diff options
Diffstat (limited to 'drivers/uwb/radio.c')
| -rw-r--r-- | drivers/uwb/radio.c | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/drivers/uwb/radio.c b/drivers/uwb/radio.c new file mode 100644 index 000000000..2427e9448 --- /dev/null +++ b/drivers/uwb/radio.c @@ -0,0 +1,207 @@ +/* + * UWB radio (channel) management. + * + * Copyright (C) 2008 Cambridge Silicon Radio Ltd. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License version + * 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +#include <linux/kernel.h> +#include <linux/uwb.h> +#include <linux/export.h> + +#include "uwb-internal.h" + + +static int uwb_radio_select_channel(struct uwb_rc *rc) +{ + /* + * Default to channel 9 (BG1, TFC1) unless the user has + * selected a specific channel or there are no active PALs. + */ + if (rc->active_pals == 0) + return -1; + if (rc->beaconing_forced) + return rc->beaconing_forced; + return 9; +} + + +/* + * Notify all active PALs that the channel has changed. + */ +static void uwb_radio_channel_changed(struct uwb_rc *rc, int channel) +{ + struct uwb_pal *pal; + + list_for_each_entry(pal, &rc->pals, node) { + if (pal->channel && channel != pal->channel) { + pal->channel = channel; + if (pal->channel_changed) + pal->channel_changed(pal, pal->channel); + } + } +} + +/* + * Change to a new channel and notify any active PALs of the new + * channel. + * + * When stopping the radio, PALs need to be notified first so they can + * terminate any active reservations. + */ +static int uwb_radio_change_channel(struct uwb_rc *rc, int channel) +{ + int ret = 0; + struct device *dev = &rc->uwb_dev.dev; + + dev_dbg(dev, "%s: channel = %d, rc->beaconing = %d\n", __func__, + channel, rc->beaconing); + + if (channel == -1) + uwb_radio_channel_changed(rc, channel); + + if (channel != rc->beaconing) { + if (rc->beaconing != -1 && channel != -1) { + /* + * FIXME: should signal the channel change + * with a Channel Change IE. + */ + ret = uwb_radio_change_channel(rc, -1); + if (ret < 0) + return ret; + } + ret = uwb_rc_beacon(rc, channel, 0); + } + + if (channel != -1) + uwb_radio_channel_changed(rc, rc->beaconing); + + return ret; +} + +/** + * uwb_radio_start - request that the radio be started + * @pal: the PAL making the request. + * + * If the radio is not already active, a suitable channel is selected + * and beacons are started. + */ +int uwb_radio_start(struct uwb_pal *pal) +{ + struct uwb_rc *rc = pal->rc; + int ret = 0; + + mutex_lock(&rc->uwb_dev.mutex); + + if (!pal->channel) { + pal->channel = -1; + rc->active_pals++; + ret = uwb_radio_change_channel(rc, uwb_radio_select_channel(rc)); + } + + mutex_unlock(&rc->uwb_dev.mutex); + return ret; +} +EXPORT_SYMBOL_GPL(uwb_radio_start); + +/** + * uwb_radio_stop - request that the radio be stopped. + * @pal: the PAL making the request. + * + * Stops the radio if no other PAL is making use of it. + */ +void uwb_radio_stop(struct uwb_pal *pal) +{ + struct uwb_rc *rc = pal->rc; + + mutex_lock(&rc->uwb_dev.mutex); + + if (pal->channel) { + rc->active_pals--; + uwb_radio_change_channel(rc, uwb_radio_select_channel(rc)); + pal->channel = 0; + } + + mutex_unlock(&rc->uwb_dev.mutex); +} +EXPORT_SYMBOL_GPL(uwb_radio_stop); + +/* + * uwb_radio_force_channel - force a specific channel to be used + * @rc: the radio controller. + * @channel: the channel to use; -1 to force the radio to stop; 0 to + * use the default channel selection algorithm. + */ +int uwb_radio_force_channel(struct uwb_rc *rc, int channel) +{ + int ret = 0; + + mutex_lock(&rc->uwb_dev.mutex); + + rc->beaconing_forced = channel; + ret = uwb_radio_change_channel(rc, uwb_radio_select_channel(rc)); + + mutex_unlock(&rc->uwb_dev.mutex); + return ret; +} + +/* + * uwb_radio_setup - setup the radio manager + * @rc: the radio controller. + * + * The radio controller is reset to ensure it's in a known state + * before it's used. + */ +int uwb_radio_setup(struct uwb_rc *rc) +{ + return uwb_rc_reset(rc); +} + +/* + * uwb_radio_reset_state - reset any radio manager state + * @rc: the radio controller. + * + * All internal radio manager state is reset to values corresponding + * to a reset radio controller. + */ +void uwb_radio_reset_state(struct uwb_rc *rc) +{ + struct uwb_pal *pal; + + mutex_lock(&rc->uwb_dev.mutex); + + list_for_each_entry(pal, &rc->pals, node) { + if (pal->channel) { + pal->channel = -1; + if (pal->channel_changed) + pal->channel_changed(pal, -1); + } + } + + rc->beaconing = -1; + rc->scanning = -1; + + mutex_unlock(&rc->uwb_dev.mutex); +} + +/* + * uwb_radio_shutdown - shutdown the radio manager + * @rc: the radio controller. + * + * The radio controller is reset. + */ +void uwb_radio_shutdown(struct uwb_rc *rc) +{ + uwb_radio_reset_state(rc); + uwb_rc_reset(rc); +} |