arm: dma-mapping: Add support to extend DMA IOMMU mappings

Instead of using just one bitmap to keep track of IO virtual addresses
(handed out for IOMMU use) introduce an array of bitmaps. This allows
us to extend existing mappings when running out of iova space in the
initial mapping etc.

If there is not enough space in the mapping to service an IO virtual
address allocation request, __alloc_iova() tries to extend the mapping
-- by allocating another bitmap -- and makes another allocation
attempt using the freshly allocated bitmap.

This allows arm iommu drivers to start with a decent initial size when
an dma_iommu_mapping is created and still to avoid running out of IO
virtual addresses for the mapping.

Signed-off-by: Andreas Herrmann <andreas.herrmann@calxeda.com>
[mszyprow: removed extensions parameter to arm_iommu_create_mapping()
 function, which will be modified in the next patch anyway, also some
 debug messages about extending bitmap]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/arch/arm/include/asm/dma-iommu.h b/arch/arm/include/asm/dma-iommu.h
index a8c56acc8c98..686797cf5618 100644
--- a/arch/arm/include/asm/dma-iommu.h
+++ b/arch/arm/include/asm/dma-iommu.h
@@ -13,8 +13,12 @@ struct dma_iommu_mapping {
 	/* iommu specific data */
 	struct iommu_domain	*domain;
 
-	void			*bitmap;
-	size_t			bits;
+	unsigned long		**bitmaps;	/* array of bitmaps */
+	unsigned int		nr_bitmaps;	/* nr of elements in array */
+	unsigned int		extensions;
+	size_t			bitmap_size;	/* size of a single bitmap */
+	size_t			bits;		/* per bitmap */
+	unsigned int		size;		/* per bitmap */
 	unsigned int		order;
 	dma_addr_t		base;