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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
59static 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
68static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
69{
70 spin_lock_init(&rpm->debug.lock);
71 stack_depot_init();
72}
73
74static noinline depot_stack_handle_t
75track_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
76{
77 depot_stack_handle_t stack, *stacks;
78 unsigned long flags;
79
80 if (rpm->no_wakeref_tracking)
81 return -1;
82
83 stack = __save_depot_stack();
84 if (!stack)
85 return -1;
86
87 spin_lock_irqsave(&rpm->debug.lock, flags);
88
89 if (!rpm->debug.count)
90 rpm->debug.last_acquire = stack;
91
92 stacks = krealloc(rpm->debug.owners,
93 (rpm->debug.count + 1) * sizeof(*stacks),
94 GFP_NOWAIT | __GFP_NOWARN);
95 if (stacks) {
96 stacks[rpm->debug.count++] = stack;
97 rpm->debug.owners = stacks;
98 } else {
99 stack = -1;
100 }
101
102 spin_unlock_irqrestore(&rpm->debug.lock, flags);
103
104 return stack;
105}
106
107static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
108 depot_stack_handle_t stack)
109{
110 struct drm_i915_private *i915 = container_of(rpm,
111 struct drm_i915_private,
112 runtime_pm);
113 unsigned long flags, n;
114 bool found = false;
115
116 if (unlikely(stack == -1))
117 return;
118
119 spin_lock_irqsave(&rpm->debug.lock, flags);
120 for (n = rpm->debug.count; n--; ) {
121 if (rpm->debug.owners[n] == stack) {
122 memmove(rpm->debug.owners + n,
123 rpm->debug.owners + n + 1,
124 (--rpm->debug.count - n) * sizeof(stack));
125 found = true;
126 break;
127 }
128 }
129 spin_unlock_irqrestore(&rpm->debug.lock, flags);
130
131 if (drm_WARN(&i915->drm, !found,
132 "Unmatched wakeref (tracking %lu), count %u\n",
133 rpm->debug.count, atomic_read(&rpm->wakeref_count))) {
134 char *buf;
135
136 buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN);
137 if (!buf)
138 return;
139
140 stack_depot_snprint(stack, buf, PAGE_SIZE, 2);
141 DRM_DEBUG_DRIVER("wakeref %x from\n%s", stack, buf);
142
143 stack = READ_ONCE(rpm->debug.last_release);
144 if (stack) {
145 stack_depot_snprint(stack, buf, PAGE_SIZE, 2);
146 DRM_DEBUG_DRIVER("wakeref last released at\n%s", buf);
147 }
148
149 kfree(buf);
150 }
151}
152
153static int cmphandle(const void *_a, const void *_b)
154{
155 const depot_stack_handle_t * const a = _a, * const b = _b;
156
157 if (*a < *b)
158 return -1;
159 else if (*a > *b)
160 return 1;
161 else
162 return 0;
163}
164
165static void
166__print_intel_runtime_pm_wakeref(struct drm_printer *p,
167 const struct intel_runtime_pm_debug *dbg)
168{
169 unsigned long i;
170 char *buf;
171
172 buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN);
173 if (!buf)
174 return;
175
176 if (dbg->last_acquire) {
177 stack_depot_snprint(dbg->last_acquire, buf, PAGE_SIZE, 2);
178 drm_printf(p, "Wakeref last acquired:\n%s", buf);
179 }
180
181 if (dbg->last_release) {
182 stack_depot_snprint(dbg->last_release, buf, PAGE_SIZE, 2);
183 drm_printf(p, "Wakeref last released:\n%s", buf);
184 }
185
186 drm_printf(p, "Wakeref count: %lu\n", dbg->count);
187
188 sort(dbg->owners, dbg->count, sizeof(*dbg->owners), cmphandle, NULL);
189
190 for (i = 0; i < dbg->count; i++) {
191 depot_stack_handle_t stack = dbg->owners[i];
192 unsigned long rep;
193
194 rep = 1;
195 while (i + 1 < dbg->count && dbg->owners[i + 1] == stack)
196 rep++, i++;
197 stack_depot_snprint(stack, buf, PAGE_SIZE, 2);
198 drm_printf(p, "Wakeref x%lu taken at:\n%s", rep, buf);
199 }
200
201 kfree(buf);
202}
203
204static noinline void
205__untrack_all_wakerefs(struct intel_runtime_pm_debug *debug,
206 struct intel_runtime_pm_debug *saved)
207{
208 *saved = *debug;
209
210 debug->owners = NULL;
211 debug->count = 0;
212 debug->last_release = __save_depot_stack();
213}
214
215static void
