1 /* drivers/char/watchdog/scx200_wdt.c
3 National Semiconductor SCx200 Watchdog support
5 Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
8 National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
9 (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>
11 This program is free software; you can redistribute it and/or
12 modify it under the terms of the GNU General Public License as
13 published by the Free Software Foundation; either version 2 of the
14 License, or (at your option) any later version.
16 The author(s) of this software shall not be held liable for damages
17 of any nature resulting due to the use of this software. This
18 software is provided AS-IS with no warranties. */
20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22 #include <linux/module.h>
23 #include <linux/moduleparam.h>
24 #include <linux/init.h>
25 #include <linux/miscdevice.h>
26 #include <linux/watchdog.h>
27 #include <linux/notifier.h>
28 #include <linux/reboot.h>
30 #include <linux/ioport.h>
31 #include <linux/scx200.h>
32 #include <linux/uaccess.h>
37 MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
38 MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver");
39 MODULE_LICENSE("GPL");
41 static int margin
= 60; /* in seconds */
42 module_param(margin
, int, 0);
43 MODULE_PARM_DESC(margin
, "Watchdog margin in seconds");
45 static bool nowayout
= WATCHDOG_NOWAYOUT
;
46 module_param(nowayout
, bool, 0);
47 MODULE_PARM_DESC(nowayout
, "Disable watchdog shutdown on close");
49 static u16 wdto_restart
;
50 static char expect_close
;
51 static unsigned long open_lock
;
52 static DEFINE_SPINLOCK(scx_lock
);
54 /* Bits of the WDCNFG register */
55 #define W_ENABLE 0x00fa /* Enable watchdog */
56 #define W_DISABLE 0x0000 /* Disable watchdog */
58 /* The scaling factor for the timer, this depends on the value of W_ENABLE */
59 #define W_SCALE (32768/1024)
61 static void scx200_wdt_ping(void)
64 outw(wdto_restart
, scx200_cb_base
+ SCx200_WDT_WDTO
);
65 spin_unlock(&scx_lock
);
68 static void scx200_wdt_update_margin(void)
70 pr_info("timer margin %d seconds\n", margin
);
71 wdto_restart
= margin
* W_SCALE
;
74 static void scx200_wdt_enable(void)
76 pr_debug("enabling watchdog timer, wdto_restart = %d\n", wdto_restart
);
79 outw(0, scx200_cb_base
+ SCx200_WDT_WDTO
);
80 outb(SCx200_WDT_WDSTS_WDOVF
, scx200_cb_base
+ SCx200_WDT_WDSTS
);
81 outw(W_ENABLE
, scx200_cb_base
+ SCx200_WDT_WDCNFG
);
82 spin_unlock(&scx_lock
);
87 static void scx200_wdt_disable(void)
89 pr_debug("disabling watchdog timer\n");
92 outw(0, scx200_cb_base
+ SCx200_WDT_WDTO
);
93 outb(SCx200_WDT_WDSTS_WDOVF
, scx200_cb_base
+ SCx200_WDT_WDSTS
);
94 outw(W_DISABLE
, scx200_cb_base
+ SCx200_WDT_WDCNFG
);
95 spin_unlock(&scx_lock
);
98 static int scx200_wdt_open(struct inode
*inode
, struct file
*file
)
100 /* only allow one at a time */
101 if (test_and_set_bit(0, &open_lock
))
105 return nonseekable_open(inode
, file
);
108 static int scx200_wdt_release(struct inode
*inode
, struct file
*file
)
110 if (expect_close
!= 42)
111 pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
113 scx200_wdt_disable();
115 clear_bit(0, &open_lock
);
120 static int scx200_wdt_notify_sys(struct notifier_block
*this,
121 unsigned long code
, void *unused
)
123 if (code
== SYS_HALT
|| code
== SYS_POWER_OFF
)
125 scx200_wdt_disable();
130 static struct notifier_block scx200_wdt_notifier
= {
131 .notifier_call
= scx200_wdt_notify_sys
,
134 static ssize_t
scx200_wdt_write(struct file
*file
, const char __user
*data
,
135 size_t len
, loff_t
*ppos
)
137 /* check for a magic close character */
144 for (i
= 0; i
< len
; ++i
) {
146 if (get_user(c
, data
+ i
))
158 static long scx200_wdt_ioctl(struct file
*file
, unsigned int cmd
,
161 void __user
*argp
= (void __user
*)arg
;
162 int __user
*p
= argp
;
163 static const struct watchdog_info ident
= {
164 .identity
= "NatSemi SCx200 Watchdog",
165 .firmware_version
= 1,
166 .options
= WDIOF_SETTIMEOUT
| WDIOF_KEEPALIVEPING
|
172 case WDIOC_GETSUPPORT
:
173 if (copy_to_user(argp
, &ident
, sizeof(ident
)))
176 case WDIOC_GETSTATUS
:
177 case WDIOC_GETBOOTSTATUS
:
181 case WDIOC_KEEPALIVE
:
184 case WDIOC_SETTIMEOUT
:
185 if (get_user(new_margin
, p
))
190 scx200_wdt_update_margin();
192 case WDIOC_GETTIMEOUT
:
193 if (put_user(margin
, p
))
201 static const struct file_operations scx200_wdt_fops
= {
202 .owner
= THIS_MODULE
,
204 .write
= scx200_wdt_write
,
205 .unlocked_ioctl
= scx200_wdt_ioctl
,
206 .open
= scx200_wdt_open
,
207 .release
= scx200_wdt_release
,
210 static struct miscdevice scx200_wdt_miscdev
= {
211 .minor
= WATCHDOG_MINOR
,
213 .fops
= &scx200_wdt_fops
,
216 static int __init
scx200_wdt_init(void)
220 pr_debug("NatSemi SCx200 Watchdog Driver\n");
222 /* check that we have found the configuration block */
223 if (!scx200_cb_present())
226 if (!request_region(scx200_cb_base
+ SCx200_WDT_OFFSET
,
228 "NatSemi SCx200 Watchdog")) {
229 pr_warn("watchdog I/O region busy\n");
233 scx200_wdt_update_margin();
234 scx200_wdt_disable();
236 r
= register_reboot_notifier(&scx200_wdt_notifier
);
238 pr_err("unable to register reboot notifier\n");
239 release_region(scx200_cb_base
+ SCx200_WDT_OFFSET
,
244 r
= misc_register(&scx200_wdt_miscdev
);
246 unregister_reboot_notifier(&scx200_wdt_notifier
);
247 release_region(scx200_cb_base
+ SCx200_WDT_OFFSET
,
255 static void __exit
scx200_wdt_cleanup(void)
257 misc_deregister(&scx200_wdt_miscdev
);
258 unregister_reboot_notifier(&scx200_wdt_notifier
);
259 release_region(scx200_cb_base
+ SCx200_WDT_OFFSET
,
263 module_init(scx200_wdt_init
);
264 module_exit(scx200_wdt_cleanup
);
268 compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules"