summaryrefslogtreecommitdiff
path: root/drivers/net/wireless/ath/dfs_pri_detector.c
blob: 05b0464c6b92c35fb7ccf30c66578450e15d4e68 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
/*
 * Copyright (c) 2012 Neratec Solutions AG
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <linux/slab.h>
#include <linux/spinlock.h>

#include "ath.h"
#include "dfs_pattern_detector.h"
#include "dfs_pri_detector.h"

struct ath_dfs_pool_stats global_dfs_pool_stats = {};

#define DFS_POOL_STAT_INC(c) (global_dfs_pool_stats.c++)
#define DFS_POOL_STAT_DEC(c) (global_dfs_pool_stats.c--)
#define GET_PRI_TO_USE(MIN, MAX, RUNTIME) \
	(MIN + PRI_TOLERANCE == MAX - PRI_TOLERANCE ? \
	MIN + PRI_TOLERANCE : RUNTIME)

/**
 * struct pulse_elem - elements in pulse queue
 * @ts: time stamp in usecs
 */
struct pulse_elem {
	struct list_head head;
	u64 ts;
};

/**
 * pde_get_multiple() - get number of multiples considering a given tolerance
 * @return factor if abs(val - factor*fraction) <= tolerance, 0 otherwise
 */
static u32 pde_get_multiple(u32 val, u32 fraction, u32 tolerance)
{
	u32 remainder;
	u32 factor;
	u32 delta;

	if (fraction == 0)
		return 0;

	delta = (val < fraction) ? (fraction - val) : (val - fraction);

	if (delta <= tolerance)
		/* val and fraction are within tolerance */
		return 1;

	factor = val / fraction;
	remainder = val % fraction;
	if (remainder > tolerance) {
		/* no exact match */
		if ((fraction - remainder) <= tolerance)
			/* remainder is within tolerance */
			factor++;
		else
			factor = 0;
	}
	return factor;
}

/**
 * DOC: Singleton Pulse and Sequence Pools
 *
 * Instances of pri_sequence and pulse_elem are kept in singleton pools to
 * reduce the number of dynamic allocations. They are shared between all
 * instances and grow up to the peak number of simultaneously used objects.
 *
 * Memory is freed after all references to the pools are released.
 */
static u32 singleton_pool_references;
static LIST_HEAD(pulse_pool);
static LIST_HEAD(pseq_pool);
static DEFINE_SPINLOCK(pool_lock);

static void pool_register_ref(void)
{
	spin_lock_bh(&pool_lock);
	singleton_pool_references++;
	DFS_POOL_STAT_INC(pool_reference);
	spin_unlock_bh(&pool_lock);
}

static void pool_deregister_ref(void)
{
	spin_lock_bh(&pool_lock);
	singleton_pool_references--;
	DFS_POOL_STAT_DEC(pool_reference);
	if (singleton_pool_references == 0) {
		/* free singleton pools with no references left */
		struct pri_sequence *ps, *ps0;
		struct pulse_elem *p, *p0;

		list_for_each_entry_safe(p, p0, &pulse_pool, head) {
			list_del(&p->head);
			DFS_POOL_STAT_DEC(pulse_allocated);
			kfree(p);
		}
		list_for_each_entry_safe(ps, ps0, &pseq_pool, head) {
			list_del(&ps->head);
			DFS_POOL_STAT_DEC(pseq_allocated);
			kfree(ps);
		}
	}
	spin_unlock_bh(&pool_lock);
}

static void pool_put_pulse_elem(struct pulse_elem *pe)
{
	spin_lock_bh(&pool_lock);
	list_add(&pe->head, &pulse_pool);
	DFS_POOL_STAT_DEC(pulse_used);
	spin_unlock_bh(&pool_lock);
}

static void pool_put_pseq_elem(struct pri_sequence *pse)
{
	spin_lock_bh(&pool_lock);
	list_add(&pse->head, &pseq_pool);
	DFS_POOL_STAT_DEC(pseq_used);
	spin_unlock_bh(&pool_lock);
}

static struct pri_sequence *pool_get_pseq_elem(void)
{
	struct pri_sequence *pse = NULL;
	spin_lock_bh(&pool_lock);
	if (!list_empty(&pseq_pool)) {
		pse = list_first_entry(&pseq_pool, struct pri_sequence, head);
		list_del(&pse->head);
		DFS_POOL_STAT_INC(pseq_used);
	}
	spin_unlock_bh(&pool_lock);
	return pse;
}

