net/wimax/op-rfkill.c

   1 /*
   2  * Linux WiMAX
   3  * RF-kill framework integration
   4  *
   5  *
   6  * Copyright (C) 2008 Intel Corporation <linux-wimax@intel.com>
   7  * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License version
  11  * 2 as published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  21  * 02110-1301, USA.
  22  *
  23  *
  24  * This integrates into the Linux Kernel rfkill susbystem so that the
  25  * drivers just have to do the bare minimal work, which is providing a
  26  * method to set the software RF-Kill switch and to report changes in
  27  * the software and hardware switch status.
  28  *
  29  * A non-polled generic rfkill device is embedded into the WiMAX
  30  * subsystem's representation of a device.
  31  *
  32  * FIXME: Need polled support? Let drivers provide a poll routine
  33  *        and hand it to rfkill ops then?
  34  *
  35  * All device drivers have to do is after wimax_dev_init(), call
  36  * wimax_report_rfkill_hw() and wimax_report_rfkill_sw() to update
  37  * initial state and then every time it changes. See wimax.h:struct
  38  * wimax_dev for more information.
  39  *
  40  * ROADMAP
  41  *
  42  * wimax_gnl_doit_rfkill()      User space calling wimax_rfkill()
  43  *   wimax_rfkill()             Kernel calling wimax_rfkill()
  44  *     __wimax_rf_toggle_radio()
  45  *
  46  * wimax_rfkill_set_radio_block()  RF-Kill subsystem calling
  47  *   __wimax_rf_toggle_radio()
  48  *
  49  * __wimax_rf_toggle_radio()
  50  *   wimax_dev->op_rfkill_sw_toggle() Driver backend
  51  *   __wimax_state_change()
  52  *
  53  * wimax_report_rfkill_sw()     Driver reports state change
  54  *   __wimax_state_change()
  55  *
  56  * wimax_report_rfkill_hw()     Driver reports state change
  57  *   __wimax_state_change()
  58  *
  59  * wimax_rfkill_add()           Initialize/shutdown rfkill support
  60  * wimax_rfkill_rm()            [called by wimax_dev_add/rm()]
  61  */
  62
  63 #include <net/wimax.h>
  64 #include <net/genetlink.h>
  65 #include <linux/wimax.h>
  66 #include <linux/security.h>
  67 #include <linux/rfkill.h>
  68 #include <linux/export.h>
  69 #include "wimax-internal.h"
  70
  71 #define D_SUBMODULE op_rfkill
  72 #include "debug-levels.h"
  73
  74 /**
  75  * wimax_report_rfkill_hw - Reports changes in the hardware RF switch
  76  *
  77  * @wimax_dev: WiMAX device descriptor
  78  *
  79  * @state: New state of the RF Kill switch. %WIMAX_RF_ON radio on,
  80  *     %WIMAX_RF_OFF radio off.
  81  *
  82  * When the device detects a change in the state of thehardware RF
  83  * switch, it must call this function to let the WiMAX kernel stack
  84  * know that the state has changed so it can be properly propagated.
  85  *
  86  * The WiMAX stack caches the state (the driver doesn't need to). As
  87  * well, as the change is propagated it will come back as a request to
  88  * change the software state to mirror the hardware state.
  89  *
  90  * If the device doesn't have a hardware kill switch, just report
  91  * it on initialization as always on (%WIMAX_RF_ON, radio on).
  92  */
  93 void wimax_report_rfkill_hw(struct wimax_dev *wimax_dev,
  94                             enum wimax_rf_state state)
  95 {
  96         int result;
  97         struct device *dev = wimax_dev_to_dev(wimax_dev);
  98         enum wimax_st wimax_state;
  99
 100         d_fnstart(3, dev, "(wimax_dev %p state %u)\n", wimax_dev, state);
 101         BUG_ON(state == WIMAX_RF_QUERY);
 102         BUG_ON(state != WIMAX_RF_ON && state != WIMAX_RF_OFF);
 103
 104         mutex_lock(&wimax_dev->mutex);
 105         result = wimax_dev_is_ready(wimax_dev);
 106         if (result < 0)
 107                 goto error_not_ready;
 108
 109         if (state != wimax_dev->rf_hw) {
 110                 wimax_dev->rf_hw = state;
 111                 if (wimax_dev->rf_hw == WIMAX_RF_ON &&
 112                     wimax_dev->rf_sw == WIMAX_RF_ON)
 113                         wimax_state = WIMAX_ST_READY;
 114                 else
 115                         wimax_state = WIMAX_ST_RADIO_OFF;
 116
 117                 result = rfkill_set_hw_state(wimax_dev->rfkill,
 118                                              state == WIMAX_RF_OFF);
 119
 120                 __wimax_state_change(wimax_dev, wimax_state);
 121         }
 122 error_not_ready:
 123         mutex_unlock(&wimax_dev->mutex);
 124         d_fnend(3, dev, "(wimax_dev %p state %u) = void [%d]\n",
 125                 wimax_dev, state, result);
 126 }
 127 EXPORT_SYMBOL_GPL(wimax_report_rfkill_hw);
 128
 129
 130 /**
 131  * wimax_report_rfkill_sw - Reports changes in the software RF switch
 132  *
 133  * @wimax_dev: WiMAX device descriptor
 134  *
 135  * @state: New state of the RF kill switch. %WIMAX_RF_ON radio on,
 136  *     %WIMAX_RF_OFF radio off.
