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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#include <linux/vgaarb.h>
31
32#include <drm/drm_print.h>
33
34#include "i915_drv.h"
35#include "i915_trace.h"
36
37/**
38 * DOC: runtime pm
39 *
40 * The i915 driver supports dynamic enabling and disabling of entire hardware
41 * blocks at runtime. This is especially important on the display side where
42 * software is supposed to control many power gates manually on recent hardware,
43 * since on the GT side a lot of the power management is done by the hardware.
44 * But even there some manual control at the device level is required.
45 *
46 * Since i915 supports a diverse set of platforms with a unified codebase and
47 * hardware engineers just love to shuffle functionality around between power
48 * domains there's a sizeable amount of indirection required. This file provides
49 * generic functions to the driver for grabbing and releasing references for
50 * abstract power domains. It then maps those to the actual power wells
51 * present for a given platform.
52 */
53
54#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
55
56#include <linux/sort.h>
57
58#define STACKDEPTH 8
59
60static noinline depot_stack_handle_t __save_depot_stack(void)
61{
62 unsigned long entries[STACKDEPTH];
63 unsigned int n;
64
65 n = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
66 return stack_depot_save(entries, n, GFP_NOWAIT | __GFP_NOWARN);
67}
68
69static void __print_depot_stack(depot_stack_handle_t stack,
70 char *buf, int sz, int indent)
71{
72 unsigned long *entries;
73 unsigned int nr_entries;
74
75 nr_entries = stack_depot_fetch(stack, &entries);
76 stack_trace_snprint(buf, sz, entries, nr_entries, indent);
77}
78
79static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
80{
81 spin_lock_init(&rpm->debug.lock);
82}
83
84static noinline depot_stack_handle_t
85track_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
86{
87 depot_stack_handle_t stack, *stacks;
88 unsigned long flags;
89
90 if (!rpm->available)
91 return -1;
92
93 stack = __save_depot_stack();
94 if (!stack)
95 return -1;
96
97 spin_lock_irqsave(&rpm->debug.lock, flags);
98
99 if (!rpm->debug.count)
100 rpm->debug.last_acquire = stack;
101
102 stacks = krealloc(rpm->debug.owners,
103 (rpm->debug.count + 1) * sizeof(*stacks),
104 GFP_NOWAIT | __GFP_NOWARN);
105 if (stacks) {
106 stacks[rpm->debug.count++] = stack;
107 rpm->debug.owners = stacks;
108 } else {
109 stack = -1;
110 }
111
112 spin_unlock_irqrestore(&rpm->debug.lock, flags);
113
114 return stack;
115}
116
117static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
118 depot_stack_handle_t stack)
119{
120 unsigned long flags, n;
121 bool found = false;
122
123 if (unlikely(stack == -1))
124 return;
125
126 spin_lock_irqsave(&rpm->debug.lock, flags);
127 for (n = rpm->debug.count; n--; ) {
128 if (rpm->debug.owners[n] == stack) {
129 memmove(rpm->debug.owners + n,
130 rpm->debug.owners + n + 1,
131 (--rpm->debug.count - n) * sizeof(stack));
132 found = true;
133 break;
134 }
135 }
136 spin_unlock_irqrestore(&rpm->debug.lock, flags);
137
138 if (WARN(!found,
139 "Unmatched wakeref (tracking %lu), count %u\n",
140 rpm->debug.count, atomic_read(&rpm->wakeref_count))) {
141 char *buf;
142
143 buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN);
144 if (!buf)
145 return;
146
147 __print_depot_stack(stack, buf, PAGE_SIZE, 2);
148 DRM_DEBUG_DRIVER("wakeref %x from\n%s", stack, buf);
149
150 stack = READ_ONCE(rpm->debug.last_release);
151 if (stack) {
