4 * (c) Copyright 2010 Novell, Inc.
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14 #define DRV_NAME "wdt"
15 #define DRV_VERSION "0.01"
17 #include <linux/bug.h>
18 #include <linux/errno.h>
20 #include <linux/hrtimer.h>
21 #include <linux/kernel.h>
22 #include <linux/ktime.h>
23 #include <linux/init.h>
24 #include <linux/miscdevice.h>
25 #include <linux/module.h>
26 #include <linux/moduleparam.h>
27 #include <linux/platform_device.h>
28 #include <linux/spinlock.h>
29 #include <linux/uaccess.h>
30 #include <linux/watchdog.h>
32 #include <asm/xen/hypercall.h>
33 #include <xen/interface/sched.h>
35 static struct platform_device
*platform_device
;
36 static DEFINE_SPINLOCK(wdt_lock
);
37 static struct sched_watchdog wdt
;
38 static __kernel_time_t wdt_expires
;
39 static bool is_active
, expect_release
;
41 #define WATCHDOG_TIMEOUT 60 /* in seconds */
42 static unsigned int timeout
= WATCHDOG_TIMEOUT
;
43 module_param(timeout
, uint
, S_IRUGO
);
44 MODULE_PARM_DESC(timeout
, "Watchdog timeout in seconds "
45 "(default=" __MODULE_STRING(WATCHDOG_TIMEOUT
) ")");
47 static bool nowayout
= WATCHDOG_NOWAYOUT
;
48 module_param(nowayout
, bool, S_IRUGO
);
49 MODULE_PARM_DESC(nowayout
, "Watchdog cannot be stopped once started "
50 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT
) ")");
52 static inline __kernel_time_t
set_timeout(void)
54 wdt
.timeout
= timeout
;
55 return ktime_to_timespec(ktime_get()).tv_sec
+ timeout
;
58 static int xen_wdt_start(void)
60 __kernel_time_t expires
;
65 expires
= set_timeout();
67 err
= HYPERVISOR_sched_op(SCHEDOP_watchdog
, &wdt
);
72 wdt_expires
= expires
;
77 spin_unlock(&wdt_lock
);
82 static int xen_wdt_stop(void)
90 err
= HYPERVISOR_sched_op(SCHEDOP_watchdog
, &wdt
);
94 spin_unlock(&wdt_lock
);
99 static int xen_wdt_kick(void)
101 __kernel_time_t expires
;
104 spin_lock(&wdt_lock
);
106 expires
= set_timeout();
108 err
= HYPERVISOR_sched_op(SCHEDOP_watchdog
, &wdt
);
112 wdt_expires
= expires
;
114 spin_unlock(&wdt_lock
);
119 static int xen_wdt_open(struct inode
*inode
, struct file
*file
)
123 /* /dev/watchdog can only be opened once */
124 if (xchg(&is_active
, true))
127 err
= xen_wdt_start();
129 err
= xen_wdt_kick();
130 return err
?: nonseekable_open(inode
, file
);
133 static int xen_wdt_release(struct inode
*inode
, struct file
*file
)
138 pr_crit("unexpected close, not stopping watchdog!\n");
142 expect_release
= false;
146 static ssize_t
xen_wdt_write(struct file
*file
, const char __user
*data
,
147 size_t len
, loff_t
*ppos
)
149 /* See if we got the magic character 'V' and reload the timer */
154 /* in case it was set long ago */
155 expect_release
= false;
157 /* scan to see whether or not we got the magic
159 for (i
= 0; i
!= len
; i
++) {
161 if (get_user(c
, data
+ i
))
164 expect_release
= true;
168 /* someone wrote to us, we should reload the timer */
174 static long xen_wdt_ioctl(struct file
*file
, unsigned int cmd
,
177 int new_options
, retval
= -EINVAL
;
179 int __user
*argp
= (void __user
*)arg
;
180 static const struct watchdog_info ident
= {
181 .options
= WDIOF_SETTIMEOUT
| WDIOF_MAGICCLOSE
,
182 .firmware_version
= 0,
