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, write to the
17 Free Software Foundation, Inc.,
18 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
23 Abstract: rt2x00 generic link tuning routines.
26 #include <linux/kernel.h>
27 #include <linux/module.h>
30 #include "rt2x00lib.h"
33 * When we lack RSSI information return something less then -80 to
34 * tell the driver to tune the device to maximum sensitivity.
36 #define DEFAULT_RSSI -128
38 /* Constants for EWMA calculations. */
39 #define RT2X00_EWMA_FACTOR 1024
40 #define RT2X00_EWMA_WEIGHT 8
42 static inline int rt2x00link_get_avg_rssi(struct ewma *ewma)
46 avg = ewma_read(ewma);
53 static int rt2x00link_antenna_get_link_rssi(struct rt2x00_dev *rt2x00dev)
55 struct link_ant *ant = &rt2x00dev->link.ant;
57 if (rt2x00dev->link.qual.rx_success)
58 return rt2x00link_get_avg_rssi(&ant->rssi_ant);
63 static int rt2x00link_antenna_get_rssi_history(struct rt2x00_dev *rt2x00dev)
65 struct link_ant *ant = &rt2x00dev->link.ant;
67 if (ant->rssi_history)
68 return ant->rssi_history;
72 static void rt2x00link_antenna_update_rssi_history(struct rt2x00_dev *rt2x00dev,
75 struct link_ant *ant = &rt2x00dev->link.ant;
76 ant->rssi_history = rssi;
79 static void rt2x00link_antenna_reset(struct rt2x00_dev *rt2x00dev)
81 ewma_init(&rt2x00dev->link.ant.rssi_ant, RT2X00_EWMA_FACTOR,
85 static void rt2x00lib_antenna_diversity_sample(struct rt2x00_dev *rt2x00dev)
87 struct link_ant *ant = &rt2x00dev->link.ant;
88 struct antenna_setup new_ant;
91 int sample_current = rt2x00link_antenna_get_link_rssi(rt2x00dev);
92 int sample_other = rt2x00link_antenna_get_rssi_history(rt2x00dev);
94 memcpy(&new_ant, &ant->active, sizeof(new_ant));
97 * We are done sampling. Now we should evaluate the results.
99 ant->flags &= ~ANTENNA_MODE_SAMPLE;
102 * During the last period we have sampled the RSSI
103 * from both antennas. It now is time to determine
104 * which antenna demonstrated the best performance.
105 * When we are already on the antenna with the best
106 * performance, just create a good starting point
107 * for the history and we are done.
109 if (sample_current >= sample_other) {
110 rt2x00link_antenna_update_rssi_history(rt2x00dev,
115 other_antenna = (ant->active.rx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;
117 if (ant->flags & ANTENNA_RX_DIVERSITY)
118 new_ant.rx = other_antenna;
120 if (ant->flags & ANTENNA_TX_DIVERSITY)
121 new_ant.tx = other_antenna;
123 rt2x00lib_config_antenna(rt2x00dev, new_ant);
126 static void rt2x00lib_antenna_diversity_eval(struct rt2x00_dev *rt2x00dev)
128 struct link_ant *ant = &rt2x00dev->link.ant;
129 struct antenna_setup new_ant;
133 memcpy(&new_ant, &ant->active, sizeof(new_ant));
136 * Get current RSSI value along with the historical value,
137 * after that update the history with the current value.
139 rssi_curr = rt2x00link_antenna_get_link_rssi(rt2x00dev);
140 rssi_old = rt2x00link_antenna_get_rssi_history(rt2x00dev);
141 rt2x00link_antenna_update_rssi_history(rt2x00dev, rssi_curr);
144 * Legacy driver indicates that we should swap antenna's
145 * when the difference in RSSI is greater that 5. This
146 * also should be done when the RSSI was actually better
147 * then the previous sample.
148 * When the difference exceeds the threshold we should
149 * sample the rssi from the other antenna to make a valid
150 * comparison between the 2 antennas.
152 if (abs(rssi_curr - rssi_old) < 5)
155 ant->flags |= ANTENNA_MODE_SAMPLE;
157 if (ant->flags & ANTENNA_RX_DIVERSITY)
158 new_ant.rx = (new_ant.rx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;
160 if (ant->flags & ANTENNA_TX_DIVERSITY)
161 new_ant.tx = (new_ant.tx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A;
163 rt2x00lib_config_antenna(rt2x00dev, new_ant);
166 static bool rt2x00lib_antenna_diversity(struct rt2x00_dev *rt2x00dev)
168 struct link_ant *ant = &rt2x00dev->link.ant;
171 * Determine if software diversity is enabled for
172 * either the TX or RX antenna (or both).
