GK SDK 源码库: XMIPCLinuxV100R005C00SPC030 (kernel/tools/open_source excluded)

2026-09-06 03:52:57 +08:00
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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_ */