1 files changed, 429 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 000000000000..43b608178884
--- /dev/null
+++ b/drivers/net/wireless/ath/dfs_pri_detector.c
@@ -0,0 +1,429 @@
+/*
+ * 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--)
+
+/**
+ * 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 = 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;
+        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;
+}