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/* 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);
};
#if CONFIG_IS_ENABLED(WDT)
#ifndef CONFIG_WATCHDOG_TIMEOUT_MSECS
#define CONFIG_WATCHDOG_TIMEOUT_MSECS (60 * 1000)
#endif
#define WATCHDOG_TIMEOUT_SECS (CONFIG_WATCHDOG_TIMEOUT_MSECS / 1000)
static inline int initr_watchdog(void)
{
u32 timeout = WATCHDOG_TIMEOUT_SECS;
/*
* Init watchdog: This will call the probe function of the
* watchdog driver, enabling the use of the device
*/
if (uclass_get_device_by_seq(UCLASS_WDT, 0,
(struct udevice **)&gd->watchdog_dev)) {
debug("WDT: Not found by seq!\n");
if (uclass_get_device(UCLASS_WDT, 0,
(struct udevice **)&gd->watchdog_dev)) {
printf("WDT: Not found!\n");
return 0;
}
}
if (CONFIG_IS_ENABLED(OF_CONTROL)) {
timeout = dev_read_u32_default(gd->watchdog_dev, "timeout-sec",
WATCHDOG_TIMEOUT_SECS);
}
wdt_start(gd->watchdog_dev, timeout * 1000, 0);
gd->flags |= GD_FLG_WDT_READY;
printf("WDT: Started with%s servicing (%ds timeout)\n",
IS_ENABLED(CONFIG_WATCHDOG) ? "" : "out", timeout);
return 0;
}
#endif
#endif /* _WDT_H_ */
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