LXR linux/arch/powerpc/kernel/dma.c

   1/*
   2 * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
   3 *
   4 * Provide default implementations of the DMA mapping callbacks for
   5 * directly mapped busses.
   6 */
   7
   8#include <linux/device.h>
   9#include <linux/dma-mapping.h>
  10#include <linux/dma-debug.h>
  11#include <linux/lmb.h>
  12#include <asm/bug.h>
  13#include <asm/abs_addr.h>
  14
  15/*
  16 * Generic direct DMA implementation
  17 *
  18 * This implementation supports a per-device offset that can be applied if
  19 * the address at which memory is visible to devices is not 0. Platform code
  20 * can set archdata.dma_data to an unsigned long holding the offset. By
  21 * default the offset is PCI_DRAM_OFFSET.
  22 */
  23
  24
  25void *dma_direct_alloc_coherent(struct device *dev, size_t size,
  26                                dma_addr_t *dma_handle, gfp_t flag)
  27{
  28        void *ret;
  29#ifdef CONFIG_NOT_COHERENT_CACHE
  30        ret = __dma_alloc_coherent(dev, size, dma_handle, flag);
  31        if (ret == NULL)
  32                return NULL;
  33        *dma_handle += get_dma_offset(dev);
  34        return ret;
  35#else
  36        struct page *page;
  37        int node = dev_to_node(dev);
  38
  39        /* ignore region specifiers */
  40        flag  &= ~(__GFP_HIGHMEM);
  41
  42        page = alloc_pages_node(node, flag, get_order(size));
  43        if (page == NULL)
  44                return NULL;
  45        ret = page_address(page);
  46        memset(ret, 0, size);
  47        *dma_handle = virt_to_abs(ret) + get_dma_offset(dev);
  48
  49        return ret;
  50#endif
  51}
  52
  53void dma_direct_free_coherent(struct device *dev, size_t size,
  54                              void *vaddr, dma_addr_t dma_handle)
  55{
  56#ifdef CONFIG_NOT_COHERENT_CACHE
  57        __dma_free_coherent(size, vaddr);
  58#else
  59        free_pages((unsigned long)vaddr, get_order(size));
  60#endif
  61}
  62
  63static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
  64                             int nents, enum dma_data_direction direction,
  65                             struct dma_attrs *attrs)
  66{
  67        struct scatterlist *sg;
  68        int i;
  69
  70        for_each_sg(sgl, sg, nents, i) {
  71                sg->dma_address = sg_phys(sg) + get_dma_offset(dev);
  72                sg->dma_length = sg->length;
  73                __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
  74        }
  75
  76        return nents;
  77}
  78
  79static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
  80                                int nents, enum dma_data_direction direction,
  81                                struct dma_attrs *attrs)
  82{
  83}
  84
  85static int dma_direct_dma_supported(struct device *dev, u64 mask)
  86{
  87#ifdef CONFIG_PPC64
  88        /* Could be improved so platforms can set the limit in case
  89         * they have limited DMA windows
  90         */
  91        return mask >= (lmb_end_of_DRAM() - 1);
  92#else
  93        return 1;
  94#endif
  95}
  96
  97static inline dma_addr_t dma_direct_map_page(struct device *dev,
  98                                             struct page *page,
  99                                             unsigned long offset,
 100                                             size_t size,
 101                                             enum dma_data_direction dir,
 102                                             struct dma_attrs *attrs)
 103{
 104        BUG_ON(dir == DMA_NONE);
 105        __dma_sync_page(page, offset, size, dir);
 106        return page_to_phys(page) + offset + get_dma_offset(dev);
 107}
 108
 109static inline void dma_direct_unmap_page(struct device *dev,
 110                                         dma_addr_t dma_address,
 111                                         size_t size,
 112                                         enum dma_data_direction direction,
 113                                         struct dma_attrs *attrs)
 114{
 115}
 116
 117#ifdef CONFIG_NOT_COHERENT_CACHE
 118static inline void dma_direct_sync_sg(struct device *dev,
 119                struct scatterlist *sgl, int nents,
 120                enum dma_data_direction direction)
 121{
 122        struct scatterlist *sg;
 123        int i;
 124
 125        for_each_sg(sgl, sg, nents, i)
 126                __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
 127}
 128
 129static inline void dma_direct_sync_single_range(struct device *dev,
 130                dma_addr_t dma_handle, unsigned long offset, size_t size,
 131                enum dma_data_direction direction)
 132{
 133        __dma_sync(bus_to_virt(dma_handle+offset), size, direction);
 134}
 135#endif
 136
 137struct dma_map_ops dma_direct_ops = {
 138        .alloc_coherent = dma_direct_alloc_coherent,
 139        .free_coherent  = dma_direct_free_coherent,
 140        .map_sg         = dma_direct_map_sg,
 141        .unmap_sg       = dma_direct_unmap_sg,
 142        .dma_supported  = dma_direct_dma_supported,
 143        .map_page       = dma_direct_map_page,
 144        .unmap_page     = dma_direct_unmap_page,
 145#ifdef CONFIG_NOT_COHERENT_CACHE
 146        .sync_single_range_for_cpu      = dma_direct_sync_single_range,
 147        .sync_single_range_for_device   = dma_direct_sync_single_range,
 148        .sync_sg_for_cpu                = dma_direct_sync_sg,
 149        .sync_sg_for_device             = dma_direct_sync_sg,
 150#endif
 151};
 152EXPORT_SYMBOL(dma_direct_ops);
 153
 154#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 155
 156static int __init dma_init(void)
 157{
 158       dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 159
 160       return 0;
 161}
 162fs_initcall(dma_init);
 163