drivers/net/wireless/iwlwifi/iwl-scan.c

   1 /******************************************************************************
   2  *
   3  * GPL LICENSE SUMMARY
   4  *
   5  * Copyright(c) 2008 - 2010 Intel Corporation. All rights reserved.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of version 2 of the GNU General Public License as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110,
  19  * USA
  20  *
  21  * The full GNU General Public License is included in this distribution
  22  * in the file called LICENSE.GPL.
  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 #include <linux/types.h>
  29 #include <linux/etherdevice.h>
  30 #include <net/mac80211.h>
  31
  32 #include "iwl-eeprom.h"
  33 #include "iwl-dev.h"
  34 #include "iwl-core.h"
  35 #include "iwl-sta.h"
  36 #include "iwl-io.h"
  37 #include "iwl-helpers.h"
  38
  39 /* For active scan, listen ACTIVE_DWELL_TIME (msec) on each channel after
  40  * sending probe req.  This should be set long enough to hear probe responses
  41  * from more than one AP.  */
  42 #define IWL_ACTIVE_DWELL_TIME_24    (30)       /* all times in msec */
  43 #define IWL_ACTIVE_DWELL_TIME_52    (20)
  44
  45 #define IWL_ACTIVE_DWELL_FACTOR_24GHZ (3)
  46 #define IWL_ACTIVE_DWELL_FACTOR_52GHZ (2)
  47
  48 /* For passive scan, listen PASSIVE_DWELL_TIME (msec) on each channel.
  49  * Must be set longer than active dwell time.
  50  * For the most reliable scan, set > AP beacon interval (typically 100msec). */
  51 #define IWL_PASSIVE_DWELL_TIME_24   (20)       /* all times in msec */
  52 #define IWL_PASSIVE_DWELL_TIME_52   (10)
  53 #define IWL_PASSIVE_DWELL_BASE      (100)
  54 #define IWL_CHANNEL_TUNE_TIME       5
  55
  56
  57
  58 /**
  59  * iwl_scan_cancel - Cancel any currently executing HW scan
  60  *
  61  * NOTE: priv->mutex is not required before calling this function
  62  */
  63 int iwl_scan_cancel(struct iwl_priv *priv)
  64 {
  65         if (!test_bit(STATUS_SCAN_HW, &priv->status)) {
  66                 clear_bit(STATUS_SCANNING, &priv->status);
  67                 return 0;
  68         }
  69
  70         if (test_bit(STATUS_SCANNING, &priv->status)) {
  71                 if (!test_and_set_bit(STATUS_SCAN_ABORTING, &priv->status)) {
  72                         IWL_DEBUG_SCAN(priv, "Queuing scan abort.\n");
  73                         queue_work(priv->workqueue, &priv->abort_scan);
  74
  75                 } else
  76                         IWL_DEBUG_SCAN(priv, "Scan abort already in progress.\n");
  77
  78                 return test_bit(STATUS_SCANNING, &priv->status);
  79         }
  80
  81         return 0;
  82 }
  83 EXPORT_SYMBOL(iwl_scan_cancel);
  84 /**
  85  * iwl_scan_cancel_timeout - Cancel any currently executing HW scan
  86  * @ms: amount of time to wait (in milliseconds) for scan to abort
  87  *
  88  * NOTE: priv->mutex must be held before calling this function
  89  */
  90 int iwl_scan_cancel_timeout(struct iwl_priv *priv, unsigned long ms)
  91 {
  92         unsigned long now = jiffies;
  93         int ret;
  94
  95         ret = iwl_scan_cancel(priv);
  96         if (ret && ms) {
  97                 mutex_unlock(&priv->mutex);
  98                 while (!time_after(jiffies, now + msecs_to_jiffies(ms)) &&
  99                                 test_bit(STATUS_SCANNING, &priv->status))
 100                         msleep(1);
 101                 mutex_lock(&priv->mutex);
 102
 103                 return test_bit(STATUS_SCANNING, &priv->status);
 104         }
 105
 106         return ret;
 107 }
 108 EXPORT_SYMBOL(iwl_scan_cancel_timeout);
 109
 110 static int iwl_send_scan_abort(struct iwl_priv *priv)
 111 {
 112         int ret = 0;
 113         struct iwl_rx_packet *pkt;
 114         struct iwl_host_cmd cmd = {
 115                 .id = REPLY_SCAN_ABORT_CMD,
 116                 .flags = CMD_WANT_SKB,
 117         };
 118
 119         /* If there isn't a scan actively going on in the hardware
