net/rfkill/rfkill.c

   1 /*
   2  * Copyright (C) 2006 Ivo van Doorn
   3  * Copyright (C) 2007 Dmitry Torokhov
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the
  17  * Free Software Foundation, Inc.,
  18  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  */
  20
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23 #include <linux/init.h>
  24 #include <linux/workqueue.h>
  25 #include <linux/capability.h>
  26 #include <linux/list.h>
  27 #include <linux/mutex.h>
  28 #include <linux/rfkill.h>
  29
  30 MODULE_AUTHOR("Ivo van Doorn <IvDoorn@gmail.com>");
  31 MODULE_VERSION("1.0");
  32 MODULE_DESCRIPTION("RF switch support");
  33 MODULE_LICENSE("GPL");
  34
  35 static LIST_HEAD(rfkill_list);  /* list of registered rf switches */
  36 static DEFINE_MUTEX(rfkill_mutex);
  37
  38 static enum rfkill_state rfkill_states[RFKILL_TYPE_MAX];
  39
  40 static int rfkill_toggle_radio(struct rfkill *rfkill,
  41                                 enum rfkill_state state)
  42 {
  43         int retval;
  44
  45         retval = mutex_lock_interruptible(&rfkill->mutex);
  46         if (retval)
  47                 return retval;
  48
  49         if (state != rfkill->state) {
  50                 retval = rfkill->toggle_radio(rfkill->data, state);
  51                 if (!retval)
  52                         rfkill->state = state;
  53         }
  54
  55         mutex_unlock(&rfkill->mutex);
  56         return retval;
  57 }
  58
  59 /**
  60  * rfkill_switch_all - Toggle state of all switches of given type
  61  * @type: type of interfaces to be affeceted
  62  * @state: the new state
  63  *
  64  * This function toggles state of all switches of given type unless
  65  * a specific switch is claimed by userspace in which case it is
  66  * left alone.
  67  */
  68
  69 void rfkill_switch_all(enum rfkill_type type, enum rfkill_state state)
  70 {
  71         struct rfkill *rfkill;
  72
  73         mutex_lock(&rfkill_mutex);
  74
  75         rfkill_states[type] = state;
  76
  77         list_for_each_entry(rfkill, &rfkill_list, node) {
  78                 if (!rfkill->user_claim)
  79                         rfkill_toggle_radio(rfkill, state);
  80         }
  81
  82         mutex_unlock(&rfkill_mutex);
  83 }
  84 EXPORT_SYMBOL(rfkill_switch_all);
  85
  86 static ssize_t rfkill_name_show(struct device *dev,
  87                                 struct device_attribute *attr,
  88                                 char *buf)
  89 {
  90         struct rfkill *rfkill = to_rfkill(dev);
  91
  92         return sprintf(buf, "%s\n", rfkill->name);
  93 }
  94
  95 static ssize_t rfkill_type_show(struct device *dev,
  96                                 struct device_attribute *attr,
  97                                 char *buf)
  98 {
  99         struct rfkill *rfkill = to_rfkill(dev);
 100         const char *type;
 101
 102         switch (rfkill->type) {
 103         case RFKILL_TYPE_WLAN:
 104                 type = "wlan";
 105                 break;
 106         case RFKILL_TYPE_BLUETOOTH:
 107                 type = "bluetooth";
 108                 break;
 109         case RFKILL_TYPE_IRDA:
 110                 type = "irda";
 111                 break;
 112         default:
 113                 BUG();
 114         }
 115
 116         return sprintf(buf, "%s\n", type);
 117 }
 118
 119 static ssize_t rfkill_state_show(struct device *dev,
 120                                  struct device_attribute *attr,
 121                                  char *buf)
 122 {
 123         struct rfkill *rfkill = to_rfkill(dev);
 124
 125         return sprintf(buf, "%d\n", rfkill->state);
 126 }
 127
 128 static ssize_t rfkill_state_store(struct device *dev,
 129                                   struct device_attribute *attr,
 130                                   const char *buf, size_t count)
 131 {
 132         struct rfkill *rfkill = to_rfkill(dev);
 133         unsigned int state = simple_strtoul(buf, NULL, 0);
 134         int error;
 135
 136         if (!capable(CAP_NET_ADMIN))
 137                 return -EPERM;
 138
 139         error = rfkill_toggle_radio(rfkill,
 140                         state ? RFKILL_STATE_ON : RFKILL_STATE_OFF);
 141         if (error)
 142                 return error;
 143
 144         return count;
 145 }
 146
 147 static ssize_t rfkill_claim_show(struct device *dev,
