Message-ID: <CADnq5_Mg1vmpL-8N8kZY_yhsT982xjVOGj5-JuBZPGXVupzCKA@mail.gmail.com>
Date:   Tue, 25 Apr 2017 11:00:28 -0400
From:   Alex Deucher <alexdeucher@...il.com>
To:     Christian König <deathsimple@...afone.de>
Cc:     Bjorn Helgaas <helgaas@...nel.org>,
        Linux PCI <linux-pci@...r.kernel.org>,
        Maling list - DRI developers 
        <dri-devel@...ts.freedesktop.org>,
        platform-driver-x86@...r.kernel.org,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/4] x86/PCI: Enable a 64bit BAR on AMD Family 15h (Models
 30h-3fh) Processors v2

On Tue, Apr 25, 2017 at 9:19 AM, Christian König
<deathsimple@...afone.de> wrote:
> From: Christian König <christian.koenig@....com>
>
> Most BIOS don't enable this because of compatibility reasons.
>
> Manually enable a 64bit BAR of 64GB size so that we have
> enough room for PCI devices.
>
> v2: style cleanups, increase size, add resource name, set correct flags,
>     print message that windows was added
>
> Signed-off-by: Christian König <christian.koenig@....com>
> ---
>  arch/x86/pci/fixup.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
>
> diff --git a/arch/x86/pci/fixup.c b/arch/x86/pci/fixup.c
> index 6d52b94..8d949c4 100644
> --- a/arch/x86/pci/fixup.c
> +++ b/arch/x86/pci/fixup.c
> @@ -571,3 +571,56 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x2fc0, pci_invalid_bar);
>  DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x6f60, pci_invalid_bar);
>  DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x6fa0, pci_invalid_bar);
>  DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x6fc0, pci_invalid_bar);
> +
> +static void pci_amd_enable_64bit_bar(struct pci_dev *dev)
> +{
> +       uint32_t base, limit, high;
> +       struct resource *res, *conflict;
> +       unsigned i;
> +
> +       for (i = 0; i < 8; ++i) {
> +               pci_read_config_dword(dev, 0x80 + i * 0x8, &base);
> +               pci_read_config_dword(dev, 0x180 + i * 0x4, &high);

Might be nice to define names for the register offsets.


> +
> +               /* Is this slot free? */
> +               if ((base & 0x3) == 0x0)
> +                       break;
> +
> +               base >>= 8;
> +               base |= high << 24;
> +
> +               /* Abort if a slot already configures a 64bit BAR. */
> +               if (base > 0x10000)
> +                       return;
> +       }
> +       if (i == 8)
> +               return;
> +
> +       res = kzalloc(sizeof(*res), GFP_KERNEL);
> +       if (!res)
> +               return;
> +
> +       res->name = "PCI Bus 0000:00";
> +       res->flags = IORESOURCE_PREFETCH | IORESOURCE_MEM |
> +               IORESOURCE_MEM_64 | IORESOURCE_WINDOW;
> +       res->start = 0x100000000;
> +       res->end = 0xfd00000000 - 1;
> +
> +       /* Just grab the free area behind system memory for this */
> +       while ((conflict = request_resource_conflict(&iomem_resource, res)))
> +               res->start = conflict->end + 1;
> +
> +       dev_info(&dev->dev, "adding root bus resource %pR\n", res);
> +
> +       base = ((res->start >> 8) & 0xffffff00) | 0x3;
> +       limit = ((res->end + 1) >> 8) & 0xffffff00;
> +       high = ((res->start >> 40) & 0xff) |
> +               ((((res->end + 1) >> 40) & 0xff) << 16);
> +
> +       pci_write_config_dword(dev, 0x180 + i * 0x4, high);
> +       pci_write_config_dword(dev, 0x84 + i * 0x8, limit);
> +       pci_write_config_dword(dev, 0x80 + i * 0x8, base);

Same here.  Either way:
Reviewed-by: Alex Deucher <alexander.deucher@....com>

> +
> +       pci_bus_add_resource(dev->bus, res, 0);
> +}
> +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_AMD, 0x141b, pci_amd_enable_64bit_bar);
> --
> 2.7.4
>
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