dma.h File Reference

Explicit DMA memory domains, physical streams and drain facts. More...

#include "nexus/core/status.h"

Go to the source code of this file.

Data Structures
struct	nx_dma_memory_region_t
	Reviewed DMA-visible memory interval, never CPU accessibility. More...
struct	nx_dma_resource_t
	Opaque physical engine and request selector identities. More...
struct	nx_dma_drain_facts_t
	Independent facts required before memory borrow release. More...

Macros
#define	NX_DMA_MEMORY_READ   1U
#define	NX_DMA_MEMORY_WRITE   2U

Enumerations
enum	nx_dma_direction_t { NX_DMA_TO_DEVICE , NX_DMA_FROM_DEVICE }
	Transfer direction determines device access to caller memory. More...

Functions
nx_result_t	nx_dma_buffer_validate (const nx_dma_memory_region_t *regions, size_t count, const void *data, size_t length, size_t alignment, nx_dma_direction_t direction)
	Validate an entire buffer within one explicit memory domain.
nx_result_t	nx_dma_resources_validate (const nx_dma_resource_t *resources, size_t count)
	Reject duplicate physical streams in an assembled resource set.
nx_result_t	nx_dma_drain_check (const nx_dma_drain_facts_t *facts)
	Require engine, IRQ and peripheral drain independently.

Detailed Description

Explicit DMA memory domains, physical streams and drain facts.

Author

Nexus Team

Definition in file dma.h.

Macro Definition Documentation

NX_DMA_MEMORY_READ

#define NX_DMA_MEMORY_READ   1U

Definition at line 18 of file dma.h.

NX_DMA_MEMORY_WRITE

#define NX_DMA_MEMORY_WRITE   2U

Definition at line 19 of file dma.h.

Enumeration Type Documentation

nx_dma_direction_t

enum nx_dma_direction_t

Transfer direction determines device access to caller memory.

Enumerator
NX_DMA_TO_DEVICE
NX_DMA_FROM_DEVICE

Definition at line 22 of file dma.h.

Function Documentation

nx_dma_buffer_validate()

nx_result_t nx_dma_buffer_validate	(	const nx_dma_memory_region_t *	regions,
		size_t	count,
		const void *	data,
		size_t	length,
		size_t	alignment,
		nx_dma_direction_t	direction )

Validate an entire buffer within one explicit memory domain.

Parameters

[in]	regions	Immutable SoC domains kept alive for this call.
[in]	count	Positive number of domains.
[in]	data	Nonempty caller buffer; never borrowed by this helper.
[in]	length	Positive byte length, including all DMA accesses.
[in]	alignment	Nonzero power-of-two transfer alignment.
[in]	direction	Device reads or writes the supplied memory.

Returns

Success, INVALID for malformed ranges/alignment or PERMISSION for a range outside the required DMA domain.

Note

Bounded task/IRQ check, no MMIO, allocation or side effects.

nx_dma_drain_check()

nx_result_t nx_dma_drain_check

(

const nx_dma_drain_facts_t *

facts

)

Require engine, IRQ and peripheral drain independently.

Parameters

[in]

facts

Provider observations; not retained.

Returns

Success only when all sources are detached and idle, BUSY while any source remains, INVALID for impossible counters.

Note

The provider must observe actual registers and ordering before setting these facts. This helper does not stop hardware.

nx_dma_resources_validate()

nx_result_t nx_dma_resources_validate	(	const nx_dma_resource_t *	resources,
		size_t	count )

Reject duplicate physical streams in an assembled resource set.

Parameters

[in]	resources	Immutable resource list, not retained.
[in]	count	Resource count; zero allows a NULL list.

Returns

Success, INVALID for a NULL nonempty list or reserved zero controller, BUSY for a duplicate physical engine.

Note

Cold conflict check; the selected SoC must validate all identities against its actual topology before using them. This helper does not infer silicon support or allocate.