drivers/net/wireless/ath/ath9k/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
  23 /*
  24  * tolerated deviation of radar time stamp in usecs on both sides
  25  * TODO: this might need to be HW-dependent
  26  */
  27 #define PRI_TOLERANCE   16
  28
  29 /**
  30  * struct radar_types - contains array of patterns defined for one DFS domain
  31  * @domain: DFS regulatory domain
  32  * @num_radar_types: number of radar types to follow
  33  * @radar_types: radar types array
  34  */
  35 struct radar_types {
  36         enum nl80211_dfs_regions region;
  37         u32 num_radar_types;
  38         const struct radar_detector_specs *radar_types;
  39 };
  40
  41 /* percentage on ppb threshold to trigger detection */
  42 #define MIN_PPB_THRESH  50
  43 #define PPB_THRESH(PPB) ((PPB * MIN_PPB_THRESH + 50) / 100)
  44 #define PRF2PRI(PRF) ((1000000 + PRF / 2) / PRF)
  45 /* percentage of pulse width tolerance */
  46 #define WIDTH_TOLERANCE 5
  47 #define WIDTH_LOWER(X) ((X*(100-WIDTH_TOLERANCE)+50)/100)
  48 #define WIDTH_UPPER(X) ((X*(100+WIDTH_TOLERANCE)+50)/100)
  49
  50 #define ETSI_PATTERN(ID, WMIN, WMAX, PMIN, PMAX, PRF, PPB)      \
  51 {                                                               \
  52         ID, WIDTH_LOWER(WMIN), WIDTH_UPPER(WMAX),               \
  53         (PRF2PRI(PMAX) - PRI_TOLERANCE),                        \
  54         (PRF2PRI(PMIN) * PRF + PRI_TOLERANCE), PRF, PPB * PRF,  \
  55         PPB_THRESH(PPB), PRI_TOLERANCE,                         \
  56 }
  57
  58 /* radar types as defined by ETSI EN-301-893 v1.5.1 */
  59 static const struct radar_detector_specs etsi_radar_ref_types_v15[] = {
  60         ETSI_PATTERN(0,  0,  1,  700,  700, 1, 18),
  61         ETSI_PATTERN(1,  0,  5,  200, 1000, 1, 10),
  62         ETSI_PATTERN(2,  0, 15,  200, 1600, 1, 15),
  63         ETSI_PATTERN(3,  0, 15, 2300, 4000, 1, 25),
  64         ETSI_PATTERN(4, 20, 30, 2000, 4000, 1, 20),
  65         ETSI_PATTERN(5,  0,  2,  300,  400, 3, 10),
  66         ETSI_PATTERN(6,  0,  2,  400, 1200, 3, 15),
  67 };
  68
  69 static const struct radar_types etsi_radar_types_v15 = {
  70         .region                 = NL80211_DFS_ETSI,
  71         .num_radar_types        = ARRAY_SIZE(etsi_radar_ref_types_v15),
  72         .radar_types            = etsi_radar_ref_types_v15,
  73 };
  74
  75 /* for now, we support ETSI radar types, FCC and JP are TODO */
  76 static const struct radar_types *dfs_domains[] = {
  77         &etsi_radar_types_v15,
  78 };
  79
  80 /**
  81  * get_dfs_domain_radar_types() - get radar types for a given DFS domain
  82  * @param domain DFS domain
  83  * @return radar_types ptr on success, NULL if DFS domain is not supported
  84  */
  85 static const struct radar_types *
  86 get_dfs_domain_radar_types(enum nl80211_dfs_regions region)
  87 {
  88         u32 i;
  89         for (i = 0; i < ARRAY_SIZE(dfs_domains); i++) {
  90                 if (dfs_domains[i]->region == region)
  91                         return dfs_domains[i];
  92         }
  93         return NULL;
  94 }
  95
  96 /**
  97  * struct channel_detector - detector elements for a DFS channel
  98  * @head: list_head
  99  * @freq: frequency for this channel detector in MHz
 100  * @detectors: array of dynamically created detector elements for this freq
 101  *
 102  * Channel detectors are required to provide multi-channel DFS detection, e.g.
 103  * to support off-channel scanning. A pattern detector has a list of channels
 104  * radar pulses have been reported for in the past.
 105  */
 106 struct channel_detector {
 107         struct list_head head;
 108         u16 freq;
 109         struct pri_detector **detectors;
 110 };
 111
 112 /* channel_detector_reset() - reset detector lines for a given channel */
 113 static void channel_detector_reset(struct dfs_pattern_detector *dpd,
 114                                    struct channel_detector *cd)
 115 {
 116         u32 i;
 117         if (cd == NULL)
 118                 return;
 119         for (i = 0; i < dpd->num_radar_types; i++)
 120                 cd->detectors[i]->reset(cd->detectors[i], dpd->last_pulse_ts);
 121 }
 122
 123 /* channel_detector_exit() - destructor */
 124 static void channel_detector_exit(struct dfs_pattern_detector *dpd,
 125                                   struct channel_detector *cd)
 126 {
 127         u32 i;
 128         if (cd == NULL)
 129                 return;
 130         list_del(&cd->head);
 131         for (i = 0; i < dpd->num_radar_types; i++) {
 132                 struct pri_detector *de = cd->detectors[i];
 133                 if (de != NULL)
 134                         de->exit(de);
 135         }
 136         kfree(cd->detectors);
 137         kfree(cd);
 138 }
 139
 140 static struct channel_detector *
 141 channel_detector_create(struct dfs_pattern_detector *dpd, u16 freq)
 142 {
 143         u32 sz, i;
 144         struct channel_detector *cd;
 145
 146         cd = kmalloc(sizeof(*cd), GFP_ATOMIC);
 147         if (cd == NULL)
 148                 goto fail;
 149
 150         INIT_LIST_HEAD(&cd->head);
 151         cd->freq = freq;
 152         sz = sizeof(cd->detectors) * dpd->num_radar_types;
 153         cd->detectors = kzalloc(sz, GFP_ATOMIC);
 154         if (cd->detectors == NULL)
 155                 goto fail;
 156
 157         for (i = 0; i < dpd->num_radar_types; i++) {
 158                 const struct radar_detector_specs *rs = &dpd->radar_spec[i];
 159                 struct pri_detector *de = pri_detector_init(rs);
 160                 if (de == NULL)
 161                         goto fail;
 162                 cd->detectors[i] = de;
 163         }
 164         list_add(&cd->head, &dpd->channel_detectors);
 165         return cd;
 166
 167 fail:
 168         pr_err("failed to allocate channel_detector for freq=%d\n", freq);
 169         channel_detector_exit(dpd, cd);
 170         return NULL;
 171 }
 172
 173 /**
 174  * channel_detector_get() - get channel detector for given frequency
 175  * @param dpd instance pointer
 176  * @param freq frequency in MHz
 177  * @return pointer to channel detector on success, NULL otherwise
 178  *
 179  * Return existing channel detector for the given frequency or return a
 180  * newly create one.
