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

/*
	Copyright (C) 2004 - 2009 rt2x00 SourceForge Project
	<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

/*
 * When no TX/RX percentage could be calculated due to lack of
 * frames on the air, we fallback to a percentage of 50%.
 * This will assure we will get at least get some decent value
 * when the link tuner starts.
 * The value will be dropped and overwritten with the correct (measured)
 * value anyway during the first run of the link tuner.
 */
#define DEFAULT_PERCENTAGE	50

/*
 * Small helper 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.
 */
#define MOVING_AVERAGE(__avg, __val, __samples) \
	( (((__avg) * ((__samples) - 1)) + (__val)) / (__samples) )

/*
 * Small helper macro for percentage calculation
 * This is a very simple macro with the only catch that it will
 * produce a default value in case no total value was provided.
 */
#define PERCENTAGE(__value, __total) \
	( (__total) ? (((__value) * 100) / (__total)) : (DEFAULT_PERCENTAGE) )

/*
 * For calculating the Signal quality we have determined
 * the total number of success and failed RX and TX frames.
 * With the addition of the average RSSI value we can determine
 * the link quality using the following algorithm:
 *
 *         rssi_percentage = (avg_rssi * 100) / rssi_offset
 *         rx_percentage = (rx_success * 100) / rx_total
 *         tx_percentage = (tx_success * 100) / tx_total
 *         avg_signal = ((WEIGHT_RSSI * avg_rssi) +
 *                       (WEIGHT_TX * tx_percentage) +
 *                       (WEIGHT_RX * rx_percentage)) / 100
 *
 * This value should then be checked to not be greater then 100.
 * This means the values of WEIGHT_RSSI, WEIGHT_RX, WEIGHT_TX must
 * sum up to 100 as well.
 */
#define WEIGHT_RSSI	20
#define WEIGHT_RX	40
#define WEIGHT_TX	40

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

	if (ant->rssi_ant && rt2x00dev->link.qual.rx_success)
		return ant->rssi_ant;
	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 = 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;
	int avg_rssi = rxdesc->rssi;
	int ant_rssi = rxdesc->rssi;

	/*
	 * 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
	 */
	if (link->avg_rssi)
		avg_rssi = MOVING_AVERAGE(link->avg_rssi, rxdesc->rssi, 8);
	link->avg_rssi = avg_rssi;

	/*
	 * Update antenna RSSI
	 */
	if (ant->rssi_ant)
		ant_rssi = MOVING_AVERAGE(ant->rssi_ant, rxdesc->rssi, 8);
	ant->rssi_ant = ant_rssi;
}

static void rt2x00link_precalculate_signal(struct rt2x00_dev *rt2x00dev)
{
	struct link *link = &rt2x00dev->link;
	struct link_qual *qual = &rt2x00dev->link.qual;

	link->rx_percentage =
	    PERCENTAGE(qual->rx_success, qual->rx_failed + qual->rx_success);
	link->tx_percentage =
	    PERCENTAGE(qual->tx_success, qual->tx_failed + qual->tx_success);
}

int rt2x00link_calculate_signal(struct rt2x00_dev *rt2x00dev, int rssi)
{
	struct link *link = &rt2x00dev->link;
	int rssi_percentage = 0;
	int signal;

	/*
	 * We need a positive value for the RSSI.
	 */
	if (rssi < 0)
		rssi += rt2x00dev->rssi_offset;

	/*
	 * Calculate the different percentages,
	 * which will be used for the signal.
	 */
	rssi_percentage = PERCENTAGE(rssi, rt2x00dev->rssi_offset);

	/*
	 * Add the individual percentages and use the WEIGHT
	 * defines to calculate the current link signal.
	 */
	signal = ((WEIGHT_RSSI * rssi_percentage) +
		  (WEIGHT_TX * link->tx_percentage) +
		  (WEIGHT_RX * link->rx_percentage)) / 100;

	return max_t(int, signal, 100);
}

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;

	link->rx_percentage = DEFAULT_PERCENTAGE;
	link->tx_percentage = DEFAULT_PERCENTAGE;

	rt2x00link_reset_tuner(rt2x00dev, false);

