net/wimax/op-rfkill.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Linux WiMAX
   4  * RF-kill framework integration
   5  *
   6  * Copyright (C) 2008 Intel Corporation <linux-wimax@intel.com>
   7  * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
   8  *
   9  * This integrates into the Linux Kernel rfkill susbystem so that the
  10  * drivers just have to do the bare minimal work, which is providing a
  11  * method to set the software RF-Kill switch and to report changes in
  12  * the software and hardware switch status.
  13  *
  14  * A non-polled generic rfkill device is embedded into the WiMAX
  15  * subsystem's representation of a device.
  16  *
  17  * FIXME: Need polled support? Let drivers provide a poll routine
  18  *        and hand it to rfkill ops then?
  19  *
  20  * All device drivers have to do is after wimax_dev_init(), call
  21  * wimax_report_rfkill_hw() and wimax_report_rfkill_sw() to update
  22  * initial state and then every time it changes. See wimax.h:struct
  23  * wimax_dev for more information.
  24  *
  25  * ROADMAP
  26  *
  27  * wimax_gnl_doit_rfkill()      User space calling wimax_rfkill()
  28  *   wimax_rfkill()             Kernel calling wimax_rfkill()
  29  *     __wimax_rf_toggle_radio()
  30  *
  31  * wimax_rfkill_set_radio_block()  RF-Kill subsystem calling
  32  *   __wimax_rf_toggle_radio()
  33  *
  34  * __wimax_rf_toggle_radio()
  35  *   wimax_dev->op_rfkill_sw_toggle() Driver backend
  36  *   __wimax_state_change()
  37  *
  38  * wimax_report_rfkill_sw()     Driver reports state change
  39  *   __wimax_state_change()
  40  *
  41  * wimax_report_rfkill_hw()     Driver reports state change
  42  *   __wimax_state_change()
  43  *
  44  * wimax_rfkill_add()           Initialize/shutdown rfkill support
  45  * wimax_rfkill_rm()            [called by wimax_dev_add/rm()]
  46  */
  47
  48 #include <net/wimax.h>
  49 #include <net/genetlink.h>
  50 #include <linux/wimax.h>
  51 #include <linux/security.h>
  52 #include <linux/rfkill.h>
  53 #include <linux/export.h>
  54 #include "wimax-internal.h"
  55
  56 #define D_SUBMODULE op_rfkill
  57 #include "debug-levels.h"
  58
  59 /**
  60  * wimax_report_rfkill_hw - Reports changes in the hardware RF switch
  61  *
  62  * @wimax_dev: WiMAX device descriptor
  63  *
  64  * @state: New state of the RF Kill switch. %WIMAX_RF_ON radio on,
  65  *     %WIMAX_RF_OFF radio off.
  66  *
  67  * When the device detects a change in the state of thehardware RF
  68  * switch, it must call this function to let the WiMAX kernel stack
  69  * know that the state has changed so it can be properly propagated.
  70  *
  71  * The WiMAX stack caches the state (the driver doesn't need to). As
  72  * well, as the change is propagated it will come back as a request to
  73  * change the software state to mirror the hardware state.
  74  *
  75  * If the device doesn't have a hardware kill switch, just report
  76  * it on initialization as always on (%WIMAX_RF_ON, radio on).
  77  */
  78 void wimax_report_rfkill_hw(struct wimax_dev *wimax_dev,
  79                             enum wimax_rf_state state)
  80 {
  81         int result;
  82         struct device *dev = wimax_dev_to_dev(wimax_dev);
  83         enum wimax_st wimax_state;
  84
  85         d_fnstart(3, dev, "(wimax_dev %p state %u)\n", wimax_dev, state);
  86         BUG_ON(state == WIMAX_RF_QUERY);
  87         BUG_ON(state != WIMAX_RF_ON && state != WIMAX_RF_OFF);
  88
  89         mutex_lock(&wimax_dev->mutex);
  90         result = wimax_dev_is_ready(wimax_dev);
  91         if (result < 0)
  92                 goto error_not_ready;
  93
  94         if (state != wimax_dev->rf_hw) {
  95                 wimax_dev->rf_hw = state;
  96                 if (wimax_dev->rf_hw == WIMAX_RF_ON &&
  97                     wimax_dev->rf_sw == WIMAX_RF_ON)
  98                         wimax_state = WIMAX_ST_READY;
  99                 else
 100                         wimax_state = WIMAX_ST_RADIO_OFF;
 101
 102                 result = rfkill_set_hw_state(wimax_dev->rfkill,
 103                                              state == WIMAX_RF_OFF);
 104
 105                 __wimax_state_change(wimax_dev, wimax_state);
 106         }
 107 error_not_ready:
 108         mutex_unlock(&wimax_dev->mutex);
 109         d_fnend(3, dev, "(wimax_dev %p state %u) = void [%d]\n",
 110                 wimax_dev, state, result);
 111 }
 112 EXPORT_SYMBOL_GPL(wimax_report_rfkill_hw);
 113
 114
 115 /**
 116  * wimax_report_rfkill_sw - Reports changes in the software RF switch
 117  *
 118  * @wimax_dev: WiMAX device descriptor
 119  *
 120  * @state: New state of the RF kill switch. %WIMAX_RF_ON radio on,
 121  *     %WIMAX_RF_OFF radio off.
