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 /* Get declaration of rfkill_switch_all() to shut up sparse. */
  31 #include "rfkill-input.h"
  32
  33
  34 MODULE_AUTHOR("Ivo van Doorn <IvDoorn@gmail.com>");
  35 MODULE_VERSION("1.0");
  36 MODULE_DESCRIPTION("RF switch support");
  37 MODULE_LICENSE("GPL");
  38
  39 static LIST_HEAD(rfkill_list);  /* list of registered rf switches */
  40 static DEFINE_MUTEX(rfkill_mutex);
  41
  42 static unsigned int rfkill_default_state = RFKILL_STATE_ON;
  43 module_param_named(default_state, rfkill_default_state, uint, 0444);
  44 MODULE_PARM_DESC(default_state,
  45                  "Default initial state for all radio types, 0 = radio off");
  46
  47 static enum rfkill_state rfkill_states[RFKILL_TYPE_MAX];
  48
  49 static BLOCKING_NOTIFIER_HEAD(rfkill_notifier_list);
  50
  51
  52 /**
  53  * register_rfkill_notifier - Add notifier to rfkill notifier chain
  54  * @nb: pointer to the new entry to add to the chain
  55  *
  56  * See blocking_notifier_chain_register() for return value and further
  57  * observations.
  58  *
  59  * Adds a notifier to the rfkill notifier chain.  The chain will be
  60  * called with a pointer to the relevant rfkill structure as a parameter,
  61  * refer to include/linux/rfkill.h for the possible events.
  62  *
  63  * Notifiers added to this chain are to always return NOTIFY_DONE.  This
  64  * chain is a blocking notifier chain: notifiers can sleep.
  65  *
  66  * Calls to this chain may have been done through a workqueue.  One must
  67  * assume unordered asynchronous behaviour, there is no way to know if
  68  * actions related to the event that generated the notification have been
  69  * carried out already.
  70  */
  71 int register_rfkill_notifier(struct notifier_block *nb)
  72 {
  73         return blocking_notifier_chain_register(&rfkill_notifier_list, nb);
  74 }
  75 EXPORT_SYMBOL_GPL(register_rfkill_notifier);
  76
  77 /**
  78  * unregister_rfkill_notifier - remove notifier from rfkill notifier chain
  79  * @nb: pointer to the entry to remove from the chain
  80  *
  81  * See blocking_notifier_chain_unregister() for return value and further
  82  * observations.
  83  *
  84  * Removes a notifier from the rfkill notifier chain.
  85  */
  86 int unregister_rfkill_notifier(struct notifier_block *nb)
  87 {
  88         return blocking_notifier_chain_unregister(&rfkill_notifier_list, nb);
  89 }
  90 EXPORT_SYMBOL_GPL(unregister_rfkill_notifier);
  91
  92
  93 static void rfkill_led_trigger(struct rfkill *rfkill,
  94                                enum rfkill_state state)
  95 {
  96 #ifdef CONFIG_RFKILL_LEDS
  97         struct led_trigger *led = &rfkill->led_trigger;
  98
  99         if (!led->name)
 100                 return;
 101         if (state == RFKILL_STATE_OFF)
 102                 led_trigger_event(led, LED_OFF);
 103         else
 104                 led_trigger_event(led, LED_FULL);
 105 #endif /* CONFIG_RFKILL_LEDS */
 106 }
 107
 108 static void notify_rfkill_state_change(struct rfkill *rfkill)
 109 {
 110         blocking_notifier_call_chain(&rfkill_notifier_list,
 111                         RFKILL_STATE_CHANGED,
 112                         rfkill);
 113 }
 114
 115 static void update_rfkill_state(struct rfkill *rfkill)
 116 {
 117         enum rfkill_state newstate, oldstate;
 118
 119         if (rfkill->get_state) {
 120                 mutex_lock(&rfkill->mutex);
 121                 if (!rfkill->get_state(rfkill->data, &newstate)) {
 122                         oldstate = rfkill->state;
 123                         rfkill->state = newstate;
 124                         if (oldstate != newstate)
 125                                 notify_rfkill_state_change(rfkill);
 126                 }
 127                 mutex_unlock(&rfkill->mutex);
