[linux.git] / drivers / pci / search.c

/*
 * 	PCI searching functions.
 *
 *	Copyright (C) 1993 -- 1997 Drew Eckhardt, Frederic Potter,
 *					David Mosberger-Tang
 *	Copyright (C) 1997 -- 2000 Martin Mares <[email protected]>
 *	Copyright (C) 2003 -- 2004 Greg Kroah-Hartman <[email protected]>
 */

#include <linux/init.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include "pci.h"

DECLARE_RWSEM(pci_bus_sem);
/*
 * find the upstream PCIe-to-PCI bridge of a PCI device
 * if the device is PCIE, return NULL
 * if the device isn't connected to a PCIe bridge (that is its parent is a
 * legacy PCI bridge and the bridge is directly connected to bus 0), return its
 * parent
 */
struct pci_dev *
pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
{
	struct pci_dev *tmp = NULL;

	if (pci_is_pcie(pdev))
		return NULL;
	while (1) {
		if (pci_is_root_bus(pdev->bus))
			break;
		pdev = pdev->bus->self;
		/* a p2p bridge */
		if (!pci_is_pcie(pdev)) {
			tmp = pdev;
			continue;
		}
		/* PCI device should connect to a PCIe bridge */
		if (pdev->pcie_type != PCI_EXP_TYPE_PCI_BRIDGE) {
			/* Busted hardware? */
			WARN_ON_ONCE(1);
			return NULL;
		}
		return pdev;
	}

	return tmp;
}

static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
{
	struct pci_bus* child;
	struct list_head *tmp;

	if(bus->number == busnr)
		return bus;

	list_for_each(tmp, &bus->children) {
		child = pci_do_find_bus(pci_bus_b(tmp), busnr);
		if(child)
			return child;
	}
	return NULL;
}

/**
 * pci_find_bus - locate PCI bus from a given domain and bus number
 * @domain: number of PCI domain to search
 * @busnr: number of desired PCI bus
 *
 * Given a PCI bus number and domain number, the desired PCI bus is located
 * in the global list of PCI buses.  If the bus is found, a pointer to its
 * data structure is returned.  If no bus is found, %NULL is returned.
 */
struct pci_bus * pci_find_bus(int domain, int busnr)
{
	struct pci_bus *bus = NULL;
	struct pci_bus *tmp_bus;

	while ((bus = pci_find_next_bus(bus)) != NULL)  {
		if (pci_domain_nr(bus) != domain)
			continue;
		tmp_bus = pci_do_find_bus(bus, busnr);
		if (tmp_bus)
			return tmp_bus;
	}
	return NULL;
}

/**
 * pci_find_next_bus - begin or continue searching for a PCI bus
 * @from: Previous PCI bus found, or %NULL for new search.
 *
 * Iterates through the list of known PCI busses.  A new search is
 * initiated by passing %NULL as the @from argument.  Otherwise if
 * @from is not %NULL, searches continue from next device on the
 * global list.
 */
struct pci_bus * 
pci_find_next_bus(const struct pci_bus *from)
{
	struct list_head *n;
	struct pci_bus *b = NULL;

	WARN_ON(in_interrupt());
	down_read(&pci_bus_sem);
	n = from ? from->node.next : pci_root_buses.next;
	if (n != &pci_root_buses)
		b = pci_bus_b(n);
	up_read(&pci_bus_sem);
	return b;
}

/**
 * pci_get_slot - locate PCI device for a given PCI slot
 * @bus: PCI bus on which desired PCI device resides
 * @devfn: encodes number of PCI slot in which the desired PCI 
 * device resides and the logical device number within that slot 
 * in case of multi-function devices.
 *
 * Given a PCI bus and slot/function number, the desired PCI device 
 * is located in the list of PCI devices.
 * If the device is found, its reference count is increased and this
 * function returns a pointer to its data structure.  The caller must
 * decrement the reference count by calling pci_dev_put().
 * If no device is found, %NULL is returned.
 */
struct pci_dev * pci_get_slot(struct pci_bus *bus, unsigned int devfn)
{
	struct list_head *tmp;
	struct pci_dev *dev;

