Re: Subject: [PATCH] x86/pci: Detect mmconfig on nVidia MCP55 -v2

From: Ed Swierk
Date: Tue Feb 10 2009 - 17:57:21 EST


On Mon, Feb 9, 2009 at 6:00 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> From: Ed Swierk <eswierk@xxxxxxxxxxxxxxxxxx>
>
> Detect and enable memory-mapped PCI configuration space on the nVidia
> MCP55 southbridge. Tested against 2.6.27.4 on an Arista Networks
> development board with one MCP55, Coreboot firmware, no ACPI.
>
> v2: add multi mcp55 support, and conexist with amd quad core system by Yinghai
> also only enable it only when acpi=off or acpi is not built-in
>
> Signed-off-by: Ed Swierk <eswierk@xxxxxxxxxxxxxxxxxx>

A couple of comments below. Let me test this version before signing off.

> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
>
> ---
> arch/x86/pci/mmconfig-shared.c | 64 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 64 insertions(+)
>
> Index: linux-2.6/arch/x86/pci/mmconfig-shared.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/pci/mmconfig-shared.c
> +++ linux-2.6/arch/x86/pci/mmconfig-shared.c
> @@ -166,6 +166,68 @@ static const char __init *pci_mmcfg_amd_
> return "AMD Family 10h NB";
> }
>
> +static bool __initdata mcp55_checked;
> +static const char __init *pci_mmcfg_nvidia_mcp55(void)
> +{
> + int bus;
> + int mcp55_mmconf_found = 0;
> +
> + static const u32 extcfg_regnum = 0x90;
> + static const u32 extcfg_regsize = 4;
> + static const u32 extcfg_enable_mask = 1<<31;
> + static const u32 extcfg_start_mask = 0xff<<16;
> + static const int extcfg_start_shift = 16;
> + static const u32 extcfg_size_mask = 0x3<<28;
> + static const int extcfg_size_shift = 28;
> + static const int extcfg_sizebus[] = {0x100, 0x80, 0x40, 0x20};
> + static const u32 extcfg_base_mask[] = {0x7ff8, 0x7ffc, 0x7ffe, 0x7fff};
> + static const int extcfg_base_lshift = 25;
> +
> + /*
> + * do check if amd fam10h already took over
> + */
> + if (!acpi_disabled || pci_mmcfg_config_num || mcp55_checked)
> + return NULL;

Why skip this if !acpi_disabled? I thought we want to have the host
bridge mmconfig settings override the ACPI MCFG. At least that appears
to be the logic for other host bridges.

> + mcp55_checked = true;
> + for (bus = 0; bus < 256; bus++) {
> + u64 base;
> + u32 l, extcfg;
> + u16 vendor, device;
> + int start, size_index, end;
> +
> + raw_pci_ops->read(0, bus, PCI_DEVFN(0, 0), 0, 4, &l);

Don't we need to check devices 8, 16 and 24 as well as 0?

> + vendor = l & 0xffff;
> + device = (l >> 16) & 0xffff;
> +
> + if (PCI_VENDOR_ID_NVIDIA != vendor || 0x0369 != device)
> + continue;
> +
> + raw_pci_ops->read(0, bus, PCI_DEVFN(0, 0), extcfg_regnum,
> + extcfg_regsize, &extcfg);
> +
> + if (!(extcfg & extcfg_enable_mask))
> + continue;
> +
> + if (extend_mmcfg(1) == -1)
> + continue;
> +
> + size_index = (extcfg & extcfg_size_mask) >> extcfg_size_shift;
> + base = extcfg & extcfg_base_mask[size_index];
> + /* base could > 4G */
> + base <<= extcfg_base_lshift;
> + start = (extcfg & extcfg_start_mask) >> extcfg_start_shift;
> + end = start + extcfg_sizebus[size_index] - 1;
> + fill_one_mmcfg(base, 0, start, end);
> + mcp55_mmconf_found++;
> + }
> +
> + if (!mcp55_mmconf_found)
> + return NULL;
> +
> + return "nVidia MCP55";
> +}
> +
> struct pci_mmcfg_hostbridge_probe {
> u32 bus;
> u32 devfn;
> @@ -183,6 +245,8 @@ static struct pci_mmcfg_hostbridge_probe
> 0x1200, pci_mmcfg_amd_fam10h },
> { 0xff, PCI_DEVFN(0, 0), PCI_VENDOR_ID_AMD,
> 0x1200, pci_mmcfg_amd_fam10h },
> + { 0, PCI_DEVFN(0, 0), PCI_VENDOR_ID_NVIDIA,
> + 0x0369, pci_mmcfg_nvidia_mcp55 },
> };
>
> static int __init cmp_mmcfg(const void *x1, const void *x2)
>
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