Merge branch 'pci/misc' into next

* pci/misc:
  PCI: Fix return value from pci_user_{read,write}_config_*()
  PCI: Turn pcibios_penalize_isa_irq() into a weak function
  PCI: Test for std config alias when testing extended config space

1 files changed, 38 insertions, 1 deletions

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 36f1fd174b07..2bbf5221afb3 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -994,6 +994,43 @@ void set_pcie_hotplug_bridge(struct pci_dev *pdev)
 
 
 /**
+ * pci_ext_cfg_is_aliased - is ext config space just an alias of std config?
+ * @dev: PCI device
+ *
+ * PCI Express to PCI/PCI-X Bridge Specification, rev 1.0, 4.1.4 says that
+ * when forwarding a type1 configuration request the bridge must check that
+ * the extended register address field is zero.  The bridge is not permitted
+ * to forward the transactions and must handle it as an Unsupported Request.
+ * Some bridges do not follow this rule and simply drop the extended register
+ * bits, resulting in the standard config space being aliased, every 256
+ * bytes across the entire configuration space.  Test for this condition by
+ * comparing the first dword of each potential alias to the vendor/device ID.
+ * Known offenders:
+ *   ASM1083/1085 PCIe-to-PCI Reversible Bridge (1b21:1080, rev 01 & 03)
+ *   AMD/ATI SBx00 PCI to PCI Bridge (1002:4384, rev 40)
+ */
+static bool pci_ext_cfg_is_aliased(struct pci_dev *dev)
+{
+#ifdef CONFIG_PCI_QUIRKS
+	int pos;
+	u32 header, tmp;
+
+	pci_read_config_dword(dev, PCI_VENDOR_ID, &header);
+
+	for (pos = PCI_CFG_SPACE_SIZE;
+	     pos < PCI_CFG_SPACE_EXP_SIZE; pos += PCI_CFG_SPACE_SIZE) {
+		if (pci_read_config_dword(dev, pos, &tmp) != PCIBIOS_SUCCESSFUL
+		    || header != tmp)
+			return false;
+	}
+
+	return true;
+#else
+	return false;
+#endif
+}
+
+/**
  * pci_cfg_space_size - get the configuration space size of the PCI device.
  * @dev: PCI device
  *
@@ -1011,7 +1048,7 @@ static int pci_cfg_space_size_ext(struct pci_dev *dev)
 
 	if (pci_read_config_dword(dev, pos, &status) != PCIBIOS_SUCCESSFUL)
 		goto fail;
-	if (status == 0xffffffff)
+	if (status == 0xffffffff || pci_ext_cfg_is_aliased(dev))
 		goto fail;
 
 	return PCI_CFG_SPACE_EXP_SIZE;