drivers/acpi/pci_irq.c - kernel/msm-4.19 - Gitiles

 /*
  *  pci_irq.c - ACPI PCI Interrupt Routing ($Revision: 11 $)
  *
  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
  *  Copyright (C) 2002       Dominik Brodowski <devel@brodo.de>
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 of the License, or (at
  *  your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful, but
  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  *  General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License along
  *  with this program; if not, write to the Free Software Foundation, Inc.,
  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  */

 #include <linux/config.h>

 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/proc_fs.h>
 #include <linux/spinlock.h>
 #include <linux/pm.h>
 #include <linux/pci.h>
 #include <linux/acpi.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>

 #define _COMPONENT		ACPI_PCI_COMPONENT
 ACPI_MODULE_NAME("pci_irq")

 static struct acpi_prt_list acpi_prt;
 static DEFINE_SPINLOCK(acpi_prt_lock);

 /* --------------------------------------------------------------------------
                          PCI IRQ Routing Table (PRT) Support
    -------------------------------------------------------------------------- */

 static struct acpi_prt_entry *acpi_pci_irq_find_prt_entry(int segment,
 							  int bus,
 							  int device, int pin)
 {
 	struct list_head *node = NULL;
 	struct acpi_prt_entry *entry = NULL;


 	if (!acpi_prt.count)
 		return NULL;

 	/*
 	 * Parse through all PRT entries looking for a match on the specified
 	 * PCI device's segment, bus, device, and pin (don't care about func).
 	 *
 	 */
 	spin_lock(&acpi_prt_lock);
 	list_for_each(node, &acpi_prt.entries) {
 		entry = list_entry(node, struct acpi_prt_entry, node);
 		if ((segment == entry->id.segment)
 		    && (bus == entry->id.bus)
 		    && (device == entry->id.device)
 		    && (pin == entry->pin)) {
 			spin_unlock(&acpi_prt_lock);
 			return entry;
 		}
 	}

 	spin_unlock(&acpi_prt_lock);
 	return NULL;
 }

 static int
 acpi_pci_irq_add_entry(acpi_handle handle,
 		       int segment, int bus, struct acpi_pci_routing_table *prt)
 {
 	struct acpi_prt_entry *entry = NULL;


 	if (!prt)
 		return -EINVAL;

 	entry = kmalloc(sizeof(struct acpi_prt_entry), GFP_KERNEL);
 	if (!entry)
 		return -ENOMEM;
 	memset(entry, 0, sizeof(struct acpi_prt_entry));

 	entry->id.segment = segment;
 	entry->id.bus = bus;
 	entry->id.device = (prt->address >> 16) & 0xFFFF;
 	entry->id.function = prt->address & 0xFFFF;
 	entry->pin = prt->pin;

 	/*
 	 * Type 1: Dynamic
 	 * ---------------
 	 * The 'source' field specifies the PCI interrupt link device used to
 	 * configure the IRQ assigned to this slot|dev|pin.  The 'source_index'
 	 * indicates which resource descriptor in the resource template (of
 	 * the link device) this interrupt is allocated from.
 	 *
 	 * NOTE: Don't query the Link Device for IRQ information at this time
 	 *       because Link Device enumeration may not have occurred yet
 	 *       (e.g. exists somewhere 'below' this _PRT entry in the ACPI
 	 *       namespace).
 	 */
 	if (prt->source[0]) {
 		acpi_get_handle(handle, prt->source, &entry->link.handle);
 		entry->link.index = prt->source_index;
 	}
 	/*
 	 * Type 2: Static
 	 * --------------
 	 * The 'source' field is NULL, and the 'source_index' field specifies
 	 * the IRQ value, which is hardwired to specific interrupt inputs on
 	 * the interrupt controller.
 	 */
 	else
 		entry->link.index = prt->source_index;

