drivers/acpi/pci_root.c - linux - Git at Google

 /*
  *  pci_root.c - ACPI PCI Root Bridge Driver ($Revision: 40 $)
  *
  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  *
  *  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/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_root");
 #define ACPI_PCI_ROOT_CLASS		"pci_bridge"
 #define ACPI_PCI_ROOT_HID		"PNP0A03"
 #define ACPI_PCI_ROOT_DRIVER_NAME	"ACPI PCI Root Bridge Driver"
 #define ACPI_PCI_ROOT_DEVICE_NAME	"PCI Root Bridge"
 static int acpi_pci_root_add(struct acpi_device *device);
 static int acpi_pci_root_remove(struct acpi_device *device, int type);
 static int acpi_pci_root_start(struct acpi_device *device);

 static struct acpi_driver acpi_pci_root_driver = {
 	.name = "pci_root",
 	.class = ACPI_PCI_ROOT_CLASS,
 	.ids = ACPI_PCI_ROOT_HID,
 	.ops = {
 		.add = acpi_pci_root_add,
 		.remove = acpi_pci_root_remove,
 		.start = acpi_pci_root_start,
 		},
 };

 struct acpi_pci_root {
 	struct list_head node;
 	struct acpi_device * device;
 	struct acpi_pci_id id;
 	struct pci_bus *bus;
 };

 static LIST_HEAD(acpi_pci_roots);

 static struct acpi_pci_driver *sub_driver;

 int acpi_pci_register_driver(struct acpi_pci_driver *driver)
 {
 	int n = 0;
 	struct list_head *entry;

 	struct acpi_pci_driver **pptr = &sub_driver;
 	while (*pptr)
 		pptr = &(*pptr)->next;
 	*pptr = driver;

 	if (!driver->add)
 		return 0;

 	list_for_each(entry, &acpi_pci_roots) {
 		struct acpi_pci_root *root;
 		root = list_entry(entry, struct acpi_pci_root, node);
 		driver->add(root->device->handle);
 		n++;
 	}

 	return n;
 }

 EXPORT_SYMBOL(acpi_pci_register_driver);

 void acpi_pci_unregister_driver(struct acpi_pci_driver *driver)
 {
 	struct list_head *entry;

 	struct acpi_pci_driver **pptr = &sub_driver;
 	while (*pptr) {
 		if (*pptr == driver)
 			break;
 		pptr = &(*pptr)->next;
 	}
 	BUG_ON(!*pptr);
 	*pptr = (*pptr)->next;

 	if (!driver->remove)
 		return;

 	list_for_each(entry, &acpi_pci_roots) {
 		struct acpi_pci_root *root;
 		root = list_entry(entry, struct acpi_pci_root, node);
 		driver->remove(root->device->handle);
 	}
 }

 EXPORT_SYMBOL(acpi_pci_unregister_driver);

 acpi_handle acpi_get_pci_rootbridge_handle(unsigned int seg, unsigned int bus)
 {
 	struct acpi_pci_root *tmp;

 	list_for_each_entry(tmp, &acpi_pci_roots, node) {
 		if ((tmp->id.segment == (u16) seg) && (tmp->id.bus == (u16) bus))
 			return tmp->device->handle;
 	}
 	return NULL;
 }

 EXPORT_SYMBOL_GPL(acpi_get_pci_rootbridge_handle);

 static acpi_status
 get_root_bridge_busnr_callback(struct acpi_resource *resource, void *data)
 {
 	int *busnr = data;
 	struct acpi_resource_address64 address;

 	if (resource->type != ACPI_RESOURCE_TYPE_ADDRESS16 &&
 	    resource->type != ACPI_RESOURCE_TYPE_ADDRESS32 &&
 	    resource->type != ACPI_RESOURCE_TYPE_ADDRESS64)
 		return AE_OK;

 	acpi_resource_to_address64(resource, &address);
 	if ((address.address_length > 0) &&
 	    (address.resource_type == ACPI_BUS_NUMBER_RANGE))
 		*busnr = address.minimum;

 	return AE_OK;
 }

 static acpi_status try_get_root_bridge_busnr(acpi_handle handle, int *busnum)
 {
 	acpi_status status;

