From: Jérôme Glisse <jglisse@xxxxxxxxxx>
Some device like GPU do things differently if swiotlb is in use. We
use to rely on swiotlb_nr_tbl() to know if swiotlb was enabled or not
but this is unreliable. Patch add a simple helpers to check if any of
the dma_ops associated with a device points to the swiotlb functions,
making swiotlb check reliable for a device.
Signed-off-by: Jérôme Glisse <jglisse@xxxxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: Ben Skeggs <bskeggs@xxxxxxxxxx>
Cc: Dave Airlie <airlied@xxxxxxxxxx>
Cc: lkml@xxxxxxxxxxxxxxx
Cc: Daniel Vetter <daniel.vetter@xxxxxxxxx>
---
include/linux/dma-mapping.h | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index ac07ff0..eac911e 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -314,4 +314,22 @@ static inline int dma_mmap_writecombine(struct device *dev,
#define dma_unmap_len_set(PTR, LEN_NAME, VAL) do { } while (0)
#endif
+
+#ifdef CONFIG_SWIOTLB
+static inline bool swiotlb_in_use(struct device *dev)
+{
+ struct dma_map_ops *ops = get_dma_ops(dev);
+
+ return (ops->map_sg == swiotlb_map_sg_attrs ||
+ ops->unmap_sg == swiotlb_unmap_sg_attrs ||
+ ops->map_page == swiotlb_map_page);
+}
+#else
+static inline bool swiotlb_in_use(struct device *dev)
+{
+ return false;
+}
+#endif
+
+
#endif
--
2.1.0
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