rfkill: rename the rfkill_state states and add block-locked state
[linux-2.6.git] / 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  * calls toggle_radio taking into account a lot of "small"
134  * details.
135  * @rfkill: the rfkill struct to use
136  * @force: calls toggle_radio even if cache says it is not needed,
137  *      and also makes sure notifications of the state will be
138  *      sent even if it didn't change
139  * @state: the new state to call toggle_radio() with
140  *
141  * This wrappen protects and enforces the API for toggle_radio
142  * calls.  Note that @force cannot override a (possibly cached)
143  * state of RFKILL_STATE_HARD_BLOCKED.  Any device making use of
144  * RFKILL_STATE_HARD_BLOCKED implements either get_state() or
145  * rfkill_force_state(), so the cache either is bypassed or valid.
146  *
147  * Note that we do call toggle_radio for RFKILL_STATE_SOFT_BLOCKED
148  * even if the radio is in RFKILL_STATE_HARD_BLOCKED state, so as to
149  * give the driver a hint that it should double-BLOCK the transmitter.
150  *
151  * Caller must have aquired rfkill_mutex.
152  */
153 static int rfkill_toggle_radio(struct rfkill *rfkill,
154                                 enum rfkill_state state,
155                                 int force)
156 {
157         int retval = 0;
158         enum rfkill_state oldstate, newstate;
159
160         oldstate = rfkill->state;
161
162         if (rfkill->get_state && !force &&
163             !rfkill->get_state(rfkill->data, &newstate))
164                 rfkill->state = newstate;
165
166         switch (state) {
167         case RFKILL_STATE_HARD_BLOCKED:
168                 /* typically happens when refreshing hardware state,
169                  * such as on resume */
170                 state = RFKILL_STATE_SOFT_BLOCKED;
171                 break;
172         case RFKILL_STATE_UNBLOCKED:
173                 /* force can't override this, only rfkill_force_state() can */
174                 if (rfkill->state == RFKILL_STATE_HARD_BLOCKED)
175                         return -EPERM;
176                 break;
177         case RFKILL_STATE_SOFT_BLOCKED:
178                 /* nothing to do, we want to give drivers the hint to double
179                  * BLOCK even a transmitter that is already in state
180                  * RFKILL_STATE_HARD_BLOCKED */
181                 break;
182         }
183
184         if (force || state != rfkill->state) {
185                 retval = rfkill->toggle_radio(rfkill->data, state);
186                 /* never allow a HARD->SOFT downgrade! */
187                 if (!retval && rfkill->state != RFKILL_STATE_HARD_BLOCKED)
188                         rfkill->state = state;
189         }
190
191         if (force || rfkill->state != oldstate) {
192                 rfkill_led_trigger(rfkill, rfkill->state);
193                 notify_rfkill_state_change(rfkill);
194         }
195
196         return retval;
197 }
198
199 /**
200  * rfkill_switch_all - Toggle state of all switches of given type
201  * @type: type of interfaces to be affeceted
202  * @state: the new state
203  *
204  * This function toggles state of all switches of given type unless
205  * a specific switch is claimed by userspace in which case it is
206  * left alone.
207  */
208 void rfkill_switch_all(enum rfkill_type type, enum rfkill_state state)
209 {
210         struct rfkill *rfkill;
211
212         mutex_lock(&rfkill_mutex);
213
214         rfkill_states[type] = state;
215
216         list_for_each_entry(rfkill, &rfkill_list, node) {
217                 if ((!rfkill->user_claim) && (rfkill->type == type))
218                         rfkill_toggle_radio(rfkill, state, 0);
219         }
220
221         mutex_unlock(&rfkill_mutex);
222 }
223 EXPORT_SYMBOL(rfkill_switch_all);
224
225 /**
226  * rfkill_epo - emergency power off all transmitters
227  *
228  * This kicks all rfkill devices to RFKILL_STATE_SOFT_BLOCKED, ignoring
229  * everything in its path but rfkill_mutex.
230  */
231 void rfkill_epo(void)
232 {
233         struct rfkill *rfkill;
234
235         mutex_lock(&rfkill_mutex);
236         list_for_each_entry(rfkill, &rfkill_list, node) {
237                 rfkill_toggle_radio(rfkill, RFKILL_STATE_SOFT_BLOCKED, 1);
238         }
239         mutex_unlock(&rfkill_mutex);
240 }
241 EXPORT_SYMBOL_GPL(rfkill_epo);
242
243 /**
244  * rfkill_force_state - Force the internal rfkill radio state
245  * @rfkill: pointer to the rfkill class to modify.
