125 lines
3.3 KiB
C
125 lines
3.3 KiB
C
/** @file dma_mbuf.c
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* Module handling Direct Memory Access controller's TX functions
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*
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* The module provides convenient tools to send data to a peripheral or memory
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* area in a buffered, non-blocking way
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*/
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//--includes--------------------------------------------------------------------
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#include "dma_mbuf.h"
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//--local definitions-----------------------------------------------------------
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static void mbuf_callback(enum DmaIRQSource src, volatile void* param);
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//--local variables-------------------------------------------------------------
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//--public functions------------------------------------------------------------
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void dma_mbuf_configure(volatile struct DmaMultiBuffer* buffer, void** buffers,
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volatile void* dest, uint16_t buffer_size, uint8_t buffer_nb,
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enum DmaPeriph dma, enum DmaChannel channel, enum DmaConfig config)
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{
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#warning "check for null ptr"
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buffer->buffers = buffers;
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buffer->dest = dest;
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buffer->buffer_size = buffer_size;
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buffer->byte_index = 0;
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buffer->buffer_nb = buffer_nb;
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buffer->free_buffer_nb = buffer_nb - 1;
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buffer->buffer_index = 0;
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buffer->dma_buffer_index = 0;
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buffer->dma = dma;
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buffer->channel = channel;
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buffer->config = config;
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}
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uint32_t dma_mbuf_write_byte(volatile struct DmaMultiBuffer* buffer,
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uint8_t byte)
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{
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dma_enter_critical(buffer->dma, buffer->channel);
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//if the current buffer is full, we need to switch it with an empty one
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if (buffer->byte_index >= buffer->buffer_size) {
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//if all buffer full, give up
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if (buffer->free_buffer_nb == 0) {
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dma_exit_critical(buffer->dma, buffer->channel);
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return 1;
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}
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++buffer->buffer_index;
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if (buffer->buffer_index >= buffer->buffer_nb) {
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buffer->buffer_index = 0;
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}
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--buffer->free_buffer_nb;
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buffer->byte_index = 0;
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}
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//write the byte
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uint8_t** buffers = (uint8_t**)buffer->buffers;
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buffers[buffer->buffer_index][buffer->byte_index] = byte;
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++buffer->byte_index;
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dma_exit_critical(buffer->dma, buffer->channel);
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return 0;
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}
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void dma_mbuf_refresh(volatile struct DmaMultiBuffer* buffer)
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{
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//no more data to send, stop here
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if (buffer->dma_buffer_index == buffer->buffer_index
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&& buffer->byte_index == 0) {
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return;
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}
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//else start a new transfer
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dma_configure(buffer->dma, buffer->channel, buffer->config, buffer->dest,
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buffer->buffers[buffer->dma_buffer_index],
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buffer->byte_index, mbuf_callback, buffer);
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//if the newly transfering buffer was being written to, switch the current
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//buffer. Since we just ended a transfer, the next buffer should be empty
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if (buffer->dma_buffer_index == buffer->buffer_index)
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{
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++buffer->buffer_index;
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if (buffer->buffer_index >= buffer->buffer_nb) {
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buffer->buffer_index = 0;
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}
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buffer->byte_index = 0;
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}
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return;
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}
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//--local functions-------------------------------------------------------------
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/**
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* Callback called on DMA TX tranfert's completion. Checks for any remaining
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* data to send. If any, starts a new transfer, else stop the DMA
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*/
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static void mbuf_callback(enum DmaIRQSource src, volatile void* param)
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{
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(void)src; //only transfer complete expected
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volatile struct DmaMultiBuffer* buffer = param;
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//increment DMA's buffer since the last once has already been sent
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++buffer->dma_buffer_index;
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if (buffer->dma_buffer_index >= buffer->buffer_nb) {
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buffer->dma_buffer_index = 0;
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}
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++buffer->free_buffer_nb;
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dma_mbuf_refresh(param);
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}
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