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Diffstat (limited to 'include/wdt.h')
| -rw-r--r-- | include/wdt.h | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/include/wdt.h b/include/wdt.h new file mode 100644 index 0000000..5bcff24 --- /dev/null +++ b/include/wdt.h @@ -0,0 +1,147 @@ +/* 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_ */ |