drivers/gpu/drm/i915/intel_runtime_pm.c

   1 /*
   2  * Copyright © 2012-2014 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *    Eugeni Dodonov <eugeni.dodonov@intel.com>
  25  *    Daniel Vetter <daniel.vetter@ffwll.ch>
  26  *
  27  */
  28
  29 #include <linux/pm_runtime.h>
  30
  31 #include <drm/drm_print.h>
  32
  33 #include "i915_drv.h"
  34 #include "i915_trace.h"
  35
  36 /**
  37  * DOC: runtime pm
  38  *
  39  * The i915 driver supports dynamic enabling and disabling of entire hardware
  40  * blocks at runtime. This is especially important on the display side where
  41  * software is supposed to control many power gates manually on recent hardware,
  42  * since on the GT side a lot of the power management is done by the hardware.
  43  * But even there some manual control at the device level is required.
  44  *
  45  * Since i915 supports a diverse set of platforms with a unified codebase and
  46  * hardware engineers just love to shuffle functionality around between power
  47  * domains there's a sizeable amount of indirection required. This file provides
  48  * generic functions to the driver for grabbing and releasing references for
  49  * abstract power domains. It then maps those to the actual power wells
  50  * present for a given platform.
  51  */
  52
  53 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
  54
  55 #include <linux/sort.h>
  56
  57 #define STACKDEPTH 8
  58
  59 static noinline depot_stack_handle_t __save_depot_stack(void)
  60 {
  61         unsigned long entries[STACKDEPTH];
  62         unsigned int n;
  63
  64         n = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
  65         return stack_depot_save(entries, n, GFP_NOWAIT | __GFP_NOWARN);
  66 }
  67
  68 static void __print_depot_stack(depot_stack_handle_t stack,
  69                                 char *buf, int sz, int indent)
  70 {
  71         unsigned long *entries;
  72         unsigned int nr_entries;
  73
  74         nr_entries = stack_depot_fetch(stack, &entries);
  75         stack_trace_snprint(buf, sz, entries, nr_entries, indent);
  76 }
  77
  78 static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
  79 {
  80         spin_lock_init(&rpm->debug.lock);
  81 }
  82
  83 static noinline depot_stack_handle_t
  84 track_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
  85 {
  86         depot_stack_handle_t stack, *stacks;
  87         unsigned long flags;
  88
  89         if (!rpm->available)
  90                 return -1;
  91
  92         stack = __save_depot_stack();
  93         if (!stack)
  94                 return -1;
  95
  96         spin_lock_irqsave(&rpm->debug.lock, flags);
  97
  98         if (!rpm->debug.count)
  99                 rpm->debug.last_acquire = stack;
 100
 101         stacks = krealloc(rpm->debug.owners,
 102                           (rpm->debug.count + 1) * sizeof(*stacks),
 103                           GFP_NOWAIT | __GFP_NOWARN);
 104         if (stacks) {
 105                 stacks[rpm->debug.count++] = stack;
 106                 rpm->debug.owners = stacks;
 107         } else {
 108                 stack = -1;
 109         }
 110
 111         spin_unlock_irqrestore(&rpm->debug.lock, flags);
 112
 113         return stack;
 114 }
 115
 116 static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
 117                                              depot_stack_handle_t stack)
 118 {
 119         unsigned long flags, n;
 120         bool found = false;
 121
 122         if (unlikely(stack == -1))
 123                 return;
 124
 125         spin_lock_irqsave(&rpm->debug.lock, flags);
 126         for (n = rpm->debug.count; n--; ) {
 127                 if (rpm->debug.owners[n] == stack) {
 128                         memmove(rpm->debug.owners + n,
 129                                 rpm->debug.owners + n + 1,
 130                                 (--rpm->debug.count - n) * sizeof(stack));
 131                         found = true;
 132                         break;
 133                 }
 134         }
 135         spin_unlock_irqrestore(&rpm->debug.lock, flags);
 136
 137         if (WARN(!found,
 138                  "Unmatched wakeref (tracking %lu), count %u\n",
 139                  rpm->debug.count, atomic_read(&rpm->wakeref_count))) {
 140                 char *buf;
 141
