drm: radeon: implement RADEON_PARAM_SCRATCH_OFFSET getparam
When this succeeds, userspace can read the scratch register contents from th mapped writeback page directly.
Signed-off-by: Dave Airlie <airlied@linux.ie>
diff --git a/drivers/char/drm/radeon_state.c b/drivers/char/drm/radeon_state.c
index 99589fe..0433ff8 100644
--- a/drivers/char/drm/radeon_state.c
+++ b/drivers/char/drm/radeon_state.c
@@ -2987,7 +2987,11 @@
case RADEON_PARAM_GART_TEX_HANDLE:
value = dev_priv->gart_textures_offset;
break;
-
+ case RADEON_PARAM_SCRATCH_OFFSET:
+ if (!dev_priv->writeback_works)
+ return DRM_ERR(EINVAL);
+ value = RADEON_SCRATCH_REG_OFFSET;
+ break;
case RADEON_PARAM_CARD_TYPE:
if (dev_priv->flags & CHIP_IS_PCIE)
value = RADEON_CARD_PCIE;