kernel/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                 goto out_token;
  60
  61         ret = opal_async_wait_response(token, &msg);
  62         if (ret) {
  63                 pr_err("%s: Failed to wait for the async response, %zd\n",
  64                                 __func__, ret);
  65                 goto out_token;
  66         }
  67
  68         ret = be64_to_cpu(msg.params[1]);
  69
  70 out_token:
  71         opal_async_release_token(token);
  72 out:
  73         return ret;
  74 }
  75
  76 static int opal_set_sys_param(u32 param_id, u32 length, void *buffer)
  77 {
  78         struct opal_msg msg;
  79         int ret, token;
  80
  81         token = opal_async_get_token_interruptible();
  82         if (token < 0) {
  83                 if (token != -ERESTARTSYS)
  84                         pr_err("%s: Couldn't get the token, returning\n",
  85                                         __func__);
  86                 ret = token;
  87                 goto out;
  88         }
  89
  90         ret = opal_set_param(token, param_id, (u64)buffer, length);
  91
  92         if (ret != OPAL_ASYNC_COMPLETION)
  93                 goto out_token;
  94
  95         ret = opal_async_wait_response(token, &msg);
  96         if (ret) {
  97                 pr_err("%s: Failed to wait for the async response, %d\n",
  98                                 __func__, ret);
  99                 goto out_token;
 100         }
 101
 102         ret = be64_to_cpu(msg.params[1]);
 103
 104 out_token:
 105         opal_async_release_token(token);
 106 out:
 107         return ret;
 108 }
 109
 110 static ssize_t sys_param_show(struct kobject *kobj,
 111                 struct kobj_attribute *kobj_attr, char *buf)
 112 {
 113         struct param_attr *attr = container_of(kobj_attr, struct param_attr,
 114                         kobj_attr);
 115         ssize_t ret;
 116
 117         mutex_lock(&opal_sysparam_mutex);
 118         ret = opal_get_sys_param(attr->param_id, attr->param_size,
 119                         param_data_buf);
 120         if (ret)
 121                 goto out;
 122
 123         memcpy(buf, param_data_buf, attr->param_size);
 124
 125         ret = attr->param_size;
 126 out:
 127         mutex_unlock(&opal_sysparam_mutex);
 128         return ret;
 129 }
 130
 131 static ssize_t sys_param_store(struct kobject *kobj,
 132                 struct kobj_attribute *kobj_attr, const char *buf, size_t count)
 133 {
 134         struct param_attr *attr = container_of(kobj_attr, struct param_attr,
 135                         kobj_attr);
 136         ssize_t ret;
 137
 138         /* MAX_PARAM_DATA_LEN is sizeof(param_data_buf) */
 139         if (count > MAX_PARAM_DATA_LEN)
 140                 count = MAX_PARAM_DATA_LEN;
 141
 142         mutex_lock(&opal_sysparam_mutex);
 143         memcpy(param_data_buf, buf, count);
 144         ret = opal_set_sys_param(attr->param_id, attr->param_size,
 145                         param_data_buf);
 146         mutex_unlock(&opal_sysparam_mutex);
 147         if (!ret)
 148                 ret = count;
 149         return ret;
 150 }
 151
 152 void __init opal_sys_param_init(void)
 153 {
 154         struct device_node *sysparam;
 155         struct param_attr *attr;
 156         u32 *id, *size;
 157         int count, i;
 158         u8 *perm;
 159
 160         if (!opal_kobj) {
 161                 pr_warn("SYSPARAM: opal kobject is not available\n");
 162                 goto out;
 163         }
 164
 165         sysparam_kobj = kobject_create_and_add("sysparams", opal_kobj);
 166         if (!sysparam_kobj) {
 167                 pr_err("SYSPARAM: Failed to create sysparam kobject\n");
 168                 goto out;
 169         }
 170
 171         /* Allocate big enough buffer for any get/set transactions */
 172         param_data_buf = kzalloc(MAX_PARAM_DATA_LEN, GFP_KERNEL);
 173         if (!param_data_buf) {
 174                 pr_err("SYSPARAM: Failed to allocate memory for param data "
 175                                 "buf\n");
 176                 goto out_kobj_put;
 177         }
 178
 179         sysparam = of_find_node_by_path("/ibm,opal/sysparams");
 180         if (!sysparam) {
 181                 pr_err("SYSPARAM: Opal sysparam node not found\n");
 182                 goto out_param_buf;
 183         }
 184
 185         if (!of_device_is_compatible(sysparam, "ibm,opal-sysparams")) {
 186                 pr_err("SYSPARAM: Opal sysparam node not compatible\n");
 187                 goto out_node_put;
 188         }
 189
