTION_WAKEUP_INTERRUPTIBLE,
 260                                      &wq, waiter, &ref);
 261         if (err)
 262                 goto done;
 263
 264         err = -EAGAIN;
 265         /* Caller-specified timeout may be impractically low */
 266         if (timeout < 0)
 267                 timeout = LONG_MAX;
 268
 269         /* wait for the syncpoint, or timeout, or signal */
 270         while (timeout) {
 271                 long check = min_t(long, SYNCPT_CHECK_PERIOD, timeout);
 272                 int remain;
 273
 274                 remain = wait_event_interruptible_timeout(wq,
 275                                 syncpt_load_min_is_expired(sp, thresh),
 276                                 check);
 277                 if (remain > 0 || host1x_syncpt_is_expired(sp, thresh)) {
 278                         if (value)
 279                                 *value = host1x_syncpt_load(sp);
 280
 281                         err = 0;
 282
 283                         break;
 284                 }
 285
 286                 if (remain < 0) {
 287                         err = remain;
 288                         break;
 289                 }
 290
 291                 timeout -= check;
 292
 293                 if (timeout && check_count <= MAX_STUCK_CHECK_COUNT) {
 294                         dev_warn(sp->host->dev,
 295                                 "%s: syncpoint id %u (%s) stuck waiting %d, timeout=%ld\n",
 296                                  current->comm, sp->id, sp->name,
 297                                  thresh, timeout);
 298
 299                         host1x_debug_dump_syncpts(sp->host);
 300
 301                         if (check_count == MAX_STUCK_CHECK_COUNT)
 302                                 host1x_debug_dump(sp->host);
 303
 304                         check_count++;
 305                 }
 306         }
 307
 308         host1x_intr_put_ref(sp->host, sp->id, ref);
 309
 310 done:
 311         return err;
 312 }
 313 EXPORT_SYMBOL(host1x_syncpt_wait);
 314
 315 /*
 316  * Returns true if syncpoint is expired, false if we may need to wait
 317  */
 318 bool host1x_syncpt_is_expired(struct host1x_syncpt *sp, u32 thresh)
 319 {
 320         u32 current_val;
 321         u32 future_val;
 322
 323         smp_rmb();
 324
 325         current_val = (u32)atomic_read(&sp->min_val);
 326         future_val = (u32)atomic_read(&sp->max_val);
 327
 328         /* Note the use of unsigned arithmetic here (mod 1<<32).
 329          *
 330          * c = current_val = min_val    = the current value of the syncpoint.
 331          * t = thresh                   = the value we are checking
 332          * f = future_val  = max_val    = the value c will reach when all
 333          *                                outstanding increments have completed.
 334          *
 335          * Note that c always chases f until it reaches f.
 336          *
 337          * Dtf = (f - t)
 338          * Dtc = (c - t)
 339          *
 340          *  Consider all cases:
 341          *
 342          *      A) .....c..t..f.....    Dtf < Dtc       need to wait
 343          *      B) .....c.....f..t..    Dtf > Dtc       expired
 344          *      C) ..t..c.....f.....    Dtf > Dtc       expired    (Dct very large)
 345          *
 346          *  Any case where f==c: always expired (for any t).    Dtf == Dcf
 347          *  Any case where t==c: always expired (for any f).    Dtf >= Dtc (because Dtc==0)
 348          *  Any case where t==f!=c: always wait.                Dtf <  Dtc (because Dtf==0,
 349          *                                                      Dtc!=0)
 350          *
 351          *  Other cases:
 352          *
 353          *      A) .....t..f..c.....    Dtf < Dtc       need to wait
 354          *      A) .....f..c..t.....    Dtf < Dtc       need to wait
 355          *      A) .....f..t..c.....    Dtf > Dtc       expired
 356          *
 357          *   So:
 358          *         Dtf >= Dtc implies EXPIRED   (return true)
 359          *         Dtf <  Dtc implies WAIT      (return false)
 360          *
 361          * Note: If t is expired then we *cannot* wait on it. We would wait
 362          * forever (hang the system).