 	*busnum = -1;
 	status =
 	    acpi_walk_resources(handle, METHOD_NAME__CRS,
 				get_root_bridge_busnr_callback, busnum);
 	if (ACPI_FAILURE(status))
 		return status;
 	/* Check if we really get a bus number from _CRS */
 	if (*busnum == -1)
 		return AE_ERROR;
 	return AE_OK;
 }

 static void acpi_pci_bridge_scan(struct acpi_device *device)
 {
 	int status;
 	struct acpi_device *child = NULL;

 	if (device->flags.bus_address)
 		if (device->parent && device->parent->ops.bind) {
 			status = device->parent->ops.bind(device);
 			if (!status) {
 				list_for_each_entry(child, &device->children, node)
 					acpi_pci_bridge_scan(child);
 			}
 		}
 }

 static int acpi_pci_root_add(struct acpi_device *device)
 {
 	int result = 0;
 	struct acpi_pci_root *root = NULL;
 	struct acpi_pci_root *tmp;
 	acpi_status status = AE_OK;
 	unsigned long value = 0;
 	acpi_handle handle = NULL;
 	struct acpi_device *child;


 	if (!device)
 		return -EINVAL;

 	root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
 	if (!root)
 		return -ENOMEM;
 	INIT_LIST_HEAD(&root->node);

 	root->device = device;
 	strcpy(acpi_device_name(device), ACPI_PCI_ROOT_DEVICE_NAME);
 	strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
 	acpi_driver_data(device) = root;

 	device->ops.bind = acpi_pci_bind;

 	/*
 	 * Segment
 	 * -------
 	 * Obtained via _SEG, if exists, otherwise assumed to be zero (0).
 	 */
 	status = acpi_evaluate_integer(device->handle, METHOD_NAME__SEG, NULL,
 				       &value);
 	switch (status) {
 	case AE_OK:
 		root->id.segment = (u16) value;
 		break;
 	case AE_NOT_FOUND:
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 				  "Assuming segment 0 (no _SEG)\n"));
 		root->id.segment = 0;
 		break;
 	default:
 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SEG"));
 		result = -ENODEV;
 		goto end;
 	}

 	/*
 	 * Bus
 	 * ---
 	 * Obtained via _BBN, if exists, otherwise assumed to be zero (0).
 	 */
 	status = acpi_evaluate_integer(device->handle, METHOD_NAME__BBN, NULL,
 				       &value);
 	switch (status) {
 	case AE_OK:
 		root->id.bus = (u16) value;
 		break;
 	case AE_NOT_FOUND:
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Assuming bus 0 (no _BBN)\n"));
 		root->id.bus = 0;
 		break;
 	default:
 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _BBN"));
 		result = -ENODEV;
 		goto end;
 	}

 	/* Some systems have wrong _BBN */
 	list_for_each_entry(tmp, &acpi_pci_roots, node) {
 		if ((tmp->id.segment == root->id.segment)
 		    && (tmp->id.bus == root->id.bus)) {
 			int bus = 0;
 			acpi_status status;

 			printk(KERN_ERR PREFIX
 				    "Wrong _BBN value, reboot"
 				    " and use option 'pci=noacpi'\n");

 			status = try_get_root_bridge_busnr(device->handle, &bus);
 			if (ACPI_FAILURE(status))
 				break;
 			if (bus != root->id.bus) {
 				printk(KERN_INFO PREFIX
 				       "PCI _CRS %d overrides _BBN 0\n", bus);
 				root->id.bus = bus;
 			}
 			break;
 		}
 	}
 	/*
 	 * Device & Function
 	 * -----------------
 	 * Obtained from _ADR (which has already been evaluated for us).
 	 */
 	root->id.device = device->pnp.bus_address >> 16;
 	root->id.function = device->pnp.bus_address & 0xFFFF;

 	/*
 	 * TBD: Need PCI interface for enumeration/configuration of roots.
 	 */

 	/* TBD: Locking */
 	list_add_tail(&root->node, &acpi_pci_roots);

 	printk(KERN_INFO PREFIX "%s [%s] (%04x:%02x)\n",
 	       acpi_device_name(device), acpi_device_bid(device),
 	       root->id.segment, root->id.bus);

