![Janusz Dziedzic](/assets/img/avatar_default.png)
Move the DFS pattern detector code to the ath module so the other Atheros drivers can make us of it. This makes no functional changes. Signed-off-by: Janusz Dziedzic <janusz.dziedzic@tieto.com> Reviewed-by: Luis R. Rodriguez <mcgrof@do-not-panic.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
430 lines
10 KiB
C
430 lines
10 KiB
C
/*
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* Copyright (c) 2012 Neratec Solutions AG
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include "ath.h"
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#include "dfs_pattern_detector.h"
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#include "dfs_pri_detector.h"
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struct ath_dfs_pool_stats global_dfs_pool_stats = {};
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#define DFS_POOL_STAT_INC(c) (global_dfs_pool_stats.c++)
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#define DFS_POOL_STAT_DEC(c) (global_dfs_pool_stats.c--)
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/**
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* struct pulse_elem - elements in pulse queue
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* @ts: time stamp in usecs
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*/
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struct pulse_elem {
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struct list_head head;
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u64 ts;
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};
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/**
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* pde_get_multiple() - get number of multiples considering a given tolerance
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* @return factor if abs(val - factor*fraction) <= tolerance, 0 otherwise
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*/
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static u32 pde_get_multiple(u32 val, u32 fraction, u32 tolerance)
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{
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u32 remainder;
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u32 factor;
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u32 delta;
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if (fraction == 0)
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return 0;
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delta = (val < fraction) ? (fraction - val) : (val - fraction);
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if (delta <= tolerance)
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/* val and fraction are within tolerance */
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return 1;
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factor = val / fraction;
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remainder = val % fraction;
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if (remainder > tolerance) {
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/* no exact match */
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if ((fraction - remainder) <= tolerance)
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/* remainder is within tolerance */
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factor++;
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else
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factor = 0;
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}
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return factor;
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}
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/**
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* DOC: Singleton Pulse and Sequence Pools
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*
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* Instances of pri_sequence and pulse_elem are kept in singleton pools to
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* reduce the number of dynamic allocations. They are shared between all
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* instances and grow up to the peak number of simultaneously used objects.
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*
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* Memory is freed after all references to the pools are released.
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*/
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static u32 singleton_pool_references;
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static LIST_HEAD(pulse_pool);
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static LIST_HEAD(pseq_pool);
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static DEFINE_SPINLOCK(pool_lock);
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static void pool_register_ref(void)
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{
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spin_lock_bh(&pool_lock);
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singleton_pool_references++;
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DFS_POOL_STAT_INC(pool_reference);
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spin_unlock_bh(&pool_lock);
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}
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static void pool_deregister_ref(void)
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{
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spin_lock_bh(&pool_lock);
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singleton_pool_references--;
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DFS_POOL_STAT_DEC(pool_reference);
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if (singleton_pool_references == 0) {
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/* free singleton pools with no references left */
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struct pri_sequence *ps, *ps0;
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struct pulse_elem *p, *p0;
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list_for_each_entry_safe(p, p0, &pulse_pool, head) {
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list_del(&p->head);
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DFS_POOL_STAT_DEC(pulse_allocated);
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kfree(p);
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}
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list_for_each_entry_safe(ps, ps0, &pseq_pool, head) {
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list_del(&ps->head);
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DFS_POOL_STAT_DEC(pseq_allocated);
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kfree(ps);
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}
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}
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spin_unlock_bh(&pool_lock);
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}
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static void pool_put_pulse_elem(struct pulse_elem *pe)
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{
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spin_lock_bh(&pool_lock);
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list_add(&pe->head, &pulse_pool);
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DFS_POOL_STAT_DEC(pulse_used);
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spin_unlock_bh(&pool_lock);
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}
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static void pool_put_pseq_elem(struct pri_sequence *pse)
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{
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spin_lock_bh(&pool_lock);
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list_add(&pse->head, &pseq_pool);
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DFS_POOL_STAT_DEC(pseq_used);
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spin_unlock_bh(&pool_lock);
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}
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static struct pri_sequence *pool_get_pseq_elem(void)
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{
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struct pri_sequence *pse = NULL;
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spin_lock_bh(&pool_lock);
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if (!list_empty(&pseq_pool)) {
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pse = list_first_entry(&pseq_pool, struct pri_sequence, head);
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list_del(&pse->head);
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DFS_POOL_STAT_INC(pseq_used);
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}
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spin_unlock_bh(&pool_lock);
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return pse;
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}
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static struct pulse_elem *pool_get_pulse_elem(void)
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{
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struct pulse_elem *pe = NULL;
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spin_lock_bh(&pool_lock);
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if (!list_empty(&pulse_pool)) {
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pe = list_first_entry(&pulse_pool, struct pulse_elem, head);
