2 * PowerNV system parameter code
4 * Copyright (C) 2013 IBM
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 #include <linux/kobject.h>
22 #include <linux/mutex.h>
23 #include <linux/slab.h>
25 #include <linux/gfp.h>
26 #include <linux/stat.h>
29 #define MAX_PARAM_DATA_LEN 64
31 static DEFINE_MUTEX(opal_sysparam_mutex);
32 static struct kobject *sysparam_kobj;
33 static void *param_data_buf;
36 struct list_head list;
39 struct kobj_attribute kobj_attr;
42 static ssize_t opal_get_sys_param(u32 param_id, u32 length, void *buffer)
48 token = opal_async_get_token_interruptible();
50 if (token != -ERESTARTSYS)
51 pr_err("%s: Couldn't get the token, returning\n",
57 ret = opal_get_param(token, param_id, (u64)buffer, length);
58 if (ret != OPAL_ASYNC_COMPLETION) {
59 ret = opal_error_code(ret);
63 ret = opal_async_wait_response(token, &msg);
65 pr_err("%s: Failed to wait for the async response, %zd\n",
70 ret = opal_error_code(opal_get_async_rc(msg));
73 opal_async_release_token(token);
78 static int opal_set_sys_param(u32 param_id, u32 length, void *buffer)
83 token = opal_async_get_token_interruptible();
85 if (token != -ERESTARTSYS)
86 pr_err("%s: Couldn't get the token, returning\n",
92 ret = opal_set_param(token, param_id, (u64)buffer, length);
94 if (ret != OPAL_ASYNC_COMPLETION) {
95 ret = opal_error_code(ret);
99 ret = opal_async_wait_response(token, &msg);
101 pr_err("%s: Failed to wait for the async response, %d\n",
106 ret = opal_error_code(opal_get_async_rc(msg));
109 opal_async_release_token(token);
114 static ssize_t sys_param_show(struct kobject *kobj,
115 struct kobj_attribute *kobj_attr, char *buf)
117 struct param_attr *attr = container_of(kobj_attr, struct param_attr,
121 mutex_lock(&opal_sysparam_mutex);
122 ret = opal_get_sys_param(attr->param_id, attr->param_size,
127 memcpy(buf, param_data_buf, attr->param_size);
129 ret = attr->param_size;
131 mutex_unlock(&opal_sysparam_mutex);
135 static ssize_t sys_param_store(struct kobject *kobj,
136 struct kobj_attribute *kobj_attr, const char *buf, size_t count)
138 struct param_attr *attr = container_of(kobj_attr, struct param_attr,
142 /* MAX_PARAM_DATA_LEN is sizeof(param_data_buf) */
143 if (count > MAX_PARAM_DATA_LEN)
144 count = MAX_PARAM_DATA_LEN;
146 mutex_lock(&opal_sysparam_mutex);
147 memcpy(param_data_buf, buf, count);
148 ret = opal_set_sys_param(attr->param_id, attr->param_size,
150 mutex_unlock(&opal_sysparam_mutex);
156 void __init opal_sys_param_init(void)
158 struct device_node *sysparam;
159 struct param_attr *attr;
165 pr_warn("SYSPARAM: opal kobject is not available\n");
169 /* Some systems do not use sysparams; this is not an error */
170 sysparam = of_find_node_by_path("/ibm,opal/sysparams");
174 if (!of_device_is_compatible(sysparam, "ibm,opal-sysparams")) {
175 pr_err("SYSPARAM: Opal sysparam node not compatible\n");
179 sysparam_kobj = kobject_create_and_add("sysparams", opal_kobj);
180 if (!sysparam_kobj) {
181 pr_err("SYSPARAM: Failed to create sysparam kobject\n");
185 /* Allocate big enough buffer for any get/set transactions */
186 param_data_buf = kzalloc(MAX_PARAM_DATA_LEN, GFP_KERNEL);
187 if (!param_data_buf) {
188 pr_err("SYSPARAM: Failed to allocate memory for param data "
193 /* Number of parameters exposed through DT */
194 count = of_property_count_strings(sysparam, "param-name");
196 pr_err("SYSPARAM: No string found of property param-name in "
197 "the node %s\n", sysparam->name);
201 id = kzalloc(sizeof(*id) * count, GFP_KERNEL);
203 pr_err("SYSPARAM: Failed to allocate memory to read parameter "
208 size = kzalloc(sizeof(*size) * count, GFP_KERNEL);
210 pr_err("SYSPARAM: Failed to allocate memory to read parameter "
215 perm = kzalloc(sizeof(*perm) * count, GFP_KERNEL);
217 pr_err("SYSPARAM: Failed to allocate memory to read supported "
218 "action on the parameter");
222 if (of_property_read_u32_array(sysparam, "param-id", id, count)) {
223 pr_err("SYSPARAM: Missing property param-id in the DT\n");
227 if (of_property_read_u32_array(sysparam, "param-len", size, count)) {
228 pr_err("SYSPARAM: Missing property param-len in the DT\n");
233 if (of_property_read_u8_array(sysparam, "param-perm", perm, count)) {
234 pr_err("SYSPARAM: Missing property param-perm in the DT\n");
238 attr = kzalloc(sizeof(*attr) * count, GFP_KERNEL);
240 pr_err("SYSPARAM: Failed to allocate memory for parameter "
245 /* For each of the parameters, populate the parameter attributes */
246 for (i = 0; i < count; i++) {
247 if (size[i] > MAX_PARAM_DATA_LEN) {
248 pr_warn("SYSPARAM: Not creating parameter %d as size "
249 "exceeds buffer length\n", i);
253 sysfs_attr_init(&attr[i].kobj_attr.attr);
254 attr[i].param_id = id[i];
255 attr[i].param_size = size[i];
256 if (of_property_read_string_index(sysparam, "param-name", i,
257 &attr[i].kobj_attr.attr.name))
260 /* If the parameter is read-only or read-write */
261 switch (perm[i] & 3) {
262 case OPAL_SYSPARAM_READ:
263 attr[i].kobj_attr.attr.mode = S_IRUGO;
265 case OPAL_SYSPARAM_WRITE:
266 attr[i].kobj_attr.attr.mode = S_IWUSR;
268 case OPAL_SYSPARAM_RW:
269 attr[i].kobj_attr.attr.mode = S_IRUGO | S_IWUSR;
275 attr[i].kobj_attr.show = sys_param_show;
276 attr[i].kobj_attr.store = sys_param_store;
278 if (sysfs_create_file(sysparam_kobj, &attr[i].kobj_attr.attr)) {
279 pr_err("SYSPARAM: Failed to create sysfs file %s\n",
280 attr[i].kobj_attr.attr.name);
288 of_node_put(sysparam);
300 kfree(param_data_buf);
302 kobject_put(sysparam_kobj);
304 of_node_put(sysparam);