152 __print_depot_stack(stack, buf, PAGE_SIZE, 2);
153 DRM_DEBUG_DRIVER("wakeref last released at\n%s", buf);
154 }
155
156 kfree(buf);
157 }
158}
159
160static int cmphandle(const void *_a, const void *_b)
161{
162 const depot_stack_handle_t * const a = _a, * const b = _b;
163
164 if (*a < *b)
165 return -1;
166 else if (*a > *b)
167 return 1;
168 else
169 return 0;
170}
171
172static void
173__print_intel_runtime_pm_wakeref(struct drm_printer *p,
174 const struct intel_runtime_pm_debug *dbg)
175{
176 unsigned long i;
177 char *buf;
178
179 buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN);
180 if (!buf)
181 return;
182
183 if (dbg->last_acquire) {
184 __print_depot_stack(dbg->last_acquire, buf, PAGE_SIZE, 2);
185 drm_printf(p, "Wakeref last acquired:\n%s", buf);
186 }
187
188 if (dbg->last_release) {
189 __print_depot_stack(dbg->last_release, buf, PAGE_SIZE, 2);
190 drm_printf(p, "Wakeref last released:\n%s", buf);
191 }
192
193 drm_printf(p, "Wakeref count: %lu\n", dbg->count);
194
195 sort(dbg->owners, dbg->count, sizeof(*dbg->owners), cmphandle, NULL);
196
197 for (i = 0; i < dbg->count; i++) {
198 depot_stack_handle_t stack = dbg->owners[i];
199 unsigned long rep;
200
201 rep = 1;
202 while (i + 1 < dbg->count && dbg->owners[i + 1] == stack)
203 rep++, i++;
204 __print_depot_stack(stack, buf, PAGE_SIZE, 2);
205 drm_printf(p, "Wakeref x%lu taken at:\n%s", rep, buf);
206 }
207
208 kfree(buf);
209}
210
211static noinline void
212__untrack_all_wakerefs(struct intel_runtime_pm_debug *debug,
213 struct intel_runtime_pm_debug *saved)
214{
215 *saved = *debug;
216
217 debug->owners = NULL;
218 debug->count = 0;
219 debug->last_release = __save_depot_stack();
220}
221
222static void
223dump_and_free_wakeref_tracking(struct intel_runtime_pm_debug *debug)
224{
225 if (debug->count) {
226 struct drm_printer p = drm_debug_printer("i915");
227
228 __print_intel_runtime_pm_wakeref(&p, debug);
229 }
230
231 kfree(debug->owners);
232}
233
234static noinline void
235__intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm)
236{
237 struct intel_runtime_pm_debug dbg = {};
238 unsigned long flags;
239
240 if (!atomic_dec_and_lock_irqsave(&rpm->wakeref_count,
241 &rpm->debug.lock,
242 flags))
243 return;
244
245 __untrack_all_wakerefs(&rpm->debug, &dbg);
246 spin_unlock_irqrestore(&rpm->debug.lock, flags);
247
248 dump_and_free_wakeref_tracking(&dbg);
249}
250
251static noinline void
252untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm)
253{
254 struct intel_runtime_pm_debug dbg = {};
255 unsigned long flags;
256
257 spin_lock_irqsave(&rpm->debug.lock, flags);
258 __untrack_all_wakerefs(&rpm->debug, &dbg);
259 spin_unlock_irqrestore(&rpm->debug.lock, flags);
260
261 dump_and_free_wakeref_tracking(&dbg);
262}
263
264void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
265 struct drm_printer *p)
266{
267 struct intel_runtime_pm_debug dbg = {};
268
269 do {
270 unsigned long alloc = dbg.count;
271 depot_stack_handle_t *s;
272
273 spin_lock_irq(&rpm->debug.lock);
274 dbg.count = rpm->debug.count;
275 if (dbg.count <= alloc) {
276 memcpy(dbg.owners,
277 rpm->debug.owners,
278 dbg.count * sizeof(*s));
279 }
280 dbg.last_acquire = rpm->debug.last_acquire;
281 dbg.last_release = rpm->debug.last_release;
282 spin_unlock_irq(&rpm->debug.lock);
283 if (dbg.count <= alloc)
284 break;
285
286 s = krealloc(dbg.owners,
287 dbg.count * sizeof(*s),
288 GFP_NOWAIT | __GFP_NOWARN);
289 if (!s)
290 goto out;
291
292 dbg.owners = s;
293 } while (1);
294
295 __print_intel_runtime_pm_wakeref(p, &dbg);
296
297out:
298 kfree(dbg.owners);
299}
300
301#else
302
303static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
304{
305}
306
307static depot_stack_handle_t
308track_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
309{
310 return -1;
311}
312
313static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
314 intel_wakeref_t wref)
315{
316}
317
318static void
319__intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm)
320{
321 atomic_dec(&rpm->wakeref_count);
322}
323
324static void
325untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm)
326{
327}
328
329#endif
330
331static void
332intel_runtime_pm_acquire(struct intel_runtime_pm *rpm, bool wakelock)
333{
334 if (wakelock) {
335 atomic_add(1 + INTEL_RPM_WAKELOCK_BIAS, &rpm->wakeref_count);
336 assert_rpm_wakelock_held(rpm);
337 } else {
338 atomic_inc(&rpm->wakeref_count);
339 assert_rpm_raw_wakeref_held(rpm);
340 }
341}
342
343static void
344intel_runtime_pm_release(struct intel_runtime_pm *rpm, int wakelock)
345{
346 if (wakelock) {
347 assert_rpm_wakelock_held(rpm);
348 atomic_sub(INTEL_RPM_WAKELOCK_BIAS, &rpm->wakeref_count);
349 } else {
350 assert_rpm_raw_wakeref_held(rpm);
351 }
352
353 __intel_wakeref_dec_and_check_tracking(rpm);
354}
355
356static intel_wakeref_t __intel_runtime_pm_get(struct intel_runtime_pm *rpm,
357 bool wakelock)
358{
359 int ret;
360
361 ret = pm_runtime_get_sync(rpm->kdev);
362 WARN_ONCE(ret < 0, "pm_runtime_get_sync() failed: %d\n", ret);
363
364 intel_runtime_pm_acquire(rpm, wakelock);
365
366 return track_intel_runtime_pm_wakeref(rpm);
367}
368
369/**
370 * intel_runtime_pm_get_raw - grab a raw runtime pm reference
371 * @rpm: the intel_runtime_pm structure
372 *
373 * This is the unlocked version of intel_display_power_is_enabled() and should
374 * only be used from error capture and recovery code where deadlocks are
375 * possible.
376 * This function grabs a device-level runtime pm reference (mostly used for
377 * asynchronous PM management from display code) and ensures that it is powered
378 * up. Raw references are not considered during wakelock assert checks.
379 *
380 * Any runtime pm reference obtained by this function must have a symmetric
381 * call to intel_runtime_pm_put_raw() to release the reference again.
382 *
383 * Returns: the wakeref cookie to pass to intel_runtime_pm_put_raw(), evaluates
384 * as True if the wakeref was acquired, or False otherwise.
385 */
386intel_wakeref_t intel_runtime_pm_get_raw(struct intel_runtime_pm *rpm)
387{
388 return __intel_runtime_pm_get(rpm, false);
389}
390
391/**
392 * intel_runtime_pm_get - grab a runtime pm reference
393 * @rpm: the intel_runtime_pm structure
394 *
395 * This function grabs a device-level runtime pm reference (mostly used for GEM
396 * code to ensure the GTT or GT is on) and ensures that it is powered up.
397 *
398 * Any runtime pm reference obtained by this function must have a symmetric
399 * call to intel_runtime_pm_put() to release the reference again.
400 *
401 * Returns: the wakeref cookie to pass to intel_runtime_pm_put()
402 */
403intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm)
404{
405 return __intel_runtime_pm_get(rpm, true);
406}
407
408/**
409 * intel_runtime_pm_get_if_in_use - grab a runtime pm reference if device in use
410 * @rpm: the intel_runtime_pm structure
411 *
412 * This function grabs a device-level runtime pm reference if the device is
413 * already in use and ensures that it is powered up. It is illegal to try
414 * and access the HW should intel_runtime_pm_get_if_in_use() report failure.