 120          * then we are in between scan bands and not actually
 121          * actively scanning, so don't send the abort command */
 122         if (!test_bit(STATUS_SCAN_HW, &priv->status)) {
 123                 clear_bit(STATUS_SCAN_ABORTING, &priv->status);
 124                 return 0;
 125         }
 126
 127         ret = iwl_send_cmd_sync(priv, &cmd);
 128         if (ret) {
 129                 clear_bit(STATUS_SCAN_ABORTING, &priv->status);
 130                 return ret;
 131         }
 132
 133         pkt = (struct iwl_rx_packet *)cmd.reply_page;
 134         if (pkt->u.status != CAN_ABORT_STATUS) {
 135                 /* The scan abort will return 1 for success or
 136                  * 2 for "failure".  A failure condition can be
 137                  * due to simply not being in an active scan which
 138                  * can occur if we send the scan abort before we
 139                  * the microcode has notified us that a scan is
 140                  * completed. */
 141                 IWL_DEBUG_INFO(priv, "SCAN_ABORT returned %d.\n", pkt->u.status);
 142                 clear_bit(STATUS_SCAN_ABORTING, &priv->status);
 143                 clear_bit(STATUS_SCAN_HW, &priv->status);
 144         }
 145
 146         iwl_free_pages(priv, cmd.reply_page);
 147
 148         return ret;
 149 }
 150
 151 /* Service response to REPLY_SCAN_CMD (0x80) */
 152 static void iwl_rx_reply_scan(struct iwl_priv *priv,
 153                               struct iwl_rx_mem_buffer *rxb)
 154 {
 155 #ifdef CONFIG_IWLWIFI_DEBUG
 156         struct iwl_rx_packet *pkt = rxb_addr(rxb);
 157         struct iwl_scanreq_notification *notif =
 158             (struct iwl_scanreq_notification *)pkt->u.raw;
 159
 160         IWL_DEBUG_RX(priv, "Scan request status = 0x%x\n", notif->status);
 161 #endif
 162 }
 163
 164 /* Service SCAN_START_NOTIFICATION (0x82) */
 165 static void iwl_rx_scan_start_notif(struct iwl_priv *priv,
 166                                     struct iwl_rx_mem_buffer *rxb)
 167 {
 168         struct iwl_rx_packet *pkt = rxb_addr(rxb);
 169         struct iwl_scanstart_notification *notif =
 170             (struct iwl_scanstart_notification *)pkt->u.raw;
 171         priv->scan_start_tsf = le32_to_cpu(notif->tsf_low);
 172         IWL_DEBUG_SCAN(priv, "Scan start: "
 173                        "%d [802.11%s] "
 174                        "(TSF: 0x%08X:%08X) - %d (beacon timer %u)\n",
 175                        notif->channel,
 176                        notif->band ? "bg" : "a",
 177                        le32_to_cpu(notif->tsf_high),
 178                        le32_to_cpu(notif->tsf_low),
 179                        notif->status, notif->beacon_timer);
 180 }
 181
 182 /* Service SCAN_RESULTS_NOTIFICATION (0x83) */
 183 static void iwl_rx_scan_results_notif(struct iwl_priv *priv,
 184                                       struct iwl_rx_mem_buffer *rxb)
 185 {
 186 #ifdef CONFIG_IWLWIFI_DEBUG
 187         struct iwl_rx_packet *pkt = rxb_addr(rxb);
 188         struct iwl_scanresults_notification *notif =
 189             (struct iwl_scanresults_notification *)pkt->u.raw;
 190
 191         IWL_DEBUG_SCAN(priv, "Scan ch.res: "
 192                        "%d [802.11%s] "
 193                        "(TSF: 0x%08X:%08X) - %d "
 194                        "elapsed=%lu usec\n",
 195                        notif->channel,
 196                        notif->band ? "bg" : "a",
 197                        le32_to_cpu(notif->tsf_high),
 198                        le32_to_cpu(notif->tsf_low),
 199                        le32_to_cpu(notif->statistics[0]),
 200                        le32_to_cpu(notif->tsf_low) - priv->scan_start_tsf);
 201 #endif
 202 }
 203
 204 /* Service SCAN_COMPLETE_NOTIFICATION (0x84) */
 205 static void iwl_rx_scan_complete_notif(struct iwl_priv *priv,
 206                                        struct iwl_rx_mem_buffer *rxb)
 207 {
 208 #ifdef CONFIG_IWLWIFI_DEBUG
