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
 64static int rvt_mapping_error(struct ib_device *dev, u64 dma_addr)
 65{
 66	return dma_addr == BAD_DMA_ADDRESS;
 67}
 68
 69static 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
 78static 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
 84static 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	if (offset + size > PAGE_SIZE)
 94		return BAD_DMA_ADDRESS;
 95
 96	addr = (u64)page_address(page);
 97	if (addr)
 98		addr += offset;
 99
100	return addr;
101}
102
103static void rvt_dma_unmap_page(struct ib_device *dev, u64 addr, size_t size,
104			       enum dma_data_direction direction)
105{
106	/* This is a stub, nothing to be done here */
107}
108
109static int rvt_map_sg(struct ib_device *dev, struct scatterlist *sgl,
110		      int nents, enum dma_data_direction direction)
111{
112	struct scatterlist *sg;
113	u64 addr;
114	int i;
115	int ret = nents;
116
117	if (WARN_ON(!valid_dma_direction(direction)))
118		return 0;
119
120	for_each_sg(sgl, sg, nents, i) {
121		addr = (u64)page_address(sg_page(sg));
122		if (!addr) {
123			ret = 0;
124			break;
125		}
126		sg->dma_address = addr + sg->offset;
127#ifdef CONFIG_NEED_SG_DMA_LENGTH
128		sg->dma_length = sg->length;
129#endif
130	}
131	return ret;
132}
133
134static void rvt_unmap_sg(struct ib_device *dev,
135			 struct scatterlist *sg, int nents,
136			 enum dma_data_direction direction)
137{
138	/* This is a stub, nothing to be done here */
139}
140
141static void rvt_sync_single_for_cpu(struct ib_device *dev, u64 addr,
142				    size_t size, enum dma_data_direction dir)
143{
144}
145
146static void rvt_sync_single_for_device(struct ib_device *dev, u64 addr,
147				       size_t size,
148				       enum dma_data_direction dir)
149{
150}
151
152static void *rvt_dma_alloc_coherent(struct ib_device *dev, size_t size,
153				    u64 *dma_handle, gfp_t flag)
154{
155	struct page *p;
156	void *addr = NULL;
157
158	p = alloc_pages(flag, get_order(size));
159	if (p)
160		addr = page_address(p);
161	if (dma_handle)
162		*dma_handle = (u64)addr;
163	return addr;
164}
165
166static void rvt_dma_free_coherent(struct ib_device *dev, size_t size,
167				  void *cpu_addr, u64 dma_handle)
168{
169	free_pages((unsigned long)cpu_addr, get_order(size));
170}
171
172struct ib_dma_mapping_ops rvt_default_dma_mapping_ops = {
173	.mapping_error = rvt_mapping_error,
174	.map_single = rvt_dma_map_single,
175	.unmap_single = rvt_dma_unmap_single,
176	.map_page = rvt_dma_map_page,
177	.unmap_page = rvt_dma_unmap_page,
178	.map_sg = rvt_map_sg,
179	.unmap_sg = rvt_unmap_sg,
180	.sync_single_for_cpu = rvt_sync_single_for_cpu,
181	.sync_single_for_device = rvt_sync_single_for_device,
182	.alloc_coherent = rvt_dma_alloc_coherent,
183	.free_coherent = rvt_dma_free_coherent
184};