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

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * PowerNV system parameter code
   4  *
   5  * Copyright (C) 2013 IBM
   6  */
   7
   8 #include <linux/kobject.h>
   9 #include <linux/mutex.h>
  10 #include <linux/slab.h>
  11 #include <linux/of.h>
  12 #include <linux/gfp.h>
  13 #include <linux/stat.h>
  14 #include <asm/opal.h>
  15
  16 #define MAX_PARAM_DATA_LEN      64
  17
  18 static DEFINE_MUTEX(opal_sysparam_mutex);
  19 static struct kobject *sysparam_kobj;
  20 static void *param_data_buf;
  21
  22 struct param_attr {
  23         struct list_head list;
  24         u32 param_id;
  25         u32 param_size;
  26         struct kobj_attribute kobj_attr;
  27 };
  28
  29 static ssize_t opal_get_sys_param(u32 param_id, u32 length, void *buffer)
  30 {
  31         struct opal_msg msg;
  32         ssize_t ret;
  33         int token;
  34
  35         token = opal_async_get_token_interruptible();
  36         if (token < 0) {
  37                 if (token != -ERESTARTSYS)
  38                         pr_err("%s: Couldn't get the token, returning\n",
  39                                         __func__);
  40                 ret = token;
  41                 goto out;
  42         }
  43
  44         ret = opal_get_param(token, param_id, (u64)buffer, length);
  45         if (ret != OPAL_ASYNC_COMPLETION) {
  46                 ret = opal_error_code(ret);
  47                 goto out_token;
  48         }
  49
  50         ret = opal_async_wait_response(token, &msg);
  51         if (ret) {
  52                 pr_err("%s: Failed to wait for the async response, %zd\n",
  53                                 __func__, ret);
  54                 goto out_token;
  55         }
  56
  57         ret = opal_error_code(opal_get_async_rc(msg));
  58
  59 out_token:
  60         opal_async_release_token(token);
  61 out:
  62         return ret;
  63 }
  64
  65 static int opal_set_sys_param(u32 param_id, u32 length, void *buffer)
  66 {
  67         struct opal_msg msg;
  68         int ret, token;
  69
  70         token = opal_async_get_token_interruptible();
  71         if (token < 0) {
  72                 if (token != -ERESTARTSYS)
  73                         pr_err("%s: Couldn't get the token, returning\n",
  74                                         __func__);
  75                 ret = token;
  76                 goto out;
  77         }
  78
  79         ret = opal_set_param(token, param_id, (u64)buffer, length);
  80
  81         if (ret != OPAL_ASYNC_COMPLETION) {
  82                 ret = opal_error_code(ret);
  83                 goto out_token;
  84         }
  85
  86         ret = opal_async_wait_response(token, &msg);
  87         if (ret) {
  88                 pr_err("%s: Failed to wait for the async response, %d\n",
  89                                 __func__, ret);
  90                 goto out_token;
  91         }
  92
  93         ret = opal_error_code(opal_get_async_rc(msg));
  94
  95 out_token:
  96         opal_async_release_token(token);
  97 out:
  98         return ret;
  99 }
 100
 101 static ssize_t sys_param_show(struct kobject *kobj,
 102                 struct kobj_attribute *kobj_attr, char *buf)
 103 {
 104         struct param_attr *attr = container_of(kobj_attr, struct param_attr,
 105                         kobj_attr);
 106         ssize_t ret;
 107
 108         mutex_lock(&opal_sysparam_mutex);
 109         ret = opal_get_sys_param(attr->param_id, attr->param_size,
 110                         param_data_buf);
 111         if (ret)
 112                 goto out;
 113
 114         memcpy(buf, param_data_buf, attr->param_size);
 115
 116         ret = attr->param_size;
 117 out:
 118         mutex_unlock(&opal_sysparam_mutex);
 119         return ret;
 120 }
 121
 122 static ssize_t sys_param_store(struct kobject *kobj,
 123                 struct kobj_attribute *kobj_attr, const char *buf, size_t count)
 124 {
 125         struct param_attr *attr = container_of(kobj_attr, struct param_attr,
 126                         kobj_attr);
 127         ssize_t ret;
 128
 129         /* MAX_PARAM_DATA_LEN is sizeof(param_data_buf) */
 130         if (count > MAX_PARAM_DATA_LEN)
 131                 count = MAX_PARAM_DATA_LEN;
 132
 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,
 136                         param_data_buf);
 137         mutex_unlock(&opal_sysparam_mutex);
 138         if (!ret)
 139                 ret = count;
 140         return ret;
 141 }
 142
 143 void __init opal_sys_param_init(void)
 144 {
 145         struct device_node *sysparam;
 146         struct param_attr *attr;
 147         u32 *id, *size;
 148         int count, i;
