1 // SPDX-License-Identifier: GPL-2.0
5  * Copyright (C) 2008-2009 ST-Ericsson AB
6  * Watchdog driver for the ST-Ericsson AB COH 901 327 IP core
12 #include <linux/watchdog.h>
28 /* WDOG_FEED Register 32bit (-/W) */
34 /* WDOG_DISABLE1 Register 32bit (-/W) */
47 /* WDOG_COUNT Register 32bit (R/-) */
56 /* WDOG_RESTART Register 32bit (-/W) */
70 /* Default timeout in seconds = 1 minute */
83 static void coh901327_enable(u16 timeout)  in coh901327_enable()  argument
105 	/* Enable the watchdog interrupt */  in coh901327_enable()
107 	/* Activate the watchdog timer */  in coh901327_enable()
108 	writew(timeout, virtbase + U300_WDOG_TR);  in coh901327_enable()
109 	/* Start the watchdog timer */  in coh901327_enable()
112 	 * Extra read so that this change propagate in the watchdog.  in coh901327_enable()
118 			"%s(): watchdog not enabled! D2R value %04x\n",  in coh901327_enable()
126 	/* Disable the watchdog interrupt if it is active */  in coh901327_disable()
128 	/* If the watchdog is currently enabled, attempt to disable it */  in coh901327_disable()
142 			"%s(): watchdog not disabled! D2R value %04x\n",  in coh901327_disable()
148 	coh901327_enable(wdt_dev->timeout * 100);  in coh901327_start()
160 	/* Feed the watchdog */  in coh901327_ping()
169 	wdt_dev->timeout = time;  in coh901327_settimeout()
170 	/* Set new timeout value */  in coh901327_settimeout()
194  * This interrupt occurs 10 ms before the watchdog WILL bark.
204 	 * when the system is about to watchdog-reset, add them here!  in coh901327_interrupt()
206 	 * NOTE: on future versions of this IP-block, it will be possible  in coh901327_interrupt()
207 	 * to prevent a watchdog reset by feeding the watchdog at this  in coh901327_interrupt()
215 	dev_crit(parent, "watchdog is barking!\n");  in coh901327_interrupt()
237 	 * Max timeout is 327 since the 10ms
238 	 * timeout register is max
239 	 * 0x7FFF = 327670ms ~= 327s.
243 	.timeout = U300_WDOG_DEFAULT_TIMEOUT,
248 	struct device *dev = &pdev->dev;  in coh901327_probe()
273 		dev_info(dev, "watchdog timed out since last chip reset!\n");  in coh901327_probe()
300 	/* Reset the watchdog */  in coh901327_probe()
306 		ret = -EIO;  in coh901327_probe()
317 	dev_info(dev, "initialized. (timeout=%d sec)\n",  in coh901327_probe()
318 			coh901327_wdt.timeout);  in coh901327_probe()
339 	/* If watchdog is on, disable it here and now */  in coh901327_suspend()
347 	/* Restore the watchdog interrupt */  in coh901327_resume()
350 		/* Restart the watchdog timer */  in coh901327_resume()
364  * Mistreating the watchdog is the only way to perform a software reset of the
373 	 * Timeout = 5s, we have to wait for the watchdog reset to  in coh901327_watchdog_reset()
374 	 * actually take place: the watchdog will be reloaded with the  in coh901327_watchdog_reset()
377 	 * The boot loader will typically deactivate the watchdog, so we  in coh901327_watchdog_reset()
379 	 * deactivating the watchdog before it is shut down by it.  in coh901327_watchdog_reset()
381 	 * NOTE: on future versions of the watchdog, this restriction is  in coh901327_watchdog_reset()
382 	 * gone: the watchdog will be reloaded with a default value (1 min)  in coh901327_watchdog_reset()
383 	 * instead of last value, and you can conveniently set the watchdog  in coh901327_watchdog_reset()
384 	 * timeout to 10ms (value = 1) without any problems.  in coh901327_watchdog_reset()
408 MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");