mac80211: backport cfg80211 support for ieee80211-freq-limit DT property

This property allows specifying extra limits for wireless device in DT.
For a full documentation see upstream commit b330b25eaabd ("dt-bindings:
document common IEEE 802.11 frequency limit property").

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

2 files changed, 312 insertions, 0 deletions

diff --git a/package/kernel/mac80211/patches/347-0001-cfg80211-move-function-checking-range-fit-to-util.c.patch b/package/kernel/mac80211/patches/347-0001-cfg80211-move-function-checking-range-fit-to-util.c.patch
new file mode 100644
index 0000000000..4a50d37b2e
--- /dev/null
+++ b/package/kernel/mac80211/patches/347-0001-cfg80211-move-function-checking-range-fit-to-util.c.patch
@@ -0,0 +1,101 @@
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Wed, 4 Jan 2017 18:58:30 +0100
+Subject: [PATCH] cfg80211: move function checking range fit to util.c
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+It is needed for another cfg80211 helper that will be out of reg.c so
+move it to common util.c file and make it non-static.
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+Signed-off-by: Johannes Berg <johannes.berg@intel.com>
+---
+
+--- a/net/wireless/core.h
++++ b/net/wireless/core.h
+@@ -429,6 +429,9 @@ int cfg80211_change_iface(struct cfg8021
+ void cfg80211_process_rdev_events(struct cfg80211_registered_device *rdev);
+ void cfg80211_process_wdev_events(struct wireless_dev *wdev);
+ 
++bool cfg80211_does_bw_fit_range(const struct ieee80211_freq_range *freq_range,
++				u32 center_freq_khz, u32 bw_khz);
++
+ /**
+  * cfg80211_chandef_dfs_usable - checks if chandef is DFS usable
+  * @wiphy: the wiphy to validate against
+--- a/net/wireless/reg.c
++++ b/net/wireless/reg.c
+@@ -748,21 +748,6 @@ static bool is_valid_rd(const struct iee
+ 	return true;
+ }
+ 
+-static bool reg_does_bw_fit(const struct ieee80211_freq_range *freq_range,
+-			    u32 center_freq_khz, u32 bw_khz)
+-{
+-	u32 start_freq_khz, end_freq_khz;
+-
+-	start_freq_khz = center_freq_khz - (bw_khz/2);
+-	end_freq_khz = center_freq_khz + (bw_khz/2);
+-
+-	if (start_freq_khz >= freq_range->start_freq_khz &&
+-	    end_freq_khz <= freq_range->end_freq_khz)
+-		return true;
+-
+-	return false;
+-}
+-
+ /**
+  * freq_in_rule_band - tells us if a frequency is in a frequency band
+  * @freq_range: frequency rule we want to query
+@@ -1070,7 +1055,7 @@ freq_reg_info_regd(u32 center_freq,
+ 		if (!band_rule_found)
+ 			band_rule_found = freq_in_rule_band(fr, center_freq);
+ 
+-		bw_fits = reg_does_bw_fit(fr, center_freq, bw);
++		bw_fits = cfg80211_does_bw_fit_range(fr, center_freq, bw);
+ 
+ 		if (band_rule_found && bw_fits)
+ 			return rr;
+@@ -1138,11 +1123,13 @@ static uint32_t reg_rule_to_chan_bw_flag
+ 		max_bandwidth_khz = reg_get_max_bandwidth(regd, reg_rule);
+ 
+ 	/* If we get a reg_rule we can assume that at least 5Mhz fit */
+-	if (!reg_does_bw_fit(freq_range, MHZ_TO_KHZ(chan->center_freq),
+-			     MHZ_TO_KHZ(10)))
++	if (!cfg80211_does_bw_fit_range(freq_range,
++					MHZ_TO_KHZ(chan->center_freq),
++					MHZ_TO_KHZ(10)))
+ 		bw_flags |= IEEE80211_CHAN_NO_10MHZ;
+-	if (!reg_does_bw_fit(freq_range, MHZ_TO_KHZ(chan->center_freq),
+-			     MHZ_TO_KHZ(20)))
++	if (!cfg80211_does_bw_fit_range(freq_range,
++					MHZ_TO_KHZ(chan->center_freq),
++					MHZ_TO_KHZ(20)))
+ 		bw_flags |= IEEE80211_CHAN_NO_20MHZ;
+ 
+ 	if (max_bandwidth_khz < MHZ_TO_KHZ(10))
+--- a/net/wireless/util.c
++++ b/net/wireless/util.c
+@@ -1788,6 +1788,21 @@ void cfg80211_free_nan_func(struct cfg80
+ }
+ EXPORT_SYMBOL(cfg80211_free_nan_func);
+ 
++bool cfg80211_does_bw_fit_range(const struct ieee80211_freq_range *freq_range,
++				u32 center_freq_khz, u32 bw_khz)
++{
++	u32 start_freq_khz, end_freq_khz;
++
++	start_freq_khz = center_freq_khz - (bw_khz / 2);
++	end_freq_khz = center_freq_khz + (bw_khz / 2);
++
++	if (start_freq_khz >= freq_range->start_freq_khz &&
++	    end_freq_khz <= freq_range->end_freq_khz)
++		return true;
++
++	return false;
++}
++
+ /* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
+ /* Ethernet-II snap header (RFC1042 for most EtherTypes) */
+ const unsigned char rfc1042_header[] __aligned(2) =
diff --git a/package/kernel/mac80211/patches/347-0002-cfg80211-support-ieee80211-freq-limit-DT-property.patch b/package/kernel/mac80211/patches/347-0002-cfg80211-support-ieee80211-freq-limit-DT-property.patch
new file mode 100644
index 0000000000..3e1aae72db
--- /dev/null
+++ b/package/kernel/mac80211/patches/347-0002-cfg80211-support-ieee80211-freq-limit-DT-property.patch
@@ -0,0 +1,211 @@
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Wed, 4 Jan 2017 18:58:31 +0100
+Subject: [PATCH] cfg80211: support ieee80211-freq-limit DT property
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+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>
+---
+ create mode 100644 net/wireless/of.c
+
+--- a/include/net/cfg80211.h
++++ b/include/net/cfg80211.h
+@@ -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
+  */
+--- a/net/wireless/Makefile
++++ b/net/wireless/Makefile
+@@ -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-$(CPTCFG_CFG80211_DEBUGFS) += debugfs.o
+ cfg80211-$(CPTCFG_CFG80211_WEXT) += wext-compat.o wext-sme.o
+ cfg80211-$(CPTCFG_CFG80211_INTERNAL_REGDB) += regdb.o
+--- /dev/null
++++ b/net/wireless/of.c
+@@ -0,0 +1,138 @@
++/*
++ * 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);