static struct pulse_elem *pool_get_pulse_elem(void)
{
	struct pulse_elem *pe = NULL;
	spin_lock_bh(&pool_lock);
	if (!list_empty(&pulse_pool)) {
		pe = list_first_entry(&pulse_pool, struct pulse_elem, head);
		list_del(&pe->head);
		DFS_POOL_STAT_INC(pulse_used);
	}
	spin_unlock_bh(&pool_lock);
	return pe;
}

static struct pulse_elem *pulse_queue_get_tail(struct pri_detector *pde)
{
	struct list_head *l = &pde->pulses;
	if (list_empty(l))
		return NULL;
	return list_entry(l->prev, struct pulse_elem, head);
}

static bool pulse_queue_dequeue(struct pri_detector *pde)
{
	struct pulse_elem *p = pulse_queue_get_tail(pde);
	if (p != NULL) {
		list_del_init(&p->head);
		pde->count--;
		/* give it back to pool */
		pool_put_pulse_elem(p);
	}
	return (pde->count > 0);
}

/* remove pulses older than window */
static void pulse_queue_check_window(struct pri_detector *pde)
{
	u64 min_valid_ts;
	struct pulse_elem *p;

	/* there is no delta time with less than 2 pulses */
	if (pde->count < 2)
		return;

	if (pde->last_ts <= pde->window_size)
		return;

	min_valid_ts = pde->last_ts - pde->window_size;
	while ((p = pulse_queue_get_tail(pde)) != NULL) {
		if (p->ts >= min_valid_ts)
			return;
		pulse_queue_dequeue(pde);
	}
}

static bool pulse_queue_enqueue(struct pri_detector *pde, u64 ts)
{
	struct pulse_elem *p = pool_get_pulse_elem();
	if (p == NULL) {
		p = kmalloc(sizeof(*p), GFP_ATOMIC);
		if (p == NULL) {
			DFS_POOL_STAT_INC(pulse_alloc_error);
			return false;
		}
		DFS_POOL_STAT_INC(pulse_allocated);
		DFS_POOL_STAT_INC(pulse_used);
	}
	INIT_LIST_HEAD(&p->head);
	p->ts = ts;
	list_add(&p->head, &pde->pulses);
	pde->count++;
	pde->last_ts = ts;
	pulse_queue_check_window(pde);
	if (pde->count >= pde->max_count)
		pulse_queue_dequeue(pde);
	return true;
}

static bool pseq_handler_create_sequences(struct pri_detector *pde,
					  u64 ts, u32 min_count)
{
	struct pulse_elem *p;
	list_for_each_entry(p, &pde->pulses, head) {
		struct pri_sequence ps, *new_ps;
		struct pulse_elem *p2;
		u32 tmp_false_count;
		u64 min_valid_ts;
		u32 delta_ts = ts - p->ts;

		if (delta_ts < pde->rs->pri_min)
			/* ignore too small pri */
			continue;

		if (delta_ts > pde->rs->pri_max)
			/* stop on too large pri (sorted list) */
			break;

		/* build a new sequence with new potential pri */
		ps.count = 2;
		ps.count_falses = 0;
		ps.first_ts = p->ts;
		ps.last_ts = ts;
		ps.pri = GET_PRI_TO_USE(pde->rs->pri_min,
			pde->rs->pri_max, ts - p->ts);
		ps.dur = ps.pri * (pde->rs->ppb - 1)
				+ 2 * pde->rs->max_pri_tolerance;

		p2 = p;
		tmp_false_count = 0;
		min_valid_ts = ts - ps.dur;
		/* check which past pulses are candidates for new sequence */
		list_for_each_entry_continue(p2, &pde->pulses, head) {
			u32 factor;
			if (p2->ts < min_valid_ts)
				/* stop on crossing window border */
				break;
			/* check if pulse match (multi)PRI */
			factor = pde_get_multiple(ps.last_ts - p2->ts, ps.pri,
						  pde->rs->max_pri_tolerance);
			if (factor > 0) {
				ps.count++;
				ps.first_ts = p2->ts;
				/*
				 * on match, add the intermediate falses
				 * and reset counter
				 */
				ps.count_falses += tmp_false_count;
				tmp_false_count = 0;
			} else {
				/* this is a potential false one */
				tmp_false_count++;
			}
		}
		if (ps.count <= min_count)
			/* did not reach minimum count, drop sequence */
			continue;

