package/kernel/mac80211/patches/347-0002-cfg80211-support-ieee80211-freq-limit-DT-property.patch

   1 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
   2 Date: Wed, 4 Jan 2017 18:58:31 +0100
   3 Subject: [PATCH] cfg80211: support ieee80211-freq-limit DT property
   4 MIME-Version: 1.0
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   7
   8 This patch adds a helper for reading that new property and applying
   9 limitations of supported channels specified this way.
  10 It is used with devices that normally support a wide wireless band but
  11 in a given config are limited to some part of it (usually due to board
  12 design). For example a dual-band chipset may be able to support one band
  13 only because of used antennas.
  14 It's also common that tri-band routers have separated radios for lower
  15 and higher part of 5 GHz band and it may be impossible to say which is
  16 which without a DT info.
  17
  18 Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
  19 [add new function to documentation, fix link]
  20 Signed-off-by: Johannes Berg <johannes.berg@intel.com>
  21 ---
  22  create mode 100644 net/wireless/of.c
  23
  24 --- a/include/net/cfg80211.h
  25 +++ b/include/net/cfg80211.h
  26 @@ -311,6 +311,34 @@ struct ieee80211_supported_band {
  27         struct ieee80211_sta_vht_cap vht_cap;
  28  };
  29
  30 +/**
  31 + * wiphy_read_of_freq_limits - read frequency limits from device tree
  32 + *
  33 + * @wiphy: the wireless device to get extra limits for
  34 + *
  35 + * Some devices may have extra limitations specified in DT. This may be useful
  36 + * for chipsets that normally support more bands but are limited due to board
  37 + * design (e.g. by antennas or external power amplifier).
  38 + *
  39 + * This function reads info from DT and uses it to *modify* channels (disable
  40 + * unavailable ones). It's usually a *bad* idea to use it in drivers with
  41 + * shared channel data as DT limitations are device specific. You should make
  42 + * sure to call it only if channels in wiphy are copied and can be modified
  43 + * without affecting other devices.
  44 + *
  45 + * As this function access device node it has to be called after set_wiphy_dev.
  46 + * It also modifies channels so they have to be set first.
  47 + * If using this helper, call it before wiphy_register().
  48 + */
  49 +#ifdef CONFIG_OF
  50 +void wiphy_read_of_freq_limits(struct wiphy *wiphy);
  51 +#else /* CONFIG_OF */
  52 +static inline void wiphy_read_of_freq_limits(struct wiphy *wiphy)
  53 +{
  54 +}
  55 +#endif /* !CONFIG_OF */
  56 +
  57 +
  58  /*
  59   * Wireless hardware/device configuration structures and methods
  60   */
  61 --- a/net/wireless/Makefile
  62 +++ b/net/wireless/Makefile
  63 @@ -11,6 +11,7 @@ obj-$(CONFIG_WEXT_PRIV) += wext-priv.o
  64
  65  cfg80211-y += core.o sysfs.o radiotap.o util.o reg.o scan.o nl80211.o
  66  cfg80211-y += mlme.o ibss.o sme.o chan.o ethtool.o mesh.o ap.o trace.o ocb.o
  67 +cfg80211-$(CONFIG_OF) += of.o
  68  cfg80211-$(CPTCFG_CFG80211_DEBUGFS) += debugfs.o
  69  cfg80211-$(CPTCFG_CFG80211_WEXT) += wext-compat.o wext-sme.o
  70  cfg80211-$(CPTCFG_CFG80211_INTERNAL_REGDB) += regdb.o
  71 --- /dev/null
  72 +++ b/net/wireless/of.c
  73 @@ -0,0 +1,138 @@
  74 +/*
  75 + * Copyright (C) 2017 Rafał Miłecki <rafal@milecki.pl>
  76 + *
  77 + * Permission to use, copy, modify, and/or distribute this software for any
  78 + * purpose with or without fee is hereby granted, provided that the above
  79 + * copyright notice and this permission notice appear in all copies.
