188626f17c
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>
212 lines
6.3 KiB
Diff
212 lines
6.3 KiB
Diff
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
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Date: Wed, 4 Jan 2017 18:58:31 +0100
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Subject: [PATCH] cfg80211: support ieee80211-freq-limit DT property
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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This patch adds a helper for reading that new property and applying
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limitations of supported channels specified this way.
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It is used with devices that normally support a wide wireless band but
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in a given config are limited to some part of it (usually due to board
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design). For example a dual-band chipset may be able to support one band
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only because of used antennas.
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It's also common that tri-band routers have separated radios for lower
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and higher part of 5 GHz band and it may be impossible to say which is
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which without a DT info.
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Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
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[add new function to documentation, fix link]
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Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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---
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create mode 100644 net/wireless/of.c
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--- a/include/net/cfg80211.h
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+++ b/include/net/cfg80211.h
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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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+
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/*
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* Wireless hardware/device configuration structures and methods
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*/
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--- a/net/wireless/Makefile
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+++ b/net/wireless/Makefile
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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-$(CPTCFG_CFG80211_DEBUGFS) += debugfs.o
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cfg80211-$(CPTCFG_CFG80211_WEXT) += wext-compat.o wext-sme.o
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cfg80211-$(CPTCFG_CFG80211_INTERNAL_REGDB) += regdb.o
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--- /dev/null
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+++ b/net/wireless/of.c
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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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+
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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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+
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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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+
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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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+
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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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+
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+ return false;
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+}
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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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+
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+ if (WARN_ON(!n_freq_limits))
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+ return;
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+
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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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+
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+ if (!sband)
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+ continue;
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+
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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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+
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+ if (chan->flags & IEEE80211_CHAN_DISABLED)
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+ continue;
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+
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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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+
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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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+
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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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+
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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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+
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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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+
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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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+
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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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+
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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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+
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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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+
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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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+
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+ wiphy_freq_limits_apply(wiphy, freq_limits, n_freq_limits);
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+
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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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