1 files changed, 43 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 629023240ece..483455c5bb02 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -2105,3 +2105,46 @@ int prom_update_property(struct device_node *np,
         return 0;
 }
 
+
+/* Find the device node for a given logical cpu number, also returns the cpu
+ * local thread number (index in ibm,interrupt-server#s) if relevant and
+ * asked for (non NULL)
+ */
+struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
+{
+        int hardid;
+        struct device_node *np;
+
+        hardid = get_hard_smp_processor_id(cpu);
+
+        for_each_node_by_type(np, "cpu") {
+                u32 *intserv;
+                unsigned int plen, t;
+
+                /* Check for ibm,ppc-interrupt-server#s. If it doesn't exist
+                 * fallback to "reg" property and assume no threads
+                 */
+                intserv = (u32 *)get_property(np, "ibm,ppc-interrupt-server#s",
+                                              &plen);
+                if (intserv == NULL) {
+                        u32 *reg = (u32 *)get_property(np, "reg", NULL);
+                        if (reg == NULL)
+                                continue;
+                        if (*reg == hardid) {
+                                if (thread)
+                                        *thread = 0;
+                                return np;
+                        }
+                } else {
+                        plen /= sizeof(u32);
+                        for (t = 0; t < plen; t++) {
+                                if (hardid == intserv[t]) {
+                                        if (thread)
+                                                *thread = t;
+                                        return np;
+                                }
+                        }
+                }
+        }
+        return NULL;
+}