 363          *
 364          * Note: do NOT get clever and remove the -thresh from both sides. It
 365          * is NOT the same.
 366          *
 367          * If future valueis zero, we have a client managed sync point. In that
 368          * case we do a direct comparison.
 369          */
 370         if (!host1x_syncpt_client_managed(sp))
 371                 return future_val - thresh >= current_val - thresh;
 372         else
 373                 return (s32)(current_val - thresh) >= 0;
 374 }
 375
 376 /* remove a wait pointed to by patch_addr */
 377 int host1x_syncpt_patch_wait(struct host1x_syncpt *sp, void *patch_addr)
 378 {
 379         return host1x_hw_syncpt_patch_wait(sp->host, sp, patch_addr);
 380 }
 381
 382 int host1x_syncpt_init(struct host1x *host)
 383 {
 384         struct host1x_syncpt_base *bases;
 385         struct host1x_syncpt *syncpt;
 386         unsigned int i;
 387
 388         syncpt = devm_kcalloc(host->dev, host->info->nb_pts, sizeof(*syncpt),
 389                               GFP_KERNEL);
 390         if (!syncpt)
 391                 return -ENOMEM;
 392
 393         bases = devm_kcalloc(host->dev, host->info->nb_bases, sizeof(*bases),
 394                              GFP_KERNEL);
 395         if (!bases)
 396                 return -ENOMEM;
 397
 398         for (i = 0; i < host->info->nb_pts; i++) {
 399                 syncpt[i].id = i;
 400                 syncpt[i].host = host;
 401
 402                 /*
 403                  * Unassign syncpt from channels for purposes of Tegra186
 404                  * syncpoint protection. This prevents any channel from
 405                  * accessing it until it is reassigned.
 406                  */
 407                 host1x_hw_syncpt_assign_to_channel(host, &syncpt[i], NULL);
 408         }
 409
 410         for (i = 0; i < host->info->nb_bases; i++)
 411                 bases[i].id = i;
 412
 413         mutex_init(&host->syncpt_mutex);
 414         host->syncpt = syncpt;
 415         host->bases = bases;
 416
 417         host1x_syncpt_restore(host);
 418         host1x_hw_syncpt_enable_protection(host);
 419
 420         /* Allocate sync point to use for clearing waits for expired fences */
 421         host->nop_sp = host1x_syncpt_alloc(host, NULL, 0);
 422         if (!host->nop_sp)
 423                 return -ENOMEM;
 424
 425         return 0;
 426 }
 427
 428 /**
 429  * host1x_syncpt_request() - request a syncpoint
 430  * @client: client requesting the syncpoint
 431  * @flags: flags
 432  *
 433  * host1x client drivers can use this function to allocate a syncpoint for
 434  * subsequent use. A syncpoint returned by this function will be reserved for
 435  * use by the client exclusively. When no longer using a syncpoint, a host1x
 436  * client driver needs to release it using host1x_syncpt_free().
 437  */
 438 struct host1x_syncpt *host1x_syncpt_request(struct host1x_client *client,
 439                                             unsigned long flags)
 440 {
 441         struct host1x *host = dev_get_drvdata(client->parent->parent);
 442
 443         return host1x_syncpt_alloc(host, client, flags);
 444 }
 445 EXPORT_SYMBOL(host1x_syncpt_request);
 446
 447 /**
 448  * host1x_syncpt_free() - free a requested syncpoint
 449  * @sp: host1x syncpoint
 450  *
 451  * Release a syncpoint previously allocated using host1x_syncpt_request(). A
 452  * host1x client driver should call this when the syncpoint is no longer in
 453  * use. Note that client drivers must ensure that the syncpoint doesn't remain
 454  * under the control of hardware after calling this function, otherwise two
 455  * clients may end up trying to access the same syncpoint concurrently.
