[thirdparty/u-boot.git] / include / wdt.h

/* SPDX-License-Identifier: GPL-2.0+ */
/*
 * Copyright 2017 Google, Inc
 */

#ifndef _WDT_H_
#define _WDT_H_

#include <dm.h>
#include <dm/read.h>

/*
 * Implement a simple watchdog uclass. Watchdog is basically a timer that
 * is used to detect or recover from malfunction. During normal operation
 * the watchdog would be regularly reset to prevent it from timing out.
 * If, due to a hardware fault or program error, the computer fails to reset
 * the watchdog, the timer will elapse and generate a timeout signal.
 * The timeout signal is used to initiate corrective action or actions,
 * which typically include placing the system in a safe, known state.
 */

/*
 * Start the timer
 *
 * @dev: WDT Device
 * @timeout_ms: Number of ticks (milliseconds) before timer expires
 * @flags: Driver specific flags. This might be used to specify
 * which action needs to be executed when the timer expires
 * @return: 0 if OK, -ve on error
 */
int wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags);

/*
 * Stop the timer, thus disabling the Watchdog. Use wdt_start to start it again.
 *
 * @dev: WDT Device
 * @return: 0 if OK, -ve on error
 */
int wdt_stop(struct udevice *dev);

/*
 * Reset the timer, typically restoring the counter to
 * the value configured by start()
 *
 * @dev: WDT Device
 * @return: 0 if OK, -ve on error
 */
int wdt_reset(struct udevice *dev);

/*
 * Expire the timer, thus executing its action immediately.
 * This is typically used to reset the board or peripherals.
 *
 * @dev: WDT Device
 * @flags: Driver specific flags
 * @return 0 if OK -ve on error. If wdt action is system reset,
 * this function may never return.
 */
int wdt_expire_now(struct udevice *dev, ulong flags);

/*
 * struct wdt_ops - Driver model wdt operations
 *
 * The uclass interface is implemented by all wdt devices which use
 * driver model.
 */
struct wdt_ops {
	/*
	 * Start the timer
	 *
	 * @dev: WDT Device
	 * @timeout_ms: Number of ticks (milliseconds) before the timer expires
	 * @flags: Driver specific flags. This might be used to specify
	 * which action needs to be executed when the timer expires
	 * @return: 0 if OK, -ve on error
	 */
	int (*start)(struct udevice *dev, u64 timeout_ms, ulong flags);
	/*
	 * Stop the timer
	 *
	 * @dev: WDT Device
	 * @return: 0 if OK, -ve on error
	 */
	int (*stop)(struct udevice *dev);
	/*
	 * Reset the timer, typically restoring the counter to
	 * the value configured by start()
	 *
	 * @dev: WDT Device
	 * @return: 0 if OK, -ve on error
	 */
	int (*reset)(struct udevice *dev);
	/*
	 * Expire the timer, thus executing the action immediately (optional)
	 *
	 * If this function is not provided, a default implementation
	 * will be used, which sets the counter to 1
	 * and waits forever. This is good enough for system level
	 * reset, where the function is not expected to return, but might not be
	 * good enough for other use cases.
	 *
	 * @dev: WDT Device
	 * @flags: Driver specific flags
	 * @return 0 if OK -ve on error. May not return.
	 */
	int (*expire_now)(struct udevice *dev, ulong flags);
};

int initr_watchdog(void);

#endif  /* _WDT_H_ */
Commit	Line	Data
83d290c5	1	/* SPDX-License-Identifier: GPL-2.0+ */
0753bc2d	2	/*
0753bc2d	3	* Copyright 2017 Google, Inc
0753bc2d	4	*/
	5
	6	#ifndef _WDT_H_
	7	#define _WDT_H_
	8
06985289 SR	9	#include <dm.h>
	10	#include <dm/read.h>
	11
0753bc2d	12	/*
	13	* Implement a simple watchdog uclass. Watchdog is basically a timer that
	14	* is used to detect or recover from malfunction. During normal operation
	15	* the watchdog would be regularly reset to prevent it from timing out.
	16	* If, due to a hardware fault or program error, the computer fails to reset
	17	* the watchdog, the timer will elapse and generate a timeout signal.
	18	* The timeout signal is used to initiate corrective action or actions,
	19	* which typically include placing the system in a safe, known state.
	20	*/
	21
	22	/*
	23	* Start the timer
	24	*
	25	* @dev: WDT Device
ffdec300	26	* @timeout_ms: Number of ticks (milliseconds) before timer expires
0753bc2d	27	* @flags: Driver specific flags. This might be used to specify
	28	* which action needs to be executed when the timer expires
	29	* @return: 0 if OK, -ve on error
	30	*/
ffdec300	31	int wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags);
0753bc2d	32
	33	/*
	34	* Stop the timer, thus disabling the Watchdog. Use wdt_start to start it again.
	35	*
	36	* @dev: WDT Device
	37	* @return: 0 if OK, -ve on error
	38	*/
	39	int wdt_stop(struct udevice *dev);
	40
	41	/*
	42	* Reset the timer, typically restoring the counter to
	43	* the value configured by start()
	44	*
	45	* @dev: WDT Device
	46	* @return: 0 if OK, -ve on error
	47	*/
	48	int wdt_reset(struct udevice *dev);
	49
	50	/*
	51	* Expire the timer, thus executing its action immediately.
	52	* This is typically used to reset the board or peripherals.
	53	*
	54	* @dev: WDT Device
	55	* @flags: Driver specific flags
	56	* @return 0 if OK -ve on error. If wdt action is system reset,
	57	* this function may never return.
	58	*/
	59	int wdt_expire_now(struct udevice *dev, ulong flags);
	60
	61	/*
	62	* struct wdt_ops - Driver model wdt operations
	63	*
	64	* The uclass interface is implemented by all wdt devices which use
	65	* driver model.
	66	*/
	67	struct wdt_ops {
	68	/*
	69	* Start the timer
	70	*
	71	* @dev: WDT Device
ffdec300	72	* @timeout_ms: Number of ticks (milliseconds) before the timer expires
0753bc2d	73	* @flags: Driver specific flags. This might be used to specify
	74	* which action needs to be executed when the timer expires
	75	* @return: 0 if OK, -ve on error
	76	*/
ffdec300	77	int (start)(struct udevice dev, u64 timeout_ms, ulong flags);
0753bc2d	78	/*
	79	* Stop the timer
	80	*
	81	* @dev: WDT Device
	82	* @return: 0 if OK, -ve on error
	83	*/
	84	int (stop)(struct udevice dev);
	85	/*
	86	* Reset the timer, typically restoring the counter to
	87	* the value configured by start()
	88	*
	89	* @dev: WDT Device
	90	* @return: 0 if OK, -ve on error
	91	*/
	92	int (reset)(struct udevice dev);
	93	/*
	94	* Expire the timer, thus executing the action immediately (optional)
	95	*
	96	* If this function is not provided, a default implementation
	97	* will be used, which sets the counter to 1
	98	* and waits forever. This is good enough for system level
	99	* reset, where the function is not expected to return, but might not be
	100	* good enough for other use cases.
	101	*
	102	* @dev: WDT Device
	103	* @flags: Driver specific flags
	104	* @return 0 if OK -ve on error. May not return.
	105	*/
	106	int (expire_now)(struct udevice dev, ulong flags);
	107	};
	108
b4d9452c	109	int initr_watchdog(void);
06985289	110
0753bc2d	111	#endif /* _WDT_H_ */