	WARN_ON(in_interrupt());
	down_read(&pci_bus_sem);

	list_for_each(tmp, &bus->devices) {
		dev = pci_dev_b(tmp);
		if (dev->devfn == devfn)
			goto out;
	}

	dev = NULL;
 out:
	pci_dev_get(dev);
	up_read(&pci_bus_sem);
	return dev;
}

/**
 * pci_get_domain_bus_and_slot - locate PCI device for a given PCI domain (segment), bus, and slot
 * @domain: PCI domain/segment on which the PCI device resides.
 * @bus: PCI bus on which desired PCI device resides
 * @devfn: encodes number of PCI slot in which the desired PCI device
 * resides and the logical device number within that slot in case of
 * multi-function devices.
 *
 * Given a PCI domain, bus, and slot/function number, the desired PCI
 * device is located in the list of PCI devices. If the device is
 * found, its reference count is increased and this function returns a
 * pointer to its data structure.  The caller must decrement the
 * reference count by calling pci_dev_put().  If no device is found,
 * %NULL is returned.
 */
struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus,
					    unsigned int devfn)
{
	struct pci_dev *dev = NULL;

	for_each_pci_dev(dev) {
		if (pci_domain_nr(dev->bus) == domain &&
		    (dev->bus->number == bus && dev->devfn == devfn))
			return dev;
	}
	return NULL;
}
EXPORT_SYMBOL(pci_get_domain_bus_and_slot);

static int match_pci_dev_by_id(struct device *dev, void *data)
{
	struct pci_dev *pdev = to_pci_dev(dev);
	struct pci_device_id *id = data;

	if (pci_match_one_device(id, pdev))
		return 1;
	return 0;
}

/*
 * pci_get_dev_by_id - begin or continue searching for a PCI device by id
 * @id: pointer to struct pci_device_id to match for the device
 * @from: Previous PCI device found in search, or %NULL for new search.
 *
 * Iterates through the list of known PCI devices.  If a PCI device is found
 * with a matching id a pointer to its device structure is returned, and the
 * reference count to the device is incremented.  Otherwise, %NULL is returned.
 * A new search is initiated by passing %NULL as the @from argument.  Otherwise
 * if @from is not %NULL, searches continue from next device on the global
 * list.  The reference count for @from is always decremented if it is not
 * %NULL.
 *
 * This is an internal function for use by the other search functions in
 * this file.
 */
static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id,
					 struct pci_dev *from)
{
	struct device *dev;
	struct device *dev_start = NULL;
	struct pci_dev *pdev = NULL;

	WARN_ON(in_interrupt());
	if (from)
		dev_start = &from->dev;
	dev = bus_find_device(&pci_bus_type, dev_start, (void *)id,
			      match_pci_dev_by_id);
	if (dev)
		pdev = to_pci_dev(dev);
	if (from)
		pci_dev_put(from);
	return pdev;
}

/**
 * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
 * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
 * @from: Previous PCI device found in search, or %NULL for new search.
 *
 * Iterates through the list of known PCI devices.  If a PCI device is found
 * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its
 * device structure is returned, and the reference count to the device is
 * incremented.  Otherwise, %NULL is returned.  A new search is initiated by
 * passing %NULL as the @from argument.  Otherwise if @from is not %NULL,
 * searches continue from next device on the global list.
 * The reference count for @from is always decremented if it is not %NULL.
 */
struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
			       unsigned int ss_vendor, unsigned int ss_device,
			       struct pci_dev *from)
{
	struct pci_dev *pdev;
	struct pci_device_id *id;

	/*
	 * pci_find_subsys() can be called on the ide_setup() path,
	 * super-early in boot.  But the down_read() will enable local
	 * interrupts, which can cause some machines to crash.  So here we
	 * detect and flag that situation and bail out early.
	 */
	if (unlikely(no_pci_devices()))
		return NULL;

	id = kzalloc(sizeof(*id), GFP_KERNEL);
	if (!id)
		return NULL;
	id->vendor = vendor;
	id->device = device;
	id->subvendor = ss_vendor;
	id->subdevice = ss_device;

	pdev = pci_get_dev_by_id(id, from);
	kfree(id);

	return pdev;
}

/**
 * pci_get_device - begin or continue searching for a PCI device by vendor/device id
 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 * @from: Previous PCI device found in search, or %NULL for new search.
 *
 * Iterates through the list of known PCI devices.  If a PCI device is
 * found with a matching @vendor and @device, the reference count to the
 * device is incremented and a pointer to its device structure is returned.
 * Otherwise, %NULL is returned.  A new search is initiated by passing %NULL
 * as the @from argument.  Otherwise if @from is not %NULL, searches continue
 * from next device on the global list.  The reference count for @from is
 * always decremented if it is not %NULL.
 */
struct pci_dev *
pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from)
{
	return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
}

