ACPI / processor: Make it possible to get CPU hardware ID via GICC

[cascardo/linux.git] / drivers / acpi / processor_core.c

diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index 51cc299..b1ec78b 100644 (file)
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -83,6 +83,31 @@ static int map_lsapic_id(struct acpi_subtable_header *entry,
        return 0;
 }
 
+/*
+ * Retrieve the ARM CPU physical identifier (MPIDR)
+ */
+static int map_gicc_mpidr(struct acpi_subtable_header *entry,
+               int device_declaration, u32 acpi_id, phys_cpuid_t *mpidr)
+{
+       struct acpi_madt_generic_interrupt *gicc =
+           container_of(entry, struct acpi_madt_generic_interrupt, header);
+
+       if (!(gicc->flags & ACPI_MADT_ENABLED))
+               return -ENODEV;
+
+       /* device_declaration means Device object in DSDT, 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 && (gicc->uid == acpi_id)) {
+               *mpidr = gicc->arm_mpidr;
+               return 0;
+       }
+
+       return -EINVAL;
+}
+
 static phys_cpuid_t map_madt_entry(int type, u32 acpi_id)
 {
        unsigned long madt_end, entry;
@@ -111,6 +136,9 @@ static phys_cpuid_t 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, &phys_id))
                                break;
+               } else if (header->type == ACPI_MADT_TYPE_GENERIC_INTERRUPT) {
+                       if (!map_gicc_mpidr(header, type, acpi_id, &phys_id))
+                               break;
                }
                entry += header->length;
        }
@@ -143,6 +171,8 @@ static phys_cpuid_t map_mat_entry(acpi_handle handle, int type, u32 acpi_id)
                map_lsapic_id(header, type, acpi_id, &phys_id);
        else if (header->type == ACPI_MADT_TYPE_LOCAL_X2APIC)
                map_x2apic_id(header, type, acpi_id, &phys_id);
+       else if (header->type == ACPI_MADT_TYPE_GENERIC_INTERRUPT)
+               map_gicc_mpidr(header, type, acpi_id, &phys_id);
 
 exit:
        kfree(buffer.pointer);