/*
 * Scan implementation for ST-Ericsson CW1200 mac80211 drivers
 *
 * Copyright (c) 2010, ST-Ericsson
 * Author: Dmitry Tarnyagin <dmitry.tarnyagin@lockless.no>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/sched.h>
#include "cw1200.h"
#include "scan.h"
#include "sta.h"
#include "pm.h"

static void cw1200_scan_restart_delayed(struct cw1200_common *priv);

static int cw1200_scan_start(struct cw1200_common *priv, struct wsm_scan *scan)
{
        int ret, i;
        int tmo = 2000;

        switch (priv->join_status) {
        case CW1200_JOIN_STATUS_PRE_STA:
        case CW1200_JOIN_STATUS_JOINING:
                return -EBUSY;
        default:
                break;
        }

        wiphy_dbg(priv->hw->wiphy, "[SCAN] hw req, type %d, %d channels, flags: 0x%x.\n",
                  scan->type, scan->num_channels, scan->flags);

        for (i = 0; i < scan->num_channels; ++i)
                tmo += scan->ch[i].max_chan_time + 10;

        cancel_delayed_work_sync(&priv->clear_recent_scan_work);
        atomic_set(&priv->scan.in_progress, 1);
        atomic_set(&priv->recent_scan, 1);
        cw1200_pm_stay_awake(&priv->pm_state, tmo * HZ / 1000);
        queue_delayed_work(priv->workqueue, &priv->scan.timeout,
                           tmo * HZ / 1000);
        ret = wsm_scan(priv, scan);
        if (ret) {
                atomic_set(&priv->scan.in_progress, 0);
                cancel_delayed_work_sync(&priv->scan.timeout);
                cw1200_scan_restart_delayed(priv);
        }
        return ret;
}

int cw1200_hw_scan(struct ieee80211_hw *hw,
                   struct ieee80211_vif *vif,
                   struct cfg80211_scan_request *req)
{
        struct cw1200_common *priv = hw->priv;
        struct wsm_template_frame frame = {
                .frame_type = WSM_FRAME_TYPE_PROBE_REQUEST,
        };
        int i, ret;

        if (!priv->vif)
                return -EINVAL;

        /* Scan when P2P_GO corrupt firmware MiniAP mode */
        if (priv->join_status == CW1200_JOIN_STATUS_AP)
                return -EOPNOTSUPP;

        if (req->n_ssids == 1 && !req->ssids[0].ssid_len)
                req->n_ssids = 0;

        wiphy_dbg(hw->wiphy, "[SCAN] Scan request for %d SSIDs.\n",
                  req->n_ssids);

        if (req->n_ssids > WSM_SCAN_MAX_NUM_OF_SSIDS)
                return -EINVAL;

        frame.skb = ieee80211_probereq_get(hw, priv->vif, NULL, 0,
                req->ie_len);
        if (!frame.skb)
                return -ENOMEM;

        if (req->ie_len)
                memcpy(skb_put(frame.skb, req->ie_len), req->ie, req->ie_len);

        /* will be unlocked in cw1200_scan_work() */
        down(&priv->scan.lock);
        mutex_lock(&priv->conf_mutex);

        ret = wsm_set_template_frame(priv, &frame);
        if (!ret) {
                /* Host want to be the probe responder. */
                ret = wsm_set_probe_responder(priv, true);
        }
        if (ret) {
                mutex_unlock(&priv->conf_mutex);
                up(&priv->scan.lock);
                dev_kfree_skb(frame.skb);
                return ret;
        }

        wsm_lock_tx(priv);

        BUG_ON(priv->scan.req);
        priv->scan.req = req;
        priv->scan.n_ssids = 0;
        priv->scan.status = 0;
        priv->scan.begin = &req->channels[0];
        priv->scan.curr = priv->scan.begin;
        priv->scan.end = &req->channels[req->n_channels];
        priv->scan.output_power = priv->output_power;

        for (i = 0; i < req->n_ssids; ++i) {
                struct wsm_ssid *dst = &priv->scan.ssids[priv->scan.n_ssids];
                memcpy(&dst->ssid[0], req->ssids[i].ssid, sizeof(dst->ssid));
                dst->length = req->ssids[i].ssid_len;
                ++priv->scan.n_ssids;
        }

        mutex_unlock(&priv->conf_mutex);

        if (frame.skb)
                dev_kfree_skb(frame.skb);
        queue_work(priv->workqueue, &priv->scan.work);
        return 0;
}

