/*
   * Off-channel operation helpers
   *
   * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
   * Copyright 2004, Instant802 Networks, Inc.
   * Copyright 2005, Devicescape Software, Inc.
   * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
   * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
   * Copyright 2009	Johannes Berg <johannes@sipsolutions.net>
   *
   * 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/export.h>

  #include <net/mac80211.h>
  #include "ieee80211_i.h"

  #include "driver-trace.h"

  
  /*

   * Tell our hardware to disable PS.
   * Optionally inform AP that we will go to sleep so that it will buffer
   * the frames while we are doing off-channel work.  This is optional
   * because we *may* be doing work on-operating channel, and want our
   * hardware unconditionally awake, but still let the AP send us normal frames.

   */

  static void ieee80211_offchannel_ps_enable(struct ieee80211_sub_if_data *sdata,
  					   bool tell_ap)

  {
  	struct ieee80211_local *local = sdata->local;

  	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;

  
  	local->offchannel_ps_enabled = false;
  
  	/* FIXME: what to do when local->pspolling is true? */
  
  	del_timer_sync(&local->dynamic_ps_timer);

  	del_timer_sync(&ifmgd->bcn_mon_timer);

  	del_timer_sync(&ifmgd->conn_mon_timer);

  	cancel_work_sync(&local->dynamic_ps_enable_work);
  
  	if (local->hw.conf.flags & IEEE80211_CONF_PS) {
  		local->offchannel_ps_enabled = true;
  		local->hw.conf.flags &= ~IEEE80211_CONF_PS;
  		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
  	}

  	if (tell_ap && (!local->offchannel_ps_enabled ||
  			!(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK)))

  		/*
  		 * If power save was enabled, no need to send a nullfunc
  		 * frame because AP knows that we are sleeping. But if the
  		 * hardware is creating the nullfunc frame for power save
  		 * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not
  		 * enabled) and power save was enabled, the firmware just
  		 * sent a null frame with power save disabled. So we need
  		 * to send a new nullfunc frame to inform the AP that we
  		 * are again sleeping.
  		 */
  		ieee80211_send_nullfunc(local, sdata, 1);
  }
  
  /* inform AP that we are awake again, unless power save is enabled */
  static void ieee80211_offchannel_ps_disable(struct ieee80211_sub_if_data *sdata)
  {
  	struct ieee80211_local *local = sdata->local;
  
  	if (!local->ps_sdata)
  		ieee80211_send_nullfunc(local, sdata, 0);
  	else if (local->offchannel_ps_enabled) {
  		/*
  		 * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware
  		 * will send a nullfunc frame with the powersave bit set
  		 * even though the AP already knows that we are sleeping.
  		 * This could be avoided by sending a null frame with power
  		 * save bit disabled before enabling the power save, but
  		 * this doesn't gain anything.
  		 *
  		 * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need
  		 * to send a nullfunc frame because AP already knows that
  		 * we are sleeping, let's just enable power save mode in
  		 * hardware.
  		 */

  		/* TODO:  Only set hardware if CONF_PS changed?
  		 * TODO:  Should we set offchannel_ps_enabled to false?
  		 */

  		local->hw.conf.flags |= IEEE80211_CONF_PS;
  		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS);
  	} else if (local->hw.conf.dynamic_ps_timeout > 0) {
  		/*
  		 * If IEEE80211_CONF_PS was not set and the dynamic_ps_timer
  		 * had been running before leaving the operating channel,
  		 * restart the timer now and send a nullfunc frame to inform
  		 * the AP that we are awake.
  		 */
  		ieee80211_send_nullfunc(local, sdata, 0);
  		mod_timer(&local->dynamic_ps_timer, jiffies +
  			  msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout));
  	}

  	ieee80211_sta_reset_beacon_monitor(sdata);

  	ieee80211_sta_reset_conn_monitor(sdata);

  }

  void ieee80211_offchannel_stop_vifs(struct ieee80211_local *local,
  				    bool offchannel_ps_enable)

  {
  	struct ieee80211_sub_if_data *sdata;

  	/*
  	 * notify the AP about us leaving the channel and stop all
  	 * STA interfaces.
  	 */

  	mutex_lock(&local->iflist_mtx);
  	list_for_each_entry(sdata, &local->interfaces, list) {
  		if (!ieee80211_sdata_running(sdata))
  			continue;

  		if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
  			set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
  
  		/* Check to see if we should disable beaconing. */

  		if (sdata->vif.type == NL80211_IFTYPE_AP ||
  		    sdata->vif.type == NL80211_IFTYPE_ADHOC ||
  		    sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
  			ieee80211_bss_info_change_notify(
  				sdata, BSS_CHANGED_BEACON_ENABLED);

  		if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {

  			netif_tx_stop_all_queues(sdata->dev);

  			if (offchannel_ps_enable &&
  			    (sdata->vif.type == NL80211_IFTYPE_STATION) &&
  			    sdata->u.mgd.associated)
  				ieee80211_offchannel_ps_enable(sdata, true);

