Overview

This section describes the programming interface of the DMA Peripheral driver. The DMA driver requests, configures, and uses the DMA hardware. It supports module initialization and DMA channel configuration.

Data Structures
struct	dma_channel_t
	Data structure for the DMA channel management. More...

struct	dma_state_t
	Data structure for the DMA controller management. More...

Typedefs
typedef void(*	dma_callback_t )(void *parameter, dma_channel_status_t status)
	A definition for the DMA channel callback function. More...

Enumerations
enum	dma_channel_status_t { kDmaIdle, kDmaNormal, kDmaError }
	Channel status for the DMA channel. More...

enum	dma_channel_type_t { kDmaInvalidChannel = 0xFFU, kDmaAnyChannel = 0xFEU }
	Type for the DMA channel, which is used for the DMA channel allocation. More...

Variables
DMA_Type *const	g_dmaBase [DMA_INSTANCE_COUNT]
	Array for eDMA module register base address. More...

DMAMUX_Type *const	g_dmamuxBase [DMAMUX_INSTANCE_COUNT]
	Array for DMAMUX module register base address. More...

const IRQn_Type	g_dmaIrqId [DMA_INSTANCE_COUNT][FSL_FEATURE_DMA_DMAMUX_CHANNELS]
	Two-dimensional array for eDMA channel interrupt vector number. More...

DMA Driver
dma_status_t	DMA_DRV_Init (dma_state_t *state)
	Initializes the DMA. More...

dma_status_t	DMA_DRV_Deinit (void)
	De-initializes the DMA. More...

dma_status_t	DMA_DRV_SetDestTransferSize (dma_channel_t *chn, uint32_t transferSize)
	Updates the DMA destination transfer size. More...

dma_status_t	DMA_DRV_SetSourceTransferSize (dma_channel_t *chn, uint32_t transferSize)
	Updates the DMA source transfer size. More...

dma_status_t	DMA_DRV_RegisterCallback (dma_channel_t chn, dma_callback_t callback, void para)
	Registers the callback function and a parameter. More...

uint32_t	DMA_DRV_GetUnfinishedBytes (dma_channel_t *chn)
	Gets the number of unfinished bytes. More...

dma_status_t	DMA_DRV_ClaimChannel (uint32_t channel, dma_request_source_t source, dma_channel_t *chn)
	Claims a DMA channel. More...

uint32_t	DMA_DRV_RequestChannel (uint32_t channel, dma_request_source_t source, dma_channel_t *chn)
	Requests a DMA channel. More...

dma_status_t	DMA_DRV_FreeChannel (dma_channel_t *chn)
	Frees DMA channel hardware and software resource. More...

dma_status_t	DMA_DRV_StartChannel (dma_channel_t *chn)
	Starts a DMA channel. More...

dma_status_t	DMA_DRV_StopChannel (dma_channel_t *chn)
	Stops a DMA channel. More...

dma_status_t	DMA_DRV_ConfigTransfer (dma_channel_t *chn, dma_transfer_type_t type, uint32_t size, uint32_t sourceAddr, uint32_t destAddr, uint32_t length)
	Configures a transfer for the DMA. More...

dma_status_t	DMA_DRV_ConfigChanLink (dma_channel_t chn, dma_channel_link_config_t link_config)
	Configures the channel link feature. More...

void	DMA_DRV_IRQhandler (uint32_t channel)
	DMA IRQ handler for both an interrupt and an error. More...

Data Structure Documentation

struct dma_channel_t

Data Fields
uint8_t	channel
	Channel number.

uint8_t	dmamuxModule
	DMAMUX module index.

uint8_t	dmamuxChannel
	DMAMUX module channel.

dma_callback_t	callback
	Callback function for this channel.

void *	parameter
	Parameter for the callback function.

volatile dma_channel_status_t	status
	Channel status.

struct dma_state_t

Typedef Documentation

typedef void(* dma_callback_t)(void *parameter, dma_channel_status_t status)

A prototype for the callback function registered into the DMA driver.

Enumeration Type Documentation

enum dma_channel_status_t

A structure describing the status of the DMA channel. The user can get the status from the channel callback function.

Enumerator
kDmaIdle	DMA channel is idle.
kDmaNormal	DMA channel is occupied.
kDmaError	Error occurs in the DMA channel.

enum dma_channel_type_t

Enumerator

kDmaInvalidChannel

Macros indicating the failure of the channel request.

kDmaAnyChannel

Macros used when requesting a channel.

kEdmaAnyChannel means a request of dynamic channel allocation.

Function Documentation

dma_status_t DMA_DRV_Init ( dma_state_t * state )

Parameters

state DMA state structure used for the DMA internal logic.

