xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

arm: dma-mapping: remove order parameter from arm_iommu_create_mapping()

Browse Source 
The 'order' parameter for IOMMU-aware dma-mapping implementation was
introduced mainly as a hack to reduce size of the bitmap used for
tracking IO virtual address space. Since now it is possible to dynamically
resize the bitmap, this hack is not needed and can be removed without any
impact on the client devices. This way the parameters for
arm_iommu_create_mapping() becomes much easier to understand. 'size'
parameter now means the maximum supported IO address space size.

The code will allocate (resize) bitmap in chunks, ensuring that a single
chunk is not larger than a single memory page to avoid unreliable
allocations of size larger than PAGE_SIZE in atomic context.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
This commit is contained in:
Marek Szyprowski
2014-02-25 13:01:09 +01:00
parent 4d852ef8c2
commit 68efd7d2fb
6 changed files with 25 additions and 33 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
arch/arm/include/asm/dma-iommu.h
View File

@@ -19,7 +19,6 @@ struct dma_iommu_mapping {
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;
spinlock_t lock;
@@ -27,8 +26,7 @@ struct dma_iommu_mapping {
};
struct dma_iommu_mapping *
arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size,
int order);
arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size);
void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping);