drivers/infiniband/sw/rdmavt/dma.c

   1 /*
   2  * Copyright(c) 2016 Intel Corporation.
   3  *
   4  * This file is provided under a dual BSD/GPLv2 license.  When using or
   5  * redistributing this file, you may do so under either license.
   6  *
   7  * GPL LICENSE SUMMARY
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of version 2 of the GNU General Public License as
  11  * published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * General Public License for more details.
  17  *
  18  * BSD LICENSE
  19  *
  20  * Redistribution and use in source and binary forms, with or without
  21  * modification, are permitted provided that the following conditions
  22  * are met:
  23  *
  24  *  - Redistributions of source code must retain the above copyright
  25  *    notice, this list of conditions and the following disclaimer.
  26  *  - Redistributions in binary form must reproduce the above copyright
  27  *    notice, this list of conditions and the following disclaimer in
  28  *    the documentation and/or other materials provided with the
  29  *    distribution.
  30  *  - Neither the name of Intel Corporation nor the names of its
  31  *    contributors may be used to endorse or promote products derived
  32  *    from this software without specific prior written permission.
  33  *
  34  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  35  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  36  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  37  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  38  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  39  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  40  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  41  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  42  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  43  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  44  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  45  *
  46  */
  47 #include <linux/types.h>
  48 #include <linux/scatterlist.h>
  49 #include <rdma/ib_verbs.h>
  50
  51 #include "dma.h"
  52
  53 #define BAD_DMA_ADDRESS ((u64)0)
  54
  55 /*
  56  * The following functions implement driver specific replacements
  57  * for the ib_dma_*() functions.
  58  *
  59  * These functions return kernel virtual addresses instead of
  60  * device bus addresses since the driver uses the CPU to copy
  61  * data instead of using hardware DMA.
  62  */
  63
  64 static int rvt_mapping_error(struct ib_device *dev, u64 dma_addr)
  65 {
  66         return dma_addr == BAD_DMA_ADDRESS;
  67 }
  68
  69 static u64 rvt_dma_map_single(struct ib_device *dev, void *cpu_addr,
  70                               size_t size, enum dma_data_direction direction)
  71 {
  72         if (WARN_ON(!valid_dma_direction(direction)))
  73                 return BAD_DMA_ADDRESS;
  74
  75         return (u64)cpu_addr;
  76 }
  77
  78 static void rvt_dma_unmap_single(struct ib_device *dev, u64 addr, size_t size,
  79                                  enum dma_data_direction direction)
  80 {
  81         /* This is a stub, nothing to be done here */
  82 }
  83
  84 static u64 rvt_dma_map_page(struct ib_device *dev, struct page *page,
  85                             unsigned long offset, size_t size,
  86                             enum dma_data_direction direction)
  87 {
  88         u64 addr;
  89
  90         if (WARN_ON(!valid_dma_direction(direction)))
  91                 return BAD_DMA_ADDRESS;
  92
  93         addr = (u64)page_address(page);
  94         if (addr)
  95                 addr += offset;
  96
  97         return addr;
  98 }
  99
 100 static void rvt_dma_unmap_page(struct ib_device *dev, u64 addr, size_t size,
 101                                enum dma_data_direction direction)
 102 {
 103         /* This is a stub, nothing to be done here */
 104 }
 105
 106 static int rvt_map_sg(struct ib_device *dev, struct scatterlist *sgl,
 107                       int nents, enum dma_data_direction direction)
 108 {
 109         struct scatterlist *sg;
 110         u64 addr;
 111         int i;
 112         int ret = nents;
 113
 114         if (WARN_ON(!valid_dma_direction(direction)))
 115                 return 0;
 116
 117         for_each_sg(sgl, sg, nents, i) {
 118                 addr = (u64)page_address(sg_page(sg));
 119                 if (!addr) {
 120                         ret = 0;
 121                         break;
 122                 }
 123                 sg->dma_address = addr + sg->offset;
 124 #ifdef CONFIG_NEED_SG_DMA_LENGTH
 125                 sg->dma_length = sg->length;
 126 #endif
 127         }
 128         return ret;
 129 }
 130
 131 static void rvt_unmap_sg(struct ib_device *dev,
 132                          struct scatterlist *sg, int nents,
 133                          enum dma_data_direction direction)
 134 {
 135         /* This is a stub, nothing to be done here */
 136 }
 137
 138 static int rvt_map_sg_attrs(struct ib_device *dev, struct scatterlist *sgl,
 139                             int nents, enum dma_data_direction direction,
 140                             unsigned long attrs)
 141 {
 142         return rvt_map_sg(dev, sgl, nents, direction);
 143 }
 144
 145 static void rvt_unmap_sg_attrs(struct ib_device *dev,
 146                                struct scatterlist *sg, int nents,
 147                                enum dma_data_direction direction,
 148                                unsigned long attrs)
 149 {
 150         return rvt_unmap_sg(dev, sg, nents, direction);
 151 }
 152
 153 static void rvt_sync_single_for_cpu(struct ib_device *dev, u64 addr,
 154                                     size_t size, enum dma_data_direction dir)
 155 {
 156 }
 157
 158 static void rvt_sync_single_for_device(struct ib_device *dev, u64 addr,
 159                                        size_t size,
 160                                        enum dma_data_direction dir)
 161 {
 162 }
 163
 164 static void *rvt_dma_alloc_coherent(struct ib_device *dev, size_t size,
 165                                     u64 *dma_handle, gfp_t flag)
 166 {
 167         struct page *p;
 168         void *addr = NULL;
 169
 170         p = alloc_pages(flag, get_order(size));
 171         if (p)
 172                 addr = page_address(p);
 173         if (dma_handle)
 174                 *dma_handle = (u64)addr;
 175         return addr;
 176 }
 177
 178 static void rvt_dma_free_coherent(struct ib_device *dev, size_t size,
 179                                   void *cpu_addr, u64 dma_handle)
 180 {
 181         free_pages((unsigned long)cpu_addr, get_order(size));
 182 }
 183
 184 struct ib_dma_mapping_ops rvt_default_dma_mapping_ops = {
 185         .mapping_error = rvt_mapping_error,
 186         .map_single = rvt_dma_map_single,
 187         .unmap_single = rvt_dma_unmap_single,
 188         .map_page = rvt_dma_map_page,
 189         .unmap_page = rvt_dma_unmap_page,
 190         .map_sg = rvt_map_sg,
 191         .unmap_sg = rvt_unmap_sg,
 192         .map_sg_attrs = rvt_map_sg_attrs,
 193         .unmap_sg_attrs = rvt_unmap_sg_attrs,
 194         .sync_single_for_cpu = rvt_sync_single_for_cpu,
 195         .sync_single_for_device = rvt_sync_single_for_device,
 196         .alloc_coherent = rvt_dma_alloc_coherent,
 197         .free_coherent = rvt_dma_free_coherent
 198 };