linux/drivers/gpu/host1x/syncpt.c
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   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
  22static struct host1x_syncpt_base *
  23host1x_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
  39static 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 */
  57struct 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
  98free_base:
  99        host1x_syncpt_base_free(sp->base);
 100        sp->base = NULL;
 101unlock:
 102        mutex_unlock(&host->syncpt_mutex);
 103        return NULL;
 104}
 105EXPORT_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 */
 115u32 host1x_syncpt_id(struct host1x_syncpt *sp)
 116{
 117        return sp->id;
 118}
 119EXPORT_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 */
 126u32 host1x_syncpt_incr_max(struct host1x_syncpt *sp, u32 incrs)
 127{
 128        return (u32)atomic_add_return(incrs, &sp->max_val);
 129}
 130EXPORT_SYMBOL(host1x_syncpt_incr_max);
 131
 132 /*
 133 * Write cached syncpoint and waitbase values to hardware.
 134 */
 135void 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  */
 153void 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 */
 173u32 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 */
 186u32 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 */
 197int host1x_syncpt_incr(struct host1x_syncpt *sp)
 198{
 199        return host1x_hw_syncpt_cpu_incr(sp->host, sp);
 200}
 201EXPORT_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 */
 207static 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 */
 221int 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
 315done:
 316        return err;
 317}
 318EXPORT_SYMBOL(host1x_syncpt_wait);
 319
 320/*
 321 * Returns true if syncpoint is expired, false if we may need to wait
 322 */
 323bool 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
 334int 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 */
 395struct 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}
 402EXPORT_SYMBOL(host1x_syncpt_request);
 403
 404static 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        mutex_lock(&sp->host->syncpt_mutex);
 411
 412        host1x_syncpt_base_free(sp->base);
 413        kfree(sp->name);
 414        sp->base = NULL;
 415        sp->name = NULL;
 416        sp->client_managed = false;
 417
 418        mutex_unlock(&sp->host->syncpt_mutex);
 419}
 420
 421/**
 422 * host1x_syncpt_put() - free a requested syncpoint
 423 * @sp: host1x syncpoint
 424 *
 425 * Release a syncpoint previously allocated using host1x_syncpt_request(). A
 426 * host1x client driver should call this when the syncpoint is no longer in
 427 * use.
 428 */
 429void host1x_syncpt_put(struct host1x_syncpt *sp)
 430{
 431        if (!sp)
 432                return;
 433
 434        kref_put(&sp->ref, syncpt_release);
 435}
 436EXPORT_SYMBOL(host1x_syncpt_put);
 437
 438void host1x_syncpt_deinit(struct host1x *host)
 439{
 440        struct host1x_syncpt *sp = host->syncpt;
 441        unsigned int i;
 442
 443        for (i = 0; i < host->info->nb_pts; i++, sp++)
 444                kfree(sp->name);
 445}
 446
 447/**
 448 * host1x_syncpt_read_max() - read maximum syncpoint value
 449 * @sp: host1x syncpoint
 450 *
 451 * The maximum syncpoint value indicates how many operations there are in
 452 * queue, either in channel or in a software thread.
 453 */
 454u32 host1x_syncpt_read_max(struct host1x_syncpt *sp)
 455{
 456        smp_rmb();
 457
 458        return (u32)atomic_read(&sp->max_val);
 459}
 460EXPORT_SYMBOL(host1x_syncpt_read_max);
 461
 462/**
 463 * host1x_syncpt_read_min() - read minimum syncpoint value
 464 * @sp: host1x syncpoint
 465 *
 466 * The minimum syncpoint value is a shadow of the current sync point value in
 467 * hardware.
