[PATCH v4 3/7] drm/xe: Add xe_exec_queue_last_fence_test_dep

[Matthew Brost <matthew.brost@intel.com>]

Helpful to determine if a bind can immediately use CPU or needs to be
deferred a drm scheduler job.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
---
 drivers/gpu/drm/xe/xe_exec_queue.c | 23 +++++++++++++++++++++++
 drivers/gpu/drm/xe/xe_exec_queue.h |  2 ++
 2 files changed, 25 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_exec_queue.c b/drivers/gpu/drm/xe/xe_exec_queue.c
index 0ba37835849b..65b4d1da6c93 100644
--- a/drivers/gpu/drm/xe/xe_exec_queue.c
+++ b/drivers/gpu/drm/xe/xe_exec_queue.c
@@ -906,3 +906,26 @@ void xe_exec_queue_last_fence_set(struct xe_exec_queue *q, struct xe_vm *vm,
 	xe_exec_queue_last_fence_put(q, vm);
 	q->last_fence = dma_fence_get(fence);
 }
+
+/**
+ * xe_exec_queue_last_fence_test_dep - Test last fence dependency of queue
+ * @q: The exec queue
+ * @vm: The VM the engine does a bind or exec for
+ *
+ * Returns:
+ * 0 on success on dependency, -ETIME on dependency
+ */
+int xe_exec_queue_last_fence_test_dep(struct xe_exec_queue *q, struct xe_vm *vm)
+{
+	struct dma_fence *fence;
+	int err = 0;
+
+	fence = xe_exec_queue_last_fence_get(q, vm);
+	if (fence) {
+		err = test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags) ?
+			0 : -ETIME;
+		dma_fence_put(fence);
+	}
+
+	return err;
+}
diff --git a/drivers/gpu/drm/xe/xe_exec_queue.h b/drivers/gpu/drm/xe/xe_exec_queue.h
index 289a3a51d2a2..ded77b0f3b90 100644
--- a/drivers/gpu/drm/xe/xe_exec_queue.h
+++ b/drivers/gpu/drm/xe/xe_exec_queue.h
@@ -75,6 +75,8 @@ struct dma_fence *xe_exec_queue_last_fence_get(struct xe_exec_queue *e,
 					       struct xe_vm *vm);
 void xe_exec_queue_last_fence_set(struct xe_exec_queue *e, struct xe_vm *vm,
 				  struct dma_fence *fence);
+int xe_exec_queue_last_fence_test_dep(struct xe_exec_queue *q,
+				      struct xe_vm *vm);
 void xe_exec_queue_update_run_ticks(struct xe_exec_queue *q);
 
 #endif
-- 
2.34.1