linux-kernel - Re: [PATCH v6 5/6] PCI: uniphier: Add iATU register support

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Message-ID: <CAL_Jsq+HnaosmJgekrS-DynGvNR742m00vLN1yCiZ4YBf3T2-Q@mail.gmail.com>
Date:   Thu, 3 Sep 2020 16:12:10 -0600
From:   Rob Herring <robh+dt@...nel.org>
To:     Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
Cc:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Jingoo Han <jingoohan1@...il.com>,
        Gustavo Pimentel <gustavo.pimentel@...opsys.com>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Marc Zyngier <maz@...nel.org>, PCI <linux-pci@...r.kernel.org>,
        devicetree@...r.kernel.org,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Masami Hiramatsu <masami.hiramatsu@...aro.org>,
        Jassi Brar <jaswinder.singh@...aro.org>
Subject: Re: [PATCH v6 5/6] PCI: uniphier: Add iATU register support

On Fri, Aug 21, 2020 at 1:05 AM Kunihiko Hayashi
<hayashi.kunihiko@...ionext.com> wrote:
>
> On 2020/08/18 1:48, Rob Herring wrote:
> > On Fri, Aug 7, 2020 at 4:25 AM Kunihiko Hayashi
> > <hayashi.kunihiko@...ionext.com> wrote:
> >>
> >> This gets iATU register area from reg property. In Synopsys DWC version
> >> 4.80 or later, since iATU register area is separated from core register
> >> area, this area is necessary to get from DT independently.
> >>
> >> Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
> >> ---
> >>   drivers/pci/controller/dwc/pcie-uniphier.c | 5 +++++
> >>   1 file changed, 5 insertions(+)
> >>
> >> diff --git a/drivers/pci/controller/dwc/pcie-uniphier.c b/drivers/pci/controller/dwc/pcie-uniphier.c
> >> index 55a7166..93ef608 100644
> >> --- a/drivers/pci/controller/dwc/pcie-uniphier.c
> >> +++ b/drivers/pci/controller/dwc/pcie-uniphier.c
> >> @@ -471,6 +471,11 @@ static int uniphier_pcie_probe(struct platform_device *pdev)
> >>          if (IS_ERR(priv->pci.dbi_base))
> >>                  return PTR_ERR(priv->pci.dbi_base);
> >>
> >> +       priv->pci.atu_base =
> >> +               devm_platform_ioremap_resource_byname(pdev, "atu");
> >> +       if (IS_ERR(priv->pci.atu_base))
> >> +               priv->pci.atu_base = NULL;
> >
> > Keystone has the same 'atu' resource setup. Please move its code to
> > the DW core and use that.
>
> There are some platforms that pci.atu_base is set by other way.
> The 'atu' code shouldn't be conflicted with the following existing code.

No, it's not a conflict but needless duplication.

>    drivers/pci/controller/dwc/pci-keystone.c:              atu_base = devm_platform_ioremap_resource_byname(pdev, "atu");
>    drivers/pci/controller/dwc/pci-keystone.c:              pci->atu_base = atu_base;
>    drivers/pci/controller/dwc/pcie-designware.c:                   pci->atu_base = pci->dbi_base + DEFAULT_DBI_ATU_OFFSET;
>    drivers/pci/controller/dwc/pcie-intel-gw.c:     pci->atu_base = pci->dbi_base + data->pcie_atu_offset;

This one should have had an 'atu' region in DT.

>    drivers/pci/controller/dwc/pcie-tegra194.c:     pci->atu_base = devm_ioremap_resource(dev, atu_dma_res);

Unfortunately, a different name was used. That is the mess which is
the DW PCI controller.

>
> So I'm not sure where to move the code in the DW core.
> Is there any idea?

You just need this and then remove the keystone code:

diff --git a/drivers/pci/controller/dwc/pcie-designware.c
b/drivers/pci/controller/dwc/pcie-designware.c
index b723e0cc41fb..680084467447 100644
--- a/drivers/pci/controller/dwc/pcie-designware.c
+++ b/drivers/pci/controller/dwc/pcie-designware.c
@@ -556,6 +556,8 @@ void dw_pcie_setup(struct dw_pcie *pci)
                                       dw_pcie_iatu_unroll_enabled(pci))) {
                pci->iatu_unroll_enabled = true;
                if (!pci->atu_base)
+                       pci->atu_base =
devm_platform_ioremap_resource_byname(pdev, "atu");
+               if (IS_ERR(pci->atu_base))
                        pci->atu_base = pci->dbi_base + DEFAULT_DBI_ATU_OFFSET;
        }
        dev_dbg(pci->dev, "iATU unroll: %s\n", pci->iatu_unroll_enabled ?