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1/*
2 * Copyright (c) 2012 Neratec Solutions AG
3 *
4 * Permission to use, copy, modify, and/or distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 */
16
17#include <linux/slab.h>
18#include <linux/export.h>
19
20#include "dfs_pattern_detector.h"
21#include "dfs_pri_detector.h"
22#include "ath.h"
23
24/**
25 * struct radar_types - contains array of patterns defined for one DFS domain
26 * @region: regulatory DFS region
27 * @num_radar_types: number of radar types to follow
28 * @radar_types: radar types array
29 */
30struct radar_types {
31 enum nl80211_dfs_regions region;
32 u32 num_radar_types;
33 const struct radar_detector_specs *radar_types;
34};
35
36/* percentage on ppb threshold to trigger detection */
37#define MIN_PPB_THRESH 50
38#define PPB_THRESH_RATE(PPB, RATE) ((PPB * RATE + 100 - RATE) / 100)
39#define PPB_THRESH(PPB) PPB_THRESH_RATE(PPB, MIN_PPB_THRESH)
40#define PRF2PRI(PRF) ((1000000 + PRF / 2) / PRF)
41/* percentage of pulse width tolerance */
42#define WIDTH_TOLERANCE 5
43#define WIDTH_LOWER(X) ((X*(100-WIDTH_TOLERANCE)+50)/100)
44#define WIDTH_UPPER(X) ((X*(100+WIDTH_TOLERANCE)+50)/100)
45
46#define ETSI_PATTERN(ID, WMIN, WMAX, PMIN, PMAX, PRF, PPB, CHIRP) \
47{ \
48 ID, WIDTH_LOWER(WMIN), WIDTH_UPPER(WMAX), \
49 (PRF2PRI(PMAX) - PRI_TOLERANCE), \
50 (PRF2PRI(PMIN) * PRF + PRI_TOLERANCE), PRF, PPB * PRF, \
51 PPB_THRESH(PPB), PRI_TOLERANCE, CHIRP \
52}
53
54/* radar types as defined by ETSI EN-301-893 v1.5.1 */
55static const struct radar_detector_specs etsi_radar_ref_types_v15[] = {
56 ETSI_PATTERN(0, 0, 1, 700, 700, 1, 18, false),
57 ETSI_PATTERN(1, 0, 5, 200, 1000, 1, 10, false),
58 ETSI_PATTERN(2, 0, 15, 200, 1600, 1, 15, false),
59 ETSI_PATTERN(3, 0, 15, 2300, 4000, 1, 25, false),
60 ETSI_PATTERN(4, 20, 30, 2000, 4000, 1, 20, false),
61 ETSI_PATTERN(5, 0, 2, 300, 400, 3, 10, false),
62 ETSI_PATTERN(6, 0, 2, 400, 1200, 3, 15, false),
63};
64
65static const struct radar_types etsi_radar_types_v15 = {
66 .region = NL80211_DFS_ETSI,
67 .num_radar_types = ARRAY_SIZE(etsi_radar_ref_types_v15),
68 .radar_types = etsi_radar_ref_types_v15,
69};
70
71#define FCC_PATTERN(ID, WMIN, WMAX, PMIN, PMAX, PRF, PPB, CHIRP) \
72{ \
73 ID, WIDTH_LOWER(WMIN), WIDTH_UPPER(WMAX), \
74 PMIN - PRI_TOLERANCE, \
75 PMAX * PRF + PRI_TOLERANCE, PRF, PPB * PRF, \
76 PPB_THRESH(PPB), PRI_TOLERANCE, CHIRP \
77}
78
79/* radar types released on August 14, 2014
80 * type 1 PRI values randomly selected within the range of 518 and 3066.
81 * divide it to 3 groups is good enough for both of radar detection and
82 * avoiding false detection based on practical test results
83 * collected for more than a year.
