slip: Fix use-after-free Read in slip_open

[mirror_ubuntu-jammy-kernel.git] / drivers / net / wireless / intel / iwlwifi / mvm / time-event.c

/******************************************************************************
 *
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * Copyright(c) 2012 - 2014 Intel Corporation. All rights reserved.
 * Copyright(c) 2013 - 2015 Intel Mobile Communications GmbH
 * Copyright(c) 2017 Intel Deutschland GmbH
 * Copyright(c) 2018 - 2019 Intel Corporation
 *
 * 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.
 *
 * The full GNU General Public License is included in this distribution
 * in the file called COPYING.
 *
 * Contact Information:
 *  Intel Linux Wireless <linuxwifi@intel.com>
 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 *
 * BSD LICENSE
 *
 * Copyright(c) 2012 - 2014 Intel Corporation. All rights reserved.
 * Copyright(c) 2013 - 2015 Intel Mobile Communications GmbH
 * Copyright(c) 2017 Intel Deutschland GmbH
 * Copyright(c) 2018 - 2019 Intel Corporation
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *  * Neither the name Intel Corporation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *****************************************************************************/

#include <linux/jiffies.h>
#include <net/mac80211.h>

#include "fw/notif-wait.h"
#include "iwl-trans.h"
#include "fw-api.h"
#include "time-event.h"
#include "mvm.h"
#include "iwl-io.h"
#include "iwl-prph.h"

/*
 * For the high priority TE use a time event type that has similar priority to
 * the FW's action scan priority.
 */
#define IWL_MVM_ROC_TE_TYPE_NORMAL TE_P2P_DEVICE_DISCOVERABLE
#define IWL_MVM_ROC_TE_TYPE_MGMT_TX TE_P2P_CLIENT_ASSOC

void iwl_mvm_te_clear_data(struct iwl_mvm *mvm,
                           struct iwl_mvm_time_event_data *te_data)
{
        lockdep_assert_held(&mvm->time_event_lock);

        if (!te_data || !te_data->vif)
                return;

        list_del(&te_data->list);
        te_data->running = false;
        te_data->uid = 0;
        te_data->id = TE_MAX;
        te_data->vif = NULL;
}

void iwl_mvm_roc_done_wk(struct work_struct *wk)
{
        struct iwl_mvm *mvm = container_of(wk, struct iwl_mvm, roc_done_wk);

        /*
         * Clear the ROC_RUNNING /ROC_AUX_RUNNING status bit.
         * This will cause the TX path to drop offchannel transmissions.
         * That would also be done by mac80211, but it is racy, in particular
         * in the case that the time event actually completed in the firmware
         * (which is handled in iwl_mvm_te_handle_notif).
         */
        clear_bit(IWL_MVM_STATUS_ROC_RUNNING, &mvm->status);
        clear_bit(IWL_MVM_STATUS_ROC_AUX_RUNNING, &mvm->status);

        synchronize_net();

        /*
         * Flush the offchannel queue -- this is called when the time
         * event finishes or is canceled, so that frames queued for it
         * won't get stuck on the queue and be transmitted in the next
         * time event.
         * We have to send the command asynchronously since this cannot
         * be under the mutex for locking reasons, but that's not an
         * issue as it will have to complete before the next command is
         * executed, and a new time event means a new command.
         */
        iwl_mvm_flush_sta(mvm, &mvm->aux_sta, true, CMD_ASYNC);

        /* Do the same for the P2P device queue (STA) */
        if (test_and_clear_bit(IWL_MVM_STATUS_NEED_FLUSH_P2P, &mvm->status)) {
                struct iwl_mvm_vif *mvmvif;

                /*
                 * NB: access to this pointer would be racy, but the flush bit
                 * can only be set when we had a P2P-Device VIF, and we have a
                 * flush of this work in iwl_mvm_prepare_mac_removal() so it's
                 * not really racy.
                 */

                if (!WARN_ON(!mvm->p2p_device_vif)) {
                        mvmvif = iwl_mvm_vif_from_mac80211(mvm->p2p_device_vif);
                        iwl_mvm_flush_sta(mvm, &mvmvif->bcast_sta, true,
                                          CMD_ASYNC);
                }
        }
}

static void iwl_mvm_roc_finished(struct iwl_mvm *mvm)
{
        /*
         * Of course, our status bit is just as racy as mac80211, so in
         * addition, fire off the work struct which will drop all frames
         * from the hardware queues that made it through the race. First
         * it will of course synchronize the TX path to make sure that
         * any *new* TX will be rejected.
         */
        schedule_work(&mvm->roc_done_wk);
}

static void iwl_mvm_csa_noa_start(struct iwl_mvm *mvm)
{
        struct ieee80211_vif *csa_vif;

        rcu_read_lock();

        csa_vif = rcu_dereference(mvm->csa_vif);
        if (!csa_vif || !csa_vif->csa_active)
                goto out_unlock;

