text: /******************************************************************************
   *
   * GPL LICENSE SUMMARY
   *
   * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of version 2 of the GNU General Public License as
   * published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110,
   * USA
   *
   * The full GNU General Public License is included in this distribution
   * in the file called LICENSE.GPL.
   *
   * Contact Information:
   *  Intel Linux Wireless <ilw@linux.intel.com>
   * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
   *****************************************************************************/
  #include <linux/slab.h>
  #include <linux/types.h>
  #include <linux/etherdevice.h>
  #include <net/mac80211.h>
  
  #include "iwl-eeprom.h"
  #include "iwl-dev.h"
  #include "iwl-core.h"
  #include "iwl-io.h"
  #include "iwl-agn.h"
  #include "iwl-trans.h"
  
  /* For active scan, listen ACTIVE_DWELL_TIME (msec) on each channel after
   * sending probe req.  This should be set long enough to hear probe responses
   * from more than one AP.  */
  #define IWL_ACTIVE_DWELL_TIME_24    (30)       /* all times in msec */
  #define IWL_ACTIVE_DWELL_TIME_52    (20)
  
  #define IWL_ACTIVE_DWELL_FACTOR_24GHZ (3)
  #define IWL_ACTIVE_DWELL_FACTOR_52GHZ (2)
  
  /* For passive scan, listen PASSIVE_DWELL_TIME (msec) on each channel.
   * Must be set longer than active dwell time.
   * For the most reliable scan, set > AP beacon interval (typically 100msec). */
  #define IWL_PASSIVE_DWELL_TIME_24   (20)       /* all times in msec */
  #define IWL_PASSIVE_DWELL_TIME_52   (10)
  #define IWL_PASSIVE_DWELL_BASE      (100)
  #define IWL_CHANNEL_TUNE_TIME       5
  
  static int iwl_send_scan_abort(struct iwl_priv *priv)
  {
  	int ret;
  	struct iwl_rx_packet *pkt;
  	struct iwl_host_cmd cmd = {
  		.id = REPLY_SCAN_ABORT_CMD,
  		.flags = CMD_SYNC | CMD_WANT_SKB,
  	};
  
  	/* Exit instantly with error when device is not ready
  	 * to receive scan abort command or it does not perform
  	 * hardware scan currently */
  	if (!test_bit(STATUS_READY, &priv->shrd->status) ||
  	    !test_bit(STATUS_GEO_CONFIGURED, &priv->shrd->status) ||
  	    !test_bit(STATUS_SCAN_HW, &priv->shrd->status) ||
  	    test_bit(STATUS_FW_ERROR, &priv->shrd->status) ||
  	    test_bit(STATUS_EXIT_PENDING, &priv->shrd->status))
  		return -EIO;
  
  	ret = iwl_trans_send_cmd(trans(priv), &cmd);
  	if (ret)
  		return ret;
  
  	pkt = (struct iwl_rx_packet *)cmd.reply_page;
  	if (pkt->u.status != CAN_ABORT_STATUS) {
  		/* The scan abort will return 1 for success or
  		 * 2 for "failure".  A failure condition can be
  		 * due to simply not being in an active scan which
  		 * can occur if we send the scan abort before we
  		 * the microcode has notified us that a scan is
  		 * completed. */
  		IWL_DEBUG_SCAN(priv, "SCAN_ABORT ret %d.\n", pkt->u.status);
  		ret = -EIO;
  	}
  
  	iwl_free_pages(priv->shrd, cmd.reply_page);
  	return ret;
  }
  
  static void iwl_complete_scan(struct iwl_priv *priv, bool aborted)
  {
  	/* check if scan was requested from mac80211 */
  	if (priv->scan_request) {
  		IWL_DEBUG_SCAN(priv, "Complete scan in mac80211\n");
  		ieee80211_scan_completed(priv->hw, aborted);
  	}
  
  	if (priv->scan_type == IWL_SCAN_ROC) {
  		ieee80211_remain_on_channel_expired(priv->hw);
  		priv->hw_roc_channel = NULL;
  		schedule_delayed_work(&priv->hw_roc_disable_work, 10 * HZ);
  	}
  
  	priv->scan_type = IWL_SCAN_NORMAL;
  	priv->scan_vif = NULL;
  	priv->scan_request = NULL;
  }
  
  static void iwl_process_scan_complete(struct iwl_priv *priv)
  {
  	bool aborted;
  
  	lockdep_assert_held(&priv->shrd->mutex);
  
  	if (!test_and_clear_bit(STATUS_SCAN_COMPLETE, &priv->shrd->status))
  		return;
  
  	IWL_DEBUG_SCAN(priv, "Completed scan.\n");
  
  	cancel_delayed_work(&priv->scan_check);
  
  	aborted = test_and_clear_bit(STATUS_SCAN_ABORTING, &priv->shrd->status);
  	if (aborted)
  		IWL_DEBUG_SCAN(priv, "Aborted scan completed.\n");
  
  	if (!test_and_clear_bit(STATUS_SCANNING, &priv->shrd->status)) {
  		IWL_DEBUG_SCAN(priv, "Scan already completed.\n");
  		goto out_settings;
  	}
  
  	if (priv->scan_type == IWL_SCAN_ROC) {
  		ieee80211_remain_on_channel_expired(priv->hw);
  		priv->hw_roc_channel = NULL;
  		schedule_delayed_work(&priv->hw_roc_disable_work, 10 * HZ);
  	}
  
  	if (priv->scan_type != IWL_SCAN_NORMAL && !aborted) {
  		int err;
  
