linux/drivers/char/watchdog/sa1100_wdt.c
Ian Campbell 9bbd037589 [PATCH] ARM: 2833/2: Remove support for WDIOF_MAGICCLOSE from sa1100-wdt
Patch from Ian Campbell

On PXA255 there is no way to disable the watchdog. Turning off OIER[E3]
as suggested in the existing comment does not work.

I posted a note to the ARM mailing list a little while ago asking for
opinions from people using SA1100. There was one reponse from Nico who
believes that the SA1100 is the same as the PXA255 in this respect.

You also asked me to involve the watchdog maintainer which I tried to
do but didn't hear anything back. There are only a couple of other
drivers which can't stop the watchdog and there seems to be no
consistancy regarding printing an error etc. I decided to print
something since that matches the case for all the other drivers when
NOWAYOUT is turned on.

Also, I changed the device .name to "watchdog" like most of the other
watchdogs. udev uses it as the device name (by default) and spaces etc.
get in the way.

Superceded 2833/1 because 2.6.13-rc4 caused rejects.

Signed-off-by: Ian Campbell <icampbell@arcom.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2005-08-03 20:34:52 +01:00

190 lines
4.3 KiB
C

/*
* Watchdog driver for the SA11x0/PXA2xx
*
* (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
* Based on SoftDog driver by Alan Cox <alan@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 Oleg Drokin nor iXcelerator.com admit liability nor provide
* warranty for any of this software. This material is provided
* "AS-IS" and at no charge.
*
* (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
*
* 27/11/2000 Initial release
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#ifdef CONFIG_ARCH_PXA
#include <asm/arch/pxa-regs.h>
#endif
#include <asm/hardware.h>
#include <asm/bitops.h>
#include <asm/uaccess.h>
#define OSCR_FREQ CLOCK_TICK_RATE
static unsigned long sa1100wdt_users;
static int pre_margin;
static int boot_status;
/*
* Allow only one person to hold it open
*/
static int sa1100dog_open(struct inode *inode, struct file *file)
{
nonseekable_open(inode, file);
if (test_and_set_bit(1,&sa1100wdt_users))
return -EBUSY;
/* Activate SA1100 Watchdog timer */
OSMR3 = OSCR + pre_margin;
OSSR = OSSR_M3;
OWER = OWER_WME;
OIER |= OIER_E3;
return 0;
}
/*
* The watchdog cannot be disabled.
*
* Previous comments suggested that turning off the interrupt by
* clearing OIER[E3] would prevent the watchdog timing out but this
* does not appear to be true (at least on the PXA255).
*/
static int sa1100dog_release(struct inode *inode, struct file *file)
{
printk(KERN_CRIT "WATCHDOG: Device closed - timer will not stop\n");
clear_bit(1, &sa1100wdt_users);
return 0;
}
static ssize_t sa1100dog_write(struct file *file, const char *data, size_t len, loff_t *ppos)
{
if (len)
/* Refresh OSMR3 timer. */
OSMR3 = OSCR + pre_margin;
return len;
}
static struct watchdog_info ident = {
.options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
.identity = "SA1100/PXA255 Watchdog",
};
static int sa1100dog_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
int ret = -ENOIOCTLCMD;
int time;
switch (cmd) {
case WDIOC_GETSUPPORT:
ret = copy_to_user((struct watchdog_info *)arg, &ident,
sizeof(ident)) ? -EFAULT : 0;
break;
case WDIOC_GETSTATUS:
ret = put_user(0, (int *)arg);
break;
case WDIOC_GETBOOTSTATUS:
ret = put_user(boot_status, (int *)arg);
break;
case WDIOC_SETTIMEOUT:
ret = get_user(time, (int *)arg);
if (ret)
break;
if (time <= 0 || time > 255) {
ret = -EINVAL;
break;
}
pre_margin = OSCR_FREQ * time;
OSMR3 = OSCR + pre_margin;
/*fall through*/
case WDIOC_GETTIMEOUT:
ret = put_user(pre_margin / OSCR_FREQ, (int *)arg);
break;
case WDIOC_KEEPALIVE:
OSMR3 = OSCR + pre_margin;
ret = 0;
break;
}
return ret;
}
static struct file_operations sa1100dog_fops =
{
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = sa1100dog_write,
.ioctl = sa1100dog_ioctl,
.open = sa1100dog_open,
.release = sa1100dog_release,
};
static struct miscdevice sa1100dog_miscdev =
{
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &sa1100dog_fops,
};
static int margin __initdata = 60; /* (secs) Default is 1 minute */
static int __init sa1100dog_init(void)
{
int ret;
/*
* Read the reset status, and save it for later. If
* we suspend, RCSR will be cleared, and the watchdog
* reset reason will be lost.
*/
boot_status = (RCSR & RCSR_WDR) ? WDIOF_CARDRESET : 0;
pre_margin = OSCR_FREQ * margin;
ret = misc_register(&sa1100dog_miscdev);
if (ret == 0)
printk("SA1100/PXA2xx Watchdog Timer: timer margin %d sec\n",
margin);
return ret;
}
static void __exit sa1100dog_exit(void)
{
misc_deregister(&sa1100dog_miscdev);
}
module_init(sa1100dog_init);
module_exit(sa1100dog_exit);
MODULE_AUTHOR("Oleg Drokin <green@crimea.edu>");
MODULE_DESCRIPTION("SA1100/PXA2xx Watchdog");
module_param(margin, int, 0);
MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);