84 */
85static const struct radar_detector_specs fcc_radar_ref_types[] = {
86 FCC_PATTERN(0, 0, 1, 1428, 1428, 1, 18, false),
87 FCC_PATTERN(101, 0, 1, 518, 938, 1, 57, false),
88 FCC_PATTERN(102, 0, 1, 938, 2000, 1, 27, false),
89 FCC_PATTERN(103, 0, 1, 2000, 3066, 1, 18, false),
90 FCC_PATTERN(2, 0, 5, 150, 230, 1, 23, false),
91 FCC_PATTERN(3, 6, 10, 200, 500, 1, 16, false),
92 FCC_PATTERN(4, 11, 20, 200, 500, 1, 12, false),
93 FCC_PATTERN(5, 50, 100, 1000, 2000, 1, 1, true),
94 FCC_PATTERN(6, 0, 1, 333, 333, 1, 9, false),
95};
96
97static const struct radar_types fcc_radar_types = {
98 .region = NL80211_DFS_FCC,
99 .num_radar_types = ARRAY_SIZE(fcc_radar_ref_types),
100 .radar_types = fcc_radar_ref_types,
101};
102
103#define JP_PATTERN(ID, WMIN, WMAX, PMIN, PMAX, PRF, PPB, RATE, CHIRP) \
104{ \
105 ID, WIDTH_LOWER(WMIN), WIDTH_UPPER(WMAX), \
106 PMIN - PRI_TOLERANCE, \
107 PMAX * PRF + PRI_TOLERANCE, PRF, PPB * PRF, \
108 PPB_THRESH_RATE(PPB, RATE), PRI_TOLERANCE, CHIRP \
109}
110static const struct radar_detector_specs jp_radar_ref_types[] = {
111 JP_PATTERN(0, 0, 1, 1428, 1428, 1, 18, 29, false),
112 JP_PATTERN(1, 2, 3, 3846, 3846, 1, 18, 29, false),
113 JP_PATTERN(2, 0, 1, 1388, 1388, 1, 18, 50, false),
114 JP_PATTERN(3, 0, 4, 4000, 4000, 1, 18, 50, false),
115 JP_PATTERN(4, 0, 5, 150, 230, 1, 23, 50, false),
116 JP_PATTERN(5, 6, 10, 200, 500, 1, 16, 50, false),
117 JP_PATTERN(6, 11, 20, 200, 500, 1, 12, 50, false),
118 JP_PATTERN(7, 50, 100, 1000, 2000, 1, 3, 50, true),
119 JP_PATTERN(5, 0, 1, 333, 333, 1, 9, 50, false),
120};
121
122static const struct radar_types jp_radar_types = {
123 .region = NL80211_DFS_JP,
124 .num_radar_types = ARRAY_SIZE(jp_radar_ref_types),
125 .radar_types = jp_radar_ref_types,
126};
127
128static const struct radar_types *dfs_domains[] = {
129 &etsi_radar_types_v15,
130 &fcc_radar_types,
131 &jp_radar_types,
132};
133
134/**
135 * get_dfs_domain_radar_types() - get radar types for a given DFS domain
136 * @region: regulatory DFS region
137 *
138 * Return value: radar_types ptr on success, NULL if DFS domain is not supported
139 */
140static const struct radar_types *
141get_dfs_domain_radar_types(enum nl80211_dfs_regions region)
142{
143 u32 i;
144 for (i = 0; i < ARRAY_SIZE(dfs_domains); i++) {
145 if (dfs_domains[i]->region == region)
146 return dfs_domains[i];
147 }
148 return NULL;
149}
150
151/**
152 * struct channel_detector - detector elements for a DFS channel
153 * @head: list_head
154 * @freq: frequency for this channel detector in MHz
155 * @detectors: array of dynamically created detector elements for this freq
156 *
157 * Channel detectors are required to provide multi-channel DFS detection, e.g.
158 * to support off-channel scanning. A pattern detector has a list of channels
159 * radar pulses have been reported for in the past.
160 */
161struct channel_detector {
162 struct list_head head;
163 u16 freq;
164 struct pri_detector *detectors[];
165};
166
167/* channel_detector_reset() - reset detector lines for a given channel */
168static void channel_detector_reset(struct dfs_pattern_detector *dpd,
169 struct channel_detector *cd)
170{
171 u32 i;
172 if (cd == NULL)
173 return;
174 for (i = 0; i < dpd->num_radar_types; i++)
175 cd->detectors[i]->reset(cd->detectors[i], dpd->last_pulse_ts);
176}
177
178/* channel_detector_exit() - destructor */
179static void channel_detector_exit(struct dfs_pattern_detector *dpd,
180 struct channel_detector *cd)
181{
182 u32 i;
183 if (cd == NULL)
184 return;
185 list_del(&cd->head);
186
187 for (i = 0; i < dpd->num_radar_types; i++) {
188 struct pri_detector *de = cd->detectors[i];
189 if (de != NULL)
190 de->exit(de);
191 }
192
193 kfree(cd);
194}
195
196static struct channel_detector *
197channel_detector_create(struct dfs_pattern_detector *dpd, u16 freq)
198{
199 u32 i;
200 struct channel_detector *cd;
201
202 cd = kzalloc_flex(*cd, detectors, dpd->num_radar_types, GFP_ATOMIC);
203 if (cd == NULL)
204 goto fail;
205
206 INIT_LIST_HEAD(&cd->head);
207 cd->freq = freq;
208
209 for (i = 0; i < dpd->num_radar_types; i++) {
210 const struct radar_detector_specs *rs = &dpd->radar_spec[i];
211 struct pri_detector *de = pri_detector_init(rs);
212 if (de == NULL)
213 goto fail;
214 cd->detectors[i] = de;
215 }
216 list_add(&cd->head, &dpd->channel_detectors);
217 return cd;
218
219fail:
220 ath_dbg(dpd->common, DFS,
221 "failed to allocate channel_detector for freq=%d\n", freq);
222 channel_detector_exit(dpd, cd);
223 return NULL;
224}
225
226/**
227 * channel_detector_get() - get channel detector for given frequency
228 * @dpd: DPD instance pointer
229 * @freq: freq frequency in MHz
230 *
231 * Return value: pointer to channel detector on success, NULL otherwise
232 *
233 * Return existing channel detector for the given frequency or return a
234 * newly create one.
