1/*
2 * Copyright (c) 2012 Neratec Solutions AG
3 *
4 * Permission to use, copy, modify, and/or distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 */
16
17#include <linux/slab.h>
18#include <linux/export.h>
19
20#include "dfs_pattern_detector.h"
21#include "dfs_pri_detector.h"
22#include "ath.h"
23
24/*
25 * tolerated deviation of radar time stamp in usecs on both sides
26 * TODO: this might need to be HW-dependent
27 */
28#define PRI_TOLERANCE	16
29
30/**
31 * struct radar_types - contains array of patterns defined for one DFS domain
32 * @domain: DFS regulatory domain
33 * @num_radar_types: number of radar types to follow
34 * @radar_types: radar types array
35 */
36struct radar_types {
37	enum nl80211_dfs_regions region;
38	u32 num_radar_types;
39	const struct radar_detector_specs *radar_types;
40};
41
42/* percentage on ppb threshold to trigger detection */
43#define MIN_PPB_THRESH	50
44#define PPB_THRESH(PPB) ((PPB * MIN_PPB_THRESH + 50) / 100)
45#define PRF2PRI(PRF) ((1000000 + PRF / 2) / PRF)
46/* percentage of pulse width tolerance */
47#define WIDTH_TOLERANCE 5
48#define WIDTH_LOWER(X) ((X*(100-WIDTH_TOLERANCE)+50)/100)
49#define WIDTH_UPPER(X) ((X*(100+WIDTH_TOLERANCE)+50)/100)
50
51#define ETSI_PATTERN(ID, WMIN, WMAX, PMIN, PMAX, PRF, PPB)	\
52{								\
53	ID, WIDTH_LOWER(WMIN), WIDTH_UPPER(WMAX),		\
54	(PRF2PRI(PMAX) - PRI_TOLERANCE),			\
55	(PRF2PRI(PMIN) * PRF + PRI_TOLERANCE), PRF, PPB * PRF,	\
56	PPB_THRESH(PPB), PRI_TOLERANCE,				\
57}
58
59/* radar types as defined by ETSI EN-301-893 v1.5.1 */
60static const struct radar_detector_specs etsi_radar_ref_types_v15[] = {
61	ETSI_PATTERN(0,  0,  1,  700,  700, 1, 18),
62	ETSI_PATTERN(1,  0,  5,  200, 1000, 1, 10),
63	ETSI_PATTERN(2,  0, 15,  200, 1600, 1, 15),
64	ETSI_PATTERN(3,  0, 15, 2300, 4000, 1, 25),
65	ETSI_PATTERN(4, 20, 30, 2000, 4000, 1, 20),
66	ETSI_PATTERN(5,  0,  2,  300,  400, 3, 10),
67	ETSI_PATTERN(6,  0,  2,  400, 1200, 3, 15),
68};
69
70static const struct radar_types etsi_radar_types_v15 = {
71	.region			= NL80211_DFS_ETSI,
72	.num_radar_types	= ARRAY_SIZE(etsi_radar_ref_types_v15),
73	.radar_types		= etsi_radar_ref_types_v15,
74};
75
76#define FCC_PATTERN(ID, WMIN, WMAX, PMIN, PMAX, PRF, PPB)	\
77{								\
78	ID, WIDTH_LOWER(WMIN), WIDTH_UPPER(WMAX),		\
79	PMIN - PRI_TOLERANCE,					\
80	PMAX * PRF + PRI_TOLERANCE, PRF, PPB * PRF,		\
81	PPB_THRESH(PPB), PRI_TOLERANCE,				\
82}
83
84static const struct radar_detector_specs fcc_radar_ref_types[] = {
85	FCC_PATTERN(0, 0, 1, 1428, 1428, 1, 18),
86	FCC_PATTERN(1, 0, 5, 150, 230, 1, 23),
87	FCC_PATTERN(2, 6, 10, 200, 500, 1, 16),
88	FCC_PATTERN(3, 11, 20, 200, 500, 1, 12),
89	FCC_PATTERN(4, 50, 100, 1000, 2000, 20, 1),
90	FCC_PATTERN(5, 0, 1, 333, 333, 1, 9),
91};
92
93static const struct radar_types fcc_radar_types = {
94	.region			= NL80211_DFS_FCC,
95	.num_radar_types	= ARRAY_SIZE(fcc_radar_ref_types),
96	.radar_types		= fcc_radar_ref_types,
97};
98
99#define JP_PATTERN FCC_PATTERN
100static const struct radar_detector_specs jp_radar_ref_types[] = {
101	JP_PATTERN(0, 0, 1, 1428, 1428, 1, 18),
102	JP_PATTERN(1, 2, 3, 3846, 3846, 1, 18),
103	JP_PATTERN(2, 0, 1, 1388, 1388, 1, 18),
104	JP_PATTERN(3, 1, 2, 4000, 4000, 1, 18),
105	JP_PATTERN(4, 0, 5, 150, 230, 1, 23),
106	JP_PATTERN(5, 6, 10, 200, 500, 1, 16),
107	JP_PATTERN(6, 11, 20, 200, 500, 1, 12),
108	JP_PATTERN(7, 50, 100, 1000, 2000, 20, 1),
109	JP_PATTERN(5, 0, 1, 333, 333, 1, 9),
