linux/drivers/watchdog/riowd.c

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/* riowd.c - driver for hw watchdog inside Super I/O of RIO
*
* Copyright (C) 2001, 2008 David S. Miller (davem@davemloft.net)
*/
#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 <linux/smp_lock.h>
#include <linux/watchdog.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <asm/io.h>
#include <asm/uaccess.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@davemloft.net>");
MODULE_DESCRIPTION("Hardware watchdog driver for Sun RIO");
MODULE_SUPPORTED_DEVICE("watchdog");
MODULE_LICENSE("GPL");
#define DRIVER_NAME "riowd"
#define PFX DRIVER_NAME ": "
struct riowd {
void __iomem *regs;
spinlock_t lock;
};
static struct riowd *riowd_device;
#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");
static void riowd_writereg(struct riowd *p, u8 val, int index)
{
unsigned long flags;
spin_lock_irqsave(&p->lock, flags);
writeb(index, p->regs + 0);
writeb(val, p->regs + 1);
spin_unlock_irqrestore(&p->lock, flags);
}
static int riowd_open(struct inode *inode, struct file *filp)
{
cycle_kernel_lock();
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 = {
.options = WDIOF_SETTIMEOUT,
.firmware_version = 1,
.identity = DRIVER_NAME,
};
void __user *argp = (void __user *)arg;
struct riowd *p = riowd_device;
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_writereg(p, riowd_timeout, WDTO_INDEX);
break;
case WDIOC_SETOPTIONS:
if (copy_from_user(&options, argp, sizeof(options)))
return -EFAULT;
if (options & WDIOS_DISABLECARD)
riowd_writereg(p, 0, WDTO_INDEX);
else if (options & WDIOS_ENABLECARD)
riowd_writereg(p, riowd_timeout, WDTO_INDEX);
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_writereg(p, riowd_timeout, WDTO_INDEX);
/* 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)
{
struct riowd *p = riowd_device;
if (count) {
riowd_writereg(p, riowd_timeout, WDTO_INDEX);
return 1;
}
return 0;
}
static const struct file_operations riowd_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.ioctl = riowd_ioctl,
.open = riowd_open,
.write = riowd_write,
.release = riowd_release,
};
static struct miscdevice riowd_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &riowd_fops
};
static int __devinit riowd_probe(struct of_device *op,
const struct of_device_id *match)
{
struct riowd *p;
int err = -EINVAL;
if (riowd_device)
goto out;
err = -ENOMEM;
p = kzalloc(sizeof(*p), GFP_KERNEL);
if (!p)
goto out;
spin_lock_init(&p->lock);
p->regs = of_ioremap(&op->resource[0], 0, 2, DRIVER_NAME);
if (!p->regs) {
printk(KERN_ERR PFX "Cannot map registers.\n");
goto out_free;
}
err = misc_register(&riowd_miscdev);
if (err) {
printk(KERN_ERR PFX "Cannot register watchdog misc device.\n");
goto out_iounmap;
}
printk(KERN_INFO PFX "Hardware watchdog [%i minutes], "
"regs at %p\n", riowd_timeout, p->regs);
dev_set_drvdata(&op->dev, p);
riowd_device = p;
err = 0;
out_iounmap:
of_iounmap(&op->resource[0], p->regs, 2);
out_free:
kfree(p);
out:
return err;
}
static int __devexit riowd_remove(struct of_device *op)
{
struct riowd *p = dev_get_drvdata(&op->dev);
misc_deregister(&riowd_miscdev);
of_iounmap(&op->resource[0], p->regs, 2);
kfree(p);
return 0;
}
static const struct of_device_id riowd_match[] = {
{
.name = "pmc",
},
{},
};
MODULE_DEVICE_TABLE(of, riowd_match);
static struct of_platform_driver riowd_driver = {
.name = DRIVER_NAME,
.match_table = riowd_match,
.probe = riowd_probe,
.remove = __devexit_p(riowd_remove),
};
static int __init riowd_init(void)
{
return of_register_driver(&riowd_driver, &of_bus_type);
}
static void __exit riowd_exit(void)
{
of_unregister_driver(&riowd_driver);
}
module_init(riowd_init);
module_exit(riowd_exit);