linux_kernel/drivers/net/wireless/iwlwifi/mvm/tdls.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) 2014 Intel Mobile Communications GmbH
 *
 * 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 COPYING.
 *
 * Contact Information:
 *  Intel Linux Wireless <ilw@linux.intel.com>
 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
 *
 * BSD LICENSE
 *
 * Copyright(c) 2014 Intel Mobile Communications GmbH
 * 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/etherdevice.h>
#include "mvm.h"
#include "time-event.h"

#define TU_TO_US(x) (x * 1024)
#define TU_TO_MS(x) (TU_TO_US(x) / 1000)

void iwl_mvm_teardown_tdls_peers(struct iwl_mvm *mvm)
{
	struct ieee80211_sta *sta;
	struct iwl_mvm_sta *mvmsta;
	int i;

	lockdep_assert_held(&mvm->mutex);

	for (i = 0; i < IWL_MVM_STATION_COUNT; i++) {
		sta = rcu_dereference_protected(mvm->fw_id_to_mac_id[i],
						lockdep_is_held(&mvm->mutex));
		if (!sta || IS_ERR(sta) || !sta->tdls)
			continue;

		mvmsta = iwl_mvm_sta_from_mac80211(sta);
		ieee80211_tdls_oper_request(mvmsta->vif, sta->addr,
				NL80211_TDLS_TEARDOWN,
				WLAN_REASON_TDLS_TEARDOWN_UNSPECIFIED,
				GFP_KERNEL);
	}
}

int iwl_mvm_tdls_sta_count(struct iwl_mvm *mvm, struct ieee80211_vif *vif)
{
	struct ieee80211_sta *sta;
	struct iwl_mvm_sta *mvmsta;
	int count = 0;
	int i;

	lockdep_assert_held(&mvm->mutex);

	for (i = 0; i < IWL_MVM_STATION_COUNT; i++) {
		sta = rcu_dereference_protected(mvm->fw_id_to_mac_id[i],
						lockdep_is_held(&mvm->mutex));
		if (!sta || IS_ERR(sta) || !sta->tdls)
			continue;

		if (vif) {
			mvmsta = iwl_mvm_sta_from_mac80211(sta);
			if (mvmsta->vif != vif)
				continue;
		}

		count++;
	}

	return count;
}

static void iwl_mvm_tdls_config(struct iwl_mvm *mvm, struct ieee80211_vif *vif)
{
	struct iwl_rx_packet *pkt;
	struct iwl_tdls_config_res *resp;
	struct iwl_tdls_config_cmd tdls_cfg_cmd = {};
	struct iwl_host_cmd cmd = {
		.id = TDLS_CONFIG_CMD,
		.flags = CMD_WANT_SKB,
		.data = { &tdls_cfg_cmd, },
		.len = { sizeof(struct iwl_tdls_config_cmd), },
	};
	struct ieee80211_sta *sta;
	int ret, i, cnt;
	struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);

	lockdep_assert_held(&mvm->mutex);

	tdls_cfg_cmd.id_and_color =
		cpu_to_le32(FW_CMD_ID_AND_COLOR(mvmvif->id, mvmvif->color));
	tdls_cfg_cmd.tx_to_ap_tid = IWL_MVM_TDLS_FW_TID;
	tdls_cfg_cmd.tx_to_ap_ssn = cpu_to_le16(0); /* not used for now */

	/* for now the Tx cmd is empty and unused */

	/* populate TDLS peer data */
	cnt = 0;
	for (i = 0; i < IWL_MVM_STATION_COUNT; i++) {
		sta = rcu_dereference_protected(mvm->fw_id_to_mac_id[i],
						lockdep_is_held(&mvm->mutex));
		if (IS_ERR_OR_NULL(sta) || !sta->tdls)
			continue;

		tdls_cfg_cmd.sta_info[cnt].sta_id = i;
		tdls_cfg_cmd.sta_info[cnt].tx_to_peer_tid =
							IWL_MVM_TDLS_FW_TID;
		tdls_cfg_cmd.sta_info[cnt].tx_to_peer_ssn = cpu_to_le16(0);
		tdls_cfg_cmd.sta_info[cnt].is_initiator =
				cpu_to_le32(sta->tdls_initiator ? 1 : 0);

		cnt++;
	}

	tdls_cfg_cmd.tdls_peer_count = cnt;
	IWL_DEBUG_TDLS(mvm, "send TDLS config to FW for %d peers\n", cnt);

	ret = iwl_mvm_send_cmd(mvm, &cmd);
	if (WARN_ON_ONCE(ret))
		return;

	pkt = cmd.resp_pkt;
	if (pkt->hdr.flags & IWL_CMD_FAILED_MSK) {
		IWL_ERR(mvm, "Bad return from TDLS_CONFIG_COMMAND (0x%08X)\n",
			pkt->hdr.flags);
		goto exit;
	}

	if (WARN_ON_ONCE(iwl_rx_packet_payload_len(pkt) != sizeof(*resp)))
		goto exit;

