PCI quirk: TI XIO200a erroneously reports support for fast b2b transfers

This quirk will disable fast back to back transfer on the secondary bus
segment of the TI Bridge.

Signed-off-by: Gabe Black <gabe.black@ni.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

2 files changed, 20 insertions, 0 deletions

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 6099facecd79..efa6534a6593 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -670,6 +670,25 @@ static void __devinit quirk_vt8235_acpi(struct pci_dev *dev)
 }
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_VIA,     PCI_DEVICE_ID_VIA_8235, quirk_vt8235_acpi);
 
+/*
+ * TI XIO2000a PCIe-PCI Bridge erroneously reports it supports fast back-to-back:
+ *      Disable fast back-to-back on the secondary bus segment
+ */
+static void __devinit quirk_xio2000a(struct pci_dev *dev)
+{
+        struct pci_dev *pdev;
+        u16 command;
+
+        dev_warn(&dev->dev, "TI XIO2000a quirk detected; "
+                "secondary bus fast back-to-back transfers disabled\n");
+        list_for_each_entry(pdev, &dev->subordinate->devices, bus_list) {
+                pci_read_config_word(pdev, PCI_COMMAND, &command);
+                if (command & PCI_COMMAND_FAST_BACK)
+                        pci_write_config_word(pdev, PCI_COMMAND, command & ~PCI_COMMAND_FAST_BACK);
+        }
+}
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_TI, PCI_DEVICE_ID_TI_XIO2000A,
+                        quirk_xio2000a);
 
 #ifdef CONFIG_X86_IO_APIC 
 
diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
index da1fda8623e0..f490e7a7307a 100644
--- a/include/linux/pci_ids.h
+++ b/include/linux/pci_ids.h
@@ -776,6 +776,7 @@
 #define PCI_DEVICE_ID_TI_X515           0x8036
 #define PCI_DEVICE_ID_TI_XX12           0x8039
 #define PCI_DEVICE_ID_TI_XX12_FM        0x803b
+#define PCI_DEVICE_ID_TI_XIO2000A       0x8231
 #define PCI_DEVICE_ID_TI_1130           0xac12
 #define PCI_DEVICE_ID_TI_1031           0xac13
 #define PCI_DEVICE_ID_TI_1131           0xac15