  		/* Check if mac80211 requested scan during our internal scan */
  		if (priv->scan_request == NULL)
  			goto out_complete;
  
  		/* If so request a new scan */
  		err = iwl_scan_initiate(priv, priv->scan_vif, IWL_SCAN_NORMAL,
  					priv->scan_request->channels[0]->band);
  		if (err) {
  			IWL_DEBUG_SCAN(priv,
  				"failed to initiate pending scan: %d\n", err);
  			aborted = true;
  			goto out_complete;
  		}
  
  		return;
  	}
  
  out_complete:
  	iwl_complete_scan(priv, aborted);
  
  out_settings:
  	/* Can we still talk to firmware ? */
  	if (!iwl_is_ready_rf(priv->shrd))
  		return;
  
  	iwlagn_post_scan(priv);
  }
  
  void iwl_force_scan_end(struct iwl_priv *priv)
  {
  	lockdep_assert_held(&priv->shrd->mutex);
  
  	if (!test_bit(STATUS_SCANNING, &priv->shrd->status)) {
  		IWL_DEBUG_SCAN(priv, "Forcing scan end while not scanning\n");
  		return;
  	}
  
  	IWL_DEBUG_SCAN(priv, "Forcing scan end\n");
  	clear_bit(STATUS_SCANNING, &priv->shrd->status);
  	clear_bit(STATUS_SCAN_HW, &priv->shrd->status);
  	clear_bit(STATUS_SCAN_ABORTING, &priv->shrd->status);
  	clear_bit(STATUS_SCAN_COMPLETE, &priv->shrd->status);
  	iwl_complete_scan(priv, true);
  }
  
  static void iwl_do_scan_abort(struct iwl_priv *priv)
  {
  	int ret;
  
  	lockdep_assert_held(&priv->shrd->mutex);
  
  	if (!test_bit(STATUS_SCANNING, &priv->shrd->status)) {
  		IWL_DEBUG_SCAN(priv, "Not performing scan to abort\n");
  		return;
  	}
  
  	if (test_and_set_bit(STATUS_SCAN_ABORTING, &priv->shrd->status)) {
  		IWL_DEBUG_SCAN(priv, "Scan abort in progress\n");
  		return;
  	}
  
  	ret = iwl_send_scan_abort(priv);
  	if (ret) {
  		IWL_DEBUG_SCAN(priv, "Send scan abort failed %d\n", ret);
  		iwl_force_scan_end(priv);
  	} else
  		IWL_DEBUG_SCAN(priv, "Successfully send scan abort\n");
  }
  
  /**
   * iwl_scan_cancel - Cancel any currently executing HW scan
   */
  int iwl_scan_cancel(struct iwl_priv *priv)
  {
  	IWL_DEBUG_SCAN(priv, "Queuing abort scan\n");
  	queue_work(priv->shrd->workqueue, &priv->abort_scan);
  	return 0;
  }
  
  /**
   * iwl_scan_cancel_timeout - Cancel any currently executing HW scan
   * @ms: amount of time to wait (in milliseconds) for scan to abort
   *
   */
  void iwl_scan_cancel_timeout(struct iwl_priv *priv, unsigned long ms)
  {
  	unsigned long timeout = jiffies + msecs_to_jiffies(ms);
  
  	lockdep_assert_held(&priv->shrd->mutex);
  
  	IWL_DEBUG_SCAN(priv, "Scan cancel timeout\n");
  
  	iwl_do_scan_abort(priv);
  
  	while (time_before_eq(jiffies, timeout)) {
  		if (!test_bit(STATUS_SCAN_HW, &priv->shrd->status))
  			goto finished;
  		msleep(20);
  	}
  
  	return;
  
   finished:
  	/*
  	 * Now STATUS_SCAN_HW is clear. This means that the
  	 * device finished, but the background work is going
  	 * to execute at best as soon as we release the mutex.
  	 * Since we need to be able to issue a new scan right
  	 * after this function returns, run the complete here.
  	 * The STATUS_SCAN_COMPLETE bit will then be cleared
  	 * and prevent the background work from "completing"
  	 * a possible new scan.
  	 */
  	iwl_process_scan_complete(priv);
  }
  
  /* Service response to REPLY_SCAN_CMD (0x80) */
  static int iwl_rx_reply_scan(struct iwl_priv *priv,
  			      struct iwl_rx_mem_buffer *rxb,
  			      struct iwl_device_cmd *cmd)
  {
  #ifdef CONFIG_IWLWIFI_DEBUG
  	struct iwl_rx_packet *pkt = rxb_addr(rxb);
  	struct iwl_scanreq_notification *notif =
  	    (struct iwl_scanreq_notification *)pkt->u.raw;
  
  	IWL_DEBUG_SCAN(priv, "Scan request status = 0x%x\n", notif->status);
  #endif
  	return 0;
  }
  