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list_del(&pe->head);
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DFS_POOL_STAT_INC(pulse_used);
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}
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spin_unlock_bh(&pool_lock);
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return pe;
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}
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static struct pulse_elem *pulse_queue_get_tail(struct pri_detector *pde)
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{
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struct list_head *l = &pde->pulses;
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if (list_empty(l))
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return NULL;
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return list_entry(l->prev, struct pulse_elem, head);
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}
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static bool pulse_queue_dequeue(struct pri_detector *pde)
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{
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struct pulse_elem *p = pulse_queue_get_tail(pde);
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if (p != NULL) {
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list_del_init(&p->head);
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pde->count--;
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/* give it back to pool */
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pool_put_pulse_elem(p);
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}
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return (pde->count > 0);
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}
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/* remove pulses older than window */
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static void pulse_queue_check_window(struct pri_detector *pde)
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{
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u64 min_valid_ts;
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struct pulse_elem *p;
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/* there is no delta time with less than 2 pulses */
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if (pde->count < 2)
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return;
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if (pde->last_ts <= pde->window_size)
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return;
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min_valid_ts = pde->last_ts - pde->window_size;
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while ((p = pulse_queue_get_tail(pde)) != NULL) {
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if (p->ts >= min_valid_ts)
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return;
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pulse_queue_dequeue(pde);
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}
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}
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static bool pulse_queue_enqueue(struct pri_detector *pde, u64 ts)
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{
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struct pulse_elem *p = pool_get_pulse_elem();
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if (p == NULL) {
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p = kmalloc(sizeof(*p), GFP_ATOMIC);
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if (p == NULL) {
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DFS_POOL_STAT_INC(pulse_alloc_error);
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return false;
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}
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DFS_POOL_STAT_INC(pulse_allocated);
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DFS_POOL_STAT_INC(pulse_used);
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}
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INIT_LIST_HEAD(&p->head);
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p->ts = ts;
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list_add(&p->head, &pde->pulses);
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pde->count++;
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pde->last_ts = ts;
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pulse_queue_check_window(pde);
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if (pde->count >= pde->max_count)
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pulse_queue_dequeue(pde);
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return true;
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}
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static bool pseq_handler_create_sequences(struct pri_detector *pde,
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u64 ts, u32 min_count)
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{
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struct pulse_elem *p;
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list_for_each_entry(p, &pde->pulses, head) {
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struct pri_sequence ps, *new_ps;
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struct pulse_elem *p2;
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u32 tmp_false_count;
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u64 min_valid_ts;
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u32 delta_ts = ts - p->ts;
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if (delta_ts < pde->rs->pri_min)
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/* ignore too small pri */
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continue;
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if (delta_ts > pde->rs->pri_max)
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/* stop on too large pri (sorted list) */
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break;
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/* build a new sequence with new potential pri */
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ps.count = 2;
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ps.count_falses = 0;
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ps.first_ts = p->ts;
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ps.last_ts = ts;
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ps.pri = ts - p->ts;
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ps.dur = ps.pri * (pde->rs->ppb - 1)
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+ 2 * pde->rs->max_pri_tolerance;
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p2 = p;
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tmp_false_count = 0;
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min_valid_ts = ts - ps.dur;
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/* check which past pulses are candidates for new sequence */
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list_for_each_entry_continue(p2, &pde->pulses, head) {
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u32 factor;
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if (p2->ts < min_valid_ts)
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/* stop on crossing window border */
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break;
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/* check if pulse match (multi)PRI */
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factor = pde_get_multiple(ps.last_ts - p2->ts, ps.pri,
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pde->rs->max_pri_tolerance);
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if (factor > 0) {
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ps.count++;
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ps.first_ts = p2->ts;
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/*
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* on match, add the intermediate falses
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* and reset counter
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*/
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ps.count_falses += tmp_false_count;
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tmp_false_count = 0;
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} else {
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/* this is a potential false one */
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tmp_false_count++;
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}
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}
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if (ps.count < min_count)
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/* did not reach minimum count, drop sequence */
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continue;
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/* this is a valid one, add it */
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ps.deadline_ts = ps.first_ts + ps.dur;
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new_ps = pool_get_pseq_elem();
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if (new_ps == NULL) {
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new_ps = kmalloc(sizeof(*new_ps), GFP_ATOMIC);
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if (new_ps == NULL) {
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DFS_POOL_STAT_INC(pseq_alloc_error);
