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  * tolerated deviation of radar time stamp in usecs on both sides
  26  * TODO: this might need to be HW-dependent
  27  */
  28 #define PRI_TOLERANCE   16
  29
  30 /**
  31  * struct radar_types - contains array of patterns defined for one DFS domain
  32  * @domain: DFS regulatory domain
  33  * @num_radar_types: number of radar types to follow
  34  * @radar_types: radar types array
  35  */
  36 struct radar_types {
  37         enum nl80211_dfs_regions region;
  38         u32 num_radar_types;
  39         const struct radar_detector_specs *radar_types;
  40 };
  41
  42 /* percentage on ppb threshold to trigger detection */
  43 #define MIN_PPB_THRESH  50
  44 #define PPB_THRESH_RATE(PPB, RATE) ((PPB * RATE + 100 - RATE) / 100)
  45 #define PPB_THRESH(PPB) PPB_THRESH_RATE(PPB, MIN_PPB_THRESH)
  46 #define PRF2PRI(PRF) ((1000000 + PRF / 2) / PRF)
  47 /* percentage of pulse width tolerance */
  48 #define WIDTH_TOLERANCE 5
  49 #define WIDTH_LOWER(X) ((X*(100-WIDTH_TOLERANCE)+50)/100)
  50 #define WIDTH_UPPER(X) ((X*(100+WIDTH_TOLERANCE)+50)/100)
  51
  52 #define ETSI_PATTERN(ID, WMIN, WMAX, PMIN, PMAX, PRF, PPB, CHIRP)       \
  53 {                                                               \
  54         ID, WIDTH_LOWER(WMIN), WIDTH_UPPER(WMAX),               \
  55         (PRF2PRI(PMAX) - PRI_TOLERANCE),                        \
  56         (PRF2PRI(PMIN) * PRF + PRI_TOLERANCE), PRF, PPB * PRF,  \
  57         PPB_THRESH(PPB), PRI_TOLERANCE, CHIRP                   \
  58 }
  59
  60 /* radar types as defined by ETSI EN-301-893 v1.5.1 */
  61 static const struct radar_detector_specs etsi_radar_ref_types_v15[] = {
  62         ETSI_PATTERN(0,  0,  1,  700,  700, 1, 18, false),
  63         ETSI_PATTERN(1,  0,  5,  200, 1000, 1, 10, false),
  64         ETSI_PATTERN(2,  0, 15,  200, 1600, 1, 15, false),
  65         ETSI_PATTERN(3,  0, 15, 2300, 4000, 1, 25, false),
  66         ETSI_PATTERN(4, 20, 30, 2000, 4000, 1, 20, false),
  67         ETSI_PATTERN(5,  0,  2,  300,  400, 3, 10, false),
  68         ETSI_PATTERN(6,  0,  2,  400, 1200, 3, 15, false),
  69 };
  70
  71 static const struct radar_types etsi_radar_types_v15 = {
  72         .region                 = NL80211_DFS_ETSI,
  73         .num_radar_types        = ARRAY_SIZE(etsi_radar_ref_types_v15),
  74         .radar_types            = etsi_radar_ref_types_v15,
  75 };
  76
  77 #define FCC_PATTERN(ID, WMIN, WMAX, PMIN, PMAX, PRF, PPB, CHIRP)        \
  78 {                                                               \
  79         ID, WIDTH_LOWER(WMIN), WIDTH_UPPER(WMAX),               \
  80         PMIN - PRI_TOLERANCE,                                   \
  81         PMAX * PRF + PRI_TOLERANCE, PRF, PPB * PRF,             \
  82         PPB_THRESH(PPB), PRI_TOLERANCE, CHIRP                   \
  83 }
  84
  85 /* radar types released on August 14, 2014
  86  * type 1 PRI values randomly selected within the range of 518 and 3066.
  87  * divide it to 3 groups is good enough for both of radar detection and
  88  * avoiding false detection based on practical test results
  89  * collected for more than a year.
