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84e3196f | 1 | /* |
4e54c711 | 2 | Copyright (C) 2004 - 2009 rt2x00 SourceForge Project |
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 | ||
38 | /* | |
39 | * When no TX/RX percentage could be calculated due to lack of | |
40 | * frames on the air, we fallback to a percentage of 50%. | |
41 | * This will assure we will get at least get some decent value | |
42 | * when the link tuner starts. | |
43 | * The value will be dropped and overwritten with the correct (measured) | |
44 | * value anyway during the first run of the link tuner. | |
45 | */ | |
46 | #define DEFAULT_PERCENTAGE 50 | |
47 | ||
48 | /* | |
49 | * Small helper macro to work with moving/walking averages. | |
50 | * When adding a value to the average value the following calculation | |
51 | * is needed: | |
52 | * | |
53 | * avg_rssi = ((avg_rssi * 7) + rssi) / 8; | |
54 | * | |
55 | * The advantage of this approach is that we only need 1 variable | |
56 | * to store the average in (No need for a count and a total). | |
57 | * But more importantly, normal average values will over time | |
58 | * move less and less towards newly added values this results | |
59 | * that with link tuning, the device can have a very good RSSI | |
60 | * for a few minutes but when the device is moved away from the AP | |
61 | * the average will not decrease fast enough to compensate. | |
62 | * The walking average compensates this and will move towards | |
63 | * the new values correctly allowing a effective link tuning. | |
64 | */ | |
65 | #define MOVING_AVERAGE(__avg, __val, __samples) \ | |
66 | ( (((__avg) * ((__samples) - 1)) + (__val)) / (__samples) ) | |
67 | ||
68 | /* | |
69 | * Small helper macro for percentage calculation | |
70 | * This is a very simple macro with the only catch that it will | |
71 | * produce a default value in case no total value was provided. | |
72 | */ | |
73 | #define PERCENTAGE(__value, __total) \ | |
74 | ( (__total) ? (((__value) * 100) / (__total)) : (DEFAULT_PERCENTAGE) ) | |
75 | ||
76 | /* | |
77 | * For calculating the Signal quality we have determined | |
78 | * the total number of success and failed RX and TX frames. | |
79 | * With the addition of the average RSSI value we can determine | |
80 | * the link quality using the following algorithm: | |
81 | * | |
82 | * rssi_percentage = (avg_rssi * 100) / rssi_offset | |
83 | * rx_percentage = (rx_success * 100) / rx_total | |
84 | * tx_percentage = (tx_success * 100) / tx_total | |
85 | * avg_signal = ((WEIGHT_RSSI * avg_rssi) + | |
86 | * (WEIGHT_TX * tx_percentage) + | |
87 | * (WEIGHT_RX * rx_percentage)) / 100 | |
88 | * | |
89 | * This value should then be checked to not be greater then 100. | |
90 | * This means the values of WEIGHT_RSSI, WEIGHT_RX, WEIGHT_TX must | |
91 | * sum up to 100 as well. | |
92 | */ | |
93 | #define WEIGHT_RSSI 20 | |
94 | #define WEIGHT_RX 40 | |
95 | #define WEIGHT_TX 40 | |
96 | ||
84e3196f ID |
97 | static int rt2x00link_antenna_get_link_rssi(struct rt2x00_dev *rt2x00dev) |
98 | { | |
99 | struct link_ant *ant = &rt2x00dev->link.ant; | |
100 | ||
101 | if (ant->rssi_ant && rt2x00dev->link.qual.rx_success) | |
102 | return ant->rssi_ant; | |
103 | return DEFAULT_RSSI; | |
104 | } | |
105 | ||
106 | static int rt2x00link_antenna_get_rssi_history(struct rt2x00_dev *rt2x00dev, | |
107 | enum antenna antenna) | |
108 | { | |
109 | struct link_ant *ant = &rt2x00dev->link.ant; | |
