include/android_image.h

/* SPDX-License-Identifier: BSD-3-Clause */
/*
 * This is from the Android Project,
 * Repository: https://android.googlesource.com/platform/system/tools/mkbootimg
 * File: include/bootimg/bootimg.h
 * Commit: e55998a0f2b61b685d5eb4a486ca3a0c680b1a2f
 *
 * Copyright (C) 2007 The Android Open Source Project
 */

#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
#define ANDR_BOOT_EXTRA_ARGS_SIZE 1024

/*
 * It is expected that callers would explicitly specify which version of the
 * boot image header they need to use.
 */
typedef struct andr_img_hdr andr_img_hdr;

/* The bootloader expects the structure of andr_img_hdr with header
 * version 0 to be as follows: */
struct andr_img_hdr {
    /* Must be ANDR_BOOT_MAGIC. */
    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 */

    /* Version of the boot image header. */
    u32 header_version;

    /* Operating system version and security patch level.
     * For version "A.B.C" and patch level "Y-M-D":
     *   (7 bits for each of A, B, C; 7 bits for (Y-2000), 4 bits for M)
     *   os_version = A[31:25] B[24:18] C[17:11] (Y-2000)[10:4] M[3:0] */
    u32 os_version;

    char name[ANDR_BOOT_NAME_SIZE]; /* asciiz product name */

    char cmdline[ANDR_BOOT_ARGS_SIZE];

    u32 id[8]; /* timestamp / checksum / sha1 / etc */

    /* Supplemental command line data; kept here to maintain
     * binary compatibility with older versions of mkbootimg. */
    char extra_cmdline[ANDR_BOOT_EXTRA_ARGS_SIZE];

    /* Fields in boot_img_hdr_v1 and newer. */
    u32 recovery_dtbo_size;   /* size in bytes for recovery DTBO/ACPIO image */
    u64 recovery_dtbo_offset; /* offset to recovery dtbo/acpio in boot image */
    u32 header_size;

    /* Fields in boot_img_hdr_v2 and newer. */
    u32 dtb_size; /* size in bytes for DTB image */
    u64 dtb_addr; /* physical load address for DTB image */
} __attribute__((packed));

/* When a boot header is of version 0, the structure of boot image is as
 * follows:
 *
 * +-----------------+
 * | 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
 */

/* When the boot image header has a version of 2, the structure of the boot
 * image is as follows:
 *
 * +---------------------+
 * | boot header         | 1 page
 * +---------------------+
 * | kernel              | n pages
 * +---------------------+
 * | ramdisk             | m pages
 * +---------------------+
 * | second stage        | o pages
 * +---------------------+
 * | recovery dtbo/acpio | p pages
 * +---------------------+
 * | dtb                 | q 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
 * p = (recovery_dtbo_size + page_size - 1) / page_size
 * q = (dtb_size + page_size - 1) / page_size
 *
 * 0. all entities are page_size aligned in flash
 * 1. kernel, ramdisk and DTB are required (size != 0)
 * 2. recovery_dtbo/recovery_acpio is required for recovery.img in non-A/B
 *    devices(recovery_dtbo_size != 0)
 * 3. second is optional (second_size == 0 -> no second)
 * 4. load each element (kernel, ramdisk, second, dtb) at
 *    the specified physical address (kernel_addr, etc)
 * 5. If booting to recovery mode in a non-A/B device, extract recovery
 *    dtbo/acpio and apply the correct set of overlays on the base device tree
 *    depending on the hardware/product revision.
 * 6. prepare tags at tag_addr.  kernel_args[] is
 *    appended to the kernel commandline in the tags.
 * 7. r0 = 0, r1 = MACHINE_TYPE, r2 = tags_addr
 * 8. if second_size != 0: jump to second_addr
 *    else: jump to kernel_addr
 */

#endif