mirror of
https://github.com/torvalds/linux
synced 2024-11-05 18:23:50 +00:00
fa21a580de
A platform_driver does not need to set an owner, it will be populated by the driver core. Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
363 lines
7.5 KiB
C
363 lines
7.5 KiB
C
/*
|
|
* Xen Watchdog Driver
|
|
*
|
|
* (c) Copyright 2010 Novell, Inc.
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
|
|
#define DRV_NAME "wdt"
|
|
#define DRV_VERSION "0.01"
|
|
|
|
#include <linux/bug.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/hrtimer.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/ktime.h>
|
|
#include <linux/init.h>
|
|
#include <linux/miscdevice.h>
|
|
#include <linux/module.h>
|
|
#include <linux/moduleparam.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/uaccess.h>
|
|
#include <linux/watchdog.h>
|
|
#include <xen/xen.h>
|
|
#include <asm/xen/hypercall.h>
|
|
#include <xen/interface/sched.h>
|
|
|
|
static struct platform_device *platform_device;
|
|
static DEFINE_SPINLOCK(wdt_lock);
|
|
static struct sched_watchdog wdt;
|
|
static __kernel_time_t wdt_expires;
|
|
static bool is_active, expect_release;
|
|
|
|
#define WATCHDOG_TIMEOUT 60 /* in seconds */
|
|
static unsigned int timeout = WATCHDOG_TIMEOUT;
|
|
module_param(timeout, uint, S_IRUGO);
|
|
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds "
|
|
"(default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
|
|
|
|
static bool nowayout = WATCHDOG_NOWAYOUT;
|
|
module_param(nowayout, bool, S_IRUGO);
|
|
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
|
|
"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
|
|
|
|
static inline __kernel_time_t set_timeout(void)
|
|
{
|
|
wdt.timeout = timeout;
|
|
return ktime_to_timespec(ktime_get()).tv_sec + timeout;
|
|
}
|
|
|
|
static int xen_wdt_start(void)
|
|
{
|
|
__kernel_time_t expires;
|
|
int err;
|
|
|
|
spin_lock(&wdt_lock);
|
|
|
|
expires = set_timeout();
|
|
if (!wdt.id)
|
|
err = HYPERVISOR_sched_op(SCHEDOP_watchdog, &wdt);
|
|
else
|
|
err = -EBUSY;
|
|
if (err > 0) {
|
|
wdt.id = err;
|
|
wdt_expires = expires;
|
|
err = 0;
|
|
} else
|
|
BUG_ON(!err);
|
|
|
|
spin_unlock(&wdt_lock);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int xen_wdt_stop(void)
|
|
{
|
|
int err = 0;
|
|
|
|
spin_lock(&wdt_lock);
|
|
|
|
wdt.timeout = 0;
|
|
if (wdt.id)
|
|
err = HYPERVISOR_sched_op(SCHEDOP_watchdog, &wdt);
|
|
if (!err)
|
|
wdt.id = 0;
|
|
|
|
spin_unlock(&wdt_lock);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int xen_wdt_kick(void)
|
|
{
|
|
__kernel_time_t expires;
|
|
int err;
|
|
|
|
spin_lock(&wdt_lock);
|
|
|
|
expires = set_timeout();
|
|
if (wdt.id)
|
|
err = HYPERVISOR_sched_op(SCHEDOP_watchdog, &wdt);
|
|
else
|
|
err = -ENXIO;
|
|
if (!err)
|
|
wdt_expires = expires;
|
|
|
|
spin_unlock(&wdt_lock);
|
|
|
|
return err;
|
|
}
|
|
|
|
