/*
* Watchdog driver for Broadcom BCM47XX
*
* Copyright (C) 2008 Aleksandar Radovanovic <biblbroks@sezampro.rs>
* Copyright (C) 2009 Matthieu CASTET <castet.matthieu@free.fr>
*
* 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/bitops.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/reboot.h>
#include <linux/types.h>
#include <linux/uaccess.h>
#include <linux/watchdog.h>
#include <linux/timer.h>
#include <linux/jiffies.h>
#include <linux/ssb/ssb_embedded.h>
#include <asm/mach-bcm47xx/bcm47xx.h>
#define DRV_NAME "bcm47xx_wdt"
#define WDT_DEFAULT_TIME 30 /* seconds */
#define WDT_MAX_TIME 255 /* seconds */
static int wdt_time = WDT_DEFAULT_TIME;
static int nowayout = WATCHDOG_NOWAYOUT;
module_param(wdt_time, int, 0);
MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
__MODULE_STRING(WDT_DEFAULT_TIME) ")");
#ifdef CONFIG_WATCHDOG_NOWAYOUT
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
#endif
static unsigned long bcm47xx_wdt_busy;
static char expect_release;
static struct timer_list wdt_timer;
static atomic_t ticks;
static inline void bcm47xx_wdt_hw_start(void)
{
/* this is 2,5s on 100Mhz clock and 2s on 133 Mhz */
ssb_watchdog_timer_set(&ssb_bcm47xx, 0xfffffff);
}
static inline int bcm47xx_wdt_hw_stop(void)
{
return ssb_watchdog_timer_set(&ssb_bcm47xx, 0);
}
static void bcm47xx_timer_tick(unsigned long unused)
{
if (!atomic_dec_and_test(&ticks)) {
bcm47xx_wdt_hw_start();
mod_timer(&wdt_timer, jiffies + HZ);
} else {
printk(KERN_CRIT DRV_NAME "Watchdog will fire soon!!!\n");
}
}
static inline void bcm47xx_wdt_pet(void)
{
atomic_set(&ticks, wdt_time);
}
static void bcm47xx_wdt_start(void)
{
bcm47xx_wdt_pet();
bcm47xx_timer_tick(0);
}
static void bcm47xx_wdt_pause(void)
{
del_timer_sync(&wdt_timer);
bcm47xx_wdt_hw_stop();
}
static void bcm47xx_wdt_stop(void)
{
bcm47xx_wdt_pause();
}
static int bcm47xx_wdt_settimeout(int new_time)
{
if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
return -EINVAL;
wdt_time = new_time;
return 0;
}
static int bcm47xx_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &bcm47xx_wdt_busy))
return -EBUSY;
bcm47xx_wdt_start();
return nonseekable_open(inode, file);
}
static int bcm47xx_wdt_release(struct inode *inode, struct file *file)
{
if (expect_release == 42) {
bcm47xx_wdt_stop();
} else {
printk(KERN_CRIT DRV_NAME
": Unexpected close, not stopping watchdog!\n");
bcm47xx_wdt_start();
}
clear_bit(0, &bcm47xx_wdt_busy);
expect_release = 0;
return 0;
}
static ssize_t bcm47xx_wdt_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
if (len) {
if (!nowayout) {
size_t i;
expect_release = 0;
for (i = 0; i != len; i++) {
char c;
if (get_user(c, data + i))
return -EFAULT;
if (c == 'V')
expect_release = 42;
}
}
bcm47xx_wdt_pet();
}
return len;
}
static const struct watchdog_info bcm47xx_wdt_info = {
.identity = DRV_NAME,
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
};
static long bcm47xx_wdt_ioctl(struct file *file,
unsigned int cmd, unsigned long arg)
{
void __user *argp = (void __user *)arg;
int __user *p = argp;
int new_value, retval = -EINVAL;
switch (cmd) {
case WDIOC_GETSUPPORT:
return copy_to_user(argp, &bcm47xx_wdt_info,
sizeof(bcm47xx_wdt_info)) ? -EFAULT : 0;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0, p);
case WDIOC_SETOPTIONS:
if (get_user(new_value, p))
return -EFAULT;
if (new_value & WDIOS_DISABLECARD) {
bcm47xx_wdt_stop();
retval = 0;
}
if (new_value & WDIOS_ENABLECARD) {
bcm47xx_wdt_start();
retval = 0;
}
return retval;
case WDIOC_KEEPALIVE:
bcm47xx_wdt_pet();
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_value, p))
return -EFAULT;
if (bcm47xx_wdt_settimeout(new_value))
return -EINVAL;
bcm47xx_wdt_pet();
case WDIOC_GETTIMEOUT:
return put_user(wdt_time, p);
default:
return -ENOTTY;
}
}
static int bcm47xx_wdt_notify_sys(struct notifier_block *this,
unsigned long code, void *unused)
{
if (code == SYS_DOWN || code == SYS_HALT)
bcm47xx_wdt_stop();
return NOTIFY_DONE;
}
static const struct file_operations bcm47xx_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.unlocked_ioctl = bcm47xx_wdt_ioctl,
.open = bcm47xx_wdt_open,
.release = bcm47xx_wdt_release,
.write = bcm47xx_wdt_write,
};
static struct miscdevice bcm47xx_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &bcm47xx_wdt_fops,
};
static struct notifier_block bcm47xx_wdt_notifier = {
.notifier_call = bcm47xx_wdt_notify_sys,
};
static int __init bcm47xx_wdt_init(void)
{
int ret;
if (bcm47xx_wdt_hw_stop() < 0)
return -ENODEV;
setup_timer(&wdt_timer, bcm47xx_timer_tick, 0L);
if (bcm47xx_wdt_settimeout(wdt_time)) {
bcm47xx_wdt_settimeout(WDT_DEFAULT_TIME);
printk(KERN_INFO DRV_NAME ": "
"wdt_time value must be 0 < wdt_time < %d, using %d\n",
(WDT_MAX_TIME + 1), wdt_time);
}
ret = register_reboot_notifier(&bcm47xx_wdt_notifier);
if (ret)
return ret;
ret = misc_register(&bcm47xx_wdt_miscdev);
if (ret) {
unregister_reboot_notifier(&bcm47xx_wdt_notifier);
return ret;
}
printk(KERN_INFO "BCM47xx Watchdog Timer enabled (%d seconds%s)\n",
wdt_time, nowayout ? ", nowayout" : "");
return 0;
}
static void __exit bcm47xx_wdt_exit(void)
{
if (!nowayout)
bcm47xx_wdt_stop();
misc_deregister(&bcm47xx_wdt_miscdev);
unregister_reboot_notifier(&bcm47xx_wdt_notifier);
}
module_init(bcm47xx_wdt_init);
module_exit(bcm47xx_wdt_exit);
MODULE_AUTHOR("Aleksandar Radovanovic");
MODULE_DESCRIPTION("Watchdog driver for Broadcom BCM47xx");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
