/*
   * Mac80211 power management API for ST-Ericsson CW1200 drivers
   *
   * Copyright (c) 2011, 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/module.h>
  #include <linux/if_ether.h>
  #include "cw1200.h"
  #include "pm.h"
  #include "sta.h"
  #include "bh.h"
  #include "hwbus.h"
  
  #define CW1200_BEACON_SKIPPING_MULTIPLIER 3
  
  struct cw1200_udp_port_filter {
  	struct wsm_udp_port_filter_hdr hdr;
  	/* Up to 4 filters are allowed. */
  	struct wsm_udp_port_filter filters[WSM_MAX_FILTER_ELEMENTS];
  } __packed;
  
  struct cw1200_ether_type_filter {
  	struct wsm_ether_type_filter_hdr hdr;
  	/* Up to 4 filters are allowed. */
  	struct wsm_ether_type_filter filters[WSM_MAX_FILTER_ELEMENTS];
  } __packed;
  
  static struct cw1200_udp_port_filter cw1200_udp_port_filter_on = {
  	.hdr.num = 2,
  	.filters = {
  		[0] = {
  			.action = WSM_FILTER_ACTION_FILTER_OUT,
  			.type = WSM_FILTER_PORT_TYPE_DST,
  			.port = __cpu_to_le16(67), /* DHCP Bootps */
  		},
  		[1] = {
  			.action = WSM_FILTER_ACTION_FILTER_OUT,
  			.type = WSM_FILTER_PORT_TYPE_DST,
  			.port = __cpu_to_le16(68), /* DHCP Bootpc */
  		},
  	}
  };
  
  static struct wsm_udp_port_filter_hdr cw1200_udp_port_filter_off = {
  	.num = 0,
  };
  
  #ifndef ETH_P_WAPI
  #define ETH_P_WAPI     0x88B4
  #endif
  
  static struct cw1200_ether_type_filter cw1200_ether_type_filter_on = {
  	.hdr.num = 4,
  	.filters = {
  		[0] = {
  			.action = WSM_FILTER_ACTION_FILTER_IN,
  			.type = __cpu_to_le16(ETH_P_IP),
  		},
  		[1] = {
  			.action = WSM_FILTER_ACTION_FILTER_IN,
  			.type = __cpu_to_le16(ETH_P_PAE),
  		},
  		[2] = {
  			.action = WSM_FILTER_ACTION_FILTER_IN,
  			.type = __cpu_to_le16(ETH_P_WAPI),
  		},
  		[3] = {
  			.action = WSM_FILTER_ACTION_FILTER_IN,
  			.type = __cpu_to_le16(ETH_P_ARP),
  		},
  	},
  };
  
  static struct wsm_ether_type_filter_hdr cw1200_ether_type_filter_off = {
  	.num = 0,
  };
  
  /* private */
  struct cw1200_suspend_state {
  	unsigned long bss_loss_tmo;
  	unsigned long join_tmo;
  	unsigned long direct_probe;
  	unsigned long link_id_gc;
  	bool beacon_skipping;
  	u8 prev_ps_mode;
  };
  
  static void cw1200_pm_stay_awake_tmo(unsigned long arg)
  {
  	/* XXX what's the point of this ? */
  }
  
  int cw1200_pm_init(struct cw1200_pm_state *pm,
  		   struct cw1200_common *priv)
  {
  	spin_lock_init(&pm->lock);
  
  	setup_timer(&pm->stay_awake, cw1200_pm_stay_awake_tmo,
  		    (unsigned long)pm);
  
  	return 0;
  }
  
  void cw1200_pm_deinit(struct cw1200_pm_state *pm)
  {
  	del_timer_sync(&pm->stay_awake);
  }
  
  void cw1200_pm_stay_awake(struct cw1200_pm_state *pm,
  			  unsigned long tmo)
  {
  	long cur_tmo;
  	spin_lock_bh(&pm->lock);
  	cur_tmo = pm->stay_awake.expires - jiffies;
  	if (!timer_pending(&pm->stay_awake) || cur_tmo < (long)tmo)
  		mod_timer(&pm->stay_awake, jiffies + tmo);
  	spin_unlock_bh(&pm->lock);
  }
  
  static long cw1200_suspend_work(struct delayed_work *work)
  {
  	int ret = cancel_delayed_work(work);
  	long tmo;
  	if (ret > 0) {
  		/* Timer is pending */
  		tmo = work->timer.expires - jiffies;
  		if (tmo < 0)
  			tmo = 0;
  	} else {
  		tmo = -1;
  	}
  	return tmo;
  }
  
