aboutsummaryrefslogtreecommitdiff
path: root/drivers/net/wireless/zd1211rw/zd_ieee80211.c
blob: 189160efd2ae45e3265f97baafd40c472224556a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
/* zd_ieee80211.c
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

/*
 * A lot of this code is generic and should be moved into the upper layers
 * at some point.
 */

#include <linux/errno.h>
#include <linux/wireless.h>
#include <linux/kernel.h>
#include <net/ieee80211.h>

#include "zd_def.h"
#include "zd_ieee80211.h"
#include "zd_mac.h"

static const struct channel_range channel_ranges[] = {
	[0]			 = { 0,  0},
	[ZD_REGDOMAIN_FCC]	 = { 1, 12},
	[ZD_REGDOMAIN_IC]	 = { 1, 12},
	[ZD_REGDOMAIN_ETSI]	 = { 1, 14},
	[ZD_REGDOMAIN_JAPAN]	 = { 1, 14},
	[ZD_REGDOMAIN_SPAIN]	 = { 1, 14},
	[ZD_REGDOMAIN_FRANCE]	 = { 1, 14},

	/* Japan originally only had channel 14 available (see CHNL_ID 0x40 in
	 * 802.11). However, in 2001 the range was extended to include channels
	 * 1-13. The ZyDAS devices still use the old region code but are
	 * designed to allow the extra channel access in Japan. */
	[ZD_REGDOMAIN_JAPAN_ADD] = { 1, 15},
};

const struct channel_range *zd_channel_range(u8 regdomain)
{
	if (regdomain >= ARRAY_SIZE(channel_ranges))
		regdomain = 0;
	return &channel_ranges[regdomain];
}

int zd_regdomain_supports_channel(u8 regdomain, u8 channel)
{
	const struct channel_range *range = zd_channel_range(regdomain);
	return range->start <= channel && channel < range->end;
}

int zd_regdomain_supported(u8 regdomain)
{
	const struct channel_range *range = zd_channel_range(regdomain);
	return range->start != 0;
}

/* Stores channel frequencies in MHz. */
static const u16 channel_frequencies[] = {
	2412, 2417, 2422, 2427, 2432, 2437, 2442, 2447,
	2452, 2457, 2462, 2467, 2472, 2484,
};

#define NUM_CHANNELS ARRAY_SIZE(channel_frequencies)

static int compute_freq(struct iw_freq *freq, u32 mhz, u32 hz)
{
	u32 factor;

	freq->e = 0;
	if (mhz >= 1000000000U) {
		pr_debug("zd1211 mhz %u to large\n", mhz);
		freq->m = 0;
		return -EINVAL;
	}

	factor = 1000;
	while (mhz >= factor) {

		freq->e += 1;
		factor *= 10;
	}

	factor /= 1000U;
	freq->m = mhz * (1000000U/factor) + hz/factor;

	return 0;
}

int zd_channel_to_freq(struct iw_freq *freq, u8 channel)
{
	if (channel > NUM_CHANNELS) {
		freq->m = 0;
		freq->e = 0;
		return -EINVAL;
	}
	if (!channel) {
		freq->m = 0;
		freq->e = 0;
		return -EINVAL;
	}
	return compute_freq(freq, channel_frequencies[channel-1], 0);
}

static int freq_to_mhz(const struct iw_freq *freq)
{
	u32 factor;
	int e;

	/* Such high frequencies are not supported. */
	if (freq->e > 6)
		return -EINVAL;

	factor = 1;
	for (e = freq->e; e > 0; --e) {
		factor *= 10;
	}
	factor = 1000000U / factor;

	if (freq->m % factor) {
		return -EINVAL;
	}

	return freq->m / factor;
}

int zd_find_channel(u8 *channel, const struct iw_freq *freq)
{
	int i, r;
	u32 mhz;

	if (freq->m < 1000) {
		if (freq->m  > NUM_CHANNELS || freq->m == 0)
			return -EINVAL;
		*channel = freq->m;
		return 1;
	}

	r = freq_to_mhz(freq);
	if (r < 0)
		return r;
	mhz = r;

	for (i = 0; i < NUM_CHANNELS; i++) {
		if (mhz == channel_frequencies[i]) {
			*channel = i+1;
			return 1;
		}
	}

	return -EINVAL;
}

int zd_geo_init(struct ieee80211_device *ieee, u8 regdomain)
{
	struct ieee80211_geo geo;
	const struct channel_range *range;
	int i;
	u8 channel;

	dev_dbg(zd_mac_dev(zd_netdev_mac(ieee->dev)),
		"regdomain %#04x\n", regdomain);

	range = zd_channel_range(regdomain);
	if (range->start == 0) {
		dev_err(zd_mac_dev(zd_netdev_mac(ieee->dev)),
			"zd1211 regdomain %#04x not supported\n",
			regdomain);
		return -EINVAL;
	}

	memset(&geo, 0, sizeof(geo));

	for (i = 0, channel = range->start; channel < range->end; channel++) {
		struct ieee80211_channel *chan = &geo.bg[i++];
		chan->freq = channel_frequencies[channel - 1];
		chan->channel = channel;
	}

	geo.bg_channels = i;
	memcpy(geo.name, "XX ", 4);
	ieee80211_set_geo(ieee, &geo);
	return 0;
}