Git Repo - J-u-boot.git/blame_incremental

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Commit	Line	Data
	1	/* SPDX-License-Identifier: GPL-2.0+ */
	2	/*
	3	* Copyright 2017 Google, Inc
	4	*/
	5
	6	#ifndef _WDT_H_
	7	#define _WDT_H_
	8
	9	struct udevice;
	10
	11	/*
	12	* Implement a simple watchdog uclass. Watchdog is basically a timer that
	13	* is used to detect or recover from malfunction. During normal operation
	14	* the watchdog would be regularly reset to prevent it from timing out.
	15	* If, due to a hardware fault or program error, the computer fails to reset
	16	* the watchdog, the timer will elapse and generate a timeout signal.
	17	* The timeout signal is used to initiate corrective action or actions,
	18	* which typically include placing the system in a safe, known state.
	19	*/
	20
	21	/*
	22	* Start the timer
	23	*
	24	* @dev: WDT Device
	25	* @timeout_ms: Number of ticks (milliseconds) before timer expires
	26	* @flags: Driver specific flags. This might be used to specify
	27	* which action needs to be executed when the timer expires
	28	* @return: 0 if OK, -ve on error
	29	*/
	30	int wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags);
	31
	32	/*
	33	* Stop the timer, thus disabling the Watchdog. Use wdt_start to start it again.
	34	*
	35	* @dev: WDT Device
	36	* @return: 0 if OK, -ve on error
	37	*/
	38	int wdt_stop(struct udevice *dev);
	39
	40	/*
	41	* Stop all registered watchdog devices.
	42	*
	43	* @return: 0 if ok, first error encountered otherwise (but wdt_stop()
	44	* is still called on following devices)
	45	*/
	46	int wdt_stop_all(void);
	47
	48	/*
	49	* Reset the timer, typically restoring the counter to
	50	* the value configured by start()
	51	*
	52	* @dev: WDT Device
	53	* @return: 0 if OK, -ve on error
	54	*/
	55	int wdt_reset(struct udevice *dev);
	56
	57	/*
	58	* Expire the timer, thus executing its action immediately.
	59	* This is typically used to reset the board or peripherals.
	60	*
	61	* @dev: WDT Device
	62	* @flags: Driver specific flags
	63	* Return: 0 if OK -ve on error. If wdt action is system reset,
	64	* this function may never return.
	65	*/
	66	int wdt_expire_now(struct udevice *dev, ulong flags);
	67
	68	/*
	69	* struct wdt_ops - Driver model wdt operations
	70	*
	71	* The uclass interface is implemented by all wdt devices which use
	72	* driver model.
	73	*/
	74	struct wdt_ops {
	75	/*
	76	* Start the timer
	77	*
	78	* @dev: WDT Device
	79	* @timeout_ms: Number of ticks (milliseconds) before the timer expires
	80	* @flags: Driver specific flags. This might be used to specify
	81	* which action needs to be executed when the timer expires
	82	* @return: 0 if OK, -ve on error
	83	*/
	84	int (start)(struct udevice dev, u64 timeout_ms, ulong flags);
	85	/*
	86	* Stop the timer
	87	*
	88	* @dev: WDT Device
	89	* @return: 0 if OK, -ve on error
	90	*/
	91	int (stop)(struct udevice dev);
	92	/*
	93	* Reset the timer, typically restoring the counter to
	94	* the value configured by start()
	95	*
	96	* @dev: WDT Device
	97	* @return: 0 if OK, -ve on error
	98	*/
	99	int (reset)(struct udevice dev);
	100	/*
	101	* Expire the timer, thus executing the action immediately (optional)
	102	*
	103	* If this function is not provided, a default implementation
	104	* will be used, which sets the counter to 1
	105	* and waits forever. This is good enough for system level
	106	* reset, where the function is not expected to return, but might not be
	107	* good enough for other use cases.
	108	*
	109	* @dev: WDT Device
	110	* @flags: Driver specific flags
	111	* @return 0 if OK -ve on error. May not return.
	112	*/
	113	int (expire_now)(struct udevice dev, ulong flags);
	114	};
	115
	116	int initr_watchdog(void);
	117
	118	#endif /* _WDT_H_ */