Commit | Line | Data |
---|---|---|
84e3196f | 1 | /* |
9c9a0d14 | 2 | Copyright (C) 2004 - 2009 Ivo van Doorn <IvDoorn@gmail.com> |
84e3196f ID |
3 | <http://rt2x00.serialmonkey.com> |
4 | ||
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. | |
9 | ||
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. | |
14 | ||
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. | |
19 | */ | |
20 | ||
21 | /* | |
22 | Module: rt2x00lib | |
23 | Abstract: rt2x00 generic link tuning routines. | |
24 | */ | |
25 | ||
26 | #include <linux/kernel.h> | |
27 | #include <linux/module.h> | |
28 | ||
29 | #include "rt2x00.h" | |
30 | #include "rt2x00lib.h" | |
31 | ||
5352ff65 ID |
32 | /* |
33 | * When we lack RSSI information return something less then -80 to | |
34 | * tell the driver to tune the device to maximum sensitivity. | |
35 | */ | |
36 | #define DEFAULT_RSSI -128 | |
37 | ||
66679a65 LE |
38 | /* |
39 | * Helper struct and macro to work with moving/walking averages. | |
5352ff65 ID |
40 | * When adding a value to the average value the following calculation |
41 | * is needed: | |
42 | * | |
43 | * avg_rssi = ((avg_rssi * 7) + rssi) / 8; | |
44 | * | |
45 | * The advantage of this approach is that we only need 1 variable | |
46 | * to store the average in (No need for a count and a total). | |
47 | * But more importantly, normal average values will over time | |
48 | * move less and less towards newly added values this results | |
49 | * that with link tuning, the device can have a very good RSSI | |
50 | * for a few minutes but when the device is moved away from the AP | |
51 | * the average will not decrease fast enough to compensate. | |
52 | * The walking average compensates this and will move towards | |
66679a65 LE |
53 | * the new values correctly allowing a effective link tuning, |
54 | * the speed of the average moving towards other values depends | |
55 | * on the value for the number of samples. The higher the number | |
56 | * of samples, the slower the average will move. | |
57 | * We use two variables to keep track of the average value to | |
58 | * compensate for the rounding errors. This can be a significant | |
59 | * error (>5dBm) if the factor is too low. | |
5352ff65 | 60 | */ |
66679a65 LE |
61 | #define AVG_SAMPLES 8 |
62 | #define AVG_FACTOR 1000 | |
63 | #define MOVING_AVERAGE(__avg, __val) \ | |
64 | ({ \ | |
65 | struct avg_val __new; \ | |
66 | __new.avg_weight = \ | |
67 | (__avg).avg_weight ? \ | |
68 | ((((__avg).avg_weight * ((AVG_SAMPLES) - 1)) + \ | |
69 | ((__val) * (AVG_FACTOR))) / \ | |
027e8fd1 | 70 | (AVG_SAMPLES)) : \ |
66679a65 LE |
71 | ((__val) * (AVG_FACTOR)); \ |
72 | __new.avg = __new.avg_weight / (AVG_FACTOR); \ | |
73 | __new; \ | |
74 | }) | |
5352ff65 | 75 | |
84e3196f ID |
76 | static int rt2x00link_antenna_get_link_rssi(struct rt2x00_dev *rt2x00dev) |
77 | { | |
78 | struct link_ant *ant = &rt2x00dev->link.ant; | |
79 | ||
66679a65 LE |
80 | if (ant->rssi_ant.avg && rt2x00dev->link.qual.rx_success) |
81 | return ant->rssi_ant.avg; | |
84e3196f ID |
82 | return DEFAULT_RSSI; |
83 | } | |
84 | ||
193df183 | 85 | static int rt2x00link_antenna_get_rssi_history(struct rt2x00_dev *rt2x00dev) |
84e3196f ID |
86 | { |
87 | struct link_ant *ant = &rt2x00dev->link.ant; | |
88 | ||
193df183 LE |
89 | if (ant->rssi_history) |
90 | return ant->rssi_history; | |
84e3196f ID |
91 | return DEFAULT_RSSI; |
92 | } | |
84e3196f ID |
93 | |
94 | static void rt2x00link_antenna_update_rssi_history(struct rt2x00_dev *rt2x00dev, | |
84e3196f ID |
95 | int rssi) |
