linux/drivers/net/wireless/ath/dfs_pattern_detector.c
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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        for (i = 0; i < dpd->num_radar_types; i++) {
 187                struct pri_detector *de = cd->detectors[i];
 188                if (de != NULL)
 189                        de->exit(de);
 190        }
 191        kfree(cd->detectors);
 192        kfree(cd);
 193}
 194
 195static struct channel_detector *
 196channel_detector_create(struct dfs_pattern_detector *dpd, u16 freq)
 197{
 198        u32 sz, i;
 199        struct channel_detector *cd;
 200
 201        cd = kmalloc(sizeof(*cd), GFP_ATOMIC);
 202        if (cd == NULL)
 203                goto fail;
 204
 205        INIT_LIST_HEAD(&cd->head);
 206        cd->freq = freq;
 207        sz = sizeof(cd->detectors) * dpd->num_radar_types;
 208        cd->detectors = kzalloc(sz, GFP_ATOMIC);
 209        if (cd->detectors == NULL)
 210                goto fail;
 211
 212        for (i = 0; i < dpd->num_radar_types; i++) {
 213                const struct radar_detector_specs *rs = &dpd->radar_spec[i];
 214                struct pri_detector *de = pri_detector_init(rs);
 215                if (de == NULL)
 216                        goto fail;
 217                cd->detectors[i] = de;
 218        }
 219        list_add(&cd->head, &dpd->channel_detectors);
 220        return cd;
 221
 222fail:
 223        ath_dbg(dpd->common, DFS,
 224                "failed to allocate channel_detector for freq=%d\n", freq);
 225        channel_detector_exit(dpd, cd);
 226        return NULL;
 227}
 228
 229/**
 230 * channel_detector_get() - get channel detector for given frequency
 231 * @dpd: DPD instance pointer
 232 * @freq: freq frequency in MHz
 233 *
 234 * Return value: pointer to channel detector on success, NULL otherwise
 235 *
 236 * Return existing channel detector for the given frequency or return a
 237 * newly create one.
 238 */
 239static struct channel_detector *
 240channel_detector_get(struct dfs_pattern_detector *dpd, u16 freq)
 241{
 242        struct channel_detector *cd;
 243        list_for_each_entry(cd, &dpd->channel_detectors, head) {
 244                if (cd->freq == freq)
 245                        return cd;
 246        }
 247        return channel_detector_create(dpd, freq);
 248}
 249
 250/*
 251 * DFS Pattern Detector
 252 */
 253
 254/* dpd_reset(): reset all channel detectors */
 255static void dpd_reset(struct dfs_pattern_detector *dpd)
 256{
 257        struct channel_detector *cd;
 258        list_for_each_entry(cd, &dpd->channel_detectors, head)
 259                channel_detector_reset(dpd, cd);
 260
 261}
 262static void dpd_exit(struct dfs_pattern_detector *dpd)
 263{
 264        struct channel_detector *cd, *cd0;
 265        list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
 266                channel_detector_exit(dpd, cd);
 267        kfree(dpd);
 268}
 269
 270static bool
 271dpd_add_pulse(struct dfs_pattern_detector *dpd, struct pulse_event *event,
 272              struct radar_detector_specs *rs)
 273{
 274        u32 i;
 275        struct channel_detector *cd;
 276
 277        /*
 278         * pulses received for a non-supported or un-initialized
 279         * domain are treated as detected radars for fail-safety
 280         */
 281        if (dpd->region == NL80211_DFS_UNSET)
 282                return true;
 283
 284        cd = channel_detector_get(dpd, event->freq);
 285        if (cd == NULL)
 286                return false;
 287
 288        /* reset detector on time stamp wraparound, caused by TSF reset */
 289        if (event->ts < dpd->last_pulse_ts)
 290                dpd_reset(dpd);
 291        dpd->last_pulse_ts = event->ts;
 292
 293        /* do type individual pattern matching */
 294        for (i = 0; i < dpd->num_radar_types; i++) {
 295                struct pri_detector *pd = cd->detectors[i];
 296                struct pri_sequence *ps = pd->add_pulse(pd, event);
 297                if (ps != NULL) {
 298                        if (rs != NULL)
 299                                memcpy(rs, pd->rs, sizeof(*rs));
 300                        ath_dbg(dpd->common, DFS,
 301                                "DFS: radar found on freq=%d: id=%d, pri=%d, "
 302                                "count=%d, count_false=%d\n",
 303                                event->freq, pd->rs->type_id,
 304                                ps->pri, ps->count, ps->count_falses);
 305                        pd->reset(pd, dpd->last_pulse_ts);
 306                        return true;
 307                }
 308        }
 309        return false;
 310}
 311
 312static struct ath_dfs_pool_stats
 313dpd_get_stats(struct dfs_pattern_detector *dpd)
 314{
 315        return global_dfs_pool_stats;
 316}
 317
 318static bool dpd_set_domain(struct dfs_pattern_detector *dpd,
 319                           enum nl80211_dfs_regions region)
 320{
 321        const struct radar_types *rt;
 322        struct channel_detector *cd, *cd0;
 323
 324        if (dpd->region == region)
 325                return true;
 326
 327        dpd->region = NL80211_DFS_UNSET;
 328
 329        rt = get_dfs_domain_radar_types(region);
 330        if (rt == NULL)
 331                return false;
 332
 333        /* delete all channel detectors for previous DFS domain */
 334        list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
 335                channel_detector_exit(dpd, cd);
 336        dpd->radar_spec = rt->radar_types;
 337        dpd->num_radar_types = rt->num_radar_types;
 338
 339        dpd->region = region;
 340        return true;
 341}
 342
 343static const struct dfs_pattern_detector default_dpd = {
 344        .exit           = dpd_exit,
 345        .set_dfs_domain = dpd_set_domain,
 346        .add_pulse      = dpd_add_pulse,
 347        .get_stats      = dpd_get_stats,
 348        .region         = NL80211_DFS_UNSET,
 349};
 350
 351struct dfs_pattern_detector *
 352dfs_pattern_detector_init(struct ath_common *common,
 353                          enum nl80211_dfs_regions region)
 354{
 355        struct dfs_pattern_detector *dpd;
 356
 357        if (!IS_ENABLED(CONFIG_CFG80211_CERTIFICATION_ONUS))
 358                return NULL;
 359
 360        dpd = kmalloc(sizeof(*dpd), GFP_KERNEL);
 361        if (dpd == NULL)
 362                return NULL;
 363
 364        *dpd = default_dpd;
 365        INIT_LIST_HEAD(&dpd->channel_detectors);
 366
 367        dpd->common = common;
 368        if (dpd->set_dfs_domain(dpd, region))
 369                return dpd;
 370
 371        ath_dbg(common, DFS,"Could not set DFS domain to %d", region);
 372        kfree(dpd);
 373        return NULL;
 374}
 375EXPORT_SYMBOL(dfs_pattern_detector_init);
 376