FreeBSD/Linux Kernel Cross Reference
sys/dev/mlx5/doorbell.h

     /*-
      * 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.
     *
     * $FreeBSD$
     */
    
    #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;
    
            spin_lock_irqsave(doorbell_lock, flags);
            __raw_writel((__force u32) val[0], dest);
            __raw_writel((__force u32) val[1], dest + 4);
            spin_unlock_irqrestore(doorbell_lock, flags);
    }
    
    #endif
    
    #endif /* MLX5_DOORBELL_H */

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