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/slab.h>
  29 #include <linux/types.h>
  30 #include <linux/etherdevice.h>
  31 #include <net/mac80211.h>
  32
  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-helpers.h"
  39
  40 /* For active scan, listen ACTIVE_DWELL_TIME (msec) on each channel after
  41  * sending probe req.  This should be set long enough to hear probe responses
  42  * from more than one AP.  */
  43 #define IWL_ACTIVE_DWELL_TIME_24    (30)       /* all times in msec */
  44 #define IWL_ACTIVE_DWELL_TIME_52    (20)
  45
  46 #define IWL_ACTIVE_DWELL_FACTOR_24GHZ (3)
  47 #define IWL_ACTIVE_DWELL_FACTOR_52GHZ (2)
  48
  49 /* For passive scan, listen PASSIVE_DWELL_TIME (msec) on each channel.
  50  * Must be set longer than active dwell time.
  51  * For the most reliable scan, set > AP beacon interval (typically 100msec). */
  52 #define IWL_PASSIVE_DWELL_TIME_24   (20)       /* all times in msec */
  53 #define IWL_PASSIVE_DWELL_TIME_52   (10)
  54 #define IWL_PASSIVE_DWELL_BASE      (100)
  55 #define IWL_CHANNEL_TUNE_TIME       5
  56
  57
  58
  59 /**
  60  * iwl_scan_cancel - Cancel any currently executing HW scan
  61  *
  62  * NOTE: priv->mutex is not required before calling this function
  63  */
  64 int iwl_scan_cancel(struct iwl_priv *priv)
  65 {
  66         if (!test_bit(STATUS_SCAN_HW, &priv->status)) {
  67                 clear_bit(STATUS_SCANNING, &priv->status);
  68                 return 0;
  69         }
  70
  71         if (test_bit(STATUS_SCANNING, &priv->status)) {
  72                 if (!test_and_set_bit(STATUS_SCAN_ABORTING, &priv->status)) {
  73                         IWL_DEBUG_SCAN(priv, "Queuing scan abort.\n");
  74                         queue_work(priv->workqueue, &priv->abort_scan);
  75
  76                 } else
  77                         IWL_DEBUG_SCAN(priv, "Scan abort already in progress.\n");
  78
  79                 return test_bit(STATUS_SCANNING, &priv->status);
  80         }
  81
  82         return 0;
  83 }
  84 EXPORT_SYMBOL(iwl_scan_cancel);
  85 /**
  86  * iwl_scan_cancel_timeout - Cancel any currently executing HW scan
  87  * @ms: amount of time to wait (in milliseconds) for scan to abort
  88  *
  89  * NOTE: priv->mutex must be held before calling this function
  90  */
  91 int iwl_scan_cancel_timeout(struct iwl_priv *priv, unsigned long ms)
  92 {
  93         unsigned long now = jiffies;
  94         int ret;
  95
  96         ret = iwl_scan_cancel(priv);
  97         if (ret && ms) {
  98                 mutex_unlock(&priv->mutex);
  99                 while (!time_after(jiffies, now + msecs_to_jiffies(ms)) &&
 100                                 test_bit(STATUS_SCANNING, &priv->status))
 101                         msleep(1);
 102                 mutex_lock(&priv->mutex);
 103
 104                 return test_bit(STATUS_SCANNING, &priv->status);
 105         }
 106
 107         return ret;
 108 }
 109 EXPORT_SYMBOL(iwl_scan_cancel_timeout);
 110
 111 static int iwl_send_scan_abort(struct iwl_priv *priv)
 112 {
 113         int ret = 0;
 114         struct iwl_rx_packet *pkt;
 115         struct iwl_host_cmd cmd = {
 116                 .id = REPLY_SCAN_ABORT_CMD,
 117                 .flags = CMD_WANT_SKB,
 118         };
 119
 120         /* If there isn't a scan actively going on in the hardware
 121          * then we are in between scan bands and not actually
 122          * actively scanning, so don't send the abort command */
 123         if (!test_bit(STATUS_SCAN_HW, &priv->status)) {
 124                 clear_bit(STATUS_SCAN_ABORTING, &priv->status);
 125                 return 0;
 126         }
 127
 128         ret = iwl_send_cmd_sync(priv, &cmd);
 129         if (ret) {
 130                 clear_bit(STATUS_SCAN_ABORTING, &priv->status);
 131                 return ret;
 132         }
 133
 134         pkt = (struct iwl_rx_packet *)cmd.reply_page;
 135         if (pkt->u.status != CAN_ABORT_STATUS) {
