summaryrefslogtreecommitdiffstats
path: root/drivers/gpu/drm/i915/intel_wakeref.h
blob: 68aa3be4825153fd1e6fb32afb0020c3825fe5c1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright © 2019 Intel Corporation
 */

#ifndef INTEL_WAKEREF_H
#define INTEL_WAKEREF_H

#include <drm/drm_print.h>

#include <linux/atomic.h>
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/lockdep.h>
#include <linux/mutex.h>
#include <linux/refcount.h>
#include <linux/ref_tracker.h>
#include <linux/slab.h>
#include <linux/stackdepot.h>
#include <linux/timer.h>
#include <linux/workqueue.h>

typedef unsigned long intel_wakeref_t;

#define INTEL_REFTRACK_DEAD_COUNT 16
#define INTEL_REFTRACK_PRINT_LIMIT 16

#if IS_ENABLED(CONFIG_DRM_I915_DEBUG)
#define INTEL_WAKEREF_BUG_ON(expr) BUG_ON(expr)
#else
#define INTEL_WAKEREF_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr)
#endif

struct intel_runtime_pm;
struct intel_wakeref;

struct intel_wakeref_ops {
	int (*get)(struct intel_wakeref *wf);
	int (*put)(struct intel_wakeref *wf);
};

struct intel_wakeref {
	atomic_t count;
	struct mutex mutex;

	intel_wakeref_t wakeref;

	struct drm_i915_private *i915;
	const struct intel_wakeref_ops *ops;

	struct delayed_work work;

#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF)
	struct ref_tracker_dir debug;
#endif
};

struct intel_wakeref_lockclass {
	struct lock_class_key mutex;
	struct lock_class_key work;
};

void __intel_wakeref_init(struct intel_wakeref *wf,
			  struct drm_i915_private *i915,
			  const struct intel_wakeref_ops *ops,
			  struct intel_wakeref_lockclass *key,
			  const char *name);
#define intel_wakeref_init(wf, i915, ops, name) do {			\
	static struct intel_wakeref_lockclass __key;			\
									\
	__intel_wakeref_init((wf), (i915), (ops), &__key, name);	\
} while (0)

int __intel_wakeref_get_first(struct intel_wakeref *wf);
void __intel_wakeref_put_last(struct intel_wakeref *wf, unsigned long flags);

/**
 * intel_wakeref_get: Acquire the wakeref
 * @wf: the wakeref
 *
 * Acquire a hold on the wakeref. The first user to do so, will acquire
 * the runtime pm wakeref and then call the intel_wakeref_ops->get()
 * underneath the wakeref mutex.
 *
 * Note that intel_wakeref_ops->get() is allowed to fail, in which case
 * the runtime-pm wakeref will be released and the acquisition unwound,
 * and an error reported.
 *
 * Returns: 0 if the wakeref was acquired successfully, or a negative error
 * code otherwise.
 */
static inline int
intel_wakeref_get(struct intel_wakeref *wf)
{
	might_sleep();
	if (unlikely(!atomic_inc_not_zero(&wf->count)))
		return __intel_wakeref_get_first(wf);

	return 0;
}

/**
 * __intel_wakeref_get: Acquire the wakeref, again
 * @wf: the wakeref
 *
 * Increment the wakeref counter, only valid if it is already held by
 * the caller.
 *
 * See intel_wakeref_get().
 */
static inline void
__intel_wakeref_get(struct intel_wakeref *wf)
{
	INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0);
	atomic_inc(&wf->count);
}

/**
 * intel_wakeref_get_if_active: Acquire the wakeref
 * @wf: the wakeref
 *
 * Acquire a hold on the wakeref, but only if the wakeref is already
 * active.
 *
 * Returns: true if the wakeref was acquired, false otherwise.
 */
static inline bool
intel_wakeref_get_if_active(struct intel_wakeref *wf)
{
	return atomic_inc_not_zero(&wf->count);
}

enum {
	INTEL_WAKEREF_PUT_ASYNC_BIT = 0,
	__INTEL_WAKEREF_PUT_LAST_BIT__
};

static inline void
intel_wakeref_might_get(struct intel_wakeref *wf)
{
	might_lock(&wf->mutex);
}

/**
 * __intel_wakeref_put: Release the wakeref
 * @wf: the wakeref
 * @flags: control flags
 *
 * Release our hold on the wakeref. When there are no more users,
 * the runtime pm wakeref will be released after the intel_wakeref_ops->put()
 * callback is called underneath the wakeref mutex.
 *
 * Note that intel_wakeref_ops->put() is allowed to fail, in which case the
 * runtime-pm wakeref is retained.
 *
 */
static inline void
__intel_wakeref_put(struct intel_wakeref *wf, unsigned long flags)
#define INTEL_WAKEREF_PUT_ASYNC BIT(INTEL_WAKEREF_PUT_ASYNC_BIT)
#define INTEL_WAKEREF_PUT_DELAY \
	GENMASK(BITS_PER_LONG - 1, __INTEL_WAKEREF_PUT_LAST_BIT__)
{
	INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0);
	if (unlikely(!atomic_add_unless(&wf->count, -1, 1)))
		__intel_wakeref_put_last(wf, flags);
}

static inline void
intel_wakeref_put(struct intel_wakeref *wf)
{
	might_sleep();
	__intel_wakeref_put(wf, 0);
}

static inline void
intel_wakeref_put_async(struct intel_wakeref *wf)
{
	__intel_wakeref_put(wf, INTEL_WAKEREF_PUT_ASYNC);
}

static inline void
intel_wakeref_put_delay(struct intel_wakeref *wf, unsigned long delay)
{
	__intel_wakeref_put(wf,
			    INTEL_WAKEREF_PUT_ASYNC |
			    FIELD_PREP(INTEL_WAKEREF_PUT_DELAY, delay));
}

static inline void
intel_wakeref_might_put(struct intel_wakeref *wf)
{
	might_lock(&wf->mutex);
}

