[deliverable/linux.git] / drivers / net / wireless / rt2x00 / rt2x00link.c

/*
	Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com>
	<http://rt2x00.serialmonkey.com>

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	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.,
	59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*
	Module: rt2x00lib
	Abstract: rt2x00 generic link tuning routines.
 */

#include <linux/kernel.h>
#include <linux/module.h>

#include "rt2x00.h"
#include "rt2x00lib.h"

/*
 * When we lack RSSI information return something less then -80 to
 * tell the driver to tune the device to maximum sensitivity.
 */
#define DEFAULT_RSSI		-128

/*
 * Helper struct and macro to work with moving/walking averages.
 * When adding a value to the average value the following calculation
 * is needed:
 *
 *        avg_rssi = ((avg_rssi * 7) + rssi) / 8;
 *
 * The advantage of this approach is that we only need 1 variable
 * to store the average in (No need for a count and a total).
 * But more importantly, normal average values will over time
 * move less and less towards newly added values this results
 * that with link tuning, the device can have a very good RSSI
 * for a few minutes but when the device is moved away from the AP
 * the average will not decrease fast enough to compensate.
 * The walking average compensates this and will move towards
 * the new values correctly allowing a effective link tuning,
 * the speed of the average moving towards other values depends
 * on the value for the number of samples. The higher the number
 * of samples, the slower the average will move.
 * We use two variables to keep track of the average value to
 * compensate for the rounding errors. This can be a significant
 * error (>5dBm) if the factor is too low.
 */
#define AVG_SAMPLES	8
#define AVG_FACTOR	1000
#define MOVING_AVERAGE(__avg, __val) \
({ \
	struct avg_val __new; \
	__new.avg_weight = \
	    (__avg).avg_weight  ? \
		((((__avg).avg_weight * ((AVG_SAMPLES) - 1)) + \
		  ((__val) * (AVG_FACTOR))) / \
		 (AVG_SAMPLES)) : \
		((__val) * (AVG_FACTOR)); \
	__new.avg = __new.avg_weight / (AVG_FACTOR); \
	__new; \
})

static int rt2x00link_antenna_get_link_rssi(struct rt2x00_dev *rt2x00dev)
{
	struct link_ant *ant = &rt2x00dev->link.ant;

	if (ant->rssi_ant.avg && rt2x00dev->link.qual.rx_success)
		return ant->rssi_ant.avg;
	return DEFAULT_RSSI;
}

static int rt2x00link_antenna_get_rssi_history(struct rt2x00_dev *rt2x00dev)
{
	struct link_ant *ant = &rt2x00dev->link.ant;

	if (ant->rssi_history)
		return ant->rssi_history;
	return DEFAULT_RSSI;
}

static void rt2x00link_antenna_update_rssi_history(struct rt2x00_dev *rt2x00dev,
						   int rssi)
{
	struct link_ant *ant = &rt2x00dev->link.ant;
	ant->rssi_history = rssi;
}

static void rt2x00link_antenna_reset(struct rt2x00_dev *rt2x00dev)
{
	rt2x00dev->link.ant.rssi_ant.avg = 0;
	rt2x00dev->link.ant.rssi_ant.avg_weight = 0;
}

static void rt2x00lib_antenna_diversity_sample(struct rt2x00_dev *rt2x00dev)
{
	struct link_ant *ant = &rt2x00dev->link.ant;
	struct antenna_setup new_ant;
	int other_antenna;

	int sample_current = rt2x00link_antenna_get_link_rssi(rt2x00dev);
	int sample_other = rt2x00link_antenna_get_rssi_history(rt2x00dev);

	memcpy(&new_ant, &ant->active, sizeof(new_ant));

	/*
	 * We are done sampling. Now we should evaluate the results.
	 */
	ant->flags &= ~ANTENNA_MODE_SAMPLE;

	/*
	 * During the last period we have sampled the RSSI
	 * from both antennas. It now is time to determine
	 * which antenna demonstrated the best performance.
	 * When we are already on the antenna with the best
	 * performance, just create a good starting point
	 * for the history and we are done.
	 */
	if (sample_current >= sample_other) {
		rt2x00link_antenna_update_rssi_history(rt2x00dev,
			sample_current);
		return;
	}

	other_antenna = (ant->active.rx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;

	if (ant->flags & ANTENNA_RX_DIVERSITY)
		new_ant.rx = other_antenna;

	if (ant->flags & ANTENNA_TX_DIVERSITY)
		new_ant.tx = other_antenna;

	rt2x00lib_config_antenna(rt2x00dev, new_ant);
}

static void rt2x00lib_antenna_diversity_eval(struct rt2x00_dev *rt2x00dev)
{
	struct link_ant *ant = &rt2x00dev->link.ant;
	struct antenna_setup new_ant;
	int rssi_curr;
	int rssi_old;

	memcpy(&new_ant, &ant->active, sizeof(new_ant));

