[PATCH] powerpc: Allow devices to register with numa topology

Change of_node_to_nid() to traverse the device tree, looking for a numa id.
Cell uses this to assign ids to SPUs, which are children of the CPU node.
Existing users of of_node_to_nid() are altered to use of_node_to_nid_single(),
which doesn't do the traversal.

Export an attach_sysdev_to_node() function, allowing system devices (eg.
SPUs) to link themselves into the numa topology in sysfs.
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/powerpc/kernel/sysfs.c

@@ -322,13 +322,31 @@ static void register_nodes(void)
 		}
 	}
 }
+
+int sysfs_add_device_to_node(struct sys_device *dev, int nid)
+{
+	struct node *node = &node_devices[nid];
+	return sysfs_create_link(&node->sysdev.kobj, &dev->kobj,
+			kobject_name(&dev->kobj));
+}
+
+void sysfs_remove_device_from_node(struct sys_device *dev, int nid)
+{
+	struct node *node = &node_devices[nid];
+	sysfs_remove_link(&node->sysdev.kobj, kobject_name(&dev->kobj));
+}
+
 #else
 static void register_nodes(void)
 {
 	return;
 }
+
 #endif
 
+EXPORT_SYMBOL_GPL(sysfs_add_device_to_node);
+EXPORT_SYMBOL_GPL(sysfs_remove_device_from_node);
+
 /* Only valid if CPU is present. */
 static ssize_t show_physical_id(struct sys_device *dev, char *buf)
 {

arch/powerpc/mm/numa.c

@@ -194,7 +194,7 @@ static int *of_get_associativity(struct device_node *dev)
 /* Returns nid in the range [0..MAX_NUMNODES-1], or -1 if no useful numa
  * info is found.
  */
-static int of_node_to_nid(struct device_node *device)
+static int of_node_to_nid_single(struct device_node *device)
 {
 	int nid = -1;
 	unsigned int *tmp;
@@ -216,6 +216,28 @@ static int of_node_to_nid(struct device_node *device)
 	return nid;
 }
 
+/* Walk the device tree upwards, looking for an associativity id */
+int of_node_to_nid(struct device_node *device)
+{
+	struct device_node *tmp;
+	int nid = -1;
+
+	of_node_get(device);
+	while (device) {
+		nid = of_node_to_nid_single(device);
+		if (nid != -1)
+			break;
+
+	        tmp = device;
+		device = of_get_parent(tmp);
+		of_node_put(tmp);
+	}
+	of_node_put(device);
+
+	return nid;
+}
+EXPORT_SYMBOL_GPL(of_node_to_nid);
+
 /*
  * In theory, the "ibm,associativity" property may contain multiple
  * associativity lists because a resource may be multiply connected
@@ -300,7 +322,7 @@ static int __cpuinit numa_setup_cpu(unsigned long lcpu)
 		goto out;
 	}
 
-	nid = of_node_to_nid(cpu);
+	nid = of_node_to_nid_single(cpu);
 
 	if (nid < 0 || !node_online(nid))
 		nid = any_online_node(NODE_MASK_ALL);
@@ -393,7 +415,7 @@ static int __init parse_numa_properties(void)
 
 		cpu = find_cpu_node(i);
 		BUG_ON(!cpu);
-		nid = of_node_to_nid(cpu);
+		nid = of_node_to_nid_single(cpu);
 		of_node_put(cpu);
 
 		/*
@@ -437,7 +459,7 @@ static int __init parse_numa_properties(void)
 		 * have associativity properties.  If none, then
 		 * everything goes to default_nid.
 		 */
-		nid = of_node_to_nid(memory);
+		nid = of_node_to_nid_single(memory);
 		if (nid < 0)
 			nid = default_nid;
 		node_set_online(nid);
@@ -776,7 +798,7 @@ int hot_add_scn_to_nid(unsigned long scn_addr)
 ha_new_range:
 		start = read_n_cells(n_mem_addr_cells, &memcell_buf);
 		size = read_n_cells(n_mem_size_cells, &memcell_buf);
-		nid = of_node_to_nid(memory);
+		nid = of_node_to_nid_single(memory);
 
 		/* Domains not present at boot default to 0 */
 		if (nid < 0 || !node_online(nid))

include/asm-powerpc/topology.h

@@ -4,6 +4,9 @@
 
 #include <linux/config.h>
 
+struct sys_device;
+struct device_node;
+
 #ifdef CONFIG_NUMA
 
 #include <asm/mmzone.h>
@@ -27,6 +30,8 @@ static inline int node_to_first_cpu(int node)
 	return first_cpu(tmp);
 }
 
+int of_node_to_nid(struct device_node *device);
+
 #define pcibus_to_node(node)    (-1)
 #define pcibus_to_cpumask(bus)	(cpu_online_map)
 
@@ -57,10 +62,29 @@ static inline int node_to_first_cpu(int node)
 
 extern void __init dump_numa_cpu_topology(void);
 
+extern int sysfs_add_device_to_node(struct sys_device *dev, int nid);
+extern void sysfs_remove_device_from_node(struct sys_device *dev, int nid);
+
 #else
 
+static inline int of_node_to_nid(struct device_node *device)
+{
+	return 0;
+}
+
 static inline void dump_numa_cpu_topology(void) {}
 
+static inline int sysfs_add_device_to_node(struct sys_device *dev, int nid)
+{
+	return 0;
+}
+
+static inline void sysfs_remove_device_from_node(struct sys_device *dev,
+						int nid)
+{
+}
+
+
 #include <asm-generic/topology.h>
 
 #endif /* CONFIG_NUMA */