ACPI 5.0: Implement hardware-reduced option

If HW-reduced flag is set in the FADT, do not attempt to access
or initialize any ACPI hardware, including SCI and global lock.
No FACS will be present.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/acpica/tbutils.c b/drivers/acpi/acpica/tbutils.c
index 0f2d395..da56a19 100644
--- a/drivers/acpi/acpica/tbutils.c
+++ b/drivers/acpi/acpica/tbutils.c
@@ -135,6 +135,13 @@
 {
 	acpi_status status;
 
+	/* If Hardware Reduced flag is set, there is no FACS */
+
+	if (acpi_gbl_reduced_hardware) {
+		acpi_gbl_FACS = NULL;
+		return (AE_OK);
+	}
+
 	status = acpi_get_table_by_index(ACPI_TABLE_INDEX_FACS,
 					 ACPI_CAST_INDIRECT_PTR(struct
 								acpi_table_header,