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_epo - emergency power off all transmitters
 186  *
 187  * This kicks all rfkill devices to RFKILL_STATE_OFF, ignoring
 188  * everything in its path but rfkill_mutex.
 189  */
 190 void rfkill_epo(void)
 191 {
 192         struct rfkill *rfkill;
 193
 194         mutex_lock(&rfkill_mutex);
 195         list_for_each_entry(rfkill, &rfkill_list, node) {
 196                 rfkill_toggle_radio(rfkill, RFKILL_STATE_OFF, 1);
 197         }
 198         mutex_unlock(&rfkill_mutex);
 199 }
 200 EXPORT_SYMBOL_GPL(rfkill_epo);
 201
 202 /**
 203  * rfkill_force_state - Force the internal rfkill radio state
 204  * @rfkill: pointer to the rfkill class to modify.
 205  * @state: the current radio state the class should be forced to.
 206  *
 207  * This function updates the internal state of the radio cached
 208  * by the rfkill class.  It should be used when the driver gets
 209  * a notification by the firmware/hardware of the current *real*
 210  * state of the radio rfkill switch.
 211  *
 212  * It may not be called from an atomic context.
 213  */
 214 int rfkill_force_state(struct rfkill *rfkill, enum rfkill_state state)
 215 {
 216         enum rfkill_state oldstate;
 217
 218         if (state != RFKILL_STATE_OFF &&
 219             state != RFKILL_STATE_ON)
 220                 return -EINVAL;
 221
 222         mutex_lock(&rfkill->mutex);
 223
 224         oldstate = rfkill->state;
 225         rfkill->state = state;
 226
 227         if (state != oldstate)
 228                 notify_rfkill_state_change(rfkill);
 229
 230         mutex_unlock(&rfkill->mutex);
 231
 232         return 0;
 233 }
 234 EXPORT_SYMBOL(rfkill_force_state);
 235
 236 static ssize_t rfkill_name_show(struct device *dev,
 237                                 struct device_attribute *attr,
 238                                 char *buf)
 239 {
 240         struct rfkill *rfkill = to_rfkill(dev);
 241
 242         return sprintf(buf, "%s\n", rfkill->name);
 243 }
 244
 245 static const char *rfkill_get_type_str(enum rfkill_type type)
 246 {
 247         switch (type) {
 248         case RFKILL_TYPE_WLAN:
 249                 return "wlan";
 250         case RFKILL_TYPE_BLUETOOTH:
 251                 return "bluetooth";
 252         case RFKILL_TYPE_UWB:
 253                 return "ultrawideband";
 254         case RFKILL_TYPE_WIMAX:
 255                 return "wimax";
 256         case RFKILL_TYPE_WWAN:
 257                 return "wwan";
 258         default:
 259                 BUG();
 260         }
 261 }
 262
 263 static ssize_t rfkill_type_show(struct device *dev,
 264                                 struct device_attribute *attr,
 265                                 char *buf)
 266 {
 267         struct rfkill *rfkill = to_rfkill(dev);
 268
 269         return sprintf(buf, "%s\n", rfkill_get_type_str(rfkill->type));
 270 }
 271
 272 static ssize_t rfkill_state_show(struct device *dev,
 273                                  struct device_attribute *attr,
 274                                  char *buf)
 275 {
 276         struct rfkill *rfkill = to_rfkill(dev);
 277
 278         update_rfkill_state(rfkill);
 279         return sprintf(buf, "%d\n", rfkill->state);
 280 }
 281
 282 static ssize_t rfkill_state_store(struct device *dev,
 283                                   struct device_attribute *attr,
 284                                   const char *buf, size_t count)
 285 {
 286         struct rfkill *rfkill = to_rfkill(dev);
 287         unsigned int state = simple_strtoul(buf, NULL, 0);
 288         int error;
 289
 290         if (!capable(CAP_NET_ADMIN))
 291                 return -EPERM;
 292
 293         if (mutex_lock_interruptible(&rfkill->mutex))
 294                 return -ERESTARTSYS;
 295         error = rfkill_toggle_radio(rfkill,
 296                         state ? RFKILL_STATE_ON : RFKILL_STATE_OFF,
