text: /*
   * 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"
  #include "ath.h"
  
  /**
   * 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_RATE(PPB, RATE) ((PPB * RATE + 100 - RATE) / 100)
  #define PPB_THRESH(PPB) PPB_THRESH_RATE(PPB, MIN_PPB_THRESH)
  #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, CHIRP)	\
  {								\
  	ID, WIDTH_LOWER(WMIN), WIDTH_UPPER(WMAX),		\
  	(PRF2PRI(PMAX) - PRI_TOLERANCE),			\
  	(PRF2PRI(PMIN) * PRF + PRI_TOLERANCE), PRF, PPB * PRF,	\
  	PPB_THRESH(PPB), PRI_TOLERANCE,	CHIRP			\
  }
  
  /* 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, false),
  	ETSI_PATTERN(1,  0,  5,  200, 1000, 1, 10, false),
  	ETSI_PATTERN(2,  0, 15,  200, 1600, 1, 15, false),
  	ETSI_PATTERN(3,  0, 15, 2300, 4000, 1, 25, false),
  	ETSI_PATTERN(4, 20, 30, 2000, 4000, 1, 20, false),
  	ETSI_PATTERN(5,  0,  2,  300,  400, 3, 10, false),
  	ETSI_PATTERN(6,  0,  2,  400, 1200, 3, 15, false),
  };
  
  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,
  };
  
  #define FCC_PATTERN(ID, WMIN, WMAX, PMIN, PMAX, PRF, PPB, CHIRP)	\
  {								\
  	ID, WIDTH_LOWER(WMIN), WIDTH_UPPER(WMAX),		\
  	PMIN - PRI_TOLERANCE,					\
  	PMAX * PRF + PRI_TOLERANCE, PRF, PPB * PRF,		\
  	PPB_THRESH(PPB), PRI_TOLERANCE,	CHIRP			\
  }
  
  /* radar types released on August 14, 2014
   * type 1 PRI values randomly selected within the range of 518 and 3066.
   * divide it to 3 groups is good enough for both of radar detection and
   * avoiding false detection based on practical test results
   * collected for more than a year.
   */
  static const struct radar_detector_specs fcc_radar_ref_types[] = {
  	FCC_PATTERN(0, 0, 1, 1428, 1428, 1, 18, false),
  	FCC_PATTERN(101, 0, 1, 518, 938, 1, 57, false),
  	FCC_PATTERN(102, 0, 1, 938, 2000, 1, 27, false),
  	FCC_PATTERN(103, 0, 1, 2000, 3066, 1, 18, false),
  	FCC_PATTERN(2, 0, 5, 150, 230, 1, 23, false),
  	FCC_PATTERN(3, 6, 10, 200, 500, 1, 16, false),
  	FCC_PATTERN(4, 11, 20, 200, 500, 1, 12, false),
  	FCC_PATTERN(5, 50, 100, 1000, 2000, 1, 1, true),
  	FCC_PATTERN(6, 0, 1, 333, 333, 1, 9, false),
  };
  
  static const struct radar_types fcc_radar_types = {
  	.region			= NL80211_DFS_FCC,
  	.num_radar_types	= ARRAY_SIZE(fcc_radar_ref_types),
  	.radar_types		= fcc_radar_ref_types,
  };
  
  #define JP_PATTERN(ID, WMIN, WMAX, PMIN, PMAX, PRF, PPB, RATE, CHIRP)	\
  {								\
  	ID, WIDTH_LOWER(WMIN), WIDTH_UPPER(WMAX),		\
  	PMIN - PRI_TOLERANCE,					\
  	PMAX * PRF + PRI_TOLERANCE, PRF, PPB * PRF,		\
  	PPB_THRESH_RATE(PPB, RATE), PRI_TOLERANCE, CHIRP	\
  }
  static const struct radar_detector_specs jp_radar_ref_types[] = {
  	JP_PATTERN(0, 0, 1, 1428, 1428, 1, 18, 29, false),
  	JP_PATTERN(1, 2, 3, 3846, 3846, 1, 18, 29, false),
  	JP_PATTERN(2, 0, 1, 1388, 1388, 1, 18, 50, false),
  	JP_PATTERN(3, 0, 4, 4000, 4000, 1, 18, 50, false),
  	JP_PATTERN(4, 0, 5, 150, 230, 1, 23, 50, false),
  	JP_PATTERN(5, 6, 10, 200, 500, 1, 16, 50, false),
  	JP_PATTERN(6, 11, 20, 200, 500, 1, 12, 50, false),
  	JP_PATTERN(7, 50, 100, 1000, 2000, 1, 3, 50, true),
  	JP_PATTERN(5, 0, 1, 333, 333, 1, 9, 50, false),
  };
  
