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[linux-2.6] / 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_UNBLOCKED;
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_UNBLOCKED)
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 /**
132  * rfkill_toggle_radio - wrapper for toggle_radio hook
133  *
134  * @rfkill: the rfkill struct to use
135  * @force: calls toggle_radio even if cache says it is not needed,
136  *      and also makes sure notifications of the state will be
137  *      sent even if it didn't change
138  * @state: the new state to call toggle_radio() with
139  *
140  * Calls rfkill->toggle_radio, enforcing the API for toggle_radio
141  * calls and handling all the red tape such as issuing notifications
142  * if the call is successful.
143  *
144  * Note that @force cannot override a (possibly cached) state of
145  * RFKILL_STATE_HARD_BLOCKED.  Any device making use of
146  * RFKILL_STATE_HARD_BLOCKED implements either get_state() or
147  * rfkill_force_state(), so the cache either is bypassed or valid.
148  *
149  * Note that we do call toggle_radio for RFKILL_STATE_SOFT_BLOCKED
150  * even if the radio is in RFKILL_STATE_HARD_BLOCKED state, so as to
151  * give the driver a hint that it should double-BLOCK the transmitter.
152  *
153  * Caller must have aquired rfkill_mutex.
154  */
155 static int rfkill_toggle_radio(struct rfkill *rfkill,
156                                 enum rfkill_state state,
157                                 int force)
158 {
159         int retval = 0;
160         enum rfkill_state oldstate, newstate;
161
162         oldstate = rfkill->state;
163
164         if (rfkill->get_state && !force &&
165             !rfkill->get_state(rfkill->data, &newstate))
166                 rfkill->state = newstate;
167
168         switch (state) {
169         case RFKILL_STATE_HARD_BLOCKED:
170                 /* typically happens when refreshing hardware state,
171                  * such as on resume */
172                 state = RFKILL_STATE_SOFT_BLOCKED;
173                 break;
174         case RFKILL_STATE_UNBLOCKED:
175                 /* force can't override this, only rfkill_force_state() can */
176                 if (rfkill->state == RFKILL_STATE_HARD_BLOCKED)
177                         return -EPERM;
178                 break;
179         case RFKILL_STATE_SOFT_BLOCKED:
180                 /* nothing to do, we want to give drivers the hint to double
181                  * BLOCK even a transmitter that is already in state
182                  * RFKILL_STATE_HARD_BLOCKED */
183                 break;
184         }
185
186         if (force || state != rfkill->state) {
187                 retval = rfkill->toggle_radio(rfkill->data, state);
188                 /* never allow a HARD->SOFT downgrade! */
189                 if (!retval && rfkill->state != RFKILL_STATE_HARD_BLOCKED)
190                         rfkill->state = state;
191         }
192
193         if (force || rfkill->state != oldstate) {
194                 rfkill_led_trigger(rfkill, rfkill->state);
195                 notify_rfkill_state_change(rfkill);
196         }
197
198         return retval;
199 }
200
201 /**
202  * rfkill_switch_all - Toggle state of all switches of given type
203  * @type: type of interfaces to be affeceted
204  * @state: the new state
205  *
206  * This function toggles state of all switches of given type unless
207  * a specific switch is claimed by userspace in which case it is
208  * left alone.
209  */
210 void rfkill_switch_all(enum rfkill_type type, enum rfkill_state state)
211 {
212         struct rfkill *rfkill;
213
214         mutex_lock(&rfkill_mutex);
215
216         rfkill_states[type] = state;
217
218         list_for_each_entry(rfkill, &rfkill_list, node) {
219                 if ((!rfkill->user_claim) && (rfkill->type == type))
220                         rfkill_toggle_radio(rfkill, state, 0);
221         }
222
223         mutex_unlock(&rfkill_mutex);
224 }
225 EXPORT_SYMBOL(rfkill_switch_all);
226
227 /**
228  * rfkill_epo - emergency power off all transmitters
229  *
230  * This kicks all rfkill devices to RFKILL_STATE_SOFT_BLOCKED, ignoring
231  * everything in its path but rfkill_mutex.