 122  *
 123  * Reports changes in the software RF switch state to the WiMAX stack.
 124  *
 125  * The main use is during initialization, so the driver can query the
 126  * device for its current software radio kill switch state and feed it
 127  * to the system.
 128  *
 129  * On the side, the device does not change the software state by
 130  * itself. In practice, this can happen, as the device might decide to
 131  * switch (in software) the radio off for different reasons.
 132  */
 133 void wimax_report_rfkill_sw(struct wimax_dev *wimax_dev,
 134                             enum wimax_rf_state state)
 135 {
 136         int result;
 137         struct device *dev = wimax_dev_to_dev(wimax_dev);
 138         enum wimax_st wimax_state;
 139
 140         d_fnstart(3, dev, "(wimax_dev %p state %u)\n", wimax_dev, state);
 141         BUG_ON(state == WIMAX_RF_QUERY);
 142         BUG_ON(state != WIMAX_RF_ON && state != WIMAX_RF_OFF);
 143
 144         mutex_lock(&wimax_dev->mutex);
 145         result = wimax_dev_is_ready(wimax_dev);
 146         if (result < 0)
 147                 goto error_not_ready;
 148
 149         if (state != wimax_dev->rf_sw) {
 150                 wimax_dev->rf_sw = state;
 151                 if (wimax_dev->rf_hw == WIMAX_RF_ON &&
 152                     wimax_dev->rf_sw == WIMAX_RF_ON)
 153                         wimax_state = WIMAX_ST_READY;
 154                 else
 155                         wimax_state = WIMAX_ST_RADIO_OFF;
 156                 __wimax_state_change(wimax_dev, wimax_state);
 157                 rfkill_set_sw_state(wimax_dev->rfkill, state == WIMAX_RF_OFF);
 158         }
 159 error_not_ready:
 160         mutex_unlock(&wimax_dev->mutex);
 161         d_fnend(3, dev, "(wimax_dev %p state %u) = void [%d]\n",
 162                 wimax_dev, state, result);
 163 }
 164 EXPORT_SYMBOL_GPL(wimax_report_rfkill_sw);
 165
 166
 167 /*
 168  * Callback for the RF Kill toggle operation
 169  *
 170  * This function is called by:
 171  *
 172  * - The rfkill subsystem when the RF-Kill key is pressed in the
 173  *   hardware and the driver notifies through
 174  *   wimax_report_rfkill_hw(). The rfkill subsystem ends up calling back
 175  *   here so the software RF Kill switch state is changed to reflect
 176  *   the hardware switch state.
 177  *
 178  * - When the user sets the state through sysfs' rfkill/state file
 179  *
 180  * - When the user calls wimax_rfkill().
 181  *
 182  * This call blocks!
 183  *
 184  * WARNING! When we call rfkill_unregister(), this will be called with
 185  * state 0!
 186  *
 187  * WARNING: wimax_dev must be locked
 188  */
 189 static
 190 int __wimax_rf_toggle_radio(struct wimax_dev *wimax_dev,
 191                             enum wimax_rf_state state)
 192 {
 193         int result = 0;
 194         struct device *dev = wimax_dev_to_dev(wimax_dev);
 195         enum wimax_st wimax_state;
 196
 197         might_sleep();
 198         d_fnstart(3, dev, "(wimax_dev %p state %u)\n", wimax_dev, state);
 199         if (wimax_dev->rf_sw == state)
 200                 goto out_no_change;
 201         if (wimax_dev->op_rfkill_sw_toggle != NULL)
 202                 result = wimax_dev->op_rfkill_sw_toggle(wimax_dev, state);
 203         else if (state == WIMAX_RF_OFF) /* No op? can't turn off */
 204                 result = -ENXIO;
 205         else                            /* No op? can turn on */
 206                 result = 0;             /* should never happen tho */
 207         if (result >= 0) {
 208                 result = 0;
 209                 wimax_dev->rf_sw = state;
 210                 wimax_state = state == WIMAX_RF_ON ?
