/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2019 Intel Corporation
*/
#ifndef INTEL_WAKEREF_H
#define INTEL_WAKEREF_H
#include <drm/drm_print.h>
#include <linux/atomic.h>
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/lockdep.h>
#include <linux/mutex.h>
#include <linux/refcount.h>
#include <linux/ref_tracker.h>
#include <linux/slab.h>
#include <linux/stackdepot.h>
#include <linux/timer.h>
#include <linux/workqueue.h>
typedef unsigned long intel_wakeref_t;
#define INTEL_REFTRACK_DEAD_COUNT 16
#define INTEL_REFTRACK_PRINT_LIMIT 16
#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;
struct intel_wakeref_ops {
int (*get)(struct intel_wakeref *wf);
int (*put)(struct intel_wakeref *wf);
};
struct intel_wakeref {
atomic_t count;
struct mutex mutex;
intel_wakeref_t wakeref;
struct drm_i915_private *i915;
const struct intel_wakeref_ops *ops;
struct delayed_work work;
#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF)
struct ref_tracker_dir debug;
#endif
};
struct intel_wakeref_lockclass {
struct lock_class_key mutex;
struct lock_class_key work;
};
void __intel_wakeref_init(struct intel_wakeref *wf,
struct drm_i915_private *i915,
const struct intel_wakeref_ops *ops,
struct intel_wakeref_lockclass *key,
const char *name);
#define intel_wakeref_init(wf, i915, ops, name) do { \
static struct intel_wakeref_lockclass __key; \
\
__intel_wakeref_init((wf), (i915), (ops), &__key, name); \
} while (0)
int __intel_wakeref_get_first(struct intel_wakeref *wf);
void __intel_wakeref_put_last(struct intel_wakeref *wf, unsigned long flags);
/**
* intel_wakeref_get: Acquire the wakeref
* @wf: the wakeref
*
* Acquire a hold on the wakeref. The first user to do so, will acquire
* the runtime pm wakeref and then call the intel_wakeref_ops->get()
* underneath the wakeref mutex.
*
* Note that intel_wakeref_ops->get() 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)
{
might_sleep();
if (unlikely(!atomic_inc_not_zero(&wf->count)))
return __intel_wakeref_get_first(wf);
return 0;
}
/**
* __intel_wakeref_get: Acquire the wakeref, again
* @wf: the wakeref
*
* Increment the wakeref counter, only valid if it is already held by
* the caller.
*
* See intel_wakeref_get().
*/
static inline void
__intel_wakeref_get(struct intel_wakeref *wf)
{
INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0);
atomic_inc(&wf->count);
}
/**
* intel_wakeref_get_if_active: 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);
}
enum {
INTEL_WAKEREF_PUT_ASYNC_BIT = 0,
__INTEL_WAKEREF_PUT_LAST_BIT__
};
static inline void
intel_wakeref_might_get(struct intel_wakeref *wf)
{
might_lock(&wf->mutex);
}
/**
* __intel_wakeref_put: Release the wakeref
* @wf: the wakeref
* @flags: control flags
*
* Release our hold on the wakeref. When there are no more users,
* the runtime pm wakeref will be released after the intel_wakeref_ops->put()
* callback is called underneath the wakeref mutex.
*
* Note that intel_wakeref_ops->put() is allowed to fail, in which case the
* runtime-pm wakeref is retained.
*
*/
static inline void
__intel_wakeref_put(struct intel_wakeref *wf, unsigned long flags)
#define INTEL_WAKEREF_PUT_ASYNC BIT(INTEL_WAKEREF_PUT_ASYNC_BIT)
#define INTEL_WAKEREF_PUT_DELAY \
GENMASK(BITS_PER_LONG - 1, __INTEL_WAKEREF_PUT_LAST_BIT__)
{
INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0);
if (unlikely(!atomic_add_unless(&wf->count, -1, 1)))
__intel_wakeref_put_last(wf, flags);
}
static inline void
intel_wakeref_put(struct intel_wakeref *wf)
{
might_sleep();
__intel_wakeref_put(wf, 0);
}
static inline void
intel_wakeref_put_async(struct intel_wakeref *wf)
{
__intel_wakeref_put(wf, INTEL_WAKEREF_PUT_ASYNC);
}
static inline void
intel_wakeref_put_delay(struct intel_wakeref *wf, unsigned long delay)
{
__intel_wakeref_put(wf,
INTEL_WAKEREF_PUT_ASYNC |
FIELD_PREP(INTEL_WAKEREF_PUT_DELAY, delay));
}
static inline void
intel_wakeref_might_put(struct intel_wakeref *wf)
{
might_lock(&wf->mutex);
}
/**
* 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_unlock_wait: Wait until the active callback is complete
* @wf: the wakeref
*
* Waits for the active callback (under the @wf->mutex or another CPU) is
* complete.
*/
static inline void
intel_wakeref_unlock_wait(struct intel_wakeref *wf)
{
mutex_lock(&wf->mutex);
mutex_unlock(&wf->mutex);
flush_delayed_work(&wf->work);
}
/**
* 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)
{
lockdep_assert_held(&wf->mutex);
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);
#define INTEL_WAKEREF_DEF ((intel_wakeref_t)(-1))
static inline intel_wakeref_t intel_ref_tracker_alloc(struct ref_tracker_dir *dir)
{
struct ref_tracker *user = NULL;
ref_tracker_alloc(dir, &user, GFP_NOWAIT);
return (intel_wakeref_t)user ?: INTEL_WAKEREF_DEF;
}
static inline void intel_ref_tracker_free(struct ref_tracker_dir *dir,
intel_wakeref_t handle)
{
struct ref_tracker *user;
user = (handle == INTEL_WAKEREF_DEF) ? NULL : (void *)handle;
ref_tracker_free(dir, &user);
}
void intel_ref_tracker_show(struct ref_tracker_dir *dir,
struct drm_printer *p);
#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF)
static inline intel_wakeref_t intel_wakeref_track(struct intel_wakeref *wf)
{
return intel_ref_tracker_alloc(&wf->debug);
}
static inline void intel_wakeref_untrack(struct intel_wakeref *wf,
intel_wakeref_t handle)
{
intel_ref_tracker_free(&wf->debug, handle);
}
#else
static inline intel_wakeref_t intel_wakeref_track(struct intel_wakeref *wf)
{
return -1;
}
static inline void intel_wakeref_untrack(struct intel_wakeref *wf,
intel_wakeref_t handle)
{
}
#endif
struct intel_wakeref_auto {
struct drm_i915_private *i915;
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 drm_i915_private *i915);
void intel_wakeref_auto_fini(struct intel_wakeref_auto *wf);
#endif /* INTEL_WAKEREF_H */
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