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 
mlx5_write64(__be32 val[2],void __iomem * dest)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 */
61