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Diffstat (limited to 'drivers/net/wireless/ath/dfs_pri_detector.c')
-rw-r--r--drivers/net/wireless/ath/dfs_pri_detector.c437
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 0000000..05b0464
--- /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;
+}