forked from Imagelibrary/rtems
131 lines
3.7 KiB
C
131 lines
3.7 KiB
C
/* SPDX-License-Identifier: BSD-2-Clause */
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/**
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* @file
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*
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* @ingroup RTEMSBSPsARMLPC176X_dma
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*
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* @brief Direct memory access (DMA) support.
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*/
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/*
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* Copyright (c) 2008-2011 embedded brains GmbH. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <rtems/endian.h>
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#include <bsp/dma.h>
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#include <bsp/io.h>
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/**
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* @brief Table that indicates if a channel is currently occupied.
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*/
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static bool lpc176x_dma_channel_occupation[ GPDMA_CH_NUMBER ];
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void lpc176x_dma_initialize( void )
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{
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/* Enable module power */
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lpc176x_module_enable( LPC176X_MODULE_GPDMA, LPC176X_MODULE_PCLK_DEFAULT );
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/* Disable module */
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GPDMA_CONFIG = 0u;
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/* Reset registers */
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GPDMA_SOFT_SREQ = 0u;
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GPDMA_SOFT_BREQ = 0u;
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GPDMA_SOFT_LSREQ = 0u;
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GPDMA_SOFT_LBREQ = 0u;
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GPDMA_SYNC = 0u;
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GPDMA_CH0_CFG = 0u;
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GPDMA_CH1_CFG = 0u;
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/* Enable module */
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#if BYTE_ORDER == LITTLE_ENDIAN
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GPDMA_CONFIG = GPDMA_CONFIG_EN;
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#else
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GPDMA_CONFIG = GPDMA_CONFIG_EN | GPDMA_CONFIG_MODE;
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#endif
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}
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rtems_status_code lpc176x_dma_channel_obtain( const unsigned channel )
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{
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rtems_status_code status_code = RTEMS_INVALID_ID;
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if ( channel < GPDMA_CH_NUMBER ) {
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rtems_interrupt_level level = 0u;
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bool occupation = true;
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rtems_interrupt_disable( level );
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occupation = lpc176x_dma_channel_occupation[ channel ];
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lpc176x_dma_channel_occupation[ channel ] = true;
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rtems_interrupt_enable( level );
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status_code = occupation ? RTEMS_RESOURCE_IN_USE : RTEMS_SUCCESSFUL;
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}
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/* else implies that the channel is not valid. Also,
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there is nothing to do. */
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return status_code;
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}
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void lpc176x_dma_channel_release( const unsigned channel )
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{
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if ( channel < GPDMA_CH_NUMBER ) {
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lpc176x_dma_channel_occupation[ channel ] = false;
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}
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/* else implies that the channel is not valid. Also,
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there is nothing to do. */
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}
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void lpc176x_dma_channel_disable(
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const unsigned channel,
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const bool force
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)
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{
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if ( channel < GPDMA_CH_NUMBER ) {
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volatile lpc176x_dma_channel *ch = GPDMA_CH_BASE_ADDR( channel );
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uint32_t cfg = ch->cfg;
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if ( !force ) {
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/* Halt */
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ch->cfg |= GPDMA_CH_CFG_HALT;
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/* Wait for inactive */
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do {
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cfg = ch->cfg;
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} while ( ( cfg & GPDMA_CH_CFG_ACTIVE ) != 0u );
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}
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/* else implies that the channel is not to be forced. Also,
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there is nothing to do. */
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/* Disable */
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ch->cfg &= ~GPDMA_CH_CFG_EN;
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}
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/* else implies that the channel is not valid. Also,
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there is nothing to do. */
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}
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