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
77 lines
2.4 KiB
C
77 lines
2.4 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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#ifndef _DMA_MBUF_H_
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#define _DMA_MBUF_H_
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//--includes--------------------------------------------------------------------
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#include "../drv/dma.h"
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//--type definitions------------------------------------------------------------
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/**
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* Struct used by the multibuffer system. This system allows bufferized writes
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* to a peripheral with no latency, minimal cpu usage and customisable buffer
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* sizes
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*/
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struct DmaMultiBuffer {
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uint8_t* raw_buffer;
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const struct DmaParam* param;
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enum DmaConfig priority;
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uint16_t buffer_size;
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uint8_t byte_index;
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uint8_t buffer_index;
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bool dma_running;
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};
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//--functions-------------------------------------------------------------------
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/**
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* Configure a DMA multibuffer for a single DMA channel. A list of buffers is
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* used to allow concurent write and DMA tranfers to the specified destination
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* wich must be a peripheral. The DMA's priority is also given as parameters.
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* The peripheral's specific configuration must be handled separately. 2 bytes
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* are reserved in each buffer for index storage.
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*
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* This system needs to be started manually: dma_mbuf_refresh() should be called
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* whenever a DMA transfer can be started. This can be done manually after
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* filling up the buffer. Transfers will then automatically be started as long
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* as there are bytes in the buffer. See the usart module for an usage exemple
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*/
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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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* Write the given byte to the given buffer. Returns 0 if the write operation
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* was successfull, 1 otherwise. The function is non-blocking.
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*
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* Note: calling this function will not trigger a DMA transfer, see
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* dma_mbuf_refresh() to do that
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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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* Refresh the buffer state, checking for bytes to send and triggering a DMA
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* transfer if necessary. Should be called for the first transfer, any remaining
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* transfer will be handled automatically until there are no bytes left in the
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* buffer
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*/
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void dma_mbuf_switch(volatile struct DmaMultiBuffer* buffer);
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#endif //_DMA_MBUF_H_
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