	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 || !qual->rx_success)
		qual->rssi = DEFAULT_RSSI;
	else
		qual->rssi = link->avg_rssi;

	/*
	 * 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);

	/*
	 * Precalculate a portion of the link signal which is
	 * in based on the tx/rx success/failure counters.
	 */
	rt2x00link_precalculate_signal(rt2x00dev);

	/*
	 * Send a signal to the led to update the led signal strength.
	 */
	rt2x00leds_led_quality(rt2x00dev, link->avg_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++;
	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	/*
4e54c711	2	Copyright (C) 2004 - 2009 rt2x00 SourceForge Project
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
	38	/*
	39	* When no TX/RX percentage could be calculated due to lack of
	40	* frames on the air, we fallback to a percentage of 50%.
	41	* This will assure we will get at least get some decent value
	42	* when the link tuner starts.
	43	* The value will be dropped and overwritten with the correct (measured)
	44	* value anyway during the first run of the link tuner.
	45	*/
	46	#define DEFAULT_PERCENTAGE 50
	47
	48	/*
	49	* Small helper macro to work with moving/walking averages.
	50	* When adding a value to the average value the following calculation
	51	* is needed:
	52	*
	53	* avg_rssi = ((avg_rssi * 7) + rssi) / 8;
	54	*
	55	* The advantage of this approach is that we only need 1 variable
	56	* to store the average in (No need for a count and a total).
	57	* But more importantly, normal average values will over time
	58	* move less and less towards newly added values this results
	59	* that with link tuning, the device can have a very good RSSI
	60	* for a few minutes but when the device is moved away from the AP
	61	* the average will not decrease fast enough to compensate.
	62	* The walking average compensates this and will move towards
	63	* the new values correctly allowing a effective link tuning.
	64	*/
	65	#define MOVING_AVERAGE(__avg, __val, __samples) \
	66	( (((__avg) * ((__samples) - 1)) + (__val)) / (__samples) )
	67
	68	/*
	69	* Small helper macro for percentage calculation
	70	* This is a very simple macro with the only catch that it will
	71	* produce a default value in case no total value was provided.
	72	*/
	73	#define PERCENTAGE(__value, __total) \
	74	( (__total) ? (((__value) * 100) / (__total)) : (DEFAULT_PERCENTAGE) )
	75
	76	/*
	77	* For calculating the Signal quality we have determined
	78	* the total number of success and failed RX and TX frames.
	79	* With the addition of the average RSSI value we can determine
	80	* the link quality using the following algorithm:
	81	*
	82	* rssi_percentage = (avg_rssi * 100) / rssi_offset
	83	* rx_percentage = (rx_success * 100) / rx_total
	84	* tx_percentage = (tx_success * 100) / tx_total
	85	* avg_signal = ((WEIGHT_RSSI * avg_rssi) +
	86	* (WEIGHT_TX * tx_percentage) +
	87	* (WEIGHT_RX * rx_percentage)) / 100
	88	*
	89	* This value should then be checked to not be greater then 100.
	90	* This means the values of WEIGHT_RSSI, WEIGHT_RX, WEIGHT_TX must
	91	* sum up to 100 as well.
	92	*/
	93	#define WEIGHT_RSSI 20
