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[PATCH] cirrus ep93xx watchdog driver
Add a driver for the on-chip watchdog on the cirrus ep93xx series of ARM CPUs. Signed-off-by: Lennert Buytenhek <[email protected]> Cc: Wim Van Sebroeck <[email protected]> Cc: Russell King <[email protected]> Signed-off-by: Alessandro Zummo <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
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Alessandro Zummo
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Linus Torvalds
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Mar 25, 2006
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/* | ||
* Watchdog driver for Cirrus Logic EP93xx family of devices. | ||
* | ||
* Copyright (c) 2004 Ray Lehtiniemi | ||
* Copyright (c) 2006 Tower Technologies | ||
* Based on ep93xx driver, bits from alim7101_wdt.c | ||
* | ||
* Authors: Ray Lehtiniemi <[email protected]>, | ||
* Alessandro Zummo <[email protected]> | ||
* | ||
* 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. | ||
* | ||
* This watchdog fires after 250msec, which is a too short interval | ||
* for us to rely on the user space daemon alone. So we ping the | ||
* wdt each ~200msec and eventually stop doing it if the user space | ||
* daemon dies. | ||
* | ||
* TODO: | ||
* | ||
* - Test last reset from watchdog status | ||
* - Add a few missing ioctls | ||
*/ | ||
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#include <linux/module.h> | ||
#include <linux/fs.h> | ||
#include <linux/miscdevice.h> | ||
#include <linux/watchdog.h> | ||
#include <linux/timer.h> | ||
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#include <asm/hardware.h> | ||
#include <asm/uaccess.h> | ||
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#define WDT_VERSION "0.3" | ||
#define PFX "ep93xx_wdt: " | ||
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/* default timeout (secs) */ | ||
#define WDT_TIMEOUT 30 | ||
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static int nowayout = WATCHDOG_NOWAYOUT; | ||
static int timeout = WDT_TIMEOUT; | ||
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static struct timer_list timer; | ||
static unsigned long next_heartbeat; | ||
static unsigned long wdt_status; | ||
static unsigned long boot_status; | ||
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#define WDT_IN_USE 0 | ||
#define WDT_OK_TO_CLOSE 1 | ||
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#define EP93XX_WDT_REG(x) (EP93XX_WATCHDOG_BASE + (x)) | ||
#define EP93XX_WDT_WATCHDOG EP93XX_WDT_REG(0x00) | ||
#define EP93XX_WDT_WDSTATUS EP93XX_WDT_REG(0x04) | ||
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/* reset the wdt every ~200ms */ | ||
#define WDT_INTERVAL (HZ/5) | ||
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static void wdt_enable(void) | ||
{ | ||
__raw_writew(0xaaaa, EP93XX_WDT_WATCHDOG); | ||
} | ||
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static void wdt_disable(void) | ||
{ | ||
__raw_writew(0xaa55, EP93XX_WDT_WATCHDOG); | ||
} | ||
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static inline void wdt_ping(void) | ||
{ | ||
__raw_writew(0x5555, EP93XX_WDT_WATCHDOG); | ||
} | ||
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static void wdt_startup(void) | ||
{ | ||
next_heartbeat = jiffies + (timeout * HZ); | ||
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wdt_enable(); | ||
mod_timer(&timer, jiffies + WDT_INTERVAL); | ||
} | ||
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static void wdt_shutdown(void) | ||
{ | ||
del_timer_sync(&timer); | ||
wdt_disable(); | ||
} | ||
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static void wdt_keepalive(void) | ||
{ | ||
/* user land ping */ | ||
next_heartbeat = jiffies + (timeout * HZ); | ||
} | ||
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static int ep93xx_wdt_open(struct inode *inode, struct file *file) | ||
{ | ||
if (test_and_set_bit(WDT_IN_USE, &wdt_status)) | ||
return -EBUSY; | ||
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clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | ||
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wdt_startup(); | ||
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return nonseekable_open(inode, file); | ||
} | ||
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static ssize_t | ||
ep93xx_wdt_write(struct file *file, const char __user *data, size_t len, | ||
loff_t *ppos) | ||
{ | ||
/* Can't seek (pwrite) on this device */ | ||
if (*ppos != file->f_pos) | ||
return -ESPIPE; | ||
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if (len) { | ||
if (!nowayout) { | ||
size_t i; | ||
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clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | ||
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for (i = 0; i != len; i++) { | ||
