kernel/drivers/infiniband/hw/qib/qib_dma.c

   1 /*
   2  * Copyright (c) 2006, 2009, 2010 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 #include <linux/types.h>
  33 #include <linux/scatterlist.h>
  34
  35 #include "qib_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 qib_mapping_error(struct ib_device *dev, u64 dma_addr)
  49 {
  50         return dma_addr == BAD_DMA_ADDRESS;
  51 }
  52
  53 static u64 qib_dma_map_single(struct ib_device *dev, void *cpu_addr,
  54                               size_t size, enum dma_data_direction direction)
  55 {
  56         BUG_ON(!valid_dma_direction(direction));
  57         return (u64) cpu_addr;
  58 }
  59
  60 static void qib_dma_unmap_single(struct ib_device *dev, u64 addr, size_t size,
  61                                  enum dma_data_direction direction)
  62 {
  63         BUG_ON(!valid_dma_direction(direction));
  64 }
  65
  66 static u64 qib_dma_map_page(struct ib_device *dev, struct page *page,
  67                             unsigned long offset, size_t size,
  68                             enum dma_data_direction direction)
  69 {
  70         u64 addr;
  71
  72         BUG_ON(!valid_dma_direction(direction));
  73
  74         if (offset + size > PAGE_SIZE) {
  75                 addr = BAD_DMA_ADDRESS;
  76                 goto done;
  77         }
  78
  79         addr = (u64) page_address(page);
  80         if (addr)
  81                 addr += offset;
  82         /* TODO: handle highmem pages */
  83
  84 done:
  85         return addr;
  86 }
  87
  88 static void qib_dma_unmap_page(struct ib_device *dev, u64 addr, size_t size,
  89                                enum dma_data_direction direction)
  90 {
  91         BUG_ON(!valid_dma_direction(direction));
  92 }
  93
  94 static int qib_map_sg(struct ib_device *dev, struct scatterlist *sgl,
  95                       int nents, enum dma_data_direction direction)
  96 {
  97         struct scatterlist *sg;
  98         u64 addr;
  99         int i;
 100         int ret = nents;
 101
 102         BUG_ON(!valid_dma_direction(direction));
 103
 104         for_each_sg(sgl, sg, nents, i) {
 105                 addr = (u64) page_address(sg_page(sg));
 106                 /* TODO: handle highmem pages */
 107                 if (!addr) {
 108                         ret = 0;
 109                         break;
 110                 }
 111                 sg->dma_address = addr + sg->offset;
 112 #ifdef CONFIG_NEED_SG_DMA_LENGTH
 113                 sg->dma_length = sg->length;
 114 #endif
 115         }
 116         return ret;
 117 }
 118
 119 static void qib_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 void qib_sync_single_for_cpu(struct ib_device *dev, u64 addr,
 127                                     size_t size, enum dma_data_direction dir)
 128 {
 129 }
 130
 131 static void qib_sync_single_for_device(struct ib_device *dev, u64 addr,
 132                                        size_t size,
 133                                        enum dma_data_direction dir)
 134 {
 135 }
 136
 137 static void *qib_dma_alloc_coherent(struct ib_device *dev, size_t size,
 138                                     u64 *dma_handle, gfp_t flag)
 139 {
 140         struct page *p;
 141         void *addr = NULL;
 142
 143         p = alloc_pages(flag, get_order(size));
 144         if (p)
 145                 addr = page_address(p);
 146         if (dma_handle)
 147                 *dma_handle = (u64) addr;
 148         return addr;
 149 }
 150
 151 static void qib_dma_free_coherent(struct ib_device *dev, size_t size,
 152                                   void *cpu_addr, u64 dma_handle)
 153 {
 154         free_pages((unsigned long) cpu_addr, get_order(size));
 155 }
 156
 157 struct ib_dma_mapping_ops qib_dma_mapping_ops = {
 158         .mapping_error = qib_mapping_error,
 159         .map_single = qib_dma_map_single,
 160         .unmap_single = qib_dma_unmap_single,
 161         .map_page = qib_dma_map_page,
 162         .unmap_page = qib_dma_unmap_page,
 163         .map_sg = qib_map_sg,
 164         .unmap_sg = qib_unmap_sg,
 165         .sync_single_for_cpu = qib_sync_single_for_cpu,
 166         .sync_single_for_device = qib_sync_single_for_device,
 167         .alloc_coherent = qib_dma_alloc_coherent,
 168         .free_coherent = qib_dma_free_coherent
 169 };