void cw1200_scan_work(struct work_struct *work)
{
        struct cw1200_common *priv = container_of(work, struct cw1200_common,
                                                        scan.work);
        struct ieee80211_channel **it;
        struct wsm_scan scan = {
                .type = WSM_SCAN_TYPE_FOREGROUND,
                .flags = WSM_SCAN_FLAG_SPLIT_METHOD,
        };
        bool first_run = (priv->scan.begin == priv->scan.curr &&
                          priv->scan.begin != priv->scan.end);
        int i;

        if (first_run) {
                /* Firmware gets crazy if scan request is sent
                 * when STA is joined but not yet associated.
                 * Force unjoin in this case.
                 */
                if (cancel_delayed_work_sync(&priv->join_timeout) > 0)
                        cw1200_join_timeout(&priv->join_timeout.work);
        }

        mutex_lock(&priv->conf_mutex);

        if (first_run) {
                if (priv->join_status == CW1200_JOIN_STATUS_STA &&
                    !(priv->powersave_mode.mode & WSM_PSM_PS)) {
                        struct wsm_set_pm pm = priv->powersave_mode;
                        pm.mode = WSM_PSM_PS;
                        cw1200_set_pm(priv, &pm);
                } else if (priv->join_status == CW1200_JOIN_STATUS_MONITOR) {
                        /* FW bug: driver has to restart p2p-dev mode
                         * after scan
                         */
                        cw1200_disable_listening(priv);
                }
        }

        if (!priv->scan.req || (priv->scan.curr == priv->scan.end)) {
                if (priv->scan.output_power != priv->output_power)
                        wsm_set_output_power(priv, priv->output_power * 10);
                if (priv->join_status == CW1200_JOIN_STATUS_STA &&
                    !(priv->powersave_mode.mode & WSM_PSM_PS))
                        cw1200_set_pm(priv, &priv->powersave_mode);

                if (priv->scan.status < 0)
                        wiphy_warn(priv->hw->wiphy,
                                   "[SCAN] Scan failed (%d).\n",
                                   priv->scan.status);
                else if (priv->scan.req)
                        wiphy_dbg(priv->hw->wiphy,
                                  "[SCAN] Scan completed.\n");
                else
                        wiphy_dbg(priv->hw->wiphy,
                                  "[SCAN] Scan canceled.\n");

                priv->scan.req = NULL;
                cw1200_scan_restart_delayed(priv);
                wsm_unlock_tx(priv);
                mutex_unlock(&priv->conf_mutex);
                ieee80211_scan_completed(priv->hw, priv->scan.status ? 1 : 0);
                up(&priv->scan.lock);
                return;
        } else {
                struct ieee80211_channel *first = *priv->scan.curr;
                for (it = priv->scan.curr + 1, i = 1;
                     it != priv->scan.end && i < WSM_SCAN_MAX_NUM_OF_CHANNELS;
                     ++it, ++i) {
                        if ((*it)->band != first->band)
                                break;
                        if (((*it)->flags ^ first->flags) &
                                        IEEE80211_CHAN_NO_IR)
                                break;
                        if (!(first->flags & IEEE80211_CHAN_NO_IR) &&
                            (*it)->max_power != first->max_power)
                                break;
                }
                scan.band = first->band;

                if (priv->scan.req->no_cck)
                        scan.max_tx_rate = WSM_TRANSMIT_RATE_6;
                else
                        scan.max_tx_rate = WSM_TRANSMIT_RATE_1;
                scan.num_probes =
                        (first->flags & IEEE80211_CHAN_NO_IR) ? 0 : 2;
                scan.num_ssids = priv->scan.n_ssids;
                scan.ssids = &priv->scan.ssids[0];
                scan.num_channels = it - priv->scan.curr;
                /* TODO: Is it optimal? */
                scan.probe_delay = 100;
                /* It is not stated in WSM specification, however
                 * FW team says that driver may not use FG scan
                 * when joined.
                 */
                if (priv->join_status == CW1200_JOIN_STATUS_STA) {
                        scan.type = WSM_SCAN_TYPE_BACKGROUND;
                        scan.flags = WSM_SCAN_FLAG_FORCE_BACKGROUND;
                }
                scan.ch = kzalloc(
                        sizeof(struct wsm_scan_ch) * (it - priv->scan.curr),
                        GFP_KERNEL);
                if (!scan.ch) {
                        priv->scan.status = -ENOMEM;
                        goto fail;
                }
                for (i = 0; i < scan.num_channels; ++i) {
                        scan.ch[i].number = priv->scan.curr[i]->hw_value;
                        if (priv->scan.curr[i]->flags & IEEE80211_CHAN_NO_IR) {
                                scan.ch[i].min_chan_time = 50;
                                scan.ch[i].max_chan_time = 100;
                        } else {
                                scan.ch[i].min_chan_time = 10;
                                scan.ch[i].max_chan_time = 25;
                        }
                }
                if (!(first->flags & IEEE80211_CHAN_NO_IR) &&
                    priv->scan.output_power != first->max_power) {
                        priv->scan.output_power = first->max_power;
                        wsm_set_output_power(priv,
                                             priv->scan.output_power * 10);
                }
                priv->scan.status = cw1200_scan_start(priv, &scan);
                kfree(scan.ch);
                if (priv->scan.status)
                        goto fail;
                priv->scan.curr = it;
        }
        mutex_unlock(&priv->conf_mutex);
        return;