96 | { | |
97 | struct link_ant *ant = &rt2x00dev->link.ant; | |
193df183 | 98 | ant->rssi_history = rssi; |
84e3196f | 99 | } |
84e3196f ID |
100 | |
101 | static void rt2x00link_antenna_reset(struct rt2x00_dev *rt2x00dev) | |
102 | { | |
66679a65 LE |
103 | rt2x00dev->link.ant.rssi_ant.avg = 0; |
104 | rt2x00dev->link.ant.rssi_ant.avg_weight = 0; | |
84e3196f ID |
105 | } |
106 | ||
107 | static void rt2x00lib_antenna_diversity_sample(struct rt2x00_dev *rt2x00dev) | |
108 | { | |
109 | struct link_ant *ant = &rt2x00dev->link.ant; | |
110 | struct antenna_setup new_ant; | |
193df183 LE |
111 | int other_antenna; |
112 | ||
113 | int sample_current = rt2x00link_antenna_get_link_rssi(rt2x00dev); | |
114 | int sample_other = rt2x00link_antenna_get_rssi_history(rt2x00dev); | |
84e3196f ID |
115 | |
116 | memcpy(&new_ant, &ant->active, sizeof(new_ant)); | |
117 | ||
118 | /* | |
119 | * We are done sampling. Now we should evaluate the results. | |
120 | */ | |
121 | ant->flags &= ~ANTENNA_MODE_SAMPLE; | |
122 | ||
123 | /* | |
124 | * During the last period we have sampled the RSSI | |
49513481 | 125 | * from both antennas. It now is time to determine |
84e3196f ID |
126 | * which antenna demonstrated the best performance. |
127 | * When we are already on the antenna with the best | |
193df183 LE |
128 | * performance, just create a good starting point |
129 | * for the history and we are done. | |
84e3196f | 130 | */ |
193df183 LE |
131 | if (sample_current >= sample_other) { |
132 | rt2x00link_antenna_update_rssi_history(rt2x00dev, | |
133 | sample_current); | |
84e3196f | 134 | return; |
193df183 LE |
135 | } |
136 | ||
137 | other_antenna = (ant->active.rx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A; | |
84e3196f ID |
138 | |
139 | if (ant->flags & ANTENNA_RX_DIVERSITY) | |
193df183 | 140 | new_ant.rx = other_antenna; |
84e3196f ID |
141 | |
142 | if (ant->flags & ANTENNA_TX_DIVERSITY) | |
193df183 | 143 | new_ant.tx = other_antenna; |
84e3196f | 144 | |
eb87eaac | 145 | rt2x00lib_config_antenna(rt2x00dev, new_ant); |
84e3196f ID |
146 | } |
147 | ||
148 | static void rt2x00lib_antenna_diversity_eval(struct rt2x00_dev *rt2x00dev) | |
149 | { | |
150 | struct link_ant *ant = &rt2x00dev->link.ant; | |
151 | struct antenna_setup new_ant; | |
152 | int rssi_curr; | |
153 | int rssi_old; | |
154 | ||
155 | memcpy(&new_ant, &ant->active, sizeof(new_ant)); | |
156 | ||
157 | /* | |
158 | * Get current RSSI value along with the historical value, | |
159 | * after that update the history with the current value. | |
160 | */ | |
161 | rssi_curr = rt2x00link_antenna_get_link_rssi(rt2x00dev); | |
193df183 LE |
162 | rssi_old = rt2x00link_antenna_get_rssi_history(rt2x00dev); |
163 | rt2x00link_antenna_update_rssi_history(rt2x00dev, rssi_curr); | |
84e3196f ID |
164 | |
165 | /* | |
166 | * Legacy driver indicates that we should swap antenna's | |
167 | * when the difference in RSSI is greater that 5. This | |
168 | * also should be done when the RSSI was actually better | |
169 | * then the previous sample. | |
170 | * When the difference exceeds the threshold we should | |
171 | * sample the rssi from the other antenna to make a valid | |
172 | * comparison between the 2 antennas. | |
173 | */ | |
174 | if (abs(rssi_curr - rssi_old) < 5) | |
175 | return; | |
176 | ||
177 | ant->flags |= ANTENNA_MODE_SAMPLE; | |
178 | ||
179 | if (ant->flags & ANTENNA_RX_DIVERSITY) | |
180 | new_ant.rx = (new_ant.rx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A; | |
181 | ||
182 | if (ant->flags & ANTENNA_TX_DIVERSITY) | |
