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

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

#ifndef _WDT_H_
#define _WDT_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);
};

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