drm/i915: Fix docbook header for __intel_runtime_pm_get_if_active()
[linux-2.6-microblaze.git] / 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         struct drm_i915_private *i915 = container_of(rpm,
120                                                      struct drm_i915_private,
121                                                      runtime_pm);
122         unsigned long flags, n;
123         bool found = false;
124
125         if (unlikely(stack == -1))
126                 return;
127
128         spin_lock_irqsave(&rpm->debug.lock, flags);
129         for (n = rpm->debug.count; n--; ) {
130                 if (rpm->debug.owners[n] == stack) {
131                         memmove(rpm->debug.owners + n,
132                                 rpm->debug.owners + n + 1,
133                                 (--rpm->debug.count - n) * sizeof(stack));
134                         found = true;
135                         break;
136                 }
137         }
138         spin_unlock_irqrestore(&rpm->debug.lock, flags);
139
140         if (drm_WARN(&i915->drm, !found,
141                      "Unmatched wakeref (tracking %lu), count %u\n",
142                      rpm->debug.count, atomic_read(&rpm->wakeref_count))) {
143                 char *buf;
144
145                 buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN);
146                 if (!buf)
147                         return;
148
149                 __print_depot_stack(stack, buf, PAGE_SIZE, 2);
150                 DRM_DEBUG_DRIVER("wakeref %x from\n%s", stack, buf);
151
152                 stack = READ_ONCE(rpm->debug.last_release);
153                 if (stack) {
154                         __print_depot_stack(stack, buf, PAGE_SIZE, 2);
155                         DRM_DEBUG_DRIVER("wakeref last released at\n%s", buf);
156                 }
157
158                 kfree(buf);
159         }
160 }
161
162 static int cmphandle(const void *_a, const void *_b)
163 {
164         const depot_stack_handle_t * const a = _a, * const b = _b;
165
166         if (*a < *b)
167                 return -1;
168         else if (*a > *b)
169                 return 1;
170         else
171                 return 0;
172 }
173
174 static void
175 __print_intel_runtime_pm_wakeref(struct drm_printer *p,
176                                  const struct intel_runtime_pm_debug *dbg)
177 {
178         unsigned long i;
179         char *buf;
180
181         buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN);
182         if (!buf)
183                 return;
184
185         if (dbg->last_acquire) {
186                 __print_depot_stack(dbg->last_acquire, buf, PAGE_SIZE, 2);
187                 drm_printf(p, "Wakeref last acquired:\n%s", buf);
188         }
189
190         if (dbg->last_release) {
191                 __print_depot_stack(dbg->last_release, buf, PAGE_SIZE, 2);
192                 drm_printf(p, "Wakeref last released:\n%s", buf);
193         }
194
195         drm_printf(p, "Wakeref count: %lu\n", dbg->count);
196
197         sort(dbg->owners, dbg->count, sizeof(*dbg->owners), cmphandle, NULL);
198
199         for (i = 0; i < dbg->count; i++) {
200                 depot_stack_handle_t stack = dbg->owners[i];
201                 unsigned long rep;
202
203                 rep = 1;
204                 while (i + 1 < dbg->count && dbg->owners[i + 1] == stack)
205                         rep++, i++;
206                 __print_depot_stack(stack, buf, PAGE_SIZE, 2);
207                 drm_printf(p, "Wakeref x%lu taken at:\n%s", rep, buf);
208         }
209
210         kfree(buf);
211 }
212
213 static noinline void
214 __untrack_all_wakerefs(struct intel_runtime_pm_debug *debug,
215                        struct intel_runtime_pm_debug *saved)
216 {
217         *saved = *debug;
218
219         debug->owners = NULL;
220         debug->count = 0;
221         debug->last_release = __save_depot_stack();
222 }
223
224 static void
225 dump_and_free_wakeref_tracking(struct intel_runtime_pm_debug *debug)
226 {
227         if (debug->count) {
228                 struct drm_printer p = drm_debug_printer("i915");
229
230                 __print_intel_runtime_pm_wakeref(&p, debug);
231         }
232
233         kfree(debug->owners);
234 }
235
236 static noinline void
237 __intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm)
238 {
239         struct intel_runtime_pm_debug dbg = {};
240         unsigned long flags;
241
242         if (!atomic_dec_and_lock_irqsave(&rpm->wakeref_count,
243                                          &rpm->debug.lock,
244                                          flags))
245                 return;
246
247         __untrack_all_wakerefs(&rpm->debug, &dbg);
248         spin_unlock_irqrestore(&rpm->debug.lock, flags);
249
250         dump_and_free_wakeref_tracking(&dbg);
251 }
252
253 static noinline void
254 untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm)
255 {
256         struct intel_runtime_pm_debug dbg = {};