183 | new_ant.tx = (new_ant.tx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A; | |
184 | ||
eb87eaac | 185 | rt2x00lib_config_antenna(rt2x00dev, new_ant); |
84e3196f ID |
186 | } |
187 | ||
193df183 | 188 | static bool rt2x00lib_antenna_diversity(struct rt2x00_dev *rt2x00dev) |
84e3196f ID |
189 | { |
190 | struct link_ant *ant = &rt2x00dev->link.ant; | |
191 | ||
192 | /* | |
193 | * Determine if software diversity is enabled for | |
194 | * either the TX or RX antenna (or both). | |
195 | * Always perform this check since within the link | |
196 | * tuner interval the configuration might have changed. | |
197 | */ | |
85f4d648 LE |
198 | ant->flags &= ~ANTENNA_RX_DIVERSITY; |
199 | ant->flags &= ~ANTENNA_TX_DIVERSITY; | |
84e3196f ID |
200 | |
201 | if (rt2x00dev->default_ant.rx == ANTENNA_SW_DIVERSITY) | |
85f4d648 | 202 | ant->flags |= ANTENNA_RX_DIVERSITY; |
84e3196f | 203 | if (rt2x00dev->default_ant.tx == ANTENNA_SW_DIVERSITY) |
85f4d648 | 204 | ant->flags |= ANTENNA_TX_DIVERSITY; |
84e3196f ID |
205 | |
206 | if (!(ant->flags & ANTENNA_RX_DIVERSITY) && | |
207 | !(ant->flags & ANTENNA_TX_DIVERSITY)) { | |
208 | ant->flags = 0; | |
193df183 | 209 | return true; |
84e3196f ID |
210 | } |
211 | ||
212 | /* | |
213 | * If we have only sampled the data over the last period | |
214 | * we should now harvest the data. Otherwise just evaluate | |
215 | * the data. The latter should only be performed once | |
216 | * every 2 seconds. | |
217 | */ | |
193df183 | 218 | if (ant->flags & ANTENNA_MODE_SAMPLE) { |
84e3196f | 219 | rt2x00lib_antenna_diversity_sample(rt2x00dev); |
193df183 LE |
220 | return true; |
221 | } else if (rt2x00dev->link.count & 1) { | |
84e3196f | 222 | rt2x00lib_antenna_diversity_eval(rt2x00dev); |
193df183 LE |
223 | return true; |
224 | } | |
225 | ||
226 | return false; | |
84e3196f ID |
227 | } |
228 | ||
229 | void rt2x00link_update_stats(struct rt2x00_dev *rt2x00dev, | |
230 | struct sk_buff *skb, | |
231 | struct rxdone_entry_desc *rxdesc) | |
232 | { | |
5352ff65 | 233 | struct link *link = &rt2x00dev->link; |
84e3196f ID |
234 | struct link_qual *qual = &rt2x00dev->link.qual; |
235 | struct link_ant *ant = &rt2x00dev->link.ant; | |
236 | struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; | |
84e3196f | 237 | |
a23c2208 HS |
238 | /* |
239 | * No need to update the stats for !=STA interfaces | |
240 | */ | |
241 | if (!rt2x00dev->intf_sta_count) | |
242 | return; | |
243 | ||
84e3196f ID |
244 | /* |
245 | * Frame was received successfully since non-succesfull | |
246 | * frames would have been dropped by the hardware. | |
247 | */ | |
248 | qual->rx_success++; | |
249 | ||
250 | /* | |
251 | * We are only interested in quality statistics from | |
252 | * beacons which came from the BSS which we are | |
253 | * associated with. | |
254 | */ | |
255 | if (!ieee80211_is_beacon(hdr->frame_control) || | |
256 | !(rxdesc->dev_flags & RXDONE_MY_BSS)) | |
257 | return; | |
258 | ||
259 | /* | |
260 | * Update global RSSI | |
261 | */ | |
66679a65 | 262 | link->avg_rssi = MOVING_AVERAGE(link->avg_rssi, rxdesc->rssi); |
84e3196f ID |
263 | |
264 | /* | |
265 | * Update antenna RSSI | |
266 | */ | |
66679a65 | 267 | ant->rssi_ant = MOVING_AVERAGE(ant->rssi_ant, rxdesc->rssi); |
84e3196f ID |
268 | } |
269 | ||
84e3196f ID |
270 | void rt2x00link_start_tuner(struct rt2x00_dev *rt2x00dev) |
271 | { | |
5352ff65 | 272 | struct link *link = &rt2x00dev->link; |
84e3196f ID |
273 | |
274 | /* | |
275 | * Link tuning should only be performed when | |
