1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Support routines for initializing a PCI subsystem
 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
 
 
11#include <linux/kernel.h>
12#include <linux/pci.h>
13#include <linux/errno.h>
14#include <linux/ioport.h>
15#include <linux/cache.h>
16#include "pci.h"
17
18void pci_assign_irq(struct pci_dev *dev)
 
 
 
 
 
 
 
 
 
19{
20	u8 pin;
21	u8 slot = -1;
22	int irq = 0;
23	struct pci_host_bridge *hbrg = pci_find_host_bridge(dev->bus);
24
25	if (!(hbrg->map_irq)) {
26		pci_dbg(dev, "runtime IRQ mapping not provided by arch\n");
27		return;
28	}
 
29
30	/*
31	 * If this device is not on the primary bus, we need to figure out
32	 * which interrupt pin it will come in on. We know which slot it
33	 * will come in on because that slot is where the bridge is. Each
34	 * time the interrupt line passes through a PCI-PCI bridge we must
35	 * apply the swizzle function.
36	 */
37	pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
38	/* Cope with illegal. */
39	if (pin > 4)
40		pin = 1;
41
42	if (pin) {
43		/* Follow the chain of bridges, swizzling as we go. */
44		if (hbrg->swizzle_irq)
45			slot = (*(hbrg->swizzle_irq))(dev, &pin);
46
47		/*
48		 * If a swizzling function is not used, map_irq() must
49		 * ignore slot.
50		 */
51		irq = (*(hbrg->map_irq))(dev, slot, pin);
52		if (irq == -1)
53			irq = 0;
54	}
55	dev->irq = irq;
56
57	pci_dbg(dev, "assign IRQ: got %d\n", dev->irq);
58
59	/*
60	 * Always tell the device, so the driver knows what is the real IRQ
61	 * to use; the device does not use it.
62	 */
63	pci_write_config_byte(dev, PCI_INTERRUPT_LINE, irq);
 
 
 
 
 
 
 
64}

 
 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
20void __weak pcibios_update_irq(struct pci_dev *dev, int irq)
21{
22	dev_dbg(&dev->dev, "assigning IRQ %02d\n", irq);
23	pci_write_config_byte(dev, PCI_INTERRUPT_LINE, irq);
24}
25
26static void
27pdev_fixup_irq(struct pci_dev *dev,
28	       u8 (*swizzle)(struct pci_dev *, u8 *),
29	       int (*map_irq)(const struct pci_dev *, u8, u8))
30{
31	u8 pin, slot;
 
32	int irq = 0;
 
33
34	/* If this device is not on the primary bus, we need to figure out
35	   which interrupt pin it will come in on.   We know which slot it
36	   will come in on 'cos that slot is where the bridge is.   Each
37	   time the interrupt line passes through a PCI-PCI bridge we must
38	   apply the swizzle function.  */
39
 
 
 
 
 
 
 
40	pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
41	/* Cope with illegal. */
42	if (pin > 4)
43		pin = 1;
44
45	if (pin != 0) {
46		/* Follow the chain of bridges, swizzling as we go.  */
47		slot = (*swizzle)(dev, &pin);
48
49		irq = (*map_irq)(dev, slot, pin);
 
 
 
 
 
50		if (irq == -1)
51			irq = 0;
52	}
53	dev->irq = irq;
54
55	dev_dbg(&dev->dev, "fixup irq: got %d\n", dev->irq);
56
57	/* Always tell the device, so the driver knows what is
58	   the real IRQ to use; the device does not use it. */
59	pcibios_update_irq(dev, irq);
60}
61
62void
63pci_fixup_irqs(u8 (*swizzle)(struct pci_dev *, u8 *),
64	       int (*map_irq)(const struct pci_dev *, u8, u8))
65{
66	struct pci_dev *dev = NULL;
67	for_each_pci_dev(dev)
68		pdev_fixup_irq(dev, swizzle, map_irq);
69}