net/rfkill/rfkill.c

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