	/*
	 * Get current RSSI value along with the historical value,
	 * after that update the history with the current value.
	 */
	rssi_curr = rt2x00link_antenna_get_link_rssi(rt2x00dev);
	rssi_old = rt2x00link_antenna_get_rssi_history(rt2x00dev);
	rt2x00link_antenna_update_rssi_history(rt2x00dev, rssi_curr);

	/*
	 * Legacy driver indicates that we should swap antenna's
	 * when the difference in RSSI is greater that 5. This
	 * also should be done when the RSSI was actually better
	 * then the previous sample.
	 * When the difference exceeds the threshold we should
	 * sample the rssi from the other antenna to make a valid
	 * comparison between the 2 antennas.
	 */
	if (abs(rssi_curr - rssi_old) < 5)
		return;

	ant->flags |= ANTENNA_MODE_SAMPLE;

	if (ant->flags & ANTENNA_RX_DIVERSITY)
		new_ant.rx = (new_ant.rx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;

	if (ant->flags & ANTENNA_TX_DIVERSITY)
		new_ant.tx = (new_ant.tx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;

	rt2x00lib_config_antenna(rt2x00dev, new_ant);
}

static bool rt2x00lib_antenna_diversity(struct rt2x00_dev *rt2x00dev)
{
	struct link_ant *ant = &rt2x00dev->link.ant;

	/*
	 * Determine if software diversity is enabled for
	 * either the TX or RX antenna (or both).
	 * Always perform this check since within the link
	 * tuner interval the configuration might have changed.
	 */
	ant->flags &= ~ANTENNA_RX_DIVERSITY;
	ant->flags &= ~ANTENNA_TX_DIVERSITY;

	if (rt2x00dev->default_ant.rx == ANTENNA_SW_DIVERSITY)
		ant->flags |= ANTENNA_RX_DIVERSITY;
	if (rt2x00dev->default_ant.tx == ANTENNA_SW_DIVERSITY)
		ant->flags |= ANTENNA_TX_DIVERSITY;

	if (!(ant->flags & ANTENNA_RX_DIVERSITY) &&
	    !(ant->flags & ANTENNA_TX_DIVERSITY)) {
		ant->flags = 0;
		return true;
	}

	/*
	 * If we have only sampled the data over the last period
	 * we should now harvest the data. Otherwise just evaluate
	 * the data. The latter should only be performed once
	 * every 2 seconds.
	 */
	if (ant->flags & ANTENNA_MODE_SAMPLE) {
		rt2x00lib_antenna_diversity_sample(rt2x00dev);
		return true;
	} else if (rt2x00dev->link.count & 1) {
		rt2x00lib_antenna_diversity_eval(rt2x00dev);
		return true;
	}

	return false;
}

void rt2x00link_update_stats(struct rt2x00_dev *rt2x00dev,
			     struct sk_buff *skb,
			     struct rxdone_entry_desc *rxdesc)
{
	struct link *link = &rt2x00dev->link;
	struct link_qual *qual = &rt2x00dev->link.qual;
	struct link_ant *ant = &rt2x00dev->link.ant;
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;

	/*
	 * No need to update the stats for !=STA interfaces
	 */
	if (!rt2x00dev->intf_sta_count)
		return;

	/*
	 * Frame was received successfully since non-succesfull
	 * frames would have been dropped by the hardware.
	 */
	qual->rx_success++;

	/*
	 * We are only interested in quality statistics from
	 * beacons which came from the BSS which we are
	 * associated with.
	 */
	if (!ieee80211_is_beacon(hdr->frame_control) ||
	    !(rxdesc->dev_flags & RXDONE_MY_BSS))
		return;

	/*
	 * Update global RSSI
	 */
	link->avg_rssi = MOVING_AVERAGE(link->avg_rssi, rxdesc->rssi);

	/*
	 * Update antenna RSSI
	 */
	ant->rssi_ant = MOVING_AVERAGE(ant->rssi_ant, rxdesc->rssi);
}

void rt2x00link_start_tuner(struct rt2x00_dev *rt2x00dev)
{
	struct link *link = &rt2x00dev->link;

	/*
	 * Link tuning should only be performed when
	 * an active sta interface exists. AP interfaces
	 * don't need link tuning and monitor mode interfaces
	 * should never have to work with link tuners.
	 */
	if (!rt2x00dev->intf_sta_count)
		return;