 	/*
 	 * Scan the Root Bridge
 	 * --------------------
 	 * Must do this prior to any attempt to bind the root device, as the
 	 * PCI namespace does not get created until this call is made (and
 	 * thus the root bridge's pci_dev does not exist).
 	 */
 	root->bus = pci_acpi_scan_root(device, root->id.segment, root->id.bus);
 	if (!root->bus) {
 		printk(KERN_ERR PREFIX
 			    "Bus %04x:%02x not present in PCI namespace\n",
 			    root->id.segment, root->id.bus);
 		result = -ENODEV;
 		goto end;
 	}

 	/*
 	 * Attach ACPI-PCI Context
 	 * -----------------------
 	 * Thus binding the ACPI and PCI devices.
 	 */
 	result = acpi_pci_bind_root(device, &root->id, root->bus);
 	if (result)
 		goto end;

 	/*
 	 * PCI Routing Table
 	 * -----------------
 	 * Evaluate and parse _PRT, if exists.
 	 */
 	status = acpi_get_handle(device->handle, METHOD_NAME__PRT, &handle);
 	if (ACPI_SUCCESS(status))
 		result = acpi_pci_irq_add_prt(device->handle, root->id.segment,
 					      root->id.bus);

 	/*
 	 * Scan and bind all _ADR-Based Devices
 	 */
 	list_for_each_entry(child, &device->children, node)
 		acpi_pci_bridge_scan(child);

       end:
 	if (result) {
 		if (!list_empty(&root->node))
 			list_del(&root->node);
 		kfree(root);
 	}

 	return result;
 }

 static int acpi_pci_root_start(struct acpi_device *device)
 {
 	struct acpi_pci_root *root;


 	list_for_each_entry(root, &acpi_pci_roots, node) {
 		if (root->device == device) {
 			pci_bus_add_devices(root->bus);
 			return 0;
 		}
 	}
 	return -ENODEV;
 }

 static int acpi_pci_root_remove(struct acpi_device *device, int type)
 {
 	struct acpi_pci_root *root = NULL;


 	if (!device || !acpi_driver_data(device))
 		return -EINVAL;

 	root = acpi_driver_data(device);

 	kfree(root);

 	return 0;
 }

 static int __init acpi_pci_root_init(void)
 {

 	if (acpi_pci_disabled)
 		return 0;

 	/* DEBUG:
 	   acpi_dbg_layer = ACPI_PCI_COMPONENT;
 	   acpi_dbg_level = 0xFFFFFFFF;
 	 */

 	if (acpi_bus_register_driver(&acpi_pci_root_driver) < 0)
 		return -ENODEV;

 	return 0;
 }

 subsys_initcall(acpi_pci_root_init);
	/*
	* pci_root.c - ACPI PCI Root Bridge Driver ($Revision: 40 $)
	*
	* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
	* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
	*
	* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
	*
	* 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/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_root");
	#define ACPI_PCI_ROOT_CLASS "pci_bridge"
	#define ACPI_PCI_ROOT_HID "PNP0A03"
	#define ACPI_PCI_ROOT_DRIVER_NAME "ACPI PCI Root Bridge Driver"
	#define ACPI_PCI_ROOT_DEVICE_NAME "PCI Root Bridge"
	static int acpi_pci_root_add(struct acpi_device *device);
	static int acpi_pci_root_remove(struct acpi_device *device, int type);
	static int acpi_pci_root_start(struct acpi_device *device);

	static struct acpi_driver acpi_pci_root_driver = {
	.name = "pci_root",
	.class = ACPI_PCI_ROOT_CLASS,
	.ids = ACPI_PCI_ROOT_HID,
	.ops = {
	.add = acpi_pci_root_add,
	.remove = acpi_pci_root_remove,
	.start = acpi_pci_root_start,
	},
	};

	struct acpi_pci_root {
	struct list_head node;
	struct acpi_device * device;
	struct acpi_pci_id id;
	struct pci_bus *bus;
	};

	static LIST_HEAD(acpi_pci_roots);

	static struct acpi_pci_driver *sub_driver;

	int acpi_pci_register_driver(struct acpi_pci_driver *driver)
	{
	int n = 0;
	struct list_head *entry;

	struct acpi_pci_driver **pptr = &sub_driver;
	while (*pptr)
	pptr = &(*pptr)->next;
	*pptr = driver;

	if (!driver->add)
	return 0;

	list_for_each(entry, &acpi_pci_roots) {
	struct acpi_pci_root *root;
	root = list_entry(entry, struct acpi_pci_root, node);
	driver->add(root->device->handle);
	n++;
	}

