/* SPDX-License-Identifier: BSD-2-Clause */
/**
* @file
*
* @ingroup RTEMSBSPsARMLPC176X_dma
*
* @brief Direct memory access (DMA) support.
*/
/*
* Copyright (c) 2008-2011 embedded brains GmbH. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#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. */
}
