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>

arch/x86/pci/common.c

@@ -562,6 +562,14 @@ void pcibios_disable_device (struct pci_dev *dev)
 		pcibios_disable_irq(dev);
 }
 
+int pci_ext_cfg_avail(struct pci_dev *dev)
+{
+	if (raw_pci_ext_ops)
+		return 1;
+	else
+		return 0;
+}
+
 struct pci_bus * __devinit pci_scan_bus_on_node(int busno, struct pci_ops *ops, int node)
 {
 	struct pci_bus *bus = NULL;

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))

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;

include/linux/pci.h

@@ -1140,6 +1140,8 @@ static inline void pci_mmcfg_early_init(void) { }
 static inline void pci_mmcfg_late_init(void) { }
 #endif
 
+int pci_ext_cfg_avail(struct pci_dev *dev);
+
 #ifdef CONFIG_HAS_IOMEM
 static inline void __iomem *pci_ioremap_bar(struct pci_dev *pdev, int bar)
 {