 142                 buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN);
 143                 if (!buf)
 144                         return;
 145
 146                 __print_depot_stack(stack, buf, PAGE_SIZE, 2);
 147                 DRM_DEBUG_DRIVER("wakeref %x from\n%s", stack, buf);
 148
 149                 stack = READ_ONCE(rpm->debug.last_release);
 150                 if (stack) {
 151                         __print_depot_stack(stack, buf, PAGE_SIZE, 2);
 152                         DRM_DEBUG_DRIVER("wakeref last released at\n%s", buf);
 153                 }
 154
 155                 kfree(buf);
 156         }
 157 }
 158
 159 static int cmphandle(const void *_a, const void *_b)
 160 {
 161         const depot_stack_handle_t * const a = _a, * const b = _b;
 162
 163         if (*a < *b)
 164                 return -1;
 165         else if (*a > *b)
 166                 return 1;
 167         else
 168                 return 0;
 169 }
 170
 171 static void
 172 __print_intel_runtime_pm_wakeref(struct drm_printer *p,
 173                                  const struct intel_runtime_pm_debug *dbg)
 174 {
 175         unsigned long i;
 176         char *buf;
 177
 178         buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN);
 179         if (!buf)
 180                 return;
 181
 182         if (dbg->last_acquire) {
 183                 __print_depot_stack(dbg->last_acquire, buf, PAGE_SIZE, 2);
 184                 drm_printf(p, "Wakeref last acquired:\n%s", buf);
 185         }
 186
 187         if (dbg->last_release) {
 188                 __print_depot_stack(dbg->last_release, buf, PAGE_SIZE, 2);
 189                 drm_printf(p, "Wakeref last released:\n%s", buf);
 190         }
 191
 192         drm_printf(p, "Wakeref count: %lu\n", dbg->count);
 193
 194         sort(dbg->owners, dbg->count, sizeof(*dbg->owners), cmphandle, NULL);
 195
 196         for (i = 0; i < dbg->count; i++) {
 197                 depot_stack_handle_t stack = dbg->owners[i];
 198                 unsigned long rep;
 199
 200                 rep = 1;
 201                 while (i + 1 < dbg->count && dbg->owners[i + 1] == stack)
 202                         rep++, i++;
 203                 __print_depot_stack(stack, buf, PAGE_SIZE, 2);
 204                 drm_printf(p, "Wakeref x%lu taken at:\n%s", rep, buf);
 205         }
 206
 207         kfree(buf);
 208 }
 209
 210 static noinline void
 211 __untrack_all_wakerefs(struct intel_runtime_pm_debug *debug,
 212                        struct intel_runtime_pm_debug *saved)
 213 {
 214         *saved = *debug;
 215
 216         debug->owners = NULL;
 217         debug->count = 0;
 218         debug->last_release = __save_depot_stack();
 219 }
 220
 221 static void
 222 dump_and_free_wakeref_tracking(struct intel_runtime_pm_debug *debug)
 223 {
 224         if (debug->count) {
 225                 struct drm_printer p = drm_debug_printer("i915");
 226
 227                 __print_intel_runtime_pm_wakeref(&p, debug);
 228         }
 229
 230         kfree(debug->owners);
 231 }
 232
 233 static noinline void
 234 __intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm)
 235 {
 236         struct intel_runtime_pm_debug dbg = {};
 237         unsigned long flags;
 238
 239         if (!atomic_dec_and_lock_irqsave(&rpm->wakeref_count,
 240                                          &rpm->debug.lock,
 241                                          flags))
 242                 return;
 243
 244         __untrack_all_wakerefs(&rpm->debug, &dbg);
 245         spin_unlock_irqrestore(&rpm->debug.lock, flags);
 246
 247         dump_and_free_wakeref_tracking(&dbg);
 248 }
 249
 250 static noinline void
 251 untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm)
 252 {
 253         struct intel_runtime_pm_debug dbg = {};
 254         unsigned long flags;
 255
 256         spin_lock_irqsave(&rpm->debug.lock, flags);
 257         __untrack_all_wakerefs(&rpm->debug, &dbg);
 258         spin_unlock_irqrestore(&rpm->debug.lock, flags);
 259
 260         dump_and_free_wakeref_tracking(&dbg);
 261 }
 262
 263 void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
 264                                     struct drm_printer *p)
 265 {
 266         struct intel_runtime_pm_debug dbg = {};
 267
 268         do {
 269                 unsigned long alloc = dbg.count;
