[mirror_ubuntu-zesty-kernel.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 <mj@ucw.cz>
 *	Copyright (C) 2003 -- 2004 Greg Kroah-Hartman <greg@kroah.com>
 */

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

DECLARE_RWSEM(pci_bus_sem);
EXPORT_SYMBOL_GPL(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 (pci_pcie_type(pdev) != 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 pci_bus *tmp;

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

	list_for_each_entry(tmp, &bus->children, node) {
		child = pci_do_find_bus(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 buses.  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 = list_entry(n, struct pci_bus, node);
	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 pci_dev *dev;

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

	list_for_each_entry(dev, &bus->devices, bus_list) {
		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_device_id id = {
		.vendor = vendor,
		.device = device,
		.subvendor = ss_vendor,
		.subdevice = ss_device,
	};

	return pci_get_dev_by_id(&id, from);
}

/**
 * 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_device_id id = {
		.vendor = PCI_ANY_ID,
		.device = PCI_ANY_ID,
		.subvendor = PCI_ANY_ID,
		.subdevice = PCI_ANY_ID,
		.class_mask = PCI_ANY_ID,
		.class = class,
	};

	return pci_get_dev_by_id(&id, from);
}

/**
 * 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) {
			pci_dev_put(found);
			return 1;
		}
		ids++;
	}