 148                                  struct device_attribute *attr,
 149                                  char *buf)
 150 {
 151         struct rfkill *rfkill = to_rfkill(dev);
 152
 153         return sprintf(buf, "%d", rfkill->user_claim);
 154 }
 155
 156 static ssize_t rfkill_claim_store(struct device *dev,
 157                                   struct device_attribute *attr,
 158                                   const char *buf, size_t count)
 159 {
 160         struct rfkill *rfkill = to_rfkill(dev);
 161         bool claim = !!simple_strtoul(buf, NULL, 0);
 162         int error;
 163
 164         if (!capable(CAP_NET_ADMIN))
 165                 return -EPERM;
 166
 167         /*
 168          * Take the global lock to make sure the kernel is not in
 169          * the middle of rfkill_switch_all
 170          */
 171         error = mutex_lock_interruptible(&rfkill_mutex);
 172         if (error)
 173                 return error;
 174
 175         if (rfkill->user_claim != claim) {
 176                 if (!claim)
 177                         rfkill_toggle_radio(rfkill,
 178                                             rfkill_states[rfkill->type]);
 179                 rfkill->user_claim = claim;
 180         }
 181
 182         mutex_unlock(&rfkill_mutex);
 183
 184         return count;
 185 }
 186
 187 static struct device_attribute rfkill_dev_attrs[] = {
 188         __ATTR(name, S_IRUGO, rfkill_name_show, NULL),
 189         __ATTR(type, S_IRUGO, rfkill_type_show, NULL),
 190         __ATTR(state, S_IRUGO, rfkill_state_show, rfkill_state_store),
 191         __ATTR(claim, S_IRUGO|S_IWUSR, rfkill_claim_show, rfkill_claim_store),
 192         __ATTR_NULL
 193 };
 194
 195 static void rfkill_release(struct device *dev)
 196 {
 197         struct rfkill *rfkill = to_rfkill(dev);
 198
 199         kfree(rfkill);
 200         module_put(THIS_MODULE);
 201 }
 202
 203 #ifdef CONFIG_PM
 204 static int rfkill_suspend(struct device *dev, pm_message_t state)
 205 {
 206         struct rfkill *rfkill = to_rfkill(dev);
 207
 208         if (dev->power.power_state.event != state.event) {
 209                 if (state.event == PM_EVENT_SUSPEND) {
 210                         mutex_lock(&rfkill->mutex);
 211
 212                         if (rfkill->state == RFKILL_STATE_ON)
 213                                 rfkill->toggle_radio(rfkill->data,
 214                                                      RFKILL_STATE_OFF);
 215
 216                         mutex_unlock(&rfkill->mutex);
 217                 }
 218
 219                 dev->power.power_state = state;
 220         }
 221
 222         return 0;
 223 }
 224
 225 static int rfkill_resume(struct device *dev)
 226 {
 227         struct rfkill *rfkill = to_rfkill(dev);
 228
 229         if (dev->power.power_state.event != PM_EVENT_ON) {
 230                 mutex_lock(&rfkill->mutex);
 231
 232                 if (rfkill->state == RFKILL_STATE_ON)
 233                         rfkill->toggle_radio(rfkill->data, RFKILL_STATE_ON);
 234
 235                 mutex_unlock(&rfkill->mutex);
 236         }
 237
 238         dev->power.power_state = PMSG_ON;
 239         return 0;
 240 }
 241 #else
 242 #define rfkill_suspend NULL
 243 #define rfkill_resume NULL
 244 #endif
 245
 246 static struct class rfkill_class = {
 247         .name           = "rfkill",
 248         .dev_release    = rfkill_release,
 249         .dev_attrs      = rfkill_dev_attrs,
 250         .suspend        = rfkill_suspend,
 251         .resume         = rfkill_resume,
 252 };
 253
 254 static int rfkill_add_switch(struct rfkill *rfkill)
 255 {
 256         int retval;
 257
 258         retval = mutex_lock_interruptible(&rfkill_mutex);
 259         if (retval)
 260                 return retval;
 261
 262         retval = rfkill_toggle_radio(rfkill, rfkill_states[rfkill->type]);
 263         if (retval)
 264                 goto out;
 265
 266         list_add_tail(&rfkill->node, &rfkill_list);
 267
 268  out:
 269         mutex_unlock(&rfkill_mutex);
 270         return retval;
 271 }
 272
 273 static void rfkill_remove_switch(struct rfkill *rfkill)
 274 {
 275         mutex_lock(&rfkill_mutex);
 276         list_del_init(&rfkill->node);
 277         rfkill_toggle_radio(rfkill, RFKILL_STATE_OFF);
 278         mutex_unlock(&rfkill_mutex);
 279 }
 280
 281 /**
 282  * rfkill_allocate - allocate memory for rfkill structure.
