mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson
synced 2025-10-31 08:26:29 +00:00
b7e04f8c61
move watchdog tree from drivers/char/watchdog to drivers/watchdog. Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
349 lines
8.8 KiB
C
349 lines
8.8 KiB
C
/*
|
|
* Acquire Single Board Computer Watchdog Timer driver
|
|
*
|
|
* Based on wdt.c. Original copyright messages:
|
|
*
|
|
* (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@redhat.com>
|
|
*
|
|
* 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
|
|
* Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
|
|
* Can't add timeout - driver doesn't allow changing value
|
|
*/
|
|
|
|
/*
|
|
* Theory of Operation:
|
|
* The Watch-Dog Timer is provided to ensure that standalone
|
|
* Systems can always recover from catastrophic conditions that
|
|
* caused the CPU to crash. This condition may have occured by
|
|
* external EMI or a software bug. When the CPU stops working
|
|
* correctly, hardware on the board will either perform a hardware
|
|
* reset (cold boot) or a non-maskable interrupt (NMI) to bring the
|
|
* system back to a known state.
|
|
*
|
|
* The Watch-Dog Timer is controlled by two I/O Ports.
|
|
* 443 hex - Read - Enable or refresh the Watch-Dog Timer
|
|
* 043 hex - Read - Disable the Watch-Dog Timer
|
|
*
|
|
* To enable the Watch-Dog Timer, a read from I/O port 443h must
|
|
* be performed. This will enable and activate the countdown timer
|
|
* which will eventually time out and either reset the CPU or cause
|
|
* an NMI depending on the setting of a jumper. To ensure that this
|
|
* reset condition does not occur, the Watch-Dog Timer must be
|
|
* periodically refreshed by reading the same I/O port 443h.
|
|
* The Watch-Dog Timer is disabled by reading I/O port 043h.
|
|
*
|
|
* The Watch-Dog Timer Time-Out Period is set via jumpers.
|
|
* It can be 1, 2, 10, 20, 110 or 220 seconds.
|
|
*/
|
|
|
|
/*
|
|
* Includes, defines, variables, module parameters, ...
|
|
*/
|
|
|
|
/* Includes */
|
|
#include <linux/module.h> /* For module specific items */
|
|
#include <linux/moduleparam.h> /* For new moduleparam's */
|
|
#include <linux/types.h> /* For standard types (like size_t) */
|
|
#include <linux/errno.h> /* For the -ENODEV/... values */
|
|
#include <linux/kernel.h> /* For printk/panic/... */
|
|
#include <linux/miscdevice.h> /* For MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR) */
|
|
#include <linux/watchdog.h> /* For the watchdog specific items */
|
|
#include <linux/fs.h> /* For file operations */
|
|
#include <linux/ioport.h> /* For io-port access */
|
|
#include <linux/platform_device.h> /* For platform_driver framework */
|
|
#include <linux/init.h> /* For __init/__exit/... */
|
|
|
|
#include <asm/uaccess.h> /* For copy_to_user/put_user/... */
|
|
#include <asm/io.h> /* For inb/outb/... */
|
|
|
|
/* Module information */
|
|
#define DRV_NAME "acquirewdt"
|
|
#define PFX DRV_NAME ": "
|
|
#define WATCHDOG_NAME "Acquire WDT"
|
|
#define WATCHDOG_HEARTBEAT 0 /* There is no way to see what the correct time-out period is */
|
|
|
|
/* internal variables */
|
|
static struct platform_device *acq_platform_device; /* the watchdog platform device */
|
|
static unsigned long acq_is_open;
|
|
static char expect_close;
|
|
|
|
/* module parameters */
|
|
static int wdt_stop = 0x43; /* You must set this - there is no sane way to probe for this board. */
|
|
module_param(wdt_stop, int, 0);
|
|
MODULE_PARM_DESC(wdt_stop, "Acquire WDT 'stop' io port (default 0x43)");
|
|
|
|
static int wdt_start = 0x443; /* You must set this - there is no sane way to probe for this board. */
|
|
module_param(wdt_start, int, 0);
|
|
MODULE_PARM_DESC(wdt_start, "Acquire WDT 'start' io port (default 0x443)");
|
|
|
|
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) ")");
|
|
|
|
/*
|
|
* Watchdog Operations
|
|
*/
|
|
|
|
static void acq_keepalive(void)
|
|
{
|
|
/* Write a watchdog value */
|
|
inb_p(wdt_start);
|
|
}
|
|
|
|
static void acq_stop(void)
|
|
{
|
|
/* Turn the card off */
|
|
inb_p(wdt_stop);
|
|
}
|
|
|
|
/*
|
|
* /dev/watchdog handling
|
|
*/
|
|
|
|
static ssize_t acq_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
|
|
{
|
|
/* See if we got the magic character 'V' and reload the timer */
|
|
if(count) {
|
|
if (!nowayout) {
|
|
size_t i;
|
|
|
|
/* note: just in case someone wrote the magic character
|
|
* five months ago... */
|
|
expect_close = 0;
|
|
|
|
/* scan to see whether or not we got the magic character */
|
|
for (i = 0; i != count; i++) {
|
|
char c;
|
|
if (get_user(c, buf + i))
|
|
return -EFAULT;
|
|
if (c == 'V')
|
|
expect_close = 42;
|
|
}
|
|
}
|
|
|
|
/* Well, anyhow someone wrote to us, we should return that favour */
