xref: /freebsd/sys/dev/mlx5/doorbell.h (revision e23731db48ef9c6568d4768b1f87d48514339faa)

/*-
 * Copyright (c) 2013-2017, Mellanox Technologies, Ltd.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS `AS IS' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef MLX5_DOORBELL_H
#define MLX5_DOORBELL_H

#define MLX5_BF_OFFSET	      0x800
#define MLX5_CQ_DOORBELL      0x20

#if BITS_PER_LONG == 64
/* Assume that we can just write a 64-bit doorbell atomically.  s390
 * actually doesn't have writeq() but S/390 systems don't even have
 * PCI so we won't worry about it.
 */

#define MLX5_DECLARE_DOORBELL_LOCK(name)
#define MLX5_INIT_DOORBELL_LOCK(ptr)    do { } while (0)
#define MLX5_GET_DOORBELL_LOCK(ptr)      (NULL)

static inline void mlx5_write64(__be32 val[2], void __iomem *dest,
				spinlock_t *doorbell_lock)
{
	__raw_writeq(*(u64 *)val, dest);
}

#else

/* Just fall back to a spinlock to protect the doorbell if
 * BITS_PER_LONG is 32 -- there's no portable way to do atomic 64-bit
 * MMIO writes.
 */

#define MLX5_DECLARE_DOORBELL_LOCK(name) spinlock_t name;
#define MLX5_INIT_DOORBELL_LOCK(ptr)     spin_lock_init(ptr)
#define MLX5_GET_DOORBELL_LOCK(ptr)      (ptr)

static inline void mlx5_write64(__be32 val[2], void __iomem *dest,
				spinlock_t *doorbell_lock)
{
	unsigned long flags;

	if (doorbell_lock)
		spin_lock_irqsave(doorbell_lock, flags);
	__raw_writel((__force u32) val[0], dest);
	__raw_writel((__force u32) val[1], dest + 4);
	if (doorbell_lock)
		spin_unlock_irqrestore(doorbell_lock, flags);
}

#endif

#endif /* MLX5_DOORBELL_H */