[PATCH] powerpc: Make chip-id information available to userspace

[Vasant Hegde <hegdevasant@linux.vnet.ibm.com>]

So far "/sys/devices/system/cpu/cpuX/topology/physical_package_id"
was always default (-1) on ppc64 architecture.

Now, some systems have an ibm,chip-id property in the cpu nodes in
the device tree. On these systems, we now use this information to
display physical_package_id.

Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Shivaprasad G Bhat <sbhat@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/smp.h      |    1 +
 arch/powerpc/include/asm/topology.h |    1 +
 arch/powerpc/kernel/smp.c           |   15 +++++++++++++++
 3 files changed, 17 insertions(+)

diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h
index ffbaabe..ff21fda 100644
--- a/arch/powerpc/include/asm/smp.h
+++ b/arch/powerpc/include/asm/smp.h
@@ -112,6 +112,7 @@ static inline struct cpumask *cpu_core_mask(int cpu)
 }
 
 extern int cpu_to_core_id(int cpu);
+extern int cpu_to_chip_id(int cpu);
 
 /* Since OpenPIC has only 4 IPIs, we use slightly different message numbers.
  *
diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index 161ab66..89e3ef2 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h
@@ -96,6 +96,7 @@ static inline int prrn_is_enabled(void)
 #ifdef CONFIG_PPC64
 #include <asm/smp.h>
 
+#define topology_physical_package_id(cpu)	(cpu_to_chip_id(cpu))
 #define topology_thread_cpumask(cpu)	(per_cpu(cpu_sibling_map, cpu))
 #define topology_core_cpumask(cpu)	(per_cpu(cpu_core_map, cpu))
 #define topology_core_id(cpu)		(cpu_to_core_id(cpu))
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 076977c..a59e1d3 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -574,6 +574,21 @@ out:
 	return id;
 }

+/* Return the value of the chip-id property corresponding
+ * to the given logical cpu.
+ */
+int cpu_to_chip_id(int cpu)
+{
+	struct device_node *np;
+
+	np = of_get_cpu_node(cpu, NULL);
+	if (!np)
+		return -1;
+
+	of_node_put(np);
+	return of_get_ibm_chip_id(np);
+}
+
 /* Helper routines for cpu to core mapping */
 int cpu_core_index_of_thread(int cpu)
 {