drm/xe/oa: Separate batch submission from waiting for completion

When we introduce xe_syncs, we don't wait for internal OA programming
batches to complete. That is, xe_syncs are signaled asynchronously. In
anticipation for this, separate out batch submission from waiting for
completion of those batches.

v2: Change return type of xe_oa_submit_bb to "struct dma_fence *" (Matt B)
v3: Retain init "int err = 0;" in xe_oa_submit_bb (Jose)

Reviewed-by: Jonathan Cavitt <[email protected]>
Signed-off-by: Ashutosh Dixit <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

Author: ashutoshx

drivers/gpu/drm/xe/xe_oa.c

@@ -570,11 +570,10 @@ static __poll_t xe_oa_poll(struct file *file, poll_table *wait)
 	return ret;
 }
 
-static int xe_oa_submit_bb(struct xe_oa_stream *stream, struct xe_bb *bb)
+static struct dma_fence *xe_oa_submit_bb(struct xe_oa_stream *stream, struct xe_bb *bb)
 {
 	struct xe_sched_job *job;
 	struct dma_fence *fence;
-	long timeout;
 	int err = 0;
 
 	/* Kernel configuration is issued on stream->k_exec_q, not stream->exec_q */
@@ -588,14 +587,9 @@ static int xe_oa_submit_bb(struct xe_oa_stream *stream, struct xe_bb *bb)
 	fence = dma_fence_get(&job->drm.s_fence->finished);
 	xe_sched_job_push(job);
 
-	timeout = dma_fence_wait_timeout(fence, false, HZ);
-	dma_fence_put(fence);
-	if (timeout < 0)
-		err = timeout;
-	else if (!timeout)
-		err = -ETIME;
+	return fence;
 exit:
-	return err;
+	return ERR_PTR(err);
 }
 
 static void write_cs_mi_lri(struct xe_bb *bb, const struct xe_oa_reg *reg_data, u32 n_regs)
@@ -659,6 +653,7 @@ static void xe_oa_store_flex(struct xe_oa_stream *stream, struct xe_lrc *lrc,
 static int xe_oa_modify_ctx_image(struct xe_oa_stream *stream, struct xe_lrc *lrc,
 				  const struct flex *flex, u32 count)
 {
+	struct dma_fence *fence;
 	struct xe_bb *bb;
 	int err;
 
@@ -670,14 +665,24 @@ static int xe_oa_modify_ctx_image(struct xe_oa_stream *stream, struct xe_lrc *lr
 
 	xe_oa_store_flex(stream, lrc, bb, flex, count);
 
-	err = xe_oa_submit_bb(stream, bb);
+	fence = xe_oa_submit_bb(stream, bb);
+	if (IS_ERR(fence)) {
+		err = PTR_ERR(fence);
+		goto free_bb;
+	}
+	xe_bb_free(bb, fence);
+	dma_fence_put(fence);
+
+	return 0;
+free_bb:
 	xe_bb_free(bb, NULL);
 exit:
 	return err;
 }
 
 static int xe_oa_load_with_lri(struct xe_oa_stream *stream, struct xe_oa_reg *reg_lri)
 {
+	struct dma_fence *fence;
 	struct xe_bb *bb;
 	int err;
 
@@ -689,7 +694,16 @@ static int xe_oa_load_with_lri(struct xe_oa_stream *stream, struct xe_oa_reg *re
 
 	write_cs_mi_lri(bb, reg_lri, 1);
 
-	err = xe_oa_submit_bb(stream, bb);
+	fence = xe_oa_submit_bb(stream, bb);
+	if (IS_ERR(fence)) {
+		err = PTR_ERR(fence);
+		goto free_bb;
+	}
+	xe_bb_free(bb, fence);
+	dma_fence_put(fence);
+
+	return 0;
+free_bb:
 	xe_bb_free(bb, NULL);
 exit:
 	return err;
@@ -919,15 +933,32 @@ static int xe_oa_emit_oa_config(struct xe_oa_stream *stream, struct xe_oa_config
 {
 #define NOA_PROGRAM_ADDITIONAL_DELAY_US 500
 	struct xe_oa_config_bo *oa_bo;
-	int err, us = NOA_PROGRAM_ADDITIONAL_DELAY_US;
+	int err = 0, us = NOA_PROGRAM_ADDITIONAL_DELAY_US;
+	struct dma_fence *fence;
+	long timeout;
 
+	/* Emit OA configuration batch */
 	oa_bo = xe_oa_alloc_config_buffer(stream, config);
 	if (IS_ERR(oa_bo)) {
 		err = PTR_ERR(oa_bo);
 		goto exit;
 	}
 
-	err = xe_oa_submit_bb(stream, oa_bo->bb);
+	fence = xe_oa_submit_bb(stream, oa_bo->bb);
+	if (IS_ERR(fence)) {
+		err = PTR_ERR(fence);
+		goto exit;
+	}
+
+	/* Wait till all previous batches have executed */
+	timeout = dma_fence_wait_timeout(fence, false, 5 * HZ);
+	dma_fence_put(fence);
+	if (timeout < 0)
+		err = timeout;
+	else if (!timeout)
+		err = -ETIME;
+	if (err)
+		drm_dbg(&stream->oa->xe->drm, "dma_fence_wait_timeout err %d\n", err);
 
 	/* Additional empirical delay needed for NOA programming after registers are written */
 	usleep_range(us, 2 * us);