forked from Minki/linux
62322d2554
Mark the static struct file_operations in drivers/char as const. Making them const prevents accidental bugs, and moves them to the .rodata section so that they no longer do any false sharing; in addition with the proper debug option they are then protected against corruption.. [akpm@osdl.org: build fix] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
347 lines
7.6 KiB
C
347 lines
7.6 KiB
C
/*
|
|
* IB700 Single Board Computer WDT driver
|
|
*
|
|
* (c) Copyright 2001 Charles Howes <chowes@vsol.net>
|
|
*
|
|
* Based on advantechwdt.c which is based on acquirewdt.c which
|
|
* is based on wdt.c.
|
|
*
|
|
* (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
|
|
*
|
|
* Based on acquirewdt.c which is 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
|
|
* Added timeout module option to override default
|
|
*
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/types.h>
|
|
#include <linux/miscdevice.h>
|
|
#include <linux/watchdog.h>
|
|
#include <linux/ioport.h>
|
|
#include <linux/notifier.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/reboot.h>
|
|
#include <linux/init.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/moduleparam.h>
|
|
|
|
#include <asm/io.h>
|
|
#include <asm/uaccess.h>
|
|
#include <asm/system.h>
|
|
|
|
static unsigned long ibwdt_is_open;
|
|
static spinlock_t ibwdt_lock;
|
|
static char expect_close;
|
|
|
|
#define PFX "ib700wdt: "
|
|
|
|
/*
|
|
*
|
|
* Watchdog Timer Configuration
|
|
*
|
|
* The function of the watchdog timer is to reset the system
|
|
* automatically and is defined at I/O port 0443H. To enable the
|
|
* watchdog timer and allow the system to reset, write I/O port 0443H.
|
|
* To disable the timer, write I/O port 0441H for the system to stop the
|
|
* watchdog function. The timer has a tolerance of 20% for its
|
|
* intervals.
|
|
*
|
|
* The following describes how the timer should be programmed.
|
|
*
|
|
* Enabling Watchdog:
|
|
* MOV AX,000FH (Choose the values from 0 to F)
|
|
* MOV DX,0443H
|
|
* OUT DX,AX
|
|
*
|
|
* Disabling Watchdog:
|
|
* MOV AX,000FH (Any value is fine.)
|
|
* MOV DX,0441H
|
|
* OUT DX,AX
|
|
*
|
|
* Watchdog timer control table:
|
|
* Level Value Time/sec | Level Value Time/sec
|
|
* 1 F 0 | 9 7 16
|
|
* 2 E 2 | 10 6 18
|
|
* 3 D 4 | 11 5 20
|
|
* 4 C 6 | 12 4 22
|
|
* 5 B 8 | 13 3 24
|
|
* 6 A 10 | 14 2 26
|
|
* 7 9 12 | 15 1 28
|
|
* 8 8 14 | 16 0 30
|
|
*
|
|
*/
|
|
|
|
static int wd_times[] = {
|
|
30, /* 0x0 */
|
|
28, /* 0x1 */
|
|
26, /* 0x2 */
|
|
24, /* 0x3 */
|
|
22, /* 0x4 */
|
|
20, /* 0x5 */
|
|
18, /* 0x6 */
|
|
16, /* 0x7 */
|
|
14, /* 0x8 */
|
|
12, /* 0x9 */
|
|
10, /* 0xA */
|
|
8, /* 0xB */
|
|
6, /* 0xC */
|
|
4, /* 0xD */
|
|
2, /* 0xE */
|
|
0, /* 0xF */
|
|
};
|
|
|
|
#define WDT_STOP 0x441
|
|
#define WDT_START 0x443
|
|
|
|
/* Default timeout */
|
|
#define WD_TIMO 0 /* 30 seconds +/- 20%, from table */
|
|
|
|
static int wd_margin = WD_TIMO;
|
|
|
|
static int nowayout = WATCHDOG_NOWAYOUT;
|
|
module_param(nowayout, int, 0);
|
|
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
|
|
|
|
|
|
/*
|
|
* Kernel methods.
