Steins7
ccf36ac400
The dma buffer should be services that are used on top of peripherals. As such, the usart driver should'nt directly use them, this is up to the user. The multi-buffer has also been simplified since I was not satisfied with the previous implementation
100 lines
2.6 KiB
C
100 lines
2.6 KiB
C
/** @file dma_mbuf.h
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* Module handling Direct Memory Access controller's multibuffer system
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*
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* The module provides a convenient tool to send data to a peripheral in a
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* buffered, low-altency, low-cpu usage, 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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#define DMA_CONFIG (DMA_CONFIG_IRQ_COMPLETE | DMA_CONFIG_FROM_MEM \
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| DMA_CONFIG_INC_MEM | DMA_CONFIG_PSIZE_8BITS \
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| DMA_CONFIG_MSIZE_8BITS)
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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,
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const struct DmaParam* param, enum DmaConfig priority,
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void* raw_buffer, uint16_t buffer_size)
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{
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#warning "check for null ptr"
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buffer->raw_buffer = raw_buffer;
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buffer->param = param;
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buffer->priority = priority;
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buffer->buffer_size = buffer_size / 2;
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buffer->byte_index = 0;
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buffer->buffer_index = 0;
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buffer->dma_running = false;
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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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//if the current buffer is full, give up
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if (buffer->byte_index >= buffer->buffer_size) {
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return 1;
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}
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//write the byte
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buffer->raw_buffer[buffer->buffer_index * buffer->buffer_size
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+ buffer->byte_index] = byte;
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++buffer->byte_index;
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return 0;
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}
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void dma_mbuf_switch(volatile struct DmaMultiBuffer* buffer)
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{
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//if transfer already in progress or no data to send, don't start the
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//transfer
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if (buffer->dma_running || buffer->byte_index == 0) {
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return;
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}
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//start a new transfer
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dma_configure(buffer->param->dma, buffer->param->channel,
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DMA_CONFIG | buffer->param->config | buffer->priority,
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buffer->param->periph,
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&buffer->raw_buffer[buffer->buffer_index * buffer->buffer_size],
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buffer->byte_index, mbuf_callback, buffer);
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buffer->dma_running = true;
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buffer->byte_index = 0;
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++buffer->buffer_index;
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if (buffer->buffer_index > 1) {
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buffer->buffer_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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buffer->dma_running = false;
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}
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