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	}
119	return ret;
120}
121
122static void ipath_unmap_sg(struct ib_device *dev,
123			   struct scatterlist *sg, int nents,
124			   enum dma_data_direction direction)
125{
126	BUG_ON(!valid_dma_direction(direction));
127}
128
129static u64 ipath_sg_dma_address(struct ib_device *dev, struct scatterlist *sg)
130{
131	u64 addr = (u64) page_address(sg_page(sg));
132
133	if (addr)
134		addr += sg->offset;
135	return addr;
136}
137
138static unsigned int ipath_sg_dma_len(struct ib_device *dev,
139				     struct scatterlist *sg)
140{
141	return sg->length;
142}
143
144static void ipath_sync_single_for_cpu(struct ib_device *dev,
145				      u64 addr,
146				      size_t size,
147				      enum dma_data_direction dir)
148{
149}
150
151static void ipath_sync_single_for_device(struct ib_device *dev,
152					 u64 addr,
153					 size_t size,
154					 enum dma_data_direction dir)
155{
156}
157
158static void *ipath_dma_alloc_coherent(struct ib_device *dev, size_t size,
159				      u64 *dma_handle, gfp_t flag)
160{
161	struct page *p;
162	void *addr = NULL;
163
164	p = alloc_pages(flag, get_order(size));
165	if (p)
166		addr = page_address(p);
167	if (dma_handle)
168		*dma_handle = (u64) addr;
169	return addr;
170}
171
172static void ipath_dma_free_coherent(struct ib_device *dev, size_t size,
173				    void *cpu_addr, u64 dma_handle)
174{
175	free_pages((unsigned long) cpu_addr, get_order(size));
176}
177
178struct ib_dma_mapping_ops ipath_dma_mapping_ops = {
179	ipath_mapping_error,
180	ipath_dma_map_single,
181	ipath_dma_unmap_single,
182	ipath_dma_map_page,
183	ipath_dma_unmap_page,
184	ipath_map_sg,
185	ipath_unmap_sg,
186	ipath_sg_dma_address,
187	ipath_sg_dma_len,
188	ipath_sync_single_for_cpu,
189	ipath_sync_single_for_device,
190	ipath_dma_alloc_coherent,
191	ipath_dma_free_coherent
192};