pci-irq.c

讲述linux的初始化过程

}

static struct irq_router pirq_bios_router =
	{ "BIOS", 0, 0, NULL, pirq_bios_set };

#endif

static struct irq_router pirq_routers[] = {
	{ "PIIX", PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371FB_0, pirq_piix_get, pirq_piix_set },
	{ "PIIX", PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371SB_0, pirq_piix_get, pirq_piix_set },
	{ "PIIX", PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371AB_0, pirq_piix_get, pirq_piix_set },
	{ "PIIX", PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371MX,   pirq_piix_get, pirq_piix_set },
	{ "PIIX", PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82443MX_0, pirq_piix_get, pirq_piix_set },

	{ "ALI", PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533, pirq_ali_get, pirq_ali_set },

	{ "VIA", PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C586_0, pirq_via_get, pirq_via_set },
	{ "VIA", PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C596, pirq_via_get, pirq_via_set },
	{ "VIA", PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_82C686, pirq_via_get, pirq_via_set },

	{ "OPTI", PCI_VENDOR_ID_OPTI, PCI_DEVICE_ID_OPTI_82C700, pirq_opti_get, pirq_opti_set },

	{ "NatSemi", PCI_VENDOR_ID_CYRIX, PCI_DEVICE_ID_CYRIX_5520, pirq_cyrix_get, pirq_cyrix_set },
	{ "SIS", PCI_VENDOR_ID_SI, PCI_DEVICE_ID_SI_503, pirq_sis_get, pirq_sis_set },
	{ "VLSI 82C534", PCI_VENDOR_ID_VLSI, PCI_DEVICE_ID_VLSI_82C534, pirq_vlsi_get, pirq_vlsi_set },
	{ "ServerWorks", PCI_VENDOR_ID_SERVERWORKS, PCI_DEVICE_ID_SERVERWORKS_OSB4,
	  pirq_serverworks_get, pirq_serverworks_set },

	{ "default", 0, 0, NULL, NULL }
};

static struct irq_router *pirq_router;
static struct pci_dev *pirq_router_dev;

static void __init pirq_find_router(void)
{
	struct irq_routing_table *rt = pirq_table;
	struct irq_router *r;

#ifdef CONFIG_PCI_BIOS
	if (!rt->signature) {
		printk("PCI: Using BIOS for IRQ routing\n");
		pirq_router = &pirq_bios_router;
		return;
	}
#endif
	/* fall back to default router if nothing else found */
	pirq_router = pirq_routers + sizeof(pirq_routers) / sizeof(pirq_routers[0]) - 1;

	pirq_router_dev = pci_find_slot(rt->rtr_bus, rt->rtr_devfn);
	if (!pirq_router_dev) {
		DBG("PCI: Interrupt router not found at %02x:%02x\n", rt->rtr_bus, rt->rtr_devfn);
		return;
	}

	for(r=pirq_routers; r->vendor; r++) {
		/* Exact match against router table entry? Use it! */
		if (r->vendor == rt->rtr_vendor && r->device == rt->rtr_device) {
			pirq_router = r;
			break;
		}
		/* Match against router device entry? Use it as a fallback */
		if (r->vendor == pirq_router_dev->vendor && r->device == pirq_router_dev->device) {
			pirq_router = r;
		}
	}
	printk("PCI: Using IRQ router %s [%04x/%04x] at %s\n",
		pirq_router->name,
		pirq_router_dev->vendor,
		pirq_router_dev->device,
		pirq_router_dev->slot_name);
}

static struct irq_info *pirq_get_info(struct pci_dev *dev)
{
	struct irq_routing_table *rt = pirq_table;
	int entries = (rt->size - sizeof(struct irq_routing_table)) / sizeof(struct irq_info);
	struct irq_info *info;

	for (info = rt->slots; entries--; info++)
		if (info->bus == dev->bus->number && PCI_SLOT(info->devfn) == PCI_SLOT(dev->devfn))
			return info;
	return NULL;
}

static void pcibios_test_irq_handler(int irq, void *dev_id, struct pt_regs *regs)
{
}

static int pcibios_lookup_irq(struct pci_dev *dev, int assign)
{
	u8 pin;
	struct irq_info *info;
	int i, pirq, newirq;
	int irq = 0;
	u32 mask;
	struct irq_router *r = pirq_router;
	struct pci_dev *dev2;
	char *msg = NULL;

	if (!pirq_table)
		return 0;

