alt_dma_rxchan_open.c

nios中自定义指令集实现三角函数的软件部分。

/******************************************************************************
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* License Agreement                                                           *
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* Copyright (c) 2004 Altera Corporation, San Jose, California, USA.           *
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/******************************************************************************
*                                                                             *
* THIS IS A LIBRARY READ-ONLY SOURCE FILE. DO NOT EDIT IT DIRECTLY.           *
*                                                                             *
* Overriding HAL Functions                                                    *
*                                                                             *
* To provide your own implementation of a HAL function, include the file in   *
* your Nios II IDE application project. When building the executable, the     *
* Nios II IDE finds your function first, and uses it in place of the HAL      *
* version.                                                                    *
*                                                                             *
******************************************************************************/

#include "sys/alt_dma.h"
#include "sys/alt_errno.h"
#include "priv/alt_file.h"

/*
 * The list of registered DMA receive channels.
 */

ALT_LLIST_HEAD(alt_dma_rxchan_list);

/*
 * alt_dma_txchan_open() is used to obtain an "alt_dma_txchan" descriptor for
 * a DMA transmit device. The name is the name of the associated physical
 * device (e.g. "/dev/dma_0").
 *
 * The return value will be NULL on failure, and non-NULL otherwise. 
 */

alt_dma_rxchan alt_dma_rxchan_open (const char* name)
{
  alt_dma_rxchan dev;

  dev = (alt_dma_rxchan) alt_find_dev (name, &alt_dma_rxchan_list);

  if (!dev)
  {
    ALT_ERRNO = ENODEV;
  }

  return dev;
}