io_apic.c

#ifdef CONFIG_SMP
void __init setup_ioapic_dest(void)
{
	int pin, ioapic = 0, irq, irq_entry;
	struct irq_desc *desc;
	const struct cpumask *mask;

	if (skip_ioapic_setup == 1)
		return;

#ifdef CONFIG_ACPI
	if (!acpi_disabled && acpi_ioapic) {
		ioapic = mp_find_ioapic(0);
		if (ioapic < 0)
			ioapic = 0;
	}
#endif

	for (pin = 0; pin < nr_ioapic_registers[ioapic]; pin++) {
		irq_entry = find_irq_entry(ioapic, pin, mp_INT);
		if (irq_entry == -1)
			continue;
		irq = pin_2_irq(irq_entry, ioapic, pin);

		desc = irq_to_desc(irq);

		/*
		 * Honour affinities which have been set in early boot
		 */
		if (desc->status &
		    (IRQ_NO_BALANCING | IRQ_AFFINITY_SET))
			mask = desc->affinity;
		else
			mask = apic->target_cpus();

		if (intr_remapping_enabled)
			set_ir_ioapic_affinity_irq_desc(desc, mask);
		else
			set_ioapic_affinity_irq_desc(desc, mask);
	}

}
#endif

#define IOAPIC_RESOURCE_NAME_SIZE 11

static struct resource *ioapic_resources;

static struct resource * __init ioapic_setup_resources(int nr_ioapics)
{
	unsigned long n;
	struct resource *res;
	char *mem;
	int i;

	if (nr_ioapics <= 0)
		return NULL;

	n = IOAPIC_RESOURCE_NAME_SIZE + sizeof(struct resource);
	n *= nr_ioapics;

	mem = alloc_bootmem(n);
	res = (void *)mem;

	mem += sizeof(struct resource) * nr_ioapics;

	for (i = 0; i < nr_ioapics; i++) {
		res[i].name = mem;
		res[i].flags = IORESOURCE_MEM | IORESOURCE_BUSY;
		snprintf(mem, IOAPIC_RESOURCE_NAME_SIZE, "IOAPIC %u", i);
		mem += IOAPIC_RESOURCE_NAME_SIZE;
	}

	ioapic_resources = res;

	return res;
}

void __init ioapic_init_mappings(void)
{
	unsigned long ioapic_phys, idx = FIX_IO_APIC_BASE_0;
	struct resource *ioapic_res;
	int i;

	ioapic_res = ioapic_setup_resources(nr_ioapics);
	for (i = 0; i < nr_ioapics; i++) {
		if (smp_found_config) {
			ioapic_phys = mp_ioapics[i].apicaddr;
#ifdef CONFIG_X86_32
			if (!ioapic_phys) {
				printk(KERN_ERR
				       "WARNING: bogus zero IO-APIC "
				       "address found in MPTABLE, "
				       "disabling IO/APIC support!\n");
				smp_found_config = 0;
				skip_ioapic_setup = 1;
				goto fake_ioapic_page;
			}
#endif
		} else {
#ifdef CONFIG_X86_32
fake_ioapic_page:
#endif
			ioapic_phys = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
			ioapic_phys = __pa(ioapic_phys);
		}
		set_fixmap_nocache(idx, ioapic_phys);
		apic_printk(APIC_VERBOSE, "mapped IOAPIC to %08lx (%08lx)\n",
			__fix_to_virt(idx) + (ioapic_phys & ~PAGE_MASK),
			ioapic_phys);
		idx++;

		ioapic_res->start = ioapic_phys;
		ioapic_res->end = ioapic_phys + IO_APIC_SLOT_SIZE - 1;
		ioapic_res++;
	}
}

void __init ioapic_insert_resources(void)
{
	int i;
	struct resource *r = ioapic_resources;

	if (!r) {
		if (nr_ioapics > 0)
			printk(KERN_ERR
				"IO APIC resources couldn't be allocated.\n");
		return;
	}

	for (i = 0; i < nr_ioapics; i++) {
		insert_resource(&iomem_resource, r);
		r++;
	}
}

int mp_find_ioapic(int gsi)
{
	int i = 0;

	/* Find the IOAPIC that manages this GSI. */
	for (i = 0; i < nr_ioapics; i++) {
		if ((gsi >= mp_gsi_routing[i].gsi_base)
		    && (gsi <= mp_gsi_routing[i].gsi_end))
			return i;
	}

	printk(KERN_ERR "ERROR: Unable to locate IOAPIC for GSI %d\n", gsi);
	return -1;
}

int mp_find_ioapic_pin(int ioapic, int gsi)
{
	if (WARN_ON(ioapic == -1))
		return -1;
	if (WARN_ON(gsi > mp_gsi_routing[ioapic].gsi_end))
		return -1;

	return gsi - mp_gsi_routing[ioapic].gsi_base;
}

static int bad_ioapic(unsigned long address)
{
	if (nr_ioapics >= MAX_IO_APICS) {
		printk(KERN_WARNING "WARING: Max # of I/O APICs (%d) exceeded "
		       "(found %d), skipping\n", MAX_IO_APICS, nr_ioapics);
		return 1;
	}
	if (!address) {
		printk(KERN_WARNING "WARNING: Bogus (zero) I/O APIC address"
		       " found in table, skipping!\n");
		return 1;
	}
	return 0;
}

void __init mp_register_ioapic(int id, u32 address, u32 gsi_base)
{
	int idx = 0;

	if (bad_ioapic(address))
		return;

	idx = nr_ioapics;

	mp_ioapics[idx].type = MP_IOAPIC;
	mp_ioapics[idx].flags = MPC_APIC_USABLE;
	mp_ioapics[idx].apicaddr = address;

	set_fixmap_nocache(FIX_IO_APIC_BASE_0 + idx, address);
	mp_ioapics[idx].apicid = io_apic_unique_id(id);
	mp_ioapics[idx].apicver = io_apic_get_version(idx);

	/*
	 * Build basic GSI lookup table to facilitate gsi->io_apic lookups
	 * and to prevent reprogramming of IOAPIC pins (PCI GSIs).
	 */
	mp_gsi_routing[idx].gsi_base = gsi_base;
	mp_gsi_routing[idx].gsi_end = gsi_base +
	    io_apic_get_redir_entries(idx);

	printk(KERN_INFO "IOAPIC[%d]: apic_id %d, version %d, address 0x%x, "
	       "GSI %d-%d\n", idx, mp_ioapics[idx].apicid,
	       mp_ioapics[idx].apicver, mp_ioapics[idx].apicaddr,
	       mp_gsi_routing[idx].gsi_base, mp_gsi_routing[idx].gsi_end);

	nr_ioapics++;
}