Home Home > GIT Browse
summaryrefslogtreecommitdiff
blob: 240dd755927efe0ba626d06cf53e2a757826f63a (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
194
195
196
// SPDX-License-Identifier: GPL-2.0-only
/*
 * UWB radio (channel) management.
 *
 * Copyright (C) 2008 Cambridge Silicon Radio Ltd.
 */
#include <linux/kernel.h>
#include <linux/uwb.h>
#include <linux/export.h>

#include "uwb-internal.h"


static int uwb_radio_select_channel(struct uwb_rc *rc)
{
	/*
	 * Default to channel 9 (BG1, TFC1) unless the user has
	 * selected a specific channel or there are no active PALs.
	 */
	if (rc->active_pals == 0)
		return -1;
	if (rc->beaconing_forced)
		return rc->beaconing_forced;
	return 9;
}


/*
 * Notify all active PALs that the channel has changed.
 */
static void uwb_radio_channel_changed(struct uwb_rc *rc, int channel)
{
	struct uwb_pal *pal;

	list_for_each_entry(pal, &rc->pals, node) {
		if (pal->channel && channel != pal->channel) {
			pal->channel = channel;
			if (pal->channel_changed)
				pal->channel_changed(pal, pal->channel);
		}
	}
}

/*
 * Change to a new channel and notify any active PALs of the new
 * channel.
 *
 * When stopping the radio, PALs need to be notified first so they can
 * terminate any active reservations.
 */
static int uwb_radio_change_channel(struct uwb_rc *rc, int channel)
{
	int ret = 0;
	struct device *dev = &rc->uwb_dev.dev;

	dev_dbg(dev, "%s: channel = %d, rc->beaconing = %d\n", __func__,
		channel, rc->beaconing);

	if (channel == -1)
		uwb_radio_channel_changed(rc, channel);

	if (channel != rc->beaconing) {
		if (rc->beaconing != -1 && channel != -1) {
			/*
			 * FIXME: should signal the channel change
			 * with a Channel Change IE.
			 */
			ret = uwb_radio_change_channel(rc, -1);
			if (ret < 0)
				return ret;
		}
		ret = uwb_rc_beacon(rc, channel, 0);
	}

	if (channel != -1)
		uwb_radio_channel_changed(rc, rc->beaconing);

	return ret;
}

/**
 * uwb_radio_start - request that the radio be started
 * @pal: the PAL making the request.
 *
 * If the radio is not already active, a suitable channel is selected
 * and beacons are started.
 */
int uwb_radio_start(struct uwb_pal *pal)
{
	struct uwb_rc *rc = pal->rc;
	int ret = 0;

	mutex_lock(&rc->uwb_dev.mutex);

	if (!pal->channel) {
		pal->channel = -1;
		rc->active_pals++;
		ret = uwb_radio_change_channel(rc, uwb_radio_select_channel(rc));
	}

	mutex_unlock(&rc->uwb_dev.mutex);
	return ret;
}
EXPORT_SYMBOL_GPL(uwb_radio_start);

/**
 * uwb_radio_stop - request that the radio be stopped.
 * @pal: the PAL making the request.
 *
 * Stops the radio if no other PAL is making use of it.
 */
void uwb_radio_stop(struct uwb_pal *pal)
{
	struct uwb_rc *rc = pal->rc;

	mutex_lock(&rc->uwb_dev.mutex);

	if (pal->channel) {
		rc->active_pals--;
		uwb_radio_change_channel(rc, uwb_radio_select_channel(rc));
		pal->channel = 0;
	}

	mutex_unlock(&rc->uwb_dev.mutex);
}
EXPORT_SYMBOL_GPL(uwb_radio_stop);

/*
 * uwb_radio_force_channel - force a specific channel to be used
 * @rc: the radio controller.
 * @channel: the channel to use; -1 to force the radio to stop; 0 to
 *   use the default channel selection algorithm.
 */
int uwb_radio_force_channel(struct uwb_rc *rc, int channel)
{
	int ret = 0;

	mutex_lock(&rc->uwb_dev.mutex);

	rc->beaconing_forced = channel;
	ret = uwb_radio_change_channel(rc, uwb_radio_select_channel(rc));

	mutex_unlock(&rc->uwb_dev.mutex);
	return ret;
}

/*
 * uwb_radio_setup - setup the radio manager
 * @rc: the radio controller.
 *
 * The radio controller is reset to ensure it's in a known state
 * before it's used.
 */
int uwb_radio_setup(struct uwb_rc *rc)
{
	return uwb_rc_reset(rc);
}

/*
 * uwb_radio_reset_state - reset any radio manager state
 * @rc: the radio controller.
 *
 * All internal radio manager state is reset to values corresponding
 * to a reset radio controller.
 */
void uwb_radio_reset_state(struct uwb_rc *rc)
{
	struct uwb_pal *pal;

	mutex_lock(&rc->uwb_dev.mutex);

	list_for_each_entry(pal, &rc->pals, node) {
		if (pal->channel) {
			pal->channel = -1;
			if (pal->channel_changed)
				pal->channel_changed(pal, -1);
		}
	}

	rc->beaconing = -1;
	rc->scanning = -1;

	mutex_unlock(&rc->uwb_dev.mutex);
}

/*
 * uwb_radio_shutdown - shutdown the radio manager
 * @rc: the radio controller.
 *
 * The radio controller is reset.
 */
void uwb_radio_shutdown(struct uwb_rc *rc)
{
	uwb_radio_reset_state(rc);
	uwb_rc_reset(rc);
}