110 | ||
111 | if (ant->rssi_history[antenna - ANTENNA_A]) | |
112 | return ant->rssi_history[antenna - ANTENNA_A]; | |
113 | return DEFAULT_RSSI; | |
114 | } | |
115 | /* Small wrapper for rt2x00link_antenna_get_rssi_history() */ | |
116 | #define rt2x00link_antenna_get_rssi_rx_history(__dev) \ | |
117 | rt2x00link_antenna_get_rssi_history((__dev), \ | |
118 | (__dev)->link.ant.active.rx) | |
119 | #define rt2x00link_antenna_get_rssi_tx_history(__dev) \ | |
120 | rt2x00link_antenna_get_rssi_history((__dev), \ | |
121 | (__dev)->link.ant.active.tx) | |
122 | ||
123 | static void rt2x00link_antenna_update_rssi_history(struct rt2x00_dev *rt2x00dev, | |
124 | enum antenna antenna, | |
125 | int rssi) | |
126 | { | |
127 | struct link_ant *ant = &rt2x00dev->link.ant; | |
128 | ant->rssi_history[ant->active.rx - ANTENNA_A] = rssi; | |
129 | } | |
130 | /* Small wrapper for rt2x00link_antenna_get_rssi_history() */ | |
131 | #define rt2x00link_antenna_update_rssi_rx_history(__dev, __rssi) \ | |
132 | rt2x00link_antenna_update_rssi_history((__dev), \ | |
133 | (__dev)->link.ant.active.rx, \ | |
134 | (__rssi)) | |
135 | #define rt2x00link_antenna_update_rssi_tx_history(__dev, __rssi) \ | |
136 | rt2x00link_antenna_update_rssi_history((__dev), \ | |
137 | (__dev)->link.ant.active.tx, \ | |
138 | (__rssi)) | |
139 | ||
140 | static void rt2x00link_antenna_reset(struct rt2x00_dev *rt2x00dev) | |
141 | { | |
142 | rt2x00dev->link.ant.rssi_ant = 0; | |
143 | } | |
144 | ||
145 | static void rt2x00lib_antenna_diversity_sample(struct rt2x00_dev *rt2x00dev) | |
146 | { | |
147 | struct link_ant *ant = &rt2x00dev->link.ant; | |
148 | struct antenna_setup new_ant; | |
149 | int sample_a = rt2x00link_antenna_get_rssi_history(rt2x00dev, ANTENNA_A); | |
150 | int sample_b = rt2x00link_antenna_get_rssi_history(rt2x00dev, ANTENNA_B); | |
151 | ||
152 | memcpy(&new_ant, &ant->active, sizeof(new_ant)); | |
153 | ||
154 | /* | |
155 | * We are done sampling. Now we should evaluate the results. | |
156 | */ | |
157 | ant->flags &= ~ANTENNA_MODE_SAMPLE; | |
158 | ||
159 | /* | |
160 | * During the last period we have sampled the RSSI | |
161 | * from both antenna's. It now is time to determine | |
162 | * which antenna demonstrated the best performance. | |
163 | * When we are already on the antenna with the best | |
164 | * performance, then there really is nothing for us | |
165 | * left to do. | |
166 | */ | |
167 | if (sample_a == sample_b) | |
168 | return; | |
169 | ||
170 | if (ant->flags & ANTENNA_RX_DIVERSITY) | |
171 | new_ant.rx = (sample_a > sample_b) ? ANTENNA_A : ANTENNA_B; | |
172 | ||
173 | if (ant->flags & ANTENNA_TX_DIVERSITY) | |
174 | new_ant.tx = (sample_a > sample_b) ? ANTENNA_A : ANTENNA_B; | |
175 | ||
176 | rt2x00lib_config_antenna(rt2x00dev, &new_ant); | |
177 | } | |
178 | ||
179 | static void rt2x00lib_antenna_diversity_eval(struct rt2x00_dev *rt2x00dev) | |
180 | { | |
181 | struct link_ant *ant = &rt2x00dev->link.ant; | |
182 | struct antenna_setup new_ant; | |
183 | int rssi_curr; | |
184 | int rssi_old; | |
185 | ||
186 | memcpy(&new_ant, &ant->active, sizeof(new_ant)); | |
187 | ||
188 | /* | |
189 | * Get current RSSI value along with the historical value, | |
190 | * after that update the history with the current value. | |
191 | */ | |
192 | rssi_curr = rt2x00link_antenna_get_link_rssi(rt2x00dev); | |
193 | rssi_old = rt2x00link_antenna_get_rssi_rx_history(rt2x00dev); | |