 137  *
 138  * Reports changes in the software RF switch state to the WiMAX stack.
 139  *
 140  * The main use is during initialization, so the driver can query the
 141  * device for its current software radio kill switch state and feed it
 142  * to the system.
 143  *
 144  * On the side, the device does not change the software state by
 145  * itself. In practice, this can happen, as the device might decide to
 146  * switch (in software) the radio off for different reasons.
 147  */
 148 void wimax_report_rfkill_sw(struct wimax_dev *wimax_dev,
 149                             enum wimax_rf_state state)
 150 {
 151         int result;
 152         struct device *dev = wimax_dev_to_dev(wimax_dev);
 153         enum wimax_st wimax_state;
 154
 155         d_fnstart(3, dev, "(wimax_dev %p state %u)\n", wimax_dev, state);
 156         BUG_ON(state == WIMAX_RF_QUERY);
 157         BUG_ON(state != WIMAX_RF_ON && state != WIMAX_RF_OFF);
 158
 159         mutex_lock(&wimax_dev->mutex);
 160         result = wimax_dev_is_ready(wimax_dev);
 161         if (result < 0)
 162                 goto error_not_ready;
 163
 164         if (state != wimax_dev->rf_sw) {
 165                 wimax_dev->rf_sw = state;
 166                 if (wimax_dev->rf_hw == WIMAX_RF_ON &&
 167                     wimax_dev->rf_sw == WIMAX_RF_ON)
 168                         wimax_state = WIMAX_ST_READY;
 169                 else
 170                         wimax_state = WIMAX_ST_RADIO_OFF;
 171                 __wimax_state_change(wimax_dev, wimax_state);
 172                 rfkill_set_sw_state(wimax_dev->rfkill, state == WIMAX_RF_OFF);
 173         }
 174 error_not_ready:
 175         mutex_unlock(&wimax_dev->mutex);
 176         d_fnend(3, dev, "(wimax_dev %p state %u) = void [%d]\n",
 177                 wimax_dev, state, result);
 178 }
 179 EXPORT_SYMBOL_GPL(wimax_report_rfkill_sw);
 180
 181
 182 /*
 183  * Callback for the RF Kill toggle operation
 184  *
 185  * This function is called by:
 186  *
 187  * - The rfkill subsystem when the RF-Kill key is pressed in the
 188  *   hardware and the driver notifies through
 189  *   wimax_report_rfkill_hw(). The rfkill subsystem ends up calling back
 190  *   here so the software RF Kill switch state is changed to reflect
 191  *   the hardware switch state.
 192  *
 193  * - When the user sets the state through sysfs' rfkill/state file
 194  *
 195  * - When the user calls wimax_rfkill().
 196  *
 197  * This call blocks!
 198  *
 199  * WARNING! When we call rfkill_unregister(), this will be called with
 200  * state 0!
 201  *
 202  * WARNING: wimax_dev must be locked
 203  */
 204 static
 205 int __wimax_rf_toggle_radio(struct wimax_dev *wimax_dev,
 206                             enum wimax_rf_state state)
 207 {
 208         int result = 0;
 209         struct device *dev = wimax_dev_to_dev(wimax_dev);
 210         enum wimax_st wimax_state;
 211
 212         might_sleep();
 213         d_fnstart(3, dev, "(wimax_dev %p state %u)\n", wimax_dev, state);
 214         if (wimax_dev->rf_sw == state)
 215                 goto out_no_change;
 216         if (wimax_dev->op_rfkill_sw_toggle != NULL)
 217                 result = wimax_dev->op_rfkill_sw_toggle(wimax_dev, state);
 218         else if (state == WIMAX_RF_OFF) /* No op? can't turn off */
 219                 result = -ENXIO;
 220         else                            /* No op? can turn on */
 221                 result = 0;             /* should never happen tho */
 222         if (result >= 0) {
 223                 result = 0;
 224                 wimax_dev->rf_sw = state;
 225                 wimax_state = state == WIMAX_RF_ON ?
