diff options
Diffstat (limited to 'drivers/gpu/drm/i915/intel_wakeref.h')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_wakeref.h | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_wakeref.h b/drivers/gpu/drm/i915/intel_wakeref.h new file mode 100644 index 000000000000..9cbb2ebf575b --- /dev/null +++ b/drivers/gpu/drm/i915/intel_wakeref.h @@ -0,0 +1,164 @@ +/* + * SPDX-License-Identifier: MIT + * + * Copyright © 2019 Intel Corporation + */ + +#ifndef INTEL_WAKEREF_H +#define INTEL_WAKEREF_H + +#include <linux/atomic.h> +#include <linux/mutex.h> +#include <linux/refcount.h> +#include <linux/stackdepot.h> +#include <linux/timer.h> + +struct intel_runtime_pm; + +typedef depot_stack_handle_t intel_wakeref_t; + +struct intel_wakeref { + atomic_t count; + struct mutex mutex; + intel_wakeref_t wakeref; +}; + +void __intel_wakeref_init(struct intel_wakeref *wf, + struct lock_class_key *key); +#define intel_wakeref_init(wf) do { \ + static struct lock_class_key __key; \ + \ + __intel_wakeref_init((wf), &__key); \ +} while (0) + +int __intel_wakeref_get_first(struct intel_runtime_pm *rpm, + struct intel_wakeref *wf, + int (*fn)(struct intel_wakeref *wf)); +int __intel_wakeref_put_last(struct intel_runtime_pm *rpm, + struct intel_wakeref *wf, + int (*fn)(struct intel_wakeref *wf)); + +/** + * intel_wakeref_get: Acquire the wakeref + * @i915: the drm_i915_private device + * @wf: the wakeref + * @fn: callback for acquired the wakeref, called only on first acquire. + * + * Acquire a hold on the wakeref. The first user to do so, will acquire + * the runtime pm wakeref and then call the @fn underneath the wakeref + * mutex. + * + * Note that @fn 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_runtime_pm *rpm, + struct intel_wakeref *wf, + int (*fn)(struct intel_wakeref *wf)) +{ + if (unlikely(!atomic_inc_not_zero(&wf->count))) + return __intel_wakeref_get_first(rpm, wf, fn); + + return 0; +} + +/** + * intel_wakeref_put: Release the wakeref + * @i915: the drm_i915_private device + * @wf: the wakeref + * @fn: callback for releasing the wakeref, called only on final release. + * + * Release our hold on the wakeref. When there are no more users, + * the runtime pm wakeref will be released after the @fn callback is called + * underneath the wakeref mutex. + * + * Note that @fn is allowed to fail, in which case the runtime-pm wakeref + * is retained and an error reported. + * + * Returns: 0 if the wakeref was released successfully, or a negative error + * code otherwise. + */ +static inline int +intel_wakeref_put(struct intel_runtime_pm *rpm, + struct intel_wakeref *wf, + int (*fn)(struct intel_wakeref *wf)) +{ + if (atomic_dec_and_mutex_lock(&wf->count, &wf->mutex)) + return __intel_wakeref_put_last(rpm, wf, fn); + + return 0; +} + +/** + * 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_active: Query whether the wakeref is currently held + * @wf: the wakeref + * + * Returns: true if the wakeref is currently held. + */ +static inline bool +intel_wakeref_active(struct intel_wakeref *wf) +{ + return READ_ONCE(wf->wakeref); +} + +struct intel_wakeref_auto { + struct intel_runtime_pm *rpm; + 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 intel_runtime_pm *rpm); +void intel_wakeref_auto_fini(struct intel_wakeref_auto *wf); + +#endif /* INTEL_WAKEREF_H */ |