8654b79f HS |
276 | * an active sta interface exists. AP interfaces |
277 | * don't need link tuning and monitor mode interfaces | |
278 | * should never have to work with link tuners. | |
84e3196f | 279 | */ |
8654b79f | 280 | if (!rt2x00dev->intf_sta_count) |
84e3196f ID |
281 | return; |
282 | ||
d8147f9d ID |
283 | /** |
284 | * While scanning, link tuning is disabled. By default | |
285 | * the most sensitive settings will be used to make sure | |
286 | * that all beacons and probe responses will be recieved | |
287 | * during the scan. | |
288 | */ | |
289 | if (test_bit(DEVICE_STATE_SCANNING, &rt2x00dev->flags)) | |
290 | return; | |
291 | ||
84e3196f ID |
292 | rt2x00link_reset_tuner(rt2x00dev, false); |
293 | ||
66f84d65 SC |
294 | if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags)) |
295 | ieee80211_queue_delayed_work(rt2x00dev->hw, | |
296 | &link->work, LINK_TUNE_INTERVAL); | |
84e3196f ID |
297 | } |
298 | ||
299 | void rt2x00link_stop_tuner(struct rt2x00_dev *rt2x00dev) | |
300 | { | |
301 | cancel_delayed_work_sync(&rt2x00dev->link.work); | |
302 | } | |
303 | ||
304 | void rt2x00link_reset_tuner(struct rt2x00_dev *rt2x00dev, bool antenna) | |
305 | { | |
5352ff65 | 306 | struct link_qual *qual = &rt2x00dev->link.qual; |
223dcc26 | 307 | u8 vgc_level = qual->vgc_level_reg; |
5352ff65 | 308 | |
84e3196f ID |
309 | if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags)) |
310 | return; | |
311 | ||
312 | /* | |
313 | * Reset link information. | |
314 | * Both the currently active vgc level as well as | |
315 | * the link tuner counter should be reset. Resetting | |
316 | * the counter is important for devices where the | |
317 | * device should only perform link tuning during the | |
318 | * first minute after being enabled. | |
319 | */ | |
320 | rt2x00dev->link.count = 0; | |
5352ff65 | 321 | memset(qual, 0, sizeof(*qual)); |
84e3196f | 322 | |
223dcc26 ID |
323 | /* |
324 | * Restore the VGC level as stored in the registers, | |
325 | * the driver can use this to determine if the register | |
326 | * must be updated during reset or not. | |
327 | */ | |
328 | qual->vgc_level_reg = vgc_level; | |
329 | ||
84e3196f ID |
330 | /* |
331 | * Reset the link tuner. | |
332 | */ | |
5352ff65 | 333 | rt2x00dev->ops->lib->reset_tuner(rt2x00dev, qual); |
84e3196f ID |
334 | |
335 | if (antenna) | |
336 | rt2x00link_antenna_reset(rt2x00dev); | |
337 | } | |
338 | ||
a57e2e84 | 339 | static void rt2x00link_reset_qual(struct rt2x00_dev *rt2x00dev) |
64abd803 ID |
340 | { |
341 | struct link_qual *qual = &rt2x00dev->link.qual; | |
342 | ||
343 | qual->rx_success = 0; | |
344 | qual->rx_failed = 0; | |
345 | qual->tx_success = 0; | |
346 | qual->tx_failed = 0; | |
347 | } | |
348 | ||
84e3196f ID |
349 | static void rt2x00link_tuner(struct work_struct *work) |
350 | { | |
351 | struct rt2x00_dev *rt2x00dev = | |
352 | container_of(work, struct rt2x00_dev, link.work.work); | |
5352ff65 | 353 | struct link *link = &rt2x00dev->link; |
84e3196f ID |
354 | struct link_qual *qual = &rt2x00dev->link.qual; |
355 | ||
356 | /* | |
357 | * When the radio is shutting down we should | |
358 | * immediately cease all link tuning. | |
359 | */ | |
d8147f9d ID |
360 | if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags) || |
361 | test_bit(DEVICE_STATE_SCANNING, &rt2x00dev->flags)) | |
84e3196f ID |
362 | return; |
363 | ||
364 | /* | |
365 | * Update statistics. | |
366 | */ | |
367 | rt2x00dev->ops->lib->link_stats(rt2x00dev, qual); | |
368 | rt2x00dev->low_level_stats.dot11FCSErrorCount += qual->rx_failed; | |
