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/*
* drivers/watchdog/orion5x_wdt.c
*
* Watchdog driver for Orion5x processors
*
* Author: Sylver Bruneau <sylver.bruneau@googlemail.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#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>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/spinlock.h>
/*
* Watchdog timer block registers.
*/
#define TIMER_CTRL (TIMER_VIRT_BASE + 0x0000)
#define WDT_EN 0x0010
#define WDT_VAL (TIMER_VIRT_BASE + 0x0024)
#define ORION5X_TCLK 166666667
#define WDT_MAX_DURATION (0xffffffff / ORION5X_TCLK)
#define WDT_IN_USE 0
#define WDT_OK_TO_CLOSE 1
static int nowayout = WATCHDOG_NOWAYOUT;
static int heartbeat = WDT_MAX_DURATION; /* (seconds) */
static unsigned long wdt_status;
static spinlock_t wdt_lock;
static void wdt_enable(void)
{
u32 reg;
spin_lock(&wdt_lock);
/* Set watchdog duration */
writel(ORION5X_TCLK * heartbeat, WDT_VAL);
/* Clear watchdog timer interrupt */
reg = readl(BRIDGE_CAUSE);
reg &= ~WDT_INT_REQ;
writel(reg, BRIDGE_CAUSE);
/* Enable watchdog timer */
reg = readl(TIMER_CTRL);
reg |= WDT_EN;
writel(reg, TIMER_CTRL);
/* Enable reset on watchdog */
reg = readl(CPU_RESET_MASK);
reg |= WDT_RESET;
writel(reg, CPU_RESET_MASK);
spin_unlock(&wdt_lock);
}
static void wdt_disable(void)
{
u32 reg;
spin_lock(&wdt_lock);
/* Disable reset on watchdog */
reg = readl(CPU_RESET_MASK);
reg &= ~WDT_RESET;
writel(reg, CPU_RESET_MASK);
/* Disable watchdog timer */
reg = readl(TIMER_CTRL);
reg &= ~WDT_EN;
writel(reg, TIMER_CTRL);
spin_unlock(&wdt_lock);
}
static int orion5x_wdt_get_timeleft(int *time_left)
{
spin_lock(&wdt_lock);
*time_left = readl(WDT_VAL) / ORION5X_TCLK;
spin_unlock(&wdt_lock);
return 0;
}
static int orion5x_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(WDT_IN_USE, &wdt_status))
return -EBUSY;
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
wdt_enable();
return nonseekable_open(inode, file);
}
static ssize_t orion5x_wdt_write(struct file *file, const char *data,
size_t len, loff_t *ppos)
{
if (len) {
if (!nowayout) {
size_t i;
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
set_bit(WDT_OK_TO_CLOSE, &wdt_status);
}
}
wdt_enable();
}
return len;
}
static struct watchdog_info ident = {
.options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING,
.identity = "Orion5x Watchdog",
};
static long orion5x_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int ret = -ENOTTY;
int time;
switch (cmd) {
case WDIOC_GETSUPPORT:
ret = copy_to_user((struct watchdog_info *)arg, &ident,
sizeof(ident)) ? -EFAULT : 0;
break;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
ret = put_user(0, (int *)arg);
break;
case WDIOC_KEEPALIVE:
wdt_enable();
ret = 0;
break;
case WDIOC_SETTIMEOUT:
ret = get_user(time, (int *)arg);
if (ret)
break;
if (time <= 0 || time > WDT_MAX_DURATION) {
ret = -EINVAL;
break;
}
heartbeat = time;
wdt_enable();
/* Fall through */
case WDIOC_GETTIMEOUT:
ret = put_user(heartbeat, (int *)arg);
break;
case WDIOC_GETTIMELEFT:
if (orion5x_wdt_get_timeleft(&time)) {
ret = -EINVAL;
break;
}
ret = put_user(time, (int *)arg);
break;
}
return ret;
}
static int orion5x_wdt_release(struct inode *inode, struct file *file)
{
if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
wdt_disable();
else
printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
"timer will not stop\n");
clear_bit(WDT_IN_USE, &wdt_status);
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
return 0;
}
static const struct file_operations orion5x_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = orion5x_wdt_write,
.unlocked_ioctl = orion5x_wdt_ioctl,
.open = orion5x_wdt_open,
.release = orion5x_wdt_release,
};
static struct miscdevice orion5x_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &orion5x_wdt_fops,
};
static int __init orion5x_wdt_init(void)
{
int ret;
spin_lock_init(&wdt_lock);
ret = misc_register(&orion5x_wdt_miscdev);
if (ret == 0)
printk("Orion5x Watchdog Timer: heartbeat %d sec\n",
heartbeat);
return ret;
}
static void __exit orion5x_wdt_exit(void)
{
misc_deregister(&orion5x_wdt_miscdev);
}
module_init(orion5x_wdt_init);
module_exit(orion5x_wdt_exit);
MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
MODULE_DESCRIPTION("Orion5x Processor Watchdog");
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default is "
__MODULE_STRING(WDT_MAX_DURATION) ")");
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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