- 根目录:
- 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/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);