 297                         0);
 298         mutex_unlock(&rfkill->mutex);
 299
 300         return error ? error : count;
 301 }
 302
 303 static ssize_t rfkill_claim_show(struct device *dev,
 304                                  struct device_attribute *attr,
 305                                  char *buf)
 306 {
 307         struct rfkill *rfkill = to_rfkill(dev);
 308
 309         return sprintf(buf, "%d", rfkill->user_claim);
 310 }
 311
 312 static ssize_t rfkill_claim_store(struct device *dev,
 313                                   struct device_attribute *attr,
 314                                   const char *buf, size_t count)
 315 {
 316         struct rfkill *rfkill = to_rfkill(dev);
 317         bool claim = !!simple_strtoul(buf, NULL, 0);
 318         int error;
 319
 320         if (!capable(CAP_NET_ADMIN))
 321                 return -EPERM;
 322
 323         /*
 324          * Take the global lock to make sure the kernel is not in
 325          * the middle of rfkill_switch_all
 326          */
 327         error = mutex_lock_interruptible(&rfkill_mutex);
 328         if (error)
 329                 return error;
 330
 331         if (rfkill->user_claim_unsupported) {
 332                 error = -EOPNOTSUPP;
 333                 goto out_unlock;
 334         }
 335         if (rfkill->user_claim != claim) {
 336                 if (!claim)
 337                         rfkill_toggle_radio(rfkill,
 338                                             rfkill_states[rfkill->type],
 339                                             0);
 340                 rfkill->user_claim = claim;
 341         }
 342
 343 out_unlock:
 344         mutex_unlock(&rfkill_mutex);
 345
 346         return error ? error : count;
 347 }
 348
 349 static struct device_attribute rfkill_dev_attrs[] = {
 350         __ATTR(name, S_IRUGO, rfkill_name_show, NULL),
 351         __ATTR(type, S_IRUGO, rfkill_type_show, NULL),
 352         __ATTR(state, S_IRUGO|S_IWUSR, rfkill_state_show, rfkill_state_store),
 353         __ATTR(claim, S_IRUGO|S_IWUSR, rfkill_claim_show, rfkill_claim_store),
 354         __ATTR_NULL
 355 };
 356
 357 static void rfkill_release(struct device *dev)
 358 {
 359         struct rfkill *rfkill = to_rfkill(dev);
 360
 361         kfree(rfkill);
 362         module_put(THIS_MODULE);
 363 }
 364
 365 #ifdef CONFIG_PM
 366 static int rfkill_suspend(struct device *dev, pm_message_t state)
 367 {
 368         struct rfkill *rfkill = to_rfkill(dev);
 369
 370         if (dev->power.power_state.event != state.event) {
 371                 if (state.event == PM_EVENT_SUSPEND) {
 372                         /* Stop transmitter, keep state, no notifies */
 373
 374                         update_rfkill_state(rfkill);
 375
 376                         mutex_lock(&rfkill->mutex);
 377                         rfkill->toggle_radio(rfkill->data, RFKILL_STATE_OFF);
 378                         mutex_unlock(&rfkill->mutex);
 379                 }
 380
 381                 dev->power.power_state = state;
 382         }
 383
 384         return 0;
 385 }
 386
 387 static int rfkill_resume(struct device *dev)
 388 {
 389         struct rfkill *rfkill = to_rfkill(dev);
 390
 391         if (dev->power.power_state.event != PM_EVENT_ON) {
 392                 mutex_lock(&rfkill->mutex);
 393
 394                 /* restore radio state AND notify everybody */
 395                 rfkill_toggle_radio(rfkill, rfkill->state, 1);
 396
 397                 mutex_unlock(&rfkill->mutex);
 398         }
 399
 400         dev->power.power_state = PMSG_ON;
 401         return 0;
 402 }
 403 #else
 404 #define rfkill_suspend NULL
 405 #define rfkill_resume NULL
 406 #endif
 407
 408 static int rfkill_blocking_uevent_notifier(struct notifier_block *nb,
 409                                         unsigned long eventid,
 410                                         void *data)
