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 <linux/scatterlist.h>
34#include <linux/gfp.h>
35#include <rdma/ib_verbs.h>
36
37#include "ipath_verbs.h"
38
39#define BAD_DMA_ADDRESS ((u64) 0)
40
41/*
42 * The following functions implement driver specific replacements
43 * for the ib_dma_*() functions.
44 *
45 * These functions return kernel virtual addresses instead of
46 * device bus addresses since the driver uses the CPU to copy
47 * data instead of using hardware DMA.
48 */
49
50static int ipath_mapping_error(struct ib_device *dev, u64 dma_addr)
51{
52	return dma_addr == BAD_DMA_ADDRESS;
53}
54
55static u64 ipath_dma_map_single(struct ib_device *dev,
56			        void *cpu_addr, size_t size,
57			        enum dma_data_direction direction)
58{
59	BUG_ON(!valid_dma_direction(direction));
60	return (u64) cpu_addr;
61}
62
63static void ipath_dma_unmap_single(struct ib_device *dev,
64				   u64 addr, size_t size,
65				   enum dma_data_direction direction)
66{
67	BUG_ON(!valid_dma_direction(direction));
68}
69
70static u64 ipath_dma_map_page(struct ib_device *dev,
71			      struct page *page,
72			      unsigned long offset,
73			      size_t size,
74			      enum dma_data_direction direction)
75{
76	u64 addr;
77
78	BUG_ON(!valid_dma_direction(direction));
79
80	if (offset + size > PAGE_SIZE) {
81		addr = BAD_DMA_ADDRESS;
82		goto done;
83	}
84
85	addr = (u64) page_address(page);
86	if (addr)
87		addr += offset;
88	/* TODO: handle highmem pages */
89
90done:
91	return addr;
92}
93
94static void ipath_dma_unmap_page(struct ib_device *dev,
95				 u64 addr, size_t size,
96				 enum dma_data_direction direction)
97{
98	BUG_ON(!valid_dma_direction(direction));
99}
100
101static int ipath_map_sg(struct ib_device *dev, struct scatterlist *sgl,
102			int nents, enum dma_data_direction direction)
103{
104	struct scatterlist *sg;
105	u64 addr;
106	int i;
107	int ret = nents;
108
109	BUG_ON(!valid_dma_direction(direction));
110
111	for_each_sg(sgl, sg, nents, i) {
112		addr = (u64) page_address(sg_page(sg));
113		/* TODO: handle highmem pages */
114		if (!addr) {
115			ret = 0;
116			break;
117		}
118		sg->dma_address = addr + sg->offset;
119#ifdef CONFIG_NEED_SG_DMA_LENGTH
120		sg->dma_length = sg->length;
121#endif
122	}
123	return ret;
124}
125
126static void ipath_unmap_sg(struct ib_device *dev,
127			   struct scatterlist *sg, int nents,
128			   enum dma_data_direction direction)
129{
130	BUG_ON(!valid_dma_direction(direction));
131}
132
133static void ipath_sync_single_for_cpu(struct ib_device *dev,
134				      u64 addr,
135				      size_t size,
136				      enum dma_data_direction dir)
137{
138}
139
140static void ipath_sync_single_for_device(struct ib_device *dev,
141					 u64 addr,
142					 size_t size,
143					 enum dma_data_direction dir)
144{
145}
146
147static void *ipath_dma_alloc_coherent(struct ib_device *dev, size_t size,
148				      u64 *dma_handle, gfp_t flag)
149{
150	struct page *p;
151	void *addr = NULL;
152
153	p = alloc_pages(flag, get_order(size));
154	if (p)
155		addr = page_address(p);
156	if (dma_handle)
157		*dma_handle = (u64) addr;
158	return addr;
159}
160
161static void ipath_dma_free_coherent(struct ib_device *dev, size_t size,
162				    void *cpu_addr, u64 dma_handle)
163{
164	free_pages((unsigned long) cpu_addr, get_order(size));
165}
166
167struct ib_dma_mapping_ops ipath_dma_mapping_ops = {
168	.mapping_error = ipath_mapping_error,
169	.map_single = ipath_dma_map_single,
170	.unmap_single = ipath_dma_unmap_single,
171	.map_page = ipath_dma_map_page,
172	.unmap_page = ipath_dma_unmap_page,
173	.map_sg = ipath_map_sg,
174	.unmap_sg = ipath_unmap_sg,
175	.sync_single_for_cpu = ipath_sync_single_for_cpu,
176	.sync_single_for_device = ipath_sync_single_for_device,
177	.alloc_coherent = ipath_dma_alloc_coherent,
178	.free_coherent = ipath_dma_free_coherent
179};
180