/* * PCI searching functions. * * Copyright (C) 1993 -- 1997 Drew Eckhardt, Frederic Potter, * David Mosberger-Tang * Copyright (C) 1997 -- 2000 Martin Mares * Copyright (C) 2003 -- 2004 Greg Kroah-Hartman */ #include #include #include #include #include "pci.h" DECLARE_RWSEM(pci_bus_sem); EXPORT_SYMBOL_GPL(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; ret = fn(pdev, PCI_DEVID(pdev->bus->number, pdev->devfn), 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->dev_flags & PCI_DEV_FLAGS_DMA_ALIAS_DEVFN)) { ret = fn(pdev, PCI_DEVID(pdev->bus->number, pdev->dma_alias_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; /* * 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_DEVID(tmp->bus->number, tmp->devfn), 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_DEVID(tmp->bus->number, tmp->devfn), 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; 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; } 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 call