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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>
This commit is contained in:
David Woodhouse 2009-02-12 16:19:13 +01:00 committed by Joerg Roedel
parent a31fba5d68
commit ac26c18bd3
2 changed files with 36 additions and 0 deletions
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6
include/linux/dma-debug.h
View File

@ -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 */

30
lib/dma-debug.c
View File

@ -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.