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/*
* ADM5120_WDT 0.01: Infineon ADM5120 SoC watchdog driver
* Copyright (c) Ondrej Zajicek <santiago@crfreenet.org>, 2007
*
* based on
*
* RC32434_WDT 0.01: IDT Interprise 79RC32434 watchdog driver
*
* 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.
*
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/irq.h>
#include <asm/bootinfo.h>
#include <asm/mach-adm5120/adm5120_info.h>
#include <asm/mach-adm5120/adm5120_defs.h>
#include <asm/mach-adm5120/adm5120_switch.h>
#define DEFAULT_TIMEOUT 15 /* (secs) Default is 15 seconds */
#define MAX_TIMEOUT 327
/* Max is 327 seconds, counter is 15-bit integer, step is 10 ms */
#define NAME "adm5120_wdt"
#define VERSION "0.1"
static int expect_close;
static int access;
static unsigned int timeout = DEFAULT_TIMEOUT;
static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
MODULE_LICENSE("GPL");
static inline void wdt_set_timeout(void)
{
u32 val = (1 << 31) | (((timeout * 100) & 0x7FFF) << 16);
SW_WRITE_REG(SWITCH_REG_WDOG0, val);
}
/*
It looks like WDOG0-register-write don't modify counter,
but WDOG0-register-read resets counter.
*/
static inline void wdt_reset_counter(void)
{
SW_READ_REG(SWITCH_REG_WDOG0);
}
static inline void wdt_disable(void)
{
SW_WRITE_REG(SWITCH_REG_WDOG0, 0x7FFF0000);
}
static int wdt_open(struct inode *inode, struct file *file)
{
/* Allow only one person to hold it open */
if (access)
return -EBUSY;
if (nowayout)
__module_get(THIS_MODULE);
/* Activate timer */
wdt_reset_counter();
wdt_set_timeout();
printk(KERN_INFO NAME ": enabling watchdog timer\n");
access = 1;
return 0;
}
static int wdt_release(struct inode *inode, struct file *file)
{
/*
* Shut off the timer.
* Lock it in if it's a module and we set nowayout
*/
if (expect_close && (nowayout == 0)) {
wdt_disable();
printk(KERN_INFO NAME ": disabling watchdog timer\n");
module_put(THIS_MODULE);
} else
printk(KERN_CRIT NAME ": device closed unexpectedly. WDT will not stop!\n");
access = 0;
return 0;
}
static ssize_t wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
{
/* Refresh the timer. */
if (len) {
if (!nowayout) {
size_t i;
/* In case it was set long ago */
expect_close = 0;
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
expect_close = 1;
}
}
wdt_reset_counter();
return len;
}
return 0;
}
static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
int new_timeout;
static struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
.firmware_version = 0,
.identity = "ADM5120_WDT Watchdog",
};
switch (cmd) {
default:
return -ENOTTY;
case WDIOC_GETSUPPORT:
if (copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident)))
return -EFAULT;
return 0;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0, (int *)arg);
case WDIOC_KEEPALIVE:
wdt_reset_counter();
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_timeout, (int *)arg))
return -EFAULT;
if (new_timeout < 1)
return -EINVAL;
if (new_timeout > MAX_TIMEOUT)
return -EINVAL;
timeout = new_timeout;
wdt_set_timeout();
/* Fall */
case WDIOC_GETTIMEOUT:
return put_user(timeout, (int *)arg);
}
}
static const struct file_operations wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = wdt_write,
.unlocked_ioctl = wdt_ioctl,
.open = wdt_open,
.release = wdt_release,
};
static struct miscdevice wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &wdt_fops,
};
static char banner[] __initdata = KERN_INFO NAME ": Watchdog Timer version " VERSION "\n";
static int __init watchdog_init(void)
{
int ret;
ret = misc_register(&wdt_miscdev);
if (ret)
return ret;
wdt_disable();
printk(banner);
return 0;
}
static void __exit watchdog_exit(void)
{
misc_deregister(&wdt_miscdev);
}
module_init(watchdog_init);
module_exit(watchdog_exit);
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