[linux-block.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;
	unsigned int flags = ant->flags;

	/*
	 * 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.
	 */
	flags &= ~ANTENNA_RX_DIVERSITY;
	flags &= ~ANTENNA_TX_DIVERSITY;

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

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

	/* Update flags */
	ant->flags = flags;

	/*
	 * 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;

	/*
	 * 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 or master interface exists.
	 * Single monitor mode interfaces should never have
	 * work with link tuners.
	 */
	if (!rt2x00dev->intf_ap_count && !rt2x00dev->intf_sta_count)
		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;

	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));

	/*
	 * 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))
		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;

	/*
	 * Only perform the link tuning when Link tuning
	 * has been enabled (This could have been disabled from the EEPROM).
	 */
	if (!test_bit(CONFIG_DISABLE_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_register(struct rt2x00_dev *rt2x00dev)
{
	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))) / \
	70	(AVG_SAMPLES) ) : \
	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	{
84e3196f ID	190	struct link_ant *ant = &rt2x00dev->link.ant;
bdfa500b	191	unsigned int flags = ant->flags;
84e3196f ID	192
	193	/*
	194	* Determine if software diversity is enabled for
	195	* either the TX or RX antenna (or both).
	196	* Always perform this check since within the link
	197	* tuner interval the configuration might have changed.
	198	*/
bdfa500b ID	199	flags &= ~ANTENNA_RX_DIVERSITY;
bdfa500b ID	200	flags &= ~ANTENNA_TX_DIVERSITY;
84e3196f ID	201
84e3196f ID	202	if (rt2x00dev->default_ant.rx == ANTENNA_SW_DIVERSITY)
bdfa500b	203	flags \|= ANTENNA_RX_DIVERSITY;
84e3196f	204	if (rt2x00dev->default_ant.tx == ANTENNA_SW_DIVERSITY)
bdfa500b	205	flags \|= ANTENNA_TX_DIVERSITY;
84e3196f ID	206
	207	if (!(ant->flags & ANTENNA_RX_DIVERSITY) &&
	208	!(ant->flags & ANTENNA_TX_DIVERSITY)) {
	209	ant->flags = 0;
193df183	210	return true;
84e3196f ID	211	}
84e3196f ID	212
bdfa500b ID	213	/* Update flags */
	214	ant->flags = flags;
	215
84e3196f ID	216	/*
	217	* If we have only sampled the data over the last period
	218	* we should now harvest the data. Otherwise just evaluate
	219	* the data. The latter should only be performed once
	220	* every 2 seconds.
	221	*/
193df183	222	if (ant->flags & ANTENNA_MODE_SAMPLE) {
84e3196f	223	rt2x00lib_antenna_diversity_sample(rt2x00dev);
193df183 LE	224	return true;
193df183 LE	225	} else if (rt2x00dev->link.count & 1) {
84e3196f	226	rt2x00lib_antenna_diversity_eval(rt2x00dev);
193df183 LE	227	return true;
	228	}
	229
	230	return false;
84e3196f ID	231	}
	232
	233	void rt2x00link_update_stats(struct rt2x00_dev *rt2x00dev,
	234	struct sk_buff *skb,
	235	struct rxdone_entry_desc *rxdesc)
	236	{
5352ff65	237	struct link *link = &rt2x00dev->link;
84e3196f ID	238	struct link_qual *qual = &rt2x00dev->link.qual;
	239	struct link_ant *ant = &rt2x00dev->link.ant;
	240	struct ieee80211_hdr hdr = (struct ieee80211_hdr )skb->data;
84e3196f ID	241
	242	/*
	243	* Frame was received successfully since non-succesfull
	244	* frames would have been dropped by the hardware.
	245	*/
	246	qual->rx_success++;
	247
	248	/*
	249	* We are only interested in quality statistics from
	250	* beacons which came from the BSS which we are
	251	* associated with.
	252	*/
	253	if (!ieee80211_is_beacon(hdr->frame_control) \|\|
	254	!(rxdesc->dev_flags & RXDONE_MY_BSS))
	255	return;
	256
	257	/*
	258	* Update global RSSI
	259	*/
66679a65	260	link->avg_rssi = MOVING_AVERAGE(link->avg_rssi, rxdesc->rssi);
84e3196f ID	261
	262	/*
	263	* Update antenna RSSI
	264	*/
66679a65	265	ant->rssi_ant = MOVING_AVERAGE(ant->rssi_ant, rxdesc->rssi);
84e3196f ID	266	}
84e3196f ID	267
84e3196f ID	268	void rt2x00link_start_tuner(struct rt2x00_dev *rt2x00dev)
84e3196f ID	269	{
5352ff65	270	struct link *link = &rt2x00dev->link;
84e3196f ID	271
	272	/*
