powerpc: Make chip-id information available to userspace

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>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 009900dd8f25..d9d8bb0f4454 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -596,6 +596,21 @@ 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)
 {