net/rfkill/rfkill.c

   1 /*
   2  * Copyright (C) 2006 - 2007 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
  41 static void rfkill_led_trigger(struct rfkill *rfkill,
  42                                enum rfkill_state state)
  43 {
  44 #ifdef CONFIG_RFKILL_LEDS
  45         struct led_trigger *led = &rfkill->led_trigger;
  46
  47         if (!led->name)
  48                 return;
  49         if (state == RFKILL_STATE_OFF)
  50                 led_trigger_event(led, LED_OFF);
  51         else
  52                 led_trigger_event(led, LED_FULL);
  53 #endif /* CONFIG_RFKILL_LEDS */
  54 }
  55
  56 static int rfkill_toggle_radio(struct rfkill *rfkill,
  57                                 enum rfkill_state state)
  58 {
  59         int retval;
  60
  61         retval = mutex_lock_interruptible(&rfkill->mutex);
  62         if (retval)
  63                 return retval;
  64
  65         if (state != rfkill->state) {
  66                 retval = rfkill->toggle_radio(rfkill->data, state);
  67                 if (!retval) {
  68                         rfkill->state = state;
  69                         rfkill_led_trigger(rfkill, state);
  70                 }
  71         }
  72
  73         mutex_unlock(&rfkill->mutex);
  74         return retval;
  75 }
  76
  77 /**
  78  * rfkill_switch_all - Toggle state of all switches of given type
  79  * @type: type of interfaces to be affeceted
  80  * @state: the new state
  81  *
  82  * This function toggles state of all switches of given type unless
  83  * a specific switch is claimed by userspace in which case it is
  84  * left alone.
  85  */
  86
  87 void rfkill_switch_all(enum rfkill_type type, enum rfkill_state state)
  88 {
  89         struct rfkill *rfkill;
  90
  91         mutex_lock(&rfkill_mutex);
  92
  93         rfkill_states[type] = state;
  94
  95         list_for_each_entry(rfkill, &rfkill_list, node) {
  96                 if (!rfkill->user_claim)
  97                         rfkill_toggle_radio(rfkill, state);
  98         }
  99
 100         mutex_unlock(&rfkill_mutex);
 101 }
 102 EXPORT_SYMBOL(rfkill_switch_all);
 103
 104 static ssize_t rfkill_name_show(struct device *dev,
 105                                 struct device_attribute *attr,
 106                                 char *buf)
 107 {
 108         struct rfkill *rfkill = to_rfkill(dev);
 109
 110         return sprintf(buf, "%s\n", rfkill->name);
 111 }
 112
 113 static ssize_t rfkill_type_show(struct device *dev,
 114                                 struct device_attribute *attr,
 115                                 char *buf)
 116 {
 117         struct rfkill *rfkill = to_rfkill(dev);
 118         const char *type;
 119
 120         switch (rfkill->type) {
 121         case RFKILL_TYPE_WLAN:
 122                 type = "wlan";
 123                 break;
 124         case RFKILL_TYPE_BLUETOOTH:
 125                 type = "bluetooth";
 126                 break;
 127         case RFKILL_TYPE_UWB:
 128                 type = "ultrawideband";
 129                 break;
 130         default:
 131                 BUG();
 132         }
 133
 134         return sprintf(buf, "%s\n", type);
 135 }
 136
 137 static ssize_t rfkill_state_show(struct device *dev,
 138                                  struct device_attribute *attr,
 139                                  char *buf)
 140 {
 141         struct rfkill *rfkill = to_rfkill(dev);
 142
 143         return sprintf(buf, "%d\n", rfkill->state);
 144 }
 145
 146 static ssize_t rfkill_state_store(struct device *dev,
 147                                   struct device_attribute *attr,
 148                                   const char *buf, size_t count)
 149 {
 150         struct rfkill *rfkill = to_rfkill(dev);
 151         unsigned int state = simple_strtoul(buf, NULL, 0);
 152         int error;
 153
 154         if (!capable(CAP_NET_ADMIN))
 155                 return -EPERM;
 156
 157         error = rfkill_toggle_radio(rfkill,
 158                         state ? RFKILL_STATE_ON : RFKILL_STATE_OFF);
 159         if (error)
 160                 return error;
 161
 162         return count;
 163 }
 164
 165 static ssize_t rfkill_claim_show(struct device *dev,
 166                                  struct device_attribute *attr,
 167                                  char *buf)
 168 {
 169         struct rfkill *rfkill = to_rfkill(dev);
 170
 171         return sprintf(buf, "%d", rfkill->user_claim);
 172 }
 173
 174 static ssize_t rfkill_claim_store(struct device *dev,
 175                                   struct device_attribute *attr,
 176                                   const char *buf, size_t count)
 177 {
