AMD Hudson: enable IMC fan control using ACPI code

IMC fan control should be enabled after OS launched.
I have tested on OliveHill and Parmer with Windows 7 and Ubuntu 13.10.

Change-Id: I16d6ff6b1272d16b840e803e0a95f6e363c79704
Signed-off-by: WANG Siyuan <SiYuan.Wang@amd.com>
Signed-off-by: WANG Siyuan <wangsiyuanbuaa@gmail.com>
Reviewed-on: http://review.coreboot.org/7165
Tested-by: build bot (Jenkins)
Reviewed-by: Bruce Griffith <Bruce.Griffith@se-eng.com>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>

src/southbridge/amd/agesa/hudson/Kconfig

@@ -244,6 +244,10 @@ config HUDSON_LEGACY_FREE
 	  Select y if there is no keyboard controller in the system.
 	  This sets variables in AGESA and ACPI.
 
+config ACPI_ENABLE_THERMAL_ZONE
+	bool
+	default y
+
 endif # SOUTHBRIDGE_AMD_AGESA_HUDSON || SOUTHBRIDGE_AMD_AGESA_YANGTZE || SOUTHBRIDGE_AMD_AGESA_AVALON
 
 if SOUTHBRIDGE_AMD_AGESA_YANGTZE || SOUTHBRIDGE_AMD_AGESA_AVALON

src/southbridge/amd/agesa/hudson/acpi/fch.asl

@@ -179,9 +179,12 @@ Method(_INI, 0) {
 	/* Determine the OS we're running on */
 	OSFL()
 
-	/* TODO: It is unstable. */
-	//#include "acpi/AmdImc.asl" /* Hudson IMC function */
-	//ITZE() /* enable IMC Fan Control*/
+#ifdef CONFIG_HUDSON_IMC_FWM
+#if CONFIG_HUDSON_IMC_FWM
+	#include "acpi/AmdImc.asl" /* Hudson IMC function */
+	ITZE() /* enable IMC Fan Control*/
+#endif
+#endif
 } /* End Method(_SB._INI) */
 
 Method(OSFL, 0){

src/southbridge/amd/agesa/hudson/hudson.c

@@ -164,10 +164,12 @@ static void hudson_init(void *chip_info)
 
 static void hudson_final(void *chip_info)
 {
+#if !CONFIG_ACPI_ENABLE_THERMAL_ZONE
 #if IS_ENABLED(CONFIG_HUDSON_IMC_FWM)
 	/* AMD AGESA does not enable thermal zone, so we enable it here. */
 	enable_imc_thermal_zone();
 #endif
+#endif
 }
 
 struct chip_operations southbridge_amd_agesa_hudson_ops = {