 	ACPI_DEBUG_PRINT_RAW((ACPI_DB_INFO,
 			      "      %02X:%02X:%02X[%c] -> %s[%d]\n",
 			      entry->id.segment, entry->id.bus,
 			      entry->id.device, ('A' + entry->pin), prt->source,
 			      entry->link.index));

 	spin_lock(&acpi_prt_lock);
 	list_add_tail(&entry->node, &acpi_prt.entries);
 	acpi_prt.count++;
 	spin_unlock(&acpi_prt_lock);

 	return 0;
 }

 static void
 acpi_pci_irq_del_entry(int segment, int bus, struct acpi_prt_entry *entry)
 {
 	if (segment == entry->id.segment && bus == entry->id.bus) {
 		acpi_prt.count--;
 		list_del(&entry->node);
 		kfree(entry);
 	}
 }

 int acpi_pci_irq_add_prt(acpi_handle handle, int segment, int bus)
 {
 	acpi_status status = AE_OK;
 	char *pathname = NULL;
 	struct acpi_buffer buffer = { 0, NULL };
 	struct acpi_pci_routing_table *prt = NULL;
 	struct acpi_pci_routing_table *entry = NULL;
 	static int first_time = 1;


 	pathname = (char *)kmalloc(ACPI_PATHNAME_MAX, GFP_KERNEL);
 	if (!pathname)
 		return -ENOMEM;
 	memset(pathname, 0, ACPI_PATHNAME_MAX);

 	if (first_time) {
 		acpi_prt.count = 0;
 		INIT_LIST_HEAD(&acpi_prt.entries);
 		first_time = 0;
 	}

 	/*
 	 * NOTE: We're given a 'handle' to the _PRT object's parent device
 	 *       (either a PCI root bridge or PCI-PCI bridge).
 	 */

 	buffer.length = ACPI_PATHNAME_MAX;
 	buffer.pointer = pathname;
 	acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);

 	printk(KERN_DEBUG "ACPI: PCI Interrupt Routing Table [%s._PRT]\n",
 	       pathname);

 	/*
 	 * Evaluate this _PRT and add its entries to our global list (acpi_prt).
 	 */

 	buffer.length = 0;
 	buffer.pointer = NULL;
 	kfree(pathname);
 	status = acpi_get_irq_routing_table(handle, &buffer);
 	if (status != AE_BUFFER_OVERFLOW) {
 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRT [%s]",
 				acpi_format_exception(status)));
 		return -ENODEV;
 	}

 	prt = kmalloc(buffer.length, GFP_KERNEL);
 	if (!prt) {
 		return -ENOMEM;
 	}
 	memset(prt, 0, buffer.length);
 	buffer.pointer = prt;

 	status = acpi_get_irq_routing_table(handle, &buffer);
 	if (ACPI_FAILURE(status)) {
 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRT [%s]",
 				acpi_format_exception(status)));
 		kfree(buffer.pointer);
 		return -ENODEV;
 	}

 	entry = prt;

 	while (entry && (entry->length > 0)) {
 		acpi_pci_irq_add_entry(handle, segment, bus, entry);
 		entry = (struct acpi_pci_routing_table *)
 		    ((unsigned long)entry + entry->length);
 	}

 	kfree(prt);

 	return 0;
 }

 void acpi_pci_irq_del_prt(int segment, int bus)
 {
 	struct list_head *node = NULL, *n = NULL;
 	struct acpi_prt_entry *entry = NULL;

 	if (!acpi_prt.count) {
 		return;
 	}

 	printk(KERN_DEBUG
 	       "ACPI: Delete PCI Interrupt Routing Table for %x:%x\n", segment,
 	       bus);
 	spin_lock(&acpi_prt_lock);
 	list_for_each_safe(node, n, &acpi_prt.entries) {
 		entry = list_entry(node, struct acpi_prt_entry, node);

 		acpi_pci_irq_del_entry(segment, bus, entry);
 	}
 	spin_unlock(&acpi_prt_lock);
 }