	/* Find IRQ routing entry */
	pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
	if (!pin) {
		DBG(" -> no interrupt pin\n");
		return 0;
	}
	pin = pin - 1;
	
	DBG("IRQ for %s:%d", dev->slot_name, pin);
	info = pirq_get_info(dev);
	if (!info) {
		DBG(" -> not found in routing table\n");
		return 0;
	}
	pirq = info->irq[pin].link;
	mask = info->irq[pin].bitmap;
	if (!pirq) {
		DBG(" -> not routed\n");
		return 0;
	}
	DBG(" -> PIRQ %02x, mask %04x, excl %04x", pirq, mask, pirq_table->exclusive_irqs);
	mask &= pcibios_irq_mask;

	/*
	 * Find the best IRQ to assign: use the one
	 * reported by the device if possible.
	 */
	newirq = dev->irq;
	if (!newirq && assign) {
		for (i = 0; i < 16; i++) {
			if (!(mask & (1 << i)))
				continue;
			if (pirq_penalty[i] < pirq_penalty[newirq] &&
			    !request_irq(i, pcibios_test_irq_handler, SA_SHIRQ, "pci-test", dev)) {
				free_irq(i, dev);
				newirq = i;
			}
		}
	}
	DBG(" -> newirq=%d", newirq);

	/* Check if it is hardcoded */
	if ((pirq & 0xf0) == 0xf0) {
		irq = pirq & 0xf;
		DBG(" -> hardcoded IRQ %d\n", irq);
		msg = "Hardcoded";
		if (dev->irq && dev->irq != irq) {
			printk("IRQ routing conflict in pirq table! Try 'pci=autoirq'\n");
			return 0;
		}
	} else if (r->get && (irq = r->get(pirq_router_dev, dev, pirq))) {
		DBG(" -> got IRQ %d\n", irq);
		msg = "Found";
		/* We refuse to override the dev->irq information. Give a warning! */
	    	if (dev->irq && dev->irq != irq) {
	    		printk("IRQ routing conflict in pirq table! Try 'pci=autoirq'\n");
	    		return 0;
	    	}
	} else if (newirq && r->set && (dev->class >> 8) != PCI_CLASS_DISPLAY_VGA) {
		DBG(" -> assigning IRQ %d", newirq);
		if (r->set(pirq_router_dev, dev, pirq, newirq)) {
			eisa_set_level_irq(newirq);
			DBG(" ... OK\n");
			msg = "Assigned";
			irq = newirq;
		}
	}

	if (!irq) {
		DBG(" ... failed\n");
		if (newirq && mask == (1 << newirq)) {
			msg = "Guessed";
			irq = newirq;
		} else
			return 0;
	}
	printk("PCI: %s IRQ %d for device %s\n", msg, irq, dev->slot_name);

	/* Update IRQ for all devices with the same pirq value */
	pci_for_each_dev(dev2) {
		pci_read_config_byte(dev2, PCI_INTERRUPT_PIN, &pin);
		if (!pin)
			continue;
		pin--;
		info = pirq_get_info(dev2);
		if (!info)
			continue;
		if (info->irq[pin].link == pirq) {
			dev2->irq = irq;
			pirq_penalty[irq]++;
			if (dev != dev2)
				printk("PCI: The same IRQ used for device %s\n", dev2->slot_name);
		}
	}
	return 1;
}