	94	#define WEIGHT_RX 40
	95	#define WEIGHT_TX 40
96
84e3196f ID	97	static int rt2x00link_antenna_get_link_rssi(struct rt2x00_dev *rt2x00dev)
	98	{
	99	struct link_ant *ant = &rt2x00dev->link.ant;
	100
	101	if (ant->rssi_ant && rt2x00dev->link.qual.rx_success)
	102	return ant->rssi_ant;
	103	return DEFAULT_RSSI;
	104	}
	105
193df183	106	static int rt2x00link_antenna_get_rssi_history(struct rt2x00_dev *rt2x00dev)
84e3196f ID	107	{
	108	struct link_ant *ant = &rt2x00dev->link.ant;
	109
193df183 LE	110	if (ant->rssi_history)
193df183 LE	111	return ant->rssi_history;
84e3196f ID	112	return DEFAULT_RSSI;
84e3196f ID	113	}
84e3196f ID	114
84e3196f ID	115	static void rt2x00link_antenna_update_rssi_history(struct rt2x00_dev *rt2x00dev,
84e3196f ID	116	int rssi)
	117	{
	118	struct link_ant *ant = &rt2x00dev->link.ant;
193df183	119	ant->rssi_history = rssi;
84e3196f	120	}
84e3196f ID	121
	122	static void rt2x00link_antenna_reset(struct rt2x00_dev *rt2x00dev)
	123	{
	124	rt2x00dev->link.ant.rssi_ant = 0;
	125	}
	126
	127	static void rt2x00lib_antenna_diversity_sample(struct rt2x00_dev *rt2x00dev)
	128	{
	129	struct link_ant *ant = &rt2x00dev->link.ant;
	130	struct antenna_setup new_ant;
193df183 LE	131	int other_antenna;
	132
	133	int sample_current = rt2x00link_antenna_get_link_rssi(rt2x00dev);
	134	int sample_other = rt2x00link_antenna_get_rssi_history(rt2x00dev);
84e3196f ID	135
	136	memcpy(&new_ant, &ant->active, sizeof(new_ant));
	137
	138	/*
	139	* We are done sampling. Now we should evaluate the results.
	140	*/
	141	ant->flags &= ~ANTENNA_MODE_SAMPLE;
	142
	143	/*
	144	* During the last period we have sampled the RSSI
49513481	145	* from both antennas. It now is time to determine
84e3196f ID	146	* which antenna demonstrated the best performance.
84e3196f ID	147	* When we are already on the antenna with the best
193df183 LE	148	* performance, just create a good starting point
193df183 LE	149	* for the history and we are done.
84e3196f	150	*/
193df183 LE	151	if (sample_current >= sample_other) {
	152	rt2x00link_antenna_update_rssi_history(rt2x00dev,
	153	sample_current);
84e3196f	154	return;
193df183 LE	155	}
	156
	157	other_antenna = (ant->active.rx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;
84e3196f ID	158
84e3196f ID	159	if (ant->flags & ANTENNA_RX_DIVERSITY)
193df183	160	new_ant.rx = other_antenna;
84e3196f ID	161
84e3196f ID	162	if (ant->flags & ANTENNA_TX_DIVERSITY)
193df183	163	new_ant.tx = other_antenna;
84e3196f	164
eb87eaac	165	rt2x00lib_config_antenna(rt2x00dev, new_ant);
84e3196f ID	166	}
	167
	168	static void rt2x00lib_antenna_diversity_eval(struct rt2x00_dev *rt2x00dev)
	169	{
	170	struct link_ant *ant = &rt2x00dev->link.ant;
	171	struct antenna_setup new_ant;
	172	int rssi_curr;
	173	int rssi_old;
	174
	175	memcpy(&new_ant, &ant->active, sizeof(new_ant));
	176
	177	/*
	178	* Get current RSSI value along with the historical value,
	179	* after that update the history with the current value.
	180	*/
	181	rssi_curr = rt2x00link_antenna_get_link_rssi(rt2x00dev);
193df183 LE	182	rssi_old = rt2x00link_antenna_get_rssi_history(rt2x00dev);
193df183 LE	183	rt2x00link_antenna_update_rssi_history(rt2x00dev, rssi_curr);
