drivers/net/wireless/ath/ath9k/dfs_pattern_detector.c - linux - Git at Google

 /*
  * 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/export.h>

 #include "dfs_pattern_detector.h"
 #include "dfs_pri_detector.h"

 /*
  * tolerated deviation of radar time stamp in usecs on both sides
  * TODO: this might need to be HW-dependent
  */
 #define PRI_TOLERANCE	16

 /**
  * struct radar_types - contains array of patterns defined for one DFS domain
  * @domain: DFS regulatory domain
  * @num_radar_types: number of radar types to follow
  * @radar_types: radar types array
  */
 struct radar_types {
 	enum nl80211_dfs_regions region;
 	u32 num_radar_types;
 	const struct radar_detector_specs *radar_types;
 };

 /* percentage on ppb threshold to trigger detection */
 #define MIN_PPB_THRESH	50
 #define PPB_THRESH(PPB) ((PPB * MIN_PPB_THRESH + 50) / 100)
 #define PRF2PRI(PRF) ((1000000 + PRF / 2) / PRF)
 /* percentage of pulse width tolerance */
 #define WIDTH_TOLERANCE 5
 #define WIDTH_LOWER(X) ((X*(100-WIDTH_TOLERANCE)+50)/100)
 #define WIDTH_UPPER(X) ((X*(100+WIDTH_TOLERANCE)+50)/100)

 #define ETSI_PATTERN(ID, WMIN, WMAX, PMIN, PMAX, PRF, PPB)	\
 {								\
 	ID, WIDTH_LOWER(WMIN), WIDTH_UPPER(WMAX),		\
 	(PRF2PRI(PMAX) - PRI_TOLERANCE),			\
 	(PRF2PRI(PMIN) * PRF + PRI_TOLERANCE), PRF, PPB * PRF,	\
 	PPB_THRESH(PPB), PRI_TOLERANCE,				\
 }

 /* radar types as defined by ETSI EN-301-893 v1.5.1 */
 static const struct radar_detector_specs etsi_radar_ref_types_v15[] = {
 	ETSI_PATTERN(0,  0,  1,  700,  700, 1, 18),
 	ETSI_PATTERN(1,  0,  5,  200, 1000, 1, 10),
 	ETSI_PATTERN(2,  0, 15,  200, 1600, 1, 15),
 	ETSI_PATTERN(3,  0, 15, 2300, 4000, 1, 25),
 	ETSI_PATTERN(4, 20, 30, 2000, 4000, 1, 20),
 	ETSI_PATTERN(5,  0,  2,  300,  400, 3, 10),
 	ETSI_PATTERN(6,  0,  2,  400, 1200, 3, 15),
 };

 static const struct radar_types etsi_radar_types_v15 = {
 	.region			= NL80211_DFS_ETSI,
 	.num_radar_types	= ARRAY_SIZE(etsi_radar_ref_types_v15),
 	.radar_types		= etsi_radar_ref_types_v15,
 };

 /* for now, we support ETSI radar types, FCC and JP are TODO */
 static const struct radar_types *dfs_domains[] = {
 	&etsi_radar_types_v15,
 };

 /**
  * get_dfs_domain_radar_types() - get radar types for a given DFS domain
  * @param domain DFS domain
  * @return radar_types ptr on success, NULL if DFS domain is not supported
  */
 static const struct radar_types *
 get_dfs_domain_radar_types(enum nl80211_dfs_regions region)
 {
 	u32 i;
 	for (i = 0; i < ARRAY_SIZE(dfs_domains); i++) {
 		if (dfs_domains[i]->region == region)
 			return dfs_domains[i];
 	}
 	return NULL;
 }

 /**
  * struct channel_detector - detector elements for a DFS channel
  * @head: list_head
  * @freq: frequency for this channel detector in MHz
  * @detectors: array of dynamically created detector elements for this freq
  *
  * Channel detectors are required to provide multi-channel DFS detection, e.g.
  * to support off-channel scanning. A pattern detector has a list of channels
  * radar pulses have been reported for in the past.
  */
 struct channel_detector {
 	struct list_head head;
 	u16 freq;
 	struct pri_detector **detectors;
 };