 136                 /* The scan abort will return 1 for success or
 137                  * 2 for "failure".  A failure condition can be
 138                  * due to simply not being in an active scan which
 139                  * can occur if we send the scan abort before we
 140                  * the microcode has notified us that a scan is
 141                  * completed. */
 142                 IWL_DEBUG_INFO(priv, "SCAN_ABORT returned %d.\n", pkt->u.status);
 143                 clear_bit(STATUS_SCAN_ABORTING, &priv->status);
 144                 clear_bit(STATUS_SCAN_HW, &priv->status);
 145         }
 146
 147         iwl_free_pages(priv, cmd.reply_page);
 148
 149         return ret;
 150 }
 151
 152 /* Service response to REPLY_SCAN_CMD (0x80) */
 153 static void iwl_rx_reply_scan(struct iwl_priv *priv,
 154                               struct iwl_rx_mem_buffer *rxb)
 155 {
 156 #ifdef CONFIG_IWLWIFI_DEBUG
 157         struct iwl_rx_packet *pkt = rxb_addr(rxb);
 158         struct iwl_scanreq_notification *notif =
 159             (struct iwl_scanreq_notification *)pkt->u.raw;
 160
 161         IWL_DEBUG_RX(priv, "Scan request status = 0x%x\n", notif->status);
 162 #endif
 163 }
 164
 165 /* Service SCAN_START_NOTIFICATION (0x82) */
 166 static void iwl_rx_scan_start_notif(struct iwl_priv *priv,
 167                                     struct iwl_rx_mem_buffer *rxb)
 168 {
 169         struct iwl_rx_packet *pkt = rxb_addr(rxb);
 170         struct iwl_scanstart_notification *notif =
 171             (struct iwl_scanstart_notification *)pkt->u.raw;
 172         priv->scan_start_tsf = le32_to_cpu(notif->tsf_low);
 173         IWL_DEBUG_SCAN(priv, "Scan start: "
 174                        "%d [802.11%s] "
 175                        "(TSF: 0x%08X:%08X) - %d (beacon timer %u)\n",
 176                        notif->channel,
 177                        notif->band ? "bg" : "a",
 178                        le32_to_cpu(notif->tsf_high),
 179                        le32_to_cpu(notif->tsf_low),
 180                        notif->status, notif->beacon_timer);
 181 }
 182
 183 /* Service SCAN_RESULTS_NOTIFICATION (0x83) */
 184 static void iwl_rx_scan_results_notif(struct iwl_priv *priv,
 185                                       struct iwl_rx_mem_buffer *rxb)
 186 {
 187 #ifdef CONFIG_IWLWIFI_DEBUG
 188         struct iwl_rx_packet *pkt = rxb_addr(rxb);
 189         struct iwl_scanresults_notification *notif =
 190             (struct iwl_scanresults_notification *)pkt->u.raw;
 191
 192         IWL_DEBUG_SCAN(priv, "Scan ch.res: "
 193                        "%d [802.11%s] "
 194                        "(TSF: 0x%08X:%08X) - %d "
 195                        "elapsed=%lu usec\n",
 196                        notif->channel,
 197                        notif->band ? "bg" : "a",
 198                        le32_to_cpu(notif->tsf_high),
 199                        le32_to_cpu(notif->tsf_low),
 200                        le32_to_cpu(notif->statistics[0]),
 201                        le32_to_cpu(notif->tsf_low) - priv->scan_start_tsf);
 202 #endif
 203 }
 204
 205 /* Service SCAN_COMPLETE_NOTIFICATION (0x84) */
 206 static void iwl_rx_scan_complete_notif(struct iwl_priv *priv,
 207                                        struct iwl_rx_mem_buffer *rxb)
 208 {
 209 #ifdef CONFIG_IWLWIFI_DEBUG
 210         struct iwl_rx_packet *pkt = rxb_addr(rxb);
 211         struct iwl_scancomplete_notification *scan_notif = (void *)pkt->u.raw;
 212
 213         IWL_DEBUG_SCAN(priv, "Scan complete: %d channels (TSF 0x%08X:%08X) - %d\n",
 214                        scan_notif->scanned_channels,
 215                        scan_notif->tsf_low,
 216                        scan_notif->tsf_high, scan_notif->status);
 217 #endif
 218
 219         /* The HW is no longer scanning */
 220         clear_bit(STATUS_SCAN_HW, &priv->status);
 221
 222         IWL_DEBUG_INFO(priv, "Scan on %sGHz took %dms\n",
 223                        (priv->scan_band == IEEE80211_BAND_2GHZ) ? "2.4" : "5.2",