415 *
416 * Any runtime pm reference obtained by this function must have a symmetric
417 * call to intel_runtime_pm_put() to release the reference again.
418 *
419 * Returns: the wakeref cookie to pass to intel_runtime_pm_put(), evaluates
420 * as True if the wakeref was acquired, or False otherwise.
421 */
422intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm)
423{
424 if (IS_ENABLED(CONFIG_PM)) {
425 /*
426 * In cases runtime PM is disabled by the RPM core and we get
427 * an -EINVAL return value we are not supposed to call this
428 * function, since the power state is undefined. This applies
429 * atm to the late/early system suspend/resume handlers.
430 */
431 if (pm_runtime_get_if_in_use(rpm->kdev) <= 0)
432 return 0;
433 }
434
435 intel_runtime_pm_acquire(rpm, true);
436
437 return track_intel_runtime_pm_wakeref(rpm);
438}
439
440/**
441 * intel_runtime_pm_get_noresume - grab a runtime pm reference
442 * @rpm: the intel_runtime_pm structure
443 *
444 * This function grabs a device-level runtime pm reference (mostly used for GEM
445 * code to ensure the GTT or GT is on).
446 *
447 * It will _not_ power up the device but instead only check that it's powered
448 * on. Therefore it is only valid to call this functions from contexts where
449 * the device is known to be powered up and where trying to power it up would
450 * result in hilarity and deadlocks. That pretty much means only the system
451 * suspend/resume code where this is used to grab runtime pm references for
452 * delayed setup down in work items.
453 *
454 * Any runtime pm reference obtained by this function must have a symmetric
455 * call to intel_runtime_pm_put() to release the reference again.
456 *
457 * Returns: the wakeref cookie to pass to intel_runtime_pm_put()
458 */
459intel_wakeref_t intel_runtime_pm_get_noresume(struct intel_runtime_pm *rpm)
460{
461 assert_rpm_wakelock_held(rpm);
462 pm_runtime_get_noresume(rpm->kdev);
463
464 intel_runtime_pm_acquire(rpm, true);
465
466 return track_intel_runtime_pm_wakeref(rpm);
467}
468
469static void __intel_runtime_pm_put(struct intel_runtime_pm *rpm,
470 intel_wakeref_t wref,
471 bool wakelock)
472{
473 struct device *kdev = rpm->kdev;
474
475 untrack_intel_runtime_pm_wakeref(rpm, wref);
476
477 intel_runtime_pm_release(rpm, wakelock);
478
479 pm_runtime_mark_last_busy(kdev);
480 pm_runtime_put_autosuspend(kdev);
481}
482
483/**
484 * intel_runtime_pm_put_raw - release a raw runtime pm reference
485 * @rpm: the intel_runtime_pm structure
486 * @wref: wakeref acquired for the reference that is being released
487 *
488 * This function drops the device-level runtime pm reference obtained by
489 * intel_runtime_pm_get_raw() and might power down the corresponding
490 * hardware block right away if this is the last reference.
491 */
492void
493intel_runtime_pm_put_raw(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
494{
495 __intel_runtime_pm_put(rpm, wref, false);
496}
497
498/**
499 * intel_runtime_pm_put_unchecked - release an unchecked runtime pm reference
500 * @rpm: the intel_runtime_pm structure
501 *
502 * This function drops the device-level runtime pm reference obtained by
503 * intel_runtime_pm_get() and might power down the corresponding
504 * hardware block right away if this is the last reference.
505 *
506 * This function exists only for historical reasons and should be avoided in
507 * new code, as the correctness of its use cannot be checked. Always use
508 * intel_runtime_pm_put() instead.
