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From:   Saravana Kannan <saravanak@google.com>
Date:   Wed, 20 Jan 2021 11:02:09 -0800
Message-ID: <CAGETcx86HMo=gaDdXFyJ4QQ-pGXWzw2G0J=SjC-eq4K7B1zQHg@mail.gmail.com>
Subject: Re: [PATCH] PCI: dwc: layerscape: convert to builtin_platform_driver()
To:     Rob Herring <robh@kernel.org>
Cc:     Michael Walle <michael@walle.cc>,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
        PCI <linux-pci@vger.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Minghuan Lian <minghuan.Lian@nxp.com>,
        Mingkai Hu <mingkai.hu@nxp.com>, Roy Zang <roy.zang@nxp.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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On Wed, Jan 20, 2021 at 6:24 AM Rob Herring <robh@kernel.org> wrote:
>
> On Wed, Jan 20, 2021 at 4:53 AM Michael Walle <michael@walle.cc> wrote:
> >
> > fw_devlink will defer the probe until all suppliers are ready. We can't
> > use builtin_platform_driver_probe() because it doesn't retry after probe
> > deferral. Convert it to builtin_platform_driver().
>
> If builtin_platform_driver_probe() doesn't work with fw_devlink, then
> shouldn't it be fixed or removed?

I was actually thinking about this too. The problem with fixing
builtin_platform_driver_probe() to behave like
builtin_platform_driver() is that these probe functions could be
marked with __init. But there are also only 20 instances of
builtin_platform_driver_probe() in the kernel:
$ git grep ^builtin_platform_driver_probe | wc -l
20

So it might be easier to just fix them to not use
builtin_platform_driver_probe().

Michael,

Any chance you'd be willing to help me by converting all these to
builtin_platform_driver() and delete builtin_platform_driver_probe()?

-Saravana

> Then we're not fixing drivers later
> when folks start caring about deferred probe and devlink.
>
> I'd really prefer if we convert this to a module instead. (And all the
> other PCI host drivers.)
>
> > Fixes: e590474768f1 ("driver core: Set fw_devlink=on by default")
>
> This happened!?
>
> > Signed-off-by: Michael Walle <michael@walle.cc>
> > ---
> >  drivers/pci/controller/dwc/pci-layerscape.c | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pci-layerscape.c b/drivers/pci/controller/dwc/pci-layerscape.c
> > index 44ad34cdc3bc..5b9c625df7b8 100644
> > --- a/drivers/pci/controller/dwc/pci-layerscape.c
> > +++ b/drivers/pci/controller/dwc/pci-layerscape.c
> > @@ -232,7 +232,7 @@ static const struct of_device_id ls_pcie_of_match[] = {
> >         { },
> >  };
> >
> > -static int __init ls_pcie_probe(struct platform_device *pdev)
> > +static int ls_pcie_probe(struct platform_device *pdev)
> >  {
> >         struct device *dev = &pdev->dev;
> >         struct dw_pcie *pci;
> > @@ -271,10 +271,11 @@ static int __init ls_pcie_probe(struct platform_device *pdev)
> >  }
> >
> >  static struct platform_driver ls_pcie_driver = {
> > +       .probe = ls_pcie_probe,
> >         .driver = {
> >                 .name = "layerscape-pcie",
> >                 .of_match_table = ls_pcie_of_match,
> >                 .suppress_bind_attrs = true,
> >         },
> >  };
> > -builtin_platform_driver_probe(ls_pcie_driver, ls_pcie_probe);
> > +builtin_platform_driver(ls_pcie_driver);
> > --
> > 2.20.1
> >