246  * @state: the current radio state the class should be forced to.
247  *
248  * This function updates the internal state of the radio cached
249  * by the rfkill class.  It should be used when the driver gets
250  * a notification by the firmware/hardware of the current *real*
251  * state of the radio rfkill switch.
252  *
253  * It may not be called from an atomic context.
254  */
255 int rfkill_force_state(struct rfkill *rfkill, enum rfkill_state state)
256 {
257         enum rfkill_state oldstate;
258
259         if (state != RFKILL_STATE_SOFT_BLOCKED &&
260             state != RFKILL_STATE_UNBLOCKED &&
261             state != RFKILL_STATE_HARD_BLOCKED)
262                 return -EINVAL;
263
264         mutex_lock(&rfkill->mutex);
265
266         oldstate = rfkill->state;
267         rfkill->state = state;
268
269         if (state != oldstate)
270                 notify_rfkill_state_change(rfkill);
271
272         mutex_unlock(&rfkill->mutex);
273
274         return 0;
275 }
276 EXPORT_SYMBOL(rfkill_force_state);
277
278 static ssize_t rfkill_name_show(struct device *dev,
279                                 struct device_attribute *attr,
280                                 char *buf)
281 {
282         struct rfkill *rfkill = to_rfkill(dev);
283
284         return sprintf(buf, "%s\n", rfkill->name);
285 }
286
287 static const char *rfkill_get_type_str(enum rfkill_type type)
288 {
289         switch (type) {
290         case RFKILL_TYPE_WLAN:
291                 return "wlan";
292         case RFKILL_TYPE_BLUETOOTH:
293                 return "bluetooth";
294         case RFKILL_TYPE_UWB:
295                 return "ultrawideband";
296         case RFKILL_TYPE_WIMAX:
297                 return "wimax";
298         case RFKILL_TYPE_WWAN:
299                 return "wwan";
300         default:
301                 BUG();
302         }
303 }
304
305 static ssize_t rfkill_type_show(struct device *dev,
306                                 struct device_attribute *attr,
307                                 char *buf)
308 {
309         struct rfkill *rfkill = to_rfkill(dev);
310
311         return sprintf(buf, "%s\n", rfkill_get_type_str(rfkill->type));
312 }
313
314 static ssize_t rfkill_state_show(struct device *dev,
315                                  struct device_attribute *attr,
316                                  char *buf)
317 {
318         struct rfkill *rfkill = to_rfkill(dev);
319
320         update_rfkill_state(rfkill);
321         return sprintf(buf, "%d\n", rfkill->state);
322 }
323
324 static ssize_t rfkill_state_store(struct device *dev,
325                                   struct device_attribute *attr,
326                                   const char *buf, size_t count)
327 {
328         struct rfkill *rfkill = to_rfkill(dev);
329         unsigned int state = simple_strtoul(buf, NULL, 0);
330         int error;
331
332         if (!capable(CAP_NET_ADMIN))
333                 return -EPERM;
334
335         /* RFKILL_STATE_HARD_BLOCKED is illegal here... */
336         if (state != RFKILL_STATE_UNBLOCKED &&
337             state != RFKILL_STATE_SOFT_BLOCKED)
338                 return -EINVAL;
339
340         if (mutex_lock_interruptible(&rfkill->mutex))
341                 return -ERESTARTSYS;
342         error = rfkill_toggle_radio(rfkill, state, 0);
343         mutex_unlock(&rfkill->mutex);
344
345         return error ? error : count;
346 }
347
348 static ssize_t rfkill_claim_show(struct device *dev,
349                                  struct device_attribute *attr,
350                                  char *buf)
351 {
352         struct rfkill *rfkill = to_rfkill(dev);
353
354         return sprintf(buf, "%d", rfkill->user_claim);
355 }
356
357 static ssize_t rfkill_claim_store(struct device *dev,
358                                   struct device_attribute *attr,
359                                   const char *buf, size_t count)
360 {
361         struct rfkill *rfkill = to_rfkill(dev);
362         bool claim = !!simple_strtoul(buf, NULL, 0);
363         int error;
364
365         if (!capable(CAP_NET_ADMIN))
366                 return -EPERM;
367
368         /*
369          * Take the global lock to make sure the kernel is not in
370          * the middle of rfkill_switch_all
371          */
372         error = mutex_lock_interruptible(&rfkill_mutex);
373         if (error)
374                 return error;
375
376         if (rfkill->user_claim_unsupported) {
377                 error = -EOPNOTSUPP;
