/*
* Watchdog driver for Freescale STMP37XX/STMP378X
*
* Author: Vitaly Wool <vital@embeddedalley.com>
*
* Copyright 2008 Freescale Semiconductor, Inc. All Rights Reserved.
* Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <mach/platform.h>
#include <mach/regs-rtc.h>
#define DEFAULT_HEARTBEAT 19
#define MAX_HEARTBEAT (0x10000000 >> 6)
/* missing bitmask in headers */
#define BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER 0x80000000
#define WDT_IN_USE 0
#define WDT_OK_TO_CLOSE 1
#define WDOG_COUNTER_RATE 1000 /* 1 kHz clock */
static DEFINE_SPINLOCK(stmp3xxx_wdt_io_lock);
static unsigned long wdt_status;
static const int nowayout = WATCHDOG_NOWAYOUT;
static int heartbeat = DEFAULT_HEARTBEAT;
static unsigned long boot_status;
static void wdt_enable(u32 value)
{
spin_lock(&stmp3xxx_wdt_io_lock);
__raw_writel(value, REGS_RTC_BASE + HW_RTC_WATCHDOG);
stmp3xxx_setl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL);
stmp3xxx_setl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
REGS_RTC_BASE + HW_RTC_PERSISTENT1);
spin_unlock(&stmp3xxx_wdt_io_lock);
}
static void wdt_disable(void)
{
spin_lock(&stmp3xxx_wdt_io_lock);
stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
REGS_RTC_BASE + HW_RTC_PERSISTENT1);
stmp3xxx_clearl(BM_RTC_CTRL_WATCHDOGEN, REGS_RTC_BASE + HW_RTC_CTRL);
spin_unlock(&stmp3xxx_wdt_io_lock);
}
static void wdt_ping(void)
{
wdt_enable(heartbeat * WDOG_COUNTER_RATE);
}
static int stmp3xxx_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_ping();
return nonseekable_open(inode, file);
}
static ssize_t stmp3xxx_wdt_write(struct file *file, const char __user *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_ping();
}
return len;
}
static const struct watchdog_info ident = {
.options = WDIOF_CARDRESET |
WDIOF_MAGICCLOSE |
WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING,
.identity = "STMP3XXX Watchdog",
};
static long stmp3xxx_wdt_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
void __user *argp = (void __user *)arg;
int __user *p = argp;
int new_heartbeat, opts;
int ret = -ENOTTY;
switch (cmd) {
case WDIOC_GETSUPPORT:
ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
break;
case WDIOC_GETSTATUS:
ret = put_user(0, p);
break;
case WDIOC_GETBOOTSTATUS:
ret = put_user(boot_status, p);
break;
case WDIOC_SETOPTIONS:
if (get_user(opts, p)) {
ret = -EFAULT;
break;
}
if (opts & WDIOS_DISABLECARD)
wdt_disable();
else if (opts & WDIOS_ENABLECARD)
wdt_ping();
else {
pr_debug("%s: unknown option 0x%x\n", __func__, opts);
ret = -EINVAL;
break;
}
ret = 0;
break;
case WDIOC_KEEPALIVE:
wdt_ping();
ret = 0;
break;
case WDIOC_SETTIMEOUT:
if (get_user(new_heartbeat, p)) {
ret = -EFAULT;
break;
}
if (new_heartbeat <= 0 || new_heartbeat > MAX_HEARTBEAT) {
ret = -EINVAL;
break;
}
heartbeat = new_heartbeat;
wdt_ping();
/* Fall through */
case WDIOC_GETTIMEOUT:
ret = put_user(heartbeat, p);
break;
}
return ret;
}
static int stmp3xxx_wdt_release(struct inode *inode, struct file *file)
{
int ret = 0;
if (!nowayout) {
if (!test_bit(WDT_OK_TO_CLOSE, &wdt_status)) {
wdt_ping();
pr_debug("%s: Device closed unexpectedly\n", __func__);
ret = -EINVAL;
} else {
wdt_disable();
clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
}
}
clear_bit(WDT_IN_USE, &wdt_status);
return ret;
}
static const struct file_operations stmp3xxx_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = stmp3xxx_wdt_write,
.unlocked_ioctl = stmp3xxx_wdt_ioctl,
.open = stmp3xxx_wdt_open,
.release = stmp3xxx_wdt_release,
};
static struct miscdevice stmp3xxx_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &stmp3xxx_wdt_fops,
};
static int __devinit stmp3xxx_wdt_probe(struct platform_device *pdev)
{
int ret = 0;
if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
heartbeat = DEFAULT_HEARTBEAT;
boot_status = __raw_readl(REGS_RTC_BASE + HW_RTC_PERSISTENT1) &
BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER;
boot_status = !!boot_status;
stmp3xxx_clearl(BV_RTC_PERSISTENT1_GENERAL__RTC_FORCE_UPDATER,
REGS_RTC_BASE + HW_RTC_PERSISTENT1);
wdt_disable(); /* disable for now */
ret = misc_register(&stmp3xxx_wdt_miscdev);
if (ret < 0) {
dev_err(&pdev->dev, "cannot register misc device\n");
return ret;
}
printk(KERN_INFO "stmp3xxx watchdog: initialized, heartbeat %d sec\n",
heartbeat);
return ret;
}
static int __devexit stmp3xxx_wdt_remove(struct platform_device *pdev)
{
misc_deregister(&stmp3xxx_wdt_miscdev);
return 0;
}
#ifdef CONFIG_PM
static int wdt_suspended;
static u32 wdt_saved_time;
static int stmp3xxx_wdt_suspend(struct platform_device *pdev,
pm_message_t state)
{
if (__raw_readl(REGS_RTC_BASE + HW_RTC_CTRL) &
BM_RTC_CTRL_WATCHDOGEN) {
wdt_suspended = 1;
wdt_saved_time = __raw_readl(REGS_RTC_BASE + HW_RTC_WATCHDOG);
wdt_disable();
}
return 0;
}
static int stmp3xxx_wdt_resume(struct platform_device *pdev)
{
if (wdt_suspended) {
wdt_enable(wdt_saved_time);
wdt_suspended = 0;
}
return 0;
}
#else
#define stmp3xxx_wdt_suspend NULL
#define stmp3xxx_wdt_resume NULL
#endif
static struct platform_driver platform_wdt_driver = {
.driver = {
.name = "stmp3xxx_wdt",
},
.probe = stmp3xxx_wdt_probe,
.remove = __devexit_p(stmp3xxx_wdt_remove),
.suspend = stmp3xxx_wdt_suspend,
.resume = stmp3xxx_wdt_resume,
};
module_platform_driver(platform_wdt_driver);
MODULE_DESCRIPTION("STMP3XXX Watchdog Driver");
MODULE_LICENSE("GPL");
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat,
"Watchdog heartbeat period in seconds from 1 to "
__MODULE_STRING(MAX_HEARTBEAT) ", default "
__MODULE_STRING(DEFAULT_HEARTBEAT));
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