/**
 * intel_wakeref_lock: Lock the wakeref (mutex)
 * @wf: the wakeref
 *
 * Locks the wakeref to prevent it being acquired or released. New users
 * can still adjust the counter, but the wakeref itself (and callback)
 * cannot be acquired or released.
 */
static inline void
intel_wakeref_lock(struct intel_wakeref *wf)
	__acquires(wf->mutex)
{
	mutex_lock(&wf->mutex);
}

/**
 * intel_wakeref_unlock: Unlock the wakeref
 * @wf: the wakeref
 *
 * Releases a previously acquired intel_wakeref_lock().
 */
static inline void
intel_wakeref_unlock(struct intel_wakeref *wf)
	__releases(wf->mutex)
{
	mutex_unlock(&wf->mutex);
}

/**
 * intel_wakeref_unlock_wait: Wait until the active callback is complete
 * @wf: the wakeref
 *
 * Waits for the active callback (under the @wf->mutex or another CPU) is
 * complete.
 */
static inline void
intel_wakeref_unlock_wait(struct intel_wakeref *wf)
{
	mutex_lock(&wf->mutex);
	mutex_unlock(&wf->mutex);
	flush_delayed_work(&wf->work);
}

/**
 * intel_wakeref_is_active: Query whether the wakeref is currently held
 * @wf: the wakeref
 *
 * Returns: true if the wakeref is currently held.
 */
static inline bool
intel_wakeref_is_active(const struct intel_wakeref *wf)
{
	return READ_ONCE(wf->wakeref);
}

/**
 * __intel_wakeref_defer_park: Defer the current park callback
 * @wf: the wakeref
 */
static inline void
__intel_wakeref_defer_park(struct intel_wakeref *wf)
{
	lockdep_assert_held(&wf->mutex);
	INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count));
	atomic_set_release(&wf->count, 1);
}

/**
 * intel_wakeref_wait_for_idle: Wait until the wakeref is idle
 * @wf: the wakeref
 *
 * Wait for the earlier asynchronous release of the wakeref. Note
 * this will wait for any third party as well, so make sure you only wait
 * when you have control over the wakeref and trust no one else is acquiring
 * it.
 *
 * Return: 0 on success, error code if killed.
 */
int intel_wakeref_wait_for_idle(struct intel_wakeref *wf);

#define INTEL_WAKEREF_DEF ((intel_wakeref_t)(-1))

static inline intel_wakeref_t intel_ref_tracker_alloc(struct ref_tracker_dir *dir)
{
	struct ref_tracker *user = NULL;

	ref_tracker_alloc(dir, &user, GFP_NOWAIT);

	return (intel_wakeref_t)user ?: INTEL_WAKEREF_DEF;
}

static inline void intel_ref_tracker_free(struct ref_tracker_dir *dir,
					  intel_wakeref_t handle)
{
	struct ref_tracker *user;

	user = (handle == INTEL_WAKEREF_DEF) ? NULL : (void *)handle;

	ref_tracker_free(dir, &user);
}

void intel_ref_tracker_show(struct ref_tracker_dir *dir,
			    struct drm_printer *p);

#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF)

static inline intel_wakeref_t intel_wakeref_track(struct intel_wakeref *wf)
{
	return intel_ref_tracker_alloc(&wf->debug);
}

static inline void intel_wakeref_untrack(struct intel_wakeref *wf,
					 intel_wakeref_t handle)
{
	intel_ref_tracker_free(&wf->debug, handle);
}

#else

static inline intel_wakeref_t intel_wakeref_track(struct intel_wakeref *wf)
{
	return -1;
}

static inline void intel_wakeref_untrack(struct intel_wakeref *wf,
					 intel_wakeref_t handle)
{
}

#endif

struct intel_wakeref_auto {
	struct drm_i915_private *i915;
	struct timer_list timer;
	intel_wakeref_t wakeref;
	spinlock_t lock;
	refcount_t count;
};

/**
 * intel_wakeref_auto: Delay the runtime-pm autosuspend
 * @wf: the wakeref
 * @timeout: relative timeout in jiffies
 *
 * The runtime-pm core uses a suspend delay after the last wakeref
 * is released before triggering runtime suspend of the device. That
 * delay is configurable via sysfs with little regard to the device
 * characteristics. Instead, we want to tune the autosuspend based on our
 * HW knowledge. intel_wakeref_auto() delays the sleep by the supplied
 * timeout.
 *
 * Pass @timeout = 0 to cancel a previous autosuspend by executing the
 * suspend immediately.
 */
void intel_wakeref_auto(struct intel_wakeref_auto *wf, unsigned long timeout);

void intel_wakeref_auto_init(struct intel_wakeref_auto *wf,
			     struct drm_i915_private *i915);
void intel_wakeref_auto_fini(struct intel_wakeref_auto *wf);

#endif /* INTEL_WAKEREF_H */