/******************************************************************************
 *
 * GPL LICENSE SUMMARY
 *
 * Copyright(c) 2008 - 2009 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/types.h>
#include <linux/etherdevice.h>
#include <net/lib80211.h>
#include <net/mac80211.h>

#include "iwl-eeprom.h"
#include "iwl-dev.h"
#include "iwl-core.h"
#include "iwl-sta.h"
#include "iwl-io.h"
#include "iwl-helpers.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



/**
 * iwl_scan_cancel - Cancel any currently executing HW scan
 *
 * NOTE: priv->mutex is not required before calling this function
 */
int iwl_scan_cancel(struct iwl_priv *priv)
{
        if (!test_bit(STATUS_SCAN_HW, &priv->status)) {
                clear_bit(STATUS_SCANNING, &priv->status);
                return 0;
        }

        if (test_bit(STATUS_SCANNING, &priv->status)) {
                if (!test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
                        IWL_DEBUG_SCAN(priv, "Queuing scan abort.\n");
                        set_bit(STATUS_SCAN_ABORTING, &priv->status);
                        queue_work(priv->workqueue, &priv->abort_scan);

                } else
                        IWL_DEBUG_SCAN(priv, "Scan abort already in progress.\n");

                return test_bit(STATUS_SCANNING, &priv->status);
        }

        return 0;
}
EXPORT_SYMBOL(iwl_scan_cancel);
/**
 * iwl_scan_cancel_timeout - Cancel any currently executing HW scan
 * @ms: amount of time to wait (in milliseconds) for scan to abort
 *
 * NOTE: priv->mutex must be held before calling this function
 */
int iwl_scan_cancel_timeout(struct iwl_priv *priv, unsigned long ms)
{
        unsigned long now = jiffies;
        int ret;

        ret = iwl_scan_cancel(priv);
        if (ret && ms) {
                mutex_unlock(&priv->mutex);
                while (!time_after(jiffies, now + msecs_to_jiffies(ms)) &&
                                test_bit(STATUS_SCANNING, &priv->status))
                        msleep(1);
                mutex_lock(&priv->mutex);

                return test_bit(STATUS_SCANNING, &priv->status);
        }

        return ret;
}
EXPORT_SYMBOL(iwl_scan_cancel_timeout);

static int iwl_send_scan_abort(struct iwl_priv *priv)
{
        int ret = 0;
        struct iwl_rx_packet *res;
        struct iwl_host_cmd cmd = {
                .id = REPLY_SCAN_ABORT_CMD,
                .flags = CMD_WANT_SKB,
        };

        /* If there isn't a scan actively going on in the hardware
         * then we are in between scan bands and not actually
         * actively scanning, so don't send the abort command */
        if (!test_bit(STATUS_SCAN_HW, &priv->status)) {
                clear_bit(STATUS_SCAN_ABORTING, &priv->status);
                return 0;
        }

        ret = iwl_send_cmd_sync(priv, &cmd);
        if (ret) {
                clear_bit(STATUS_SCAN_ABORTING, &priv->status);
                return ret;
        }

        res = (struct iwl_rx_packet *)cmd.reply_skb->data;
        if (res->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_INFO(priv, "SCAN_ABORT returned %d.\n", res->u.status);
                clear_bit(STATUS_SCAN_ABORTING, &priv->status);
                clear_bit(STATUS_SCAN_HW, &priv->status);
        }

        priv->alloc_rxb_skb--;
        dev_kfree_skb_any(cmd.reply_skb);

        return ret;
}

/* Service response to REPLY_SCAN_CMD (0x80) */
static void iwl_rx_reply_scan(struct iwl_priv *priv,
                              struct iwl_rx_mem_buffer *rxb)
{
#ifdef CONFIG_IWLWIFI_DEBUG
        struct iwl_rx_packet *pkt = (struct iwl_rx_packet *)rxb->skb->data;
        struct iwl_scanreq_notification *notif =
            (struct iwl_scanreq_notification *)pkt->u.raw;

        IWL_DEBUG_RX(priv, "Scan request status = 0x%x\n", notif->status);
#endif
}

/* Service SCAN_START_NOTIFICATION (0x82) */
static void iwl_rx_scan_start_notif(struct iwl_priv *priv,
                                    struct iwl_rx_mem_buffer *rxb)
{
        struct iwl_rx_packet *pkt = (struct iwl_rx_packet *)rxb->skb->data;
        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);
}

