dma-debug: add function to dump dma mappings

This adds a function to dump the DMA mappings that the debugging code is
aware of -- either for a single device, or for _all_ devices.

This can be useful for debugging -- sticking a call to it in the DMA
page fault handler, for example, to see if the faulting address _should_
be mapped or not, and hence work out whether it's IOMMU bugs we're
seeing, or driver bugs.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/dma-debug.h b/include/linux/dma-debug.h
index 4985c6c5237e..46a11c10da04 100644
--- a/include/linux/dma-debug.h
+++ b/include/linux/dma-debug.h
@@ -76,6 +76,8 @@ extern void debug_dma_sync_sg_for_device(struct device *dev,
                                          struct scatterlist *sg,
                                          int nelems, int direction);
 
+extern void debug_dma_dump_mappings(struct device *dev);
+
 #else /* CONFIG_DMA_API_DEBUG */
 
 static inline void dma_debug_init(u32 num_entries)
@@ -156,6 +158,10 @@ static inline void debug_dma_sync_sg_for_device(struct device *dev,
 {
 }
 
+static inline void debug_dma_dump_mappings(struct device *dev)
+{
+}
+
 #endif /* CONFIG_DMA_API_DEBUG */
 
 #endif /* __DMA_DEBUG_H */