	return n;
	}

	EXPORT_SYMBOL(acpi_pci_register_driver);

	void acpi_pci_unregister_driver(struct acpi_pci_driver *driver)
	{
	struct list_head *entry;

	struct acpi_pci_driver **pptr = &sub_driver;
	while (*pptr) {
	if (*pptr == driver)
	break;
	pptr = &(*pptr)->next;
	}
	BUG_ON(!*pptr);
	pptr = (pptr)->next;

	if (!driver->remove)
	return;

	list_for_each(entry, &acpi_pci_roots) {
	struct acpi_pci_root *root;
	root = list_entry(entry, struct acpi_pci_root, node);
	driver->remove(root->device->handle);
	}
	}

	EXPORT_SYMBOL(acpi_pci_unregister_driver);

	acpi_handle acpi_get_pci_rootbridge_handle(unsigned int seg, unsigned int bus)
	{
	struct acpi_pci_root *tmp;

	list_for_each_entry(tmp, &acpi_pci_roots, node) {
	if ((tmp->id.segment == (u16) seg) && (tmp->id.bus == (u16) bus))
	return tmp->device->handle;
	}
	return NULL;
	}

	EXPORT_SYMBOL_GPL(acpi_get_pci_rootbridge_handle);

	static acpi_status
	get_root_bridge_busnr_callback(struct acpi_resource resource, void data)
	{
	int *busnr = data;
	struct acpi_resource_address64 address;

	if (resource->type != ACPI_RESOURCE_TYPE_ADDRESS16 &&
	resource->type != ACPI_RESOURCE_TYPE_ADDRESS32 &&
	resource->type != ACPI_RESOURCE_TYPE_ADDRESS64)
	return AE_OK;

	acpi_resource_to_address64(resource, &address);
	if ((address.address_length > 0) &&
	(address.resource_type == ACPI_BUS_NUMBER_RANGE))
	*busnr = address.minimum;

	return AE_OK;
	}

	static acpi_status try_get_root_bridge_busnr(acpi_handle handle, int *busnum)
	{
	acpi_status status;

	*busnum = -1;
	status =
	acpi_walk_resources(handle, METHOD_NAME__CRS,
	get_root_bridge_busnr_callback, busnum);
	if (ACPI_FAILURE(status))
	return status;
	/* Check if we really get a bus number from _CRS */
	if (*busnum == -1)
	return AE_ERROR;
	return AE_OK;
	}

	static void acpi_pci_bridge_scan(struct acpi_device *device)
	{
	int status;
	struct acpi_device *child = NULL;

	if (device->flags.bus_address)
	if (device->parent && device->parent->ops.bind) {
	status = device->parent->ops.bind(device);
	if (!status) {
	list_for_each_entry(child, &device->children, node)
	acpi_pci_bridge_scan(child);
	}
	}
	}

	static int acpi_pci_root_add(struct acpi_device *device)
	{
	int result = 0;
	struct acpi_pci_root *root = NULL;
	struct acpi_pci_root *tmp;
	acpi_status status = AE_OK;
	unsigned long value = 0;
	acpi_handle handle = NULL;
	struct acpi_device *child;


	if (!device)
	return -EINVAL;

	root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
	if (!root)
	return -ENOMEM;
	INIT_LIST_HEAD(&root->node);

	root->device = device;
	strcpy(acpi_device_name(device), ACPI_PCI_ROOT_DEVICE_NAME);
	strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
	acpi_driver_data(device) = root;

	device->ops.bind = acpi_pci_bind;

	/*
	* Segment
	* -------
	* Obtained via _SEG, if exists, otherwise assumed to be zero (0).
	*/
	status = acpi_evaluate_integer(device->handle, METHOD_NAME__SEG, NULL,
	&value);
	switch (status) {
	case AE_OK:
	root->id.segment = (u16) value;
	break;
	case AE_NOT_FOUND:
	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
	"Assuming segment 0 (no _SEG)\n"));
	root->id.segment = 0;
	break;
	default:
	ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SEG"));
	result = -ENODEV;
	goto end;
	}