110};
111
112static const struct radar_types jp_radar_types = {
113	.region			= NL80211_DFS_JP,
114	.num_radar_types	= ARRAY_SIZE(jp_radar_ref_types),
115	.radar_types		= jp_radar_ref_types,
116};
117
118static const struct radar_types *dfs_domains[] = {
119	&etsi_radar_types_v15,
120	&fcc_radar_types,
121	&jp_radar_types,
122};
123
124/**
125 * get_dfs_domain_radar_types() - get radar types for a given DFS domain
126 * @param domain DFS domain
127 * @return radar_types ptr on success, NULL if DFS domain is not supported
128 */
129static const struct radar_types *
130get_dfs_domain_radar_types(enum nl80211_dfs_regions region)
131{
132	u32 i;
133	for (i = 0; i < ARRAY_SIZE(dfs_domains); i++) {
134		if (dfs_domains[i]->region == region)
135			return dfs_domains[i];
136	}
137	return NULL;
138}
139
140/**
141 * struct channel_detector - detector elements for a DFS channel
142 * @head: list_head
143 * @freq: frequency for this channel detector in MHz
144 * @detectors: array of dynamically created detector elements for this freq
145 *
146 * Channel detectors are required to provide multi-channel DFS detection, e.g.
147 * to support off-channel scanning. A pattern detector has a list of channels
148 * radar pulses have been reported for in the past.
149 */
150struct channel_detector {
151	struct list_head head;
152	u16 freq;
153	struct pri_detector **detectors;
154};
155
156/* channel_detector_reset() - reset detector lines for a given channel */
157static void channel_detector_reset(struct dfs_pattern_detector *dpd,
158				   struct channel_detector *cd)
159{
160	u32 i;
161	if (cd == NULL)
162		return;
163	for (i = 0; i < dpd->num_radar_types; i++)
164		cd->detectors[i]->reset(cd->detectors[i], dpd->last_pulse_ts);
165}
166
167/* channel_detector_exit() - destructor */
168static void channel_detector_exit(struct dfs_pattern_detector *dpd,
169				  struct channel_detector *cd)
170{
171	u32 i;
172	if (cd == NULL)
173		return;
174	list_del(&cd->head);
175	for (i = 0; i < dpd->num_radar_types; i++) {
176		struct pri_detector *de = cd->detectors[i];
177		if (de != NULL)
178			de->exit(de);
179	}
180	kfree(cd->detectors);
181	kfree(cd);
182}
183
184static struct channel_detector *
185channel_detector_create(struct dfs_pattern_detector *dpd, u16 freq)
186{
187	u32 sz, i;
188	struct channel_detector *cd;
189
190	cd = kmalloc(sizeof(*cd), GFP_ATOMIC);
191	if (cd == NULL)
192		goto fail;
193
194	INIT_LIST_HEAD(&cd->head);
195	cd->freq = freq;
196	sz = sizeof(cd->detectors) * dpd->num_radar_types;
197	cd->detectors = kzalloc(sz, GFP_ATOMIC);
198	if (cd->detectors == NULL)
199		goto fail;
200
201	for (i = 0; i < dpd->num_radar_types; i++) {
202		const struct radar_detector_specs *rs = &dpd->radar_spec[i];
203		struct pri_detector *de = pri_detector_init(rs);
204		if (de == NULL)
205			goto fail;
206		cd->detectors[i] = de;
207	}
208	list_add(&cd->head, &dpd->channel_detectors);
209	return cd;
210
211fail:
212	ath_dbg(dpd->common, DFS,
213		"failed to allocate channel_detector for freq=%d\n", freq);
214	channel_detector_exit(dpd, cd);
215	return NULL;
216}
217
218/**
219 * channel_detector_get() - get channel detector for given frequency
220 * @param dpd instance pointer
221 * @param freq frequency in MHz
222 * @return pointer to channel detector on success, NULL otherwise
223 *
224 * Return existing channel detector for the given frequency or return a
225 * newly create one.