 270                 depot_stack_handle_t *s;
 271
 272                 spin_lock_irq(&rpm->debug.lock);
 273                 dbg.count = rpm->debug.count;
 274                 if (dbg.count <= alloc) {
 275                         memcpy(dbg.owners,
 276                                rpm->debug.owners,
 277                                dbg.count * sizeof(*s));
 278                 }
 279                 dbg.last_acquire = rpm->debug.last_acquire;
 280                 dbg.last_release = rpm->debug.last_release;
 281                 spin_unlock_irq(&rpm->debug.lock);
 282                 if (dbg.count <= alloc)
 283                         break;
 284
 285                 s = krealloc(dbg.owners,
 286                              dbg.count * sizeof(*s),
 287                              GFP_NOWAIT | __GFP_NOWARN);
 288                 if (!s)
 289                         goto out;
 290
 291                 dbg.owners = s;
 292         } while (1);
 293
 294         __print_intel_runtime_pm_wakeref(p, &dbg);
 295
 296 out:
 297         kfree(dbg.owners);
 298 }
 299
 300 #else
 301
 302 static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
 303 {
 304 }
 305
 306 static depot_stack_handle_t
 307 track_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
 308 {
 309         return -1;
 310 }
 311
 312 static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
 313                                              intel_wakeref_t wref)
 314 {
 315 }
 316
 317 static void
 318 __intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm)
 319 {
 320         atomic_dec(&rpm->wakeref_count);
 321 }
 322
 323 static void
 324 untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm)
 325 {
 326 }
 327
 328 #endif
 329
 330 static void
 331 intel_runtime_pm_acquire(struct intel_runtime_pm *rpm, bool wakelock)
 332 {
 333         if (wakelock) {
 334                 atomic_add(1 + INTEL_RPM_WAKELOCK_BIAS, &rpm->wakeref_count);
 335                 assert_rpm_wakelock_held(rpm);
 336         } else {
 337                 atomic_inc(&rpm->wakeref_count);
 338                 assert_rpm_raw_wakeref_held(rpm);
 339         }
 340 }
 341
 342 static void
 343 intel_runtime_pm_release(struct intel_runtime_pm *rpm, int wakelock)
 344 {
 345         if (wakelock) {
 346                 assert_rpm_wakelock_held(rpm);
 347                 atomic_sub(INTEL_RPM_WAKELOCK_BIAS, &rpm->wakeref_count);
 348         } else {
 349                 assert_rpm_raw_wakeref_held(rpm);
 350         }
 351
 352         __intel_wakeref_dec_and_check_tracking(rpm);
 353 }
 354
 355 static intel_wakeref_t __intel_runtime_pm_get(struct intel_runtime_pm *rpm,
 356                                               bool wakelock)
 357 {
 358         int ret;
 359
 360         ret = pm_runtime_get_sync(rpm->kdev);
 361         WARN_ONCE(ret < 0, "pm_runtime_get_sync() failed: %d\n", ret);
 362
 363         intel_runtime_pm_acquire(rpm, wakelock);
 364
 365         return track_intel_runtime_pm_wakeref(rpm);
 366 }
 367
 368 /**
 369  * intel_runtime_pm_get_raw - grab a raw runtime pm reference
 370  * @rpm: the intel_runtime_pm structure
 371  *
 372  * This is the unlocked version of intel_display_power_is_enabled() and should
 373  * only be used from error capture and recovery code where deadlocks are
 374  * possible.
 375  * This function grabs a device-level runtime pm reference (mostly used for
 376  * asynchronous PM management from display code) and ensures that it is powered
 377  * up. Raw references are not considered during wakelock assert checks.
 378  *
 379  * Any runtime pm reference obtained by this function must have a symmetric
 380  * call to intel_runtime_pm_put_raw() to release the reference again.
 381  *
 382  * Returns: the wakeref cookie to pass to intel_runtime_pm_put_raw(), evaluates
 383  * as True if the wakeref was acquired, or False otherwise.
 384  */
 385 intel_wakeref_t intel_runtime_pm_get_raw(struct intel_runtime_pm *rpm)
 386 {
 387         return __intel_runtime_pm_get(rpm, false);
 388 }
 389
 390 /**
 391  * intel_runtime_pm_get - grab a runtime pm reference
 392  * @rpm: the intel_runtime_pm structure
 393  *
 394  * This function grabs a device-level runtime pm reference (mostly used for GEM
 395  * code to ensure the GTT or GT is on) and ensures that it is powered up.