	/*
	* Bus
	* ---
	* Obtained via _BBN, if exists, otherwise assumed to be zero (0).
	*/
	status = acpi_evaluate_integer(device->handle, METHOD_NAME__BBN, NULL,
	&value);
	switch (status) {
	case AE_OK:
	root->id.bus = (u16) value;
	break;
	case AE_NOT_FOUND:
	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Assuming bus 0 (no _BBN)\n"));
	root->id.bus = 0;
	break;
	default:
	ACPI_EXCEPTION((AE_INFO, status, "Evaluating _BBN"));
	result = -ENODEV;
	goto end;
	}

	/* Some systems have wrong _BBN */
	list_for_each_entry(tmp, &acpi_pci_roots, node) {
	if ((tmp->id.segment == root->id.segment)
	&& (tmp->id.bus == root->id.bus)) {
	int bus = 0;
	acpi_status status;

	printk(KERN_ERR PREFIX
	"Wrong _BBN value, reboot"
	" and use option 'pci=noacpi'\n");

	status = try_get_root_bridge_busnr(device->handle, &bus);
	if (ACPI_FAILURE(status))
	break;
	if (bus != root->id.bus) {
	printk(KERN_INFO PREFIX
	"PCI _CRS %d overrides _BBN 0\n", bus);
	root->id.bus = bus;
	}
	break;
	}
	}
	/*
	* Device & Function
	* -----------------
	* Obtained from _ADR (which has already been evaluated for us).
	*/
	root->id.device = device->pnp.bus_address >> 16;
	root->id.function = device->pnp.bus_address & 0xFFFF;

	/*
	* TBD: Need PCI interface for enumeration/configuration of roots.
	*/

	/* TBD: Locking */
	list_add_tail(&root->node, &acpi_pci_roots);

	printk(KERN_INFO PREFIX "%s [%s] (%04x:%02x)\n",
	acpi_device_name(device), acpi_device_bid(device),
	root->id.segment, root->id.bus);

	/*
	* Scan the Root Bridge
	* --------------------
	* Must do this prior to any attempt to bind the root device, as the
	* PCI namespace does not get created until this call is made (and
	* thus the root bridge's pci_dev does not exist).
	*/
	root->bus = pci_acpi_scan_root(device, root->id.segment, root->id.bus);
	if (!root->bus) {
	printk(KERN_ERR PREFIX
	"Bus %04x:%02x not present in PCI namespace\n",
	root->id.segment, root->id.bus);
	result = -ENODEV;
	goto end;
	}

	/*
	* Attach ACPI-PCI Context
	* -----------------------
	* Thus binding the ACPI and PCI devices.
	*/
	result = acpi_pci_bind_root(device, &root->id, root->bus);
	if (result)
	goto end;

	/*
	* PCI Routing Table
	* -----------------
	* Evaluate and parse _PRT, if exists.
	*/
	status = acpi_get_handle(device->handle, METHOD_NAME__PRT, &handle);
	if (ACPI_SUCCESS(status))
	result = acpi_pci_irq_add_prt(device->handle, root->id.segment,
	root->id.bus);

	/*
	* Scan and bind all _ADR-Based Devices
	*/
	list_for_each_entry(child, &device->children, node)
	acpi_pci_bridge_scan(child);

	end:
	if (result) {
	if (!list_empty(&root->node))
	list_del(&root->node);
	kfree(root);
	}

	return result;
	}

	static int acpi_pci_root_start(struct acpi_device *device)
	{
	struct acpi_pci_root *root;


	list_for_each_entry(root, &acpi_pci_roots, node) {
	if (root->device == device) {
	pci_bus_add_devices(root->bus);
	return 0;
	}
	}
	return -ENODEV;
	}

	static int acpi_pci_root_remove(struct acpi_device *device, int type)
	{
	struct acpi_pci_root *root = NULL;


	if (!device \|\| !acpi_driver_data(device))
	return -EINVAL;

	root = acpi_driver_data(device);

	kfree(root);

	return 0;
	}

	static int __init acpi_pci_root_init(void)
	{

	if (acpi_pci_disabled)
	return 0;

	/* DEBUG:
	acpi_dbg_layer = ACPI_PCI_COMPONENT;
	acpi_dbg_level = 0xFFFFFFFF;
	*/

	if (acpi_bus_register_driver(&acpi_pci_root_driver) < 0)
	return -ENODEV;

	return 0;
	}

	subsys_initcall(acpi_pci_root_init);