1 files changed, 31 insertions, 0 deletions

diff --git a/arch/x86/kernel/amd_nb.c b/arch/x86/kernel/amd_nb.c
index 013c1810ce72..be16854591cc 100644
--- a/arch/x86/kernel/amd_nb.c
+++ b/arch/x86/kernel/amd_nb.c
@@ -119,6 +119,37 @@ bool __init early_is_amd_nb(u32 device)
         return false;
 }
 
+struct resource *amd_get_mmconfig_range(struct resource *res)
+{
+        u32 address;
+        u64 base, msr;
+        unsigned segn_busn_bits;
+
+        if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
+                return NULL;
+
+        /* assume all cpus from fam10h have mmconfig */
+        if (boot_cpu_data.x86 < 0x10)
+                return NULL;
+
+        address = MSR_FAM10H_MMIO_CONF_BASE;
+        rdmsrl(address, msr);
+
+        /* mmconfig is not enabled */
+        if (!(msr & FAM10H_MMIO_CONF_ENABLE))
+                return NULL;
+
+        base = msr & (FAM10H_MMIO_CONF_BASE_MASK<<FAM10H_MMIO_CONF_BASE_SHIFT);
+
+        segn_busn_bits = (msr >> FAM10H_MMIO_CONF_BUSRANGE_SHIFT) &
+                         FAM10H_MMIO_CONF_BUSRANGE_MASK;
+
+        res->flags = IORESOURCE_MEM;
+        res->start = base;
+        res->end = base + (1ULL<<(segn_busn_bits + 20)) - 1;
+        return res;
+}
+
 int amd_get_subcaches(int cpu)
 {
         struct pci_dev *link = node_to_amd_nb(amd_get_nb_id(cpu))->link;