diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/dm/uclass-id.h | 1 | ||||
| -rw-r--r-- | include/wdt.h | 107 |
2 files changed, 108 insertions, 0 deletions
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h index 1b635e4..4e7cc93 100644 --- a/include/dm/uclass-id.h +++ b/include/dm/uclass-id.h @@ -84,6 +84,7 @@ enum uclass_id { UCLASS_VIDEO, /* Video or LCD device */ UCLASS_VIDEO_BRIDGE, /* Video bridge, e.g. DisplayPort to LVDS */ UCLASS_VIDEO_CONSOLE, /* Text console driver for video device */ + UCLASS_WDT, /* Watchdot Timer driver */ UCLASS_COUNT, UCLASS_INVALID = -1, diff --git a/include/wdt.h b/include/wdt.h new file mode 100644 index 0000000..0b5f058 --- /dev/null +++ b/include/wdt.h @@ -0,0 +1,107 @@ +/* + * 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_ */ |