1 files changed, 42 insertions, 3 deletions

diff --git a/arch/i386/pci/mmconfig.c b/arch/i386/pci/mmconfig.c
index cc787a7c030c..08a084901212 100644
--- a/arch/i386/pci/mmconfig.c
+++ b/arch/i386/pci/mmconfig.c
@@ -19,14 +19,20 @@
 /* The base address of the last MMCONFIG device accessed */
 static u32 mmcfg_last_accessed_device;
 
+static DECLARE_BITMAP(fallback_slots, 32);
+
 /*
  * Functions for accessing PCI configuration space with MMCONFIG accesses
  */
-static u32 get_base_addr(unsigned int seg, int bus)
+static u32 get_base_addr(unsigned int seg, int bus, unsigned devfn)
 {
         int cfg_num = -1;
         struct acpi_table_mcfg_config *cfg;
 
+        if (seg == 0 && bus == 0 &&
+            test_bit(PCI_SLOT(devfn), fallback_slots))
+                return 0;
+
         while (1) {
                 ++cfg_num;
                 if (cfg_num >= pci_mmcfg_config_num) {
@@ -60,7 +66,7 @@ static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
         if (!value || (bus > 255) || (devfn > 255) || (reg > 4095))
                 return -EINVAL;
 
-        base = get_base_addr(seg, bus);
+        base = get_base_addr(seg, bus, devfn);
         if (!base)
                 return pci_conf1_read(seg,bus,devfn,reg,len,value);
 
@@ -94,7 +100,7 @@ static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
         if ((bus > 255) || (devfn > 255) || (reg > 4095)) 
                 return -EINVAL;
 
-        base = get_base_addr(seg, bus);
+        base = get_base_addr(seg, bus, devfn);
         if (!base)
                 return pci_conf1_write(seg,bus,devfn,reg,len,value);
 
@@ -124,6 +130,37 @@ static struct pci_raw_ops pci_mmcfg = {
         .write =        pci_mmcfg_write,
 };
 
+/* K8 systems have some devices (typically in the builtin northbridge)
+   that are only accessible using type1
+   Normally this can be expressed in the MCFG by not listing them
+   and assigning suitable _SEGs, but this isn't implemented in some BIOS.
+   Instead try to discover all devices on bus 0 that are unreachable using MM
+   and fallback for them.
+   We only do this for bus 0/seg 0 */
+static __init void unreachable_devices(void)
+{
+        int i;
+        unsigned long flags;
+
+        for (i = 0; i < 32; i++) {
+                u32 val1;
+                u32 addr;
+
+                pci_conf1_read(0, 0, PCI_DEVFN(i, 0), 0, 4, &val1);
+                if (val1 == 0xffffffff)
+                        continue;
+
+                /* Locking probably not needed, but safer */
+                spin_lock_irqsave(&pci_config_lock, flags);
+                addr = get_base_addr(0, 0, PCI_DEVFN(i, 0));
+                if (addr != 0)
+                        pci_exp_set_dev_base(addr, 0, PCI_DEVFN(i, 0));
+                if (addr == 0 || readl((u32 *)addr) != val1)
+                        set_bit(i, fallback_slots);
+                spin_unlock_irqrestore(&pci_config_lock, flags);
+        }
+}
+
 static int __init pci_mmcfg_init(void)
 {
         if ((pci_probe & PCI_PROBE_MMCONF) == 0)
@@ -139,6 +176,8 @@ static int __init pci_mmcfg_init(void)
         raw_pci_ops = &pci_mmcfg;
         pci_probe = (pci_probe & ~PCI_PROBE_MASK) | PCI_PROBE_MMCONF;
 
+        unreachable_devices();
+
  out:
         return 0;
 }