drm/i915/bdw: Ring idle and stop with logical rings

This is a hard one, since there is no direct hardware ring to
control when in Execlists.

We reuse intel_ring_idle here, but it should be fine as long
as i915_add_request does the ring thing.
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_lrc.c

@@ -105,7 +105,24 @@ int intel_execlists_submission(struct drm_device *dev, struct drm_file *file,
 
 void intel_logical_ring_stop(struct intel_engine_cs *ring)
 {
-	/* TODO */
+	struct drm_i915_private *dev_priv = ring->dev->dev_private;
+	int ret;
+
+	if (!intel_ring_initialized(ring))
+		return;
+
+	ret = intel_ring_idle(ring);
+	if (ret && !i915_reset_in_progress(&to_i915(ring->dev)->gpu_error))
+		DRM_ERROR("failed to quiesce %s whilst cleaning up: %d\n",
+			  ring->name, ret);
+
+	/* TODO: Is this correct with Execlists enabled? */
+	I915_WRITE_MODE(ring, _MASKED_BIT_ENABLE(STOP_RING));
+	if (wait_for_atomic((I915_READ_MODE(ring) & MODE_IDLE) != 0, 1000)) {
+		DRM_ERROR("%s :timed out trying to stop ring\n", ring->name);
+		return;
+	}
+	I915_WRITE_MODE(ring, _MASKED_BIT_DISABLE(STOP_RING));
 }
 
 void intel_logical_ring_advance_and_submit(struct intel_ringbuffer *ringbuf)
@@ -458,10 +475,13 @@ static int gen8_emit_request(struct intel_ringbuffer *ringbuf)
 
 void intel_logical_ring_cleanup(struct intel_engine_cs *ring)
 {
+	struct drm_i915_private *dev_priv = ring->dev->dev_private;
+
 	if (!intel_ring_initialized(ring))
 		return;
 
-	/* TODO: make sure the ring is stopped */
+	intel_logical_ring_stop(ring);
+	WARN_ON((I915_READ_MODE(ring) & MODE_IDLE) == 0);
 	ring->preallocated_lazy_request = NULL;
 	ring->outstanding_lazy_seqno = 0;