	/**
	 * While scanning, link tuning is disabled. By default
	 * the most sensitive settings will be used to make sure
	 * that all beacons and probe responses will be recieved
	 * during the scan.
	 */
	if (test_bit(DEVICE_STATE_SCANNING, &rt2x00dev->flags))
		return;

	rt2x00link_reset_tuner(rt2x00dev, false);

	if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
		ieee80211_queue_delayed_work(rt2x00dev->hw,
					     &link->work, LINK_TUNE_INTERVAL);
}

void rt2x00link_stop_tuner(struct rt2x00_dev *rt2x00dev)
{
	cancel_delayed_work_sync(&rt2x00dev->link.work);
}

void rt2x00link_reset_tuner(struct rt2x00_dev *rt2x00dev, bool antenna)
{
	struct link_qual *qual = &rt2x00dev->link.qual;
	u8 vgc_level = qual->vgc_level_reg;

	if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
		return;

	/*
	 * Reset link information.
	 * Both the currently active vgc level as well as
	 * the link tuner counter should be reset. Resetting
	 * the counter is important for devices where the
	 * device should only perform link tuning during the
	 * first minute after being enabled.
	 */
	rt2x00dev->link.count = 0;
	memset(qual, 0, sizeof(*qual));

	/*
	 * Restore the VGC level as stored in the registers,
	 * the driver can use this to determine if the register
	 * must be updated during reset or not.
	 */
	qual->vgc_level_reg = vgc_level;

	/*
	 * Reset the link tuner.
	 */
	rt2x00dev->ops->lib->reset_tuner(rt2x00dev, qual);

	if (antenna)
		rt2x00link_antenna_reset(rt2x00dev);
}

static void rt2x00link_reset_qual(struct rt2x00_dev *rt2x00dev)
{
	struct link_qual *qual = &rt2x00dev->link.qual;

	qual->rx_success = 0;
	qual->rx_failed = 0;
	qual->tx_success = 0;
	qual->tx_failed = 0;
}

static void rt2x00link_tuner(struct work_struct *work)
{
	struct rt2x00_dev *rt2x00dev =
	    container_of(work, struct rt2x00_dev, link.work.work);
	struct link *link = &rt2x00dev->link;
	struct link_qual *qual = &rt2x00dev->link.qual;

	/*
	 * When the radio is shutting down we should
	 * immediately cease all link tuning.
	 */
	if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags) ||
	    test_bit(DEVICE_STATE_SCANNING, &rt2x00dev->flags))
		return;

	/*
	 * Update statistics.
	 */
	rt2x00dev->ops->lib->link_stats(rt2x00dev, qual);
	rt2x00dev->low_level_stats.dot11FCSErrorCount += qual->rx_failed;

	/*
	 * Update quality RSSI for link tuning,
	 * when we have received some frames and we managed to
	 * collect the RSSI data we could use this. Otherwise we
	 * must fallback to the default RSSI value.
	 */
	if (!link->avg_rssi.avg || !qual->rx_success)
		qual->rssi = DEFAULT_RSSI;
	else
		qual->rssi = link->avg_rssi.avg;

	/*
	 * Check if link tuning is supported by the hardware, some hardware
	 * do not support link tuning at all, while other devices can disable
	 * the feature from the EEPROM.
	 */
	if (test_bit(DRIVER_SUPPORT_LINK_TUNING, &rt2x00dev->flags))
		rt2x00dev->ops->lib->link_tuner(rt2x00dev, qual, link->count);

	/*
	 * Send a signal to the led to update the led signal strength.
	 */
	rt2x00leds_led_quality(rt2x00dev, qual->rssi);

	/*
	 * Evaluate antenna setup, make this the last step when
	 * rt2x00lib_antenna_diversity made changes the quality
	 * statistics will be reset.
	 */
	if (rt2x00lib_antenna_diversity(rt2x00dev))
		rt2x00link_reset_qual(rt2x00dev);

	/*
	 * Increase tuner counter, and reschedule the next link tuner run.
	 */
	link->count++;

	if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
		ieee80211_queue_delayed_work(rt2x00dev->hw,
					     &link->work, LINK_TUNE_INTERVAL);
}

void rt2x00link_start_watchdog(struct rt2x00_dev *rt2x00dev)
{
	struct link *link = &rt2x00dev->link;

	if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags) &&
	    rt2x00dev->ops->lib->watchdog)
		ieee80211_queue_delayed_work(rt2x00dev->hw,
					     &link->watchdog_work,
					     WATCHDOG_INTERVAL);
}

void rt2x00link_stop_watchdog(struct rt2x00_dev *rt2x00dev)
{
	cancel_delayed_work_sync(&rt2x00dev->link.watchdog_work);
}

static void rt2x00link_watchdog(struct work_struct *work)
{
	struct rt2x00_dev *rt2x00dev =
	    container_of(work, struct rt2x00_dev, link.watchdog_work.work);
	struct link *link = &rt2x00dev->link;

