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 int opal_get_sys_param(u32 param_id, u32 length, void *buffer)
  43 {
  44         struct opal_msg msg;
  45         int ret, token;
  46
  47         token = opal_async_get_token_interruptible();
  48         if (token < 0) {
  49                 if (token != -ERESTARTSYS)
  50                         pr_err("%s: Couldn't get the token, returning\n",
  51                                         __func__);
  52                 ret = token;
  53                 goto out;
  54         }
  55
  56         ret = opal_get_param(token, param_id, (u64)buffer, length);
  57         if (ret != OPAL_ASYNC_COMPLETION)
  58                 goto out_token;
  59
  60         ret = opal_async_wait_response(token, &msg);
  61         if (ret) {
  62                 pr_err("%s: Failed to wait for the async response, %d\n",
  63                                 __func__, ret);
  64                 goto out_token;
  65         }
  66
  67         ret = be64_to_cpu(msg.params[1]);
  68
  69 out_token:
  70         opal_async_release_token(token);
  71 out:
  72         return ret;
  73 }
  74
  75 static int opal_set_sys_param(u32 param_id, u32 length, void *buffer)
  76 {
  77         struct opal_msg msg;
  78         int ret, token;
  79
  80         token = opal_async_get_token_interruptible();
  81         if (token < 0) {
  82                 if (token != -ERESTARTSYS)
  83                         pr_err("%s: Couldn't get the token, returning\n",
  84                                         __func__);
  85                 ret = token;
  86                 goto out;
  87         }
  88
  89         ret = opal_set_param(token, param_id, (u64)buffer, length);
  90
  91         if (ret != OPAL_ASYNC_COMPLETION)
  92                 goto out_token;
  93
  94         ret = opal_async_wait_response(token, &msg);
  95         if (ret) {
  96                 pr_err("%s: Failed to wait for the async response, %d\n",
  97                                 __func__, ret);
  98                 goto out_token;
  99         }
 100
 101         ret = be64_to_cpu(msg.params[1]);
 102
 103 out_token:
 104         opal_async_release_token(token);
 105 out:
 106         return ret;
 107 }
 108
 109 static ssize_t sys_param_show(struct kobject *kobj,
 110                 struct kobj_attribute *kobj_attr, char *buf)
 111 {
 112         struct param_attr *attr = container_of(kobj_attr, struct param_attr,
 113                         kobj_attr);
 114         int ret;
 115
 116         mutex_lock(&opal_sysparam_mutex);
 117         ret = opal_get_sys_param(attr->param_id, attr->param_size,
 118                         param_data_buf);
 119         if (ret)
 120                 goto out;
 121
 122         memcpy(buf, param_data_buf, attr->param_size);
 123
 124 out:
 125         mutex_unlock(&opal_sysparam_mutex);
 126         return ret ? ret : attr->param_size;
 127 }
 128
 129 static ssize_t sys_param_store(struct kobject *kobj,
 130                 struct kobj_attribute *kobj_attr, const char *buf, size_t count)
 131 {
 132         struct param_attr *attr = container_of(kobj_attr, struct param_attr,
 133                         kobj_attr);
 134         int ret;
 135
 136         mutex_lock(&opal_sysparam_mutex);
 137         memcpy(param_data_buf, buf, count);
 138         ret = opal_set_sys_param(attr->param_id, attr->param_size,
 139                         param_data_buf);
 140         mutex_unlock(&opal_sysparam_mutex);
 141         return ret ? ret : count;
 142 }
 143
 144 void __init opal_sys_param_init(void)
 145 {
 146         struct device_node *sysparam;
 147         struct param_attr *attr;
 148         u32 *id, *size;
 149         int count, i;
 150         u8 *perm;
 151
 152         if (!opal_kobj) {
 153                 pr_warn("SYSPARAM: opal kobject is not available\n");
 154                 goto out;
 155         }
 156
 157         sysparam_kobj = kobject_create_and_add("sysparams", opal_kobj);
 158         if (!sysparam_kobj) {
 159                 pr_err("SYSPARAM: Failed to create sysparam kobject\n");
 160                 goto out;
 161         }
 162
 163         /* Allocate big enough buffer for any get/set transactions */
 164         param_data_buf = kzalloc(MAX_PARAM_DATA_LEN, GFP_KERNEL);
 165         if (!param_data_buf) {
 166                 pr_err("SYSPARAM: Failed to allocate memory for param data "
 167                                 "buf\n");
 168                 goto out_kobj_put;
 169         }
 170
 171         sysparam = of_find_node_by_path("/ibm,opal/sysparams");
 172         if (!sysparam) {
