mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-23 21:16:02 +07:00
ee33baa831
Previously, we assumed we could use mutex_trylock() within an atomic context, falling back to a worker if contended. However, such trickery is illegal inside interrupt context, and so we need to always use a worker under such circumstances. As we normally are in process context, we can typically use a plain mutex, and only defer to a work when we know we are being called from an interrupt path. Fixes:51fbd8de87
("drm/i915/pmu: Atomically acquire the gt_pm wakeref") References:a0855d24fc
("locking/mutex: Complain upon mutex API misuse in IRQ contexts") References: https://bugs.freedesktop.org/show_bug.cgi?id=111626 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20191120125433.3767149-1-chris@chris-wilson.co.uk (cherry picked from commit07779a76ee
) Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
247 lines
6.3 KiB
C
247 lines
6.3 KiB
C
/*
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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/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 work_struct 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 lock_class_key *key);
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#define intel_wakeref_init(wf, rpm, ops) do { \
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static struct lock_class_key __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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* @i915: the drm_i915_private device
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* @wf: the wakeref
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* @fn: callback for acquired the wakeref, called only on first acquire.
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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 @fn underneath the wakeref
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* mutex.
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*
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* Note that @fn is allowed to fail, in which case the runtime-pm wakeref
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* will be released and the acquisition unwound, 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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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_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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/**
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* intel_wakeref_put_flags: 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 @fn callback is called
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* underneath the wakeref mutex.
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*
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* Note that @fn is allowed to fail, in which case the runtime-pm wakeref
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* is retained and an error reported.
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*
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* Returns: 0 if the wakeref was released successfully, or a negative error
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* code otherwise.
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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(0)
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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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/**
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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_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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