Messages in this thread Patch in this message | | | Subject | Re: [PATCH 0/16] DMA-API debugging facility v2 | From | David Woodhouse <> | Date | Thu, 05 Feb 2009 22:52:32 +0000 |
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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.
I'd also like to make it answer the question 'should address X be mapped for device Y', but I'll get to that next.
Do we have a %pX format for printing dma_addr_t yet?
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/include/linux/dma-debug.h b/include/linux/dma-debug.h index 8a8aae4..5f4fc9f 100644 --- a/include/linux/dma-debug.h +++ b/include/linux/dma-debug.h @@ -75,6 +75,8 @@ 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) @@ -155,6 +157,10 @@ 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 */ diff --git a/lib/dma-debug.c b/lib/dma-debug.c index 469e5b9..127d108 100644 --- a/lib/dma-debug.c +++ b/lib/dma-debug.c @@ -191,6 +191,36 @@ static void hash_bucket_del(struct dma_debug_entry *entry) } /* + * 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. */
-- David Woodhouse Open Source Technology Centre David.Woodhouse@intel.com Intel Corporation
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