 173                 pr_err("SYSPARAM: Opal sysparam node not found\n");
 174                 goto out_param_buf;
 175         }
 176
 177         if (!of_device_is_compatible(sysparam, "ibm,opal-sysparams")) {
 178                 pr_err("SYSPARAM: Opal sysparam node not compatible\n");
 179                 goto out_node_put;
 180         }
 181
 182         /* Number of parameters exposed through DT */
 183         count = of_property_count_strings(sysparam, "param-name");
 184         if (count < 0) {
 185                 pr_err("SYSPARAM: No string found of property param-name in "
 186                                 "the node %s\n", sysparam->name);
 187                 goto out_node_put;
 188         }
 189
 190         id = kzalloc(sizeof(*id) * count, GFP_KERNEL);
 191         if (!id) {
 192                 pr_err("SYSPARAM: Failed to allocate memory to read parameter "
 193                                 "id\n");
 194                 goto out_node_put;
 195         }
 196
 197         size = kzalloc(sizeof(*size) * count, GFP_KERNEL);
 198         if (!size) {
 199                 pr_err("SYSPARAM: Failed to allocate memory to read parameter "
 200                                 "size\n");
 201                 goto out_free_id;
 202         }
 203
 204         perm = kzalloc(sizeof(*perm) * count, GFP_KERNEL);
 205         if (!perm) {
 206                 pr_err("SYSPARAM: Failed to allocate memory to read supported "
 207                                 "action on the parameter");
 208                 goto out_free_size;
 209         }
 210
 211         if (of_property_read_u32_array(sysparam, "param-id", id, count)) {
 212                 pr_err("SYSPARAM: Missing property param-id in the DT\n");
 213                 goto out_free_perm;
 214         }
 215
 216         if (of_property_read_u32_array(sysparam, "param-len", size, count)) {
 217                 pr_err("SYSPARAM: Missing propery param-len in the DT\n");
 218                 goto out_free_perm;
 219         }
 220
 221
 222         if (of_property_read_u8_array(sysparam, "param-perm", perm, count)) {
 223                 pr_err("SYSPARAM: Missing propery param-perm in the DT\n");
 224                 goto out_free_perm;
 225         }
 226
 227         attr = kzalloc(sizeof(*attr) * count, GFP_KERNEL);
 228         if (!attr) {
 229                 pr_err("SYSPARAM: Failed to allocate memory for parameter "
 230                                 "attributes\n");
 231                 goto out_free_perm;
 232         }
 233
 234         /* For each of the parameters, populate the parameter attributes */
 235         for (i = 0; i < count; i++) {
 236                 sysfs_attr_init(&attr[i].kobj_attr.attr);
 237                 attr[i].param_id = id[i];
 238                 attr[i].param_size = size[i];
 239                 if (of_property_read_string_index(sysparam, "param-name", i,
 240                                 &attr[i].kobj_attr.attr.name))
 241                         continue;
 242
 243                 /* If the parameter is read-only or read-write */
 244                 switch (perm[i] & 3) {
 245                 case OPAL_SYSPARAM_READ:
 246                         attr[i].kobj_attr.attr.mode = S_IRUGO;
 247                         break;
 248                 case OPAL_SYSPARAM_WRITE:
 249                         attr[i].kobj_attr.attr.mode = S_IWUGO;
 250                         break;
 251                 case OPAL_SYSPARAM_RW:
 252                         attr[i].kobj_attr.attr.mode = S_IRUGO | S_IWUGO;
 253                         break;
 254                 default:
 255                         break;
 256                 }
 257
 258                 attr[i].kobj_attr.show = sys_param_show;
 259                 attr[i].kobj_attr.store = sys_param_store;
 260
 261                 if (sysfs_create_file(sysparam_kobj, &attr[i].kobj_attr.attr)) {
 262                         pr_err("SYSPARAM: Failed to create sysfs file %s\n",
 263                                         attr[i].kobj_attr.attr.name);
 264                         goto out_free_attr;
 265                 }
 266         }
 267
 268         kfree(perm);
 269         kfree(size);
 270         kfree(id);
 271         of_node_put(sysparam);
 272         return;
 273
 274 out_free_attr:
 275         kfree(attr);
 276 out_free_perm:
 277         kfree(perm);
 278 out_free_size:
 279         kfree(size);
 280 out_free_id:
 281         kfree(id);
 282 out_node_put:
 283         of_node_put(sysparam);
 284 out_param_buf:
 285         kfree(param_data_buf);
 286 out_kobj_put:
 287         kobject_put(sysparam_kobj);
 288 out:
 289         return;
 290 }