194 | rt2x00link_antenna_update_rssi_rx_history(rt2x00dev, rssi_curr); | |
195 | ||
196 | /* | |
197 | * Legacy driver indicates that we should swap antenna's | |
198 | * when the difference in RSSI is greater that 5. This | |
199 | * also should be done when the RSSI was actually better | |
200 | * then the previous sample. | |
201 | * When the difference exceeds the threshold we should | |
202 | * sample the rssi from the other antenna to make a valid | |
203 | * comparison between the 2 antennas. | |
204 | */ | |
205 | if (abs(rssi_curr - rssi_old) < 5) | |
206 | return; | |
207 | ||
208 | ant->flags |= ANTENNA_MODE_SAMPLE; | |
209 | ||
210 | if (ant->flags & ANTENNA_RX_DIVERSITY) | |
211 | new_ant.rx = (new_ant.rx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A; | |
212 | ||
213 | if (ant->flags & ANTENNA_TX_DIVERSITY) | |
214 | new_ant.tx = (new_ant.tx == ANTENNA_A) ? ANTENNA_B : ANTENNA_A; | |
215 | ||
216 | rt2x00lib_config_antenna(rt2x00dev, &new_ant); | |
217 | } | |
218 | ||
219 | static void rt2x00lib_antenna_diversity(struct rt2x00_dev *rt2x00dev) | |
220 | { | |
221 | struct link_ant *ant = &rt2x00dev->link.ant; | |
222 | ||
223 | /* | |
224 | * Determine if software diversity is enabled for | |
225 | * either the TX or RX antenna (or both). | |
226 | * Always perform this check since within the link | |
227 | * tuner interval the configuration might have changed. | |
228 | */ | |
229 | ant->flags &= ~ANTENNA_RX_DIVERSITY; | |
230 | ant->flags &= ~ANTENNA_TX_DIVERSITY; | |
231 | ||
232 | if (rt2x00dev->default_ant.rx == ANTENNA_SW_DIVERSITY) | |
233 | ant->flags |= ANTENNA_RX_DIVERSITY; | |
234 | if (rt2x00dev->default_ant.tx == ANTENNA_SW_DIVERSITY) | |
235 | ant->flags |= ANTENNA_TX_DIVERSITY; | |
236 | ||
237 | if (!(ant->flags & ANTENNA_RX_DIVERSITY) && | |
238 | !(ant->flags & ANTENNA_TX_DIVERSITY)) { | |
239 | ant->flags = 0; | |
240 | return; | |
241 | } | |
242 | ||
243 | /* | |
244 | * If we have only sampled the data over the last period | |
245 | * we should now harvest the data. Otherwise just evaluate | |
246 | * the data. The latter should only be performed once | |
247 | * every 2 seconds. | |
248 | */ | |
249 | if (ant->flags & ANTENNA_MODE_SAMPLE) | |
250 | rt2x00lib_antenna_diversity_sample(rt2x00dev); | |
251 | else if (rt2x00dev->link.count & 1) | |
252 | rt2x00lib_antenna_diversity_eval(rt2x00dev); | |
253 | } | |
254 | ||
255 | void rt2x00link_update_stats(struct rt2x00_dev *rt2x00dev, | |
256 | struct sk_buff *skb, | |
257 | struct rxdone_entry_desc *rxdesc) | |
258 | { | |
5352ff65 | 259 | struct link *link = &rt2x00dev->link; |
84e3196f ID |
260 | struct link_qual *qual = &rt2x00dev->link.qual; |
261 | struct link_ant *ant = &rt2x00dev->link.ant; | |
262 | struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; | |
263 | int avg_rssi = rxdesc->rssi; | |
264 | int ant_rssi = rxdesc->rssi; | |
265 | ||
266 | /* | |
267 | * Frame was received successfully since non-succesfull | |
268 | * frames would have been dropped by the hardware. | |
269 | */ | |
270 | qual->rx_success++; | |
271 | ||
272 | /* | |
273 | * We are only interested in quality statistics from | |
274 | * beacons which came from the BSS which we are | |
275 | * associated with. | |
276 | */ | |
277 | if (!ieee80211_is_beacon(hdr->frame_control) || | |
278 | !(rxdesc->dev_flags & RXDONE_MY_BSS)) | |
279 | return; | |
280 | ||
281 | /* | |
282 | * Update global RSSI | |
283 | */ | |
5352ff65 ID |