	/*
	 * When the radio is shutting down we should
	 * immediately cease the watchdog monitoring.
	 */
	if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
		return;

	rt2x00dev->ops->lib->watchdog(rt2x00dev);

	if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
		ieee80211_queue_delayed_work(rt2x00dev->hw,
					     &link->watchdog_work,
					     WATCHDOG_INTERVAL);
}

void rt2x00link_start_agc(struct rt2x00_dev *rt2x00dev)
{
	struct link *link = &rt2x00dev->link;

	if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags) &&
	    rt2x00dev->ops->lib->gain_calibration)
		ieee80211_queue_delayed_work(rt2x00dev->hw,
					     &link->agc_work,
					     AGC_INTERVAL);
}

void rt2x00link_stop_agc(struct rt2x00_dev *rt2x00dev)
{
	cancel_delayed_work_sync(&rt2x00dev->link.agc_work);
}

static void rt2x00link_agc(struct work_struct *work)
{
	struct rt2x00_dev *rt2x00dev =
	    container_of(work, struct rt2x00_dev, link.agc_work.work);
	struct link *link = &rt2x00dev->link;

	/*
	 * When the radio is shutting down we should
	 * immediately cease the watchdog monitoring.
	 */
	if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
		return;

	rt2x00dev->ops->lib->gain_calibration(rt2x00dev);

	if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
		ieee80211_queue_delayed_work(rt2x00dev->hw,
					     &link->agc_work,
					     AGC_INTERVAL);
}

