arch/powerpc/platforms/powernv/opal-sysparam.c

   1 /*
   2  * PowerNV system parameter code
   3  *
   4  * Copyright (C) 2013 IBM
   5  *
   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.
  10  *
  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.
  15  *
  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
  19  */
  20
  21 #include <linux/kobject.h>
  22 #include <linux/mutex.h>
  23 #include <linux/slab.h>
  24 #include <linux/of.h>
  25 #include <linux/gfp.h>
  26 #include <linux/stat.h>
  27 #include <asm/opal.h>
  28
  29 #define MAX_PARAM_DATA_LEN      64
  30
  31 static DEFINE_MUTEX(opal_sysparam_mutex);
  32 static struct kobject *sysparam_kobj;
  33 static void *param_data_buf;
  34
  35 struct param_attr {
  36         struct list_head list;
  37         u32 param_id;
  38         u32 param_size;
  39         struct kobj_attribute kobj_attr;
  40 };
  41
  42 static ssize_t opal_get_sys_param(u32 param_id, u32 length, void *buffer)
  43 {
  44         struct opal_msg msg;
  45         ssize_t ret;
  46         int token;
  47
  48         token = opal_async_get_token_interruptible();
  49         if (token < 0) {
  50                 if (token != -ERESTARTSYS)
  51                         pr_err("%s: Couldn't get the token, returning\n",
  52                                         __func__);
  53                 ret = token;
  54                 goto out;
  55         }
  56
  57         ret = opal_get_param(token, param_id, (u64)buffer, length);
  58         if (ret != OPAL_ASYNC_COMPLETION) {
  59                 ret = opal_error_code(ret);
  60                 goto out_token;
  61         }
  62
  63         ret = opal_async_wait_response(token, &msg);
  64         if (ret) {
  65                 pr_err("%s: Failed to wait for the async response, %zd\n",
  66                                 __func__, ret);
  67                 goto out_token;
  68         }
  69
  70         ret = opal_error_code(opal_get_async_rc(msg));
  71
  72 out_token:
  73         opal_async_release_token(token);
  74 out:
  75         return ret;
  76 }
  77
  78 static int opal_set_sys_param(u32 param_id, u32 length, void *buffer)
  79 {
  80         struct opal_msg msg;
  81         int ret, token;
  82
  83         token = opal_async_get_token_interruptible();
  84         if (token < 0) {
  85                 if (token != -ERESTARTSYS)
  86                         pr_err("%s: Couldn't get the token, returning\n",
  87                                         __func__);
  88                 ret = token;
  89                 goto out;
  90         }
  91
  92         ret = opal_set_param(token, param_id, (u64)buffer, length);
  93
  94         if (ret != OPAL_ASYNC_COMPLETION) {
  95                 ret = opal_error_code(ret);
  96                 goto out_token;
  97         }
  98
  99         ret = opal_async_wait_response(token, &msg);
 100         if (ret) {
 101                 pr_err("%s: Failed to wait for the async response, %d\n",
 102                                 __func__, ret);
 103                 goto out_token;
 104         }
 105
 106         ret = opal_error_code(opal_get_async_rc(msg));
 107
 108 out_token:
 109         opal_async_release_token(token);
 110 out:
 111         return ret;
 112 }
 113
 114 static ssize_t sys_param_show(struct kobject *kobj,
 115                 struct kobj_attribute *kobj_attr, char *buf)
 116 {
 117         struct param_attr *attr = container_of(kobj_attr, struct param_attr,
 118                         kobj_attr);
 119         ssize_t ret;
 120
 121         mutex_lock(&opal_sysparam_mutex);
 122         ret = opal_get_sys_param(attr->param_id, attr->param_size,
 123                         param_data_buf);
 124         if (ret)
 125                 goto out;
 126
 127         memcpy(buf, param_data_buf, attr->param_size);
 128
 129         ret = attr->param_size;
 130 out:
 131         mutex_unlock(&opal_sysparam_mutex);
 132         return ret;
 133 }
 134
 135 static ssize_t sys_param_store(struct kobject *kobj,
 136                 struct kobj_attribute *kobj_attr, const char *buf, size_t count)
 137 {
 138         struct param_attr *attr = container_of(kobj_attr, struct param_attr,
 139                         kobj_attr);
 140         ssize_t ret;
 141
 142         /* MAX_PARAM_DATA_LEN is sizeof(param_data_buf) */
 143         if (count > MAX_PARAM_DATA_LEN)
 144                 count = MAX_PARAM_DATA_LEN;
 145
 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,
 149                         param_data_buf);
 150         mutex_unlock(&opal_sysparam_mutex);
 151         if (!ret)
 152                 ret = count;
 153         return ret;
 154 }
 155
 156 void __init opal_sys_param_init(void)
 157 {
 158         struct device_node *sysparam;
 159         struct param_attr *attr;