284 | if (link->avg_rssi) |
285 | avg_rssi = MOVING_AVERAGE(link->avg_rssi, rxdesc->rssi, 8); | |
286 | link->avg_rssi = avg_rssi; | |
84e3196f ID |
287 | |
288 | /* | |
289 | * Update antenna RSSI | |
290 | */ | |
291 | if (ant->rssi_ant) | |
292 | ant_rssi = MOVING_AVERAGE(ant->rssi_ant, rxdesc->rssi, 8); | |
293 | ant->rssi_ant = ant_rssi; | |
294 | } | |
295 | ||
296 | static void rt2x00link_precalculate_signal(struct rt2x00_dev *rt2x00dev) | |
297 | { | |
5352ff65 | 298 | struct link *link = &rt2x00dev->link; |
84e3196f ID |
299 | struct link_qual *qual = &rt2x00dev->link.qual; |
300 | ||
5352ff65 ID |
301 | link->rx_percentage = |
302 | PERCENTAGE(qual->rx_success, qual->rx_failed + qual->rx_success); | |
303 | link->tx_percentage = | |
304 | PERCENTAGE(qual->tx_success, qual->tx_failed + qual->tx_success); | |
84e3196f ID |
305 | } |
306 | ||
307 | int rt2x00link_calculate_signal(struct rt2x00_dev *rt2x00dev, int rssi) | |
308 | { | |
5352ff65 | 309 | struct link *link = &rt2x00dev->link; |
84e3196f ID |
310 | int rssi_percentage = 0; |
311 | int signal; | |
312 | ||
313 | /* | |
314 | * We need a positive value for the RSSI. | |
315 | */ | |
316 | if (rssi < 0) | |
317 | rssi += rt2x00dev->rssi_offset; | |
318 | ||
319 | /* | |
320 | * Calculate the different percentages, | |
321 | * which will be used for the signal. | |
322 | */ | |
5352ff65 | 323 | rssi_percentage = PERCENTAGE(rssi, rt2x00dev->rssi_offset); |
84e3196f ID |
324 | |
325 | /* | |
326 | * Add the individual percentages and use the WEIGHT | |
327 | * defines to calculate the current link signal. | |
328 | */ | |
329 | signal = ((WEIGHT_RSSI * rssi_percentage) + | |
5352ff65 ID |
330 | (WEIGHT_TX * link->tx_percentage) + |
331 | (WEIGHT_RX * link->rx_percentage)) / 100; | |
84e3196f ID |
332 | |
333 | return max_t(int, signal, 100); | |
334 | } | |
335 | ||
336 | void rt2x00link_start_tuner(struct rt2x00_dev *rt2x00dev) | |
337 | { | |
5352ff65 | 338 | struct link *link = &rt2x00dev->link; |
84e3196f ID |
339 | |
340 | /* | |
341 | * Link tuning should only be performed when | |
342 | * an active sta or master interface exists. | |
343 | * Single monitor mode interfaces should never have | |
344 | * work with link tuners. | |
345 | */ | |
346 | if (!rt2x00dev->intf_ap_count && !rt2x00dev->intf_sta_count) | |
347 | return; | |
348 | ||
5352ff65 ID |
349 | link->rx_percentage = DEFAULT_PERCENTAGE; |
350 | link->tx_percentage = DEFAULT_PERCENTAGE; | |
84e3196f ID |
351 | |
352 | rt2x00link_reset_tuner(rt2x00dev, false); | |
353 | ||
354 | queue_delayed_work(rt2x00dev->hw->workqueue, | |
5352ff65 | 355 | &link->work, LINK_TUNE_INTERVAL); |
84e3196f ID |
356 | } |
357 | ||
358 | void rt2x00link_stop_tuner(struct rt2x00_dev *rt2x00dev) | |
359 | { | |
360 | cancel_delayed_work_sync(&rt2x00dev->link.work); | |
361 | } | |
362 | ||
363 | void rt2x00link_reset_tuner(struct rt2x00_dev *rt2x00dev, bool antenna) | |
364 | { | |
5352ff65 ID |
365 | struct link_qual *qual = &rt2x00dev->link.qual; |
366 | ||
84e3196f ID |
367 | if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags)) |
368 | return; | |
369 | ||
370 | /* | |
371 | * Reset link information. | |
372 | * Both the currently active vgc level as well as | |
373 | * the link tuner counter should be reset. Resetting | |
374 | * the counter is important for devices where the | |
375 | * device should only perform link tuning during the | |
376 | * first minute after being enabled. | |
