[PATCH v2 6/7] iommu/vt-d: implement (un)map_resource

[<wdavis@nvidia.com>]

From: Will Davis <wdavis@nvidia.com>

Implement 'map_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.

Signed-off-by: Will Davis <wdavis@nvidia.com>
Reviewed-by: Terence Ripperda <tripperda@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
---
 drivers/iommu/intel-iommu.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 68d43be..0f49eff 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3095,6 +3095,15 @@ static dma_addr_t intel_map_page(struct device *dev, struct page *page,
 				  dir, *dev->dma_mask);
 }
 
+static dma_addr_t intel_map_resource(struct device *dev, struct resource *res,
+				     unsigned long offset, size_t size,
+				     enum dma_data_direction dir,
+				     struct dma_attrs *attrs)
+{
+	return __intel_map_single(dev, res->start + offset, size,
+				  dir, *dev->dma_mask);
+}
+
 static void flush_unmaps(void)
 {
 	int i, j;
@@ -3226,6 +3235,13 @@ static void intel_unmap_page(struct device *dev, dma_addr_t dev_addr,
 	intel_unmap(dev, dev_addr);
 }
 
+static void intel_unmap_resource(struct device *dev, dma_addr_t dev_addr,
+				 size_t size, enum dma_data_direction dir,
+				 struct dma_attrs *attrs)
+{
+	intel_unmap(dev, dev_addr);
+}
+
 static void *intel_alloc_coherent(struct device *dev, size_t size,
 				  dma_addr_t *dma_handle, gfp_t flags,
 				  struct dma_attrs *attrs)
@@ -3382,6 +3398,8 @@ struct dma_map_ops intel_dma_ops = {
 	.unmap_sg = intel_unmap_sg,
 	.map_page = intel_map_page,
 	.unmap_page = intel_unmap_page,
+	.map_resource = intel_map_resource,
+	.unmap_resource = intel_unmap_resource,
 	.mapping_error = intel_mapping_error,
 };
 
-- 
2.4.0