dma.c

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/**
 * \file
 *         Driver for the cc2530 DMA controller. Derived from the cc2430
 *         equivalent
 *
 * \author
 *         Original: Martti Huttunen <martti@sensinode.com>
 *         Port: Zach Shelby <zach@sensinode.com>
 *         Further Modifications:
 *               George Oikonomou <oikonomou@users.sourceforge.net>
 *
 */

#include "contiki.h"
#include "dev/dma.h"
#include "cc253x.h"

#if DMA_ON
struct dma_config dma_conf[DMA_CHANNEL_COUNT]; /* DMA Descriptors */
struct process *dma_callback[DMA_CHANNEL_COUNT];
/*---------------------------------------------------------------------------*/
void
dma_init(void)
{
  uint16_t tmp_ptr;

  memset(dma_conf, 0, 4 * sizeof(dma_config_t));

  for(tmp_ptr = 0; tmp_ptr < DMA_CHANNEL_COUNT; tmp_ptr++) {
    dma_callback[tmp_ptr] = 0;
  }

  /* The address of the descriptor for Channel 0 is configured separately */
  tmp_ptr = (uint16_t)&(dma_conf[0]);
  DMA0CFGH = tmp_ptr >> 8;
  DMA0CFGL = tmp_ptr;

  /*
   * Descriptors for Channels 1-4 must be consecutive in RAM.
   * We write the address of the 1st one to the register and the rest are
   * derived by the SoC
   */
#if (DMA_CHANNEL_COUNT > 1)
  tmp_ptr = (uint16_t)&(dma_conf[1]);
  DMA1CFGH = tmp_ptr >> 8;
  DMA1CFGL = tmp_ptr;
#endif

  DMAIE = 1;    /* Enable DMA interrupts */
}
/*---------------------------------------------------------------------------*/
/*
 * Associate process p with DMA channel c. When a transfer on that channel
 * completes, the ISR will poll this process.
 */
void
dma_associate_process(struct process *p, uint8_t c)
{
  if((!c) || (c >= DMA_CHANNEL_COUNT)) {
    return;
  }

  if(p) {
    dma_conf[c].inc_prio |= 8; /* Enable interrupt generation */
    DMAIE = 1; /* Make sure DMA interrupts are acknowledged */
  }
  dma_callback[c] = p;
}
/*---------------------------------------------------------------------------*/
/*
 * Reset a channel to idle state. As per cc253x datasheet section 8.1,
 * we must reconfigure the channel to trigger source 0 between each
 * reconfiguration.
 */
void
dma_reset(uint8_t c)
{
  static __xdata uint8_t dummy;
  if(c >= DMA_CHANNEL_COUNT) {
    return;
  }
  DMA_ABORT(c);
  dma_conf[c].src_h = (uint16_t)&dummy >> 8;
  dma_conf[c].src_l = (uint16_t)&dummy;
  dma_conf[c].dst_h = (uint16_t)&dummy >> 8;
  dma_conf[c].dst_l = (uint16_t)&dummy;
  dma_conf[c].len_h = 0;
  dma_conf[c].len_l = 1;
  dma_conf[c].wtt = DMA_BLOCK;
  dma_conf[c].inc_prio = DMA_PRIO_ASSURED;
  DMA_TRIGGER(c); /** The operation order is important */
  DMA_ARM(c);
  while(DMAARM & (1 << c));
}
#endif