232  */
233 void rfkill_epo(void)
234 {
235         struct rfkill *rfkill;
236
237         mutex_lock(&rfkill_mutex);
238         list_for_each_entry(rfkill, &rfkill_list, node) {
239                 rfkill_toggle_radio(rfkill, RFKILL_STATE_SOFT_BLOCKED, 1);
240         }
241         mutex_unlock(&rfkill_mutex);
242 }
243 EXPORT_SYMBOL_GPL(rfkill_epo);
244
245 /**
246  * rfkill_force_state - Force the internal rfkill radio state
247  * @rfkill: pointer to the rfkill class to modify.
248  * @state: the current radio state the class should be forced to.
249  *
250  * This function updates the internal state of the radio cached
251  * by the rfkill class.  It should be used when the driver gets
252  * a notification by the firmware/hardware of the current *real*
253  * state of the radio rfkill switch.
254  *
255  * It may not be called from an atomic context.
256  */
257 int rfkill_force_state(struct rfkill *rfkill, enum rfkill_state state)
258 {
259         enum rfkill_state oldstate;
260
261         if (state != RFKILL_STATE_SOFT_BLOCKED &&
262             state != RFKILL_STATE_UNBLOCKED &&
263             state != RFKILL_STATE_HARD_BLOCKED)
264                 return -EINVAL;
265
266         mutex_lock(&rfkill->mutex);
267
268         oldstate = rfkill->state;
269         rfkill->state = state;
270
271         if (state != oldstate)
272                 notify_rfkill_state_change(rfkill);
273
274         mutex_unlock(&rfkill->mutex);
275
276         return 0;
277 }
278 EXPORT_SYMBOL(rfkill_force_state);
279
280 static ssize_t rfkill_name_show(struct device *dev,
281                                 struct device_attribute *attr,
282                                 char *buf)
283 {
284         struct rfkill *rfkill = to_rfkill(dev);
285
286         return sprintf(buf, "%s\n", rfkill->name);
287 }
288
289 static const char *rfkill_get_type_str(enum rfkill_type type)
290 {
291         switch (type) {
292         case RFKILL_TYPE_WLAN:
293                 return "wlan";
294         case RFKILL_TYPE_BLUETOOTH:
295                 return "bluetooth";
296         case RFKILL_TYPE_UWB:
297                 return "ultrawideband";
298         case RFKILL_TYPE_WIMAX:
299                 return "wimax";
300         case RFKILL_TYPE_WWAN:
301                 return "wwan";
302         default:
303                 BUG();
304         }
305 }
306
307 static ssize_t rfkill_type_show(struct device *dev,
308                                 struct device_attribute *attr,
309                                 char *buf)
310 {
311         struct rfkill *rfkill = to_rfkill(dev);
312
313         return sprintf(buf, "%s\n", rfkill_get_type_str(rfkill->type));
314 }
315
316 static ssize_t rfkill_state_show(struct device *dev,
317                                  struct device_attribute *attr,
318                                  char *buf)
319 {
320         struct rfkill *rfkill = to_rfkill(dev);
321
322         update_rfkill_state(rfkill);
323         return sprintf(buf, "%d\n", rfkill->state);
324 }
325
326 static ssize_t rfkill_state_store(struct device *dev,
327                                   struct device_attribute *attr,
328                                   const char *buf, size_t count)
329 {
330         struct rfkill *rfkill = to_rfkill(dev);
331         unsigned int state = simple_strtoul(buf, NULL, 0);
332         int error;
333
334         if (!capable(CAP_NET_ADMIN))
335                 return -EPERM;
336
337         /* RFKILL_STATE_HARD_BLOCKED is illegal here... */
338         if (state != RFKILL_STATE_UNBLOCKED &&
339             state != RFKILL_STATE_SOFT_BLOCKED)
340                 return -EINVAL;
341
342         if (mutex_lock_interruptible(&rfkill->mutex))
343                 return -ERESTARTSYS;
