148 lines
4.0 KiB
C
148 lines
4.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* Copyright 2017 Google, Inc
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*/
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#ifndef _WDT_H_
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#define _WDT_H_
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#include <dm.h>
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#include <dm/read.h>
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/*
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* Implement a simple watchdog uclass. Watchdog is basically a timer that
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* is used to detect or recover from malfunction. During normal operation
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* the watchdog would be regularly reset to prevent it from timing out.
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* If, due to a hardware fault or program error, the computer fails to reset
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* the watchdog, the timer will elapse and generate a timeout signal.
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* The timeout signal is used to initiate corrective action or actions,
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* which typically include placing the system in a safe, known state.
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*/
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/*
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* Start the timer
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*
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* @dev: WDT Device
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* @timeout_ms: Number of ticks (milliseconds) before timer expires
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* @flags: Driver specific flags. This might be used to specify
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* which action needs to be executed when the timer expires
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* @return: 0 if OK, -ve on error
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*/
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int wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags);
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/*
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* Stop the timer, thus disabling the Watchdog. Use wdt_start to start it again.
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*
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* @dev: WDT Device
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* @return: 0 if OK, -ve on error
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*/
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int wdt_stop(struct udevice *dev);
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/*
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* Reset the timer, typically restoring the counter to
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* the value configured by start()
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*
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* @dev: WDT Device
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* @return: 0 if OK, -ve on error
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*/
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int wdt_reset(struct udevice *dev);
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/*
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* Expire the timer, thus executing its action immediately.
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* This is typically used to reset the board or peripherals.
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*
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* @dev: WDT Device
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* @flags: Driver specific flags
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* @return 0 if OK -ve on error. If wdt action is system reset,
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* this function may never return.
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*/
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int wdt_expire_now(struct udevice *dev, ulong flags);
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/*
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* struct wdt_ops - Driver model wdt operations
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*
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* The uclass interface is implemented by all wdt devices which use
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* driver model.
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*/
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struct wdt_ops {
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/*
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* Start the timer
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*
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* @dev: WDT Device
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* @timeout_ms: Number of ticks (milliseconds) before the timer expires
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* @flags: Driver specific flags. This might be used to specify
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* which action needs to be executed when the timer expires
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* @return: 0 if OK, -ve on error
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*/
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int (*start)(struct udevice *dev, u64 timeout_ms, ulong flags);
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/*
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* Stop the timer
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*
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* @dev: WDT Device
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* @return: 0 if OK, -ve on error
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*/
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int (*stop)(struct udevice *dev);
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/*
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* Reset the timer, typically restoring the counter to
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* the value configured by start()
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*
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* @dev: WDT Device
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* @return: 0 if OK, -ve on error
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*/
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int (*reset)(struct udevice *dev);
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/*
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* Expire the timer, thus executing the action immediately (optional)
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*
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* If this function is not provided, a default implementation
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* will be used, which sets the counter to 1
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* and waits forever. This is good enough for system level
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* reset, where the function is not expected to return, but might not be
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* good enough for other use cases.
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*
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* @dev: WDT Device
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* @flags: Driver specific flags
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* @return 0 if OK -ve on error. May not return.
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*/
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int (*expire_now)(struct udevice *dev, ulong flags);
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};
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#if defined(CONFIG_WDT)
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#ifndef CONFIG_WATCHDOG_TIMEOUT_MSECS
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#define CONFIG_WATCHDOG_TIMEOUT_MSECS (60 * 1000)
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#endif
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#define WATCHDOG_TIMEOUT_SECS (CONFIG_WATCHDOG_TIMEOUT_MSECS / 1000)
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static inline int initr_watchdog(void)
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{
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u32 timeout = WATCHDOG_TIMEOUT_SECS;
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/*
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* Init watchdog: This will call the probe function of the
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* watchdog driver, enabling the use of the device
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*/
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if (uclass_get_device_by_seq(UCLASS_WDT, 0,
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(struct udevice **)&gd->watchdog_dev)) {
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debug("WDT: Not found by seq!\n");
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if (uclass_get_device(UCLASS_WDT, 0,
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(struct udevice **)&gd->watchdog_dev)) {
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printf("WDT: Not found!\n");
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return 0;
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}
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}
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if (CONFIG_IS_ENABLED(OF_CONTROL)) {
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timeout = dev_read_u32_default(gd->watchdog_dev, "timeout-sec",
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WATCHDOG_TIMEOUT_SECS);
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}
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wdt_start(gd->watchdog_dev, timeout * 1000, 0);
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gd->flags |= GD_FLG_WDT_READY;
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printf("WDT: Started with%s servicing (%ds timeout)\n",
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IS_ENABLED(CONFIG_WATCHDOG) ? "" : "out", timeout);
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return 0;
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}
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#endif
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#endif /* _WDT_H_ */
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