75 строки
1.8 KiB
C
75 строки
1.8 KiB
C
/*
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* Dynamic DMA mapping support.
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*
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* We never have any address translations to worry about, so this
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* is just alloc/free.
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*/
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#include <linux/types.h>
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#include <linux/gfp.h>
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#include <linux/mm.h>
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#include <linux/device.h>
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#include <linux/dma-mapping.h>
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#include <asm/cacheflush.h>
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void *dma_alloc_coherent(struct device *dev, size_t size,
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dma_addr_t *dma_handle, gfp_t gfp)
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{
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void *ret;
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/* ignore region specifiers */
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gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
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if (dev == NULL || (*dev->dma_mask < 0xffffffff))
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gfp |= GFP_DMA;
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ret = (void *)__get_free_pages(gfp, get_order(size));
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if (ret != NULL) {
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memset(ret, 0, size);
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*dma_handle = virt_to_phys(ret);
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}
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return ret;
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}
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void dma_free_coherent(struct device *dev, size_t size,
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void *vaddr, dma_addr_t dma_handle)
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{
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free_pages((unsigned long)vaddr, get_order(size));
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}
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void dma_sync_single_for_device(struct device *dev, dma_addr_t handle,
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size_t size, enum dma_data_direction dir)
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{
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switch (dir) {
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case DMA_TO_DEVICE:
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flush_dcache_range(handle, size);
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break;
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case DMA_FROM_DEVICE:
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/* Should be clear already */
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break;
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default:
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if (printk_ratelimit())
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printk("dma_sync_single_for_device: unsupported dir %u\n", dir);
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break;
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}
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}
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EXPORT_SYMBOL(dma_sync_single_for_device);
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dma_addr_t dma_map_single(struct device *dev, void *addr, size_t size,
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enum dma_data_direction dir)
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{
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dma_addr_t handle = virt_to_phys(addr);
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flush_dcache_range(handle, size);
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return handle;
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}
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EXPORT_SYMBOL(dma_map_single);
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dma_addr_t dma_map_page(struct device *dev, struct page *page,
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unsigned long offset, size_t size,
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enum dma_data_direction dir)
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{
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dma_addr_t handle = page_to_phys(page) + offset;
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dma_sync_single_for_device(dev, handle, size, dir);
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return handle;
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}
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EXPORT_SYMBOL(dma_map_page);
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