 128         }
 129 }
 130
 131 static int rfkill_toggle_radio(struct rfkill *rfkill,
 132                                 enum rfkill_state state,
 133                                 int force)
 134 {
 135         int retval = 0;
 136         enum rfkill_state oldstate, newstate;
 137
 138         oldstate = rfkill->state;
 139
 140         if (rfkill->get_state && !force &&
 141             !rfkill->get_state(rfkill->data, &newstate))
 142                 rfkill->state = newstate;
 143
 144         if (force || state != rfkill->state) {
 145                 retval = rfkill->toggle_radio(rfkill->data, state);
 146                 if (!retval)
 147                         rfkill->state = state;
 148         }
 149
 150         if (force || rfkill->state != oldstate) {
 151                 rfkill_led_trigger(rfkill, rfkill->state);
 152                 notify_rfkill_state_change(rfkill);
 153         }
 154
 155         return retval;
 156 }
 157
 158 /**
 159  * rfkill_switch_all - Toggle state of all switches of given type
 160  * @type: type of interfaces to be affeceted
 161  * @state: the new state
 162  *
 163  * This function toggles state of all switches of given type unless
 164  * a specific switch is claimed by userspace in which case it is
 165  * left alone.
 166  */
 167 void rfkill_switch_all(enum rfkill_type type, enum rfkill_state state)
 168 {
 169         struct rfkill *rfkill;
 170
 171         mutex_lock(&rfkill_mutex);
 172
 173         rfkill_states[type] = state;
 174
 175         list_for_each_entry(rfkill, &rfkill_list, node) {
 176                 if ((!rfkill->user_claim) && (rfkill->type == type))
 177                         rfkill_toggle_radio(rfkill, state, 0);
 178         }
 179
 180         mutex_unlock(&rfkill_mutex);
 181 }
 182 EXPORT_SYMBOL(rfkill_switch_all);
 183
 184 /**
 185  * rfkill_force_state - Force the internal rfkill radio state
 186  * @rfkill: pointer to the rfkill class to modify.
 187  * @state: the current radio state the class should be forced to.
 188  *
 189  * This function updates the internal state of the radio cached
 190  * by the rfkill class.  It should be used when the driver gets
 191  * a notification by the firmware/hardware of the current *real*
 192  * state of the radio rfkill switch.
 193  *
 194  * It may not be called from an atomic context.
 195  */
 196 int rfkill_force_state(struct rfkill *rfkill, enum rfkill_state state)
 197 {
 198         enum rfkill_state oldstate;
 199
 200         if (state != RFKILL_STATE_OFF &&
 201             state != RFKILL_STATE_ON)
 202                 return -EINVAL;
 203
 204         mutex_lock(&rfkill->mutex);
 205
 206         oldstate = rfkill->state;
 207         rfkill->state = state;
 208
 209         if (state != oldstate)
 210                 notify_rfkill_state_change(rfkill);
 211
 212         mutex_unlock(&rfkill->mutex);
 213
 214         return 0;
 215 }
 216 EXPORT_SYMBOL(rfkill_force_state);
 217
 218 static ssize_t rfkill_name_show(struct device *dev,
 219                                 struct device_attribute *attr,
 220                                 char *buf)
 221 {
 222         struct rfkill *rfkill = to_rfkill(dev);
 223
 224         return sprintf(buf, "%s\n", rfkill->name);
 225 }
 226
 227 static const char *rfkill_get_type_str(enum rfkill_type type)
 228 {
 229         switch (type) {
 230         case RFKILL_TYPE_WLAN:
 231                 return "wlan";
 232         case RFKILL_TYPE_BLUETOOTH:
 233                 return "bluetooth";
 234         case RFKILL_TYPE_UWB:
 235                 return "ultrawideband";
 236         case RFKILL_TYPE_WIMAX:
 237                 return "wimax";
 238         case RFKILL_TYPE_WWAN:
 239                 return "wwan";
 240         default:
 241                 BUG();
