forked from luck/tmp_suning_uos_patched
a899575191
This patch fixes a race condition that caused the HWA_HC interface probe function to occasionally fail. The HWA_HC would attempt to register itself with the HWA_RC by searching for a uwb_rc class device with the same parent device ptr. If the probe function for the HWA_RC interface had yet to run, the uwb_rc class device would not have been created causing the look up to fail and the HWA_HC probe function to return an error causing the device to be unusable. The fix is for the HWA to delay registering with the HWA_RC until receiving the command from userspace to start the wireless channel. It is the responsibility of userspace to ensure that the uwb_rc class device has been created before starting the HWA channel. Signed-off-by: Thomas Pugliese <thomas.pugliese@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
102 lines
2.4 KiB
C
102 lines
2.4 KiB
C
/*
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* UWB PAL support.
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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/debugfs.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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/**
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* uwb_pal_init - initialize a UWB PAL
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* @pal: the PAL to initialize
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*/
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void uwb_pal_init(struct uwb_pal *pal)
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{
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INIT_LIST_HEAD(&pal->node);
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}
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EXPORT_SYMBOL_GPL(uwb_pal_init);
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/**
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* uwb_pal_register - register a UWB PAL
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* @pal: the PAL
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*
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* The PAL must be initialized with uwb_pal_init().
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*/
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int uwb_pal_register(struct uwb_pal *pal)
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{
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struct uwb_rc *rc = pal->rc;
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int ret;
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if (pal->device) {
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/* create a link to the uwb_rc in the PAL device's directory. */
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ret = sysfs_create_link(&pal->device->kobj,
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&rc->uwb_dev.dev.kobj, "uwb_rc");
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if (ret < 0)
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return ret;
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/* create a link to the PAL in the UWB device's directory. */
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ret = sysfs_create_link(&rc->uwb_dev.dev.kobj,
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&pal->device->kobj, pal->name);
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if (ret < 0) {
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sysfs_remove_link(&pal->device->kobj, "uwb_rc");
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return ret;
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}
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}
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pal->debugfs_dir = uwb_dbg_create_pal_dir(pal);
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mutex_lock(&rc->uwb_dev.mutex);
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list_add(&pal->node, &rc->pals);
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mutex_unlock(&rc->uwb_dev.mutex);
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return 0;
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}
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EXPORT_SYMBOL_GPL(uwb_pal_register);
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/**
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* uwb_pal_register - unregister a UWB PAL
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* @pal: the PAL
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*/
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void uwb_pal_unregister(struct uwb_pal *pal)
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{
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struct uwb_rc *rc = pal->rc;
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uwb_radio_stop(pal);
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mutex_lock(&rc->uwb_dev.mutex);
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list_del(&pal->node);
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mutex_unlock(&rc->uwb_dev.mutex);
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debugfs_remove(pal->debugfs_dir);
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if (pal->device) {
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sysfs_remove_link(&rc->uwb_dev.dev.kobj, pal->name);
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sysfs_remove_link(&pal->device->kobj, "uwb_rc");
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}
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}
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EXPORT_SYMBOL_GPL(uwb_pal_unregister);
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/**
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* uwb_rc_pal_init - initialize the PAL related parts of a radio controller
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* @rc: the radio controller
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*/
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void uwb_rc_pal_init(struct uwb_rc *rc)
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{
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INIT_LIST_HEAD(&rc->pals);
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}
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