 /* --------------------------------------------------------------------------
                           PCI Interrupt Routing Support
    -------------------------------------------------------------------------- */
 typedef int (*irq_lookup_func) (struct acpi_prt_entry *, int *, int *, char **);

 static int
 acpi_pci_allocate_irq(struct acpi_prt_entry *entry,
 		      int *triggering, int *polarity, char **link)
 {
 	int irq;


 	if (entry->link.handle) {
 		irq = acpi_pci_link_allocate_irq(entry->link.handle,
 						 entry->link.index, triggering,
 						 polarity, link);
 		if (irq < 0) {
 			printk(KERN_WARNING PREFIX
 				      "Invalid IRQ link routing entry\n");
 			return -1;
 		}
 	} else {
 		irq = entry->link.index;
 		*triggering = ACPI_LEVEL_SENSITIVE;
 		*polarity = ACPI_ACTIVE_LOW;
 	}

 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found IRQ %d\n", irq));
 	return irq;
 }

 static int
 acpi_pci_free_irq(struct acpi_prt_entry *entry,
 		  int *triggering, int *polarity, char **link)
 {
 	int irq;

 	if (entry->link.handle) {
 		irq = acpi_pci_link_free_irq(entry->link.handle);
 	} else {
 		irq = entry->link.index;
 	}
 	return irq;
 }

 /*
  * acpi_pci_irq_lookup
  * success: return IRQ >= 0
  * failure: return -1
  */
 static int
 acpi_pci_irq_lookup(struct pci_bus *bus,
 		    int device,
 		    int pin,
 		    int *triggering,
 		    int *polarity, char **link, irq_lookup_func func)
 {
 	struct acpi_prt_entry *entry = NULL;
 	int segment = pci_domain_nr(bus);
 	int bus_nr = bus->number;
 	int ret;


 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 			  "Searching for PRT entry for %02x:%02x:%02x[%c]\n",
 			  segment, bus_nr, device, ('A' + pin)));

 	entry = acpi_pci_irq_find_prt_entry(segment, bus_nr, device, pin);
 	if (!entry) {
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "PRT entry not found\n"));
 		return -1;
 	}

 	ret = func(entry, triggering, polarity, link);
 	return ret;
 }

 /*
  * acpi_pci_irq_derive
  * success: return IRQ >= 0
  * failure: return < 0
  */
 static int
 acpi_pci_irq_derive(struct pci_dev *dev,
 		    int pin,
 		    int *triggering,
 		    int *polarity, char **link, irq_lookup_func func)
 {
 	struct pci_dev *bridge = dev;
 	int irq = -1;
 	u8 bridge_pin = 0;


 	if (!dev)
 		return -EINVAL;

 	/*
 	 * Attempt to derive an IRQ for this device from a parent bridge's
 	 * PCI interrupt routing entry (eg. yenta bridge and add-in card bridge).
 	 */
 	while (irq < 0 && bridge->bus->self) {
 		pin = (pin + PCI_SLOT(bridge->devfn)) % 4;
 		bridge = bridge->bus->self;

 		if ((bridge->class >> 8) == PCI_CLASS_BRIDGE_CARDBUS) {
 			/* PC card has the same IRQ as its cardbridge */
 			bridge_pin = bridge->pin;
 			if (!bridge_pin) {
 				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 						  "No interrupt pin configured for device %s\n",
 						  pci_name(bridge)));
 				return -1;
 			}
 			/* Pin is from 0 to 3 */
 			bridge_pin--;
 			pin = bridge_pin;
 		}

 		irq = acpi_pci_irq_lookup(bridge->bus, PCI_SLOT(bridge->devfn),
 					  pin, triggering, polarity,
 					  link, func);
 	}

 	if (irq < 0) {
 		printk(KERN_WARNING PREFIX "Unable to derive IRQ for device %s\n",
 			      pci_name(dev));
 		return -1;
 	}

