Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic ECAM API

From	Jayachandran C <jchandra@broadcom.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic ECAM API
Date	2016-04-16 16:40 +0200
Message-ID	<rozya-4VT-31@gated-at.bofh.it> (permalink)
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On Sat, Apr 16, 2016 at 1:01 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> On Saturday 16 April 2016 12:50:13 Jayachandran C wrote:
>> >
>> > I still think it would be better to keep the loadable PCI host drivers
>> > separate from the ACPI PCI infrastructure. There are a number of
>> > simplifications that we want to do to the DT based drivers in the long
>> > run, so it's better if that code is not shared at this level. Abstracting
>> > out the ECAM code is fine, but at that point you should be able to just
>> > call it from the ACPI layer.
>>
>> The issue is not with this patch (in my opinion). This patch is just
>> re-arranging how thunder specific data is maintained. Earlier it was
>> a container_of gen_pci, now it is ->priv of pci_config_window.
>>
>> I can see the issue in patches 12 and 13 of this patchset which adds
>> ACPI fixups into the thunder OF driver.
>
> Right, I commented on this one, because it seems to rearrange the code
> in order to do the later one.

Patches 11- 13 are not from me, and I am not completely on board
on the approach of adding the sections.We can look at reworking this.

>> The simple approach when doing modular PCI drivers would be to make
>> pci-thunder-*.c like pci-host-common.c, to be compiled in if configured.
>> The fie will contain all the Thunder quirks and can export
>> pci_thunder_ecam_ops.
>
> I would argue that we should not export anything from drivers/pci/host,
> those should really be standalone drivers that do not interact with other
> subsystems.

pci-host-common.c goes against being standalone. The files calling
pci_host_common_probe() are expected to have custom ECAM ops
the way it is written now. We need to have a reasonable way to share
those ECAM ops if needed by ACPI.

> How much code would you need to duplicate from thunder-ecam to have
> the same functionality available in ACPI? My expectation is that it's
> not really that much more compared to the code you need for sharing
> a single implementation, but you get a lower complexity here, which
> makes it easier to understand and to rework.

Like I wrote above, the sharing is really simple because both generic
ACPI and pci-host-common.c have been written for "ECAM with quirks".

The whole pci-thunder-*.c is to support thunder PCI quirks since the
generic OF is handled by pci-host-common.c and generic ECAM is now
separated -  duplicating the whole file for ACPI will be bad.

Any suggestions on how to do this better would be really welcome.

Thanks,
JC.

