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 
wiphy_freq_limits_valid_chan(struct wiphy * wiphy,struct ieee80211_freq_range * freq_limits,unsigned int n_freq_limits,struct ieee80211_channel * chan)21 static 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 
wiphy_freq_limits_apply(struct wiphy * wiphy,struct ieee80211_freq_range * freq_limits,unsigned int n_freq_limits)41 static 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 
wiphy_read_of_freq_limits(struct wiphy * wiphy)74 void 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 
133 out_kfree:
134 	kfree(freq_limits);
135 	if (err)
136 		dev_err(dev, "Failed to get limits: %d\n", err);
137 }
138 EXPORT_SYMBOL(wiphy_read_of_freq_limits);
139