/**
 * pci_get_class - begin or continue searching for a PCI device by class
 * @class: search for a PCI device with this class designation
 * @from: Previous PCI device found in search, or %NULL for new search.
 *
 * Iterates through the list of known PCI devices.  If a PCI device is
 * found with a matching @class, the reference count to the device is
 * incremented and a pointer to its device structure is returned.
 * Otherwise, %NULL is returned.
 * A new search is initiated by passing %NULL as the @from argument.
 * Otherwise if @from is not %NULL, searches continue from next device
 * on the global list.  The reference count for @from is always decremented
 * if it is not %NULL.
 */
struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
{
	struct pci_dev *dev;
	struct pci_device_id *id;

	id = kzalloc(sizeof(*id), GFP_KERNEL);
	if (!id)
		return NULL;
	id->vendor = id->device = id->subvendor = id->subdevice = PCI_ANY_ID;
	id->class_mask = PCI_ANY_ID;
	id->class = class;

	dev = pci_get_dev_by_id(id, from);
	kfree(id);
	return dev;
}

/**
 * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
 * @ids: A pointer to a null terminated list of struct pci_device_id structures
 * that describe the type of PCI device the caller is trying to find.
 *
 * Obvious fact: You do not have a reference to any device that might be found
 * by this function, so if that device is removed from the system right after
 * this function is finished, the value will be stale.  Use this function to
 * find devices that are usually built into a system, or for a general hint as
 * to if another device happens to be present at this specific moment in time.
 */
int pci_dev_present(const struct pci_device_id *ids)
{
	struct pci_dev *found = NULL;

	WARN_ON(in_interrupt());
	while (ids->vendor || ids->subvendor || ids->class_mask) {
		found = pci_get_dev_by_id(ids, NULL);
		if (found)
			goto exit;
		ids++;
	}
exit:
	if (found)
		return 1;
	return 0;
}
EXPORT_SYMBOL(pci_dev_present);