	/* we don't really care about the response at this point */

exit:
	iwl_free_resp(&cmd);
}

void iwl_mvm_recalc_tdls_state(struct iwl_mvm *mvm, struct ieee80211_vif *vif,
			       bool sta_added)
{
	int tdls_sta_cnt = iwl_mvm_tdls_sta_count(mvm, vif);

	/* when the first peer joins, send a power update first */
	if (tdls_sta_cnt == 1 && sta_added)
		iwl_mvm_power_update_mac(mvm);

	/* configure the FW with TDLS peer info */
	iwl_mvm_tdls_config(mvm, vif);

	/* when the last peer leaves, send a power update last */
	if (tdls_sta_cnt == 0 && !sta_added)
		iwl_mvm_power_update_mac(mvm);
}

void iwl_mvm_mac_mgd_protect_tdls_discover(struct ieee80211_hw *hw,
					   struct ieee80211_vif *vif)
{
	struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
	u32 duration = 2 * vif->bss_conf.dtim_period * vif->bss_conf.beacon_int;

	/*
	 * iwl_mvm_protect_session() reads directly from the device
	 * (the system time), so make sure it is available.
	 */
	if (iwl_mvm_ref_sync(mvm, IWL_MVM_REF_PROTECT_TDLS))
		return;

	mutex_lock(&mvm->mutex);
	/* Protect the session to hear the TDLS setup response on the channel */
	iwl_mvm_protect_session(mvm, vif, duration, duration, 100, true);
	mutex_unlock(&mvm->mutex);

	iwl_mvm_unref(mvm, IWL_MVM_REF_PROTECT_TDLS);
}

static const char *
iwl_mvm_tdls_cs_state_str(enum iwl_mvm_tdls_cs_state state)
{
	switch (state) {
	case IWL_MVM_TDLS_SW_IDLE:
		return "IDLE";
	case IWL_MVM_TDLS_SW_REQ_SENT:
		return "REQ SENT";
	case IWL_MVM_TDLS_SW_REQ_RCVD:
		return "REQ RECEIVED";
	case IWL_MVM_TDLS_SW_ACTIVE:
		return "ACTIVE";
	}

	return NULL;
}

static void iwl_mvm_tdls_update_cs_state(struct iwl_mvm *mvm,
					 enum iwl_mvm_tdls_cs_state state)
{
	if (mvm->tdls_cs.state == state)
		return;

	IWL_DEBUG_TDLS(mvm, "TDLS channel switch state: %s -> %s\n",
		       iwl_mvm_tdls_cs_state_str(mvm->tdls_cs.state),
		       iwl_mvm_tdls_cs_state_str(state));
	mvm->tdls_cs.state = state;

	if (state == IWL_MVM_TDLS_SW_IDLE)
		mvm->tdls_cs.cur_sta_id = IWL_MVM_STATION_COUNT;
}

int iwl_mvm_rx_tdls_notif(struct iwl_mvm *mvm, struct iwl_rx_cmd_buffer *rxb,
			  struct iwl_device_cmd *cmd)
{
	struct iwl_rx_packet *pkt = rxb_addr(rxb);
	struct iwl_tdls_channel_switch_notif *notif = (void *)pkt->data;
	struct ieee80211_sta *sta;
	unsigned int delay;
	struct iwl_mvm_sta *mvmsta;
	struct ieee80211_vif *vif;
	u32 sta_id = le32_to_cpu(notif->sta_id);

	lockdep_assert_held(&mvm->mutex);

