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committed df62ab5e0f7 * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id// 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 <mj@ucw.cz> * Copyright (C) 2003 -- 2004 Greg Kroah-Hartman <greg@kroah.com> */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->dma_alias_mask)) { u8 devfn; for_each_set_bit(devfn, pdev->dma_alias_mask, U8_MAX) { 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_DEVID(tmp->bus->number,