 224                        jiffies_to_msecs(elapsed_jiffies
 225                                         (priv->scan_start, jiffies)));
 226
 227         /*
 228          * If a request to abort was given, or the scan did not succeed
 229          * then we reset the scan state machine and terminate,
 230          * re-queuing another scan if one has been requested
 231          */
 232         if (test_and_clear_bit(STATUS_SCAN_ABORTING, &priv->status))
 233                 IWL_DEBUG_INFO(priv, "Aborted scan completed.\n");
 234
 235         IWL_DEBUG_INFO(priv, "Setting scan to off\n");
 236
 237         clear_bit(STATUS_SCANNING, &priv->status);
 238
 239         queue_work(priv->workqueue, &priv->scan_completed);
 240 }
 241
 242 void iwl_setup_rx_scan_handlers(struct iwl_priv *priv)
 243 {
 244         /* scan handlers */
 245         priv->rx_handlers[REPLY_SCAN_CMD] = iwl_rx_reply_scan;
 246         priv->rx_handlers[SCAN_START_NOTIFICATION] = iwl_rx_scan_start_notif;
 247         priv->rx_handlers[SCAN_RESULTS_NOTIFICATION] =
 248                                         iwl_rx_scan_results_notif;
 249         priv->rx_handlers[SCAN_COMPLETE_NOTIFICATION] =
 250                                         iwl_rx_scan_complete_notif;
 251 }
 252 EXPORT_SYMBOL(iwl_setup_rx_scan_handlers);
 253
 254 inline u16 iwl_get_active_dwell_time(struct iwl_priv *priv,
 255                                      enum ieee80211_band band,
 256                                      u8 n_probes)
 257 {
 258         if (band == IEEE80211_BAND_5GHZ)
 259                 return IWL_ACTIVE_DWELL_TIME_52 +
 260                         IWL_ACTIVE_DWELL_FACTOR_52GHZ * (n_probes + 1);
 261         else
 262                 return IWL_ACTIVE_DWELL_TIME_24 +
 263                         IWL_ACTIVE_DWELL_FACTOR_24GHZ * (n_probes + 1);
 264 }
 265 EXPORT_SYMBOL(iwl_get_active_dwell_time);
 266
 267 u16 iwl_get_passive_dwell_time(struct iwl_priv *priv,
 268                                enum ieee80211_band band,
 269                                struct ieee80211_vif *vif)
 270 {
 271         u16 passive = (band == IEEE80211_BAND_2GHZ) ?
 272             IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_24 :
 273             IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_52;
 274
 275         if (iwl_is_associated(priv)) {
 276                 /* If we're associated, we clamp the maximum passive
 277                  * dwell time to be 98% of the beacon interval (minus
 278                  * 2 * channel tune time) */
 279                 passive = vif ? vif->bss_conf.beacon_int : 0;
 280                 if ((passive > IWL_PASSIVE_DWELL_BASE) || !passive)
 281                         passive = IWL_PASSIVE_DWELL_BASE;
 282                 passive = (passive * 98) / 100 - IWL_CHANNEL_TUNE_TIME * 2;
 283         }
 284
 285         return passive;
 286 }
 287 EXPORT_SYMBOL(iwl_get_passive_dwell_time);
 288
 289 void iwl_init_scan_params(struct iwl_priv *priv)
 290 {
 291         u8 ant_idx = fls(priv->hw_params.valid_tx_ant) - 1;
 292         if (!priv->scan_tx_ant[IEEE80211_BAND_5GHZ])
 293                 priv->scan_tx_ant[IEEE80211_BAND_5GHZ] = ant_idx;
 294         if (!priv->scan_tx_ant[IEEE80211_BAND_2GHZ])
 295                 priv->scan_tx_ant[IEEE80211_BAND_2GHZ] = ant_idx;
 296 }
 297 EXPORT_SYMBOL(iwl_init_scan_params);
 298
 299 static int iwl_scan_initiate(struct iwl_priv *priv, struct ieee80211_vif *vif)
 300 {
 301         WARN_ON(!mutex_is_locked(&priv->mutex));
 302
 303         IWL_DEBUG_INFO(priv, "Starting scan...\n");
 304         set_bit(STATUS_SCANNING, &priv->status);
 305         priv->is_internal_short_scan = false;
 306         priv->scan_start = jiffies;
 307
 308         if (WARN_ON(!priv->cfg->ops->utils->request_scan))
 309                 return -EOPNOTSUPP;
 310
 311         priv->cfg->ops->utils->request_scan(priv, vif);
 312
 313         return 0;
 314 }
 315
 316 int iwl_mac_hw_scan(struct ieee80211_hw *hw,
