LXR linux/arch/m68k/kernel/dma

   1/*
   2 * Dynamic DMA mapping support.
   3 *
   4 * We never have any address translations to worry about, so this
   5 * is just alloc/free.
   6 */
   7
   8#include <linux/types.h>
   9#include <linux/gfp.h>
  10#include <linux/mm.h>
  11#include <linux/device.h>
  12#include <linux/dma-mapping.h>
  13#include <linux/export.h>
  14#include <asm/cacheflush.h>
  15
  16void *dma_alloc_coherent(struct device *dev, size_t size,
  17                           dma_addr_t *dma_handle, gfp_t gfp)
  18{
  19        void *ret;
  20        /* ignore region specifiers */
  21        gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
  22
  23        if (dev == NULL || (*dev->dma_mask < 0xffffffff))
  24                gfp |= GFP_DMA;
  25        ret = (void *)__get_free_pages(gfp, get_order(size));
  26
  27        if (ret != NULL) {
  28                memset(ret, 0, size);
  29                *dma_handle = virt_to_phys(ret);
  30        }
  31        return ret;
  32}
  33
  34void dma_free_coherent(struct device *dev, size_t size,
  35                         void *vaddr, dma_addr_t dma_handle)
  36{
  37        free_pages((unsigned long)vaddr, get_order(size));
  38}
  39
  40void dma_sync_single_for_device(struct device *dev, dma_addr_t handle,
  41                                size_t size, enum dma_data_direction dir)
  42{
  43        switch (dir) {
  44        case DMA_TO_DEVICE:
  45                flush_dcache_range(handle, size);
  46                break;
  47        case DMA_FROM_DEVICE:
  48                /* Should be clear already */
  49                break;
  50        default:
  51                if (printk_ratelimit())
  52                        printk("dma_sync_single_for_device: unsupported dir %u\n", dir);
  53                break;
  54        }
  55}
  56
  57EXPORT_SYMBOL(dma_sync_single_for_device);
  58dma_addr_t dma_map_single(struct device *dev, void *addr, size_t size,
  59                          enum dma_data_direction dir)
  60{
  61        dma_addr_t handle = virt_to_phys(addr);
  62        flush_dcache_range(handle, size);
  63        return handle;
  64}
  65EXPORT_SYMBOL(dma_map_single);
  66
  67dma_addr_t dma_map_page(struct device *dev, struct page *page,
  68                        unsigned long offset, size_t size,
  69                        enum dma_data_direction dir)
  70{
  71        dma_addr_t handle = page_to_phys(page) + offset;
  72        dma_sync_single_for_device(dev, handle, size, dir);
  73        return handle;
  74}
  75EXPORT_SYMBOL(dma_map_page);
  76