84e3196f ID	184
	185	/*
	186	* Legacy driver indicates that we should swap antenna's
	187	* when the difference in RSSI is greater that 5. This
	188	* also should be done when the RSSI was actually better
	189	* then the previous sample.
	190	* When the difference exceeds the threshold we should
	191	* sample the rssi from the other antenna to make a valid
	192	* comparison between the 2 antennas.
	193	*/
	194	if (abs(rssi_curr - rssi_old) < 5)
	195	return;
	196
	197	ant->flags \|= ANTENNA_MODE_SAMPLE;
	198
	199	if (ant->flags & ANTENNA_RX_DIVERSITY)
	200	new_ant.rx = (new_ant.rx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;
	201
	202	if (ant->flags & ANTENNA_TX_DIVERSITY)
	203	new_ant.tx = (new_ant.tx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;
	204
eb87eaac	205	rt2x00lib_config_antenna(rt2x00dev, new_ant);
84e3196f ID	206	}
84e3196f ID	207
193df183	208	static bool rt2x00lib_antenna_diversity(struct rt2x00_dev *rt2x00dev)
84e3196f ID	209	{
84e3196f ID	210	struct link_ant *ant = &rt2x00dev->link.ant;
bdfa500b	211	unsigned int flags = ant->flags;
84e3196f ID	212
	213	/*
	214	* Determine if software diversity is enabled for
	215	* either the TX or RX antenna (or both).
	216	* Always perform this check since within the link
	217	* tuner interval the configuration might have changed.
	218	*/
bdfa500b ID	219	flags &= ~ANTENNA_RX_DIVERSITY;
bdfa500b ID	220	flags &= ~ANTENNA_TX_DIVERSITY;
84e3196f ID	221
84e3196f ID	222	if (rt2x00dev->default_ant.rx == ANTENNA_SW_DIVERSITY)
bdfa500b	223	flags \|= ANTENNA_RX_DIVERSITY;
84e3196f	224	if (rt2x00dev->default_ant.tx == ANTENNA_SW_DIVERSITY)
bdfa500b	225	flags \|= ANTENNA_TX_DIVERSITY;
84e3196f ID	226
	227	if (!(ant->flags & ANTENNA_RX_DIVERSITY) &&
	228	!(ant->flags & ANTENNA_TX_DIVERSITY)) {
	229	ant->flags = 0;
193df183	230	return true;
84e3196f ID	231	}
84e3196f ID	232
bdfa500b ID	233	/* Update flags */
	234	ant->flags = flags;
	235
84e3196f ID	236	/*
	237	* If we have only sampled the data over the last period
	238	* we should now harvest the data. Otherwise just evaluate
	239	* the data. The latter should only be performed once
	240	* every 2 seconds.
	241	*/
193df183	242	if (ant->flags & ANTENNA_MODE_SAMPLE) {
84e3196f	243	rt2x00lib_antenna_diversity_sample(rt2x00dev);
193df183 LE	244	return true;
193df183 LE	245	} else if (rt2x00dev->link.count & 1) {
84e3196f	246	rt2x00lib_antenna_diversity_eval(rt2x00dev);
193df183 LE	247	return true;
	248	}
	249
	250	return false;
84e3196f ID	251	}
	252
	253	void rt2x00link_update_stats(struct rt2x00_dev *rt2x00dev,
	254	struct sk_buff *skb,
	255	struct rxdone_entry_desc *rxdesc)
	256	{
5352ff65	257	struct link *link = &rt2x00dev->link;
84e3196f ID	258	struct link_qual *qual = &rt2x00dev->link.qual;
	259	struct link_ant *ant = &rt2x00dev->link.ant;
	260	struct ieee80211_hdr hdr = (struct ieee80211_hdr )skb->data;
	261	int avg_rssi = rxdesc->rssi;
	262	int ant_rssi = rxdesc->rssi;
	263
	264	/*
	265	* Frame was received successfully since non-succesfull
	266	* frames would have been dropped by the hardware.
	267	*/
	268	qual->rx_success++;
	269
	270	/*
