Commit ac26c18b authored by David Woodhouse's avatar David Woodhouse Committed by Joerg Roedel
Browse files

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: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent a31fba5d

include/linux/dma-debug.h

+6 −0
Original line number Diff line number Diff line
@@ -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 */

lib/dma-debug.c

+30 −0
Original line number Diff line number Diff line
@@ -193,6 +193,36 @@ static void hash_bucket_del(struct dma_debug_entry *entry) 
	list_del(&entry->list);

}



/*

 * Dump mapping entries for debugging purposes

 */

void debug_dma_dump_mappings(struct device *dev)

{

	int idx;



	for (idx = 0; idx < HASH_SIZE; idx++) {

		struct hash_bucket *bucket = &dma_entry_hash[idx];

		struct dma_debug_entry *entry;

		unsigned long flags;



		spin_lock_irqsave(&bucket->lock, flags);



		list_for_each_entry(entry, &bucket->list, list) {

			if (!dev || dev == entry->dev) {

				dev_info(entry->dev,

					 "%s idx %d P=%Lx D=%Lx L=%Lx %s\n",

					 type2name[entry->type], idx,

					 (unsigned long long)entry->paddr,

					 entry->dev_addr, entry->size,

					 dir2name[entry->direction]);

			}

		}



		spin_unlock_irqrestore(&bucket->lock, flags);

	}

}

EXPORT_SYMBOL(debug_dma_dump_mappings);



/*

 * Wrapper function for adding an entry to the hash.

 * This function takes care of locking itself.

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