 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Derive IRQ %d for device %s from %s\n",
 			  irq, pci_name(dev), pci_name(bridge)));

 	return irq;
 }

 /*
  * acpi_pci_irq_enable
  * success: return 0
  * failure: return < 0
  */

 int acpi_pci_irq_enable(struct pci_dev *dev)
 {
 	int irq = 0;
 	u8 pin = 0;
 	int triggering = ACPI_LEVEL_SENSITIVE;
 	int polarity = ACPI_ACTIVE_LOW;
 	char *link = NULL;
 	int rc;


 	if (!dev)
 		return -EINVAL;

 	pin = dev->pin;
 	if (!pin) {
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 				  "No interrupt pin configured for device %s\n",
 				  pci_name(dev)));
 		return 0;
 	}
 	pin--;

 	if (!dev->bus) {
 		printk(KERN_ERR PREFIX "Invalid (NULL) 'bus' field\n");
 		return -ENODEV;
 	}

 	/*
 	 * First we check the PCI IRQ routing table (PRT) for an IRQ.  PRT
 	 * values override any BIOS-assigned IRQs set during boot.
 	 */
 	irq = acpi_pci_irq_lookup(dev->bus, PCI_SLOT(dev->devfn), pin,
 				  &triggering, &polarity, &link,
 				  acpi_pci_allocate_irq);

 	/*
 	 * If no PRT entry was found, we'll try to derive an IRQ from the
 	 * device's parent bridge.
 	 */
 	if (irq < 0)
 		irq = acpi_pci_irq_derive(dev, pin, &triggering,
 					  &polarity, &link,
 					  acpi_pci_allocate_irq);

 	/*
 	 * No IRQ known to the ACPI subsystem - maybe the BIOS /
 	 * driver reported one, then use it. Exit in any case.
 	 */
 	if (irq < 0) {
 		printk(KERN_WARNING PREFIX "PCI Interrupt %s[%c]: no GSI",
 		       pci_name(dev), ('A' + pin));
 		/* Interrupt Line values above 0xF are forbidden */
 		if (dev->irq > 0 && (dev->irq <= 0xF)) {
 			printk(" - using IRQ %d\n", dev->irq);
 			acpi_register_gsi(dev->irq, ACPI_LEVEL_SENSITIVE,
 					  ACPI_ACTIVE_LOW);
 			return 0;
 		} else {
 			printk("\n");
 			return 0;
 		}
 	}

 	rc = acpi_register_gsi(irq, triggering, polarity);
 	if (rc < 0) {
 		printk(KERN_WARNING PREFIX "PCI Interrupt %s[%c]: failed "
 		       "to register GSI\n", pci_name(dev), ('A' + pin));
 		return rc;
 	}
 	dev->irq = rc;

 	printk(KERN_INFO PREFIX "PCI Interrupt %s[%c] -> ",
 	       pci_name(dev), 'A' + pin);

 	if (link)
 		printk("Link [%s] -> ", link);

 	printk("GSI %u (%s, %s) -> IRQ %d\n", irq,
 	       (triggering == ACPI_LEVEL_SENSITIVE) ? "level" : "edge",
 	       (polarity == ACPI_ACTIVE_LOW) ? "low" : "high", dev->irq);

 	return 0;
 }

 EXPORT_SYMBOL(acpi_pci_irq_enable);

 /* FIXME: implement x86/x86_64 version */
 void __attribute__ ((weak)) acpi_unregister_gsi(u32 i)
 {
 }

 void acpi_pci_irq_disable(struct pci_dev *dev)
 {
 	int gsi = 0;
 	u8 pin = 0;
 	int triggering = ACPI_LEVEL_SENSITIVE;
 	int polarity = ACPI_ACTIVE_LOW;


 	if (!dev || !dev->bus)
 		return;

 	pin = dev->pin;
 	if (!pin)
 		return;
 	pin--;

 	/*
 	 * First we check the PCI IRQ routing table (PRT) for an IRQ.
 	 */
 	gsi = acpi_pci_irq_lookup(dev->bus, PCI_SLOT(dev->devfn), pin,
 				  &triggering, &polarity, NULL,
 				  acpi_pci_free_irq);
 	/*
 	 * If no PRT entry was found, we'll try to derive an IRQ from the
 	 * device's parent bridge.
 	 */
 	if (gsi < 0)
 		gsi = acpi_pci_irq_derive(dev, pin,
 					  &triggering, &polarity, NULL,
 					  acpi_pci_free_irq);
 	if (gsi < 0)
 		return;