	/* can fail sometimes */
	if (!le32_to_cpu(notif->status)) {
		iwl_mvm_tdls_update_cs_state(mvm, IWL_MVM_TDLS_SW_IDLE);
		goto out;
	}

	if (WARN_ON(sta_id >= IWL_MVM_STATION_COUNT))
		goto out;

	sta = rcu_dereference_protected(mvm->fw_id_to_mac_id[sta_id],
					lockdep_is_held(&mvm->mutex));
	/* the station may not be here, but if it is, it must be a TDLS peer */
	if (IS_ERR_OR_NULL(sta) || WARN_ON(!sta->tdls))
		goto out;

	mvmsta = iwl_mvm_sta_from_mac80211(sta);
	vif = mvmsta->vif;

	/*
	 * Update state and possibly switch again after this is over (DTIM).
	 * Also convert TU to msec.
	 */
	delay = TU_TO_MS(vif->bss_conf.dtim_period * vif->bss_conf.beacon_int);
	mod_delayed_work(system_wq, &mvm->tdls_cs.dwork,
			 msecs_to_jiffies(delay));

	iwl_mvm_tdls_update_cs_state(mvm, IWL_MVM_TDLS_SW_ACTIVE);

out:
	return 0;
}

static int
iwl_mvm_tdls_check_action(struct iwl_mvm *mvm,
			  enum iwl_tdls_channel_switch_type type,
			  const u8 *peer, bool peer_initiator)
{
	bool same_peer = false;
	int ret = 0;

	/* get the existing peer if it's there */
	if (mvm->tdls_cs.state != IWL_MVM_TDLS_SW_IDLE &&
	    mvm->tdls_cs.cur_sta_id != IWL_MVM_STATION_COUNT) {
		struct ieee80211_sta *sta = rcu_dereference_protected(
				mvm->fw_id_to_mac_id[mvm->tdls_cs.cur_sta_id],
				lockdep_is_held(&mvm->mutex));
		if (!IS_ERR_OR_NULL(sta))
			same_peer = ether_addr_equal(peer, sta->addr);
	}

	switch (mvm->tdls_cs.state) {
	case IWL_MVM_TDLS_SW_IDLE:
		/*
		 * might be spurious packet from the peer after the switch is
		 * already done
		 */
		if (type == TDLS_MOVE_CH)
			ret = -EINVAL;
		break;
	case IWL_MVM_TDLS_SW_REQ_SENT:
		/*
		 * We received a ch-switch request while an outgoing one is
		 * pending. Allow it to proceed if the other peer is the same
		 * one we sent to, and we are not the link initiator.
		 */
		if (type == TDLS_SEND_CHAN_SW_RESP_AND_MOVE_CH) {
			if (!same_peer)
				ret = -EBUSY;
			else if (!peer_initiator) /* we are the initiator */
				ret = -EBUSY;
		}
		break;
	case IWL_MVM_TDLS_SW_REQ_RCVD:
		/* as above, allow the link initiator to proceed */
		if (type == TDLS_SEND_CHAN_SW_REQ) {
			if (!same_peer)
				ret = -EBUSY;
			else if (peer_initiator) /* they are the initiator */
				ret = -EBUSY;
		} else if (type == TDLS_MOVE_CH) {
			ret = -EINVAL;
		}
		break;
	case IWL_MVM_TDLS_SW_ACTIVE:
		/* we don't allow initiations during active channel switch */
		if (type == TDLS_SEND_CHAN_SW_REQ)
			ret = -EINVAL;
		break;
	}

	if (ret)
		IWL_DEBUG_TDLS(mvm,
			       "Invalid TDLS action %d state %d peer %pM same_peer %d initiator %d\n",
			       type, mvm->tdls_cs.state, peer, same_peer,
			       peer_initiator);

	return ret;
}

static int
iwl_mvm_tdls_config_channel_switch(struct iwl_mvm *mvm,
				   struct ieee80211_vif *vif,
				   enum iwl_tdls_channel_switch_type type,
				   const u8 *peer, bool peer_initiator,
				   u8 oper_class,
				   struct cfg80211_chan_def *chandef,
				   u32 timestamp, u16 switch_time,
				   u16 switch_timeout, struct sk_buff *skb,
				   u32 ch_sw_tm_ie)
{
	struct ieee80211_sta *sta;
	struct iwl_mvm_sta *mvmsta;
	struct ieee80211_tx_info *info;
	struct ieee80211_hdr *hdr;
	struct iwl_tdls_channel_switch_cmd cmd = {0};
	int ret;

	lockdep_assert_held(&mvm->mutex);

	ret = iwl_mvm_tdls_check_action(mvm, type, peer, peer_initiator);
	if (ret)
		return ret;

