/* * 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; 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, aa 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 tha 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); }