/* For boot time work */
EXPORT_SYMBOL(pci_find_bus);
EXPORT_SYMBOL(pci_find_next_bus);
/* For everyone */
EXPORT_SYMBOL(pci_get_device);
EXPORT_SYMBOL(pci_get_subsys);
EXPORT_SYMBOL(pci_get_slot);
EXPORT_SYMBOL(pci_get_class);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* PCI searching functions.
	3	*
	4	* Copyright (C) 1993 -- 1997 Drew Eckhardt, Frederic Potter,
	5	* David Mosberger-Tang
	6	* Copyright (C) 1997 -- 2000 Martin Mares <[email protected]>
	7	* Copyright (C) 2003 -- 2004 Greg Kroah-Hartman <[email protected]>
	8	*/
	9
	10	#include <linux/init.h>
	11	#include <linux/pci.h>
5a0e3ad6	12	#include <linux/slab.h>
1da177e4 LT	13	#include <linux/module.h>
	14	#include <linux/interrupt.h>
	15	#include "pci.h"
	16
d71374da	17	DECLARE_RWSEM(pci_bus_sem);
994a65e2	18	/*
45e829ea	19	* find the upstream PCIe-to-PCI bridge of a PCI device
994a65e2	20	* if the device is PCIE, return NULL
45e829ea	21	* if the device isn't connected to a PCIe bridge (that is its parent is a
994a65e2 KA	22	* legacy PCI bridge and the bridge is directly connected to bus 0), return its
	23	* parent
	24	*/
	25	struct pci_dev *
	26	pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
	27	{
	28	struct pci_dev *tmp = NULL;
	29
5f4d91a1	30	if (pci_is_pcie(pdev))
994a65e2 KA	31	return NULL;
994a65e2 KA	32	while (1) {
6e3f36df	33	if (pci_is_root_bus(pdev->bus))
994a65e2 KA	34	break;
	35	pdev = pdev->bus->self;
	36	/* a p2p bridge */
5f4d91a1	37	if (!pci_is_pcie(pdev)) {
994a65e2 KA	38	tmp = pdev;
	39	continue;
	40	}
45e829ea	41	/* PCI device should connect to a PCIe bridge */
994a65e2 KA	42	if (pdev->pcie_type != PCI_EXP_TYPE_PCI_BRIDGE) {
	43	/* Busted hardware? */
	44	WARN_ON_ONCE(1);
	45	return NULL;
	46	}
	47	return pdev;
	48	}
	49
	50	return tmp;
	51	}
1da177e4	52
96bde06a	53	static struct pci_bus pci_do_find_bus(struct pci_bus bus, unsigned char busnr)
1da177e4 LT	54	{
	55	struct pci_bus* child;
	56	struct list_head *tmp;
	57
	58	if(bus->number == busnr)
	59	return bus;
	60
	61	list_for_each(tmp, &bus->children) {
	62	child = pci_do_find_bus(pci_bus_b(tmp), busnr);
	63	if(child)
	64	return child;
	65	}
	66	return NULL;
	67	}
	68
	69	/**
	70	* pci_find_bus - locate PCI bus from a given domain and bus number
	71	* @domain: number of PCI domain to search
	72	* @busnr: number of desired PCI bus
	73	*
	74	* Given a PCI bus number and domain number, the desired PCI bus is located
	75	* in the global list of PCI buses. If the bus is found, a pointer to its
	76	* data structure is returned. If no bus is found, %NULL is returned.
	77	*/
c8439cfc	78	struct pci_bus * pci_find_bus(int domain, int busnr)
1da177e4 LT	79	{
	80	struct pci_bus *bus = NULL;
	81	struct pci_bus *tmp_bus;
	82
	83	while ((bus = pci_find_next_bus(bus)) != NULL) {
	84	if (pci_domain_nr(bus) != domain)
	85	continue;
	86	tmp_bus = pci_do_find_bus(bus, busnr);
	87	if (tmp_bus)
	88	return tmp_bus;
	89	}
	90	return NULL;
	91	}
	92
	93	/**
	94	* pci_find_next_bus - begin or continue searching for a PCI bus
	95	* @from: Previous PCI bus found, or %NULL for new search.
	96	*
	97	* Iterates through the list of known PCI busses. A new search is
d75763d2	98	* initiated by passing %NULL as the @from argument. Otherwise if
1da177e4 LT	99	* @from is not %NULL, searches continue from next device on the
	100	* global list.
	101	*/
	102	struct pci_bus *
	103	pci_find_next_bus(const struct pci_bus *from)
	104	{
	105	struct list_head *n;
	106	struct pci_bus *b = NULL;
	107
	108	WARN_ON(in_interrupt());
d71374da	109	down_read(&pci_bus_sem);
1da177e4 LT	110	n = from ? from->node.next : pci_root_buses.next;
	111	if (n != &pci_root_buses)
	112	b = pci_bus_b(n);
d71374da	113	up_read(&pci_bus_sem);
1da177e4 LT	114	return b;
	115	}
	116
1da177e4 LT	117	/**
	118	* pci_get_slot - locate PCI device for a given PCI slot
	119	* @bus: PCI bus on which desired PCI device resides
	120	* @devfn: encodes number of PCI slot in which the desired PCI
	121	* device resides and the logical device number within that slot
	122	* in case of multi-function devices.
	123	*
	124	* Given a PCI bus and slot/function number, the desired PCI device
	125	* is located in the list of PCI devices.
	126	* If the device is found, its reference count is increased and this
	127	* function returns a pointer to its data structure. The caller must
	128	* decrement the reference count by calling pci_dev_put().
	129	* If no device is found, %NULL is returned.
	130	*/
	131	struct pci_dev * pci_get_slot(struct pci_bus *bus, unsigned int devfn)
	132	{
	133	struct list_head *tmp;
	134	struct pci_dev *dev;
	135
	136	WARN_ON(in_interrupt());