void rt2x00link_register(struct rt2x00_dev *rt2x00dev)
{
	INIT_DELAYED_WORK(&rt2x00dev->link.agc_work, rt2x00link_agc);
	INIT_DELAYED_WORK(&rt2x00dev->link.watchdog_work, rt2x00link_watchdog);
	INIT_DELAYED_WORK(&rt2x00dev->link.work, rt2x00link_tuner);
}
Commit	Line	Data
84e3196f	1	/*
9c9a0d14	2	Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com>
84e3196f ID	3	<http://rt2x00.serialmonkey.com>
	4
	5	This program is free software; you can redistribute it and/or modify
	6	it under the terms of the GNU General Public License as published by
	7	the Free Software Foundation; either version 2 of the License, or
	8	(at your option) any later version.
	9
	10	This program is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	GNU General Public License for more details.
	14
	15	You should have received a copy of the GNU General Public License
	16	along with this program; if not, write to the
	17	Free Software Foundation, Inc.,
	18	59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	19	*/
	20
	21	/*
	22	Module: rt2x00lib
	23	Abstract: rt2x00 generic link tuning routines.
	24	*/
	25
	26	#include <linux/kernel.h>
	27	#include <linux/module.h>
	28
	29	#include "rt2x00.h"
	30	#include "rt2x00lib.h"
	31
5352ff65 ID	32	/*
	33	* When we lack RSSI information return something less then -80 to
	34	* tell the driver to tune the device to maximum sensitivity.
	35	*/
	36	#define DEFAULT_RSSI -128
	37
66679a65 LE	38	/*
66679a65 LE	39	* Helper struct and macro to work with moving/walking averages.
5352ff65 ID	40	* When adding a value to the average value the following calculation
	41	* is needed:
	42	*
	43	* avg_rssi = ((avg_rssi * 7) + rssi) / 8;
	44	*
	45	* The advantage of this approach is that we only need 1 variable
	46	* to store the average in (No need for a count and a total).
	47	* But more importantly, normal average values will over time
	48	* move less and less towards newly added values this results
	49	* that with link tuning, the device can have a very good RSSI
	50	* for a few minutes but when the device is moved away from the AP
	51	* the average will not decrease fast enough to compensate.
	52	* The walking average compensates this and will move towards
66679a65 LE	53	* the new values correctly allowing a effective link tuning,
	54	* the speed of the average moving towards other values depends
	55	* on the value for the number of samples. The higher the number
	56	* of samples, the slower the average will move.
	57	* We use two variables to keep track of the average value to
	58	* compensate for the rounding errors. This can be a significant
	59	* error (>5dBm) if the factor is too low.
5352ff65	60	*/
66679a65 LE	61	#define AVG_SAMPLES 8
	62	#define AVG_FACTOR 1000
	63	#define MOVING_AVERAGE(__avg, __val) \
	64	({ \
	65	struct avg_val __new; \
	66	__new.avg_weight = \
	67	(__avg).avg_weight ? \
	68	((((__avg).avg_weight * ((AVG_SAMPLES) - 1)) + \
	69	((__val) * (AVG_FACTOR))) / \
027e8fd1	70	(AVG_SAMPLES)) : \
66679a65 LE	71	((__val) * (AVG_FACTOR)); \
	72	__new.avg = __new.avg_weight / (AVG_FACTOR); \
	73	__new; \
	74	})
5352ff65	75
84e3196f ID	76	static int rt2x00link_antenna_get_link_rssi(struct rt2x00_dev *rt2x00dev)
	77	{
	78	struct link_ant *ant = &rt2x00dev->link.ant;
	79
66679a65 LE	80	if (ant->rssi_ant.avg && rt2x00dev->link.qual.rx_success)
66679a65 LE	81	return ant->rssi_ant.avg;
84e3196f ID	82	return DEFAULT_RSSI;
	83	}
	84
193df183	85	static int rt2x00link_antenna_get_rssi_history(struct rt2x00_dev *rt2x00dev)
84e3196f ID	86	{
	87	struct link_ant *ant = &rt2x00dev->link.ant;
	88
193df183 LE	89	if (ant->rssi_history)
193df183 LE	90	return ant->rssi_history;
84e3196f ID	91	return DEFAULT_RSSI;
84e3196f ID	92	}
84e3196f ID	93
84e3196f ID	94	static void rt2x00link_antenna_update_rssi_history(struct rt2x00_dev *rt2x00dev,
84e3196f ID	95	int rssi)
	96	{
	97	struct link_ant *ant = &rt2x00dev->link.ant;
193df183	98	ant->rssi_history = rssi;
84e3196f	99	}
84e3196f ID	100
	101	static void rt2x00link_antenna_reset(struct rt2x00_dev *rt2x00dev)
	102	{
66679a65 LE	103	rt2x00dev->link.ant.rssi_ant.avg = 0;
66679a65 LE	104	rt2x00dev->link.ant.rssi_ant.avg_weight = 0;
84e3196f ID	105	}
	106
	107	static void rt2x00lib_antenna_diversity_sample(struct rt2x00_dev *rt2x00dev)
	108	{
	109	struct link_ant *ant = &rt2x00dev->link.ant;
	110	struct antenna_setup new_ant;
193df183 LE	111	int other_antenna;
	112