  /* Service SCAN_START_NOTIFICATION (0x82) */
  static int iwl_rx_scan_start_notif(struct iwl_priv *priv,
  				    struct iwl_rx_mem_buffer *rxb,
  				    struct iwl_device_cmd *cmd)
  {
  	struct iwl_rx_packet *pkt = rxb_addr(rxb);
  	struct iwl_scanstart_notification *notif =
  	    (struct iwl_scanstart_notification *)pkt->u.raw;
  	priv->scan_start_tsf = le32_to_cpu(notif->tsf_low);
  	IWL_DEBUG_SCAN(priv, "Scan start: "
  		       "%d [802.11%s] "
  		       "(TSF: 0x%08X:%08X) - %d (beacon timer %u)\n",
  		       notif->channel,
  		       notif->band ? "bg" : "a",
  		       le32_to_cpu(notif->tsf_high),
  		       le32_to_cpu(notif->tsf_low),
  		       notif->status, notif->beacon_timer);
  
  	if (priv->scan_type == IWL_SCAN_ROC &&
  	    !priv->hw_roc_start_notified) {
  		ieee80211_ready_on_channel(priv->hw);
  		priv->hw_roc_start_notified = true;
  	}
  
  	return 0;
  }
  
  /* Service SCAN_RESULTS_NOTIFICATION (0x83) */
  static int iwl_rx_scan_results_notif(struct iwl_priv *priv,
  				      struct iwl_rx_mem_buffer *rxb,
  				      struct iwl_device_cmd *cmd)
  {
  #ifdef CONFIG_IWLWIFI_DEBUG
  	struct iwl_rx_packet *pkt = rxb_addr(rxb);
  	struct iwl_scanresults_notification *notif =
  	    (struct iwl_scanresults_notification *)pkt->u.raw;
  
  	IWL_DEBUG_SCAN(priv, "Scan ch.res: "
  		       "%d [802.11%s] "
  		       "probe status: %u:%u "
  		       "(TSF: 0x%08X:%08X) - %d "
  		       "elapsed=%lu usec\n",
  		       notif->channel,
  		       notif->band ? "bg" : "a",
  		       notif->probe_status, notif->num_probe_not_sent,
  		       le32_to_cpu(notif->tsf_high),
  		       le32_to_cpu(notif->tsf_low),
  		       le32_to_cpu(notif->statistics[0]),
  		       le32_to_cpu(notif->tsf_low) - priv->scan_start_tsf);
  #endif
  	return 0;
  }
  
  /* Service SCAN_COMPLETE_NOTIFICATION (0x84) */
  static int iwl_rx_scan_complete_notif(struct iwl_priv *priv,
  				       struct iwl_rx_mem_buffer *rxb,
  				       struct iwl_device_cmd *cmd)
  {
  	struct iwl_rx_packet *pkt = rxb_addr(rxb);
  	struct iwl_scancomplete_notification *scan_notif = (void *)pkt->u.raw;
  
  	IWL_DEBUG_SCAN(priv, "Scan complete: %d channels (TSF 0x%08X:%08X) - %d\n",
  		       scan_notif->scanned_channels,
  		       scan_notif->tsf_low,
  		       scan_notif->tsf_high, scan_notif->status);
  
  	IWL_DEBUG_SCAN(priv, "Scan on %sGHz took %dms\n",
  		       (priv->scan_band == IEEE80211_BAND_2GHZ) ? "2.4" : "5.2",
  		       jiffies_to_msecs(jiffies - priv->scan_start));
  
  	/*
  	 * When aborting, we run the scan completed background work inline
  	 * and the background work must then do nothing. The SCAN_COMPLETE
  	 * bit helps implement that logic and thus needs to be set before
  	 * queueing the work. Also, since the scan abort waits for SCAN_HW
  	 * to clear, we need to set SCAN_COMPLETE before clearing SCAN_HW
  	 * to avoid a race there.
  	 */
  	set_bit(STATUS_SCAN_COMPLETE, &priv->shrd->status);
  	clear_bit(STATUS_SCAN_HW, &priv->shrd->status);
  	queue_work(priv->shrd->workqueue, &priv->scan_completed);
  
  	if (priv->iw_mode != NL80211_IFTYPE_ADHOC &&
  	    iwl_advanced_bt_coexist(priv) &&
  	    priv->bt_status != scan_notif->bt_status) {
  		if (scan_notif->bt_status) {
  			/* BT on */
  			if (!priv->bt_ch_announce)
  				priv->bt_traffic_load =
  					IWL_BT_COEX_TRAFFIC_LOAD_HIGH;
  			/*
  			 * otherwise, no traffic load information provided
  			 * no changes made
  			 */
  		} else {
  			/* BT off */
  			priv->bt_traffic_load =
  				IWL_BT_COEX_TRAFFIC_LOAD_NONE;
  		}
  		priv->bt_status = scan_notif->bt_status;
  		queue_work(priv->shrd->workqueue,
  			   &priv->bt_traffic_change_work);
  	}
  	return 0;
  }
  
  void iwl_setup_rx_scan_handlers(struct iwl_priv *priv)
  {
  	/* scan handlers */
  	priv->rx_handlers[REPLY_SCAN_CMD] = iwl_rx_reply_scan;
  	priv->rx_handlers[SCAN_START_NOTIFICATION] = iwl_rx_scan_start_notif;
  	priv->rx_handlers[SCAN_RESULTS_NOTIFICATION] =
  					iwl_rx_scan_results_notif;
  	priv->rx_handlers[SCAN_COMPLETE_NOTIFICATION] =
  					iwl_rx_scan_complete_notif;
  }
  
  static u16 iwl_get_active_dwell_time(struct iwl_priv *priv,
  				     enum ieee80211_band band, u8 n_probes)
  {
  	if (band == IEEE80211_BAND_5GHZ)
  		return IWL_ACTIVE_DWELL_TIME_52 +
  			IWL_ACTIVE_DWELL_FACTOR_52GHZ * (n_probes + 1);
  	else
  		return IWL_ACTIVE_DWELL_TIME_24 +
  			IWL_ACTIVE_DWELL_FACTOR_24GHZ * (n_probes + 1);
  }
  
  static u16 iwl_limit_dwell(struct iwl_priv *priv, u16 dwell_time)
  {
  	struct iwl_rxon_context *ctx;
  