  80 + *
  81 + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  82 + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  83 + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  84 + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  85 + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  86 + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  87 + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  88 + */
  89 +
  90 +#include <linux/of.h>
  91 +#include <net/cfg80211.h>
  92 +#include "core.h"
  93 +
  94 +static bool wiphy_freq_limits_valid_chan(struct wiphy *wiphy,
  95 +                                        struct ieee80211_freq_range *freq_limits,
  96 +                                        unsigned int n_freq_limits,
  97 +                                        struct ieee80211_channel *chan)
  98 +{
  99 +       u32 bw = MHZ_TO_KHZ(20);
 100 +       int i;
 101 +
 102 +       for (i = 0; i < n_freq_limits; i++) {
 103 +               struct ieee80211_freq_range *limit = &freq_limits[i];
 104 +
 105 +               if (cfg80211_does_bw_fit_range(limit,
 106 +                                              MHZ_TO_KHZ(chan->center_freq),
 107 +                                              bw))
 108 +                       return true;
 109 +       }
 110 +
 111 +       return false;
 112 +}
 113 +
 114 +static void wiphy_freq_limits_apply(struct wiphy *wiphy,
 115 +                                   struct ieee80211_freq_range *freq_limits,
 116 +                                   unsigned int n_freq_limits)
 117 +{
 118 +       enum nl80211_band band;
 119 +       int i;
 120 +
 121 +       if (WARN_ON(!n_freq_limits))
 122 +               return;
 123 +
 124 +       for (band = 0; band < NUM_NL80211_BANDS; band++) {
 125 +               struct ieee80211_supported_band *sband = wiphy->bands[band];
 126 +
 127 +               if (!sband)
 128 +                       continue;
 129 +
 130 +               for (i = 0; i < sband->n_channels; i++) {
 131 +                       struct ieee80211_channel *chan = &sband->channels[i];
 132 +
 133 +                       if (chan->flags & IEEE80211_CHAN_DISABLED)
 134 +                               continue;
 135 +
 136 +                       if (!wiphy_freq_limits_valid_chan(wiphy, freq_limits,
 137 +                                                         n_freq_limits,
 138 +                                                         chan)) {
 139 +                               pr_debug("Disabling freq %d MHz as it's out of OF limits\n",
 140 +                                        chan->center_freq);
 141 +                               chan->flags |= IEEE80211_CHAN_DISABLED;
 142 +                       }
 143 +               }
 144 +       }
 145 +}
 146 +
 147 +void wiphy_read_of_freq_limits(struct wiphy *wiphy)
 148 +{
 149 +       struct device *dev = wiphy_dev(wiphy);
 150 +       struct device_node *np;
 151 +       struct property *prop;
 152 +       struct ieee80211_freq_range *freq_limits;
 153 +       unsigned int n_freq_limits;
 154 +       const __be32 *p;
 155 +       int len, i;
 156 +       int err = 0;
 157 +
 158 +       if (!dev)
 159 +               return;
 160 +       np = dev_of_node(dev);
 161 +       if (!np)
 162 +               return;
 163 +
 164 +       prop = of_find_property(np, "ieee80211-freq-limit", &len);
 165 +       if (!prop)
 166 +               return;
 167 +
 168 +       if (!len || len % sizeof(u32) || len / sizeof(u32) % 2) {
 169 +               dev_err(dev, "ieee80211-freq-limit wrong format");
 170 +               return;
 171 +       }
 172 +       n_freq_limits = len / sizeof(u32) / 2;
 173 +
 174 +       freq_limits = kcalloc(n_freq_limits, sizeof(*freq_limits), GFP_KERNEL);
 175 +       if (!freq_limits) {
 176 +               err = -ENOMEM;
 177 +               goto out_kfree;
 178 +       }
 179 +
 180 +       p = NULL;
 181 +       for (i = 0; i < n_freq_limits; i++) {
 182 +               struct ieee80211_freq_range *limit = &freq_limits[i];
 183 +
 184 +               p = of_prop_next_u32(prop, p, &limit->start_freq_khz);
 185 +               if (!p) {
 186 +                       err = -EINVAL;
 187 +                       goto out_kfree;
 188 +               }
 189 +
 190 +               p = of_prop_next_u32(prop, p, &limit->end_freq_khz);
 191 +               if (!p) {
 192 +                       err = -EINVAL;
 193 +                       goto out_kfree;
 194 +               }
 195 +
 196 +               if (!limit->start_freq_khz ||
 197 +                   !limit->end_freq_khz ||
 198 +                   limit->start_freq_khz >= limit->end_freq_khz) {
 199 +                       err = -EINVAL;
 200 +                       goto out_kfree;
 201 +               }
 202 +       }
 203 +
 204 +       wiphy_freq_limits_apply(wiphy, freq_limits, n_freq_limits);
 205 +
 206 +out_kfree:
 207 +       kfree(freq_limits);
 208 +       if (err)
 209 +               dev_err(dev, "Failed to get limits: %d\n", err);
 210 +}
 211 +EXPORT_SYMBOL(wiphy_read_of_freq_limits);