[PATCH] fpga zynq: Check the bitstream for validity

[jgunthorpe@obsidianresearch.com (Jason Gunthorpe)]

On Fri, Oct 28, 2016 at 05:09:26PM -0700, Moritz Fischer wrote:
> It's not a single command but rather a sequence of steps we take to
> create an image that works (using write_cfgmem instead of write_binfile)

Ah, and it relies on newer Vivado features too.. Never had a use for
write_cfgmem before, and wouldn't have thought it did this.

I always do these transform externally and we tack our own header onto
the bitfile as well..

> > So, the question still remains, should the driver require the header
> > be stripped (eg the sync word is the first 4 bytes), or should it
> > search the first bit for an aligned sync word?
> 
> So currently we don't require it to be stripped, changing it so it does
> require stripping would break people's setups that already use the
> current implementation.

Considering there is a way to produce an acceptable bitfile via
write_cfgmem I think we should stick with that and allow the header to
be present, otherwise all users need yet another tool.

I'll send another patch when I get back from the plumbers conference.

> > Either requirement is acceptable to the hardware. My patch does the
> > former, I suspect you need the later?
> 
> For my usecases I could deal with either way, looking at backwards
> compat the latter one would be preferential I supose ...

Well, there are no in-kernel users, and no uapi, so it isn't such a
big deal. I'm actually surprised this got merged without users ..

Jason