344         error = rfkill_toggle_radio(rfkill, state, 0);
345         mutex_unlock(&rfkill->mutex);
346
347         return error ? error : count;
348 }
349
350 static ssize_t rfkill_claim_show(struct device *dev,
351                                  struct device_attribute *attr,
352                                  char *buf)
353 {
354         struct rfkill *rfkill = to_rfkill(dev);
355
356         return sprintf(buf, "%d", rfkill->user_claim);
357 }
358
359 static ssize_t rfkill_claim_store(struct device *dev,
360                                   struct device_attribute *attr,
361                                   const char *buf, size_t count)
362 {
363         struct rfkill *rfkill = to_rfkill(dev);
364         bool claim = !!simple_strtoul(buf, NULL, 0);
365         int error;
366
367         if (!capable(CAP_NET_ADMIN))
368                 return -EPERM;
369
370         /*
371          * Take the global lock to make sure the kernel is not in
372          * the middle of rfkill_switch_all
373          */
374         error = mutex_lock_interruptible(&rfkill_mutex);
375         if (error)
376                 return error;
377
378         if (rfkill->user_claim_unsupported) {
379                 error = -EOPNOTSUPP;
380                 goto out_unlock;
381         }
382         if (rfkill->user_claim != claim) {
383                 if (!claim)
384                         rfkill_toggle_radio(rfkill,
385                                             rfkill_states[rfkill->type],
386                                             0);
387                 rfkill->user_claim = claim;
388         }
389
390 out_unlock:
391         mutex_unlock(&rfkill_mutex);
392
393         return error ? error : count;
394 }
395
396 static struct device_attribute rfkill_dev_attrs[] = {
397         __ATTR(name, S_IRUGO, rfkill_name_show, NULL),
398         __ATTR(type, S_IRUGO, rfkill_type_show, NULL),
399         __ATTR(state, S_IRUGO|S_IWUSR, rfkill_state_show, rfkill_state_store),
400         __ATTR(claim, S_IRUGO|S_IWUSR, rfkill_claim_show, rfkill_claim_store),
401         __ATTR_NULL
402 };
403
404 static void rfkill_release(struct device *dev)
405 {
406         struct rfkill *rfkill = to_rfkill(dev);
407
408         kfree(rfkill);
409         module_put(THIS_MODULE);
410 }
411
412 #ifdef CONFIG_PM
413 static int rfkill_suspend(struct device *dev, pm_message_t state)
414 {
415         struct rfkill *rfkill = to_rfkill(dev);
416
417         if (dev->power.power_state.event != state.event) {
418                 if (state.event & PM_EVENT_SLEEP) {
419                         /* Stop transmitter, keep state, no notifies */
420                         update_rfkill_state(rfkill);
421
422                         mutex_lock(&rfkill->mutex);
423                         rfkill->toggle_radio(rfkill->data,
424                                                 RFKILL_STATE_SOFT_BLOCKED);
425                         mutex_unlock(&rfkill->mutex);
426                 }
427
428                 dev->power.power_state = state;
429         }
430
431         return 0;
432 }
433
434 static int rfkill_resume(struct device *dev)
435 {
436         struct rfkill *rfkill = to_rfkill(dev);
437
438         if (dev->power.power_state.event != PM_EVENT_ON) {
439                 mutex_lock(&rfkill->mutex);
440
441                 /* restore radio state AND notify everybody */
442                 rfkill_toggle_radio(rfkill, rfkill->state, 1);
443
444                 mutex_unlock(&rfkill->mutex);
445         }
446
447         dev->power.power_state = PMSG_ON;
448         return 0;
449 }
450 #else
451 #define rfkill_suspend NULL
452 #define rfkill_resume NULL
453 #endif
454
455 static int rfkill_blocking_uevent_notifier(struct notifier_block *nb,
