ceph/src/dpdk/lib/librte_kni/rte_kni_fifo.h

   1 /*-
   2  *   BSD LICENSE
   3  *
   4  *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
   5  *   All rights reserved.
   6  *
   7  *   Redistribution and use in source and binary forms, with or without
   8  *   modification, are permitted provided that the following conditions
   9  *   are met:
  10  *
  11  *     * Redistributions of source code must retain the above copyright
  12  *       notice, this list of conditions and the following disclaimer.
  13  *     * Redistributions in binary form must reproduce the above copyright
  14  *       notice, this list of conditions and the following disclaimer in
  15  *       the documentation and/or other materials provided with the
  16  *       distribution.
  17  *     * Neither the name of Intel Corporation nor the names of its
  18  *       contributors may be used to endorse or promote products derived
  19  *       from this software without specific prior written permission.
  20  *
  21  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  24  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  25  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  26  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  27  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  31  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34
  35
  36 /**
  37  * Initializes the kni fifo structure
  38  */
  39 static void
  40 kni_fifo_init(struct rte_kni_fifo *fifo, unsigned size)
  41 {
  42         /* Ensure size is power of 2 */
  43         if (size & (size - 1))
  44                 rte_panic("KNI fifo size must be power of 2\n");
  45
  46         fifo->write = 0;
  47         fifo->read = 0;
  48         fifo->len = size;
  49         fifo->elem_size = sizeof(void *);
  50 }
  51
  52 /**
  53  * Adds num elements into the fifo. Return the number actually written
  54  */
  55 static inline unsigned
  56 kni_fifo_put(struct rte_kni_fifo *fifo, void **data, unsigned num)
  57 {
  58         unsigned i = 0;
  59         unsigned fifo_write = fifo->write;
  60         unsigned fifo_read = fifo->read;
  61         unsigned new_write = fifo_write;
  62
  63         for (i = 0; i < num; i++) {
  64                 new_write = (new_write + 1) & (fifo->len - 1);
  65
  66                 if (new_write == fifo_read)
  67                         break;
  68                 fifo->buffer[fifo_write] = data[i];
  69                 fifo_write = new_write;
  70         }
  71         fifo->write = fifo_write;
  72         return i;
  73 }
  74
  75 /**
  76  * Get up to num elements from the fifo. Return the number actully read
  77  */
  78 static inline unsigned
  79 kni_fifo_get(struct rte_kni_fifo *fifo, void **data, unsigned num)
  80 {
  81         unsigned i = 0;
  82         unsigned new_read = fifo->read;
  83         unsigned fifo_write = fifo->write;
  84         for (i = 0; i < num; i++) {
  85                 if (new_read == fifo_write)
  86                         break;
  87
  88                 data[i] = fifo->buffer[new_read];
  89                 new_read = (new_read + 1) & (fifo->len - 1);
  90         }
  91         fifo->read = new_read;
  92         return i;
  93 }