	113	int sample_current = rt2x00link_antenna_get_link_rssi(rt2x00dev);
	114	int sample_other = rt2x00link_antenna_get_rssi_history(rt2x00dev);
84e3196f ID	115
	116	memcpy(&new_ant, &ant->active, sizeof(new_ant));
	117
	118	/*
	119	* We are done sampling. Now we should evaluate the results.
	120	*/
	121	ant->flags &= ~ANTENNA_MODE_SAMPLE;
	122
	123	/*
	124	* During the last period we have sampled the RSSI
49513481	125	* from both antennas. It now is time to determine
84e3196f ID	126	* which antenna demonstrated the best performance.
84e3196f ID	127	* When we are already on the antenna with the best
193df183 LE	128	* performance, just create a good starting point
193df183 LE	129	* for the history and we are done.
84e3196f	130	*/
193df183 LE	131	if (sample_current >= sample_other) {
	132	rt2x00link_antenna_update_rssi_history(rt2x00dev,
	133	sample_current);
84e3196f	134	return;
193df183 LE	135	}
	136
	137	other_antenna = (ant->active.rx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;
84e3196f ID	138
84e3196f ID	139	if (ant->flags & ANTENNA_RX_DIVERSITY)
193df183	140	new_ant.rx = other_antenna;
84e3196f ID	141
84e3196f ID	142	if (ant->flags & ANTENNA_TX_DIVERSITY)
193df183	143	new_ant.tx = other_antenna;
84e3196f	144
eb87eaac	145	rt2x00lib_config_antenna(rt2x00dev, new_ant);
84e3196f ID	146	}
	147
	148	static void rt2x00lib_antenna_diversity_eval(struct rt2x00_dev *rt2x00dev)
	149	{
	150	struct link_ant *ant = &rt2x00dev->link.ant;
	151	struct antenna_setup new_ant;
	152	int rssi_curr;
	153	int rssi_old;
	154
	155	memcpy(&new_ant, &ant->active, sizeof(new_ant));
	156
	157	/*
	158	* Get current RSSI value along with the historical value,
	159	* after that update the history with the current value.
	160	*/
	161	rssi_curr = rt2x00link_antenna_get_link_rssi(rt2x00dev);
193df183 LE	162	rssi_old = rt2x00link_antenna_get_rssi_history(rt2x00dev);
193df183 LE	163	rt2x00link_antenna_update_rssi_history(rt2x00dev, rssi_curr);
84e3196f ID	164
	165	/*
	166	* Legacy driver indicates that we should swap antenna's
	167	* when the difference in RSSI is greater that 5. This
	168	* also should be done when the RSSI was actually better
	169	* then the previous sample.
	170	* When the difference exceeds the threshold we should
	171	* sample the rssi from the other antenna to make a valid
	172	* comparison between the 2 antennas.
	173	*/
	174	if (abs(rssi_curr - rssi_old) < 5)
	175	return;
	176
	177	ant->flags \|= ANTENNA_MODE_SAMPLE;
	178
	179	if (ant->flags & ANTENNA_RX_DIVERSITY)
	180	new_ant.rx = (new_ant.rx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;
	181
	182	if (ant->flags & ANTENNA_TX_DIVERSITY)
	183	new_ant.tx = (new_ant.tx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;
	184
eb87eaac	185	rt2x00lib_config_antenna(rt2x00dev, new_ant);
84e3196f ID	186	}
84e3196f ID	187
193df183	188	static bool rt2x00lib_antenna_diversity(struct rt2x00_dev *rt2x00dev)
84e3196f ID	189	{
	190	struct link_ant *ant = &rt2x00dev->link.ant;
	191
	192	/*
	193	* Determine if software diversity is enabled for
	194	* either the TX or RX antenna (or both).
	195	* Always perform this check since within the link
	196	* tuner interval the configuration might have changed.
	197	*/
85f4d648 LE	198	ant->flags &= ~ANTENNA_RX_DIVERSITY;
85f4d648 LE	199	ant->flags &= ~ANTENNA_TX_DIVERSITY;
84e3196f ID	200
84e3196f ID	201	if (rt2x00dev->default_ant.rx == ANTENNA_SW_DIVERSITY)
85f4d648	202	ant->flags \|= ANTENNA_RX_DIVERSITY;
84e3196f	203	if (rt2x00dev->default_ant.tx == ANTENNA_SW_DIVERSITY)
85f4d648	204	ant->flags \|= ANTENNA_TX_DIVERSITY;
84e3196f ID	205
	206	if (!(ant->flags & ANTENNA_RX_DIVERSITY) &&
	207	!(ant->flags & ANTENNA_TX_DIVERSITY)) {
	208	ant->flags = 0;
193df183	209	return true;
84e3196f ID	210	}
	211
	212	/*
	213	* If we have only sampled the data over the last period
	214	* we should now harvest the data. Otherwise just evaluate
	215	* the data. The latter should only be performed once
	216	* every 2 seconds.
	217	*/
193df183	218	if (ant->flags & ANTENNA_MODE_SAMPLE) {
84e3196f	219	rt2x00lib_antenna_diversity_sample(rt2x00dev);
193df183 LE	220	return true;
193df183 LE	221	} else if (rt2x00dev->link.count & 1) {
84e3196f	222	rt2x00lib_antenna_diversity_eval(rt2x00dev);
193df183 LE	223	return true;
	224	}
	225
	226	return false;
84e3196f ID	227	}
	228
	229	void rt2x00link_update_stats(struct rt2x00_dev *rt2x00dev,
	230	struct sk_buff *skb,