        IWL_DEBUG_TE(mvm, "CSA NOA started\n");

        /*
         * CSA NoA is started but we still have beacons to
         * transmit on the current channel.
         * So we just do nothing here and the switch
         * will be performed on the last TBTT.
         */
        if (!ieee80211_csa_is_complete(csa_vif)) {
                IWL_WARN(mvm, "CSA NOA started too early\n");
                goto out_unlock;
        }

        ieee80211_csa_finish(csa_vif);

        rcu_read_unlock();

        RCU_INIT_POINTER(mvm->csa_vif, NULL);

        return;

out_unlock:
        rcu_read_unlock();
}

static bool iwl_mvm_te_check_disconnect(struct iwl_mvm *mvm,
                                        struct ieee80211_vif *vif,
                                        const char *errmsg)
{
        struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);

        if (vif->type != NL80211_IFTYPE_STATION)
                return false;

        if (!mvmvif->csa_bcn_pending && vif->bss_conf.assoc &&
            vif->bss_conf.dtim_period)
                return false;
        if (errmsg)
                IWL_ERR(mvm, "%s\n", errmsg);

        iwl_mvm_connection_loss(mvm, vif, errmsg);
        return true;
}

static void
iwl_mvm_te_handle_notify_csa(struct iwl_mvm *mvm,
                             struct iwl_mvm_time_event_data *te_data,
                             struct iwl_time_event_notif *notif)
{
        struct ieee80211_vif *vif = te_data->vif;
        struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);

        if (!notif->status)
                IWL_DEBUG_TE(mvm, "CSA time event failed to start\n");

        switch (te_data->vif->type) {
        case NL80211_IFTYPE_AP:
                if (!notif->status)
                        mvmvif->csa_failed = true;
                iwl_mvm_csa_noa_start(mvm);
                break;
        case NL80211_IFTYPE_STATION:
                if (!notif->status) {
                        iwl_mvm_connection_loss(mvm, vif,
                                                "CSA TE failed to start");
                        break;
                }
                iwl_mvm_csa_client_absent(mvm, te_data->vif);
                cancel_delayed_work(&mvmvif->csa_work);
                ieee80211_chswitch_done(te_data->vif, true);
                break;
        default:
                /* should never happen */
                WARN_ON_ONCE(1);
                break;
        }

        /* we don't need it anymore */
        iwl_mvm_te_clear_data(mvm, te_data);
}

static void iwl_mvm_te_check_trigger(struct iwl_mvm *mvm,
                                     struct iwl_time_event_notif *notif,
                                     struct iwl_mvm_time_event_data *te_data)
{
        struct iwl_fw_dbg_trigger_tlv *trig;
        struct iwl_fw_dbg_trigger_time_event *te_trig;
        int i;

        trig = iwl_fw_dbg_trigger_on(&mvm->fwrt,
                                     ieee80211_vif_to_wdev(te_data->vif),
                                     FW_DBG_TRIGGER_TIME_EVENT);
        if (!trig)
                return;

        te_trig = (void *)trig->data;

        for (i = 0; i < ARRAY_SIZE(te_trig->time_events); i++) {
                u32 trig_te_id = le32_to_cpu(te_trig->time_events[i].id);
                u32 trig_action_bitmap =
                        le32_to_cpu(te_trig->time_events[i].action_bitmap);
                u32 trig_status_bitmap =
                        le32_to_cpu(te_trig->time_events[i].status_bitmap);

                if (trig_te_id != te_data->id ||
                    !(trig_action_bitmap & le32_to_cpu(notif->action)) ||
                    !(trig_status_bitmap & BIT(le32_to_cpu(notif->status))))
                        continue;

                iwl_fw_dbg_collect_trig(&mvm->fwrt, trig,
                                        "Time event %d Action 0x%x received status: %d",
                                        te_data->id,
                                        le32_to_cpu(notif->action),
                                        le32_to_cpu(notif->status));
                break;
        }
}