  90  */
  91 static const struct radar_detector_specs fcc_radar_ref_types[] = {
  92         FCC_PATTERN(0, 0, 1, 1428, 1428, 1, 18, false),
  93         FCC_PATTERN(101, 0, 1, 518, 938, 1, 57, false),
  94         FCC_PATTERN(102, 0, 1, 938, 2000, 1, 27, false),
  95         FCC_PATTERN(103, 0, 1, 2000, 3066, 1, 18, false),
  96         FCC_PATTERN(2, 0, 5, 150, 230, 1, 23, false),
  97         FCC_PATTERN(3, 6, 10, 200, 500, 1, 16, false),
  98         FCC_PATTERN(4, 11, 20, 200, 500, 1, 12, false),
  99         FCC_PATTERN(5, 50, 100, 1000, 2000, 1, 1, true),
 100         FCC_PATTERN(6, 0, 1, 333, 333, 1, 9, false),
 101 };
 102
 103 static const struct radar_types fcc_radar_types = {
 104         .region                 = NL80211_DFS_FCC,
 105         .num_radar_types        = ARRAY_SIZE(fcc_radar_ref_types),
 106         .radar_types            = fcc_radar_ref_types,
 107 };
 108
 109 #define JP_PATTERN(ID, WMIN, WMAX, PMIN, PMAX, PRF, PPB, RATE, CHIRP)   \
 110 {                                                               \
 111         ID, WIDTH_LOWER(WMIN), WIDTH_UPPER(WMAX),               \
 112         PMIN - PRI_TOLERANCE,                                   \
 113         PMAX * PRF + PRI_TOLERANCE, PRF, PPB * PRF,             \
 114         PPB_THRESH_RATE(PPB, RATE), PRI_TOLERANCE, CHIRP        \
 115 }
 116 static const struct radar_detector_specs jp_radar_ref_types[] = {
 117         JP_PATTERN(0, 0, 1, 1428, 1428, 1, 18, 29, false),
 118         JP_PATTERN(1, 2, 3, 3846, 3846, 1, 18, 29, false),
 119         JP_PATTERN(2, 0, 1, 1388, 1388, 1, 18, 50, false),
 120         JP_PATTERN(3, 1, 2, 4000, 4000, 1, 18, 50, false),
 121         JP_PATTERN(4, 0, 5, 150, 230, 1, 23, 50, false),
 122         JP_PATTERN(5, 6, 10, 200, 500, 1, 16, 50, false),
 123         JP_PATTERN(6, 11, 20, 200, 500, 1, 12, 50, false),
 124         JP_PATTERN(7, 50, 100, 1000, 2000, 1, 20, 50, false),
 125         JP_PATTERN(5, 0, 1, 333, 333, 1, 9, 50, false),
 126 };
 127
 128 static const struct radar_types jp_radar_types = {
 129         .region                 = NL80211_DFS_JP,
 130         .num_radar_types        = ARRAY_SIZE(jp_radar_ref_types),
 131         .radar_types            = jp_radar_ref_types,
 132 };
 133
 134 static const struct radar_types *dfs_domains[] = {
 135         &etsi_radar_types_v15,
 136         &fcc_radar_types,
 137         &jp_radar_types,
 138 };
 139
 140 /**
 141  * get_dfs_domain_radar_types() - get radar types for a given DFS domain
 142  * @param domain DFS domain
 143  * @return radar_types ptr on success, NULL if DFS domain is not supported
 144  */
 145 static const struct radar_types *
 146 get_dfs_domain_radar_types(enum nl80211_dfs_regions region)
 147 {
 148         u32 i;
 149         for (i = 0; i < ARRAY_SIZE(dfs_domains); i++) {
 150                 if (dfs_domains[i]->region == region)
 151                         return dfs_domains[i];
 152         }
 153         return NULL;
 154 }
 155
 156 /**
 157  * struct channel_detector - detector elements for a DFS channel
 158  * @head: list_head
 159  * @freq: frequency for this channel detector in MHz
 160  * @detectors: array of dynamically created detector elements for this freq
 161  *
 162  * Channel detectors are required to provide multi-channel DFS detection, e.g.