369 | ||
5352ff65 ID |
370 | /* |
371 | * Update quality RSSI for link tuning, | |
372 | * when we have received some frames and we managed to | |
373 | * collect the RSSI data we could use this. Otherwise we | |
374 | * must fallback to the default RSSI value. | |
375 | */ | |
66679a65 | 376 | if (!link->avg_rssi.avg || !qual->rx_success) |
5352ff65 ID |
377 | qual->rssi = DEFAULT_RSSI; |
378 | else | |
66679a65 | 379 | qual->rssi = link->avg_rssi.avg; |
5352ff65 | 380 | |
84e3196f | 381 | /* |
27df2a9c ID |
382 | * Check if link tuning is supported by the hardware, some hardware |
383 | * do not support link tuning at all, while other devices can disable | |
384 | * the feature from the EEPROM. | |
84e3196f | 385 | */ |
27df2a9c | 386 | if (test_bit(DRIVER_SUPPORT_LINK_TUNING, &rt2x00dev->flags)) |
5352ff65 | 387 | rt2x00dev->ops->lib->link_tuner(rt2x00dev, qual, link->count); |
84e3196f | 388 | |
84e3196f ID |
389 | /* |
390 | * Send a signal to the led to update the led signal strength. | |
391 | */ | |
66679a65 | 392 | rt2x00leds_led_quality(rt2x00dev, qual->rssi); |
84e3196f ID |
393 | |
394 | /* | |
193df183 LE |
395 | * Evaluate antenna setup, make this the last step when |
396 | * rt2x00lib_antenna_diversity made changes the quality | |
397 | * statistics will be reset. | |
64abd803 | 398 | */ |
193df183 LE |
399 | if (rt2x00lib_antenna_diversity(rt2x00dev)) |
400 | rt2x00link_reset_qual(rt2x00dev); | |
64abd803 | 401 | |
84e3196f ID |
402 | /* |
403 | * Increase tuner counter, and reschedule the next link tuner run. | |
404 | */ | |
5352ff65 | 405 | link->count++; |
66f84d65 SC |
406 | |
407 | if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags)) | |
408 | ieee80211_queue_delayed_work(rt2x00dev->hw, | |
409 | &link->work, LINK_TUNE_INTERVAL); | |
84e3196f ID |
410 | } |
411 | ||
c965c74b ID |
412 | void rt2x00link_start_watchdog(struct rt2x00_dev *rt2x00dev) |
413 | { | |
414 | struct link *link = &rt2x00dev->link; | |
415 | ||
416 | if (!test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags) || | |
417 | !test_bit(DRIVER_SUPPORT_WATCHDOG, &rt2x00dev->flags)) | |
418 | return; | |
419 | ||
0439f536 ID |
420 | ieee80211_queue_delayed_work(rt2x00dev->hw, |
421 | &link->watchdog_work, WATCHDOG_INTERVAL); | |
c965c74b ID |
422 | } |
423 | ||
424 | void rt2x00link_stop_watchdog(struct rt2x00_dev *rt2x00dev) | |
425 | { | |
426 | cancel_delayed_work_sync(&rt2x00dev->link.watchdog_work); | |
427 | } | |
428 | ||
429 | static void rt2x00link_watchdog(struct work_struct *work) | |
430 | { | |
431 | struct rt2x00_dev *rt2x00dev = | |
432 | container_of(work, struct rt2x00_dev, link.watchdog_work.work); | |
433 | struct link *link = &rt2x00dev->link; | |
434 | ||
435 | /* | |
436 | * When the radio is shutting down we should | |
437 | * immediately cease the watchdog monitoring. | |
438 | */ | |
439 | if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags)) | |
440 | return; | |
441 | ||
442 | rt2x00dev->ops->lib->watchdog(rt2x00dev); | |
443 | ||
444 | if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags)) | |
0439f536 ID |
445 | ieee80211_queue_delayed_work(rt2x00dev->hw, |
446 | &link->watchdog_work, | |
447 | WATCHDOG_INTERVAL); | |
c965c74b ID |
448 | } |
449 | ||
84e3196f ID |
450 | void rt2x00link_register(struct rt2x00_dev *rt2x00dev) |
451 | { | |
c965c74b | 452 | INIT_DELAYED_WORK(&rt2x00dev->link.watchdog_work, rt2x00link_watchdog); |
84e3196f ID |
453 | INIT_DELAYED_WORK(&rt2x00dev->link.work, rt2x00link_tuner); |
454 | } |