SAFE public projects git trees. - safe/jmp/linux-2.6/blob - drivers/net/wireless/iwlwifi/iwl-rx.c

   1 /******************************************************************************
   2  *
   3  * Copyright(c) 2003 - 2010 Intel Corporation. All rights reserved.
   4  *
   5  * Portions of this file are derived from the ipw3945 project, as well
   6  * as portions of the ieee80211 subsystem header files.
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of version 2 of the GNU General Public License as
  10  * published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15  * more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along with
  18  * this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110, USA
  20  *
  21  * The full GNU General Public License is included in this distribution in the
  22  * file called LICENSE.
  23  *
  24  * Contact Information:
  25  *  Intel Linux Wireless <ilw@linux.intel.com>
  26  * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
  27  *
  28  *****************************************************************************/
  29
  30 #include <linux/etherdevice.h>
  31 #include <net/mac80211.h>
  32 #include <asm/unaligned.h>
  33 #include "iwl-eeprom.h"
  34 #include "iwl-dev.h"
  35 #include "iwl-core.h"
  36 #include "iwl-sta.h"
  37 #include "iwl-io.h"
  38 #include "iwl-calib.h"
  39 #include "iwl-helpers.h"
  40 /************************** RX-FUNCTIONS ****************************/
  41 /*
  42  * Rx theory of operation
  43  *
  44  * Driver allocates a circular buffer of Receive Buffer Descriptors (RBDs),
  45  * each of which point to Receive Buffers to be filled by the NIC.  These get
  46  * used not only for Rx frames, but for any command response or notification
  47  * from the NIC.  The driver and NIC manage the Rx buffers by means
  48  * of indexes into the circular buffer.
  49  *
  50  * Rx Queue Indexes
  51  * The host/firmware share two index registers for managing the Rx buffers.
  52  *
  53  * The READ index maps to the first position that the firmware may be writing
  54  * to -- the driver can read up to (but not including) this position and get
  55  * good data.
  56  * The READ index is managed by the firmware once the card is enabled.
  57  *
  58  * The WRITE index maps to the last position the driver has read from -- the
  59  * position preceding WRITE is the last slot the firmware can place a packet.
  60  *
  61  * The queue is empty (no good data) if WRITE = READ - 1, and is full if
  62  * WRITE = READ.
  63  *
  64  * During initialization, the host sets up the READ queue position to the first
  65  * INDEX position, and WRITE to the last (READ - 1 wrapped)
  66  *
  67  * When the firmware places a packet in a buffer, it will advance the READ index
  68  * and fire the RX interrupt.  The driver can then query the READ index and
  69  * process as many packets as possible, moving the WRITE index forward as it
  70  * resets the Rx queue buffers with new memory.
  71  *
  72  * The management in the driver is as follows:
  73  * + A list of pre-allocated SKBs is stored in iwl->rxq->rx_free.  When
  74  *   iwl->rxq->free_count drops to or below RX_LOW_WATERMARK, work is scheduled
  75  *   to replenish the iwl->rxq->rx_free.
  76  * + In iwl_rx_replenish (scheduled) if 'processed' != 'read' then the
  77  *   iwl->rxq is replenished and the READ INDEX is updated (updating the
  78  *   'processed' and 'read' driver indexes as well)
  79  * + A received packet is processed and handed to the kernel network stack,
  80  *   detached from the iwl->rxq.  The driver 'processed' index is updated.
  81  * + The Host/Firmware iwl->rxq is replenished at tasklet time from the rx_free
  82  *   list. If there are no allocated buffers in iwl->rxq->rx_free, the READ
  83  *   INDEX is not incremented and iwl->status(RX_STALLED) is set.  If there
  84  *   were enough free buffers and RX_STALLED is set it is cleared.
  85  *
  86  *
  87  * Driver sequence:
  88  *
  89  * iwl_rx_queue_alloc()   Allocates rx_free
  90  * iwl_rx_replenish()     Replenishes rx_free list from rx_used, and calls
  91  *                            iwl_rx_queue_restock
  92  * iwl_rx_queue_restock() Moves available buffers from rx_free into Rx
  93  *                            queue, updates firmware pointers, and updates
  94  *                            the WRITE index.  If insufficient rx_free buffers
  95  *                            are available, schedules iwl_rx_replenish
  96  *
  97  * -- enable interrupts --
  98  * ISR - iwl_rx()         Detach iwl_rx_mem_buffers from pool up to the
  99  *                            READ INDEX, detaching the SKB from the pool.