 283  * @parent: device that has rf switch on it
 284  * @type: type of the switch (wlan, bluetooth, irda)
 285  *
 286  * This function should be called by the network driver when it needs
 287  * rfkill structure. Once the structure is allocated the driver shoud
 288  * finish its initialization by setting name, private data, enable_radio
 289  * and disable_radio methods and then register it with rfkill_register().
 290  * NOTE: If registration fails the structure shoudl be freed by calling
 291  * rfkill_free() otherwise rfkill_unregister() should be used.
 292  */
 293 struct rfkill *rfkill_allocate(struct device *parent, enum rfkill_type type)
 294 {
 295         struct rfkill *rfkill;
 296         struct device *dev;
 297
 298         rfkill = kzalloc(sizeof(struct rfkill), GFP_KERNEL);
 299         if (!rfkill)
 300                 return NULL;
 301
 302         mutex_init(&rfkill->mutex);
 303         INIT_LIST_HEAD(&rfkill->node);
 304         rfkill->type = type;
 305
 306         dev = &rfkill->dev;
 307         dev->class = &rfkill_class;
 308         dev->parent = parent;
 309         device_initialize(dev);
 310
 311         __module_get(THIS_MODULE);
 312
 313         return rfkill;
 314 }
 315 EXPORT_SYMBOL(rfkill_allocate);
 316
 317 /**
 318  * rfkill_free - Mark rfkill structure for deletion
 319  * @rfkill: rfkill structure to be destroyed
 320  *
 321  * Decrements reference count of rfkill structure so it is destoryed.
 322  * Note that rfkill_free() should _not_ be called after rfkill_unregister().
 323  */
 324 void rfkill_free(struct rfkill *rfkill)
 325 {
 326         if (rfkill)
 327                 put_device(&rfkill->dev);
 328 }
 329 EXPORT_SYMBOL(rfkill_free);
 330
 331 /**
 332  * rfkill_register - Register a rfkill structure.
 333  * @rfkill: rfkill structure to be registered
 334  *
 335  * This function should be called by the network driver when the rfkill
 336  * structure needs to be registered. Immediately from registration the
 337  * switch driver should be able to service calls to toggle_radio.
 338  */
 339 int rfkill_register(struct rfkill *rfkill)
 340 {
 341         static atomic_t rfkill_no = ATOMIC_INIT(0);
 342         struct device *dev = &rfkill->dev;
 343         int error;
 344
 345         if (!rfkill->toggle_radio)
 346                 return -EINVAL;
 347
 348         error = rfkill_add_switch(rfkill);
 349         if (error)
 350                 return error;
 351
 352         snprintf(dev->bus_id, sizeof(dev->bus_id),
 353                  "rfkill%ld", (long)atomic_inc_return(&rfkill_no) - 1);
 354
 355         error = device_add(dev);
 356         if (error) {
 357                 rfkill_remove_switch(rfkill);
 358                 return error;
 359         }
 360
 361         return 0;
 362 }
 363 EXPORT_SYMBOL(rfkill_register);
 364
 365 /**
 366  * rfkill_unregister - Uegister a rfkill structure.
 367  * @rfkill: rfkill structure to be unregistered
 368  *
 369  * This function should be called by the network driver during device
 370  * teardown to destroy rfkill structure. Note that rfkill_free() should
 371  * _not_ be called after rfkill_unregister().
 372  */
 373 void rfkill_unregister(struct rfkill *rfkill)
 374 {
 375         device_del(&rfkill->dev);
 376         rfkill_remove_switch(rfkill);
 377         put_device(&rfkill->dev);
 378 }
 379 EXPORT_SYMBOL(rfkill_unregister);
 380
 381 /*
 382  * Rfkill module initialization/deinitialization.
 383  */
 384 static int __init rfkill_init(void)
 385 {
 386         int error;
 387         int i;
 388
 389         for (i = 0; i < ARRAY_SIZE(rfkill_states); i++)
 390                 rfkill_states[i] = RFKILL_STATE_ON;
 391
 392         error = class_register(&rfkill_class);
 393         if (error) {
 394                 printk(KERN_ERR "rfkill: unable to register rfkill class\n");
 395                 return error;
 396         }
 397
 398         return 0;
 399 }
 400
 401 static void __exit rfkill_exit(void)
 402 {
 403         class_unregister(&rfkill_class);
 404 }
 405
 406 module_init(rfkill_init);
 407 module_exit(rfkill_exit);