2 Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com>
3 <http://rt2x00.serialmonkey.com>
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.
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.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, see <http://www.gnu.org/licenses/>.
21 Abstract: rt2x00 generic link tuning routines.
24 #include <linux/kernel.h>
25 #include <linux/module.h>
28 #include "rt2x00lib.h"
31 * When we lack RSSI information return something less then -80 to
32 * tell the driver to tune the device to maximum sensitivity.
34 #define DEFAULT_RSSI -128
36 static inline int rt2x00link_get_avg_rssi(struct ewma_rssi *ewma)
40 avg = ewma_rssi_read(ewma);
47 static int rt2x00link_antenna_get_link_rssi(struct rt2x00_dev *rt2x00dev)
49 struct link_ant *ant = &rt2x00dev->link.ant;
51 if (rt2x00dev->link.qual.rx_success)
52 return rt2x00link_get_avg_rssi(&ant->rssi_ant);
57 static int rt2x00link_antenna_get_rssi_history(struct rt2x00_dev *rt2x00dev)
59 struct link_ant *ant = &rt2x00dev->link.ant;
61 if (ant->rssi_history)
62 return ant->rssi_history;
66 static void rt2x00link_antenna_update_rssi_history(struct rt2x00_dev *rt2x00dev,
69 struct link_ant *ant = &rt2x00dev->link.ant;
70 ant->rssi_history = rssi;
73 static void rt2x00link_antenna_reset(struct rt2x00_dev *rt2x00dev)
75 ewma_rssi_init(&rt2x00dev->link.ant.rssi_ant);
78 static void rt2x00lib_antenna_diversity_sample(struct rt2x00_dev *rt2x00dev)
80 struct link_ant *ant = &rt2x00dev->link.ant;
81 struct antenna_setup new_ant;
84 int sample_current = rt2x00link_antenna_get_link_rssi(rt2x00dev);
85 int sample_other = rt2x00link_antenna_get_rssi_history(rt2x00dev);
87 memcpy(&new_ant, &ant->active, sizeof(new_ant));
90 * We are done sampling. Now we should evaluate the results.
92 ant->flags &= ~ANTENNA_MODE_SAMPLE;
95 * During the last period we have sampled the RSSI
96 * from both antennas. It now is time to determine
97 * which antenna demonstrated the best performance.
98 * When we are already on the antenna with the best
99 * performance, just create a good starting point
100 * for the history and we are done.
102 if (sample_current >= sample_other) {
103 rt2x00link_antenna_update_rssi_history(rt2x00dev,
108 other_antenna = (ant->active.rx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;
110 if (ant->flags & ANTENNA_RX_DIVERSITY)
111 new_ant.rx = other_antenna;
113 if (ant->flags & ANTENNA_TX_DIVERSITY)
114 new_ant.tx = other_antenna;
116 rt2x00lib_config_antenna(rt2x00dev, new_ant);
119 static void rt2x00lib_antenna_diversity_eval(struct rt2x00_dev *rt2x00dev)
121 struct link_ant *ant = &rt2x00dev->link.ant;
122 struct antenna_setup new_ant;
126 memcpy(&new_ant, &ant->active, sizeof(new_ant));
129 * Get current RSSI value along with the historical value,
130 * after that update the history with the current value.
132 rssi_curr = rt2x00link_antenna_get_link_rssi(rt2x00dev);
133 rssi_old = rt2x00link_antenna_get_rssi_history(rt2x00dev);
134 rt2x00link_antenna_update_rssi_history(rt2x00dev, rssi_curr);
137 * Legacy driver indicates that we should swap antenna's
138 * when the difference in RSSI is greater that 5. This
139 * also should be done when the RSSI was actually better
140 * then the previous sample.
141 * When the difference exceeds the threshold we should
142 * sample the rssi from the other antenna to make a valid
143 * comparison between the 2 antennas.
145 if (abs(rssi_curr - rssi_old) < 5)
148 ant->flags |= ANTENNA_MODE_SAMPLE;
150 if (ant->flags & ANTENNA_RX_DIVERSITY)
151 new_ant.rx = (new_ant.rx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;
153 if (ant->flags & ANTENNA_TX_DIVERSITY)
154 new_ant.tx = (new_ant.tx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;
156 rt2x00lib_config_antenna(rt2x00dev, new_ant);
159 static bool rt2x00lib_antenna_diversity(struct rt2x00_dev *rt2x00dev)
161 struct link_ant *ant = &rt2x00dev->link.ant;
164 * Determine if software diversity is enabled for
165 * either the TX or RX antenna (or both).