 163  * to support off-channel scanning. A pattern detector has a list of channels
 164  * radar pulses have been reported for in the past.
 165  */
 166 struct channel_detector {
 167         struct list_head head;
 168         u16 freq;
 169         struct pri_detector **detectors;
 170 };
 171
 172 /* channel_detector_reset() - reset detector lines for a given channel */
 173 static void channel_detector_reset(struct dfs_pattern_detector *dpd,
 174                                    struct channel_detector *cd)
 175 {
 176         u32 i;
 177         if (cd == NULL)
 178                 return;
 179         for (i = 0; i < dpd->num_radar_types; i++)
 180                 cd->detectors[i]->reset(cd->detectors[i], dpd->last_pulse_ts);
 181 }
 182
 183 /* channel_detector_exit() - destructor */
 184 static void channel_detector_exit(struct dfs_pattern_detector *dpd,
 185                                   struct channel_detector *cd)
 186 {
 187         u32 i;
 188         if (cd == NULL)
 189                 return;
 190         list_del(&cd->head);
 191         for (i = 0; i < dpd->num_radar_types; i++) {
 192                 struct pri_detector *de = cd->detectors[i];
 193                 if (de != NULL)
 194                         de->exit(de);
 195         }
 196         kfree(cd->detectors);
 197         kfree(cd);
 198 }
 199
 200 static struct channel_detector *
 201 channel_detector_create(struct dfs_pattern_detector *dpd, u16 freq)
 202 {
 203         u32 sz, i;
 204         struct channel_detector *cd;
 205
 206         cd = kmalloc(sizeof(*cd), GFP_ATOMIC);
 207         if (cd == NULL)
 208                 goto fail;
 209
 210         INIT_LIST_HEAD(&cd->head);
 211         cd->freq = freq;
 212         sz = sizeof(cd->detectors) * dpd->num_radar_types;
 213         cd->detectors = kzalloc(sz, GFP_ATOMIC);
 214         if (cd->detectors == NULL)
 215                 goto fail;
 216
 217         for (i = 0; i < dpd->num_radar_types; i++) {
 218                 const struct radar_detector_specs *rs = &dpd->radar_spec[i];
 219                 struct pri_detector *de = pri_detector_init(rs);
 220                 if (de == NULL)
 221                         goto fail;
 222                 cd->detectors[i] = de;
 223         }
 224         list_add(&cd->head, &dpd->channel_detectors);
 225         return cd;
 226
 227 fail:
 228         ath_dbg(dpd->common, DFS,
 229                 "failed to allocate channel_detector for freq=%d\n", freq);
 230         channel_detector_exit(dpd, cd);
 231         return NULL;
 232 }
 233
 234 /**
 235  * channel_detector_get() - get channel detector for given frequency
 236  * @param dpd instance pointer
 237  * @param freq frequency in MHz
 238  * @return pointer to channel detector on success, NULL otherwise
 239  *
 240  * Return existing channel detector for the given frequency or return a
 241  * newly create one.
