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 #ifndef MLX5_DOORBELL_H
34 #define MLX5_DOORBELL_H
35
36 #define MLX5_BF_OFFSET 0x800
37 #define MLX5_CQ_DOORBELL 0x20
38
39 /* Assume that we can just write a 64-bit doorbell atomically. s390
40 * actually doesn't have writeq() but S/390 systems don't even have
41 * PCI so we won't worry about it.
42 *
43 * Note that the write is not atomic on 32-bit systems! In contrast to 64-bit
44 * ones, it requires proper locking. mlx5_write64 doesn't do any locking, so use
45 * it at your own discretion, protected by some kind of lock on 32 bits.
46 *
47 * TODO: use write{q,l}_relaxed()
48 */
49
50 static inline void mlx5_write64(__be32 val[2], void __iomem *dest)
51 {
52 #if BITS_PER_LONG == 64
53 __raw_writeq(*(u64 *)val, dest);
54 #else
55 __raw_writel((__force u32) val[0], dest);
56 __raw_writel((__force u32) val[1], dest + 4);
57 #endif
58 }
59
60 #endif /* MLX5_DOORBELL_H */