linux/drivers/pci/setup-irq.c
Thierry Reding 8885b7b637 PCI: Provide a default pcibios_update_irq()
Most architectures implement this in exactly the same way. Instead of
having each architecture duplicate this function, provide a single
implementation in the core and make it a weak symbol so that it can be
overridden on architectures where it is required.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2012-09-18 17:28:21 -06:00

69 lines
1.7 KiB
C

/*
* 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/init.h>
#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);
}