	231	struct rxdone_entry_desc *rxdesc)
	232	{
5352ff65	233	struct link *link = &rt2x00dev->link;
84e3196f ID	234	struct link_qual *qual = &rt2x00dev->link.qual;
	235	struct link_ant *ant = &rt2x00dev->link.ant;
	236	struct ieee80211_hdr hdr = (struct ieee80211_hdr )skb->data;
84e3196f	237
a23c2208 HS	238	/*
	239	* No need to update the stats for !=STA interfaces
	240	*/
	241	if (!rt2x00dev->intf_sta_count)
	242	return;
	243
84e3196f ID	244	/*
	245	* Frame was received successfully since non-succesfull
	246	* frames would have been dropped by the hardware.
	247	*/
	248	qual->rx_success++;
	249
	250	/*
	251	* We are only interested in quality statistics from
	252	* beacons which came from the BSS which we are
	253	* associated with.
	254	*/
	255	if (!ieee80211_is_beacon(hdr->frame_control) \|\|
	256	!(rxdesc->dev_flags & RXDONE_MY_BSS))
	257	return;
	258
	259	/*
	260	* Update global RSSI
	261	*/
66679a65	262	link->avg_rssi = MOVING_AVERAGE(link->avg_rssi, rxdesc->rssi);
84e3196f ID	263
	264	/*
	265	* Update antenna RSSI
	266	*/
66679a65	267	ant->rssi_ant = MOVING_AVERAGE(ant->rssi_ant, rxdesc->rssi);
84e3196f ID	268	}
84e3196f ID	269
84e3196f ID	270	void rt2x00link_start_tuner(struct rt2x00_dev *rt2x00dev)
84e3196f ID	271	{
5352ff65	272	struct link *link = &rt2x00dev->link;
84e3196f ID	273
	274	/*
	275	* Link tuning should only be performed when
8654b79f HS	276	* an active sta interface exists. AP interfaces
	277	* don't need link tuning and monitor mode interfaces
	278	* should never have to work with link tuners.
84e3196f	279	*/
8654b79f	280	if (!rt2x00dev->intf_sta_count)
84e3196f ID	281	return;
84e3196f ID	282
d8147f9d ID	283	/**
	284	* While scanning, link tuning is disabled. By default
	285	* the most sensitive settings will be used to make sure
	286	* that all beacons and probe responses will be recieved
	287	* during the scan.
	288	*/
	289	if (test_bit(DEVICE_STATE_SCANNING, &rt2x00dev->flags))
	290	return;
	291
84e3196f ID	292	rt2x00link_reset_tuner(rt2x00dev, false);
84e3196f ID	293
66f84d65 SC	294	if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
	295	ieee80211_queue_delayed_work(rt2x00dev->hw,
	296	&link->work, LINK_TUNE_INTERVAL);
84e3196f ID	297	}
	298
	299	void rt2x00link_stop_tuner(struct rt2x00_dev *rt2x00dev)
	300	{
	301	cancel_delayed_work_sync(&rt2x00dev->link.work);
	302	}
	303
	304	void rt2x00link_reset_tuner(struct rt2x00_dev *rt2x00dev, bool antenna)
	305	{
5352ff65	306	struct link_qual *qual = &rt2x00dev->link.qual;
223dcc26	307	u8 vgc_level = qual->vgc_level_reg;
5352ff65	308
84e3196f ID	309	if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
	310	return;
	311
	312	/*
	313	* Reset link information.
	314	* Both the currently active vgc level as well as
	315	* the link tuner counter should be reset. Resetting
	316	* the counter is important for devices where the
	317	* device should only perform link tuning during the
	318	* first minute after being enabled.
	319	*/
	320	rt2x00dev->link.count = 0;
5352ff65	321	memset(qual, 0, sizeof(*qual));
84e3196f	322
223dcc26 ID	323	/*
	324	* Restore the VGC level as stored in the registers,
	325	* the driver can use this to determine if the register
	326	* must be updated during reset or not.
	327	*/
	328	qual->vgc_level_reg = vgc_level;
	329
84e3196f ID	330	/*
	331	* Reset the link tuner.
	332	*/
5352ff65	333	rt2x00dev->ops->lib->reset_tuner(rt2x00dev, qual);
84e3196f ID	334
	335	if (antenna)
	336	rt2x00link_antenna_reset(rt2x00dev);
	337	}
	338
a57e2e84	339	static void rt2x00link_reset_qual(struct rt2x00_dev *rt2x00dev)
64abd803 ID	340	{
	341	struct link_qual *qual = &rt2x00dev->link.qual;
	342
	343	qual->rx_success = 0;
	344	qual->rx_failed = 0;
	345	qual->tx_success = 0;
	346	qual->tx_failed = 0;
	347	}
	348
84e3196f ID	349	static void rt2x00link_tuner(struct work_struct *work)
	350	{
	351	struct rt2x00_dev *rt2x00dev =
	352	container_of(work, struct rt2x00_dev, link.work.work);
5352ff65	353	struct link *link = &rt2x00dev->link;
84e3196f ID	354	struct link_qual *qual = &rt2x00dev->link.qual;
	355
	356	/*
	357	* When the radio is shutting down we should
	358	* immediately cease all link tuning.
	359	*/
d8147f9d ID	360	if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags) \|\|
d8147f9d ID	361	test_bit(DEVICE_STATE_SCANNING, &rt2x00dev->flags))
84e3196f ID	362	return;
	363
	364	/*
	365	* Update statistics.
	366	*/
