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From:   Rob Herring <robh+dt@kernel.org>
Date:   Mon, 26 Oct 2020 13:41:43 -0500
Message-ID: <CAL_JsqJdwF26_2Fpz5=jGeLCGkySpdC0ZCJGaMvHFoGwJ898aQ@mail.gmail.com>
Subject: Re: [PATCH 2/4] PCI: tegra: Map configuration space as strongly ordered
To:     Vidya Sagar <vidyas@nvidia.com>
Cc:     Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jon Hunter <jonathanh@nvidia.com>, amanharitsh123@gmail.com,
        dinghao.liu@zju.edu.cn, Krzysztof Wilczynski <kw@linux.com>,
        PCI <linux-pci@vger.kernel.org>,
        linux-tegra <linux-tegra@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        kthota@nvidia.com, Manikanta Maddireddy <mmaddireddy@nvidia.com>,
        sagar.tv@gmail.com
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On Mon, Oct 26, 2020 at 1:55 AM Vidya Sagar <vidyas@nvidia.com> wrote:
>
> As specified in the comment for pci_remap_cfgspace() define in
> arch/arm64/include/asm/io.h file, PCIe configuration space should be
> mapped as strongly ordered. Hence changing to dev_pci_remap_cfgspace()

Strictly speaking, strongly ordered is ARMv6/7 terminology. For v8,
it's 'nGnRnE' which is what the comment says.

> from devm_ioremap_resource() for mapping DBI space as that is nothing
> but the root port's own configuration space.
>
> Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
> ---
>  drivers/pci/controller/dwc/pcie-tegra194.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
> index b172b1d49713..7a0c64436861 100644
> --- a/drivers/pci/controller/dwc/pcie-tegra194.c
> +++ b/drivers/pci/controller/dwc/pcie-tegra194.c
> @@ -2108,7 +2108,9 @@ static int tegra_pcie_dw_probe(struct platform_device *pdev)
>         }
>         pcie->dbi_res = dbi_res;
>
> -       pci->dbi_base = devm_ioremap_resource(dev, dbi_res);
> +       pci->dbi_base = devm_pci_remap_cfgspace(dev,
> +                                               dbi_res->start,
> +                                               resource_size(dbi_res));

This is all going to get removed anyways as I'm working on moving DBI
and other region setup into the DWC core. I guess better to do this
change first and make it explicit.

Rob