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- /*
- * Copyright (C) 2009-2010 PetaLogix
- * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
- *
- * Provide default implementations of the DMA mapping callbacks for
- * directly mapped busses.
- */
- #include <linux/device.h>
- #include <linux/dma-mapping.h>
- #include <linux/gfp.h>
- #include <linux/dma-debug.h>
- #include <linux/export.h>
- #include <linux/bug.h>
- #define NOT_COHERENT_CACHE
- static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
- dma_addr_t *dma_handle, gfp_t flag,
- unsigned long attrs)
- {
- #ifdef NOT_COHERENT_CACHE
- return consistent_alloc(flag, size, dma_handle);
- #else
- void *ret;
- struct page *page;
- int node = dev_to_node(dev);
- /* ignore region specifiers */
- flag &= ~(__GFP_HIGHMEM);
- page = alloc_pages_node(node, flag, get_order(size));
- if (page == NULL)
- return NULL;
- ret = page_address(page);
- memset(ret, 0, size);
- *dma_handle = virt_to_phys(ret);
- return ret;
- #endif
- }
- static void dma_direct_free_coherent(struct device *dev, size_t size,
- void *vaddr, dma_addr_t dma_handle,
- unsigned long attrs)
- {
- #ifdef NOT_COHERENT_CACHE
- consistent_free(size, vaddr);
- #else
- free_pages((unsigned long)vaddr, get_order(size));
- #endif
- }
- static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
- int nents, enum dma_data_direction direction,
- unsigned long attrs)
- {
- struct scatterlist *sg;
- int i;
- /* FIXME this part of code is untested */
- for_each_sg(sgl, sg, nents, i) {
- sg->dma_address = sg_phys(sg);
- __dma_sync(page_to_phys(sg_page(sg)) + sg->offset,
- sg->length, direction);
- }
- return nents;
- }
- static int dma_direct_dma_supported(struct device *dev, u64 mask)
- {
- return 1;
- }
- static inline dma_addr_t dma_direct_map_page(struct device *dev,
- struct page *page,
- unsigned long offset,
- size_t size,
- enum dma_data_direction direction,
- unsigned long attrs)
- {
- __dma_sync(page_to_phys(page) + offset, size, direction);
- return page_to_phys(page) + offset;
- }
- static inline void dma_direct_unmap_page(struct device *dev,
- dma_addr_t dma_address,
- size_t size,
- enum dma_data_direction direction,
- unsigned long attrs)
- {
- /* There is not necessary to do cache cleanup
- *
- * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
- * dma_address is physical address
- */
- __dma_sync(dma_address, size, direction);
- }
- static inline void
- dma_direct_sync_single_for_cpu(struct device *dev,
- dma_addr_t dma_handle, size_t size,
- enum dma_data_direction direction)
- {
- /*
- * It's pointless to flush the cache as the memory segment
- * is given to the CPU
- */
- if (direction == DMA_FROM_DEVICE)
- __dma_sync(dma_handle, size, direction);
- }
- static inline void
- dma_direct_sync_single_for_device(struct device *dev,
- dma_addr_t dma_handle, size_t size,
- enum dma_data_direction direction)
- {
- /*
- * It's pointless to invalidate the cache if the device isn't
- * supposed to write to the relevant region
- */
- if (direction == DMA_TO_DEVICE)
- __dma_sync(dma_handle, size, direction);
- }
- static inline void
- dma_direct_sync_sg_for_cpu(struct device *dev,
- struct scatterlist *sgl, int nents,
- enum dma_data_direction direction)
- {
- struct scatterlist *sg;
- int i;
- /* FIXME this part of code is untested */
- if (direction == DMA_FROM_DEVICE)
- for_each_sg(sgl, sg, nents, i)
- __dma_sync(sg->dma_address, sg->length, direction);
- }
- static inline void
- dma_direct_sync_sg_for_device(struct device *dev,
- struct scatterlist *sgl, int nents,
- enum dma_data_direction direction)
- {
- struct scatterlist *sg;
- int i;
- /* FIXME this part of code is untested */
- if (direction == DMA_TO_DEVICE)
- for_each_sg(sgl, sg, nents, i)
- __dma_sync(sg->dma_address, sg->length, direction);
- }
- static
- int dma_direct_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
- void *cpu_addr, dma_addr_t handle, size_t size,
- unsigned long attrs)
- {
- #ifdef CONFIG_MMU
- unsigned long user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
- unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
- unsigned long off = vma->vm_pgoff;
- unsigned long pfn;
- if (off >= count || user_count > (count - off))
- return -ENXIO;
- #ifdef NOT_COHERENT_CACHE
- vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
- pfn = consistent_virt_to_pfn(cpu_addr);
- #else
- pfn = virt_to_pfn(cpu_addr);
- #endif
- return remap_pfn_range(vma, vma->vm_start, pfn + off,
- vma->vm_end - vma->vm_start, vma->vm_page_prot);
- #else
- return -ENXIO;
- #endif
- }
- struct dma_map_ops dma_direct_ops = {
- .alloc = dma_direct_alloc_coherent,
- .free = dma_direct_free_coherent,
- .mmap = dma_direct_mmap_coherent,
- .map_sg = dma_direct_map_sg,
- .dma_supported = dma_direct_dma_supported,
- .map_page = dma_direct_map_page,
- .unmap_page = dma_direct_unmap_page,
- .sync_single_for_cpu = dma_direct_sync_single_for_cpu,
- .sync_single_for_device = dma_direct_sync_single_for_device,
- .sync_sg_for_cpu = dma_direct_sync_sg_for_cpu,
- .sync_sg_for_device = dma_direct_sync_sg_for_device,
- };
- EXPORT_SYMBOL(dma_direct_ops);
- /* Number of entries preallocated for DMA-API debugging */
- #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
- static int __init dma_init(void)
- {
- dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
- return 0;
- }
- fs_initcall(dma_init);
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