LXR linux/drivers/net/wireless/ath/ath9k/dfs_pattern

   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 "ath9k.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 */
  36struct 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(PPB) ((PPB * MIN_PPB_THRESH + 50) / 100)
  45#define PRF2PRI(PRF) ((1000000 + PRF / 2) / PRF)
  46/* percentage of pulse width tolerance */
  47#define WIDTH_TOLERANCE 5
  48#define WIDTH_LOWER(X) ((X*(100-WIDTH_TOLERANCE)+50)/100)
  49#define WIDTH_UPPER(X) ((X*(100+WIDTH_TOLERANCE)+50)/100)
  50
  51#define ETSI_PATTERN(ID, WMIN, WMAX, PMIN, PMAX, PRF, PPB)      \
  52{                                                               \
  53        ID, WIDTH_LOWER(WMIN), WIDTH_UPPER(WMAX),               \
  54        (PRF2PRI(PMAX) - PRI_TOLERANCE),                        \
  55        (PRF2PRI(PMIN) * PRF + PRI_TOLERANCE), PRF, PPB * PRF,  \
  56        PPB_THRESH(PPB), PRI_TOLERANCE,                         \
  57}
  58
  59/* radar types as defined by ETSI EN-301-893 v1.5.1 */
  60static const struct radar_detector_specs etsi_radar_ref_types_v15[] = {
  61        ETSI_PATTERN(0,  0,  1,  700,  700, 1, 18),
  62        ETSI_PATTERN(1,  0,  5,  200, 1000, 1, 10),
  63        ETSI_PATTERN(2,  0, 15,  200, 1600, 1, 15),
  64        ETSI_PATTERN(3,  0, 15, 2300, 4000, 1, 25),
  65        ETSI_PATTERN(4, 20, 30, 2000, 4000, 1, 20),
  66        ETSI_PATTERN(5,  0,  2,  300,  400, 3, 10),
  67        ETSI_PATTERN(6,  0,  2,  400, 1200, 3, 15),
  68};
  69
  70static const struct radar_types etsi_radar_types_v15 = {
  71        .region                 = NL80211_DFS_ETSI,
  72        .num_radar_types        = ARRAY_SIZE(etsi_radar_ref_types_v15),
  73        .radar_types            = etsi_radar_ref_types_v15,
  74};
  75
  76/* for now, we support ETSI radar types, FCC and JP are TODO */
  77static const struct radar_types *dfs_domains[] = {
  78        &etsi_radar_types_v15,
  79};
  80
  81/**
  82 * get_dfs_domain_radar_types() - get radar types for a given DFS domain
  83 * @param domain DFS domain
  84 * @return radar_types ptr on success, NULL if DFS domain is not supported
  85 */
  86static const struct radar_types *
  87get_dfs_domain_radar_types(enum nl80211_dfs_regions region)
  88{
  89        u32 i;
  90        for (i = 0; i < ARRAY_SIZE(dfs_domains); i++) {
  91                if (dfs_domains[i]->region == region)
  92                        return dfs_domains[i];
  93        }
  94        return NULL;
  95}
  96
  97/**
  98 * struct channel_detector - detector elements for a DFS channel
  99 * @head: list_head
 100 * @freq: frequency for this channel detector in MHz
 101 * @detectors: array of dynamically created detector elements for this freq
 102 *
 103 * Channel detectors are required to provide multi-channel DFS detection, e.g.
 104 * to support off-channel scanning. A pattern detector has a list of channels
 105 * radar pulses have been reported for in the past.
 106 */
 107struct channel_detector {
 108        struct list_head head;
 109        u16 freq;
 110        struct pri_detector **detectors;
 111};
 112
 113/* channel_detector_reset() - reset detector lines for a given channel */
 114static void channel_detector_reset(struct dfs_pattern_detector *dpd,
 115                                   struct channel_detector *cd)
 116{
 117        u32 i;
 118        if (cd == NULL)
 119                return;
 120        for (i = 0; i < dpd->num_radar_types; i++)
 121                cd->detectors[i]->reset(cd->detectors[i], dpd->last_pulse_ts);
 122}
 123
 124/* channel_detector_exit() - destructor */
 125static void channel_detector_exit(struct dfs_pattern_detector *dpd,
 126                                  struct channel_detector *cd)
 127{
 128        u32 i;
 129        if (cd == NULL)
 130                return;
 131        list_del(&cd->head);
 132        for (i = 0; i < dpd->num_radar_types; i++) {
 133                struct pri_detector *de = cd->detectors[i];
 134                if (de != NULL)
 135                        de->exit(de);
 136        }
 137        kfree(cd->detectors);
 138        kfree(cd);
 139}
 140
 141static struct channel_detector *
 142channel_detector_create(struct dfs_pattern_detector *dpd, u16 freq)
 143{
 144        u32 sz, i;
 145        struct channel_detector *cd;
 146        struct ath_common *common = ath9k_hw_common(dpd->ah);
 147
 148        cd = kmalloc(sizeof(*cd), GFP_ATOMIC);
 149        if (cd == NULL)
 150                goto fail;
 151
 152        INIT_LIST_HEAD(&cd->head);
 153        cd->freq = freq;
 154        sz = sizeof(cd->detectors) * dpd->num_radar_types;
 155        cd->detectors = kzalloc(sz, GFP_ATOMIC);
 156        if (cd->detectors == NULL)
 157                goto fail;
 158
 159        for (i = 0; i < dpd->num_radar_types; i++) {
 160                const struct radar_detector_specs *rs = &dpd->radar_spec[i];
 161                struct pri_detector *de = pri_detector_init(rs);
 162                if (de == NULL)
 163                        goto fail;
 164                cd->detectors[i] = de;
 165        }
 166        list_add(&cd->head, &dpd->channel_detectors);
 167        return cd;
 168
 169fail:
 170        ath_dbg(common, DFS,
 171                "failed to allocate channel_detector for freq=%d\n", freq);
 172        channel_detector_exit(dpd, cd);
 173        return NULL;
 174}
 175
 176/**
 177 * channel_detector_get() - get channel detector for given frequency
 178 * @param dpd instance pointer
 179 * @param freq frequency in MHz
 180 * @return pointer to channel detector on success, NULL otherwise
 181 *
 182 * Return existing channel detector for the given frequency or return a
 183 * newly create one.