 /* channel_detector_reset() - reset detector lines for a given channel */
 static void channel_detector_reset(struct dfs_pattern_detector *dpd,
 				   struct channel_detector *cd)
 {
 	u32 i;
 	if (cd == NULL)
 		return;
 	for (i = 0; i < dpd->num_radar_types; i++)
 		cd->detectors[i]->reset(cd->detectors[i], dpd->last_pulse_ts);
 }

 /* channel_detector_exit() - destructor */
 static void channel_detector_exit(struct dfs_pattern_detector *dpd,
 				  struct channel_detector *cd)
 {
 	u32 i;
 	if (cd == NULL)
 		return;
 	list_del(&cd->head);
 	for (i = 0; i < dpd->num_radar_types; i++) {
 		struct pri_detector *de = cd->detectors[i];
 		if (de != NULL)
 			de->exit(de);
 	}
 	kfree(cd->detectors);
 	kfree(cd);
 }

 static struct channel_detector *
 channel_detector_create(struct dfs_pattern_detector *dpd, u16 freq)
 {
 	u32 sz, i;
 	struct channel_detector *cd;

 	cd = kmalloc(sizeof(*cd), GFP_KERNEL);
 	if (cd == NULL)
 		goto fail;

 	INIT_LIST_HEAD(&cd->head);
 	cd->freq = freq;
 	sz = sizeof(cd->detectors) * dpd->num_radar_types;
 	cd->detectors = kzalloc(sz, GFP_KERNEL);
 	if (cd->detectors == NULL)
 		goto fail;

 	for (i = 0; i < dpd->num_radar_types; i++) {
 		const struct radar_detector_specs *rs = &dpd->radar_spec[i];
 		struct pri_detector *de = pri_detector_init(rs);
 		if (de == NULL)
 			goto fail;
 		cd->detectors[i] = de;
 	}
 	list_add(&cd->head, &dpd->channel_detectors);
 	return cd;

 fail:
 	pr_err("failed to allocate channel_detector for freq=%d\n", freq);
 	channel_detector_exit(dpd, cd);
 	return NULL;
 }

 /**
  * channel_detector_get() - get channel detector for given frequency
  * @param dpd instance pointer
  * @param freq frequency in MHz
  * @return pointer to channel detector on success, NULL otherwise
  *
  * Return existing channel detector for the given frequency or return a
  * newly create one.
  */
 static struct channel_detector *
 channel_detector_get(struct dfs_pattern_detector *dpd, u16 freq)
 {
 	struct channel_detector *cd;
 	list_for_each_entry(cd, &dpd->channel_detectors, head) {
 		if (cd->freq == freq)
 			return cd;
 	}
 	return channel_detector_create(dpd, freq);
 }

 /*
  * DFS Pattern Detector
  */

 /* dpd_reset(): reset all channel detectors */
 static void dpd_reset(struct dfs_pattern_detector *dpd)
 {
 	struct channel_detector *cd;
 	if (!list_empty(&dpd->channel_detectors))
 		list_for_each_entry(cd, &dpd->channel_detectors, head)
 			channel_detector_reset(dpd, cd);

 }
 static void dpd_exit(struct dfs_pattern_detector *dpd)
 {
 	struct channel_detector *cd, *cd0;
 	if (!list_empty(&dpd->channel_detectors))
 		list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
 			channel_detector_exit(dpd, cd);
 	kfree(dpd);
 }

 static bool
 dpd_add_pulse(struct dfs_pattern_detector *dpd, struct pulse_event *event)
 {
 	u32 i;
 	bool ts_wraparound;
 	struct channel_detector *cd;

 	if (dpd->region == NL80211_DFS_UNSET) {
 		/*
 		 * pulses received for a non-supported or un-initialized
 		 * domain are treated as detected radars
 		 */
 		return true;
 	}

 	cd = channel_detector_get(dpd, event->freq);
 	if (cd == NULL)
 		return false;

