powerpc/pseries: Add kernel based CPU DLPAR handling

This patch adds the specific routines to probe and release (add and remove)
cpu resource for the powerpc pseries platform and registers these handlers
with the ppc_md callout structure.
Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/pseries/dlpar.c

@@ -341,4 +341,92 @@ int dlpar_release_drc(u32 drc_index)
 	return 0;
 }
 
+#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
 
+static ssize_t dlpar_cpu_probe(const char *buf, size_t count)
+{
+	struct device_node *dn;
+	unsigned long drc_index;
+	char *cpu_name;
+	int rc;
+
+	rc = strict_strtoul(buf, 0, &drc_index);
+	if (rc)
+		return -EINVAL;
+
+	dn = dlpar_configure_connector(drc_index);
+	if (!dn)
+		return -EINVAL;
+
+	/* configure-connector reports cpus as living in the base
+	 * directory of the device tree.  CPUs actually live in the
+	 * cpus directory so we need to fixup the full_name.
+	 */
+	cpu_name = kzalloc(strlen(dn->full_name) + strlen("/cpus") + 1,
+			   GFP_KERNEL);
+	if (!cpu_name) {
+		dlpar_free_cc_nodes(dn);
+		return -ENOMEM;
+	}
+
+	sprintf(cpu_name, "/cpus%s", dn->full_name);
+	kfree(dn->full_name);
+	dn->full_name = cpu_name;
+
+	rc = dlpar_acquire_drc(drc_index);
+	if (rc) {
+		dlpar_free_cc_nodes(dn);
+		return -EINVAL;
+	}
+
+	rc = dlpar_attach_node(dn);
+	if (rc) {
+		dlpar_release_drc(drc_index);
+		dlpar_free_cc_nodes(dn);
+	}
+
+	return rc ? rc : count;
+}
+
+static ssize_t dlpar_cpu_release(const char *buf, size_t count)
+{
+	struct device_node *dn;
+	const u32 *drc_index;
+	int rc;
+
+	dn = of_find_node_by_path(buf);
+	if (!dn)
+		return -EINVAL;
+
+	drc_index = of_get_property(dn, "ibm,my-drc-index", NULL);
+	if (!drc_index) {
+		of_node_put(dn);
+		return -EINVAL;
+	}
+
+	rc = dlpar_release_drc(*drc_index);
+	if (rc) {
+		of_node_put(dn);
+		return -EINVAL;
+	}
+
+	rc = dlpar_detach_node(dn);
+	if (rc) {
+		dlpar_acquire_drc(*drc_index);
+		return rc;
+	}
+
+	of_node_put(dn);
+	return count;
+}
+
+static int __init pseries_dlpar_init(void)
+{
+	ppc_md.cpu_probe = dlpar_cpu_probe;
+	ppc_md.cpu_release = dlpar_cpu_release;
+
+	return 0;
+}
+machine_device_initcall(pseries, pseries_dlpar_init);
+
+#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */