LXR linux/include/linux/mlx5/doorbell.h

   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#if BITS_PER_LONG == 64
  40/* Assume that we can just write a 64-bit doorbell atomically.  s390
  41 * actually doesn't have writeq() but S/390 systems don't even have
  42 * PCI so we won't worry about it.
  43 */
  44
  45#define MLX5_DECLARE_DOORBELL_LOCK(name)
  46#define MLX5_INIT_DOORBELL_LOCK(ptr)    do { } while (0)
  47#define MLX5_GET_DOORBELL_LOCK(ptr)      (NULL)
  48
  49static inline void mlx5_write64(__be32 val[2], void __iomem *dest,
  50                                spinlock_t *doorbell_lock)
  51{
  52        __raw_writeq(*(u64 *)val, dest);
  53}
  54
  55#else
  56
  57/* Just fall back to a spinlock to protect the doorbell if
  58 * BITS_PER_LONG is 32 -- there's no portable way to do atomic 64-bit
  59 * MMIO writes.
  60 */
  61
  62#define MLX5_DECLARE_DOORBELL_LOCK(name) spinlock_t name;
  63#define MLX5_INIT_DOORBELL_LOCK(ptr)     spin_lock_init(ptr)
  64#define MLX5_GET_DOORBELL_LOCK(ptr)      (ptr)
  65
  66static inline void mlx5_write64(__be32 val[2], void __iomem *dest,
  67                                spinlock_t *doorbell_lock)
  68{
  69        unsigned long flags;
  70
  71        spin_lock_irqsave(doorbell_lock, flags);
  72        __raw_writel((__force u32) val[0], dest);
  73        __raw_writel((__force u32) val[1], dest + 4);
  74        spin_unlock_irqrestore(doorbell_lock, flags);
  75}
  76
  77#endif
  78
  79#endif /* MLX5_DOORBELL_H */
  80