  	/*
  	 * If we're associated, we clamp the dwell time 98%
  	 * of the smallest beacon interval (minus 2 * channel
  	 * tune time)
  	 */
  	for_each_context(priv, ctx) {
  		u16 value;
  
  		if (!iwl_is_associated_ctx(ctx))
  			continue;
  		if (ctx->staging.dev_type == RXON_DEV_TYPE_P2P)
  			continue;
  		value = ctx->beacon_int;
  		if (!value)
  			value = IWL_PASSIVE_DWELL_BASE;
  		value = (value * 98) / 100 - IWL_CHANNEL_TUNE_TIME * 2;
  		dwell_time = min(value, dwell_time);
  	}
  
  	return dwell_time;
  }
  
  static u16 iwl_get_passive_dwell_time(struct iwl_priv *priv,
  				      enum ieee80211_band band)
  {
  	u16 passive = (band == IEEE80211_BAND_2GHZ) ?
  	    IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_24 :
  	    IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_52;
  
  	return iwl_limit_dwell(priv, passive);
  }
  
  static int iwl_get_single_channel_for_scan(struct iwl_priv *priv,
  					   struct ieee80211_vif *vif,
  					   enum ieee80211_band band,
  					   struct iwl_scan_channel *scan_ch)
  {
  	const struct ieee80211_supported_band *sband;
  	u16 passive_dwell = 0;
  	u16 active_dwell = 0;
  	int added = 0;
  	u16 channel = 0;
  
  	sband = iwl_get_hw_mode(priv, band);
  	if (!sband) {
  		IWL_ERR(priv, "invalid band\n");
  		return added;
  	}
  
  	active_dwell = iwl_get_active_dwell_time(priv, band, 0);
  	passive_dwell = iwl_get_passive_dwell_time(priv, band);
  
  	if (passive_dwell <= active_dwell)
  		passive_dwell = active_dwell + 1;
  
  	channel = iwl_get_single_channel_number(priv, band);
  	if (channel) {
  		scan_ch->channel = cpu_to_le16(channel);
  		scan_ch->type = SCAN_CHANNEL_TYPE_PASSIVE;
  		scan_ch->active_dwell = cpu_to_le16(active_dwell);
  		scan_ch->passive_dwell = cpu_to_le16(passive_dwell);
  		/* Set txpower levels to defaults */
  		scan_ch->dsp_atten = 110;
  		if (band == IEEE80211_BAND_5GHZ)
  			scan_ch->tx_gain = ((1 << 5) | (3 << 3)) | 3;
  		else
  			scan_ch->tx_gain = ((1 << 5) | (5 << 3));
  		added++;
  	} else
  		IWL_ERR(priv, "no valid channel found\n");
  	return added;
  }
  
  static int iwl_get_channels_for_scan(struct iwl_priv *priv,
  				     struct ieee80211_vif *vif,
  				     enum ieee80211_band band,
  				     u8 is_active, u8 n_probes,
  				     struct iwl_scan_channel *scan_ch)
  {
  	struct ieee80211_channel *chan;
  	const struct ieee80211_supported_band *sband;
  	const struct iwl_channel_info *ch_info;
  	u16 passive_dwell = 0;
  	u16 active_dwell = 0;
  	int added, i;
  	u16 channel;
  
  	sband = iwl_get_hw_mode(priv, band);
  	if (!sband)
  		return 0;
  
  	active_dwell = iwl_get_active_dwell_time(priv, band, n_probes);
  	passive_dwell = iwl_get_passive_dwell_time(priv, band);
  
  	if (passive_dwell <= active_dwell)
  		passive_dwell = active_dwell + 1;
  
  	for (i = 0, added = 0; i < priv->scan_request->n_channels; i++) {
  		chan = priv->scan_request->channels[i];
  
  		if (chan->band != band)
  			continue;
  
  		channel = chan->hw_value;
  		scan_ch->channel = cpu_to_le16(channel);
  
  		ch_info = iwl_get_channel_info(priv, band, channel);
  		if (!is_channel_valid(ch_info)) {
  			IWL_DEBUG_SCAN(priv,
  				       "Channel %d is INVALID for this band.\n",
  				       channel);
  			continue;
  		}
  
  		if (!is_active || is_channel_passive(ch_info) ||
  		    (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN))
  			scan_ch->type = SCAN_CHANNEL_TYPE_PASSIVE;
  		else
  			scan_ch->type = SCAN_CHANNEL_TYPE_ACTIVE;
  
  		if (n_probes)
  			scan_ch->type |= IWL_SCAN_PROBE_MASK(n_probes);
  
  		scan_ch->active_dwell = cpu_to_le16(active_dwell);
  		scan_ch->passive_dwell = cpu_to_le16(passive_dwell);
  
  		/* Set txpower levels to defaults */
  		scan_ch->dsp_atten = 110;
  
  		/* NOTE: if we were doing 6Mb OFDM for scans we'd use
  		 * power level:
  		 * scan_ch->tx_gain = ((1 << 5) | (2 << 3)) | 3;
  		 */
  		if (band == IEEE80211_BAND_5GHZ)
  			scan_ch->tx_gain = ((1 << 5) | (3 << 3)) | 3;
  		else
  			scan_ch->tx_gain = ((1 << 5) | (5 << 3));
  
  		IWL_DEBUG_SCAN(priv, "Scanning ch=%d prob=0x%X [%s %d]\n",
  			       channel, le32_to_cpu(scan_ch->type),
  			       (scan_ch->type & SCAN_CHANNEL_TYPE_ACTIVE) ?
  				"ACTIVE" : "PASSIVE",
  			       (scan_ch->type & SCAN_CHANNEL_TYPE_ACTIVE) ?
  			       active_dwell : passive_dwell);
  
  		scan_ch++;
  		added++;
  	}
  
  	IWL_DEBUG_SCAN(priv, "total channels to scan %d\n", added);
  	return added;
  }
  
  static int iwlagn_request_scan(struct iwl_priv *priv, struct ieee80211_vif *vif)
  {
  	struct iwl_host_cmd cmd = {
  		.id = REPLY_SCAN_CMD,
  		.len = { sizeof(struct iwl_scan_cmd), },
  		.flags = CMD_SYNC,
  	};
  	struct iwl_scan_cmd *scan;
  	struct iwl_rxon_context *ctx = &priv->contexts[IWL_RXON_CTX_BSS];
  	u32 rate_flags = 0;
  	u16 cmd_len;
  	u16 rx_chain = 0;
  	enum ieee80211_band band;
  	u8 n_probes = 0;
  	u8 rx_ant = hw_params(priv).valid_rx_ant;
  	u8 rate;
  	bool is_active = false;
  	int  chan_mod;
  	u8 active_chains;
  	u8 scan_tx_antennas = hw_params(priv).valid_tx_ant;
  	int ret;
  
  	lockdep_assert_held(&priv->shrd->mutex);
  
  	if (vif)
  		ctx = iwl_rxon_ctx_from_vif(vif);
  
  	if (!priv->scan_cmd) {
  		priv->scan_cmd = kmalloc(sizeof(struct iwl_scan_cmd) +
  					 IWL_MAX_SCAN_SIZE, GFP_KERNEL);
  		if (!priv->scan_cmd) {
  			IWL_DEBUG_SCAN(priv,
  				       "fail to allocate memory for scan\n");
  			return -ENOMEM;
  		}
  	}
  	scan = priv->scan_cmd;
  	memset(scan, 0, sizeof(struct iwl_scan_cmd) + IWL_MAX_SCAN_SIZE);
  
  	scan->quiet_plcp_th = IWL_PLCP_QUIET_THRESH;
  	scan->quiet_time = IWL_ACTIVE_QUIET_TIME;
  
  	if (priv->scan_type != IWL_SCAN_ROC &&
  	    iwl_is_any_associated(priv)) {
  		u16 interval = 0;
  		u32 extra;
  		u32 suspend_time = 100;
  		u32 scan_suspend_time = 100;
  
  		IWL_DEBUG_INFO(priv, "Scanning while associated...\n");
  		switch (priv->scan_type) {
  		case IWL_SCAN_ROC:
  			WARN_ON(1);
  			break;
  		case IWL_SCAN_RADIO_RESET:
  			interval = 0;
  			break;
  		case IWL_SCAN_NORMAL:
  			interval = vif->bss_conf.beacon_int;
  			break;
  		}
  
  		scan->suspend_time = 0;
  		scan->max_out_time = cpu_to_le32(200 * 1024);
  		if (!interval)
  			interval = suspend_time;
  
  		extra = (suspend_time / interval) << 22;
  		scan_suspend_time = (extra |
  		    ((suspend_time % interval) * 1024));
  		scan->suspend_time = cpu_to_le32(scan_suspend_time);
  		IWL_DEBUG_SCAN(priv, "suspend_time 0x%X beacon interval %d\n",
  			       scan_suspend_time, interval);
  	} else if (priv->scan_type == IWL_SCAN_ROC) {
  		scan->suspend_time = 0;
  		scan->max_out_time = 0;
  		scan->quiet_time = 0;
  		scan->quiet_plcp_th = 0;
  	}
  
  	switch (priv->scan_type) {
  	case IWL_SCAN_RADIO_RESET:
  		IWL_DEBUG_SCAN(priv, "Start internal passive scan.\n");
  		break;
  	case IWL_SCAN_NORMAL:
  		if (priv->scan_request->n_ssids) {
  			int i, p = 0;
  			IWL_DEBUG_SCAN(priv, "Kicking off active scan\n");
  			for (i = 0; i < priv->scan_request->n_ssids; i++) {
  				/* always does wildcard anyway */
  				if (!priv->scan_request->ssids[i].ssid_len)
  					continue;
  				scan->direct_scan[p].id = WLAN_EID_SSID;
  				scan->direct_scan[p].len =
  					priv->scan_request->ssids[i].ssid_len;
  				memcpy(scan->direct_scan[p].ssid,
  				       priv->scan_request->ssids[i].ssid,
  				       priv->scan_request->ssids[i].ssid_len);
  				n_probes++;
  				p++;
  			}
  			is_active = true;
  		} else
  			IWL_DEBUG_SCAN(priv, "Start passive scan.\n");
  		break;
  	case IWL_SCAN_ROC:
  		IWL_DEBUG_SCAN(priv, "Start ROC scan.\n");
  		break;
  	}
  
  	scan->tx_cmd.tx_flags = TX_CMD_FLG_SEQ_CTL_MSK;
  	scan->tx_cmd.sta_id = ctx->bcast_sta_id;
  	scan->tx_cmd.stop_time.life_time = TX_CMD_LIFE_TIME_INFINITE;
  
  	switch (priv->scan_band) {
  	case IEEE80211_BAND_2GHZ:
  		scan->flags = RXON_FLG_BAND_24G_MSK | RXON_FLG_AUTO_DETECT_MSK;
  		chan_mod = le32_to_cpu(
  			priv->contexts[IWL_RXON_CTX_BSS].active.flags &
  						RXON_FLG_CHANNEL_MODE_MSK)
  				       >> RXON_FLG_CHANNEL_MODE_POS;
  		if ((priv->scan_request && priv->scan_request->no_cck) ||
  		    chan_mod == CHANNEL_MODE_PURE_40) {
  			rate = IWL_RATE_6M_PLCP;
  		} else {
  			rate = IWL_RATE_1M_PLCP;
  			rate_flags = RATE_MCS_CCK_MSK;
  		}
  		/*
  		 * Internal scans are passive, so we can indiscriminately set
  		 * the BT ignore flag on 2.4 GHz since it applies to TX only.
  		 */
  		if (priv->cfg->bt_params &&
  		    priv->cfg->bt_params->advanced_bt_coexist)
  			scan->tx_cmd.tx_flags |= TX_CMD_FLG_IGNORE_BT;
  		break;
  	case IEEE80211_BAND_5GHZ:
  		rate = IWL_RATE_6M_PLCP;
  		break;
  	default:
  		IWL_WARN(priv, "Invalid scan band\n");
  		return -EIO;
  	}
  
  	/*
  	 * If active scanning is requested but a certain channel is
  	 * marked passive, we can do active scanning if we detect
  	 * transmissions.
  	 *
  	 * There is an issue with some firmware versions that triggers
  	 * a sysassert on a "good CRC threshold" of zero (== disabled),
  	 * on a radar channel even though this means that we should NOT
  	 * send probes.
  	 *
  	 * The "good CRC threshold" is the number of frames that we
  	 * need to receive during our dwell time on a channel before
  	 * sending out probes -- setting this to a huge value will
  	 * mean we never reach it, but at the same time work around
  	 * the aforementioned issue. Thus use IWL_GOOD_CRC_TH_NEVER
  	 * here instead of IWL_GOOD_CRC_TH_DISABLED.
  	 *
  	 * This was fixed in later versions along with some other
  	 * scan changes, and the threshold behaves as a flag in those
  	 * versions.
  	 */
  	if (priv->new_scan_threshold_behaviour)
  		scan->good_CRC_th = is_active ? IWL_GOOD_CRC_TH_DEFAULT :
  						IWL_GOOD_CRC_TH_DISABLED;
  	else
  		scan->good_CRC_th = is_active ? IWL_GOOD_CRC_TH_DEFAULT :
  						IWL_GOOD_CRC_TH_NEVER;
  
  	band = priv->scan_band;
  
  	if (priv->cfg->scan_rx_antennas[band])
  		rx_ant = priv->cfg->scan_rx_antennas[band];
  
  	if (band == IEEE80211_BAND_2GHZ &&
  	    priv->cfg->bt_params &&
  	    priv->cfg->bt_params->advanced_bt_coexist) {
  		/* transmit 2.4 GHz probes only on first antenna */
  		scan_tx_antennas = first_antenna(scan_tx_antennas);
  	}
  
  	priv->scan_tx_ant[band] = iwl_toggle_tx_ant(priv,
  						    priv->scan_tx_ant[band],
  						    scan_tx_antennas);
  	rate_flags |= iwl_ant_idx_to_flags(priv->scan_tx_ant[band]);
  	scan->tx_cmd.rate_n_flags = iwl_hw_set_rate_n_flags(rate, rate_flags);
  
  	/* In power save mode use one chain, otherwise use all chains */
  	if (test_bit(STATUS_POWER_PMI, &priv->shrd->status)) {
  		/* rx_ant has been set to all valid chains previously */
  		active_chains = rx_ant &
  				((u8)(priv->chain_noise_data.active_chains));
  		if (!active_chains)
  			active_chains = rx_ant;
  
  		IWL_DEBUG_SCAN(priv, "chain_noise_data.active_chains: %u\n",
  				priv->chain_noise_data.active_chains);
  
  		rx_ant = first_antenna(active_chains);
  	}
  	if (priv->cfg->bt_params &&
  	    priv->cfg->bt_params->advanced_bt_coexist &&
  	    priv->bt_full_concurrent) {
  		/* operated as 1x1 in full concurrency mode */
  		rx_ant = first_antenna(rx_ant);
  	}
  
  	/* MIMO is not used here, but value is required */
  	rx_chain |=
  		hw_params(priv).valid_rx_ant << RXON_RX_CHAIN_VALID_POS;
  	rx_chain |= rx_ant << RXON_RX_CHAIN_FORCE_MIMO_SEL_POS;
  	rx_chain |= rx_ant << RXON_RX_CHAIN_FORCE_SEL_POS;
  	rx_chain |= 0x1 << RXON_RX_CHAIN_DRIVER_FORCE_POS;
  	scan->rx_chain = cpu_to_le16(rx_chain);
  	switch (priv->scan_type) {
  	case IWL_SCAN_NORMAL:
  		cmd_len = iwl_fill_probe_req(priv,
  					(struct ieee80211_mgmt *)scan->data,
  					vif->addr,
  					priv->scan_request->ie,
  					priv->scan_request->ie_len,
  					IWL_MAX_SCAN_SIZE - sizeof(*scan));
  		break;
  	case IWL_SCAN_RADIO_RESET:
  	case IWL_SCAN_ROC:
  		/* use bcast addr, will not be transmitted but must be valid */
  		cmd_len = iwl_fill_probe_req(priv,
  					(struct ieee80211_mgmt *)scan->data,
  					iwl_bcast_addr, NULL, 0,
  					IWL_MAX_SCAN_SIZE - sizeof(*scan));
  		break;
  	default:
  		BUG();
  	}
  	scan->tx_cmd.len = cpu_to_le16(cmd_len);
  
