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
48static int qib_mapping_error(struct ib_device *dev, u64 dma_addr)
49{
50	return dma_addr == BAD_DMA_ADDRESS;
51}
52
53static 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
60static 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
66static 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
84done:
85	return addr;
86}
87
88static 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
94static 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
119static 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
126static void qib_sync_single_for_cpu(struct ib_device *dev, u64 addr,
127				    size_t size, enum dma_data_direction dir)
128{
129}
130
131static 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
137static 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
151static 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
157struct 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};
170