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return false;
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}
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DFS_POOL_STAT_INC(pseq_allocated);
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DFS_POOL_STAT_INC(pseq_used);
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}
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memcpy(new_ps, &ps, sizeof(ps));
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INIT_LIST_HEAD(&new_ps->head);
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list_add(&new_ps->head, &pde->sequences);
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}
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return true;
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}
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/* check new ts and add to all matching existing sequences */
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static u32
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pseq_handler_add_to_existing_seqs(struct pri_detector *pde, u64 ts)
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{
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u32 max_count = 0;
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struct pri_sequence *ps, *ps2;
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list_for_each_entry_safe(ps, ps2, &pde->sequences, head) {
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u32 delta_ts;
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u32 factor;
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/* first ensure that sequence is within window */
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if (ts > ps->deadline_ts) {
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list_del_init(&ps->head);
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pool_put_pseq_elem(ps);
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continue;
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}
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delta_ts = ts - ps->last_ts;
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factor = pde_get_multiple(delta_ts, ps->pri,
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pde->rs->max_pri_tolerance);
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if (factor > 0) {
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ps->last_ts = ts;
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ps->count++;
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if (max_count < ps->count)
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max_count = ps->count;
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} else {
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ps->count_falses++;
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}
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}
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return max_count;
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}
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static struct pri_sequence *
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pseq_handler_check_detection(struct pri_detector *pde)
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{
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struct pri_sequence *ps;
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if (list_empty(&pde->sequences))
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return NULL;
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list_for_each_entry(ps, &pde->sequences, head) {
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/*
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* we assume to have enough matching confidence if we
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* 1) have enough pulses
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* 2) have more matching than false pulses
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*/
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if ((ps->count >= pde->rs->ppb_thresh) &&
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(ps->count * pde->rs->num_pri >= ps->count_falses))
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return ps;
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}
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return NULL;
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}
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/* free pulse queue and sequences list and give objects back to pools */
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static void pri_detector_reset(struct pri_detector *pde, u64 ts)
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{
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struct pri_sequence *ps, *ps0;
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struct pulse_elem *p, *p0;
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list_for_each_entry_safe(ps, ps0, &pde->sequences, head) {
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list_del_init(&ps->head);
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pool_put_pseq_elem(ps);
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}
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list_for_each_entry_safe(p, p0, &pde->pulses, head) {
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list_del_init(&p->head);
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pool_put_pulse_elem(p);
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}
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pde->count = 0;
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pde->last_ts = ts;
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}
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static void pri_detector_exit(struct pri_detector *de)
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{
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pri_detector_reset(de, 0);
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pool_deregister_ref();
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kfree(de);
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}
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static struct pri_sequence *pri_detector_add_pulse(struct pri_detector *de,
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struct pulse_event *event)
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{
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u32 max_updated_seq;
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struct pri_sequence *ps;
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u64 ts = event->ts;
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const struct radar_detector_specs *rs = de->rs;
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/* ignore pulses not within width range */
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if ((rs->width_min > event->width) || (rs->width_max < event->width))
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return NULL;
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if ((ts - de->last_ts) < rs->max_pri_tolerance)
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/* if delta to last pulse is too short, don't use this pulse */
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return NULL;
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de->last_ts = ts;
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max_updated_seq = pseq_handler_add_to_existing_seqs(de, ts);
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if (!pseq_handler_create_sequences(de, ts, max_updated_seq)) {
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pri_detector_reset(de, ts);
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return NULL;
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}
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ps = pseq_handler_check_detection(de);
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if (ps == NULL)
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pulse_queue_enqueue(de, ts);
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return ps;
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}
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struct pri_detector *pri_detector_init(const struct radar_detector_specs *rs)
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{
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struct pri_detector *de;
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de = kzalloc(sizeof(*de), GFP_ATOMIC);
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if (de == NULL)
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return NULL;
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de->exit = pri_detector_exit;
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de->add_pulse = pri_detector_add_pulse;
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de->reset = pri_detector_reset;
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INIT_LIST_HEAD(&de->sequences);
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INIT_LIST_HEAD(&de->pulses);
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de->window_size = rs->pri_max * rs->ppb * rs->num_pri;
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de->max_count = rs->ppb * 2;
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de->rs = rs;
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pool_register_ref();
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return de;
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}
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