 100  *                            Moves the packet buffer from queue to rx_used.
 101  *                            Calls iwl_rx_queue_restock to refill any empty
 102  *                            slots.
 103  * ...
 104  *
 105  */
 106
 107 /**
 108  * iwl_rx_queue_space - Return number of free slots available in queue.
 109  */
 110 int iwl_rx_queue_space(const struct iwl_rx_queue *q)
 111 {
 112         int s = q->read - q->write;
 113         if (s <= 0)
 114                 s += RX_QUEUE_SIZE;
 115         /* keep some buffer to not confuse full and empty queue */
 116         s -= 2;
 117         if (s < 0)
 118                 s = 0;
 119         return s;
 120 }
 121 EXPORT_SYMBOL(iwl_rx_queue_space);
 122
 123 /**
 124  * iwl_rx_queue_update_write_ptr - Update the write pointer for the RX queue
 125  */
 126 void iwl_rx_queue_update_write_ptr(struct iwl_priv *priv, struct iwl_rx_queue *q)
 127 {
 128         unsigned long flags;
 129         u32 rx_wrt_ptr_reg = priv->hw_params.rx_wrt_ptr_reg;
 130         u32 reg;
 131
 132         spin_lock_irqsave(&q->lock, flags);
 133
 134         if (q->need_update == 0)
 135                 goto exit_unlock;
 136
 137         /* If power-saving is in use, make sure device is awake */
 138         if (test_bit(STATUS_POWER_PMI, &priv->status)) {
 139                 reg = iwl_read32(priv, CSR_UCODE_DRV_GP1);
 140
 141                 if (reg & CSR_UCODE_DRV_GP1_BIT_MAC_SLEEP) {
 142                         IWL_DEBUG_INFO(priv, "Rx queue requesting wakeup, GP1 = 0x%x\n",
 143                                       reg);
 144                         iwl_set_bit(priv, CSR_GP_CNTRL,
 145                                     CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ);
 146                         goto exit_unlock;
 147                 }
 148
 149                 q->write_actual = (q->write & ~0x7);
 150                 iwl_write_direct32(priv, rx_wrt_ptr_reg, q->write_actual);
 151
 152         /* Else device is assumed to be awake */
 153         } else {
 154                 /* Device expects a multiple of 8 */
 155                 q->write_actual = (q->write & ~0x7);
 156                 iwl_write_direct32(priv, rx_wrt_ptr_reg, q->write_actual);
 157         }
 158
 159         q->need_update = 0;
 160
 161  exit_unlock:
 162         spin_unlock_irqrestore(&q->lock, flags);
 163 }
 164 EXPORT_SYMBOL(iwl_rx_queue_update_write_ptr);
 165
 166 int iwl_rx_queue_alloc(struct iwl_priv *priv)
 167 {
 168         struct iwl_rx_queue *rxq = &priv->rxq;
 169         struct device *dev = &priv->pci_dev->dev;
 170         int i;
 171
 172         spin_lock_init(&rxq->lock);
 173         INIT_LIST_HEAD(&rxq->rx_free);
 174         INIT_LIST_HEAD(&rxq->rx_used);
 175
 176         /* Alloc the circular buffer of Read Buffer Descriptors (RBDs) */
 177         rxq->bd = dma_alloc_coherent(dev, 4 * RX_QUEUE_SIZE, &rxq->dma_addr,
 178                                      GFP_KERNEL);
 179         if (!rxq->bd)
 180                 goto err_bd;
 181
 182         rxq->rb_stts = dma_alloc_coherent(dev, sizeof(struct iwl_rb_status),
 183                                           &rxq->rb_stts_dma, GFP_KERNEL);
 184         if (!rxq->rb_stts)
 185                 goto err_rb;
 186
 187         /* Fill the rx_used queue with _all_ of the Rx buffers */
 188         for (i = 0; i < RX_FREE_BUFFERS + RX_QUEUE_SIZE; i++)
 189                 list_add_tail(&rxq->pool[i].list, &rxq->rx_used);
 190
 191         /* Set us so that we have processed and used all buffers, but have
 192          * not restocked the Rx queue with fresh buffers */
 193         rxq->read = rxq->write = 0;
 194         rxq->write_actual = 0;
 195         rxq->free_count = 0;
 196         rxq->need_update = 0;
 197         return 0;
 198
 199 err_rb:
 200         dma_free_coherent(&priv->pci_dev->dev, 4 * RX_QUEUE_SIZE, rxq->bd,