 242         }
 243 }
 244
 245 static ssize_t rfkill_type_show(struct device *dev,
 246                                 struct device_attribute *attr,
 247                                 char *buf)
 248 {
 249         struct rfkill *rfkill = to_rfkill(dev);
 250
 251         return sprintf(buf, "%s\n", rfkill_get_type_str(rfkill->type));
 252 }
 253
 254 static ssize_t rfkill_state_show(struct device *dev,
 255                                  struct device_attribute *attr,
 256                                  char *buf)
 257 {
 258         struct rfkill *rfkill = to_rfkill(dev);
 259
 260         update_rfkill_state(rfkill);
 261         return sprintf(buf, "%d\n", rfkill->state);
 262 }
 263
 264 static ssize_t rfkill_state_store(struct device *dev,
 265                                   struct device_attribute *attr,
 266                                   const char *buf, size_t count)
 267 {
 268         struct rfkill *rfkill = to_rfkill(dev);
 269         unsigned int state = simple_strtoul(buf, NULL, 0);
 270         int error;
 271
 272         if (!capable(CAP_NET_ADMIN))
 273                 return -EPERM;
 274
 275         if (mutex_lock_interruptible(&rfkill->mutex))
 276                 return -ERESTARTSYS;
 277         error = rfkill_toggle_radio(rfkill,
 278                         state ? RFKILL_STATE_ON : RFKILL_STATE_OFF,
 279                         0);
 280         mutex_unlock(&rfkill->mutex);
 281
 282         return error ? error : count;
 283 }
 284
 285 static ssize_t rfkill_claim_show(struct device *dev,
 286                                  struct device_attribute *attr,
 287                                  char *buf)
 288 {
 289         struct rfkill *rfkill = to_rfkill(dev);
 290
 291         return sprintf(buf, "%d", rfkill->user_claim);
 292 }
 293
 294 static ssize_t rfkill_claim_store(struct device *dev,
 295                                   struct device_attribute *attr,
 296                                   const char *buf, size_t count)
 297 {
 298         struct rfkill *rfkill = to_rfkill(dev);
 299         bool claim = !!simple_strtoul(buf, NULL, 0);
 300         int error;
 301
 302         if (!capable(CAP_NET_ADMIN))
 303                 return -EPERM;
 304
 305         /*
 306          * Take the global lock to make sure the kernel is not in
 307          * the middle of rfkill_switch_all
 308          */
 309         error = mutex_lock_interruptible(&rfkill_mutex);
 310         if (error)
 311                 return error;
 312
 313         if (rfkill->user_claim_unsupported) {
 314                 error = -EOPNOTSUPP;
 315                 goto out_unlock;
 316         }
 317         if (rfkill->user_claim != claim) {
 318                 if (!claim)
 319                         rfkill_toggle_radio(rfkill,
 320                                             rfkill_states[rfkill->type],
 321                                             0);
 322                 rfkill->user_claim = claim;
 323         }
 324
 325 out_unlock:
 326         mutex_unlock(&rfkill_mutex);
 327
 328         return error ? error : count;
 329 }
 330
 331 static struct device_attribute rfkill_dev_attrs[] = {
 332         __ATTR(name, S_IRUGO, rfkill_name_show, NULL),
 333         __ATTR(type, S_IRUGO, rfkill_type_show, NULL),
 334         __ATTR(state, S_IRUGO|S_IWUSR, rfkill_state_show, rfkill_state_store),
 335         __ATTR(claim, S_IRUGO|S_IWUSR, rfkill_claim_show, rfkill_claim_store),
 336         __ATTR_NULL
 337 };
 338
 339 static void rfkill_release(struct device *dev)
 340 {
 341         struct rfkill *rfkill = to_rfkill(dev);
 342
 343         kfree(rfkill);
 344         module_put(THIS_MODULE);
 345 }
 346
 347 #ifdef CONFIG_PM
 348 static int rfkill_suspend(struct device *dev, pm_message_t state)
 349 {
