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>

1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/acpi/acpica/evevent.c b/drivers/acpi/acpica/evevent.c
index d458b041e651..1f43be470199 100644
--- a/drivers/acpi/acpica/evevent.c
+++ b/drivers/acpi/acpica/evevent.c
@@ -71,6 +71,12 @@ acpi_status acpi_ev_initialize_events(void)
 
         ACPI_FUNCTION_TRACE(ev_initialize_events);
 
+        /* If Hardware Reduced flag is set, there are no fixed events */
+
+        if (acpi_gbl_reduced_hardware) {
+                return_ACPI_STATUS(AE_OK);
+        }
+
         /*
          * Initialize the Fixed and General Purpose Events. This is done prior to
          * enabling SCIs to prevent interrupts from occurring before the handlers
@@ -111,6 +117,12 @@ acpi_status acpi_ev_install_xrupt_handlers(void)
 
         ACPI_FUNCTION_TRACE(ev_install_xrupt_handlers);
 
+        /* If Hardware Reduced flag is set, there is no ACPI h/w */
+
+        if (acpi_gbl_reduced_hardware) {
+                return_ACPI_STATUS(AE_OK);
+        }
+
         /* Install the SCI handler */
 
         status = acpi_ev_install_sci_handler();