drm/amdgpu/si: load special ucode for certain MC configs

Special MC ucode is required for these memory configurations.
Acked-by: Edward O'Callaghan <funfunctor@folklore1984.net>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c

@@ -44,6 +44,7 @@ MODULE_FIRMWARE("radeon/tahiti_mc.bin");
 MODULE_FIRMWARE("radeon/pitcairn_mc.bin");
 MODULE_FIRMWARE("radeon/verde_mc.bin");
 MODULE_FIRMWARE("radeon/oland_mc.bin");
+MODULE_FIRMWARE("radeon/si58_mc.bin");
 
 #define MC_SEQ_MISC0__MT__MASK   0xf0000000
 #define MC_SEQ_MISC0__MT__GDDR1  0x10000000
@@ -113,6 +114,7 @@ static int gmc_v6_0_init_microcode(struct amdgpu_device *adev)
 	const char *chip_name;
 	char fw_name[30];
 	int err;
+	bool is_58_fw = false;
 
 	DRM_DEBUG("\n");
 
@@ -135,6 +137,13 @@ static int gmc_v6_0_init_microcode(struct amdgpu_device *adev)
 	default: BUG();
 	}
 
+	/* this memory configuration requires special firmware */
+	if (((RREG32(mmMC_SEQ_MISC0) & 0xff000000) >> 24) == 0x58)
+		is_58_fw = true;
+
+	if (is_58_fw)
+		snprintf(fw_name, sizeof(fw_name), "radeon/si58_mc.bin");
+	else
 		snprintf(fw_name, sizeof(fw_name), "radeon/%s_mc.bin", chip_name);
 	err = request_firmware(&adev->mc.fw, fw_name, adev->dev);
 	if (err)