void __init pcibios_irq_init(void)
{
	DBG("PCI: IRQ init\n");
	pirq_table = pirq_find_routing_table();
#ifdef CONFIG_PCI_BIOS
	if (!pirq_table && (pci_probe & PCI_BIOS_IRQ_SCAN))
		pirq_table = pcibios_get_irq_routing_table();
#endif
	if (pirq_table) {
		pirq_peer_trick();
		pirq_find_router();
		if (pirq_table->exclusive_irqs) {
			int i;
			for (i=0; i<16; i++)
				if (!(pirq_table->exclusive_irqs & (1 << i)))
					pirq_penalty[i] += 100;
		}
		/* If we're using the I/O APIC, avoid using the PCI IRQ routing table */
		if (io_apic_assign_pci_irqs)
			pirq_table = NULL;
	}
}

void __init pcibios_fixup_irqs(void)
{
	struct pci_dev *dev;
	u8 pin;

	DBG("PCI: IRQ fixup\n");
	pci_for_each_dev(dev) {
		/*
		 * If the BIOS has set an out of range IRQ number, just ignore it.
		 * Also keep track of which IRQ's are already in use.
		 */
		if (dev->irq >= 16) {
			DBG("%s: ignoring bogus IRQ %d\n", dev->slot_name, dev->irq);
			dev->irq = 0;
		}
		/* If the IRQ is already assigned to a PCI device, ignore its ISA use penalty */
		if (pirq_penalty[dev->irq] >= 100 && pirq_penalty[dev->irq] < 100000)
			pirq_penalty[dev->irq] = 0;
		pirq_penalty[dev->irq]++;
	}

	pci_for_each_dev(dev) {
		pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
#ifdef CONFIG_X86_IO_APIC
		/*
		 * Recalculate IRQ numbers if we use the I/O APIC.
		 */
		if (io_apic_assign_pci_irqs)
		{
			int irq;

			if (pin) {
				pin--;		/* interrupt pins are numbered starting from 1 */
				irq = IO_APIC_get_PCI_irq_vector(dev->bus->number, PCI_SLOT(dev->devfn), pin);
/*
 * Will be removed completely if things work out well with fuzzy parsing
 */
#if 0
				if (irq < 0 && dev->bus->parent) { /* go back to the bridge */
					struct pci_dev * bridge = dev->bus->self;

					pin = (pin + PCI_SLOT(dev->devfn)) % 4;
					irq = IO_APIC_get_PCI_irq_vector(bridge->bus->number, 
							PCI_SLOT(bridge->devfn), pin);
					if (irq >= 0)
						printk(KERN_WARNING "PCI: using PPB(B%d,I%d,P%d) to get irq %d\n", 
							bridge->bus->number, PCI_SLOT(bridge->devfn), pin, irq);
				}
#endif
				if (irq >= 0) {
					printk("PCI->APIC IRQ transform: (B%d,I%d,P%d) -> %d\n",
						dev->bus->number, PCI_SLOT(dev->devfn), pin, irq);
					dev->irq = irq;
				}
			}
		}
#endif
		/*
		 * Still no IRQ? Try to lookup one...
		 */
		if (pin && !dev->irq)
			pcibios_lookup_irq(dev, 0);
	}
}

void pcibios_penalize_isa_irq(int irq)
{
	/*
	 *  If any ISAPnP device reports an IRQ in its list of possible
	 *  IRQ's, we try to avoid assigning it to PCI devices.
	 */
	pirq_penalty[irq] += 100;
}

void pcibios_enable_irq(struct pci_dev *dev)
{
	u8 pin;
	pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
	if (pin && !pcibios_lookup_irq(dev, 1) && !dev->irq) {
		char *msg;
		if (io_apic_assign_pci_irqs)
			msg = " Probably buggy MP table.";
		else if (pci_probe & PCI_BIOS_IRQ_SCAN)
			msg = "";
		else
			msg = " Please try using pci=biosirq.";
		printk(KERN_WARNING "PCI: No IRQ known for interrupt pin %c of device %s.%s\n",
		       'A' + pin - 1, dev->slot_name, msg);
	}
}