Mouse code for the MacroRat
mbed-dev/targets/TARGET_Atmel/TARGET_SAM_CortexM0P/sercom_dma.c
- Committer:
- sahilmgandhi
- Date:
- 2017-05-14
- Revision:
- 18:6a4db94011d3
File content as of revision 18:6a4db94011d3:
/* mbed Microcontroller Library * Copyright (c) 2006-2015 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 "cmsis.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 (uint8_t)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 (uint8_t)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; } } }