char c; | ||
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if (get_user(c, data + i)) | ||
return -EFAULT; | ||
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if (c == 'V') | ||
set_bit(WDT_OK_TO_CLOSE, &wdt_status); | ||
else | ||
clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | ||
} | ||
} | ||
wdt_keepalive(); | ||
} | ||
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return len; | ||
} | ||
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static struct watchdog_info ident = { | ||
.options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE, | ||
.identity = "EP93xx Watchdog", | ||
}; | ||
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static int | ||
ep93xx_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, | ||
unsigned long arg) | ||
{ | ||
int ret = -ENOIOCTLCMD; | ||
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switch (cmd) { | ||
case WDIOC_GETSUPPORT: | ||
ret = copy_to_user((struct watchdog_info __user *)arg, &ident, | ||
sizeof(ident)) ? -EFAULT : 0; | ||
break; | ||
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case WDIOC_GETSTATUS: | ||
ret = put_user(0, (int __user *)arg); | ||
break; | ||
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case WDIOC_GETBOOTSTATUS: | ||
ret = put_user(boot_status, (int __user *)arg); | ||
break; | ||
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case WDIOC_GETTIMEOUT: | ||
/* actually, it is 0.250 seconds.... */ | ||
ret = put_user(1, (int __user *)arg); | ||
break; | ||
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case WDIOC_KEEPALIVE: | ||
wdt_keepalive(); | ||
ret = 0; | ||
break; | ||
} | ||
return ret; | ||
} | ||
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static int ep93xx_wdt_release(struct inode *inode, struct file *file) | ||
{ | ||
if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) | ||
wdt_shutdown(); | ||
else | ||
printk(KERN_CRIT PFX "Device closed unexpectedly - " | ||
"timer will not stop\n"); | ||
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clear_bit(WDT_IN_USE, &wdt_status); | ||
clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | ||
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return 0; | ||
} | ||
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static struct file_operations ep93xx_wdt_fops = { | ||
.owner = THIS_MODULE, | ||
.write = ep93xx_wdt_write, | ||
.ioctl = ep93xx_wdt_ioctl, | ||
.open = ep93xx_wdt_open, | ||
.release = ep93xx_wdt_release, | ||
}; | ||
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static struct miscdevice ep93xx_wdt_miscdev = { | ||
.minor = WATCHDOG_MINOR, | ||
.name = "watchdog", | ||
.fops = &ep93xx_wdt_fops, | ||
}; | ||
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static void ep93xx_timer_ping(unsigned long data) | ||
{ | ||
if (time_before(jiffies, next_heartbeat)) | ||
wdt_ping(); | ||
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/* Re-set the timer interval */ | ||
mod_timer(&timer, jiffies + WDT_INTERVAL); | ||
} | ||
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static int __init ep93xx_wdt_init(void) | ||
{ | ||
int err; | ||
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err = misc_register(&ep93xx_wdt_miscdev); | ||
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boot_status = __raw_readl(EP93XX_WDT_WATCHDOG) & 0x01 ? 1 : 0; | ||
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printk(KERN_INFO PFX "EP93XX watchdog, driver version " | ||
WDT_VERSION "%s\n", | ||
(__raw_readl(EP93XX_WDT_WATCHDOG) & 0x08) | ||
? " (nCS1 disable detected)" : ""); | ||
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if (timeout < 1 || timeout > 3600) { | ||
timeout = WDT_TIMEOUT; | ||
printk(KERN_INFO PFX | ||
"timeout value must be 1<=x<=3600, using %d\n", | ||
timeout); | ||
} | ||
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setup_timer(&timer, ep93xx_timer_ping, 1); | ||
return err; | ||
} | ||
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static void __exit ep93xx_wdt_exit(void) | ||
{ | ||
wdt_shutdown(); | ||
misc_deregister(&ep93xx_wdt_miscdev); | ||
} | ||
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module_init(ep93xx_wdt_init); | ||
module_exit(ep93xx_wdt_exit); | ||
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module_param(nowayout, int, 0); | ||
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); | ||
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module_param(timeout, int, 0); | ||
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); | ||
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MODULE_AUTHOR("Ray Lehtiniemi <[email protected]>," | ||
"Alessandro Zummo <[email protected]>"); | ||
MODULE_DESCRIPTION("EP93xx Watchdog"); | ||
MODULE_LICENSE("GPL"); | ||
MODULE_VERSION(WDT_VERSION); | ||
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |