1 // SPDX-License-Identifier: GPL-2.0+
3 * Advantech Single Board Computer WDT driver
5 * (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
7 * Based on acquirewdt.c which is based on wdt.c.
8 * Original copyright messages:
10 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
11 * All Rights Reserved.
13 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
14 * warranty for any of this software. This material is provided
15 * "AS-IS" and at no charge.
17 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
19 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
20 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
22 * 16-Oct-2002 Rob Radez <rob@osinvestor.com>
23 * Clean up ioctls, clean up init + exit, add expect close support,
24 * add wdt_start and wdt_stop as parameters.
27 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
29 #include <linux/module.h>
30 #include <linux/moduleparam.h>
31 #include <linux/types.h>
32 #include <linux/miscdevice.h>
33 #include <linux/watchdog.h>
35 #include <linux/ioport.h>
36 #include <linux/platform_device.h>
37 #include <linux/init.h>
39 #include <linux/uaccess.h>
42 #define DRV_NAME "advantechwdt"
43 #define WATCHDOG_NAME "Advantech WDT"
44 #define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */
46 /* the watchdog platform device */
47 static struct platform_device *advwdt_platform_device;
48 static unsigned long advwdt_is_open;
49 static char adv_expect_close;
52 * You must set these - there is no sane way to probe for this board.
54 * To enable or restart, write the timeout value in seconds (1 to 63)
55 * to I/O port wdt_start. To disable, read I/O port wdt_stop.
56 * Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
57 * check your manual (at least the PCA-6159 seems to be different -
58 * the manual says wdt_stop is 0x43, not 0x443).
59 * (0x43 is also a write-only control register for the 8254 timer!)
62 static int wdt_stop = 0x443;
63 module_param(wdt_stop, int, 0);
64 MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
66 static int wdt_start = 0x443;
67 module_param(wdt_start, int, 0);
68 MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
70 static int timeout = WATCHDOG_TIMEOUT; /* in seconds */
71 module_param(timeout, int, 0);
72 MODULE_PARM_DESC(timeout,
73 "Watchdog timeout in seconds. 1<= timeout <=63, default="
74 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
76 static bool nowayout = WATCHDOG_NOWAYOUT;
77 module_param(nowayout, bool, 0);
78 MODULE_PARM_DESC(nowayout,
79 "Watchdog cannot be stopped once started (default="
80 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
86 static void advwdt_ping(void)
88 /* Write a watchdog value */
89 outb_p(timeout, wdt_start);
92 static void advwdt_disable(void)
97 static int advwdt_set_heartbeat(int t)
106 * /dev/watchdog handling
109 static ssize_t advwdt_write(struct file *file, const char __user *buf,
110 size_t count, loff_t *ppos)
116 adv_expect_close = 0;
118 for (i = 0; i != count; i++) {
120 if (get_user(c, buf + i))
123 adv_expect_close = 42;
131 static long advwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
134 void __user *argp = (void __user *)arg;
135 int __user *p = argp;
136 static const struct watchdog_info ident = {
137 .options = WDIOF_KEEPALIVEPING |
140 .firmware_version = 1,
141 .identity = WATCHDOG_NAME,
145 case WDIOC_GETSUPPORT:
146 if (copy_to_user(argp, &ident, sizeof(ident)))
150 case WDIOC_GETSTATUS:
151 case WDIOC_GETBOOTSTATUS:
152 return put_user(0, p);
154 case WDIOC_SETOPTIONS:
156 int options, retval = -EINVAL;
158 if (get_user(options, p))
160 if (options & WDIOS_DISABLECARD) {
164 if (options & WDIOS_ENABLECARD) {
170 case WDIOC_KEEPALIVE:
174 case WDIOC_SETTIMEOUT:
175 if (get_user(new_timeout, p))
177 if (advwdt_set_heartbeat(new_timeout))
181 case WDIOC_GETTIMEOUT:
182 return put_user(timeout, p);
189 static int advwdt_open(struct inode *inode, struct file *file)
191 if (test_and_set_bit(0, &advwdt_is_open))
198 return stream_open(inode, file);
201 static int advwdt_close(struct inode *inode, struct file *file)
203 if (adv_expect_close == 42) {
206 pr_crit("Unexpected close, not stopping watchdog!\n");
209 clear_bit(0, &advwdt_is_open);
210 adv_expect_close = 0;
218 static const struct file_operations advwdt_fops = {
219 .owner = THIS_MODULE,
221 .write = advwdt_write,
222 .unlocked_ioctl = advwdt_ioctl,
223 .compat_ioctl = compat_ptr_ioctl,
225 .release = advwdt_close,
228 static struct miscdevice advwdt_miscdev = {
229 .minor = WATCHDOG_MINOR,
231 .fops = &advwdt_fops,
235 * Init & exit routines
238 static int __init advwdt_probe(struct platform_device *dev)
242 if (wdt_stop != wdt_start) {
243 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
244 pr_err("I/O address 0x%04x already in use\n",
251 if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
252 pr_err("I/O address 0x%04x already in use\n", wdt_start);
257 /* Check that the heartbeat value is within it's range ;
258 * if not reset to the default */
259 if (advwdt_set_heartbeat(timeout)) {
260 advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
261 pr_info("timeout value must be 1<=x<=63, using %d\n", timeout);
264 ret = misc_register(&advwdt_miscdev);
266 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
267 WATCHDOG_MINOR, ret);
270 pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
275 release_region(wdt_start, 1);
277 if (wdt_stop != wdt_start)
278 release_region(wdt_stop, 1);
282 static int advwdt_remove(struct platform_device *dev)
284 misc_deregister(&advwdt_miscdev);
285 release_region(wdt_start, 1);
286 if (wdt_stop != wdt_start)
287 release_region(wdt_stop, 1);
292 static void advwdt_shutdown(struct platform_device *dev)
294 /* Turn the WDT off if we have a soft shutdown */
298 static struct platform_driver advwdt_driver = {
299 .remove = advwdt_remove,
300 .shutdown = advwdt_shutdown,
306 static int __init advwdt_init(void)
310 pr_info("WDT driver for Advantech single board computer initialising\n");
312 advwdt_platform_device = platform_device_register_simple(DRV_NAME,
314 if (IS_ERR(advwdt_platform_device))
315 return PTR_ERR(advwdt_platform_device);
317 err = platform_driver_probe(&advwdt_driver, advwdt_probe);
319 goto unreg_platform_device;
323 unreg_platform_device:
324 platform_device_unregister(advwdt_platform_device);
328 static void __exit advwdt_exit(void)
330 platform_device_unregister(advwdt_platform_device);
331 platform_driver_unregister(&advwdt_driver);
332 pr_info("Watchdog Module Unloaded\n");
335 module_init(advwdt_init);
336 module_exit(advwdt_exit);
338 MODULE_LICENSE("GPL");
339 MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
340 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");