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/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2019 Intel Corporation
*/
#include "intel_drv.h"
#include "intel_wakeref.h"
static void rpm_get(struct drm_i915_private *i915, struct intel_wakeref *wf)
{
wf->wakeref = intel_runtime_pm_get(i915);
}
static void rpm_put(struct drm_i915_private *i915, struct intel_wakeref *wf)
{
intel_wakeref_t wakeref = fetch_and_zero(&wf->wakeref);
intel_runtime_pm_put(i915, wakeref);
GEM_BUG_ON(!wakeref);
}
int __intel_wakeref_get_first(struct drm_i915_private *i915,
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(i915, wf);
err = fn(wf);
if (unlikely(err)) {
rpm_put(i915, 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 drm_i915_private *i915,
struct intel_wakeref *wf,
int (*fn)(struct intel_wakeref *wf))
{
int err;
err = fn(wf);
if (likely(!err))
rpm_put(i915, 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;
}
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