mirror of https://github.com/ARMmbed/mbed-os.git
71 lines
2.5 KiB
C
71 lines
2.5 KiB
C
/*
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* Copyright (c) 2016, Freescale Semiconductor, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* o Redistributions of source code must retain the above copyright notice, this list
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* of conditions and the following disclaimer.
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*
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* o Redistributions in binary form must reproduce the above copyright notice, this
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* list of conditions and the following disclaimer in the documentation and/or
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* other materials provided with the distribution.
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*
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* o Neither the name of Freescale Semiconductor, Inc. nor the names of its
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* contributors may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "fsl_dmamux.h"
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#include "dma_api.h"
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uint32_t channels = 0; // Bit vector of taken channels
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void dma_init(void)
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{
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/* DMA MUX init */
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DMAMUX_Init(DMAMUX0);
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}
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int dma_channel_allocate(uint32_t capabilities)
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{
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int i;
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for (i = 0; i < FSL_FEATURE_DMAMUX_DMAMUX_CHANNELS; i++) {
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if ((channels & (1 << i)) == 0) {
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// Channel available
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channels |= 1 << i;
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/* Check if we need to set the source and enable the MUX for this channel */
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if (capabilities != kDmaRequestMux0Disable) {
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DMAMUX_SetSource(DMAMUX0, i, capabilities);
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DMAMUX_EnableChannel(DMAMUX0, i);
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}
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return i;
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}
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}
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// Couldn't find a channel.
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return DMA_ERROR_OUT_OF_CHANNELS;
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}
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int dma_channel_free(int channelid)
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{
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channels &= ~(1 << channelid);
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DMAMUX_DisableChannel(DMAMUX0, channelid);
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return 0;
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}
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