456                                         unsigned long eventid,
457                                         void *data)
458 {
459         struct rfkill *rfkill = (struct rfkill *)data;
460
461         switch (eventid) {
462         case RFKILL_STATE_CHANGED:
463                 kobject_uevent(&rfkill->dev.kobj, KOBJ_CHANGE);
464                 break;
465         default:
466                 break;
467         }
468
469         return NOTIFY_DONE;
470 }
471
472 static struct notifier_block rfkill_blocking_uevent_nb = {
473         .notifier_call  = rfkill_blocking_uevent_notifier,
474         .priority       = 0,
475 };
476
477 static int rfkill_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
478 {
479         struct rfkill *rfkill = to_rfkill(dev);
480         int error;
481
482         error = add_uevent_var(env, "RFKILL_NAME=%s", rfkill->name);
483         if (error)
484                 return error;
485         error = add_uevent_var(env, "RFKILL_TYPE=%s",
486                                 rfkill_get_type_str(rfkill->type));
487         if (error)
488                 return error;
489         error = add_uevent_var(env, "RFKILL_STATE=%d", rfkill->state);
490         return error;
491 }
492
493 static struct class rfkill_class = {
494         .name           = "rfkill",
495         .dev_release    = rfkill_release,
496         .dev_attrs      = rfkill_dev_attrs,
497         .suspend        = rfkill_suspend,
498         .resume         = rfkill_resume,
499         .dev_uevent     = rfkill_dev_uevent,
500 };
501
502 static int rfkill_add_switch(struct rfkill *rfkill)
503 {
504         mutex_lock(&rfkill_mutex);
505
506         rfkill_toggle_radio(rfkill, rfkill_states[rfkill->type], 0);
507
508         list_add_tail(&rfkill->node, &rfkill_list);
509
510         mutex_unlock(&rfkill_mutex);
511
512         return 0;
513 }
514
515 static void rfkill_remove_switch(struct rfkill *rfkill)
516 {
517         mutex_lock(&rfkill_mutex);
518         list_del_init(&rfkill->node);
519         rfkill_toggle_radio(rfkill, RFKILL_STATE_SOFT_BLOCKED, 1);
520         mutex_unlock(&rfkill_mutex);
521 }
522
523 /**
524  * rfkill_allocate - allocate memory for rfkill structure.
525  * @parent: device that has rf switch on it
526  * @type: type of the switch (RFKILL_TYPE_*)
527  *
528  * This function should be called by the network driver when it needs
529  * rfkill structure. Once the structure is allocated the driver shoud
530  * finish its initialization by setting name, private data, enable_radio
531  * and disable_radio methods and then register it with rfkill_register().
532  * NOTE: If registration fails the structure shoudl be freed by calling
533  * rfkill_free() otherwise rfkill_unregister() should be used.
534  */
535 struct rfkill *rfkill_allocate(struct device *parent, enum rfkill_type type)
536 {
537         struct rfkill *rfkill;
538         struct device *dev;
539
540         rfkill = kzalloc(sizeof(struct rfkill), GFP_KERNEL);
541         if (!rfkill)
542                 return NULL;
543
544         mutex_init(&rfkill->mutex);
545         INIT_LIST_HEAD(&rfkill->node);
546         rfkill->type = type;
547
548         dev = &rfkill->dev;
549         dev->class = &rfkill_class;
550         dev->parent = parent;
551         device_initialize(dev);
552
553         __module_get(THIS_MODULE);
554
555         return rfkill;
556 }
557 EXPORT_SYMBOL(rfkill_allocate);
558
559 /**
560  * rfkill_free - Mark rfkill structure for deletion
561  * @rfkill: rfkill structure to be destroyed
562  *
563  * Decrements reference count of rfkill structure so it is destroyed.
564  * Note that rfkill_free() should _not_ be called after rfkill_unregister().
