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 struct device *dev = &rc->uwb_dev.dev;
66
67 dev_dbg(dev, "%s: channel = %d, rc->beaconing = %d\n", __func__,
68 channel, rc->beaconing);
69
70 if (channel == -1)
71 uwb_radio_channel_changed(rc, channel);
72
73 if (channel != rc->beaconing) {
74 if (rc->beaconing != -1 && channel != -1) {
75 /*
76 * FIXME: should signal the channel change
77 * with a Channel Change IE.
78 */
79 ret = uwb_radio_change_channel(rc, -1);
80 if (ret < 0)
81 return ret;
82 }
83 ret = uwb_rc_beacon(rc, channel, 0);
84 }
85
86 if (channel != -1)
87 uwb_radio_channel_changed(rc, rc->beaconing);
88
89 return ret;
90}
91
92/**
93 * uwb_radio_start - request that the radio be started
94 * @pal: the PAL making the request.
95 *
96 * If the radio is not already active, a suitable channel is selected
97 * and beacons are started.
98 */
99int uwb_radio_start(struct uwb_pal *pal)
100{
101 struct uwb_rc *rc = pal->rc;
102 int ret = 0;
103
104 mutex_lock(&rc->uwb_dev.mutex);
105
106 if (!pal->channel) {
107 pal->channel = -1;
108 rc->active_pals++;
109 ret = uwb_radio_change_channel(rc, uwb_radio_select_channel(rc));
110 }
111
112 mutex_unlock(&rc->uwb_dev.mutex);
113 return ret;
114}
115EXPORT_SYMBOL_GPL(uwb_radio_start);
116
117/**
118 * uwb_radio_stop - request that the radio be stopped.
119 * @pal: the PAL making the request.
120 *
121 * Stops the radio if no other PAL is making use of it.
122 */
123void uwb_radio_stop(struct uwb_pal *pal)
124{
125 struct uwb_rc *rc = pal->rc;
126
127 mutex_lock(&rc->uwb_dev.mutex);
128
129 if (pal->channel) {
130 rc->active_pals--;
131 uwb_radio_change_channel(rc, uwb_radio_select_channel(rc));
132 pal->channel = 0;
133 }
134
135 mutex_unlock(&rc->uwb_dev.mutex);
136}
137EXPORT_SYMBOL_GPL(uwb_radio_stop);
138
139/*
140 * uwb_radio_force_channel - force a specific channel to be used
141 * @rc: the radio controller.
142 * @channel: the channel to use; -1 to force the radio to stop; 0 to
143 * use the default channel selection algorithm.
144 */
145int uwb_radio_force_channel(struct uwb_rc *rc, int channel)
146{
147 int ret = 0;
148
149 mutex_lock(&rc->uwb_dev.mutex);
150
151 rc->beaconing_forced = channel;
152 ret = uwb_radio_change_channel(rc, uwb_radio_select_channel(rc));
153
154 mutex_unlock(&rc->uwb_dev.mutex);
155 return ret;
156}
157
158/*
159 * uwb_radio_setup - setup the radio manager
160 * @rc: the radio controller.
161 *
162 * The radio controller is reset to ensure it's in a known state
163 * before it's used.
164 */
165int uwb_radio_setup(struct uwb_rc *rc)
166{
167 return uwb_rc_reset(rc);
168}
169
170/*
171 * uwb_radio_reset_state - reset any radio manager state
172 * @rc: the radio controller.
173 *
174 * All internal radio manager state is reset to values corresponding
175 * to a reset radio controller.
176 */
177void uwb_radio_reset_state(struct uwb_rc *rc)
178{
179 struct uwb_pal *pal;
180
181 mutex_lock(&rc->uwb_dev.mutex);
182
183 list_for_each_entry(pal, &rc->pals, node) {
184 if (pal->channel) {
185 pal->channel = -1;
186 if (pal->channel_changed)
187 pal->channel_changed(pal, -1);
188 }
189 }
190
191 rc->beaconing = -1;
192 rc->scanning = -1;
193
194 mutex_unlock(&rc->uwb_dev.mutex);
195}
196
197/*
198 * uwb_radio_shutdown - shutdown the radio manager
199 * @rc: the radio controller.
200 *
201 * The radio controller is reset.
202 */
203void uwb_radio_shutdown(struct uwb_rc *rc)
204{
205 uwb_radio_reset_state(rc);
206 uwb_rc_reset(rc);
207}
208