 178         struct rfkill *rfkill = to_rfkill(dev);
 179         bool claim = !!simple_strtoul(buf, NULL, 0);
 180         int error;
 181
 182         if (!capable(CAP_NET_ADMIN))
 183                 return -EPERM;
 184
 185         /*
 186          * Take the global lock to make sure the kernel is not in
 187          * the middle of rfkill_switch_all
 188          */
 189         error = mutex_lock_interruptible(&rfkill_mutex);
 190         if (error)
 191                 return error;
 192
 193         if (rfkill->user_claim_unsupported) {
 194                 error = -EOPNOTSUPP;
 195                 goto out_unlock;
 196         }
 197         if (rfkill->user_claim != claim) {
 198                 if (!claim)
 199                         rfkill_toggle_radio(rfkill,
 200                                             rfkill_states[rfkill->type]);
 201                 rfkill->user_claim = claim;
 202         }
 203
 204 out_unlock:
 205         mutex_unlock(&rfkill_mutex);
 206
 207         return error ? error : count;
 208 }
 209
 210 static struct device_attribute rfkill_dev_attrs[] = {
 211         __ATTR(name, S_IRUGO, rfkill_name_show, NULL),
 212         __ATTR(type, S_IRUGO, rfkill_type_show, NULL),
 213         __ATTR(state, S_IRUGO|S_IWUSR, rfkill_state_show, rfkill_state_store),
 214         __ATTR(claim, S_IRUGO|S_IWUSR, rfkill_claim_show, rfkill_claim_store),
 215         __ATTR_NULL
 216 };
 217
 218 static void rfkill_release(struct device *dev)
 219 {
 220         struct rfkill *rfkill = to_rfkill(dev);
 221
 222         kfree(rfkill);
 223         module_put(THIS_MODULE);
 224 }
 225
 226 #ifdef CONFIG_PM
 227 static int rfkill_suspend(struct device *dev, pm_message_t state)
 228 {
 229         struct rfkill *rfkill = to_rfkill(dev);
 230
 231         if (dev->power.power_state.event != state.event) {
 232                 if (state.event == PM_EVENT_SUSPEND) {
 233                         mutex_lock(&rfkill->mutex);
 234
 235                         if (rfkill->state == RFKILL_STATE_ON)
 236                                 rfkill->toggle_radio(rfkill->data,
 237                                                      RFKILL_STATE_OFF);
 238
 239                         mutex_unlock(&rfkill->mutex);
 240                 }
 241
 242                 dev->power.power_state = state;
 243         }
 244
 245         return 0;
 246 }
 247
 248 static int rfkill_resume(struct device *dev)
 249 {
 250         struct rfkill *rfkill = to_rfkill(dev);
 251
 252         if (dev->power.power_state.event != PM_EVENT_ON) {
 253                 mutex_lock(&rfkill->mutex);
 254
 255                 if (rfkill->state == RFKILL_STATE_ON)
 256                         rfkill->toggle_radio(rfkill->data, RFKILL_STATE_ON);
 257
 258                 mutex_unlock(&rfkill->mutex);
 259         }
 260
 261         dev->power.power_state = PMSG_ON;
 262         return 0;
 263 }
 264 #else
 265 #define rfkill_suspend NULL
 266 #define rfkill_resume NULL
 267 #endif
 268
 269 static struct class rfkill_class = {
 270         .name           = "rfkill",
 271         .dev_release    = rfkill_release,
 272         .dev_attrs      = rfkill_dev_attrs,
 273         .suspend        = rfkill_suspend,
 274         .resume         = rfkill_resume,
 275 };
 276
 277 static int rfkill_add_switch(struct rfkill *rfkill)
 278 {
 279         int retval;
 280
 281         retval = mutex_lock_interruptible(&rfkill_mutex);
 282         if (retval)
 283                 return retval;
 284
 285         retval = rfkill_toggle_radio(rfkill, rfkill_states[rfkill->type]);
 286         if (retval)
 287                 goto out;
 288
 289         list_add_tail(&rfkill->node, &rfkill_list);
 290
 291  out:
 292         mutex_unlock(&rfkill_mutex);
 293         return retval;
 294 }
 295
 296 static void rfkill_remove_switch(struct rfkill *rfkill)
 297 {
 298         mutex_lock(&rfkill_mutex);
 299         list_del_init(&rfkill->node);
 300         rfkill_toggle_radio(rfkill, RFKILL_STATE_OFF);
 301         mutex_unlock(&rfkill_mutex);
 302 }
 303
 304 /**
 305  * rfkill_allocate - allocate memory for rfkill structure.
 306  * @parent: device that has rf switch on it
 307  * @type: type of the switch (RFKILL_TYPE_*)
 308  *
 309  * This function should be called by the network driver when it needs
 310  * rfkill structure. Once the structure is allocated the driver shoud
 311  * finish its initialization by setting name, private data, enable_radio
 312  * and disable_radio methods and then register it with rfkill_register().
 313  * NOTE: If registration fails the structure shoudl be freed by calling
 314  * rfkill_free() otherwise rfkill_unregister() should be used.
