drm/radeon: make forcing ring activity a common function

Nothing chipset or ring specific with it,
so also move it to radon_ring.

Signed-off-by: Christian König <deathsimple@vodafone.de>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_ring.c b/drivers/gpu/drm/radeon/radeon_ring.c
index 407d90a..2eb4c6e 100644
--- a/drivers/gpu/drm/radeon/radeon_ring.c
+++ b/drivers/gpu/drm/radeon/radeon_ring.c
@@ -398,6 +398,22 @@
 	mutex_unlock(&ring->mutex);
 }
 
+void radeon_ring_force_activity(struct radeon_device *rdev, struct radeon_ring *ring)
+{
+	int r;
+
+	mutex_lock(&ring->mutex);
+	radeon_ring_free_size(rdev, ring);
+	if (ring->rptr == ring->wptr) {
+		r = radeon_ring_alloc(rdev, ring, 1);
+		if (!r) {
+			radeon_ring_write(ring, ring->nop);
+			radeon_ring_commit(rdev, ring);
+		}
+	}
+	mutex_unlock(&ring->mutex);
+}
+
 void radeon_ring_lockup_update(struct radeon_ring *ring)
 {
 	ring->last_rptr = ring->rptr;