Re: [RFC 7/8] fpga-region: add sysfs interface

From	matthew.gerlach@linux.intel.com
Newsgroups	linux.kernel
Subject	Re: [RFC 7/8] fpga-region: add sysfs interface
Date	2017-02-28 07:30 +0100
Message-ID	<tfJsl-zM-3@gated-at.bofh.it> (permalink)
References	(10 earlier) <tcIVP-5aM-9@gated-at.bofh.it> <td626-2RA-13@gated-at.bofh.it> <tdnvY-6me-25@gated-at.bofh.it> <tfCqS-3Po-7@gated-at.bofh.it> <tfCqR-3Po-5@gated-at.bofh.it>
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On Mon, 27 Feb 2017, Moritz Fischer wrote:

> Alan,
>
> On Mon, Feb 27, 2017 at 12:09 PM, Alan Tull <delicious.quinoa@gmail.com> wrote:
>
>
>> First case: embedded FPGA.  The hardware has one FPGA.  The image is
>> designed for a specific board, so there's no problem including the
>> enumeration in the image.
>
> Agreed.
>
>> Second case: embedded FPGA + a PCIe FPGA.  The image will be specific
>> as to whether it goes into the embedded FPGA or the PCIe one.
>
> Agreed.
>
>
>> Third case: multiple PCIe FPGAs.  The enumeration base will be the
>> PCIe bus of the individual FPGA.  If the FPGAs don't have unique pin
>> connections, then the images could go on any of the PCie FPGAs.  If
>> there are unique pin connections, then the image will be specific to
>> the FPGA and having the enumeration data in the image is that much
>> more helpful for keeping things straight.  Part of the header could
>> specify which specific FPGA it should go on if it is restricted.
>
> Agreed.
>
>> Of course if the FPGAs have > 1 PR regions, most FPGA architectures do
>> not have relocatable images so those images will be specific for the
>> PR region but not specific to the FPGA except as otherwise noted
>> above.
>>
>> So again, including enumeration data in the bitstream should work
>> unless I'm missing something.  What am I missing here?
>
> If you enumeration base is sufficiently smart, I suppose that can work.
> What you'd probably want is some sort of extension to the platform bus?

I think there is merit it considering the platform bus as part of the 
overal enumeration strategy.  When using device trees, the platform bus is 
involved.  I have also seen other folks enumerate over a platform bus 
based on data in a format other than device tree.  I have experimented 
with instantiating platform devices from my pcie driver, but I didn't 
completely work, which could be related to using a fairly old 3.10 kernel.

Matthew Gerlach

>
> I really need to take another look at how non-dt systems enumerate to
> give better feedback on this.
>
> Cheers,
>
> Moritz
> --
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Thread