 468 */
 469u32 host1x_syncpt_read_min(struct host1x_syncpt *sp)
 470{
 471        smp_rmb();
 472
 473        return (u32)atomic_read(&sp->min_val);
 474}
 475EXPORT_SYMBOL(host1x_syncpt_read_min);
 476
 477/**
 478 * host1x_syncpt_read() - read the current syncpoint value
 479 * @sp: host1x syncpoint
 480 */
 481u32 host1x_syncpt_read(struct host1x_syncpt *sp)
 482{
 483        return host1x_syncpt_load(sp);
 484}
 485EXPORT_SYMBOL(host1x_syncpt_read);
 486
 487unsigned int host1x_syncpt_nb_pts(struct host1x *host)
 488{
 489        return host->info->nb_pts;
 490}
 491
 492unsigned int host1x_syncpt_nb_bases(struct host1x *host)
 493{
 494        return host->info->nb_bases;
 495}
 496
 497unsigned int host1x_syncpt_nb_mlocks(struct host1x *host)
 498{
 499        return host->info->nb_mlocks;
 500}
 501
 502/**
 503 * host1x_syncpt_get_by_id() - obtain a syncpoint by ID
 504 * @host: host1x controller
 505 * @id: syncpoint ID
 506 */
 507struct host1x_syncpt *host1x_syncpt_get_by_id(struct host1x *host,
 508                                              unsigned int id)
 509{
 510        if (id >= host->info->nb_pts)
 511                return NULL;
 512
 513        if (kref_get_unless_zero(&host->syncpt[id].ref))
 514                return &host->syncpt[id];
 515        else
 516                return NULL;
 517}
 518EXPORT_SYMBOL(host1x_syncpt_get_by_id);
 519
 520/**
 521 * host1x_syncpt_get_by_id_noref() - obtain a syncpoint by ID but don't
 522 *      increase the refcount.
 523 * @host: host1x controller
 524 * @id: syncpoint ID
 525 */
 526struct host1x_syncpt *host1x_syncpt_get_by_id_noref(struct host1x *host,
 527                                                    unsigned int id)
 528{
 529        if (id >= host->info->nb_pts)
 530                return NULL;
 531
 532        return &host->syncpt[id];
 533}
 534EXPORT_SYMBOL(host1x_syncpt_get_by_id_noref);
 535
 536/**
 537 * host1x_syncpt_get() - increment syncpoint refcount
 538 * @sp: syncpoint
 539 */
 540struct host1x_syncpt *host1x_syncpt_get(struct host1x_syncpt *sp)
 541{
 542        kref_get(&sp->ref);
 543
 544        return sp;
 545}
 546EXPORT_SYMBOL(host1x_syncpt_get);
 547
 548/**
 549 * host1x_syncpt_get_base() - obtain the wait base associated with a syncpoint
 550 * @sp: host1x syncpoint
 551 */
 552struct host1x_syncpt_base *host1x_syncpt_get_base(struct host1x_syncpt *sp)
 553{
 554        return sp ? sp->base : NULL;
 555}
 556EXPORT_SYMBOL(host1x_syncpt_get_base);
 557
 558/**
 559 * host1x_syncpt_base_id() - retrieve the ID of a syncpoint wait base
 560 * @base: host1x syncpoint wait base
 561 */
 562u32 host1x_syncpt_base_id(struct host1x_syncpt_base *base)
 563{
 564        return base->id;
 565}
 566EXPORT_SYMBOL(host1x_syncpt_base_id);
 567
 568static void do_nothing(struct kref *ref)
 569{
 570}
 571
 572/**
 573 * host1x_syncpt_release_vblank_reservation() - Make VBLANK syncpoint
 574 *   available for allocation
 575 *
 576 * @client: host1x bus client
 577 * @syncpt_id: syncpoint ID to make available
 578 *
 579 * Makes VBLANK<i> syncpoint available for allocatation if it was
 580 * reserved at initialization time. This should be called by the display
 581 * driver after it has ensured that any VBLANK increment programming configured
 582 * by the boot chain has been disabled.
 583 */
 584void host1x_syncpt_release_vblank_reservation(struct host1x_client *client,
 585                                              u32 syncpt_id)
 586{
 587        struct host1x *host = dev_get_drvdata(client->host->parent);
 588
 589        if (!host->info->reserve_vblank_syncpts)
 590                return;
 591
 592        kref_put(&host->syncpt[syncpt_id].ref, do_nothing);
 593}
 594EXPORT_SYMBOL(host1x_syncpt_release_vblank_reservation);
 595
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