iwl3945: Use iwlcore scan code

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / net / wireless / iwlwifi / iwl-scan.c

/******************************************************************************
 *
 * 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("Queuing scan abort.\n");
                        set_bit(STATUS_SCAN_ABORTING, &priv->status);
                        queue_work(priv->workqueue, &priv->abort_scan);

                } else
                        IWL_DEBUG_SCAN("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,
                .meta.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.meta.u.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("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.meta.u.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("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("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("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("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);

        /* The scan completion notification came in, so kill that timer... */
        cancel_delayed_work(&priv->scan_check);

        IWL_DEBUG_INFO("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("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("Setting scan to off\n");

        clear_bit(STATUS_SCANNING, &priv->status);

        IWL_DEBUG_INFO("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)
{
        const struct ieee80211_channel *channels = NULL;
        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;

        channels = sband->channels;

        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 < sband->n_channels; i++) {
                if (channels[i].flags & IEEE80211_CHAN_DISABLED)
                        continue;

                channel =
                        ieee80211_frequency_to_channel(channels[i].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("Channel %d is INVALID for this band.\n",
                                        channel);
                        continue;
                }

                if (!is_active || is_channel_passive(ch_info) ||
                    (channels[i].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("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("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;
}

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

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

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

        IWL_DEBUG_INFO("Starting scan...\n");
        if (priv->cfg->sku & IWL_SKU_G)
                priv->scan_bands |= BIT(IEEE80211_BAND_2GHZ);
        if (priv->cfg->sku & IWL_SKU_A)
                priv->scan_bands |= BIT(IEEE80211_BAND_5GHZ);
        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;
}
EXPORT_SYMBOL(iwl_scan_initiate);

#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(IWL_DL_SCAN, "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_supported_rate_to_ie - fill in the supported rate in IE field
 *
 * return : set the bit for each supported rate insert in ie
 */
static u16 iwl_supported_rate_to_ie(u8 *ie, u16 supported_rate,
                                    u16 basic_rate, int *left)
{
        u16 ret_rates = 0, bit;
        int i;
        u8 *cnt = ie;
        u8 *rates = ie + 1;

        for (bit = 1, i = 0; i < IWL_RATE_COUNT; i++, bit <<= 1) {
                if (bit & supported_rate) {
                        ret_rates |= bit;
                        rates[*cnt] = iwl_rates[i].ieee |
                                ((bit & basic_rate) ? 0x80 : 0x00);
                        (*cnt)++;
                        (*left)--;
                        if ((*left <= 0) ||
                            (*cnt >= IWL_SUPPORTED_RATES_IE_LEN))
                                break;
                }
        }

        return ret_rates;
}


static void iwl_ht_cap_to_ie(const struct ieee80211_supported_band *sband,
                             u8 *pos, int *left)
{
        struct ieee80211_ht_cap *ht_cap;

        if (!sband || !sband->ht_cap.ht_supported)
                return;

        if (*left < sizeof(struct ieee80211_ht_cap))
                return;

        *pos++ = sizeof(struct ieee80211_ht_cap);
        ht_cap = (struct ieee80211_ht_cap *) pos;

        ht_cap->cap_info = cpu_to_le16(sband->ht_cap.cap);
        memcpy(&ht_cap->mcs, &sband->ht_cap.mcs, 16);
        ht_cap->ampdu_params_info =
                (sband->ht_cap.ampdu_factor & IEEE80211_HT_AMPDU_PARM_FACTOR) |
                ((sband->ht_cap.ampdu_density << 2) &
                        IEEE80211_HT_AMPDU_PARM_DENSITY);
        *left -= sizeof(struct ieee80211_ht_cap);
}

/**
 * iwl_fill_probe_req - fill in all required fields and IE for probe request
 */

u16 iwl_fill_probe_req(struct iwl_priv *priv,
                       enum ieee80211_band band,
                       struct ieee80211_mgmt *frame,
                       int left)
{
        int len = 0;
        u8 *pos = NULL;
        u16 active_rates, ret_rates, cck_rates, active_rate_basic;
        const struct ieee80211_supported_band *sband =
                                                iwl_get_hw_mode(priv, band);


        /* 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;

        /* fill in supported rate */
        left -= 2;
        if (left < 0)
                return 0;