 396  *
 397  * Any runtime pm reference obtained by this function must have a symmetric
 398  * call to intel_runtime_pm_put() to release the reference again.
 399  *
 400  * Returns: the wakeref cookie to pass to intel_runtime_pm_put()
 401  */
 402 intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm)
 403 {
 404         return __intel_runtime_pm_get(rpm, true);
 405 }
 406
 407 /**
 408  * intel_runtime_pm_get_if_in_use - grab a runtime pm reference if device in use
 409  * @rpm: the intel_runtime_pm structure
 410  *
 411  * This function grabs a device-level runtime pm reference if the device is
 412  * already in use and ensures that it is powered up. It is illegal to try
 413  * and access the HW should intel_runtime_pm_get_if_in_use() report failure.
 414  *
 415  * Any runtime pm reference obtained by this function must have a symmetric
 416  * call to intel_runtime_pm_put() to release the reference again.
 417  *
 418  * Returns: the wakeref cookie to pass to intel_runtime_pm_put(), evaluates
 419  * as True if the wakeref was acquired, or False otherwise.
 420  */
 421 intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm)
 422 {
 423         if (IS_ENABLED(CONFIG_PM)) {
 424                 /*
 425                  * In cases runtime PM is disabled by the RPM core and we get
 426                  * an -EINVAL return value we are not supposed to call this
 427                  * function, since the power state is undefined. This applies
 428                  * atm to the late/early system suspend/resume handlers.
 429                  */
 430                 if (pm_runtime_get_if_in_use(rpm->kdev) <= 0)
 431                         return 0;
 432         }
 433
 434         intel_runtime_pm_acquire(rpm, true);
 435
 436         return track_intel_runtime_pm_wakeref(rpm);
 437 }
 438
 439 /**
 440  * intel_runtime_pm_get_noresume - grab a runtime pm reference
 441  * @rpm: the intel_runtime_pm structure
 442  *
 443  * This function grabs a device-level runtime pm reference (mostly used for GEM
 444  * code to ensure the GTT or GT is on).
 445  *
 446  * It will _not_ power up the device but instead only check that it's powered
 447  * on.  Therefore it is only valid to call this functions from contexts where
 448  * the device is known to be powered up and where trying to power it up would
 449  * result in hilarity and deadlocks. That pretty much means only the system
 450  * suspend/resume code where this is used to grab runtime pm references for
 451  * delayed setup down in work items.
 452  *
 453  * Any runtime pm reference obtained by this function must have a symmetric
 454  * call to intel_runtime_pm_put() to release the reference again.
 455  *
 456  * Returns: the wakeref cookie to pass to intel_runtime_pm_put()
 457  */
 458 intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm)
 459 {
 460         assert_rpm_wakelock_held(rpm);
 461         pm_runtime_get_noresume(rpm->kdev);
 462
 463         intel_runtime_pm_acquire(rpm, true);
 464
 465         return track_intel_runtime_pm_wakeref(rpm);
 466 }
 467
 468 static void __intel_runtime_pm_put(struct intel_runtime_pm *rpm,
 469                                    intel_wakeref_t wref,
 470                                    bool wakelock)
 471 {
 472         struct device *kdev = rpm->kdev;
 473
 474         untrack_intel_runtime_pm_wakeref(rpm, wref);
 475
 476         intel_runtime_pm_release(rpm, wakelock);
 477
 478         pm_runtime_mark_last_busy(kdev);
 479         pm_runtime_put_autosuspend(kdev);
 480 }
 481
 482 /**
 483  * intel_runtime_pm_put_raw - release a raw runtime pm reference
 484  * @rpm: the intel_runtime_pm structure
 485  * @wref: wakeref acquired for the reference that is being released
 486  *
 487  * This function drops the device-level runtime pm reference obtained by
 488  * intel_runtime_pm_get_raw() and might power down the corresponding
 489  * hardware block right away if this is the last reference.
 490  */
 491 void
 492 intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
 493 {
 494         __intel_runtime_pm_put(rpm, wref, false);
 495 }
 496
 497 /**
 498  * intel_runtime_pm_put_unchecked - release an unchecked runtime pm reference
 499  * @rpm: the intel_runtime_pm structure
 500  *
 501  * This function drops the device-level runtime pm reference obtained by
 502  * intel_runtime_pm_get() and might power down the corresponding
 503  * hardware block right away if this is the last reference.
