2 * SBC EPX C3 0.1 A Hardware Watchdog Device for the Winsystems EPX-C3
3 * single board computer
5 * (c) Copyright 2006 Calin A. Culianu <calin@ajvar.org>, All Rights
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
13 * based on softdog.c by Alan Cox <alan@redhat.com>
16 #include <linux/module.h>
17 #include <linux/moduleparam.h>
18 #include <linux/config.h>
19 #include <linux/types.h>
20 #include <linux/kernel.h>
23 #include <linux/miscdevice.h>
24 #include <linux/watchdog.h>
25 #include <linux/notifier.h>
26 #include <linux/reboot.h>
27 #include <linux/init.h>
28 #include <linux/ioport.h>
29 #include <asm/uaccess.h>
32 #define PFX "epx_c3: "
33 static int epx_c3_alive
;
35 #define WATCHDOG_TIMEOUT 1 /* 1 sec default timeout */
37 static int nowayout
= WATCHDOG_NOWAYOUT
;
38 module_param(nowayout
, int, 0);
39 MODULE_PARM_DESC(nowayout
, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
41 #define EPXC3_WATCHDOG_CTL_REG 0x1ee /* write 1 to enable, 0 to disable */
42 #define EPXC3_WATCHDOG_PET_REG 0x1ef /* write anything to pet once enabled */
44 static void epx_c3_start(void)
46 outb(1, EPXC3_WATCHDOG_CTL_REG
);
49 static void epx_c3_stop(void)
52 outb(0, EPXC3_WATCHDOG_CTL_REG
);
54 printk(KERN_INFO PFX
"Stopped watchdog timer.\n");
57 static void epx_c3_pet(void)
59 outb(1, EPXC3_WATCHDOG_PET_REG
);
63 * Allow only one person to hold it open
65 static int epx_c3_open(struct inode
*inode
, struct file
*file
)
71 __module_get(THIS_MODULE
);
78 printk(KERN_INFO
"Started watchdog timer.\n");
80 return nonseekable_open(inode
, file
);
83 static int epx_c3_release(struct inode
*inode
, struct file
*file
)
85 /* Shut off the timer.
86 * Lock it in if it's a module and we defined ...NOWAYOUT */
88 epx_c3_stop(); /* Turn the WDT off */
95 static ssize_t
epx_c3_write(struct file
*file
, const char *data
,
96 size_t len
, loff_t
*ppos
)
98 /* Refresh the timer. */
104 static int epx_c3_ioctl(struct inode
*inode
, struct file
*file
,
105 unsigned int cmd
, unsigned long arg
)
107 int options
, retval
= -EINVAL
;
108 static struct watchdog_info ident
= {
109 .options
= WDIOF_KEEPALIVEPING
|
111 .firmware_version
= 0,
112 .identity
= "Winsystems EPX-C3 H/W Watchdog",
116 case WDIOC_GETSUPPORT
:
117 if (copy_to_user((struct watchdog_info
*)arg
,
118 &ident
, sizeof(ident
)))
121 case WDIOC_GETSTATUS
:
122 case WDIOC_GETBOOTSTATUS
:
123 return put_user(0,(int *)arg
);
124 case WDIOC_KEEPALIVE
:
127 case WDIOC_GETTIMEOUT
:
128 return put_user(WATCHDOG_TIMEOUT
,(int *)arg
);
129 case WDIOC_SETOPTIONS
: {
130 if (get_user(options
, (int *)arg
))
133 if (options
& WDIOS_DISABLECARD
) {
138 if (options
& WDIOS_ENABLECARD
) {
150 static int epx_c3_notify_sys(struct notifier_block
*this, unsigned long code
,
153 if (code
== SYS_DOWN
|| code
== SYS_HALT
)
154 epx_c3_stop(); /* Turn the WDT off */
159 static struct file_operations epx_c3_fops
= {
160 .owner
= THIS_MODULE
,
162 .write
= epx_c3_write
,
163 .ioctl
= epx_c3_ioctl
,
165 .release
= epx_c3_release
,
168 static struct miscdevice epx_c3_miscdev
= {
169 .minor
= WATCHDOG_MINOR
,
171 .fops
= &epx_c3_fops
,
174 static struct notifier_block epx_c3_notifier
= {
175 .notifier_call
= epx_c3_notify_sys
,
178 static const char banner
[] __initdata
=
179 KERN_INFO PFX
"Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n";
181 static int __init
watchdog_init(void)
185 if (!request_region(EPXC3_WATCHDOG_CTL_REG
, 2, "epxc3_watchdog"))
188 ret
= register_reboot_notifier(&epx_c3_notifier
);
190 printk(KERN_ERR PFX
"cannot register reboot notifier "
195 ret
= misc_register(&epx_c3_miscdev
);
197 printk(KERN_ERR PFX
"cannot register miscdev on minor=%d "
198 "(err=%d)\n", WATCHDOG_MINOR
, ret
);
199 unregister_reboot_notifier(&epx_c3_notifier
);
208 release_region(EPXC3_WATCHDOG_CTL_REG
, 2);
212 static void __exit
watchdog_exit(void)
214 misc_deregister(&epx_c3_miscdev
);
215 unregister_reboot_notifier(&epx_c3_notifier
);
216 release_region(EPXC3_WATCHDOG_CTL_REG
, 2);
219 module_init(watchdog_init
);
220 module_exit(watchdog_exit
);
222 MODULE_AUTHOR("Calin A. Culianu <calin@ajvar.org>");
223 MODULE_DESCRIPTION("Hardware Watchdog Device for Winsystems EPX-C3 SBC. Note that there is no way to probe for this device -- so only use it if you are *sure* you are runnning on this specific SBC system from Winsystems! It writes to IO ports 0x1ee and 0x1ef!");
224 MODULE_LICENSE("GPL");
225 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR
);