/*
* Watchdog driver for the mpcore watchdog timer
*
* (c) Copyright 2004 ARM Limited
*
* Based on the SoftDog driver:
* (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
* http://www.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 Alan Cox nor CymruNet Ltd. admit liability nor provide
* warranty for any of this software. This material is provided
* "AS-IS" and at no charge.
*
* (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
*
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/fs.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <asm/hardware/arm_twd.h>
#include <asm/uaccess.h>
struct mpcore_wdt {
unsigned long timer_alive;
struct device *dev;
void __iomem *base;
int irq;
unsigned int perturb;
char expect_close;
};
static struct platform_device *mpcore_wdt_dev;
extern unsigned int mpcore_timer_rate;
#define TIMER_MARGIN 60
static int mpcore_margin = TIMER_MARGIN;
module_param(mpcore_margin, int, 0);
MODULE_PARM_DESC(mpcore_margin, "MPcore timer margin in seconds. (0<mpcore_margin<65536, default=" __MODULE_STRING(TIMER_MARGIN) ")");
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) ")");
#define ONLY_TESTING 0
static int mpcore_noboot = ONLY_TESTING;
module_param(mpcore_noboot, int, 0);
MODULE_PARM_DESC(mpcore_noboot, "MPcore watchdog action, set to 1 to ignore reboots, 0 to reboot (default=" __MODULE_STRING(ONLY_TESTING) ")");
/*
* This is the interrupt handler. Note that we only use this
* in testing mode, so don't actually do a reboot here.
*/
static irqreturn_t mpcore_wdt_fire(int irq, void *arg)
{
struct mpcore_wdt *wdt = arg;
/* Check it really was our interrupt */
if (readl(wdt->base + TWD_WDOG_INTSTAT)) {
dev_printk(KERN_CRIT, wdt->dev, "Triggered - Reboot ignored.\n");
/* Clear the interrupt on the watchdog */
writel(1, wdt->base + TWD_WDOG_INTSTAT);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
/*
* mpcore_wdt_keepalive - reload the timer
*
* Note that the spec says a DIFFERENT value must be written to the reload
* register each time. The "perturb" variable deals with this by adding 1
* to the count every other time the function is called.
*/
static void mpcore_wdt_keepalive(struct mpcore_wdt *wdt)
{
unsigned int count;
/* Assume prescale is set to 256 */
count = (mpcore_timer_rate / 256) * mpcore_margin;
/* Reload the counter */
writel(count + wdt->perturb, wdt->base + TWD_WDOG_LOAD);
wdt->perturb = wdt->perturb ? 0 : 1;
}
static void mpcore_wdt_stop(struct mpcore_wdt *wdt)
{
writel(0x12345678, wdt->base + TWD_WDOG_DISABLE);
writel(0x87654321, wdt->base + TWD_WDOG_DISABLE);
writel(0x0, wdt->base + TWD_WDOG_CONTROL);
}
static void mpcore_wdt_start(struct mpcore_wdt *wdt)
{
dev_printk(KERN_INFO, wdt->dev, "enabling watchdog.\n");
/* This loads the count register but does NOT start the count yet */
mpcore_wdt_keepalive(wdt);
if (mpcore_noboot) {
/* Enable watchdog - prescale=256, watchdog mode=0, enable=1 */
writel(0x0000FF01, wdt->base + TWD_WDOG_CONTROL);
} else {
/* Enable watchdog - prescale=256, watchdog mode=1, enable=1 */
writel(0x0000FF09, wdt->base + TWD_WDOG_CONTROL);
}
}
static int mpcore_wdt_set_heartbeat(int t)
{
if (t < 0x0001 || t > 0xFFFF)
return -EINVAL;
mpcore_margin = t;
return 0;
}
/*
* /dev/watchdog handling
*/
static int mpcore_wdt_open(struct inode *inode, struct file *file)
{
struct mpcore_wdt *wdt = platform_get_drvdata(mpcore_wdt_dev);
if (test_and_set_bit(0, &wdt->timer_alive))
return -EBUSY;
if (nowayout)
__module_get(THIS_MODULE);
file->private_data = wdt;
/*
* Activate timer
*/
mpcore_wdt_start(wdt);
return nonseekable_open(inode, file);
}
static int mpcore_wdt_release(struct inode *inode, struct file *file)
{
struct mpcore_wdt *wdt = file->private_data;
/*
* Shut off the timer.
* Lock it in if it's a module and we set nowayout
*/
if (wdt->expect_close == 42) {
mpcore_wdt_stop(wdt);
} else {
dev_printk(KERN_CRIT, wdt->dev, "unexpected close, not stopping watchdog!\n");
mpcore_wdt_keepalive(wdt);
}
clear_bit(0, &wdt->timer_alive);
wdt->expect_close = 0;
return 0;
}
static ssize_t mpcore_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
{
struct mpcore_wdt *wdt = file->private_data;
/*
* Refresh the timer.
