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authorAlex Williamson <alex.williamson@redhat.com>2014-05-22 17:07:30 -0600
committerBjorn Helgaas <bhelgaas@google.com>2014-05-28 11:46:24 -0600
commitc25dc82899e67a32fdcfb20dd72a37fc236fde2e (patch)
tree5db0bd880c1b2fbfb3435e68b991216e2a770cf2 /include/linux/pci.h
parentc9eaa447e77efe77b7fa4c953bd62de8297fd6c5 (diff)
PCI: Add DMA alias iterator
In a mixed PCI/PCI-X/PCIe topology, bridges can take ownership of transactions, replacing the original requester ID with their own. Sometimes we just want to know the resulting device or resulting alias; other times we want each step in the chain. This iterator allows either usage. When an endpoint is connected via an unbroken chain of PCIe switches and root ports, it has no alias and its requester ID is visible to the root bus. When PCI/X get in the way, we pick up aliases for bridges. The reason why we potentially care about each step in the path is because of PCI-X. PCI-X has the concept of a requester ID, but bridges may or may not take ownership of various types of transactions. We therefore leave it to the consumer of this function to prune out what they don't care about rather than attempt to flatten the alias ourselves. Tested-by: George Spelvin <linux@horizon.com> Tested-by: Pat Erley <pat-lkml@erley.org> Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'include/linux/pci.h')
-rw-r--r--include/linux/pci.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/linux/pci.h b/include/linux/pci.h
index aab57b4abe7..14b074bbc84 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1795,6 +1795,10 @@ static inline struct eeh_dev *pci_dev_to_eeh_dev(struct pci_dev *pdev)
}
#endif
+int pci_for_each_dma_alias(struct pci_dev *pdev,
+ int (*fn)(struct pci_dev *pdev,
+ u16 alias, void *data), void *data);
+
/**
* pci_find_upstream_pcie_bridge - find upstream PCIe-to-PCI bridge of a device
* @pdev: the PCI device