565  */
566 void rfkill_free(struct rfkill *rfkill)
567 {
568         if (rfkill)
569                 put_device(&rfkill->dev);
570 }
571 EXPORT_SYMBOL(rfkill_free);
572
573 static void rfkill_led_trigger_register(struct rfkill *rfkill)
574 {
575 #ifdef CONFIG_RFKILL_LEDS
576         int error;
577
578         rfkill->led_trigger.name = rfkill->dev.bus_id;
579         error = led_trigger_register(&rfkill->led_trigger);
580         if (error)
581                 rfkill->led_trigger.name = NULL;
582 #endif /* CONFIG_RFKILL_LEDS */
583 }
584
585 static void rfkill_led_trigger_unregister(struct rfkill *rfkill)
586 {
587 #ifdef CONFIG_RFKILL_LEDS
588         if (rfkill->led_trigger.name)
589                 led_trigger_unregister(&rfkill->led_trigger);
590 #endif
591 }
592
593 /**
594  * rfkill_register - Register a rfkill structure.
595  * @rfkill: rfkill structure to be registered
596  *
597  * This function should be called by the network driver when the rfkill
598  * structure needs to be registered. Immediately from registration the
599  * switch driver should be able to service calls to toggle_radio.
600  */
601 int rfkill_register(struct rfkill *rfkill)
602 {
603         static atomic_t rfkill_no = ATOMIC_INIT(0);
604         struct device *dev = &rfkill->dev;
605         int error;
606
607         if (!rfkill->toggle_radio)
608                 return -EINVAL;
609         if (rfkill->type >= RFKILL_TYPE_MAX)
610                 return -EINVAL;
611
612         snprintf(dev->bus_id, sizeof(dev->bus_id),
613                  "rfkill%ld", (long)atomic_inc_return(&rfkill_no) - 1);
614
615         rfkill_led_trigger_register(rfkill);
616
617         error = rfkill_add_switch(rfkill);
618         if (error) {
619                 rfkill_led_trigger_unregister(rfkill);
620                 return error;
621         }
622
623         error = device_add(dev);
624         if (error) {
625                 rfkill_led_trigger_unregister(rfkill);
626                 rfkill_remove_switch(rfkill);
627                 return error;
628         }
629
630         return 0;
631 }
632 EXPORT_SYMBOL(rfkill_register);
633
634 /**
635  * rfkill_unregister - Unregister a rfkill structure.
636  * @rfkill: rfkill structure to be unregistered
637  *
638  * This function should be called by the network driver during device
639  * teardown to destroy rfkill structure. Note that rfkill_free() should
640  * _not_ be called after rfkill_unregister().
641  */
642 void rfkill_unregister(struct rfkill *rfkill)
643 {
644         device_del(&rfkill->dev);
645         rfkill_remove_switch(rfkill);
646         rfkill_led_trigger_unregister(rfkill);
647         put_device(&rfkill->dev);
648 }
649 EXPORT_SYMBOL(rfkill_unregister);
650
651 /*
652  * Rfkill module initialization/deinitialization.
653  */
654 static int __init rfkill_init(void)
655 {
656         int error;
657         int i;
658
659         /* RFKILL_STATE_HARD_BLOCKED is illegal here... */
660         if (rfkill_default_state != RFKILL_STATE_SOFT_BLOCKED &&
661             rfkill_default_state != RFKILL_STATE_UNBLOCKED)
662                 return -EINVAL;
663
664         for (i = 0; i < ARRAY_SIZE(rfkill_states); i++)
665                 rfkill_states[i] = rfkill_default_state;
666
667         error = class_register(&rfkill_class);
668         if (error) {
669                 printk(KERN_ERR "rfkill: unable to register rfkill class\n");
670                 return error;
671         }
672
673         register_rfkill_notifier(&rfkill_blocking_uevent_nb);
674
675         return 0;
676 }
677
678 static void __exit rfkill_exit(void)
679 {
680         unregister_rfkill_notifier(&rfkill_blocking_uevent_nb);
681         class_unregister(&rfkill_class);
682 }
683
684 subsys_initcall(rfkill_init);
685 module_exit(rfkill_exit);