 209         struct iwl_rx_packet *pkt = rxb_addr(rxb);
 210         struct iwl_scancomplete_notification *scan_notif = (void *)pkt->u.raw;
 211
 212         IWL_DEBUG_SCAN(priv, "Scan complete: %d channels (TSF 0x%08X:%08X) - %d\n",
 213                        scan_notif->scanned_channels,
 214                        scan_notif->tsf_low,
 215                        scan_notif->tsf_high, scan_notif->status);
 216 #endif
 217
 218         /* The HW is no longer scanning */
 219         clear_bit(STATUS_SCAN_HW, &priv->status);
 220
 221         IWL_DEBUG_INFO(priv, "Scan on %sGHz took %dms\n",
 222                        (priv->scan_band == IEEE80211_BAND_2GHZ) ? "2.4" : "5.2",
 223                        jiffies_to_msecs(elapsed_jiffies
 224                                         (priv->scan_start, jiffies)));
 225
 226         /*
 227          * If a request to abort was given, or the scan did not succeed
 228          * then we reset the scan state machine and terminate,
 229          * re-queuing another scan if one has been requested
 230          */
 231         if (test_and_clear_bit(STATUS_SCAN_ABORTING, &priv->status))
 232                 IWL_DEBUG_INFO(priv, "Aborted scan completed.\n");
 233
 234         IWL_DEBUG_INFO(priv, "Setting scan to off\n");
 235
 236         clear_bit(STATUS_SCANNING, &priv->status);
 237
 238         queue_work(priv->workqueue, &priv->scan_completed);
 239 }
 240
 241 void iwl_setup_rx_scan_handlers(struct iwl_priv *priv)
 242 {
 243         /* scan handlers */
 244         priv->rx_handlers[REPLY_SCAN_CMD] = iwl_rx_reply_scan;
 245         priv->rx_handlers[SCAN_START_NOTIFICATION] = iwl_rx_scan_start_notif;
 246         priv->rx_handlers[SCAN_RESULTS_NOTIFICATION] =
 247                                         iwl_rx_scan_results_notif;
 248         priv->rx_handlers[SCAN_COMPLETE_NOTIFICATION] =
 249                                         iwl_rx_scan_complete_notif;
 250 }
 251 EXPORT_SYMBOL(iwl_setup_rx_scan_handlers);
 252
 253 inline u16 iwl_get_active_dwell_time(struct iwl_priv *priv,
 254                                      enum ieee80211_band band,
 255                                      u8 n_probes)
 256 {
 257         if (band == IEEE80211_BAND_5GHZ)
 258                 return IWL_ACTIVE_DWELL_TIME_52 +
 259                         IWL_ACTIVE_DWELL_FACTOR_52GHZ * (n_probes + 1);
 260         else
 261                 return IWL_ACTIVE_DWELL_TIME_24 +
 262                         IWL_ACTIVE_DWELL_FACTOR_24GHZ * (n_probes + 1);
 263 }
 264 EXPORT_SYMBOL(iwl_get_active_dwell_time);
 265
 266 u16 iwl_get_passive_dwell_time(struct iwl_priv *priv,
 267                                enum ieee80211_band band)
 268 {
 269         u16 passive = (band == IEEE80211_BAND_2GHZ) ?
 270             IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_24 :
 271             IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_52;
 272
 273         if (iwl_is_associated(priv)) {
 274                 /* If we're associated, we clamp the maximum passive
 275                  * dwell time to be 98% of the beacon interval (minus
 276                  * 2 * channel tune time) */
 277                 passive = priv->beacon_int;
 278                 if ((passive > IWL_PASSIVE_DWELL_BASE) || !passive)
 279                         passive = IWL_PASSIVE_DWELL_BASE;
 280                 passive = (passive * 98) / 100 - IWL_CHANNEL_TUNE_TIME * 2;
 281         }
 282
 283         return passive;
 284 }
 285 EXPORT_SYMBOL(iwl_get_passive_dwell_time);
 286
 287 void iwl_init_scan_params(struct iwl_priv *priv)
 288 {
 289         u8 ant_idx = fls(priv->hw_params.valid_tx_ant) - 1;
 290         if (!priv->scan_tx_ant[IEEE80211_BAND_5GHZ])
 291                 priv->scan_tx_ant[IEEE80211_BAND_5GHZ] = ant_idx;
 292         if (!priv->scan_tx_ant[IEEE80211_BAND_2GHZ])
 293                 priv->scan_tx_ant[IEEE80211_BAND_2GHZ] = ant_idx;
 294 }
 295 EXPORT_SYMBOL(iwl_init_scan_params);
 296
 297 static int iwl_scan_initiate(struct iwl_priv *priv)
 298 {
 299         WARN_ON(!mutex_is_locked(&priv->mutex));
 300
 301         IWL_DEBUG_INFO(priv, "Starting scan...\n");
 302         set_bit(STATUS_SCANNING, &priv->status);
 303         priv->is_internal_short_scan = false;
 304         priv->scan_start = jiffies;
 305
 306         if (WARN_ON(!priv->cfg->ops->utils->request_scan))
 307                 return -EOPNOTSUPP;
 308
 309         priv->cfg->ops->utils->request_scan(priv);
 310
 311         return 0;
 312 }
 313
 314 int iwl_mac_hw_scan(struct ieee80211_hw *hw,
 315                     struct ieee80211_vif *vif,
 316                     struct cfg80211_scan_request *req)
 317 {
 318         struct iwl_priv *priv = hw->priv;
 319         int ret;
 320
 321         IWL_DEBUG_MAC80211(priv, "enter\n");
 322
 323         if (req->n_channels == 0)
 324                 return -EINVAL;
 325
 326         mutex_lock(&priv->mutex);
 327
 328         if (!iwl_is_ready_rf(priv)) {
 329                 ret = -EIO;
 330                 IWL_DEBUG_MAC80211(priv, "leave - not ready or exit pending\n");
 331                 goto out_unlock;
 332         }
 333
 334         if (test_bit(STATUS_SCANNING, &priv->status)) {
 335                 IWL_DEBUG_SCAN(priv, "Scan already in progress.\n");
 336                 ret = -EAGAIN;
 337                 goto out_unlock;
 338         }
 339
 340         if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
 341                 IWL_DEBUG_SCAN(priv, "Scan request while abort pending\n");
 342                 ret = -EAGAIN;
 343                 goto out_unlock;
 344         }
 345
 346         /* mac80211 will only ask for one band at a time */
 347         priv->scan_band = req->channels[0]->band;
 348         priv->scan_request = req;
 349
 350         ret = iwl_scan_initiate(priv);
 351
 352         IWL_DEBUG_MAC80211(priv, "leave\n");
 353
 354 out_unlock:
 355         mutex_unlock(&priv->mutex);
 356
 357         return ret;
 358 }
 359 EXPORT_SYMBOL(iwl_mac_hw_scan);
 360
 361 /*
 362  * internal short scan, this function should only been called while associated.
 363  * It will reset and tune the radio to prevent possible RF related problem
 364  */
 365 void iwl_internal_short_hw_scan(struct iwl_priv *priv)
 366 {
 367         queue_work(priv->workqueue, &priv->start_internal_scan);
 368 }
 369
 370 void iwl_bg_start_internal_scan(struct work_struct *work)
 371 {
 372         struct iwl_priv *priv =
 373                 container_of(work, struct iwl_priv, start_internal_scan);
 374
 375         mutex_lock(&priv->mutex);
 376
 377         if (!iwl_is_ready_rf(priv)) {
 378                 IWL_DEBUG_SCAN(priv, "not ready or exit pending\n");
 379                 goto unlock;
 380         }
 381
 382         if (test_bit(STATUS_SCANNING, &priv->status)) {
 383                 IWL_DEBUG_SCAN(priv, "Scan already in progress.\n");
 384                 goto unlock;
 385         }
 386
 387         if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
 388                 IWL_DEBUG_SCAN(priv, "Scan request while abort pending\n");
 389                 goto unlock;
 390         }
 391
 392         priv->scan_band = priv->band;
 393
 394         IWL_DEBUG_SCAN(priv, "Start internal short scan...\n");
 395         set_bit(STATUS_SCANNING, &priv->status);
 396         priv->is_internal_short_scan = true;
 397
 398         if (WARN_ON(!priv->cfg->ops->utils->request_scan))
 399                 goto unlock;
 400
 401         priv->cfg->ops->utils->request_scan(priv);
 402  unlock:
 403         mutex_unlock(&priv->mutex);
 404 }
 405 EXPORT_SYMBOL(iwl_bg_start_internal_scan);
 406
 407 void iwl_bg_scan_check(struct work_struct *data)
 408 {
 409         struct iwl_priv *priv =
 410             container_of(data, struct iwl_priv, scan_check.work);
 411
 412         if (test_bit(STATUS_EXIT_PENDING, &priv->status))
 413                 return;
 414
 415         mutex_lock(&priv->mutex);