/* Service SCAN_RESULTS_NOTIFICATION (0x83) */
static void iwl_rx_scan_results_notif(struct iwl_priv *priv,
                                      struct iwl_rx_mem_buffer *rxb)
{
#ifdef CONFIG_IWLWIFI_DEBUG
        struct iwl_rx_packet *pkt = (struct iwl_rx_packet *)rxb->skb->data;
        struct iwl_scanresults_notification *notif =
            (struct iwl_scanresults_notification *)pkt->u.raw;

        IWL_DEBUG_SCAN(priv, "Scan ch.res: "
                       "%d [802.11%s] "
                       "(TSF: 0x%08X:%08X) - %d "
                       "elapsed=%lu usec (%dms since last)\n",
                       notif->channel,
                       notif->band ? "bg" : "a",
                       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,
                       jiffies_to_msecs(elapsed_jiffies
                                        (priv->last_scan_jiffies, jiffies)));
#endif

        priv->last_scan_jiffies = jiffies;
        priv->next_scan_jiffies = 0;
}

/* Service SCAN_COMPLETE_NOTIFICATION (0x84) */
static void iwl_rx_scan_complete_notif(struct iwl_priv *priv,
                                       struct iwl_rx_mem_buffer *rxb)
{
#ifdef CONFIG_IWLWIFI_DEBUG
        struct iwl_rx_packet *pkt = (struct iwl_rx_packet *)rxb->skb->data;
        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);
#endif

        /* The HW is no longer scanning */
        clear_bit(STATUS_SCAN_HW, &priv->status);

        IWL_DEBUG_INFO(priv, "Scan pass on %sGHz took %dms\n",
                       (priv->scan_bands & BIT(IEEE80211_BAND_2GHZ)) ?
                                                "2.4" : "5.2",
                       jiffies_to_msecs(elapsed_jiffies
                                        (priv->scan_pass_start, jiffies)));

        /* Remove this scanned band from the list of pending
         * bands to scan, band G precedes A in order of scanning
         * as seen in iwl_bg_request_scan */
        if (priv->scan_bands & BIT(IEEE80211_BAND_2GHZ))
                priv->scan_bands &= ~BIT(IEEE80211_BAND_2GHZ);
        else if (priv->scan_bands &  BIT(IEEE80211_BAND_5GHZ))
                priv->scan_bands &= ~BIT(IEEE80211_BAND_5GHZ);

        /* If a request to abort was given, or the scan did not succeed
         * then we reset the scan state machine and terminate,
         * re-queuing another scan if one has been requested */
        if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
                IWL_DEBUG_INFO(priv, "Aborted scan completed.\n");
                clear_bit(STATUS_SCAN_ABORTING, &priv->status);
        } else {
                /* If there are more bands on this scan pass reschedule */
                if (priv->scan_bands)
                        goto reschedule;
        }

        priv->last_scan_jiffies = jiffies;
        priv->next_scan_jiffies = 0;
        IWL_DEBUG_INFO(priv, "Setting scan to off\n");

        clear_bit(STATUS_SCANNING, &priv->status);

        IWL_DEBUG_INFO(priv, "Scan took %dms\n",
                jiffies_to_msecs(elapsed_jiffies(priv->scan_start, jiffies)));

        queue_work(priv->workqueue, &priv->scan_completed);

        return;

reschedule:
        priv->scan_pass_start = jiffies;
        queue_work(priv->workqueue, &priv->request_scan);
}

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;
}
EXPORT_SYMBOL(iwl_setup_rx_scan_handlers);

inline 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);
}
EXPORT_SYMBOL(iwl_get_active_dwell_time);

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;

        if (iwl_is_associated(priv)) {
                /* If we're associated, we clamp the maximum passive
                 * dwell time to be 98% of the beacon interval (minus
                 * 2 * channel tune time) */
                passive = priv->beacon_int;
                if ((passive > IWL_PASSIVE_DWELL_BASE) || !passive)
                        passive = IWL_PASSIVE_DWELL_BASE;
                passive = (passive * 98) / 100 - IWL_CHANNEL_TUNE_TIME * 2;
        }

        return passive;
}
EXPORT_SYMBOL(iwl_get_passive_dwell_time);

static int iwl_get_channels_for_scan(struct iwl_priv *priv,
                                     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 = ieee80211_frequency_to_channel(chan->center_freq);
                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;
}

void iwl_init_scan_params(struct iwl_priv *priv)
{
        u8 ant_idx = fls(priv->hw_params.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;
}

static int iwl_scan_initiate(struct iwl_priv *priv)
{
        if (!iwl_is_ready_rf(priv)) {
                IWL_DEBUG_SCAN(priv, "Aborting scan due to not ready.\n");
                return -EIO;
        }

        if (test_bit(STATUS_SCANNING, &priv->status)) {
                IWL_DEBUG_SCAN(priv, "Scan already in progress.\n");
                return -EAGAIN;
        }

        if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
                IWL_DEBUG_SCAN(priv, "Scan request while abort pending\n");
                return -EAGAIN;
        }

