Add functions to DMA-map and -unmap a peer device's resource for a given
device. This will allow devices to DMA-map, for example, another device's
BAR region on PCI to enable peer-to-peer transactions.
Guard these new functions behind CONFIG_HAS_DMA_P2P.
Signed-off-by: Will Davis <wdavis@xxxxxxxxxx>
---
include/asm-generic/dma-mapping-common.h | 43 ++++++++++++++++++++++++++++++++
include/linux/dma-mapping.h | 12 +++++++++
2 files changed, 55 insertions(+)
diff --git a/include/asm-generic/dma-mapping-common.h b/include/asm-generic/dma-mapping-common.h
index 940d5ec..45eec17 100644
--- a/include/asm-generic/dma-mapping-common.h
+++ b/include/asm-generic/dma-mapping-common.h
@@ -73,6 +73,42 @@ static inline void dma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg
ops->unmap_sg(dev, sg, nents, dir, attrs);
}
+#ifdef CONFIG_HAS_DMA_P2P
+static inline dma_peer_addr_t dma_map_peer_resource_attrs(struct device *dev,
+ struct device *peer,
+ struct resource *res,
+ size_t offset,
+ size_t size,
+ enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ struct dma_map_ops *ops = get_dma_ops(dev);
+ dma_peer_addr_t addr;
+
+ BUG_ON(!valid_dma_direction(dir));
+ BUG_ON(ops->map_peer_resource == NULL);
+ addr = ops->map_peer_resource(dev, peer, res, offset, size, dir,
+ attrs);
+ debug_dma_map_peer_resource(dev, peer, res, offset, size, dir, addr);
+
+ return addr;
+}
+
+static inline void dma_unmap_peer_resource_attrs(struct device *dev,
+ dma_peer_addr_t addr,
+ size_t size,
+ enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ struct dma_map_ops *ops = get_dma_ops(dev);
+
+ BUG_ON(!valid_dma_direction(dir));
+ if (ops->unmap_peer_resource)
+ ops->unmap_peer_resource(dev, addr, size, dir, attrs);
+ debug_dma_unmap_peer_resource(dev, addr, size, dir);
+}
+#endif
+
static inline dma_addr_t dma_map_page(struct device *dev, struct page *page,
size_t offset, size_t size,
enum dma_data_direction dir)
@@ -181,6 +217,13 @@ dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
#define dma_map_sg(d, s, n, r) dma_map_sg_attrs(d, s, n, r, NULL)
#define dma_unmap_sg(d, s, n, r) dma_unmap_sg_attrs(d, s, n, r, NULL)
+#ifdef CONFIG_HAS_DMA_P2P
+#define dma_map_peer_resource(d, p, e, o, s, r) \
+ dma_map_peer_resource_attrs(d, p, e, o, s, r, NULL)
+#define dma_unmap_peer_resource(d, a, s, r) \
+ dma_unmap_peer_resource_attrs(d, a, s, r, NULL)
+#endif
+
extern int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
void *cpu_addr, dma_addr_t dma_addr, size_t size);
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index ac07ff0..7b8fddc 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -34,6 +34,18 @@ struct dma_map_ops {
void (*unmap_page)(struct device *dev, dma_addr_t dma_handle,
size_t size, enum dma_data_direction dir,
struct dma_attrs *attrs);
+#ifdef CONFIG_HAS_DMA_P2P
+ dma_peer_addr_t (*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);
+ void (*unmap_peer_resource)(struct device *dev,
+ dma_peer_addr_t dma_handle,
+ size_t size, enum dma_data_direction dir,
+ struct dma_attrs *attrs);
+#endif
/*
* map_sg returns 0 on error and a value > 0 on success.
* It should never return a value < 0.
--
2.5.0
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