/*
 * Handles a FW notification for an event that is known to the driver.
 *
 * @mvm: the mvm component
 * @te_data: the time event data
 * @notif: the notification data corresponding the time event data.
 */
static void iwl_mvm_te_handle_notif(struct iwl_mvm *mvm,
                                    struct iwl_mvm_time_event_data *te_data,
                                    struct iwl_time_event_notif *notif)
{
        lockdep_assert_held(&mvm->time_event_lock);

        IWL_DEBUG_TE(mvm, "Handle time event notif - UID = 0x%x action %d\n",
                     le32_to_cpu(notif->unique_id),
                     le32_to_cpu(notif->action));

        iwl_mvm_te_check_trigger(mvm, notif, te_data);

        /*
         * The FW sends the start/end time event notifications even for events
         * that it fails to schedule. This is indicated in the status field of
         * the notification. This happens in cases that the scheduler cannot
         * find a schedule that can handle the event (for example requesting a
         * P2P Device discoveribility, while there are other higher priority
         * events in the system).
         */
        if (!le32_to_cpu(notif->status)) {
                const char *msg;

                if (notif->action & cpu_to_le32(TE_V2_NOTIF_HOST_EVENT_START))
                        msg = "Time Event start notification failure";
                else
                        msg = "Time Event end notification failure";

                IWL_DEBUG_TE(mvm, "%s\n", msg);

                if (iwl_mvm_te_check_disconnect(mvm, te_data->vif, msg)) {
                        iwl_mvm_te_clear_data(mvm, te_data);
                        return;
                }
        }

        if (le32_to_cpu(notif->action) & TE_V2_NOTIF_HOST_EVENT_END) {
                IWL_DEBUG_TE(mvm,
                             "TE ended - current time %lu, estimated end %lu\n",
                             jiffies, te_data->end_jiffies);

                switch (te_data->vif->type) {
                case NL80211_IFTYPE_P2P_DEVICE:
                        ieee80211_remain_on_channel_expired(mvm->hw);
                        set_bit(IWL_MVM_STATUS_NEED_FLUSH_P2P, &mvm->status);
                        iwl_mvm_roc_finished(mvm);
                        break;
                case NL80211_IFTYPE_STATION:
                        /*
                         * By now, we should have finished association
                         * and know the dtim period.
                         */
                        iwl_mvm_te_check_disconnect(mvm, te_data->vif,
                                "No beacon heard and the time event is over already...");
                        break;
                default:
                        break;
                }

                iwl_mvm_te_clear_data(mvm, te_data);
        } else if (le32_to_cpu(notif->action) & TE_V2_NOTIF_HOST_EVENT_START) {
                te_data->running = true;
                te_data->end_jiffies = TU_TO_EXP_TIME(te_data->duration);

                if (te_data->vif->type == NL80211_IFTYPE_P2P_DEVICE) {
                        set_bit(IWL_MVM_STATUS_ROC_RUNNING, &mvm->status);
                        ieee80211_ready_on_channel(mvm->hw);
                } else if (te_data->id == TE_CHANNEL_SWITCH_PERIOD) {
                        iwl_mvm_te_handle_notify_csa(mvm, te_data, notif);
                }
        } else {
                IWL_WARN(mvm, "Got TE with unknown action\n");
        }
}

/*
 * Handle A Aux ROC time event
 */
static int iwl_mvm_aux_roc_te_handle_notif(struct iwl_mvm *mvm,
                                           struct iwl_time_event_notif *notif)
{
        struct iwl_mvm_time_event_data *te_data, *tmp;
        bool aux_roc_te = false;

        list_for_each_entry_safe(te_data, tmp, &mvm->aux_roc_te_list, list) {
                if (le32_to_cpu(notif->unique_id) == te_data->uid) {
                        aux_roc_te = true;
                        break;
                }
        }
        if (!aux_roc_te) /* Not a Aux ROC time event */
                return -EINVAL;

        iwl_mvm_te_check_trigger(mvm, notif, te_data);