	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	1	/*
f7625980	2	* PCI searching functions.
1da177e4 LT	3	*
	4	* Copyright (C) 1993 -- 1997 Drew Eckhardt, Frederic Potter,
	5	* David Mosberger-Tang
	6	* Copyright (C) 1997 -- 2000 Martin Mares <mj@ucw.cz>
	7	* Copyright (C) 2003 -- 2004 Greg Kroah-Hartman <greg@kroah.com>
	8	*/
	9
1da177e4	10	#include <linux/pci.h>
5a0e3ad6	11	#include <linux/slab.h>
1da177e4 LT	12	#include <linux/module.h>
	13	#include <linux/interrupt.h>
	14	#include "pci.h"
	15
d71374da	16	DECLARE_RWSEM(pci_bus_sem);
ce29ca3e AK	17	EXPORT_SYMBOL_GPL(pci_bus_sem);
ce29ca3e AK	18
994a65e2	19	/*
45e829ea	20	* find the upstream PCIe-to-PCI bridge of a PCI device
994a65e2	21	* if the device is PCIE, return NULL
45e829ea	22	* if the device isn't connected to a PCIe bridge (that is its parent is a
994a65e2 KA	23	* legacy PCI bridge and the bridge is directly connected to bus 0), return its
	24	* parent
	25	*/
	26	struct pci_dev *
	27	pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
	28	{
	29	struct pci_dev *tmp = NULL;
	30
5f4d91a1	31	if (pci_is_pcie(pdev))
994a65e2 KA	32	return NULL;
994a65e2 KA	33	while (1) {
6e3f36df	34	if (pci_is_root_bus(pdev->bus))
994a65e2 KA	35	break;
	36	pdev = pdev->bus->self;
	37	/* a p2p bridge */
5f4d91a1	38	if (!pci_is_pcie(pdev)) {
994a65e2 KA	39	tmp = pdev;
	40	continue;
	41	}
45e829ea	42	/* PCI device should connect to a PCIe bridge */
62f87c0e	43	if (pci_pcie_type(pdev) != PCI_EXP_TYPE_PCI_BRIDGE) {
994a65e2 KA	44	/* Busted hardware? */
	45	WARN_ON_ONCE(1);
	46	return NULL;
	47	}
	48	return pdev;
	49	}
	50
	51	return tmp;
	52	}
1da177e4	53
96bde06a	54	static struct pci_bus pci_do_find_bus(struct pci_bus bus, unsigned char busnr)
1da177e4	55	{
94e6a9b9 YW	56	struct pci_bus *child;
94e6a9b9 YW	57	struct pci_bus *tmp;
1da177e4 LT	58
	59	if(bus->number == busnr)
	60	return bus;
	61
94e6a9b9 YW	62	list_for_each_entry(tmp, &bus->children, node) {
94e6a9b9 YW	63	child = pci_do_find_bus(tmp, busnr);
1da177e4 LT	64	if(child)
	65	return child;
	66	}
	67	return NULL;
	68	}
	69
	70	/**
	71	* pci_find_bus - locate PCI bus from a given domain and bus number
	72	* @domain: number of PCI domain to search
	73	* @busnr: number of desired PCI bus
	74	*
	75	* Given a PCI bus number and domain number, the desired PCI bus is located
	76	* in the global list of PCI buses. If the bus is found, a pointer to its
	77	* data structure is returned. If no bus is found, %NULL is returned.
	78	*/
c8439cfc	79	struct pci_bus * pci_find_bus(int domain, int busnr)
1da177e4 LT	80	{
	81	struct pci_bus *bus = NULL;
	82	struct pci_bus *tmp_bus;
	83
	84	while ((bus = pci_find_next_bus(bus)) != NULL) {
	85	if (pci_domain_nr(bus) != domain)
	86	continue;
	87	tmp_bus = pci_do_find_bus(bus, busnr);
	88	if (tmp_bus)
	89	return tmp_bus;
	90	}
	91	return NULL;
	92	}
	93
	94	/**
	95	* pci_find_next_bus - begin or continue searching for a PCI bus
	96	* @from: Previous PCI bus found, or %NULL for new search.
	97	*
f7625980	98	* Iterates through the list of known PCI buses. A new search is
d75763d2	99	* initiated by passing %NULL as the @from argument. Otherwise if
1da177e4 LT	100	* @from is not %NULL, searches continue from next device on the
	101	* global list.
	102	*/
f7625980	103	struct pci_bus *
1da177e4 LT	104	pci_find_next_bus(const struct pci_bus *from)
	105	{
	106	struct list_head *n;
	107	struct pci_bus *b = NULL;
	108
	109	WARN_ON(in_interrupt());
d71374da	110	down_read(&pci_bus_sem);
1da177e4 LT	111	n = from ? from->node.next : pci_root_buses.next;
1da177e4 LT	112	if (n != &pci_root_buses)
94e6a9b9	113	b = list_entry(n, struct pci_bus, node);
d71374da	114	up_read(&pci_bus_sem);
1da177e4 LT	115	return b;
	116	}
	117
1da177e4 LT	118	/**
	119	* pci_get_slot - locate PCI device for a given PCI slot
	120	* @bus: PCI bus on which desired PCI device resides
f7625980 BH	121	* @devfn: encodes number of PCI slot in which the desired PCI
f7625980 BH	122	* device resides and the logical device number within that slot
1da177e4 LT	123	* in case of multi-function devices.
1da177e4 LT	124	*
f7625980	125	* Given a PCI bus and slot/function number, the desired PCI device
1da177e4 LT	126	* is located in the list of PCI devices.
	127	* If the device is found, its reference count is increased and this
	128	* function returns a pointer to its data structure. The caller must
	129	* decrement the reference count by calling pci_dev_put().
