setup-irq.c revision 19c38de88a80913351fcacefdb461cc0b585fa87 
1/*
2 *	drivers/pci/setup-irq.c
3 *
4 * Extruded from code written by
5 *      Dave Rusling (david.rusling@reo.mts.dec.com)
6 *      David Mosberger (davidm@cs.arizona.edu)
7 *	David Miller (davem@redhat.com)
8 *
9 * Support routines for initializing a PCI subsystem.
10 */
11
12
13#include <linux/init.h>
14#include <linux/kernel.h>
15#include <linux/pci.h>
16#include <linux/errno.h>
17#include <linux/ioport.h>
18#include <linux/cache.h>
19
20
21static void __init
22pdev_fixup_irq(struct pci_dev *dev,
23	       u8 (*swizzle)(struct pci_dev *, u8 *),
24	       int (*map_irq)(struct pci_dev *, u8, u8))
25{
26	u8 pin, slot;
27	int irq = 0;
28
29	/* If this device is not on the primary bus, we need to figure out
30	   which interrupt pin it will come in on.   We know which slot it
31	   will come in on 'cos that slot is where the bridge is.   Each
32	   time the interrupt line passes through a PCI-PCI bridge we must
33	   apply the swizzle function.  */
34
35	pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
36	/* Cope with illegal. */
37	if (pin > 4)
38		pin = 1;
39
40	if (pin != 0) {
41		/* Follow the chain of bridges, swizzling as we go.  */
42		slot = (*swizzle)(dev, &pin);
43
44		irq = (*map_irq)(dev, slot, pin);
45		if (irq == -1)
46			irq = 0;
47	}
48	dev->irq = irq;
49
50	pr_debug("PCI: fixup irq: (%s) got %d\n",
51		kobject_name(&dev->dev.kobj), dev->irq);
52
53	/* Always tell the device, so the driver knows what is
54	   the real IRQ to use; the device does not use it. */
55	pcibios_update_irq(dev, irq);
56}
57
58void __init
59pci_fixup_irqs(u8 (*swizzle)(struct pci_dev *, u8 *),
60	       int (*map_irq)(struct pci_dev *, u8, u8))
61{
62	struct pci_dev *dev = NULL;
63	while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
64		pdev_fixup_irq(dev, swizzle, map_irq);
65	}
66}
67