226 */
227static struct channel_detector *
228channel_detector_get(struct dfs_pattern_detector *dpd, u16 freq)
229{
230	struct channel_detector *cd;
231	list_for_each_entry(cd, &dpd->channel_detectors, head) {
232		if (cd->freq == freq)
233			return cd;
234	}
235	return channel_detector_create(dpd, freq);
236}
237
238/*
239 * DFS Pattern Detector
240 */
241
242/* dpd_reset(): reset all channel detectors */
243static void dpd_reset(struct dfs_pattern_detector *dpd)
244{
245	struct channel_detector *cd;
246	if (!list_empty(&dpd->channel_detectors))
247		list_for_each_entry(cd, &dpd->channel_detectors, head)
248			channel_detector_reset(dpd, cd);
249
250}
251static void dpd_exit(struct dfs_pattern_detector *dpd)
252{
253	struct channel_detector *cd, *cd0;
254	if (!list_empty(&dpd->channel_detectors))
255		list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
256			channel_detector_exit(dpd, cd);
257	kfree(dpd);
258}
259
260static bool
261dpd_add_pulse(struct dfs_pattern_detector *dpd, struct pulse_event *event)
262{
263	u32 i;
264	struct channel_detector *cd;
265
266	/*
267	 * pulses received for a non-supported or un-initialized
268	 * domain are treated as detected radars for fail-safety
269	 */
270	if (dpd->region == NL80211_DFS_UNSET)
271		return true;
272
273	cd = channel_detector_get(dpd, event->freq);
274	if (cd == NULL)
275		return false;
276
277	dpd->last_pulse_ts = event->ts;
278	/* reset detector on time stamp wraparound, caused by TSF reset */
279	if (event->ts < dpd->last_pulse_ts)
280		dpd_reset(dpd);
281
282	/* do type individual pattern matching */
283	for (i = 0; i < dpd->num_radar_types; i++) {
284		struct pri_detector *pd = cd->detectors[i];
285		struct pri_sequence *ps = pd->add_pulse(pd, event);
286		if (ps != NULL) {
287			ath_dbg(dpd->common, DFS,
288				"DFS: radar found on freq=%d: id=%d, pri=%d, "
289				"count=%d, count_false=%d\n",
290				event->freq, pd->rs->type_id,
291				ps->pri, ps->count, ps->count_falses);
292			channel_detector_reset(dpd, cd);
293			return true;
294		}
295	}
296	return false;
297}
298
299static struct ath_dfs_pool_stats
300dpd_get_stats(struct dfs_pattern_detector *dpd)
301{
302	return global_dfs_pool_stats;
303}
304
305static bool dpd_set_domain(struct dfs_pattern_detector *dpd,
306			   enum nl80211_dfs_regions region)
307{
308	const struct radar_types *rt;
309	struct channel_detector *cd, *cd0;
310
311	if (dpd->region == region)
312		return true;
313
314	dpd->region = NL80211_DFS_UNSET;
315
316	rt = get_dfs_domain_radar_types(region);
317	if (rt == NULL)
318		return false;
319
320	/* delete all channel detectors for previous DFS domain */
321	if (!list_empty(&dpd->channel_detectors))
322		list_for_each_entry_safe(cd, cd0, &dpd->channel_detectors, head)
323			channel_detector_exit(dpd, cd);
324	dpd->radar_spec = rt->radar_types;
325	dpd->num_radar_types = rt->num_radar_types;
326
327	dpd->region = region;
328	return true;
329}
330
331static struct dfs_pattern_detector default_dpd = {
332	.exit		= dpd_exit,
333	.set_dfs_domain	= dpd_set_domain,
334	.add_pulse	= dpd_add_pulse,
335	.get_stats	= dpd_get_stats,
336	.region		= NL80211_DFS_UNSET,
337};
338
339struct dfs_pattern_detector *
340dfs_pattern_detector_init(struct ath_common *common,
341			  enum nl80211_dfs_regions region)
342{
343	struct dfs_pattern_detector *dpd;
344
345	if (!config_enabled(CONFIG_CFG80211_CERTIFICATION_ONUS))
346		return NULL;
347
348	dpd = kmalloc(sizeof(*dpd), GFP_KERNEL);
349	if (dpd == NULL)
350		return NULL;
351
352	*dpd = default_dpd;
353	INIT_LIST_HEAD(&dpd->channel_detectors);
354
355	dpd->common = common;
356	if (dpd->set_dfs_domain(dpd, region))
357		return dpd;
358
359	ath_dbg(common, DFS,"Could not set DFS domain to %d", region);
360	kfree(dpd);
361	return NULL;
362}
363EXPORT_SYMBOL(dfs_pattern_detector_init);
364