216dump_and_free_wakeref_tracking(struct intel_runtime_pm_debug *debug)
217{
218 if (debug->count) {
219 struct drm_printer p = drm_debug_printer("i915");
220
221 __print_intel_runtime_pm_wakeref(&p, debug);
222 }
223
224 kfree(debug->owners);
225}
226
227static noinline void
228__intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm)
229{
230 struct intel_runtime_pm_debug dbg = {};
231 unsigned long flags;
232
233 if (!atomic_dec_and_lock_irqsave(&rpm->wakeref_count,
234 &rpm->debug.lock,
235 flags))
236 return;
237
238 __untrack_all_wakerefs(&rpm->debug, &dbg);
239 spin_unlock_irqrestore(&rpm->debug.lock, flags);
240
241 dump_and_free_wakeref_tracking(&dbg);
242}
243
244static noinline void
245untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm)
246{
247 struct intel_runtime_pm_debug dbg = {};
248 unsigned long flags;
249
250 spin_lock_irqsave(&rpm->debug.lock, flags);
251 __untrack_all_wakerefs(&rpm->debug, &dbg);
252 spin_unlock_irqrestore(&rpm->debug.lock, flags);
253
254 dump_and_free_wakeref_tracking(&dbg);
255}
256
257void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
258 struct drm_printer *p)
259{
260 struct intel_runtime_pm_debug dbg = {};
261
262 do {
263 unsigned long alloc = dbg.count;
264 depot_stack_handle_t *s;
265
266 spin_lock_irq(&rpm->debug.lock);
267 dbg.count = rpm->debug.count;
268 if (dbg.count <= alloc) {
269 memcpy(dbg.owners,
270 rpm->debug.owners,
271 dbg.count * sizeof(*s));
272 }
273 dbg.last_acquire = rpm->debug.last_acquire;
274 dbg.last_release = rpm->debug.last_release;
275 spin_unlock_irq(&rpm->debug.lock);
276 if (dbg.count <= alloc)
277 break;
278
279 s = krealloc(dbg.owners,
280 dbg.count * sizeof(*s),
281 GFP_NOWAIT | __GFP_NOWARN);
282 if (!s)
283 goto out;
284
285 dbg.owners = s;
286 } while (1);
287
288 __print_intel_runtime_pm_wakeref(p, &dbg);
289
290out:
291 kfree(dbg.owners);
292}
293
294#else
295
296static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
297{
298}
299
300static depot_stack_handle_t
301track_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
302{
303 return -1;
304}
305
306static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
307 intel_wakeref_t wref)
308{
309}
310
311static void
312__intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm)
313{
314 atomic_dec(&rpm->wakeref_count);
315}
316
317static void
318untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm)
319{
320}
321
322#endif
323
324static void
325intel_runtime_pm_acquire(struct intel_runtime_pm *rpm, bool wakelock)
326{
327 if (wakelock) {
328 atomic_add(1 + INTEL_RPM_WAKELOCK_BIAS, &rpm->wakeref_count);
329 assert_rpm_wakelock_held(rpm);
330 } else {
331 atomic_inc(&rpm->wakeref_count);
332 assert_rpm_raw_wakeref_held(rpm);
333 }
334}
335
336static void
337intel_runtime_pm_release(struct intel_runtime_pm *rpm, int wakelock)
338{
339 if (wakelock) {
340 assert_rpm_wakelock_held(rpm);
341 atomic_sub(INTEL_RPM_WAKELOCK_BIAS, &rpm->wakeref_count);
342 } else {
343 assert_rpm_raw_wakeref_held(rpm);
344 }
345
346 __intel_wakeref_dec_and_check_tracking(rpm);
347}
348
349static intel_wakeref_t __intel_runtime_pm_get(struct intel_runtime_pm *rpm,
350 bool wakelock)
351{
352 struct drm_i915_private *i915 = container_of(rpm,
353 struct drm_i915_private,
354 runtime_pm);
355 int ret;
356
357 ret = pm_runtime_get_sync(rpm->kdev);
358 drm_WARN_ONCE(&i915->drm, ret < 0,
359 "pm_runtime_get_sync() failed: %d\n", ret);
360
361 intel_runtime_pm_acquire(rpm, wakelock);
362
363 return track_intel_runtime_pm_wakeref(rpm);
364}
365
366/**
367 * intel_runtime_pm_get_raw - grab a raw runtime pm reference
368 * @rpm: the intel_runtime_pm structure
369 *
370 * This is the unlocked version of intel_display_power_is_enabled() and should
371 * only be used from error capture and recovery code where deadlocks are
372 * possible.