377 | */ | |
378 | rt2x00dev->link.count = 0; | |
5352ff65 | 379 | memset(qual, 0, sizeof(*qual)); |
84e3196f ID |
380 | |
381 | /* | |
382 | * Reset the link tuner. | |
383 | */ | |
5352ff65 | 384 | rt2x00dev->ops->lib->reset_tuner(rt2x00dev, qual); |
84e3196f ID |
385 | |
386 | if (antenna) | |
387 | rt2x00link_antenna_reset(rt2x00dev); | |
388 | } | |
389 | ||
a57e2e84 | 390 | static void rt2x00link_reset_qual(struct rt2x00_dev *rt2x00dev) |
64abd803 ID |
391 | { |
392 | struct link_qual *qual = &rt2x00dev->link.qual; | |
393 | ||
394 | qual->rx_success = 0; | |
395 | qual->rx_failed = 0; | |
396 | qual->tx_success = 0; | |
397 | qual->tx_failed = 0; | |
398 | } | |
399 | ||
84e3196f ID |
400 | static void rt2x00link_tuner(struct work_struct *work) |
401 | { | |
402 | struct rt2x00_dev *rt2x00dev = | |
403 | container_of(work, struct rt2x00_dev, link.work.work); | |
5352ff65 | 404 | struct link *link = &rt2x00dev->link; |
84e3196f ID |
405 | struct link_qual *qual = &rt2x00dev->link.qual; |
406 | ||
407 | /* | |
408 | * When the radio is shutting down we should | |
409 | * immediately cease all link tuning. | |
410 | */ | |
411 | if (!test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags)) | |
412 | return; | |
413 | ||
414 | /* | |
415 | * Update statistics. | |
416 | */ | |
417 | rt2x00dev->ops->lib->link_stats(rt2x00dev, qual); | |
418 | rt2x00dev->low_level_stats.dot11FCSErrorCount += qual->rx_failed; | |
419 | ||
5352ff65 ID |
420 | /* |
421 | * Update quality RSSI for link tuning, | |
422 | * when we have received some frames and we managed to | |
423 | * collect the RSSI data we could use this. Otherwise we | |
424 | * must fallback to the default RSSI value. | |
425 | */ | |
426 | if (!link->avg_rssi || !qual->rx_success) | |
427 | qual->rssi = DEFAULT_RSSI; | |
428 | else | |
429 | qual->rssi = link->avg_rssi; | |
430 | ||
84e3196f ID |
431 | /* |
432 | * Only perform the link tuning when Link tuning | |
433 | * has been enabled (This could have been disabled from the EEPROM). | |
434 | */ | |
435 | if (!test_bit(CONFIG_DISABLE_LINK_TUNING, &rt2x00dev->flags)) | |
5352ff65 | 436 | rt2x00dev->ops->lib->link_tuner(rt2x00dev, qual, link->count); |
84e3196f ID |
437 | |
438 | /* | |
439 | * Precalculate a portion of the link signal which is | |
440 | * in based on the tx/rx success/failure counters. | |
441 | */ | |
442 | rt2x00link_precalculate_signal(rt2x00dev); | |
443 | ||
444 | /* | |
445 | * Send a signal to the led to update the led signal strength. | |
446 | */ | |
5352ff65 | 447 | rt2x00leds_led_quality(rt2x00dev, link->avg_rssi); |
84e3196f ID |
448 | |
449 | /* | |
450 | * Evaluate antenna setup, make this the last step since this could | |
451 | * possibly reset some statistics. | |
452 | */ | |
453 | rt2x00lib_antenna_diversity(rt2x00dev); | |
454 | ||
64abd803 ID |
455 | /* |
456 | * Reset the quality counters which recounted during each period. | |
457 | */ | |
458 | rt2x00link_reset_qual(rt2x00dev); | |
459 | ||
84e3196f ID |
460 | /* |
461 | * Increase tuner counter, and reschedule the next link tuner run. | |
462 | */ | |
5352ff65 | 463 | link->count++; |
84e3196f | 464 | queue_delayed_work(rt2x00dev->hw->workqueue, |
5352ff65 | 465 | &link->work, LINK_TUNE_INTERVAL); |
84e3196f ID |
466 | } |
467 | ||
468 | void rt2x00link_register(struct rt2x00_dev *rt2x00dev) | |
469 | { | |
470 | INIT_DELAYED_WORK(&rt2x00dev->link.work, rt2x00link_tuner); | |
471 | } |