 	ts_wraparound = (event->ts < dpd->last_pulse_ts);
 	dpd->last_pulse_ts = event->ts;
 	if (ts_wraparound) {
 		/*
 		 * reset detector on time stamp wraparound
 		 * with monotonic time stamps, this should never happen
 		 */
 		pr_warn("DFS: time stamp wraparound detected, resetting\n");
 		dpd_reset(dpd);
 	}
 	/* do type individual pattern matching */
 	for (i = 0; i < dpd->num_radar_types; i++) {
 		if (cd->detectors[i]->add_pulse(cd->detectors[i], event) != 0) {
 			channel_detector_reset(dpd, cd);
 			return true;
 		}
 	}
 	return false;
 }

 static bool dpd_set_domain(struct dfs_pattern_detector *dpd,
 			   enum nl80211_dfs_regions region)
 {
 	const struct radar_types *rt;
 	struct channel_detector *cd, *cd0;

 	if (dpd->region == region)
 		return true;

 	dpd->region = NL80211_DFS_UNSET;

 	rt = get_dfs_domain_radar_types(region);
 	if (rt == NULL)
 		return false;

 	/* delete all channel detectors for previous DFS domain */
 	if (!list_empty(&dpd->channel_detectors))
 		list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
 			channel_detector_exit(dpd, cd);
 	dpd->radar_spec = rt->radar_types;
 	dpd->num_radar_types = rt->num_radar_types;

 	dpd->region = region;
 	return true;
 }

 static struct dfs_pattern_detector default_dpd = {
 	.exit		= dpd_exit,
 	.set_dfs_domain	= dpd_set_domain,
 	.add_pulse	= dpd_add_pulse,
 	.region		= NL80211_DFS_UNSET,
 };

 struct dfs_pattern_detector *
 dfs_pattern_detector_init(enum nl80211_dfs_regions region)
 {
 	struct dfs_pattern_detector *dpd;

 	dpd = kmalloc(sizeof(*dpd), GFP_KERNEL);
 	if (dpd == NULL)
 		return NULL;

 	*dpd = default_dpd;
 	INIT_LIST_HEAD(&dpd->channel_detectors);

 	if (dpd->set_dfs_domain(dpd, region))
 		return dpd;

 	pr_err("Could not set DFS domain to %d. ", region);
 	kfree(dpd);
 	return NULL;
 }
 EXPORT_SYMBOL(dfs_pattern_detector_init);
	/*
	* 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/export.h>

	#include "dfs_pattern_detector.h"
	#include "dfs_pri_detector.h"

	/*
	* tolerated deviation of radar time stamp in usecs on both sides
	* TODO: this might need to be HW-dependent
	*/
	#define PRI_TOLERANCE 16

	/**
	* struct radar_types - contains array of patterns defined for one DFS domain
	* @domain: DFS regulatory domain
	* @num_radar_types: number of radar types to follow
	* @radar_types: radar types array
	*/
	struct radar_types {
	enum nl80211_dfs_regions region;
	u32 num_radar_types;
	const struct radar_detector_specs *radar_types;
	};

	/* percentage on ppb threshold to trigger detection */
	#define MIN_PPB_THRESH 50
	#define PPB_THRESH(PPB) ((PPB * MIN_PPB_THRESH + 50) / 100)
	#define PRF2PRI(PRF) ((1000000 + PRF / 2) / PRF)
	/* percentage of pulse width tolerance */
	#define WIDTH_TOLERANCE 5
	#define WIDTH_LOWER(X) ((X*(100-WIDTH_TOLERANCE)+50)/100)
	#define WIDTH_UPPER(X) ((X*(100+WIDTH_TOLERANCE)+50)/100)

	#define ETSI_PATTERN(ID, WMIN, WMAX, PMIN, PMAX, PRF, PPB) \
	{ \
	ID, WIDTH_LOWER(WMIN), WIDTH_UPPER(WMAX), \
	(PRF2PRI(PMAX) - PRI_TOLERANCE), \
	(PRF2PRI(PMIN) * PRF + PRI_TOLERANCE), PRF, PPB * PRF, \
	PPB_THRESH(PPB), PRI_TOLERANCE, \
	}

