1/*
2 * Copyright (c) 2013-2015, Mellanox Technologies. 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 <rdma/ib_umem_odp.h>
34#include "mlx5_ib.h"
35
36/*
37 * Fill in a physical address list. ib_umem_num_dma_blocks() entries will be
38 * filled in the pas array.
39 */
40void mlx5_ib_populate_pas(struct ib_umem *umem, size_t page_size, __be64 *pas,
41 u64 access_flags)
42{
43 struct ib_block_iter biter;
44
45 rdma_umem_for_each_dma_block (umem, &biter, page_size) {
46 *pas = cpu_to_be64(rdma_block_iter_dma_address(&biter) |
47 access_flags);
48 pas++;
49 }
50}
51
52/*
53 * Compute the page shift and page_offset for mailboxes that use a quantized
54 * page_offset. The granulatity of the page offset scales according to page
55 * size.
56 */
57unsigned long __mlx5_umem_find_best_quantized_pgoff(
58 struct ib_umem *umem, unsigned long pgsz_bitmap,
59 unsigned int page_offset_bits, u64 pgoff_bitmask, unsigned int scale,
60 unsigned int *page_offset_quantized)
61{
62 const u64 page_offset_mask = (1UL << page_offset_bits) - 1;
63 unsigned long page_size;
64 u64 page_offset;
65
66 page_size = ib_umem_find_best_pgoff(umem, pgsz_bitmap, pgoff_bitmask);
67 if (!page_size)
68 return 0;
69
70 /*
71 * page size is the largest possible page size.
72 *
73 * Reduce the page_size, and thus the page_offset and quanta, until the
74 * page_offset fits into the mailbox field. Once page_size < scale this
75 * loop is guaranteed to terminate.
76 */
77 page_offset = ib_umem_dma_offset(umem, pgsz: page_size);
78 while (page_offset & ~(u64)(page_offset_mask * (page_size / scale))) {
79 page_size /= 2;
80 page_offset = ib_umem_dma_offset(umem, pgsz: page_size);
81 }
82
83 /*
84 * The address is not aligned, or otherwise cannot be represented by the
85 * page_offset.
86 */
87 if (!(pgsz_bitmap & page_size))
88 return 0;
89
90 *page_offset_quantized =
91 (unsigned long)page_offset / (page_size / scale);
92 if (WARN_ON(*page_offset_quantized > page_offset_mask))
93 return 0;
94 return page_size;
95}
96

source code of linux/drivers/infiniband/hw/mlx5/mem.c