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/**
* @file
*
* @ingroup RTEMSBSPsARMLPC176X_dma
*
* @brief Direct memory access (DMA) support.
*/
/*
* Copyright (c) 2008-2011 embedded brains GmbH. All rights reserved.
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#include <rtems/endian.h>
#include <bsp/dma.h>
#include <bsp/io.h>
/**
* @brief Table that indicates if a channel is currently occupied.
*/
static bool lpc176x_dma_channel_occupation[ GPDMA_CH_NUMBER ];
void lpc176x_dma_initialize( void )
{
/* Enable module power */
lpc176x_module_enable( LPC176X_MODULE_GPDMA, LPC176X_MODULE_PCLK_DEFAULT );
/* Disable module */
GPDMA_CONFIG = 0u;
/* Reset registers */
GPDMA_SOFT_SREQ = 0u;
GPDMA_SOFT_BREQ = 0u;
GPDMA_SOFT_LSREQ = 0u;
GPDMA_SOFT_LBREQ = 0u;
GPDMA_SYNC = 0u;
GPDMA_CH0_CFG = 0u;
GPDMA_CH1_CFG = 0u;
/* Enable module */
#if BYTE_ORDER == LITTLE_ENDIAN
GPDMA_CONFIG = GPDMA_CONFIG_EN;
#else
GPDMA_CONFIG = GPDMA_CONFIG_EN | GPDMA_CONFIG_MODE;
#endif
}
rtems_status_code lpc176x_dma_channel_obtain( const unsigned channel )
{
rtems_status_code status_code = RTEMS_INVALID_ID;
if ( channel < GPDMA_CH_NUMBER ) {
rtems_interrupt_level level = 0u;
bool occupation = true;
rtems_interrupt_disable( level );
occupation = lpc176x_dma_channel_occupation[ channel ];
lpc176x_dma_channel_occupation[ channel ] = true;
rtems_interrupt_enable( level );
status_code = occupation ? RTEMS_RESOURCE_IN_USE : RTEMS_SUCCESSFUL;
}
/* else implies that the channel is not valid. Also,
there is nothing to do. */
return status_code;
}
void lpc176x_dma_channel_release( const unsigned channel )
{
if ( channel < GPDMA_CH_NUMBER ) {
lpc176x_dma_channel_occupation[ channel ] = false;
}
/* else implies that the channel is not valid. Also,
there is nothing to do. */
}
void lpc176x_dma_channel_disable(
const unsigned channel,
const bool force
)
{
if ( channel < GPDMA_CH_NUMBER ) {
volatile lpc176x_dma_channel *ch = GPDMA_CH_BASE_ADDR( channel );
uint32_t cfg = ch->cfg;
if ( !force ) {
/* Halt */
ch->cfg |= GPDMA_CH_CFG_HALT;
/* Wait for inactive */
do {
cfg = ch->cfg;
} while ( ( cfg & GPDMA_CH_CFG_ACTIVE ) != 0u );
}
/* else implies that the channel is not to be forced. Also,
there is nothing to do. */
/* Disable */
ch->cfg &= ~GPDMA_CH_CFG_EN;
}
/* else implies that the channel is not valid. Also,
there is nothing to do. */
}
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