 211                         WIMAX_ST_READY : WIMAX_ST_RADIO_OFF;
 212                 __wimax_state_change(wimax_dev, wimax_state);
 213         }
 214 out_no_change:
 215         d_fnend(3, dev, "(wimax_dev %p state %u) = %d\n",
 216                 wimax_dev, state, result);
 217         return result;
 218 }
 219
 220
 221 /*
 222  * Translate from rfkill state to wimax state
 223  *
 224  * NOTE: Special state handling rules here
 225  *
 226  *     Just pretend the call didn't happen if we are in a state where
 227  *     we know for sure it cannot be handled (WIMAX_ST_DOWN or
 228  *     __WIMAX_ST_QUIESCING). rfkill() needs it to register and
 229  *     unregister, as it will run this path.
 230  *
 231  * NOTE: This call will block until the operation is completed.
 232  */
 233 static int wimax_rfkill_set_radio_block(void *data, bool blocked)
 234 {
 235         int result;
 236         struct wimax_dev *wimax_dev = data;
 237         struct device *dev = wimax_dev_to_dev(wimax_dev);
 238         enum wimax_rf_state rf_state;
 239
 240         d_fnstart(3, dev, "(wimax_dev %p blocked %u)\n", wimax_dev, blocked);
 241         rf_state = WIMAX_RF_ON;
 242         if (blocked)
 243                 rf_state = WIMAX_RF_OFF;
 244         mutex_lock(&wimax_dev->mutex);
 245         if (wimax_dev->state <= __WIMAX_ST_QUIESCING)
 246                 result = 0;
 247         else
 248                 result = __wimax_rf_toggle_radio(wimax_dev, rf_state);
 249         mutex_unlock(&wimax_dev->mutex);
 250         d_fnend(3, dev, "(wimax_dev %p blocked %u) = %d\n",
 251                 wimax_dev, blocked, result);
 252         return result;
 253 }
 254
 255 static const struct rfkill_ops wimax_rfkill_ops = {
 256         .set_block = wimax_rfkill_set_radio_block,
 257 };
 258
 259 /**
 260  * wimax_rfkill - Set the software RF switch state for a WiMAX device
 261  *
 262  * @wimax_dev: WiMAX device descriptor
 263  *
 264  * @state: New RF state.
 265  *
 266  * Returns:
 267  *
 268  * >= 0 toggle state if ok, < 0 errno code on error. The toggle state
 269  * is returned as a bitmap, bit 0 being the hardware RF state, bit 1
 270  * the software RF state.
 271  *
 272  * 0 means disabled (%WIMAX_RF_ON, radio on), 1 means enabled radio
 273  * off (%WIMAX_RF_OFF).
 274  *
 275  * Description:
 276  *
 277  * Called by the user when he wants to request the WiMAX radio to be
 278  * switched on (%WIMAX_RF_ON) or off (%WIMAX_RF_OFF). With
 279  * %WIMAX_RF_QUERY, just the current state is returned.
 280  *
 281  * NOTE:
 282  *
 283  * This call will block until the operation is complete.
 284  */
 285 int wimax_rfkill(struct wimax_dev *wimax_dev, enum wimax_rf_state state)
 286 {
 287         int result;
 288         struct device *dev = wimax_dev_to_dev(wimax_dev);
 289
 290         d_fnstart(3, dev, "(wimax_dev %p state %u)\n", wimax_dev, state);
 291         mutex_lock(&wimax_dev->mutex);
 292         result = wimax_dev_is_ready(wimax_dev);
 293         if (result < 0) {
 294                 /* While initializing, < 1.4.3 wimax-tools versions use
 295                  * this call to check if the device is a valid WiMAX
 296                  * device; so we allow it to proceed always,
 297                  * considering the radios are all off. */
 298                 if (result == -ENOMEDIUM && state == WIMAX_RF_QUERY)
 299                         result = WIMAX_RF_OFF << 1 | WIMAX_RF_OFF;
 300                 goto error_not_ready;
 301         }
 302         switch (state) {
 303         case WIMAX_RF_ON:
 304         case WIMAX_RF_OFF:
 305                 result = __wimax_rf_toggle_radio(wimax_dev, state);
 306                 if (result < 0)
 307                         goto error;
 308                 rfkill_set_sw_state(wimax_dev->rfkill, state == WIMAX_RF_OFF);
 309                 break;
 310         case WIMAX_RF_QUERY:
 311                 break;
 312         default:
 313                 result = -EINVAL;
 314                 goto error;
 315         }
 316         result = wimax_dev->rf_sw << 1 | wimax_dev->rf_hw;
 317 error:
 318 error_not_ready:
