[PATCH] drm/amdgpu: Enable gfx cache probing on HDP write for arcturus

[Zeng, Oak]

This allows gfx cache to be probed and invalidated (for none-dirty cache lines)
on a HDP write (from either another GPU or CPU). This should work only for the
memory mapped as RW memory type newly added for arcturus, to achieve some cache
coherence b/t multiple memory clients.

Change-Id: I0a69d0000e48706bb713235bfbc83fcc67774614
Signed-off-by: Oak Zeng <Oak.Zeng at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
index 57d76ee..e01a359 100644
--- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
@@ -1272,6 +1272,9 @@ static int gmc_v9_0_gart_enable(struct amdgpu_device *adev)
 		/* TODO for renoir */
 		mmhub_v1_0_update_power_gating(adev, true);
 		break;
+	case CHIP_ARCTURUS:
+		WREG32_FIELD15(HDP, 0, HDP_MMHUB_CNTL, HDP_MMHUB_GCC, 1);
+		break;
 	default:
 		break;
 	}
-- 
2.7.4