        IWL_DEBUG_TE(mvm,
                     "Aux ROC time event notification  - UID = 0x%x action %d (error = %d)\n",
                     le32_to_cpu(notif->unique_id),
                     le32_to_cpu(notif->action), le32_to_cpu(notif->status));

        if (!le32_to_cpu(notif->status) ||
            le32_to_cpu(notif->action) == TE_V2_NOTIF_HOST_EVENT_END) {
                /* End TE, notify mac80211 */
                ieee80211_remain_on_channel_expired(mvm->hw);
                iwl_mvm_roc_finished(mvm); /* flush aux queue */
                list_del(&te_data->list); /* remove from list */
                te_data->running = false;
                te_data->vif = NULL;
                te_data->uid = 0;
                te_data->id = TE_MAX;
        } else if (le32_to_cpu(notif->action) == TE_V2_NOTIF_HOST_EVENT_START) {
                set_bit(IWL_MVM_STATUS_ROC_AUX_RUNNING, &mvm->status);
                te_data->running = true;
                ieee80211_ready_on_channel(mvm->hw); /* Start TE */
        } else {
                IWL_DEBUG_TE(mvm,
                             "ERROR: Unknown Aux ROC Time Event (action = %d)\n",
                             le32_to_cpu(notif->action));
                return -EINVAL;
        }

        return 0;
}

/*
 * The Rx handler for time event notifications
 */
void iwl_mvm_rx_time_event_notif(struct iwl_mvm *mvm,
                                 struct iwl_rx_cmd_buffer *rxb)
{
        struct iwl_rx_packet *pkt = rxb_addr(rxb);
        struct iwl_time_event_notif *notif = (void *)pkt->data;
        struct iwl_mvm_time_event_data *te_data, *tmp;

        IWL_DEBUG_TE(mvm, "Time event notification - UID = 0x%x action %d\n",
                     le32_to_cpu(notif->unique_id),
                     le32_to_cpu(notif->action));

        spin_lock_bh(&mvm->time_event_lock);
        /* This time event is triggered for Aux ROC request */
        if (!iwl_mvm_aux_roc_te_handle_notif(mvm, notif))
                goto unlock;

        list_for_each_entry_safe(te_data, tmp, &mvm->time_event_list, list) {
                if (le32_to_cpu(notif->unique_id) == te_data->uid)
                        iwl_mvm_te_handle_notif(mvm, te_data, notif);
        }
unlock:
        spin_unlock_bh(&mvm->time_event_lock);
}

static bool iwl_mvm_te_notif(struct iwl_notif_wait_data *notif_wait,
                             struct iwl_rx_packet *pkt, void *data)
{
        struct iwl_mvm *mvm =
                container_of(notif_wait, struct iwl_mvm, notif_wait);
        struct iwl_mvm_time_event_data *te_data = data;
        struct iwl_time_event_notif *resp;
        int resp_len = iwl_rx_packet_payload_len(pkt);

        if (WARN_ON(pkt->hdr.cmd != TIME_EVENT_NOTIFICATION))
                return true;

        if (WARN_ON_ONCE(resp_len != sizeof(*resp))) {
                IWL_ERR(mvm, "Invalid TIME_EVENT_NOTIFICATION response\n");
                return true;
        }

        resp = (void *)pkt->data;

        /* te_data->uid is already set in the TIME_EVENT_CMD response */
        if (le32_to_cpu(resp->unique_id) != te_data->uid)
                return false;

        IWL_DEBUG_TE(mvm, "TIME_EVENT_NOTIFICATION response - UID = 0x%x\n",
                     te_data->uid);
        if (!resp->status)
                IWL_ERR(mvm,
                        "TIME_EVENT_NOTIFICATION received but not executed\n");

        return true;
}

static bool iwl_mvm_time_event_response(struct iwl_notif_wait_data *notif_wait,
                                        struct iwl_rx_packet *pkt, void *data)
{
        struct iwl_mvm *mvm =
                container_of(notif_wait, struct iwl_mvm, notif_wait);
        struct iwl_mvm_time_event_data *te_data = data;
        struct iwl_time_event_resp *resp;
        int resp_len = iwl_rx_packet_payload_len(pkt);

        if (WARN_ON(pkt->hdr.cmd != TIME_EVENT_CMD))
                return true;

        if (WARN_ON_ONCE(resp_len != sizeof(*resp))) {
                IWL_ERR(mvm, "Invalid TIME_EVENT_CMD response\n");
                return true;
        }

        resp = (void *)pkt->data;