373 * This function grabs a device-level runtime pm reference (mostly used for
374 * asynchronous PM management from display code) and ensures that it is powered
375 * up. Raw references are not considered during wakelock assert checks.
376 *
377 * Any runtime pm reference obtained by this function must have a symmetric
378 * call to intel_runtime_pm_put_raw() to release the reference again.
379 *
380 * Returns: the wakeref cookie to pass to intel_runtime_pm_put_raw(), evaluates
381 * as True if the wakeref was acquired, or False otherwise.
382 */
383intel_wakeref_t intel_runtime_pm_get_raw(struct intel_runtime_pm *rpm)
384{
385 return __intel_runtime_pm_get(rpm, false);
386}
387
388/**
389 * intel_runtime_pm_get - grab a runtime pm reference
390 * @rpm: the intel_runtime_pm structure
391 *
392 * This function grabs a device-level runtime pm reference (mostly used for GEM
393 * code to ensure the GTT or GT is on) and ensures that it is powered up.
394 *
395 * Any runtime pm reference obtained by this function must have a symmetric
396 * call to intel_runtime_pm_put() to release the reference again.
397 *
398 * Returns: the wakeref cookie to pass to intel_runtime_pm_put()
399 */
400intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm)
401{
402 return __intel_runtime_pm_get(rpm, true);
403}
404
405/**
406 * __intel_runtime_pm_get_if_active - grab a runtime pm reference if device is active
407 * @rpm: the intel_runtime_pm structure
408 * @ignore_usecount: get a ref even if dev->power.usage_count is 0
409 *
410 * This function grabs a device-level runtime pm reference if the device is
411 * already active and ensures that it is powered up. It is illegal to try
412 * and access the HW should intel_runtime_pm_get_if_active() report failure.
413 *
414 * If @ignore_usecount is true, a reference will be acquired even if there is no
415 * user requiring the device to be powered up (dev->power.usage_count == 0).
416 * If the function returns false in this case then it's guaranteed that the
417 * device's runtime suspend hook has been called already or that it will be
418 * called (and hence it's also guaranteed that the device's runtime resume
419 * hook will be called eventually).
420 *
421 * Any runtime pm reference obtained by this function must have a symmetric
422 * call to intel_runtime_pm_put() to release the reference again.
423 *
424 * Returns: the wakeref cookie to pass to intel_runtime_pm_put(), evaluates
425 * as True if the wakeref was acquired, or False otherwise.
426 */
427static intel_wakeref_t __intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm,
428 bool ignore_usecount)
429{
430 if (IS_ENABLED(CONFIG_PM)) {
431 /*
432 * In cases runtime PM is disabled by the RPM core and we get
433 * an -EINVAL return value we are not supposed to call this
434 * function, since the power state is undefined. This applies
435 * atm to the late/early system suspend/resume handlers.