	if (!skb || WARN_ON(skb->len > IWL_TDLS_CH_SW_FRAME_MAX_SIZE)) {
		ret = -EINVAL;
		goto out;
	}

	cmd.switch_type = type;
	cmd.timing.frame_timestamp = cpu_to_le32(timestamp);
	cmd.timing.switch_time = cpu_to_le32(switch_time);
	cmd.timing.switch_timeout = cpu_to_le32(switch_timeout);

	rcu_read_lock();
	sta = ieee80211_find_sta(vif, peer);
	if (!sta) {
		rcu_read_unlock();
		ret = -ENOENT;
		goto out;
	}
	mvmsta = iwl_mvm_sta_from_mac80211(sta);
	cmd.peer_sta_id = cpu_to_le32(mvmsta->sta_id);

	if (!chandef) {
		if (mvm->tdls_cs.state == IWL_MVM_TDLS_SW_REQ_SENT &&
		    mvm->tdls_cs.peer.chandef.chan) {
			/* actually moving to the channel */
			chandef = &mvm->tdls_cs.peer.chandef;
		} else if (mvm->tdls_cs.state == IWL_MVM_TDLS_SW_ACTIVE &&
			   type == TDLS_MOVE_CH) {
			/* we need to return to base channel */
			struct ieee80211_chanctx_conf *chanctx =
					rcu_dereference(vif->chanctx_conf);

			if (WARN_ON_ONCE(!chanctx)) {
				rcu_read_unlock();
				goto out;
			}

			chandef = &chanctx->def;
		}
	}

	if (chandef) {
		cmd.ci.band = (chandef->chan->band == IEEE80211_BAND_2GHZ ?
			       PHY_BAND_24 : PHY_BAND_5);
		cmd.ci.channel = chandef->chan->hw_value;
		cmd.ci.width = iwl_mvm_get_channel_width(chandef);
		cmd.ci.ctrl_pos = iwl_mvm_get_ctrl_pos(chandef);
	}

	/* keep quota calculation simple for now - 50% of DTIM for TDLS */
	cmd.timing.max_offchan_duration =
			cpu_to_le32(TU_TO_US(vif->bss_conf.dtim_period *
					     vif->bss_conf.beacon_int) / 2);

	/* Switch time is the first element in the switch-timing IE. */
	cmd.frame.switch_time_offset = cpu_to_le32(ch_sw_tm_ie + 2);

	info = IEEE80211_SKB_CB(skb);
	if (info->control.hw_key)
		iwl_mvm_set_tx_cmd_crypto(mvm, info, &cmd.frame.tx_cmd, skb);

	iwl_mvm_set_tx_cmd(mvm, skb, &cmd.frame.tx_cmd, info,
			   mvmsta->sta_id);

	hdr = (void *)skb->data;
	iwl_mvm_set_tx_cmd_rate(mvm, &cmd.frame.tx_cmd, info, sta,
				hdr->frame_control);
	rcu_read_unlock();

	memcpy(cmd.frame.data, skb->data, skb->len);

	ret = iwl_mvm_send_cmd_pdu(mvm, TDLS_CHANNEL_SWITCH_CMD, 0,
				   sizeof(cmd), &cmd);
	if (ret) {
		IWL_ERR(mvm, "Failed to send TDLS_CHANNEL_SWITCH cmd: %d\n",
			ret);
		goto out;
	}

	/* channel switch has started, update state */
	if (type != TDLS_MOVE_CH) {
		mvm->tdls_cs.cur_sta_id = mvmsta->sta_id;
		iwl_mvm_tdls_update_cs_state(mvm,
					     type == TDLS_SEND_CHAN_SW_REQ ?
					     IWL_MVM_TDLS_SW_REQ_SENT :
					     IWL_MVM_TDLS_SW_REQ_RCVD);
	}

out:

	/* channel switch failed - we are idle */
	if (ret)
		iwl_mvm_tdls_update_cs_state(mvm, IWL_MVM_TDLS_SW_IDLE);

	return ret;
}

void iwl_mvm_tdls_ch_switch_work(struct work_struct *work)
{
	struct iwl_mvm *mvm;
	struct ieee80211_sta *sta;
	struct iwl_mvm_sta *mvmsta;
	struct ieee80211_vif *vif;
	unsigned int delay;
	int ret;

	mvm = container_of(work, struct iwl_mvm, tdls_cs.dwork.work);
	mutex_lock(&mvm->mutex);

