path: root/arch/i386/pci/irq.c

/*
 *	Low-Level PCI Support for PC -- Routing of Interrupts
 *
 *	(c) 1999--2000 Martin Mares <mj@ucw.cz>
 */

#include <linux/config.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/dmi.h>
#include <asm/io.h>
#include <asm/smp.h>
#include <asm/io_apic.h>
#include <asm/hw_irq.h>
#include <linux/acpi.h>

#include "pci.h"

#define PIRQ_SIGNATURE	(('$' << 0) + ('P' << 8) + ('I' << 16) + ('R' << 24))
#define PIRQ_VERSION 0x0100

static int broken_hp_bios_irq9;
static int acer_tm360_irqrouting;

static struct irq_routing_table *pirq_table;

static int pirq_enable_irq(struct pci_dev *dev);

/*
 * Never use: 0, 1, 2 (timer, keyboard, and cascade)
 * Avoid using: 13, 14 and 15 (FP error and IDE).
 * Penalize: 3, 4, 6, 7, 12 (known ISA uses: serial, floppy, parallel and mouse)
 */
unsigned int pcibios_irq_mask = 0xfff8;

static int pirq_penalty[16] = {
	1000000, 1000000, 1000000, 1000, 1000, 0, 1000, 1000,
	0, 0, 0, 0, 1000, 100000, 100000, 100000
};

struct irq_router {
	char *name;
	u16 vendor, device;
	int (*get)(struct pci_dev *router, struct pci_dev *dev, int pirq);
	int (*set)(struct pci_dev *router, struct pci_dev *dev, int pirq, int new);
};

struct irq_router_handler {
	u16 vendor;
	int (*probe)(struct irq_router *r, struct pci_dev *router, u16 device);
};

int (*pcibios_enable_irq)(struct pci_dev *dev) = NULL;

/*
 *  Search 0xf0000 -- 0xfffff for the PCI IRQ Routing Table.
 */

static struct irq_routing_table * __init pirq_find_routing_table(void)
{
	u8 *addr;
	struct irq_routing_table *rt;
	int i;
	u8 sum;

	for(addr = (u8 *) __va(0xf0000); addr < (u8 *) __va(0x100000); addr += 16) {
		rt = (struct irq_routing_table *) addr;
		if (rt->signature != PIRQ_SIGNATURE ||
		    rt->version != PIRQ_VERSION ||
		    rt->size % 16 ||
		    rt->size < sizeof(struct irq_routing_table))
			continue;
		sum = 0;
		for(i=0; i<rt->size; i++)
			sum += addr[i];
		if (!sum) {
			DBG("PCI: Interrupt Routing Table found at 0x%p\n", rt);
			return rt;
		}
	}
	return NULL;
}

/*
 *  If we have a IRQ routing table, use it to search for peer host
 *  bridges.  It's a gross hack, but since there are no other known
 *  ways how to get a list of buses, we have to go this way.
 */

static void __init pirq_peer_trick(void)
{
	struct irq_routing_table *rt = pirq_table;
	u8 busmap[256];
	int i;
	struct irq_info *e;

	memset(busmap, 0, sizeof(busmap));
	for(i=0; i < (rt->size - sizeof(struct irq_routing_table)) / sizeof(struct irq_info); i++) {
		e = &rt->slots[i];
#ifdef DEBUG
		{
			int j;
			DBG("%02x:%02x slot=%02x", e->bus, e->devfn/8, e->slot);
			for(j=0; j<4; j++)
				DBG(" %d:%02x/%04x", j, e->irq[<