		/* this is a valid one, add it */
		ps.deadline_ts = ps.first_ts + ps.dur;
		new_ps = pool_get_pseq_elem();
		if (new_ps == NULL) {
			new_ps = kmalloc(sizeof(*new_ps), GFP_ATOMIC);
			if (new_ps == NULL) {
				DFS_POOL_STAT_INC(pseq_alloc_error);
				return false;
			}
			DFS_POOL_STAT_INC(pseq_allocated);
			DFS_POOL_STAT_INC(pseq_used);
		}
		memcpy(new_ps, &ps, sizeof(ps));
		INIT_LIST_HEAD(&new_ps->head);
		list_add(&new_ps->head, &pde->sequences);
	}
	return true;
}

/* check new ts and add to all matching existing sequences */
static u32
pseq_handler_add_to_existing_seqs(struct pri_detector *pde, u64 ts)
{
	u32 max_count = 0;
	struct pri_sequence *ps, *ps2;
	list_for_each_entry_safe(ps, ps2, &pde->sequences, head) {
		u32 delta_ts;
		u32 factor;

		/* first ensure that sequence is within window */
		if (ts > ps->deadline_ts) {
			list_del_init(&ps->head);
			pool_put_pseq_elem(ps);
			continue;
		}

		delta_ts = ts - ps->last_ts;
		factor = pde_get_multiple(delta_ts, ps->pri,
					  pde->rs->max_pri_tolerance);
		if (factor > 0) {
			ps->last_ts = ts;
			ps->count++;

			if (max_count < ps->count)
				max_count = ps->count;
		} else {
			ps->count_falses++;
		}
	}
	return max_count;
}

static struct pri_sequence *
pseq_handler_check_detection(struct pri_detector *pde)
{
	struct pri_sequence *ps;

	if (list_empty(&pde->sequences))
		return NULL;

	list_for_each_entry(ps, &pde->sequences, head) {
		/*
		 * we assume to have enough matching confidence if we
		 * 1) have enough pulses
		 * 2) have more matching than false pulses
		 */
		if ((ps->count >= pde->rs->ppb_thresh) &&
		    (ps->count * pde->rs->num_pri >= ps->count_falses))
			return ps;
	}
	return NULL;
}


/* free pulse queue and sequences list and give objects back to pools */
static void pri_detector_reset(struct pri_detector *pde, u64 ts)
{
	struct pri_sequence *ps, *ps0;
	struct pulse_elem *p, *p0;
	list_for_each_entry_safe(ps, ps0, &pde->sequences, head) {
		list_del_init(&ps->head);
		pool_put_pseq_elem(ps);
	}
	list_for_each_entry_safe(p, p0, &pde->pulses, head) {
		list_del_init(&p->head);
		pool_put_pulse_elem(p);
	}
	pde->count = 0;
	pde->last_ts = ts;
}

static void pri_detector_exit(struct pri_detector *de)
{
	pri_detector_reset(de, 0);
	pool_deregister_ref();
	kfree(de);
}

static struct pri_sequence *pri_detector_add_pulse(struct pri_detector *de,
						   struct pulse_event *event)
{
	u32 max_updated_seq;
	struct pri_sequence *ps;
	u64 ts = event->ts;
	const struct radar_detector_specs *rs = de->rs;

	/* ignore pulses not within width range */
	if ((rs->width_min > event->width) || (rs->width_max < event->width))
		return NULL;

	if ((ts - de->last_ts) < rs->max_pri_tolerance)
		/* if delta to last pulse is too short, don't use this pulse */
		return NULL;
	/* radar detector spec needs chirp, but not detected */
	if (rs->chirp && rs->chirp != event->chirp)
		return NULL;

	de->last_ts = ts;

	max_updated_seq = pseq_handler_add_to_existing_seqs(de, ts);

	if (!pseq_handler_create_sequences(de, ts, max_updated_seq)) {
		pri_detector_reset(de, ts);
		return NULL;
	}

	ps = pseq_handler_check_detection(de);

	if (ps == NULL)
		pulse_queue_enqueue(de, ts);

	return ps;
}

struct pri_detector *pri_detector_init(const struct radar_detector_specs *rs)
{
	struct pri_detector *de;

	de = kzalloc(sizeof(*de), GFP_ATOMIC);
	if (de == NULL)
		return NULL;
	de->exit = pri_detector_exit;
	de->add_pulse = pri_detector_add_pulse;
	de->reset = pri_detector_reset;

	INIT_LIST_HEAD(&de->sequences);
	INIT_LIST_HEAD(&de->pulses);
	de->window_size = rs->pri_max * rs->ppb * rs->num_pri;
	de->max_count = rs->ppb * 2;
	de->rs = rs;

	pool_register_ref();
	return de;
}