dma-allocator.c File Reference

This source file contains the implementation of the DMA allocator. More...

#include <bsp.h>
#include <bsp/dma.h>
#include <bsp/fatal.h>
#include <inttypes.h>
#include <rtems/bspIo.h>
#include <rtems/sysinit.h>
#include <stdio.h>
#include <stdlib.h>
#include <stm32h7/hal.h>

Data Structures
struct	stm32h7_dma_context

Typedefs
typedef struct stm32h7_dma_context	stm32h7_dma_context

Functions
DMA_HandleTypeDef *	stm32h7_dma_alloc (void *parent, uint32_t request_type, uint32_t direction, uint32_t priority)
	Acquire a DMA channel.
void	stm32h7_dma_free (DMA_HandleTypeDef *dma_channel)
	Release a DMA channel.

Detailed Description

This source file contains the implementation of the DMA allocator.

Function Documentation

stm32h7_dma_alloc()

DMA_HandleTypeDef * stm32h7_dma_alloc	(	void *	parent,
		uint32_t	request_type,
		uint32_t	direction,
		uint32_t	priority
	)

Acquire a DMA channel.

This function returns a DMA channel that can be used for memory-to-memory, memory-to-peripheral, or peripheral-to-memory transactions. The returned DMA channel is reserved for exclusive use until it is released using stm32h7_dma_free().

Parameters

parent	A pointer to the parent structure that will temporarily own the allocated DMA channel. This should be a *_HandleTypeDef pointer such as SPI_HandleTypeDef
request_type	A DMA_Request_selection value defining the endpoints of the transfer
direction	A DMA_Data_transfer_direction value defining the direction of the transfer
priority	A DMA_Priority_level value defining the priority of the transfer

Returns

A configured DMA channel handle pointer or NULL or error

stm32h7_dma_free()

void stm32h7_dma_free

(

DMA_HandleTypeDef *

dma_channel

)

Release a DMA channel.

This function tears down and releases a DMA channel allocated using stm32h7_dma_alloc().

Parameters

dma_channel

A DMA channel handle pointer