  	scan->filter_flags |= (RXON_FILTER_ACCEPT_GRP_MSK |
  			       RXON_FILTER_BCON_AWARE_MSK);
  
  	switch (priv->scan_type) {
  	case IWL_SCAN_RADIO_RESET:
  		scan->channel_count =
  			iwl_get_single_channel_for_scan(priv, vif, band,
  				(void *)&scan->data[cmd_len]);
  		break;
  	case IWL_SCAN_NORMAL:
  		scan->channel_count =
  			iwl_get_channels_for_scan(priv, vif, band,
  				is_active, n_probes,
  				(void *)&scan->data[cmd_len]);
  		break;
  	case IWL_SCAN_ROC: {
  		struct iwl_scan_channel *scan_ch;
  		int n_chan, i;
  		u16 dwell;
  
  		dwell = iwl_limit_dwell(priv, priv->hw_roc_duration);
  		n_chan = DIV_ROUND_UP(priv->hw_roc_duration, dwell);
  
  		scan->channel_count = n_chan;
  
  		scan_ch = (void *)&scan->data[cmd_len];
  
  		for (i = 0; i < n_chan; i++) {
  			scan_ch->type = SCAN_CHANNEL_TYPE_PASSIVE;
  			scan_ch->channel =
  				cpu_to_le16(priv->hw_roc_channel->hw_value);
  
  			if (i == n_chan - 1)
  				dwell = priv->hw_roc_duration - i * dwell;
  
  			scan_ch->active_dwell =
  			scan_ch->passive_dwell = cpu_to_le16(dwell);
  
  			/* Set txpower levels to defaults */
  			scan_ch->dsp_atten = 110;
  
  			/* NOTE: if we were doing 6Mb OFDM for scans we'd use
  			 * power level:
  			 * scan_ch->tx_gain = ((1 << 5) | (2 << 3)) | 3;
  			 */
  			if (priv->hw_roc_channel->band == IEEE80211_BAND_5GHZ)
  				scan_ch->tx_gain = ((1 << 5) | (3 << 3)) | 3;
  			else
  				scan_ch->tx_gain = ((1 << 5) | (5 << 3));
  
  			scan_ch++;
  		}
  		}
  
  		break;
  	}
  
  	if (scan->channel_count == 0) {
  		IWL_DEBUG_SCAN(priv, "channel count %d\n", scan->channel_count);
  		return -EIO;
  	}
  
  	cmd.len[0] += le16_to_cpu(scan->tx_cmd.len) +
  	    scan->channel_count * sizeof(struct iwl_scan_channel);
  	cmd.data[0] = scan;
  	cmd.dataflags[0] = IWL_HCMD_DFL_NOCOPY;
  	scan->len = cpu_to_le16(cmd.len[0]);
  
  	/* set scan bit here for PAN params */
  	set_bit(STATUS_SCAN_HW, &priv->shrd->status);
  
  	ret = iwlagn_set_pan_params(priv);
  	if (ret)
  		return ret;
  
  	ret = iwl_trans_send_cmd(trans(priv), &cmd);
  	if (ret) {
  		clear_bit(STATUS_SCAN_HW, &priv->shrd->status);
  		iwlagn_set_pan_params(priv);
  	}
  
  	return ret;
  }
  
  void iwl_init_scan_params(struct iwl_priv *priv)
  {
  	u8 ant_idx = fls(hw_params(priv).valid_tx_ant) - 1;
  	if (!priv->scan_tx_ant[IEEE80211_BAND_5GHZ])
  		priv->scan_tx_ant[IEEE80211_BAND_5GHZ] = ant_idx;
  	if (!priv->scan_tx_ant[IEEE80211_BAND_2GHZ])
  		priv->scan_tx_ant[IEEE80211_BAND_2GHZ] = ant_idx;
  }
  
  int __must_check iwl_scan_initiate(struct iwl_priv *priv,
  				   struct ieee80211_vif *vif,
  				   enum iwl_scan_type scan_type,
  				   enum ieee80211_band band)
  {
  	int ret;
  
  	lockdep_assert_held(&priv->shrd->mutex);
  
  	cancel_delayed_work(&priv->scan_check);
  
  	if (!iwl_is_ready_rf(priv->shrd)) {
  		IWL_WARN(priv, "Request scan called when driver not ready.\n");
  		return -EIO;
  	}
  
  	if (test_bit(STATUS_SCAN_HW, &priv->shrd->status)) {
  		IWL_DEBUG_SCAN(priv,
  			"Multiple concurrent scan requests in parallel.\n");
  		return -EBUSY;
  	}
  
  	if (test_bit(STATUS_SCAN_ABORTING, &priv->shrd->status)) {
  		IWL_DEBUG_SCAN(priv, "Scan request while abort pending.\n");
  		return -EBUSY;
  	}
  
