Re: [PATCH 04/16] fpga: intel: pcie: parse feature list and create platform device for features.

From	Wu Hao <hao.wu@intel.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 04/16] fpga: intel: pcie: parse feature list and create platform device for features.
Date	2017-04-05 16:20 +0200
Message-ID	<tsTWW-3H6-17@gated-at.bofh.it> (permalink)
References	<tqHdv-69w-11@gated-at.bofh.it> <tqHdw-69w-17@gated-at.bofh.it> <tsEXT-2s7-19@gated-at.bofh.it>
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On Tue, Apr 04, 2017 at 05:09:23PM -0500, Alan Tull wrote:
> On Thu, Mar 30, 2017 at 7:08 AM, Wu Hao <hao.wu@intel.com> wrote:
> > From: Xiao Guangrong <guangrong.xiao@linux.intel.com>
> >
> > Device Featuer List structure creates a link list of feature headers
> > within the MMIO space to provide an extensiable way of adding features.
> >
> > The Intel FPGA PCIe driver walks through the feature headers to enumerate
> > feature devices, FPGA Management Engine (FME) and FPGA Port for Accelerated
> > Function Unit (AFU), and their private sub features. For feature devices,
> > it creates the platform devices and linked the private sub features into
> > their platform data.
> >
> 
> I'm still looking at this code and it's pretty new to me, but I think
> it would be desirable and not really hard to separate the code
> that enumerates from all the fixed feature code.  So pcie.c could see
> that there is a pci device out there that it knows has these memory
> mapped enumeration structs.  So it goes and reads the structs, parses
> them, and knows what drivers to probe.  The FME and AFU and other
> fpga device drivers could register their guids with the framework
> and be discoverable in that way.
> 
> That way if you need to implement a different FME or anything else, it
> could be added with a new guid to this framework and would get
> enumerated.  I'm thinking of the future and of more general usability
> of this code.
>
> Then the enumeration code wouldn't have to be 'intel' code or even
> code dedicated to FME's and AFU's.  Any FPGA with a PCIe
> port that has the right id's could have this struct and use this
> enumeration method.  Actually if the parse* enumeration code could be in a
> separate file as helper functions for the pcie code, this stuff would
> be structured for future support this of the same framework on
> embedded FPGA devices.
> 

Hi Alan

Thank you very much for the review and comments.

Actually I am not sure if the 'Device Feature List' is designed for common
usage or not, but per current implementation of Port/AFU and FME, they did
not use the exact same way for enumeration. e.g PCIe driver reads register
under Port to know the AFU MMIO region size. So for each module, it has
its own method to enumerate and prepare the resource for its platform
device. Other developers may not be able to use them for a new module.

From the whole device's point of view, do enumeration for all modules is
still a device specific thing. e.g 'Device Feature List' of the FME is in
PCI BAR0, but the location of Port/AFU's 'Device Feature List' is not
linked to FME's Device Feature List, but given (PCI BAR +  offset) by a 
FME register. So the process of enumeration may be totally different
in another device with different module.

I don't expect FME can be used without PCIE or Port/AFU now, as it ties
to them so closely. e.g give PCI Bar info for port, registers to support
PCI SRIOV function. And so does PCIe and AFU driver, e.g PCIe driver is
not only handling the enumeration, but also manage ports and access FME
registers for SRIOV function support (sriov related code is not included
in this patch set).

If we have any PCIE FPGA has FME, then we can reuse this Intel FPGA
driver directly, but if no FME, then most code can't be reused.

I fully understand your point for code reuse and agree with you that
parse* enumeration code could be in a common place as helper function.
But for others, I still have concern due to current hardware
implementation. Anyway I will continue consideration on this.

