301 lines
8.2 KiB
C
301 lines
8.2 KiB
C
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/*
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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/export.h>
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#include "dfs_pattern_detector.h"
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#include "dfs_pri_detector.h"
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/*
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* tolerated deviation of radar time stamp in usecs on both sides
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* TODO: this might need to be HW-dependent
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*/
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#define PRI_TOLERANCE 16
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/**
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* struct radar_types - contains array of patterns defined for one DFS domain
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* @domain: DFS regulatory domain
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* @num_radar_types: number of radar types to follow
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* @radar_types: radar types array
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*/
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struct radar_types {
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enum nl80211_dfs_regions region;
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u32 num_radar_types;
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const struct radar_detector_specs *radar_types;
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};
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/* percentage on ppb threshold to trigger detection */
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#define MIN_PPB_THRESH 50
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#define PPB_THRESH(PPB) ((PPB * MIN_PPB_THRESH + 50) / 100)
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#define PRF2PRI(PRF) ((1000000 + PRF / 2) / PRF)
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#define ETSI_PATTERN(ID, WMIN, WMAX, PMIN, PMAX, PRF, PPB) \
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{ \
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ID, WMIN, WMAX, (PRF2PRI(PMAX) - PRI_TOLERANCE), \
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(PRF2PRI(PMIN) * PRF + PRI_TOLERANCE), PRF, PPB * PRF, \
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PPB_THRESH(PPB), PRI_TOLERANCE, \
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}
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/* radar types as defined by ETSI EN-301-893 v1.5.1 */
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static const struct radar_detector_specs etsi_radar_ref_types_v15[] = {
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ETSI_PATTERN(0, 0, 1, 700, 700, 1, 18),
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ETSI_PATTERN(1, 0, 5, 200, 1000, 1, 10),
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ETSI_PATTERN(2, 0, 15, 200, 1600, 1, 15),
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ETSI_PATTERN(3, 0, 15, 2300, 4000, 1, 25),
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ETSI_PATTERN(4, 20, 30, 2000, 4000, 1, 20),
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ETSI_PATTERN(5, 0, 2, 300, 400, 3, 10),
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ETSI_PATTERN(6, 0, 2, 400, 1200, 3, 15),
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};
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static const struct radar_types etsi_radar_types_v15 = {
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.region = NL80211_DFS_ETSI,
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.num_radar_types = ARRAY_SIZE(etsi_radar_ref_types_v15),
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.radar_types = etsi_radar_ref_types_v15,
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};
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/* for now, we support ETSI radar types, FCC and JP are TODO */
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static const struct radar_types *dfs_domains[] = {
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&etsi_radar_types_v15,
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};
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/**
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* get_dfs_domain_radar_types() - get radar types for a given DFS domain
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* @param domain DFS domain
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* @return radar_types ptr on success, NULL if DFS domain is not supported
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*/
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static const struct radar_types *
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get_dfs_domain_radar_types(enum nl80211_dfs_regions region)
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{
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u32 i;
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for (i = 0; i < ARRAY_SIZE(dfs_domains); i++) {
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if (dfs_domains[i]->region == region)
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return dfs_domains[i];
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}
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return NULL;
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}
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/**
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* struct channel_detector - detector elements for a DFS channel
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* @head: list_head
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* @freq: frequency for this channel detector in MHz
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* @detectors: array of dynamically created detector elements for this freq
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*
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* Channel detectors are required to provide multi-channel DFS detection, e.g.
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* to support off-channel scanning. A pattern detector has a list of channels
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* radar pulses have been reported for in the past.
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*/
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struct channel_detector {
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struct list_head head;
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u16 freq;
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struct pri_detector **detectors;
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};
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/* channel_detector_reset() - reset detector lines for a given channel */
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static void channel_detector_reset(struct dfs_pattern_detector *dpd,
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struct channel_detector *cd)
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{
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u32 i;
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if (cd == NULL)
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return;
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for (i = 0; i < dpd->num_radar_types; i++)
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cd->detectors[i]->reset(cd->detectors[i], dpd->last_pulse_ts);
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}
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/* channel_detector_exit() - destructor */
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static void channel_detector_exit(struct dfs_pattern_detector *dpd,
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struct channel_detector *cd)
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{
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u32 i;
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if (cd == NULL)
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return;
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list_del(&cd->head);
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for (i = 0; i < dpd->num_radar_types; i++) {
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struct pri_detector *de = cd->detectors[i];
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if (de != NULL)
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de->exit(de);
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}
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kfree(cd->detectors);
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kfree(cd);
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}
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static struct channel_detector *
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channel_detector_create(struct dfs_pattern_detector *dpd, u16 freq)
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{
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u32 sz, i;
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struct channel_detector *cd;
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cd = kmalloc(sizeof(*cd), GFP_KERNEL);
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if (cd == NULL)
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goto fail;
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INIT_LIST_HEAD(&cd->head);
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cd->freq = freq;
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sz = sizeof(cd->detectors) * dpd->num_radar_types;
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cd->detectors = kzalloc(sz, GFP_KERNEL);
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if (cd->detectors == NULL)
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goto fail;
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for (i = 0; i < dpd->num_radar_types; i++) {
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const struct radar_detector_specs *rs = &dpd->radar_spec[i];
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struct pri_detector *de = pri_detector_init(rs);
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if (de == NULL)
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goto fail;
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cd->detectors[i] = de;
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}
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list_add(&cd->head, &dpd->channel_detectors);
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return cd;
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fail:
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pr_err("failed to allocate channel_detector for freq=%d\n", freq);
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channel_detector_exit(dpd, cd);
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return NULL;
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}
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/**
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* channel_detector_get() - get channel detector for given frequency
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* @param dpd instance pointer
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* @param freq frequency in MHz
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* @return pointer to channel detector on success, NULL otherwise
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*
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* Return existing channel detector for the given frequency or return a
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* newly create one.
