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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> | |
475c0a6b | 20 | #include <linux/export.h> |
6fae35f9 DV |
21 | |
22 | #include "uwb-internal.h" | |
23 | ||
24 | ||
25 | static 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 | */ | |
42 | static 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 | */ | |
62 | static int uwb_radio_change_channel(struct uwb_rc *rc, int channel) | |
63 | { | |
64 | int ret = 0; | |
f79833a7 TP |
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); | |
6fae35f9 DV |
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 | * | |
67d0fb25 | 96 | * If the radio is not already active, a suitable channel is selected |
6fae35f9 DV |
97 | * and beacons are started. |
98 | */ | |
99 | int 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 | } | |
115 | EXPORT_SYMBOL_GPL(uwb_radio_start); | |
116 | ||
117 | /** | |
99280164 | 118 | * uwb_radio_stop - request that the radio be stopped. |
6fae35f9 DV |
119 | * @pal: the PAL making the request. |
120 | * | |
121 | * Stops the radio if no other PAL is making use of it. | |
122 | */ | |
123 | void 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 | } | |
137 | EXPORT_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 | */ | |
145 | int 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 | */ | |
165 | int 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 | */ | |
177 | void 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 | */ | |
203 | void uwb_radio_shutdown(struct uwb_rc *rc) | |
204 | { | |
205 | uwb_radio_reset_state(rc); | |
206 | uwb_rc_reset(rc); | |
207 | } |