Re: [PATCH 02/16] fpga: add FPGA device framework

From	Wu Hao <hao.wu@intel.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 02/16] fpga: add FPGA device framework
Date	2017-04-01 14:30 +0200
Message-ID	<trqkh-2Bi-3@gated-at.bofh.it> (permalink)
References	<tqHdv-69w-11@gated-at.bofh.it> <tqHdw-69w-35@gated-at.bofh.it> <tqXUZ-Kk-1@gated-at.bofh.it> <tqZDr-1Hf-9@gated-at.bofh.it> <tra5Q-eL-27@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On Fri, Mar 31, 2017 at 12:01:13PM -0700, matthew.gerlach@linux.intel.com wrote:
> On Fri, 31 Mar 2017, Wu Hao wrote:
> >On Fri, Mar 31, 2017 at 08:09:09AM +0200, Greg KH wrote:
> >>On Thu, Mar 30, 2017 at 08:08:02PM +0800, Wu Hao wrote:
> >>>During FPGA device (e.g PCI-based) discovery, platform devices are
> >>>registered for different FPGA function units. But the device node path
> >>>isn't quite friendly to applications.
> >>>
> >>>Consider this case, applications want to access child device's sysfs file
> >>>for some information.
> >>>
> >>>1) Access using bus-based path (e.g PCI)
> >>>
> >>>  /sys/bus/pci/devices/xxxxx/fpga_func_a.0/sysfs_file
> >>>
> >>>  From the path, it's clear which PCI device is the parent, but not perfect
> >>>  solution for applications. PCI device BDF is not fixed, application may
> >>>  need to search all PCI device to find the actual FPGA Device.
> >>>
> >>>2) Or access using platform device path
> >>>
> >>>  /sys/bus/platform/devices/fpga_func_a.0/sysfs_file
> >>>
> >>>  Applications find the actual function by name easily, but no information
> >>>  about which fpga device it belongs to. It's quite confusing if multiple
> >>>  FPGA devices are in one system.
> >>>
> >>>'FPGA Device' class is introduced to resolve this problem. Each node under
> >>>this class represents a fpga device, which may have one or more child
> >>>devices. Applications only need to search under this FPGA Device class
> >>>folder to find the child device node it needs.
> >>>
> >>>For example, for the platform has 2 fpga devices, each fpga device has
> >>>3 child devices, the hierarchy looks like this.
> >>>
> >>>Two nodes are under /sys/class/fpga/:
> >>>/sys/class/fpga/fpga.0
> >>>/sys/class/fpga/fpga.1
> >>>
> >>>Each node has 1 function A device and 2 function B devices:
> >>>/sys/class/fpga/fpga.0/func_a.0
> >>>/sys/class/fpga/fpga.0/func_b.0
> >>>/sys/class/fpga/fpga.0/func_b.1
> >>>
> >>>/sys/class/fpga/fpga.1/func_a.1
> >>>/sys/class/fpga/fpga.1/func_b.2
> >>>/sys/class/fpga/fpga.1/func_b.3
> >>>
> >>>This following APIs are provided by FPGA device framework:
> >>>* fpga_dev_create
> >>>  Create fpga device under the given parent device.
> >>>* fpga_dev_destroy
> >>>  Destroy fpga device
> >>>
> >>>The following sysfs files are created:
> >>>* /sys/class/fpga/<fpga.x>/name
> >>>  Name of the fpga device.
> >>
> >>How does this interact with the existing "fpga class" that is in the
> >>kernel already?
> >
> >The fpga-dev introduced by this patch, is only a container device, and
> 
> I completely understand the need for a container device.  The fpga-region is
> also primarily a container, and in some cases the fpga-region may represent
> the entire fpga.  Over time this code may become redundant.

Thanks a lot for your review and comments.

I feel that the fpga-region implies that it supports reconfiguration, but
in our cases, the Intel FPGA device, doesn't have base fpga-region for
full reconfiguration, but many accelerators with partial reconfiguration
support. A fpga-region brings together everything needed for the
reconfiguration, and a fpga-dev is trying to brings everything on a FPGA
device together, including fpga-region/bridge/manager, access different
accelerators and other function units.

I think it's not mandatory to use fpga-dev, as fpga-dev is just trying to
provide one more option here for some complex hardware.

Thanks
Hao
 
> >drivers could register different functions under it. Per my understanding,
> >the existing "fpga class", including fpga-region, fpga-bridge and
> >fpga-manager, is used to provide reconfiguration function for FPGA. So
> >driver can create child node using this existing "fpga class" to provide
> >FPGA reconfiguration function, and more nodes under this container for
> >different functions for given FPGA device.
> >
> >For Intel FPGA device, partial reconfiguration is only one function of
> >Intel FPGA Management Engine (FME). FME driver creates fpga_manager under
> >below path for partial reconfiguration, and other interfaces for more
> >functions, e.g power management, virtualization support and etc.
> >
> >/sys/class/fpga/<fpga.x>/<intel-fpga-fme.x>/fpga_manager
> >
> >Thanks
> >Hao
> >
> >>
> >>thanks,
> >>
> >>greg k-h
> >--
> >To unsubscribe from this list: send the line "unsubscribe linux-fpga" in
> >the body of a message to majordomo@vger.kernel.org
> >More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >

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

csiph-web