 149         u8 *perm;
 150
 151         if (!opal_kobj) {
 152                 pr_warn("SYSPARAM: opal kobject is not available\n");
 153                 goto out;
 154         }
 155
 156         /* Some systems do not use sysparams; this is not an error */
 157         sysparam = of_find_node_by_path("/ibm,opal/sysparams");
 158         if (!sysparam)
 159                 goto out;
 160
 161         if (!of_device_is_compatible(sysparam, "ibm,opal-sysparams")) {
 162                 pr_err("SYSPARAM: Opal sysparam node not compatible\n");
 163                 goto out_node_put;
 164         }
 165
 166         sysparam_kobj = kobject_create_and_add("sysparams", opal_kobj);
 167         if (!sysparam_kobj) {
 168                 pr_err("SYSPARAM: Failed to create sysparam kobject\n");
 169                 goto out_node_put;
 170         }
 171
 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 "
 176                                 "buf\n");
 177                 goto out_kobj_put;
 178         }
 179
 180         /* Number of parameters exposed through DT */
 181         count = of_property_count_strings(sysparam, "param-name");
 182         if (count < 0) {
 183                 pr_err("SYSPARAM: No string found of property param-name in "
 184                                 "the node %pOFn\n", sysparam);
 185                 goto out_param_buf;
 186         }
 187
 188         id = kcalloc(count, sizeof(*id), GFP_KERNEL);
 189         if (!id) {
 190                 pr_err("SYSPARAM: Failed to allocate memory to read parameter "
 191                                 "id\n");
 192                 goto out_param_buf;
 193         }
 194
 195         size = kcalloc(count, sizeof(*size), GFP_KERNEL);
 196         if (!size) {
 197                 pr_err("SYSPARAM: Failed to allocate memory to read parameter "
 198                                 "size\n");
 199                 goto out_free_id;
 200         }
 201
 202         perm = kcalloc(count, sizeof(*perm), GFP_KERNEL);
 203         if (!perm) {
 204                 pr_err("SYSPARAM: Failed to allocate memory to read supported "
 205                                 "action on the parameter");
 206                 goto out_free_size;
 207         }
 208
 209         if (of_property_read_u32_array(sysparam, "param-id", id, count)) {
 210                 pr_err("SYSPARAM: Missing property param-id in the DT\n");
 211                 goto out_free_perm;
 212         }
 213
 214         if (of_property_read_u32_array(sysparam, "param-len", size, count)) {
 215                 pr_err("SYSPARAM: Missing property param-len in the DT\n");
 216                 goto out_free_perm;
 217         }
 218
 219
 220         if (of_property_read_u8_array(sysparam, "param-perm", perm, count)) {
 221                 pr_err("SYSPARAM: Missing property param-perm in the DT\n");
 222                 goto out_free_perm;
 223         }
 224
 225         attr = kcalloc(count, sizeof(*attr), GFP_KERNEL);
 226         if (!attr) {
 227                 pr_err("SYSPARAM: Failed to allocate memory for parameter "
 228                                 "attributes\n");
 229                 goto out_free_perm;
 230         }
 231
 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);
 237                         continue;
 238                 }
 239
 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))
 245                         continue;
 246
 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;
 251                         break;
 252                 case OPAL_SYSPARAM_WRITE:
 253                         attr[i].kobj_attr.attr.mode = 0200;
 254                         break;
 255                 case OPAL_SYSPARAM_RW:
 256                         attr[i].kobj_attr.attr.mode = 0644;
 257                         break;
 258                 default:
 259                         break;
 260                 }
 261
 262                 attr[i].kobj_attr.show = sys_param_show;
 263                 attr[i].kobj_attr.store = sys_param_store;
 264
 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);
 268                         goto out_free_attr;
 269                 }
 270         }
 271
 272         kfree(perm);
 273         kfree(size);
 274         kfree(id);
 275         of_node_put(sysparam);
 276         return;
 277
 278 out_free_attr:
 279         kfree(attr);
 280 out_free_perm:
 281         kfree(perm);
 282 out_free_size:
 283         kfree(size);
 284 out_free_id:
 285         kfree(id);
 286 out_param_buf:
 287         kfree(param_data_buf);
 288 out_kobj_put:
 289         kobject_put(sysparam_kobj);
 290 out_node_put:
 291         of_node_put(sysparam);
 292 out:
 293         return;
 294 }