Re: [Linaro-mm-sig] [PATCH 7/8] common: dma-mapping: change alloc/free_coherent method to more generic alloc/free_attrs

Hi.

On Mon, Jun 20, 2011 at 4:50 PM, Marek Szyprowski m.szyprowski@samsung.com wrote:

struct dma_map_ops {

• void* (*alloc_coherent)(struct device *dev, size_t size,
• dma_addr_t *dma_handle, gfp_t gfp);
• void (*free_coherent)(struct device *dev, size_t size,
• void *vaddr, dma_addr_t dma_handle);

• void* (*alloc)(struct device *dev, size_t size,
• dma_addr_t *dma_handle, gfp_t gfp,
• struct dma_attrs *attrs);
• void (*free)(struct device *dev, size_t size,
• void *vaddr, dma_addr_t dma_handle,
• struct dma_attrs *attrs);
• int (*mmap)(struct device *, struct vm_area_struct *,
• void *, dma_addr_t, size_t, struct dma_attrs *attrs);

dma_addr_t (*map_page)(struct device *dev, struct page *page,                               unsigned long offset, size_t size,                               enum dma_data_direction dir,

I still don't agree with your idea that change alloc_coherent() with alloc(). As I said before, we actually do not need dma_alloc_writecombine() anymore because it is not different from dma_alloc_coherent() in ARM. Most of other architectures do not have dma_alloc_writecombine(). If you want dma_alloc_coherent() to allocate user virtual address, I believe that it is also available with mmap() you introduced.

Regards, Cho KyongHo.