Commit e691ac2f authored by Rafał Miłecki's avatar Rafał Miłecki Committed by Johannes Berg
Browse files

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: default avatarRafał Miłecki <rafal@milecki.pl>
[add new function to documentation, fix link]
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 4787cfa0
......@@ -44,6 +44,9 @@ Device registration
.. kernel-doc:: include/net/cfg80211.h
:functions: wiphy_new
.. kernel-doc:: include/net/cfg80211.h
:functions: wiphy_read_of_freq_limits
.. kernel-doc:: include/net/cfg80211.h
:functions: wiphy_register
......
......@@ -311,6 +311,34 @@ struct ieee80211_supported_band {
struct ieee80211_sta_vht_cap vht_cap;
};
/**
* wiphy_read_of_freq_limits - read frequency limits from device tree
*
* @wiphy: the wireless device to get extra limits for
*
* Some devices may have extra limitations specified in DT. This may be useful
* for chipsets that normally support more bands but are limited due to board
* design (e.g. by antennas or external power amplifier).
*
* This function reads info from DT and uses it to *modify* channels (disable
* unavailable ones). It's usually a *bad* idea to use it in drivers with
* shared channel data as DT limitations are device specific. You should make
* sure to call it only if channels in wiphy are copied and can be modified
* without affecting other devices.
*
* As this function access device node it has to be called after set_wiphy_dev.
* It also modifies channels so they have to be set first.
* If using this helper, call it before wiphy_register().
*/
#ifdef CONFIG_OF
void wiphy_read_of_freq_limits(struct wiphy *wiphy);
#else /* CONFIG_OF */
static inline void wiphy_read_of_freq_limits(struct wiphy *wiphy)
{
}
#endif /* !CONFIG_OF */
/*
* Wireless hardware/device configuration structures and methods
*/
......
......@@ -11,6 +11,7 @@ obj-$(CONFIG_WEXT_PRIV) += wext-priv.o
cfg80211-y += core.o sysfs.o radiotap.o util.o reg.o scan.o nl80211.o
cfg80211-y += mlme.o ibss.o sme.o chan.o ethtool.o mesh.o ap.o trace.o ocb.o
cfg80211-$(CONFIG_OF) += of.o
cfg80211-$(CONFIG_CFG80211_DEBUGFS) += debugfs.o
cfg80211-$(CONFIG_CFG80211_WEXT) += wext-compat.o wext-sme.o
cfg80211-$(CONFIG_CFG80211_INTERNAL_REGDB) += regdb.o
......
/*
* Copyright (C) 2017 Rafał Miłecki <rafal@milecki.pl>
*
* 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 <linux/of.h>
#include <net/cfg80211.h>
#include "core.h"
static bool wiphy_freq_limits_valid_chan(struct wiphy *wiphy,
struct ieee80211_freq_range *freq_limits,
unsigned int n_freq_limits,
struct ieee80211_channel *chan)
{
u32 bw = MHZ_TO_KHZ(20);
int i;
for (i = 0; i < n_freq_limits; i++) {
struct ieee80211_freq_range *limit = &freq_limits[i];
if (cfg80211_does_bw_fit_range(limit,
MHZ_TO_KHZ(chan->center_freq),
bw))
return true;
}
return false;
}
static void wiphy_freq_limits_apply(struct wiphy *wiphy,
struct ieee80211_freq_range *freq_limits,
unsigned int n_freq_limits)
{
enum nl80211_band band;
int i;
if (WARN_ON(!n_freq_limits))
return;
for (band = 0; band < NUM_NL80211_BANDS; band++) {
struct ieee80211_supported_band *sband = wiphy->bands[band];
if (!sband)
continue;
for (i = 0; i < sband->n_channels; i++) {
struct ieee80211_channel *chan = &sband->channels[i];
if (chan->flags & IEEE80211_CHAN_DISABLED)
continue;
if (!wiphy_freq_limits_valid_chan(wiphy, freq_limits,
n_freq_limits,
chan)) {
pr_debug("Disabling freq %d MHz as it's out of OF limits\n",
chan->center_freq);
chan->flags |= IEEE80211_CHAN_DISABLED;
}
}
}
}
void wiphy_read_of_freq_limits(struct wiphy *wiphy)
{
struct device *dev = wiphy_dev(wiphy);
struct device_node *np;
struct property *prop;
struct ieee80211_freq_range *freq_limits;
unsigned int n_freq_limits;
const __be32 *p;
int len, i;
int err = 0;
if (!dev)
return;
np = dev_of_node(dev);
if (!np)
return;
prop = of_find_property(np, "ieee80211-freq-limit", &len);
if (!prop)
return;
if (!len || len % sizeof(u32) || len / sizeof(u32) % 2) {
dev_err(dev, "ieee80211-freq-limit wrong format");
return;
}
n_freq_limits = len / sizeof(u32) / 2;
freq_limits = kcalloc(n_freq_limits, sizeof(*freq_limits), GFP_KERNEL);
if (!freq_limits) {
err = -ENOMEM;
goto out_kfree;
}
p = NULL;
for (i = 0; i < n_freq_limits; i++) {
struct ieee80211_freq_range *limit = &freq_limits[i];
p = of_prop_next_u32(prop, p, &limit->start_freq_khz);
if (!p) {
err = -EINVAL;
goto out_kfree;
}
p = of_prop_next_u32(prop, p, &limit->end_freq_khz);
if (!p) {
err = -EINVAL;
goto out_kfree;
}
if (!limit->start_freq_khz ||
!limit->end_freq_khz ||
limit->start_freq_khz >= limit->end_freq_khz) {
err = -EINVAL;
goto out_kfree;
}
}
wiphy_freq_limits_apply(wiphy, freq_limits, n_freq_limits);
out_kfree:
kfree(freq_limits);
if (err)
dev_err(dev, "Failed to get limits: %d\n", err);
}
EXPORT_SYMBOL(wiphy_read_of_freq_limits);
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