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>
19 #include <linux/netdevice.h>
27 * Verify the chanspec is using a legal set of parameters, i.e. that the
28 * chanspec specified a band, bw, ctl_sb and channel and that the
29 * combination could be legal given any set of circumstances.
30 * RETURNS: true is the chanspec is malformed, false if it looks good.
32 bool wf_chspec_malformed(chanspec_t chanspec)
34 /* must be 2G or 5G band */
35 if (!CHSPEC_IS5G(chanspec) && !CHSPEC_IS2G(chanspec))
37 /* must be 20 or 40 bandwidth */
38 if (!CHSPEC_IS40(chanspec) && !CHSPEC_IS20(chanspec))
41 /* 20MHZ b/w must have no ctl sb, 40 must have a ctl sb */
42 if (CHSPEC_IS20(chanspec)) {
43 if (!CHSPEC_SB_NONE(chanspec))
46 if (!CHSPEC_SB_UPPER(chanspec) && !CHSPEC_SB_LOWER(chanspec))
54 * This function returns the channel number that control traffic is being sent on, for legacy
55 * channels this is just the channel number, for 40MHZ channels it is the upper or lowre 20MHZ
56 * sideband depending on the chanspec selected
58 u8 wf_chspec_ctlchan(chanspec_t chspec)
62 /* Is there a sideband ? */
63 if (CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_NONE) {
64 return CHSPEC_CHANNEL(chspec);
66 /* we only support 40MHZ with sidebands */
67 ASSERT(CHSPEC_BW(chspec) == WL_CHANSPEC_BW_40);
68 /* chanspec channel holds the centre frequency, use that and the
69 * side band information to reconstruct the control channel number
71 if (CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_UPPER) {
72 /* control chan is the upper 20 MHZ SB of the 40MHZ channel */
73 ctl_chan = UPPER_20_SB(CHSPEC_CHANNEL(chspec));
75 ASSERT(CHSPEC_CTL_SB(chspec) ==
76 WL_CHANSPEC_CTL_SB_LOWER);
77 /* control chan is the lower 20 MHZ SB of the 40MHZ channel */
78 ctl_chan = LOWER_20_SB(CHSPEC_CHANNEL(chspec));
85 chanspec_t wf_chspec_ctlchspec(chanspec_t chspec)
87 chanspec_t ctl_chspec = 0;
90 ASSERT(!wf_chspec_malformed(chspec));
92 /* Is there a sideband ? */
93 if (CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_NONE) {
96 if (CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_UPPER) {
97 channel = UPPER_20_SB(CHSPEC_CHANNEL(chspec));
99 channel = LOWER_20_SB(CHSPEC_CHANNEL(chspec));
102 channel | WL_CHANSPEC_BW_20 | WL_CHANSPEC_CTL_SB_NONE;
103 ctl_chspec |= CHSPEC_BAND(chspec);
109 * Return the channel number for a given frequency and base frequency.
110 * The returned channel number is relative to the given base frequency.
111 * If the given base frequency is zero, a base frequency of 5 GHz is assumed for
112 * frequencies from 5 - 6 GHz, and 2.407 GHz is assumed for 2.4 - 2.5 GHz.
114 * Frequency is specified in MHz.
115 * The base frequency is specified as (start_factor * 500 kHz).
116 * Constants WF_CHAN_FACTOR_2_4_G, WF_CHAN_FACTOR_5_G are defined for
117 * 2.4 GHz and 5 GHz bands.
119 * The returned channel will be in the range [1, 14] in the 2.4 GHz band
120 * and [0, 200] otherwise.
121 * -1 is returned if the start_factor is WF_CHAN_FACTOR_2_4_G and the
122 * frequency is not a 2.4 GHz channel, or if the frequency is not and even
123 * multiple of 5 MHz from the base frequency to the base plus 1 GHz.
125 * Reference 802.11 REVma, section 17.3.8.3, and 802.11B section 18.4.6.2
127 int wf_mhz2channel(uint freq, uint start_factor)
133 /* take the default channel start frequency */
134 if (start_factor == 0) {
135 if (freq >= 2400 && freq <= 2500)
136 start_factor = WF_CHAN_FACTOR_2_4_G;
137 else if (freq >= 5000 && freq <= 6000)
138 start_factor = WF_CHAN_FACTOR_5_G;
141 if (freq == 2484 && start_factor == WF_CHAN_FACTOR_2_4_G)
144 base = start_factor / 2;
146 /* check that the frequency is in 1GHz range of the base */
147 if ((freq < base) || (freq > base + 1000))
150 offset = freq - base;
153 /* check that frequency is a 5MHz multiple from the base */
154 if (offset != (ch * 5))
157 /* restricted channel range check for 2.4G */
158 if (start_factor == WF_CHAN_FACTOR_2_4_G && (ch < 1 || ch > 13))
165 * Return the center frequency in MHz of the given channel and base frequency.
166 * The channel number is interpreted relative to the given base frequency.
168 * The valid channel range is [1, 14] in the 2.4 GHz band and [0, 200] otherwise.
169 * The base frequency is specified as (start_factor * 500 kHz).
170 * Constants WF_CHAN_FACTOR_2_4_G, WF_CHAN_FACTOR_4_G, and WF_CHAN_FACTOR_5_G
171 * are defined for 2.4 GHz, 4 GHz, and 5 GHz bands.
172 * The channel range of [1, 14] is only checked for a start_factor of
173 * WF_CHAN_FACTOR_2_4_G (4814 = 2407 * 2).
174 * Odd start_factors produce channels on .5 MHz boundaries, in which case
175 * the answer is rounded down to an integral MHz.
176 * -1 is returned for an out of range channel.
178 * Reference 802.11 REVma, section 17.3.8.3, and 802.11B section 18.4.6.2
180 int wf_channel2mhz(uint ch, uint start_factor)
184 if ((start_factor == WF_CHAN_FACTOR_2_4_G && (ch < 1 || ch > 14)) ||
187 else if ((start_factor == WF_CHAN_FACTOR_2_4_G) && (ch == 14))
190 freq = ch * 5 + start_factor / 2;