[RFC 7/8] fpga-region: add sysfs interface Alan Tull <atull@kernel.org> - 2017-02-15 17:20 +0100
  Re: [RFC 7/8] fpga-region: add sysfs interface Jason Gunthorpe <jgunthorpe@obsidianresearch.com> - 2017-02-15 18:30 +0100
    Re: [RFC 7/8] fpga-region: add sysfs interface Alan Tull <delicious.quinoa@gmail.com> - 2017-02-15 18:50 +0100
      Re: [RFC 7/8] fpga-region: add sysfs interface Moritz Fischer <moritz.fischer@ettus.com> - 2017-02-15 19:00 +0100
      Re: [RFC 7/8] fpga-region: add sysfs interface Jason Gunthorpe <jgunthorpe@obsidianresearch.com> - 2017-02-15 19:10 +0100
        Re: [RFC 7/8] fpga-region: add sysfs interface Alan Tull <delicious.quinoa@gmail.com> - 2017-02-15 19:30 +0100
          Re: [RFC 7/8] fpga-region: add sysfs interface Moritz Fischer <moritz.fischer@ettus.com> - 2017-02-15 19:40 +0100
          Re: [RFC 7/8] fpga-region: add sysfs interface Jason Gunthorpe <jgunthorpe@obsidianresearch.com> - 2017-02-15 20:50 +0100
            Re: [RFC 7/8] fpga-region: add sysfs interface Alan Tull <delicious.quinoa@gmail.com> - 2017-02-16 00:00 +0100
              Re: [RFC 7/8] fpga-region: add sysfs interface Jason Gunthorpe <jgunthorpe@obsidianresearch.com> - 2017-02-16 00:10 +0100
          Re: [RFC 7/8] fpga-region: add sysfs interface matthew.gerlach@linux.intel.com - 2017-02-15 21:10 +0100
            Re: [RFC 7/8] fpga-region: add sysfs interface Jason Gunthorpe <jgunthorpe@obsidianresearch.com> - 2017-02-15 21:40 +0100
              Re: [RFC 7/8] fpga-region: add sysfs interface Moritz Fischer <moritz.fischer@ettus.com> - 2017-02-15 22:00 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Jason Gunthorpe <jgunthorpe@obsidianresearch.com> - 2017-02-15 22:20 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Moritz Fischer <moritz.fischer@ettus.com> - 2017-02-15 22:40 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Alan Tull <delicious.quinoa@gmail.com> - 2017-02-15 23:50 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Moritz Fischer <moritz.fischer@ettus.com> - 2017-02-16 01:20 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Alan Tull <delicious.quinoa@gmail.com> - 2017-02-16 18:50 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Jason Gunthorpe <jgunthorpe@obsidianresearch.com> - 2017-02-16 19:00 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Moritz Fischer <moritz.fischer@ettus.com> - 2017-02-16 19:20 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Yves Vandervennet <yves.vandervennet@linux.intel.com> - 2017-02-17 23:30 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Moritz Fischer <moritz.fischer@ettus.com> - 2017-02-18 03:40 +0100
                RE: [RFC 7/8] fpga-region: add sysfs interface "Nadathur, Sundar" <sundar.nadathur@intel.com> - 2017-02-18 13:50 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Alan Tull <delicious.quinoa@gmail.com> - 2017-02-18 21:20 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Moritz Fischer <moritz.fischer@ettus.com> - 2017-02-18 22:00 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Alan Tull <delicious.quinoa@gmail.com> - 2017-02-19 16:10 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Alan Tull <delicious.quinoa@gmail.com> - 2017-02-20 00:20 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Moritz Fischer <moritz.fischer@ettus.com> - 2017-02-21 01:00 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Alan Tull <delicious.quinoa@gmail.com> - 2017-02-21 19:40 +0100
                RE: [RFC 7/8] fpga-region: add sysfs interface "Nadathur, Sundar" <sundar.nadathur@intel.com> - 2017-02-22 04:20 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Moritz Fischer <moritz.fischer@ettus.com> - 2017-02-22 04:50 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Jason Gunthorpe <jgunthorpe@obsidianresearch.com> - 2017-02-22 06:20 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Moritz Fischer <moritz.fischer@ettus.com> - 2017-02-22 06:40 +0100
                RE: [RFC 7/8] fpga-region: add sysfs interface "Nadathur, Sundar" <sundar.nadathur@intel.com> - 2017-02-22 06:50 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Moritz Fischer <moritz.fischer@ettus.com> - 2017-02-22 07:10 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Jason Gunthorpe <jgunthorpe@obsidianresearch.com> - 2017-02-22 17:50 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Moritz Fischer <moritz.fischer@ettus.com> - 2017-02-22 19:00 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Jason Gunthorpe <jgunthorpe@obsidianresearch.com> - 2017-02-22 19:00 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Moritz Fischer <moritz.fischer@ettus.com> - 2017-02-22 19:00 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Alan Tull <delicious.quinoa@gmail.com> - 2017-02-22 17:40 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Moritz Fischer <moritz.fischer@ettus.com> - 2017-02-22 17:50 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Alan Tull <delicious.quinoa@gmail.com> - 2017-02-22 18:00 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Moritz Fischer <moritz.fischer@ettus.com> - 2017-02-28 00:00 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface matthew.gerlach@linux.intel.com - 2017-02-28 07:30 +0100
                Re: [RFC 7/8] fpga-region: add sysfs interface Alan Tull <delicious.quinoa@gmail.com> - 2017-02-28 13:40 +0100
        Re: [RFC 7/8] fpga-region: add sysfs interface Anatolij Gustschin <agust@denx.de> - 2017-02-15 22:30 +0100

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