drm/i915: Add intel_ring_cachline_align()

[pandora-kernel.git] / drivers / gpu / drm / i915 / intel_ringbuffer.c

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 3c55cf6..8ee068e 100644 (file)
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1213,6 +1213,27 @@ int intel_ring_begin(struct intel_ring_buffer *ring,
        return 0;
 }
 
+/* Align the ring tail to a cacheline boundary */
+int intel_ring_cacheline_align(struct intel_ring_buffer *ring)
+{
+       int num_dwords = (64 - (ring->tail & 63)) / sizeof(uint32_t);
+       int ret;
+
+       if (num_dwords == 0)
+               return 0;
+
+       ret = intel_ring_begin(ring, num_dwords);
+       if (ret)
+               return ret;
+
+       while (num_dwords--)
+               intel_ring_emit(ring, MI_NOOP);
+
+       intel_ring_advance(ring);
+
+       return 0;
+}
+
 void intel_ring_advance(struct intel_ring_buffer *ring)
 {
        ring->tail &= ring->size - 1;