 201                           rxq->dma_addr);
 202 err_bd:
 203         return -ENOMEM;
 204 }
 205 EXPORT_SYMBOL(iwl_rx_queue_alloc);
 206
 207 void iwl_rx_missed_beacon_notif(struct iwl_priv *priv,
 208                                 struct iwl_rx_mem_buffer *rxb)
 209
 210 {
 211         struct iwl_rx_packet *pkt = rxb_addr(rxb);
 212         struct iwl_missed_beacon_notif *missed_beacon;
 213
 214         missed_beacon = &pkt->u.missed_beacon;
 215         if (le32_to_cpu(missed_beacon->consecutive_missed_beacons) >
 216             priv->missed_beacon_threshold) {
 217                 IWL_DEBUG_CALIB(priv, "missed bcn cnsq %d totl %d rcd %d expctd %d\n",
 218                     le32_to_cpu(missed_beacon->consecutive_missed_beacons),
 219                     le32_to_cpu(missed_beacon->total_missed_becons),
 220                     le32_to_cpu(missed_beacon->num_recvd_beacons),
 221                     le32_to_cpu(missed_beacon->num_expected_beacons));
 222                 if (!test_bit(STATUS_SCANNING, &priv->status))
 223                         iwl_init_sensitivity(priv);
 224         }
 225 }
 226 EXPORT_SYMBOL(iwl_rx_missed_beacon_notif);
 227
 228 void iwl_rx_spectrum_measure_notif(struct iwl_priv *priv,
 229                                           struct iwl_rx_mem_buffer *rxb)
 230 {
 231         struct iwl_rx_packet *pkt = rxb_addr(rxb);
 232         struct iwl_spectrum_notification *report = &(pkt->u.spectrum_notif);
 233
 234         if (!report->state) {
 235                 IWL_DEBUG_11H(priv,
 236                         "Spectrum Measure Notification: Start\n");
 237                 return;
 238         }
 239
 240         memcpy(&priv->measure_report, report, sizeof(*report));
 241         priv->measurement_status |= MEASUREMENT_READY;
 242 }
 243 EXPORT_SYMBOL(iwl_rx_spectrum_measure_notif);
 244
 245
 246
 247 /* Calculate noise level, based on measurements during network silence just
 248  *   before arriving beacon.  This measurement can be done only if we know
 249  *   exactly when to expect beacons, therefore only when we're associated. */
 250 static void iwl_rx_calc_noise(struct iwl_priv *priv)
 251 {
 252         struct statistics_rx_non_phy *rx_info
 253                                 = &(priv->statistics.rx.general);
 254         int num_active_rx = 0;
 255         int total_silence = 0;
 256         int bcn_silence_a =
 257                 le32_to_cpu(rx_info->beacon_silence_rssi_a) & IN_BAND_FILTER;
 258         int bcn_silence_b =
 259                 le32_to_cpu(rx_info->beacon_silence_rssi_b) & IN_BAND_FILTER;
 260         int bcn_silence_c =
 261                 le32_to_cpu(rx_info->beacon_silence_rssi_c) & IN_BAND_FILTER;
 262         int last_rx_noise;
 263
 264         if (bcn_silence_a) {
 265                 total_silence += bcn_silence_a;
 266                 num_active_rx++;
 267         }
 268         if (bcn_silence_b) {
 269                 total_silence += bcn_silence_b;
 270                 num_active_rx++;
 271         }
 272         if (bcn_silence_c) {
 273                 total_silence += bcn_silence_c;
 274                 num_active_rx++;
 275         }
 276
 277         /* Average among active antennas */
 278         if (num_active_rx)
 279                 last_rx_noise = (total_silence / num_active_rx) - 107;
 280         else
 281                 last_rx_noise = IWL_NOISE_MEAS_NOT_AVAILABLE;
 282
 283         IWL_DEBUG_CALIB(priv, "inband silence a %u, b %u, c %u, dBm %d\n",
 284                         bcn_silence_a, bcn_silence_b, bcn_silence_c,
 285                         last_rx_noise);
 286 }
 287
 288 #ifdef CONFIG_IWLWIFI_DEBUG
 289 /*
 290  *  based on the assumption of all statistics counter are in DWORD
 291  *  FIXME: This function is for debugging, do not deal with
 292  *  the case of counters roll-over.
