summaryrefslogtreecommitdiffstats
path: root/drivers/infiniband/sw/rdmavt/dma.c
blob: 01f71caa3ac4f95994e20b72fedd91cb09a3fb9e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
/*
 * Copyright(c) 2016 Intel Corporation.
 *
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * BSD LICENSE
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *  - Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  - Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *  - Neither the name of Intel Corporation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include <linux/types.h>
#include <linux/scatterlist.h>
#include <rdma/ib_verbs.h>

#include "dma.h"

#define BAD_DMA_ADDRESS ((u64)0)

/*
 * The following functions implement driver specific replacements
 * for the ib_dma_*() functions.
 *
 * These functions return kernel virtual addresses instead of
 * device bus addresses since the driver uses the CPU to copy
 * data instead of using hardware DMA.
 */

static int rvt_mapping_error(struct ib_device *dev, u64 dma_addr)
{
	return dma_addr == BAD_DMA_ADDRESS;
}

static u64 rvt_dma_map_single(struct ib_device *dev, void *cpu_addr,
			      size_t size, enum dma_data_direction direction)
{
	if (WARN_ON(!valid_dma_direction(direction)))
		return BAD_DMA_ADDRESS;

	return (u64)cpu_addr;
}

static void rvt_dma_unmap_single(struct ib_device *dev, u64 addr, size_t size,
				 enum dma_data_direction direction)
{
	/* This is a stub, nothing to be done here */
}

static u64 rvt_dma_map_page(struct ib_device *dev, struct page *page,
			    unsigned long offset, size_t size,
			    enum dma_data_direction direction)
{
	u64 addr;

	if (WARN_ON(!valid_dma_direction(direction)))
		return BAD_DMA_ADDRESS;

	if (offset + size > PAGE_SIZE)
		return BAD_DMA_ADDRESS;

	addr = (u64)page_address(page);
	if (addr)
		addr += offset;

	return addr;
}

static void rvt_dma_unmap_page(struct ib_device *dev, u64 addr, size_t size,
			       enum dma_data_direction direction)
{
	/* This is a stub, nothing to be done here */
}

static int rvt_map_sg(struct ib_device *dev, struct scatterlist *sgl,
		      int nents, enum dma_data_direction direction)
{
	struct scatterlist *sg;
	u64 addr;
	int i;
	int ret = nents;

	if (WARN_ON(!valid_dma_direction(direction)))
		return 0;

	for_each_sg(sgl, sg, nents, i) {
		addr = (u64)page_address(sg_page(sg));
		if (!addr) {
			ret = 0;
			break;
		}
		sg->dma_address = addr + sg->offset;
#ifdef CONFIG_NEED_SG_DMA_LENGTH
		sg->dma_length = sg->length;
#endif
	}
	return ret;
}

static void rvt_unmap_sg(struct ib_device *dev,
			 struct scatterlist *sg, int nents,
			 enum dma_data_direction direction)
{
	/* This is a stub, nothing to be done here */
}

static int rvt_map_sg_attrs(struct ib_device *dev, struct scatterlist *sgl,
			    int nents, enum dma_data_direction direction,
			    unsigned long attrs)
{
	return rvt_map_sg(dev, sgl, nents, direction);
}

static void rvt_unmap_sg_attrs(struct ib_device *dev,
			       struct scatterlist *sg, int nents,
			       enum dma_data_direction direction,
			       unsigned long attrs)
{
	return rvt_unmap_sg(dev, sg, nents, direction);
}

static void rvt_sync_single_for_cpu(struct ib_device *dev, u64 addr,
				    size_t size, enum dma_data_direction dir)
{
}

static void rvt_sync_single_for_device(struct ib_device *dev, u64 addr,
				       size_t size,
				       enum dma_data_direction dir)
{
}

static void *rvt_dma_alloc_coherent(struct ib_device *dev, size_t size,
				    u64 *dma_handle, gfp_t flag)
{
	struct page *p;
	void *addr = NULL;

	p = alloc_pages(flag, get_order(size));
	if (p)
		addr = page_address(p);
	if (dma_handle)
		*dma_handle = (u64)addr;
	return addr;
}

static void rvt_dma_free_coherent(struct ib_device *dev, size_t size,
				  void *cpu_addr, u64 dma_handle)
{
	free_pages((unsigned long)cpu_addr, get_order(size));
}

struct ib_dma_mapping_ops rvt_default_dma_mapping_ops = {
	.mapping_error = rvt_mapping_error,
	.map_single = rvt_dma_map_single,
	.unmap_single = rvt_dma_unmap_single,
	.map_page = rvt_dma_map_page,
	.unmap_page = rvt_dma_unmap_page,
	.map_sg = rvt_map_sg,
	.unmap_sg = rvt_unmap_sg,
	.map_sg_attrs = rvt_map_sg_attrs,
	.unmap_sg_attrs = rvt_unmap_sg_attrs,
	.sync_single_for_cpu = rvt_sync_single_for_cpu,
	.sync_single_for_device = rvt_sync_single_for_device,
	.alloc_coherent = rvt_dma_alloc_coherent,
	.free_coherent = rvt_dma_free_coherent
};