 226                         WIMAX_ST_READY : WIMAX_ST_RADIO_OFF;
 227                 __wimax_state_change(wimax_dev, wimax_state);
 228         }
 229 out_no_change:
 230         d_fnend(3, dev, "(wimax_dev %p state %u) = %d\n",
 231                 wimax_dev, state, result);
 232         return result;
 233 }
 234
 235
 236 /*
 237  * Translate from rfkill state to wimax state
 238  *
 239  * NOTE: Special state handling rules here
 240  *
 241  *     Just pretend the call didn't happen if we are in a state where
 242  *     we know for sure it cannot be handled (WIMAX_ST_DOWN or
 243  *     __WIMAX_ST_QUIESCING). rfkill() needs it to register and
 244  *     unregister, as it will run this path.
 245  *
 246  * NOTE: This call will block until the operation is completed.
 247  */
 248 static int wimax_rfkill_set_radio_block(void *data, bool blocked)
 249 {
 250         int result;
 251         struct wimax_dev *wimax_dev = data;
 252         struct device *dev = wimax_dev_to_dev(wimax_dev);
 253         enum wimax_rf_state rf_state;
 254
 255         d_fnstart(3, dev, "(wimax_dev %p blocked %u)\n", wimax_dev, blocked);
 256         rf_state = WIMAX_RF_ON;
 257         if (blocked)
 258                 rf_state = WIMAX_RF_OFF;
 259         mutex_lock(&wimax_dev->mutex);
 260         if (wimax_dev->state <= __WIMAX_ST_QUIESCING)
 261                 result = 0;
 262         else
 263                 result = __wimax_rf_toggle_radio(wimax_dev, rf_state);
 264         mutex_unlock(&wimax_dev->mutex);
 265         d_fnend(3, dev, "(wimax_dev %p blocked %u) = %d\n",
 266                 wimax_dev, blocked, result);
 267         return result;
 268 }
 269
 270 static const struct rfkill_ops wimax_rfkill_ops = {
 271         .set_block = wimax_rfkill_set_radio_block,
 272 };
 273
 274 /**
 275  * wimax_rfkill - Set the software RF switch state for a WiMAX device
 276  *
 277  * @wimax_dev: WiMAX device descriptor
 278  *
 279  * @state: New RF state.
 280  *
 281  * Returns:
 282  *
 283  * >= 0 toggle state if ok, < 0 errno code on error. The toggle state
 284  * is returned as a bitmap, bit 0 being the hardware RF state, bit 1
 285  * the software RF state.
 286  *
 287  * 0 means disabled (%WIMAX_RF_ON, radio on), 1 means enabled radio
 288  * off (%WIMAX_RF_OFF).
 289  *
 290  * Description:
 291  *
 292  * Called by the user when he wants to request the WiMAX radio to be
 293  * switched on (%WIMAX_RF_ON) or off (%WIMAX_RF_OFF). With
 294  * %WIMAX_RF_QUERY, just the current state is returned.
 295  *
 296  * NOTE:
 297  *
 298  * This call will block until the operation is complete.
 299  */
 300 int wimax_rfkill(struct wimax_dev *wimax_dev, enum wimax_rf_state state)
 301 {
 302         int result;
 303         struct device *dev = wimax_dev_to_dev(wimax_dev);
 304
 305         d_fnstart(3, dev, "(wimax_dev %p state %u)\n", wimax_dev, state);
 306         mutex_lock(&wimax_dev->mutex);
 307         result = wimax_dev_is_ready(wimax_dev);
 308         if (result < 0) {
 309                 /* While initializing, < 1.4.3 wimax-tools versions use
 310                  * this call to check if the device is a valid WiMAX
 311                  * device; so we allow it to proceed always,
 312                  * considering the radios are all off. */
 313                 if (result == -ENOMEDIUM && state == WIMAX_RF_QUERY)
 314                         result = WIMAX_RF_OFF << 1 | WIMAX_RF_OFF;
 315                 goto error_not_ready;
 316         }
 317         switch (state) {
 318         case WIMAX_RF_ON:
 319         case WIMAX_RF_OFF:
 320                 result = __wimax_rf_toggle_radio(wimax_dev, state);
 321                 if (result < 0)
 322                         goto error;
 323                 rfkill_set_sw_state(wimax_dev->rfkill, state == WIMAX_RF_OFF);
 324                 break;
 325         case WIMAX_RF_QUERY:
 326                 break;
 327         default:
 328                 result = -EINVAL;
 329                 goto error;
 330         }
 331         result = wimax_dev->rf_sw << 1 | wimax_dev->rf_hw;
 332 error:
 333 error_not_ready:
