[PATCH 10/22] PCI: Add pci_resource_to_peer()

[Will Davis <wdavis@xxxxxxxxxx>]

Add helper to convert a struct resource to a peer DMA address.

Signed-off-by: Will Davis <wdavis@xxxxxxxxxx>
---
 include/linux/pci.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/include/linux/pci.h b/include/linux/pci.h
index db0cb51..2a9deff 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1508,6 +1508,22 @@ static inline void pci_resource_to_user(const struct pci_dev *dev, int bar,
 }
 #endif /* HAVE_ARCH_PCI_RESOURCE_TO_USER */
 
+#ifdef CONFIG_HAS_DMA_P2P
+static inline bool pci_resource_to_peer(struct pci_dev *dev,
+					struct pci_dev *peer,
+					struct resource *res,
+					dma_peer_addr_t *peer_addr) {
+	if (pci_peer_traffic_supported(dev, peer)) {
+		struct pci_bus_region region;
+
+		pcibios_resource_to_bus(dev->bus, &region, res);
+		*peer_addr = region.start;
+		return true;
+	}
+
+	return false;
+}
+#endif /* CONFIG_HAS_DMA_P2P */
 
 /*
  *  The world is not perfect and supplies us with broken PCI devices.
-- 
2.5.1

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