 242  */
 243 static struct channel_detector *
 244 channel_detector_get(struct dfs_pattern_detector *dpd, u16 freq)
 245 {
 246         struct channel_detector *cd;
 247         list_for_each_entry(cd, &dpd->channel_detectors, head) {
 248                 if (cd->freq == freq)
 249                         return cd;
 250         }
 251         return channel_detector_create(dpd, freq);
 252 }
 253
 254 /*
 255  * DFS Pattern Detector
 256  */
 257
 258 /* dpd_reset(): reset all channel detectors */
 259 static void dpd_reset(struct dfs_pattern_detector *dpd)
 260 {
 261         struct channel_detector *cd;
 262         if (!list_empty(&dpd->channel_detectors))
 263                 list_for_each_entry(cd, &dpd->channel_detectors, head)
 264                         channel_detector_reset(dpd, cd);
 265
 266 }
 267 static void dpd_exit(struct dfs_pattern_detector *dpd)
 268 {
 269         struct channel_detector *cd, *cd0;
 270         if (!list_empty(&dpd->channel_detectors))
 271                 list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
 272                         channel_detector_exit(dpd, cd);
 273         kfree(dpd);
 274 }
 275
 276 static bool
 277 dpd_add_pulse(struct dfs_pattern_detector *dpd, struct pulse_event *event)
 278 {
 279         u32 i;
 280         struct channel_detector *cd;
 281
 282         /*
 283          * pulses received for a non-supported or un-initialized
 284          * domain are treated as detected radars for fail-safety
 285          */
 286         if (dpd->region == NL80211_DFS_UNSET)
 287                 return true;
 288
 289         cd = channel_detector_get(dpd, event->freq);
 290         if (cd == NULL)
 291                 return false;
 292
 293         dpd->last_pulse_ts = event->ts;
 294         /* reset detector on time stamp wraparound, caused by TSF reset */
 295         if (event->ts < dpd->last_pulse_ts)
 296                 dpd_reset(dpd);
 297
 298         /* do type individual pattern matching */
 299         for (i = 0; i < dpd->num_radar_types; i++) {
 300                 struct pri_detector *pd = cd->detectors[i];
 301                 struct pri_sequence *ps = pd->add_pulse(pd, event);
 302                 if (ps != NULL) {
 303                         ath_dbg(dpd->common, DFS,
 304                                 "DFS: radar found on freq=%d: id=%d, pri=%d, "
 305                                 "count=%d, count_false=%d\n",
 306                                 event->freq, pd->rs->type_id,
 307                                 ps->pri, ps->count, ps->count_falses);
 308                         pd->reset(pd, dpd->last_pulse_ts);
 309                         return true;
 310                 }
 311         }
 312         return false;
 313 }
 314
 315 static struct ath_dfs_pool_stats
 316 dpd_get_stats(struct dfs_pattern_detector *dpd)
 317 {
 318         return global_dfs_pool_stats;
 319 }
 320
 321 static bool dpd_set_domain(struct dfs_pattern_detector *dpd,
 322                            enum nl80211_dfs_regions region)
 323 {
 324         const struct radar_types *rt;
 325         struct channel_detector *cd, *cd0;
 326
 327         if (dpd->region == region)
 328                 return true;
 329
 330         dpd->region = NL80211_DFS_UNSET;
 331
 332         rt = get_dfs_domain_radar_types(region);
 333         if (rt == NULL)
 334                 return false;
 335
 336         /* delete all channel detectors for previous DFS domain */
 337         if (!list_empty(&dpd->channel_detectors))
 338                 list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
 339                         channel_detector_exit(dpd, cd);
 340         dpd->radar_spec = rt->radar_types;
 341         dpd->num_radar_types = rt->num_radar_types;
 342
 343         dpd->region = region;
 344         return true;
 345 }
 346
 347 static struct dfs_pattern_detector default_dpd = {
 348         .exit           = dpd_exit,
 349         .set_dfs_domain = dpd_set_domain,
 350         .add_pulse      = dpd_add_pulse,
 351         .get_stats      = dpd_get_stats,
 352         .region         = NL80211_DFS_UNSET,
 353 };
 354
 355 struct dfs_pattern_detector *
 356 dfs_pattern_detector_init(struct ath_common *common,
 357                           enum nl80211_dfs_regions region)
 358 {
 359         struct dfs_pattern_detector *dpd;
 360
 361         if (!config_enabled(CONFIG_CFG80211_CERTIFICATION_ONUS))
 362                 return NULL;
 363
 364         dpd = kmalloc(sizeof(*dpd), GFP_KERNEL);
 365         if (dpd == NULL)
 366                 return NULL;
 367
 368         *dpd = default_dpd;
 369         INIT_LIST_HEAD(&dpd->channel_detectors);
 370
 371         dpd->common = common;
 372         if (dpd->set_dfs_domain(dpd, region))
 373                 return dpd;
 374
 375         ath_dbg(common, DFS,"Could not set DFS domain to %d", region);
 376         kfree(dpd);
 377         return NULL;
 378 }
 379 EXPORT_SYMBOL(dfs_pattern_detector_init);