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/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2019 Intel Corporation
*/
#ifndef INTEL_WAKEREF_H
#define INTEL_WAKEREF_H
#include <linux/atomic.h>
#include <linux/bits.h>
#include <linux/mutex.h>
#include <linux/refcount.h>
#include <linux/stackdepot.h>
#include <linux/timer.h>
#include <linux/workqueue.h>
#if IS_ENABLED(CONFIG_DRM_I915_DEBUG)
#define INTEL_WAKEREF_BUG_ON(expr) BUG_ON(expr)
#else
#define INTEL_WAKEREF_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr)
#endif
struct intel_runtime_pm;
struct intel_wakeref;
typedef depot_stack_handle_t intel_wakeref_t;
struct intel_wakeref_ops {
int (*get)(struct intel_wakeref *wf);
int (*put)(struct intel_wakeref *wf);
unsigned long flags;
#define INTEL_WAKEREF_PUT_ASYNC BIT(0)
};
struct intel_wakeref {
atomic_t count;
struct mutex mutex;
intel_wakeref_t wakeref;
struct intel_runtime_pm *rpm;
const struct intel_wakeref_ops *ops;
struct work_struct work;
};
void __intel_wakeref_init(struct intel_wakeref *wf,
struct intel_runtime_pm *rpm,
const struct intel_wakeref_ops *ops,
struct lock_class_key *key);
#define intel_wakeref_init(wf, rpm, ops) do { \
static struct lock_class_key __key; \
\
__intel_wakeref_init((wf), (rpm), (ops), &__key); \
} while (0)
int __intel_wakeref_get_first(struct intel_wakeref *wf);
void __intel_wakeref_put_last(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_wakeref *wf)
{
if (unlikely(!atomic_inc_not_zero(&wf->count)))
return __intel_wakeref_get_first(wf);
return 0;
}
/**
* intel_wakeref_get_if_in_use: Acquire the wakeref
* @wf: the wakeref
*
* Acquire a hold on the wakeref, but only if the wakeref is already
* active.
*
* Returns: true if the wakeref was acquired, false otherwise.
*/
static inline bool
intel_wakeref_get_if_active(struct intel_wakeref *wf)
{
return atomic_inc_not_zero(&wf->count);
}
/**
* 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 void
intel_wakeref_put(struct intel_wakeref *wf)
{
INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0);
if (unlikely(!atomic_add_unless(&wf->count, -1, 1)))
__intel_wakeref_put_last(wf);
}
/**
* 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_is_active: Query whether the wakeref is currently held
* @wf: the wakeref
*
* Returns: true if the wakeref is currently held.
*/
static inline bool
intel_wakeref_is_active(const struct intel_wakeref *wf)
{
return READ_ONCE(wf->wakeref);
}
/**
* __intel_wakeref_defer_park: Defer the current park callback
* @wf: the wakeref
*/
static inline void
__intel_wakeref_defer_park(struct intel_wakeref *wf)
{
INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count));
atomic_set_release(&wf->count, 1);
}
/**
* intel_wakeref_wait_for_idle: Wait until the wakeref is idle
* @wf: the wakeref
*
* Wait for the earlier asynchronous release of the wakeref. Note
* this will wait for any third party as well, so make sure you only wait
* when you have control over the wakeref and trust no one else is acquiring
* it.
*
* Return: 0 on success, error code if killed.
*/
int intel_wakeref_wait_for_idle(struct intel_wakeref *wf);
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 */
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