drivers/net/wireless/ath/dfs_pri_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/spinlock.h>
  19
  20 #include "ath.h"
  21 #include "dfs_pattern_detector.h"
  22 #include "dfs_pri_detector.h"
  23
  24 struct ath_dfs_pool_stats global_dfs_pool_stats = {};
  25
  26 #define DFS_POOL_STAT_INC(c) (global_dfs_pool_stats.c++)
  27 #define DFS_POOL_STAT_DEC(c) (global_dfs_pool_stats.c--)
  28 #define GET_PRI_TO_USE(MIN, MAX, RUNTIME) \
  29         (MIN + PRI_TOLERANCE == MAX - PRI_TOLERANCE ? \
  30         MIN + PRI_TOLERANCE : RUNTIME)
  31
  32 /*
  33  * struct pulse_elem - elements in pulse queue
  34  */
  35 struct pulse_elem {
  36         struct list_head head;
  37         u64 ts;
  38 };
  39
  40 /*
  41  * pde_get_multiple() - get number of multiples considering a given tolerance
  42  * Return value: factor if abs(val - factor*fraction) <= tolerance, 0 otherwise
  43  */
  44 static u32 pde_get_multiple(u32 val, u32 fraction, u32 tolerance)
  45 {
  46         u32 remainder;
  47         u32 factor;
  48         u32 delta;
  49
  50         if (fraction == 0)
  51                 return 0;
  52
  53         delta = (val < fraction) ? (fraction - val) : (val - fraction);
  54
  55         if (delta <= tolerance)
  56                 /* val and fraction are within tolerance */
  57                 return 1;
  58
  59         factor = val / fraction;
  60         remainder = val % fraction;
  61         if (remainder > tolerance) {
  62                 /* no exact match */
  63                 if ((fraction - remainder) <= tolerance)
  64                         /* remainder is within tolerance */
  65                         factor++;
  66                 else
  67                         factor = 0;
  68         }
  69         return factor;
  70 }
  71
  72 /*
  73  * DOC: Singleton Pulse and Sequence Pools
  74  *
  75  * Instances of pri_sequence and pulse_elem are kept in singleton pools to
  76  * reduce the number of dynamic allocations. They are shared between all
  77  * instances and grow up to the peak number of simultaneously used objects.
  78  *
  79  * Memory is freed after all references to the pools are released.
  80  */
  81 static u32 singleton_pool_references;
  82 static LIST_HEAD(pulse_pool);
  83 static LIST_HEAD(pseq_pool);
  84 static DEFINE_SPINLOCK(pool_lock);
  85
  86 static void pool_register_ref(void)
  87 {
  88         spin_lock_bh(&pool_lock);
  89         singleton_pool_references++;
  90         DFS_POOL_STAT_INC(pool_reference);
  91         spin_unlock_bh(&pool_lock);
  92 }
  93
  94 static void pool_deregister_ref(void)
  95 {
  96         spin_lock_bh(&pool_lock);
  97         singleton_pool_references--;
  98         DFS_POOL_STAT_DEC(pool_reference);
  99         if (singleton_pool_references == 0) {
 100                 /* free singleton pools with no references left */
 101                 struct pri_sequence *ps, *ps0;
 102                 struct pulse_elem *p, *p0;
 103
 104                 list_for_each_entry_safe(p, p0, &pulse_pool, head) {
 105                         list_del(&p->head);
 106                         DFS_POOL_STAT_DEC(pulse_allocated);
 107                         kfree(p);
 108                 }
 109                 list_for_each_entry_safe(ps, ps0, &pseq_pool, head) {
 110                         list_del(&ps->head);
 111                         DFS_POOL_STAT_DEC(pseq_allocated);
 112                         kfree(ps);
 113                 }
 114         }
 115         spin_unlock_bh(&pool_lock);
 116 }
 117
 118 static void pool_put_pulse_elem(struct pulse_elem *pe)
 119 {
 120         spin_lock_bh(&pool_lock);
 121         list_add(&pe->head, &pulse_pool);
 122         DFS_POOL_STAT_DEC(pulse_used);
 123         spin_unlock_bh(&pool_lock);
 124 }
 125
 126 static void pool_put_pseq_elem(struct pri_sequence *pse)
 127 {
 128         spin_lock_bh(&pool_lock);
 129         list_add(&pse->head, &pseq_pool);