fail:
        priv->scan.curr = priv->scan.end;
        mutex_unlock(&priv->conf_mutex);
        queue_work(priv->workqueue, &priv->scan.work);
        return;
}

static void cw1200_scan_restart_delayed(struct cw1200_common *priv)
{
        /* FW bug: driver has to restart p2p-dev mode after scan. */
        if (priv->join_status == CW1200_JOIN_STATUS_MONITOR) {
                cw1200_enable_listening(priv);
                cw1200_update_filtering(priv);
        }

        if (priv->delayed_unjoin) {
                priv->delayed_unjoin = false;
                if (queue_work(priv->workqueue, &priv->unjoin_work) <= 0)
                        wsm_unlock_tx(priv);
        } else if (priv->delayed_link_loss) {
                        wiphy_dbg(priv->hw->wiphy, "[CQM] Requeue BSS loss.\n");
                        priv->delayed_link_loss = 0;
                        cw1200_cqm_bssloss_sm(priv, 1, 0, 0);
        }
}

static void cw1200_scan_complete(struct cw1200_common *priv)
{
        queue_delayed_work(priv->workqueue, &priv->clear_recent_scan_work, HZ);
        if (priv->scan.direct_probe) {
                wiphy_dbg(priv->hw->wiphy, "[SCAN] Direct probe complete.\n");
                cw1200_scan_restart_delayed(priv);
                priv->scan.direct_probe = 0;
                up(&priv->scan.lock);
                wsm_unlock_tx(priv);
        } else {
                cw1200_scan_work(&priv->scan.work);
        }
}

void cw1200_scan_failed_cb(struct cw1200_common *priv)
{
        if (priv->mode == NL80211_IFTYPE_UNSPECIFIED)
                /* STA is stopped. */
                return;

        if (cancel_delayed_work_sync(&priv->scan.timeout) > 0) {
                priv->scan.status = -EIO;
                queue_delayed_work(priv->workqueue, &priv->scan.timeout, 0);
        }
}


void cw1200_scan_complete_cb(struct cw1200_common *priv,
                                struct wsm_scan_complete *arg)
{
        if (priv->mode == NL80211_IFTYPE_UNSPECIFIED)
                /* STA is stopped. */
                return;

        if (cancel_delayed_work_sync(&priv->scan.timeout) > 0) {
                priv->scan.status = 1;
                queue_delayed_work(priv->workqueue, &priv->scan.timeout, 0);
        }
}

void cw1200_clear_recent_scan_work(struct work_struct *work)
{
        struct cw1200_common *priv =
                container_of(work, struct cw1200_common,
                             clear_recent_scan_work.work);
        atomic_xchg(&priv->recent_scan, 0);
}

void cw1200_scan_timeout(struct work_struct *work)
{
        struct cw1200_common *priv =
                container_of(work, struct cw1200_common, scan.timeout.work);
        if (atomic_xchg(&priv->scan.in_progress, 0)) {
                if (priv->scan.status > 0) {
                        priv->scan.status = 0;
                } else if (!priv->scan.status) {
                        wiphy_warn(priv->hw->wiphy,
                                   "Timeout waiting for scan complete notification.\n");
                        priv->scan.status = -ETIMEDOUT;
                        priv->scan.curr = priv->scan.end;
                        wsm_stop_scan(priv);
                }
                cw1200_scan_complete(priv);
        }
}

