[U-Boot] Questions on adding a new type to mkimage

[Simon Glass]

Hi Charles,


On 20 February 2014 12:50, Charles Manning <cdhmanning at gmail.com> wrote:
>
> I am in the throes of extending mkimage to add socfpga support. This is my
> first time in mkimage, so please forgive me being on a learning curve.
>
> It seems that the most "normal" path for mkimage signers is to append some
> sort of header to the front of the image
> ie the flow is
>
> write header out
> copy image data with copy_file
> call set_header
>
> The socfpga preloader needs something a bit different. It does not add a
> header, but instead adds a tail (CRC+padding) and mashes some bytes into a
> known place in the image.
>
> Unfortunately the mkimage framework does not seem to provide an "add tail"
> function which is really what is needed here.
>
> The only way I can see to extend the size of the image, using the normal
> mkimage workflow would be to do something like this:
>
> *Provide vrec_header which adds a fake header of 64k - input_size.
> * Allow copy_file to then do the copy step.
> * I now have a 64k "image" which is 64k-size 0 bytes, followed by the actual
> input_data.
> * When set_header is called, shift the actual input data to where it should
> be, add the CRC and fix up the padding.
>
> This seems needlessly contrived to work with the framework.


There is the rather off fflag_handle() function - could you make use of that?

>
> Or the alternative might be just to treat this as a special case....
>
> Thoughts/opinions???


I don't see a problem with adding to the framework if needed.

Regards,
Simon