diff options
Diffstat (limited to 'drivers/net/wireless/ralink/rt2x00/rt2x00link.c')
| -rw-r--r-- | drivers/net/wireless/ralink/rt2x00/rt2x00link.c | 428 |
1 files changed, 428 insertions, 0 deletions
diff --git a/drivers/net/wireless/ralink/rt2x00/rt2x00link.c b/drivers/net/wireless/ralink/rt2x00/rt2x00link.c new file mode 100644 index 000000000..b052c9634 --- /dev/null +++ b/drivers/net/wireless/ralink/rt2x00/rt2x00link.c @@ -0,0 +1,428 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com> + <http://rt2x00.serialmonkey.com> + + */ + +/* + 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 && !link->watchdog_disabled) + ieee80211_queue_delayed_work(rt2x00dev->hw, + &link->watchdog_work, + link->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, + link->watchdog_interval); +} + +void rt2x00link_register(struct rt2x00_dev *rt2x00dev) +{ + struct link *link = &rt2x00dev->link; + + INIT_DELAYED_WORK(&link->work, rt2x00link_tuner); + INIT_DELAYED_WORK(&link->watchdog_work, rt2x00link_watchdog); + + if (link->watchdog_interval == 0) + link->watchdog_interval = WATCHDOG_INTERVAL; +} |