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

   1 /******************************************************************************
   2  *
   3  * GPL LICENSE SUMMARY
   4  *
   5  * Copyright(c) 2008 - 2011 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 static int iwl_legacy_send_scan_abort(struct iwl_priv *priv)
  58 {
  59         int ret;
  60         struct iwl_rx_packet *pkt;
  61         struct iwl_host_cmd cmd = {
  62                 .id = REPLY_SCAN_ABORT_CMD,
  63                 .flags = CMD_WANT_SKB,
  64         };
  65
  66         /* Exit instantly with error when device is not ready
  67          * to receive scan abort command or it does not perform
  68          * hardware scan currently */
  69         if (!test_bit(STATUS_READY, &priv->status) ||
  70             !test_bit(STATUS_GEO_CONFIGURED, &priv->status) ||
  71             !test_bit(STATUS_SCAN_HW, &priv->status) ||
  72             test_bit(STATUS_FW_ERROR, &priv->status) ||
  73             test_bit(STATUS_EXIT_PENDING, &priv->status))
  74                 return -EIO;
  75
  76         ret = iwl_legacy_send_cmd_sync(priv, &cmd);
  77         if (ret)
  78                 return ret;
  79
  80         pkt = (struct iwl_rx_packet *)cmd.reply_page;
  81         if (pkt->u.status != CAN_ABORT_STATUS) {
  82                 /* The scan abort will return 1 for success or
  83                  * 2 for "failure".  A failure condition can be
  84                  * due to simply not being in an active scan which
  85                  * can occur if we send the scan abort before we
  86                  * the microcode has notified us that a scan is
  87                  * completed. */
  88                 IWL_DEBUG_SCAN(priv, "SCAN_ABORT ret %d.\n", pkt->u.status);
  89                 ret = -EIO;
  90         }
  91
  92         iwl_legacy_free_pages(priv, cmd.reply_page);
  93         return ret;
  94 }
  95
  96 static void iwl_legacy_complete_scan(struct iwl_priv *priv, bool aborted)
  97 {
  98         /* check if scan was requested from mac80211 */
  99         if (priv->scan_request) {
 100                 IWL_DEBUG_SCAN(priv, "Complete scan in mac80211\n");
 101                 ieee80211_scan_completed(priv->hw, aborted);
 102         }
 103
 104         priv->scan_vif = NULL;
 105         priv->scan_request = NULL;
 106 }
 107
 108 void iwl_legacy_force_scan_end(struct iwl_priv *priv)
 109 {
 110         lockdep_assert_held(&priv->mutex);
 111
 112         if (!test_bit(STATUS_SCANNING, &priv->status)) {
 113                 IWL_DEBUG_SCAN(priv, "Forcing scan end while not scanning\n");
 114                 return;
 115         }
 116
 117         IWL_DEBUG_SCAN(priv, "Forcing scan end\n");
 118         clear_bit(STATUS_SCANNING, &priv->status);
 119         clear_bit(STATUS_SCAN_HW, &priv->status);
 120         clear_bit(STATUS_SCAN_ABORTING, &priv->status);
 121         iwl_legacy_complete_scan(priv, true);
 122 }
 123
 124 static void iwl_legacy_do_scan_abort(struct iwl_priv *priv)
 125 {
 126         int ret;
 127
 128         lockdep_assert_held(&priv->mutex);
 129
 130         if (!test_bit(STATUS_SCANNING, &priv->status)) {
 131                 IWL_DEBUG_SCAN(priv, "Not performing scan to abort\n");
 132                 return;
 133         }
 134
 135         if (test_and_set_bit(STATUS_SCAN_ABORTING, &priv->status)) {
 136                 IWL_DEBUG_SCAN(priv, "Scan abort in progress\n");
 137                 return;
 138         }
 139
 140         ret = iwl_legacy_send_scan_abort(priv);
 141         if (ret) {
 142                 IWL_DEBUG_SCAN(priv, "Send scan abort failed %d\n", ret);
 143                 iwl_legacy_force_scan_end(priv);
 144         } else
 145                 IWL_DEBUG_SCAN(priv, "Successfully send scan abort\n");
 146 }
 147
 148 /**