        /* we should never get a response to another TIME_EVENT_CMD here */
        if (WARN_ON_ONCE(le32_to_cpu(resp->id) != te_data->id))
                return false;

        te_data->uid = le32_to_cpu(resp->unique_id);
        IWL_DEBUG_TE(mvm, "TIME_EVENT_CMD response - UID = 0x%x\n",
                     te_data->uid);
        return true;
}

static int iwl_mvm_time_event_send_add(struct iwl_mvm *mvm,
                                       struct ieee80211_vif *vif,
                                       struct iwl_mvm_time_event_data *te_data,
                                       struct iwl_time_event_cmd *te_cmd)
{
        static const u16 time_event_response[] = { TIME_EVENT_CMD };
        struct iwl_notification_wait wait_time_event;
        int ret;

        lockdep_assert_held(&mvm->mutex);

        IWL_DEBUG_TE(mvm, "Add new TE, duration %d TU\n",
                     le32_to_cpu(te_cmd->duration));

        spin_lock_bh(&mvm->time_event_lock);
        if (WARN_ON(te_data->id != TE_MAX)) {
                spin_unlock_bh(&mvm->time_event_lock);
                return -EIO;
        }
        te_data->vif = vif;
        te_data->duration = le32_to_cpu(te_cmd->duration);
        te_data->id = le32_to_cpu(te_cmd->id);
        list_add_tail(&te_data->list, &mvm->time_event_list);
        spin_unlock_bh(&mvm->time_event_lock);

        /*
         * Use a notification wait, which really just processes the
         * command response and doesn't wait for anything, in order
         * to be able to process the response and get the UID inside
         * the RX path. Using CMD_WANT_SKB doesn't work because it
         * stores the buffer and then wakes up this thread, by which
         * time another notification (that the time event started)
         * might already be processed unsuccessfully.
         */
        iwl_init_notification_wait(&mvm->notif_wait, &wait_time_event,
                                   time_event_response,
                                   ARRAY_SIZE(time_event_response),
                                   iwl_mvm_time_event_response, te_data);

        ret = iwl_mvm_send_cmd_pdu(mvm, TIME_EVENT_CMD, 0,
                                            sizeof(*te_cmd), te_cmd);
        if (ret) {
                IWL_ERR(mvm, "Couldn't send TIME_EVENT_CMD: %d\n", ret);
                iwl_remove_notification(&mvm->notif_wait, &wait_time_event);
                goto out_clear_te;
        }

        /* No need to wait for anything, so just pass 1 (0 isn't valid) */
        ret = iwl_wait_notification(&mvm->notif_wait, &wait_time_event, 1);
        /* should never fail */
        WARN_ON_ONCE(ret);

        if (ret) {
 out_clear_te:
                spin_lock_bh(&mvm->time_event_lock);
                iwl_mvm_te_clear_data(mvm, te_data);
                spin_unlock_bh(&mvm->time_event_lock);
        }
        return ret;
}

void iwl_mvm_protect_session(struct iwl_mvm *mvm,
                             struct ieee80211_vif *vif,
                             u32 duration, u32 min_duration,
                             u32 max_delay, bool wait_for_notif)
{
        struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
        struct iwl_mvm_time_event_data *te_data = &mvmvif->time_event_data;
        const u16 te_notif_response[] = { TIME_EVENT_NOTIFICATION };
        struct iwl_notification_wait wait_te_notif;
        struct iwl_time_event_cmd time_cmd = {};

        lockdep_assert_held(&mvm->mutex);

        if (te_data->running &&
            time_after(te_data->end_jiffies, TU_TO_EXP_TIME(min_duration))) {
                IWL_DEBUG_TE(mvm, "We have enough time in the current TE: %u\n",
                             jiffies_to_msecs(te_data->end_jiffies - jiffies));
                return;
        }

        if (te_data->running) {
                IWL_DEBUG_TE(mvm, "extend 0x%x: only %u ms left\n",
                             te_data->uid,
                             jiffies_to_msecs(te_data->end_jiffies - jiffies));
                /*
                 * we don't have enough time
                 * cancel the current TE and issue a new one
                 * Of course it would be better to remove the old one only
                 * when the new one is added, but we don't care if we are off
                 * channel for a bit. All we need to do, is not to return
                 * before we actually begin to be on the channel.
                 */
                iwl_mvm_stop_session_protection(mvm, vif);
        }