 411 {
 412         struct rfkill *rfkill = (struct rfkill *)data;
 413
 414         switch (eventid) {
 415         case RFKILL_STATE_CHANGED:
 416                 kobject_uevent(&rfkill->dev.kobj, KOBJ_CHANGE);
 417                 break;
 418         default:
 419                 break;
 420         }
 421
 422         return NOTIFY_DONE;
 423 }
 424
 425 static struct notifier_block rfkill_blocking_uevent_nb = {
 426         .notifier_call  = rfkill_blocking_uevent_notifier,
 427         .priority       = 0,
 428 };
 429
 430 static int rfkill_dev_uevent(struct device *dev, char **envp, int num_envp,
 431                       char *buffer, int buffer_size)
 432 {
 433         struct rfkill *rfkill = to_rfkill(dev);
 434         int i = 0, length = 0;
 435
 436         add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length,
 437                        "RFKILL_NAME=%s", rfkill->name);
 438         add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length,
 439                        "RFKILL_TYPE=%s", rfkill_get_type_str(rfkill->type));
 440         add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length,
 441                        "RFKILL_STATE=%d", rfkill->state);
 442         envp[i] = NULL;
 443         return 0;
 444 }
 445
 446 static struct class rfkill_class = {
 447         .name           = "rfkill",
 448         .dev_release    = rfkill_release,
 449         .dev_attrs      = rfkill_dev_attrs,
 450         .suspend        = rfkill_suspend,
 451         .resume         = rfkill_resume,
 452         .dev_uevent     = rfkill_dev_uevent,
 453 };
 454
 455 static int rfkill_add_switch(struct rfkill *rfkill)
 456 {
 457         int error;
 458
 459         mutex_lock(&rfkill_mutex);
 460
 461         error = rfkill_toggle_radio(rfkill, rfkill_states[rfkill->type], 0);
 462         if (!error)
 463                 list_add_tail(&rfkill->node, &rfkill_list);
 464
 465         mutex_unlock(&rfkill_mutex);
 466
 467         return error;
 468 }
 469
 470 static void rfkill_remove_switch(struct rfkill *rfkill)
 471 {
 472         mutex_lock(&rfkill_mutex);
 473         list_del_init(&rfkill->node);
 474         rfkill_toggle_radio(rfkill, RFKILL_STATE_OFF, 1);
 475         mutex_unlock(&rfkill_mutex);
 476 }
 477
 478 /**
 479  * rfkill_allocate - allocate memory for rfkill structure.
 480  * @parent: device that has rf switch on it
 481  * @type: type of the switch (RFKILL_TYPE_*)
 482  *
 483  * This function should be called by the network driver when it needs
 484  * rfkill structure. Once the structure is allocated the driver shoud
 485  * finish its initialization by setting name, private data, enable_radio
 486  * and disable_radio methods and then register it with rfkill_register().
 487  * NOTE: If registration fails the structure shoudl be freed by calling
 488  * rfkill_free() otherwise rfkill_unregister() should be used.
 489  */
 490 struct rfkill *rfkill_allocate(struct device *parent, enum rfkill_type type)
 491 {
 492         struct rfkill *rfkill;
 493         struct device *dev;
 494
 495         rfkill = kzalloc(sizeof(struct rfkill), GFP_KERNEL);
 496         if (!rfkill)
 497                 return NULL;
 498
 499         mutex_init(&rfkill->mutex);
 500         INIT_LIST_HEAD(&rfkill->node);
 501         rfkill->type = type;
 502
 503         dev = &rfkill->dev;
 504         dev->class = &rfkill_class;
 505         dev->parent = parent;
 506         device_initialize(dev);
 507
 508         __module_get(THIS_MODULE);
 509
 510         return rfkill;
 511 }
 512 EXPORT_SYMBOL(rfkill_allocate);
 513
 514 /**
 515  * rfkill_free - Mark rfkill structure for deletion
 516  * @rfkill: rfkill structure to be destroyed
 517  *
 518  * Decrements reference count of rfkill structure so it is destroyed.
 519  * Note that rfkill_free() should _not_ be called after rfkill_unregister().