 456  */
 457 void host1x_syncpt_free(struct host1x_syncpt *sp)
 458 {
 459         if (!sp)
 460                 return;
 461
 462         mutex_lock(&sp->host->syncpt_mutex);
 463
 464         host1x_syncpt_base_free(sp->base);
 465         kfree(sp->name);
 466         sp->base = NULL;
 467         sp->client = NULL;
 468         sp->name = NULL;
 469         sp->client_managed = false;
 470
 471         mutex_unlock(&sp->host->syncpt_mutex);
 472 }
 473 EXPORT_SYMBOL(host1x_syncpt_free);
 474
 475 void host1x_syncpt_deinit(struct host1x *host)
 476 {
 477         struct host1x_syncpt *sp = host->syncpt;
 478         unsigned int i;
 479
 480         for (i = 0; i < host->info->nb_pts; i++, sp++)
 481                 kfree(sp->name);
 482 }
 483
 484 /**
 485  * host1x_syncpt_read_max() - read maximum syncpoint value
 486  * @sp: host1x syncpoint
 487  *
 488  * The maximum syncpoint value indicates how many operations there are in
 489  * queue, either in channel or in a software thread.
 490  */
 491 u32 host1x_syncpt_read_max(struct host1x_syncpt *sp)
 492 {
 493         smp_rmb();
 494
 495         return (u32)atomic_read(&sp->max_val);
 496 }
 497 EXPORT_SYMBOL(host1x_syncpt_read_max);
 498
 499 /**
 500  * host1x_syncpt_read_min() - read minimum syncpoint value
 501  * @sp: host1x syncpoint
 502  *
 503  * The minimum syncpoint value is a shadow of the current sync point value in
 504  * hardware.
 505  */
 506 u32 host1x_syncpt_read_min(struct host1x_syncpt *sp)
 507 {
 508         smp_rmb();
 509
 510         return (u32)atomic_read(&sp->min_val);
 511 }
 512 EXPORT_SYMBOL(host1x_syncpt_read_min);
 513
 514 /**
 515  * host1x_syncpt_read() - read the current syncpoint value
 516  * @sp: host1x syncpoint
 517  */
 518 u32 host1x_syncpt_read(struct host1x_syncpt *sp)
 519 {
 520         return host1x_syncpt_load(sp);
 521 }
 522 EXPORT_SYMBOL(host1x_syncpt_read);
 523
 524 unsigned int host1x_syncpt_nb_pts(struct host1x *host)
 525 {
 526         return host->info->nb_pts;
 527 }
 528
 529 unsigned int host1x_syncpt_nb_bases(struct host1x *host)
 530 {
 531         return host->info->nb_bases;
 532 }
 533
 534 unsigned int host1x_syncpt_nb_mlocks(struct host1x *host)
 535 {
 536         return host->info->nb_mlocks;
 537 }
 538
 539 /**
 540  * host1x_syncpt_get() - obtain a syncpoint by ID
 541  * @host: host1x controller
 542  * @id: syncpoint ID
 543  */
 544 struct host1x_syncpt *host1x_syncpt_get(struct host1x *host, unsigned int id)
 545 {
 546         if (id >= host->info->nb_pts)
 547                 return NULL;
 548
 549         return host->syncpt + id;
 550 }
 551 EXPORT_SYMBOL(host1x_syncpt_get);
 552
 553 /**
 554  * host1x_syncpt_get_base() - obtain the wait base associated with a syncpoint
 555  * @sp: host1x syncpoint
 556  */
 557 struct host1x_syncpt_base *host1x_syncpt_get_base(struct host1x_syncpt *sp)
 558 {
 559         return sp ? sp->base : NULL;
 560 }
 561 EXPORT_SYMBOL(host1x_syncpt_get_base);
 562
 563 /**
 564  * host1x_syncpt_base_id() - retrieve the ID of a syncpoint wait base
 565  * @base: host1x syncpoint wait base
 566  */
 567 u32 host1x_syncpt_base_id(struct host1x_syncpt_base *base)
 568 {
 569         return base->id;
 570 }
 571 EXPORT_SYMBOL(host1x_syncpt_base_id);