 293  */
 294 static void iwl_accumulative_statistics(struct iwl_priv *priv,
 295                                         __le32 *stats)
 296 {
 297         int i;
 298         __le32 *prev_stats;
 299         u32 *accum_stats;
 300         u32 *delta, *max_delta;
 301
 302         prev_stats = (__le32 *)&priv->statistics;
 303         accum_stats = (u32 *)&priv->accum_statistics;
 304         delta = (u32 *)&priv->delta_statistics;
 305         max_delta = (u32 *)&priv->max_delta;
 306
 307         for (i = sizeof(__le32); i < sizeof(struct iwl_notif_statistics);
 308              i += sizeof(__le32), stats++, prev_stats++, delta++,
 309              max_delta++, accum_stats++) {
 310                 if (le32_to_cpu(*stats) > le32_to_cpu(*prev_stats)) {
 311                         *delta = (le32_to_cpu(*stats) -
 312                                 le32_to_cpu(*prev_stats));
 313                         *accum_stats += *delta;
 314                         if (*delta > *max_delta)
 315                                 *max_delta = *delta;
 316                 }
 317         }
 318
 319         /* reset accumulative statistics for "no-counter" type statistics */
 320         priv->accum_statistics.general.temperature =
 321                 priv->statistics.general.temperature;
 322         priv->accum_statistics.general.temperature_m =
 323                 priv->statistics.general.temperature_m;
 324         priv->accum_statistics.general.ttl_timestamp =
 325                 priv->statistics.general.ttl_timestamp;
 326         priv->accum_statistics.tx.tx_power.ant_a =
 327                 priv->statistics.tx.tx_power.ant_a;
 328         priv->accum_statistics.tx.tx_power.ant_b =
 329                 priv->statistics.tx.tx_power.ant_b;
 330         priv->accum_statistics.tx.tx_power.ant_c =
 331                 priv->statistics.tx.tx_power.ant_c;
 332 }
 333 #endif
 334
 335 #define REG_RECALIB_PERIOD (60)
 336
 337 /**
 338  * iwl_good_plcp_health - checks for plcp error.
 339  *
 340  * When the plcp error is exceeding the thresholds, reset the radio
 341  * to improve the throughput.
 342  */
 343 bool iwl_good_plcp_health(struct iwl_priv *priv,
 344                                 struct iwl_rx_packet *pkt)
 345 {
 346         bool rc = true;
 347         int combined_plcp_delta;
 348         unsigned int plcp_msec;
 349         unsigned long plcp_received_jiffies;
 350
 351         /*
 352          * check for plcp_err and trigger radio reset if it exceeds
 353          * the plcp error threshold plcp_delta.
 354          */
 355         plcp_received_jiffies = jiffies;
 356         plcp_msec = jiffies_to_msecs((long) plcp_received_jiffies -
 357                                         (long) priv->plcp_jiffies);
 358         priv->plcp_jiffies = plcp_received_jiffies;
 359         /*
 360          * check to make sure plcp_msec is not 0 to prevent division
 361          * by zero.