 149  * iwl_scan_cancel - Cancel any currently executing HW scan
 150  */
 151 int iwl_legacy_scan_cancel(struct iwl_priv *priv)
 152 {
 153         IWL_DEBUG_SCAN(priv, "Queuing abort scan\n");
 154         queue_work(priv->workqueue, &priv->abort_scan);
 155         return 0;
 156 }
 157 EXPORT_SYMBOL(iwl_legacy_scan_cancel);
 158
 159 /**
 160  * iwl_legacy_scan_cancel_timeout - Cancel any currently executing HW scan
 161  * @ms: amount of time to wait (in milliseconds) for scan to abort
 162  *
 163  */
 164 int iwl_legacy_scan_cancel_timeout(struct iwl_priv *priv, unsigned long ms)
 165 {
 166         unsigned long timeout = jiffies + msecs_to_jiffies(ms);
 167
 168         lockdep_assert_held(&priv->mutex);
 169
 170         IWL_DEBUG_SCAN(priv, "Scan cancel timeout\n");
 171
 172         iwl_legacy_do_scan_abort(priv);
 173
 174         while (time_before_eq(jiffies, timeout)) {
 175                 if (!test_bit(STATUS_SCAN_HW, &priv->status))
 176                         break;
 177                 msleep(20);
 178         }
 179
 180         return test_bit(STATUS_SCAN_HW, &priv->status);
 181 }
 182 EXPORT_SYMBOL(iwl_legacy_scan_cancel_timeout);
 183
 184 /* Service response to REPLY_SCAN_CMD (0x80) */
 185 static void iwl_legacy_rx_reply_scan(struct iwl_priv *priv,
 186                               struct iwl_rx_mem_buffer *rxb)
 187 {
 188 #ifdef CONFIG_IWLWIFI_LEGACY_DEBUG
 189         struct iwl_rx_packet *pkt = rxb_addr(rxb);
 190         struct iwl_scanreq_notification *notif =
 191             (struct iwl_scanreq_notification *)pkt->u.raw;
 192
 193         IWL_DEBUG_SCAN(priv, "Scan request status = 0x%x\n", notif->status);
 194 #endif
 195 }
 196
 197 /* Service SCAN_START_NOTIFICATION (0x82) */
 198 static void iwl_legacy_rx_scan_start_notif(struct iwl_priv *priv,
 199                                     struct iwl_rx_mem_buffer *rxb)
 200 {
 201         struct iwl_rx_packet *pkt = rxb_addr(rxb);
 202         struct iwl_scanstart_notification *notif =
 203             (struct iwl_scanstart_notification *)pkt->u.raw;
 204         priv->scan_start_tsf = le32_to_cpu(notif->tsf_low);
 205         IWL_DEBUG_SCAN(priv, "Scan start: "
 206                        "%d [802.11%s] "
 207                        "(TSF: 0x%08X:%08X) - %d (beacon timer %u)\n",
 208                        notif->channel,
 209                        notif->band ? "bg" : "a",
 210                        le32_to_cpu(notif->tsf_high),
 211                        le32_to_cpu(notif->tsf_low),
 212                        notif->status, notif->beacon_timer);
 213 }
 214
 215 /* Service SCAN_RESULTS_NOTIFICATION (0x83) */
 216 static void iwl_legacy_rx_scan_results_notif(struct iwl_priv *priv,
 217                                       struct iwl_rx_mem_buffer *rxb)
 218 {
 219 #ifdef CONFIG_IWLWIFI_LEGACY_DEBUG
 220         struct iwl_rx_packet *pkt = rxb_addr(rxb);
 221         struct iwl_scanresults_notification *notif =
 222             (struct iwl_scanresults_notification *)pkt->u.raw;
 223
 224         IWL_DEBUG_SCAN(priv, "Scan ch.res: "
 225                        "%d [802.11%s] "
 226                        "(TSF: 0x%08X:%08X) - %d "
 227                        "elapsed=%lu usec\n",
 228                        notif->channel,
 229                        notif->band ? "bg" : "a",
 230                        le32_to_cpu(notif->tsf_high),
 231                        le32_to_cpu(notif->tsf_low),
 232                        le32_to_cpu(notif->statistics[0]),
 233                        le32_to_cpu(notif->tsf_low) - priv->scan_start_tsf);
 234 #endif
 235 }
 236
 237 /* Service SCAN_COMPLETE_NOTIFICATION (0x84) */
 238 static void iwl_legacy_rx_scan_complete_notif(struct iwl_priv *priv,
 239                                        struct iwl_rx_mem_buffer *rxb)
 240 {
 241
 242 #ifdef CONFIG_IWLWIFI_LEGACY_DEBUG
 243         struct iwl_rx_packet *pkt = rxb_addr(rxb);