183 .identity
= DRV_NAME
,
187 case WDIOC_GETSUPPORT
:
188 return copy_to_user(argp
, &ident
, sizeof(ident
)) ? -EFAULT
: 0;
190 case WDIOC_GETSTATUS
:
191 case WDIOC_GETBOOTSTATUS
:
192 return put_user(0, argp
);
194 case WDIOC_SETOPTIONS
:
195 if (get_user(new_options
, argp
))
198 if (new_options
& WDIOS_DISABLECARD
)
199 retval
= xen_wdt_stop();
200 if (new_options
& WDIOS_ENABLECARD
) {
201 retval
= xen_wdt_start();
202 if (retval
== -EBUSY
)
203 retval
= xen_wdt_kick();
207 case WDIOC_KEEPALIVE
:
211 case WDIOC_SETTIMEOUT
:
212 if (get_user(new_timeout
, argp
))
216 timeout
= new_timeout
;
219 case WDIOC_GETTIMEOUT
:
220 return put_user(timeout
, argp
);
222 case WDIOC_GETTIMELEFT
:
223 retval
= wdt_expires
- ktime_to_timespec(ktime_get()).tv_sec
;
224 return put_user(retval
, argp
);
230 static const struct file_operations xen_wdt_fops
= {
231 .owner
= THIS_MODULE
,
233 .write
= xen_wdt_write
,
234 .unlocked_ioctl
= xen_wdt_ioctl
,
235 .open
= xen_wdt_open
,
236 .release
= xen_wdt_release
,
239 static struct miscdevice xen_wdt_miscdev
= {
240 .minor
= WATCHDOG_MINOR
,
242 .fops
= &xen_wdt_fops
,
245 static int __devinit
xen_wdt_probe(struct platform_device
*dev
)
247 struct sched_watchdog wd
= { .id
= ~0 };
248 int ret
= HYPERVISOR_sched_op(SCHEDOP_watchdog
, &wd
);
253 timeout
= WATCHDOG_TIMEOUT
;
254 pr_info("timeout value invalid, using %d\n", timeout
);
257 ret
= misc_register(&xen_wdt_miscdev
);
259 pr_err("cannot register miscdev on minor=%d (%d)\n",
260 WATCHDOG_MINOR
, ret
);
264 pr_info("initialized (timeout=%ds, nowayout=%d)\n",
269 pr_info("not supported\n");
274 pr_info("bogus return value %d\n", ret
);
281 static int __devexit
xen_wdt_remove(struct platform_device
*dev
)
283 /* Stop the timer before we leave */
287 misc_deregister(&xen_wdt_miscdev
);
292 static void xen_wdt_shutdown(struct platform_device
*dev
)
297 static int xen_wdt_suspend(struct platform_device
*dev
, pm_message_t state
)
299 return xen_wdt_stop();
302 static int xen_wdt_resume(struct platform_device
*dev
)
304 return xen_wdt_start();
307 static struct platform_driver xen_wdt_driver
= {
308 .probe
= xen_wdt_probe
,
309 .remove
= __devexit_p(xen_wdt_remove
),
310 .shutdown
= xen_wdt_shutdown
,
311 .suspend
= xen_wdt_suspend
,
312 .resume
= xen_wdt_resume
,
314 .owner
= THIS_MODULE
,
319 static int __init
xen_wdt_init_module(void)
326 pr_info("Xen WatchDog Timer Driver v%s\n", DRV_VERSION
);
328 err
= platform_driver_register(&xen_wdt_driver
);
332 platform_device
= platform_device_register_simple(DRV_NAME
,
334 if (IS_ERR(platform_device
)) {
335 err
= PTR_ERR(platform_device
);
336 platform_driver_unregister(&xen_wdt_driver
);
342 static void __exit
xen_wdt_cleanup_module(void)
344 platform_device_unregister(platform_device
);
345 platform_driver_unregister(&xen_wdt_driver
);
346 pr_info("module unloaded\n");
349 module_init(xen_wdt_init_module
);
350 module_exit(xen_wdt_cleanup_module
);
352 MODULE_AUTHOR("Jan Beulich <jbeulich@novell.com>");
353 MODULE_DESCRIPTION("Xen WatchDog Timer Driver");
354 MODULE_VERSION(DRV_VERSION
);
355 MODULE_LICENSE("GPL");
356 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR
);