174 if (!(ant->flags & ANTENNA_RX_DIVERSITY) &&
175 !(ant->flags & ANTENNA_TX_DIVERSITY)) {
181 * If we have only sampled the data over the last period
182 * we should now harvest the data. Otherwise just evaluate
183 * the data. The latter should only be performed once
186 if (ant->flags & ANTENNA_MODE_SAMPLE) {
187 rt2x00lib_antenna_diversity_sample(rt2x00dev);
189 } else if (rt2x00dev->link.count & 1) {
190 rt2x00lib_antenna_diversity_eval(rt2x00dev);
197 void rt2x00link_update_stats(struct rt2x00_dev *rt2x00dev,
199 struct rxdone_entry_desc *rxdesc)
201 struct link *link = &rt2x00dev->link;
202 struct link_qual *qual = &rt2x00dev->link.qual;
203 struct link_ant *ant = &rt2x00dev->link.ant;
204 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
207 * No need to update the stats for !=STA interfaces
209 if (!rt2x00dev->intf_sta_count)
213 * Frame was received successfully since non-succesfull
214 * frames would have been dropped by the hardware.
219 * We are only interested in quality statistics from
220 * beacons which came from the BSS which we are
223 if (!ieee80211_is_beacon(hdr->frame_control) ||
224 !(rxdesc->dev_flags & RXDONE_MY_BSS))
230 ewma_add(&link->avg_rssi, -rxdesc->rssi);
233 * Update antenna RSSI
235 ewma_add(&ant->rssi_ant, -rxdesc->rssi);
238 void rt2x00link_start_tuner(struct rt2x00_dev *rt2x00dev)
240 struct link *link = &rt2x00dev->link;
243 * Link tuning should only be performed when
244 * an active sta interface exists. AP interfaces
245 * don't need link tuning and monitor mode interfaces
246 * should never have to work with link tuners.
248 if (!rt2x00dev->intf_sta_count)
252 * While scanning, link tuning is disabled. By default
253 * the most sensitive settings will be used to make sure
254 * that all beacons and probe responses will be received
257 if (test_bit(DEVICE_STATE_SCANNING, &rt2x00dev->flags))
260 rt2x00link_reset_tuner(rt2x00dev, false);
262 if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
263 ieee80211_queue_delayed_work(rt2x00dev->hw,
264 &link->work, LINK_TUNE_INTERVAL);
267 void rt2x00link_stop_tuner(struct rt2x00_dev *rt2x00dev)
269 cancel_delayed_work_sync(&rt2x00dev->link.work);
272 void rt2x00link_reset_tuner(struct rt2x00_dev *rt2x00dev, bool antenna)
274 struct link_qual *qual = &rt2x00dev->link.qual;
275 u8 vgc_level = qual->vgc_level_reg;
277 if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
281 * Reset link information.
282 * Both the currently active vgc level as well as
283 * the link tuner counter should be reset. Resetting
284 * the counter is important for devices where the
285 * device should only perform link tuning during the
286 * first minute after being enabled.
288 rt2x00dev->link.count = 0;
289 memset(qual, 0, sizeof(*qual));
290 ewma_init(&rt2x00dev->link.avg_rssi, RT2X00_EWMA_FACTOR,
294 * Restore the VGC level as stored in the registers,
295 * the driver can use this to determine if the register
296 * must be updated during reset or not.
298 qual->vgc_level_reg = vgc_level;
301 * Reset the link tuner.
303 rt2x00dev->ops->lib->reset_tuner(rt2x00dev, qual);
306 rt2x00link_antenna_reset(rt2x00dev);
309 static void rt2x00link_reset_qual(struct rt2x00_dev *rt2x00dev)
311 struct link_qual *qual = &rt2x00dev->link.qual;
313 qual->rx_success = 0;
315 qual->tx_success = 0;
319 static void rt2x00link_tuner(struct work_struct *work)
321 struct rt2x00_dev *rt2x00dev =
322 container_of(work, struct rt2x00_dev, link.work.work);
323 struct link *link = &rt2x00dev->link;
324 struct link_qual *qual = &rt2x00dev->link.qual;
327 * When the radio is shutting down we should
328 * immediately cease all link tuning.
330 if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags) ||
331 test_bit(DEVICE_STATE_SCANNING, &rt2x00dev->flags))
337 rt2x00dev->ops->lib->link_stats(rt2x00dev, qual);
338 rt2x00dev->low_level_stats.dot11FCSErrorCount += qual->rx_failed;
341 * Update quality RSSI for link tuning,
342 * when we have received some frames and we managed to
343 * collect the RSSI data we could use this. Otherwise we
344 * must fallback to the default RSSI value.