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*/
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static struct channel_detector *
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channel_detector_get(struct dfs_pattern_detector *dpd, u16 freq)
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{
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struct channel_detector *cd;
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list_for_each_entry(cd, &dpd->channel_detectors, head) {
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if (cd->freq == freq)
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return cd;
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}
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return channel_detector_create(dpd, freq);
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}
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/*
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* DFS Pattern Detector
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*/
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/* dpd_reset(): reset all channel detectors */
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static void dpd_reset(struct dfs_pattern_detector *dpd)
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{
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struct channel_detector *cd;
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if (!list_empty(&dpd->channel_detectors))
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list_for_each_entry(cd, &dpd->channel_detectors, head)
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channel_detector_reset(dpd, cd);
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}
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static void dpd_exit(struct dfs_pattern_detector *dpd)
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{
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struct channel_detector *cd, *cd0;
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if (!list_empty(&dpd->channel_detectors))
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list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
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channel_detector_exit(dpd, cd);
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kfree(dpd);
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}
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static bool
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dpd_add_pulse(struct dfs_pattern_detector *dpd, struct pulse_event *event)
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{
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u32 i;
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bool ts_wraparound;
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struct channel_detector *cd;
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if (dpd->region == NL80211_DFS_UNSET) {
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/*
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* pulses received for a non-supported or un-initialized
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* domain are treated as detected radars
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*/
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return true;
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}
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cd = channel_detector_get(dpd, event->freq);
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if (cd == NULL)
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return false;
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ts_wraparound = (event->ts < dpd->last_pulse_ts);
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dpd->last_pulse_ts = event->ts;
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if (ts_wraparound) {
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/*
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* reset detector on time stamp wraparound
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* with monotonic time stamps, this should never happen
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*/
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pr_warn("DFS: time stamp wraparound detected, resetting\n");
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dpd_reset(dpd);
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}
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/* do type individual pattern matching */
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for (i = 0; i < dpd->num_radar_types; i++) {
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if (cd->detectors[i]->add_pulse(cd->detectors[i], event) != 0) {
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channel_detector_reset(dpd, cd);
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return true;
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}
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}
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return false;
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}
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static bool dpd_set_domain(struct dfs_pattern_detector *dpd,
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enum nl80211_dfs_regions region)
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{
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const struct radar_types *rt;
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struct channel_detector *cd, *cd0;
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if (dpd->region == region)
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return true;
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dpd->region = NL80211_DFS_UNSET;
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rt = get_dfs_domain_radar_types(region);
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if (rt == NULL)
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return false;
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/* delete all channel detectors for previous DFS domain */
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if (!list_empty(&dpd->channel_detectors))
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list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
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channel_detector_exit(dpd, cd);
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dpd->radar_spec = rt->radar_types;
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dpd->num_radar_types = rt->num_radar_types;
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dpd->region = region;
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return true;
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}
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static struct dfs_pattern_detector default_dpd = {
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.exit = dpd_exit,
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.set_domain = dpd_set_domain,
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.add_pulse = dpd_add_pulse,
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.region = NL80211_DFS_UNSET,
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};
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struct dfs_pattern_detector *
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dfs_pattern_detector_init(enum nl80211_dfs_regions region)
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{
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struct dfs_pattern_detector *dpd;
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dpd = kmalloc(sizeof(*dpd), GFP_KERNEL);
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if (dpd == NULL) {
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pr_err("allocation of dfs_pattern_detector failed\n");
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return NULL;
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}
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*dpd = default_dpd;
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INIT_LIST_HEAD(&dpd->channel_detectors);
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if (dpd->set_domain(dpd, region))
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return dpd;
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pr_err("Could not set DFS domain to %d. ", region);
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return NULL;
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}
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EXPORT_SYMBOL(dfs_pattern_detector_init);
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