drivers/staging/brcm80211/util/bcmwifi.c

   1 /*
   2  * Copyright (c) 2010 Broadcom Corporation
   3  *
   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.
   7  *
   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.
  15  */
  16 #include <linux/ctype.h>
  17 #include <linux/kernel.h>
  18 #include <osl.h>
  19 #include <bcmdefs.h>
  20 #include <bcmutils.h>
  21 #include <bcmwifi.h>
  22
  23 /*
  24  * Verify the chanspec is using a legal set of parameters, i.e. that the
  25  * chanspec specified a band, bw, ctl_sb and channel and that the
  26  * combination could be legal given any set of circumstances.
  27  * RETURNS: true is the chanspec is malformed, false if it looks good.
  28  */
  29 bool wf_chspec_malformed(chanspec_t chanspec)
  30 {
  31         /* must be 2G or 5G band */
  32         if (!CHSPEC_IS5G(chanspec) && !CHSPEC_IS2G(chanspec))
  33                 return true;
  34         /* must be 20 or 40 bandwidth */
  35         if (!CHSPEC_IS40(chanspec) && !CHSPEC_IS20(chanspec))
  36                 return true;
  37
  38         /* 20MHZ b/w must have no ctl sb, 40 must have a ctl sb */
  39         if (CHSPEC_IS20(chanspec)) {
  40                 if (!CHSPEC_SB_NONE(chanspec))
  41                         return true;
  42         } else {
  43                 if (!CHSPEC_SB_UPPER(chanspec) && !CHSPEC_SB_LOWER(chanspec))
  44                         return true;
  45         }
  46
  47         return false;
  48 }
  49
  50 /*
  51  * This function returns the channel number that control traffic is being sent on, for legacy
  52  * channels this is just the channel number, for 40MHZ channels it is the upper or lowre 20MHZ
  53  * sideband depending on the chanspec selected
  54  */
  55 u8 wf_chspec_ctlchan(chanspec_t chspec)
  56 {
  57         u8 ctl_chan;
  58
  59         /* Is there a sideband ? */
  60         if (CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_NONE) {
  61                 return CHSPEC_CHANNEL(chspec);
  62         } else {
  63                 /* we only support 40MHZ with sidebands */
  64                 ASSERT(CHSPEC_BW(chspec) == WL_CHANSPEC_BW_40);
  65                 /* chanspec channel holds the centre frequency, use that and the
  66                  * side band information to reconstruct the control channel number
  67                  */
  68                 if (CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_UPPER) {
  69                         /* control chan is the upper 20 MHZ SB of the 40MHZ channel */
  70                         ctl_chan = UPPER_20_SB(CHSPEC_CHANNEL(chspec));
  71                 } else {
  72                         ASSERT(CHSPEC_CTL_SB(chspec) ==
  73                                WL_CHANSPEC_CTL_SB_LOWER);
  74                         /* control chan is the lower 20 MHZ SB of the 40MHZ channel */
  75                         ctl_chan = LOWER_20_SB(CHSPEC_CHANNEL(chspec));
  76                 }
  77         }
  78
  79         return ctl_chan;
  80 }
  81
  82 chanspec_t wf_chspec_ctlchspec(chanspec_t chspec)
  83 {
  84         chanspec_t ctl_chspec = 0;
  85         u8 channel;
  86
  87         ASSERT(!wf_chspec_malformed(chspec));
  88
  89         /* Is there a sideband ? */
  90         if (CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_NONE) {
  91                 return chspec;
  92         } else {
  93                 if (CHSPEC_CTL_SB(chspec) == WL_CHANSPEC_CTL_SB_UPPER) {
  94                         channel = UPPER_20_SB(CHSPEC_CHANNEL(chspec));
  95                 } else {
  96                         channel = LOWER_20_SB(CHSPEC_CHANNEL(chspec));
  97                 }
  98                 ctl_chspec =
  99                     channel | WL_CHANSPEC_BW_20 | WL_CHANSPEC_CTL_SB_NONE;
 100                 ctl_chspec |= CHSPEC_BAND(chspec);
 101         }
 102         return ctl_chspec;
 103 }
 104
 105 /*
 106  * Return the channel number for a given frequency and base frequency.
 107  * The returned channel number is relative to the given base frequency.
 108  * If the given base frequency is zero, a base frequency of 5 GHz is assumed for
 109  * frequencies from 5 - 6 GHz, and 2.407 GHz is assumed for 2.4 - 2.5 GHz.
 110  *
 111  * Frequency is specified in MHz.
 112  * The base frequency is specified as (start_factor * 500 kHz).
 113  * Constants WF_CHAN_FACTOR_2_4_G, WF_CHAN_FACTOR_5_G are defined for
 114  * 2.4 GHz and 5 GHz bands.
 115  *
 116  * The returned channel will be in the range [1, 14] in the 2.4 GHz band
 117  * and [0, 200] otherwise.
 118  * -1 is returned if the start_factor is WF_CHAN_FACTOR_2_4_G and the
 119  * frequency is not a 2.4 GHz channel, or if the frequency is not and even
 120  * multiple of 5 MHz from the base frequency to the base plus 1 GHz.
 121  *
 122  * Reference 802.11 REVma, section 17.3.8.3, and 802.11B section 18.4.6.2
 123  */
 124 int wf_mhz2channel(uint freq, uint start_factor)
 125 {
 126         int ch = -1;
 127         uint base;
 128         int offset;
 129
 130         /* take the default channel start frequency */
 131         if (start_factor == 0) {
 132                 if (freq >= 2400 && freq <= 2500)
 133                         start_factor = WF_CHAN_FACTOR_2_4_G;
 134                 else if (freq >= 5000 && freq <= 6000)
 135                         start_factor = WF_CHAN_FACTOR_5_G;
 136         }
 137
 138         if (freq == 2484 && start_factor == WF_CHAN_FACTOR_2_4_G)
 139                 return 14;
 140
 141         base = start_factor / 2;
 142
 143         /* check that the frequency is in 1GHz range of the base */
 144         if ((freq < base) || (freq > base + 1000))
 145                 return -1;
 146
 147         offset = freq - base;
 148         ch = offset / 5;
 149
 150         /* check that frequency is a 5MHz multiple from the base */
 151         if (offset != (ch * 5))
 152                 return -1;
 153
 154         /* restricted channel range check for 2.4G */
 155         if (start_factor == WF_CHAN_FACTOR_2_4_G && (ch < 1 || ch > 13))
 156                 return -1;
 157
 158         return ch;
 159 }
 160