|
|
*/
|
|
|
|
static void
|
|
ibwdt_ping(void)
|
|
{
|
|
/* Write a watchdog value */
|
|
outb_p(wd_margin, WDT_START);
|
|
}
|
|
|
|
static ssize_t
|
|
ibwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
|
|
{
|
|
if (count) {
|
|
if (!nowayout) {
|
|
size_t i;
|
|
|
|
/* In case it was set long ago */
|
|
expect_close = 0;
|
|
|
|
for (i = 0; i != count; i++) {
|
|
char c;
|
|
if (get_user(c, buf + i))
|
|
return -EFAULT;
|
|
if (c == 'V')
|
|
expect_close = 42;
|
|
}
|
|
}
|
|
ibwdt_ping();
|
|
}
|
|
return count;
|
|
}
|
|
|
|
static int
|
|
ibwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
|
|
unsigned long arg)
|
|
{
|
|
int i, new_margin;
|
|
void __user *argp = (void __user *)arg;
|
|
int __user *p = argp;
|
|
|
|
static struct watchdog_info ident = {
|
|
.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
|
|
.firmware_version = 1,
|
|
.identity = "IB700 WDT",
|
|
};
|
|
|
|
switch (cmd) {
|
|
case WDIOC_GETSUPPORT:
|
|
if (copy_to_user(argp, &ident, sizeof(ident)))
|
|
return -EFAULT;
|
|
break;
|
|
|
|
case WDIOC_GETSTATUS:
|
|
return put_user(0, p);
|
|
|
|
case WDIOC_KEEPALIVE:
|
|
ibwdt_ping();
|
|
break;
|
|
|
|
case WDIOC_SETTIMEOUT:
|
|
if (get_user(new_margin, p))
|
|
return -EFAULT;
|
|
if ((new_margin < 0) || (new_margin > 30))
|
|
return -EINVAL;
|
|
for (i = 0x0F; i > -1; i--)
|
|
if (wd_times[i] > new_margin)
|
|
break;
|
|
wd_margin = i;
|
|
ibwdt_ping();
|
|
/* Fall */
|
|
|
|
case WDIOC_GETTIMEOUT:
|
|
return put_user(wd_times[wd_margin], p);
|
|
break;
|
|
|
|
default:
|
|
return -ENOIOCTLCMD;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
ibwdt_open(struct inode *inode, struct file *file)
|
|
{
|
|
spin_lock(&ibwdt_lock);
|
|
if (test_and_set_bit(0, &ibwdt_is_open)) {
|
|
spin_unlock(&ibwdt_lock);
|
|
return -EBUSY;
|
|
}
|
|
if (nowayout)
|
|
__module_get(THIS_MODULE);
|
|
|
|
/* Activate */
|
|
ibwdt_ping();
|
|
spin_unlock(&ibwdt_lock);
|
|
return nonseekable_open(inode, file);
|
|
}
|
|
|
|
static int
|
|
ibwdt_close(struct inode *inode, struct file *file)
|
|
{
|
|
spin_lock(&ibwdt_lock);
|
|
if (expect_close == 42)
|
|
outb_p(0, WDT_STOP);
|
|
else
|
|
printk(KERN_CRIT PFX "WDT device closed unexpectedly. WDT will not stop!\n");
|
|
|
|
clear_bit(0, &ibwdt_is_open);
|
|
expect_close = 0;
|
|
spin_unlock(&ibwdt_lock);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Notifier for system down
|
|
*/
|
|
|
|
static int
|
|
ibwdt_notify_sys(struct notifier_block *this, unsigned long code,
|
|
void *unused)
|
|
{
|
|
if (code == SYS_DOWN || code == SYS_HALT) {
|
|
/* Turn the WDT off */
|
|
outb_p(0, WDT_STOP);
|
|
}
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
/*
|
|
* Kernel Interfaces
|
|
*/
|
|
|
|
static const struct file_operations ibwdt_fops = {
|
|
.owner = THIS_MODULE,
|
|
.llseek = no_llseek,
|
|
.write = ibwdt_write,
|
|
.ioctl = ibwdt_ioctl,
|
|
.open = ibwdt_open,
|
|
.release = ibwdt_close,
|
|
};
|
|
|
|
static struct miscdevice ibwdt_miscdev = {
|
|
.minor = WATCHDOG_MINOR,
|
|
.name = "watchdog",
|
|
.fops = &ibwdt_fops,
|
|
};
|
|
|
|
/*
|
|
* The WDT needs to learn about soft shutdowns in order to
|
|
* turn the timebomb registers off.
|
|
*/
|
|
|
|
static struct notifier_block ibwdt_notifier = {
|
|
.notifier_call = ibwdt_notify_sys,
|
|
};
|
|
|
|
static int __init ibwdt_init(void)
|
|
{
|
|
int res;
|
|
|
|
printk(KERN_INFO PFX "WDT driver for IB700 single board computer initialising.\n");
|
|
|
|
spin_lock_init(&ibwdt_lock);
|
|
res = misc_register(&ibwdt_miscdev);
|
|
if (res) {
|
|
printk (KERN_ERR PFX "failed to register misc device\n");
|
|
goto out_nomisc;
|
|
}
|
|
|
|
#if WDT_START != WDT_STOP
|
|
if (!request_region(WDT_STOP, 1, "IB700 WDT")) {
|
|
printk (KERN_ERR PFX "STOP method I/O %X is not available.\n", WDT_STOP);
|
|
res = -EIO;
|
|
goto out_nostopreg;
|
|
}
|
|
#endif
|
|
|
|
if (!request_region(WDT_START, 1, "IB700 WDT")) {
|
|
printk (KERN_ERR PFX "START method I/O %X is not available.\n", WDT_START);
|
|
res = -EIO;
|
|
goto out_nostartreg;
|
|
}
|
|
res = register_reboot_notifier(&ibwdt_notifier);
|
|
if (res) {
|
|
printk (KERN_ERR PFX "Failed to register reboot notifier.\n");
|
|
goto out_noreboot;
|
|
}
|
|
return 0;
|
|
|
|
out_noreboot:
|
|
release_region(WDT_START, 1);
|
|
out_nostartreg:
|
|
#if WDT_START != WDT_STOP
|
|
release_region(WDT_STOP, 1);
|
|
#endif
|
|
out_nostopreg:
|
|
misc_deregister(&ibwdt_miscdev);
|
|
out_nomisc:
|
|
return res;
|
|
}
|
|
|
|
static void __exit
|
|
ibwdt_exit(void)
|
|
{
|
|
misc_deregister(&ibwdt_miscdev);
|
|
unregister_reboot_notifier(&ibwdt_notifier);
|
|
#if WDT_START != WDT_STOP
|
|
release_region(WDT_STOP,1);
|
|
#endif
|
|
release_region(WDT_START,1);
|
|
}
|
|
|
|
module_init(ibwdt_init);
|
|
module_exit(ibwdt_exit);
|
|
|
|
MODULE_AUTHOR("Charles Howes <chowes@vsol.net>");
|
|
MODULE_DESCRIPTION("IB700 SBC watchdog driver");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
|
|
|
|
/* end of ib700wdt.c */
|