|
|
acq_keepalive();
|
|
}
|
|
return count;
|
|
}
|
|
|
|
static int acq_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
|
|
unsigned long arg)
|
|
{
|
|
int options, retval = -EINVAL;
|
|
void __user *argp = (void __user *)arg;
|
|
int __user *p = argp;
|
|
static struct watchdog_info ident =
|
|
{
|
|
.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
|
|
.firmware_version = 1,
|
|
.identity = WATCHDOG_NAME,
|
|
};
|
|
|
|
switch(cmd)
|
|
{
|
|
case WDIOC_GETSUPPORT:
|
|
return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
|
|
|
|
case WDIOC_GETSTATUS:
|
|
case WDIOC_GETBOOTSTATUS:
|
|
return put_user(0, p);
|
|
|
|
case WDIOC_KEEPALIVE:
|
|
acq_keepalive();
|
|
return 0;
|
|
|
|
case WDIOC_GETTIMEOUT:
|
|
return put_user(WATCHDOG_HEARTBEAT, p);
|
|
|
|
case WDIOC_SETOPTIONS:
|
|
{
|
|
if (get_user(options, p))
|
|
return -EFAULT;
|
|
|
|
if (options & WDIOS_DISABLECARD)
|
|
{
|
|
acq_stop();
|
|
retval = 0;
|
|
}
|
|
|
|
if (options & WDIOS_ENABLECARD)
|
|
{
|
|
acq_keepalive();
|
|
retval = 0;
|
|
}
|
|
|
|
return retval;
|
|
}
|
|
|
|
default:
|
|
return -ENOTTY;
|
|
}
|
|
}
|
|
|
|
static int acq_open(struct inode *inode, struct file *file)
|
|
{
|
|
if (test_and_set_bit(0, &acq_is_open))
|
|
return -EBUSY;
|
|
|
|
if (nowayout)
|
|
__module_get(THIS_MODULE);
|
|
|
|
/* Activate */
|
|
acq_keepalive();
|
|
return nonseekable_open(inode, file);
|
|
}
|
|
|
|
static int acq_close(struct inode *inode, struct file *file)
|
|
{
|
|
if (expect_close == 42) {
|
|
acq_stop();
|
|
} else {
|
|
printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
|
|
acq_keepalive();
|
|
}
|
|
clear_bit(0, &acq_is_open);
|
|
expect_close = 0;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Kernel Interfaces
|
|
*/
|
|
|
|
static const struct file_operations acq_fops = {
|
|
.owner = THIS_MODULE,
|
|
.llseek = no_llseek,
|
|
.write = acq_write,
|
|
.ioctl = acq_ioctl,
|
|
.open = acq_open,
|
|
.release = acq_close,
|
|
};
|
|
|
|
static struct miscdevice acq_miscdev = {
|
|
.minor = WATCHDOG_MINOR,
|
|
.name = "watchdog",
|
|
.fops = &acq_fops,
|
|
};
|
|
|
|
/*
|
|
* Init & exit routines
|
|
*/
|
|
|
|
static int __devinit acq_probe(struct platform_device *dev)
|
|
{
|
|
int ret;
|
|
|
|
if (wdt_stop != wdt_start) {
|
|
if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
|
|
printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
|
|
wdt_stop);
|
|
ret = -EIO;
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
|
|
printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
|
|
wdt_start);
|
|
ret = -EIO;
|
|
goto unreg_stop;
|
|
}
|
|
|
|
ret = misc_register(&acq_miscdev);
|
|
if (ret != 0) {
|
|
printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
|
|
WATCHDOG_MINOR, ret);
|
|
goto unreg_regions;
|
|
}
|
|
|
|
printk (KERN_INFO PFX "initialized. (nowayout=%d)\n",
|
|
nowayout);
|
|
|
|
return 0;
|
|
|
|
unreg_regions:
|
|
release_region(wdt_start, 1);
|
|
unreg_stop:
|
|
if (wdt_stop != wdt_start)
|
|
release_region(wdt_stop, 1);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static int __devexit acq_remove(struct platform_device *dev)
|
|
{
|
|
misc_deregister(&acq_miscdev);
|
|
release_region(wdt_start,1);
|
|
if(wdt_stop != wdt_start)
|
|
release_region(wdt_stop,1);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void acq_shutdown(struct platform_device *dev)
|
|
{
|
|
/* Turn the WDT off if we have a soft shutdown */
|
|
acq_stop();
|
|
}
|
|
|
|
static struct platform_driver acquirewdt_driver = {
|
|
.probe = acq_probe,
|
|
.remove = __devexit_p(acq_remove),
|
|
.shutdown = acq_shutdown,
|
|
.driver = {
|
|
.owner = THIS_MODULE,
|
|
.name = DRV_NAME,
|
|
},
|
|
};
|
|
|
|
static int __init acq_init(void)
|
|
{
|
|
int err;
|
|
|
|
printk(KERN_INFO "WDT driver for Acquire single board computer initialising.\n");
|
|
|
|
err = platform_driver_register(&acquirewdt_driver);
|
|
if (err)
|
|
return err;
|
|
|
|
acq_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0);
|
|
if (IS_ERR(acq_platform_device)) {
|
|
err = PTR_ERR(acq_platform_device);
|
|
goto unreg_platform_driver;
|
|
}
|
|
|
|
return 0;
|
|
|
|
unreg_platform_driver:
|
|
platform_driver_unregister(&acquirewdt_driver);
|
|
return err;
|
|
}
|
|
|
|
static void __exit acq_exit(void)
|
|
{
|
|
platform_device_unregister(acq_platform_device);
|
|
platform_driver_unregister(&acquirewdt_driver);
|
|
printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
|
|
}
|
|
|
|
module_init(acq_init);
|
|
module_exit(acq_exit);
|
|
|
|
MODULE_AUTHOR("David Woodhouse");
|
|
MODULE_DESCRIPTION("Acquire Inc. Single Board Computer Watchdog Timer driver");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
|