  		}

  	}
  	mutex_unlock(&local->iflist_mtx);
  }

  void ieee80211_offchannel_return(struct ieee80211_local *local,

  				 bool offchannel_ps_disable)

  {
  	struct ieee80211_sub_if_data *sdata;
  
  	mutex_lock(&local->iflist_mtx);
  	list_for_each_entry(sdata, &local->interfaces, list) {

  		if (sdata->vif.type != NL80211_IFTYPE_MONITOR)
  			clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);

  		if (!ieee80211_sdata_running(sdata))
  			continue;
  
  		/* Tell AP we're back */

  		if (offchannel_ps_disable &&
  		    sdata->vif.type == NL80211_IFTYPE_STATION) {

  			if (sdata->u.mgd.associated)
  				ieee80211_offchannel_ps_disable(sdata);

  		}

  		if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {

  			/*
  			 * This may wake up queues even though the driver
  			 * currently has them stopped. This is not very
  			 * likely, since the driver won't have gotten any
  			 * (or hardly any) new packets while we weren't
  			 * on the right channel, and even if it happens
  			 * it will at most lead to queueing up one more
  			 * packet per queue in mac80211 rather than on
  			 * the interface qdisc.
  			 */

  			netif_tx_wake_all_queues(sdata->dev);

  		}

  		if (sdata->vif.type == NL80211_IFTYPE_AP ||
  		    sdata->vif.type == NL80211_IFTYPE_ADHOC ||
  		    sdata->vif.type == NL80211_IFTYPE_MESH_POINT)

  			ieee80211_bss_info_change_notify(
  				sdata, BSS_CHANGED_BEACON_ENABLED);
  	}
  	mutex_unlock(&local->iflist_mtx);
  }

  
  static void ieee80211_hw_roc_start(struct work_struct *work)
  {
  	struct ieee80211_local *local =
  		container_of(work, struct ieee80211_local, hw_roc_start);

  	struct ieee80211_sub_if_data *sdata;

  
  	mutex_lock(&local->mtx);
  
  	if (!local->hw_roc_channel) {
  		mutex_unlock(&local->mtx);
  		return;
  	}

  	if (local->hw_roc_skb) {
  		sdata = IEEE80211_DEV_TO_SUB_IF(local->hw_roc_dev);
  		ieee80211_tx_skb(sdata, local->hw_roc_skb);
  		local->hw_roc_skb = NULL;
  	} else {
  		cfg80211_ready_on_channel(local->hw_roc_dev,
  					  local->hw_roc_cookie,
  					  local->hw_roc_channel,
  					  local->hw_roc_channel_type,
  					  local->hw_roc_duration,
  					  GFP_KERNEL);
  	}

  	ieee80211_recalc_idle(local);

  	mutex_unlock(&local->mtx);
  }
  
  void ieee80211_ready_on_channel(struct ieee80211_hw *hw)
  {
  	struct ieee80211_local *local = hw_to_local(hw);
  
  	trace_api_ready_on_channel(local);
  
  	ieee80211_queue_work(hw, &local->hw_roc_start);
  }
  EXPORT_SYMBOL_GPL(ieee80211_ready_on_channel);
  
  static void ieee80211_hw_roc_done(struct work_struct *work)
  {
  	struct ieee80211_local *local =
  		container_of(work, struct ieee80211_local, hw_roc_done);
  
  	mutex_lock(&local->mtx);
  
  	if (!local->hw_roc_channel) {
  		mutex_unlock(&local->mtx);
  		return;
  	}

  	if (!local->hw_roc_for_tx)
  		cfg80211_remain_on_channel_expired(local->hw_roc_dev,
  						   local->hw_roc_cookie,
  						   local->hw_roc_channel,
  						   local->hw_roc_channel_type,
  						   GFP_KERNEL);

  
  	local->hw_roc_channel = NULL;
  	local->hw_roc_cookie = 0;
  
  	ieee80211_recalc_idle(local);
  
  	mutex_unlock(&local->mtx);
  }
  
  void ieee80211_remain_on_channel_expired(struct ieee80211_hw *hw)
  {
  	struct ieee80211_local *local = hw_to_local(hw);
  
  	trace_api_remain_on_channel_expired(local);
  
  	ieee80211_queue_work(hw, &local->hw_roc_done);
  }
  EXPORT_SYMBOL_GPL(ieee80211_remain_on_channel_expired);
  
  void ieee80211_hw_roc_setup(struct ieee80211_local *local)
  {
  	INIT_WORK(&local->hw_roc_start, ieee80211_hw_roc_start);
  	INIT_WORK(&local->hw_roc_done, ieee80211_hw_roc_done);
  }