ACPI/PCI: PCI extended config _OSC support called when root bridge added

The _OSC capability OSC_EXT_PCI_CONFIG_SUPPORT is set when the root
bridge is added with pci_acpi_osc_support() if we can access PCI
extended config space.

This adds the function pci_ext_cfg_avail which returns true if we can
access PCI extended config space (offset greater than 0xff). It
currently only returns false if arch=x86 and raw_pci_ext_ops is not set
(which might happen if pci=nommcfg is set on the kernel command-line).

Signed-off-by: Andrew Patterson <andrew.patterson@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

2 files changed, 21 insertions, 2 deletions

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index de4d57114fe4..96e68e841539 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -194,7 +194,7 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
         unsigned long long value = 0;
         acpi_handle handle = NULL;
         struct acpi_device *child;
-        u32 flags;
+        u32 flags, base_flags;
 
 
         if (!device)
@@ -216,7 +216,7 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
          * All supported architectures that use ACPI have support for
          * PCI domains, so we indicate this in _OSC support capabilities.
          */
-        flags = OSC_PCI_SEGMENT_GROUPS_SUPPORT;
+        flags = base_flags = OSC_PCI_SEGMENT_GROUPS_SUPPORT;
         pci_acpi_osc_support(device->handle, flags);
 
         /* 
@@ -344,6 +344,12 @@ static int __devinit acpi_pci_root_add(struct acpi_device *device)
         list_for_each_entry(child, &device->children, node)
                 acpi_pci_bridge_scan(child);
 
+        /* Indicate support for various _OSC capabilities. */
+        if (pci_ext_cfg_avail(root->bus->self))
+                flags |= OSC_EXT_PCI_CONFIG_SUPPORT;
+        if (flags != base_flags)
+                pci_acpi_osc_support(device->handle, flags);
+
       end:
         if (result) {
                 if (!list_empty(&root->node))
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 3c2fa2fdc9cd..48fa860276d4 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2084,6 +2084,19 @@ static void __devinit pci_no_domains(void)
 #endif
 }
 
+/**
+ * pci_ext_cfg_enabled - can we access extended PCI config space?
+ * @dev: The PCI device of the root bridge.
+ *
+ * Returns 1 if we can access PCI extended config space (offsets
+ * greater than 0xff). This is the default implementation. Architecture
+ * implementations can override this.
+ */
+int __attribute__ ((weak)) pci_ext_cfg_avail(struct pci_dev *dev)
+{
+        return 1;
+}
+
 static int __devinit pci_init(void)
 {
         struct pci_dev *dev = NULL;