Re: [RFC PATCH v2 0/1] FPGA subsystem core

From: H. Peter Anvin
Date: Fri Oct 04 2013 - 14:13:25 EST


On 10/04/2013 10:44 AM, Michal Simek wrote:
>
> If you look at it in general I believe that there is wide range of
> applications which just contain one bitstream per fpga and the
> bitstream is replaced by newer version in upgrade. For them
> firmware interface should be pretty useful. Just setup firmware
> name with bitstream and it will be automatically loaded in startup
> phase.
>
> Then there is another set of applications especially in connection
> to partial reconfiguration where this can be done statically by
> pregenerated partial bitstreams or automatically generated on
> target cpu. For doing everything on the target firmware interface
> is not the best because everything can be handled by user
> application and it is easier just to push this bitstream to do
> device and not to save it to the fs.
>
> I think the question here is if this subsystem could have several
> interfaces. For example Alan is asking for adding char support.
> Does it even make sense to have more interfaces with the same
> backend driver? When this is answered then we can talk which one
> make sense to have. In v2 is sysfs and firmware one. Adding char
> is also easy to do.
>

Greg, what do you think?

I agree that the firmware interface makes sense when the use of the
FPGA is an implementation detail in a fixed hardware configuration,
but that is a fairly restricted use case all things considered.

-hpa

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