257         unsigned long flags;
258
259         spin_lock_irqsave(&rpm->debug.lock, flags);
260         __untrack_all_wakerefs(&rpm->debug, &dbg);
261         spin_unlock_irqrestore(&rpm->debug.lock, flags);
262
263         dump_and_free_wakeref_tracking(&dbg);
264 }
265
266 void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
267                                     struct drm_printer *p)
268 {
269         struct intel_runtime_pm_debug dbg = {};
270
271         do {
272                 unsigned long alloc = dbg.count;
273                 depot_stack_handle_t *s;
274
275                 spin_lock_irq(&rpm->debug.lock);
276                 dbg.count = rpm->debug.count;
277                 if (dbg.count <= alloc) {
278                         memcpy(dbg.owners,
279                                rpm->debug.owners,
280                                dbg.count * sizeof(*s));
281                 }
282                 dbg.last_acquire = rpm->debug.last_acquire;
283                 dbg.last_release = rpm->debug.last_release;
284                 spin_unlock_irq(&rpm->debug.lock);
285                 if (dbg.count <= alloc)
286                         break;
287
288                 s = krealloc(dbg.owners,
289                              dbg.count * sizeof(*s),
290                              GFP_NOWAIT | __GFP_NOWARN);
291                 if (!s)
292                         goto out;
293
294                 dbg.owners = s;
295         } while (1);
296
297         __print_intel_runtime_pm_wakeref(p, &dbg);
298
299 out:
300         kfree(dbg.owners);
301 }
302
303 #else
304
305 static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
306 {
307 }
308
309 static depot_stack_handle_t
310 track_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
311 {
312         return -1;
313 }
314
315 static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
316                                              intel_wakeref_t wref)
317 {
318 }
319
320 static void
321 __intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm)
322 {
323         atomic_dec(&rpm->wakeref_count);
324 }
325
326 static void
327 untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm)
328 {
329 }
330
331 #endif
332
333 static void
334 intel_runtime_pm_acquire(struct intel_runtime_pm *rpm, bool wakelock)
335 {
336         if (wakelock) {
337                 atomic_add(1 + INTEL_RPM_WAKELOCK_BIAS, &rpm->wakeref_count);
338                 assert_rpm_wakelock_held(rpm);
339         } else {
340                 atomic_inc(&rpm->wakeref_count);
341                 assert_rpm_raw_wakeref_held(rpm);
342         }
343 }
344
345 static void
346 intel_runtime_pm_release(struct intel_runtime_pm *rpm, int wakelock)
347 {
348         if (wakelock) {
349                 assert_rpm_wakelock_held(rpm);
350                 atomic_sub(INTEL_RPM_WAKELOCK_BIAS, &rpm->wakeref_count);
351         } else {
352                 assert_rpm_raw_wakeref_held(rpm);
353         }
354
355         __intel_wakeref_dec_and_check_tracking(rpm);
356 }
357
358 static intel_wakeref_t __intel_runtime_pm_get(struct intel_runtime_pm *rpm,
359                                               bool wakelock)
360 {
361         struct drm_i915_private *i915 = container_of(rpm,
362                                                      struct drm_i915_private,
363                                                      runtime_pm);
364         int ret;
365
366         ret = pm_runtime_get_sync(rpm->kdev);
367         drm_WARN_ONCE(&i915->drm, ret < 0,
368                       "pm_runtime_get_sync() failed: %d\n", ret);
369
370         intel_runtime_pm_acquire(rpm, wakelock);
371
372         return track_intel_runtime_pm_wakeref(rpm);
373 }
374
375 /**
376  * intel_runtime_pm_get_raw - grab a raw runtime pm reference
377  * @rpm: the intel_runtime_pm structure
378  *
379  * This is the unlocked version of intel_display_power_is_enabled() and should
380  * only be used from error capture and recovery code where deadlocks are
381  * possible.
382  * This function grabs a device-level runtime pm reference (mostly used for
383  * asynchronous PM management from display code) and ensures that it is powered
384  * up. Raw references are not considered during wakelock assert checks.
385  *
386  * Any runtime pm reference obtained by this function must have a symmetric
387  * call to intel_runtime_pm_put_raw() to release the reference again.
388  *
389  * Returns: the wakeref cookie to pass to intel_runtime_pm_put_raw(), evaluates
390  * as True if the wakeref was acquired, or False otherwise.
391  */
392 intel_wakeref_t intel_runtime_pm_get_raw(struct intel_runtime_pm *rpm)
393 {
394         return __intel_runtime_pm_get(rpm, false);
395 }
396
397 /**
398  * intel_runtime_pm_get - grab a runtime pm reference
399  * @rpm: the intel_runtime_pm structure
400  *
401  * This function grabs a device-level runtime pm reference (mostly used for GEM
402  * code to ensure the GTT or GT is on) and ensures that it is powered up.
403  *
404  * Any runtime pm reference obtained by this function must have a symmetric
405  * call to intel_runtime_pm_put() to release the reference again.
406  *
407  * Returns: the wakeref cookie to pass to intel_runtime_pm_put()
408  */
409 intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm)
410 {
411         return __intel_runtime_pm_get(rpm, true);
412 }
413
414 /**
415  * __intel_runtime_pm_get_if_active - grab a runtime pm reference if device is active
416  * @rpm: the intel_runtime_pm structure
417  * @ignore_usecount: get a ref even if dev->power.usage_count is 0
418  *
419  * This function grabs a device-level runtime pm reference if the device is
420  * already active and ensures that it is powered up. It is illegal to try
421  * and access the HW should intel_runtime_pm_get_if_active() report failure.
422  *
423  * If @ignore_usecount is true, a reference will be acquired even if there is no
424  * user requiring the device to be powered up (dev->power.usage_count == 0).
425  * If the function returns false in this case then it's guaranteed that the
426  * device's runtime suspend hook has been called already or that it will be
427  * called (and hence it's also guaranteed that the device's runtime resume
428  * hook will be called eventually).
429  *
430  * Any runtime pm reference obtained by this function must have a symmetric
431  * call to intel_runtime_pm_put() to release the reference again.
432  *
433  * Returns: the wakeref cookie to pass to intel_runtime_pm_put(), evaluates
434  * as True if the wakeref was acquired, or False otherwise.
435  */
436 static intel_wakeref_t __intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm,
437                                                         bool ignore_usecount)
438 {
439         if (IS_ENABLED(CONFIG_PM)) {
440                 /*
441                  * In cases runtime PM is disabled by the RPM core and we get
442                  * an -EINVAL return value we are not supposed to call this
443                  * function, since the power state is undefined. This applies
444                  * atm to the late/early system suspend/resume handlers.
445                  */
446                 if (pm_runtime_get_if_active(rpm->kdev, ignore_usecount) <= 0)
447                         return 0;
448         }
449
450         intel_runtime_pm_acquire(rpm, true);
451
452         return track_intel_runtime_pm_wakeref(rpm);
453 }
454
455 intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm)
456 {
457         return __intel_runtime_pm_get_if_active(rpm, false);
458 }
459
460 intel_wakeref_t intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm)
461 {
462         return __intel_runtime_pm_get_if_active(rpm, true);
463 }
464
465 /**
466  * intel_runtime_pm_get_noresume - grab a runtime pm reference
467  * @rpm: the intel_runtime_pm structure
468  *
469  * This function grabs a device-level runtime pm reference (mostly used for GEM
470  * code to ensure the GTT or GT is on).
471  *
472  * It will _not_ power up the device but instead only check that it's powered
473  * on.  Therefore it is only valid to call this functions from contexts where
474  * the device is known to be powered up and where trying to power it up would
475  * result in hilarity and deadlocks. That pretty much means only the system
476  * suspend/resume code where this is used to grab runtime pm references for
477  * delayed setup down in work items.
478  *
479  * Any runtime pm reference obtained by this function must have a symmetric
480  * call to intel_runtime_pm_put() to release the reference again.
481  *
482  * Returns: the wakeref cookie to pass to intel_runtime_pm_put()
483  */
484 intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm)
485 {
486         assert_rpm_wakelock_held(rpm);
487         pm_runtime_get_noresume(rpm->kdev);
488
489         intel_runtime_pm_acquire(rpm, true);
490
491         return track_intel_runtime_pm_wakeref(rpm);
492 }
493
494 static void __intel_runtime_pm_put(struct intel_runtime_pm *rpm,
495                                    intel_wakeref_t wref,
496                                    bool wakelock)
497 {
498         struct device *kdev = rpm->kdev;
499
500         untrack_intel_runtime_pm_wakeref(rpm, wref);
501
502         intel_runtime_pm_release(rpm, wakelock);
503
504         pm_runtime_mark_last_busy(kdev);
505         pm_runtime_put_autosuspend(kdev);
506 }
507
508 /**
509  * intel_runtime_pm_put_raw - release a raw runtime pm reference
510  * @rpm: the intel_runtime_pm structure
511  * @wref: wakeref acquired for the reference that is being released
512  *
513  * This function drops the device-level runtime pm reference obtained by
514  * intel_runtime_pm_get_raw() and might power down the corresponding
515  * hardware block right away if this is the last reference.
