drivers/net/wireless/ath/dfs_pattern_detector.c

   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  */
  30 struct 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 */
  55 static 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
  65 static 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  */
  85 static 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
  97 static 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 }
 110 static 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
 122 static 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
 128 static 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  */
 140 static const struct radar_types *
 141 get_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  */
 161 struct 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 */
 168 static 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 */
 179 static 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
 196 static struct channel_detector *
 197 channel_detector_create(struct dfs_pattern_detector *dpd, u16 freq)
 198 {
 199         u32 i;
 200         struct channel_detector *cd;
 201
 202         cd = kzalloc(struct_size(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
 219 fail:
 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  */
 236 static struct channel_detector *
 237 channel_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 */
 252 static 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 }
 259 static 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
 267 static bool
 268 dpd_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
 309 static struct ath_dfs_pool_stats
 310 dpd_get_stats(struct dfs_pattern_detector *dpd)
 311 {
 312         return global_dfs_pool_stats;
 313 }
 314
 315 static 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
 340 static 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
 348 struct dfs_pattern_detector *
 349 dfs_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(sizeof(*dpd), GFP_KERNEL);
 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 }
 372 EXPORT_SYMBOL(dfs_pattern_detector_init);