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	}
112	return ret;
113}
114
115static void qib_unmap_sg(struct ib_device *dev,
116			 struct scatterlist *sg, int nents,
117			 enum dma_data_direction direction)
118{
119	BUG_ON(!valid_dma_direction(direction));
120}
121
122static u64 qib_sg_dma_address(struct ib_device *dev, struct scatterlist *sg)
123{
124	u64 addr = (u64) page_address(sg_page(sg));
125
126	if (addr)
127		addr += sg->offset;
128	return addr;
129}
130
131static unsigned int qib_sg_dma_len(struct ib_device *dev,
132				   struct scatterlist *sg)
133{
134	return sg->length;
135}
136
137static void qib_sync_single_for_cpu(struct ib_device *dev, u64 addr,
138				    size_t size, enum dma_data_direction dir)
139{
140}
141
142static void qib_sync_single_for_device(struct ib_device *dev, u64 addr,
143				       size_t size,
144				       enum dma_data_direction dir)
145{
146}
147
148static void *qib_dma_alloc_coherent(struct ib_device *dev, size_t size,
149				    u64 *dma_handle, gfp_t flag)
150{
151	struct page *p;
152	void *addr = NULL;
153
154	p = alloc_pages(flag, get_order(size));
155	if (p)
156		addr = page_address(p);
157	if (dma_handle)
158		*dma_handle = (u64) addr;
159	return addr;
160}
161
162static void qib_dma_free_coherent(struct ib_device *dev, size_t size,
163				  void *cpu_addr, u64 dma_handle)
164{
165	free_pages((unsigned long) cpu_addr, get_order(size));
166}
167
168struct ib_dma_mapping_ops qib_dma_mapping_ops = {
169	.mapping_error = qib_mapping_error,
170	.map_single = qib_dma_map_single,
171	.unmap_single = qib_dma_unmap_single,
172	.map_page = qib_dma_map_page,
173	.unmap_page = qib_dma_unmap_page,
174	.map_sg = qib_map_sg,
175	.unmap_sg = qib_unmap_sg,
176	.dma_address = qib_sg_dma_address,
177	.dma_len = qib_sg_dma_len,
178	.sync_single_for_cpu = qib_sync_single_for_cpu,
179	.sync_single_for_device = qib_sync_single_for_device,
180	.alloc_coherent = qib_dma_alloc_coherent,
181	.free_coherent = qib_dma_free_coherent
182};