        IWL_DEBUG_INFO(priv, "Starting scan...\n");
        set_bit(STATUS_SCANNING, &priv->status);
        priv->scan_start = jiffies;
        priv->scan_pass_start = priv->scan_start;

        queue_work(priv->workqueue, &priv->request_scan);

        return 0;
}

#define IWL_DELAY_NEXT_SCAN (HZ*2)

int iwl_mac_hw_scan(struct ieee80211_hw *hw,
                     struct cfg80211_scan_request *req)
{
        unsigned long flags;
        struct iwl_priv *priv = hw->priv;
        int ret, i;

        IWL_DEBUG_MAC80211(priv, "enter\n");

        mutex_lock(&priv->mutex);
        spin_lock_irqsave(&priv->lock, flags);

        if (!iwl_is_ready_rf(priv)) {
                ret = -EIO;
                IWL_DEBUG_MAC80211(priv, "leave - not ready or exit pending\n");
                goto out_unlock;
        }

        /* We don't schedule scan within next_scan_jiffies period.
         * Avoid scanning during possible EAPOL exchange, return
         * success immediately.
         */
        if (priv->next_scan_jiffies &&
            time_after(priv->next_scan_jiffies, jiffies)) {
                IWL_DEBUG_SCAN(priv, "scan rejected: within next scan period\n");
                queue_work(priv->workqueue, &priv->scan_completed);
                ret = 0;
                goto out_unlock;
        }

        /* if we just finished scan ask for delay */
        if (iwl_is_associated(priv) && priv->last_scan_jiffies &&
            time_after(priv->last_scan_jiffies + IWL_DELAY_NEXT_SCAN, jiffies)) {
                IWL_DEBUG_SCAN(priv, "scan rejected: within previous scan period\n");
                queue_work(priv->workqueue, &priv->scan_completed);
                ret = 0;
                goto out_unlock;
        }

        priv->scan_bands = 0;
        for (i = 0; i < req->n_channels; i++)
                priv->scan_bands |= BIT(req->channels[i]->band);

        priv->scan_request = req;

        ret = iwl_scan_initiate(priv);

        IWL_DEBUG_MAC80211(priv, "leave\n");

out_unlock:
        spin_unlock_irqrestore(&priv->lock, flags);
        mutex_unlock(&priv->mutex);

        return ret;
}
EXPORT_SYMBOL(iwl_mac_hw_scan);

#define IWL_SCAN_CHECK_WATCHDOG (7 * HZ)

void iwl_bg_scan_check(struct work_struct *data)
{
        struct iwl_priv *priv =
            container_of(data, struct iwl_priv, scan_check.work);

        if (test_bit(STATUS_EXIT_PENDING, &priv->status))
                return;

        mutex_lock(&priv->mutex);
        if (test_bit(STATUS_SCANNING, &priv->status) ||
            test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
                IWL_DEBUG_SCAN(priv, "Scan completion watchdog resetting "
                        "adapter (%dms)\n",
                        jiffies_to_msecs(IWL_SCAN_CHECK_WATCHDOG));

                if (!test_bit(STATUS_EXIT_PENDING, &priv->status))
                        iwl_send_scan_abort(priv);
        }
        mutex_unlock(&priv->mutex);
}
EXPORT_SYMBOL(iwl_bg_scan_check);