 160         u32 *id, *size;
 161         int count, i;
 162         u8 *perm;
 163
 164         if (!opal_kobj) {
 165                 pr_warn("SYSPARAM: opal kobject is not available\n");
 166                 goto out;
 167         }
 168
 169         /* Some systems do not use sysparams; this is not an error */
 170         sysparam = of_find_node_by_path("/ibm,opal/sysparams");
 171         if (!sysparam)
 172                 goto out;
 173
 174         if (!of_device_is_compatible(sysparam, "ibm,opal-sysparams")) {
 175                 pr_err("SYSPARAM: Opal sysparam node not compatible\n");
 176                 goto out_node_put;
 177         }
 178
 179         sysparam_kobj = kobject_create_and_add("sysparams", opal_kobj);
 180         if (!sysparam_kobj) {
 181                 pr_err("SYSPARAM: Failed to create sysparam kobject\n");
 182                 goto out_node_put;
 183         }
 184
 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 "
 189                                 "buf\n");
 190                 goto out_kobj_put;
 191         }
 192
 193         /* Number of parameters exposed through DT */
 194         count = of_property_count_strings(sysparam, "param-name");
 195         if (count < 0) {
 196                 pr_err("SYSPARAM: No string found of property param-name in "
 197                                 "the node %s\n", sysparam->name);
 198                 goto out_param_buf;
 199         }
 200
 201         id = kzalloc(sizeof(*id) * count, GFP_KERNEL);
 202         if (!id) {
 203                 pr_err("SYSPARAM: Failed to allocate memory to read parameter "
 204                                 "id\n");
 205                 goto out_param_buf;
 206         }
 207
 208         size = kzalloc(sizeof(*size) * count, GFP_KERNEL);
 209         if (!size) {
 210                 pr_err("SYSPARAM: Failed to allocate memory to read parameter "
 211                                 "size\n");
 212                 goto out_free_id;
 213         }
 214
 215         perm = kzalloc(sizeof(*perm) * count, GFP_KERNEL);
 216         if (!perm) {
 217                 pr_err("SYSPARAM: Failed to allocate memory to read supported "
 218                                 "action on the parameter");
 219                 goto out_free_size;
 220         }
 221
 222         if (of_property_read_u32_array(sysparam, "param-id", id, count)) {
 223                 pr_err("SYSPARAM: Missing property param-id in the DT\n");
 224                 goto out_free_perm;
 225         }
 226
 227         if (of_property_read_u32_array(sysparam, "param-len", size, count)) {
 228                 pr_err("SYSPARAM: Missing property param-len in the DT\n");
 229                 goto out_free_perm;
 230         }
 231
 232
 233         if (of_property_read_u8_array(sysparam, "param-perm", perm, count)) {
 234                 pr_err("SYSPARAM: Missing property param-perm in the DT\n");
 235                 goto out_free_perm;
 236         }
 237
 238         attr = kzalloc(sizeof(*attr) * count, GFP_KERNEL);
 239         if (!attr) {
 240                 pr_err("SYSPARAM: Failed to allocate memory for parameter "
 241                                 "attributes\n");
 242                 goto out_free_perm;
 243         }
 244
 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);
 250                         continue;
 251                 }
 252
 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))
 258                         continue;
 259
 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;
 264                         break;
 265                 case OPAL_SYSPARAM_WRITE:
 266                         attr[i].kobj_attr.attr.mode = S_IWUSR;
 267                         break;
 268                 case OPAL_SYSPARAM_RW:
 269                         attr[i].kobj_attr.attr.mode = S_IRUGO | S_IWUSR;
 270                         break;
 271                 default:
 272                         break;
 273                 }
 274
 275                 attr[i].kobj_attr.show = sys_param_show;
 276                 attr[i].kobj_attr.store = sys_param_store;
 277
 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);
 281                         goto out_free_attr;
 282                 }
 283         }
 284
 285         kfree(perm);
 286         kfree(size);
 287         kfree(id);
 288         of_node_put(sysparam);
 289         return;
 290
 291 out_free_attr:
 292         kfree(attr);
 293 out_free_perm:
 294         kfree(perm);
 295 out_free_size:
 296         kfree(size);
 297 out_free_id:
 298         kfree(id);
 299 out_param_buf:
 300         kfree(param_data_buf);
 301 out_kobj_put:
 302         kobject_put(sysparam_kobj);
 303 out_node_put:
 304         of_node_put(sysparam);
 305 out:
 306         return;
 307 }