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/*
* Watchdog driver for the SA11x0/PXA2xx
*
* (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
* Based on SoftDog driver by Alan Cox <alan@redhat.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Neither Oleg Drokin nor iXcelerator.com admit liability nor provide
* warranty for any of this software. This material is provided
* "AS-IS" and at no charge.
*
* (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
*
* 27/11/2000 Initial release
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#ifdef CONFIG_ARCH_PXA
#include <asm/arch/pxa-regs.h>
#endif
#include <asm/hardware.h>
#include <asm/bitops.h>
#include <asm/uaccess.h>
#define OSCR_FREQ CLOCK_TICK_RATE
#define SA1100_CLOSE_MAGIC (0x5afc4453)
static unsigned long sa1100wdt_users;
static int expect_close;
static int pre_margin;
static int boot_status;
static int nowayout = WATCHDOG_NOWAYOUT;
/*
* Allow only one person to hold it open
*/
static int sa1100dog_open(struct inode *inode, struct file *file)
{
nonseekable_open(inode, file);
if (test_and_set_bit(1,&sa1100wdt_users))
return -EBUSY;
/* Activate SA1100 Watchdog timer */
OSMR3 = OSCR + pre_margin;
OSSR = OSSR_M3;
OWER = OWER_WME;
OIER |= OIER_E3;
return 0;
}
/*
* Shut off the timer.
* Lock it in if it's a module and we defined ...NOWAYOUT
* Oddly, the watchdog can only be enabled, but we can turn off
* the interrupt, which appears to prevent the watchdog timing out.
*/
static int sa1100dog_release(struct inode *inode, struct file *file)
{
OSMR3 = OSCR + pre_margin;
if (expect_close == SA1100_CLOSE_MAGIC) {
OIER &= ~OIER_E3;
} else {
printk(KERN_CRIT "WATCHDOG: WDT device closed unexpectedly. WDT will not stop!\n");
}
clear_bit(1, &sa1100wdt_users);
expect_close = 0;
return 0;
}
static ssize_t sa1100dog_write(struct file *file, const char *data, size_t len, loff_t *ppos)
{
if (len) {
if (!nowayout) {
size_t i;
expect_close = 0;
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
expect_close = SA1100_CLOSE_MAGIC;
}
}
/* Refresh OSMR3 timer. */
OSMR3 = OSCR + pre_margin;
}
return len;
}
static struct watchdog_info ident = {
.options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
.identity = "SA1100 Watchdog",
};
static int sa1100dog_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
int ret = -ENOIOCTLCMD;
int time;
switch (cmd) {
case WDIOC_GETSUPPORT:
ret = copy_to_user((struct watchdog_info *)arg, &ident,
sizeof(ident)) ? -EFAULT : 0;
break;
case WDIOC_GETSTATUS:
ret = put_user(0, (int *)arg);
break;
case WDIOC_GETBOOTSTATUS:
ret = put_user(boot_status, (int *)arg);
break;
case WDIOC_SETTIMEOUT:
ret = get_user(time, (int *)arg);
if (ret)
break;
if (time <= 0 || time > 255) {
ret = -EINVAL;
break;
}
pre_margin = OSCR_FREQ * time;
OSMR3 = OSCR + pre_margin;
/*fall through*/
case WDIOC_GETTIMEOUT:
ret = put_user(pre_margin / OSCR_FREQ, (int *)arg);
break;
case WDIOC_KEEPALIVE:
OSMR3 = OSCR + pre_margin;
ret = 0;
break;
}
return ret;
}
static struct file_operations sa1100dog_fops =
{
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = sa1100dog_write,
.ioctl = sa1100dog_ioctl,
.open = sa1100dog_open,
.release = sa1100dog_release,
};
static struct miscdevice sa1100dog_miscdev =
{
.minor = WATCHDOG_MINOR,
.name = "SA1100/PXA2xx watchdog",
.fops = &sa1100dog_fops,
};
static int margin __initdata = 60; /* (secs) Default is 1 minute */
static int __init sa1100dog_init(void)
{
int ret;
/*
* Read the reset status, and save it for later. If
* we suspend, RCSR will be cleared, and the watchdog
* reset reason will be lost.
*/
boot_status = (RCSR & RCSR_WDR) ? WDIOF_CARDRESET : 0;
pre_margin = OSCR_FREQ * margin;
ret = misc_register(&sa1100dog_miscdev);
if (ret == 0)
printk("SA1100/PXA2xx Watchdog Timer: timer margin %d sec\n",
margin);
return ret;
}
static void __exit sa1100dog_exit(void)
{
misc_deregister(&sa1100dog_miscdev);
}
module_init(sa1100dog_init);
module_exit(sa1100dog_exit);
MODULE_AUTHOR("Oleg Drokin <green@crimea.edu>");
MODULE_DESCRIPTION("SA1100/PXA2xx Watchdog");
module_param(margin, int, 0);
MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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