	367	rt2x00dev->ops->lib->link_stats(rt2x00dev, qual);
	368	rt2x00dev->low_level_stats.dot11FCSErrorCount += qual->rx_failed;
	369
5352ff65 ID	370	/*
	371	* Update quality RSSI for link tuning,
	372	* when we have received some frames and we managed to
	373	* collect the RSSI data we could use this. Otherwise we
	374	* must fallback to the default RSSI value.
	375	*/
66679a65	376	if (!link->avg_rssi.avg \|\| !qual->rx_success)
5352ff65 ID	377	qual->rssi = DEFAULT_RSSI;
5352ff65 ID	378	else
66679a65	379	qual->rssi = link->avg_rssi.avg;
5352ff65	380
84e3196f	381	/*
27df2a9c ID	382	* Check if link tuning is supported by the hardware, some hardware
	383	* do not support link tuning at all, while other devices can disable
	384	* the feature from the EEPROM.
84e3196f	385	*/
27df2a9c	386	if (test_bit(DRIVER_SUPPORT_LINK_TUNING, &rt2x00dev->flags))
5352ff65	387	rt2x00dev->ops->lib->link_tuner(rt2x00dev, qual, link->count);
84e3196f	388
84e3196f ID	389	/*
	390	* Send a signal to the led to update the led signal strength.
	391	*/
66679a65	392	rt2x00leds_led_quality(rt2x00dev, qual->rssi);
84e3196f ID	393
84e3196f ID	394	/*
193df183 LE	395	* Evaluate antenna setup, make this the last step when
	396	* rt2x00lib_antenna_diversity made changes the quality
	397	* statistics will be reset.
64abd803	398	*/
193df183 LE	399	if (rt2x00lib_antenna_diversity(rt2x00dev))
193df183 LE	400	rt2x00link_reset_qual(rt2x00dev);
64abd803	401
84e3196f ID	402	/*
	403	* Increase tuner counter, and reschedule the next link tuner run.
	404	*/
5352ff65	405	link->count++;
66f84d65 SC	406
	407	if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
	408	ieee80211_queue_delayed_work(rt2x00dev->hw,
	409	&link->work, LINK_TUNE_INTERVAL);
84e3196f ID	410	}
84e3196f ID	411
c965c74b ID	412	void rt2x00link_start_watchdog(struct rt2x00_dev *rt2x00dev)
	413	{
	414	struct link *link = &rt2x00dev->link;
	415
aca7305b HS	416	if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags) &&
	417	rt2x00dev->ops->lib->watchdog)
	418	ieee80211_queue_delayed_work(rt2x00dev->hw,
	419	&link->watchdog_work,
	420	WATCHDOG_INTERVAL);
c965c74b ID	421	}
	422
	423	void rt2x00link_stop_watchdog(struct rt2x00_dev *rt2x00dev)
	424	{
	425	cancel_delayed_work_sync(&rt2x00dev->link.watchdog_work);
	426	}
	427
	428	static void rt2x00link_watchdog(struct work_struct *work)
	429	{
	430	struct rt2x00_dev *rt2x00dev =
	431	container_of(work, struct rt2x00_dev, link.watchdog_work.work);
	432	struct link *link = &rt2x00dev->link;
	433
	434	/*
	435	* When the radio is shutting down we should
	436	* immediately cease the watchdog monitoring.
	437	*/
	438	if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
	439	return;
	440
	441	rt2x00dev->ops->lib->watchdog(rt2x00dev);
	442
	443	if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
0439f536 ID	444	ieee80211_queue_delayed_work(rt2x00dev->hw,
	445	&link->watchdog_work,
	446	WATCHDOG_INTERVAL);
c965c74b ID	447	}
c965c74b ID	448
9e33a355 HS	449	void rt2x00link_start_agc(struct rt2x00_dev *rt2x00dev)
	450	{
	451	struct link *link = &rt2x00dev->link;
	452
	453	if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags) &&
	454	rt2x00dev->ops->lib->gain_calibration)
	455	ieee80211_queue_delayed_work(rt2x00dev->hw,
	456	&link->agc_work,
	457	AGC_INTERVAL);
	458	}
	459
	460	void rt2x00link_stop_agc(struct rt2x00_dev *rt2x00dev)
	461	{
	462	cancel_delayed_work_sync(&rt2x00dev->link.agc_work);
	463	}
	464
	465	static void rt2x00link_agc(struct work_struct *work)
	466	{
	467	struct rt2x00_dev *rt2x00dev =
	468	container_of(work, struct rt2x00_dev, link.agc_work.work);
	469	struct link *link = &rt2x00dev->link;
	470
	471	/*
	472	* When the radio is shutting down we should
	473	* immediately cease the watchdog monitoring.
	474	*/
	475	if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
	476	return;
	477
	478	rt2x00dev->ops->lib->gain_calibration(rt2x00dev);
	479
	480	if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
	481	ieee80211_queue_delayed_work(rt2x00dev->hw,
	482	&link->agc_work,
	483	AGC_INTERVAL);
	484	}
	485
84e3196f ID	486	void rt2x00link_register(struct rt2x00_dev *rt2x00dev)
84e3196f ID	487	{
9e33a355	488	INIT_DELAYED_WORK(&rt2x00dev->link.agc_work, rt2x00link_agc);
c965c74b	489	INIT_DELAYED_WORK(&rt2x00dev->link.watchdog_work, rt2x00link_watchdog);
84e3196f ID	490	INIT_DELAYED_WORK(&rt2x00dev->link.work, rt2x00link_tuner);
84e3196f ID	491	}