#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/uaccess.h>
#define S3C_VA_WATCHDOG (0)
#include <plat/regs-watchdog.h>
#define PFX "s3c2410-wdt: "
#define CONFIG_S3C2410_WATCHDOG_ATBOOT (1)
#define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME (30)
static int nowayout = WATCHDOG_NOWAYOUT;
static int tmr_margin = CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME;
static int tmr_atboot = CONFIG_S3C2410_WATCHDOG_ATBOOT;
module_param(tmr_margin,
int, 0); module_param(tmr_atboot,
int, 0); module_param(nowayout,
int, 0); module_param(soft_noboot, int, 0);
module_param(debug,
int, 0); MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. default="
__MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")");
MODULE_PARM_DESC(tmr_atboot,
"Watchdog is started at boot time if set to 1, default="
__MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT));
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to reboot (default depends on ONLY_TESTING)");
MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug, (default 0)");
typedef enum close_state {
CLOSE_STATE_ALLOW = 0x4021
static unsigned long open_lock;
static struct device
*wdt_dev; static struct resource *wdt_mem;
static struct resource *wdt_irq;
static struct clk *wdt_clock;
static void __iomem *wdt_base;
static unsigned int wdt_count;
static close_state_t allow_close;
static DEFINE_SPINLOCK(wdt_lock);
#define DBG(msg...) do { \
static void s3c2410wdt_keepalive(void)
writel(wdt_count, wdt_base + S3C2410_WTCNT);
static void __s3c2410wdt_stop(void)
wtcon = readl(wdt_base + S3C2410_WTCON);
wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN);
writel(wtcon, wdt_base + S3C2410_WTCON);
static void s3c2410wdt_stop(void)
static void s3c2410wdt_start(void)
wtcon = readl(wdt_base + S3C2410_WTCON);
wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128;
wtcon |= S3C2410_WTCON_INTEN;
wtcon &= ~S3C2410_WTCON_RSTEN;
wtcon &= ~S3C2410_WTCON_INTEN;
wtcon |= S3C2410_WTCON_RSTEN;
DBG("%s: wdt_count=0xx, wtcon=lx\n",
__func__, wdt_count, wtcon); writel(wdt_count, wdt_base + S3C2410_WTDAT);
writel(wdt_count, wdt_base + S3C2410_WTCNT);
writel(wtcon, wdt_base + S3C2410_WTCON);
static int s3c2410wdt_set_heartbeat(int timeout)
unsigned int freq = clk_get_rate(wdt_clock);
unsigned int divisor = 1;
DBG("%s: count=%d, timeout=%d, freq=%d\n",
__func__, count, timeout, freq); for (divisor = 1; divisor <= 0x100; divisor++) {
if ((count / divisor) < 0x10000)
if ((count / divisor) >= 0x10000) {
dev_err(wdt_dev, "timeout %d too big\n", timeout);
DBG("%s: timeout=%d, divisor=%d, count=%d (x)\n",
__func__, timeout, divisor, count, count/divisor); wtcon = readl(wdt_base + S3C2410_WTCON);
wtcon &= ~S3C2410_WTCON_PRESCALE_MASK;
wtcon |= S3C2410_WTCON_PRESCALE(divisor-1);
writel(count, wdt_base + S3C2410_WTDAT);
writel(wtcon, wdt_base + S3C2410_WTCON);
static int s3c2410wdt_open(struct inode *inode, struct file *file)
if (test_and_set_bit(0, &open_lock))
__module_get(THIS_MODULE);
allow_close = CLOSE_STATE_NOT;
return nonseekable_open(inode, file);
static int s3c2410wdt_release(struct inode *inode, struct file *file)
if (allow_close == CLOSE_STATE_ALLOW)
dev_err(wdt_dev, "Unexpected close, not stopping watchdog\n");
allow_close = CLOSE_STATE_NOT;
clear_bit(0, &open_lock);
static ssize_t s3c2410wdt_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
allow_close = CLOSE_STATE_NOT;
for (i = 0; i != len; i++) {
if (get_user(c, data + i))
allow_close = CLOSE_STATE_ALLOW;
#define OPTIONS WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE
static const struct watchdog_info s3c2410_wdt_ident = {
.identity
= "S3C2410 Watchdog", static long s3c2410wdt_ioctl(struct file *file, unsigned int cmd,
void __user *argp = (void __user *)arg;
return copy_to_user(argp, &s3c2410_wdt_ident,
sizeof(s3c2410_wdt_ident)) ? -EFAULT : 0;
case WDIOC_GETBOOTSTATUS:
if (get_user(new_margin, p))
if (s3c2410wdt_set_heartbeat(new_margin))
return put_user(tmr_margin, p);
return put_user(tmr_margin, p);
static const struct file_operations s3c2410wdt_fops = {
.write = s3c2410wdt_write,
.unlocked_ioctl = s3c2410wdt_ioctl,
.release = s3c2410wdt_release,
static struct miscdevice s3c2410wdt_miscdev = {
.fops = &s3c2410wdt_fops,
static irqreturn_t s3c2410wdt_irq(int irqno, void *param)
dev_info(wdt_dev, "watchdog timer expired (irq)\n");
static int s3c2410wdt_probe(struct platform_device *pdev)
DBG("%s: probe=%p\n", __func__, pdev);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
dev_err(dev, "no memory resource specified\n");
size = (res->end - res->start) + 1;
wdt_mem = request_mem_region(res->start, size, pdev->name);
dev_err(dev, "failed to get memory region\n");
wdt_base = ioremap(res->start, size);
dev_err(dev, "failed to ioremap() region\n");
DBG("probe: mapped wdt_base=%p\n", wdt_base);
wdt_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
dev_err(dev, "no irq resource specified\n");
ret = request_irq(wdt_irq->start, s3c2410wdt_irq, 0, pdev->name, pdev);
dev_err(dev, "failed to install irq (%d)\n", ret);
wdt_clock = clk_get(&pdev->dev, "watchdog");
dev_err(dev, "failed to find watchdog clock source\n");
ret = PTR_ERR(wdt_clock);
if (s3c2410wdt_set_heartbeat(tmr_margin)) {
started = s3c2410wdt_set_heartbeat(
CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
"tmr_margin value out of range, default %d used\n", CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME); dev_info(dev, "default timer value is out of range, cannot start\n");
ret = misc_register(&s3c2410wdt_miscdev);
dev_err(dev, "cannot register miscdev on minor=%d (%d)\n",
if (tmr_atboot && started == 0) {
dev_info(dev, "starting watchdog timer\n");
} else if (!tmr_atboot) {
wtcon = readl(wdt_base + S3C2410_WTCON);
dev_info(dev, "watchdog %sactive, reset %sabled, irq %sabled\n",
(wtcon & S3C2410_WTCON_ENABLE) ?
"" : "in", (wtcon & S3C2410_WTCON_RSTEN) ? "" : "dis",
(wtcon & S3C2410_WTCON_INTEN) ? "" : "en");
free_irq(wdt_irq->start, pdev);
release_resource(wdt_mem);
static int s3c2410wdt_remove(struct platform_device *dev)
release_resource(wdt_mem);
free_irq(wdt_irq->start, dev);
misc_deregister(&s3c2410wdt_miscdev);
static void s3c2410wdt_shutdown(struct platform_device *dev)
static unsigned long wtcon_save;
static unsigned long wtdat_save;
static int s3c2410wdt_suspend(struct platform_device *dev, pm_message_t state)
wtcon_save = readl(wdt_base + S3C2410_WTCON);
wtdat_save = readl(wdt_base + S3C2410_WTDAT);
static int s3c2410wdt_resume(struct platform_device *dev)
writel(wtdat_save, wdt_base + S3C2410_WTDAT);
writel(wtdat_save, wdt_base + S3C2410_WTCNT);
writel(wtcon_save, wdt_base + S3C2410_WTCON);
printk(KERN_INFO PFX "watchdog %sabled\n",
(wtcon_save & S3C2410_WTCON_ENABLE) ? "en" : "dis"); #define s3c2410wdt_suspend NULL
#define s3c2410wdt_resume
NULL static struct platform_driver s3c2410wdt_driver = {
.probe = s3c2410wdt_probe,
.remove = s3c2410wdt_remove,
.shutdown = s3c2410wdt_shutdown,
.suspend = s3c2410wdt_suspend,
.resume = s3c2410wdt_resume,
static char banner[] __initdata =
KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n";
static int __init watchdog_init(void)
return platform_driver_register(&s3c2410wdt_driver);
static void __exit watchdog_exit(void)
platform_driver_unregister(&s3c2410wdt_driver);
module_init(watchdog_init);
module_exit(watchdog_exit);
MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, "
"Dimitry Andric <dimitry.andric@tomtom.com>"); MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
MODULE_ALIAS("platform:s3c2410-wdt");