/* * 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 #include #include #include #include /* * 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 wf_chspec_malformed(chanspec_t 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; } /* * 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 lowre 20MHZ * sideband depending on the chanspec selected */ u8 wf_chspec_ctlchan(chanspec_t 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 */ ASSERT(CHSPEC_BW(chspec) == WL_CHANSPEC_BW_40); /* 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 { ASSERT(CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_LOWER); /* control chan is the lower 20 MHZ SB of the 40MHZ channel */ ctl_chan = LOWER_20_SB(CHSPEC_CHANNEL(chspec)); } } return ctl_chan; } /* * 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 wf_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; }