 130         DFS_POOL_STAT_DEC(pseq_used);
 131         spin_unlock_bh(&pool_lock);
 132 }
 133
 134 static struct pri_sequence *pool_get_pseq_elem(void)
 135 {
 136         struct pri_sequence *pse = NULL;
 137         spin_lock_bh(&pool_lock);
 138         if (!list_empty(&pseq_pool)) {
 139                 pse = list_first_entry(&pseq_pool, struct pri_sequence, head);
 140                 list_del(&pse->head);
 141                 DFS_POOL_STAT_INC(pseq_used);
 142         }
 143         spin_unlock_bh(&pool_lock);
 144         return pse;
 145 }
 146
 147 static struct pulse_elem *pool_get_pulse_elem(void)
 148 {
 149         struct pulse_elem *pe = NULL;
 150         spin_lock_bh(&pool_lock);
 151         if (!list_empty(&pulse_pool)) {
 152                 pe = list_first_entry(&pulse_pool, struct pulse_elem, head);
 153                 list_del(&pe->head);
 154                 DFS_POOL_STAT_INC(pulse_used);
 155         }
 156         spin_unlock_bh(&pool_lock);
 157         return pe;
 158 }
 159
 160 static struct pulse_elem *pulse_queue_get_tail(struct pri_detector *pde)
 161 {
 162         struct list_head *l = &pde->pulses;
 163         if (list_empty(l))
 164                 return NULL;
 165         return list_entry(l->prev, struct pulse_elem, head);
 166 }
 167
 168 static bool pulse_queue_dequeue(struct pri_detector *pde)
 169 {
 170         struct pulse_elem *p = pulse_queue_get_tail(pde);
 171         if (p != NULL) {
 172                 list_del_init(&p->head);
 173                 pde->count--;
 174                 /* give it back to pool */
 175                 pool_put_pulse_elem(p);
 176         }
 177         return (pde->count > 0);
 178 }
 179
 180 /* remove pulses older than window */
 181 static void pulse_queue_check_window(struct pri_detector *pde)
 182 {
 183         u64 min_valid_ts;
 184         struct pulse_elem *p;
 185
 186         /* there is no delta time with less than 2 pulses */
 187         if (pde->count < 2)
 188                 return;
 189
 190         if (pde->last_ts <= pde->window_size)
 191                 return;
 192
 193         min_valid_ts = pde->last_ts - pde->window_size;
 194         while ((p = pulse_queue_get_tail(pde)) != NULL) {
 195                 if (p->ts >= min_valid_ts)
 196                         return;
 197                 pulse_queue_dequeue(pde);
 198         }
 199 }
 200
 201 static bool pulse_queue_enqueue(struct pri_detector *pde, u64 ts)
 202 {
 203         struct pulse_elem *p = pool_get_pulse_elem();
 204         if (p == NULL) {
 205                 p = kmalloc(sizeof(*p), GFP_ATOMIC);
 206                 if (p == NULL) {
 207                         DFS_POOL_STAT_INC(pulse_alloc_error);
 208                         return false;
 209                 }
 210                 DFS_POOL_STAT_INC(pulse_allocated);
 211                 DFS_POOL_STAT_INC(pulse_used);
 212         }
 213         INIT_LIST_HEAD(&p->head);
 214         p->ts = ts;
 215         list_add(&p->head, &pde->pulses);
 216         pde->count++;
 217         pde->last_ts = ts;
 218         pulse_queue_check_window(pde);
 219         if (pde->count >= pde->max_count)
 220                 pulse_queue_dequeue(pde);
 221         return true;
 222 }
 223
 224 static bool pseq_handler_create_sequences(struct pri_detector *pde,
 225                                           u64 ts, u32 min_count)
 226 {
 227         struct pulse_elem *p;
 228         list_for_each_entry(p, &pde->pulses, head) {
 229                 struct pri_sequence ps, *new_ps;
 230                 struct pulse_elem *p2;
 231                 u32 tmp_false_count;
 232                 u64 min_valid_ts;
 233                 u32 delta_ts = ts - p->ts;
 234
 235                 if (delta_ts < pde->rs->pri_min)
 236                         /* ignore too small pri */
 237                         continue;
 238
 239                 if (delta_ts > pde->rs->pri_max)
 240                         /* stop on too large pri (sorted list) */
