cfg80211: support ieee80211-freq-limit DT property
This patch adds a helper for reading that new property and applying limitations of supported channels specified this way. It is used with devices that normally support a wide wireless band but in a given config are limited to some part of it (usually due to board design). For example a dual-band chipset may be able to support one band only because of used antennas. It's also common that tri-band routers have separated radios for lower and higher part of 5 GHz band and it may be impossible to say which is which without a DT info. Signed-off-by: Rafał Miłecki <rafal@milecki.pl> [add new function to documentation, fix link] Signed-off-by: Johannes Berg <johannes.berg@intel.com>zero-colors
Rafał Miłecki
Johannes Berg
parent
4787cfa084
commit
e691ac2f75
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@ -44,6 +44,9 @@ Device registration
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.. kernel-doc:: include/net/cfg80211.h
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:functions: wiphy_new
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.. kernel-doc:: include/net/cfg80211.h
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:functions: wiphy_read_of_freq_limits
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.. kernel-doc:: include/net/cfg80211.h
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:functions: wiphy_register
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@ -311,6 +311,34 @@ struct ieee80211_supported_band {
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struct ieee80211_sta_vht_cap vht_cap;
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};
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/**
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* wiphy_read_of_freq_limits - read frequency limits from device tree
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*
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* @wiphy: the wireless device to get extra limits for
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*
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* Some devices may have extra limitations specified in DT. This may be useful
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* for chipsets that normally support more bands but are limited due to board
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* design (e.g. by antennas or external power amplifier).
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*
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* This function reads info from DT and uses it to *modify* channels (disable
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* unavailable ones). It's usually a *bad* idea to use it in drivers with
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* shared channel data as DT limitations are device specific. You should make
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* sure to call it only if channels in wiphy are copied and can be modified
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* without affecting other devices.
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*
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* As this function access device node it has to be called after set_wiphy_dev.
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* It also modifies channels so they have to be set first.
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* If using this helper, call it before wiphy_register().
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*/
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#ifdef CONFIG_OF
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void wiphy_read_of_freq_limits(struct wiphy *wiphy);
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#else /* CONFIG_OF */
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static inline void wiphy_read_of_freq_limits(struct wiphy *wiphy)
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{
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}
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#endif /* !CONFIG_OF */
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/*
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* Wireless hardware/device configuration structures and methods
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*/
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@ -11,6 +11,7 @@ obj-$(CONFIG_WEXT_PRIV) += wext-priv.o
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cfg80211-y += core.o sysfs.o radiotap.o util.o reg.o scan.o nl80211.o
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cfg80211-y += mlme.o ibss.o sme.o chan.o ethtool.o mesh.o ap.o trace.o ocb.o
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cfg80211-$(CONFIG_OF) += of.o
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cfg80211-$(CONFIG_CFG80211_DEBUGFS) += debugfs.o
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cfg80211-$(CONFIG_CFG80211_WEXT) += wext-compat.o wext-sme.o
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cfg80211-$(CONFIG_CFG80211_INTERNAL_REGDB) += regdb.o
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@ -0,0 +1,138 @@
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/*
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* Copyright (C) 2017 Rafał Miłecki <rafal@milecki.pl>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <linux/of.h>
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#include <net/cfg80211.h>
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#include "core.h"
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static bool wiphy_freq_limits_valid_chan(struct wiphy *wiphy,
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struct ieee80211_freq_range *freq_limits,
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unsigned int n_freq_limits,
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struct ieee80211_channel *chan)
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{
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u32 bw = MHZ_TO_KHZ(20);
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int i;
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for (i = 0; i < n_freq_limits; i++) {
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struct ieee80211_freq_range *limit = &freq_limits[i];
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if (cfg80211_does_bw_fit_range(limit,
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MHZ_TO_KHZ(chan->center_freq),
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bw))
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return true;
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}
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return false;
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}
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static void wiphy_freq_limits_apply(struct wiphy *wiphy,
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struct ieee80211_freq_range *freq_limits,
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unsigned int n_freq_limits)
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{
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enum nl80211_band band;
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int i;
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if (WARN_ON(!n_freq_limits))
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return;
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for (band = 0; band < NUM_NL80211_BANDS; band++) {
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struct ieee80211_supported_band *sband = wiphy->bands[band];
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if (!sband)
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continue;
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for (i = 0; i < sband->n_channels; i++) {
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struct ieee80211_channel *chan = &sband->channels[i];
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if (chan->flags & IEEE80211_CHAN_DISABLED)
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continue;
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if (!wiphy_freq_limits_valid_chan(wiphy, freq_limits,
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n_freq_limits,
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chan)) {
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pr_debug("Disabling freq %d MHz as it's out of OF limits\n",
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chan->center_freq);
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chan->flags |= IEEE80211_CHAN_DISABLED;
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}
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}
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}
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}
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void wiphy_read_of_freq_limits(struct wiphy *wiphy)
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{
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struct device *dev = wiphy_dev(wiphy);
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struct device_node *np;
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struct property *prop;
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struct ieee80211_freq_range *freq_limits;
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unsigned int n_freq_limits;
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const __be32 *p;
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int len, i;
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int err = 0;
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if (!dev)
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return;
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np = dev_of_node(dev);
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if (!np)
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return;
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prop = of_find_property(np, "ieee80211-freq-limit", &len);
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if (!prop)
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return;
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if (!len || len % sizeof(u32) || len / sizeof(u32) % 2) {
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dev_err(dev, "ieee80211-freq-limit wrong format");
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return;
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}
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n_freq_limits = len / sizeof(u32) / 2;
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freq_limits = kcalloc(n_freq_limits, sizeof(*freq_limits), GFP_KERNEL);
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if (!freq_limits) {
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err = -ENOMEM;
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goto out_kfree;
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}
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p = NULL;
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for (i = 0; i < n_freq_limits; i++) {
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struct ieee80211_freq_range *limit = &freq_limits[i];
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p = of_prop_next_u32(prop, p, &limit->start_freq_khz);
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if (!p) {
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err = -EINVAL;
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goto out_kfree;
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}
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p = of_prop_next_u32(prop, p, &limit->end_freq_khz);
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if (!p) {
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err = -EINVAL;
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goto out_kfree;
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}
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if (!limit->start_freq_khz ||
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!limit->end_freq_khz ||
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limit->start_freq_khz >= limit->end_freq_khz) {
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err = -EINVAL;
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goto out_kfree;
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}
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}
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wiphy_freq_limits_apply(wiphy, freq_limits, n_freq_limits);
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out_kfree:
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kfree(freq_limits);
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if (err)
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dev_err(dev, "Failed to get limits: %d\n", err);
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}
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EXPORT_SYMBOL(wiphy_read_of_freq_limits);
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