VE DMA is a DMA data transfer feature for VE programs. More...

Data Structures
struct	ve_dma_handle_t
	This structure holds the state of the asynchronous DMA. More...

Functions
int	ve_dma_init (void)
	This function initializes VE DMA feature. More...

int	ve_dma_post (uint64_t dst, uint64_t src, int size, ve_dma_handle_t *handle)
	This function issues asynchronous DMA. More...

int	ve_dma_poll (ve_dma_handle_t *handle)
	This function inquiries the completion of asynchronous DMA. More...

int	ve_dma_wait (ve_dma_handle_t *handle)
	This function iterates over the inquiry until it completes the asynchronous DMA,. More...

int	ve_dma_post_wait (uint64_t dst, uint64_t src, int size)
	This function issues synchronous DMA. More...

uint64_t	ve_register_mem_to_dmaatb (void *vemva, size_t size)
	This function registers VE local memory to DMAATB. More...

int	ve_unregister_mem_from_dmaatb (uint64_t vehva)
	This function unregisters VE local memory from DMAATB. More...

Variables
int	ve_dma_handle_t::status

int	ve_dma_handle_t::index

Detailed Description

VE DMA is a DMA data transfer feature for VE programs.

Please include "vedma.h" in the source file. Please specify "-lveio -pthread" option to the compiler driver to link libveio.

Note: A source and a destination of DMA data transfer are specified by VE host virtual address. To obtain VE host virtual address, you need to register memory to DMAATB.; A source and a destination of DMA data transfer needs to be aligned on a 4 byte boundary.; Data transfer size needs to be a multiple of 4 and less than 128MB.

Function Documentation

int ve_dma_init ( void )

This function initializes VE DMA feature.

Note: When the VE program invokes this function multiple times, this function simply returns 0.; Before using VE DMA, invoke this function to initialize VE DMA.
When a child process is created by fork(), vfork(), the state of VE DMA is not inherited to the child process. This function should be invoked from the child process.

Return values

0	On success
-1	On failure

Examples:: vedma/dma.c.

int ve_dma_post	(	uint64_t	dst,
		uint64_t	src,
		int	size,
		ve_dma_handle_t *	handle
	)

This function issues asynchronous DMA.

Note: This function writes the DMA transfer request to the DMA descriptor table.

Parameters

[in]	dst	4 byte aligned VE host virtual address of destination
[in]	src	4 byte aligned VE host virtual address of source
[in]	size	Transfer size which is a multiple of 4 and less than 128MB
[out]	handle	Handle used to inquire DMA completion

Return values

0	On success
-EAGAIN	The DMA using the DMA descriptor to be used next is not yet completed Need to call ve_dma_post() again.

int ve_dma_poll ( ve_dma_handle_t * handle )

This function inquiries the completion of asynchronous DMA.

Note: This function inquiries the completion of DMA transfer request issued by ve_dma_post().

Parameters

[in] handle DMA transfer request issued by ve_dma_post()

Return values

0	DMA completed normally
1-65535	DMA failed Exception value of DMA descriptor is returned. DMA failed. The value is bitwise ORed combination of the values described below. 0x8000: Memory protection exception 0x4000: Missing page exception 0x2000: Missing space exception 0x1000: Memory access exception 0x0800: I/O access exception
-EAGAIN	DMA has not completed yet Need to call ve_dma_poll() again

int ve_dma_wait ( ve_dma_handle_t * handle )

This function iterates over the inquiry until it completes the asynchronous DMA,.

Note: This function iterates over the inquiry the completion of DMA transfer request
issued by ve_dma_post(), until it completes the asynchronous DMA.

Parameters

[in] handle DMA transfer request issued by ve_dma_post()

Return values

0	DMA completed normally
1-65535	DMA failed Exception value of DMA descriptor is returned. DMA failed. The value is bitwise ORed combination of the values described below. 0x8000: Memory protection exception 0x4000: Missing page exception 0x2000: Missing space exception 0x1000: Memory access exception 0x0800: I/O access exception

int ve_dma_post_wait	(	uint64_t	dst,
		uint64_t	src,
		int	size
	)

This function issues synchronous DMA.

Note: This function writes the DMA transfer request to the DMA descriptor table, and waits for finish.

Parameters

[in]	dst	4 byte aligned VE host virtual address of destination
[in]	src	4 byte aligned VE host virtual address of source
[in]	size	Transfer size which is a multiple of 4 and less than 128MB

Return values

0	On success
1-65535	DMA failed Exception value of DMA descriptor is returned. DMA failed. The value is bitwise ORed combination of the values described below. 0x8000: Memory protection exception 0x4000: Missing page exception 0x2000: Missing space exception 0x1000: Memory access exception 0x0800: I/O access exception

Examples:: vedma/dma.c.

uint64_t ve_register_mem_to_dmaatb	(	void *	vemva,
		size_t	size
	)

This function registers VE local memory to DMAATB.

Note: The default value of VE page size is 64MB.
In this case, values of vemva and size need to be aligned with 64MB boundary.
If VE page size is 2MB, values of vemva and size need to be aligned with 2MB boundary.

Parameters

[in]	vemva	An address of memory to be registered The address needs to be aligned with 64MB boundary.
[in]	size	Size of memory aligned aligned with 64MB boundary

Return values

vehva	VE host virtual address on success
0xffffffffffffffff	On failure EINVAL Invalid argument EFAULT Bad address ESRCH No such process ENOENT No such memory EACCES Permission denied ECANCEL Operation canceled

Examples:: vedma/dma.c.

int ve_unregister_mem_from_dmaatb ( uint64_t vehva )

This function unregisters VE local memory from DMAATB.

Parameters

[in] vehva VE host virtual address of memory to be unregistered

Return values

0	On success
-1	On failure EINVAL Invalid argument ECANCELED No such memory

Examples:: vedma/dma.c.

Data Structures

Functions

Variables

Detailed Description

Function Documentation