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