Implement 'map_peer_resource' for the Intel IOMMU driver. Simply translate
the resource to a physical address and route it to the same handlers used
by the 'map_page' API.
This allows a device to map another's resource, to enable peer-to-peer
transactions.
Add behind CONFIG_HAS_DMA_P2P guards, since the dma_map_ops members are
behind them as well.
Signed-off-by: Will Davis <wdavis@xxxxxxxxxx>
Reviewed-by: Terence Ripperda <tripperda@xxxxxxxxxx>
Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
---
drivers/iommu/intel-iommu.c | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index a98a7b2..0d3746f 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3544,6 +3544,40 @@ static void intel_unmap_page(struct device *dev, dma_addr_t dev_addr,
intel_unmap(dev, dev_addr);
}
+#ifdef CONFIG_HAS_DMA_P2P
+static dma_peer_addr_t intel_map_peer_resource(struct device *dev,
+ struct device *peer,
+ struct resource *res,
+ unsigned long offset,
+ size_t size,
+ enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ struct pci_dev *pdev;
+ struct pci_dev *ppeer;
+
+ if (!dev_is_pci(dev) || !dev_is_pci(peer))
+ return 0;
+
+ pdev = to_pci_dev(dev);
+ ppeer = to_pci_dev(peer);
+
+ if (!pci_peer_traffic_supported(pdev, ppeer))
+ return 0;
+
+ return __intel_map_single(dev, res->start + offset, size,
+ dir, *dev->dma_mask);
+}
+
+static void intel_unmap_peer_resource(struct device *dev,
+ dma_peer_addr_t dev_addr,
+ size_t size, enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ intel_unmap(dev, dev_addr);
+}
+#endif
+
static void *intel_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t flags,
struct dma_attrs *attrs)
@@ -3700,6 +3734,10 @@ struct dma_map_ops intel_dma_ops = {
.unmap_sg = intel_unmap_sg,
.map_page = intel_map_page,
.unmap_page = intel_unmap_page,
+#ifdef CONFIG_HAS_DMA_P2P
+ .map_peer_resource = intel_map_peer_resource,
+ .unmap_peer_resource = intel_unmap_peer_resource,
+#endif
.mapping_error = intel_mapping_error,
};
--
2.5.1
--
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