 504  *
 505  * This function exists only for historical reasons and should be avoided in
 506  * new code, as the correctness of its use cannot be checked. Always use
 507  * intel_runtime_pm_put() instead.
 508  */
 509 void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm)
 510 {
 511         __intel_runtime_pm_put(rpm, -1, true);
 512 }
 513
 514 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
 515 /**
 516  * intel_runtime_pm_put - release a runtime pm reference
 517  * @rpm: the intel_runtime_pm structure
 518  * @wref: wakeref acquired for the reference that is being released
 519  *
 520  * This function drops the device-level runtime pm reference obtained by
 521  * intel_runtime_pm_get() and might power down the corresponding
 522  * hardware block right away if this is the last reference.
 523  */
 524 void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
 525 {
 526         __intel_runtime_pm_put(rpm, wref, true);
 527 }
 528 #endif
 529
 530 /**
 531  * intel_runtime_pm_enable - enable runtime pm
 532  * @rpm: the intel_runtime_pm structure
 533  *
 534  * This function enables runtime pm at the end of the driver load sequence.
 535  *
 536  * Note that this function does currently not enable runtime pm for the
 537  * subordinate display power domains. That is done by
 538  * intel_power_domains_enable().
 539  */
 540 void intel_runtime_pm_enable(struct intel_runtime_pm *rpm)
 541 {
 542         struct device *kdev = rpm->kdev;
 543
 544         /*
 545          * Disable the system suspend direct complete optimization, which can
 546          * leave the device suspended skipping the driver's suspend handlers
 547          * if the device was already runtime suspended. This is needed due to
 548          * the difference in our runtime and system suspend sequence and
 549          * becaue the HDA driver may require us to enable the audio power
 550          * domain during system suspend.
 551          */
 552         dev_pm_set_driver_flags(kdev, DPM_FLAG_NEVER_SKIP);
 553
 554         pm_runtime_set_autosuspend_delay(kdev, 10000); /* 10s */
 555         pm_runtime_mark_last_busy(kdev);
 556
 557         /*
 558          * Take a permanent reference to disable the RPM functionality and drop
 559          * it only when unloading the driver. Use the low level get/put helpers,
 560          * so the driver's own RPM reference tracking asserts also work on
 561          * platforms without RPM support.
 562          */
 563         if (!rpm->available) {
 564                 int ret;
 565
 566                 pm_runtime_dont_use_autosuspend(kdev);
 567                 ret = pm_runtime_get_sync(kdev);
 568                 WARN(ret < 0, "pm_runtime_get_sync() failed: %d\n", ret);
 569         } else {
 570                 pm_runtime_use_autosuspend(kdev);
 571         }
 572
 573         /*
 574          * The core calls the driver load handler with an RPM reference held.
 575          * We drop that here and will reacquire it during unloading in
 576          * intel_power_domains_fini().
 577          */
 578         pm_runtime_put_autosuspend(kdev);
 579 }
 580
 581 void intel_runtime_pm_disable(struct intel_runtime_pm *rpm)
 582 {
 583         struct device *kdev = rpm->kdev;
 584
 585         /* Transfer rpm ownership back to core */
 586         WARN(pm_runtime_get_sync(kdev) < 0,
 587              "Failed to pass rpm ownership back to core\n");
 588
 589         pm_runtime_dont_use_autosuspend(kdev);
 590
 591         if (!rpm->available)
 592                 pm_runtime_put(kdev);
 593 }
 594
 595 void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm)
 596 {
 597         int count = atomic_read(&rpm->wakeref_count);
 598
 599         WARN(count,
 600              "i915 raw-wakerefs=%d wakelocks=%d on cleanup\n",
 601              intel_rpm_raw_wakeref_count(count),
 602              intel_rpm_wakelock_count(count));
 603
 604         untrack_all_intel_runtime_pm_wakerefs(rpm);
 605 }
 606
 607 void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm)
 608 {
 609         struct drm_i915_private *i915 =
 610                         container_of(rpm, struct drm_i915_private, runtime_pm);
 611         struct pci_dev *pdev = i915->drm.pdev;
 612         struct device *kdev = &pdev->dev;
 613
 614         rpm->kdev = kdev;
 615         rpm->available = HAS_RUNTIME_PM(i915);
 616
 617         init_intel_runtime_pm_wakeref(rpm);
 618 }