1 files changed, 437 insertions, 0 deletions
diff --git a/drivers/net/wireless/ath/dfs_pri_detector.c b/drivers/net/wireless/ath/dfs_pri_detector.c
new file mode 100644
index 000000000..05b0464c6
--- /dev/null
+++ b/drivers/net/wireless/ath/dfs_pri_detector.c
@@ -0,0 +1,437 @@
+/*
+ * 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;
+}