Thanks
Hao

> Alan

Thread

[PATCH 00/16] Intel FPGA Device Drivers Wu Hao <hao.wu@intel.com> - 2017-03-30 14:20 +0200
  [PATCH 02/16] fpga: add FPGA device framework Wu Hao <hao.wu@intel.com> - 2017-03-30 14:20 +0200
    Re: [PATCH 02/16] fpga: add FPGA device framework Greg KH <greg@kroah.com> - 2017-03-31 08:10 +0200
      Re: [PATCH 02/16] fpga: add FPGA device framework Wu Hao <hao.wu@intel.com> - 2017-03-31 10:00 +0200
        Re: [PATCH 02/16] fpga: add FPGA device framework Greg KH <greg@kroah.com> - 2017-03-31 11:10 +0200
          Re: [PATCH 02/16] fpga: add FPGA device framework Wu Hao <hao.wu@intel.com> - 2017-03-31 14:30 +0200
        Re: [PATCH 02/16] fpga: add FPGA device framework matthew.gerlach@linux.intel.com - 2017-03-31 21:10 +0200
          Re: [PATCH 02/16] fpga: add FPGA device framework Wu Hao <hao.wu@intel.com> - 2017-04-01 14:30 +0200
    Re: [PATCH 02/16] fpga: add FPGA device framework Greg KH <greg@kroah.com> - 2017-03-31 08:20 +0200
      Re: [PATCH 02/16] fpga: add FPGA device framework Wu Hao <hao.wu@intel.com> - 2017-03-31 15:40 +0200
        Re: [PATCH 02/16] fpga: add FPGA device framework Greg KH <greg@kroah.com> - 2017-03-31 16:20 +0200
          Re: [PATCH 02/16] fpga: add FPGA device framework Wu Hao <hao.wu@intel.com> - 2017-04-01 13:50 +0200
  [PATCH 03/16] fpga: intel: add FPGA PCIe device driver Wu Hao <hao.wu@intel.com> - 2017-03-30 14:20 +0200
    Re: [PATCH 03/16] fpga: intel: add FPGA PCIe device driver Moritz Fischer <mdf@kernel.org> - 2017-04-04 04:20 +0200
      RE: [PATCH 03/16] fpga: intel: add FPGA PCIe device driver "Wu, Hao" <hao.wu@intel.com> - 2017-04-05 15:20 +0200
  [PATCH 15/16] fpga: intel: afu: add user afu sub feature support Wu Hao <hao.wu@intel.com> - 2017-03-30 14:20 +0200
  [PATCH 12/16] fpga: intel: add FPGA Accelerated Function Unit driver basic framework Wu Hao <hao.wu@intel.com> - 2017-03-30 14:20 +0200
  [PATCH 09/16] fpga: intel: fme: add header sub feature support Wu Hao <hao.wu@intel.com> - 2017-03-30 14:20 +0200
  [PATCH 16/16] fpga: intel: afu: add FPGA_PORT_DMA_MAP/UNMAP ioctls support Wu Hao <hao.wu@intel.com> - 2017-03-30 14:20 +0200
  [PATCH 07/16] fpga: intel: add feature device infrastructure Wu Hao <hao.wu@intel.com> - 2017-03-30 14:20 +0200
  [PATCH 05/16] fpga: intel: pcie: add chardev support for feature devices Wu Hao <hao.wu@intel.com> - 2017-03-30 14:20 +0200
  [PATCH 04/16] fpga: intel: pcie: parse feature list and create platform device for features. Wu Hao <hao.wu@intel.com> - 2017-03-30 14:20 +0200
    Re: [PATCH 04/16] fpga: intel: pcie: parse feature list and create  platform device for features. Alan Tull <atull@kernel.org> - 2017-04-03 23:50 +0200
      Re: [PATCH 04/16] fpga: intel: pcie: parse feature list and create  platform device for features. Wu Hao <hao.wu@intel.com> - 2017-04-05 14:10 +0200
    Re: [PATCH 04/16] fpga: intel: pcie: parse feature list and create  platform device for features. Alan Tull <atull@kernel.org> - 2017-04-05 00:20 +0200
      Re: [PATCH 04/16] fpga: intel: pcie: parse feature list and create  platform device for features. Wu Hao <hao.wu@intel.com> - 2017-04-05 16:20 +0200
  [PATCH 10/16] fpga: intel: fme: add FPGA_GET_API_VERSION/CHECK_EXTENSION ioctls support Wu Hao <hao.wu@intel.com> - 2017-03-30 14:20 +0200
  [PATCH 14/16] fpga: intel: afu add FPGA_GET_API_VERSION/CHECK_EXTENSION ioctls support Wu Hao <hao.wu@intel.com> - 2017-03-30 14:20 +0200
  [PATCH 01/16] docs: fpga: add a document for Intel FPGA driver overview Wu Hao <hao.wu@intel.com> - 2017-03-30 14:20 +0200
    Re: [PATCH 01/16] docs: fpga: add a document for Intel FPGA driver  overview matthew.gerlach@linux.intel.com - 2017-03-31 20:30 +0200
      Re: [PATCH 01/16] docs: fpga: add a document for Intel FPGA driver overview Alan Tull <atull@kernel.org> - 2017-03-31 20:40 +0200
