ACPICA: Tables: Fix an issue that FACS initialization is performed twice

commit c04be184 upstream.

ACPICA commit 90f5332a15e9d9ba83831ca700b2b9f708274658

This patch adds a new FACS initialization flag for acpi_tb_initialize().
acpi_enable_subsystem() might be invoked several times in OS bootup process,
and we don't want FACS initialization to be invoked twice. Lv Zheng.

Link: https://github.com/acpica/acpica/commit/90f5332aSigned-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/acpi/acpica/utxface.c

@@ -163,10 +163,12 @@ acpi_status acpi_enable_subsystem(u32 flags)
 	 * Obtain a permanent mapping for the FACS. This is required for the
 	 * Global Lock and the Firmware Waking Vector
 	 */
-	status = acpi_tb_initialize_facs();
-	if (ACPI_FAILURE(status)) {
-		ACPI_WARNING((AE_INFO, "Could not map the FACS table"));
-		return_ACPI_STATUS(status);
+	if (!(flags & ACPI_NO_FACS_INIT)) {
+		status = acpi_tb_initialize_facs();
+		if (ACPI_FAILURE(status)) {
+			ACPI_WARNING((AE_INFO, "Could not map the FACS table"));
+			return_ACPI_STATUS(status);
+		}
 	}
 
 	/*

include/acpi/actypes.h

@@ -495,6 +495,7 @@ typedef u64 acpi_integer;
 #define ACPI_NO_ACPI_ENABLE             0x10
 #define ACPI_NO_DEVICE_INIT             0x20
 #define ACPI_NO_OBJECT_INIT             0x40
+#define ACPI_NO_FACS_INIT               0x80
 
 /*
  * Initialization state