net/wireless/of.c

   1 /*
   2  * Copyright (C) 2017 Rafał Miłecki <rafal@milecki.pl>
   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
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 #include <linux/of.h>
  18 #include <net/cfg80211.h>
  19 #include "core.h"
  20
  21 static bool wiphy_freq_limits_valid_chan(struct wiphy *wiphy,
  22                                          struct ieee80211_freq_range *freq_limits,
  23                                          unsigned int n_freq_limits,
  24                                          struct ieee80211_channel *chan)
  25 {
  26         u32 bw = MHZ_TO_KHZ(20);
  27         int i;
  28
  29         for (i = 0; i < n_freq_limits; i++) {
  30                 struct ieee80211_freq_range *limit = &freq_limits[i];
  31
  32                 if (cfg80211_does_bw_fit_range(limit,
  33                                                MHZ_TO_KHZ(chan->center_freq),
  34                                                bw))
  35                         return true;
  36         }
  37
  38         return false;
  39 }
  40
  41 static void wiphy_freq_limits_apply(struct wiphy *wiphy,
  42                                     struct ieee80211_freq_range *freq_limits,
  43                                     unsigned int n_freq_limits)
  44 {
  45         enum nl80211_band band;
  46         int i;
  47
  48         if (WARN_ON(!n_freq_limits))
  49                 return;
  50
  51         for (band = 0; band < NUM_NL80211_BANDS; band++) {
  52                 struct ieee80211_supported_band *sband = wiphy->bands[band];
  53
  54                 if (!sband)
  55                         continue;
  56
  57                 for (i = 0; i < sband->n_channels; i++) {
  58                         struct ieee80211_channel *chan = &sband->channels[i];
  59
  60                         if (chan->flags & IEEE80211_CHAN_DISABLED)
  61                                 continue;
  62
  63                         if (!wiphy_freq_limits_valid_chan(wiphy, freq_limits,
  64                                                           n_freq_limits,
  65                                                           chan)) {
  66                                 pr_debug("Disabling freq %d MHz as it's out of OF limits\n",
  67                                          chan->center_freq);
  68                                 chan->flags |= IEEE80211_CHAN_DISABLED;
  69                         }
  70                 }
  71         }
  72 }
  73
  74 void wiphy_read_of_freq_limits(struct wiphy *wiphy)
  75 {
  76         struct device *dev = wiphy_dev(wiphy);
  77         struct device_node *np;
  78         struct property *prop;
  79         struct ieee80211_freq_range *freq_limits;
  80         unsigned int n_freq_limits;
  81         const __be32 *p;
  82         int len, i;
  83         int err = 0;
  84
  85         if (!dev)
  86                 return;
  87         np = dev_of_node(dev);
  88         if (!np)
  89                 return;
  90
  91         prop = of_find_property(np, "ieee80211-freq-limit", &len);
  92         if (!prop)
  93                 return;
  94
  95         if (!len || len % sizeof(u32) || len / sizeof(u32) % 2) {
  96                 dev_err(dev, "ieee80211-freq-limit wrong format");
  97                 return;
  98         }
  99         n_freq_limits = len / sizeof(u32) / 2;
 100
 101         freq_limits = kcalloc(n_freq_limits, sizeof(*freq_limits), GFP_KERNEL);
 102         if (!freq_limits) {
 103                 err = -ENOMEM;
 104                 goto out_kfree;
 105         }
 106
 107         p = NULL;
 108         for (i = 0; i < n_freq_limits; i++) {
 109                 struct ieee80211_freq_range *limit = &freq_limits[i];
 110
 111                 p = of_prop_next_u32(prop, p, &limit->start_freq_khz);
 112                 if (!p) {
 113                         err = -EINVAL;
 114                         goto out_kfree;
 115                 }
 116
 117                 p = of_prop_next_u32(prop, p, &limit->end_freq_khz);
 118                 if (!p) {
 119                         err = -EINVAL;
 120                         goto out_kfree;
 121                 }
 122
 123                 if (!limit->start_freq_khz ||
 124                     !limit->end_freq_khz ||
 125                     limit->start_freq_khz >= limit->end_freq_khz) {
 126                         err = -EINVAL;
 127                         goto out_kfree;
 128                 }
 129         }
 130
 131         wiphy_freq_limits_apply(wiphy, freq_limits, n_freq_limits);
 132
 133 out_kfree:
 134         kfree(freq_limits);
 135         if (err)
 136                 dev_err(dev, "Failed to get limits: %d\n", err);
 137 }
 138 EXPORT_SYMBOL(wiphy_read_of_freq_limits);