1 // SPDX-License-Identifier: GPL-2.0-or-later
3  *	SMsC 37B787 Watchdog Timer driver for Linux 2.6.x.x
9  *	any of this software. This material is provided "AS-IS" in
12  *	(C) Copyright 2003-2006  Sven Anders <anders@anduras.de>
15  *	2003 - Created version 1.0 for Linux 2.4.x.
16  *	2006 - Ported to Linux 2.6, added nowayout and MAGICCLOSE
21  *	A Watchdog Timer (WDT) is a hardware circuit that can
26  *	via the /dev/watchdog special device file that userspace is
28  *	occurs, the driver will usually tell the hardware watchdog
29  *	that everything is in order, and that the watchdog should wait
32  *	notifications cease to occur, and the hardware watchdog will
36  *  mknod /dev/watchdog c 10 130
38  * For an example userspace keep-alive daemon, see:
39  *   Documentation/watchdog/wdt.rst
48 #include <linux/watchdog.h>
60 /* enable support for minutes as units? */
82 static DEFINE_SPINLOCK(io_lock);/* to guard the watchdog from io races */
86 /* -- Low level function ----------------------------------------*/
124 /* -- Medium level functions ------------------------------------*/
128 	/* -- General Purpose I/O Bit 1.2 --  in gpio_bit12()
131 	 * Bit 2,   Group Enable Intr.: 0 = Disable, 1 = Enable  in gpio_bit12()
142 	/* -- General Purpose I/O Bit 1.3 --  in gpio_bit13()
145 	 * Bit 2,  Group Enable Intr.: 0 = Disable, 1 = Enable  in gpio_bit13()
147 	 * Bit 4-6 (Reserved)  in gpio_bit13()
155 	/* -- Watchdog timer units --  in wdt_timer_units()
156 	 * Bit 0-6 (Reserved)  in wdt_timer_units()
157 	 * Bit 7,  WDT Time-out Value Units Select  in wdt_timer_units()
165 	/* -- Watchdog Timer Time-out Value --  in wdt_timeout_value()
166 	 * Bit 0-7 Binary coded units (0=Disabled, 1..255)  in wdt_timeout_value()
173 	/* -- Watchdog timer configuration --  in wdt_timer_conf()
174 	 * Bit 0   Joystick enable: 0* = No Reset, 1 = Reset WDT upon  in wdt_timer_conf()
176 	 * Bit 1   Keyboard enable: 0* = No Reset, 1 = Reset WDT upon KBD Intr.  in wdt_timer_conf()
177 	 * Bit 2   Mouse enable: 0* = No Reset, 1 = Reset WDT upon Mouse Intr  in wdt_timer_conf()
181 	 * Bit 4-7 WDT Interrupt Mapping: (0000* = Disabled,  in wdt_timer_conf()
189 	/* -- Watchdog timer control --  in wdt_timer_ctrl()
192 	 * Bit 2   Force Timeout: 1 = Forces WD timeout event (self-cleaning)  in wdt_timer_ctrl()
198 	 * -- Soft power management --  in wdt_timer_ctrl()
200 	 *            set via register 0xB8, (self-cleaning)  in wdt_timer_ctrl()
203 	 *            set via register 0xB8, (self-cleaning)  in wdt_timer_ctrl()
204 	 * Bit 7   SPOFF: 1 = Force software power down (self-cleaning)  in wdt_timer_ctrl()
209 /* -- Higher level functions ------------------------------------*/
211 /* initialize watchdog */
221 	/* enable the watchdog */  in wb_smsc_wdt_initialize()
239 	/* set the watchdog timer units */  in wb_smsc_wdt_initialize()
246 /* shutdown the watchdog */
254 	/* disable the watchdog */  in wb_smsc_wdt_shutdown()
258 	/* reset watchdog config register */  in wb_smsc_wdt_shutdown()
261 	/* reset watchdog control register */  in wb_smsc_wdt_shutdown()
271 /* set timeout => enable watchdog */
279 	/* set Power LED to blink, if we enable the timeout */  in wb_smsc_wdt_set_timeout()
305 /* disable watchdog */
309 	/* set the timeout to 0 to disable the watchdog */  in wb_smsc_wdt_disable()
313 /* enable watchdog by setting the current timeout */
337 /* return, if the watchdog is enabled (timeout is set...) */
345 /* -- File operations -------------------------------------------*/
347 /* open => enable watchdog and set initial timeout */
351 	/* /dev/watchdog can only be opened once */  in wb_smsc_wdt_open()
354 		return -EBUSY;  in wb_smsc_wdt_open()
362 	pr_info("Watchdog enabled. Timeout set to %d %s\n",  in wb_smsc_wdt_open()
376 		pr_info("Watchdog disabled, sleeping again...\n");  in wb_smsc_wdt_release()
378 		pr_crit("Unexpected close, not stopping watchdog!\n");  in wb_smsc_wdt_release()
405 					return -EFAULT;  in wb_smsc_wdt_write()
434 		.identity =		"SMsC 37B787 Watchdog",  in wb_smsc_wdt_ioctl()
442 								? -EFAULT : 0;  in wb_smsc_wdt_ioctl()
449 		int options, retval = -EINVAL;  in wb_smsc_wdt_ioctl()
452 			return -EFAULT;  in wb_smsc_wdt_ioctl()
469 			return -EFAULT;  in wb_smsc_wdt_ioctl()
474 			return -EINVAL;  in wb_smsc_wdt_ioctl()
484 		return -ENOTTY;  in wb_smsc_wdt_ioctl()
488 /* -- Notifier funtions -----------------------------------------*/
494 		/* set timeout to 0, to avoid possible race-condition */  in wb_smsc_wdt_notify_sys()
501 /* -- Module's structures ---------------------------------------*/
518 	.name		= "watchdog",
522 /* -- Module init functions -------------------------------------*/
530 	pr_info("SMsC 37B787 watchdog component driver "  in wb_smsc_wdt_init()
533 	if (!request_region(IOPORT, IOPORT_SIZE, "SMsC 37B787 watchdog")) {  in wb_smsc_wdt_init()
535 		ret = -EBUSY;  in wb_smsc_wdt_init()
543 	/* init the watchdog timer */  in wb_smsc_wdt_init()
562 	pr_info("Watchdog initialized and sleeping (nowayout=%d)...\n",  in wb_smsc_wdt_init()
584 		pr_info("Watchdog disabled\n");  in wb_smsc_wdt_exit()
591 	pr_info("SMsC 37B787 watchdog component driver removed\n");  in wb_smsc_wdt_exit()
598 MODULE_DESCRIPTION("Driver for SMsC 37B787 watchdog component (Version "
609 MODULE_PARM_DESC(timeout, "range is 1-255 units, default is 60");
613 		"Watchdog cannot be stopped once started (default="