Merge tag 'dma-fence-deadline' into HEAD

This series adds a deadline hint to fences, so realtime deadlines
such as vblank can be communicated to the fence signaller for power/
frequency management decisions.

This is partially inspired by a trick i915 does, but implemented
via dma-fence for a couple of reasons:

1) To continue to be able to use the atomic helpers
2) To support cases where display and gpu are different drivers

See https://patchwork.freedesktop.org/series/93035/

This does not yet add any UAPI, although this will be needed in
a number of cases:

1) Workloads "ping-ponging" between CPU and GPU, where we don't
   want the GPU freq governor to interpret time stalled waiting
   for GPU as "idle" time
2) Cases where the compositor is waiting for fences to be signaled
   before issuing the atomic ioctl, for example to maintain 60fps
   cursor updates even when the GPU is not able to maintain that
   framerate.

Signed-off-by: Rob Clark <robdclark@chromium.org>

5 files changed, 57 insertions, 22 deletions

diff --git a/include/drm/drm_vblank.h b/include/drm/drm_vblank.h
index 733a3e2d1d10..7f3957943dd1 100644
--- a/include/drm/drm_vblank.h
+++ b/include/drm/drm_vblank.h
@@ -230,6 +230,7 @@ bool drm_dev_has_vblank(const struct drm_device *dev);
 u64 drm_crtc_vblank_count(struct drm_crtc *crtc);
 u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
 				   ktime_t *vblanktime);
+int drm_crtc_next_vblank_start(struct drm_crtc *crtc, ktime_t *vblanktime);
 void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
 			       struct drm_pending_vblank_event *e);
 void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index 898608f87b96..c0ec6719282a 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -41,6 +41,15 @@
  */
 #define DRM_SCHED_FENCE_DONT_PIPELINE	DMA_FENCE_FLAG_USER_BITS
 
+/**
+ * DRM_SCHED_FENCE_FLAG_HAS_DEADLINE_BIT - A fence deadline hint has been set
+ *
+ * Because we could have a deadline hint can be set before the backing hw
+ * fence is created, we need to keep track of whether a deadline has already
+ * been set.
+ */
+#define DRM_SCHED_FENCE_FLAG_HAS_DEADLINE_BIT	(DMA_FENCE_FLAG_USER_BITS + 1)
+
 enum dma_resv_usage;
 struct dma_resv;
 struct drm_gem_object;
@@ -282,6 +291,12 @@ struct drm_sched_fence {
          */
 	struct dma_fence		finished;
 
+	/**
+	 * @deadline: deadline set on &drm_sched_fence.finished which
+	 * potentially needs to be propagated to &drm_sched_fence.parent
+	 */
+	ktime_t				deadline;
+
         /**
          * @parent: the fence returned by &drm_sched_backend_ops.run_job
          * when scheduling the job on hardware. We signal the
@@ -574,6 +589,8 @@ void drm_sched_entity_set_priority(struct drm_sched_entity *entity,
 				   enum drm_sched_priority priority);
 bool drm_sched_entity_is_ready(struct drm_sched_entity *entity);
 
+void drm_sched_fence_set_parent(struct drm_sched_fence *s_fence,
+				struct dma_fence *fence);
 struct drm_sched_fence *drm_sched_fence_alloc(
 	struct drm_sched_entity *s_entity, void *owner);
 void drm_sched_fence_init(struct drm_sched_fence *fence,
diff --git a/include/linux/dma-fence.h b/include/linux/dma-fence.h
index 775cdc0b4f24..d54b595a0fe0 100644
--- a/include/linux/dma-fence.h
+++ b/include/linux/dma-fence.h
@@ -257,6 +257,26 @@ struct dma_fence_ops {
 	 */
 	void (*timeline_value_str)(struct dma_fence *fence,
 				   char *str, int size);
+
+	/**
+	 * @set_deadline:
+	 *
+	 * Callback to allow a fence waiter to inform the fence signaler of
+	 * an upcoming deadline, such as vblank, by which point the waiter
+	 * would prefer the fence to be signaled by.  This is intended to
+	 * give feedback to the fence signaler to aid in power management
+	 * decisions, such as boosting GPU frequency.
+	 *
+	 * This is called without &dma_fence.lock held, it can be called
+	 * multiple times and from any context.  Locking is up to the callee
+	 * if it has some state to manage.  If multiple deadlines are set,
+	 * the expectation is to track the soonest one.  If the deadline is
+	 * before the current time, it should be interpreted as an immediate
+	 * deadline.
+	 *
+	 * This callback is optional.
+	 */
+	void (*set_deadline)(struct dma_fence *fence, ktime_t deadline);
 };
 
 void dma_fence_init(struct dma_fence *fence, const struct dma_fence_ops *ops,
@@ -583,6 +603,8 @@ static inline signed long dma_fence_wait(struct dma_fence *fence, bool intr)
 	return ret < 0 ? ret : 0;
 }
 