void cw1200_probe_work(struct work_struct *work)
{
        struct cw1200_common *priv =
                container_of(work, struct cw1200_common, scan.probe_work.work);
        u8 queue_id = cw1200_queue_get_queue_id(priv->pending_frame_id);
        struct cw1200_queue *queue = &priv->tx_queue[queue_id];
        const struct cw1200_txpriv *txpriv;
        struct wsm_tx *wsm;
        struct wsm_template_frame frame = {
                .frame_type = WSM_FRAME_TYPE_PROBE_REQUEST,
        };
        struct wsm_ssid ssids[1] = {{
                .length = 0,
        } };
        struct wsm_scan_ch ch[1] = {{
                .min_chan_time = 0,
                .max_chan_time = 10,
        } };
        struct wsm_scan scan = {
                .type = WSM_SCAN_TYPE_FOREGROUND,
                .num_probes = 1,
                .probe_delay = 0,
                .num_channels = 1,
                .ssids = ssids,
                .ch = ch,
        };
        u8 *ies;
        size_t ies_len;
        int ret;

        wiphy_dbg(priv->hw->wiphy, "[SCAN] Direct probe work.\n");

        mutex_lock(&priv->conf_mutex);
        if (down_trylock(&priv->scan.lock)) {
                /* Scan is already in progress. Requeue self. */
                schedule();
                queue_delayed_work(priv->workqueue,
                                   &priv->scan.probe_work, HZ / 10);
                mutex_unlock(&priv->conf_mutex);
                return;
        }

        /* Make sure we still have a pending probe req */
        if (cw1200_queue_get_skb(queue, priv->pending_frame_id,
                                 &frame.skb, &txpriv)) {
                up(&priv->scan.lock);
                mutex_unlock(&priv->conf_mutex);
                wsm_unlock_tx(priv);
                return;
        }
        wsm = (struct wsm_tx *)frame.skb->data;
        scan.max_tx_rate = wsm->max_tx_rate;
        scan.band = (priv->channel->band == IEEE80211_BAND_5GHZ) ?
                WSM_PHY_BAND_5G : WSM_PHY_BAND_2_4G;
        if (priv->join_status == CW1200_JOIN_STATUS_STA ||
            priv->join_status == CW1200_JOIN_STATUS_IBSS) {
                scan.type = WSM_SCAN_TYPE_BACKGROUND;
                scan.flags = WSM_SCAN_FLAG_FORCE_BACKGROUND;
        }
        ch[0].number = priv->channel->hw_value;

        skb_pull(frame.skb, txpriv->offset);

        ies = &frame.skb->data[sizeof(struct ieee80211_hdr_3addr)];
        ies_len = frame.skb->len - sizeof(struct ieee80211_hdr_3addr);

        if (ies_len) {
                u8 *ssidie =
                        (u8 *)cfg80211_find_ie(WLAN_EID_SSID, ies, ies_len);
                if (ssidie && ssidie[1] && ssidie[1] <= sizeof(ssids[0].ssid)) {
                        u8 *nextie = &ssidie[2 + ssidie[1]];
                        /* Remove SSID from the IE list. It has to be provided
                         * as a separate argument in cw1200_scan_start call
                         */

                        /* Store SSID localy */
                        ssids[0].length = ssidie[1];
                        memcpy(ssids[0].ssid, &ssidie[2], ssids[0].length);
                        scan.num_ssids = 1;

                        /* Remove SSID from IE list */
                        ssidie[1] = 0;
                        memmove(&ssidie[2], nextie, &ies[ies_len] - nextie);
                        skb_trim(frame.skb, frame.skb->len - ssids[0].length);
                }
        }

        /* FW bug: driver has to restart p2p-dev mode after scan */
        if (priv->join_status == CW1200_JOIN_STATUS_MONITOR)
                cw1200_disable_listening(priv);
        ret = wsm_set_template_frame(priv, &frame);
        priv->scan.direct_probe = 1;
        if (!ret) {
                wsm_flush_tx(priv);
                ret = cw1200_scan_start(priv, &scan);
        }
        mutex_unlock(&priv->conf_mutex);

        skb_push(frame.skb, txpriv->offset);
        if (!ret)
                IEEE80211_SKB_CB(frame.skb)->flags |= IEEE80211_TX_STAT_ACK;
        BUG_ON(cw1200_queue_remove(queue, priv->pending_frame_id));

        if (ret) {
                priv->scan.direct_probe = 0;
                up(&priv->scan.lock);
                wsm_unlock_tx(priv);
        }

        return;
}