52 lines
2.1 KiB
C
52 lines
2.1 KiB
C
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/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2021 Robert Hammelrath
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "dma_channel.h"
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// List of channel flags: true: channel used, false: channel available
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static bool channel_list[32] = { true, true, true, true, false, false, false, false,
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false, false, false, false, false, false, false, false,
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false, false, false, false, false, false, false, false,
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false, false, false, false, false, false, false, false };
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// allocate_channel(): retrieve an available channel. Return the number or -1
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int allocate_dma_channel(void) {
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for (int i = 0; i < ARRAY_SIZE(channel_list); i++) {
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if (channel_list[i] == false) { // Channel available
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channel_list[i] = true;
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return i;
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}
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}
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return -1;
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}
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// free_channel(n): Declare channel as free
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void free_dma_channel(int n) {
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if (n >= 0 && n <= ARRAY_SIZE(channel_list)) {
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channel_list[n] = false;
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}
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}
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