 184 */
 185static struct channel_detector *
 186channel_detector_get(struct dfs_pattern_detector *dpd, u16 freq)
 187{
 188        struct channel_detector *cd;
 189        list_for_each_entry(cd, &dpd->channel_detectors, head) {
 190                if (cd->freq == freq)
 191                        return cd;
 192        }
 193        return channel_detector_create(dpd, freq);
 194}
 195
 196/*
 197 * DFS Pattern Detector
 198 */
 199
 200/* dpd_reset(): reset all channel detectors */
 201static void dpd_reset(struct dfs_pattern_detector *dpd)
 202{
 203        struct channel_detector *cd;
 204        if (!list_empty(&dpd->channel_detectors))
 205                list_for_each_entry(cd, &dpd->channel_detectors, head)
 206                        channel_detector_reset(dpd, cd);
 207
 208}
 209static void dpd_exit(struct dfs_pattern_detector *dpd)
 210{
 211        struct channel_detector *cd, *cd0;
 212        if (!list_empty(&dpd->channel_detectors))
 213                list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
 214                        channel_detector_exit(dpd, cd);
 215        kfree(dpd);
 216}
 217
 218static bool
 219dpd_add_pulse(struct dfs_pattern_detector *dpd, struct pulse_event *event)
 220{
 221        u32 i;
 222        struct channel_detector *cd;
 223
 224        /*
 225         * pulses received for a non-supported or un-initialized
 226         * domain are treated as detected radars for fail-safety
 227         */
 228        if (dpd->region == NL80211_DFS_UNSET)
 229                return true;
 230
 231        cd = channel_detector_get(dpd, event->freq);
 232        if (cd == NULL)
 233                return false;
 234
 235        dpd->last_pulse_ts = event->ts;
 236        /* reset detector on time stamp wraparound, caused by TSF reset */
 237        if (event->ts < dpd->last_pulse_ts)
 238                dpd_reset(dpd);
 239
 240        /* do type individual pattern matching */
 241        for (i = 0; i < dpd->num_radar_types; i++) {
 242                struct pri_detector *pd = cd->detectors[i];
 243                struct pri_sequence *ps = pd->add_pulse(pd, event);
 244                if (ps != NULL) {
 245                        ath_dbg(ath9k_hw_common(dpd->ah), DFS,
 246                                "DFS: radar found on freq=%d: id=%d, pri=%d, "
 247                                "count=%d, count_false=%d\n",
 248                                event->freq, pd->rs->type_id,
 249                                ps->pri, ps->count, ps->count_falses);
 250                        channel_detector_reset(dpd, cd);
 251                        return true;
 252                }
 253        }
 254        return false;
 255}
 256
 257static bool dpd_set_domain(struct dfs_pattern_detector *dpd,
 258                           enum nl80211_dfs_regions region)
 259{
 260        const struct radar_types *rt;
 261        struct channel_detector *cd, *cd0;
 262
 263        if (dpd->region == region)
 264                return true;
 265
 266        dpd->region = NL80211_DFS_UNSET;
 267
 268        rt = get_dfs_domain_radar_types(region);
 269        if (rt == NULL)
 270                return false;
 271
 272        /* delete all channel detectors for previous DFS domain */
 273        if (!list_empty(&dpd->channel_detectors))
 274                list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
 275                        channel_detector_exit(dpd, cd);
 276        dpd->radar_spec = rt->radar_types;
 277        dpd->num_radar_types = rt->num_radar_types;
 278
 279        dpd->region = region;
 280        return true;
 281}
 282
 283static struct dfs_pattern_detector default_dpd = {
 284        .exit           = dpd_exit,
 285        .set_dfs_domain = dpd_set_domain,
 286        .add_pulse      = dpd_add_pulse,
 287        .region         = NL80211_DFS_UNSET,
 288};
 289
 290struct dfs_pattern_detector *
 291dfs_pattern_detector_init(struct ath_hw *ah, enum nl80211_dfs_regions region)
 292{
 293        struct dfs_pattern_detector *dpd;
 294        struct ath_common *common = ath9k_hw_common(ah);
 295
 296        dpd = kmalloc(sizeof(*dpd), GFP_KERNEL);
 297        if (dpd == NULL)
 298                return NULL;
 299
 300        *dpd = default_dpd;
 301        INIT_LIST_HEAD(&dpd->channel_detectors);
 302
 303        dpd->ah = ah;
 304        if (dpd->set_dfs_domain(dpd, region))
 305                return dpd;
 306
 307        ath_dbg(common, DFS,"Could not set DFS domain to %d", region);
 308        kfree(dpd);
 309        return NULL;
 310}
 311EXPORT_SYMBOL(dfs_pattern_detector_init);
 312