  static int cw1200_resume_work(struct cw1200_common *priv,
  			       struct delayed_work *work,
  			       unsigned long tmo)
  {
  	if ((long)tmo < 0)
  		return 1;
  
  	return queue_delayed_work(priv->workqueue, work, tmo);
  }
  
  int cw1200_can_suspend(struct cw1200_common *priv)
  {
  	if (atomic_read(&priv->bh_rx)) {
  		wiphy_dbg(priv->hw->wiphy, "Suspend interrupted.
  ");
  		return 0;
  	}
  	return 1;
  }
  EXPORT_SYMBOL_GPL(cw1200_can_suspend);
  
  int cw1200_wow_suspend(struct ieee80211_hw *hw, struct cfg80211_wowlan *wowlan)
  {
  	struct cw1200_common *priv = hw->priv;
  	struct cw1200_pm_state *pm_state = &priv->pm_state;
  	struct cw1200_suspend_state *state;
  	int ret;
  
  	spin_lock_bh(&pm_state->lock);
  	ret = timer_pending(&pm_state->stay_awake);
  	spin_unlock_bh(&pm_state->lock);
  	if (ret)
  		return -EAGAIN;
  
  	/* Do not suspend when datapath is not idle */
  	if (priv->tx_queue_stats.num_queued)
  		return -EBUSY;
  
  	/* Make sure there is no configuration requests in progress. */
  	if (!mutex_trylock(&priv->conf_mutex))
  		return -EBUSY;
  
  	/* Ensure pending operations are done.
  	 * Note also that wow_suspend must return in ~2.5sec, before
  	 * watchdog is triggered.
  	 */
  	if (priv->channel_switch_in_progress)
  		goto revert1;
  
  	/* Do not suspend when join is pending */
  	if (priv->join_pending)
  		goto revert1;
  
  	/* Do not suspend when scanning */
  	if (down_trylock(&priv->scan.lock))
  		goto revert1;
  
  	/* Lock TX. */
  	wsm_lock_tx_async(priv);
  
  	/* Wait to avoid possible race with bh code.
  	 * But do not wait too long...
  	 */
  	if (wait_event_timeout(priv->bh_evt_wq,
  			       !priv->hw_bufs_used, HZ / 10) <= 0)
  		goto revert2;
  
  	/* Set UDP filter */
  	wsm_set_udp_port_filter(priv, &cw1200_udp_port_filter_on.hdr);
  
  	/* Set ethernet frame type filter */
  	wsm_set_ether_type_filter(priv, &cw1200_ether_type_filter_on.hdr);
  
  	/* Allocate state */
  	state = kzalloc(sizeof(struct cw1200_suspend_state), GFP_KERNEL);
  	if (!state)
  		goto revert3;
  
  	/* Change to legacy PS while going to suspend */
  	if (!priv->vif->p2p &&
  	    priv->join_status == CW1200_JOIN_STATUS_STA &&
  	    priv->powersave_mode.mode != WSM_PSM_PS) {
  		state->prev_ps_mode = priv->powersave_mode.mode;
  		priv->powersave_mode.mode = WSM_PSM_PS;
  		cw1200_set_pm(priv, &priv->powersave_mode);
  		if (wait_event_interruptible_timeout(priv->ps_mode_switch_done,
  						     !priv->ps_mode_switch_in_progress, 1*HZ) <= 0) {
  			goto revert4;
  		}
  	}
  
  	/* Store delayed work states. */
  	state->bss_loss_tmo =
  		cw1200_suspend_work(&priv->bss_loss_work);
  	state->join_tmo =
  		cw1200_suspend_work(&priv->join_timeout);
  	state->direct_probe =
  		cw1200_suspend_work(&priv->scan.probe_work);
  	state->link_id_gc =
  		cw1200_suspend_work(&priv->link_id_gc_work);
  
  	cancel_delayed_work_sync(&priv->clear_recent_scan_work);
  	atomic_set(&priv->recent_scan, 0);
  
  	/* Enable beacon skipping */
  	if (priv->join_status == CW1200_JOIN_STATUS_STA &&
  	    priv->join_dtim_period &&
  	    !priv->has_multicast_subscription) {
  		state->beacon_skipping = true;
  		wsm_set_beacon_wakeup_period(priv,
  					     priv->join_dtim_period,
  					     CW1200_BEACON_SKIPPING_MULTIPLIER * priv->join_dtim_period);
  	}
  