        time_cmd.action = cpu_to_le32(FW_CTXT_ACTION_ADD);
        time_cmd.id_and_color =
                cpu_to_le32(FW_CMD_ID_AND_COLOR(mvmvif->id, mvmvif->color));
        time_cmd.id = cpu_to_le32(TE_BSS_STA_AGGRESSIVE_ASSOC);

        time_cmd.apply_time = cpu_to_le32(0);

        time_cmd.max_frags = TE_V2_FRAG_NONE;
        time_cmd.max_delay = cpu_to_le32(max_delay);
        /* TODO: why do we need to interval = bi if it is not periodic? */
        time_cmd.interval = cpu_to_le32(1);
        time_cmd.duration = cpu_to_le32(duration);
        time_cmd.repeat = 1;
        time_cmd.policy = cpu_to_le16(TE_V2_NOTIF_HOST_EVENT_START |
                                      TE_V2_NOTIF_HOST_EVENT_END |
                                      TE_V2_START_IMMEDIATELY);

        if (!wait_for_notif) {
                iwl_mvm_time_event_send_add(mvm, vif, te_data, &time_cmd);
                return;
        }

        /*
         * Create notification_wait for the TIME_EVENT_NOTIFICATION to use
         * right after we send the time event
         */
        iwl_init_notification_wait(&mvm->notif_wait, &wait_te_notif,
                                   te_notif_response,
                                   ARRAY_SIZE(te_notif_response),
                                   iwl_mvm_te_notif, te_data);

        /* If TE was sent OK - wait for the notification that started */
        if (iwl_mvm_time_event_send_add(mvm, vif, te_data, &time_cmd)) {
                IWL_ERR(mvm, "Failed to add TE to protect session\n");
                iwl_remove_notification(&mvm->notif_wait, &wait_te_notif);
        } else if (iwl_wait_notification(&mvm->notif_wait, &wait_te_notif,
                                         TU_TO_JIFFIES(max_delay))) {
                IWL_ERR(mvm, "Failed to protect session until TE\n");
        }
}

static bool __iwl_mvm_remove_time_event(struct iwl_mvm *mvm,
                                        struct iwl_mvm_time_event_data *te_data,
                                        u32 *uid)
{
        u32 id;

        /*
         * It is possible that by the time we got to this point the time
         * event was already removed.
         */
        spin_lock_bh(&mvm->time_event_lock);

        /* Save time event uid before clearing its data */
        *uid = te_data->uid;
        id = te_data->id;

        /*
         * The clear_data function handles time events that were already removed
         */
        iwl_mvm_te_clear_data(mvm, te_data);
        spin_unlock_bh(&mvm->time_event_lock);

        /*
         * It is possible that by the time we try to remove it, the time event
         * has already ended and removed. In such a case there is no need to
         * send a removal command.
         */
        if (id == TE_MAX) {
                IWL_DEBUG_TE(mvm, "TE 0x%x has already ended\n", *uid);
                return false;
        }

        return true;
}

/*
 * Explicit request to remove a aux roc time event. The removal of a time
 * event needs to be synchronized with the flow of a time event's end
 * notification, which also removes the time event from the op mode
 * data structures.
 */
static void iwl_mvm_remove_aux_roc_te(struct iwl_mvm *mvm,
                                      struct iwl_mvm_vif *mvmvif,
                                      struct iwl_mvm_time_event_data *te_data)
{
        struct iwl_hs20_roc_req aux_cmd = {};
        u16 len = sizeof(aux_cmd) - iwl_mvm_chan_info_padding(mvm);

        u32 uid;
        int ret;

        if (!__iwl_mvm_remove_time_event(mvm, te_data, &uid))
                return;

        aux_cmd.event_unique_id = cpu_to_le32(uid);
        aux_cmd.action = cpu_to_le32(FW_CTXT_ACTION_REMOVE);
        aux_cmd.id_and_color =
                cpu_to_le32(FW_CMD_ID_AND_COLOR(mvmvif->id, mvmvif->color));
        IWL_DEBUG_TE(mvm, "Removing BSS AUX ROC TE 0x%x\n",
                     le32_to_cpu(aux_cmd.event_unique_id));
        ret = iwl_mvm_send_cmd_pdu(mvm, HOT_SPOT_CMD, 0,
                                   len, &aux_cmd);

        if (WARN_ON(ret))
                return;
}

/*
 * Explicit request to remove a time event. The removal of a time event needs to
 * be synchronized with the flow of a time event's end notification, which also
 * removes the time event from the op mode data structures.
 */
void iwl_mvm_remove_time_event(struct iwl_mvm *mvm,
                               struct iwl_mvm_vif *mvmvif,
                               struct iwl_mvm_time_event_data *te_data)
{
        struct iwl_time_event_cmd time_cmd = {};
        u32 uid;
        int ret;

        if (!__iwl_mvm_remove_time_event(mvm, te_data, &uid))
                return;