  static const struct radar_types jp_radar_types = {
  	.region			= NL80211_DFS_JP,
  	.num_radar_types	= ARRAY_SIZE(jp_radar_ref_types),
  	.radar_types		= jp_radar_ref_types,
  };
  
  static const struct radar_types *dfs_domains[] = {
  	&etsi_radar_types_v15,
  	&fcc_radar_types,
  	&jp_radar_types,
  };
  
  /**
   * 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_ATOMIC);
  	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_ATOMIC);
  	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:
  	ath_dbg(dpd->common, DFS,
  		"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,
  	      struct radar_detector_specs *rs)
  {
  	u32 i;
  	struct channel_detector *cd;
  
  	/*
  	 * pulses received for a non-supported or un-initialized
  	 * domain are treated as detected radars for fail-safety
  	 */
  	if (dpd->region == NL80211_DFS_UNSET)
  		return true;
  
  	cd = channel_detector_get(dpd, event->freq);
  	if (cd == NULL)
  		return false;
  
  	/* reset detector on time stamp wraparound, caused by TSF reset */
  	if (event->ts < dpd->last_pulse_ts)
  		dpd_reset(dpd);
  	dpd->last_pulse_ts = event->ts;
  
  	/* do type individual pattern matching */
  	for (i = 0; i < dpd->num_radar_types; i++) {
  		struct pri_detector *pd = cd->detectors[i];
  		struct pri_sequence *ps = pd->add_pulse(pd, event);
  		if (ps != NULL) {
  			if (rs != NULL)
  				memcpy(rs, pd->rs, sizeof(*rs));
  			ath_dbg(dpd->common, DFS,
  				"DFS: radar found on freq=%d: id=%d, pri=%d, "
  				"count=%d, count_false=%d\n",
  				event->freq, pd->rs->type_id,
  				ps->pri, ps->count, ps->count_falses);
  			pd->reset(pd, dpd->last_pulse_ts);
  			return true;
  		}
  	}
  	return false;
  }
  
  static struct ath_dfs_pool_stats
  dpd_get_stats(struct dfs_pattern_detector *dpd)
  {
  	return global_dfs_pool_stats;
  }
  
  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 const struct dfs_pattern_detector default_dpd = {
  	.exit		= dpd_exit,
  	.set_dfs_domain	= dpd_set_domain,
  	.add_pulse	= dpd_add_pulse,
  	.get_stats	= dpd_get_stats,
  	.region		= NL80211_DFS_UNSET,
  };
  
  struct dfs_pattern_detector *
  dfs_pattern_detector_init(struct ath_common *common,
  			  enum nl80211_dfs_regions region)
  {
  	struct dfs_pattern_detector *dpd;
  
  	if (!IS_ENABLED(CPTCFG_CFG80211_CERTIFICATION_ONUS))
  		return NULL;
  
  	dpd = kmalloc(sizeof(*dpd), GFP_KERNEL);
  	if (dpd == NULL)
  		return NULL;
  
  	*dpd = default_dpd;
  	INIT_LIST_HEAD(&dpd->channel_detectors);
  
  	dpd->common = common;
  	if (dpd->set_dfs_domain(dpd, region))
  		return dpd;
  
  	ath_dbg(common, DFS,"Could not set DFS domain to %d", region);
  	kfree(dpd);
  	return NULL;
  }
  EXPORT_SYMBOL(dfs_pattern_detector_init);
  