 241                         break;
 242
 243                 /* build a new sequence with new potential pri */
 244                 ps.count = 2;
 245                 ps.count_falses = 0;
 246                 ps.first_ts = p->ts;
 247                 ps.last_ts = ts;
 248                 ps.pri = GET_PRI_TO_USE(pde->rs->pri_min,
 249                         pde->rs->pri_max, ts - p->ts);
 250                 ps.dur = ps.pri * (pde->rs->ppb - 1)
 251                                 + 2 * pde->rs->max_pri_tolerance;
 252
 253                 p2 = p;
 254                 tmp_false_count = 0;
 255                 min_valid_ts = ts - ps.dur;
 256                 /* check which past pulses are candidates for new sequence */
 257                 list_for_each_entry_continue(p2, &pde->pulses, head) {
 258                         u32 factor;
 259                         if (p2->ts < min_valid_ts)
 260                                 /* stop on crossing window border */
 261                                 break;
 262                         /* check if pulse match (multi)PRI */
 263                         factor = pde_get_multiple(ps.last_ts - p2->ts, ps.pri,
 264                                                   pde->rs->max_pri_tolerance);
 265                         if (factor > 0) {
 266                                 ps.count++;
 267                                 ps.first_ts = p2->ts;
 268                                 /*
 269                                  * on match, add the intermediate falses
 270                                  * and reset counter
 271                                  */
 272                                 ps.count_falses += tmp_false_count;
 273                                 tmp_false_count = 0;
 274                         } else {
 275                                 /* this is a potential false one */
 276                                 tmp_false_count++;
 277                         }
 278                 }
 279                 if (ps.count <= min_count)
 280                         /* did not reach minimum count, drop sequence */
 281                         continue;
 282
 283                 /* this is a valid one, add it */
 284                 ps.deadline_ts = ps.first_ts + ps.dur;
 285                 new_ps = pool_get_pseq_elem();
 286                 if (new_ps == NULL) {
 287                         new_ps = kmalloc(sizeof(*new_ps), GFP_ATOMIC);
 288                         if (new_ps == NULL) {
 289                                 DFS_POOL_STAT_INC(pseq_alloc_error);
 290                                 return false;
 291                         }
 292                         DFS_POOL_STAT_INC(pseq_allocated);
 293                         DFS_POOL_STAT_INC(pseq_used);
 294                 }
 295                 memcpy(new_ps, &ps, sizeof(ps));
 296                 INIT_LIST_HEAD(&new_ps->head);
 297                 list_add(&new_ps->head, &pde->sequences);
 298         }
 299         return true;
 300 }
 301
 302 /* check new ts and add to all matching existing sequences */
 303 static u32
 304 pseq_handler_add_to_existing_seqs(struct pri_detector *pde, u64 ts)
 305 {
 306         u32 max_count = 0;
 307         struct pri_sequence *ps, *ps2;
 308         list_for_each_entry_safe(ps, ps2, &pde->sequences, head) {
 309                 u32 delta_ts;
 310                 u32 factor;
 311
 312                 /* first ensure that sequence is within window */
 313                 if (ts > ps->deadline_ts) {
 314                         list_del_init(&ps->head);
 315                         pool_put_pseq_elem(ps);
 316                         continue;
 317                 }
 318
 319                 delta_ts = ts - ps->last_ts;
 320                 factor = pde_get_multiple(delta_ts, ps->pri,
 321                                           pde->rs->max_pri_tolerance);
 322                 if (factor > 0) {
 323                         ps->last_ts = ts;
