X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=drivers%2Fpci%2Fpci.c;h=d4d71fae623352143a5691e72c25871bc6684818;hb=57c2cf71c12318b72ebaa5720d210476b6bac4d4;hp=bd52ca4c28933804dda155941c13e4c01f99095d;hpb=12b955ff63db0b75cfc2d4939696c57b31891ec6;p=firefly-linux-kernel-4.4.55.git

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index bd52ca4c2893..d4d71fae6233 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1366,6 +1366,20 @@ void pci_enable_ari(struct pci_dev *dev)
 	bridge->ari_enabled = 1;
 }
 
+/**
+ * pci_swizzle_interrupt_pin - swizzle INTx for device behind bridge
+ * @dev: the PCI device
+ * @pin: the INTx pin (1=INTA, 2=INTB, 3=INTD, 4=INTD)
+ *
+ * Perform INTx swizzling for a device behind one level of bridge.  This is
+ * required by section 9.1 of the PCI-to-PCI bridge specification for devices
+ * behind bridges on add-in cards.
+ */
+u8 pci_swizzle_interrupt_pin(struct pci_dev *dev, u8 pin)
+{
+	return (((pin - 1) + PCI_SLOT(dev->devfn)) % 4) + 1;
+}
+
 int
 pci_get_interrupt_pin(struct pci_dev *dev, struct pci_dev **bridge)
 {
@@ -1376,7 +1390,7 @@ pci_get_interrupt_pin(struct pci_dev *dev, struct pci_dev **bridge)
 		return -1;
 
 	while (dev->bus->self) {
-		pin = (((pin - 1) + PCI_SLOT(dev->devfn)) % 4) + 1;
+		pin = pci_swizzle_interrupt_pin(dev, pin);
 		dev = dev->bus->self;
 	}
 	*bridge = dev;