 	/*
 	 * TBD: It might be worth clearing dev->irq by magic constant
 	 * (e.g. PCI_UNDEFINED_IRQ).
 	 */

 	printk(KERN_INFO PREFIX "PCI interrupt for device %s disabled\n",
 	       pci_name(dev));

 	acpi_unregister_gsi(gsi);

 	return;
 }
	/*
	* pci_irq.c - ACPI PCI Interrupt Routing ($Revision: 11 $)
	*
	* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
	* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
	* Copyright (C) 2002 Dominik Brodowski <devel@brodo.de>
	*
	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or (at
	* your option) any later version.
	*
	* This program is distributed in the hope that it will be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License along
	* with this program; if not, write to the Free Software Foundation, Inc.,
	* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
	*
	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	*/

	#include <linux/config.h>

	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/types.h>
	#include <linux/proc_fs.h>
	#include <linux/spinlock.h>
	#include <linux/pm.h>
	#include <linux/pci.h>
	#include <linux/acpi.h>
	#include <acpi/acpi_bus.h>
	#include <acpi/acpi_drivers.h>

	#define _COMPONENT ACPI_PCI_COMPONENT
	ACPI_MODULE_NAME("pci_irq")

	static struct acpi_prt_list acpi_prt;
	static DEFINE_SPINLOCK(acpi_prt_lock);

	/* --------------------------------------------------------------------------
	PCI IRQ Routing Table (PRT) Support
	-------------------------------------------------------------------------- */

	static struct acpi_prt_entry *acpi_pci_irq_find_prt_entry(int segment,
	int bus,
	int device, int pin)
	{
	struct list_head *node = NULL;
	struct acpi_prt_entry *entry = NULL;


	if (!acpi_prt.count)
	return NULL;

	/*
	* Parse through all PRT entries looking for a match on the specified
	* PCI device's segment, bus, device, and pin (don't care about func).
	*
	*/
	spin_lock(&acpi_prt_lock);
	list_for_each(node, &acpi_prt.entries) {
	entry = list_entry(node, struct acpi_prt_entry, node);
	if ((segment == entry->id.segment)
	&& (bus == entry->id.bus)
	&& (device == entry->id.device)
	&& (pin == entry->pin)) {
	spin_unlock(&acpi_prt_lock);
	return entry;
	}
	}

	spin_unlock(&acpi_prt_lock);
	return NULL;
	}

	static int
	acpi_pci_irq_add_entry(acpi_handle handle,
	int segment, int bus, struct acpi_pci_routing_table *prt)
	{
	struct acpi_prt_entry *entry = NULL;


	if (!prt)
	return -EINVAL;

	entry = kmalloc(sizeof(struct acpi_prt_entry), GFP_KERNEL);
	if (!entry)
	return -ENOMEM;
	memset(entry, 0, sizeof(struct acpi_prt_entry));

	entry->id.segment = segment;
	entry->id.bus = bus;
	entry->id.device = (prt->address >> 16) & 0xFFFF;
	entry->id.function = prt->address & 0xFFFF;
	entry->pin = prt->pin;

	/*
	* Type 1: Dynamic
	* ---------------
	* The 'source' field specifies the PCI interrupt link device used to
	* configure the IRQ assigned to this slot\|dev\|pin. The 'source_index'
	* indicates which resource descriptor in the resource template (of
	* the link device) this interrupt is allocated from.
	*
	* NOTE: Don't query the Link Device for IRQ information at this time
	* because Link Device enumeration may not have occurred yet
	* (e.g. exists somewhere 'below' this _PRT entry in the ACPI
	* namespace).
	*/
	if (prt->source[0]) {
	acpi_get_handle(handle, prt->source, &entry->link.handle);
	entry->link.index = prt->source_index;
	}
	/*
	* Type 2: Static
	* --------------
	* The 'source' field is NULL, and the 'source_index' field specifies
	* the IRQ value, which is hardwired to specific interrupt inputs on
	* the interrupt controller.
	*/
	else
	entry->link.index = prt->source_index;

