powerpc/powernv: Enable reading and updating of system parameters
This patch enables reading and updating of system parameters through
OPAL call.
Signed-off-by: Neelesh Gupta <neelegup@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/platforms/powernv/opal-sysparam.c b/arch/powerpc/platforms/powernv/opal-sysparam.c
new file mode 100644
index 0000000..0bd249a
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-sysparam.c
@@ -0,0 +1,290 @@
+/*
+ * PowerNV system parameter code
+ *
+ * Copyright (C) 2013 IBM
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/kobject.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/gfp.h>
+#include <linux/stat.h>
+#include <asm/opal.h>
+
+#define MAX_PARAM_DATA_LEN 64
+
+static DEFINE_MUTEX(opal_sysparam_mutex);
+static struct kobject *sysparam_kobj;
+static void *param_data_buf;
+
+struct param_attr {
+ struct list_head list;
+ u32 param_id;
+ u32 param_size;
+ struct kobj_attribute kobj_attr;
+};
+
+static int opal_get_sys_param(u32 param_id, u32 length, void *buffer)
+{
+ struct opal_msg msg;
+ int ret, token;
+
+ token = opal_async_get_token_interruptible();
+ if (token < 0) {
+ if (token != -ERESTARTSYS)
+ pr_err("%s: Couldn't get the token, returning\n",
+ __func__);
+ ret = token;
+ goto out;
+ }
+
+ ret = opal_get_param(token, param_id, (u64)buffer, length);
+ if (ret != OPAL_ASYNC_COMPLETION)
+ goto out_token;
+
+ ret = opal_async_wait_response(token, &msg);
+ if (ret) {
+ pr_err("%s: Failed to wait for the async response, %d\n",
+ __func__, ret);
+ goto out_token;
+ }
+
+ ret = msg.params[1];
+
+out_token:
+ opal_async_release_token(token);
+out:
+ return ret;
+}
+
+static int opal_set_sys_param(u32 param_id, u32 length, void *buffer)
+{
+ struct opal_msg msg;
+ int ret, token;
+
+ token = opal_async_get_token_interruptible();
+ if (token < 0) {
+ if (token != -ERESTARTSYS)
+ pr_err("%s: Couldn't get the token, returning\n",
+ __func__);
+ ret = token;
+ goto out;
+ }
+
+ ret = opal_set_param(token, param_id, (u64)buffer, length);
+
+ if (ret != OPAL_ASYNC_COMPLETION)
+ goto out_token;
+
+ ret = opal_async_wait_response(token, &msg);
+ if (ret) {
+ pr_err("%s: Failed to wait for the async response, %d\n",
+ __func__, ret);
+ goto out_token;
+ }
+
+ ret = msg.params[1];
+
+out_token:
+ opal_async_release_token(token);
+out:
+ return ret;
+}
+
+static ssize_t sys_param_show(struct kobject *kobj,
+ struct kobj_attribute *kobj_attr, char *buf)
+{
+ struct param_attr *attr = container_of(kobj_attr, struct param_attr,
+ kobj_attr);
+ int ret;
+
+ mutex_lock(&opal_sysparam_mutex);
+ ret = opal_get_sys_param(attr->param_id, attr->param_size,
+ param_data_buf);
+ if (ret)
+ goto out;
+
+ memcpy(buf, param_data_buf, attr->param_size);
+
+out:
+ mutex_unlock(&opal_sysparam_mutex);
+ return ret ? ret : attr->param_size;
+}
+
+static ssize_t sys_param_store(struct kobject *kobj,
+ struct kobj_attribute *kobj_attr, const char *buf, size_t count)
+{
+ struct param_attr *attr = container_of(kobj_attr, struct param_attr,
+ kobj_attr);
+ int ret;
+
+ mutex_lock(&opal_sysparam_mutex);
+ memcpy(param_data_buf, buf, count);
+ ret = opal_set_sys_param(attr->param_id, attr->param_size,
+ param_data_buf);
+ mutex_unlock(&opal_sysparam_mutex);
+ return ret ? ret : count;
+}
+
+void __init opal_sys_param_init(void)
+{
+ struct device_node *sysparam;
+ struct param_attr *attr;
+ u32 *id, *size;
+ int count, i;
+ u8 *perm;
+
+ if (!opal_kobj) {
+ pr_warn("SYSPARAM: opal kobject is not available\n");