  	IWL_DEBUG_SCAN(priv, "Starting %sscan...\n",
  			scan_type == IWL_SCAN_NORMAL ? "" :
  			scan_type == IWL_SCAN_ROC ? "remain-on-channel " :
  			"internal short ");
  
  	set_bit(STATUS_SCANNING, &priv->shrd->status);
  	priv->scan_type = scan_type;
  	priv->scan_start = jiffies;
  	priv->scan_band = band;
  
  	ret = iwlagn_request_scan(priv, vif);
  	if (ret) {
  		clear_bit(STATUS_SCANNING, &priv->shrd->status);
  		priv->scan_type = IWL_SCAN_NORMAL;
  		return ret;
  	}
  
  	queue_delayed_work(priv->shrd->workqueue, &priv->scan_check,
  			   IWL_SCAN_CHECK_WATCHDOG);
  
  	return 0;
  }
  
  
  /*
   * internal short scan, this function should only been called while associated.
   * It will reset and tune the radio to prevent possible RF related problem
   */
  void iwl_internal_short_hw_scan(struct iwl_priv *priv)
  {
  	queue_work(priv->shrd->workqueue, &priv->start_internal_scan);
  }
  
  static void iwl_bg_start_internal_scan(struct work_struct *work)
  {
  	struct iwl_priv *priv =
  		container_of(work, struct iwl_priv, start_internal_scan);
  
  	IWL_DEBUG_SCAN(priv, "Start internal scan\n");
  
  	mutex_lock(&priv->shrd->mutex);
  
  	if (priv->scan_type == IWL_SCAN_RADIO_RESET) {
  		IWL_DEBUG_SCAN(priv, "Internal scan already in progress\n");
  		goto unlock;
  	}
  
  	if (test_bit(STATUS_SCANNING, &priv->shrd->status)) {
  		IWL_DEBUG_SCAN(priv, "Scan already in progress.\n");
  		goto unlock;
  	}
  
  	if (iwl_scan_initiate(priv, NULL, IWL_SCAN_RADIO_RESET, priv->band))
  		IWL_DEBUG_SCAN(priv, "failed to start internal short scan\n");
   unlock:
  	mutex_unlock(&priv->shrd->mutex);
  }
  
  static void iwl_bg_scan_check(struct work_struct *data)
  {
  	struct iwl_priv *priv =
  	    container_of(data, struct iwl_priv, scan_check.work);
  
  	IWL_DEBUG_SCAN(priv, "Scan check work\n");
  
  	/* Since we are here firmware does not finish scan and
  	 * most likely is in bad shape, so we don't bother to
  	 * send abort command, just force scan complete to mac80211 */
  	mutex_lock(&priv->shrd->mutex);
  	iwl_force_scan_end(priv);
  	mutex_unlock(&priv->shrd->mutex);
  }
  
  /**
   * iwl_fill_probe_req - fill in all required fields and IE for probe request
   */
  
  u16 iwl_fill_probe_req(struct iwl_priv *priv, struct ieee80211_mgmt *frame,
  		       const u8 *ta, const u8 *ies, int ie_len, int left)
  {
  	int len = 0;
  	u8 *pos = NULL;
  
  	/* Make sure there is enough space for the probe request,
  	 * two mandatory IEs and the data */
  	left -= 24;
  	if (left < 0)
  		return 0;
  
  	frame->frame_control = cpu_to_le16(IEEE80211_STYPE_PROBE_REQ);
  	memcpy(frame->da, iwl_bcast_addr, ETH_ALEN);
  	memcpy(frame->sa, ta, ETH_ALEN);
  	memcpy(frame->bssid, iwl_bcast_addr, ETH_ALEN);
  	frame->seq_ctrl = 0;
  
  	len += 24;
  
  	/* ...next IE... */
  	pos = &frame->u.probe_req.variable[0];
  
  	/* fill in our indirect SSID IE */
  	left -= 2;
  	if (left < 0)
  		return 0;
  	*pos++ = WLAN_EID_SSID;
  	*pos++ = 0;
  
  	len += 2;
  
  	if (WARN_ON(left < ie_len))
  		return len;
  
  	if (ies && ie_len) {
  		memcpy(pos, ies, ie_len);
  		len += ie_len;
  	}
  
  	return (u16)len;
  }
  
  static void iwl_bg_abort_scan(struct work_struct *work)
  {
  	struct iwl_priv *priv = container_of(work, struct iwl_priv, abort_scan);
  
  	IWL_DEBUG_SCAN(priv, "Abort scan work\n");
  
  	/* We keep scan_check work queued in case when firmware will not
  	 * report back scan completed notification */
  	mutex_lock(&priv->shrd->mutex);
  	iwl_scan_cancel_timeout(priv, 200);
  	mutex_unlock(&priv->shrd->mutex);
  }
  
  static void iwl_bg_scan_completed(struct work_struct *work)
  {
  	struct iwl_priv *priv =
  		container_of(work, struct iwl_priv, scan_completed);
  
  	mutex_lock(&priv->shrd->mutex);
  	iwl_process_scan_complete(priv);
  	mutex_unlock(&priv->shrd->mutex);
  }
  
  void iwl_setup_scan_deferred_work(struct iwl_priv *priv)
  {
  	INIT_WORK(&priv->scan_completed, iwl_bg_scan_completed);
  	INIT_WORK(&priv->abort_scan, iwl_bg_abort_scan);
  	INIT_WORK(&priv->start_internal_scan, iwl_bg_start_internal_scan);
  	INIT_DELAYED_WORK(&priv->scan_check, iwl_bg_scan_check);
  }
  
  void iwl_cancel_scan_deferred_work(struct iwl_priv *priv)
  {
  	cancel_work_sync(&priv->start_internal_scan);
  	cancel_work_sync(&priv->abort_scan);
  	cancel_work_sync(&priv->scan_completed);
  
  	if (cancel_delayed_work_sync(&priv->scan_check)) {
  		mutex_lock(&priv->shrd->mutex);
  		iwl_force_scan_end(priv);
  		mutex_unlock(&priv->shrd->mutex);
  	}
  }
  