Returns: If successful, returns the kStatus_DMA_Success. Otherwise, it returns an error.

dma_status_t DMA_DRV_Deinit ( void )

Returns: If successful, returns the kStatus_DMA_Success. Otherwise, it returns an error.

dma_status_t DMA_DRV_SetDestTransferSize	(	dma_channel_t *	chn,
		uint32_t	transferSize
	)

Parameters

chn	A handler for the DMA channel
transferSize	Size of destination at each transfer

Returns: If successful, returns the kStatus_DMA_Success. Otherwise, it returns an error.

dma_status_t DMA_DRV_SetSourceTransferSize	(	dma_channel_t *	chn,
		uint32_t	transferSize
	)

Parameters

chn	A handler for the DMA channel
transferSize	Size of source at each transfer

Returns: If successful, returns the kStatus_DMA_Success. Otherwise, it returns an error.

dma_status_t DMA_DRV_RegisterCallback	(	dma_channel_t *	chn,
		dma_callback_t	callback,
		void *	para
	)

The user registers the callback function and a parameter for a specified DMA channel. When the channel interrupt or a channel error happens, the callback and the parameter are called. The user parameter is also provided to give a channel status.

Parameters

chn	A handler for the DMA channel
callback	Callback function
para	A parameter for callback functions

Returns: If successful, returns the kStatus_DMA_Success. Otherwise, it returns an error.

uint32_t DMA_DRV_GetUnfinishedBytes ( dma_channel_t * chn )

Gets the bytes that remain to be transferred.

Parameters

chn	A handler for the DMA channel

Returns: If successful, returns the kStatus_DMA_Success. Otherwise, it returns an error.

dma_status_t DMA_DRV_ClaimChannel	(	uint32_t	channel,
		dma_request_source_t	source,
		dma_channel_t *	chn
	)

Parameters

channel	Channel index which needs to claim.
source	DMA request source.
chn	A handler for the DMA channel

Returns: If successful, returns the kStatus_DMA_Success. Otherwise, it returns an error.

uint32_t DMA_DRV_RequestChannel	(	uint32_t	channel,
		dma_request_source_t	source,
		dma_channel_t *	chn
	)

This function provides two ways to allocate a DMA channel: static and dynamic allocation. To allocate a channel dynamically, set the channel parameter with the value of kDmaAnyChannel. The driver searches all available free channels and assigns the first channel to the user. To allocate the channel statically, set the channel parameter with the value of a specified channel. If the channel is available, the driver assigns the channel. Notes: The user must provide a handler memory for the DMA channel. The driver initializes the handler and configures the handler memory.

Parameters

channel	A DMA channel number. If a channel is assigned with a valid channel number, the DMA driver tries to assign a specified channel. If a channel is assigned with kDmaAnyChannel, the DMA driver searches all available channels and assigns the first channel to the user.
source	A DMA hardware request.
chn	Memory pointing to DMA channel. The user must ensure that the handler memory is valid and that it will not be released or changed by any other code before the channel dma_free_channel() operation.

Returns: If the channel allocation is successful, the return value indicates the requested channel. If not, the driver returns a kDmaInvalidChannel value to indicate that the request operation has failed.

dma_status_t DMA_DRV_FreeChannel ( dma_channel_t * chn )

This function frees the relevant software and hardware resources. Both the request and the free operations need to be called as a pair.

Parameters

chn	Memory pointing to DMA channel.

Returns: If successful, returns the kStatus_DMA_Success. Otherwise, it returns an error.

dma_status_t DMA_DRV_StartChannel ( dma_channel_t * chn )

Starts a DMA channel. The driver starts a DMA channel by enabling the DMA request. A software start bit is not used in the DMA Peripheral driver.

Parameters

chn	Memory pointing to the DMA channel.

Returns: If successful, returns the kStatus_DMA_Success. Otherwise, it returns an error.

dma_status_t DMA_DRV_StopChannel ( dma_channel_t * chn )

Parameters

chn	Memory pointing to the DMA channel.

Returns: If successful, returns the kStatus_DMA_Success. Otherwise, it returns an error.

dma_status_t DMA_DRV_ConfigTransfer	(	dma_channel_t *	chn,
		dma_transfer_type_t	type,
		uint32_t	size,
		uint32_t	sourceAddr,
		uint32_t	destAddr,
		uint32_t	length
	)

Configures a transfer for the DMA.

Parameters

chn	Memory pointing to the DMA channel.
type	Transfer type.
size	Size to be transferred on each DMA write/read. Source/Dest share the same write/read size.
sourceAddr	Source address.
destAddr	Destination address.
length	Bytes to be transferred.

Returns: If successful, returns the kStatus_DMA_Success. Otherwise, it returns an error.

dma_status_t DMA_DRV_ConfigChanLink	(	dma_channel_t *	chn,
		dma_channel_link_config_t *	link_config
	)

Parameters

chn	Memory pointing to the DMA channel.
link_config	Configure of channel link in DMA.

Returns: If successful, returns the kStatus_DMA_Success. Otherwise, it returns an error.

void DMA_DRV_IRQhandler ( uint32_t channel )

Parameters

channel DMA channel number.

Variable Documentation

DMA_Type* const g_dmaBase[DMA_INSTANCE_COUNT]

DMAMUX_Type* const g_dmamuxBase[DMAMUX_INSTANCE_COUNT]

const IRQn_Type g_dmaIrqId[DMA_INSTANCE_COUNT][FSL_FEATURE_DMA_DMAMUX_CHANNELS]

Overview

Data Structures

Typedefs

Enumerations

Variables

DMA Driver

Data Structure Documentation

Data Fields

Typedef Documentation

Enumeration Type Documentation

Function Documentation

Variable Documentation