	/* called after an active channel switch has finished or timed-out */
	iwl_mvm_tdls_update_cs_state(mvm, IWL_MVM_TDLS_SW_IDLE);

	/* station might be gone, in that case do nothing */
	if (mvm->tdls_cs.peer.sta_id == IWL_MVM_STATION_COUNT)
		goto out;

	sta = rcu_dereference_protected(
				mvm->fw_id_to_mac_id[mvm->tdls_cs.peer.sta_id],
				lockdep_is_held(&mvm->mutex));
	/* the station may not be here, but if it is, it must be a TDLS peer */
	if (!sta || IS_ERR(sta) || WARN_ON(!sta->tdls))
		goto out;

	mvmsta = iwl_mvm_sta_from_mac80211(sta);
	vif = mvmsta->vif;
	ret = iwl_mvm_tdls_config_channel_switch(mvm, vif,
						 TDLS_SEND_CHAN_SW_REQ,
						 sta->addr,
						 mvm->tdls_cs.peer.initiator,
						 mvm->tdls_cs.peer.op_class,
						 &mvm->tdls_cs.peer.chandef,
						 0, 0, 0,
						 mvm->tdls_cs.peer.skb,
						 mvm->tdls_cs.peer.ch_sw_tm_ie);
	if (ret)
		IWL_ERR(mvm, "Not sending TDLS channel switch: %d\n", ret);

	/* retry after a DTIM if we failed sending now */
	delay = TU_TO_MS(vif->bss_conf.dtim_period * vif->bss_conf.beacon_int);
	queue_delayed_work(system_wq, &mvm->tdls_cs.dwork,
			   msecs_to_jiffies(delay));
out:
	mutex_unlock(&mvm->mutex);
}

int
iwl_mvm_tdls_channel_switch(struct ieee80211_hw *hw,
			    struct ieee80211_vif *vif,
			    struct ieee80211_sta *sta, u8 oper_class,
			    struct cfg80211_chan_def *chandef,
			    struct sk_buff *tmpl_skb, u32 ch_sw_tm_ie)
{
	struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
	struct iwl_mvm_sta *mvmsta;
	unsigned int delay;
	int ret;

	mutex_lock(&mvm->mutex);

	IWL_DEBUG_TDLS(mvm, "TDLS channel switch with %pM ch %d width %d\n",
		       sta->addr, chandef->chan->center_freq, chandef->width);

	/* we only support a single peer for channel switching */
	if (mvm->tdls_cs.peer.sta_id != IWL_MVM_STATION_COUNT) {
		IWL_DEBUG_TDLS(mvm,
			       "Existing peer. Can't start switch with %pM\n",
			       sta->addr);
		ret = -EBUSY;
		goto out;
	}

	ret = iwl_mvm_tdls_config_channel_switch(mvm, vif,
						 TDLS_SEND_CHAN_SW_REQ,
						 sta->addr, sta->tdls_initiator,
						 oper_class, chandef, 0, 0, 0,
						 tmpl_skb, ch_sw_tm_ie);
	if (ret)
		goto out;

	/*
	 * Mark the peer as "in tdls switch" for this vif. We only allow a
	 * single such peer per vif.
	 */
	mvm->tdls_cs.peer.skb = skb_copy(tmpl_skb, GFP_KERNEL);
	if (!mvm->tdls_cs.peer.skb) {
		ret = -ENOMEM;
		goto out;
	}

	mvmsta = iwl_mvm_sta_from_mac80211(sta);
	mvm->tdls_cs.peer.sta_id = mvmsta->sta_id;
	mvm->tdls_cs.peer.chandef = *chandef;
	mvm->tdls_cs.peer.initiator = sta->tdls_initiator;
	mvm->tdls_cs.peer.op_class = oper_class;
	mvm->tdls_cs.peer.ch_sw_tm_ie = ch_sw_tm_ie;

	/*
	 * Wait for 2 DTIM periods before attempting the next switch. The next
	 * switch will be made sooner if the current one completes before that.
	 */
	delay = 2 * TU_TO_MS(vif->bss_conf.dtim_period *
			     vif->bss_conf.beacon_int);
	mod_delayed_work(system_wq, &mvm->tdls_cs.dwork,
			 msecs_to_jiffies(delay));

out:
	mutex_unlock(&mvm->mutex);
	return ret;
}

void iwl_mvm_tdls_cancel_channel_switch(struct ieee80211_hw *hw,
					struct ieee80211_vif *vif,
					struct ieee80211_sta *sta)
{
	struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
	struct ieee80211_sta *cur_sta;
	bool wait_for_phy = false;

	mutex_lock(&mvm->mutex);

