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From:   Sergio Paracuellos <sergio.paracuellos@gmail.com>
Date:   Fri, 4 Jun 2021 23:15:56 +0200
Message-ID: <CAMhs-H98efm9bCL4ff85mcbKReBVyGsVmMw-YXRL_FXzPTyw4Q@mail.gmail.com>
Subject: Re: [PATCH 0/4] MIPS: ralink: pci: driver for Pcie controller in
 MT7621 SoCs
To:     Bjorn Helgaas <helgaas@kernel.org>
Cc:     =?UTF-8?Q?Pali_Roh=C3=A1r?= <pali@kernel.org>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        lorenzo.pieralisi@arm.com,
        "open list:MIPS" <linux-mips@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        John Crispin <john@phrozen.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Rob Herring <robh+dt@kernel.org>,
        linux-staging@lists.linux.dev,
        Greg KH <gregkh@linuxfoundation.org>,
        NeilBrown <neil@brown.name>,
        Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-pci@vger.kernel.org
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Hi Bjorn,

On Fri, Jun 4, 2021 at 9:43 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
>
> On Mon, May 31, 2021 at 03:18:45PM +0200, Pali Roh=C3=A1r wrote:
> > On Friday 21 May 2021 12:23:38 Thomas Bogendoerfer wrote:
> > > On Wed, May 19, 2021 at 11:18:36PM +0200, Sergio Paracuellos wrote:
> > > > On Wed, May 19, 2021 at 10:36 PM Bjorn Helgaas <helgaas@kernel.org>=
 wrote:
> > > > > But most of the similar drivers are in drivers/pci/controller/, w=
here
> > > > > I think it's easier to keep them up to date with changes in the P=
CI
> > > > > core.  Have you considered putting this one there?
> > > >
> > > > Most pci drivers in 'arch/mips/pci' are still using PCI_LEGACY stuf=
f.
> > > > In contrast mt7621-pci is using current pci generic apis but even m=
ost
> > > > of the code is generic enough, there is one remaining thing which
> > > > depends on mips architecture which is the iocu region configuration
> > > > which must be done in the driver itself. This is the only reason to
> > > > move this driver into 'arch/mips/pci' instead of
> > > > 'drivers/pci/controller/'. So... I am all ears to listen to
> > > > suggestions for the proper place for this driver. Thomas, do you ha=
ve
> > > > any thoughts on this?
> > >
> > > I tried to put a pci-xtalk driver into drivers/pci/controller, but
> > > Lorenzo didn't want it there for being MIPS and not DT based. So this
> > > one is DT based, but still MIPS. I'm perfectly fine putting this
> > > driver into drivers/pci/controller/
> >
> > In my personal opinion this driver could go into drivers/pci/controller=
/
>
> I'm not sure exactly what "PCI_LEGACY" above refers to.

I meant most of the drivers there are not using current generic pci
apis but still using pci legacy ones.

>
> I don't see any direct #includes of arch/mips in the driver.  I do see
> that it uses mips_cps_numiocu(), which is certainly MIPS-specific.

Yes, mips_cps_numiocu is the only stuff needed and arch specific used
by this driver.

>
> But we do have some things in drivers/pci/controller/ that only build
> on certain arches, enforced mostly by Kconfig rules, so I think you
> could do that.  We try to make so things can at least be *compiled* on
> any arch, but I know that's not always possible.
>
> So I think it would be useful to put this in drivers/pci/controller/
> somewhere because it will make it easier to see common patterns and
> refactoring opportunities.

Ok, so I will move the driver into 'drivers/pci/controller/' in v2.

Thanks,
    Sergio Paracuellos
>
> Bjorn