drivers/watchdog/sbc60xxwdt.c

1 // SPDX-License-Identifier: GPL-2.0-or-later
3  *	60xx Single Board Computer Watchdog Timer driver for Linux 2.2.x
8  *	any of this software. This material is provided "AS-IS" in
13  *           12/4 - 2000      [Initial revision]
14  *           25/4 - 2000      Added /dev/watchdog support
15  *           09/5 - 2001      [smj@oro.net] fixed fop_write to "return 1"
17  *           12/4 - 2002      [rob@osinvestor.com] eliminate fop_read
28  *           09/8 - 2003      [wim@iguana.be] cleanup of trailing spaces
30  *                            made timeout (the emulated heartbeat) a
39  *  *)  The driver will ping the watchdog by itself, because this
40  *      particular WDT has a very short timeout (one second) and it
53 #include <linux/watchdog.h>
67  * You must set these - The driver cannot probe for the settings
79  * The 60xx board can use watchdog timeout values from one second
81  * the watchdog every ~250ms we should be safe.
89  * char to /dev/watchdog every 30 seconds.
95 #define WATCHDOG_TIMEOUT 30		/* 30 sec default timeout */
96 static int timeout = WATCHDOG_TIMEOUT;	/* in seconds, multiplied by HZ to  variable
98 module_param(timeout, int, 0);
99 MODULE_PARM_DESC(timeout,
100 	"Watchdog timeout in seconds. (1<=timeout<=3600, default="
106 	"Watchdog cannot be stopped once started (default="
127 		/* Re-set the timer interval */  in wdt_timer_ping()
130 		pr_warn("Heartbeat lost! Will not ping the watchdog\n");  in wdt_timer_ping()
139 	next_heartbeat = jiffies + (timeout * HZ);  in wdt_startup()
143 	pr_info("Watchdog timer is now enabled\n");  in wdt_startup()
151 	pr_info("Watchdog timer is now disabled...\n");  in wdt_turnoff()
157 	next_heartbeat = jiffies + (timeout * HZ);  in wdt_keepalive()
161  * /dev/watchdog handling
181 					return -EFAULT;  in fop_write()
198 		return -EBUSY;  in fop_open()
234 		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;  in fop_ioctl()
240 		int new_options, retval = -EINVAL;  in fop_ioctl()
242 			return -EFAULT;  in fop_ioctl()
260 			return -EFAULT;  in fop_ioctl()
263 			return -EINVAL;  in fop_ioctl()
265 		timeout = new_timeout;  in fop_ioctl()
270 		return put_user(timeout, p);  in fop_ioctl()
272 		return -ENOTTY;  in fop_ioctl()
288 	.name = "watchdog",
328 	int rc = -EBUSY;  in sbc60xxwdt_init()
330 	if (timeout < 1 || timeout > 3600) { /* arbitrary upper limit */  in sbc60xxwdt_init()
331 		timeout = WATCHDOG_TIMEOUT;  in sbc60xxwdt_init()
332 		pr_info("timeout value must be 1 <= x <= 3600, using %d\n",  in sbc60xxwdt_init()
333 			timeout);  in sbc60xxwdt_init()
338 		rc = -EIO;  in sbc60xxwdt_init()
342 	/* We cannot reserve 0x45 - the kernel already has! */  in sbc60xxwdt_init()
346 			rc = -EIO;  in sbc60xxwdt_init()
363 	pr_info("WDT driver for 60XX single board computer initialised. timeout=%d sec (nowayout=%d)\n",  in sbc60xxwdt_init()
364 		timeout, nowayout);  in sbc60xxwdt_init()
383 MODULE_DESCRIPTION("60xx Single Board Computer Watchdog Timer driver");