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(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 */
  60 static 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
  70 static 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 #define FCC_PATTERN(ID, WMIN, WMAX, PMIN, PMAX, PRF, PPB)       \
  77 {                                                               \
  78         ID, WIDTH_LOWER(WMIN), WIDTH_UPPER(WMAX),               \
  79         PMIN - PRI_TOLERANCE,                                   \
  80         PMAX * PRF + PRI_TOLERANCE, PRF, PPB * PRF,             \
  81         PPB_THRESH(PPB), PRI_TOLERANCE,                         \
  82 }
  83
  84 static const struct radar_detector_specs fcc_radar_ref_types[] = {
  85         FCC_PATTERN(0, 0, 1, 1428, 1428, 1, 18),
  86         FCC_PATTERN(1, 0, 5, 150, 230, 1, 23),
  87         FCC_PATTERN(2, 6, 10, 200, 500, 1, 16),
  88         FCC_PATTERN(3, 11, 20, 200, 500, 1, 12),
  89         FCC_PATTERN(4, 50, 100, 1000, 2000, 20, 1),
  90         FCC_PATTERN(5, 0, 1, 333, 333, 1, 9),
  91 };
  92
  93 static const struct radar_types fcc_radar_types = {
  94         .region                 = NL80211_DFS_FCC,
  95         .num_radar_types        = ARRAY_SIZE(fcc_radar_ref_types),
  96         .radar_types            = fcc_radar_ref_types,
  97 };
  98
  99 #define JP_PATTERN FCC_PATTERN
 100 static const struct radar_detector_specs jp_radar_ref_types[] = {
 101         JP_PATTERN(0, 0, 1, 1428, 1428, 1, 18),
 102         JP_PATTERN(1, 2, 3, 3846, 3846, 1, 18),
 103         JP_PATTERN(2, 0, 1, 1388, 1388, 1, 18),
 104         JP_PATTERN(3, 1, 2, 4000, 4000, 1, 18),
 105         JP_PATTERN(4, 0, 5, 150, 230, 1, 23),
 106         JP_PATTERN(5, 6, 10, 200, 500, 1, 16),
 107         JP_PATTERN(6, 11, 20, 200, 500, 1, 12),
 108         JP_PATTERN(7, 50, 100, 1000, 2000, 20, 1),
 109         JP_PATTERN(5, 0, 1, 333, 333, 1, 9),
 110 };
 111
 112 static const struct radar_types jp_radar_types = {
 113         .region                 = NL80211_DFS_JP,
 114         .num_radar_types        = ARRAY_SIZE(jp_radar_ref_types),
 115         .radar_types            = jp_radar_ref_types,
 116 };
 117
 118 static const struct radar_types *dfs_domains[] = {
 119         &etsi_radar_types_v15,
 120         &fcc_radar_types,
 121         &jp_radar_types,
 122 };
 123
 124 /**
 125  * get_dfs_domain_radar_types() - get radar types for a given DFS domain
 126  * @param domain DFS domain
 127  * @return radar_types ptr on success, NULL if DFS domain is not supported
 128  */
 129 static const struct radar_types *
 130 get_dfs_domain_radar_types(enum nl80211_dfs_regions region)
 131 {
 132         u32 i;
 133         for (i = 0; i < ARRAY_SIZE(dfs_domains); i++) {
 134                 if (dfs_domains[i]->region == region)
 135                         return dfs_domains[i];
 136         }
 137         return NULL;
 138 }
 139
 140 /**
 141  * struct channel_detector - detector elements for a DFS channel
 142  * @head: list_head
 143  * @freq: frequency for this channel detector in MHz
 144  * @detectors: array of dynamically created detector elements for this freq
 145  *
 146  * Channel detectors are required to provide multi-channel DFS detection, e.g.
 147  * to support off-channel scanning. A pattern detector has a list of channels
 148  * radar pulses have been reported for in the past.
 149  */
 150 struct channel_detector {
 151         struct list_head head;
 152         u16 freq;
 153         struct pri_detector **detectors;
 154 };
 155
 156 /* channel_detector_reset() - reset detector lines for a given channel */
 157 static void channel_detector_reset(struct dfs_pattern_detector *dpd,
 158                                    struct channel_detector *cd)
 159 {
 160         u32 i;
 161         if (cd == NULL)
 162                 return;
 163         for (i = 0; i < dpd->num_radar_types; i++)
 164                 cd->detectors[i]->reset(cd->detectors[i], dpd->last_pulse_ts);
 165 }
 166
 167 /* channel_detector_exit() - destructor */
 168 static void channel_detector_exit(struct dfs_pattern_detector *dpd,
 169                                   struct channel_detector *cd)
 170 {
 171         u32 i;
 172         if (cd == NULL)
 173                 return;
 174         list_del(&cd->head);
 175         for (i = 0; i < dpd->num_radar_types; i++) {
 176                 struct pri_detector *de = cd->detectors[i];
 177                 if (de != NULL)
 178                         de->exit(de);
 179         }
 180         kfree(cd->detectors);
 181         kfree(cd);
 182 }
 183
 184 static struct channel_detector *
 185 channel_detector_create(struct dfs_pattern_detector *dpd, u16 freq)
 186 {
 187         u32 sz, i;
 188         struct channel_detector *cd;
 189
 190         cd = kmalloc(sizeof(*cd), GFP_ATOMIC);
 191         if (cd == NULL)
 192                 goto fail;
 193
 194         INIT_LIST_HEAD(&cd->head);
 195         cd->freq = freq;
 196         sz = sizeof(cd->detectors) * dpd->num_radar_types;
 197         cd->detectors = kzalloc(sz, GFP_ATOMIC);
 198         if (cd->detectors == NULL)
 199                 goto fail;
 200
 201         for (i = 0; i < dpd->num_radar_types; i++) {
 202                 const struct radar_detector_specs *rs = &dpd->radar_spec[i];
 203                 struct pri_detector *de = pri_detector_init(rs);
 204                 if (de == NULL)
 205                         goto fail;
 206                 cd->detectors[i] = de;
 207         }
 208         list_add(&cd->head, &dpd->channel_detectors);
 209         return cd;
 210
 211 fail:
 212         ath_dbg(dpd->common, DFS,
 213                 "failed to allocate channel_detector for freq=%d\n", freq);
 214         channel_detector_exit(dpd, cd);
 215         return NULL;
 216 }
 217
 218 /**
 219  * channel_detector_get() - get channel detector for given frequency
 220  * @param dpd instance pointer
 221  * @param freq frequency in MHz
 222  * @return pointer to channel detector on success, NULL otherwise
 223  *
 224  * Return existing channel detector for the given frequency or return a
 225  * newly create one.
