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 #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  */
  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 /* for now, we support ETSI radar types, FCC and JP are TODO */
  77 static 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  */
  86 static const struct radar_types *
  87 get_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  */
 107 struct 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 */
 114 static 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 */
 125 static 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
 141 static struct channel_detector *
 142 channel_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
 169 fail:
 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  */
 185 static struct channel_detector *
 186 channel_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 */
 201 static 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 }
 209 static 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
 218 static bool
 219 dpd_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
 257 static 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
 283 static 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
 290 struct dfs_pattern_detector *
 291 dfs_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 }
 311 EXPORT_SYMBOL(dfs_pattern_detector_init);