d71374da	137	down_read(&pci_bus_sem);
1da177e4 LT	138
	139	list_for_each(tmp, &bus->devices) {
	140	dev = pci_dev_b(tmp);
	141	if (dev->devfn == devfn)
	142	goto out;
	143	}
	144
	145	dev = NULL;
	146	out:
	147	pci_dev_get(dev);
d71374da	148	up_read(&pci_bus_sem);
1da177e4 LT	149	return dev;
	150	}
	151
29f3eb64	152	/**
3c299dc2 AP	153	* pci_get_domain_bus_and_slot - locate PCI device for a given PCI domain (segment), bus, and slot
	154	* @domain: PCI domain/segment on which the PCI device resides.
	155	* @bus: PCI bus on which desired PCI device resides
	156	* @devfn: encodes number of PCI slot in which the desired PCI device
	157	* resides and the logical device number within that slot in case of
	158	* multi-function devices.
5463d9f0	159	*
3c299dc2 AP	160	* Given a PCI domain, bus, and slot/function number, the desired PCI
	161	* device is located in the list of PCI devices. If the device is
	162	* found, its reference count is increased and this function returns a
	163	* pointer to its data structure. The caller must decrement the
	164	* reference count by calling pci_dev_put(). If no device is found,
	165	* %NULL is returned.
29f3eb64	166	*/
3c299dc2 AP	167	struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus,
3c299dc2 AP	168	unsigned int devfn)
29f3eb64 AC	169	{
	170	struct pci_dev *dev = NULL;
	171
4e344b1c	172	for_each_pci_dev(dev) {
3c299dc2 AP	173	if (pci_domain_nr(dev->bus) == domain &&
3c299dc2 AP	174	(dev->bus->number == bus && dev->devfn == devfn))
29f3eb64 AC	175	return dev;
	176	}
	177	return NULL;
	178	}
3c299dc2	179	EXPORT_SYMBOL(pci_get_domain_bus_and_slot);
29f3eb64	180
95247b57	181	static int match_pci_dev_by_id(struct device dev, void data)
1da177e4	182	{
95247b57 GKH	183	struct pci_dev *pdev = to_pci_dev(dev);
95247b57 GKH	184	struct pci_device_id *id = data;
1da177e4	185
95247b57 GKH	186	if (pci_match_one_device(id, pdev))
	187	return 1;
	188	return 0;
1da177e4 LT	189	}
1da177e4 LT	190
95247b57 GKH	191	/*
	192	* pci_get_dev_by_id - begin or continue searching for a PCI device by id
	193	* @id: pointer to struct pci_device_id to match for the device
1da177e4 LT	194	* @from: Previous PCI device found in search, or %NULL for new search.
1da177e4 LT	195	*
d75763d2	196	* Iterates through the list of known PCI devices. If a PCI device is found
95247b57 GKH	197	* with a matching id a pointer to its device structure is returned, and the
	198	* reference count to the device is incremented. Otherwise, %NULL is returned.
	199	* A new search is initiated by passing %NULL as the @from argument. Otherwise
	200	* if @from is not %NULL, searches continue from next device on the global
	201	* list. The reference count for @from is always decremented if it is not
	202	* %NULL.
	203	*
	204	* This is an internal function for use by the other search functions in
	205	* this file.
1da177e4	206	*/
95247b57	207	static struct pci_dev pci_get_dev_by_id(const struct pci_device_id id,
b08508c4	208	struct pci_dev *from)
1da177e4	209	{
95247b57 GKH	210	struct device *dev;
	211	struct device *dev_start = NULL;
	212	struct pci_dev *pdev = NULL;
	213
	214	WARN_ON(in_interrupt());
c4ed02fa MW	215	if (from)
c4ed02fa MW	216	dev_start = &from->dev;
95247b57 GKH	217	dev = bus_find_device(&pci_bus_type, dev_start, (void *)id,
	218	match_pci_dev_by_id);
	219	if (dev)
	220	pdev = to_pci_dev(dev);
ebca4f1b GKH	221	if (from)
ebca4f1b GKH	222	pci_dev_put(from);
95247b57	223	return pdev;
1da177e4 LT	224	}
	225
	226	/**
	227	* pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
	228	* @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
	229	* @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
	230	* @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
	231	* @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
	232	* @from: Previous PCI device found in search, or %NULL for new search.
	233	*
d75763d2 RD	234	* Iterates through the list of known PCI devices. If a PCI device is found
d75763d2 RD	235	* with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its
1da177e4 LT	236	* device structure is returned, and the reference count to the device is
1da177e4 LT	237	* incremented. Otherwise, %NULL is returned. A new search is initiated by
d75763d2	238	* passing %NULL as the @from argument. Otherwise if @from is not %NULL,
1da177e4 LT	239	* searches continue from next device on the global list.
	240	* The reference count for @from is always decremented if it is not %NULL.
	241	*/
95247b57 GKH	242	struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
95247b57 GKH	243	unsigned int ss_vendor, unsigned int ss_device,
b08508c4	244	struct pci_dev *from)
