[U-Boot] [PATCH 1/2] fit: Support FDT compression

[Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>]

On 18.04.19 22:36, Julius Werner wrote:
>> My approach was to uncompress all compressed images on-the-fly in
>> fit_image_load().
> 
> Right, that's essentially what this patch is doing too.

Cool. I'm sorry I haven't found the time to dig into your patch for 
details (too much day-to-day work right now).

> 
>> Or I could dig up my patches from October and we'll see how far you get
>> with those?
> 
> I think I found your patch:
> https://lists.denx.de/pipermail/u-boot/2018-October/344673.html

Exactly. I do have some further versions locally, but no real 
breakthrough I think.

> It seems to be doing something very close to what my patch does
> anyway. My patch goes a little further by also solving the case when
> no load address is given (in that case it will malloc() a buffer to
> decompress into with an upper bound guess for the required size).

Hmm, I think we might want to use the lmb functions here to allocate a 
buffer instead of relyling on malloc? The malloc pool might be large 
enough for an uncompressed devicetree, but not for an 8 MByte FPGA image...

But starting with malloc might be ok.

> If there is a load size given, the two should end up doing the same
> thing. Also your patch works on all image types, which as you said
> there breaks it for kernels. I think the option of doing it for all
> image types except kernels would be a good solution for everyone.
> (Ultimately, I think it might be nicer if the kernel decompression
> would also be handled there and not as a special case, but I'd rather
> not tackle everything at once. This can always be iterated upon in the
> future.)

The reason I discontinued that patch was that I started adding a feature 
to mkimage to add a property for the uncompressed size. This is still 
pending work I haven't sent to the ML, but I do want to continue it once 
I find the time.

So maybe we could move on with a v2 of your patch that uncompresses 
everything but the kernel? I'd like to test that with my compressed FPGA 
images then.

Regards,
Simon