	273	* Link tuning should only be performed when
	274	* an active sta or master interface exists.
	275	* Single monitor mode interfaces should never have
	276	* work with link tuners.
	277	*/
	278	if (!rt2x00dev->intf_ap_count && !rt2x00dev->intf_sta_count)
	279	return;
	280
84e3196f ID	281	rt2x00link_reset_tuner(rt2x00dev, false);
84e3196f ID	282
66f84d65 SC	283	if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
	284	ieee80211_queue_delayed_work(rt2x00dev->hw,
	285	&link->work, LINK_TUNE_INTERVAL);
84e3196f ID	286	}
	287
	288	void rt2x00link_stop_tuner(struct rt2x00_dev *rt2x00dev)
	289	{
	290	cancel_delayed_work_sync(&rt2x00dev->link.work);
	291	}
	292
	293	void rt2x00link_reset_tuner(struct rt2x00_dev *rt2x00dev, bool antenna)
	294	{
5352ff65 ID	295	struct link_qual *qual = &rt2x00dev->link.qual;
5352ff65 ID	296
84e3196f ID	297	if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
	298	return;
	299
	300	/*
	301	* Reset link information.
	302	* Both the currently active vgc level as well as
	303	* the link tuner counter should be reset. Resetting
	304	* the counter is important for devices where the
	305	* device should only perform link tuning during the
	306	* first minute after being enabled.
	307	*/
	308	rt2x00dev->link.count = 0;
5352ff65	309	memset(qual, 0, sizeof(*qual));
84e3196f ID	310
	311	/*
	312	* Reset the link tuner.
	313	*/
5352ff65	314	rt2x00dev->ops->lib->reset_tuner(rt2x00dev, qual);
84e3196f ID	315
	316	if (antenna)
	317	rt2x00link_antenna_reset(rt2x00dev);
	318	}
	319
a57e2e84	320	static void rt2x00link_reset_qual(struct rt2x00_dev *rt2x00dev)
64abd803 ID	321	{
	322	struct link_qual *qual = &rt2x00dev->link.qual;
	323
	324	qual->rx_success = 0;
	325	qual->rx_failed = 0;
	326	qual->tx_success = 0;
	327	qual->tx_failed = 0;
	328	}
	329
84e3196f ID	330	static void rt2x00link_tuner(struct work_struct *work)
	331	{
	332	struct rt2x00_dev *rt2x00dev =
	333	container_of(work, struct rt2x00_dev, link.work.work);
5352ff65	334	struct link *link = &rt2x00dev->link;
84e3196f ID	335	struct link_qual *qual = &rt2x00dev->link.qual;
	336
	337	/*
	338	* When the radio is shutting down we should
	339	* immediately cease all link tuning.
	340	*/
	341	if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
	342	return;
	343
	344	/*
	345	* Update statistics.
	346	*/
	347	rt2x00dev->ops->lib->link_stats(rt2x00dev, qual);
	348	rt2x00dev->low_level_stats.dot11FCSErrorCount += qual->rx_failed;
	349
5352ff65 ID	350	/*
	351	* Update quality RSSI for link tuning,
	352	* when we have received some frames and we managed to
	353	* collect the RSSI data we could use this. Otherwise we
	354	* must fallback to the default RSSI value.
	355	*/
66679a65	356	if (!link->avg_rssi.avg \|\| !qual->rx_success)
5352ff65 ID	357	qual->rssi = DEFAULT_RSSI;
5352ff65 ID	358	else
66679a65	359	qual->rssi = link->avg_rssi.avg;
5352ff65	360
84e3196f ID	361	/*
	362	* Only perform the link tuning when Link tuning
	363	* has been enabled (This could have been disabled from the EEPROM).
	364	*/
	365	if (!test_bit(CONFIG_DISABLE_LINK_TUNING, &rt2x00dev->flags))
5352ff65	366	rt2x00dev->ops->lib->link_tuner(rt2x00dev, qual, link->count);
84e3196f	367
84e3196f ID	368	/*
	369	* Send a signal to the led to update the led signal strength.
	370	*/
66679a65	371	rt2x00leds_led_quality(rt2x00dev, qual->rssi);
84e3196f ID	372
84e3196f ID	373	/*
193df183 LE	374	* Evaluate antenna setup, make this the last step when
	375	* rt2x00lib_antenna_diversity made changes the quality
	376	* statistics will be reset.
64abd803	377	*/
193df183 LE	378	if (rt2x00lib_antenna_diversity(rt2x00dev))
193df183 LE	379	rt2x00link_reset_qual(rt2x00dev);
64abd803	380
84e3196f ID	381	/*
	382	* Increase tuner counter, and reschedule the next link tuner run.
	383	*/
5352ff65	384	link->count++;
66f84d65 SC	385
	386	if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
	387	ieee80211_queue_delayed_work(rt2x00dev->hw,
	388	&link->work, LINK_TUNE_INTERVAL);
84e3196f ID	389	}
	390
	391	void rt2x00link_register(struct rt2x00_dev *rt2x00dev)
	392	{
	393	INIT_DELAYED_WORK(&rt2x00dev->link.work, rt2x00link_tuner);
	394	}