 181  */
 182 static struct channel_detector *
 183 channel_detector_get(struct dfs_pattern_detector *dpd, u16 freq)
 184 {
 185         struct channel_detector *cd;
 186         list_for_each_entry(cd, &dpd->channel_detectors, head) {
 187                 if (cd->freq == freq)
 188                         return cd;
 189         }
 190         return channel_detector_create(dpd, freq);
 191 }
 192
 193 /*
 194  * DFS Pattern Detector
 195  */
 196
 197 /* dpd_reset(): reset all channel detectors */
 198 static void dpd_reset(struct dfs_pattern_detector *dpd)
 199 {
 200         struct channel_detector *cd;
 201         if (!list_empty(&dpd->channel_detectors))
 202                 list_for_each_entry(cd, &dpd->channel_detectors, head)
 203                         channel_detector_reset(dpd, cd);
 204
 205 }
 206 static void dpd_exit(struct dfs_pattern_detector *dpd)
 207 {
 208         struct channel_detector *cd, *cd0;
 209         if (!list_empty(&dpd->channel_detectors))
 210                 list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
 211                         channel_detector_exit(dpd, cd);
 212         kfree(dpd);
 213 }
 214
 215 static bool
 216 dpd_add_pulse(struct dfs_pattern_detector *dpd, struct pulse_event *event)
 217 {
 218         u32 i;
 219         bool ts_wraparound;
 220         struct channel_detector *cd;
 221
 222         if (dpd->region == NL80211_DFS_UNSET) {
 223                 /*
 224                  * pulses received for a non-supported or un-initialized
 225                  * domain are treated as detected radars
 226                  */
 227                 return true;
 228         }
 229
 230         cd = channel_detector_get(dpd, event->freq);
 231         if (cd == NULL)
 232                 return false;
 233
 234         ts_wraparound = (event->ts < dpd->last_pulse_ts);
 235         dpd->last_pulse_ts = event->ts;
 236         if (ts_wraparound) {
 237                 /*
 238                  * reset detector on time stamp wraparound
 239                  * with monotonic time stamps, this should never happen
 240                  */
 241                 pr_warn("DFS: time stamp wraparound detected, resetting\n");
 242                 dpd_reset(dpd);
 243         }
 244         /* do type individual pattern matching */
 245         for (i = 0; i < dpd->num_radar_types; i++) {
 246                 if (cd->detectors[i]->add_pulse(cd->detectors[i], event) != 0) {
 247                         channel_detector_reset(dpd, cd);
 248                         return true;
 249                 }
 250         }
 251         return false;
 252 }
 253
 254 static bool dpd_set_domain(struct dfs_pattern_detector *dpd,
 255                            enum nl80211_dfs_regions region)
 256 {
 257         const struct radar_types *rt;
 258         struct channel_detector *cd, *cd0;
 259
 260         if (dpd->region == region)
 261                 return true;
 262
 263         dpd->region = NL80211_DFS_UNSET;
 264
 265         rt = get_dfs_domain_radar_types(region);
 266         if (rt == NULL)
 267                 return false;
 268
 269         /* delete all channel detectors for previous DFS domain */
 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         dpd->radar_spec = rt->radar_types;
 274         dpd->num_radar_types = rt->num_radar_types;
 275
 276         dpd->region = region;
 277         return true;
 278 }
 279
 280 static struct dfs_pattern_detector default_dpd = {
 281         .exit           = dpd_exit,
 282         .set_dfs_domain = dpd_set_domain,
 283         .add_pulse      = dpd_add_pulse,
 284         .region         = NL80211_DFS_UNSET,
 285 };
 286
 287 struct dfs_pattern_detector *
 288 dfs_pattern_detector_init(enum nl80211_dfs_regions region)
 289 {
 290         struct dfs_pattern_detector *dpd;
 291
 292         dpd = kmalloc(sizeof(*dpd), GFP_KERNEL);
 293         if (dpd == NULL)
 294                 return NULL;
 295
 296         *dpd = default_dpd;
 297         INIT_LIST_HEAD(&dpd->channel_detectors);
 298
 299         if (dpd->set_dfs_domain(dpd, region))
 300                 return dpd;
 301
 302         pr_err("Could not set DFS domain to %d. ", region);
 303         kfree(dpd);
 304         return NULL;
 305 }
 306 EXPORT_SYMBOL(dfs_pattern_detector_init);