Commit ac7cd5e1 authored by Maciej W. Rozycki's avatar Maciej W. Rozycki Committed by Thomas Gleixner
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x86/PCI: Handle PIRQ routing tables with no router device given 



PIRQ routing tables provided by the PCI BIOS usually specify the PCI 
vendor:device ID as well as the bus address of the device implementing 
the PIRQ router, e.g.:

PCI: Interrupt Routing Table found at 0xc00fde10
[...]
PCI: Attempting to find IRQ router for [8086:7000]
pci 0000:00:07.0: PIIX/ICH IRQ router [8086:7000]

however in some cases they do not, in which case we fail to match the 
router handler, e.g.:

PCI: Interrupt Routing Table found at 0xc00fdae0
[...]
PCI: Attempting to find IRQ router for [0000:0000]
PCI: Interrupt router not found at 00:00

This is because we always match the vendor:device ID and the bus address 
literally, even if they are all zeros.

Handle this case then and iterate over all PCI devices until we find a 
matching router handler if the vendor ID given by the routing table is 
the invalid value of zero:

PCI: Attempting to find IRQ router for [0000:0000]
PCI: Trying IRQ router for [1039:0496]
pci 0000:00:05.0: SiS85C497 IRQ router [1039:0496]

Signed-off-by: default avatarMaciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarNikolai Zhubr <zhubr.2@gmail.com>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2203302018570.9038@angie.orcam.me.uk
parent 5d64089a

arch/x86/pci/irq.c

+44 −20
Original line number Diff line number Diff line
@@ -1175,10 +1175,32 @@ static struct pci_dev *pirq_router_dev; 
 *	chipset" ?

 */



static bool __init pirq_try_router(struct irq_router *r,

				   struct irq_routing_table *rt,

				   struct pci_dev *dev)

{

	struct irq_router_handler *h;



	DBG(KERN_DEBUG "PCI: Trying IRQ router for [%04x:%04x]\n",

	    dev->vendor, dev->device);



	for (h = pirq_routers; h->vendor; h++) {

		/* First look for a router match */

		if (rt->rtr_vendor == h->vendor &&

		    h->probe(r, dev, rt->rtr_device))

			return true;

		/* Fall back to a device match */

		if (dev->vendor == h->vendor &&

		    h->probe(r, dev, dev->device))

			return true;

	}

	return false;

}



static void __init pirq_find_router(struct irq_router *r)

{

	struct irq_routing_table *rt = pirq_table;

	struct irq_router_handler *h;

	struct pci_dev *dev;



#ifdef CONFIG_PCI_BIOS

	if (!rt->signature) {
@@ -1197,27 +1219,29 @@ static void __init pirq_find_router(struct irq_router *r) 
	DBG(KERN_DEBUG "PCI: Attempting to find IRQ router for [%04x:%04x]\n",

	    rt->rtr_vendor, rt->rtr_device);



	pirq_router_dev = pci_get_domain_bus_and_slot(0, rt->rtr_bus,

	/* Use any vendor:device provided by the routing table or try all.  */

	if (rt->rtr_vendor) {

		dev = pci_get_domain_bus_and_slot(0, rt->rtr_bus,

						  rt->rtr_devfn);

	if (!pirq_router_dev) {

		DBG(KERN_DEBUG "PCI: Interrupt router not found at "

			"%02x:%02x\n", rt->rtr_bus, rt->rtr_devfn);

		return;

	}



	for (h = pirq_routers; h->vendor; h++) {

		/* First look for a router match */

		if (rt->rtr_vendor == h->vendor &&

			h->probe(r, pirq_router_dev, rt->rtr_device))

			break;

		/* Fall back to a device match */

		if (pirq_router_dev->vendor == h->vendor &&

			h->probe(r, pirq_router_dev, pirq_router_dev->device))

		if (dev && pirq_try_router(r, rt, dev))

			pirq_router_dev = dev;

	} else {

		dev = NULL;

		for_each_pci_dev(dev) {

			if (pirq_try_router(r, rt, dev)) {

				pirq_router_dev = dev;

				break;

			}

		}

	}



	if (pirq_router_dev)

		dev_info(&pirq_router_dev->dev, "%s IRQ router [%04x:%04x]\n",

			 pirq_router.name,

			 pirq_router_dev->vendor, pirq_router_dev->device);

	else

		DBG(KERN_DEBUG "PCI: Interrupt router not found at "

		    "%02x:%02x\n", rt->rtr_bus, rt->rtr_devfn);



	/* The device remains referenced for the kernel lifetime */

}