1/*
2 * Misc utility routines used by kernel or app-level.
3 * Contents are wifi-specific, used by any kernel or app-level
4 * software that might want wifi things as it grows.
5 *
6 * Copyright (C) 2010, Broadcom Corporation. All Rights Reserved.
7 *
8 * Permission to use, copy, modify, and/or distribute this software for any
9 * purpose with or without fee is hereby granted, provided that the above
10 * copyright notice and this permission notice appear in all copies.
11 *
12 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
13 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
14 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
15 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
16 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
17 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
18 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
19 * $Id: bcmwifi.c,v 1.31 2009/09/21 16:10:13 Exp $
20 */
21
22#include <typedefs.h>
23
24#ifdef BCMDRIVER
25#include <osl.h>
26#include <bcmutils.h>
27#define strtoul(nptr, endptr, base) bcm_strtoul((nptr), (endptr), (base))
28#define tolower(c) (bcm_isupper((c)) ? ((c) + 'a' - 'A') : (c))
29#else
30#include <stdio.h>
31#include <stdlib.h>
32#include <ctype.h>
33#ifndef ASSERT
34#define ASSERT(exp)
35#endif
36#endif /* BCMDRIVER */
37#include <bcmwifi.h>
38
39#if defined(WIN32) && (defined(BCMDLL) || defined(WLMDLL))
40#include <bcmstdlib.h> 	/* For wl/exe/GNUmakefile.brcm_wlu and GNUmakefile.wlm_dll */
41#endif
42
43/* Chanspec ASCII representation:
44 * <channel><band><bandwidth><ctl-sideband>
45 *   digit   [AB]     [N]        [UL]
46 *
47 * <channel>: channel number of the 10MHz or 20MHz channel,
48 *	or control sideband channel of 40MHz channel.
49 * <band>: A for 5GHz, B for 2.4GHz
50 * <bandwidth>: N for 10MHz, nothing for 20MHz or 40MHz
51 *	(ctl-sideband spec implies 40MHz)
52 * <ctl-sideband>: U for upper, L for lower
53 *
54 * <band> may be omitted on input, and will be assumed to be
55 * 2.4GHz if channel number <= 14.
56 *
57 * Examples:
58 *	8  ->  2.4GHz channel 8, 20MHz
59 *	8b ->  2.4GHz channel 8, 20MHz
60 *	8l ->  2.4GHz channel 8, 40MHz, lower ctl sideband
61 *	8a ->  5GHz channel 8 (low 5 GHz band), 20MHz
62 *	36 ->  5GHz channel 36, 20MHz
63 *	36l -> 5GHz channel 36, 40MHz, lower ctl sideband
64 *	40u -> 5GHz channel 40, 40MHz, upper ctl sideband
65 *	180n -> channel 180, 10MHz
66 */
67
68
69/* given a chanspec and a string buffer, format the chanspec as a
70 * string, and return the original pointer a.
71 * Min buffer length must be CHANSPEC_STR_LEN.
72 * On error return NULL
73 */
74char *
75wf_chspec_ntoa(chanspec_t chspec, char *buf)
76{
77	const char *band, *bw, *sb;
78	uint channel;
79
80	band = "";
81	bw = "";
82	sb = "";
83	channel = CHSPEC_CHANNEL(chspec);
84	/* check for non-default band spec */
85	if ((CHSPEC_IS2G(chspec) && channel > CH_MAX_2G_CHANNEL) ||
86	    (CHSPEC_IS5G(chspec) && channel <= CH_MAX_2G_CHANNEL))
87		band = (CHSPEC_IS2G(chspec)) ? "b" : "a";
88	if (CHSPEC_IS40(chspec)) {
89		if (CHSPEC_SB_UPPER(chspec)) {
90			sb = "u";
91			channel += CH_10MHZ_APART;
92		} else {
93			sb = "l";
94			channel -= CH_10MHZ_APART;
95		}
96	} else if (CHSPEC_IS10(chspec)) {
97		bw = "n";
98	}
99
100	/* Outputs a max of 6 chars including '\0'  */
101	snprintf(buf, 6, "%d%s%s%s", channel, band, bw, sb);
102	return (buf);
103}
104
105/* given a chanspec string, convert to a chanspec.
