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/android_image.h

@@ -0,0 +1,69 @@
+/*
+ * This is from the Android Project,
+ * Repository: https://android.googlesource.com/platform/bootable/bootloader/legacy
+ * File: include/boot/bootimg.h
+ * Commit: 4205b865141ff2e255fe1d3bd16de18e217ef06a
+ *
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#ifndef _ANDROID_IMAGE_H_
+#define _ANDROID_IMAGE_H_
+
+#define ANDR_BOOT_MAGIC "ANDROID!"
+#define ANDR_BOOT_MAGIC_SIZE 8
+#define ANDR_BOOT_NAME_SIZE 16
+#define ANDR_BOOT_ARGS_SIZE 512
+
+struct andr_img_hdr {
+	char magic[ANDR_BOOT_MAGIC_SIZE];
+
+	u32 kernel_size;	/* size in bytes */
+	u32 kernel_addr;	/* physical load addr */
+
+	u32 ramdisk_size;	/* size in bytes */
+	u32 ramdisk_addr;	/* physical load addr */
+
+	u32 second_size;	/* size in bytes */
+	u32 second_addr;	/* physical load addr */
+
+	u32 tags_addr;		/* physical addr for kernel tags */
+	u32 page_size;		/* flash page size we assume */
+	u32 unused[2];		/* future expansion: should be 0 */
+
+	char name[ANDR_BOOT_NAME_SIZE]; /* asciiz product name */
+
+	char cmdline[ANDR_BOOT_ARGS_SIZE];
+
+	u32 id[8]; /* timestamp / checksum / sha1 / etc */
+};
+
+/*
+ * +-----------------+
+ * | boot header     | 1 page
+ * +-----------------+
+ * | kernel          | n pages
+ * +-----------------+
+ * | ramdisk         | m pages
+ * +-----------------+
+ * | second stage    | o pages
+ * +-----------------+
+ *
+ * n = (kernel_size + page_size - 1) / page_size
+ * m = (ramdisk_size + page_size - 1) / page_size
+ * o = (second_size + page_size - 1) / page_size
+ *
+ * 0. all entities are page_size aligned in flash
+ * 1. kernel and ramdisk are required (size != 0)
+ * 2. second is optional (second_size == 0 -> no second)
+ * 3. load each element (kernel, ramdisk, second) at
+ *    the specified physical address (kernel_addr, etc)
+ * 4. prepare tags at tag_addr.  kernel_args[] is
+ *    appended to the kernel commandline in the tags.
+ * 5. r0 = 0, r1 = MACHINE_TYPE, r2 = tags_addr
+ * 6. if second_size != 0: jump to second_addr
+ *    else: jump to kernel_addr
+ */
+#endif