346 if (!qual->rx_success)
347 qual->rssi = DEFAULT_RSSI;
349 qual->rssi = rt2x00link_get_avg_rssi(&link->avg_rssi);
352 * Check if link tuning is supported by the hardware, some hardware
353 * do not support link tuning at all, while other devices can disable
354 * the feature from the EEPROM.
356 if (rt2x00_has_cap_link_tuning(rt2x00dev))
357 rt2x00dev->ops->lib->link_tuner(rt2x00dev, qual, link->count);
360 * Send a signal to the led to update the led signal strength.
362 rt2x00leds_led_quality(rt2x00dev, qual->rssi);
365 * Evaluate antenna setup, make this the last step when
366 * rt2x00lib_antenna_diversity made changes the quality
367 * statistics will be reset.
369 if (rt2x00lib_antenna_diversity(rt2x00dev))
370 rt2x00link_reset_qual(rt2x00dev);
373 * Increase tuner counter, and reschedule the next link tuner run.
377 if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
378 ieee80211_queue_delayed_work(rt2x00dev->hw,
379 &link->work, LINK_TUNE_INTERVAL);
382 void rt2x00link_start_watchdog(struct rt2x00_dev *rt2x00dev)
384 struct link *link = &rt2x00dev->link;
386 if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags) &&
387 rt2x00dev->ops->lib->watchdog)
388 ieee80211_queue_delayed_work(rt2x00dev->hw,
389 &link->watchdog_work,
393 void rt2x00link_stop_watchdog(struct rt2x00_dev *rt2x00dev)
395 cancel_delayed_work_sync(&rt2x00dev->link.watchdog_work);
398 static void rt2x00link_watchdog(struct work_struct *work)
400 struct rt2x00_dev *rt2x00dev =
401 container_of(work, struct rt2x00_dev, link.watchdog_work.work);
402 struct link *link = &rt2x00dev->link;
405 * When the radio is shutting down we should
406 * immediately cease the watchdog monitoring.
408 if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
411 rt2x00dev->ops->lib->watchdog(rt2x00dev);
413 if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
414 ieee80211_queue_delayed_work(rt2x00dev->hw,
415 &link->watchdog_work,
419 void rt2x00link_start_agc(struct rt2x00_dev *rt2x00dev)
421 struct link *link = &rt2x00dev->link;
423 if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags) &&
424 rt2x00dev->ops->lib->gain_calibration)
425 ieee80211_queue_delayed_work(rt2x00dev->hw,
430 void rt2x00link_start_vcocal(struct rt2x00_dev *rt2x00dev)
432 struct link *link = &rt2x00dev->link;
434 if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags) &&
435 rt2x00dev->ops->lib->vco_calibration)
436 ieee80211_queue_delayed_work(rt2x00dev->hw,
441 void rt2x00link_stop_agc(struct rt2x00_dev *rt2x00dev)
443 cancel_delayed_work_sync(&rt2x00dev->link.agc_work);
446 void rt2x00link_stop_vcocal(struct rt2x00_dev *rt2x00dev)
448 cancel_delayed_work_sync(&rt2x00dev->link.vco_work);
451 static void rt2x00link_agc(struct work_struct *work)
453 struct rt2x00_dev *rt2x00dev =
454 container_of(work, struct rt2x00_dev, link.agc_work.work);
455 struct link *link = &rt2x00dev->link;
458 * When the radio is shutting down we should
459 * immediately cease the watchdog monitoring.
461 if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
464 rt2x00dev->ops->lib->gain_calibration(rt2x00dev);
466 if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
467 ieee80211_queue_delayed_work(rt2x00dev->hw,
472 static void rt2x00link_vcocal(struct work_struct *work)
474 struct rt2x00_dev *rt2x00dev =
475 container_of(work, struct rt2x00_dev, link.vco_work.work);
476 struct link *link = &rt2x00dev->link;
479 * When the radio is shutting down we should
480 * immediately cease the VCO calibration.
482 if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags))
485 rt2x00dev->ops->lib->vco_calibration(rt2x00dev);
487 if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags))
488 ieee80211_queue_delayed_work(rt2x00dev->hw,
493 void rt2x00link_register(struct rt2x00_dev *rt2x00dev)
495 INIT_DELAYED_WORK(&rt2x00dev->link.agc_work, rt2x00link_agc);
496 if (rt2x00_has_cap_vco_recalibration(rt2x00dev))
497 INIT_DELAYED_WORK(&rt2x00dev->link.vco_work, rt2x00link_vcocal);
498 INIT_DELAYED_WORK(&rt2x00dev->link.watchdog_work, rt2x00link_watchdog);
499 INIT_DELAYED_WORK(&rt2x00dev->link.work, rt2x00link_tuner);