436 */
437 if (pm_runtime_get_if_active(rpm->kdev, ignore_usecount) <= 0)
438 return 0;
439 }
440
441 intel_runtime_pm_acquire(rpm, true);
442
443 return track_intel_runtime_pm_wakeref(rpm);
444}
445
446intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm)
447{
448 return __intel_runtime_pm_get_if_active(rpm, false);
449}
450
451intel_wakeref_t intel_runtime_pm_get_if_active(struct intel_runtime_pm *rpm)
452{
453 return __intel_runtime_pm_get_if_active(rpm, true);
454}
455
456/**
457 * intel_runtime_pm_get_noresume - grab a runtime pm reference
458 * @rpm: the intel_runtime_pm structure
459 *
460 * This function grabs a device-level runtime pm reference (mostly used for GEM
461 * code to ensure the GTT or GT is on).
462 *
463 * It will _not_ power up the device but instead only check that it's powered
464 * on. Therefore it is only valid to call this functions from contexts where
465 * the device is known to be powered up and where trying to power it up would
466 * result in hilarity and deadlocks. That pretty much means only the system
467 * suspend/resume code where this is used to grab runtime pm references for
468 * delayed setup down in work items.
469 *
470 * Any runtime pm reference obtained by this function must have a symmetric
471 * call to intel_runtime_pm_put() to release the reference again.
472 *
473 * Returns: the wakeref cookie to pass to intel_runtime_pm_put()
474 */
475intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm)
476{
477 assert_rpm_wakelock_held(rpm);
478 pm_runtime_get_noresume(rpm->kdev);
479
480 intel_runtime_pm_acquire(rpm, true);
481
482 return track_intel_runtime_pm_wakeref(rpm);
483}
484
485static void __intel_runtime_pm_put(struct intel_runtime_pm *rpm,
486 intel_wakeref_t wref,
487 bool wakelock)
488{
489 struct device *kdev = rpm->kdev;
490
491 untrack_intel_runtime_pm_wakeref(rpm, wref);
492
493 intel_runtime_pm_release(rpm, wakelock);
494
495 pm_runtime_mark_last_busy(kdev);
496 pm_runtime_put_autosuspend(kdev);
497}
498
499/**
500 * intel_runtime_pm_put_raw - release a raw runtime pm reference
501 * @rpm: the intel_runtime_pm structure
502 * @wref: wakeref acquired for the reference that is being released
503 *
504 * This function drops the device-level runtime pm reference obtained by
505 * intel_runtime_pm_get_raw() and might power down the corresponding
506 * hardware block right away if this is the last reference.
507 */
508void
509intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
510{
511 __intel_runtime_pm_put(rpm, wref, false);
512}
513
514/**
515 * intel_runtime_pm_put_unchecked - release an unchecked runtime pm reference
516 * @rpm: the intel_runtime_pm structure
517 *
518 * This function drops the device-level runtime pm reference obtained by
519 * intel_runtime_pm_get() and might power down the corresponding
520 * hardware block right away if this is the last reference.
521 *
522 * This function exists only for historical reasons and should be avoided in
523 * new code, as the correctness of its use cannot be checked. Always use
524 * intel_runtime_pm_put() instead.
525 */
526void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm)
527{
528 __intel_runtime_pm_put(rpm, -1, true);
529}
530
531#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
532/**
533 * intel_runtime_pm_put - release a runtime pm reference
534 * @rpm: the intel_runtime_pm structure
535 * @wref: wakeref acquired for the reference that is being released
536 *
537 * This function drops the device-level runtime pm reference obtained by
538 * intel_runtime_pm_get() and might power down the corresponding
539 * hardware block right away if this is the last reference.
540 */
541void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
542{
543 __intel_runtime_pm_put(rpm, wref, true);
544}
545#endif
546
547/**
548 * intel_runtime_pm_enable - enable runtime pm
549 * @rpm: the intel_runtime_pm structure
550 *
551 * This function enables runtime pm at the end of the driver load sequence.
552 *
553 * Note that this function does currently not enable runtime pm for the
554 * subordinate display power domains. That is done by
555 * intel_power_domains_enable().