/**
 * 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 *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, priv->mac_addr, 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;

        memcpy(pos, ies, ie_len);
        len += ie_len;
        left -= ie_len;

        return (u16)len;
}
EXPORT_SYMBOL(iwl_fill_probe_req);

static void iwl_bg_request_scan(struct work_struct *data)
{
        struct iwl_priv *priv =
            container_of(data, struct iwl_priv, request_scan);
        struct iwl_host_cmd cmd = {
                .id = REPLY_SCAN_CMD,
                .len = sizeof(struct iwl_scan_cmd),
                .flags = CMD_SIZE_HUGE,
        };
        struct iwl_scan_cmd *scan;
        struct ieee80211_conf *conf = NULL;
        int ret = 0;
        u32 rate_flags = 0;
        u16 cmd_len;
        u16 rx_chain = 0;
        enum ieee80211_band band;
        u8 n_probes = 0;
        u8 rx_ant = priv->hw_params.valid_rx_ant;
        u8 rate;
        bool is_active = false;
        int  chan_mod;

        conf = ieee80211_get_hw_conf(priv->hw);

        mutex_lock(&priv->mutex);

        cancel_delayed_work(&priv->scan_check);

        if (!iwl_is_ready(priv)) {
                IWL_WARN(priv, "request scan called when driver not ready.\n");
                goto done;
        }

        /* Make sure the scan wasn't canceled before this queued work
         * was given the chance to run... */
        if (!test_bit(STATUS_SCANNING, &priv->status))
                goto done;

        /* This should never be called or scheduled if there is currently
         * a scan active in the hardware. */
        if (test_bit(STATUS_SCAN_HW, &priv->status)) {
                IWL_DEBUG_INFO(priv, "Multiple concurrent scan requests in parallel. "
                               "Ignoring second request.\n");
                ret = -EIO;
                goto done;
        }

        if (test_bit(STATUS_EXIT_PENDING, &priv->status)) {
                IWL_DEBUG_SCAN(priv, "Aborting scan due to device shutdown\n");
                goto done;
        }

        if (test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
                IWL_DEBUG_HC(priv, "Scan request while abort pending.  Queuing.\n");
                goto done;
        }

        if (iwl_is_rfkill(priv)) {
                IWL_DEBUG_HC(priv, "Aborting scan due to RF Kill activation\n");
                goto done;
        }

        if (!test_bit(STATUS_READY, &priv->status)) {
                IWL_DEBUG_HC(priv, "Scan request while uninitialized.  Queuing.\n");
                goto done;
        }

        if (!priv->scan_bands) {
                IWL_DEBUG_HC(priv, "Aborting scan due to no requested bands\n");
                goto done;
        }

        if (!priv->scan) {
                priv->scan = kmalloc(sizeof(struct iwl_scan_cmd) +
                                     IWL_MAX_SCAN_SIZE, GFP_KERNEL);
                if (!priv->scan) {
                        ret = -ENOMEM;
                        goto done;
                }
        }
        scan = priv->scan;
        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 (iwl_is_associated(priv)) {
                u16 interval = 0;
                u32 extra;
                u32 suspend_time = 100;
                u32 scan_suspend_time = 100;
                unsigned long flags;

                IWL_DEBUG_INFO(priv, "Scanning while associated...\n");

                spin_lock_irqsave(&priv->lock, flags);
                interval = priv->beacon_int;
                spin_unlock_irqrestore(&priv->lock, flags);

                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);
        }

        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");

        scan->tx_cmd.tx_flags = TX_CMD_FLG_SEQ_CTL_MSK;
        scan->tx_cmd.sta_id = priv->hw_params.bcast_sta_id;
        scan->tx_cmd.stop_time.life_time = TX_CMD_LIFE_TIME_INFINITE;


        if (priv->scan_bands & BIT(IEEE80211_BAND_2GHZ)) {
                band = IEEE80211_BAND_2GHZ;
                scan->flags = RXON_FLG_BAND_24G_MSK | RXON_FLG_AUTO_DETECT_MSK;
                chan_mod = le32_to_cpu(priv->active_rxon.flags & RXON_FLG_CHANNEL_MODE_MSK)
                                       >> RXON_FLG_CHANNEL_MODE_POS;
                if (chan_mod == CHANNEL_MODE_PURE_40) {
                        rate = IWL_RATE_6M_PLCP;
                } else {
                        rate = IWL_RATE_1M_PLCP;
                        rate_flags = RATE_MCS_CCK_MSK;
                }
                scan->good_CRC_th = 0;
        } else if (priv->scan_bands & BIT(IEEE80211_BAND_5GHZ)) {
                band = IEEE80211_BAND_5GHZ;
                rate = IWL_RATE_6M_PLCP;
                /*
                 * If active scaning is requested but a certain channel
                 * is marked passive, we can do active scanning if we
                 * detect transmissions.
                 */
                scan->good_CRC_th = is_active ? IWL_GOOD_CRC_TH : 0;

