mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-10 15:14:43 +00:00
0753bc2d30
This is a simple uclass for Watchdog Timers. It has four operations: start, restart, reset, stop. Drivers must implement start, restart and stop operations, while implementing reset is optional: It's default implementation expires watchdog timer in one clock tick. Signed-off-by: Maxim Sloyko <maxims@google.com> Reviewed-by: Simon Glass <sjg@chromium.org>
107 lines
3 KiB
C
107 lines
3 KiB
C
/*
|
|
* 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: Number of ticks 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, 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: Number of ticks 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, 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_ */
|