 317                     struct ieee80211_vif *vif,
 318                     struct cfg80211_scan_request *req)
 319 {
 320         struct iwl_priv *priv = hw->priv;
 321         int ret;
 322
 323         IWL_DEBUG_MAC80211(priv, "enter\n");
 324
 325         if (req->n_channels == 0)
 326                 return -EINVAL;
 327
 328         mutex_lock(&priv->mutex);
 329
 330         if (!iwl_is_ready_rf(priv)) {
 331                 ret = -EIO;
 332                 IWL_DEBUG_MAC80211(priv, "leave - not ready or exit pending\n");
 333                 goto out_unlock;
 334         }
 335
 336         if (test_bit(STATUS_SCANNING, &priv->status)) {
 337                 IWL_DEBUG_SCAN(priv, "Scan already in progress.\n");
 338                 ret = -EAGAIN;
 339                 goto out_unlock;
 340         }
 341
 342         if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
 343                 IWL_DEBUG_SCAN(priv, "Scan request while abort pending\n");
 344                 ret = -EAGAIN;
 345                 goto out_unlock;
 346         }
 347
 348         /* mac80211 will only ask for one band at a time */
 349         priv->scan_band = req->channels[0]->band;
 350         priv->scan_request = req;
 351
 352         ret = iwl_scan_initiate(priv, vif);
 353
 354         IWL_DEBUG_MAC80211(priv, "leave\n");
 355
 356 out_unlock:
 357         mutex_unlock(&priv->mutex);
 358
 359         return ret;
 360 }
 361 EXPORT_SYMBOL(iwl_mac_hw_scan);
 362
 363 /*
 364  * internal short scan, this function should only been called while associated.
 365  * It will reset and tune the radio to prevent possible RF related problem
 366  */
 367 void iwl_internal_short_hw_scan(struct iwl_priv *priv)
 368 {
 369         queue_work(priv->workqueue, &priv->start_internal_scan);
 370 }
 371
 372 void iwl_bg_start_internal_scan(struct work_struct *work)
 373 {
 374         struct iwl_priv *priv =
 375                 container_of(work, struct iwl_priv, start_internal_scan);
 376
 377         mutex_lock(&priv->mutex);
 378
 379         if (priv->is_internal_short_scan == true) {
 380                 IWL_DEBUG_SCAN(priv, "Internal scan already in progress\n");
 381                 goto unlock;
 382         }
 383
 384         if (!iwl_is_ready_rf(priv)) {
 385                 IWL_DEBUG_SCAN(priv, "not ready or exit pending\n");
 386                 goto unlock;
 387         }
 388
 389         if (test_bit(STATUS_SCANNING, &priv->status)) {
 390                 IWL_DEBUG_SCAN(priv, "Scan already in progress.\n");
 391                 goto unlock;
 392         }
 393
 394         if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
 395                 IWL_DEBUG_SCAN(priv, "Scan request while abort pending\n");
 396                 goto unlock;
 397         }
 398
 399         priv->scan_band = priv->band;
 400
 401         IWL_DEBUG_SCAN(priv, "Start internal short scan...\n");
 402         set_bit(STATUS_SCANNING, &priv->status);
 403         priv->is_internal_short_scan = true;
 404
 405         if (WARN_ON(!priv->cfg->ops->utils->request_scan))
 406                 goto unlock;
 407
 408         priv->cfg->ops->utils->request_scan(priv, NULL);
 409  unlock:
 410         mutex_unlock(&priv->mutex);
 411 }
 412 EXPORT_SYMBOL(iwl_bg_start_internal_scan);
 413
 414 void iwl_bg_scan_check(struct work_struct *data)
 415 {
 416         struct iwl_priv *priv =
 417             container_of(data, struct iwl_priv, scan_check.work);
 418
 419         if (test_bit(STATUS_EXIT_PENDING, &priv->status))
 420                 return;
 421
 422         mutex_lock(&priv->mutex);
 423         if (test_bit(STATUS_SCANNING, &priv->status) ||
 424             test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
 425                 IWL_DEBUG_SCAN(priv, "Scan completion watchdog resetting "
 426                         "adapter (%dms)\n",
 427                         jiffies_to_msecs(IWL_SCAN_CHECK_WATCHDOG));
 428
 429                 if (!test_bit(STATUS_EXIT_PENDING, &priv->status))