 190         /* Number of parameters exposed through DT */
 191         count = of_property_count_strings(sysparam, "param-name");
 192         if (count < 0) {
 193                 pr_err("SYSPARAM: No string found of property param-name in "
 194                                 "the node %s\n", sysparam->name);
 195                 goto out_node_put;
 196         }
 197
 198         id = kzalloc(sizeof(*id) * count, GFP_KERNEL);
 199         if (!id) {
 200                 pr_err("SYSPARAM: Failed to allocate memory to read parameter "
 201                                 "id\n");
 202                 goto out_node_put;
 203         }
 204
 205         size = kzalloc(sizeof(*size) * count, GFP_KERNEL);
 206         if (!size) {
 207                 pr_err("SYSPARAM: Failed to allocate memory to read parameter "
 208                                 "size\n");
 209                 goto out_free_id;
 210         }
 211
 212         perm = kzalloc(sizeof(*perm) * count, GFP_KERNEL);
 213         if (!perm) {
 214                 pr_err("SYSPARAM: Failed to allocate memory to read supported "
 215                                 "action on the parameter");
 216                 goto out_free_size;
 217         }
 218
 219         if (of_property_read_u32_array(sysparam, "param-id", id, count)) {
 220                 pr_err("SYSPARAM: Missing property param-id in the DT\n");
 221                 goto out_free_perm;
 222         }
 223
 224         if (of_property_read_u32_array(sysparam, "param-len", size, count)) {
 225                 pr_err("SYSPARAM: Missing property param-len in the DT\n");
 226                 goto out_free_perm;
 227         }
 228
 229
 230         if (of_property_read_u8_array(sysparam, "param-perm", perm, count)) {
 231                 pr_err("SYSPARAM: Missing property param-perm in the DT\n");
 232                 goto out_free_perm;
 233         }
 234
 235         attr = kzalloc(sizeof(*attr) * count, GFP_KERNEL);
 236         if (!attr) {
 237                 pr_err("SYSPARAM: Failed to allocate memory for parameter "
 238                                 "attributes\n");
 239                 goto out_free_perm;
 240         }
 241
 242         /* For each of the parameters, populate the parameter attributes */
 243         for (i = 0; i < count; i++) {
 244                 if (size[i] > MAX_PARAM_DATA_LEN) {
 245                         pr_warn("SYSPARAM: Not creating parameter %d as size "
 246                                 "exceeds buffer length\n", i);
 247                         continue;
 248                 }
 249
 250                 sysfs_attr_init(&attr[i].kobj_attr.attr);
 251                 attr[i].param_id = id[i];
 252                 attr[i].param_size = size[i];
 253                 if (of_property_read_string_index(sysparam, "param-name", i,
 254                                 &attr[i].kobj_attr.attr.name))
 255                         continue;
 256
 257                 /* If the parameter is read-only or read-write */
 258                 switch (perm[i] & 3) {
 259                 case OPAL_SYSPARAM_READ:
 260                         attr[i].kobj_attr.attr.mode = S_IRUGO;
 261                         break;
 262                 case OPAL_SYSPARAM_WRITE:
 263                         attr[i].kobj_attr.attr.mode = S_IWUSR;
 264                         break;
 265                 case OPAL_SYSPARAM_RW:
 266                         attr[i].kobj_attr.attr.mode = S_IRUGO | S_IWUSR;
 267                         break;
 268                 default:
 269                         break;
 270                 }
 271
 272                 attr[i].kobj_attr.show = sys_param_show;
 273                 attr[i].kobj_attr.store = sys_param_store;
 274
 275                 if (sysfs_create_file(sysparam_kobj, &attr[i].kobj_attr.attr)) {
 276                         pr_err("SYSPARAM: Failed to create sysfs file %s\n",
 277                                         attr[i].kobj_attr.attr.name);
 278                         goto out_free_attr;
 279                 }
 280         }
 281
 282         kfree(perm);
 283         kfree(size);
 284         kfree(id);
 285         of_node_put(sysparam);
 286         return;
 287
 288 out_free_attr:
 289         kfree(attr);
 290 out_free_perm:
 291         kfree(perm);
 292 out_free_size:
 293         kfree(size);
 294 out_free_id:
 295         kfree(id);
 296 out_node_put:
 297         of_node_put(sysparam);
 298 out_param_buf:
 299         kfree(param_data_buf);
 300 out_kobj_put:
 301         kobject_put(sysparam_kobj);
 302 out:
 303         return;
 304 }