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6fae35f9 DV |
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 | ||
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 | */ | |
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 | */ | |
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 | */ | |
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 | */ | |
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 | */ | |
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 | */ | |
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 | */ | |
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 | */ | |
198 | void uwb_radio_shutdown(struct uwb_rc *rc) | |
199 | { | |
200 | uwb_radio_reset_state(rc); | |
201 | uwb_rc_reset(rc); | |
202 | } |