/*
 * 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);

	init_timer(&pm->stay_awake);
	pm->stay_awake.data = (unsigned long)pm;
	pm->stay_awake.function = cw1200_pm_stay_awake_tmo;

	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.\n");
		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.\n", 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;
}