1 /*
2 * Copyright (c) 2007 Cisco Systems, Inc. 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/slab.h>
34
35 #include "mlx4_ib.h"
36
37 struct mlx4_ib_db_pgdir {
38 struct list_head list;
39 DECLARE_BITMAP(order0, MLX4_IB_DB_PER_PAGE);
40 DECLARE_BITMAP(order1, MLX4_IB_DB_PER_PAGE / 2);
41 unsigned long *bits[2];
42 __be32 *db_page;
43 dma_addr_t db_dma;
44 };
45
46 static struct mlx4_ib_db_pgdir *mlx4_ib_alloc_db_pgdir(struct mlx4_ib_dev *dev)
47 {
48 struct mlx4_ib_db_pgdir *pgdir;
49
50 pgdir = kzalloc(sizeof *pgdir, GFP_KERNEL);
51 if (!pgdir)
52 return NULL;
53
54 bitmap_fill(pgdir->order1, MLX4_IB_DB_PER_PAGE / 2);
55 pgdir->bits[0] = pgdir->order0;
56 pgdir->bits[1] = pgdir->order1;
57 pgdir->db_page = dma_alloc_coherent(dev->ib_dev.dma_device,
58 PAGE_SIZE, &pgdir->db_dma,
59 GFP_KERNEL);
60 if (!pgdir->db_page) {
61 kfree(pgdir);
62 return NULL;
63 }
64
65 return pgdir;
66 }
67
68 static int mlx4_ib_alloc_db_from_pgdir(struct mlx4_ib_db_pgdir *pgdir,
69 struct mlx4_ib_db *db, int order)
70 {
71 int o;
72 int i;
73
74 for (o = order; o <= 1; ++o) {
75 i = find_first_bit(pgdir->bits[o], MLX4_IB_DB_PER_PAGE >> o);
76 if (i < MLX4_IB_DB_PER_PAGE >> o)
77 goto found;
78 }
79
80 return -ENOMEM;
81
82 found:
83 clear_bit(i, pgdir->bits[o]);
84
85 i <<= o;
86
87 if (o > order)
88 set_bit(i ^ 1, pgdir->bits[order]);
89
90 db->u.pgdir = pgdir;
91 db->index = i;
92 db->db = pgdir->db_page + db->index;
93 db->dma = pgdir->db_dma + db->index * 4;
94 db->order = order;
95
96 return 0;
97 }
98
99 int mlx4_ib_db_alloc(struct mlx4_ib_dev *dev, struct mlx4_ib_db *db, int order)
100 {
101 struct mlx4_ib_db_pgdir *pgdir;
102 int ret = 0;
103
104 mutex_lock(&dev->pgdir_mutex);
105
106 list_for_each_entry(pgdir, &dev->pgdir_list, list)
107 if (!mlx4_ib_alloc_db_from_pgdir(pgdir, db, order))
108 goto out;
109
110 pgdir = mlx4_ib_alloc_db_pgdir(dev);
111 if (!pgdir) {
112 ret = -ENOMEM;
113 goto out;
114 }
115
116 list_add(&pgdir->list, &dev->pgdir_list);
117
118 /* This should never fail -- we just allocated an empty page: */
119 WARN_ON(mlx4_ib_alloc_db_from_pgdir(pgdir, db, order));
120
121 out:
122 mutex_unlock(&dev->pgdir_mutex);
123
124 return ret;
125 }
126
127 void mlx4_ib_db_free(struct mlx4_ib_dev *dev, struct mlx4_ib_db *db)
128 {
129 int o;
130 int i;
131
132 mutex_lock(&dev->pgdir_mutex);
133
134 o = db->order;
135 i = db->index;
136
137 if (db->order == 0 && test_bit(i ^ 1, db->u.pgdir->order0)) {
138 clear_bit(i ^ 1, db->u.pgdir->order0);
139 ++o;
140 }
141
142 i >>= o;
143 set_bit(i, db->u.pgdir->bits[o]);
144
145 if (bitmap_full(db->u.pgdir->order1, MLX4_IB_DB_PER_PAGE / 2)) {
146 dma_free_coherent(dev->ib_dev.dma_device, PAGE_SIZE,
147 db->u.pgdir->db_page, db->u.pgdir->db_dma);
148 list_del(&db->u.pgdir->list);
149 kfree(db->u.pgdir);
150 }
151
152 mutex_unlock(&dev->pgdir_mutex);
153 }
154
155 struct mlx4_ib_user_db_page {
156 struct list_head list;
157 struct ib_umem *umem;
158 unsigned long user_virt;
159 int refcnt;
160 };
161
162 int mlx4_ib_db_map_user(struct mlx4_ib_ucontext *context, unsigned long virt,
163 struct mlx4_ib_db *db)
164 {
165 struct mlx4_ib_user_db_page *page;
166 struct ib_umem_chunk *chunk;
167 int err = 0;
168
169 mutex_lock(&context->db_page_mutex);
170
171 list_for_each_entry(page, &context->db_page_list, list)
172 if (page->user_virt == (virt & PAGE_MASK))
173 goto found;
174
175 page = kmalloc(sizeof *page, GFP_KERNEL);
176 if (!page) {
177 err = -ENOMEM;
178 goto out;
179 }
180
181 page->user_virt = (virt & PAGE_MASK);
182 page->refcnt = 0;
183 page->umem = ib_umem_get(&context->ibucontext, virt & PAGE_MASK,
184 PAGE_SIZE, 0);
185 if (IS_ERR(page->umem)) {
186 err = PTR_ERR(page->umem);
187 kfree(page);
188 goto out;
189 }
190
191 list_add(&page->list, &context->db_page_list);
192
193 found:
194 chunk = list_entry(page->umem->chunk_list.next, struct ib_umem_chunk, list);
195 db->dma = sg_dma_address(chunk->page_list) + (virt & ~PAGE_MASK);
196 db->u.user_page = page;
197 ++page->refcnt;
198
199 out:
200 mutex_unlock(&context->db_page_mutex);
201
202 return err;
203 }
204
205 void mlx4_ib_db_unmap_user(struct mlx4_ib_ucontext *context, struct mlx4_ib_db *db)
206 {
207 mutex_lock(&context->db_page_mutex);
208
209 if (!--db->u.user_page->refcnt) {
210 list_del(&db->u.user_page->list);
211 ib_umem_release(db->u.user_page->umem);
212 kfree(db->u.user_page);
213 }
214
215 mutex_unlock(&context->db_page_mutex);
216 }
217
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