static int xen_wdt_open(struct inode *inode, struct file *file)
|
|
{
|
|
int err;
|
|
|
|
/* /dev/watchdog can only be opened once */
|
|
if (xchg(&is_active, true))
|
|
return -EBUSY;
|
|
|
|
err = xen_wdt_start();
|
|
if (err == -EBUSY)
|
|
err = xen_wdt_kick();
|
|
return err ?: nonseekable_open(inode, file);
|
|
}
|
|
|
|
static int xen_wdt_release(struct inode *inode, struct file *file)
|
|
{
|
|
int err = 0;
|
|
|
|
if (expect_release)
|
|
err = xen_wdt_stop();
|
|
else {
|
|
pr_crit("unexpected close, not stopping watchdog!\n");
|
|
xen_wdt_kick();
|
|
}
|
|
is_active = err;
|
|
expect_release = false;
|
|
return err;
|
|
}
|
|
|
|
static ssize_t xen_wdt_write(struct file *file, const char __user *data,
|
|
size_t len, loff_t *ppos)
|
|
{
|
|
/* See if we got the magic character 'V' and reload the timer */
|
|
if (len) {
|
|
if (!nowayout) {
|
|
size_t i;
|
|
|
|
/* in case it was set long ago */
|
|
expect_release = false;
|
|
|
|
/* scan to see whether or not we got the magic
|
|
character */
|
|
for (i = 0; i != len; i++) {
|
|
char c;
|
|
if (get_user(c, data + i))
|
|
return -EFAULT;
|
|
if (c == 'V')
|
|
expect_release = true;
|
|
}
|
|
}
|
|
|
|
/* someone wrote to us, we should reload the timer */
|
|
xen_wdt_kick();
|
|
}
|
|
return len;
|
|
}
|
|
|
|
static long xen_wdt_ioctl(struct file *file, unsigned int cmd,
|
|
unsigned long arg)
|
|
{
|
|
int new_options, retval = -EINVAL;
|
|
int new_timeout;
|
|
int __user *argp = (void __user *)arg;
|
|
static const struct watchdog_info ident = {
|
|
.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
|
|
.firmware_version = 0,
|
|
.identity = DRV_NAME,
|
|
};
|
|
|
|
switch (cmd) {
|
|
case WDIOC_GETSUPPORT:
|
|
return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
|
|
|
|
case WDIOC_GETSTATUS:
|
|
case WDIOC_GETBOOTSTATUS:
|
|
return put_user(0, argp);
|
|
|
|
case WDIOC_SETOPTIONS:
|
|
if (get_user(new_options, argp))
|
|
return -EFAULT;
|
|
|
|
if (new_options & WDIOS_DISABLECARD)
|
|
retval = xen_wdt_stop();
|
|
if (new_options & WDIOS_ENABLECARD) {
|
|
retval = xen_wdt_start();
|
|
if (retval == -EBUSY)
|
|
retval = xen_wdt_kick();
|
|
}
|
|
return retval;
|
|
|
|
case WDIOC_KEEPALIVE:
|
|
xen_wdt_kick();
|
|
return 0;
|
|
|
|
case WDIOC_SETTIMEOUT:
|
|
if (get_user(new_timeout, argp))
|
|
return -EFAULT;
|
|
if (!new_timeout)
|
|
return -EINVAL;
|
|
timeout = new_timeout;
|
|
xen_wdt_kick();
|
|
/* fall through */
|
|
case WDIOC_GETTIMEOUT:
|
|
return put_user(timeout, argp);
|
|
|
|
case WDIOC_GETTIMELEFT:
|
|
retval = wdt_expires - ktime_to_timespec(ktime_get()).tv_sec;
|
|
return put_user(retval, argp);
|
|
}
|
|
|
|
return -ENOTTY;
|
|
}
|
|
|
|
static const struct file_operations xen_wdt_fops = {
|
|
.owner = THIS_MODULE,
|
|
.llseek = no_llseek,
|
|
.write = xen_wdt_write,
|
|
.unlocked_ioctl = xen_wdt_ioctl,
|
|
.open = xen_wdt_open,
