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

ARM: dma-mapping: remove offset parameter to prepare for generic dma_ops

Browse Source 
This patch removes the need for the offset parameter in dma bounce
functions. This is required to let dma-mapping framework on ARM
architecture to use common, generic dma_map_ops based dma-mapping
helpers.

Background and more detailed explaination:

dma_*_range_* functions are available from the early days of the dma
mapping api. They are the correct way of doing a partial syncs on the
buffer (usually used by the network device drivers). This patch changes
only the internal implementation of the dma bounce functions to let
them tunnel through dma_map_ops structure. The driver api stays
unchanged, so driver are obliged to call dma_*_range_* functions to
keep code clean and easy to understand.

The only drawback from this patch is reduced detection of the dma api
abuse. Let us consider the following code:

dma_addr = dma_map_single(dev, ptr, 64, DMA_TO_DEVICE);
dma_sync_single_range_for_cpu(dev, dma_addr+16, 0, 32, DMA_TO_DEVICE);

Without the patch such code fails, because dma bounce code is unable
to find the bounce buffer for the given dma_address. After the patch
the above sync call will be equivalent to:

dma_sync_single_range_for_cpu(dev, dma_addr, 16, 32, DMA_TO_DEVICE);

which succeeds.

I don't consider this as a real problem, because DMA API abuse should be
caught by debug_dma_* function family. This patch lets us to simplify
the internal low-level implementation without chaning the driver visible
API.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Tested-By: Subash Patel <subash.ramaswamy@linaro.org>
This commit is contained in:
Marek Szyprowski
2012-02-10 19:55:20 +01:00
parent 553ac78877
commit a227fb92a0
3 changed files with 45 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

67
arch/arm/include/asm/dma-mapping.h
View File

@@ -266,19 +266,17 @@ extern void __dma_unmap_page(struct device *, dma_addr_t, size_t,
/*
* Private functions
*/
int dmabounce_sync_for_cpu(struct device *, dma_addr_t, unsigned long,
size_t, enum dma_data_direction);
int dmabounce_sync_for_device(struct device *, dma_addr_t, unsigned long,
size_t, enum dma_data_direction);
int dmabounce_sync_for_cpu(struct device *, dma_addr_t, size_t, enum dma_data_direction);
int dmabounce_sync_for_device(struct device *, dma_addr_t, size_t, enum dma_data_direction);
#else
static inline int dmabounce_sync_for_cpu(struct device *d, dma_addr_t addr,
unsigned long offset, size_t size, enum dma_data_direction dir)
size_t size, enum dma_data_direction dir)
{
return 1;
}
static inline int dmabounce_sync_for_device(struct device *d, dma_addr_t addr,
unsigned long offset, size_t size, enum dma_data_direction dir)
size_t size, enum dma_data_direction dir)
{
return 1;
}
@@ -401,6 +399,33 @@ static inline void dma_unmap_page(struct device *dev, dma_addr_t handle,
__dma_unmap_page(dev, handle, size, dir);
}
static inline void dma_sync_single_for_cpu(struct device *dev,
dma_addr_t handle, size_t size, enum dma_data_direction dir)
{
BUG_ON(!valid_dma_direction(dir));
debug_dma_sync_single_for_cpu(dev, handle, size, dir);
if (!dmabounce_sync_for_cpu(dev, handle, size, dir))
return;
__dma_single_dev_to_cpu(dma_to_virt(dev, handle), size, dir);
}
static inline void dma_sync_single_for_device(struct device *dev,
dma_addr_t handle, size_t size, enum dma_data_direction dir)
{
BUG_ON(!valid_dma_direction(dir));
debug_dma_sync_single_for_device(dev, handle, size, dir);
if (!dmabounce_sync_for_device(dev, handle, size, dir))
return;
__dma_single_cpu_to_dev(dma_to_virt(dev, handle), size, dir);
}
/**
* dma_sync_single_range_for_cpu
* @dev: valid struct device pointer, or NULL for ISA and EISA-like devices
@@ -423,40 +448,14 @@ static inline void dma_sync_single_range_for_cpu(struct device *dev,
dma_addr_t handle, unsigned long offset, size_t size,
enum dma_data_direction dir)
{
BUG_ON(!valid_dma_direction(dir));
debug_dma_sync_single_for_cpu(dev, handle + offset, size, dir);
if (!dmabounce_sync_for_cpu(dev, handle, offset, size, dir))
return;
__dma_single_dev_to_cpu(dma_to_virt(dev, handle) + offset, size, dir);
dma_sync_single_for_cpu(dev, handle + offset, size, dir);
}
static inline void dma_sync_single_range_for_device(struct device *dev,
dma_addr_t handle, unsigned long offset, size_t size,
enum dma_data_direction dir)
{
BUG_ON(!valid_dma_direction(dir));
debug_dma_sync_single_for_device(dev, handle + offset, size, dir);
if (!dmabounce_sync_for_device(dev, handle, offset, size, dir))
return;
__dma_single_cpu_to_dev(dma_to_virt(dev, handle) + offset, size, dir);
}
static inline void dma_sync_single_for_cpu(struct device *dev,
dma_addr_t handle, size_t size, enum dma_data_direction dir)
{
dma_sync_single_range_for_cpu(dev, handle, 0, size, dir);
}
static inline void dma_sync_single_for_device(struct device *dev,
dma_addr_t handle, size_t size, enum dma_data_direction dir)
{
dma_sync_single_range_for_device(dev, handle, 0, size, dir);
dma_sync_single_for_device(dev, handle + offset, size, dir);
}
/*