[PATCH] fpga zynq: Check the bitstream for validity

[Michal Simek]

Hi Jason,

On 31.10.2016 17:23, Jason Gunthorpe wrote:
> 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 ..

There were several things in this whole thread.

Regarding BIT and BIN format. This support is in vivado for a long time
and it is up2you what you want to support. We have removed that BIT
support and not doing any swap by saying only BIN format is supported.

If driver check header and if it is not valid you should just error out.
If header is fine driver can program it.

Regarding what you need to do in Vivado to get your bitstream right is
completely out of this thread and TBH I don't know it too.

Thanks,
Michal