Thread

[PATCH V6 00/13] Support for generic ACPI based PCI host controller Tomasz Nowicki <tn@semihalf.com> - 2016-04-15 19:10 +0200
  [PATCH V6 11/13] pci, acpi: Match PCI config space accessors against platfrom specific quirks. Tomasz Nowicki <tn@semihalf.com> - 2016-04-15 19:10 +0200
    Re: [PATCH V6 11/13] pci, acpi: Match PCI config space accessors  against platfrom specific quirks. "liudongdong (C)" <liudongdong3@huawei.com> - 2016-04-18 14:00 +0200
      Re: [PATCH V6 11/13] pci, acpi: Match PCI config space accessors  against platfrom specific quirks. Tomasz Nowicki <tn@semihalf.com> - 2016-04-18 14:30 +0200
  [PATCH V6 13/13] pci, pci-thunder-pem: Add ACPI support for ThunderX PEM. Tomasz Nowicki <tn@semihalf.com> - 2016-04-15 19:10 +0200
  [PATCH V6 02/13] pci, acpi: Provide generic way to assign bus domain number. Tomasz Nowicki <tn@semihalf.com> - 2016-04-15 19:10 +0200
    Re: [PATCH V6 02/13] pci, acpi: Provide generic way to assign bus  domain number. Bjorn Helgaas <helgaas@kernel.org> - 2016-04-27 04:30 +0200
      Re: [PATCH V6 02/13] pci, acpi: Provide generic way to assign bus  domain number. Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> - 2016-04-27 13:20 +0200
        Re: [PATCH V6 02/13] pci, acpi: Provide generic way to assign bus  domain number. Bjorn Helgaas <helgaas@kernel.org> - 2016-04-27 18:50 +0200
          Re: [PATCH V6 02/13] pci, acpi: Provide generic way to assign bus  domain number. Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> - 2016-04-27 19:40 +0200
            Re: [PATCH V6 02/13] pci, acpi: Provide generic way to assign bus  domain number. Liviu.Dudau@arm.com - 2016-04-28 10:20 +0200
      Re: [PATCH V6 02/13] pci, acpi: Provide generic way to assign bus  domain number. Tomasz Nowicki <tn@semihalf.com> - 2016-04-27 14:10 +0200
  [PATCH V6 12/13] pci, pci-thunder-ecam: Add ACPI support for ThunderX ECAM. Tomasz Nowicki <tn@semihalf.com> - 2016-04-15 19:10 +0200
    Re: [PATCH V6 12/13] pci, pci-thunder-ecam: Add ACPI support for  ThunderX ECAM. Tomasz Nowicki <tn@semihalf.com> - 2016-04-19 12:30 +0200
      Re: [Linaro-acpi] [PATCH V6 12/13] pci, pci-thunder-ecam: Add ACPI  support for ThunderX ECAM. G Gregory <graeme.gregory@linaro.org> - 2016-04-19 12:50 +0200
        Re: [Linaro-acpi] [PATCH V6 12/13] pci, pci-thunder-ecam: Add ACPI  support for ThunderX ECAM. Graeme Gregory <gg@slimlogic.co.uk> - 2016-04-19 13:20 +0200
          Re: [Linaro-acpi] [PATCH V6 12/13] pci, pci-thunder-ecam: Add ACPI  support for ThunderX ECAM. Tomasz Nowicki <tn@semihalf.com> - 2016-04-19 13:30 +0200
            Re: [Linaro-acpi] [PATCH V6 12/13] pci, pci-thunder-ecam: Add ACPI  support for ThunderX ECAM. G Gregory <graeme.gregory@linaro.org> - 2016-04-19 14:30 +0200
  [PATCH V6 08/13] PCI: generic, thunder: update to use generic ECAM API Tomasz Nowicki <tn@semihalf.com> - 2016-04-15 19:10 +0200
    Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic ECAM API Arnd Bergmann <arnd@arndb.de> - 2016-04-15 20:50 +0200
      Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic  ECAM API Jayachandran C <jchandra@broadcom.com> - 2016-04-16 09:30 +0200
        Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic ECAM API Arnd Bergmann <arnd@arndb.de> - 2016-04-16 09:40 +0200
          Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic  ECAM API Jayachandran C <jchandra@broadcom.com> - 2016-04-16 16:40 +0200
            Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic  ECAM API Tomasz Nowicki <tn@semihalf.com> - 2016-04-18 15:10 +0200
              Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic ECAM API Arnd Bergmann <arnd@arndb.de> - 2016-04-18 16:50 +0200
                Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic  ECAM API Tomasz Nowicki <tn@semihalf.com> - 2016-04-18 21:40 +0200
                Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic ECAM API Arnd Bergmann <arnd@arndb.de> - 2016-04-19 15:10 +0200
                Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic  ECAM API Tomasz Nowicki <tn@semihalf.com> - 2016-04-21 11:30 +0200
                Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic ECAM API Arnd Bergmann <arnd@arndb.de> - 2016-04-21 11:40 +0200
                Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic  ECAM API Tomasz Nowicki <tn@semihalf.com> - 2016-04-21 12:10 +0200
                Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic  ECAM API Jon Masters <jcm@redhat.com> - 2016-04-22 16:40 +0200
                Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic  ECAM API David Daney <ddaney.cavm@gmail.com> - 2016-04-22 18:10 +0200
    Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic ECAM API Arnd Bergmann <arnd@arndb.de> - 2016-04-19 23:50 +0200
      Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic  ECAM API Jayachandran C <jchandra@broadcom.com> - 2016-04-20 02:30 +0200
  [PATCH V6 04/13] pci, of: Move the PCI I/O space management to PCI core code. Tomasz Nowicki <tn@semihalf.com> - 2016-04-15 19:10 +0200
  [PATCH V6 09/13] pci, acpi: Support for ACPI based generic PCI host controller Tomasz Nowicki <tn@semihalf.com> - 2016-04-15 19:10 +0200
