rockbox/firmware/export/bootdata.h

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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
*
* Copyright (C) 2017 by Amaury Pouly
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef __RB_BOOTDATA__
#define __RB_BOOTDATA__
#ifndef __ASSEMBLER__
#include <stdint.h>
#endif
/* /!\ This file can be included in assembly files /!\ */
/** The boot data will be filled by the bootloader with information that might
* be relevant for Rockbox. The bootloader will search for the structure using
* the magic header within the first BOOT_DATA_SEARCH_SIZE bytes of the binary.
* Typically, this structure should be as close as possible to the entry point */
/* Search size for the data structure after entry point */
#define BOOT_DATA_SEARCH_SIZE 1024
#define BOOT_DATA_MAGIC0 ('r' | 'b' << 8 | 'm' << 16 | 'a' << 24)
#define BOOT_DATA_MAGIC1 ('g' | 'i' << 8 | 'c' << 16 | '!' << 24)
/* maximum size of payload */
#define BOOT_DATA_PAYLOAD_SIZE 4
#ifndef __ASSEMBLER__
/* This is the C structure */
struct boot_data_t
{
union
{
uint32_t crc; /* crc of payload data (CRC32 with 0xffffffff for initial value) */
uint32_t magic[2]; /* BOOT_DATA_MAGIC0/1 */
};
uint32_t length; /* length of the payload */
/* add fields here */
union
{
struct
{
uint8_t boot_volume;
};
uint8_t payload[BOOT_DATA_PAYLOAD_SIZE];
};
} __attribute__((packed));
#if !defined(BOOTLOADER)
extern struct boot_data_t boot_data;
#endif
#else /* __ASSEMBLER__ */
/* This assembler macro implements an empty boot structure with just the magic
* string */
.macro put_boot_data_here
.global boot_data
boot_data:
.word BOOT_DATA_MAGIC0
.word BOOT_DATA_MAGIC1
.word BOOT_DATA_PAYLOAD_SIZE
.space BOOT_DATA_PAYLOAD_SIZE, 0xff /* payload, initialised with value 0xff */
.endm
#endif
#endif /* __RB_BOOTDATA__ */