release/src-rt-6.x.4708/linux/linux-2.6.36/drivers/pci/setup-irq.c

   1 /* Modified by Broadcom Corp. Portions Copyright (c) Broadcom Corp, 2012. */
   2 /*
   3  *      drivers/pci/setup-irq.c
   4  *
   5  * Extruded from code written by
   6  *      Dave Rusling (david.rusling@reo.mts.dec.com)
   7  *      David Mosberger (davidm@cs.arizona.edu)
   8  *      David Miller (davem@redhat.com)
   9  *
  10  * Support routines for initializing a PCI subsystem.
  11  */
  12
  13
  14 #include <linux/init.h>
  15 #include <linux/kernel.h>
  16 #include <linux/pci.h>
  17 #include <linux/errno.h>
  18 #include <linux/ioport.h>
  19 #include <linux/cache.h>
  20
  21
  22 static void __init
  23 pdev_fixup_irq(struct pci_dev *dev,
  24                u8 (*swizzle)(struct pci_dev *, u8 *),
  25                int (*map_irq)(struct pci_dev *, u8, u8))
  26 {
  27         u8 pin, slot;
  28         int irq = 0;
  29
  30 #ifdef CONFIG_BCM47XX
  31         if (pci_domain_nr(dev->bus) == 0)
  32                 return;
  33 #endif
  34
  35         /* If this device is not on the primary bus, we need to figure out
  36            which interrupt pin it will come in on.   We know which slot it
  37            will come in on 'cos that slot is where the bridge is.   Each
  38            time the interrupt line passes through a PCI-PCI bridge we must
  39            apply the swizzle function.  */
  40
  41         pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
  42         /* Cope with illegal. */
  43         if (pin > 4)
  44                 pin = 1;
  45
  46         if (pin != 0) {
  47                 /* Follow the chain of bridges, swizzling as we go.  */
  48                 slot = (*swizzle)(dev, &pin);
  49
  50                 irq = (*map_irq)(dev, slot, pin);
  51                 if (irq == -1)
  52                         irq = 0;
  53         }
  54         dev->irq = irq;
  55
  56         dev_dbg(&dev->dev, "fixup irq: got %d\n", 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
  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 = NULL;
  68         for_each_pci_dev(dev)
  69                 pdev_fixup_irq(dev, swizzle, map_irq);
  70 }