        /* When we remove a TE, the UID is to be set in the id field */
        time_cmd.id = cpu_to_le32(uid);
        time_cmd.action = cpu_to_le32(FW_CTXT_ACTION_REMOVE);
        time_cmd.id_and_color =
                cpu_to_le32(FW_CMD_ID_AND_COLOR(mvmvif->id, mvmvif->color));

        IWL_DEBUG_TE(mvm, "Removing TE 0x%x\n", le32_to_cpu(time_cmd.id));
        ret = iwl_mvm_send_cmd_pdu(mvm, TIME_EVENT_CMD, 0,
                                   sizeof(time_cmd), &time_cmd);
        if (WARN_ON(ret))
                return;
}

void iwl_mvm_stop_session_protection(struct iwl_mvm *mvm,
                                     struct ieee80211_vif *vif)
{
        struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
        struct iwl_mvm_time_event_data *te_data = &mvmvif->time_event_data;
        u32 id;

        lockdep_assert_held(&mvm->mutex);

        spin_lock_bh(&mvm->time_event_lock);
        id = te_data->id;
        spin_unlock_bh(&mvm->time_event_lock);

        if (id != TE_BSS_STA_AGGRESSIVE_ASSOC) {
                IWL_DEBUG_TE(mvm,
                             "don't remove TE with id=%u (not session protection)\n",
                             id);
                return;
        }

        iwl_mvm_remove_time_event(mvm, mvmvif, te_data);
}

int iwl_mvm_start_p2p_roc(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
                          int duration, enum ieee80211_roc_type type)
{
        struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
        struct iwl_mvm_time_event_data *te_data = &mvmvif->time_event_data;
        struct iwl_time_event_cmd time_cmd = {};

        lockdep_assert_held(&mvm->mutex);
        if (te_data->running) {
                IWL_WARN(mvm, "P2P_DEVICE remain on channel already running\n");
                return -EBUSY;
        }

        time_cmd.action = cpu_to_le32(FW_CTXT_ACTION_ADD);
        time_cmd.id_and_color =
                cpu_to_le32(FW_CMD_ID_AND_COLOR(mvmvif->id, mvmvif->color));

        switch (type) {
        case IEEE80211_ROC_TYPE_NORMAL:
                time_cmd.id = cpu_to_le32(IWL_MVM_ROC_TE_TYPE_NORMAL);
                break;
        case IEEE80211_ROC_TYPE_MGMT_TX:
                time_cmd.id = cpu_to_le32(IWL_MVM_ROC_TE_TYPE_MGMT_TX);
                break;
        default:
                WARN_ONCE(1, "Got an invalid ROC type\n");
                return -EINVAL;
        }

        time_cmd.apply_time = cpu_to_le32(0);
        time_cmd.interval = cpu_to_le32(1);

        /*
         * The P2P Device TEs can have lower priority than other events
         * that are being scheduled by the driver/fw, and thus it might not be
         * scheduled. To improve the chances of it being scheduled, allow them
         * to be fragmented, and in addition allow them to be delayed.
         */
        time_cmd.max_frags = min(MSEC_TO_TU(duration)/50, TE_V2_FRAG_ENDLESS);
        time_cmd.max_delay = cpu_to_le32(MSEC_TO_TU(duration/2));
        time_cmd.duration = cpu_to_le32(MSEC_TO_TU(duration));
        time_cmd.repeat = 1;
        time_cmd.policy = cpu_to_le16(TE_V2_NOTIF_HOST_EVENT_START |
                                      TE_V2_NOTIF_HOST_EVENT_END |
                                      TE_V2_START_IMMEDIATELY);

        return iwl_mvm_time_event_send_add(mvm, vif, te_data, &time_cmd);
}

static struct iwl_mvm_time_event_data *iwl_mvm_get_roc_te(struct iwl_mvm *mvm)
{
        struct iwl_mvm_time_event_data *te_data;

        lockdep_assert_held(&mvm->mutex);

        spin_lock_bh(&mvm->time_event_lock);