+void dma_fence_set_deadline(struct dma_fence *fence, ktime_t deadline);
+
 struct dma_fence *dma_fence_get_stub(void);
 struct dma_fence *dma_fence_allocate_private_stub(void);
 u64 dma_fence_context_alloc(unsigned num);
diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h
index 0637659a702c..8d0e34dad446 100644
--- a/include/linux/dma-resv.h
+++ b/include/linux/dma-resv.h
@@ -479,6 +479,8 @@ int dma_resv_get_singleton(struct dma_resv *obj, enum dma_resv_usage usage,
 int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src);
 long dma_resv_wait_timeout(struct dma_resv *obj, enum dma_resv_usage usage,
 			   bool intr, unsigned long timeout);
+void dma_resv_set_deadline(struct dma_resv *obj, enum dma_resv_usage usage,
+			   ktime_t deadline);
 bool dma_resv_test_signaled(struct dma_resv *obj, enum dma_resv_usage usage);
 void dma_resv_describe(struct dma_resv *obj, struct seq_file *seq);
 
diff --git a/include/uapi/linux/sync_file.h b/include/uapi/linux/sync_file.h
index ee2dcfb3d660..7e42a5b7558b 100644
--- a/include/uapi/linux/sync_file.h
+++ b/include/uapi/linux/sync_file.h
@@ -16,12 +16,16 @@
 #include <linux/types.h>
 
 /**
- * struct sync_merge_data - data passed to merge ioctl
+ * struct sync_merge_data - SYNC_IOC_MERGE: merge two fences
  * @name:	name of new fence
  * @fd2:	file descriptor of second fence
  * @fence:	returns the fd of the new fence to userspace
  * @flags:	merge_data flags
  * @pad:	padding for 64-bit alignment, should always be zero
+ *
+ * Creates a new fence containing copies of the sync_pts in both
+ * the calling fd and sync_merge_data.fd2.  Returns the new fence's
+ * fd in sync_merge_data.fence
  */
 struct sync_merge_data {
 	char	name[32];
@@ -34,8 +38,8 @@ struct sync_merge_data {
 /**
  * struct sync_fence_info - detailed fence information
  * @obj_name:		name of parent sync_timeline
-* @driver_name:	name of driver implementing the parent
-* @status:		status of the fence 0:active 1:signaled <0:error
+ * @driver_name:	name of driver implementing the parent
+ * @status:		status of the fence 0:active 1:signaled <0:error
  * @flags:		fence_info flags
  * @timestamp_ns:	timestamp of status change in nanoseconds
  */
@@ -48,14 +52,19 @@ struct sync_fence_info {
 };
 
 /**
- * struct sync_file_info - data returned from fence info ioctl
+ * struct sync_file_info - SYNC_IOC_FILE_INFO: get detailed information on a sync_file
  * @name:	name of fence
  * @status:	status of fence. 1: signaled 0:active <0:error
  * @flags:	sync_file_info flags
  * @num_fences	number of fences in the sync_file
  * @pad:	padding for 64-bit alignment, should always be zero
- * @sync_fence_info: pointer to array of structs sync_fence_info with all
+ * @sync_fence_info: pointer to array of struct &sync_fence_info with all
  *		 fences in the sync_file
+ *
+ * Takes a struct sync_file_info. If num_fences is 0, the field is updated
+ * with the actual number of fences. If num_fences is > 0, the system will
+ * use the pointer provided on sync_fence_info to return up to num_fences of
+ * struct sync_fence_info, with detailed fence information.
  */
 struct sync_file_info {
 	char	name[32];
@@ -69,30 +78,14 @@ struct sync_file_info {
 
 #define SYNC_IOC_MAGIC		'>'
 
-/**
+/*
  * Opcodes  0, 1 and 2 were burned during a API change to avoid users of the
  * old API to get weird errors when trying to handling sync_files. The API
  * change happened during the de-stage of the Sync Framework when there was
  * no upstream users available.
  */
 
-/**
- * DOC: SYNC_IOC_MERGE - merge two fences
- *
- * Takes a struct sync_merge_data.  Creates a new fence containing copies of
- * the sync_pts in both the calling fd and sync_merge_data.fd2.  Returns the
- * new fence's fd in sync_merge_data.fence
- */
 #define SYNC_IOC_MERGE		_IOWR(SYNC_IOC_MAGIC, 3, struct sync_merge_data)
-
-/**
- * DOC: SYNC_IOC_FILE_INFO - get detailed information on a sync_file
- *
- * Takes a struct sync_file_info. If num_fences is 0, the field is updated
- * with the actual number of fences. If num_fences is > 0, the system will
- * use the pointer provided on sync_fence_info to return up to num_fences of
- * struct sync_fence_info, with detailed fence information.
- */
 #define SYNC_IOC_FILE_INFO	_IOWR(SYNC_IOC_MAGIC, 4, struct sync_file_info)
 
 #endif /* _UAPI_LINUX_SYNC_H */