 226  */
 227 static struct channel_detector *
 228 channel_detector_get(struct dfs_pattern_detector *dpd, u16 freq)
 229 {
 230         struct channel_detector *cd;
 231         list_for_each_entry(cd, &dpd->channel_detectors, head) {
 232                 if (cd->freq == freq)
 233                         return cd;
 234         }
 235         return channel_detector_create(dpd, freq);
 236 }
 237
 238 /*
 239  * DFS Pattern Detector
 240  */
 241
 242 /* dpd_reset(): reset all channel detectors */
 243 static void dpd_reset(struct dfs_pattern_detector *dpd)
 244 {
 245         struct channel_detector *cd;
 246         if (!list_empty(&dpd->channel_detectors))
 247                 list_for_each_entry(cd, &dpd->channel_detectors, head)
 248                         channel_detector_reset(dpd, cd);
 249
 250 }
 251 static void dpd_exit(struct dfs_pattern_detector *dpd)
 252 {
 253         struct channel_detector *cd, *cd0;
 254         if (!list_empty(&dpd->channel_detectors))
 255                 list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
 256                         channel_detector_exit(dpd, cd);
 257         kfree(dpd);
 258 }
 259
 260 static bool
 261 dpd_add_pulse(struct dfs_pattern_detector *dpd, struct pulse_event *event)
 262 {
 263         u32 i;
 264         struct channel_detector *cd;
 265
 266         /*
 267          * pulses received for a non-supported or un-initialized
 268          * domain are treated as detected radars for fail-safety
 269          */
 270         if (dpd->region == NL80211_DFS_UNSET)
 271                 return true;
 272
 273         cd = channel_detector_get(dpd, event->freq);
 274         if (cd == NULL)
 275                 return false;
 276
 277         dpd->last_pulse_ts = event->ts;
 278         /* reset detector on time stamp wraparound, caused by TSF reset */
 279         if (event->ts < dpd->last_pulse_ts)
 280                 dpd_reset(dpd);
 281
 282         /* do type individual pattern matching */
 283         for (i = 0; i < dpd->num_radar_types; i++) {
 284                 struct pri_detector *pd = cd->detectors[i];
 285                 struct pri_sequence *ps = pd->add_pulse(pd, event);
 286                 if (ps != NULL) {
 287                         ath_dbg(dpd->common, DFS,
 288                                 "DFS: radar found on freq=%d: id=%d, pri=%d, "
 289                                 "count=%d, count_false=%d\n",
 290                                 event->freq, pd->rs->type_id,
 291                                 ps->pri, ps->count, ps->count_falses);
 292                         channel_detector_reset(dpd, cd);
 293                         return true;
 294                 }
 295         }
 296         return false;
 297 }
 298
 299 static struct ath_dfs_pool_stats
 300 dpd_get_stats(struct dfs_pattern_detector *dpd)
 301 {
 302         return global_dfs_pool_stats;
 303 }
 304
 305 static bool dpd_set_domain(struct dfs_pattern_detector *dpd,
 306                            enum nl80211_dfs_regions region)
 307 {
 308         const struct radar_types *rt;
 309         struct channel_detector *cd, *cd0;
 310
 311         if (dpd->region == region)
 312                 return true;
 313
 314         dpd->region = NL80211_DFS_UNSET;
 315
 316         rt = get_dfs_domain_radar_types(region);
 317         if (rt == NULL)
 318                 return false;
 319
 320         /* delete all channel detectors for previous DFS domain */
 321         if (!list_empty(&dpd->channel_detectors))
 322                 list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
 323                         channel_detector_exit(dpd, cd);
 324         dpd->radar_spec = rt->radar_types;
 325         dpd->num_radar_types = rt->num_radar_types;
 326
 327         dpd->region = region;
 328         return true;
 329 }
 330
 331 static struct dfs_pattern_detector default_dpd = {
 332         .exit           = dpd_exit,
 333         .set_dfs_domain = dpd_set_domain,
 334         .add_pulse      = dpd_add_pulse,
 335         .get_stats      = dpd_get_stats,
 336         .region         = NL80211_DFS_UNSET,
 337 };
 338
 339 struct dfs_pattern_detector *
 340 dfs_pattern_detector_init(struct ath_common *common,
 341                           enum nl80211_dfs_regions region)
 342 {
 343         struct dfs_pattern_detector *dpd;
 344
 345         if (!config_enabled(CONFIG_CFG80211_CERTIFICATION_ONUS))
 346                 return NULL;
 347
 348         dpd = kmalloc(sizeof(*dpd), GFP_KERNEL);
 349         if (dpd == NULL)
 350                 return NULL;
 351
 352         *dpd = default_dpd;
 353         INIT_LIST_HEAD(&dpd->channel_detectors);
 354
 355         dpd->common = common;
 356         if (dpd->set_dfs_domain(dpd, region))
 357                 return dpd;
 358
 359         ath_dbg(common, DFS,"Could not set DFS domain to %d", region);
 360         kfree(dpd);
 361         return NULL;
 362 }
 363 EXPORT_SYMBOL(dfs_pattern_detector_init);