294 lines
7.2 KiB
C
294 lines
7.2 KiB
C
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/*
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* SPDX-License-Identifier: MIT
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*
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* Copyright © 2019 Intel Corporation
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*/
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#ifndef INTEL_WAKEREF_H
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#define INTEL_WAKEREF_H
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#include <linux/atomic.h>
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#include <linux/bitfield.h>
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#include <linux/bits.h>
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#include <linux/lockdep.h>
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#include <linux/mutex.h>
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#include <linux/refcount.h>
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#include <linux/stackdepot.h>
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#include <linux/timer.h>
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#include <linux/workqueue.h>
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#if IS_ENABLED(CONFIG_DRM_I915_DEBUG)
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#define INTEL_WAKEREF_BUG_ON(expr) BUG_ON(expr)
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#else
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#define INTEL_WAKEREF_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr)
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#endif
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struct intel_runtime_pm;
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struct intel_wakeref;
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typedef depot_stack_handle_t intel_wakeref_t;
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struct intel_wakeref_ops {
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int (*get)(struct intel_wakeref *wf);
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int (*put)(struct intel_wakeref *wf);
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};
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struct intel_wakeref {
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atomic_t count;
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struct mutex mutex;
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intel_wakeref_t wakeref;
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struct intel_runtime_pm *rpm;
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const struct intel_wakeref_ops *ops;
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struct delayed_work work;
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};
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struct intel_wakeref_lockclass {
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struct lock_class_key mutex;
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struct lock_class_key work;
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};
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void __intel_wakeref_init(struct intel_wakeref *wf,
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struct intel_runtime_pm *rpm,
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const struct intel_wakeref_ops *ops,
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struct intel_wakeref_lockclass *key);
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#define intel_wakeref_init(wf, rpm, ops) do { \
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static struct intel_wakeref_lockclass __key; \
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\
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__intel_wakeref_init((wf), (rpm), (ops), &__key); \
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} while (0)
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int __intel_wakeref_get_first(struct intel_wakeref *wf);
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void __intel_wakeref_put_last(struct intel_wakeref *wf, unsigned long flags);
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/**
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* intel_wakeref_get: Acquire the wakeref
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* @wf: the wakeref
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*
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* Acquire a hold on the wakeref. The first user to do so, will acquire
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* the runtime pm wakeref and then call the intel_wakeref_ops->get()
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* underneath the wakeref mutex.
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*
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* Note that intel_wakeref_ops->get() is allowed to fail, in which case
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* the runtime-pm wakeref will be released and the acquisition unwound,
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* and an error reported.
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*
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* Returns: 0 if the wakeref was acquired successfully, or a negative error
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* code otherwise.
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*/
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static inline int
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intel_wakeref_get(struct intel_wakeref *wf)
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{
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might_sleep();
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if (unlikely(!atomic_inc_not_zero(&wf->count)))
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return __intel_wakeref_get_first(wf);
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return 0;
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}
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/**
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* __intel_wakeref_get: Acquire the wakeref, again
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* @wf: the wakeref
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*
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* Increment the wakeref counter, only valid if it is already held by
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* the caller.
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*
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* See intel_wakeref_get().
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*/
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static inline void
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__intel_wakeref_get(struct intel_wakeref *wf)
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{
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INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0);
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atomic_inc(&wf->count);
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}
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/**
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* intel_wakeref_get_if_in_use: Acquire the wakeref
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* @wf: the wakeref
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*
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* Acquire a hold on the wakeref, but only if the wakeref is already
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* active.
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*
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* Returns: true if the wakeref was acquired, false otherwise.
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*/
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static inline bool
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intel_wakeref_get_if_active(struct intel_wakeref *wf)
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{
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return atomic_inc_not_zero(&wf->count);
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}
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enum {
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INTEL_WAKEREF_PUT_ASYNC_BIT = 0,
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__INTEL_WAKEREF_PUT_LAST_BIT__
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};
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static inline void
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intel_wakeref_might_get(struct intel_wakeref *wf)
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{
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might_lock(&wf->mutex);
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}
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/**
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* __intel_wakeref_put: Release the wakeref
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* @wf: the wakeref
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* @flags: control flags
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*
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* Release our hold on the wakeref. When there are no more users,
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* the runtime pm wakeref will be released after the intel_wakeref_ops->put()
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* callback is called underneath the wakeref mutex.
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*
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* Note that intel_wakeref_ops->put() is allowed to fail, in which case the
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* runtime-pm wakeref is retained.
