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

   1/*
   2 * Copyright (C) 2009-2010 PetaLogix
   3 * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
   4 *
   5 * Provide default implementations of the DMA mapping callbacks for
   6 * directly mapped busses.
   7 */
   8
   9#include <linux/device.h>
  10#include <linux/dma-mapping.h>
  11#include <linux/gfp.h>
  12#include <linux/dma-debug.h>
  13#include <linux/export.h>
  14#include <asm/bug.h>
  15
  16/*
  17 * Generic direct DMA implementation
  18 *
  19 * This implementation supports a per-device offset that can be applied if
  20 * the address at which memory is visible to devices is not 0. Platform code
  21 * can set archdata.dma_data to an unsigned long holding the offset. By
  22 * default the offset is PCI_DRAM_OFFSET.
  23 */
  24
  25static unsigned long get_dma_direct_offset(struct device *dev)
  26{
  27        if (likely(dev))
  28                return (unsigned long)dev->archdata.dma_data;
  29
  30        return PCI_DRAM_OFFSET; /* FIXME Not sure if is correct */
  31}
  32
  33#define NOT_COHERENT_CACHE
  34
  35static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
  36                                dma_addr_t *dma_handle, gfp_t flag)
  37{
  38#ifdef NOT_COHERENT_CACHE
  39        return consistent_alloc(flag, size, dma_handle);
  40#else
  41        void *ret;
  42        struct page *page;
  43        int node = dev_to_node(dev);
  44
  45        /* ignore region specifiers */
  46        flag  &= ~(__GFP_HIGHMEM);
  47
  48        page = alloc_pages_node(node, flag, get_order(size));
  49        if (page == NULL)
  50                return NULL;
  51        ret = page_address(page);
  52        memset(ret, 0, size);
  53        *dma_handle = virt_to_phys(ret) + get_dma_direct_offset(dev);
  54
  55        return ret;
  56#endif
  57}
  58
  59static void dma_direct_free_coherent(struct device *dev, size_t size,
  60                              void *vaddr, dma_addr_t dma_handle)
  61{
  62#ifdef NOT_COHERENT_CACHE
  63        consistent_free(size, vaddr);
  64#else
  65        free_pages((unsigned long)vaddr, get_order(size));
  66#endif
  67}
  68
  69static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
  70                             int nents, enum dma_data_direction direction,
  71                             struct dma_attrs *attrs)
  72{
  73        struct scatterlist *sg;
  74        int i;
  75
  76        /* FIXME this part of code is untested */
  77        for_each_sg(sgl, sg, nents, i) {
  78                sg->dma_address = sg_phys(sg) + get_dma_direct_offset(dev);
  79                __dma_sync(page_to_phys(sg_page(sg)) + sg->offset,
  80                                                        sg->length, direction);
  81        }
  82
  83        return nents;
  84}
  85
  86static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
  87                                int nents, enum dma_data_direction direction,
  88                                struct dma_attrs *attrs)
  89{
  90}
  91
  92static int dma_direct_dma_supported(struct device *dev, u64 mask)
  93{
  94        return 1;
  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 direction,
 102                                             struct dma_attrs *attrs)
 103{
 104        __dma_sync(page_to_phys(page) + offset, size, direction);
 105        return page_to_phys(page) + offset + get_dma_direct_offset(dev);
 106}
 107
 108static inline void dma_direct_unmap_page(struct device *dev,
 109                                         dma_addr_t dma_address,
 110                                         size_t size,
 111                                         enum dma_data_direction direction,
 112                                         struct dma_attrs *attrs)
 113{
 114/* There is not necessary to do cache cleanup
 115 *
 116 * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
 117 * dma_address is physical address
 118 */
 119        __dma_sync(dma_address, size, direction);
 120}
 121
 122static inline void
 123dma_direct_sync_single_for_cpu(struct device *dev,
 124                               dma_addr_t dma_handle, size_t size,
 125                               enum dma_data_direction direction)
 126{
 127        /*
 128         * It's pointless to flush the cache as the memory segment
 129         * is given to the CPU
 130         */
 131
 132        if (direction == DMA_FROM_DEVICE)
 133                __dma_sync(dma_handle, size, direction);
 134}
 135
 136static inline void
 137dma_direct_sync_single_for_device(struct device *dev,
 138                                  dma_addr_t dma_handle, size_t size,
 139                                  enum dma_data_direction direction)
 140{
 141        /*
 142         * It's pointless to invalidate the cache if the device isn't
 143         * supposed to write to the relevant region
 144         */
 145
 146        if (direction == DMA_TO_DEVICE)
 147                __dma_sync(dma_handle, size, direction);
 148}
 149
 150static inline void
 151dma_direct_sync_sg_for_cpu(struct device *dev,
 152                           struct scatterlist *sgl, int nents,
 153                           enum dma_data_direction direction)
 154{
 155        struct scatterlist *sg;
 156        int i;
 157
 158        /* FIXME this part of code is untested */
 159        if (direction == DMA_FROM_DEVICE)
 160                for_each_sg(sgl, sg, nents, i)
 161                        __dma_sync(sg->dma_address, sg->length, direction);
 162}
 163
 164static inline void
 165dma_direct_sync_sg_for_device(struct device *dev,
 166                              struct scatterlist *sgl, int nents,
 167                              enum dma_data_direction direction)
 168{
 169        struct scatterlist *sg;
 170        int i;
 171
 172        /* FIXME this part of code is untested */
 173        if (direction == DMA_TO_DEVICE)
 174                for_each_sg(sgl, sg, nents, i)
 175                        __dma_sync(sg->dma_address, sg->length, direction);
 176}
 177
 178struct dma_map_ops dma_direct_ops = {
 179        .alloc_coherent = dma_direct_alloc_coherent,
 180        .free_coherent  = dma_direct_free_coherent,
 181        .map_sg         = dma_direct_map_sg,
 182        .unmap_sg       = dma_direct_unmap_sg,
 183        .dma_supported  = dma_direct_dma_supported,
 184        .map_page       = dma_direct_map_page,
 185        .unmap_page     = dma_direct_unmap_page,
 186        .sync_single_for_cpu            = dma_direct_sync_single_for_cpu,
 187        .sync_single_for_device         = dma_direct_sync_single_for_device,
 188        .sync_sg_for_cpu                = dma_direct_sync_sg_for_cpu,
 189        .sync_sg_for_device             = dma_direct_sync_sg_for_device,
 190};
 191EXPORT_SYMBOL(dma_direct_ops);
 192
 193/* Number of entries preallocated for DMA-API debugging */
 194#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 195
 196static int __init dma_init(void)
 197{
 198       dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
 199
 200       return 0;
 201}
 202fs_initcall(dma_init);
 203