	ACPI_DEBUG_PRINT_RAW((ACPI_DB_INFO,
	" %02X:%02X:%02X[%c] -> %s[%d]\n",
	entry->id.segment, entry->id.bus,
	entry->id.device, ('A' + entry->pin), prt->source,
	entry->link.index));

	spin_lock(&acpi_prt_lock);
	list_add_tail(&entry->node, &acpi_prt.entries);
	acpi_prt.count++;
	spin_unlock(&acpi_prt_lock);

	return 0;
	}

	static void
	acpi_pci_irq_del_entry(int segment, int bus, struct acpi_prt_entry *entry)
	{
	if (segment == entry->id.segment && bus == entry->id.bus) {
	acpi_prt.count--;
	list_del(&entry->node);
	kfree(entry);
	}
	}

	int acpi_pci_irq_add_prt(acpi_handle handle, int segment, int bus)
	{
	acpi_status status = AE_OK;
	char *pathname = NULL;
	struct acpi_buffer buffer = { 0, NULL };
	struct acpi_pci_routing_table *prt = NULL;
	struct acpi_pci_routing_table *entry = NULL;
	static int first_time = 1;


	pathname = (char *)kmalloc(ACPI_PATHNAME_MAX, GFP_KERNEL);
	if (!pathname)
	return -ENOMEM;
	memset(pathname, 0, ACPI_PATHNAME_MAX);

	if (first_time) {
	acpi_prt.count = 0;
	INIT_LIST_HEAD(&acpi_prt.entries);
	first_time = 0;
	}

	/*
	* NOTE: We're given a 'handle' to the _PRT object's parent device
	* (either a PCI root bridge or PCI-PCI bridge).
	*/

	buffer.length = ACPI_PATHNAME_MAX;
	buffer.pointer = pathname;
	acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);

	printk(KERN_DEBUG "ACPI: PCI Interrupt Routing Table [%s._PRT]\n",
	pathname);

	/*
	* Evaluate this _PRT and add its entries to our global list (acpi_prt).
	*/

	buffer.length = 0;
	buffer.pointer = NULL;
	kfree(pathname);
	status = acpi_get_irq_routing_table(handle, &buffer);
	if (status != AE_BUFFER_OVERFLOW) {
	ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRT [%s]",
	acpi_format_exception(status)));
	return -ENODEV;
	}

	prt = kmalloc(buffer.length, GFP_KERNEL);
	if (!prt) {
	return -ENOMEM;
	}
	memset(prt, 0, buffer.length);
	buffer.pointer = prt;

	status = acpi_get_irq_routing_table(handle, &buffer);
	if (ACPI_FAILURE(status)) {
	ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRT [%s]",
	acpi_format_exception(status)));
	kfree(buffer.pointer);
	return -ENODEV;
	}

	entry = prt;

	while (entry && (entry->length > 0)) {
	acpi_pci_irq_add_entry(handle, segment, bus, entry);
	entry = (struct acpi_pci_routing_table *)
	((unsigned long)entry + entry->length);
	}

	kfree(prt);

	return 0;
	}

	void acpi_pci_irq_del_prt(int segment, int bus)
	{
	struct list_head node = NULL, n = NULL;
	struct acpi_prt_entry *entry = NULL;

	if (!acpi_prt.count) {
	return;
	}

	printk(KERN_DEBUG
	"ACPI: Delete PCI Interrupt Routing Table for %x:%x\n", segment,
	bus);
	spin_lock(&acpi_prt_lock);
	list_for_each_safe(node, n, &acpi_prt.entries) {
	entry = list_entry(node, struct acpi_prt_entry, node);

	acpi_pci_irq_del_entry(segment, bus, entry);
	}
	spin_unlock(&acpi_prt_lock);
	}

	/* --------------------------------------------------------------------------
	PCI Interrupt Routing Support
	-------------------------------------------------------------------------- */
	typedef int (irq_lookup_func) (struct acpi_prt_entry , int , int , char **);

