linux/mlx5/doorbell.h

0001 /*
0002  * Copyright (c) 2013-2015, Mellanox Technologies. All rights reserved.
0003  *
0004  * This software is available to you under a choice of one of two
0005  * licenses.  You may choose to be licensed under the terms of the GNU
0006  * General Public License (GPL) Version 2, available from the file
0007  * COPYING in the main directory of this source tree, or the
0008  * OpenIB.org BSD license below:
0009  *
0010  *     Redistribution and use in source and binary forms, with or
0011  *     without modification, are permitted provided that the following
0012  *     conditions are met:
0013  *
0014  *      - Redistributions of source code must retain the above
0015  *        copyright notice, this list of conditions and the following
0016  *        disclaimer.
0017  *
0018  *      - Redistributions in binary form must reproduce the above
0019  *        copyright notice, this list of conditions and the following
0020  *        disclaimer in the documentation and/or other materials
0021  *        provided with the distribution.
0022  *
0023  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
0024  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
0025  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
0026  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
0027  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
0028  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
0029  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
0030  * SOFTWARE.
0031  */
0032
0033 #ifndef MLX5_DOORBELL_H
0034 #define MLX5_DOORBELL_H
0035
0036 #define MLX5_BF_OFFSET        0x800
0037 #define MLX5_CQ_DOORBELL      0x20
0038
0039 /* Assume that we can just write a 64-bit doorbell atomically.  s390
0040  * actually doesn't have writeq() but S/390 systems don't even have
0041  * PCI so we won't worry about it.
0042  *
0043  * Note that the write is not atomic on 32-bit systems! In contrast to 64-bit
0044  * ones, it requires proper locking. mlx5_write64 doesn't do any locking, so use
0045  * it at your own discretion, protected by some kind of lock on 32 bits.
0046  *
0047  * TODO: use write{q,l}_relaxed()
0048  */
0049
0050 static inline void mlx5_write64(__be32 val[2], void __iomem *dest)
0051 {
0052 #if BITS_PER_LONG == 64
0053     __raw_writeq(*(u64 *)val, dest);
0054 #else
0055     __raw_writel((__force u32) val[0], dest);
0056     __raw_writel((__force u32) val[1], dest + 4);
0057 #endif
0058 }
0059
0060 #endif /* MLX5_DOORBELL_H */