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/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2019 Intel Corporation
*/
#include "intel_runtime_pm.h"
#include "i915_gem.h"
static void rpm_get(struct intel_runtime_pm *rpm, struct intel_wakeref *wf)
{
wf->wakeref = intel_runtime_pm_get(rpm);
}
static void rpm_put(struct intel_runtime_pm *rpm, struct intel_wakeref *wf)
{
intel_wakeref_t wakeref = fetch_and_zero(&wf->wakeref);
intel_runtime_pm_put(rpm, wakeref);
GEM_BUG_ON(!wakeref);
}
int __intel_wakeref_get_first(struct intel_runtime_pm *rpm,
struct intel_wakeref *wf,
int (*fn)(struct intel_wakeref *wf))
{
/*
* Treat get/put as different subclasses, as we may need to run
* the put callback from under the shrinker and do not want to
* cross-contanimate that callback with any extra work performed
* upon acquiring the wakeref.
*/
mutex_lock_nested(&wf->mutex, SINGLE_DEPTH_NESTING);
if (!atomic_read(&wf->count)) {
int err;
rpm_get(rpm, wf);
err = fn(wf);
if (unlikely(err)) {
rpm_put(rpm, wf);
mutex_unlock(&wf->mutex);
return err;
}
smp_mb__before_atomic(); /* release wf->count */
}
atomic_inc(&wf->count);
mutex_unlock(&wf->mutex);
return 0;
}
int __intel_wakeref_put_last(struct intel_runtime_pm *rpm,
struct intel_wakeref *wf,
int (*fn)(struct intel_wakeref *wf))
{
int err;
err = fn(wf);
if (likely(!err))
rpm_put(rpm, wf);
else
atomic_inc(&wf->count);
mutex_unlock(&wf->mutex);
return err;
}
void __intel_wakeref_init(struct intel_wakeref *wf, struct lock_class_key *key)
{
__mutex_init(&wf->mutex, "wakeref", key);
atomic_set(&wf->count, 0);
wf->wakeref = 0;
}
static void wakeref_auto_timeout(struct timer_list *t)
{
struct intel_wakeref_auto *wf = from_timer(wf, t, timer);
intel_wakeref_t wakeref;
unsigned long flags;
if (!refcount_dec_and_lock_irqsave(&wf->count, &wf->lock, &flags))
return;
wakeref = fetch_and_zero(&wf->wakeref);
spin_unlock_irqrestore(&wf->lock, flags);
intel_runtime_pm_put(wf->rpm, wakeref);
}
void intel_wakeref_auto_init(struct intel_wakeref_auto *wf,
struct intel_runtime_pm *rpm)
{
spin_lock_init(&wf->lock);
timer_setup(&wf->timer, wakeref_auto_timeout, 0);
refcount_set(&wf->count, 0);
wf->wakeref = 0;
wf->rpm = rpm;
}
void intel_wakeref_auto(struct intel_wakeref_auto *wf, unsigned long timeout)
{
unsigned long flags;
if (!timeout) {
if (del_timer_sync(&wf->timer))
wakeref_auto_timeout(&wf->timer);
return;
}
/* Our mission is that we only extend an already active wakeref */
assert_rpm_wakelock_held(wf->rpm);
if (!refcount_inc_not_zero(&wf->count)) {
spin_lock_irqsave(&wf->lock, flags);
if (!refcount_inc_not_zero(&wf->count)) {
GEM_BUG_ON(wf->wakeref);
wf->wakeref = intel_runtime_pm_get_if_in_use(wf->rpm);
refcount_set(&wf->count, 1);
}
spin_unlock_irqrestore(&wf->lock, flags);
}
/*
* If we extend a pending timer, we will only get a single timer
* callback and so need to cancel the local inc by running the
* elided callback to keep the wf->count balanced.
*/
if (mod_timer(&wf->timer, jiffies + timeout))
wakeref_auto_timeout(&wf->timer);
}
void intel_wakeref_auto_fini(struct intel_wakeref_auto *wf)
{
intel_wakeref_auto(wf, 0);
GEM_BUG_ON(wf->wakeref);
}
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