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