509 */
510void intel_runtime_pm_put_unchecked(struct intel_runtime_pm *rpm)
511{
512 __intel_runtime_pm_put(rpm, -1, true);
513}
514
515#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_RUNTIME_PM)
516/**
517 * intel_runtime_pm_put - release a runtime pm reference
518 * @rpm: the intel_runtime_pm structure
519 * @wref: wakeref acquired for the reference that is being released
520 *
521 * This function drops the device-level runtime pm reference obtained by
522 * intel_runtime_pm_get() and might power down the corresponding
523 * hardware block right away if this is the last reference.
524 */
525void intel_runtime_pm_put(struct intel_runtime_pm *rpm, intel_wakeref_t wref)
526{
527 __intel_runtime_pm_put(rpm, wref, true);
528}
529#endif
530
531/**
532 * intel_runtime_pm_enable - enable runtime pm
533 * @rpm: the intel_runtime_pm structure
534 *
535 * This function enables runtime pm at the end of the driver load sequence.
536 *
537 * Note that this function does currently not enable runtime pm for the
538 * subordinate display power domains. That is done by
539 * intel_power_domains_enable().
540 */
541void intel_runtime_pm_enable(struct intel_runtime_pm *rpm)
542{
543 struct device *kdev = rpm->kdev;
544
545 /*
546 * Disable the system suspend direct complete optimization, which can
547 * leave the device suspended skipping the driver's suspend handlers
548 * if the device was already runtime suspended. This is needed due to
549 * the difference in our runtime and system suspend sequence and
550 * becaue the HDA driver may require us to enable the audio power
551 * domain during system suspend.
552 */
553 dev_pm_set_driver_flags(kdev, DPM_FLAG_NEVER_SKIP);
554
555 pm_runtime_set_autosuspend_delay(kdev, 10000); /* 10s */
556 pm_runtime_mark_last_busy(kdev);
557
558 /*
559 * Take a permanent reference to disable the RPM functionality and drop
560 * it only when unloading the driver. Use the low level get/put helpers,
561 * so the driver's own RPM reference tracking asserts also work on
562 * platforms without RPM support.
563 */
564 if (!rpm->available) {
565 int ret;
566
567 pm_runtime_dont_use_autosuspend(kdev);
568 ret = pm_runtime_get_sync(kdev);
569 WARN(ret < 0, "pm_runtime_get_sync() failed: %d\n", ret);
570 } else {
571 pm_runtime_use_autosuspend(kdev);
572 }
573
574 /*
575 * The core calls the driver load handler with an RPM reference held.
576 * We drop that here and will reacquire it during unloading in
577 * intel_power_domains_fini().
578 */
579 pm_runtime_put_autosuspend(kdev);
580}
581
582void intel_runtime_pm_disable(struct intel_runtime_pm *rpm)
583{
584 struct device *kdev = rpm->kdev;
585
586 /* Transfer rpm ownership back to core */
587 WARN(pm_runtime_get_sync(kdev) < 0,
588 "Failed to pass rpm ownership back to core\n");
589
590 pm_runtime_dont_use_autosuspend(kdev);
591
592 if (!rpm->available)
593 pm_runtime_put(kdev);
594}
595
596void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm)
597{
598 int count = atomic_read(&rpm->wakeref_count);
599
600 WARN(count,
601 "i915 raw-wakerefs=%d wakelocks=%d on cleanup\n",
602 intel_rpm_raw_wakeref_count(count),
603 intel_rpm_wakelock_count(count));
604
605 untrack_all_intel_runtime_pm_wakerefs(rpm);
606}
607
608void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm)
609{
610 struct drm_i915_private *i915 =
611 container_of(rpm, struct drm_i915_private, runtime_pm);
612 struct pci_dev *pdev = i915->drm.pdev;
613 struct device *kdev = &pdev->dev;
614
615 rpm->kdev = kdev;
616 rpm->available = HAS_RUNTIME_PM(i915);
617
618 init_intel_runtime_pm_wakeref(rpm);
619}