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https://github.com/Rockbox/rockbox.git
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6ffd42548b
Instead of verifying the CRC before every access of the boot data, verify the CRC once at startup and set a flag to indicate the boot data is valid. Also add a framework to support multiple boot protocol versions. Firmware declares the maximum supported protocol version using a version byte in the boot data header. The bootloader chooses the highest version supported by it and the firmware when deciding what boot protocol to use. Change-Id: I810194625dc0833f026d2a23b8d64ed467fa6aca
92 lines
2.9 KiB
C
92 lines
2.9 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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*
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* Copyright (C) 2017 by Amaury Pouly
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#ifndef __RB_BOOTDATA__
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#define __RB_BOOTDATA__
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#ifndef __ASSEMBLER__
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#include <stdint.h>
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#include "system.h"
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#endif
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/* /!\ This file can be included in assembly files /!\ */
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/** The boot data will be filled by the bootloader with information that might
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* be relevant for Rockbox. The bootloader will search for the structure using
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* the magic header within the first BOOT_DATA_SEARCH_SIZE bytes of the binary.
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* Typically, this structure should be as close as possible to the entry point */
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/* Search size for the data structure after entry point */
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#define BOOT_DATA_SEARCH_SIZE 1024
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#define BOOT_DATA_MAGIC0 ('r' | 'b' << 8 | 'm' << 16 | 'a' << 24)
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#define BOOT_DATA_MAGIC1 ('g' | 'i' << 8 | 'c' << 16 | '!' << 24)
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#define BOOT_DATA_VERSION 0
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/* maximum size of payload */
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#define BOOT_DATA_PAYLOAD_SIZE 4
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#ifndef __ASSEMBLER__
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/* This is the C structure */
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struct boot_data_t
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{
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union
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{
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uint32_t crc; /* crc of payload data (CRC32 with 0xffffffff for initial value) */
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uint32_t magic[2]; /* BOOT_DATA_MAGIC0/1 */
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};
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uint32_t length; /* length of the payload */
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/* add fields here */
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union
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{
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struct
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{
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uint8_t boot_volume;
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uint8_t version;
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};
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uint8_t payload[BOOT_DATA_PAYLOAD_SIZE];
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};
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} __attribute__((packed));
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#if !defined(BOOTLOADER)
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extern struct boot_data_t boot_data;
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extern bool boot_data_valid;
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void verify_boot_data(void) INIT_ATTR;
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#endif
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#else /* __ASSEMBLER__ */
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/* This assembler macro implements an empty boot structure with just the magic
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* string */
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.macro put_boot_data_here
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.global boot_data
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boot_data:
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.word BOOT_DATA_MAGIC0
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.word BOOT_DATA_MAGIC1
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.word BOOT_DATA_PAYLOAD_SIZE
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.byte 0xff /* boot volume */
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.byte BOOT_DATA_VERSION /* maximum supported boot protocol version */
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.space (BOOT_DATA_PAYLOAD_SIZE - 2), 0xff /* remainder of payload */
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.endm
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#endif
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#endif /* __RB_BOOTDATA__ */
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