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
21 #include "uwb-internal.h"
22
23
uwb_radio_select_channel(struct uwb_rc * rc)24 static int uwb_radio_select_channel(struct uwb_rc *rc)
25 {
26 /*
27 * Default to channel 9 (BG1, TFC1) unless the user has
28 * selected a specific channel or there are no active PALs.
29 */
30 if (rc->active_pals == 0)
31 return -1;
32 if (rc->beaconing_forced)
33 return rc->beaconing_forced;
34 return 9;
35 }
36
37
38 /*
39 * Notify all active PALs that the channel has changed.
40 */
uwb_radio_channel_changed(struct uwb_rc * rc,int channel)41 static void uwb_radio_channel_changed(struct uwb_rc *rc, int channel)
42 {
43 struct uwb_pal *pal;
44
45 list_for_each_entry(pal, &rc->pals, node) {
46 if (pal->channel && channel != pal->channel) {
47 pal->channel = channel;
48 if (pal->channel_changed)
49 pal->channel_changed(pal, pal->channel);
50 }
51 }
52 }
53
54 /*
55 * Change to a new channel and notify any active PALs of the new
56 * channel.
57 *
58 * When stopping the radio, PALs need to be notified first so they can
59 * terminate any active reservations.
60 */
uwb_radio_change_channel(struct uwb_rc * rc,int channel)61 static int uwb_radio_change_channel(struct uwb_rc *rc, int channel)
62 {
63 int ret = 0;
64
65 if (channel == -1)
66 uwb_radio_channel_changed(rc, channel);
67
68 if (channel != rc->beaconing) {
69 if (rc->beaconing != -1 && channel != -1) {
70 /*
71 * FIXME: should signal the channel change
72 * with a Channel Change IE.
73 */
74 ret = uwb_radio_change_channel(rc, -1);
75 if (ret < 0)
76 return ret;
77 }
78 ret = uwb_rc_beacon(rc, channel, 0);
79 }
80
81 if (channel != -1)
82 uwb_radio_channel_changed(rc, rc->beaconing);
83
84 return ret;
85 }
86
87 /**
88 * uwb_radio_start - request that the radio be started
89 * @pal: the PAL making the request.
90 *
91 * If the radio is not already active, aa suitable channel is selected
92 * and beacons are started.
93 */
uwb_radio_start(struct uwb_pal * pal)94 int uwb_radio_start(struct uwb_pal *pal)
95 {
96 struct uwb_rc *rc = pal->rc;
97 int ret = 0;
98
99 mutex_lock(&rc->uwb_dev.mutex);
100
101 if (!pal->channel) {
102 pal->channel = -1;
103 rc->active_pals++;
104 ret = uwb_radio_change_channel(rc, uwb_radio_select_channel(rc));
105 }
106
107 mutex_unlock(&rc->uwb_dev.mutex);
108 return ret;
109 }
110 EXPORT_SYMBOL_GPL(uwb_radio_start);
111
112 /**
113 * uwb_radio_stop - request tha the radio be stopped.
114 * @pal: the PAL making the request.
115 *
116 * Stops the radio if no other PAL is making use of it.
117 */
uwb_radio_stop(struct uwb_pal * pal)118 void uwb_radio_stop(struct uwb_pal *pal)
119 {
120 struct uwb_rc *rc = pal->rc;
121
122 mutex_lock(&rc->uwb_dev.mutex);
123
124 if (pal->channel) {
125 rc->active_pals--;
126 uwb_radio_change_channel(rc, uwb_radio_select_channel(rc));
127 pal->channel = 0;
128 }
129
130 mutex_unlock(&rc->uwb_dev.mutex);
131 }
132 EXPORT_SYMBOL_GPL(uwb_radio_stop);
133
134 /*
135 * uwb_radio_force_channel - force a specific channel to be used
136 * @rc: the radio controller.
137 * @channel: the channel to use; -1 to force the radio to stop; 0 to
138 * use the default channel selection algorithm.
139 */
uwb_radio_force_channel(struct uwb_rc * rc,int channel)140 int uwb_radio_force_channel(struct uwb_rc *rc, int channel)
141 {
142 int ret = 0;
143
144 mutex_lock(&rc->uwb_dev.mutex);
145
146 rc->beaconing_forced = channel;
147 ret = uwb_radio_change_channel(rc, uwb_radio_select_channel(rc));
148
149 mutex_unlock(&rc->uwb_dev.mutex);
150 return ret;
151 }
152
153 /*
154 * uwb_radio_setup - setup the radio manager
155 * @rc: the radio controller.
156 *
157 * The radio controller is reset to ensure it's in a known state
158 * before it's used.
159 */
uwb_radio_setup(struct uwb_rc * rc)160 int uwb_radio_setup(struct uwb_rc *rc)
161 {
162 return uwb_rc_reset(rc);
163 }
164
165 /*
166 * uwb_radio_reset_state - reset any radio manager state
167 * @rc: the radio controller.
168 *
169 * All internal radio manager state is reset to values corresponding
170 * to a reset radio controller.
171 */
uwb_radio_reset_state(struct uwb_rc * rc)172 void uwb_radio_reset_state(struct uwb_rc *rc)
173 {
174 struct uwb_pal *pal;
175
176 mutex_lock(&rc->uwb_dev.mutex);
177
178 list_for_each_entry(pal, &rc->pals, node) {
179 if (pal->channel) {
180 pal->channel = -1;
181 if (pal->channel_changed)
182 pal->channel_changed(pal, -1);
183 }
184 }
185
186 rc->beaconing = -1;
187 rc->scanning = -1;
188
189 mutex_unlock(&rc->uwb_dev.mutex);
190 }
191
192 /*
193 * uwb_radio_shutdown - shutdown the radio manager
194 * @rc: the radio controller.
195 *
196 * The radio controller is reset.
197 */
uwb_radio_shutdown(struct uwb_rc * rc)198 void uwb_radio_shutdown(struct uwb_rc *rc)
199 {
200 uwb_radio_reset_state(rc);
201 uwb_rc_reset(rc);
202 }
203