 362          */
 363         if (plcp_msec) {
 364                 combined_plcp_delta =
 365                         (le32_to_cpu(pkt->u.stats.rx.ofdm.plcp_err) -
 366                         le32_to_cpu(priv->statistics.rx.ofdm.plcp_err)) +
 367                         (le32_to_cpu(pkt->u.stats.rx.ofdm_ht.plcp_err) -
 368                         le32_to_cpu(priv->statistics.rx.ofdm_ht.plcp_err));
 369
 370                 if ((combined_plcp_delta > 0) &&
 371                     ((combined_plcp_delta * 100) / plcp_msec) >
 372                         priv->cfg->plcp_delta_threshold) {
 373                         /*
 374                          * if plcp_err exceed the threshold,
 375                          * the following data is printed in csv format:
 376                          *    Text: plcp_err exceeded %d,
 377                          *    Received ofdm.plcp_err,
 378                          *    Current ofdm.plcp_err,
 379                          *    Received ofdm_ht.plcp_err,
 380                          *    Current ofdm_ht.plcp_err,
 381                          *    combined_plcp_delta,
 382                          *    plcp_msec
 383                          */
 384                         IWL_DEBUG_RADIO(priv, "plcp_err exceeded %u, "
 385                                 "%u, %u, %u, %u, %d, %u mSecs\n",
 386                                 priv->cfg->plcp_delta_threshold,
 387                                 le32_to_cpu(pkt->u.stats.rx.ofdm.plcp_err),
 388                                 le32_to_cpu(priv->statistics.rx.ofdm.plcp_err),
 389                                 le32_to_cpu(pkt->u.stats.rx.ofdm_ht.plcp_err),
 390                                 le32_to_cpu(
 391                                   priv->statistics.rx.ofdm_ht.plcp_err),
 392                                 combined_plcp_delta, plcp_msec);
 393                         rc = false;
 394                 }
 395         }
 396         return rc;
 397 }
 398 EXPORT_SYMBOL(iwl_good_plcp_health);
 399
 400 static void iwl_recover_from_statistics(struct iwl_priv *priv,
 401                                 struct iwl_rx_packet *pkt)
 402 {
 403         if (test_bit(STATUS_EXIT_PENDING, &priv->status))
 404                 return;
 405         if (iwl_is_associated(priv)) {
 406                 if (priv->cfg->ops->lib->check_ack_health) {
 407                         if (!priv->cfg->ops->lib->check_ack_health(
 408                             priv, pkt)) {
 409                                 /*
 410                                  * low ack count detected
 411                                  * restart Firmware
 412                                  */
 413                                 IWL_ERR(priv, "low ack count detected, "
 414                                         "restart firmware\n");
 415                                 iwl_force_reset(priv, IWL_FW_RESET);
 416                         }
 417                 } else if (priv->cfg->ops->lib->check_plcp_health) {
 418                         if (!priv->cfg->ops->lib->check_plcp_health(
 419                             priv, pkt)) {
 420                                 /*
 421                                  * high plcp error detected
 422                                  * reset Radio
 423                                  */
 424                                 iwl_force_reset(priv, IWL_RF_RESET);
 425                         }
 426                 }
 427         }
 428 }
 429
 430 void iwl_rx_statistics(struct iwl_priv *priv,
 431                               struct iwl_rx_mem_buffer *rxb)
 432 {
 433         int change;
 434         struct iwl_rx_packet *pkt = rxb_addr(rxb);
 435
 436
 437         IWL_DEBUG_RX(priv, "Statistics notification received (%d vs %d).\n",
 438                      (int)sizeof(priv->statistics),
 439                      le32_to_cpu(pkt->len_n_flags) & FH_RSCSR_FRAME_SIZE_MSK);
 440
 441         change = ((priv->statistics.general.temperature !=
 442                    pkt->u.stats.general.temperature) ||
 443                   ((priv->statistics.flag &
