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  * @domain: DFS regulatory domain
  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, 1, 2, 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, false),
 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  * @param domain DFS domain
 137  * @return radar_types ptr on success, NULL if DFS domain is not supported
 138  */
 139 static const struct radar_types *
 140 get_dfs_domain_radar_types(enum nl80211_dfs_regions region)
 141 {
 142         u32 i;
 143         for (i = 0; i < ARRAY_SIZE(dfs_domains); i++) {
 144                 if (dfs_domains[i]->region == region)
 145                         return dfs_domains[i];
 146         }
 147         return NULL;
 148 }
 149
 150 /**
 151  * struct channel_detector - detector elements for a DFS channel
 152  * @head: list_head
 153  * @freq: frequency for this channel detector in MHz
 154  * @detectors: array of dynamically created detector elements for this freq
 155  *
 156  * Channel detectors are required to provide multi-channel DFS detection, e.g.
 157  * to support off-channel scanning. A pattern detector has a list of channels
 158  * radar pulses have been reported for in the past.
 159  */
 160 struct channel_detector {
 161         struct list_head head;
 162         u16 freq;
 163         struct pri_detector **detectors;
 164 };
 165
 166 /* channel_detector_reset() - reset detector lines for a given channel */
 167 static void channel_detector_reset(struct dfs_pattern_detector *dpd,
 168                                    struct channel_detector *cd)
 169 {
 170         u32 i;
 171         if (cd == NULL)
 172                 return;
 173         for (i = 0; i < dpd->num_radar_types; i++)
 174                 cd->detectors[i]->reset(cd->detectors[i], dpd->last_pulse_ts);
 175 }
 176
 177 /* channel_detector_exit() - destructor */
 178 static void channel_detector_exit(struct dfs_pattern_detector *dpd,
 179                                   struct channel_detector *cd)
 180 {
 181         u32 i;
 182         if (cd == NULL)
 183                 return;
 184         list_del(&cd->head);
 185         for (i = 0; i < dpd->num_radar_types; i++) {
 186                 struct pri_detector *de = cd->detectors[i];
 187                 if (de != NULL)
 188                         de->exit(de);
 189         }
 190         kfree(cd->detectors);
 191         kfree(cd);
 192 }
 193
 194 static struct channel_detector *
 195 channel_detector_create(struct dfs_pattern_detector *dpd, u16 freq)
 196 {
 197         u32 sz, i;
 198         struct channel_detector *cd;
 199
 200         cd = kmalloc(sizeof(*cd), GFP_ATOMIC);
 201         if (cd == NULL)
 202                 goto fail;
 203
 204         INIT_LIST_HEAD(&cd->head);
 205         cd->freq = freq;
 206         sz = sizeof(cd->detectors) * dpd->num_radar_types;
 207         cd->detectors = kzalloc(sz, GFP_ATOMIC);
 208         if (cd->detectors == NULL)
 209                 goto fail;
 210
 211         for (i = 0; i < dpd->num_radar_types; i++) {
 212                 const struct radar_detector_specs *rs = &dpd->radar_spec[i];
 213                 struct pri_detector *de = pri_detector_init(rs);
 214                 if (de == NULL)
 215                         goto fail;
 216                 cd->detectors[i] = de;
 217         }
 218         list_add(&cd->head, &dpd->channel_detectors);
 219         return cd;
 220
 221 fail:
 222         ath_dbg(dpd->common, DFS,
 223                 "failed to allocate channel_detector for freq=%d\n", freq);
 224         channel_detector_exit(dpd, cd);
 225         return NULL;
 226 }
 227
 228 /**
 229  * channel_detector_get() - get channel detector for given frequency
 230  * @param dpd instance pointer
 231  * @param freq frequency in MHz
 232  * @return pointer to channel detector on success, NULL otherwise
 233  *
 234  * Return existing channel detector for the given frequency or return a
 235  * newly create one.
