ACPI / processor: Make it possible to get APIC ID via GIC

Introduce a new function map_gic_id() to allow APIC IDs to be obtained
from the GIC Structure introduced by ACPI 5.

Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
[rjw: Subject and changelog]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index 4d91b32..f1dd404 100644 (file)
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -71,6 +71,28 @@ static int map_lsapic_id(struct acpi_subtable_header *entry,
        return 0;
 }
 
+static int map_gic_id(struct acpi_subtable_header *entry,
+               int device_declaration, u32 acpi_id, int *apic_id)
+{
+       struct acpi_madt_generic_interrupt *gic =
+               (struct acpi_madt_generic_interrupt *)entry;
+
+       if (!(gic->flags & ACPI_MADT_ENABLED))
+               return -ENODEV;
+
+       /*
+        * In the GIC interrupt model, logical processors are
+        * required to have a Processor Device object in the DSDT,
+        * so we should check device_declaration here
+        */
+       if (device_declaration && (gic->uid == acpi_id)) {
+               *apic_id = gic->gic_id;
+               return 0;
+       }
+
+       return -EINVAL;
+}
+
 static int map_madt_entry(int type, u32 acpi_id)
 {
        unsigned long madt_end, entry;
@@ -106,6 +128,9 @@ static int map_madt_entry(int type, u32 acpi_id)
                } else if (header->type == ACPI_MADT_TYPE_LOCAL_SAPIC) {
                        if (!map_lsapic_id(header, type, acpi_id, &apic_id))
                                break;
+               } else if (header->type == ACPI_MADT_TYPE_GENERIC_INTERRUPT) {
+                       if (!map_gic_id(header, type, acpi_id, &apic_id))
+                               break;
                }
                entry += header->length;
        }
@@ -136,6 +161,8 @@ static int map_mat_entry(acpi_handle handle, int type, u32 acpi_id)
                map_lapic_id(header, acpi_id, &apic_id);
        } else if (header->type == ACPI_MADT_TYPE_LOCAL_SAPIC) {
                map_lsapic_id(header, type, acpi_id, &apic_id);
+       } else if (header->type == ACPI_MADT_TYPE_GENERIC_INTERRUPT) {
+               map_gic_id(header, type, acpi_id, &apic_id);
        }
 
 exit: