ubuntu-linux-kernel/drivers/net/wireless/ralink/rt2x00/rt2x00link.c

435 lines
12 KiB
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, see <http://www.gnu.org/licenses/>.
*/
/*
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
static inline int rt2x00link_get_avg_rssi(struct ewma_rssi *ewma)
{
unsigned long avg;
avg = ewma_rssi_read(ewma);
if (avg)
return -avg;
return DEFAULT_RSSI;
}
static int rt2x00link_antenna_get_link_rssi(struct rt2x00_dev *rt2x00dev)
{
struct link_ant *ant = &rt2x00dev->link.ant;
if (rt2x00dev->link.qual.rx_success)
return rt2x00link_get_avg_rssi(&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)
{
ewma_rssi_init(&rt2x00dev->link.ant.rssi_ant);
}
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).
*/
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
*/
ewma_rssi_add(&link->avg_rssi, -rxdesc->rssi);
/*
* Update antenna RSSI
*/
ewma_rssi_add(&ant->rssi_ant, -rxdesc->rssi);
}
void rt2x00link_start_tuner(struct rt2x00_dev *rt2x00dev)
{
struct link *link = &rt2x00dev->link;
/*
* Single monitor mode interfaces should never have
* work with link tuners.
*/
if (!rt2x00dev->intf_ap_count && !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 received
* 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));
ewma_rssi_init(&rt2x00dev->link.avg_rssi);
/*
* 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_sta(struct rt2x00_dev *rt2x00dev, struct link *link)
{
struct link_qual *qual = &rt2x00dev->link.qual;
/*
* 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 (!qual->rx_success)
qual->rssi = DEFAULT_RSSI;
else
qual->rssi = rt2x00link_get_avg_rssi(&link->avg_rssi);
/*
* 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 (rt2x00_has_cap_link_tuning(rt2x00dev))
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);
}
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;
/*
* 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;
/* Do not race with rt2x00mac_config(). */
mutex_lock(&rt2x00dev->conf_mutex);
if (rt2x00dev->intf_sta_count)
rt2x00link_tuner_sta(rt2x00dev, link);
if (rt2x00dev->ops->lib->gain_calibration &&
(link->count % (AGC_SECONDS / LINK_TUNE_SECONDS)) == 0)
rt2x00dev->ops->lib->gain_calibration(rt2x00dev);
if (rt2x00dev->ops->lib->vco_calibration &&
rt2x00_has_cap_vco_recalibration(rt2x00dev) &&
(link->count % (VCO_SECONDS / LINK_TUNE_SECONDS)) == 0)
rt2x00dev->ops->lib->vco_calibration(rt2x00dev);
mutex_unlock(&rt2x00dev->conf_mutex);
/*
* 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_register(struct rt2x00_dev *rt2x00dev)
{
INIT_DELAYED_WORK(&rt2x00dev->link.watchdog_work, rt2x00link_watchdog);
INIT_DELAYED_WORK(&rt2x00dev->link.work, rt2x00link_tuner);
}