drm/msm: handle read vs write fences

The userspace API already had everything needed to handle read vs write
synchronization.  This patch actually bothers to hook it up properly, so
that we don't need to (for example) stall on userspace read access to a
buffer that gpu is also still reading.

Signed-off-by: Rob Clark <robdclark@gmail.com>

1 files changed, 18 insertions, 7 deletions

diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index 6b5a6c8c765..df0390f5ec5 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -393,11 +393,14 @@ int msm_gem_queue_inactive_work(struct drm_gem_object *obj,
 }
 
 void msm_gem_move_to_active(struct drm_gem_object *obj,
-		struct msm_gpu *gpu, uint32_t fence)
+		struct msm_gpu *gpu, bool write, uint32_t fence)
 {
 	struct msm_gem_object *msm_obj = to_msm_bo(obj);
 	msm_obj->gpu = gpu;
-	msm_obj->fence = fence;
+	if (write)
+		msm_obj->write_fence = fence;
+	else
+		msm_obj->read_fence = fence;
 	list_del_init(&msm_obj->mm_list);
 	list_add_tail(&msm_obj->mm_list, &gpu->active_list);
 }
@@ -411,7 +414,8 @@ void msm_gem_move_to_inactive(struct drm_gem_object *obj)
 	WARN_ON(!mutex_is_locked(&dev->struct_mutex));
 
 	msm_obj->gpu = NULL;
-	msm_obj->fence = 0;
+	msm_obj->read_fence = 0;
+	msm_obj->write_fence = 0;
 	list_del_init(&msm_obj->mm_list);
 	list_add_tail(&msm_obj->mm_list, &priv->inactive_list);
 
@@ -433,8 +437,14 @@ int msm_gem_cpu_prep(struct drm_gem_object *obj, uint32_t op,
 	struct msm_gem_object *msm_obj = to_msm_bo(obj);
 	int ret = 0;
 
-	if (is_active(msm_obj) && !(op & MSM_PREP_NOSYNC))
-		ret = msm_wait_fence_interruptable(dev, msm_obj->fence, timeout);
+	if (is_active(msm_obj) && !(op & MSM_PREP_NOSYNC)) {
+		uint32_t fence = 0;
+		if (op & MSM_PREP_READ)
+			fence = msm_obj->write_fence;
+		if (op & MSM_PREP_WRITE)
+			fence = max(fence, msm_obj->read_fence);
+		ret = msm_wait_fence_interruptable(dev, fence, timeout);
+	}
 
 	/* TODO cache maintenance */
 
@@ -455,9 +465,10 @@ void msm_gem_describe(struct drm_gem_object *obj, struct seq_file *m)
 	uint64_t off = drm_vma_node_start(&obj->vma_node);
 
 	WARN_ON(!mutex_is_locked(&dev->struct_mutex));
-	seq_printf(m, "%08x: %c(%d) %2d (%2d) %08llx %p %d\n",
+	seq_printf(m, "%08x: %c(r=%u,w=%u) %2d (%2d) %08llx %p %d\n",
 			msm_obj->flags, is_active(msm_obj) ? 'A' : 'I',
-			msm_obj->fence, obj->name, obj->refcount.refcount.counter,
+			msm_obj->read_fence, msm_obj->write_fence,
+			obj->name, obj->refcount.refcount.counter,
 			off, msm_obj->vaddr, obj->size);
 }