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
21 #define DEBUG_CONFIG 0
22 #if DEBUG_CONFIG
23 # define DBGC(args) printk args
24 #else
25 # define DBGC(args)
26 #endif
27
28
29 static void __init
pdev_fixup_irq(struct pci_dev * dev,u8 (* swizzle)(struct pci_dev *,u8 *),int (* map_irq)(struct pci_dev *,u8,u8))30 pdev_fixup_irq(struct pci_dev *dev,
31 u8 (*swizzle)(struct pci_dev *, u8 *),
32 int (*map_irq)(struct pci_dev *, u8, u8))
33 {
34 u8 pin, slot;
35 int irq;
36
37 /* If this device is not on the primary bus, we need to figure out
38 which interrupt pin it will come in on. We know which slot it
39 will come in on 'cos that slot is where the bridge is. Each
40 time the interrupt line passes through a PCI-PCI bridge we must
41 apply the swizzle function. */
42
43 pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
44 /* Cope with 0 and illegal. */
45 if (pin == 0 || pin > 4)
46 pin = 1;
47
48 /* Follow the chain of bridges, swizzling as we go. */
49 slot = (*swizzle)(dev, &pin);
50
51 irq = (*map_irq)(dev, slot, pin);
52 if (irq == -1)
53 irq = 0;
54 dev->irq = irq;
55
56 DBGC((KERN_ERR "PCI fixup irq: (%s) got %d\n", dev->name, dev->irq));
57
58 /* Always tell the device, so the driver knows what is
59 the real IRQ to use; the device does not use it. */
60 pcibios_update_irq(dev, irq);
61 }
62
63 void __init
pci_fixup_irqs(u8 (* swizzle)(struct pci_dev *,u8 *),int (* map_irq)(struct pci_dev *,u8,u8))64 pci_fixup_irqs(u8 (*swizzle)(struct pci_dev *, u8 *),
65 int (*map_irq)(struct pci_dev *, u8, u8))
66 {
67 struct pci_dev *dev;
68 pci_for_each_dev(dev) {
69 pdev_fixup_irq(dev, swizzle, map_irq);
70 }
71 }
72