 430                         iwl_send_scan_abort(priv);
 431         }
 432         mutex_unlock(&priv->mutex);
 433 }
 434 EXPORT_SYMBOL(iwl_bg_scan_check);
 435
 436 /**
 437  * iwl_fill_probe_req - fill in all required fields and IE for probe request
 438  */
 439
 440 u16 iwl_fill_probe_req(struct iwl_priv *priv, struct ieee80211_mgmt *frame,
 441                        const u8 *ies, int ie_len, int left)
 442 {
 443         int len = 0;
 444         u8 *pos = NULL;
 445
 446         /* Make sure there is enough space for the probe request,
 447          * two mandatory IEs and the data */
 448         left -= 24;
 449         if (left < 0)
 450                 return 0;
 451
 452         frame->frame_control = cpu_to_le16(IEEE80211_STYPE_PROBE_REQ);
 453         memcpy(frame->da, iwl_bcast_addr, ETH_ALEN);
 454         memcpy(frame->sa, priv->mac_addr, ETH_ALEN);
 455         memcpy(frame->bssid, iwl_bcast_addr, ETH_ALEN);
 456         frame->seq_ctrl = 0;
 457
 458         len += 24;
 459
 460         /* ...next IE... */
 461         pos = &frame->u.probe_req.variable[0];
 462
 463         /* fill in our indirect SSID IE */
 464         left -= 2;
 465         if (left < 0)
 466                 return 0;
 467         *pos++ = WLAN_EID_SSID;
 468         *pos++ = 0;
 469
 470         len += 2;
 471
 472         if (WARN_ON(left < ie_len))
 473                 return len;
 474
 475         if (ies && ie_len) {
 476                 memcpy(pos, ies, ie_len);
 477                 len += ie_len;
 478         }
 479
 480         return (u16)len;
 481 }
 482 EXPORT_SYMBOL(iwl_fill_probe_req);
 483
 484 void iwl_bg_abort_scan(struct work_struct *work)
 485 {
 486         struct iwl_priv *priv = container_of(work, struct iwl_priv, abort_scan);
 487
 488         if (!test_bit(STATUS_READY, &priv->status) ||
 489             !test_bit(STATUS_GEO_CONFIGURED, &priv->status))
 490                 return;
 491
 492         mutex_lock(&priv->mutex);
 493
 494         set_bit(STATUS_SCAN_ABORTING, &priv->status);
 495         iwl_send_scan_abort(priv);
 496
 497         mutex_unlock(&priv->mutex);
 498 }
 499 EXPORT_SYMBOL(iwl_bg_abort_scan);
 500
 501 void iwl_bg_scan_completed(struct work_struct *work)
 502 {
 503         struct iwl_priv *priv =
 504             container_of(work, struct iwl_priv, scan_completed);
 505         bool internal = false;
 506
 507         IWL_DEBUG_SCAN(priv, "SCAN complete scan\n");
 508
 509         cancel_delayed_work(&priv->scan_check);
 510
 511         mutex_lock(&priv->mutex);
 512         if (priv->is_internal_short_scan) {
 513                 priv->is_internal_short_scan = false;
 514                 IWL_DEBUG_SCAN(priv, "internal short scan completed\n");
 515                 internal = true;
 516         }
 517         mutex_unlock(&priv->mutex);
 518
 519         /*
 520          * Do not hold mutex here since this will cause mac80211 to call
 521          * into driver again into functions that will attempt to take
 522          * mutex.
 523          */
 524         if (!internal)
 525                 ieee80211_scan_completed(priv->hw, false);
 526
 527         if (test_bit(STATUS_EXIT_PENDING, &priv->status))
 528                 return;
 529
 530         /* Since setting the TXPOWER may have been deferred while
 531          * performing the scan, fire one off */
 532         mutex_lock(&priv->mutex);
 533         iwl_set_tx_power(priv, priv->tx_power_user_lmt, true);
 534         mutex_unlock(&priv->mutex);
 535 }
 536 EXPORT_SYMBOL(iwl_bg_scan_completed);
 537
 538 void iwl_setup_scan_deferred_work(struct iwl_priv *priv)
 539 {
 540         INIT_WORK(&priv->scan_completed, iwl_bg_scan_completed);
 541         INIT_WORK(&priv->abort_scan, iwl_bg_abort_scan);
 542         INIT_WORK(&priv->start_internal_scan, iwl_bg_start_internal_scan);
 543         INIT_DELAYED_WORK(&priv->scan_check, iwl_bg_scan_check);
 544 }
 545 EXPORT_SYMBOL(iwl_setup_scan_deferred_work);
 546