From: Christian König <christian.koe...@amd.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.koe...@amd.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);
+
+               /* 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);
+
+       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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