2 * SPDX-License-Identifier: MIT
4 * Copyright © 2019 Intel Corporation
7 #ifndef INTEL_WAKEREF_H
8 #define INTEL_WAKEREF_H
10 #include <linux/atomic.h>
11 #include <linux/mutex.h>
12 #include <linux/refcount.h>
13 #include <linux/stackdepot.h>
14 #include <linux/timer.h>
16 struct intel_runtime_pm;
18 typedef depot_stack_handle_t intel_wakeref_t;
20 struct intel_wakeref {
23 intel_wakeref_t wakeref;
26 void __intel_wakeref_init(struct intel_wakeref *wf,
27 struct lock_class_key *key);
28 #define intel_wakeref_init(wf) do { \
29 static struct lock_class_key __key; \
31 __intel_wakeref_init((wf), &__key); \
34 int __intel_wakeref_get_first(struct intel_runtime_pm *rpm,
35 struct intel_wakeref *wf,
36 int (*fn)(struct intel_wakeref *wf));
37 int __intel_wakeref_put_last(struct intel_runtime_pm *rpm,
38 struct intel_wakeref *wf,
39 int (*fn)(struct intel_wakeref *wf));
42 * intel_wakeref_get: Acquire the wakeref
43 * @i915: the drm_i915_private device
45 * @fn: callback for acquired the wakeref, called only on first acquire.
47 * Acquire a hold on the wakeref. The first user to do so, will acquire
48 * the runtime pm wakeref and then call the @fn underneath the wakeref
51 * Note that @fn is allowed to fail, in which case the runtime-pm wakeref
52 * will be released and the acquisition unwound, and an error reported.
54 * Returns: 0 if the wakeref was acquired successfully, or a negative error
58 intel_wakeref_get(struct intel_runtime_pm *rpm,
59 struct intel_wakeref *wf,
60 int (*fn)(struct intel_wakeref *wf))
62 if (unlikely(!atomic_inc_not_zero(&wf->count)))
63 return __intel_wakeref_get_first(rpm, wf, fn);
69 * intel_wakeref_put: Release the wakeref
70 * @i915: the drm_i915_private device
72 * @fn: callback for releasing the wakeref, called only on final release.
74 * Release our hold on the wakeref. When there are no more users,
75 * the runtime pm wakeref will be released after the @fn callback is called
76 * underneath the wakeref mutex.
78 * Note that @fn is allowed to fail, in which case the runtime-pm wakeref
79 * is retained and an error reported.
81 * Returns: 0 if the wakeref was released successfully, or a negative error
85 intel_wakeref_put(struct intel_runtime_pm *rpm,
86 struct intel_wakeref *wf,
87 int (*fn)(struct intel_wakeref *wf))
89 if (atomic_dec_and_mutex_lock(&wf->count, &wf->mutex))
90 return __intel_wakeref_put_last(rpm, wf, fn);
96 * intel_wakeref_lock: Lock the wakeref (mutex)
99 * Locks the wakeref to prevent it being acquired or released. New users
100 * can still adjust the counter, but the wakeref itself (and callback)
101 * cannot be acquired or released.
104 intel_wakeref_lock(struct intel_wakeref *wf)
105 __acquires(wf->mutex)
107 mutex_lock(&wf->mutex);
111 * intel_wakeref_unlock: Unlock the wakeref
114 * Releases a previously acquired intel_wakeref_lock().
117 intel_wakeref_unlock(struct intel_wakeref *wf)
118 __releases(wf->mutex)
120 mutex_unlock(&wf->mutex);
124 * intel_wakeref_active: Query whether the wakeref is currently held
127 * Returns: true if the wakeref is currently held.
130 intel_wakeref_active(struct intel_wakeref *wf)
132 return READ_ONCE(wf->wakeref);
135 struct intel_wakeref_auto {
136 struct intel_runtime_pm *rpm;
137 struct timer_list timer;
138 intel_wakeref_t wakeref;
144 * intel_wakeref_auto: Delay the runtime-pm autosuspend
146 * @timeout: relative timeout in jiffies
148 * The runtime-pm core uses a suspend delay after the last wakeref
149 * is released before triggering runtime suspend of the device. That
150 * delay is configurable via sysfs with little regard to the device
151 * characteristics. Instead, we want to tune the autosuspend based on our
152 * HW knowledge. intel_wakeref_auto() delays the sleep by the supplied
155 * Pass @timeout = 0 to cancel a previous autosuspend by executing the
156 * suspend immediately.
158 void intel_wakeref_auto(struct intel_wakeref_auto *wf, unsigned long timeout);
160 void intel_wakeref_auto_init(struct intel_wakeref_auto *wf,
161 struct intel_runtime_pm *rpm);
162 void intel_wakeref_auto_fini(struct intel_wakeref_auto *wf);
164 #endif /* INTEL_WAKEREF_H */