 416         if (test_bit(STATUS_SCANNING, &priv->status) ||
 417             test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
 418                 IWL_DEBUG_SCAN(priv, "Scan completion watchdog resetting "
 419                         "adapter (%dms)\n",
 420                         jiffies_to_msecs(IWL_SCAN_CHECK_WATCHDOG));
 421
 422                 if (!test_bit(STATUS_EXIT_PENDING, &priv->status))
 423                         iwl_send_scan_abort(priv);
 424         }
 425         mutex_unlock(&priv->mutex);
 426 }
 427 EXPORT_SYMBOL(iwl_bg_scan_check);
 428
 429 /**
 430  * iwl_fill_probe_req - fill in all required fields and IE for probe request
 431  */
 432
 433 u16 iwl_fill_probe_req(struct iwl_priv *priv, struct ieee80211_mgmt *frame,
 434                        const u8 *ies, int ie_len, int left)
 435 {
 436         int len = 0;
 437         u8 *pos = NULL;
 438
 439         /* Make sure there is enough space for the probe request,
 440          * two mandatory IEs and the data */
 441         left -= 24;
 442         if (left < 0)
 443                 return 0;
 444
 445         frame->frame_control = cpu_to_le16(IEEE80211_STYPE_PROBE_REQ);
 446         memcpy(frame->da, iwl_bcast_addr, ETH_ALEN);
 447         memcpy(frame->sa, priv->mac_addr, ETH_ALEN);
 448         memcpy(frame->bssid, iwl_bcast_addr, ETH_ALEN);
 449         frame->seq_ctrl = 0;
 450
 451         len += 24;
 452
 453         /* ...next IE... */
 454         pos = &frame->u.probe_req.variable[0];
 455
 456         /* fill in our indirect SSID IE */
 457         left -= 2;
 458         if (left < 0)
 459                 return 0;
 460         *pos++ = WLAN_EID_SSID;
 461         *pos++ = 0;
 462
 463         len += 2;
 464
 465         if (WARN_ON(left < ie_len))
 466                 return len;
 467
 468         if (ies && ie_len) {
 469                 memcpy(pos, ies, ie_len);
 470                 len += ie_len;
 471         }
 472
 473         return (u16)len;
 474 }
 475 EXPORT_SYMBOL(iwl_fill_probe_req);
 476
 477 void iwl_bg_abort_scan(struct work_struct *work)
 478 {
 479         struct iwl_priv *priv = container_of(work, struct iwl_priv, abort_scan);
 480
 481         if (!test_bit(STATUS_READY, &priv->status) ||
 482             !test_bit(STATUS_GEO_CONFIGURED, &priv->status))
 483                 return;
 484
 485         mutex_lock(&priv->mutex);
 486
 487         set_bit(STATUS_SCAN_ABORTING, &priv->status);
 488         iwl_send_scan_abort(priv);
 489
 490         mutex_unlock(&priv->mutex);
 491 }
 492 EXPORT_SYMBOL(iwl_bg_abort_scan);
 493
 494 void iwl_bg_scan_completed(struct work_struct *work)
 495 {
 496         struct iwl_priv *priv =
 497             container_of(work, struct iwl_priv, scan_completed);
 498
 499         IWL_DEBUG_SCAN(priv, "SCAN complete scan\n");
 500
 501         cancel_delayed_work(&priv->scan_check);
 502
 503         if (!priv->is_internal_short_scan)
 504                 ieee80211_scan_completed(priv->hw, false);
 505         else {
 506                 priv->is_internal_short_scan = false;
 507                 IWL_DEBUG_SCAN(priv, "internal short scan completed\n");
 508         }
 509
 510         if (test_bit(STATUS_EXIT_PENDING, &priv->status))
 511                 return;
 512
 513         /* Since setting the TXPOWER may have been deferred while
 514          * performing the scan, fire one off */
 515         mutex_lock(&priv->mutex);
 516         iwl_set_tx_power(priv, priv->tx_power_user_lmt, true);
 517         mutex_unlock(&priv->mutex);
 518 }
 519 EXPORT_SYMBOL(iwl_bg_scan_completed);
 520
 521 void iwl_setup_scan_deferred_work(struct iwl_priv *priv)
 522 {
 523         INIT_WORK(&priv->scan_completed, iwl_bg_scan_completed);
 524         INIT_WORK(&priv->abort_scan, iwl_bg_abort_scan);
 525         INIT_WORK(&priv->start_internal_scan, iwl_bg_start_internal_scan);
 526         INIT_DELAYED_WORK(&priv->scan_check, iwl_bg_scan_check);
 527 }
 528 EXPORT_SYMBOL(iwl_setup_scan_deferred_work);
 529