        Re: [PATCH 01/16] docs: fpga: add a document for Intel FPGA driver  overview Wu Hao <hao.wu@intel.com> - 2017-04-01 13:30 +0200
          Re: [PATCH 01/16] docs: fpga: add a document for Intel FPGA driver  overview Moritz Fischer <mdf@kernel.org> - 2017-04-02 16:50 +0200
            Re: [PATCH 01/16] docs: fpga: add a document for Intel FPGA driver overview Alan Tull <atull@kernel.org> - 2017-04-03 22:50 +0200
              Re: [PATCH 01/16] docs: fpga: add a document for Intel FPGA driver  overview Wu Hao <hao.wu@intel.com> - 2017-04-04 07:30 +0200
            Re: [PATCH 01/16] docs: fpga: add a document for Intel FPGA driver  overview Wu Hao <hao.wu@intel.com> - 2017-04-04 07:20 +0200
  [PATCH 06/16] fpga: intel: pcie: adds fpga_for_each_port callback for fme device Wu Hao <hao.wu@intel.com> - 2017-03-30 14:20 +0200
  [PATCH 13/16] fpga: intel: afu: add header sub feature support Wu Hao <hao.wu@intel.com> - 2017-03-30 14:20 +0200
  [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub feature support Wu Hao <hao.wu@intel.com> - 2017-03-30 14:20 +0200
    Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support Alan Tull <atull@kernel.org> - 2017-03-30 22:40 +0200
      Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support Xiao Guangrong <xiaoguangrong.eric@gmail.com> - 2017-03-31 06:20 +0200
        Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support Wu Hao <hao.wu@intel.com> - 2017-03-31 11:00 +0200
          Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support Alan Tull <atull@kernel.org> - 2017-04-03 22:30 +0200
            Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support Wu Hao <hao.wu@intel.com> - 2017-04-04 07:40 +0200
    Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support Alan Tull <atull@kernel.org> - 2017-03-31 21:20 +0200
      Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support Wu Hao <hao.wu@intel.com> - 2017-04-01 13:20 +0200
        Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support Alan Tull <atull@kernel.org> - 2017-04-03 18:40 +0200
          Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support Wu Hao <hao.wu@intel.com> - 2017-04-04 08:20 +0200
            Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support Alan Tull <atull@kernel.org> - 2017-04-05 00:40 +0200
              RE: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support "Wu, Hao" <hao.wu@intel.com> - 2017-04-05 13:50 +0200
                Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support Alan Tull <atull@kernel.org> - 2017-04-05 17:30 +0200
                Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support Alan Tull <atull@kernel.org> - 2017-04-05 17:50 +0200
                Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support Wu Hao <hao.wu@intel.com> - 2017-04-06 13:10 +0200
                Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support Alan Tull <atull@kernel.org> - 2017-04-06 21:30 +0200
                Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support Wu Hao <hao.wu@intel.com> - 2017-04-07 08:10 +0200
    Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support Alan Tull <atull@kernel.org> - 2017-04-03 23:30 +0200
      Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support matthew.gerlach@linux.intel.com - 2017-04-04 00:50 +0200
        Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support Wu Hao <hao.wu@intel.com> - 2017-04-04 09:00 +0200
      Re: [PATCH 11/16] fpga: intel: fme: add partial reconfiguration sub  feature support Wu Hao <hao.wu@intel.com> - 2017-04-04 08:40 +0200
  Re: [PATCH 00/16] Intel FPGA Device Drivers Moritz Fischer <mdf@kernel.org> - 2017-03-30 19:20 +0200
  Re: [PATCH 00/16] Intel FPGA Device Drivers Jerome Glisse <jglisse@redhat.com> - 2017-04-06 22:30 +0200

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