drm/amd: Add HDP flush during jpeg init

During jpeg init, CPU writes to frame buffer which can be cached by HDP,
occasionally causing invalid header to be sent to MMSCH.  Perform HDP flush
after writing to frame buffer before continuing with jpeg init sequence.
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Timmy Tsai <timmtsai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/jpeg_v4_0.c

@@ -468,6 +468,9 @@ static int jpeg_v4_0_start_sriov(struct amdgpu_device *adev)
 	table_loc = (uint32_t *)table->cpu_addr;
 	memcpy((void *)table_loc, &header, size);
 
+	/* Perform HDP flush before writing to MMSCH registers */
+	amdgpu_device_flush_hdp(adev, NULL);
+
 	/* message MMSCH (in VCN[0]) to initialize this client
 	 * 1, write to mmsch_vf_ctx_addr_lo/hi register with GPU mc addr
 	 * of memory descriptor location