1/*-
2 * Copyright (c) 2013-2017, Mellanox Technologies, Ltd.  All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS `AS IS' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 *
25 * $FreeBSD: stable/11/sys/dev/mlx5/doorbell.h 337115 2018-08-02 08:56:27Z hselasky $
26 */
27
28#ifndef MLX5_DOORBELL_H
29#define MLX5_DOORBELL_H
30
31#define MLX5_BF_OFFSET	      0x800
32#define MLX5_CQ_DOORBELL      0x20
33
34#if BITS_PER_LONG == 64
35/* Assume that we can just write a 64-bit doorbell atomically.  s390
36 * actually doesn't have writeq() but S/390 systems don't even have
37 * PCI so we won't worry about it.
38 */
39
40#define MLX5_DECLARE_DOORBELL_LOCK(name)
41#define MLX5_INIT_DOORBELL_LOCK(ptr)    do { } while (0)
42#define MLX5_GET_DOORBELL_LOCK(ptr)      (NULL)
43
44static inline void mlx5_write64(__be32 val[2], void __iomem *dest,
45				spinlock_t *doorbell_lock)
46{
47	__raw_writeq(*(u64 *)val, dest);
48}
49
50#else
51
52/* Just fall back to a spinlock to protect the doorbell if
53 * BITS_PER_LONG is 32 -- there's no portable way to do atomic 64-bit
54 * MMIO writes.
55 */
56
57#define MLX5_DECLARE_DOORBELL_LOCK(name) spinlock_t name;
58#define MLX5_INIT_DOORBELL_LOCK(ptr)     spin_lock_init(ptr)
59#define MLX5_GET_DOORBELL_LOCK(ptr)      (ptr)
60
61static inline void mlx5_write64(__be32 val[2], void __iomem *dest,
62				spinlock_t *doorbell_lock)
63{
64	unsigned long flags;
65
66	spin_lock_irqsave(doorbell_lock, flags);
67	__raw_writel((__force u32) val[0], dest);
68	__raw_writel((__force u32) val[1], dest + 4);
69	spin_unlock_irqrestore(doorbell_lock, flags);
70}
71
72#endif
73
74#endif /* MLX5_DOORBELL_H */
75