// SPDX-License-Identifier: GPL-2.0
/*
* 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/pci.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include "pci.h"
DECLARE_RWSEM(pci_bus_sem);
/*
* pci_for_each_dma_alias - Iterate over DMA aliases for a device
* @pdev: starting downstream device
* @fn: function to call for each alias
* @data: opaque data to pass to @fn
*
* Starting @pdev, walk up the bus calling @fn for each possible alias
* of @pdev at the root bus.
*/
int pci_for_each_dma_alias(struct pci_dev *pdev,
int (*fn)(struct pci_dev *pdev,
u16 alias, void *data), void *data)
{
struct pci_bus *bus;
int ret;
/*
* The device may have an explicit alias requester ID for DMA where the
* requester is on another PCI bus.
*/
pdev = pci_real_dma_dev(pdev);
ret = fn(pdev, pci_dev_id(pdev), data);
if (ret)
return ret;
/*
* If the device is broken and uses an alias requester ID for
* DMA, iterate over that too.
*/
if (unlikely(pdev->dma_alias_mask)) {
unsigned int devfn;
for_each_set_bit(devfn, pdev->dma_alias_mask, MAX_NR_DEVFNS) {
ret = fn(pdev, PCI_DEVID(pdev->bus->number, devfn),
data);
if (ret)
return ret;
}
}
for (bus = pdev->bus; !pci_is_root_bus(bus); bus = bus->parent) {
struct pci_dev *tmp;
/* Skip virtual buses */
if (!bus->self)
continue;
tmp = bus->self;
/* stop at bridge where translation unit is associated */
if (tmp->dev_flags & PCI_DEV_FLAGS_BRIDGE_XLATE_ROOT)
return ret;
/*
* PCIe-to-PCI/X bridges alias transactions from downstream
* devices using the subordinate bus number (PCI Express to
* PCI/PCI-X Bridge Spec, rev 1.0, sec 2.3). For all cases
* where the upstream bus is PCI/X we alias to the bridge
* (there are various conditions in the previous reference
* where the bridge may take ownership of transactions, even
* when the secondary interface is PCI-X).
*/
if (pci_is_pcie(tmp)) {
switch (pci_pcie_type(tmp)) {
case PCI_EXP_TYPE_ROOT_PORT:
case PCI_EXP_TYPE_UPSTREAM:
case PCI_EXP_TYPE_DOWNSTREAM:
continue;
case PCI_EXP_TYPE_PCI_BRIDGE:
ret = fn(tmp,
PCI_DEVID(tmp->subordinate->number,
PCI_DEVFN(0, 0)), data);
if (ret)
return ret;
continue;
case PCI_EXP_TYPE_PCIE_BRIDGE:
ret = fn(tmp, pci_dev_id(tmp), data);
if (ret)
return ret;
continue;
}
} else {
if (tmp->dev_flags & PCI_DEV_FLAG_PCIE_BRIDGE_ALIAS)
ret = fn(tmp,
PCI_DEVID(tmp->subordinate->number,
PCI_DEVFN(0, 0)), data);
else
ret = fn(tmp, pci_dev_id(tmp), data);
if (ret)
return ret;
}
}
return ret;
}
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;
}
EXPORT_SYMBOL(pci_find_bus);
/**
* 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;
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;
}
EXPORT_SYMBOL(pci_find_next_bus);
/**
* 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;
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;
}
EXPORT_SYMBOL(pci_get_slot);
/**
* 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, const void *data)
{
struct pci_dev *pdev = to_pci_dev(dev);
const 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;
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);
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);
}
EXPORT_SYMBOL(pci_get_subsys);
/**
* 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);
}
EXPORT_SYMBOL(pci_get_device);
/**
* 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);
}
EXPORT_SYMBOL(pci_get_class);
/**
* pci_get_base_class - searching for a PCI device by matching against the base class code only
* @class: search for a PCI device with this base class code
* @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 base class code, the reference count to the device is
* incremented. See pci_match_one_device() to figure out how does this works.
* 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.
*
* Returns:
* A pointer to a matched PCI device, %NULL Otherwise.
*/
struct pci_dev *pci_get_base_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 = 0xFF0000,
.class = class << 16,
};
return pci_get_dev_by_id(&id, from);
}
EXPORT_SYMBOL(pci_get_base_class);
/**
* 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;
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);
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