 244         struct iwl_scancomplete_notification *scan_notif = (void *)pkt->u.raw;
 245 #endif
 246
 247         IWL_DEBUG_SCAN(priv,
 248                         "Scan complete: %d channels (TSF 0x%08X:%08X) - %d\n",
 249                        scan_notif->scanned_channels,
 250                        scan_notif->tsf_low,
 251                        scan_notif->tsf_high, scan_notif->status);
 252
 253         /* The HW is no longer scanning */
 254         clear_bit(STATUS_SCAN_HW, &priv->status);
 255
 256         IWL_DEBUG_SCAN(priv, "Scan on %sGHz took %dms\n",
 257                        (priv->scan_band == IEEE80211_BAND_2GHZ) ? "2.4" : "5.2",
 258                        jiffies_to_msecs(jiffies - priv->scan_start));
 259
 260         queue_work(priv->workqueue, &priv->scan_completed);
 261 }
 262
 263 void iwl_legacy_setup_rx_scan_handlers(struct iwl_priv *priv)
 264 {
 265         /* scan handlers */
 266         priv->rx_handlers[REPLY_SCAN_CMD] = iwl_legacy_rx_reply_scan;
 267         priv->rx_handlers[SCAN_START_NOTIFICATION] =
 268                                         iwl_legacy_rx_scan_start_notif;
 269         priv->rx_handlers[SCAN_RESULTS_NOTIFICATION] =
 270                                         iwl_legacy_rx_scan_results_notif;
 271         priv->rx_handlers[SCAN_COMPLETE_NOTIFICATION] =
 272                                         iwl_legacy_rx_scan_complete_notif;
 273 }
 274 EXPORT_SYMBOL(iwl_legacy_setup_rx_scan_handlers);
 275
 276 inline u16 iwl_legacy_get_active_dwell_time(struct iwl_priv *priv,
 277                                      enum ieee80211_band band,
 278                                      u8 n_probes)
 279 {
 280         if (band == IEEE80211_BAND_5GHZ)
 281                 return IWL_ACTIVE_DWELL_TIME_52 +
 282                         IWL_ACTIVE_DWELL_FACTOR_52GHZ * (n_probes + 1);
 283         else
 284                 return IWL_ACTIVE_DWELL_TIME_24 +
 285                         IWL_ACTIVE_DWELL_FACTOR_24GHZ * (n_probes + 1);
 286 }
 287 EXPORT_SYMBOL(iwl_legacy_get_active_dwell_time);
 288
 289 u16 iwl_legacy_get_passive_dwell_time(struct iwl_priv *priv,
 290                                enum ieee80211_band band,
 291                                struct ieee80211_vif *vif)
 292 {
 293         struct iwl_rxon_context *ctx;
 294         u16 passive = (band == IEEE80211_BAND_2GHZ) ?
 295             IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_24 :
 296             IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_52;
 297
 298         if (iwl_legacy_is_any_associated(priv)) {
 299                 /*
 300                  * If we're associated, we clamp the maximum passive
 301                  * dwell time to be 98% of the smallest beacon interval
 302                  * (minus 2 * channel tune time)
 303                  */
 304                 for_each_context(priv, ctx) {
 305                         u16 value;
 306
 307                         if (!iwl_legacy_is_associated_ctx(ctx))
 308                                 continue;
 309                         value = ctx->vif ? ctx->vif->bss_conf.beacon_int : 0;
 310                         if ((value > IWL_PASSIVE_DWELL_BASE) || !value)
 311                                 value = IWL_PASSIVE_DWELL_BASE;
 312                         value = (value * 98) / 100 - IWL_CHANNEL_TUNE_TIME * 2;
 313                         passive = min(value, passive);
 314                 }
 315         }
 316
 317         return passive;
 318 }
 319 EXPORT_SYMBOL(iwl_legacy_get_passive_dwell_time);
 320
 321 void iwl_legacy_init_scan_params(struct iwl_priv *priv)
 322 {
 323         u8 ant_idx = fls(priv->hw_params.valid_tx_ant) - 1;
 324         if (!priv->scan_tx_ant[IEEE80211_BAND_5GHZ])
 325                 priv->scan_tx_ant[IEEE80211_BAND_5GHZ] = ant_idx;
 326         if (!priv->scan_tx_ant[IEEE80211_BAND_2GHZ])
 327                 priv->scan_tx_ant[IEEE80211_BAND_2GHZ] = ant_idx;
 328 }
 329 EXPORT_SYMBOL(iwl_legacy_init_scan_params);
 330
 331 static int iwl_legacy_scan_initiate(struct iwl_priv *priv,
 332                                     struct ieee80211_vif *vif)
 333 {
 334         int ret;
 335
 336         lockdep_assert_held(&priv->mutex);
 337
 338         if (WARN_ON(!priv->cfg->ops->utils->request_scan))
 339                 return -EOPNOTSUPP;
 340
 341         cancel_delayed_work(&priv->scan_check);
 342
 343         if (!iwl_legacy_is_ready_rf(priv)) {
 344                 IWL_WARN(priv, "Request scan called when driver not ready.\n");
 345                 return -EIO;
 346         }
 347
 348         if (test_bit(STATUS_SCAN_HW, &priv->status)) {
 349                 IWL_DEBUG_SCAN(priv,
 350                         "Multiple concurrent scan requests in parallel.\n");
 351                 return -EBUSY;
 352         }
 353
 354         if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
 355                 IWL_DEBUG_SCAN(priv, "Scan request while abort pending.\n");
 356                 return -EBUSY;
 357         }
 358
 359         IWL_DEBUG_SCAN(priv, "Starting scan...\n");
 360
 361         set_bit(STATUS_SCANNING, &priv->status);
 362         priv->scan_start = jiffies;
 363
 364         ret = priv->cfg->ops->utils->request_scan(priv, vif);
 365         if (ret) {
 366                 clear_bit(STATUS_SCANNING, &priv->status);
 367                 return ret;
 368         }
 369
 370         queue_delayed_work(priv->workqueue, &priv->scan_check,
 371                            IWL_SCAN_CHECK_WATCHDOG);
 372
 373         return 0;
 374 }
 375
 376 int iwl_legacy_mac_hw_scan(struct ieee80211_hw *hw,
 377                     struct ieee80211_vif *vif,
 378                     struct cfg80211_scan_request *req)
 379 {
 380         struct iwl_priv *priv = hw->priv;
 381         int ret;
 382
 383         IWL_DEBUG_MAC80211(priv, "enter\n");
 384
 385         if (req->n_channels == 0)
 386                 return -EINVAL;
 387
 388         mutex_lock(&priv->mutex);
 389
 390         if (test_bit(STATUS_SCANNING, &priv->status)) {
 391                 IWL_DEBUG_SCAN(priv, "Scan already in progress.\n");
 392                 ret = -EAGAIN;
 393                 goto out_unlock;
 394         }
 395
 396         /* mac80211 will only ask for one band at a time */
 397         priv->scan_request = req;
 398         priv->scan_vif = vif;
 399         priv->scan_band = req->channels[0]->band;
 400
 401         ret = iwl_legacy_scan_initiate(priv, vif);
 402
 403         IWL_DEBUG_MAC80211(priv, "leave\n");
 404
 405 out_unlock:
 406         mutex_unlock(&priv->mutex);
 407
 408         return ret;
 409 }
 410 EXPORT_SYMBOL(iwl_legacy_mac_hw_scan);
 411
 412 static void iwl_legacy_bg_scan_check(struct work_struct *data)
 413 {
 414         struct iwl_priv *priv =
 415             container_of(data, struct iwl_priv, scan_check.work);
 416
 417         IWL_DEBUG_SCAN(priv, "Scan check work\n");
 418
 419         /* Since we are here firmware does not finish scan and
 420          * most likely is in bad shape, so we don't bother to
 421          * send abort command, just force scan complete to mac80211 */
 422         mutex_lock(&priv->mutex);
 423         iwl_legacy_force_scan_end(priv);
 424         mutex_unlock(&priv->mutex);
 425 }
 426
 427 /**
 428  * iwl_legacy_fill_probe_req - fill in all required fields and IE for probe request
 429  */
 430
 431 u16
 432 iwl_legacy_fill_probe_req(struct iwl_priv *priv, struct ieee80211_mgmt *frame,
 433                        const u8 *ta, const u8 *ies, int ie_len, int left)
 434 {
 435         int len = 0;
 436         u8 *pos = NULL;
 437
 438         /* Make sure there is enough space for the probe request,
