rt_dma_controller_ops Struct Reference

#include <dma.h>

Data Fields
struct rt_dma_chan *(*	request_chan )(struct rt_dma_controller *ctrl, struct rt_device *slave, void *fw_data)
rt_err_t(*	release_chan )(struct rt_dma_chan *chan)
rt_err_t(*	start )(struct rt_dma_chan *chan)
rt_err_t(*	pause )(struct rt_dma_chan *chan)
rt_err_t(*	stop )(struct rt_dma_chan *chan)
rt_err_t(*	config )(struct rt_dma_chan *chan, struct rt_dma_slave_config *conf)
rt_err_t(*	prep_memcpy )(struct rt_dma_chan *chan, rt_ubase_t dma_addr_src, rt_ubase_t dma_addr_dst, rt_size_t len)
rt_err_t(*	prep_cyclic )(struct rt_dma_chan *chan, rt_ubase_t dma_buf_addr, rt_size_t buf_len, rt_size_t period_len, enum rt_dma_transfer_direction dir)
rt_err_t(*	prep_single )(struct rt_dma_chan *chan, rt_ubase_t dma_buf_addr, rt_size_t buf_len, enum rt_dma_transfer_direction dir)

Detailed Description

DMA controller operations vtable.

Each DMA controller driver provides implementations of these operations. start, stop, and config are mandatory; the rest are optional.

Field Documentation

request_chan

struct rt_dma_chan*(* rt_dma_controller_ops::request_chan) (struct rt_dma_controller *ctrl, struct rt_device *slave, void *fw_data)

Request a DMA channel (optional)

Parameters

[in]	ctrl	DMA controller
[in]	slave	Device requesting the channel
[in]	fw_data	Device tree cell args (NULL for mem-to-mem)

Returns

Channel pointer, RT_NULL, or error pointer

release_chan

rt_err_t(* rt_dma_controller_ops::release_chan) (struct rt_dma_chan *chan)

Release a DMA channel (optional)

Parameters

[in]

chan

Channel to release

Returns

RT_EOK on success

start

rt_err_t(* rt_dma_controller_ops::start) (struct rt_dma_chan *chan)

Start a prepared transfer (mandatory)

Parameters

[in]

chan

Channel with a successfully prepared transfer

Returns

RT_EOK on success

pause

rt_err_t(* rt_dma_controller_ops::pause) (struct rt_dma_chan *chan)

Pause a running transfer (optional)

If not implemented, the framework falls back to stop().

Parameters

[in]

chan

Channel to pause

Returns

RT_EOK on success

stop

rt_err_t(* rt_dma_controller_ops::stop) (struct rt_dma_chan *chan)

Stop a running transfer (mandatory)

Parameters

[in]

chan

Channel to stop

Returns

RT_EOK on success

config

rt_err_t(* rt_dma_controller_ops::config) (struct rt_dma_chan *chan, struct rt_dma_slave_config *conf)

Configure a DMA channel (mandatory)

Parameters

[in]	chan	Channel to configure
[in]	conf	Slave configuration

Returns

RT_EOK on success

prep_memcpy

rt_err_t(* rt_dma_controller_ops::prep_memcpy) (struct rt_dma_chan *chan, rt_ubase_t dma_addr_src, rt_ubase_t dma_addr_dst, rt_size_t len)

Prepare a memory-to-memory transfer (optional)

Parameters

[in]	chan	DMA channel
[in]	dma_addr_src	Source physical address
[in]	dma_addr_dst	Destination physical address
[in]	len	Transfer length in bytes

Returns

RT_EOK on success

prep_cyclic

rt_err_t(* rt_dma_controller_ops::prep_cyclic) (struct rt_dma_chan *chan, rt_ubase_t dma_buf_addr, rt_size_t buf_len, rt_size_t period_len, enum rt_dma_transfer_direction dir)

Prepare a cyclic (repeating) transfer (optional)

Parameters

[in]	chan	DMA channel
[in]	dma_buf_addr	Buffer physical address
[in]	buf_len	Total buffer length in bytes
[in]	period_len	Bytes per period (callback interval)
[in]	dir	Transfer direction

Returns

RT_EOK on success

prep_single

rt_err_t(* rt_dma_controller_ops::prep_single) (struct rt_dma_chan *chan, rt_ubase_t dma_buf_addr, rt_size_t buf_len, enum rt_dma_transfer_direction dir)

Prepare a single (one-shot) transfer (optional)

Parameters

[in]	chan	DMA channel
[in]	dma_buf_addr	Buffer physical address
[in]	buf_len	Transfer length in bytes
[in]	dir	Transfer direction

Returns

RT_EOK on success