mbed library sources
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Diff: targets/hal/TARGET_Atmel/TARGET_SAM21/sercom_dma.c
- Revision:
- 579:53297373a894
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/targets/hal/TARGET_Atmel/TARGET_SAM21/sercom_dma.c Wed Jul 01 09:45:11 2015 +0100 @@ -0,0 +1,95 @@ +/* mbed Microcontroller Library + * Copyright (c) 2006-2013 ARM Limited + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +#include "mbed_assert.h" +#include "system.h" + +#include <math.h> + +#include "cmsis.h" +#include "pinmap.h" +#include "sercom.h" +#include "dma_api.h" +#include "dma_api_HAL.h" +#include "sercom_dma.h" + +static struct sercom_dma sercom_channels[SERCOM_INST_NUM] = {{0}}; + +/** Allocate a channel for TX + * + * @param[in] sercom_index index of sercom instance + * @param[out] tx_id pointer to channel id + * @return allocated channel id + */ +uint8_t sercom_setup_tx_channel(uint8_t sercom_index, uint8_t *tx_id) +{ + if (sercom_channels[sercom_index].tx_status & DMA_ALLOCATED) { + *tx_id = sercom_channels[sercom_index].tx_channel_id; + } else { + /* Try to allocate a channel */ + sercom_channels[sercom_index].tx_channel_id = dma_channel_allocate(DMA_CAP_NONE); + if (sercom_channels[sercom_index].tx_channel_id != (uint8_t)DMA_ERROR_OUT_OF_CHANNELS) { + *tx_id = sercom_channels[sercom_index].tx_channel_id; + sercom_channels[sercom_index].tx_status = DMA_ALLOCATED; + } else { + /* Couldn't find a channel */ + return DMA_ERROR_OUT_OF_CHANNELS; + } + } + return *tx_id; +} + +/** Allocate a channel for RX + * + * @param[in] sercom_index index of sercom instance + * @param[out] rx_id pointer to channel id + * @return allocated channel id + */ +uint8_t sercom_setup_rx_channel(uint8_t sercom_index, uint8_t *rx_id) +{ + if (sercom_channels[sercom_index].rx_status & DMA_ALLOCATED) { + *rx_id = sercom_channels[sercom_index].rx_channel_id; + } else { + /* Try to allocate a channel */ + sercom_channels[sercom_index].rx_channel_id = dma_channel_allocate(DMA_CAP_NONE); + if (sercom_channels[sercom_index].rx_channel_id != (uint8_t)DMA_ERROR_OUT_OF_CHANNELS) { + *rx_id = sercom_channels[sercom_index].rx_channel_id; + sercom_channels[sercom_index].rx_status = DMA_ALLOCATED; + } else { + /* Couldn't find a channel */ + return DMA_ERROR_OUT_OF_CHANNELS; + } + } + return *rx_id; +} + +/** Release DMA channels if allocated + * + * @param[in] sercom_index index of sercom instance + * @return void + */ +void sercom_release_channel(uint8_t sercom_index) +{ + if (sercom_channels[sercom_index].rx_status & DMA_ALLOCATED) { + if (0 == dma_channel_free(sercom_channels[sercom_index].rx_channel_id)) { + sercom_channels[sercom_index].rx_status = DMA_NOT_USED; + } + } + if (sercom_channels[sercom_index].tx_status & DMA_ALLOCATED) { + if (0 == dma_channel_free(sercom_channels[sercom_index].tx_channel_id)) { + sercom_channels[sercom_index].tx_status = DMA_NOT_USED; + } + } +}