diff options
| author | Marek Szyprowski <m.szyprowski@samsung.com> | 2012-02-10 19:55:20 +0100 |
|---|---|---|
| committer | Marek Szyprowski <m.szyprowski@samsung.com> | 2012-05-21 15:06:13 +0200 |
| commit | a227fb92a0f5f0dd8282719386e9b3a29f0d16b2 (patch) | |
| tree | b990f647dcb38e17a4eef63b14f3358e6698e5c3 /arch/arm/common | |
| parent | 553ac78877242b6d8b591323731df304140d0f99 (diff) | |
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>
Diffstat (limited to 'arch/arm/common')
| -rw-r--r-- | arch/arm/common/dmabounce.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c index 210ad1bef7e5..32e9cc6ca7d9 100644 --- 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", |