drm/amdgpu/powerplay: check MC firmware for FFC support

Check if the MC firmware supports FFC and tell the SMC so
mclk switching is handled properly.
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c

@@ -4222,9 +4222,17 @@ static int smu7_check_mc_firmware(struct pp_hwmgr *hwmgr)
 	if (tmp & (1 << 23)) {
 		data->mem_latency_high = MEM_LATENCY_HIGH;
 		data->mem_latency_low = MEM_LATENCY_LOW;
+		if ((hwmgr->chip_id == CHIP_POLARIS10) ||
+		    (hwmgr->chip_id == CHIP_POLARIS11) ||
+		    (hwmgr->chip_id == CHIP_POLARIS12))
+			smum_send_msg_to_smc(hwmgr, PPSMC_MSG_EnableFFC);
 	} else {
 		data->mem_latency_high = 330;
 		data->mem_latency_low = 330;
+		if ((hwmgr->chip_id == CHIP_POLARIS10) ||
+		    (hwmgr->chip_id == CHIP_POLARIS11) ||
+		    (hwmgr->chip_id == CHIP_POLARIS12))
+			smum_send_msg_to_smc(hwmgr, PPSMC_MSG_DisableFFC);
 	}
 
 	return 0;