Merge branch 'origin'

1 files changed, 21 insertions, 0 deletions

diff --git a/shared-core/nv04_timer.c b/shared-core/nv04_timer.c
index efe78da7..08a27f4f 100644
--- a/shared-core/nv04_timer.c
+++ b/shared-core/nv04_timer.c
@@ -17,6 +17,27 @@ nv04_timer_init(struct drm_device *dev)
 	return 0;
 }
 
+uint64_t
+nv04_timer_read(struct drm_device *dev)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	uint32_t low;
+	/* From kmmio dumps on nv28 this looks like how the blob does this.
+	 * It reads the high dword twice, before and after.
+	 * The only explanation seems to be that the 64-bit timer counter
+	 * advances between high and low dword reads and may corrupt the
+	 * result. Not confirmed.
+	 */
+	uint32_t high2 = NV_READ(NV04_PTIMER_TIME_1);
+	uint32_t high1;
+	do {
+		high1 = high2;
+		low = NV_READ(NV04_PTIMER_TIME_0);
+		high2 = NV_READ(NV04_PTIMER_TIME_1);
+	} while(high1 != high2);
+	return (((uint64_t)high2) << 32) | (uint64_t)low;
+}
+
 void
 nv04_timer_takedown(struct drm_device *dev)
 {