235 */
236static struct channel_detector *
237channel_detector_get(struct dfs_pattern_detector *dpd, u16 freq)
238{
239 struct channel_detector *cd;
240 list_for_each_entry(cd, &dpd->channel_detectors, head) {
241 if (cd->freq == freq)
242 return cd;
243 }
244 return channel_detector_create(dpd, freq);
245}
246
247/*
248 * DFS Pattern Detector
249 */
250
251/* dpd_reset(): reset all channel detectors */
252static void dpd_reset(struct dfs_pattern_detector *dpd)
253{
254 struct channel_detector *cd;
255 list_for_each_entry(cd, &dpd->channel_detectors, head)
256 channel_detector_reset(dpd, cd);
257
258}
259static void dpd_exit(struct dfs_pattern_detector *dpd)
260{
261 struct channel_detector *cd, *cd0;
262 list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
263 channel_detector_exit(dpd, cd);
264 kfree(dpd);
265}
266
267static bool
268dpd_add_pulse(struct dfs_pattern_detector *dpd, struct pulse_event *event,
269 struct radar_detector_specs *rs)
270{
271 u32 i;
272 struct channel_detector *cd;
273
274 /*
275 * pulses received for a non-supported or un-initialized
276 * domain are treated as detected radars for fail-safety
277 */
278 if (dpd->region == NL80211_DFS_UNSET)
279 return true;
280
281 cd = channel_detector_get(dpd, event->freq);
282 if (cd == NULL)
283 return false;
284
285 /* reset detector on time stamp wraparound, caused by TSF reset */
286 if (event->ts < dpd->last_pulse_ts)
287 dpd_reset(dpd);
288 dpd->last_pulse_ts = event->ts;
289
290 /* do type individual pattern matching */
291 for (i = 0; i < dpd->num_radar_types; i++) {
292 struct pri_detector *pd = cd->detectors[i];
293 struct pri_sequence *ps = pd->add_pulse(pd, event);
294 if (ps != NULL) {
295 if (rs != NULL)
296 memcpy(rs, pd->rs, sizeof(*rs));
297 ath_dbg(dpd->common, DFS,
298 "DFS: radar found on freq=%d: id=%d, pri=%d, "
299 "count=%d, count_false=%d\n",
300 event->freq, pd->rs->type_id,
301 ps->pri, ps->count, ps->count_falses);
302 pd->reset(pd, dpd->last_pulse_ts);
303 return true;
304 }
305 }
306 return false;
307}
308
309static struct ath_dfs_pool_stats
310dpd_get_stats(struct dfs_pattern_detector *dpd)
311{
312 return global_dfs_pool_stats;
313}
314
315static bool dpd_set_domain(struct dfs_pattern_detector *dpd,
316 enum nl80211_dfs_regions region)
317{
318 const struct radar_types *rt;
319 struct channel_detector *cd, *cd0;
320
321 if (dpd->region == region)
322 return true;
323
324 dpd->region = NL80211_DFS_UNSET;
325
326 rt = get_dfs_domain_radar_types(region);
327 if (rt == NULL)
328 return false;
329
330 /* delete all channel detectors for previous DFS domain */
331 list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
332 channel_detector_exit(dpd, cd);
333 dpd->radar_spec = rt->radar_types;
334 dpd->num_radar_types = rt->num_radar_types;
335
336 dpd->region = region;
337 return true;
338}
339
340static const struct dfs_pattern_detector default_dpd = {
341 .exit = dpd_exit,
342 .set_dfs_domain = dpd_set_domain,
343 .add_pulse = dpd_add_pulse,
344 .get_stats = dpd_get_stats,
345 .region = NL80211_DFS_UNSET,
346};
347
348struct dfs_pattern_detector *
349dfs_pattern_detector_init(struct ath_common *common,
350 enum nl80211_dfs_regions region)
351{
352 struct dfs_pattern_detector *dpd;
353
354 if (!IS_ENABLED(CONFIG_CFG80211_CERTIFICATION_ONUS))
355 return NULL;
356
357 dpd = kmalloc_obj(*dpd);
358 if (dpd == NULL)
359 return NULL;
360
361 *dpd = default_dpd;
362 INIT_LIST_HEAD(&dpd->channel_detectors);
363
364 dpd->common = common;
365 if (dpd->set_dfs_domain(dpd, region))
366 return dpd;
367
368 ath_dbg(common, DFS,"Could not set DFS domain to %d", region);
369 kfree(dpd);
370 return NULL;
371}
372EXPORT_SYMBOL(dfs_pattern_detector_init);