PCI: quirks: set 'En' bit of MSI Mapping for devices onHT-based nvidia platform

According to HT spec, to get message interrupt from devices mapped to HT
interrupt message, the 'En' bit of MSI Mapping capability need to be set.
The patch do this setting in quirks code for the devices on HT-based nvidia
platform.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NAndy Currid <acurrid@nvidia.com>
Signed-off-by: NPeer Chen <pchen@nvidia.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/pci/quirks.c

@@ -1778,6 +1778,68 @@ static void __devinit quirk_nvidia_ck804_msi_ht_cap(struct pci_dev *dev)
 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) {
+			dev_info(&dev->dev, "Enabling HT MSI Mapping\n");
+
+			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...
+	 */
+	host_bridge = pci_get_bus_and_slot(0, PCI_DEVFN(0, 0));
+	if (host_bridge == NULL) {
+		dev_warn(&dev->dev,
+			 "nv_msi_ht_cap_quirk didn't locate host bridge\n");
+		return;
+	}
+
+	pos = pci_find_ht_capability(host_bridge, HT_CAPTYPE_SLAVE);
+	if (pos != 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) {
+			dev_info(&dev->dev, "Quirk disabling HT MSI mapping");
+			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;