Add swiotlb stub of the 'map_peer_resource' DMA operation.
Signed-off-by: Will Davis <wdavis@xxxxxxxxxx>
---
include/linux/swiotlb.h | 8 ++++++++
lib/swiotlb.c | 17 +++++++++++++++++
2 files changed, 25 insertions(+)
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index e7a018e..872463a 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -87,6 +87,14 @@ swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
int nelems, enum dma_data_direction dir,
struct dma_attrs *attrs);
+#ifdef CONFIG_HAS_DMA_P2P
+extern dma_peer_addr_t
+swiotlb_map_peer_resource(struct device *hwdev, struct device *hwpeer,
+ struct resource *res, unsigned long offset,
+ size_t size, enum dma_data_direction dir,
+ struct dma_attrs *attrs);
+#endif
+
extern void
swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
size_t size, enum dma_data_direction dir);
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 76f29ec..61522a7 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -945,6 +945,23 @@ swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
}
EXPORT_SYMBOL(swiotlb_unmap_sg);
+#ifdef CONFIG_HAS_DMA_P2P
+/*
+ * Maps a single region from a peer device's resource for DMA streaming. This
+ * is currently unimplemented because there's no bounce buffer abstraction for
+ * peer mappings.
+ */
+dma_peer_addr_t
+swiotlb_map_peer_resource(struct device *hwdev, struct device *hwpeer,
+ struct resource *res, unsigned long offset,
+ size_t size, enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ return phys_to_dma(hwdev, io_tlb_overflow_buffer);
+}
+EXPORT_SYMBOL(swiotlb_map_peer_resource);
+#endif
+
/*
* Make physical memory consistent for a set of streaming mode DMA translations
* after a transfer.
--
2.5.1
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