linux-toradex.git/arch/arm/common/dmabounce.c, branch v3.12.49

ARM: dma-mapping: add support for dma_get_sgtable()

2012-07-30T10:25:47+00:00

This patch adds support for dma_get_sgtable() function which is required
to let drivers to share the buffers allocated by DMA-mapping subsystem.

Generic implementation based on virt_to_page() is not suitable for ARM
dma-mapping subsystem.

Signed-off-by: Marek Szyprowski 
Reviewed-by: Kyungmin Park

ARM: dma-mapping: fix debug messages in dmabounce code

2012-06-13T12:25:16+00:00

This patch fixes the usage of uninitialized variables in dmabounce code
intoduced by commit a227fb92 ('ARM: dma-mapping: remove offset parameter
to prepare for generic dma_ops'):
arch/arm/common/dmabounce.c: In function ‘dmabounce_sync_for_device’:
arch/arm/common/dmabounce.c:409: warning: ‘off’ may be used uninitialized in this function
arch/arm/common/dmabounce.c:407: note: ‘off’ was declared here
arch/arm/common/dmabounce.c: In function ‘dmabounce_sync_for_cpu’:
arch/arm/common/dmabounce.c:369: warning: ‘off’ may be used uninitialized in this function
arch/arm/common/dmabounce.c:367: note: ‘off’ was declared here

Signed-off-by: Marek Szyprowski

ARM: dma-mapping: use alloc, mmap, free from dma_ops

2012-05-21T13:06:22+00:00

This patch converts dma_alloc/free/mmap_{coherent,writecombine}
functions to use generic alloc/free/mmap methods from dma_map_ops
structure. A new DMA_ATTR_WRITE_COMBINE DMA attribute have been
introduced to implement writecombine methods.

Signed-off-by: Marek Szyprowski 
Acked-by: Kyungmin Park 
Acked-by: Arnd Bergmann 
Tested-By: Subash Patel

ARM: dma-mapping: move all dma bounce code to separate dma ops structure

2012-05-21T13:06:18+00:00

This patch removes dma bounce hooks from the common dma mapping
implementation on ARM architecture and creates a separate set of
dma_map_ops for dma bounce devices.

Signed-off-by: Marek Szyprowski 
Acked-by: Kyungmin Park 
Tested-By: Subash Patel

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

2012-05-21T13:06:13+00:00

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 
Acked-by: Kyungmin Park 
Tested-By: Subash Patel

ARM: dma-mapping: introduce DMA_ERROR_CODE constant

2012-05-21T13:06:12+00:00

Replace all uses of ~0 with DMA_ERROR_CODE, what should make the code
easier to read.

Signed-off-by: Marek Szyprowski 
Acked-by: Kyungmin Park 
Tested-By: Subash Patel

ARM: dmabounce: get rid of dma_needs_bounce global function

2011-07-04T07:39:55+00:00

Pass the device type specific needs_bounce function in at dmabounce
register time, avoiding the need for a platform specific global
function to do this.

Signed-off-by: Russell King

ARM: dmabounce: correct unmap_single dev_dbg

2011-07-03T22:56:17+00:00

DMA addresses should not be casted to void * for printing.  Fix
that to be consistent with the rest of the file.

Signed-off-by: Russell King

ARM: dmabounce: check pointer against NULL not 0

2011-07-03T22:54:34+00:00

Pointers should be checked against NULL rather than 0, otherwise we
get sparse warnings.

Signed-off-by: Russell King

ARM: dmabounce: remove useless pr_err

2011-07-03T22:53:13+00:00

We already check that dev != NULL, so this won't be reached.

Signed-off-by: Russell King