	130	* If no device is found, %NULL is returned.
	131	*/
66455f54	132	struct pci_dev pci_get_slot(struct pci_bus bus, unsigned int devfn)
1da177e4	133	{
1da177e4 LT	134	struct pci_dev *dev;
	135
	136	WARN_ON(in_interrupt());
d71374da	137	down_read(&pci_bus_sem);
1da177e4	138
66455f54	139	list_for_each_entry(dev, &bus->devices, bus_list) {
1da177e4 LT	140	if (dev->devfn == devfn)
	141	goto out;
	142	}
	143
	144	dev = NULL;
	145	out:
	146	pci_dev_get(dev);
d71374da	147	up_read(&pci_bus_sem);
1da177e4 LT	148	return dev;
	149	}
	150
29f3eb64	151	/**
3c299dc2 AP	152	* pci_get_domain_bus_and_slot - locate PCI device for a given PCI domain (segment), bus, and slot
	153	* @domain: PCI domain/segment on which the PCI device resides.
	154	* @bus: PCI bus on which desired PCI device resides
	155	* @devfn: encodes number of PCI slot in which the desired PCI device
	156	* resides and the logical device number within that slot in case of
	157	* multi-function devices.
5463d9f0	158	*
3c299dc2 AP	159	* Given a PCI domain, bus, and slot/function number, the desired PCI
	160	* device is located in the list of PCI devices. If the device is
	161	* found, its reference count is increased and this function returns a
	162	* pointer to its data structure. The caller must decrement the
	163	* reference count by calling pci_dev_put(). If no device is found,
	164	* %NULL is returned.
29f3eb64	165	*/
3c299dc2 AP	166	struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus,
3c299dc2 AP	167	unsigned int devfn)
29f3eb64 AC	168	{
	169	struct pci_dev *dev = NULL;
	170
4e344b1c	171	for_each_pci_dev(dev) {
3c299dc2 AP	172	if (pci_domain_nr(dev->bus) == domain &&
3c299dc2 AP	173	(dev->bus->number == bus && dev->devfn == devfn))
29f3eb64 AC	174	return dev;
	175	}
	176	return NULL;
	177	}
3c299dc2	178	EXPORT_SYMBOL(pci_get_domain_bus_and_slot);
29f3eb64	179
95247b57	180	static int match_pci_dev_by_id(struct device dev, void data)
1da177e4	181	{
95247b57 GKH	182	struct pci_dev *pdev = to_pci_dev(dev);
95247b57 GKH	183	struct pci_device_id *id = data;
1da177e4	184
95247b57 GKH	185	if (pci_match_one_device(id, pdev))
	186	return 1;
	187	return 0;
1da177e4 LT	188	}
1da177e4 LT	189
95247b57 GKH	190	/*
	191	* pci_get_dev_by_id - begin or continue searching for a PCI device by id
	192	* @id: pointer to struct pci_device_id to match for the device
1da177e4 LT	193	* @from: Previous PCI device found in search, or %NULL for new search.
1da177e4 LT	194	*
d75763d2	195	* Iterates through the list of known PCI devices. If a PCI device is found
95247b57 GKH	196	* with a matching id a pointer to its device structure is returned, and the
	197	* reference count to the device is incremented. Otherwise, %NULL is returned.
	198	* A new search is initiated by passing %NULL as the @from argument. Otherwise
	199	* if @from is not %NULL, searches continue from next device on the global
	200	* list. The reference count for @from is always decremented if it is not
	201	* %NULL.
	202	*
	203	* This is an internal function for use by the other search functions in
	204	* this file.
1da177e4	205	*/
95247b57	206	static struct pci_dev pci_get_dev_by_id(const struct pci_device_id id,
b08508c4	207	struct pci_dev *from)
1da177e4	208	{
95247b57 GKH	209	struct device *dev;
	210	struct device *dev_start = NULL;
	211	struct pci_dev *pdev = NULL;
	212
	213	WARN_ON(in_interrupt());
c4ed02fa MW	214	if (from)
c4ed02fa MW	215	dev_start = &from->dev;
95247b57 GKH	216	dev = bus_find_device(&pci_bus_type, dev_start, (void *)id,
	217	match_pci_dev_by_id);
	218	if (dev)
	219	pdev = to_pci_dev(dev);
ebca4f1b GKH	220	if (from)
ebca4f1b GKH	221	pci_dev_put(from);
95247b57	222	return pdev;
1da177e4 LT	223	}
	224
	225	/**
	226	* pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
	227	* @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
	228	* @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
	229	* @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
	230	* @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
	231	* @from: Previous PCI device found in search, or %NULL for new search.
	232	*
d75763d2 RD	233	* Iterates through the list of known PCI devices. If a PCI device is found
d75763d2 RD	234	* with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its
1da177e4 LT	235	* device structure is returned, and the reference count to the device is
