FreeBSD/Linux Kernel Cross Reference
sys/dev/mlx4/doorbell.h

     /*
      * Copyright (c) 2004 Topspin Communications.  All rights reserved.
      * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
      * Copyright (c) 2005 Mellanox Technologies. All rights reserved.
      *
      * This software is available to you under a choice of one of two
      * licenses.  You may choose to be licensed under the terms of the GNU
      * General Public License (GPL) Version 2, available from the file
      * COPYING in the main directory of this source tree, or the
     * OpenIB.org BSD license below:
     *
     *     Redistribution and use in source and binary forms, with or
     *     without modification, are permitted provided that the following
     *     conditions are met:
     *
     *      - Redistributions of source code must retain the above
     *        copyright notice, this list of conditions and the following
     *        disclaimer.
     *
     *      - 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.
     *
     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
     * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
     * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
     * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
     * SOFTWARE.
     */
    
    #ifndef MLX4_DOORBELL_H
    #define MLX4_DOORBELL_H
    
    #include <linux/types.h>
    #include <linux/io.h>
    
    #define MLX4_SEND_DOORBELL    0x14
    #define MLX4_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 MLX4_DECLARE_DOORBELL_LOCK(name)
    #define MLX4_INIT_DOORBELL_LOCK(ptr)    do { } while (0)
    #define MLX4_GET_DOORBELL_LOCK(ptr)      (NULL)
    
    static inline void mlx4_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 MLX4_DECLARE_DOORBELL_LOCK(name) spinlock_t name;
    #define MLX4_INIT_DOORBELL_LOCK(ptr)     spin_lock_init(ptr)
    #define MLX4_GET_DOORBELL_LOCK(ptr)      (ptr)
    
    static inline void mlx4_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], (u8 *)dest + 4);
            spin_unlock_irqrestore(doorbell_lock, flags);
    }
    
    #endif
    
    #endif /* MLX4_DOORBELL_H */

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