  	/* Stop serving thread */
  	if (cw1200_bh_suspend(priv))
  		goto revert5;
  
  	ret = timer_pending(&priv->mcast_timeout);
  	if (ret)
  		goto revert6;
  
  	/* Store suspend state */
  	pm_state->suspend_state = state;
  
  	/* Enable IRQ wake */
  	ret = priv->hwbus_ops->power_mgmt(priv->hwbus_priv, true);
  	if (ret) {
  		wiphy_err(priv->hw->wiphy,
  			  "PM request failed: %d. WoW is disabled.
  ", ret);
  		cw1200_wow_resume(hw);
  		return -EBUSY;
  	}
  
  	/* Force resume if event is coming from the device. */
  	if (atomic_read(&priv->bh_rx)) {
  		cw1200_wow_resume(hw);
  		return -EAGAIN;
  	}
  
  	return 0;
  
  revert6:
  	WARN_ON(cw1200_bh_resume(priv));
  revert5:
  	cw1200_resume_work(priv, &priv->bss_loss_work,
  			   state->bss_loss_tmo);
  	cw1200_resume_work(priv, &priv->join_timeout,
  			   state->join_tmo);
  	cw1200_resume_work(priv, &priv->scan.probe_work,
  			   state->direct_probe);
  	cw1200_resume_work(priv, &priv->link_id_gc_work,
  			   state->link_id_gc);
  revert4:
  	kfree(state);
  revert3:
  	wsm_set_udp_port_filter(priv, &cw1200_udp_port_filter_off);
  	wsm_set_ether_type_filter(priv, &cw1200_ether_type_filter_off);
  revert2:
  	wsm_unlock_tx(priv);
  	up(&priv->scan.lock);
  revert1:
  	mutex_unlock(&priv->conf_mutex);
  	return -EBUSY;
  }
  
  int cw1200_wow_resume(struct ieee80211_hw *hw)
  {
  	struct cw1200_common *priv = hw->priv;
  	struct cw1200_pm_state *pm_state = &priv->pm_state;
  	struct cw1200_suspend_state *state;
  
  	state = pm_state->suspend_state;
  	pm_state->suspend_state = NULL;
  
  	/* Disable IRQ wake */
  	priv->hwbus_ops->power_mgmt(priv->hwbus_priv, false);
  
  	/* Scan.lock must be released before BH is resumed other way
  	 * in case when BSS_LOST command arrived the processing of the
  	 * command will be delayed.
  	 */
  	up(&priv->scan.lock);
  
  	/* Resume BH thread */
  	WARN_ON(cw1200_bh_resume(priv));
  
  	/* Restores previous PS mode */
  	if (!priv->vif->p2p && priv->join_status == CW1200_JOIN_STATUS_STA) {
  		priv->powersave_mode.mode = state->prev_ps_mode;
  		cw1200_set_pm(priv, &priv->powersave_mode);
  	}
  
  	if (state->beacon_skipping) {
  		wsm_set_beacon_wakeup_period(priv, priv->beacon_int *
  					     priv->join_dtim_period >
  					     MAX_BEACON_SKIP_TIME_MS ? 1 :
  					     priv->join_dtim_period, 0);
  		state->beacon_skipping = false;
  	}
  
  	/* Resume delayed work */
  	cw1200_resume_work(priv, &priv->bss_loss_work,
  			   state->bss_loss_tmo);
  	cw1200_resume_work(priv, &priv->join_timeout,
  			   state->join_tmo);
  	cw1200_resume_work(priv, &priv->scan.probe_work,
  			   state->direct_probe);
  	cw1200_resume_work(priv, &priv->link_id_gc_work,
  			   state->link_id_gc);
  
  	/* Remove UDP port filter */
  	wsm_set_udp_port_filter(priv, &cw1200_udp_port_filter_off);
  
  	/* Remove ethernet frame type filter */
  	wsm_set_ether_type_filter(priv, &cw1200_ether_type_filter_off);
  
  	/* Unlock datapath */
  	wsm_unlock_tx(priv);
  
  	/* Unlock configuration mutex */
  	mutex_unlock(&priv->conf_mutex);
  
  	/* Free memory */
  	kfree(state);
  
  	return 0;
  }