ath9k/ath: move dfs pattern detector to ath

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>

1 files changed, 320 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/dfs_pattern_detector.c b/drivers/net/wireless/ath/dfs_pattern_detector.c
new file mode 100644
index 000000000000..a1a69c5db409
--- /dev/null
+++ b/drivers/net/wireless/ath/dfs_pattern_detector.c
@@ -0,0 +1,320 @@
+/*
+ * 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"
+
+/*
+ * 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_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)
+{
+	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;
+
+	dpd->last_pulse_ts = event->ts;
+	/* reset detector on time stamp wraparound, caused by TSF reset */
+	if (event->ts < dpd->last_pulse_ts)
+		dpd_reset(dpd);
+
+	/* 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) {
+			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);
+			channel_detector_reset(dpd, cd);
+			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 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 (!config_enabled(CONFIG_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);