|
|
.release = xen_wdt_release,
|
|
};
|
|
|
|
static struct miscdevice xen_wdt_miscdev = {
|
|
.minor = WATCHDOG_MINOR,
|
|
.name = "watchdog",
|
|
.fops = &xen_wdt_fops,
|
|
};
|
|
|
|
static int xen_wdt_probe(struct platform_device *dev)
|
|
{
|
|
struct sched_watchdog wd = { .id = ~0 };
|
|
int ret = HYPERVISOR_sched_op(SCHEDOP_watchdog, &wd);
|
|
|
|
switch (ret) {
|
|
case -EINVAL:
|
|
if (!timeout) {
|
|
timeout = WATCHDOG_TIMEOUT;
|
|
pr_info("timeout value invalid, using %d\n", timeout);
|
|
}
|
|
|
|
ret = misc_register(&xen_wdt_miscdev);
|
|
if (ret) {
|
|
pr_err("cannot register miscdev on minor=%d (%d)\n",
|
|
WATCHDOG_MINOR, ret);
|
|
break;
|
|
}
|
|
|
|
pr_info("initialized (timeout=%ds, nowayout=%d)\n",
|
|
timeout, nowayout);
|
|
break;
|
|
|
|
case -ENOSYS:
|
|
pr_info("not supported\n");
|
|
ret = -ENODEV;
|
|
break;
|
|
|
|
default:
|
|
pr_info("bogus return value %d\n", ret);
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int xen_wdt_remove(struct platform_device *dev)
|
|
{
|
|
/* Stop the timer before we leave */
|
|
if (!nowayout)
|
|
xen_wdt_stop();
|
|
|
|
misc_deregister(&xen_wdt_miscdev);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void xen_wdt_shutdown(struct platform_device *dev)
|
|
{
|
|
xen_wdt_stop();
|
|
}
|
|
|
|
static int xen_wdt_suspend(struct platform_device *dev, pm_message_t state)
|
|
{
|
|
typeof(wdt.id) id = wdt.id;
|
|
int rc = xen_wdt_stop();
|
|
|
|
wdt.id = id;
|
|
return rc;
|
|
}
|
|
|
|
static int xen_wdt_resume(struct platform_device *dev)
|
|
{
|
|
if (!wdt.id)
|
|
return 0;
|
|
wdt.id = 0;
|
|
return xen_wdt_start();
|
|
}
|
|
|
|
static struct platform_driver xen_wdt_driver = {
|
|
.probe = xen_wdt_probe,
|
|
.remove = xen_wdt_remove,
|
|
.shutdown = xen_wdt_shutdown,
|
|
.suspend = xen_wdt_suspend,
|
|
.resume = xen_wdt_resume,
|
|
.driver = {
|
|
.name = DRV_NAME,
|
|
},
|
|
};
|
|
|
|
static int __init xen_wdt_init_module(void)
|
|
{
|
|
int err;
|
|
|
|
if (!xen_domain())
|
|
return -ENODEV;
|
|
|
|
pr_info("Xen WatchDog Timer Driver v%s\n", DRV_VERSION);
|
|
|
|
err = platform_driver_register(&xen_wdt_driver);
|
|
if (err)
|
|
return err;
|
|
|
|
platform_device = platform_device_register_simple(DRV_NAME,
|
|
-1, NULL, 0);
|
|
if (IS_ERR(platform_device)) {
|
|
err = PTR_ERR(platform_device);
|
|
platform_driver_unregister(&xen_wdt_driver);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static void __exit xen_wdt_cleanup_module(void)
|
|
{
|
|
platform_device_unregister(platform_device);
|
|
platform_driver_unregister(&xen_wdt_driver);
|
|
pr_info("module unloaded\n");
|
|
}
|
|
|
|
module_init(xen_wdt_init_module);
|
|
module_exit(xen_wdt_cleanup_module);
|
|
|
|
MODULE_AUTHOR("Jan Beulich <jbeulich@novell.com>");
|
|
MODULE_DESCRIPTION("Xen WatchDog Timer Driver");
|
|
MODULE_VERSION(DRV_VERSION);
|
|
MODULE_LICENSE("GPL");
|