167 if (!(ant->flags & ANTENNA_RX_DIVERSITY) &&
168 !(ant->flags & ANTENNA_TX_DIVERSITY)) {
174 * If we have only sampled the data over the last period
175 * we should now harvest the data. Otherwise just evaluate
176 * the data. The latter should only be performed once
179 if (ant->flags & ANTENNA_MODE_SAMPLE) {
180 rt2x00lib_antenna_diversity_sample(rt2x00dev);
182 } else if (rt2x00dev->link.count & 1) {
183 rt2x00lib_antenna_diversity_eval(rt2x00dev);
190 void rt2x00link_update_stats(struct rt2x00_dev *rt2x00dev,
192 struct rxdone_entry_desc *rxdesc)
194 struct link *link = &rt2x00dev->link;
195 struct link_qual *qual = &rt2x00dev->link.qual;
196 struct link_ant *ant = &rt2x00dev->link.ant;
197 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
200 * No need to update the stats for !=STA interfaces
202 if (!rt2x00dev->intf_sta_count)
206 * Frame was received successfully since non-succesfull
207 * frames would have been dropped by the hardware.
212 * We are only interested in quality statistics from
213 * beacons which came from the BSS which we are
216 if (!ieee80211_is_beacon(hdr->frame_control) ||
217 !(rxdesc->dev_flags & RXDONE_MY_BSS))
223 ewma_rssi_add(&link->avg_rssi, -rxdesc->rssi);
226 * Update antenna RSSI
228 ewma_rssi_add(&ant->rssi_ant, -rxdesc->rssi);
231 void rt2x00link_start_tuner(struct rt2x00_dev *rt2x00dev)
233 struct link *link = &rt2x00dev->link;
236 * Link tuning should only be performed when
237 * an active sta interface exists. AP interfaces
238 * don't need link tuning and monitor mode interfaces
239 * should never have to work with link tuners.
241 if (!rt2x00dev->intf_sta_count)
245 * While scanning, link tuning is disabled. By default
246 * the most sensitive settings will be used to make sure
247 * that all beacons and probe responses will be received
250 if (test_bit(DEVICE_STATE_SCANNING, &rt2x00dev->flags))
253 rt2x00link_reset_tuner(rt2x00dev, false);
255 if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
256 ieee80211_queue_delayed_work(rt2x00dev->hw,
257 &link->work, LINK_TUNE_INTERVAL);
260 void rt2x00link_stop_tuner(struct rt2x00_dev *rt2x00dev)
262 cancel_delayed_work_sync(&rt2x00dev->link.work);
265 void rt2x00link_reset_tuner(struct rt2x00_dev *rt2x00dev, bool antenna)
267 struct link_qual *qual = &rt2x00dev->link.qual;
268 u8 vgc_level = qual->vgc_level_reg;
270 if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
274 * Reset link information.
275 * Both the currently active vgc level as well as
276 * the link tuner counter should be reset. Resetting
277 * the counter is important for devices where the
278 * device should only perform link tuning during the
279 * first minute after being enabled.
281 rt2x00dev->link.count = 0;
282 memset(qual, 0, sizeof(*qual));
283 ewma_rssi_init(&rt2x00dev->link.avg_rssi);
286 * Restore the VGC level as stored in the registers,
287 * the driver can use this to determine if the register
288 * must be updated during reset or not.
290 qual->vgc_level_reg = vgc_level;
293 * Reset the link tuner.
295 rt2x00dev->ops->lib->reset_tuner(rt2x00dev, qual);
298 rt2x00link_antenna_reset(rt2x00dev);
301 static void rt2x00link_reset_qual(struct rt2x00_dev *rt2x00dev)
303 struct link_qual *qual = &rt2x00dev->link.qual;
305 qual->rx_success = 0;
307 qual->tx_success = 0;
311 static void rt2x00link_tuner(struct work_struct *work)
313 struct rt2x00_dev *rt2x00dev =
314 container_of(work, struct rt2x00_dev, link.work.work);
315 struct link *link = &rt2x00dev->link;
316 struct link_qual *qual = &rt2x00dev->link.qual;
319 * When the radio is shutting down we should
320 * immediately cease all link tuning.
322 if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags) ||
323 test_bit(DEVICE_STATE_SCANNING, &rt2x00dev->flags))
329 rt2x00dev->ops->lib->link_stats(rt2x00dev, qual);
330 rt2x00dev->low_level_stats.dot11FCSErrorCount += qual->rx_failed;
333 * Update quality RSSI for link tuning,
334 * when we have received some frames and we managed to
335 * collect the RSSI data we could use this. Otherwise we
336 * must fallback to the default RSSI value.
