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linux-next/drivers/watchdog/ib700wdt.c
Alexey Dobriyan c7dfd0cca3 [WATCHDOG] spin_lock_init() fixes 
Some watchdog drivers initialize global spinlocks in module's init function
which is tolerable, but some do it in PCI probe function.  So, switch to
static initialization to fix theoretical bugs and, more importantly, stop
giving people bad examples.

Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2007-11-02 19:09:07 +00:00

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/*
* 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/fs.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/system.h>
static struct platform_device *ibwdt_platform_device;
static unsigned long ibwdt_is_open;
static DEFINE_SPINLOCK(ibwdt_lock);
static char expect_close;
/* Module information */
#define DRV_NAME "ib700wdt"
#define PFX DRV_NAME ": "
/*
*
* 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=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
/*
* Watchdog Operations
*/
static void
ibwdt_ping(void)
{
spin_lock(&ibwdt_lock);
/* Write a watchdog value */
outb_p(wd_margin, WDT_START);
spin_unlock(&ibwdt_lock);
}
static void
ibwdt_disable(void)
{
spin_lock(&ibwdt_lock);
outb_p(0, WDT_STOP);
spin_unlock(&ibwdt_lock);
}
static int
ibwdt_set_heartbeat(int t)
{
int i;
if ((t < 0) || (t > 30))
return -EINVAL;
for (i = 0x0F; i > -1; i--)
if (wd_times[i] > t)
break;
wd_margin = i;
return 0;
}
/*
* /dev/watchdog handling
*/
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 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:
case WDIOC_GETBOOTSTATUS:
return put_user(0, p);
case WDIOC_KEEPALIVE:
ibwdt_ping();
break;
case WDIOC_SETTIMEOUT:
if (get_user(new_margin, p))
return -EFAULT;
if (ibwdt_set_heartbeat(new_margin))
return -EINVAL;
ibwdt_ping();
/* Fall */
case WDIOC_GETTIMEOUT:
return put_user(wd_times[wd_margin], p);
case WDIOC_SETOPTIONS:
{
int options, retval = -EINVAL;
if (get_user(options, p))
return -EFAULT;
if (options & WDIOS_DISABLECARD) {
ibwdt_disable();
retval = 0;
}
if (options & WDIOS_ENABLECARD) {
ibwdt_ping();
retval = 0;
}
return retval;
}
default:
return -ENOTTY;
}
return 0;
}
static int
ibwdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &ibwdt_is_open)) {
return -EBUSY;
}
if (nowayout)
__module_get(THIS_MODULE);
/* Activate */
ibwdt_ping();
return nonseekable_open(inode, file);
}
static int
ibwdt_close(struct inode *inode, struct file *file)
{
if (expect_close == 42) {
ibwdt_disable();
} else {
printk(KERN_CRIT PFX "WDT device closed unexpectedly. WDT will not stop!\n");
ibwdt_ping();
}
clear_bit(0, &ibwdt_is_open);
expect_close = 0;
return 0;
}
/*
* 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,
};
/*
* Init & exit routines
*/
static int __devinit ibwdt_probe(struct platform_device *dev)
{
int res;
#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 = misc_register(&ibwdt_miscdev);
if (res) {
printk (KERN_ERR PFX "failed to register misc device\n");
goto out_nomisc;
}
return 0;
out_nomisc:
release_region(WDT_START, 1);
out_nostartreg:
#if WDT_START != WDT_STOP
release_region(WDT_STOP, 1);
#endif
out_nostopreg:
return res;
}
static int __devexit ibwdt_remove(struct platform_device *dev)
{
misc_deregister(&ibwdt_miscdev);
release_region(WDT_START,1);
#if WDT_START != WDT_STOP
release_region(WDT_STOP,1);
#endif
return 0;
}
static void ibwdt_shutdown(struct platform_device *dev)
{
/* Turn the WDT off if we have a soft shutdown */
ibwdt_disable();
}
static struct platform_driver ibwdt_driver = {
.probe = ibwdt_probe,
.remove = __devexit_p(ibwdt_remove),
.shutdown = ibwdt_shutdown,
.driver = {
.owner = THIS_MODULE,
.name = DRV_NAME,
},
};
static int __init ibwdt_init(void)
{
int err;
printk(KERN_INFO PFX "WDT driver for IB700 single board computer initialising.\n");
err = platform_driver_register(&ibwdt_driver);
if (err)
return err;
ibwdt_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0);
if (IS_ERR(ibwdt_platform_device)) {
err = PTR_ERR(ibwdt_platform_device);
goto unreg_platform_driver;
}
return 0;
unreg_platform_driver:
platform_driver_unregister(&ibwdt_driver);
return err;
}
static void __exit ibwdt_exit(void)
{
platform_device_unregister(ibwdt_platform_device);
platform_driver_unregister(&ibwdt_driver);
printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
}
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 */
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