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>

diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c
index 210ad1bef7e51aaf02dc79acb30cd7b48cf16e1d..32e9cc6ca7d91d903df09fb1daba0997c77b440e 100644 (file)
--- a/arch/arm/common/dmabounce.c
+++ b/arch/arm/common/dmabounce.c
@@ -173,7 +173,8 @@ find_safe_buffer(struct dmabounce_device_info *device_info, dma_addr_t safe_dma_
        read_lock_irqsave(&device_info->lock, flags);
 
        list_for_each_entry(b, &device_info->safe_buffers, node)
-               if (b->safe_dma_addr == safe_dma_addr) {
+               if (b->safe_dma_addr <= safe_dma_addr &&
+                   b->safe_dma_addr + b->size > safe_dma_addr) {
                        rb = b;
                        break;
                }
@@ -362,9 +363,10 @@ void __dma_unmap_page(struct device *dev, dma_addr_t dma_addr, size_t size,
 EXPORT_SYMBOL(__dma_unmap_page);
 
 int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
-               unsigned long off, size_t sz, enum dma_data_direction dir)
+               size_t sz, enum dma_data_direction dir)
 {
        struct safe_buffer *buf;
+       unsigned long off;
 
        dev_dbg(dev, "%s(dma=%#x,off=%#lx,sz=%zx,dir=%x)\n",
                __func__, addr, off, sz, dir);
@@ -373,6 +375,8 @@ int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
        if (!buf)
                return 1;
 
+       off = addr - buf->safe_dma_addr;
+
        BUG_ON(buf->direction != dir);
 
        dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",
@@ -391,9 +395,10 @@ int dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr,
 EXPORT_SYMBOL(dmabounce_sync_for_cpu);
 
 int dmabounce_sync_for_device(struct device *dev, dma_addr_t addr,
-               unsigned long off, size_t sz, enum dma_data_direction dir)
+               size_t sz, enum dma_data_direction dir)
 {
        struct safe_buffer *buf;
+       unsigned long off;
 
        dev_dbg(dev, "%s(dma=%#x,off=%#lx,sz=%zx,dir=%x)\n",
                __func__, addr, off, sz, dir);
@@ -402,6 +407,8 @@ int dmabounce_sync_for_device(struct device *dev, dma_addr_t addr,
        if (!buf)
                return 1;
 
+       off = addr - buf->safe_dma_addr;
+
        BUG_ON(buf->direction != dir);
 
        dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n",

diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index 6a838da03c5b05ab870808d7eb7e5351f9bb5c06..eeddbe201e248ac51bc5148dade1134facd23c5d 100644 (file)
--- 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);
 }
 
 /*

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index e4ac5fc86b0a2306b58c2236aaa242ead38ae4fe..a16993a5b7eb1fb62977c66be1150dfaf81e91d5 100644 (file)
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -660,7 +660,7 @@ void dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
        int i;
 
        for_each_sg(sg, s, nents, i) {
-               if (!dmabounce_sync_for_cpu(dev, sg_dma_address(s), 0,
+               if (!dmabounce_sync_for_cpu(dev, sg_dma_address(s),
                                            sg_dma_len(s), dir))
                        continue;
 
@@ -686,7 +686,7 @@ void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
        int i;
 
        for_each_sg(sg, s, nents, i) {
-               if (!dmabounce_sync_for_device(dev, sg_dma_address(s), 0,
+               if (!dmabounce_sync_for_device(dev, sg_dma_address(s),
                                        sg_dma_len(s), dir))
                        continue;