	static int
	acpi_pci_allocate_irq(struct acpi_prt_entry *entry,
	int triggering, int polarity, char **link)
	{
	int irq;


	if (entry->link.handle) {
	irq = acpi_pci_link_allocate_irq(entry->link.handle,
	entry->link.index, triggering,
	polarity, link);
	if (irq < 0) {
	printk(KERN_WARNING PREFIX
	"Invalid IRQ link routing entry\n");
	return -1;
	}
	} else {
	irq = entry->link.index;
	*triggering = ACPI_LEVEL_SENSITIVE;
	*polarity = ACPI_ACTIVE_LOW;
	}

	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found IRQ %d\n", irq));
	return irq;
	}

	static int
	acpi_pci_free_irq(struct acpi_prt_entry *entry,
	int triggering, int polarity, char **link)
	{
	int irq;

	if (entry->link.handle) {
	irq = acpi_pci_link_free_irq(entry->link.handle);
	} else {
	irq = entry->link.index;
	}
	return irq;
	}

	/*
	* acpi_pci_irq_lookup
	* success: return IRQ >= 0
	* failure: return -1
	*/
	static int
	acpi_pci_irq_lookup(struct pci_bus *bus,
	int device,
	int pin,
	int *triggering,
	int polarity, char *link, irq_lookup_func func)
	{
	struct acpi_prt_entry *entry = NULL;
	int segment = pci_domain_nr(bus);
	int bus_nr = bus->number;
	int ret;


	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
	"Searching for PRT entry for %02x:%02x:%02x[%c]\n",
	segment, bus_nr, device, ('A' + pin)));

	entry = acpi_pci_irq_find_prt_entry(segment, bus_nr, device, pin);
	if (!entry) {
	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "PRT entry not found\n"));
	return -1;
	}

	ret = func(entry, triggering, polarity, link);
	return ret;
	}

	/*
	* acpi_pci_irq_derive
	* success: return IRQ >= 0
	* failure: return < 0
	*/
	static int
	acpi_pci_irq_derive(struct pci_dev *dev,
	int pin,
	int *triggering,
	int polarity, char *link, irq_lookup_func func)
	{
	struct pci_dev *bridge = dev;
	int irq = -1;
	u8 bridge_pin = 0;


	if (!dev)
	return -EINVAL;

	/*
	* Attempt to derive an IRQ for this device from a parent bridge's
	* PCI interrupt routing entry (eg. yenta bridge and add-in card bridge).
	*/
	while (irq < 0 && bridge->bus->self) {
	pin = (pin + PCI_SLOT(bridge->devfn)) % 4;
	bridge = bridge->bus->self;

	if ((bridge->class >> 8) == PCI_CLASS_BRIDGE_CARDBUS) {
	/* PC card has the same IRQ as its cardbridge */
	bridge_pin = bridge->pin;
	if (!bridge_pin) {
	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
	"No interrupt pin configured for device %s\n",
	pci_name(bridge)));
	return -1;
	}
	/* Pin is from 0 to 3 */
	bridge_pin--;
	pin = bridge_pin;
	}

	irq = acpi_pci_irq_lookup(bridge->bus, PCI_SLOT(bridge->devfn),
	pin, triggering, polarity,
	link, func);
	}

	if (irq < 0) {
	printk(KERN_WARNING PREFIX "Unable to derive IRQ for device %s\n",
	pci_name(dev));
	return -1;
	}

	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Derive IRQ %d for device %s from %s\n",
	irq, pci_name(dev), pci_name(bridge)));

	return irq;
	}

	/*
	* acpi_pci_irq_enable
	* success: return 0
	* failure: return < 0
	*/

	int acpi_pci_irq_enable(struct pci_dev *dev)
	{
	int irq = 0;
	u8 pin = 0;
	int triggering = ACPI_LEVEL_SENSITIVE;
	int polarity = ACPI_ACTIVE_LOW;
	char *link = NULL;
	int rc;


	if (!dev)
	return -EINVAL;

	pin = dev->pin;
	if (!pin) {
	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
	"No interrupt pin configured for device %s\n",
	pci_name(dev)));
	return 0;
	}
	pin--;

	if (!dev->bus) {
	printk(KERN_ERR PREFIX "Invalid (NULL) 'bus' field\n");
	return -ENODEV;
	}

