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path: root/drivers/pci/setup-irq.c
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Diffstat (limited to 'drivers/pci/setup-irq.c')
-rw-r--r--drivers/pci/setup-irq.c68
1 files changed, 68 insertions, 0 deletions
diff --git a/drivers/pci/setup-irq.c b/drivers/pci/setup-irq.c
new file mode 100644
index 000000000..95c225be4
--- /dev/null
+++ b/drivers/pci/setup-irq.c
@@ -0,0 +1,68 @@
+/*
+ * drivers/pci/setup-irq.c
+ *
+ * Extruded from code written by
+ * Dave Rusling (david.rusling@reo.mts.dec.com)
+ * David Mosberger (davidm@cs.arizona.edu)
+ * David Miller (davem@redhat.com)
+ *
+ * Support routines for initializing a PCI subsystem.
+ */
+
+
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include <linux/errno.h>
+#include <linux/ioport.h>
+#include <linux/cache.h>
+
+void __weak pcibios_update_irq(struct pci_dev *dev, int irq)
+{
+ dev_dbg(&dev->dev, "assigning IRQ %02d\n", irq);
+ pci_write_config_byte(dev, PCI_INTERRUPT_LINE, irq);
+}
+
+static void pdev_fixup_irq(struct pci_dev *dev,
+ u8 (*swizzle)(struct pci_dev *, u8 *),
+ int (*map_irq)(const struct pci_dev *, u8, u8))
+{
+ u8 pin, slot;
+ int irq = 0;
+
+ /* If this device is not on the primary bus, we need to figure out
+ which interrupt pin it will come in on. We know which slot it
+ will come in on 'cos that slot is where the bridge is. Each
+ time the interrupt line passes through a PCI-PCI bridge we must
+ apply the swizzle function. */
+
+ pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
+ /* Cope with illegal. */
+ if (pin > 4)
+ pin = 1;
+
+ if (pin != 0) {
+ /* Follow the chain of bridges, swizzling as we go. */
+ slot = (*swizzle)(dev, &pin);
+
+ irq = (*map_irq)(dev, slot, pin);
+ if (irq == -1)
+ irq = 0;
+ }
+ dev->irq = irq;
+
+ dev_dbg(&dev->dev, "fixup irq: got %d\n", dev->irq);
+
+ /* Always tell the device, so the driver knows what is
+ the real IRQ to use; the device does not use it. */
+ pcibios_update_irq(dev, irq);
+}
+
+void pci_fixup_irqs(u8 (*swizzle)(struct pci_dev *, u8 *),
+ int (*map_irq)(const struct pci_dev *, u8, u8))
+{
+ struct pci_dev *dev = NULL;
+
+ for_each_pci_dev(dev)
+ pdev_fixup_irq(dev, swizzle, map_irq);
+}
+EXPORT_SYMBOL_GPL(pci_fixup_irqs);