avionic design with actual uboot and tooling

submodule of avionic design uboot bootloader and with included tools to
get you started , read readme.md and readme-tk1-loader.md

u-boot/include/bootretry.h

@@ -0,0 +1,59 @@
+/*
+ * (C) Copyright 2000
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __BOOTRETRY_H
+#define __BOOTRETRY_H
+
+#ifdef CONFIG_BOOT_RETRY_TIME
+/**
+ * bootretry_tstc_timeout() - ensure we get a keypress before timeout
+ *
+ * Check for a keypress repeatedly, resetting the watchdog each time. If a
+ * keypress is not received within the command timeout, return an error.
+ *
+ * @return 0 if a key is received in time, -ETIMEDOUT if not
+ */
+int bootretry_tstc_timeout(void);
+
+/**
+ * bootretry_init_cmd_timeout() - set up command timeout
+ *
+ * Get the required command timeout from the environment.
+ */
+void bootretry_init_cmd_timeout(void);
+
+/**
+ * bootretry_reset_cmd_timeout() - reset command timeout
+ *
+ * Reset the command timeout so that the user has a fresh start. This is
+ * typically used when input is received from the user.
+ */
+void bootretry_reset_cmd_timeout(void);
+
+/** bootretry_dont_retry() - Indicate that we should not retry the boot */
+void bootretry_dont_retry(void);
+#else
+static inline int bootretry_tstc_timeout(void)
+{
+	return 0;
+}
+
+static inline void bootretry_init_cmd_timeout(void)
+{
+}
+
+static inline void bootretry_reset_cmd_timeout(void)
+{
+}
+
+static inline void bootretry_dont_retry(void)
+{
+}
+
+#endif
+
+#endif