338 if (!qual->rx_success)
339 qual->rssi = DEFAULT_RSSI;
341 qual->rssi = rt2x00link_get_avg_rssi(&link->avg_rssi);
344 * Check if link tuning is supported by the hardware, some hardware
345 * do not support link tuning at all, while other devices can disable
346 * the feature from the EEPROM.
348 if (rt2x00_has_cap_link_tuning(rt2x00dev))
349 rt2x00dev->ops->lib->link_tuner(rt2x00dev, qual, link->count);
352 * Send a signal to the led to update the led signal strength.
354 rt2x00leds_led_quality(rt2x00dev, qual->rssi);
357 * Evaluate antenna setup, make this the last step when
358 * rt2x00lib_antenna_diversity made changes the quality
359 * statistics will be reset.
361 if (rt2x00lib_antenna_diversity(rt2x00dev))
362 rt2x00link_reset_qual(rt2x00dev);
365 * Increase tuner counter, and reschedule the next link tuner run.
369 if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
370 ieee80211_queue_delayed_work(rt2x00dev->hw,
371 &link->work, LINK_TUNE_INTERVAL);
374 void rt2x00link_start_watchdog(struct rt2x00_dev *rt2x00dev)
376 struct link *link = &rt2x00dev->link;
378 if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags) &&
379 rt2x00dev->ops->lib->watchdog)
380 ieee80211_queue_delayed_work(rt2x00dev->hw,
381 &link->watchdog_work,
385 void rt2x00link_stop_watchdog(struct rt2x00_dev *rt2x00dev)
387 cancel_delayed_work_sync(&rt2x00dev->link.watchdog_work);
390 static void rt2x00link_watchdog(struct work_struct *work)
392 struct rt2x00_dev *rt2x00dev =
393 container_of(work, struct rt2x00_dev, link.watchdog_work.work);
394 struct link *link = &rt2x00dev->link;
397 * When the radio is shutting down we should
398 * immediately cease the watchdog monitoring.
400 if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
403 rt2x00dev->ops->lib->watchdog(rt2x00dev);
405 if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
406 ieee80211_queue_delayed_work(rt2x00dev->hw,
407 &link->watchdog_work,
411 void rt2x00link_start_agc(struct rt2x00_dev *rt2x00dev)
413 struct link *link = &rt2x00dev->link;
415 if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags) &&
416 rt2x00dev->ops->lib->gain_calibration)
417 ieee80211_queue_delayed_work(rt2x00dev->hw,
422 void rt2x00link_start_vcocal(struct rt2x00_dev *rt2x00dev)
424 struct link *link = &rt2x00dev->link;
426 if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags) &&
427 rt2x00dev->ops->lib->vco_calibration)
428 ieee80211_queue_delayed_work(rt2x00dev->hw,
433 void rt2x00link_stop_agc(struct rt2x00_dev *rt2x00dev)
435 cancel_delayed_work_sync(&rt2x00dev->link.agc_work);
438 void rt2x00link_stop_vcocal(struct rt2x00_dev *rt2x00dev)
440 cancel_delayed_work_sync(&rt2x00dev->link.vco_work);
443 static void rt2x00link_agc(struct work_struct *work)
445 struct rt2x00_dev *rt2x00dev =
446 container_of(work, struct rt2x00_dev, link.agc_work.work);
447 struct link *link = &rt2x00dev->link;
450 * When the radio is shutting down we should
451 * immediately cease the watchdog monitoring.
453 if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
456 rt2x00dev->ops->lib->gain_calibration(rt2x00dev);
458 if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
459 ieee80211_queue_delayed_work(rt2x00dev->hw,
464 static void rt2x00link_vcocal(struct work_struct *work)
466 struct rt2x00_dev *rt2x00dev =
467 container_of(work, struct rt2x00_dev, link.vco_work.work);
468 struct link *link = &rt2x00dev->link;
471 * When the radio is shutting down we should
472 * immediately cease the VCO calibration.
474 if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
477 rt2x00dev->ops->lib->vco_calibration(rt2x00dev);
479 if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
480 ieee80211_queue_delayed_work(rt2x00dev->hw,
485 void rt2x00link_register(struct rt2x00_dev *rt2x00dev)
487 INIT_DELAYED_WORK(&rt2x00dev->link.agc_work, rt2x00link_agc);
488 if (rt2x00_has_cap_vco_recalibration(rt2x00dev))
489 INIT_DELAYED_WORK(&rt2x00dev->link.vco_work, rt2x00link_vcocal);
490 INIT_DELAYED_WORK(&rt2x00dev->link.watchdog_work, rt2x00link_watchdog);
491 INIT_DELAYED_WORK(&rt2x00dev->link.work, rt2x00link_tuner);