[U-Boot] [PATCH v3 7/8] imximage: Add MX53 boot image support

[Stefano Babic]

On 12/31/2010 10:25 AM, Jason Liu wrote:
> Hi, Wolfgang,
> 
> 2010/12/31 Wolfgang Denk <wd at denx.de>:
>> Dear Jason Liu,
>>
>> In message <AANLkTik1uxZK+7LL6cHtQ465Z4x+pm-kfQeaLi=D7-9S at mail.gmail.com> you wrote:
>>>
>>>> This looks as if you added something to the standard 64 byte image
>>>> header. You must not modify this. It is fixed for all architectures
>>>> and cannot be extended.
>>>
>>> This change is specific for I.MX chip and will not affect other architectur> es.
>>
>> All architectures use exactly the same binary image header.  This
>> header has no version field, and such a field cannot be added.
> 
> Here, the imx header is the data structure we defined in imximage.c
> and it will be used to generate
> the boot-able image u-boot.imx of i.mx soc together with u-boot.bin by
> .set_header function call of struct
> image_type_params according to FSLi.MX boot ROM requirement.

Yes, the field is inside the imx header and not in the 64 byte structure.

> 
> When run the command "mkimage -l u-boot.imx", the imx header will be
> fetched from the u-boot.imx and
> the version information will be decoded according to data structure
> definition, and then it do the verify by
> checking some magic number or tag according to different version, and
> in the end, it will print the header
> information if it pass the verification.
> 
> So, I don't think it will affect other architectures.

Yes, but we rely on a single undocumented byte when on the other hand
Freescale has provided at least two well-documented magic numbers for
each version to detect if an image is valid or not. Ans as I stated,
introducing this version field generates an unneeded incompatibility
with atual images.

Best regards,
Stefano Babic

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