*/
if (len) {
if (!nowayout) {
size_t i;
/* In case it was set long ago */
wdt->expect_close = 0;
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
wdt->expect_close = 42;
}
}
mpcore_wdt_keepalive(wdt);
}
return len;
}
static struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
.identity = "MPcore Watchdog",
};
static int mpcore_wdt_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct mpcore_wdt *wdt = file->private_data;
int ret;
union {
struct watchdog_info ident;
int i;
} uarg;
if (_IOC_DIR(cmd) && _IOC_SIZE(cmd) > sizeof(uarg))
return -ENOTTY;
if (_IOC_DIR(cmd) & _IOC_WRITE) {
ret = copy_from_user(&uarg, (void __user *)arg, _IOC_SIZE(cmd));
if (ret)
return -EFAULT;
}
switch (cmd) {
case WDIOC_GETSUPPORT:
uarg.ident = ident;
ret = 0;
break;
case WDIOC_SETOPTIONS:
ret = -EINVAL;
if (uarg.i & WDIOS_DISABLECARD) {
mpcore_wdt_stop(wdt);
ret = 0;
}
if (uarg.i & WDIOS_ENABLECARD) {
mpcore_wdt_start(wdt);
ret = 0;
}
break;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
uarg.i = 0;
ret = 0;
break;
case WDIOC_KEEPALIVE:
mpcore_wdt_keepalive(wdt);
ret = 0;
break;
case WDIOC_SETTIMEOUT:
ret = mpcore_wdt_set_heartbeat(uarg.i);
if (ret)
break;
mpcore_wdt_keepalive(wdt);
/* Fall */
case WDIOC_GETTIMEOUT:
uarg.i = mpcore_margin;
ret = 0;
break;
default:
return -ENOTTY;
}
if (ret == 0 && _IOC_DIR(cmd) & _IOC_READ) {
ret = copy_to_user((void __user *)arg, &uarg, _IOC_SIZE(cmd));
if (ret)
ret = -EFAULT;
}
return ret;
}
/*
* System shutdown handler. Turn off the watchdog if we're
* restarting or halting the system.
*/
static void mpcore_wdt_shutdown(struct platform_device *dev)
{
struct mpcore_wdt *wdt = platform_get_drvdata(dev);
if (system_state == SYSTEM_RESTART || system_state == SYSTEM_HALT)
mpcore_wdt_stop(wdt);
}
/*
* Kernel Interfaces
*/
static const struct file_operations mpcore_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = mpcore_wdt_write,
.ioctl = mpcore_wdt_ioctl,
.open = mpcore_wdt_open,
.release = mpcore_wdt_release,
};
static struct miscdevice mpcore_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &mpcore_wdt_fops,
};
static int __devinit mpcore_wdt_probe(struct platform_device *dev)
{
struct mpcore_wdt *wdt;
struct resource *res;
int ret;
/* We only accept one device, and it must have an id of -1 */
if (dev->id != -1)
return -ENODEV;
res = platform_get_resource(dev, IORESOURCE_MEM, 0);
if (!res) {
ret = -ENODEV;
goto err_out;
}
wdt = kzalloc(sizeof(struct mpcore_wdt), GFP_KERNEL);
if (!wdt) {
ret = -ENOMEM;
goto err_out;
}
wdt->dev = &dev->dev;
wdt->irq = platform_get_irq(dev, 0);
if (wdt->irq < 0) {
ret = -ENXIO;
goto err_free;
}
wdt->base = ioremap(res->start, res->end - res->start + 1);
if (!wdt->base) {
ret = -ENOMEM;
goto err_free;
}
mpcore_wdt_miscdev.parent = &dev->dev;
ret = misc_register(&mpcore_wdt_miscdev);
if (ret) {
dev_printk(KERN_ERR, _dev, "cannot register miscdev on minor=%d (err=%d)\n",
WATCHDOG_MINOR, ret);
goto err_misc;
}
ret = request_irq(wdt->irq, mpcore_wdt_fire, IRQF_DISABLED, "mpcore_wdt", wdt);
if (ret) {
dev_printk(KERN_ERR, _dev, "cannot register IRQ%d for watchdog\n", wdt->irq);
goto err_irq;
}
mpcore_wdt_stop(wdt);
platform_set_drvdata(&dev->dev, wdt);
mpcore_wdt_dev = dev;
return 0;
err_irq:
misc_deregister(&mpcore_wdt_miscdev);
err_misc:
iounmap(wdt->base);
err_free:
kfree(wdt);
err_out:
return ret;
}
static int __devexit mpcore_wdt_remove(struct platform_device *dev)
{
struct mpcore_wdt *wdt = platform_get_drvdata(dev);
platform_set_drvdata(dev, NULL);
misc_deregister(&mpcore_wdt_miscdev);
mpcore_wdt_dev = NULL;
free_irq(wdt->irq, wdt);
iounmap(wdt->base);
kfree(wdt);
return 0;
}
static struct platform_driver mpcore_wdt_driver = {
.probe = mpcore_wdt_probe,
.remove = __devexit_p(mpcore_wdt_remove),
.shutdown = mpcore_wdt_shutdown,
.driver = {
.owner = THIS_MODULE,
.name = "mpcore_wdt",
},
};
static char banner[] __initdata = KERN_INFO "MPcore Watchdog Timer: 0.1. mpcore_noboot=%d mpcore_margin=%d sec (nowayout= %d)\n";
static int __init mpcore_wdt_init(void)
{
/*
* Check that the margin value is within it's range;
* if not reset to the default
*/
if (mpcore_wdt_set_heartbeat(mpcore_margin)) {
mpcore_wdt_set_heartbeat(TIMER_MARGIN);
printk(KERN_INFO "mpcore_margin value must be 0<mpcore_margin<65536, using %d\n",
TIMER_MARGIN);
}
printk(banner, mpcore_noboot, mpcore_margin, nowayout);
return platform_driver_register(&mpcore_wdt_driver);
}
static void __exit mpcore_wdt_exit(void)
{
platform_driver_unregister(&mpcore_wdt_driver);
}
module_init(mpcore_wdt_init);
module_exit(mpcore_wdt_exit);
MODULE_AUTHOR("ARM Limited");
MODULE_DESCRIPTION("MPcore Watchdog Device Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
