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

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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>
This commit is contained in:
Andreas Herrmann
2014-02-25 13:09:53 +01:00
committed by Marek Szyprowski
parent cfbf8d4857
commit 4d852ef8c2
2 changed files with 110 additions and 21 deletions
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8
arch/arm/include/asm/dma-iommu.h
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@@ -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;