106 * On error return 0
107 */
108chanspec_t
109wf_chspec_aton(char *a)
110{
111	char *endp = NULL;
112	uint channel, band, bw, ctl_sb;
113	char c;
114
115	channel = strtoul(a, &endp, 10);
116
117	/* check for no digits parsed */
118	if (endp == a)
119		return 0;
120
121	if (channel > MAXCHANNEL)
122		return 0;
123
124	band = ((channel <= CH_MAX_2G_CHANNEL) ? WL_CHANSPEC_BAND_2G : WL_CHANSPEC_BAND_5G);
125	bw = WL_CHANSPEC_BW_20;
126	ctl_sb = WL_CHANSPEC_CTL_SB_NONE;
127
128	a = endp;
129
130	c = tolower(a[0]);
131	if (c == '\0')
132		goto done;
133
134	/* parse the optional ['A' | 'B'] band spec */
135	if (c == 'a' || c == 'b') {
136		band = (c == 'a') ? WL_CHANSPEC_BAND_5G : WL_CHANSPEC_BAND_2G;
137		a++;
138		c = tolower(a[0]);
139		if (c == '\0')
140			goto done;
141	}
142
143	/* parse bandwidth 'N' (10MHz) or 40MHz ctl sideband ['L' | 'U'] */
144	if (c == 'n') {
145		bw = WL_CHANSPEC_BW_10;
146	} else if (c == 'l') {
147		bw = WL_CHANSPEC_BW_40;
148		ctl_sb = WL_CHANSPEC_CTL_SB_LOWER;
149		/* adjust channel to center of 40MHz band */
150		if (channel <= (MAXCHANNEL - CH_20MHZ_APART))
151			channel += CH_10MHZ_APART;
152		else
153			return 0;
154	} else if (c == 'u') {
155		bw = WL_CHANSPEC_BW_40;
156		ctl_sb = WL_CHANSPEC_CTL_SB_UPPER;
157		/* adjust channel to center of 40MHz band */
158		if (channel > CH_20MHZ_APART)
159			channel -= CH_10MHZ_APART;
160		else
161			return 0;
162	} else {
163		return 0;
164	}
165
166done:
167	return (channel | band | bw | ctl_sb);
168}
169
170/*
171 * Verify the chanspec is using a legal set of parameters, i.e. that the
172 * chanspec specified a band, bw, ctl_sb and channel and that the
173 * combination could be legal given any set of circumstances.
174 * RETURNS: TRUE is the chanspec is malformed, false if it looks good.
175 */
176bool
177wf_chspec_malformed(chanspec_t chanspec)
178{
179	/* must be 2G or 5G band */
180	if (!CHSPEC_IS5G(chanspec) && !CHSPEC_IS2G(chanspec))
181		return TRUE;
182	/* must be 20 or 40 bandwidth */
183	if (!CHSPEC_IS40(chanspec) && !CHSPEC_IS20(chanspec))
184		return TRUE;
185
186	/* 20MHZ b/w must have no ctl sb, 40 must have a ctl sb */
187	if (CHSPEC_IS20(chanspec)) {
188		if (!CHSPEC_SB_NONE(chanspec))
189			return TRUE;
190	} else {
191		if (!CHSPEC_SB_UPPER(chanspec) && !CHSPEC_SB_LOWER(chanspec))
192		return TRUE;
193	}
194
195	return FALSE;
196}
197
198/*
199 * This function returns the channel number that control traffic is being sent on, for legacy
200 * channels this is just the channel number, for 40MHZ channels it is the upper or lowre 20MHZ
201 * sideband depending on the chanspec selected
202 */
203uint8
204wf_chspec_ctlchan(chanspec_t chspec)
205{
206	uint8 ctl_chan;
207
208	/* Is there a sideband ? */
209	if (CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_NONE) {
210		return CHSPEC_CHANNEL(chspec);
211	} else {
212		/* we only support 40MHZ with sidebands */
213		ASSERT(CHSPEC_BW(chspec) == WL_CHANSPEC_BW_40);
214		/* chanspec channel holds the centre frequency, use that and the
215		 * side band information to reconstruct the control channel number
216		 */
217		if (CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_UPPER) {
218			/* control chan is the upper 20 MHZ SB of the 40MHZ channel */
219			ctl_chan = UPPER_20_SB(CHSPEC_CHANNEL(chspec));
220		} else {
221			ASSERT(CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_LOWER);
222			/* control chan is the lower 20 MHZ SB of the 40MHZ channel */
223			ctl_chan = LOWER_20_SB(CHSPEC_CHANNEL(chspec));
224		}
225	}
226
227	return ctl_chan;
228}
229
230chanspec_t
231wf_chspec_ctlchspec(chanspec_t chspec)
232{
233	chanspec_t ctl_chspec = 0;
234	uint8 channel;
235
236	ASSERT(!wf_chspec_malformed(chspec));
237
238	/* Is there a sideband ? */
239	if (CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_NONE) {
240		return chspec;
241	} else {
242		if (CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_UPPER) {
243			channel = UPPER_20_SB(CHSPEC_CHANNEL(chspec));
244		} else {
245			channel = LOWER_20_SB(CHSPEC_CHANNEL(chspec));
246		}
247		ctl_chspec = channel | WL_CHANSPEC_BW_20 | WL_CHANSPEC_CTL_SB_NONE;
248		ctl_chspec |= CHSPEC_BAND(chspec);
249	}
250	return ctl_chspec;
251}
252
253/*
254 * Return the channel number for a given frequency and base frequency.
