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

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>

1 files changed, 33 insertions, 34 deletions

diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index 6a838da03c5..eeddbe201e2 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -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);
 }
 
 /*