--- /dev/null
+/*
+ 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
+
+/* Constants for EWMA calculations. */
+#define RT2X00_EWMA_FACTOR 1024
+#define RT2X00_EWMA_WEIGHT 8
+
+static inline int rt2x00link_get_avg_rssi(struct ewma *ewma)
+{
+ unsigned long avg;
+
+ avg = ewma_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_init(&rt2x00dev->link.ant.rssi_ant, RT2X00_EWMA_FACTOR,
+ RT2X00_EWMA_WEIGHT);
+}
+
+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_add(&link->avg_rssi, -rxdesc->rssi);
+
+ /*
+ * Update antenna RSSI
+ */
+ ewma_add(&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 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_init(&rt2x00dev->link.avg_rssi, RT2X00_EWMA_FACTOR,
+ RT2X00_EWMA_WEIGHT);
+
+ /*
+ * 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 (!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);
+
+ /*
+ * 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_start_vcocal(struct rt2x00_dev *rt2x00dev)
+{
+ struct link *link = &rt2x00dev->link;
+
+ if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags) &&
+ rt2x00dev->ops->lib->vco_calibration)
+ ieee80211_queue_delayed_work(rt2x00dev->hw,
+ &link->vco_work,
+ VCO_INTERVAL);
+}
+
+void rt2x00link_stop_agc(struct rt2x00_dev *rt2x00dev)
+{
+ cancel_delayed_work_sync(&rt2x00dev->link.agc_work);
+}
+
+void rt2x00link_stop_vcocal(struct rt2x00_dev *rt2x00dev)
+{
+ cancel_delayed_work_sync(&rt2x00dev->link.vco_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);
+}
+
+static void rt2x00link_vcocal(struct work_struct *work)
+{
+ struct rt2x00_dev *rt2x00dev =
+ container_of(work, struct rt2x00_dev, link.vco_work.work);
+ struct link *link = &rt2x00dev->link;
+
+ /*
+ * When the radio is shutting down we should
+ * immediately cease the VCO calibration.
+ */
+ if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
+ return;
+
+ rt2x00dev->ops->lib->vco_calibration(rt2x00dev);
+
+ if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
+ ieee80211_queue_delayed_work(rt2x00dev->hw,
+ &link->vco_work,
+ VCO_INTERVAL);
+}
+
+void rt2x00link_register(struct rt2x00_dev *rt2x00dev)
+{
+ INIT_DELAYED_WORK(&rt2x00dev->link.agc_work, rt2x00link_agc);
+ if (rt2x00_has_cap_vco_recalibration(rt2x00dev))
+ INIT_DELAYED_WORK(&rt2x00dev->link.vco_work, rt2x00link_vcocal);
+ INIT_DELAYED_WORK(&rt2x00dev->link.watchdog_work, rt2x00link_watchdog);
+ INIT_DELAYED_WORK(&rt2x00dev->link.work, rt2x00link_tuner);
+}
Code Review / kvmfornfv.git / blobdiff