        *pos++ = WLAN_EID_SUPP_RATES;
        *pos = 0;

        /* exclude 60M rate */
        active_rates = priv->rates_mask;
        active_rates &= ~IWL_RATE_60M_MASK;

        active_rate_basic = active_rates & IWL_BASIC_RATES_MASK;

        cck_rates = IWL_CCK_RATES_MASK & active_rates;
        ret_rates = iwl_supported_rate_to_ie(pos, cck_rates,
                                             active_rate_basic, &left);
        active_rates &= ~ret_rates;

        ret_rates = iwl_supported_rate_to_ie(pos, active_rates,
                                             active_rate_basic, &left);
        active_rates &= ~ret_rates;

        len += 2 + *pos;
        pos += (*pos) + 1;

        if (active_rates == 0)
                goto fill_end;

        /* fill in supported extended rate */
        /* ...next IE... */
        left -= 2;
        if (left < 0)
                return 0;
        /* ... fill it in... */
        *pos++ = WLAN_EID_EXT_SUPP_RATES;
        *pos = 0;
        iwl_supported_rate_to_ie(pos, active_rates, active_rate_basic, &left);
        if (*pos > 0) {
                len += 2 + *pos;
                pos += (*pos) + 1;
        } else {
                pos--;
        }

 fill_end:

        left -= 2;
        if (left < 0)
                return 0;

        *pos++ = WLAN_EID_HT_CAPABILITY;
        *pos = 0;
        iwl_ht_cap_to_ie(sband, pos, &left);
        if (*pos > 0)
                len += 2 + *pos;

        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),
                .meta.flags = CMD_SIZE_HUGE,
        };
        struct iwl_scan_cmd *scan;
        struct ieee80211_conf *conf = NULL;
        int ret = 0;
        u32 rate_flags = 0;
        u16 cmd_len;
        enum ieee80211_band band;
        u8 n_probes = 2;
        u8 rx_chain = priv->hw_params.valid_rx_ant;
        u8 rate;
        DECLARE_SSID_BUF(ssid);

        conf = ieee80211_get_hw_conf(priv->hw);

        mutex_lock(&priv->mutex);

        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("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("Aborting scan due to device shutdown\n");
                goto done;
        }

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

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

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

        if (!priv->scan_bands) {
                IWL_DEBUG_HC("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("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("suspend_time 0x%X beacon interval %d\n",
                               scan_suspend_time, interval);
        }

        /* We should add the ability for user to lock to PASSIVE ONLY */
        if (priv->one_direct_scan) {
                IWL_DEBUG_SCAN("Start direct scan for '%s'\n",
                                print_ssid(ssid, priv->direct_ssid,
                                           priv->direct_ssid_len));
                scan->direct_scan[0].id = WLAN_EID_SSID;
                scan->direct_scan[0].len = priv->direct_ssid_len;
                memcpy(scan->direct_scan[0].ssid,
                       priv->direct_ssid, priv->direct_ssid_len);
                n_probes++;
        } else {
                IWL_DEBUG_SCAN("Start indirect 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;
                if (priv->active_rxon.flags & RXON_FLG_CHANNEL_MODE_PURE_40_MSK) {
                        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;
                scan->good_CRC_th = IWL_GOOD_CRC_TH;

                /* 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_chain = 0x6;
        } 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 */
        scan->rx_chain = RXON_RX_CHAIN_DRIVER_FORCE_MSK |
                                cpu_to_le16((0x7 << RXON_RX_CHAIN_VALID_POS) |
                                (rx_chain << RXON_RX_CHAIN_FORCE_SEL_POS) |
                                (0x7 << RXON_RX_CHAIN_FORCE_MIMO_SEL_POS));

        cmd_len = iwl_fill_probe_req(priv, band,
                                     (struct ieee80211_mgmt *)scan->data,
                                     IWL_MAX_SCAN_SIZE - sizeof(*scan));

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

        if (priv->iw_mode == NL80211_IFTYPE_MONITOR)
                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, 1, /* active */
                        n_probes,
                        (void *)&scan->data[le16_to_cpu(scan->tx_cmd.len)]);

        if (scan->channel_count == 0) {
                IWL_DEBUG_SCAN("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 (!iwl_is_ready(priv))
                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("SCAN complete scan\n");

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

        ieee80211_scan_completed(priv->hw);

        /* 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);