/* $Id: riowatchdog.c,v 1.3.2.2 2002/01/23 18:48:02 davem Exp $
* riowatchdog.c - driver for hw watchdog inside Super I/O of RIO
*
* Copyright (C) 2001 David S. Miller (davem@redhat.com)
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/miscdevice.h>
#include <asm/io.h>
#include <asm/ebus.h>
#include <asm/bbc.h>
#include <asm/oplib.h>
#include <asm/uaccess.h>
#include <asm/watchdog.h>
/* RIO uses the NatSemi Super I/O power management logical device
* as its' watchdog.
*
* When the watchdog triggers, it asserts a line to the BBC (Boot Bus
* Controller) of the machine. The BBC can only be configured to
* trigger a power-on reset when the signal is asserted. The BBC
* can be configured to ignore the signal entirely as well.
*
* The only Super I/O device register we care about is at index
* 0x05 (WDTO_INDEX) which is the watchdog time-out in minutes (1-255).
* If set to zero, this disables the watchdog. When set, the system
* must periodically (before watchdog expires) clear (set to zero) and
* re-set the watchdog else it will trigger.
*
* There are two other indexed watchdog registers inside this Super I/O
* logical device, but they are unused. The first, at index 0x06 is
* the watchdog control and can be used to make the watchdog timer re-set
* when the PS/2 mouse or serial lines show activity. The second, at
* index 0x07 is merely a sampling of the line from the watchdog to the
* BBC.
*
* The watchdog device generates no interrupts.
*/
MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
MODULE_DESCRIPTION("Hardware watchdog driver for Sun RIO");
MODULE_SUPPORTED_DEVICE("watchdog");
MODULE_LICENSE("GPL");
#define RIOWD_NAME "pmc"
#define RIOWD_MINOR 215
static DEFINE_SPINLOCK(riowd_lock);
static void __iomem *bbc_regs;
static void __iomem *riowd_regs;
#define WDTO_INDEX 0x05
static int riowd_timeout = 1; /* in minutes */
module_param(riowd_timeout, int, 0);
MODULE_PARM_DESC(riowd_timeout, "Watchdog timeout in minutes");
#if 0 /* Currently unused. */
static u8 riowd_readreg(int index)
{
unsigned long flags;
u8 ret;
spin_lock_irqsave(&riowd_lock, flags);
writeb(index, riowd_regs + 0);
ret = readb(riowd_regs + 1);
spin_unlock_irqrestore(&riowd_lock, flags);
return ret;
}
#endif
static void riowd_writereg(u8 val, int index)
{
unsigned long flags;
spin_lock_irqsave(&riowd_lock, flags);
writeb(index, riowd_regs + 0);
writeb(val, riowd_regs + 1);
spin_unlock_irqrestore(&riowd_lock, flags);
}
static void riowd_pingtimer(void)
{
riowd_writereg(riowd_timeout, WDTO_INDEX);
}
static void riowd_stoptimer(void)
{
u8 val;
riowd_writereg(0, WDTO_INDEX);
val = readb(bbc_regs + BBC_WDACTION);
val &= ~BBC_WDACTION_RST;
writeb(val, bbc_regs + BBC_WDACTION);
}
static void riowd_starttimer(void)
{
u8 val;
riowd_writereg(riowd_timeout, WDTO_INDEX);
val = readb(bbc_regs + BBC_WDACTION);
val |= BBC_WDACTION_RST;
writeb(val, bbc_regs + BBC_WDACTION);
}
static int riowd_open(struct inode *inode, struct file *filp)
{
nonseekable_open(inode, filp);
return 0;
}
static int riowd_release(struct inode *inode, struct file *filp)
{
return 0;
}
