u-boot/arch/arm/include/asm/arch-sunxi/spl.h
Siarhei Siamashka b19236fd1c sunxi: Increase SPL header size to 64 bytes to avoid code corruption
The current SPL header, created by the 'mksunxiboot' tool, has size
32 bytes. But the code in the boot ROM stores the information about
the boot media at the offset 0x28 before passing control to the SPL.
For example, when booting from the SD card, the magic number written
by the boot ROM is 0. And when booting from the SPI flash, the magic
number is 3. NAND and eMMC probably have their own special magic
numbers too.

Currently the corrupted byte is a part of one of the instructions in
the reset vectors table:

    b     reset
    ldr   pc, _undefined_instruction
    ldr   pc, _software_interrupt      <- Corruption happens here
    ldr   pc, _prefetch_abort
    ldr   pc, _data_abort
    ldr   pc, _not_used
    ldr   pc, _irq
    ldr   pc, _fiq

In practice this does not cause any visible problems, but it's still
better to fix it. As a bonus, the reported boot media type can be
later used in the 'spl_boot_device' function, but this is out of
the scope of this patch.

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
2016-05-25 17:52:39 +02:00

59 lines
1.9 KiB
C

/*
* (C) Copyright 2007-2011
* Allwinner Technology Co., Ltd. <www.allwinnertech.com>
* Tom Cubie <tangliang@allwinnertech.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#ifndef _ASM_ARCH_SPL_H_
#define _ASM_ARCH_SPL_H_
#define BOOT0_MAGIC "eGON.BT0"
#define SPL_SIGNATURE "SPL" /* marks "sunxi" SPL header */
#define SPL_HEADER_VERSION 1
#if defined(CONFIG_MACH_SUN9I) || defined(CONFIG_MACH_SUN50I)
#define SPL_ADDR 0x10000
#else
#define SPL_ADDR 0x0
#endif
/* The low 8-bits of the 'boot_media' field in the SPL header */
#define SUNXI_BOOTED_FROM_MMC0 0
#define SUNXI_BOOTED_FROM_SPI 3
/* boot head definition from sun4i boot code */
struct boot_file_head {
uint32_t b_instruction; /* one intruction jumping to real code */
uint8_t magic[8]; /* ="eGON.BT0" or "eGON.BT1", not C-style str */
uint32_t check_sum; /* generated by PC */
uint32_t length; /* generated by PC */
/*
* We use a simplified header, only filling in what is needed
* by the boot ROM. To be compatible with Allwinner tools we
* would need to implement the proper fields here instead of
* padding.
*
* Actually we want the ability to recognize our "sunxi" variant
* of the SPL. To do so, let's place a special signature into the
* "pub_head_size" field. We can reasonably expect Allwinner's
* boot0 to always have the upper 16 bits of this set to 0 (after
* all the value shouldn't be larger than the limit imposed by
* SRAM size).
* If the signature is present (at 0x14), then we know it's safe
* to use the remaining 8 bytes (at 0x18) for our own purposes.
* (E.g. sunxi-tools "fel" utility can pass information there.)
*/
union {
uint32_t pub_head_size;
uint8_t spl_signature[4];
};
uint32_t fel_script_address;
uint32_t reserved1[3];
uint32_t boot_media; /* written here by the boot ROM */
uint32_t reserved2[5]; /* padding, align to 64 bytes */
};
#define is_boot0_magic(addr) (memcmp((void *)addr, BOOT0_MAGIC, 8) == 0)
#endif