	/* radar types as defined by ETSI EN-301-893 v1.5.1 */
	static const struct radar_detector_specs etsi_radar_ref_types_v15[] = {
	ETSI_PATTERN(0, 0, 1, 700, 700, 1, 18),
	ETSI_PATTERN(1, 0, 5, 200, 1000, 1, 10),
	ETSI_PATTERN(2, 0, 15, 200, 1600, 1, 15),
	ETSI_PATTERN(3, 0, 15, 2300, 4000, 1, 25),
	ETSI_PATTERN(4, 20, 30, 2000, 4000, 1, 20),
	ETSI_PATTERN(5, 0, 2, 300, 400, 3, 10),
	ETSI_PATTERN(6, 0, 2, 400, 1200, 3, 15),
	};

	static const struct radar_types etsi_radar_types_v15 = {
	.region = NL80211_DFS_ETSI,
	.num_radar_types = ARRAY_SIZE(etsi_radar_ref_types_v15),
	.radar_types = etsi_radar_ref_types_v15,
	};

	/* for now, we support ETSI radar types, FCC and JP are TODO */
	static const struct radar_types *dfs_domains[] = {
	&etsi_radar_types_v15,
	};

	/**
	* get_dfs_domain_radar_types() - get radar types for a given DFS domain
	* @param domain DFS domain
	* @return radar_types ptr on success, NULL if DFS domain is not supported
	*/
	static const struct radar_types *
	get_dfs_domain_radar_types(enum nl80211_dfs_regions region)
	{
	u32 i;
	for (i = 0; i < ARRAY_SIZE(dfs_domains); i++) {
	if (dfs_domains[i]->region == region)
	return dfs_domains[i];
	}
	return NULL;
	}

	/**
	* struct channel_detector - detector elements for a DFS channel
	* @head: list_head
	* @freq: frequency for this channel detector in MHz
	* @detectors: array of dynamically created detector elements for this freq
	*
	* Channel detectors are required to provide multi-channel DFS detection, e.g.
	* to support off-channel scanning. A pattern detector has a list of channels
	* radar pulses have been reported for in the past.
	*/
	struct channel_detector {
	struct list_head head;
	u16 freq;
	struct pri_detector **detectors;
	};

	/* channel_detector_reset() - reset detector lines for a given channel */
	static void channel_detector_reset(struct dfs_pattern_detector *dpd,
	struct channel_detector *cd)
	{
	u32 i;
	if (cd == NULL)
	return;
	for (i = 0; i < dpd->num_radar_types; i++)
	cd->detectors[i]->reset(cd->detectors[i], dpd->last_pulse_ts);
	}

	/* channel_detector_exit() - destructor */
	static void channel_detector_exit(struct dfs_pattern_detector *dpd,
	struct channel_detector *cd)
	{
	u32 i;
	if (cd == NULL)
	return;
	list_del(&cd->head);
	for (i = 0; i < dpd->num_radar_types; i++) {
	struct pri_detector *de = cd->detectors[i];
	if (de != NULL)
	de->exit(de);
	}
	kfree(cd->detectors);
	kfree(cd);
	}

	static struct channel_detector *
	channel_detector_create(struct dfs_pattern_detector *dpd, u16 freq)
	{
	u32 sz, i;
	struct channel_detector *cd;

	cd = kmalloc(sizeof(*cd), GFP_KERNEL);
	if (cd == NULL)
	goto fail;

	INIT_LIST_HEAD(&cd->head);
	cd->freq = freq;
	sz = sizeof(cd->detectors) * dpd->num_radar_types;
	cd->detectors = kzalloc(sz, GFP_KERNEL);
	if (cd->detectors == NULL)
	goto fail;

	for (i = 0; i < dpd->num_radar_types; i++) {
	const struct radar_detector_specs *rs = &dpd->radar_spec[i];
	struct pri_detector *de = pri_detector_init(rs);
	if (de == NULL)
	goto fail;
	cd->detectors[i] = de;
	}
	list_add(&cd->head, &dpd->channel_detectors);
	return cd;

	fail:
	pr_err("failed to allocate channel_detector for freq=%d\n", freq);
	channel_detector_exit(dpd, cd);
	return NULL;
	}