1da177e4 LT	236	* incremented. Otherwise, %NULL is returned. A new search is initiated by
d75763d2	237	* passing %NULL as the @from argument. Otherwise if @from is not %NULL,
1da177e4 LT	238	* searches continue from next device on the global list.
	239	* The reference count for @from is always decremented if it is not %NULL.
	240	*/
95247b57 GKH	241	struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
95247b57 GKH	242	unsigned int ss_vendor, unsigned int ss_device,
b08508c4	243	struct pci_dev *from)
1da177e4	244	{
b9443f40 FT	245	struct pci_device_id id = {
	246	.vendor = vendor,
	247	.device = device,
	248	.subvendor = ss_vendor,
	249	.subdevice = ss_device,
	250	};
6ae4adf5	251
b9443f40	252	return pci_get_dev_by_id(&id, from);
1da177e4 LT	253	}
	254
	255	/**
	256	* pci_get_device - begin or continue searching for a PCI device by vendor/device id
	257	* @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
	258	* @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
	259	* @from: Previous PCI device found in search, or %NULL for new search.
	260	*
	261	* Iterates through the list of known PCI devices. If a PCI device is
	262	* found with a matching @vendor and @device, the reference count to the
	263	* device is incremented and a pointer to its device structure is returned.
	264	* Otherwise, %NULL is returned. A new search is initiated by passing %NULL
d75763d2	265	* as the @from argument. Otherwise if @from is not %NULL, searches continue
1da177e4 LT	266	* from next device on the global list. The reference count for @from is
	267	* always decremented if it is not %NULL.
	268	*/
	269	struct pci_dev *
	270	pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from)
	271	{
	272	return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
	273	}
	274
1da177e4 LT	275	/**
	276	* pci_get_class - begin or continue searching for a PCI device by class
	277	* @class: search for a PCI device with this class designation
	278	* @from: Previous PCI device found in search, or %NULL for new search.
	279	*
	280	* Iterates through the list of known PCI devices. If a PCI device is
	281	* found with a matching @class, the reference count to the device is
	282	* incremented and a pointer to its device structure is returned.
	283	* Otherwise, %NULL is returned.
d75763d2	284	* A new search is initiated by passing %NULL as the @from argument.
1da177e4 LT	285	* Otherwise if @from is not %NULL, searches continue from next device
	286	* on the global list. The reference count for @from is always decremented
	287	* if it is not %NULL.
	288	*/
	289	struct pci_dev pci_get_class(unsigned int class, struct pci_dev from)
	290	{
b9443f40 FT	291	struct pci_device_id id = {
	292	.vendor = PCI_ANY_ID,
	293	.device = PCI_ANY_ID,
	294	.subvendor = PCI_ANY_ID,
	295	.subdevice = PCI_ANY_ID,
	296	.class_mask = PCI_ANY_ID,
	297	.class = class,
	298	};
	299
	300	return pci_get_dev_by_id(&id, from);
1da177e4 LT	301	}
1da177e4 LT	302
448432c4 GKH	303	/**
	304	* pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
	305	* @ids: A pointer to a null terminated list of struct pci_device_id structures
	306	* that describe the type of PCI device the caller is trying to find.
	307	*
	308	* Obvious fact: You do not have a reference to any device that might be found
	309	* by this function, so if that device is removed from the system right after
	310	* this function is finished, the value will be stale. Use this function to
	311	* find devices that are usually built into a system, or for a general hint as
	312	* to if another device happens to be present at this specific moment in time.
	313	*/
	314	int pci_dev_present(const struct pci_device_id *ids)
d86f90f9	315	{
95247b57	316	struct pci_dev *found = NULL;
d86f90f9 AC	317
d86f90f9 AC	318	WARN_ON(in_interrupt());
d86f90f9	319	while (ids->vendor \|\| ids->subvendor \|\| ids->class_mask) {
95247b57	320	found = pci_get_dev_by_id(ids, NULL);
d5af7d98 JL	321	if (found) {
	322	pci_dev_put(found);
	323	return 1;
	324	}
d86f90f9 AC	325	ids++;
d86f90f9 AC	326	}
d5af7d98	327
448432c4	328	return 0;
1da177e4 LT	329	}
	330	EXPORT_SYMBOL(pci_dev_present);
	331
29f3eb64 AC	332	/* For boot time work */
	333	EXPORT_SYMBOL(pci_find_bus);
	334	EXPORT_SYMBOL(pci_find_next_bus);
	335	/* For everyone */
1da177e4 LT	336	EXPORT_SYMBOL(pci_get_device);
	337	EXPORT_SYMBOL(pci_get_subsys);
	338	EXPORT_SYMBOL(pci_get_slot);
	339	EXPORT_SYMBOL(pci_get_class);