1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * PowerNV system parameter code
5 * Copyright (C) 2013 IBM
8 #include <linux/kobject.h>
9 #include <linux/mutex.h>
10 #include <linux/slab.h>
12 #include <linux/gfp.h>
13 #include <linux/stat.h>
16 #define MAX_PARAM_DATA_LEN 64
18 static DEFINE_MUTEX(opal_sysparam_mutex);
19 static struct kobject *sysparam_kobj;
20 static void *param_data_buf;
23 struct list_head list;
26 struct kobj_attribute kobj_attr;
29 static ssize_t opal_get_sys_param(u32 param_id, u32 length, void *buffer)
35 token = opal_async_get_token_interruptible();
37 if (token != -ERESTARTSYS)
38 pr_err("%s: Couldn't get the token, returning\n",
44 ret = opal_get_param(token, param_id, (u64)buffer, length);
45 if (ret != OPAL_ASYNC_COMPLETION) {
46 ret = opal_error_code(ret);
50 ret = opal_async_wait_response(token, &msg);
52 pr_err("%s: Failed to wait for the async response, %zd\n",
57 ret = opal_error_code(opal_get_async_rc(msg));
60 opal_async_release_token(token);
65 static int opal_set_sys_param(u32 param_id, u32 length, void *buffer)
70 token = opal_async_get_token_interruptible();
72 if (token != -ERESTARTSYS)
73 pr_err("%s: Couldn't get the token, returning\n",
79 ret = opal_set_param(token, param_id, (u64)buffer, length);
81 if (ret != OPAL_ASYNC_COMPLETION) {
82 ret = opal_error_code(ret);
86 ret = opal_async_wait_response(token, &msg);
88 pr_err("%s: Failed to wait for the async response, %d\n",
93 ret = opal_error_code(opal_get_async_rc(msg));
96 opal_async_release_token(token);
101 static ssize_t sys_param_show(struct kobject *kobj,
102 struct kobj_attribute *kobj_attr, char *buf)
104 struct param_attr *attr = container_of(kobj_attr, struct param_attr,
108 mutex_lock(&opal_sysparam_mutex);
109 ret = opal_get_sys_param(attr->param_id, attr->param_size,
114 memcpy(buf, param_data_buf, attr->param_size);
116 ret = attr->param_size;
118 mutex_unlock(&opal_sysparam_mutex);
122 static ssize_t sys_param_store(struct kobject *kobj,
123 struct kobj_attribute *kobj_attr, const char *buf, size_t count)
125 struct param_attr *attr = container_of(kobj_attr, struct param_attr,
129 /* MAX_PARAM_DATA_LEN is sizeof(param_data_buf) */
130 if (count > MAX_PARAM_DATA_LEN)
131 count = MAX_PARAM_DATA_LEN;
133 mutex_lock(&opal_sysparam_mutex);
134 memcpy(param_data_buf, buf, count);
135 ret = opal_set_sys_param(attr->param_id, attr->param_size,
137 mutex_unlock(&opal_sysparam_mutex);
143 void __init opal_sys_param_init(void)
145 struct device_node *sysparam;
146 struct param_attr *attr;
152 pr_warn("SYSPARAM: opal kobject is not available\n");
156 /* Some systems do not use sysparams; this is not an error */
157 sysparam = of_find_node_by_path("/ibm,opal/sysparams");
161 if (!of_device_is_compatible(sysparam, "ibm,opal-sysparams")) {
162 pr_err("SYSPARAM: Opal sysparam node not compatible\n");
166 sysparam_kobj = kobject_create_and_add("sysparams", opal_kobj);
167 if (!sysparam_kobj) {
168 pr_err("SYSPARAM: Failed to create sysparam kobject\n");
172 /* Allocate big enough buffer for any get/set transactions */
173 param_data_buf = kzalloc(MAX_PARAM_DATA_LEN, GFP_KERNEL);
174 if (!param_data_buf) {
175 pr_err("SYSPARAM: Failed to allocate memory for param data "
180 /* Number of parameters exposed through DT */
181 count = of_property_count_strings(sysparam, "param-name");
183 pr_err("SYSPARAM: No string found of property param-name in "
184 "the node %pOFn\n", sysparam);
188 id = kcalloc(count, sizeof(*id), GFP_KERNEL);
190 pr_err("SYSPARAM: Failed to allocate memory to read parameter "
195 size = kcalloc(count, sizeof(*size), GFP_KERNEL);
197 pr_err("SYSPARAM: Failed to allocate memory to read parameter "
202 perm = kcalloc(count, sizeof(*perm), GFP_KERNEL);
204 pr_err("SYSPARAM: Failed to allocate memory to read supported "
205 "action on the parameter");
209 if (of_property_read_u32_array(sysparam, "param-id", id, count)) {
210 pr_err("SYSPARAM: Missing property param-id in the DT\n");
214 if (of_property_read_u32_array(sysparam, "param-len", size, count)) {
215 pr_err("SYSPARAM: Missing property param-len in the DT\n");
220 if (of_property_read_u8_array(sysparam, "param-perm", perm, count)) {
221 pr_err("SYSPARAM: Missing property param-perm in the DT\n");
225 attr = kcalloc(count, sizeof(*attr), GFP_KERNEL);
227 pr_err("SYSPARAM: Failed to allocate memory for parameter "
232 /* For each of the parameters, populate the parameter attributes */
233 for (i = 0; i < count; i++) {
234 if (size[i] > MAX_PARAM_DATA_LEN) {
235 pr_warn("SYSPARAM: Not creating parameter %d as size "
236 "exceeds buffer length\n", i);
240 sysfs_attr_init(&attr[i].kobj_attr.attr);
241 attr[i].param_id = id[i];
242 attr[i].param_size = size[i];
243 if (of_property_read_string_index(sysparam, "param-name", i,
244 &attr[i].kobj_attr.attr.name))
247 /* If the parameter is read-only or read-write */
248 switch (perm[i] & 3) {
249 case OPAL_SYSPARAM_READ:
250 attr[i].kobj_attr.attr.mode = 0444;
252 case OPAL_SYSPARAM_WRITE:
253 attr[i].kobj_attr.attr.mode = 0200;
255 case OPAL_SYSPARAM_RW:
256 attr[i].kobj_attr.attr.mode = 0644;
262 attr[i].kobj_attr.show = sys_param_show;
263 attr[i].kobj_attr.store = sys_param_store;
265 if (sysfs_create_file(sysparam_kobj, &attr[i].kobj_attr.attr)) {
266 pr_err("SYSPARAM: Failed to create sysfs file %s\n",
267 attr[i].kobj_attr.attr.name);
275 of_node_put(sysparam);
287 kfree(param_data_buf);
289 kobject_put(sysparam_kobj);
291 of_node_put(sysparam);