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-rw-r--r--drivers/pci/pci.c16
-rw-r--r--include/linux/pci.h1
2 files changed, 16 insertions, 1 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index bd52ca4c289..d4d71fae623 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;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index bfcb39ca887..58357d14f94 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -532,6 +532,7 @@ int __must_check pci_bus_add_device(struct pci_dev *dev);
void pci_read_bridge_bases(struct pci_bus *child);
struct resource *pci_find_parent_resource(const struct pci_dev *dev,
struct resource *res);
+u8 pci_swizzle_interrupt_pin(struct pci_dev *dev, u8 pin);
int pci_get_interrupt_pin(struct pci_dev *dev, struct pci_dev **bridge);
extern struct pci_dev *pci_dev_get(struct pci_dev *dev);
extern void pci_dev_put(struct pci_dev *dev);