 439          * two mandatory IEs and the data */
 440         left -= 24;
 441         if (left < 0)
 442                 return 0;
 443
 444         frame->frame_control = cpu_to_le16(IEEE80211_STYPE_PROBE_REQ);
 445         memcpy(frame->da, iwlegacy_bcast_addr, ETH_ALEN);
 446         memcpy(frame->sa, ta, ETH_ALEN);
 447         memcpy(frame->bssid, iwlegacy_bcast_addr, ETH_ALEN);
 448         frame->seq_ctrl = 0;
 449
 450         len += 24;
 451
 452         /* ...next IE... */
 453         pos = &frame->u.probe_req.variable[0];
 454
 455         /* fill in our indirect SSID IE */
 456         left -= 2;
 457         if (left < 0)
 458                 return 0;
 459         *pos++ = WLAN_EID_SSID;
 460         *pos++ = 0;
 461
 462         len += 2;
 463
 464         if (WARN_ON(left < ie_len))
 465                 return len;
 466
 467         if (ies && ie_len) {
 468                 memcpy(pos, ies, ie_len);
 469                 len += ie_len;
 470         }
 471
 472         return (u16)len;
 473 }
 474 EXPORT_SYMBOL(iwl_legacy_fill_probe_req);
 475
 476 static void iwl_legacy_bg_abort_scan(struct work_struct *work)
 477 {
 478         struct iwl_priv *priv = container_of(work, struct iwl_priv, abort_scan);
 479
 480         IWL_DEBUG_SCAN(priv, "Abort scan work\n");
 481
 482         /* We keep scan_check work queued in case when firmware will not
 483          * report back scan completed notification */
 484         mutex_lock(&priv->mutex);
 485         iwl_legacy_scan_cancel_timeout(priv, 200);
 486         mutex_unlock(&priv->mutex);
 487 }
 488
 489 static void iwl_legacy_bg_scan_completed(struct work_struct *work)
 490 {
 491         struct iwl_priv *priv =
 492             container_of(work, struct iwl_priv, scan_completed);
 493         bool aborted;
 494
 495         IWL_DEBUG_SCAN(priv, "Completed scan.\n");
 496
 497         cancel_delayed_work(&priv->scan_check);
 498
 499         mutex_lock(&priv->mutex);
 500
 501         aborted = test_and_clear_bit(STATUS_SCAN_ABORTING, &priv->status);
 502         if (aborted)
 503                 IWL_DEBUG_SCAN(priv, "Aborted scan completed.\n");
 504
 505         if (!test_and_clear_bit(STATUS_SCANNING, &priv->status)) {
 506                 IWL_DEBUG_SCAN(priv, "Scan already completed.\n");
 507                 goto out_settings;
 508         }
 509
 510         iwl_legacy_complete_scan(priv, aborted);
 511
 512 out_settings:
 513         /* Can we still talk to firmware ? */
 514         if (!iwl_legacy_is_ready_rf(priv))
 515                 goto out;
 516
 517         /*
 518          * We do not commit power settings while scan is pending,
 519          * do it now if the settings changed.
 520          */
 521         iwl_legacy_power_set_mode(priv, &priv->power_data.sleep_cmd_next, false);
 522         iwl_legacy_set_tx_power(priv, priv->tx_power_next, false);
 523
 524         priv->cfg->ops->utils->post_scan(priv);
 525
 526 out:
 527         mutex_unlock(&priv->mutex);
 528 }
 529
 530 void iwl_legacy_setup_scan_deferred_work(struct iwl_priv *priv)
 531 {
 532         INIT_WORK(&priv->scan_completed, iwl_legacy_bg_scan_completed);
 533         INIT_WORK(&priv->abort_scan, iwl_legacy_bg_abort_scan);
 534         INIT_DELAYED_WORK(&priv->scan_check, iwl_legacy_bg_scan_check);
 535 }
 536 EXPORT_SYMBOL(iwl_legacy_setup_scan_deferred_work);
 537
 538 void iwl_legacy_cancel_scan_deferred_work(struct iwl_priv *priv)
 539 {
 540         cancel_work_sync(&priv->abort_scan);
 541         cancel_work_sync(&priv->scan_completed);
 542
 543         if (cancel_delayed_work_sync(&priv->scan_check)) {
 544                 mutex_lock(&priv->mutex);
 545                 iwl_legacy_force_scan_end(priv);
 546                 mutex_unlock(&priv->mutex);
 547         }
 548 }
 549 EXPORT_SYMBOL(iwl_legacy_cancel_scan_deferred_work);