 334         mutex_unlock(&wimax_dev->mutex);
 335         d_fnend(3, dev, "(wimax_dev %p state %u) = %d\n",
 336                 wimax_dev, state, result);
 337         return result;
 338 }
 339 EXPORT_SYMBOL(wimax_rfkill);
 340
 341
 342 /*
 343  * Register a new WiMAX device's RF Kill support
 344  *
 345  * WARNING: wimax_dev->mutex must be unlocked
 346  */
 347 int wimax_rfkill_add(struct wimax_dev *wimax_dev)
 348 {
 349         int result;
 350         struct rfkill *rfkill;
 351         struct device *dev = wimax_dev_to_dev(wimax_dev);
 352
 353         d_fnstart(3, dev, "(wimax_dev %p)\n", wimax_dev);
 354         /* Initialize RF Kill */
 355         result = -ENOMEM;
 356         rfkill = rfkill_alloc(wimax_dev->name, dev, RFKILL_TYPE_WIMAX,
 357                               &wimax_rfkill_ops, wimax_dev);
 358         if (rfkill == NULL)
 359                 goto error_rfkill_allocate;
 360
 361         d_printf(1, dev, "rfkill %p\n", rfkill);
 362
 363         wimax_dev->rfkill = rfkill;
 364
 365         rfkill_init_sw_state(rfkill, 1);
 366         result = rfkill_register(wimax_dev->rfkill);
 367         if (result < 0)
 368                 goto error_rfkill_register;
 369
 370         /* If there is no SW toggle op, SW RFKill is always on */
 371         if (wimax_dev->op_rfkill_sw_toggle == NULL)
 372                 wimax_dev->rf_sw = WIMAX_RF_ON;
 373
 374         d_fnend(3, dev, "(wimax_dev %p) = 0\n", wimax_dev);
 375         return 0;
 376
 377 error_rfkill_register:
 378         rfkill_destroy(wimax_dev->rfkill);
 379 error_rfkill_allocate:
 380         d_fnend(3, dev, "(wimax_dev %p) = %d\n", wimax_dev, result);
 381         return result;
 382 }
 383
 384
 385 /*
 386  * Deregister a WiMAX device's RF Kill support
 387  *
 388  * Ick, we can't call rfkill_free() after rfkill_unregister()...oh
 389  * well.
 390  *
 391  * WARNING: wimax_dev->mutex must be unlocked
 392  */
 393 void wimax_rfkill_rm(struct wimax_dev *wimax_dev)
 394 {
 395         struct device *dev = wimax_dev_to_dev(wimax_dev);
 396         d_fnstart(3, dev, "(wimax_dev %p)\n", wimax_dev);
 397         rfkill_unregister(wimax_dev->rfkill);
 398         rfkill_destroy(wimax_dev->rfkill);
 399         d_fnend(3, dev, "(wimax_dev %p)\n", wimax_dev);
 400 }
 401
 402
 403 /*
 404  * Exporting to user space over generic netlink
 405  *
 406  * Parse the rfkill command from user space, return a combination
 407  * value that describe the states of the different toggles.
 408  *
 409  * Only one attribute: the new state requested (on, off or no change,
 410  * just query).
 411  */
 412
 413 int wimax_gnl_doit_rfkill(struct sk_buff *skb, struct genl_info *info)
 414 {
 415         int result, ifindex;
 416         struct wimax_dev *wimax_dev;
 417         struct device *dev;
 418         enum wimax_rf_state new_state;
 419
 420         d_fnstart(3, NULL, "(skb %p info %p)\n", skb, info);
 421         result = -ENODEV;
 422         if (info->attrs[WIMAX_GNL_RFKILL_IFIDX] == NULL) {
 423                 pr_err("WIMAX_GNL_OP_RFKILL: can't find IFIDX attribute\n");
 424                 goto error_no_wimax_dev;
 425         }
 426         ifindex = nla_get_u32(info->attrs[WIMAX_GNL_RFKILL_IFIDX]);
 427         wimax_dev = wimax_dev_get_by_genl_info(info, ifindex);
 428         if (wimax_dev == NULL)
 429                 goto error_no_wimax_dev;
 430         dev = wimax_dev_to_dev(wimax_dev);
 431         result = -EINVAL;
 432         if (info->attrs[WIMAX_GNL_RFKILL_STATE] == NULL) {
 433                 dev_err(dev, "WIMAX_GNL_RFKILL: can't find RFKILL_STATE "
 434                         "attribute\n");
 435                 goto error_no_pid;
 436         }
 437         new_state = nla_get_u32(info->attrs[WIMAX_GNL_RFKILL_STATE]);
 438
 439         /* Execute the operation and send the result back to user space */
 440         result = wimax_rfkill(wimax_dev, new_state);
 441 error_no_pid:
 442         dev_put(wimax_dev->net_dev);
 443 error_no_wimax_dev:
 444         d_fnend(3, NULL, "(skb %p info %p) = %d\n", skb, info, result);
 445         return result;
 446 }