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/*
* Copyright (c) 2010 Broadcom Corporation
*
* 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 <brcmu_wifi.h>
/*
* Verify the chanspec is using a legal set of parameters, i.e. that the
* chanspec specified a band, bw, ctl_sb and channel and that the
* combination could be legal given any set of circumstances.
* RETURNS: true is the chanspec is malformed, false if it looks good.
*/
bool brcmu_chspec_malformed(u16 chanspec)
{
/* must be 2G or 5G band */
if (!CHSPEC_IS5G(chanspec) && !CHSPEC_IS2G(chanspec))
return true;
/* must be 20 or 40 bandwidth */
if (!CHSPEC_IS40(chanspec) && !CHSPEC_IS20(chanspec))
return true;
/* 20MHZ b/w must have no ctl sb, 40 must have a ctl sb */
if (CHSPEC_IS20(chanspec)) {
if (!CHSPEC_SB_NONE(chanspec))
return true;
} else if (!CHSPEC_SB_UPPER(chanspec) && !CHSPEC_SB_LOWER(chanspec)) {
return true;
}
return false;
}
EXPORT_SYMBOL(brcmu_chspec_malformed);
/*
* This function returns the channel number that control traffic is being sent
* on, for legacy channels this is just the channel number, for 40MHZ channels
* it is the upper or lower 20MHZ sideband depending on the chanspec selected.
*/
u8 brcmu_chspec_ctlchan(u16 chspec)
{
u8 ctl_chan;
/* Is there a sideband ? */
if (CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_NONE) {
return CHSPEC_CHANNEL(chspec);
} else {
/*
* we only support 40MHZ with sidebands. chanspec channel holds
* the centre frequency, use that and the side band information
* to reconstruct the control channel number
*/
if (CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_UPPER)
/*
* control chan is the upper 20 MHZ SB of the
* 40MHZ channel
*/
ctl_chan = upper_20_sb(CHSPEC_CHANNEL(chspec));
else
/*
* control chan is the lower 20 MHZ SB of the
* 40MHZ channel
*/
ctl_chan = lower_20_sb(CHSPEC_CHANNEL(chspec));
}
return ctl_chan;
}
EXPORT_SYMBOL(brcmu_chspec_ctlchan);
/*
* Return the channel number for a given frequency and base frequency.
* The returned channel number is relative to the given base frequency.
* If the given base frequency is zero, a base frequency of 5 GHz is assumed for
* frequencies from 5 - 6 GHz, and 2.407 GHz is assumed for 2.4 - 2.5 GHz.
*
* Frequency is specified in MHz.
* The base frequency is specified as (start_factor * 500 kHz).
* Constants WF_CHAN_FACTOR_2_4_G, WF_CHAN_FACTOR_5_G are defined for
* 2.4 GHz and 5 GHz bands.
*
* The returned channel will be in the range [1, 14] in the 2.4 GHz band
* and [0, 200] otherwise.
* -1 is returned if the start_factor is WF_CHAN_FACTOR_2_4_G and the
* frequency is not a 2.4 GHz channel, or if the frequency is not and even
* multiple of 5 MHz from the base frequency to the base plus 1 GHz.
*
* Reference 802.11 REVma, section 17.3.8.3, and 802.11B section 18.4.6.2
*/
int brcmu_mhz2channel(uint freq, uint start_factor)
{
int ch = -1;
uint base;
int offset;
/* take the default channel start frequency */
if (start_factor == 0) {
if (freq >= 2400 && freq <= 2500)
start_factor = WF_CHAN_FACTOR_2_4_G;
else if (freq >= 5000 && freq <= 6000)
start_factor = WF_CHAN_FACTOR_5_G;
}
if (freq == 2484 && start_factor == WF_CHAN_FACTOR_2_4_G)
return 14;
base = start_factor / 2;
/* check that the frequency is in 1GHz range of the base */
if ((freq < base) || (freq > base + 1000))
return -1;
offset = freq - base;
ch = offset / 5;
/* check that frequency is a 5MHz multiple from the base */
if (offset != (ch * 5))
return -1;
/* restricted channel range check for 2.4G */
if (start_factor == WF_CHAN_FACTOR_2_4_G && (ch < 1 || ch > 13))
return -1;
return ch;
}
EXPORT_SYMBOL(brcmu_mhz2channel);
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