378                 goto out_unlock;
379         }
380         if (rfkill->user_claim != claim) {
381                 if (!claim)
382                         rfkill_toggle_radio(rfkill,
383                                             rfkill_states[rfkill->type],
384                                             0);
385                 rfkill->user_claim = claim;
386         }
387
388 out_unlock:
389         mutex_unlock(&rfkill_mutex);
390
391         return error ? error : count;
392 }
393
394 static struct device_attribute rfkill_dev_attrs[] = {
395         __ATTR(name, S_IRUGO, rfkill_name_show, NULL),
396         __ATTR(type, S_IRUGO, rfkill_type_show, NULL),
397         __ATTR(state, S_IRUGO|S_IWUSR, rfkill_state_show, rfkill_state_store),
398         __ATTR(claim, S_IRUGO|S_IWUSR, rfkill_claim_show, rfkill_claim_store),
399         __ATTR_NULL
400 };
401
402 static void rfkill_release(struct device *dev)
403 {
404         struct rfkill *rfkill = to_rfkill(dev);
405
406         kfree(rfkill);
407         module_put(THIS_MODULE);
408 }
409
410 #ifdef CONFIG_PM
411 static int rfkill_suspend(struct device *dev, pm_message_t state)
412 {
413         struct rfkill *rfkill = to_rfkill(dev);
414
415         if (dev->power.power_state.event != state.event) {
416                 if (state.event & PM_EVENT_SLEEP) {
417                         /* Stop transmitter, keep state, no notifies */
418                         update_rfkill_state(rfkill);
419
420                         mutex_lock(&rfkill->mutex);
421                         rfkill->toggle_radio(rfkill->data,
422                                                 RFKILL_STATE_SOFT_BLOCKED);
423                         mutex_unlock(&rfkill->mutex);
424                 }
425
426                 dev->power.power_state = state;
427         }
428
429         return 0;
430 }
431
432 static int rfkill_resume(struct device *dev)
433 {
434         struct rfkill *rfkill = to_rfkill(dev);
435
436         if (dev->power.power_state.event != PM_EVENT_ON) {
437                 mutex_lock(&rfkill->mutex);
438
439                 /* restore radio state AND notify everybody */
440                 rfkill_toggle_radio(rfkill, rfkill->state, 1);
441
442                 mutex_unlock(&rfkill->mutex);
443         }
444
445         dev->power.power_state = PMSG_ON;
446         return 0;
447 }
448 #else
449 #define rfkill_suspend NULL
450 #define rfkill_resume NULL
451 #endif
452
453 static int rfkill_blocking_uevent_notifier(struct notifier_block *nb,
454                                         unsigned long eventid,
455                                         void *data)
456 {
457         struct rfkill *rfkill = (struct rfkill *)data;
458
459         switch (eventid) {
460         case RFKILL_STATE_CHANGED:
461                 kobject_uevent(&rfkill->dev.kobj, KOBJ_CHANGE);
462                 break;
463         default:
464                 break;
465         }
466
467         return NOTIFY_DONE;
468 }
469
470 static struct notifier_block rfkill_blocking_uevent_nb = {
471         .notifier_call  = rfkill_blocking_uevent_notifier,
472         .priority       = 0,
473 };
474
475 static int rfkill_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
476 {
477         struct rfkill *rfkill = to_rfkill(dev);
478         int error;
479
480         error = add_uevent_var(env, "RFKILL_NAME=%s", rfkill->name);
481         if (error)
482                 return error;
483         error = add_uevent_var(env, "RFKILL_TYPE=%s",
484                                 rfkill_get_type_str(rfkill->type));
485         if (error)
486                 return error;
487         error = add_uevent_var(env, "RFKILL_STATE=%d", rfkill->state);
488         return error;
489 }
490
491 static struct class rfkill_class = {
492         .name           = "rfkill",
493         .dev_release    = rfkill_release,
494         .dev_attrs      = rfkill_dev_attrs,
495         .suspend        = rfkill_suspend,
496         .resume         = rfkill_resume,
497         .dev_uevent     = rfkill_dev_uevent,
498 };
499
500 static int rfkill_add_switch(struct rfkill *rfkill)
501 {
502         int error;
503
504         mutex_lock(&rfkill_mutex);
505
506         error = rfkill_toggle_radio(rfkill, rfkill_states[rfkill->type], 0);
507         if (!error)
508                 list_add_tail(&rfkill->node, &rfkill_list);
509
510         mutex_unlock(&rfkill_mutex);
511
512         return error;
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);