255 * The returned channel number is relative to the given base frequency.
256 * If the given base frequency is zero, a base frequency of 5 GHz is assumed for
257 * frequencies from 5 - 6 GHz, and 2.407 GHz is assumed for 2.4 - 2.5 GHz.
258 *
259 * Frequency is specified in MHz.
260 * The base frequency is specified as (start_factor * 500 kHz).
261 * Constants WF_CHAN_FACTOR_2_4_G, WF_CHAN_FACTOR_5_G are defined for
262 * 2.4 GHz and 5 GHz bands.
263 *
264 * The returned channel will be in the range [1, 14] in the 2.4 GHz band
265 * and [0, 200] otherwise.
266 * -1 is returned if the start_factor is WF_CHAN_FACTOR_2_4_G and the
267 * frequency is not a 2.4 GHz channel, or if the frequency is not and even
268 * multiple of 5 MHz from the base frequency to the base plus 1 GHz.
269 *
270 * Reference 802.11 REVma, section 17.3.8.3, and 802.11B section 18.4.6.2
271 */
272int
273wf_mhz2channel(uint freq, uint start_factor)
274{
275	int ch = -1;
276	uint base;
277	int offset;
278
279	/* take the default channel start frequency */
280	if (start_factor == 0) {
281		if (freq >= 2400 && freq <= 2500)
282			start_factor = WF_CHAN_FACTOR_2_4_G;
283		else if (freq >= 5000 && freq <= 6000)
284			start_factor = WF_CHAN_FACTOR_5_G;
285	}
286
287	if (freq == 2484 && start_factor == WF_CHAN_FACTOR_2_4_G)
288		return 14;
289
290	base = start_factor / 2;
291
292	/* check that the frequency is in 1GHz range of the base */
293	if ((freq < base) || (freq > base + 1000))
294		return -1;
295
296	offset = freq - base;
297	ch = offset / 5;
298
299	/* check that frequency is a 5MHz multiple from the base */
300	if (offset != (ch * 5))
301		return -1;
302
303	/* restricted channel range check for 2.4G */
304	if (start_factor == WF_CHAN_FACTOR_2_4_G && (ch < 1 || ch > 13))
305		return -1;
306
307	return ch;
308}
309
310/*
311 * Return the center frequency in MHz of the given channel and base frequency.
312 * The channel number is interpreted relative to the given base frequency.
313 *
314 * The valid channel range is [1, 14] in the 2.4 GHz band and [0, 200] otherwise.
315 * The base frequency is specified as (start_factor * 500 kHz).
316 * Constants WF_CHAN_FACTOR_2_4_G, WF_CHAN_FACTOR_4_G, and WF_CHAN_FACTOR_5_G
317 * are defined for 2.4 GHz, 4 GHz, and 5 GHz bands.
318 * The channel range of [1, 14] is only checked for a start_factor of
319 * WF_CHAN_FACTOR_2_4_G (4814 = 2407 * 2).
320 * Odd start_factors produce channels on .5 MHz boundaries, in which case
321 * the answer is rounded down to an integral MHz.
322 * -1 is returned for an out of range channel.
323 *
324 * Reference 802.11 REVma, section 17.3.8.3, and 802.11B section 18.4.6.2
325 */
326int
327wf_channel2mhz(uint ch, uint start_factor)
328{
329	int freq;
330
331	if ((start_factor == WF_CHAN_FACTOR_2_4_G && (ch < 1 || ch > 14)) ||
332	    (ch > 200))
333		freq = -1;
334	else if ((start_factor == WF_CHAN_FACTOR_2_4_G) && (ch == 14))
335		freq = 2484;
336	else
337		freq = ch * 5 + start_factor / 2;
338
339	return freq;
340}
341