 520  */
 521 void rfkill_free(struct rfkill *rfkill)
 522 {
 523         if (rfkill)
 524                 put_device(&rfkill->dev);
 525 }
 526 EXPORT_SYMBOL(rfkill_free);
 527
 528 static void rfkill_led_trigger_register(struct rfkill *rfkill)
 529 {
 530 #ifdef CONFIG_RFKILL_LEDS
 531         int error;
 532
 533         rfkill->led_trigger.name = rfkill->dev.bus_id;
 534         error = led_trigger_register(&rfkill->led_trigger);
 535         if (error)
 536                 rfkill->led_trigger.name = NULL;
 537 #endif /* CONFIG_RFKILL_LEDS */
 538 }
 539
 540 static void rfkill_led_trigger_unregister(struct rfkill *rfkill)
 541 {
 542 #ifdef CONFIG_RFKILL_LEDS
 543         if (rfkill->led_trigger.name)
 544                 led_trigger_unregister(&rfkill->led_trigger);
 545 #endif
 546 }
 547
 548 /**
 549  * rfkill_register - Register a rfkill structure.
 550  * @rfkill: rfkill structure to be registered
 551  *
 552  * This function should be called by the network driver when the rfkill
 553  * structure needs to be registered. Immediately from registration the
 554  * switch driver should be able to service calls to toggle_radio.
 555  */
 556 int rfkill_register(struct rfkill *rfkill)
 557 {
 558         static atomic_t rfkill_no = ATOMIC_INIT(0);
 559         struct device *dev = &rfkill->dev;
 560         int error;
 561
 562         if (!rfkill->toggle_radio)
 563                 return -EINVAL;
 564         if (rfkill->type >= RFKILL_TYPE_MAX)
 565                 return -EINVAL;
 566
 567         snprintf(dev->bus_id, sizeof(dev->bus_id),
 568                  "rfkill%ld", (long)atomic_inc_return(&rfkill_no) - 1);
 569
 570         rfkill_led_trigger_register(rfkill);
 571
 572         error = rfkill_add_switch(rfkill);
 573         if (error) {
 574                 rfkill_led_trigger_unregister(rfkill);
 575                 return error;
 576         }
 577
 578         error = device_add(dev);
 579         if (error) {
 580                 rfkill_led_trigger_unregister(rfkill);
 581                 rfkill_remove_switch(rfkill);
 582                 return error;
 583         }
 584
 585         return 0;
 586 }
 587 EXPORT_SYMBOL(rfkill_register);
 588
 589 /**
 590  * rfkill_unregister - Unregister a rfkill structure.
 591  * @rfkill: rfkill structure to be unregistered
 592  *
 593  * This function should be called by the network driver during device
 594  * teardown to destroy rfkill structure. Note that rfkill_free() should
 595  * _not_ be called after rfkill_unregister().
 596  */
 597 void rfkill_unregister(struct rfkill *rfkill)
 598 {
 599         device_del(&rfkill->dev);
 600         rfkill_remove_switch(rfkill);
 601         rfkill_led_trigger_unregister(rfkill);
 602         put_device(&rfkill->dev);
 603 }
 604 EXPORT_SYMBOL(rfkill_unregister);
 605
 606 /*
 607  * Rfkill module initialization/deinitialization.
 608  */
 609 static int __init rfkill_init(void)
 610 {
 611         int error;
 612         int i;
 613
 614         if (rfkill_default_state != RFKILL_STATE_OFF &&
 615             rfkill_default_state != RFKILL_STATE_ON)
 616                 return -EINVAL;
 617
 618         for (i = 0; i < ARRAY_SIZE(rfkill_states); i++)
 619                 rfkill_states[i] = rfkill_default_state;
 620
 621         error = class_register(&rfkill_class);
 622         if (error) {
 623                 printk(KERN_ERR "rfkill: unable to register rfkill class\n");
 624                 return error;
 625         }
 626
 627         register_rfkill_notifier(&rfkill_blocking_uevent_nb);
 628
 629         return 0;
 630 }
 631
 632 static void __exit rfkill_exit(void)
 633 {
 634         unregister_rfkill_notifier(&rfkill_blocking_uevent_nb);
 635         class_unregister(&rfkill_class);
 636 }
 637
 638 subsys_initcall(rfkill_init);
 639 module_exit(rfkill_exit);