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*
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*/
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static inline void
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__intel_wakeref_put(struct intel_wakeref *wf, unsigned long flags)
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#define INTEL_WAKEREF_PUT_ASYNC BIT(INTEL_WAKEREF_PUT_ASYNC_BIT)
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#define INTEL_WAKEREF_PUT_DELAY \
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GENMASK(BITS_PER_LONG - 1, __INTEL_WAKEREF_PUT_LAST_BIT__)
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{
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INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0);
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if (unlikely(!atomic_add_unless(&wf->count, -1, 1)))
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__intel_wakeref_put_last(wf, flags);
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}
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static inline void
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intel_wakeref_put(struct intel_wakeref *wf)
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{
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might_sleep();
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__intel_wakeref_put(wf, 0);
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}
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static inline void
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intel_wakeref_put_async(struct intel_wakeref *wf)
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{
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__intel_wakeref_put(wf, INTEL_WAKEREF_PUT_ASYNC);
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}
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static inline void
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intel_wakeref_put_delay(struct intel_wakeref *wf, unsigned long delay)
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{
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__intel_wakeref_put(wf,
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INTEL_WAKEREF_PUT_ASYNC |
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FIELD_PREP(INTEL_WAKEREF_PUT_DELAY, delay));
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}
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static inline void
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intel_wakeref_might_put(struct intel_wakeref *wf)
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{
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might_lock(&wf->mutex);
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}
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/**
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* intel_wakeref_lock: Lock the wakeref (mutex)
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* @wf: the wakeref
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*
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* Locks the wakeref to prevent it being acquired or released. New users
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* can still adjust the counter, but the wakeref itself (and callback)
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* cannot be acquired or released.
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*/
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static inline void
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intel_wakeref_lock(struct intel_wakeref *wf)
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__acquires(wf->mutex)
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{
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mutex_lock(&wf->mutex);
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}
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/**
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* intel_wakeref_unlock: Unlock the wakeref
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* @wf: the wakeref
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*
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* Releases a previously acquired intel_wakeref_lock().
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*/
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static inline void
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intel_wakeref_unlock(struct intel_wakeref *wf)
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__releases(wf->mutex)
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{
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mutex_unlock(&wf->mutex);
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}
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/**
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* intel_wakeref_unlock_wait: Wait until the active callback is complete
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* @wf: the wakeref
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*
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* Waits for the active callback (under the @wf->mutex or another CPU) is
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* complete.
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*/
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static inline void
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intel_wakeref_unlock_wait(struct intel_wakeref *wf)
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{
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mutex_lock(&wf->mutex);
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mutex_unlock(&wf->mutex);
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flush_delayed_work(&wf->work);
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}
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/**
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* intel_wakeref_is_active: Query whether the wakeref is currently held
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* @wf: the wakeref
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*
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* Returns: true if the wakeref is currently held.
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*/
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static inline bool
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intel_wakeref_is_active(const struct intel_wakeref *wf)
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{
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return READ_ONCE(wf->wakeref);
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}
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/**
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* __intel_wakeref_defer_park: Defer the current park callback
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* @wf: the wakeref
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*/
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static inline void
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__intel_wakeref_defer_park(struct intel_wakeref *wf)
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{
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lockdep_assert_held(&wf->mutex);
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INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count));
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atomic_set_release(&wf->count, 1);
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}
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/**
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* intel_wakeref_wait_for_idle: Wait until the wakeref is idle
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* @wf: the wakeref
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*
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* Wait for the earlier asynchronous release of the wakeref. Note
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* this will wait for any third party as well, so make sure you only wait
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* when you have control over the wakeref and trust no one else is acquiring
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* it.
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*
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* Return: 0 on success, error code if killed.
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*/
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int intel_wakeref_wait_for_idle(struct intel_wakeref *wf);
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struct intel_wakeref_auto {
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struct intel_runtime_pm *rpm;
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struct timer_list timer;
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intel_wakeref_t wakeref;
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spinlock_t lock;
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refcount_t count;
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};
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/**
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* intel_wakeref_auto: Delay the runtime-pm autosuspend
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* @wf: the wakeref
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* @timeout: relative timeout in jiffies
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*
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* The runtime-pm core uses a suspend delay after the last wakeref
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* is released before triggering runtime suspend of the device. That
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* delay is configurable via sysfs with little regard to the device
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* characteristics. Instead, we want to tune the autosuspend based on our
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* HW knowledge. intel_wakeref_auto() delays the sleep by the supplied
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* timeout.
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*
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* Pass @timeout = 0 to cancel a previous autosuspend by executing the
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* suspend immediately.
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*/
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void intel_wakeref_auto(struct intel_wakeref_auto *wf, unsigned long timeout);
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void intel_wakeref_auto_init(struct intel_wakeref_auto *wf,
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struct intel_runtime_pm *rpm);
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void intel_wakeref_auto_fini(struct intel_wakeref_auto *wf);
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#endif /* INTEL_WAKEREF_H */
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