	/*
	* First we check the PCI IRQ routing table (PRT) for an IRQ. PRT
	* values override any BIOS-assigned IRQs set during boot.
	*/
	irq = acpi_pci_irq_lookup(dev->bus, PCI_SLOT(dev->devfn), pin,
	&triggering, &polarity, &link,
	acpi_pci_allocate_irq);

	/*
	* If no PRT entry was found, we'll try to derive an IRQ from the
	* device's parent bridge.
	*/
	if (irq < 0)
	irq = acpi_pci_irq_derive(dev, pin, &triggering,
	&polarity, &link,
	acpi_pci_allocate_irq);

	/*
	* No IRQ known to the ACPI subsystem - maybe the BIOS /
	* driver reported one, then use it. Exit in any case.
	*/
	if (irq < 0) {
	printk(KERN_WARNING PREFIX "PCI Interrupt %s[%c]: no GSI",
	pci_name(dev), ('A' + pin));
	/* Interrupt Line values above 0xF are forbidden */
	if (dev->irq > 0 && (dev->irq <= 0xF)) {
	printk(" - using IRQ %d\n", dev->irq);
	acpi_register_gsi(dev->irq, ACPI_LEVEL_SENSITIVE,
	ACPI_ACTIVE_LOW);
	return 0;
	} else {
	printk("\n");
	return 0;
	}
	}

	rc = acpi_register_gsi(irq, triggering, polarity);
	if (rc < 0) {
	printk(KERN_WARNING PREFIX "PCI Interrupt %s[%c]: failed "
	"to register GSI\n", pci_name(dev), ('A' + pin));
	return rc;
	}
	dev->irq = rc;

	printk(KERN_INFO PREFIX "PCI Interrupt %s[%c] -> ",
	pci_name(dev), 'A' + pin);

	if (link)
	printk("Link [%s] -> ", link);

	printk("GSI %u (%s, %s) -> IRQ %d\n", irq,
	(triggering == ACPI_LEVEL_SENSITIVE) ? "level" : "edge",
	(polarity == ACPI_ACTIVE_LOW) ? "low" : "high", dev->irq);

	return 0;
	}

	EXPORT_SYMBOL(acpi_pci_irq_enable);

	/* FIXME: implement x86/x86_64 version */
	void __attribute__ ((weak)) acpi_unregister_gsi(u32 i)
	{
	}

	void acpi_pci_irq_disable(struct pci_dev *dev)
	{
	int gsi = 0;
	u8 pin = 0;
	int triggering = ACPI_LEVEL_SENSITIVE;
	int polarity = ACPI_ACTIVE_LOW;


	if (!dev \|\| !dev->bus)
	return;

	pin = dev->pin;
	if (!pin)
	return;
	pin--;

	/*
	* First we check the PCI IRQ routing table (PRT) for an IRQ.
	*/
	gsi = acpi_pci_irq_lookup(dev->bus, PCI_SLOT(dev->devfn), pin,
	&triggering, &polarity, NULL,
	acpi_pci_free_irq);
	/*
	* If no PRT entry was found, we'll try to derive an IRQ from the
	* device's parent bridge.
	*/
	if (gsi < 0)
	gsi = acpi_pci_irq_derive(dev, pin,
	&triggering, &polarity, NULL,
	acpi_pci_free_irq);
	if (gsi < 0)
	return;

	/*
	* TBD: It might be worth clearing dev->irq by magic constant
	* (e.g. PCI_UNDEFINED_IRQ).
	*/

	printk(KERN_INFO PREFIX "PCI interrupt for device %s disabled\n",
	pci_name(dev));

	acpi_unregister_gsi(gsi);

	return;
	}