drm/radeon/evergreen/btc/fusion: setup hdp to invalidate and flush when asked

This needs to be explicitly set on btc.  It's set by default
on evergreen/fusion, so it fine to just unconditionally enable it for
all chips.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@gmail.com>
diff --git a/drivers/gpu/drm/radeon/evergreen.c b/drivers/gpu/drm/radeon/evergreen.c
index c20eac3..864e853 100644
--- a/drivers/gpu/drm/radeon/evergreen.c
+++ b/drivers/gpu/drm/radeon/evergreen.c
@@ -1578,7 +1578,7 @@
 	u32 sq_stack_resource_mgmt_2;
 	u32 sq_stack_resource_mgmt_3;
 	u32 vgt_cache_invalidation;
-	u32 hdp_host_path_cntl;
+	u32 hdp_host_path_cntl, tmp;
 	int i, j, num_shader_engines, ps_thread_count;
 
 	switch (rdev->family) {
@@ -2138,6 +2138,10 @@
 	for (i = SQ_ALU_CONST_BUFFER_SIZE_HS_0; i < 0x29000; i += 4)
 		WREG32(i, 0);
 
+	tmp = RREG32(HDP_MISC_CNTL);
+	tmp |= HDP_FLUSH_INVALIDATE_CACHE;
+	WREG32(HDP_MISC_CNTL, tmp);
+
 	hdp_host_path_cntl = RREG32(HDP_HOST_PATH_CNTL);
 	WREG32(HDP_HOST_PATH_CNTL, hdp_host_path_cntl);