    Re: [PATCH V6 09/13] pci, acpi: Support for ACPI based generic PCI  host controller Jayachandran C <jchandra@broadcom.com> - 2016-04-20 21:20 +0200
      Re: [PATCH V6 09/13] pci, acpi: Support for ACPI based generic PCI  host controller Tomasz Nowicki <tn@semihalf.com> - 2016-04-21 11:10 +0200
        Re: [PATCH V6 09/13] pci, acpi: Support for ACPI based generic PCI  host controller Jayachandran C <jchandra@broadcom.com> - 2016-04-22 15:00 +0200
        Re: [PATCH V6 09/13] pci, acpi: Support for ACPI based generic PCI  host controller Jon Masters <jcm@redhat.com> - 2016-04-22 16:50 +0200
          Re: [PATCH V6 09/13] pci, acpi: Support for ACPI based generic PCI  host controller Jon Masters <jcm@redhat.com> - 2016-04-23 17:30 +0200
  [PATCH V6 10/13] arm64, pci, acpi: Start using ACPI based PCI host controller driver for ARM64. Tomasz Nowicki <tn@semihalf.com> - 2016-04-15 19:10 +0200
  [PATCH V6 06/13] arm64, pci, acpi: ACPI support for legacy IRQs parsing and consolidation with DT code. Tomasz Nowicki <tn@semihalf.com> - 2016-04-15 19:20 +0200
    Re: [PATCH V6 06/13] arm64, pci, acpi: ACPI support for legacy IRQs  parsing and consolidation with DT code. Bjorn Helgaas <helgaas@kernel.org> - 2016-04-27 04:50 +0200
      Re: [PATCH V6 06/13] arm64, pci, acpi: ACPI support for legacy IRQs  parsing and consolidation with DT code. Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> - 2016-04-27 13:50 +0200
  [PATCH V6 07/13] PCI: Provide common functions for ECAM mapping Tomasz Nowicki <tn@semihalf.com> - 2016-04-15 19:20 +0200
    Re: [PATCH V6 07/13] PCI: Provide common functions for ECAM mapping Arnd Bergmann <arnd@arndb.de> - 2016-04-15 20:50 +0200
  [PATCH V6 01/13] pci, acpi, x86, ia64: Move ACPI host bridge device companion assignment to core code. Tomasz Nowicki <tn@semihalf.com> - 2016-04-15 19:20 +0200
    Re: [PATCH V6 01/13] pci, acpi, x86, ia64: Move ACPI host bridge  device companion assignment to core code. Bjorn Helgaas <helgaas@kernel.org> - 2016-04-27 00:40 +0200
      Re: [PATCH V6 01/13] pci, acpi, x86, ia64: Move ACPI host bridge  device companion assignment to core code. Tomasz Nowicki <tn@semihalf.com> - 2016-04-27 12:20 +0200
    Re: [PATCH V6 01/13] pci, acpi, x86, ia64: Move ACPI host bridge  device companion assignment to core code. Bjorn Helgaas <helgaas@kernel.org> - 2016-04-27 04:50 +0200
  [PATCH V6 03/13] x86, ia64: Include acpi_pci_{add|remove}_bus to the default pcibios_{add|remove}_bus implementation. Tomasz Nowicki <tn@semihalf.com> - 2016-04-15 19:20 +0200
    Re: [PATCH V6 03/13] x86, ia64: Include acpi_pci_{add|remove}_bus to  the default pcibios_{add|remove}_bus implementation. Bjorn Helgaas <helgaas@kernel.org> - 2016-04-27 04:40 +0200
      Re: [PATCH V6 03/13] x86, ia64: Include acpi_pci_{add|remove}_bus to  the default pcibios_{add|remove}_bus implementation. Tomasz Nowicki <tn@semihalf.com> - 2016-04-27 15:30 +0200
  [PATCH V6 05/13] acpi, pci: Support IO resources when parsing PCI host bridge resources. Tomasz Nowicki <tn@semihalf.com> - 2016-04-15 19:20 +0200
    Re: [PATCH V6 05/13] acpi, pci: Support IO resources when parsing  PCI host bridge resources. Bjorn Helgaas <helgaas@kernel.org> - 2016-04-27 04:40 +0200
      Re: [PATCH V6 05/13] acpi, pci: Support IO resources when parsing PCI  host bridge resources. Jon Masters <jcm@redhat.com> - 2016-04-27 07:40 +0200
      Re: [PATCH V6 05/13] acpi, pci: Support IO resources when parsing  PCI host bridge resources. Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> - 2016-04-27 16:30 +0200
        Re: [PATCH V6 05/13] acpi, pci: Support IO resources when parsing  PCI host bridge resources. Liviu.Dudau@arm.com - 2016-04-27 17:20 +0200
          Re: [PATCH V6 05/13] acpi, pci: Support IO resources when parsing  PCI host bridge resources. Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> - 2016-04-27 18:10 +0200
  Re: [PATCH V6 00/13] Support for generic ACPI based PCI host  controller Jon Masters <jcm@redhat.com> - 2016-04-15 20:20 +0200
    Re: [PATCH V6 00/13] Support for generic ACPI based PCI host controller Jayachandran C <jchandra@broadcom.com> - 2016-04-16 17:40 +0200
      Re: [PATCH V6 00/13] Support for generic ACPI based PCI host  controller Tomasz Nowicki <tn@semihalf.com> - 2016-04-18 15:40 +0200
        Re: [PATCH V6 00/13] Support for generic ACPI based PCI host controller Arnd Bergmann <arnd@arndb.de> - 2016-04-18 16:40 +0200
          Re: [PATCH V6 00/13] Support for generic ACPI based PCI host  controller Tomasz Nowicki <tn@semihalf.com> - 2016-04-18 17:30 +0200
    Re: [PATCH V6 00/13] Support for generic ACPI based PCI host controller Martinez Kristofer <kristofer.s.martinez@gmail.com> - 2016-04-17 11:30 +0200
  Re: [PATCH V6 00/13] Support for generic ACPI based PCI host controller Duc Dang <dhdang@apm.com> - 2016-04-16 20:40 +0200
  Re: [PATCH V6 00/13] Support for generic ACPI based PCI host  controller Sinan Kaya <okaya@codeaurora.org> - 2016-04-17 06:20 +0200
  Re: [PATCH V6 00/13] Support for generic ACPI based PCI host  controller Jeremy Linton <jeremy.linton@arm.com> - 2016-04-25 19:30 +0200

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