1 files changed, 53 insertions, 10 deletions

diff --git a/arch/x86_64/pci/mmconfig.c b/arch/x86_64/pci/mmconfig.c
index a0838c4a94e4..9c4f907e301c 100644
--- a/arch/x86_64/pci/mmconfig.c
+++ b/arch/x86_64/pci/mmconfig.c
@@ -8,10 +8,13 @@
 #include <linux/pci.h>
 #include <linux/init.h>
 #include <linux/acpi.h>
+#include <linux/bitmap.h>
 #include "pci.h"
 
 #define MMCONFIG_APER_SIZE (256*1024*1024)
 
+static DECLARE_BITMAP(fallback_slots, 32);
+
 /* Static virtual mapping of the MMCONFIG aperture */
 struct mmcfg_virt {
         struct acpi_table_mcfg_config *cfg;
@@ -19,7 +22,7 @@ struct mmcfg_virt {
 };
 static struct mmcfg_virt *pci_mmcfg_virt;
 
-static char *get_virt(unsigned int seg, int bus)
+static char *get_virt(unsigned int seg, unsigned bus)
 {
         int cfg_num = -1;
         struct acpi_table_mcfg_config *cfg;
@@ -27,10 +30,9 @@ static char *get_virt(unsigned int seg, int bus)
         while (1) {
                 ++cfg_num;
                 if (cfg_num >= pci_mmcfg_config_num) {
-                        /* something bad is going on, no cfg table is found. */
-                        /* so we fall back to the old way we used to do this */
-                        /* and just rely on the first entry to be correct. */
-                        return pci_mmcfg_virt[0].virt;
+                        /* Not found - fall back to type 1. This happens
+                           e.g. on the internal devices of a K8 northbridge. */
+                        return NULL;
                 }
                 cfg = pci_mmcfg_virt[cfg_num].cfg;
                 if (cfg->pci_segment_group_number != seg)
@@ -41,20 +43,30 @@ static char *get_virt(unsigned int seg, int bus)
         }
 }
 
-static inline char *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn)
+static char *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn)
 {
-
-        return get_virt(seg, bus) + ((bus << 20) | (devfn << 12));
+        char *addr;
+        if (seg == 0 && bus == 0 && test_bit(PCI_SLOT(devfn), &fallback_slots))
+                return NULL;
+        addr = get_virt(seg, bus);
+        if (!addr)
+                return NULL;
+        return addr + ((bus << 20) | (devfn << 12));
 }
 
 static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
                           unsigned int devfn, int reg, int len, u32 *value)
 {
-        char *addr = pci_dev_base(seg, bus, devfn);
+        char *addr;
 
+        /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
         if (unlikely(!value || (bus > 255) || (devfn > 255) || (reg > 4095)))
                 return -EINVAL;
 
+        addr = pci_dev_base(seg, bus, devfn);
+        if (!addr)
+                return pci_conf1_read(seg,bus,devfn,reg,len,value);
+
         switch (len) {
         case 1:
                 *value = readb(addr + reg);
@@ -73,11 +85,16 @@ static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
 static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
                            unsigned int devfn, int reg, int len, u32 value)
 {
-        char *addr = pci_dev_base(seg, bus, devfn);
+        char *addr;
 
+        /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
         if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
                 return -EINVAL;
 
+        addr = pci_dev_base(seg, bus, devfn);
+        if (!addr)
+                return pci_conf1_write(seg,bus,devfn,reg,len,value);
+
         switch (len) {
         case 1:
                 writeb(value, addr + reg);
@@ -98,6 +115,30 @@ 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;
+        for (i = 0; i < 32; i++) {
+                u32 val1;
+                char *addr;
+
+                pci_conf1_read(0, 0, PCI_DEVFN(i,0), 0, 4, &val1);
+                if (val1 == 0xffffffff)
+                        continue;
+                addr = pci_dev_base(0, 0, PCI_DEVFN(i, 0));
+                if (addr == NULL|| readl(addr) != val1) {
+                        set_bit(i, &fallback_slots);
+                }
+        }
+}
+
 static int __init pci_mmcfg_init(void)
 {
         int i;
@@ -128,6 +169,8 @@ static int __init pci_mmcfg_init(void)
                 printk(KERN_INFO "PCI: Using MMCONFIG at %x\n", pci_mmcfg_config[i].base_address);
         }
 
+        unreachable_devices();
+
         raw_pci_ops = &pci_mmcfg;
         pci_probe = (pci_probe & ~PCI_PROBE_MASK) | PCI_PROBE_MMCONF;