drivers/infiniband/hw/ipath/ipath_dma.c

   1 /*
   2  * Copyright (c) 2006 QLogic, Corporation. All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and/or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  */
  32
  33 #include <rdma/ib_verbs.h>
  34
  35 #include "ipath_verbs.h"
  36
  37 #define BAD_DMA_ADDRESS ((u64) 0)
  38
  39 /*
  40  * The following functions implement driver specific replacements
  41  * for the ib_dma_*() functions.
  42  *
  43  * These functions return kernel virtual addresses instead of
  44  * device bus addresses since the driver uses the CPU to copy
  45  * data instead of using hardware DMA.
  46  */
  47
  48 static int ipath_mapping_error(struct ib_device *dev, u64 dma_addr)
  49 {
  50         return dma_addr == BAD_DMA_ADDRESS;
  51 }
  52
  53 static u64 ipath_dma_map_single(struct ib_device *dev,
  54                                 void *cpu_addr, size_t size,
  55                                 enum dma_data_direction direction)
  56 {
  57         BUG_ON(!valid_dma_direction(direction));
  58         return (u64) cpu_addr;
  59 }
  60
  61 static void ipath_dma_unmap_single(struct ib_device *dev,
  62                                    u64 addr, size_t size,
  63                                    enum dma_data_direction direction)
  64 {
  65         BUG_ON(!valid_dma_direction(direction));
  66 }
  67
  68 static u64 ipath_dma_map_page(struct ib_device *dev,
  69                               struct page *page,
  70                               unsigned long offset,
  71                               size_t size,
  72                               enum dma_data_direction direction)
  73 {
  74         u64 addr;
  75
  76         BUG_ON(!valid_dma_direction(direction));
  77
  78         if (offset + size > PAGE_SIZE) {
  79                 addr = BAD_DMA_ADDRESS;
  80                 goto done;
  81         }
  82
  83         addr = (u64) page_address(page);
  84         if (addr)
  85                 addr += offset;
  86         /* TODO: handle highmem pages */
  87
  88 done:
  89         return addr;
  90 }
  91
  92 static void ipath_dma_unmap_page(struct ib_device *dev,
  93                                  u64 addr, size_t size,
  94                                  enum dma_data_direction direction)
  95 {
  96         BUG_ON(!valid_dma_direction(direction));
  97 }
  98
  99 int ipath_map_sg(struct ib_device *dev, struct scatterlist *sg, int nents,
 100                  enum dma_data_direction direction)
 101 {
 102         u64 addr;
 103         int i;
 104         int ret = nents;
 105
 106         BUG_ON(!valid_dma_direction(direction));
 107
 108         for (i = 0; i < nents; i++) {
 109                 addr = (u64) page_address(sg[i].page);
 110                 /* TODO: handle highmem pages */
 111                 if (!addr) {
 112                         ret = 0;
 113                         break;
 114                 }
 115         }
 116         return ret;
 117 }
 118
 119 static void ipath_unmap_sg(struct ib_device *dev,
 120                            struct scatterlist *sg, int nents,
 121                            enum dma_data_direction direction)
 122 {
 123         BUG_ON(!valid_dma_direction(direction));
 124 }
 125
 126 static u64 ipath_sg_dma_address(struct ib_device *dev, struct scatterlist *sg)
 127 {
 128         u64 addr = (u64) page_address(sg->page);
 129
 130         if (addr)
 131                 addr += sg->offset;
 132         return addr;
 133 }
 134
 135 static unsigned int ipath_sg_dma_len(struct ib_device *dev,
 136                                      struct scatterlist *sg)
 137 {
 138         return sg->length;
 139 }
 140
 141 static void ipath_sync_single_for_cpu(struct ib_device *dev,
 142                                       u64 addr,
 143                                       size_t size,
 144                                       enum dma_data_direction dir)
 145 {
 146 }
 147
 148 static void ipath_sync_single_for_device(struct ib_device *dev,
 149                                          u64 addr,
 150                                          size_t size,
 151                                          enum dma_data_direction dir)
 152 {
 153 }
 154
 155 static void *ipath_dma_alloc_coherent(struct ib_device *dev, size_t size,
 156                                       u64 *dma_handle, gfp_t flag)
 157 {
 158         struct page *p;
 159         void *addr = NULL;
 160
 161         p = alloc_pages(flag, get_order(size));
 162         if (p)
 163                 addr = page_address(p);
 164         if (dma_handle)
 165                 *dma_handle = (u64) addr;
 166         return addr;
 167 }
 168
 169 static void ipath_dma_free_coherent(struct ib_device *dev, size_t size,
 170                                     void *cpu_addr, dma_addr_t dma_handle)
 171 {
 172         free_pages((unsigned long) cpu_addr, get_order(size));
 173 }
 174
 175 struct ib_dma_mapping_ops ipath_dma_mapping_ops = {
 176         ipath_mapping_error,
 177         ipath_dma_map_single,
 178         ipath_dma_unmap_single,
 179         ipath_dma_map_page,
 180         ipath_dma_unmap_page,
 181         ipath_map_sg,
 182         ipath_unmap_sg,
 183         ipath_sg_dma_address,
 184         ipath_sg_dma_len,
 185         ipath_sync_single_for_cpu,
 186         ipath_sync_single_for_device,
 187         ipath_dma_alloc_coherent,
 188         ipath_dma_free_coherent
 189 };