[PATCH] mx8m: csf.sh: pad csf blob for u-boot.itb to CSF_SIZE minus IVT header

[Marek Vasut]

On 9/19/23 21:15, Rasmus Villemoes wrote:
> On 19/09/2023 20.27, Marek Vasut wrote:
>> On 9/19/23 12:00, Rasmus Villemoes wrote:
>>> When built with CONFIG_IMX_HAB, the full FIT image, including stuff
>>> tacked on beyond the end of the fdt structure, is expected to be (fdt
>>> size rounded up to 0x1000 boundary)+CONFIG_CSF_SIZE.
>>>
>>> Now, when the FIT image is loaded from a storage device, it doesn't
>>> really matter that the flash.bin that gets written to target isn't
>>> quite that big - we will just load some garbage bytes that are never
>>> read or used for anything. But when flash.bin is uploaded via uuu,
>>> it's important that we actually serve at least as many bytes as the
>>> target expects, or we will hang in rom_api_download_image().
>>>
>>> Extend the logic in the csf.sh script so that the csf blob is padded
>>> to CONFIG_CSF_SIZE minus the size of the IVT header.
>>
>> On which SoC do you trigger this stuff ?
> 
> imx8mp
> 
>> (or rather, which bootrom version, v1 or v2? they each use SDP or SDPS
>> respectively)
> 
> Absolutely no idea. I just do "uuu flash.bin", which seems to DTRT
> automatically, I've never figured out the esoteric uuu language, and
> I've never found any actual documentation for it.

So yeah, MX8MP is SDPS (streaming).

> It also doesn't work without
> https://lore.kernel.org/u-boot/20230919134932.134678-1-rasmus.villemoes@prevas.dk/
> due to the spl_load_simple_fit() abuse.
> 
>>> +
>>> +# When loading flash.bin via USB, we must ensure that the file being
>>> +# served is as large as the target expects (see
>>> +# board_spl_fit_size_align()), otherwise the target will hang in
>>> +# rom_api_download_image() waiting for the remaining bytes.
>>> +CSF_SIZE=$(sed -n "/CONFIG_CSF_SIZE=/ s at .*=@@p" .config)
>>> +truncate -s $((CSF_SIZE - 0x20)) csf_fit.bin
>>
>> Can you use dd(1) instead ? I think dd(1) is more portable than
>> truncate(1) , at least I cannot find truncate(1) in opengroup specs.
> 
> Certainly.

Please do v2 with dd and then we should be all fine, thanks.