	IWL_DEBUG_TDLS(mvm, "TDLS cancel channel switch with %pM\n", sta->addr);

	/* we only support a single peer for channel switching */
	if (mvm->tdls_cs.peer.sta_id == IWL_MVM_STATION_COUNT) {
		IWL_DEBUG_TDLS(mvm, "No ch switch peer - %pM\n", sta->addr);
		goto out;
	}

	cur_sta = rcu_dereference_protected(
				mvm->fw_id_to_mac_id[mvm->tdls_cs.peer.sta_id],
				lockdep_is_held(&mvm->mutex));
	/* make sure it's the same peer */
	if (cur_sta != sta)
		goto out;

	/*
	 * If we're currently in a switch because of the now canceled peer,
	 * wait a DTIM here to make sure the phy is back on the base channel.
	 * We can't otherwise force it.
	 */
	if (mvm->tdls_cs.cur_sta_id == mvm->tdls_cs.peer.sta_id &&
	    mvm->tdls_cs.state != IWL_MVM_TDLS_SW_IDLE)
		wait_for_phy = true;

	mvm->tdls_cs.peer.sta_id = IWL_MVM_STATION_COUNT;
	dev_kfree_skb(mvm->tdls_cs.peer.skb);
	mvm->tdls_cs.peer.skb = NULL;

out:
	mutex_unlock(&mvm->mutex);

	/* make sure the phy is on the base channel */
	if (wait_for_phy)
		msleep(TU_TO_MS(vif->bss_conf.dtim_period *
				vif->bss_conf.beacon_int));

	/* flush the channel switch state */
	flush_delayed_work(&mvm->tdls_cs.dwork);

	IWL_DEBUG_TDLS(mvm, "TDLS ending channel switch with %pM\n", sta->addr);
}

void
iwl_mvm_tdls_recv_channel_switch(struct ieee80211_hw *hw,
				 struct ieee80211_vif *vif,
				 struct ieee80211_tdls_ch_sw_params *params)
{
	struct iwl_mvm *mvm = IWL_MAC80211_GET_MVM(hw);
	enum iwl_tdls_channel_switch_type type;
	unsigned int delay;

	mutex_lock(&mvm->mutex);

	IWL_DEBUG_TDLS(mvm,
		       "Received TDLS ch switch action %d from %pM status %d\n",
		       params->action_code, params->sta->addr, params->status);

	/*
	 * we got a non-zero status from a peer we were switching to - move to
	 * the idle state and retry again later
	 */
	if (params->action_code == WLAN_TDLS_CHANNEL_SWITCH_RESPONSE &&
	    params->status != 0 &&
	    mvm->tdls_cs.state == IWL_MVM_TDLS_SW_REQ_SENT &&
	    mvm->tdls_cs.cur_sta_id != IWL_MVM_STATION_COUNT) {
		struct ieee80211_sta *cur_sta;

		/* make sure it's the same peer */
		cur_sta = rcu_dereference_protected(
				mvm->fw_id_to_mac_id[mvm->tdls_cs.cur_sta_id],
				lockdep_is_held(&mvm->mutex));
		if (cur_sta == params->sta) {
			iwl_mvm_tdls_update_cs_state(mvm,
						     IWL_MVM_TDLS_SW_IDLE);
			goto retry;
		}
	}

	type = (params->action_code == WLAN_TDLS_CHANNEL_SWITCH_REQUEST) ?
	       TDLS_SEND_CHAN_SW_RESP_AND_MOVE_CH : TDLS_MOVE_CH;

	iwl_mvm_tdls_config_channel_switch(mvm, vif, type, params->sta->addr,
					   params->sta->tdls_initiator, 0,
					   params->chandef, params->timestamp,
					   params->switch_time,
					   params->switch_timeout,
					   params->tmpl_skb,
					   params->ch_sw_tm_ie);

retry:
	/* register a timeout in case we don't succeed in switching */
	delay = vif->bss_conf.dtim_period * vif->bss_conf.beacon_int *
		1024 / 1000;
	mod_delayed_work(system_wq, &mvm->tdls_cs.dwork,
			 msecs_to_jiffies(delay));
	mutex_unlock(&mvm->mutex);
}