[U-Boot] [PATCH v2] arm64: allow space reservation for boot header

[Steve Rae]

Hi,

On Wed, May 25, 2016 at 1:48 AM, Hans de Goede <hdegoede at redhat.com> wrote:

> Hi,
>
> On 25-05-16 10:40, Andre Przywara wrote:
>
>> Some SPL loaders (like Allwinner's boot0) require a header before the
>> actual U-Boot binary to both check its validity and to find other data
>> to load.
>> Introduce a config option to reserve some space at the beginning of the
>> binary to later hold the header if needed.
>> Please note that the current arm64 start.S jumps over some portion of
>> data already, so this option bascially just increases this region
>> to allow post-processing tools to insert more data there.
>> This also means that both filling the header is optional and also having
>> some extra space in there does not hurt apart from enlarging the binary.
>>
>> For the use with Allwinner's boot0 blob there is a tool called
>> boot0img[1], which fills the header to allow booting A64 based boards.
>> For the Pine64 we need a 1536 Byte header (including the branch
>> instruction) at the moment, so we add this to the defconfig.
>>
>> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
>>
>> [1] https://github.com/apritzel/pine64/tree/master/tools
>>
>
> v2 looks good to me:
>
> Acked-by: Hans de Goede <hdegoede at redhat.com>
>
> Tom, can you pick this one up please (I'm asking you since it is
> touching some non sunxi files) ?
>
> Regards,
>
> Hans
>
>
>
> ---
>>  arch/arm/cpu/armv8/start.S    | 3 +++
>>  board/sunxi/Kconfig           | 7 +++++++
>>  configs/pine64_plus_defconfig | 1 +
>>  include/configs/sun50i.h      | 4 ++++
>>  4 files changed, 15 insertions(+)
>>
>> diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S
>> index e933021..a9cd7e9 100644
>> --- a/arch/arm/cpu/armv8/start.S
>> +++ b/arch/arm/cpu/armv8/start.S
>> @@ -21,6 +21,9 @@
>>  _start:
>>         b       reset
>>
>> +#ifdef CONFIG_START_HEADER_SPACE
>> +       .space CONFIG_START_HEADER_SPACE /* can be filled with a boot0
>> header */
>> +#endif
>>         .align 3
>>
>>
Just wondering, is there any way to make this even more generic?
In your case, you are wanting
        .space 1532
But in my case I am actually wanting something like:
        .word   0x12345678
        .word   _end - _start
Thanks, Steve

 .globl _TEXT_BASE
>> diff --git a/board/sunxi/Kconfig b/board/sunxi/Kconfig
>> index fa78720..9f2e17e 100644
>> --- a/board/sunxi/Kconfig
>> +++ b/board/sunxi/Kconfig
>> @@ -15,6 +15,13 @@ config SUNXI_GEN_SUN6I
>>         separate ahb reset control registers, custom pmic bus, new style
>>         watchdog, etc.
>>
>> +config SUNXI_BOOT0
>> +       bool "prepare for boot0 header"
>> +       ---help---
>> +       If U-Boot is loaded from the Allwinner provided boot0 blob, it
>> +       expects a header area filled with magic values.
>> +       This option will add some space at the beginning of the image to
>> +       let a tool later on fill in this header with sensible data.
>>
>>  choice
>>         prompt "Sunxi SoC Variant"
>> diff --git a/configs/pine64_plus_defconfig b/configs/pine64_plus_defconfig
>> index 0977334..b93e4da 100644
>> --- a/configs/pine64_plus_defconfig
>> +++ b/configs/pine64_plus_defconfig
>> @@ -18,3 +18,4 @@ CONFIG_CMD_EXT2=y
>>  CONFIG_CMD_EXT4=y
>>  CONFIG_CMD_FAT=y
>>  CONFIG_CMD_FS_GENERIC=y
>> +CONFIG_SUNXI_BOOT0=y
>> diff --git a/include/configs/sun50i.h b/include/configs/sun50i.h
>> index 0fdb4c7..6923b60 100644
>> --- a/include/configs/sun50i.h
>> +++ b/include/configs/sun50i.h
>> @@ -17,6 +17,10 @@
>>  #define GICD_BASE              0x1c81000
>>  #define GICC_BASE              0x1c82000
>>
>> +#ifdef CONFIG_SUNXI_BOOT0
>> +#define CONFIG_START_HEADER_SPACE      1532
>> +#endif
>> +
>>  /*
>>   * Include common sunxi configuration where most the settings are
>>   */
>>
>>