 319         mutex_unlock(&wimax_dev->mutex);
 320         d_fnend(3, dev, "(wimax_dev %p state %u) = %d\n",
 321                 wimax_dev, state, result);
 322         return result;
 323 }
 324 EXPORT_SYMBOL(wimax_rfkill);
 325
 326
 327 /*
 328  * Register a new WiMAX device's RF Kill support
 329  *
 330  * WARNING: wimax_dev->mutex must be unlocked
 331  */
 332 int wimax_rfkill_add(struct wimax_dev *wimax_dev)
 333 {
 334         int result;
 335         struct rfkill *rfkill;
 336         struct device *dev = wimax_dev_to_dev(wimax_dev);
 337
 338         d_fnstart(3, dev, "(wimax_dev %p)\n", wimax_dev);
 339         /* Initialize RF Kill */
 340         result = -ENOMEM;
 341         rfkill = rfkill_alloc(wimax_dev->name, dev, RFKILL_TYPE_WIMAX,
 342                               &wimax_rfkill_ops, wimax_dev);
 343         if (rfkill == NULL)
 344                 goto error_rfkill_allocate;
 345
 346         d_printf(1, dev, "rfkill %p\n", rfkill);
 347
 348         wimax_dev->rfkill = rfkill;
 349
 350         rfkill_init_sw_state(rfkill, 1);
 351         result = rfkill_register(wimax_dev->rfkill);
 352         if (result < 0)
 353                 goto error_rfkill_register;
 354
 355         /* If there is no SW toggle op, SW RFKill is always on */
 356         if (wimax_dev->op_rfkill_sw_toggle == NULL)
 357                 wimax_dev->rf_sw = WIMAX_RF_ON;
 358
 359         d_fnend(3, dev, "(wimax_dev %p) = 0\n", wimax_dev);
 360         return 0;
 361
 362 error_rfkill_register:
 363         rfkill_destroy(wimax_dev->rfkill);
 364 error_rfkill_allocate:
 365         d_fnend(3, dev, "(wimax_dev %p) = %d\n", wimax_dev, result);
 366         return result;
 367 }
 368
 369
 370 /*
 371  * Deregister a WiMAX device's RF Kill support
 372  *
 373  * Ick, we can't call rfkill_free() after rfkill_unregister()...oh
 374  * well.
 375  *
 376  * WARNING: wimax_dev->mutex must be unlocked
 377  */
 378 void wimax_rfkill_rm(struct wimax_dev *wimax_dev)
 379 {
 380         struct device *dev = wimax_dev_to_dev(wimax_dev);
 381         d_fnstart(3, dev, "(wimax_dev %p)\n", wimax_dev);
 382         rfkill_unregister(wimax_dev->rfkill);
 383         rfkill_destroy(wimax_dev->rfkill);
 384         d_fnend(3, dev, "(wimax_dev %p)\n", wimax_dev);
 385 }
 386
 387
 388 /*
 389  * Exporting to user space over generic netlink
 390  *
 391  * Parse the rfkill command from user space, return a combination
 392  * value that describe the states of the different toggles.
 393  *
 394  * Only one attribute: the new state requested (on, off or no change,
 395  * just query).
 396  */
 397
 398 int wimax_gnl_doit_rfkill(struct sk_buff *skb, struct genl_info *info)
 399 {
 400         int result, ifindex;
 401         struct wimax_dev *wimax_dev;
 402         struct device *dev;
 403         enum wimax_rf_state new_state;
 404
 405         d_fnstart(3, NULL, "(skb %p info %p)\n", skb, info);
 406         result = -ENODEV;
 407         if (info->attrs[WIMAX_GNL_RFKILL_IFIDX] == NULL) {
 408                 pr_err("WIMAX_GNL_OP_RFKILL: can't find IFIDX attribute\n");
 409                 goto error_no_wimax_dev;
 410         }
 411         ifindex = nla_get_u32(info->attrs[WIMAX_GNL_RFKILL_IFIDX]);
 412         wimax_dev = wimax_dev_get_by_genl_info(info, ifindex);
 413         if (wimax_dev == NULL)
 414                 goto error_no_wimax_dev;
 415         dev = wimax_dev_to_dev(wimax_dev);
 416         result = -EINVAL;
 417         if (info->attrs[WIMAX_GNL_RFKILL_STATE] == NULL) {
 418                 dev_err(dev, "WIMAX_GNL_RFKILL: can't find RFKILL_STATE "
 419                         "attribute\n");
 420                 goto error_no_pid;
 421         }
 422         new_state = nla_get_u32(info->attrs[WIMAX_GNL_RFKILL_STATE]);
 423
 424         /* Execute the operation and send the result back to user space */
 425         result = wimax_rfkill(wimax_dev, new_state);
 426 error_no_pid:
 427         dev_put(wimax_dev->net_dev);
 428 error_no_wimax_dev:
 429         d_fnend(3, NULL, "(skb %p info %p) = %d\n", skb, info, result);
 430         return result;
 431 }