	271	* We are only interested in quality statistics from
	272	* beacons which came from the BSS which we are
	273	* associated with.
	274	*/
	275	if (!ieee80211_is_beacon(hdr->frame_control) \|\|
	276	!(rxdesc->dev_flags & RXDONE_MY_BSS))
	277	return;
	278
	279	/*
	280	* Update global RSSI
	281	*/
5352ff65 ID	282	if (link->avg_rssi)
	283	avg_rssi = MOVING_AVERAGE(link->avg_rssi, rxdesc->rssi, 8);
	284	link->avg_rssi = avg_rssi;
84e3196f ID	285
	286	/*
	287	* Update antenna RSSI
	288	*/
	289	if (ant->rssi_ant)
	290	ant_rssi = MOVING_AVERAGE(ant->rssi_ant, rxdesc->rssi, 8);
	291	ant->rssi_ant = ant_rssi;
	292	}
	293
	294	static void rt2x00link_precalculate_signal(struct rt2x00_dev *rt2x00dev)
	295	{
5352ff65	296	struct link *link = &rt2x00dev->link;
84e3196f ID	297	struct link_qual *qual = &rt2x00dev->link.qual;
84e3196f ID	298
5352ff65 ID	299	link->rx_percentage =
	300	PERCENTAGE(qual->rx_success, qual->rx_failed + qual->rx_success);
	301	link->tx_percentage =
	302	PERCENTAGE(qual->tx_success, qual->tx_failed + qual->tx_success);
84e3196f ID	303	}
	304
	305	int rt2x00link_calculate_signal(struct rt2x00_dev *rt2x00dev, int rssi)
	306	{
5352ff65	307	struct link *link = &rt2x00dev->link;
84e3196f ID	308	int rssi_percentage = 0;
	309	int signal;
	310
	311	/*
	312	* We need a positive value for the RSSI.
	313	*/
	314	if (rssi < 0)
	315	rssi += rt2x00dev->rssi_offset;
	316
	317	/*
	318	* Calculate the different percentages,
	319	* which will be used for the signal.
	320	*/
5352ff65	321	rssi_percentage = PERCENTAGE(rssi, rt2x00dev->rssi_offset);
84e3196f ID	322
	323	/*
	324	* Add the individual percentages and use the WEIGHT
	325	* defines to calculate the current link signal.
	326	*/
	327	signal = ((WEIGHT_RSSI * rssi_percentage) +
5352ff65 ID	328	(WEIGHT_TX * link->tx_percentage) +
5352ff65 ID	329	(WEIGHT_RX * link->rx_percentage)) / 100;
84e3196f ID	330
	331	return max_t(int, signal, 100);
	332	}
	333
	334	void rt2x00link_start_tuner(struct rt2x00_dev *rt2x00dev)
	335	{
5352ff65	336	struct link *link = &rt2x00dev->link;
84e3196f ID	337
	338	/*
	339	* Link tuning should only be performed when
	340	* an active sta or master interface exists.
	341	* Single monitor mode interfaces should never have
	342	* work with link tuners.
	343	*/
	344	if (!rt2x00dev->intf_ap_count && !rt2x00dev->intf_sta_count)
	345	return;
	346
5352ff65 ID	347	link->rx_percentage = DEFAULT_PERCENTAGE;
5352ff65 ID	348	link->tx_percentage = DEFAULT_PERCENTAGE;
84e3196f ID	349
	350	rt2x00link_reset_tuner(rt2x00dev, false);
	351
42935eca LR	352	ieee80211_queue_delayed_work(rt2x00dev->hw,
42935eca LR	353	&link->work, LINK_TUNE_INTERVAL);
84e3196f ID	354	}
	355
	356	void rt2x00link_stop_tuner(struct rt2x00_dev *rt2x00dev)
	357	{
	358	cancel_delayed_work_sync(&rt2x00dev->link.work);
	359	}
	360
	361	void rt2x00link_reset_tuner(struct rt2x00_dev *rt2x00dev, bool antenna)
	362	{
5352ff65 ID	363	struct link_qual *qual = &rt2x00dev->link.qual;
5352ff65 ID	364
84e3196f ID	365	if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
	366	return;
	367
	368	/*
	369	* Reset link information.
	370	* Both the currently active vgc level as well as