static int riowd_ioctl(struct inode *inode, struct file *filp,
unsigned int cmd, unsigned long arg)
{
static struct watchdog_info info = {
WDIOF_SETTIMEOUT, 0, "Natl. Semiconductor PC97317"
};
void __user *argp = (void __user *)arg;
unsigned int options;
int new_margin;
switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user(argp, &info, sizeof(info)))
return -EFAULT;
break;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
if (put_user(0, (int __user *)argp))
return -EFAULT;
break;
case WDIOC_KEEPALIVE:
riowd_pingtimer();
break;
case WDIOC_SETOPTIONS:
if (copy_from_user(&options, argp, sizeof(options)))
return -EFAULT;
if (options & WDIOS_DISABLECARD)
riowd_stoptimer();
else if (options & WDIOS_ENABLECARD)
riowd_starttimer();
else
return -EINVAL;
break;
case WDIOC_SETTIMEOUT:
if (get_user(new_margin, (int __user *)argp))
return -EFAULT;
if ((new_margin < 60) || (new_margin > (255 * 60)))
return -EINVAL;
riowd_timeout = (new_margin + 59) / 60;
riowd_pingtimer();
/* Fall */
case WDIOC_GETTIMEOUT:
return put_user(riowd_timeout * 60, (int __user *)argp);
default:
return -EINVAL;
};
return 0;
}
static ssize_t riowd_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
{
if (count) {
riowd_pingtimer();
return 1;
}
return 0;
}
static const struct file_operations riowd_fops = {
.owner = THIS_MODULE,
.ioctl = riowd_ioctl,
.open = riowd_open,
.write = riowd_write,
.release = riowd_release,
};
static struct miscdevice riowd_miscdev = { RIOWD_MINOR, RIOWD_NAME, &riowd_fops };
static int __init riowd_bbc_init(void)
{
struct linux_ebus *ebus = NULL;
struct linux_ebus_device *edev = NULL;
u8 val;
for_each_ebus(ebus) {
for_each_ebusdev(edev, ebus) {
if (!strcmp(edev->ofdev.node->name, "bbc"))
goto found_bbc;
}
}
found_bbc:
if (!edev)
return -ENODEV;
bbc_regs = ioremap(edev->resource[0].start, BBC_REGS_SIZE);
if (!bbc_regs)
return -ENODEV;
/* Turn it off. */
val = readb(bbc_regs + BBC_WDACTION);
val &= ~BBC_WDACTION_RST;
writeb(val, bbc_regs + BBC_WDACTION);
return 0;
}
static int __init riowd_init(void)
{
struct linux_ebus *ebus = NULL;
struct linux_ebus_device *edev = NULL;
for_each_ebus(ebus) {
for_each_ebusdev(edev, ebus) {
if (!strcmp(edev->ofdev.node->name, RIOWD_NAME))
goto ebus_done;
}
}
ebus_done:
if (!edev)
goto fail;
riowd_regs = ioremap(edev->resource[0].start, 2);
if (riowd_regs == NULL) {
printk(KERN_ERR "pmc: Cannot map registers.\n");
return -ENODEV;
}
if (riowd_bbc_init()) {
printk(KERN_ERR "pmc: Failure initializing BBC config.\n");
goto fail;
}
if (misc_register(&riowd_miscdev)) {
printk(KERN_ERR "pmc: Cannot register watchdog misc device.\n");
goto fail;
}
printk(KERN_INFO "pmc: Hardware watchdog [%i minutes], "
"regs at %p\n", riowd_timeout, riowd_regs);
return 0;
fail:
if (riowd_regs) {
iounmap(riowd_regs);
riowd_regs = NULL;
}
if (bbc_regs) {
iounmap(bbc_regs);
bbc_regs = NULL;
}
return -ENODEV;
}
static void __exit riowd_cleanup(void)
{
misc_deregister(&riowd_miscdev);
iounmap(riowd_regs);
riowd_regs = NULL;
iounmap(bbc_regs);
bbc_regs = NULL;
}
module_init(riowd_init);
module_exit(riowd_cleanup);
