ACPICA: Detect FACS in reduced hardware build

According to Section 5.2.10 of ACPI Specification, FACS is optional
in reduced hardware model. Enable the detection for "Hardware-reduced
ACPI support only" build (CONFIG_ACPI_REDUCED_HARDWARE_ONLY=y) also.

Link: acpica/acpica@ee53ed6
Signed-off-by: Jiaqing Zhao <jiaqing.zhao@linux.intel.com>
Link: https://patch.msgid.link/20240827025821.2099068-2-jiaqing.zhao@linux.intel.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: jiaqingz-dev

drivers/acpi/acpica/acglobal.h

@@ -29,11 +29,7 @@ ACPI_INIT_GLOBAL(u32, acpi_gbl_dsdt_index, ACPI_INVALID_TABLE_INDEX);
 ACPI_INIT_GLOBAL(u32, acpi_gbl_facs_index, ACPI_INVALID_TABLE_INDEX);
 ACPI_INIT_GLOBAL(u32, acpi_gbl_xfacs_index, ACPI_INVALID_TABLE_INDEX);
 ACPI_INIT_GLOBAL(u32, acpi_gbl_fadt_index, ACPI_INVALID_TABLE_INDEX);
-
-#if (!ACPI_REDUCED_HARDWARE)
-ACPI_GLOBAL(struct acpi_table_facs *, acpi_gbl_FACS);
-
-#endif				/* !ACPI_REDUCED_HARDWARE */
+ACPI_INIT_GLOBAL(struct acpi_table_facs *, acpi_gbl_FACS, NULL);
 
 /* These addresses are calculated from the FADT Event Block addresses */
 

drivers/acpi/acpica/tbutils.c

@@ -18,7 +18,6 @@ ACPI_MODULE_NAME("tbutils")
 static acpi_physical_address
 acpi_tb_get_root_table_entry(u8 *table_entry, u32 table_entry_size);
 
-#if (!ACPI_REDUCED_HARDWARE)
 /*******************************************************************************
  *
  * FUNCTION:    acpi_tb_initialize_facs
@@ -56,7 +55,6 @@ acpi_status acpi_tb_initialize_facs(void)
 
 	return (AE_OK);
 }
-#endif				/* !ACPI_REDUCED_HARDWARE */
 
 /*******************************************************************************
  *

drivers/acpi/acpica/utxfinit.c

@@ -120,6 +120,18 @@ acpi_status ACPI_INIT_FUNCTION acpi_enable_subsystem(u32 flags)
 	 */
 	acpi_gbl_early_initialization = FALSE;
 
+	/*
+	 * Obtain a permanent mapping for the FACS. This is required for the
+	 * Global Lock and the Firmware Waking Vector
+	 */
+	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);
+		}
+	}
+
 #if (!ACPI_REDUCED_HARDWARE)
 
 	/* Enable ACPI mode */
@@ -137,18 +149,6 @@ acpi_status ACPI_INIT_FUNCTION acpi_enable_subsystem(u32 flags)
 		}
 	}
 
-	/*
-	 * Obtain a permanent mapping for the FACS. This is required for the
-	 * Global Lock and the Firmware Waking Vector
-	 */
-	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);
-		}
-	}
-
 	/*
 	 * Initialize ACPI Event handling (Fixed and General Purpose)
 	 *

include/acpi/acconfig.h

@@ -67,7 +67,6 @@
  *      General Purpose Events (GPEs)
  *      Global Lock
  *      ACPI PM timer
- *      FACS table (Waking vectors and Global Lock)
  */
 #ifndef ACPI_REDUCED_HARDWARE
 #define ACPI_REDUCED_HARDWARE           FALSE