From d91e657876a96af4f00cc374e26a7a9e8c40d6de Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 24 Apr 2019 21:07:13 +0100 Subject: [PATCH] drm/i915: Introduce struct intel_wakeref For controlling runtime pm of the GT and engines, we would like to have a callback to do extra work the first time we wake up and the last time we drop the wakeref. This first/last access needs serialisation and so we encompass a mutex with the regular intel_wakeref_t tracker. v2: Drop the _once naming and report the errors. Signed-off-by: Chris Wilson Cc; Tvrtko Ursulin Reviewed-by: Tvrtko Ursulin Link: https://patchwork.freedesktop.org/patch/msgid/20190424200717.1686-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/Makefile | 1 + drivers/gpu/drm/i915/Makefile.header-test | 3 +- drivers/gpu/drm/i915/i915_drv.h | 3 +- drivers/gpu/drm/i915/intel_wakeref.c | 61 ++++++++++ drivers/gpu/drm/i915/intel_wakeref.h | 133 ++++++++++++++++++++++ 5 files changed, 198 insertions(+), 3 deletions(-) create mode 100644 drivers/gpu/drm/i915/intel_wakeref.c create mode 100644 drivers/gpu/drm/i915/intel_wakeref.h diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile index 40130cf5c003..233bad5e361f 100644 --- a/drivers/gpu/drm/i915/Makefile +++ b/drivers/gpu/drm/i915/Makefile @@ -50,6 +50,7 @@ i915-y += i915_drv.o \ intel_device_info.o \ intel_pm.o \ intel_runtime_pm.o \ + intel_wakeref.o \ intel_uncore.o # core library code diff --git a/drivers/gpu/drm/i915/Makefile.header-test b/drivers/gpu/drm/i915/Makefile.header-test index 96a5d90629ec..e6b3e7588860 100644 --- a/drivers/gpu/drm/i915/Makefile.header-test +++ b/drivers/gpu/drm/i915/Makefile.header-test @@ -31,7 +31,8 @@ header_test := \ intel_psr.h \ intel_sdvo.h \ intel_sprite.h \ - intel_tv.h + intel_tv.h \ + intel_wakeref.h quiet_cmd_header_test = HDRTEST $@ cmd_header_test = echo "\#include \"$( $@ diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index d37832ffb471..437e394d9fa6 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -74,6 +74,7 @@ #include "intel_opregion.h" #include "intel_uc.h" #include "intel_uncore.h" +#include "intel_wakeref.h" #include "intel_wopcm.h" #include "i915_gem.h" @@ -134,8 +135,6 @@ bool i915_error_injected(void); __i915_printk(i915, i915_error_injected() ? KERN_DEBUG : KERN_ERR, \ fmt, ##__VA_ARGS__) -typedef depot_stack_handle_t intel_wakeref_t; - enum hpd_pin { HPD_NONE = 0, HPD_TV = HPD_NONE, /* TV is known to be unreliable */ diff --git a/drivers/gpu/drm/i915/intel_wakeref.c b/drivers/gpu/drm/i915/intel_wakeref.c new file mode 100644 index 000000000000..1f94bc4ff9e4 --- /dev/null +++ b/drivers/gpu/drm/i915/intel_wakeref.c @@ -0,0 +1,61 @@ +/* + * SPDX-License-Identifier: MIT + * + * Copyright © 2019 Intel Corporation + */ + +#include "intel_drv.h" +#include "intel_wakeref.h" + +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; + + wf->wakeref = intel_runtime_pm_get(i915); + + err = fn(wf); + if (unlikely(err)) { + intel_runtime_pm_put(i915, wf->wakeref); + 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)) + intel_runtime_pm_put(i915, wf->wakeref); + 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); +} diff --git a/drivers/gpu/drm/i915/intel_wakeref.h b/drivers/gpu/drm/i915/intel_wakeref.h new file mode 100644 index 000000000000..a979d638344b --- /dev/null +++ b/drivers/gpu/drm/i915/intel_wakeref.h @@ -0,0 +1,133 @@ +/* + * SPDX-License-Identifier: MIT + * + * Copyright © 2019 Intel Corporation + */ + +#ifndef INTEL_WAKEREF_H +#define INTEL_WAKEREF_H + +#include +#include +#include + +struct drm_i915_private; + +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 drm_i915_private *i915, + struct intel_wakeref *wf, + int (*fn)(struct intel_wakeref *wf)); +int __intel_wakeref_put_last(struct drm_i915_private *i915, + 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 drm_i915_private *i915, + struct intel_wakeref *wf, + int (*fn)(struct intel_wakeref *wf)) +{ + if (unlikely(!atomic_inc_not_zero(&wf->count))) + return __intel_wakeref_get_first(i915, 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 drm_i915_private *i915, + 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(i915, 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 atomic_read(&wf->count); +} + +#endif /* INTEL_WAKEREF_H */ -- 2.30.2