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/tbfadt.c b/drivers/acpi/acpica/tbfadt.c
index 536fd2b..1e1a7de 100644
--- a/drivers/acpi/acpica/tbfadt.c
+++ b/drivers/acpi/acpica/tbfadt.c
@@ -253,8 +253,13 @@
acpi_tb_install_table((acpi_physical_address) acpi_gbl_FADT.Xdsdt,
ACPI_SIG_DSDT, ACPI_TABLE_INDEX_DSDT);
- acpi_tb_install_table((acpi_physical_address) acpi_gbl_FADT.Xfacs,
- ACPI_SIG_FACS, ACPI_TABLE_INDEX_FACS);
+ /* If Hardware Reduced flag is set, there is no FACS */
+
+ if (!acpi_gbl_reduced_hardware) {
+ acpi_tb_install_table((acpi_physical_address) acpi_gbl_FADT.
+ Xfacs, ACPI_SIG_FACS,
+ ACPI_TABLE_INDEX_FACS);
+ }
}
/*******************************************************************************
@@ -297,6 +302,13 @@
ACPI_MEMCPY(&acpi_gbl_FADT, table,
ACPI_MIN(length, sizeof(struct acpi_table_fadt)));
+ /* Take a copy of the Hardware Reduced flag */
+
+ acpi_gbl_reduced_hardware = FALSE;
+ if (acpi_gbl_FADT.flags & ACPI_FADT_HW_REDUCED) {
+ acpi_gbl_reduced_hardware = TRUE;
+ }
+
/* Convert the local copy of the FADT to the common internal format */
acpi_tb_convert_fadt();
@@ -502,6 +514,12 @@
acpi_gbl_FADT.Xdsdt = (u64) acpi_gbl_FADT.dsdt;
}
+ /* If Hardware Reduced flag is set, we are all done */
+
+ if (acpi_gbl_reduced_hardware) {
+ return;
+ }
+
/* Examine all of the 64-bit extended address fields (X fields) */
for (i = 0; i < ACPI_FADT_INFO_ENTRIES; i++) {