	371	* the link tuner counter should be reset. Resetting
	372	* the counter is important for devices where the
	373	* device should only perform link tuning during the
	374	* first minute after being enabled.
	375	*/
	376	rt2x00dev->link.count = 0;
5352ff65	377	memset(qual, 0, sizeof(*qual));
84e3196f ID	378
	379	/*
	380	* Reset the link tuner.
	381	*/
5352ff65	382	rt2x00dev->ops->lib->reset_tuner(rt2x00dev, qual);
84e3196f ID	383
	384	if (antenna)
	385	rt2x00link_antenna_reset(rt2x00dev);
	386	}
	387
a57e2e84	388	static void rt2x00link_reset_qual(struct rt2x00_dev *rt2x00dev)
64abd803 ID	389	{
	390	struct link_qual *qual = &rt2x00dev->link.qual;
	391
	392	qual->rx_success = 0;
	393	qual->rx_failed = 0;
	394	qual->tx_success = 0;
	395	qual->tx_failed = 0;
	396	}
	397
84e3196f ID	398	static void rt2x00link_tuner(struct work_struct *work)
	399	{
	400	struct rt2x00_dev *rt2x00dev =
	401	container_of(work, struct rt2x00_dev, link.work.work);
5352ff65	402	struct link *link = &rt2x00dev->link;
84e3196f ID	403	struct link_qual *qual = &rt2x00dev->link.qual;
	404
	405	/*
	406	* When the radio is shutting down we should
	407	* immediately cease all link tuning.
	408	*/
	409	if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
	410	return;
	411
	412	/*
	413	* Update statistics.
	414	*/
	415	rt2x00dev->ops->lib->link_stats(rt2x00dev, qual);
	416	rt2x00dev->low_level_stats.dot11FCSErrorCount += qual->rx_failed;
	417
5352ff65 ID	418	/*
	419	* Update quality RSSI for link tuning,
	420	* when we have received some frames and we managed to
	421	* collect the RSSI data we could use this. Otherwise we
	422	* must fallback to the default RSSI value.
	423	*/
	424	if (!link->avg_rssi \|\| !qual->rx_success)
	425	qual->rssi = DEFAULT_RSSI;
	426	else
	427	qual->rssi = link->avg_rssi;
	428
84e3196f ID	429	/*
	430	* Only perform the link tuning when Link tuning
	431	* has been enabled (This could have been disabled from the EEPROM).
	432	*/
	433	if (!test_bit(CONFIG_DISABLE_LINK_TUNING, &rt2x00dev->flags))
5352ff65	434	rt2x00dev->ops->lib->link_tuner(rt2x00dev, qual, link->count);
84e3196f ID	435
	436	/*
	437	* Precalculate a portion of the link signal which is
	438	* in based on the tx/rx success/failure counters.
	439	*/
	440	rt2x00link_precalculate_signal(rt2x00dev);
	441
	442	/*
	443	* Send a signal to the led to update the led signal strength.
	444	*/
5352ff65	445	rt2x00leds_led_quality(rt2x00dev, link->avg_rssi);
84e3196f ID	446
84e3196f ID	447	/*
193df183 LE	448	* Evaluate antenna setup, make this the last step when
	449	* rt2x00lib_antenna_diversity made changes the quality
	450	* statistics will be reset.
64abd803	451	*/
193df183 LE	452	if (rt2x00lib_antenna_diversity(rt2x00dev))
193df183 LE	453	rt2x00link_reset_qual(rt2x00dev);
64abd803	454
84e3196f ID	455	/*
	456	* Increase tuner counter, and reschedule the next link tuner run.
	457	*/
5352ff65	458	link->count++;
42935eca LR	459	ieee80211_queue_delayed_work(rt2x00dev->hw,
42935eca LR	460	&link->work, LINK_TUNE_INTERVAL);
84e3196f ID	461	}
	462
	463	void rt2x00link_register(struct rt2x00_dev *rt2x00dev)
	464	{
	465	INIT_DELAYED_WORK(&rt2x00dev->link.work, rt2x00link_tuner);
	466	}