 315  */
 316 struct rfkill *rfkill_allocate(struct device *parent, enum rfkill_type type)
 317 {
 318         struct rfkill *rfkill;
 319         struct device *dev;
 320
 321         rfkill = kzalloc(sizeof(struct rfkill), GFP_KERNEL);
 322         if (!rfkill)
 323                 return NULL;
 324
 325         mutex_init(&rfkill->mutex);
 326         INIT_LIST_HEAD(&rfkill->node);
 327         rfkill->type = type;
 328
 329         dev = &rfkill->dev;
 330         dev->class = &rfkill_class;
 331         dev->parent = parent;
 332         device_initialize(dev);
 333
 334         __module_get(THIS_MODULE);
 335
 336         return rfkill;
 337 }
 338 EXPORT_SYMBOL(rfkill_allocate);
 339
 340 /**
 341  * rfkill_free - Mark rfkill structure for deletion
 342  * @rfkill: rfkill structure to be destroyed
 343  *
 344  * Decrements reference count of rfkill structure so it is destoryed.
 345  * Note that rfkill_free() should _not_ be called after rfkill_unregister().
 346  */
 347 void rfkill_free(struct rfkill *rfkill)
 348 {
 349         if (rfkill)
 350                 put_device(&rfkill->dev);
 351 }
 352 EXPORT_SYMBOL(rfkill_free);
 353
 354 static void rfkill_led_trigger_register(struct rfkill *rfkill)
 355 {
 356 #ifdef CONFIG_RFKILL_LEDS
 357         int error;
 358
 359         rfkill->led_trigger.name = rfkill->dev.bus_id;
 360         error = led_trigger_register(&rfkill->led_trigger);
 361         if (error)
 362                 rfkill->led_trigger.name = NULL;
 363 #endif /* CONFIG_RFKILL_LEDS */
 364 }
 365
 366 static void rfkill_led_trigger_unregister(struct rfkill *rfkill)
 367 {
 368 #ifdef CONFIG_RFKILL_LEDS
 369         if (rfkill->led_trigger.name)
 370                 led_trigger_unregister(&rfkill->led_trigger);
 371 #endif
 372 }
 373
 374 /**
 375  * rfkill_register - Register a rfkill structure.
 376  * @rfkill: rfkill structure to be registered
 377  *
 378  * This function should be called by the network driver when the rfkill
 379  * structure needs to be registered. Immediately from registration the
 380  * switch driver should be able to service calls to toggle_radio.
 381  */
 382 int rfkill_register(struct rfkill *rfkill)
 383 {
 384         static atomic_t rfkill_no = ATOMIC_INIT(0);
 385         struct device *dev = &rfkill->dev;
 386         int error;
 387
 388         if (!rfkill->toggle_radio)
 389                 return -EINVAL;
 390
 391         error = rfkill_add_switch(rfkill);
 392         if (error)
 393                 return error;
 394
 395         snprintf(dev->bus_id, sizeof(dev->bus_id),
 396                  "rfkill%ld", (long)atomic_inc_return(&rfkill_no) - 1);
 397
 398         error = device_add(dev);
 399         if (error) {
 400                 rfkill_remove_switch(rfkill);
 401                 return error;
 402         }
 403         rfkill_led_trigger_register(rfkill);
 404
 405         return 0;
 406 }
 407 EXPORT_SYMBOL(rfkill_register);
 408
 409 /**
 410  * rfkill_unregister - Uegister a rfkill structure.
 411  * @rfkill: rfkill structure to be unregistered
 412  *
 413  * This function should be called by the network driver during device
 414  * teardown to destroy rfkill structure. Note that rfkill_free() should
 415  * _not_ be called after rfkill_unregister().
 416  */
 417 void rfkill_unregister(struct rfkill *rfkill)
 418 {
 419         rfkill_led_trigger_unregister(rfkill);
 420         device_del(&rfkill->dev);
 421         rfkill_remove_switch(rfkill);
 422         put_device(&rfkill->dev);
 423 }
 424 EXPORT_SYMBOL(rfkill_unregister);
 425
 426 /*
 427  * Rfkill module initialization/deinitialization.
 428  */
 429 static int __init rfkill_init(void)
 430 {
 431         int error;
 432         int i;
 433
 434         for (i = 0; i < ARRAY_SIZE(rfkill_states); i++)
 435                 rfkill_states[i] = RFKILL_STATE_ON;
 436
 437         error = class_register(&rfkill_class);
 438         if (error) {
 439                 printk(KERN_ERR "rfkill: unable to register rfkill class\n");
 440                 return error;
 441         }
 442
 443         return 0;
 444 }
 445
 446 static void __exit rfkill_exit(void)
 447 {
 448         class_unregister(&rfkill_class);
 449 }
 450
 451 module_init(rfkill_init);
 452 module_exit(rfkill_exit);