	/**
	* channel_detector_get() - get channel detector for given frequency
	* @param dpd instance pointer
	* @param freq frequency in MHz
	* @return pointer to channel detector on success, NULL otherwise
	*
	* Return existing channel detector for the given frequency or return a
	* newly create one.
	*/
	static struct channel_detector *
	channel_detector_get(struct dfs_pattern_detector *dpd, u16 freq)
	{
	struct channel_detector *cd;
	list_for_each_entry(cd, &dpd->channel_detectors, head) {
	if (cd->freq == freq)
	return cd;
	}
	return channel_detector_create(dpd, freq);
	}

	/*
	* DFS Pattern Detector
	*/

	/* dpd_reset(): reset all channel detectors */
	static void dpd_reset(struct dfs_pattern_detector *dpd)
	{
	struct channel_detector *cd;
	if (!list_empty(&dpd->channel_detectors))
	list_for_each_entry(cd, &dpd->channel_detectors, head)
	channel_detector_reset(dpd, cd);

	}
	static void dpd_exit(struct dfs_pattern_detector *dpd)
	{
	struct channel_detector cd, cd0;
	if (!list_empty(&dpd->channel_detectors))
	list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
	channel_detector_exit(dpd, cd);
	kfree(dpd);
	}

	static bool
	dpd_add_pulse(struct dfs_pattern_detector dpd, struct pulse_event event)
	{
	u32 i;
	bool ts_wraparound;
	struct channel_detector *cd;

	if (dpd->region == NL80211_DFS_UNSET) {
	/*
	* pulses received for a non-supported or un-initialized
	* domain are treated as detected radars
	*/
	return true;
	}

	cd = channel_detector_get(dpd, event->freq);
	if (cd == NULL)
	return false;

	ts_wraparound = (event->ts < dpd->last_pulse_ts);
	dpd->last_pulse_ts = event->ts;
	if (ts_wraparound) {
	/*
	* reset detector on time stamp wraparound
	* with monotonic time stamps, this should never happen
	*/
	pr_warn("DFS: time stamp wraparound detected, resetting\n");
	dpd_reset(dpd);
	}
	/* do type individual pattern matching */
	for (i = 0; i < dpd->num_radar_types; i++) {
	if (cd->detectors[i]->add_pulse(cd->detectors[i], event) != 0) {
	channel_detector_reset(dpd, cd);
	return true;
	}
	}
	return false;
	}

	static bool dpd_set_domain(struct dfs_pattern_detector *dpd,
	enum nl80211_dfs_regions region)
	{
	const struct radar_types *rt;
	struct channel_detector cd, cd0;

	if (dpd->region == region)
	return true;

	dpd->region = NL80211_DFS_UNSET;

	rt = get_dfs_domain_radar_types(region);
	if (rt == NULL)
	return false;

	/* delete all channel detectors for previous DFS domain */
	if (!list_empty(&dpd->channel_detectors))
	list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
	channel_detector_exit(dpd, cd);
	dpd->radar_spec = rt->radar_types;
	dpd->num_radar_types = rt->num_radar_types;

	dpd->region = region;
	return true;
	}

	static struct dfs_pattern_detector default_dpd = {
	.exit = dpd_exit,
	.set_dfs_domain = dpd_set_domain,
	.add_pulse = dpd_add_pulse,
	.region = NL80211_DFS_UNSET,
	};

	struct dfs_pattern_detector *
	dfs_pattern_detector_init(enum nl80211_dfs_regions region)
	{
	struct dfs_pattern_detector *dpd;

	dpd = kmalloc(sizeof(*dpd), GFP_KERNEL);
	if (dpd == NULL)
	return NULL;

	*dpd = default_dpd;
	INIT_LIST_HEAD(&dpd->channel_detectors);

	if (dpd->set_dfs_domain(dpd, region))
	return dpd;

	pr_err("Could not set DFS domain to %d. ", region);
	kfree(dpd);
	return NULL;
	}
	EXPORT_SYMBOL(dfs_pattern_detector_init);