2 * Copyright (c) 2010 Broadcom Corporation
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.
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 ANY
11 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
13 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
14 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 #include <linux/ctype.h>
17 #include <linux/kernel.h>
23 * Verify the chanspec is using a legal set of parameters, i.e. that the
24 * chanspec specified a band, bw, ctl_sb and channel and that the
25 * combination could be legal given any set of circumstances.
26 * RETURNS: true is the chanspec is malformed, false if it looks good.
28 bool wf_chspec_malformed(chanspec_t chanspec)
30 /* must be 2G or 5G band */
31 if (!CHSPEC_IS5G(chanspec) && !CHSPEC_IS2G(chanspec))
33 /* must be 20 or 40 bandwidth */
34 if (!CHSPEC_IS40(chanspec) && !CHSPEC_IS20(chanspec))
37 /* 20MHZ b/w must have no ctl sb, 40 must have a ctl sb */
38 if (CHSPEC_IS20(chanspec)) {
39 if (!CHSPEC_SB_NONE(chanspec))
42 if (!CHSPEC_SB_UPPER(chanspec) && !CHSPEC_SB_LOWER(chanspec))
50 * This function returns the channel number that control traffic is being sent on, for legacy
51 * channels this is just the channel number, for 40MHZ channels it is the upper or lowre 20MHZ
52 * sideband depending on the chanspec selected
54 u8 wf_chspec_ctlchan(chanspec_t chspec)
58 /* Is there a sideband ? */
59 if (CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_NONE) {
60 return CHSPEC_CHANNEL(chspec);
62 /* we only support 40MHZ with sidebands */
63 ASSERT(CHSPEC_BW(chspec) == WL_CHANSPEC_BW_40);
64 /* chanspec channel holds the centre frequency, use that and the
65 * side band information to reconstruct the control channel number
67 if (CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_UPPER) {
68 /* control chan is the upper 20 MHZ SB of the 40MHZ channel */
69 ctl_chan = UPPER_20_SB(CHSPEC_CHANNEL(chspec));
71 ASSERT(CHSPEC_CTL_SB(chspec) ==
72 WL_CHANSPEC_CTL_SB_LOWER);
73 /* control chan is the lower 20 MHZ SB of the 40MHZ channel */
74 ctl_chan = LOWER_20_SB(CHSPEC_CHANNEL(chspec));
81 chanspec_t wf_chspec_ctlchspec(chanspec_t chspec)
83 chanspec_t ctl_chspec = 0;
86 ASSERT(!wf_chspec_malformed(chspec));
88 /* Is there a sideband ? */
89 if (CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_NONE) {
92 if (CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_UPPER) {
93 channel = UPPER_20_SB(CHSPEC_CHANNEL(chspec));
95 channel = LOWER_20_SB(CHSPEC_CHANNEL(chspec));
98 channel | WL_CHANSPEC_BW_20 | WL_CHANSPEC_CTL_SB_NONE;
99 ctl_chspec |= CHSPEC_BAND(chspec);
105 * Return the channel number for a given frequency and base frequency.
106 * The returned channel number is relative to the given base frequency.
107 * If the given base frequency is zero, a base frequency of 5 GHz is assumed for
108 * frequencies from 5 - 6 GHz, and 2.407 GHz is assumed for 2.4 - 2.5 GHz.
110 * Frequency is specified in MHz.
111 * The base frequency is specified as (start_factor * 500 kHz).
112 * Constants WF_CHAN_FACTOR_2_4_G, WF_CHAN_FACTOR_5_G are defined for
113 * 2.4 GHz and 5 GHz bands.
115 * The returned channel will be in the range [1, 14] in the 2.4 GHz band
116 * and [0, 200] otherwise.
117 * -1 is returned if the start_factor is WF_CHAN_FACTOR_2_4_G and the
118 * frequency is not a 2.4 GHz channel, or if the frequency is not and even
119 * multiple of 5 MHz from the base frequency to the base plus 1 GHz.
121 * Reference 802.11 REVma, section 17.3.8.3, and 802.11B section 18.4.6.2
123 int wf_mhz2channel(uint freq, uint start_factor)
129 /* take the default channel start frequency */
130 if (start_factor == 0) {
131 if (freq >= 2400 && freq <= 2500)
132 start_factor = WF_CHAN_FACTOR_2_4_G;
133 else if (freq >= 5000 && freq <= 6000)
134 start_factor = WF_CHAN_FACTOR_5_G;
137 if (freq == 2484 && start_factor == WF_CHAN_FACTOR_2_4_G)
140 base = start_factor / 2;
142 /* check that the frequency is in 1GHz range of the base */
143 if ((freq < base) || (freq > base + 1000))
146 offset = freq - base;
149 /* check that frequency is a 5MHz multiple from the base */
150 if (offset != (ch * 5))
153 /* restricted channel range check for 2.4G */
154 if (start_factor == WF_CHAN_FACTOR_2_4_G && (ch < 1 || ch > 13))
161 * Return the center frequency in MHz of the given channel and base frequency.
162 * The channel number is interpreted relative to the given base frequency.
164 * The valid channel range is [1, 14] in the 2.4 GHz band and [0, 200] otherwise.
165 * The base frequency is specified as (start_factor * 500 kHz).
166 * Constants WF_CHAN_FACTOR_2_4_G, WF_CHAN_FACTOR_4_G, and WF_CHAN_FACTOR_5_G
167 * are defined for 2.4 GHz, 4 GHz, and 5 GHz bands.
168 * The channel range of [1, 14] is only checked for a start_factor of
169 * WF_CHAN_FACTOR_2_4_G (4814 = 2407 * 2).
170 * Odd start_factors produce channels on .5 MHz boundaries, in which case
171 * the answer is rounded down to an integral MHz.
172 * -1 is returned for an out of range channel.
174 * Reference 802.11 REVma, section 17.3.8.3, and 802.11B section 18.4.6.2
176 int wf_channel2mhz(uint ch, uint start_factor)
180 if ((start_factor == WF_CHAN_FACTOR_2_4_G && (ch < 1 || ch > 14)) ||
183 else if ((start_factor == WF_CHAN_FACTOR_2_4_G) && (ch == 14))
186 freq = ch * 5 + start_factor / 2;