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d91e657876
For controlling runtime pm of the GT and engines, we would like to have a callback to do extra work the first time we wake up and the last time we drop the wakeref. This first/last access needs serialisation and so we encompass a mutex with the regular intel_wakeref_t tracker. v2: Drop the _once naming and report the errors. 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/20190424200717.1686-1-chris@chris-wilson.co.uk
133 lines
3.4 KiB
C
133 lines
3.4 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/mutex.h>
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#include <linux/stackdepot.h>
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struct drm_i915_private;
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typedef depot_stack_handle_t intel_wakeref_t;
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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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};
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void __intel_wakeref_init(struct intel_wakeref *wf,
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struct lock_class_key *key);
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#define intel_wakeref_init(wf) do { \
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static struct lock_class_key __key; \
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\
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__intel_wakeref_init((wf), &__key); \
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} while (0)
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int __intel_wakeref_get_first(struct drm_i915_private *i915,
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struct intel_wakeref *wf,
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int (*fn)(struct intel_wakeref *wf));
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int __intel_wakeref_put_last(struct drm_i915_private *i915,
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struct intel_wakeref *wf,
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int (*fn)(struct intel_wakeref *wf));
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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 drm_i915_private *i915,
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struct intel_wakeref *wf,
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int (*fn)(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(i915, wf, fn);
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return 0;
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}
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/**
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* intel_wakeref_put: Release 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 releasing the wakeref, called only on final release.
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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 int
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intel_wakeref_put(struct drm_i915_private *i915,
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struct intel_wakeref *wf,
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int (*fn)(struct intel_wakeref *wf))
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{
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if (atomic_dec_and_mutex_lock(&wf->count, &wf->mutex))
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return __intel_wakeref_put_last(i915, wf, fn);
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return 0;
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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_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_active(struct intel_wakeref *wf)
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{
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return atomic_read(&wf->count);
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}
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#endif /* INTEL_WAKEREF_H */
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