u-boot/include/wdt.h
Tom Rini 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00

106 lines
3 KiB
C

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