 236  */
 237 static struct channel_detector *
 238 channel_detector_get(struct dfs_pattern_detector *dpd, u16 freq)
 239 {
 240         struct channel_detector *cd;
 241         list_for_each_entry(cd, &dpd->channel_detectors, head) {
 242                 if (cd->freq == freq)
 243                         return cd;
 244         }
 245         return channel_detector_create(dpd, freq);
 246 }
 247
 248 /*
 249  * DFS Pattern Detector
 250  */
 251
 252 /* dpd_reset(): reset all channel detectors */
 253 static void dpd_reset(struct dfs_pattern_detector *dpd)
 254 {
 255         struct channel_detector *cd;
 256         if (!list_empty(&dpd->channel_detectors))
 257                 list_for_each_entry(cd, &dpd->channel_detectors, head)
 258                         channel_detector_reset(dpd, cd);
 259
 260 }
 261 static void dpd_exit(struct dfs_pattern_detector *dpd)
 262 {
 263         struct channel_detector *cd, *cd0;
 264         if (!list_empty(&dpd->channel_detectors))
 265                 list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
 266                         channel_detector_exit(dpd, cd);
 267         kfree(dpd);
 268 }
 269
 270 static bool
 271 dpd_add_pulse(struct dfs_pattern_detector *dpd, struct pulse_event *event)
 272 {
 273         u32 i;
 274         struct channel_detector *cd;
 275
 276         /*
 277          * pulses received for a non-supported or un-initialized
 278          * domain are treated as detected radars for fail-safety
 279          */
 280         if (dpd->region == NL80211_DFS_UNSET)
 281                 return true;
 282
 283         cd = channel_detector_get(dpd, event->freq);
 284         if (cd == NULL)
 285                 return false;
 286
 287         /* reset detector on time stamp wraparound, caused by TSF reset */
 288         if (event->ts < dpd->last_pulse_ts)
 289                 dpd_reset(dpd);
 290         dpd->last_pulse_ts = event->ts;
 291
 292         /* do type individual pattern matching */
 293         for (i = 0; i < dpd->num_radar_types; i++) {
 294                 struct pri_detector *pd = cd->detectors[i];
 295                 struct pri_sequence *ps = pd->add_pulse(pd, event);
 296                 if (ps != NULL) {
 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         if (!list_empty(&dpd->channel_detectors))
 332                 list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
 333                         channel_detector_exit(dpd, cd);
 334         dpd->radar_spec = rt->radar_types;
 335         dpd->num_radar_types = rt->num_radar_types;
 336
 337         dpd->region = region;
 338         return true;
 339 }
 340
 341 static const struct dfs_pattern_detector default_dpd = {
 342         .exit           = dpd_exit,
 343         .set_dfs_domain = dpd_set_domain,
 344         .add_pulse      = dpd_add_pulse,
 345         .get_stats      = dpd_get_stats,
 346         .region         = NL80211_DFS_UNSET,
 347 };
 348
 349 struct dfs_pattern_detector *
 350 dfs_pattern_detector_init(struct ath_common *common,
 351                           enum nl80211_dfs_regions region)
 352 {
 353         struct dfs_pattern_detector *dpd;
 354
 355         if (!IS_ENABLED(CONFIG_CFG80211_CERTIFICATION_ONUS))
 356                 return NULL;
 357
 358         dpd = kmalloc(sizeof(*dpd), GFP_KERNEL);
 359         if (dpd == NULL)
 360                 return NULL;
 361
 362         *dpd = default_dpd;
 363         INIT_LIST_HEAD(&dpd->channel_detectors);
 364
 365         dpd->common = common;
 366         if (dpd->set_dfs_domain(dpd, region))
 367                 return dpd;
 368
 369         ath_dbg(common, DFS,"Could not set DFS domain to %d", region);
 370         kfree(dpd);
 371         return NULL;
 372 }
 373 EXPORT_SYMBOL(dfs_pattern_detector_init);