 350         struct rfkill *rfkill = to_rfkill(dev);
 351
 352         if (dev->power.power_state.event != state.event) {
 353                 if (state.event & PM_EVENT_SLEEP) {
 354                         /* Stop transmitter, keep state, no notifies */
 355                         update_rfkill_state(rfkill);
 356
 357                         mutex_lock(&rfkill->mutex);
 358                         rfkill->toggle_radio(rfkill->data, RFKILL_STATE_OFF);
 359                         mutex_unlock(&rfkill->mutex);
 360                 }
 361
 362                 dev->power.power_state = state;
 363         }
 364
 365         return 0;
 366 }
 367
 368 static int rfkill_resume(struct device *dev)
 369 {
 370         struct rfkill *rfkill = to_rfkill(dev);
 371
 372         if (dev->power.power_state.event != PM_EVENT_ON) {
 373                 mutex_lock(&rfkill->mutex);
 374
 375                 /* restore radio state AND notify everybody */
 376                 rfkill_toggle_radio(rfkill, rfkill->state, 1);
 377
 378                 mutex_unlock(&rfkill->mutex);
 379         }
 380
 381         dev->power.power_state = PMSG_ON;
 382         return 0;
 383 }
 384 #else
 385 #define rfkill_suspend NULL
 386 #define rfkill_resume NULL
 387 #endif
 388
 389 static struct class rfkill_class = {
 390         .name           = "rfkill",
 391         .dev_release    = rfkill_release,
 392         .dev_attrs      = rfkill_dev_attrs,
 393         .suspend        = rfkill_suspend,
 394         .resume         = rfkill_resume,
 395 };
 396
 397 static int rfkill_add_switch(struct rfkill *rfkill)
 398 {
 399         int error;
 400
 401         mutex_lock(&rfkill_mutex);
 402
 403         error = rfkill_toggle_radio(rfkill, rfkill_states[rfkill->type], 0);
 404         if (!error)
 405                 list_add_tail(&rfkill->node, &rfkill_list);
 406
 407         mutex_unlock(&rfkill_mutex);
 408
 409         return error;
 410 }
 411
 412 static void rfkill_remove_switch(struct rfkill *rfkill)
 413 {
 414         mutex_lock(&rfkill_mutex);
 415         list_del_init(&rfkill->node);
 416         rfkill_toggle_radio(rfkill, RFKILL_STATE_OFF, 1);
 417         mutex_unlock(&rfkill_mutex);
 418 }
 419
 420 /**
 421  * rfkill_allocate - allocate memory for rfkill structure.
 422  * @parent: device that has rf switch on it
 423  * @type: type of the switch (RFKILL_TYPE_*)
 424  *
 425  * This function should be called by the network driver when it needs
 426  * rfkill structure. Once the structure is allocated the driver shoud
 427  * finish its initialization by setting name, private data, enable_radio
 428  * and disable_radio methods and then register it with rfkill_register().
 429  * NOTE: If registration fails the structure shoudl be freed by calling
 430  * rfkill_free() otherwise rfkill_unregister() should be used.
 431  */
 432 struct rfkill *rfkill_allocate(struct device *parent, enum rfkill_type type)
 433 {
 434         struct rfkill *rfkill;
 435         struct device *dev;
 436
 437         rfkill = kzalloc(sizeof(struct rfkill), GFP_KERNEL);
 438         if (!rfkill)
 439                 return NULL;
 440
 441         mutex_init(&rfkill->mutex);
 442         INIT_LIST_HEAD(&rfkill->node);
 443         rfkill->type = type;
 444
 445         dev = &rfkill->dev;
 446         dev->class = &rfkill_class;
 447         dev->parent = parent;
 448         device_initialize(dev);
 449
 450         __module_get(THIS_MODULE);
 451
 452         return rfkill;
 453 }
 454 EXPORT_SYMBOL(rfkill_allocate);
 455
 456 /**
 457  * rfkill_free - Mark rfkill structure for deletion
 458  * @rfkill: rfkill structure to be destroyed
 459  *
 460  * Decrements reference count of rfkill structure so it is destroyed.
 461  * Note that rfkill_free() should _not_ be called after rfkill_unregister().
