65 lines
1.6 KiB
C
65 lines
1.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Support routines for initializing a PCI subsystem
|
|
*
|
|
* Extruded from code written by
|
|
* Dave Rusling (david.rusling@reo.mts.dec.com)
|
|
* David Mosberger (davidm@cs.arizona.edu)
|
|
* David Miller (davem@redhat.com)
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/pci.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/ioport.h>
|
|
#include <linux/cache.h>
|
|
#include "pci.h"
|
|
|
|
void pci_assign_irq(struct pci_dev *dev)
|
|
{
|
|
u8 pin;
|
|
u8 slot = -1;
|
|
int irq = 0;
|
|
struct pci_host_bridge *hbrg = pci_find_host_bridge(dev->bus);
|
|
|
|
if (!(hbrg->map_irq)) {
|
|
pci_dbg(dev, "runtime IRQ mapping not provided by arch\n");
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* 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 because 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) {
|
|
/* Follow the chain of bridges, swizzling as we go. */
|
|
if (hbrg->swizzle_irq)
|
|
slot = (*(hbrg->swizzle_irq))(dev, &pin);
|
|
|
|
/*
|
|
* If a swizzling function is not used, map_irq() must
|
|
* ignore slot.
|
|
*/
|
|
irq = (*(hbrg->map_irq))(dev, slot, pin);
|
|
if (irq == -1)
|
|
irq = 0;
|
|
}
|
|
dev->irq = irq;
|
|
|
|
pci_dbg(dev, "assign 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.
|
|
*/
|
|
pci_write_config_byte(dev, PCI_INTERRUPT_LINE, irq);
|
|
}
|