 444                     STATISTICS_REPLY_FLG_HT40_MODE_MSK) !=
 445                    (pkt->u.stats.flag & STATISTICS_REPLY_FLG_HT40_MODE_MSK)));
 446
 447 #ifdef CONFIG_IWLWIFI_DEBUG
 448         iwl_accumulative_statistics(priv, (__le32 *)&pkt->u.stats);
 449 #endif
 450         iwl_recover_from_statistics(priv, pkt);
 451
 452         memcpy(&priv->statistics, &pkt->u.stats, sizeof(priv->statistics));
 453
 454         set_bit(STATUS_STATISTICS, &priv->status);
 455
 456         /* Reschedule the statistics timer to occur in
 457          * REG_RECALIB_PERIOD seconds to ensure we get a
 458          * thermal update even if the uCode doesn't give
 459          * us one */
 460         mod_timer(&priv->statistics_periodic, jiffies +
 461                   msecs_to_jiffies(REG_RECALIB_PERIOD * 1000));
 462
 463         if (unlikely(!test_bit(STATUS_SCANNING, &priv->status)) &&
 464             (pkt->hdr.cmd == STATISTICS_NOTIFICATION)) {
 465                 iwl_rx_calc_noise(priv);
 466                 queue_work(priv->workqueue, &priv->run_time_calib_work);
 467         }
 468         if (priv->cfg->ops->lib->temp_ops.temperature && change)
 469                 priv->cfg->ops->lib->temp_ops.temperature(priv);
 470 }
 471 EXPORT_SYMBOL(iwl_rx_statistics);
 472
 473 void iwl_reply_statistics(struct iwl_priv *priv,
 474                               struct iwl_rx_mem_buffer *rxb)
 475 {
 476         struct iwl_rx_packet *pkt = rxb_addr(rxb);
 477
 478         if (le32_to_cpu(pkt->u.stats.flag) & UCODE_STATISTICS_CLEAR_MSK) {
 479 #ifdef CONFIG_IWLWIFI_DEBUG
 480                 memset(&priv->accum_statistics, 0,
 481                         sizeof(struct iwl_notif_statistics));
 482                 memset(&priv->delta_statistics, 0,
 483                         sizeof(struct iwl_notif_statistics));
 484                 memset(&priv->max_delta, 0,
 485                         sizeof(struct iwl_notif_statistics));
 486 #endif
 487                 IWL_DEBUG_RX(priv, "Statistics have been cleared\n");
 488         }
 489         iwl_rx_statistics(priv, rxb);
 490 }
 491 EXPORT_SYMBOL(iwl_reply_statistics);
 492
 493 /*
 494  * returns non-zero if packet should be dropped
 495  */
 496 int iwl_set_decrypted_flag(struct iwl_priv *priv,
 497                            struct ieee80211_hdr *hdr,
 498                            u32 decrypt_res,
 499                            struct ieee80211_rx_status *stats)
 500 {
 501         u16 fc = le16_to_cpu(hdr->frame_control);
 502
 503         if (priv->active_rxon.filter_flags & RXON_FILTER_DIS_DECRYPT_MSK)
 504                 return 0;
 505
 506         if (!(fc & IEEE80211_FCTL_PROTECTED))
 507                 return 0;
 508
 509         IWL_DEBUG_RX(priv, "decrypt_res:0x%x\n", decrypt_res);
 510         switch (decrypt_res & RX_RES_STATUS_SEC_TYPE_MSK) {
 511         case RX_RES_STATUS_SEC_TYPE_TKIP:
 512                 /* The uCode has got a bad phase 1 Key, pushes the packet.
 513                  * Decryption will be done in SW. */
 514                 if ((decrypt_res & RX_RES_STATUS_DECRYPT_TYPE_MSK) ==
 515                     RX_RES_STATUS_BAD_KEY_TTAK)
 516                         break;
 517
 518         case RX_RES_STATUS_SEC_TYPE_WEP:
 519                 if ((decrypt_res & RX_RES_STATUS_DECRYPT_TYPE_MSK) ==
 520                     RX_RES_STATUS_BAD_ICV_MIC) {
 521                         /* bad ICV, the packet is destroyed since the
 522                          * decryption is inplace, drop it */
 523                         IWL_DEBUG_RX(priv, "Packet destroyed\n");
 524                         return -1;
 525                 }
 526         case RX_RES_STATUS_SEC_TYPE_CCMP:
 527                 if ((decrypt_res & RX_RES_STATUS_DECRYPT_TYPE_MSK) ==
 528                     RX_RES_STATUS_DECRYPT_OK) {
 529                         IWL_DEBUG_RX(priv, "hw decrypt successfully!!!\n");
 530                         stats->flag |= RX_FLAG_DECRYPTED;
 531                 }
 532                 break;
 533
 534         default:
 535                 break;
 536         }
 537         return 0;
 538 }
 539 EXPORT_SYMBOL(iwl_set_decrypted_flag);