 462  */
 463 void rfkill_free(struct rfkill *rfkill)
 464 {
 465         if (rfkill)
 466                 put_device(&rfkill->dev);
 467 }
 468 EXPORT_SYMBOL(rfkill_free);
 469
 470 static void rfkill_led_trigger_register(struct rfkill *rfkill)
 471 {
 472 #ifdef CONFIG_RFKILL_LEDS
 473         int error;
 474
 475         rfkill->led_trigger.name = rfkill->dev.bus_id;
 476         error = led_trigger_register(&rfkill->led_trigger);
 477         if (error)
 478                 rfkill->led_trigger.name = NULL;
 479 #endif /* CONFIG_RFKILL_LEDS */
 480 }
 481
 482 static void rfkill_led_trigger_unregister(struct rfkill *rfkill)
 483 {
 484 #ifdef CONFIG_RFKILL_LEDS
 485         if (rfkill->led_trigger.name)
 486                 led_trigger_unregister(&rfkill->led_trigger);
 487 #endif
 488 }
 489
 490 /**
 491  * rfkill_register - Register a rfkill structure.
 492  * @rfkill: rfkill structure to be registered
 493  *
 494  * This function should be called by the network driver when the rfkill
 495  * structure needs to be registered. Immediately from registration the
 496  * switch driver should be able to service calls to toggle_radio.
 497  */
 498 int rfkill_register(struct rfkill *rfkill)
 499 {
 500         static atomic_t rfkill_no = ATOMIC_INIT(0);
 501         struct device *dev = &rfkill->dev;
 502         int error;
 503
 504         if (!rfkill->toggle_radio)
 505                 return -EINVAL;
 506         if (rfkill->type >= RFKILL_TYPE_MAX)
 507                 return -EINVAL;
 508
 509         snprintf(dev->bus_id, sizeof(dev->bus_id),
 510                  "rfkill%ld", (long)atomic_inc_return(&rfkill_no) - 1);
 511
 512         rfkill_led_trigger_register(rfkill);
 513
 514         error = rfkill_add_switch(rfkill);
 515         if (error) {
 516                 rfkill_led_trigger_unregister(rfkill);
 517                 return error;
 518         }
 519
 520         error = device_add(dev);
 521         if (error) {
 522                 rfkill_led_trigger_unregister(rfkill);
 523                 rfkill_remove_switch(rfkill);
 524                 return error;
 525         }
 526
 527         return 0;
 528 }
 529 EXPORT_SYMBOL(rfkill_register);
 530
 531 /**
 532  * rfkill_unregister - Unregister a rfkill structure.
 533  * @rfkill: rfkill structure to be unregistered
 534  *
 535  * This function should be called by the network driver during device
 536  * teardown to destroy rfkill structure. Note that rfkill_free() should
 537  * _not_ be called after rfkill_unregister().
 538  */
 539 void rfkill_unregister(struct rfkill *rfkill)
 540 {
 541         device_del(&rfkill->dev);
 542         rfkill_remove_switch(rfkill);
 543         rfkill_led_trigger_unregister(rfkill);
 544         put_device(&rfkill->dev);
 545 }
 546 EXPORT_SYMBOL(rfkill_unregister);
 547
 548 /*
 549  * Rfkill module initialization/deinitialization.
 550  */
 551 static int __init rfkill_init(void)
 552 {
 553         int error;
 554         int i;
 555
 556         if (rfkill_default_state != RFKILL_STATE_OFF &&
 557             rfkill_default_state != RFKILL_STATE_ON)
 558                 return -EINVAL;
 559
 560         for (i = 0; i < ARRAY_SIZE(rfkill_states); i++)
 561                 rfkill_states[i] = rfkill_default_state;
 562
 563         error = class_register(&rfkill_class);
 564         if (error) {
 565                 printk(KERN_ERR "rfkill: unable to register rfkill class\n");
 566                 return error;
 567         }
 568
 569         return 0;
 570 }
 571
 572 static void __exit rfkill_exit(void)
 573 {
 574         class_unregister(&rfkill_class);
 575 }
 576
 577 subsys_initcall(rfkill_init);
 578 module_exit(rfkill_exit);