1/*
  2 * Copyright (C) 2017 Rafał Miłecki <rafal@milecki.pl>
  3 *
  4 * Permission to use, copy, modify, and/or distribute this software for any
  5 * purpose with or without fee is hereby granted, provided that the above
  6 * copyright notice and this permission notice appear in all copies.
  7 *
  8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 15 */
 16
 17#include <linux/of.h>
 18#include <net/cfg80211.h>
 19#include "core.h"
 20
 21static bool wiphy_freq_limits_valid_chan(struct wiphy *wiphy,
 22					 struct ieee80211_freq_range *freq_limits,
 23					 unsigned int n_freq_limits,
 24					 struct ieee80211_channel *chan)
 25{
 26	u32 bw = MHZ_TO_KHZ(20);
 27	int i;
 28
 29	for (i = 0; i < n_freq_limits; i++) {
 30		struct ieee80211_freq_range *limit = &freq_limits[i];
 31
 32		if (cfg80211_does_bw_fit_range(limit,
 33					       MHZ_TO_KHZ(chan->center_freq),
 34					       bw))
 35			return true;
 36	}
 37
 38	return false;
 39}
 40
 41static void wiphy_freq_limits_apply(struct wiphy *wiphy,
 42				    struct ieee80211_freq_range *freq_limits,
 43				    unsigned int n_freq_limits)
 44{
 45	enum nl80211_band band;
 46	int i;
 47
 48	if (WARN_ON(!n_freq_limits))
 49		return;
 50
 51	for (band = 0; band < NUM_NL80211_BANDS; band++) {
 52		struct ieee80211_supported_band *sband = wiphy->bands[band];
 53
 54		if (!sband)
 55			continue;
 56
 57		for (i = 0; i < sband->n_channels; i++) {
 58			struct ieee80211_channel *chan = &sband->channels[i];
 59
 60			if (chan->flags & IEEE80211_CHAN_DISABLED)
 61				continue;
 62
 63			if (!wiphy_freq_limits_valid_chan(wiphy, freq_limits,
 64							  n_freq_limits,
 65							  chan)) {
 66				pr_debug("Disabling freq %d MHz as it's out of OF limits\n",
 67					 chan->center_freq);
 68				chan->flags |= IEEE80211_CHAN_DISABLED;
 69			}
 70		}
 71	}
 72}
 73
 74void wiphy_read_of_freq_limits(struct wiphy *wiphy)
 75{
 76	struct device *dev = wiphy_dev(wiphy);
 77	struct device_node *np;
 78	struct property *prop;
 79	struct ieee80211_freq_range *freq_limits;
 80	unsigned int n_freq_limits;
 81	const __be32 *p;
 82	int len, i;
 83	int err = 0;
 84
 85	if (!dev)
 86		return;
 87	np = dev_of_node(dev);
 88	if (!np)
 89		return;
 90
 91	prop = of_find_property(np, "ieee80211-freq-limit", &len);
 92	if (!prop)
 93		return;
 94
 95	if (!len || len % sizeof(u32) || len / sizeof(u32) % 2) {
 96		dev_err(dev, "ieee80211-freq-limit wrong format");
 97		return;
 98	}
 99	n_freq_limits = len / sizeof(u32) / 2;
100
101	freq_limits = kcalloc(n_freq_limits, sizeof(*freq_limits), GFP_KERNEL);
102	if (!freq_limits) {
103		err = -ENOMEM;
104		goto out_kfree;
105	}
106
107	p = NULL;
108	for (i = 0; i < n_freq_limits; i++) {
109		struct ieee80211_freq_range *limit = &freq_limits[i];
110
111		p = of_prop_next_u32(prop, p, &limit->start_freq_khz);
112		if (!p) {
113			err = -EINVAL;
114			goto out_kfree;
115		}
116
117		p = of_prop_next_u32(prop, p, &limit->end_freq_khz);
118		if (!p) {
119			err = -EINVAL;
120			goto out_kfree;
121		}
122
123		if (!limit->start_freq_khz ||
124		    !limit->end_freq_khz ||
125		    limit->start_freq_khz >= limit->end_freq_khz) {
126			err = -EINVAL;
127			goto out_kfree;
128		}
129	}
130
131	wiphy_freq_limits_apply(wiphy, freq_limits, n_freq_limits);
132
133out_kfree:
134	kfree(freq_limits);
135	if (err)
136		dev_err(dev, "Failed to get limits: %d\n", err);
137}
138EXPORT_SYMBOL(wiphy_read_of_freq_limits);