1da177e4	245	{
95247b57 GKH	246	struct pci_dev *pdev;
95247b57 GKH	247	struct pci_device_id *id;
6ae4adf5 AB	248
6ae4adf5 AB	249	/*
95247b57 GKH	250	* pci_find_subsys() can be called on the ide_setup() path,
	251	* super-early in boot. But the down_read() will enable local
	252	* interrupts, which can cause some machines to crash. So here we
	253	* detect and flag that situation and bail out early.
6ae4adf5	254	*/
35ef63f6	255	if (unlikely(no_pci_devices()))
6ae4adf5	256	return NULL;
95247b57 GKH	257
	258	id = kzalloc(sizeof(*id), GFP_KERNEL);
	259	if (!id)
	260	return NULL;
	261	id->vendor = vendor;
	262	id->device = device;
	263	id->subvendor = ss_vendor;
	264	id->subdevice = ss_device;
	265
	266	pdev = pci_get_dev_by_id(id, from);
	267	kfree(id);
	268
	269	return pdev;
1da177e4 LT	270	}
	271
	272	/**
	273	* pci_get_device - begin or continue searching for a PCI device by vendor/device id
	274	* @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
	275	* @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
	276	* @from: Previous PCI device found in search, or %NULL for new search.
	277	*
	278	* Iterates through the list of known PCI devices. If a PCI device is
	279	* found with a matching @vendor and @device, the reference count to the
	280	* device is incremented and a pointer to its device structure is returned.
	281	* Otherwise, %NULL is returned. A new search is initiated by passing %NULL
d75763d2	282	* as the @from argument. Otherwise if @from is not %NULL, searches continue
1da177e4 LT	283	* from next device on the global list. The reference count for @from is
	284	* always decremented if it is not %NULL.
	285	*/
	286	struct pci_dev *
	287	pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from)
	288	{
	289	return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
	290	}
	291
1da177e4 LT	292	/**
	293	* pci_get_class - begin or continue searching for a PCI device by class
	294	* @class: search for a PCI device with this class designation
	295	* @from: Previous PCI device found in search, or %NULL for new search.
	296	*
	297	* Iterates through the list of known PCI devices. If a PCI device is
	298	* found with a matching @class, the reference count to the device is
	299	* incremented and a pointer to its device structure is returned.
	300	* Otherwise, %NULL is returned.
d75763d2	301	* A new search is initiated by passing %NULL as the @from argument.
1da177e4 LT	302	* Otherwise if @from is not %NULL, searches continue from next device
	303	* on the global list. The reference count for @from is always decremented
	304	* if it is not %NULL.
	305	*/
	306	struct pci_dev pci_get_class(unsigned int class, struct pci_dev from)
	307	{
1da177e4	308	struct pci_dev *dev;
95247b57	309	struct pci_device_id *id;
1da177e4	310
95247b57 GKH	311	id = kzalloc(sizeof(*id), GFP_KERNEL);
	312	if (!id)
	313	return NULL;
	314	id->vendor = id->device = id->subvendor = id->subdevice = PCI_ANY_ID;
	315	id->class_mask = PCI_ANY_ID;
	316	id->class = class;
1da177e4	317
95247b57 GKH	318	dev = pci_get_dev_by_id(id, from);
95247b57 GKH	319	kfree(id);
1da177e4 LT	320	return dev;
	321	}
	322
448432c4 GKH	323	/**
	324	* pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
	325	* @ids: A pointer to a null terminated list of struct pci_device_id structures
	326	* that describe the type of PCI device the caller is trying to find.
	327	*
	328	* Obvious fact: You do not have a reference to any device that might be found
	329	* by this function, so if that device is removed from the system right after
	330	* this function is finished, the value will be stale. Use this function to
	331	* find devices that are usually built into a system, or for a general hint as
	332	* to if another device happens to be present at this specific moment in time.
	333	*/
	334	int pci_dev_present(const struct pci_device_id *ids)
d86f90f9	335	{
95247b57	336	struct pci_dev *found = NULL;
d86f90f9 AC	337
d86f90f9 AC	338	WARN_ON(in_interrupt());
d86f90f9	339	while (ids->vendor \|\| ids->subvendor \|\| ids->class_mask) {
95247b57 GKH	340	found = pci_get_dev_by_id(ids, NULL);
	341	if (found)
	342	goto exit;
d86f90f9 AC	343	ids++;
d86f90f9 AC	344	}
3c92c57a	345	exit:
448432c4 GKH	346	if (found)
	347	return 1;
	348	return 0;
1da177e4 LT	349	}
	350	EXPORT_SYMBOL(pci_dev_present);
	351
29f3eb64 AC	352	/* For boot time work */
	353	EXPORT_SYMBOL(pci_find_bus);
	354	EXPORT_SYMBOL(pci_find_next_bus);
	355	/* For everyone */
1da177e4 LT	356	EXPORT_SYMBOL(pci_get_device);
	357	EXPORT_SYMBOL(pci_get_subsys);
	358	EXPORT_SYMBOL(pci_get_slot);
	359	EXPORT_SYMBOL(pci_get_class);