tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * UWB radio (channel) management.
3 *
4 * Copyright (C) 2008 Cambridge Silicon Radio Ltd.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License version
8 * 2 as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
17 */
18#include <linux/kernel.h>
19#include <linux/uwb.h>
20#include <linux/export.h>
21
22#include "uwb-internal.h"
23
24
25static int uwb_radio_select_channel(struct uwb_rc *rc)
26{
27 /*
28 * Default to channel 9 (BG1, TFC1) unless the user has
29 * selected a specific channel or there are no active PALs.
30 */
31 if (rc->active_pals == 0)
32 return -1;
33 if (rc->beaconing_forced)
34 return rc->beaconing_forced;
35 return 9;
36}
37
38
39/*
40 * Notify all active PALs that the channel has changed.
41 */
42static void uwb_radio_channel_changed(struct uwb_rc *rc, int channel)
43{
44 struct uwb_pal *pal;
45
46 list_for_each_entry(pal, &rc->pals, node) {
47 if (pal->channel && channel != pal->channel) {
48 pal->channel = channel;
49 if (pal->channel_changed)
50 pal->channel_changed(pal, pal->channel);
51 }
52 }
53}
54
55/*
56 * Change to a new channel and notify any active PALs of the new
57 * channel.
58 *
59 * When stopping the radio, PALs need to be notified first so they can
60 * terminate any active reservations.
61 */
62static int uwb_radio_change_channel(struct uwb_rc *rc, int channel)
63{
64 int ret = 0;
65
66 if (channel == -1)
67 uwb_radio_channel_changed(rc, channel);
68
69 if (channel != rc->beaconing) {
70 if (rc->beaconing != -1 && channel != -1) {
71 /*
72 * FIXME: should signal the channel change
73 * with a Channel Change IE.
74 */
75 ret = uwb_radio_change_channel(rc, -1);
76 if (ret < 0)
77 return ret;
78 }
79 ret = uwb_rc_beacon(rc, channel, 0);
80 }
81
82 if (channel != -1)
83 uwb_radio_channel_changed(rc, rc->beaconing);
84
85 return ret;
86}
87
88/**
89 * uwb_radio_start - request that the radio be started
90 * @pal: the PAL making the request.
91 *
92 * If the radio is not already active, aa suitable channel is selected
93 * and beacons are started.
94 */
95int uwb_radio_start(struct uwb_pal *pal)
96{
97 struct uwb_rc *rc = pal->rc;
98 int ret = 0;
99
100 mutex_lock(&rc->uwb_dev.mutex);
101
102 if (!pal->channel) {
103 pal->channel = -1;
104 rc->active_pals++;
105 ret = uwb_radio_change_channel(rc, uwb_radio_select_channel(rc));
106 }
107
108 mutex_unlock(&rc->uwb_dev.mutex);
109 return ret;
110}
111EXPORT_SYMBOL_GPL(uwb_radio_start);
112
113/**
114 * uwb_radio_stop - request tha the radio be stopped.
115 * @pal: the PAL making the request.
116 *
117 * Stops the radio if no other PAL is making use of it.
118 */
119void uwb_radio_stop(struct uwb_pal *pal)
120{
121 struct uwb_rc *rc = pal->rc;
122
123 mutex_lock(&rc->uwb_dev.mutex);
124
125 if (pal->channel) {
126 rc->active_pals--;
127 uwb_radio_change_channel(rc, uwb_radio_select_channel(rc));
128 pal->channel = 0;
129 }
130
131 mutex_unlock(&rc->uwb_dev.mutex);
132}
133EXPORT_SYMBOL_GPL(uwb_radio_stop);
134
135/*
136 * uwb_radio_force_channel - force a specific channel to be used
137 * @rc: the radio controller.
138 * @channel: the channel to use; -1 to force the radio to stop; 0 to
139 * use the default channel selection algorithm.
140 */
141int uwb_radio_force_channel(struct uwb_rc *rc, int channel)
142{
143 int ret = 0;
144
145 mutex_lock(&rc->uwb_dev.mutex);
146
147 rc->beaconing_forced = channel;
148 ret = uwb_radio_change_channel(rc, uwb_radio_select_channel(rc));
149
150 mutex_unlock(&rc->uwb_dev.mutex);
151 return ret;
152}
153
154/*
155 * uwb_radio_setup - setup the radio manager
156 * @rc: the radio controller.
157 *
158 * The radio controller is reset to ensure it's in a known state
159 * before it's used.
160 */
161int uwb_radio_setup(struct uwb_rc *rc)
162{
163 return uwb_rc_reset(rc);
164}
165
166/*
167 * uwb_radio_reset_state - reset any radio manager state
168 * @rc: the radio controller.
169 *
170 * All internal radio manager state is reset to values corresponding
171 * to a reset radio controller.
172 */
173void uwb_radio_reset_state(struct uwb_rc *rc)
174{
175 struct uwb_pal *pal;
176
177 mutex_lock(&rc->uwb_dev.mutex);
178
179 list_for_each_entry(pal, &rc->pals, node) {
180 if (pal->channel) {
181 pal->channel = -1;
182 if (pal->channel_changed)
183 pal->channel_changed(pal, -1);
184 }
185 }
186
187 rc->beaconing = -1;
188 rc->scanning = -1;
189
190 mutex_unlock(&rc->uwb_dev.mutex);
191}
192
193/*
194 * uwb_radio_shutdown - shutdown the radio manager
195 * @rc: the radio controller.
196 *
197 * The radio controller is reset.
198 */
199void uwb_radio_shutdown(struct uwb_rc *rc)
200{
201 uwb_radio_reset_state(rc);
202 uwb_rc_reset(rc);
203}