                /* Force use of chains B and C (0x6) for scan Rx for 4965
                 * Avoid A (0x1) because of its off-channel reception on A-band.
                 */
                if ((priv->hw_rev & CSR_HW_REV_TYPE_MSK) == CSR_HW_REV_TYPE_4965)
                        rx_ant = ANT_BC;
        } else {
                IWL_WARN(priv, "Invalid scan band count\n");
                goto done;
        }

        priv->scan_tx_ant[band] =
                         iwl_toggle_tx_ant(priv, priv->scan_tx_ant[band]);
        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);

        /* MIMO is not used here, but value is required */
        rx_chain |= ANT_ABC << RXON_RX_CHAIN_VALID_POS;
        rx_chain |= ANT_ABC << 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);
        cmd_len = iwl_fill_probe_req(priv,
                                (struct ieee80211_mgmt *)scan->data,
                                priv->scan_request->ie,
                                priv->scan_request->ie_len,
                                IWL_MAX_SCAN_SIZE - sizeof(*scan));

        scan->tx_cmd.len = cpu_to_le16(cmd_len);

        if (iwl_is_monitor_mode(priv))
                scan->filter_flags = RXON_FILTER_PROMISC_MSK;

        scan->filter_flags |= (RXON_FILTER_ACCEPT_GRP_MSK |
                               RXON_FILTER_BCON_AWARE_MSK);

        scan->channel_count =
                iwl_get_channels_for_scan(priv, band, is_active, n_probes,
                        (void *)&scan->data[le16_to_cpu(scan->tx_cmd.len)]);

        if (scan->channel_count == 0) {
                IWL_DEBUG_SCAN(priv, "channel count %d\n", scan->channel_count);
                goto done;
        }

        cmd.len += le16_to_cpu(scan->tx_cmd.len) +
            scan->channel_count * sizeof(struct iwl_scan_channel);
        cmd.data = scan;
        scan->len = cpu_to_le16(cmd.len);

        set_bit(STATUS_SCAN_HW, &priv->status);
        ret = iwl_send_cmd_sync(priv, &cmd);
        if (ret)
                goto done;

        queue_delayed_work(priv->workqueue, &priv->scan_check,
                           IWL_SCAN_CHECK_WATCHDOG);

        mutex_unlock(&priv->mutex);
        return;

 done:
        /* Cannot perform scan. Make sure we clear scanning
        * bits from status so next scan request can be performed.
        * If we don't clear scanning status bit here all next scan
        * will fail
        */
        clear_bit(STATUS_SCAN_HW, &priv->status);
        clear_bit(STATUS_SCANNING, &priv->status);
        /* inform mac80211 scan aborted */
        queue_work(priv->workqueue, &priv->scan_completed);
        mutex_unlock(&priv->mutex);
}

void iwl_bg_abort_scan(struct work_struct *work)
{
        struct iwl_priv *priv = container_of(work, struct iwl_priv, abort_scan);

        if (!test_bit(STATUS_READY, &priv->status) ||
            !test_bit(STATUS_GEO_CONFIGURED, &priv->status))
                return;

        mutex_lock(&priv->mutex);

        set_bit(STATUS_SCAN_ABORTING, &priv->status);
        iwl_send_scan_abort(priv);

        mutex_unlock(&priv->mutex);
}
EXPORT_SYMBOL(iwl_bg_abort_scan);

void iwl_bg_scan_completed(struct work_struct *work)
{
        struct iwl_priv *priv =
            container_of(work, struct iwl_priv, scan_completed);

        IWL_DEBUG_SCAN(priv, "SCAN complete scan\n");

        cancel_delayed_work(&priv->scan_check);

        ieee80211_scan_completed(priv->hw, false);

        if (test_bit(STATUS_EXIT_PENDING, &priv->status))
                return;

        /* Since setting the TXPOWER may have been deferred while
         * performing the scan, fire one off */
        mutex_lock(&priv->mutex);
        iwl_set_tx_power(priv, priv->tx_power_user_lmt, true);
        mutex_unlock(&priv->mutex);
}
EXPORT_SYMBOL(iwl_bg_scan_completed);

void iwl_setup_scan_deferred_work(struct iwl_priv *priv)
{
        INIT_WORK(&priv->scan_completed, iwl_bg_scan_completed);
        INIT_WORK(&priv->request_scan, iwl_bg_request_scan);
        INIT_WORK(&priv->abort_scan, iwl_bg_abort_scan);
        INIT_DELAYED_WORK(&priv->scan_check, iwl_bg_scan_check);
}
EXPORT_SYMBOL(iwl_setup_scan_deferred_work);