+ goto out;
+ }
+
+ sysparam_kobj = kobject_create_and_add("sysparams", opal_kobj);
+ if (!sysparam_kobj) {
+ pr_err("SYSPARAM: Failed to create sysparam kobject\n");
+ goto out;
+ }
+
+ /* Allocate big enough buffer for any get/set transactions */
+ param_data_buf = kzalloc(MAX_PARAM_DATA_LEN, GFP_KERNEL);
+ if (!param_data_buf) {
+ pr_err("SYSPARAM: Failed to allocate memory for param data "
+ "buf\n");
+ goto out_kobj_put;
+ }
+
+ sysparam = of_find_node_by_path("/ibm,opal/sysparams");
+ if (!sysparam) {
+ pr_err("SYSPARAM: Opal sysparam node not found\n");
+ goto out_param_buf;
+ }
+
+ if (!of_device_is_compatible(sysparam, "ibm,opal-sysparams")) {
+ pr_err("SYSPARAM: Opal sysparam node not compatible\n");
+ goto out_node_put;
+ }
+
+ /* Number of parameters exposed through DT */
+ count = of_property_count_strings(sysparam, "param-name");
+ if (count < 0) {
+ pr_err("SYSPARAM: No string found of property param-name in "
+ "the node %s\n", sysparam->name);
+ goto out_node_put;
+ }
+
+ id = kzalloc(sizeof(*id) * count, GFP_KERNEL);
+ if (!id) {
+ pr_err("SYSPARAM: Failed to allocate memory to read parameter "
+ "id\n");
+ goto out_node_put;
+ }
+
+ size = kzalloc(sizeof(*size) * count, GFP_KERNEL);
+ if (!size) {
+ pr_err("SYSPARAM: Failed to allocate memory to read parameter "
+ "size\n");
+ goto out_free_id;
+ }
+
+ perm = kzalloc(sizeof(*perm) * count, GFP_KERNEL);
+ if (!perm) {
+ pr_err("SYSPARAM: Failed to allocate memory to read supported "
+ "action on the parameter");
+ goto out_free_size;
+ }
+
+ if (of_property_read_u32_array(sysparam, "param-id", id, count)) {
+ pr_err("SYSPARAM: Missing property param-id in the DT\n");
+ goto out_free_perm;
+ }
+
+ if (of_property_read_u32_array(sysparam, "param-len", size, count)) {
+ pr_err("SYSPARAM: Missing propery param-len in the DT\n");
+ goto out_free_perm;
+ }
+
+
+ if (of_property_read_u8_array(sysparam, "param-perm", perm, count)) {
+ pr_err("SYSPARAM: Missing propery param-perm in the DT\n");
+ goto out_free_perm;
+ }
+
+ attr = kzalloc(sizeof(*attr) * count, GFP_KERNEL);
+ if (!attr) {
+ pr_err("SYSPARAM: Failed to allocate memory for parameter "
+ "attributes\n");
+ goto out_free_perm;
+ }
+
+ /* For each of the parameters, populate the parameter attributes */
+ for (i = 0; i < count; i++) {
+ sysfs_attr_init(&attr[i].kobj_attr.attr);
+ attr[i].param_id = id[i];
+ attr[i].param_size = size[i];
+ if (of_property_read_string_index(sysparam, "param-name", i,
+ &attr[i].kobj_attr.attr.name))
+ continue;
+
+ /* If the parameter is read-only or read-write */
+ switch (perm[i] & 3) {
+ case OPAL_SYSPARAM_READ:
+ attr[i].kobj_attr.attr.mode = S_IRUGO;
+ break;
+ case OPAL_SYSPARAM_WRITE:
+ attr[i].kobj_attr.attr.mode = S_IWUGO;
+ break;
+ case OPAL_SYSPARAM_RW:
+ attr[i].kobj_attr.attr.mode = S_IRUGO | S_IWUGO;
+ break;
+ default:
+ break;
+ }
+
+ attr[i].kobj_attr.show = sys_param_show;
+ attr[i].kobj_attr.store = sys_param_store;
+
+ if (sysfs_create_file(sysparam_kobj, &attr[i].kobj_attr.attr)) {
+ pr_err("SYSPARAM: Failed to create sysfs file %s\n",
+ attr[i].kobj_attr.attr.name);
+ goto out_free_attr;
+ }
+ }
+
+ kfree(perm);
+ kfree(size);
+ kfree(id);
+ of_node_put(sysparam);
+ return;
+
+out_free_attr:
+ kfree(attr);
+out_free_perm:
+ kfree(perm);
+out_free_size:
+ kfree(size);
+out_free_id:
+ kfree(id);
+out_node_put:
+ of_node_put(sysparam);
+out_param_buf:
+ kfree(param_data_buf);
+out_kobj_put:
+ kobject_put(sysparam_kobj);
+out:
+ return;
+}