[PATCH]quirks: set 'En' bit of MSI Mapping for devices on HT-based nvidia platform

["peerchen" <peerchen@gmail.com>]

Signed-off-by: Andy Currid <acurrid@nvidia.com>
Signed-off-by: Peer Chen <pchen@nvidia.com>

---
--- linux-2.6.24-rc7/drivers/pci/quirks.c.orig	2008-01-09 16:37:36.000000000 -0500
+++ linux-2.6.24-rc7/drivers/pci/quirks.c	2008-01-10 15:03:09.000000000 -0500
@@ -1705,6 +1705,70 @@ static void __devinit quirk_nvidia_ck804
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_CK804_PCIE,
 			quirk_nvidia_ck804_msi_ht_cap);
 
+/*
+ *  Force enable MSI mapping capability on HT bridges  */
+static inline void ht_enable_msi_mapping(struct pci_dev *dev)
+{
+	int pos, ttl = 48;
+
+	pos = pci_find_ht_capability(dev, HT_CAPTYPE_MSI_MAPPING);
+	while (pos && ttl--) {
+		u8 flags;
+
+		if (pci_read_config_byte(dev, pos + HT_MSI_FLAGS, &flags) == 0) {
+			printk(KERN_INFO "PCI: Enabling HT MSI Mapping on %s\n",
+						dev->dev.bus_id);
+
+			pci_write_config_byte(dev, pos + HT_MSI_FLAGS,
+					      flags | HT_MSI_FLAGS_ENABLE);
+		}
+		pos = pci_find_next_ht_capability(dev, pos,
+						  HT_CAPTYPE_MSI_MAPPING);
+	}
+}
+
+static void __devinit nv_msi_ht_cap_quirk(struct pci_dev *dev) {
+
+	struct pci_dev *host_bridge;
+	int pos, ttl = 48;
+	
+	/* HT MSI mapping should be disabled on devices that are below
+	 * a non-Hypertransport host bridge. Locate the host bridge...
+ 	 */
+
+	if ((host_bridge = pci_get_bus_and_slot(0, PCI_DEVFN(0,0))) == NULL) {
+		printk(KERN_WARNING
+			"PCI: nv_msi_ht_cap_quirk didn't locate host bridge\n");
+		return;
+	}
+
+	if ((pos = pci_find_ht_capability(host_bridge, HT_CAPTYPE_SLAVE)) != 0) {
+		/* Host bridge is to HT */
+		ht_enable_msi_mapping(dev);
+		return;
+	}
+
+	/* Host bridge is not to HT, disable HT MSI mapping on this device */
+
+	pos = pci_find_ht_capability(dev, HT_CAPTYPE_MSI_MAPPING);
+	while (pos && ttl--) {
+		u8 flags;
+
+		if (pci_read_config_byte(dev, pos + HT_MSI_FLAGS, &flags) == 0) {
+			printk(KERN_INFO "PCI: Quirk disabling HT MSI mapping on %s\n",
+			       pci_name(dev));
+
+			pci_write_config_byte(dev, pos + HT_MSI_FLAGS,
+					      flags & ~HT_MSI_FLAGS_ENABLE);
+		}
+		pos = pci_find_next_ht_capability(dev, pos,
+						  HT_CAPTYPE_MSI_MAPPING);
+	}
+}
+
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID,
+							nv_msi_ht_cap_quirk);
+
 static void __devinit quirk_msi_intx_disable_bug(struct pci_dev *dev)
 {
 	dev->dev_flags |= PCI_DEV_FLAGS_MSI_INTX_DISABLE_BUG;
-