[PATCH v9 14/21] ACPI / processor: Make it possible to get CPU hardware ID via GICC

[Hanjun Guo]

Introduce a new function map_gicc_mpidr() to allow MPIDRs to be obtained
from the GICC Structure introduced by ACPI 5.1.

The ARM architecture defines the MPIDR register as the CPU hardware
identifier. This patch adds the code infrastructure to retrieve the MPIDR
values from the ARM ACPI GICC structure in order to look-up the kernel CPU
hardware ids required by the ACPI core code to identify CPUs.

CC: Rafael J. Wysocki <rjw at rjwysocki.net>
CC: Catalin Marinas <catalin.marinas at arm.com>
CC: Will Deacon <will.deacon at arm.com>
Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit at amd.com>
Tested-by: Yijing Wang <wangyijing at huawei.com>
Tested-by: Mark Langsdorf <mlangsdo at redhat.com>
Tested-by: Jon Masters <jcm at redhat.com>
Tested-by: Timur Tabi <timur at codeaurora.org>
Tested-by: Robert Richter <rrichter at cavium.com>
Acked-by: Robert Richter <rrichter at cavium.com>
Signed-off-by: Hanjun Guo <hanjun.guo at linaro.org>
---
 arch/arm64/include/asm/acpi.h | 12 ++++++++++++
 drivers/acpi/processor_core.c | 30 ++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index 9719921..9a23369 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -13,6 +13,8 @@
 #define _ASM_ACPI_H
 
 #include <linux/mm.h>
+#include <asm/cputype.h>
+#include <asm/smp_plat.h>
 
 /* Basic configuration for ACPI */
 #ifdef	CONFIG_ACPI
@@ -27,6 +29,9 @@ static inline void __iomem *acpi_os_ioremap(acpi_physical_address phys,
 }
 #define acpi_os_ioremap acpi_os_ioremap
 
+typedef u64 phys_cpuid_t;
+#define CPU_PHYS_ID_INVALID INVALID_HWID
+
 #define acpi_strict 1	/* No out-of-spec workarounds on ARM64 */
 extern int acpi_disabled;
 extern int acpi_noirq;
@@ -59,6 +64,13 @@ static inline void enable_acpi(void)
 }
 
 /*
+ * The ACPI processor driver for ACPI core code needs this macro
+ * to find out this cpu was already mapped (mapping from CPU hardware
+ * ID to CPU logical ID) or not.
+ */
+#define cpu_physical_id(cpu) cpu_logical_map(cpu)
+
+/*
  * It's used from ACPI core in kdump to boot UP system with SMP kernel,
  * with this check the ACPI core will not override the CPU index
  * obtained from GICC with 0 and not print some error message as well.
diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index a5547dc..8654adb 100644
--- 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);
-- 
1.9.1