[POWERPC] Disable PCI IO/Mem on a device when resources can't be allocated

This patch changes the PowerPC PCI code to disable IO and/or Memory
decoding on a PCI device when a resource of that type failed to be
allocated.  This is done to avoid having unallocated dangling BARs
enabled that might try to decode on top of other devices.

If a proper resource is assigned later on, then pci_enable_device()
will take care of re-enabling decoding.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 10 insertions, 3 deletions

diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 1037b3a093ee..88838b0f8b90 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -1034,7 +1034,7 @@ clear_resource:
         }
 }
 
-static inline void __devinit alloc_resource(struct pci_dev *dev, int idx)
+static inline int __devinit alloc_resource(struct pci_dev *dev, int idx)
 {
         struct resource *pr, *r = &dev->resource[idx];
 
@@ -1058,7 +1058,10 @@ static inline void __devinit alloc_resource(struct pci_dev *dev, int idx)
                 r->flags |= IORESOURCE_UNSET;
                 r->end -= r->start;
                 r->start = 0;
+
+                return -EBUSY;
         }
+        return 0;
 }
 
 static void __init pcibios_allocate_resources(int pass)
@@ -1080,8 +1083,12 @@ static void __init pcibios_allocate_resources(int pass)
                                 disabled = !(command & PCI_COMMAND_IO);
                         else
                                 disabled = !(command & PCI_COMMAND_MEMORY);
-                        if (pass == disabled)
-                                alloc_resource(dev, idx);
+                        if (pass == disabled && alloc_resource(dev, idx)) {
+                                command &= ~(r->flags & (IORESOURCE_IO |
+                                                         IORESOURCE_MEM));
+                                pci_write_config_word(dev,
+                                                      PCI_COMMAND, command);
+                        }
                 }
                 if (pass)
                         continue;