 324                         ps->count++;
 325
 326                         if (max_count < ps->count)
 327                                 max_count = ps->count;
 328                 } else {
 329                         ps->count_falses++;
 330                 }
 331         }
 332         return max_count;
 333 }
 334
 335 static struct pri_sequence *
 336 pseq_handler_check_detection(struct pri_detector *pde)
 337 {
 338         struct pri_sequence *ps;
 339
 340         if (list_empty(&pde->sequences))
 341                 return NULL;
 342
 343         list_for_each_entry(ps, &pde->sequences, head) {
 344                 /*
 345                  * we assume to have enough matching confidence if we
 346                  * 1) have enough pulses
 347                  * 2) have more matching than false pulses
 348                  */
 349                 if ((ps->count >= pde->rs->ppb_thresh) &&
 350                     (ps->count * pde->rs->num_pri >= ps->count_falses))
 351                         return ps;
 352         }
 353         return NULL;
 354 }
 355
 356
 357 /* free pulse queue and sequences list and give objects back to pools */
 358 static void pri_detector_reset(struct pri_detector *pde, u64 ts)
 359 {
 360         struct pri_sequence *ps, *ps0;
 361         struct pulse_elem *p, *p0;
 362         list_for_each_entry_safe(ps, ps0, &pde->sequences, head) {
 363                 list_del_init(&ps->head);
 364                 pool_put_pseq_elem(ps);
 365         }
 366         list_for_each_entry_safe(p, p0, &pde->pulses, head) {
 367                 list_del_init(&p->head);
 368                 pool_put_pulse_elem(p);
 369         }
 370         pde->count = 0;
 371         pde->last_ts = ts;
 372 }
 373
 374 static void pri_detector_exit(struct pri_detector *de)
 375 {
 376         pri_detector_reset(de, 0);
 377         pool_deregister_ref();
 378         kfree(de);
 379 }
 380
 381 static struct pri_sequence *pri_detector_add_pulse(struct pri_detector *de,
 382                                                    struct pulse_event *event)
 383 {
 384         u32 max_updated_seq;
 385         struct pri_sequence *ps;
 386         u64 ts = event->ts;
 387         const struct radar_detector_specs *rs = de->rs;
 388
 389         /* ignore pulses not within width range */
 390         if ((rs->width_min > event->width) || (rs->width_max < event->width))
 391                 return NULL;
 392
 393         if ((ts - de->last_ts) < rs->max_pri_tolerance)
 394                 /* if delta to last pulse is too short, don't use this pulse */
 395                 return NULL;
 396         /* radar detector spec needs chirp, but not detected */
 397         if (rs->chirp && rs->chirp != event->chirp)
 398                 return NULL;
 399
 400         de->last_ts = ts;
 401
 402         max_updated_seq = pseq_handler_add_to_existing_seqs(de, ts);
 403
 404         if (!pseq_handler_create_sequences(de, ts, max_updated_seq)) {
 405                 pri_detector_reset(de, ts);
 406                 return NULL;
 407         }
 408
 409         ps = pseq_handler_check_detection(de);
 410
 411         if (ps == NULL)
 412                 pulse_queue_enqueue(de, ts);
 413
 414         return ps;
 415 }
 416
 417 struct pri_detector *pri_detector_init(const struct radar_detector_specs *rs)
 418 {
 419         struct pri_detector *de;
 420
 421         de = kzalloc(sizeof(*de), GFP_ATOMIC);
 422         if (de == NULL)
 423                 return NULL;
 424         de->exit = pri_detector_exit;
 425         de->add_pulse = pri_detector_add_pulse;
 426         de->reset = pri_detector_reset;
 427
 428         INIT_LIST_HEAD(&de->sequences);
 429         INIT_LIST_HEAD(&de->pulses);
 430         de->window_size = rs->pri_max * rs->ppb * rs->num_pri;
 431         de->max_count = rs->ppb * 2;
 432         de->rs = rs;
 433
 434         pool_register_ref();
 435         return de;
 436 }