516  */
517 void
518 intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
519 {
520         __intel_runtime_pm_put(rpm, wref, false);
521 }
522
523 /**
524  * intel_runtime_pm_put_unchecked - release an unchecked runtime pm reference
525  * @rpm: the intel_runtime_pm structure
526  *
527  * This function drops the device-level runtime pm reference obtained by
528  * intel_runtime_pm_get() and might power down the corresponding
529  * hardware block right away if this is the last reference.
530  *
531  * This function exists only for historical reasons and should be avoided in
532  * new code, as the correctness of its use cannot be checked. Always use
533  * intel_runtime_pm_put() instead.
534  */
535 void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm)
536 {
537         __intel_runtime_pm_put(rpm, -1, true);
538 }
539
540 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
541 /**
542  * intel_runtime_pm_put - release a runtime pm reference
543  * @rpm: the intel_runtime_pm structure
544  * @wref: wakeref acquired for the reference that is being released
545  *
546  * This function drops the device-level runtime pm reference obtained by
547  * intel_runtime_pm_get() and might power down the corresponding
548  * hardware block right away if this is the last reference.
549  */
550 void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
551 {
552         __intel_runtime_pm_put(rpm, wref, true);
553 }
554 #endif
555
556 /**
557  * intel_runtime_pm_enable - enable runtime pm
558  * @rpm: the intel_runtime_pm structure
559  *
560  * This function enables runtime pm at the end of the driver load sequence.
561  *
562  * Note that this function does currently not enable runtime pm for the
563  * subordinate display power domains. That is done by
564  * intel_power_domains_enable().
565  */
566 void intel_runtime_pm_enable(struct intel_runtime_pm *rpm)
567 {
568         struct drm_i915_private *i915 = container_of(rpm,
569                                                      struct drm_i915_private,
570                                                      runtime_pm);
571         struct device *kdev = rpm->kdev;
572
573         /*
574          * Disable the system suspend direct complete optimization, which can
575          * leave the device suspended skipping the driver's suspend handlers
576          * if the device was already runtime suspended. This is needed due to
577          * the difference in our runtime and system suspend sequence and
578          * becaue the HDA driver may require us to enable the audio power
579          * domain during system suspend.
580          */
581         dev_pm_set_driver_flags(kdev, DPM_FLAG_NO_DIRECT_COMPLETE);
582
583         pm_runtime_set_autosuspend_delay(kdev, 10000); /* 10s */
584         pm_runtime_mark_last_busy(kdev);
585
586         /*
587          * Take a permanent reference to disable the RPM functionality and drop
588          * it only when unloading the driver. Use the low level get/put helpers,
589          * so the driver's own RPM reference tracking asserts also work on
590          * platforms without RPM support.
591          */
592         if (!rpm->available) {
593                 int ret;
594
595                 pm_runtime_dont_use_autosuspend(kdev);
596                 ret = pm_runtime_get_sync(kdev);
597                 drm_WARN(&i915->drm, ret < 0,
598                          "pm_runtime_get_sync() failed: %d\n", ret);
599         } else {
600                 pm_runtime_use_autosuspend(kdev);
601         }
602
603         /*
604          * The core calls the driver load handler with an RPM reference held.
605          * We drop that here and will reacquire it during unloading in
606          * intel_power_domains_fini().
607          */
608         pm_runtime_put_autosuspend(kdev);
609 }
610
611 void intel_runtime_pm_disable(struct intel_runtime_pm *rpm)
612 {
613         struct drm_i915_private *i915 = container_of(rpm,
614                                                      struct drm_i915_private,
615                                                      runtime_pm);
616         struct device *kdev = rpm->kdev;
617
618         /* Transfer rpm ownership back to core */
619         drm_WARN(&i915->drm, pm_runtime_get_sync(kdev) < 0,
620                  "Failed to pass rpm ownership back to core\n");
621
622         pm_runtime_dont_use_autosuspend(kdev);
623
624         if (!rpm->available)
625                 pm_runtime_put(kdev);
626 }
627
628 void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm)
629 {
630         struct drm_i915_private *i915 = container_of(rpm,
631                                                      struct drm_i915_private,
632                                                      runtime_pm);
633         int count = atomic_read(&rpm->wakeref_count);
634
635         drm_WARN(&i915->drm, count,
636                  "i915 raw-wakerefs=%d wakelocks=%d on cleanup\n",
637                  intel_rpm_raw_wakeref_count(count),
638                  intel_rpm_wakelock_count(count));
639
640         untrack_all_intel_runtime_pm_wakerefs(rpm);
641 }
642
643 void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm)
644 {
645         struct drm_i915_private *i915 =
646                         container_of(rpm, struct drm_i915_private, runtime_pm);
647         struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
648         struct device *kdev = &pdev->dev;
649
650         rpm->kdev = kdev;
651         rpm->available = HAS_RUNTIME_PM(i915);
652
653         init_intel_runtime_pm_wakeref(rpm);
654 }