556 */
557void intel_runtime_pm_enable(struct intel_runtime_pm *rpm)
558{
559 struct drm_i915_private *i915 = container_of(rpm,
560 struct drm_i915_private,
561 runtime_pm);
562 struct device *kdev = rpm->kdev;
563
564 /*
565 * Disable the system suspend direct complete optimization, which can
566 * leave the device suspended skipping the driver's suspend handlers
567 * if the device was already runtime suspended. This is needed due to
568 * the difference in our runtime and system suspend sequence and
569 * becaue the HDA driver may require us to enable the audio power
570 * domain during system suspend.
571 */
572 dev_pm_set_driver_flags(kdev, DPM_FLAG_NO_DIRECT_COMPLETE);
573
574 pm_runtime_set_autosuspend_delay(kdev, 10000); /* 10s */
575 pm_runtime_mark_last_busy(kdev);
576
577 /*
578 * Take a permanent reference to disable the RPM functionality and drop
579 * it only when unloading the driver. Use the low level get/put helpers,
580 * so the driver's own RPM reference tracking asserts also work on
581 * platforms without RPM support.
582 */
583 if (!rpm->available) {
584 int ret;
585
586 pm_runtime_dont_use_autosuspend(kdev);
587 ret = pm_runtime_get_sync(kdev);
588 drm_WARN(&i915->drm, ret < 0,
589 "pm_runtime_get_sync() failed: %d\n", ret);
590 } else {
591 pm_runtime_use_autosuspend(kdev);
592 }
593
594 /*
595 * FIXME: Temp hammer to keep autosupend disable on lmem supported platforms.
596 * As per PCIe specs 5.3.1.4.1, all iomem read write request over a PCIe
597 * function will be unsupported in case PCIe endpoint function is in D3.
598 * Let's keep i915 autosuspend control 'on' till we fix all known issue
599 * with lmem access in D3.
600 */
601 if (!IS_DGFX(i915))
602 pm_runtime_allow(kdev);
603
604 /*
605 * The core calls the driver load handler with an RPM reference held.
606 * We drop that here and will reacquire it during unloading in
607 * intel_power_domains_fini().
608 */
609 pm_runtime_put_autosuspend(kdev);
610}
611
612void intel_runtime_pm_disable(struct intel_runtime_pm *rpm)
613{
614 struct drm_i915_private *i915 = container_of(rpm,
615 struct drm_i915_private,
616 runtime_pm);
617 struct device *kdev = rpm->kdev;
618
619 /* Transfer rpm ownership back to core */
620 drm_WARN(&i915->drm, pm_runtime_get_sync(kdev) < 0,
621 "Failed to pass rpm ownership back to core\n");
622
623 pm_runtime_dont_use_autosuspend(kdev);
624
625 if (!rpm->available)
626 pm_runtime_put(kdev);
627}
628
629void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm)
630{
631 struct drm_i915_private *i915 = container_of(rpm,
632 struct drm_i915_private,
633 runtime_pm);
634 int count = atomic_read(&rpm->wakeref_count);
635
636 intel_wakeref_auto_fini(&rpm->userfault_wakeref);
637
638 drm_WARN(&i915->drm, count,
639 "i915 raw-wakerefs=%d wakelocks=%d on cleanup\n",
640 intel_rpm_raw_wakeref_count(count),
641 intel_rpm_wakelock_count(count));
642
643 untrack_all_intel_runtime_pm_wakerefs(rpm);
644}
645
646void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm)
647{
648 struct drm_i915_private *i915 =
649 container_of(rpm, struct drm_i915_private, runtime_pm);
650 struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
651 struct device *kdev = &pdev->dev;
652
653 rpm->kdev = kdev;
654 rpm->available = HAS_RUNTIME_PM(i915);
655
656 init_intel_runtime_pm_wakeref(rpm);
657 INIT_LIST_HEAD(&rpm->lmem_userfault_list);
658 spin_lock_init(&rpm->lmem_userfault_lock);
659 intel_wakeref_auto_init(&rpm->userfault_wakeref, rpm);
660}