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/************************************************************************************
*
* Copyright (C) 2009-2011 Broadcom Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNOppU General Public License, version 2, as published by
* the Free Software Foundation (the "GPL").
*
* 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.
*
* A copy of the GPL is available at http://www.broadcom.com/licenses/GPLv2.php,
* or by writing to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*
************************************************************************************/
#include <linux/poll.h>
#include <linux/miscdevice.h>
#include <linux/hid.h>
#include <linux/sched.h>
MODULE_AUTHOR("Wenbin Yu <wenbinyu@broadcom.com>");
MODULE_DESCRIPTION("User level driver support for BT lock");
MODULE_SUPPORTED_DEVICE("btlock");
MODULE_LICENSE("GPL");
#define BTLOCK_NAME "btlock"
#define BTLOCK_MINOR 224
#define PR(msg, ...) printk("#### %s " msg, current->comm, ##__VA_ARGS__)
struct btlock {
int lock;
int cookie;
};
static struct semaphore lock;
static int owner_cookie;
static int btlock_open(struct inode *inode, struct file *file)
{
return 0;
}
static int btlock_release(struct inode *inode, struct file *file)
{
return 0;
}
static ssize_t btlock_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
struct btlock lock_para;
ssize_t ret = 0;
char cookie_msg[5] = {0};
char owner_msg[5] = {0};
if (count < sizeof(struct btlock))
return -EINVAL;
if (copy_from_user(&lock_para, buffer, sizeof(struct btlock))) {
return -EFAULT;
}
memcpy(cookie_msg, &lock_para.cookie, sizeof(lock_para.cookie));
if (lock_para.lock == 0) {
if (owner_cookie == lock_para.cookie) {
owner_cookie = 0;
up(&lock);
PR("lock released, cookie: %s\n", cookie_msg);
} else
memcpy(owner_msg, &owner_cookie, sizeof(owner_cookie));
PR("release, cookie_mismatch:%s, owner:%s\n", cookie_msg,
owner_cookie == 0 ? "NULL" : owner_msg);
} else if (lock_para.lock == 1) {
#if 1
if (down_interruptible(&lock)) {
PR("interrupted\n");
return -ERESTARTSYS;
}
#else
down(&lock);
#endif
owner_cookie = lock_para.cookie;
PR("lock acquired, %s\n", cookie_msg);
} else if (lock_para.lock == 2) {
if (down_trylock(&lock) != 0) {
PR("try failed\n");
return -ERESTARTSYS;
} else {
PR("try success\n");
owner_cookie = lock_para.cookie;
}
}
return ret;
}
static long btlock_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
return 0;
}
static const struct file_operations btlock_fops = {
.owner = THIS_MODULE,
.open = btlock_open,
.release = btlock_release,
.write = btlock_write,
.unlocked_ioctl = btlock_unlocked_ioctl,
};
static struct miscdevice btlock_misc = {
.name = BTLOCK_NAME,
.minor = BTLOCK_MINOR,
.fops = &btlock_fops,
};
static int __init btlock_init(void)
{
int ret;
PR("init\n");
ret = misc_register(&btlock_misc);
if (ret != 0) {
PR("Error: failed to register Misc driver, ret = %d\n", ret);
return ret;
}
sema_init(&lock, 1);
return ret;
}
static void __exit btlock_exit(void)
{
PR("btlock_exit:\n");
misc_deregister(&btlock_misc);
}
module_init(btlock_init);
module_exit(btlock_exit);
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