drm/msm/gpu: Add submit queue queries

Add the capability to query information from a submit queue.
The first available parameter is for querying the number of GPU faults
(hangs) that can be attributed to the queue.

This is useful for implementing context robustness. A user context can
regularly query the number of faults to see if it is responsible for any
and if so it can invalidate itself.

This is also helpful for testing by confirming to the user  driver if a
particular command stream caused a fault (or not as the case may be).

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>

1 files changed, 41 insertions, 0 deletions

diff --git a/drivers/gpu/drm/msm/msm_submitqueue.c b/drivers/gpu/drm/msm/msm_submitqueue.c
index 5115f75b5b7f..f160ec40a39b 100644
--- a/drivers/gpu/drm/msm/msm_submitqueue.c
+++ b/drivers/gpu/drm/msm/msm_submitqueue.c
@@ -120,6 +120,47 @@ int msm_submitqueue_init(struct drm_device *drm, struct msm_file_private *ctx)
 	return msm_submitqueue_create(drm, ctx, default_prio, 0, NULL);
 }
 
+static int msm_submitqueue_query_faults(struct msm_gpu_submitqueue *queue,
+		struct drm_msm_submitqueue_query *args)
+{
+	size_t size = min_t(size_t, args->len, sizeof(queue->faults));
+	int ret;
+
+	/* If a zero length was passed in, return the data size we expect */
+	if (!args->len) {
+		args->len = sizeof(queue->faults);
+		return 0;
+	}
+
+	/* Set the length to the actual size of the data */
+	args->len = size;
+
+	ret = copy_to_user(u64_to_user_ptr(args->data), &queue->faults, size);
+
+	return ret ? -EFAULT : 0;
+}
+
+int msm_submitqueue_query(struct drm_device *drm, struct msm_file_private *ctx,
+		struct drm_msm_submitqueue_query *args)
+{
+	struct msm_gpu_submitqueue *queue;
+	int ret = -EINVAL;
+
+	if (args->pad)
+		return -EINVAL;
+
+	queue = msm_submitqueue_get(ctx, args->id);
+	if (!queue)
+		return -ENOENT;
+
+	if (args->param == MSM_SUBMITQUEUE_PARAM_FAULTS)
+		ret = msm_submitqueue_query_faults(queue, args);
+
+	msm_submitqueue_put(queue);
+
+	return ret;
+}
+
 int msm_submitqueue_remove(struct msm_file_private *ctx, u32 id)
 {
 	struct msm_gpu_submitqueue *entry;