        /*
         * Iterate over the list of time events and find the time event that is
         * associated with a P2P_DEVICE interface.
         * This assumes that a P2P_DEVICE interface can have only a single time
         * event at any given time and this time event coresponds to a ROC
         * request
         */
        list_for_each_entry(te_data, &mvm->time_event_list, list) {
                if (te_data->vif->type == NL80211_IFTYPE_P2P_DEVICE)
                        goto out;
        }

        /* There can only be at most one AUX ROC time event, we just use the
         * list to simplify/unify code. Remove it if it exists.
         */
        te_data = list_first_entry_or_null(&mvm->aux_roc_te_list,
                                           struct iwl_mvm_time_event_data,
                                           list);
out:
        spin_unlock_bh(&mvm->time_event_lock);
        return te_data;
}

void iwl_mvm_cleanup_roc_te(struct iwl_mvm *mvm)
{
        struct iwl_mvm_time_event_data *te_data;
        u32 uid;

        te_data = iwl_mvm_get_roc_te(mvm);
        if (te_data)
                __iwl_mvm_remove_time_event(mvm, te_data, &uid);
}

void iwl_mvm_stop_roc(struct iwl_mvm *mvm)
{
        struct iwl_mvm_vif *mvmvif;
        struct iwl_mvm_time_event_data *te_data;

        te_data = iwl_mvm_get_roc_te(mvm);
        if (!te_data) {
                IWL_WARN(mvm, "No remain on channel event\n");
                return;
        }

        mvmvif = iwl_mvm_vif_from_mac80211(te_data->vif);

        if (te_data->vif->type == NL80211_IFTYPE_P2P_DEVICE) {
                iwl_mvm_remove_time_event(mvm, mvmvif, te_data);
                set_bit(IWL_MVM_STATUS_NEED_FLUSH_P2P, &mvm->status);
        } else {
                iwl_mvm_remove_aux_roc_te(mvm, mvmvif, te_data);
        }

        iwl_mvm_roc_finished(mvm);
}

int iwl_mvm_schedule_csa_period(struct iwl_mvm *mvm,
                                struct ieee80211_vif *vif,
                                u32 duration, u32 apply_time)
{
        struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
        struct iwl_mvm_time_event_data *te_data = &mvmvif->time_event_data;
        struct iwl_time_event_cmd time_cmd = {};

        lockdep_assert_held(&mvm->mutex);

        if (te_data->running) {
                u32 id;

                spin_lock_bh(&mvm->time_event_lock);
                id = te_data->id;
                spin_unlock_bh(&mvm->time_event_lock);

                if (id == TE_CHANNEL_SWITCH_PERIOD) {
                        IWL_DEBUG_TE(mvm, "CS period is already scheduled\n");
                        return -EBUSY;
                }

                /*
                 * Remove the session protection time event to allow the
                 * channel switch. If we got here, we just heard a beacon so
                 * the session protection is not needed anymore anyway.
                 */
                iwl_mvm_remove_time_event(mvm, mvmvif, te_data);
        }

        time_cmd.action = cpu_to_le32(FW_CTXT_ACTION_ADD);
        time_cmd.id_and_color =
                cpu_to_le32(FW_CMD_ID_AND_COLOR(mvmvif->id, mvmvif->color));
        time_cmd.id = cpu_to_le32(TE_CHANNEL_SWITCH_PERIOD);
        time_cmd.apply_time = cpu_to_le32(apply_time);
        time_cmd.max_frags = TE_V2_FRAG_NONE;
        time_cmd.duration = cpu_to_le32(duration);
        time_cmd.repeat = 1;
        time_cmd.interval = cpu_to_le32(1);
        time_cmd.policy = cpu_to_le16(TE_V2_NOTIF_HOST_EVENT_START |
                                      TE_V2_ABSENCE);
        if (!apply_time)
                time_cmd.policy |= cpu_to_le16(TE_V2_START_IMMEDIATELY);

        return iwl_mvm_time_event_send_add(mvm, vif, te_data, &time_cmd);
}