dma.h File Reference

DMA helpers. More...

Macros
#define	REG_DMA_CH_CONTROL   (*(vu16 *)0x81DE)
	DMA Channel: Start/Stop/Control (R/W)
#define	REG_DMA_CH_DIM0_DST_STEP   (*(vs16 *)0x81D0)
	DMA Channel: Source Step1 (signed) (R/W)
#define	REG_DMA_CH_DIM0_LEN   (*(vu16 *)0x81C8)
	DMA Channel: Size0 (inner dimension) (R/W)
#define	REG_DMA_CH_DIM0_SRC_STEP   (*(vs16 *)0x81CE)
	DMA Channel: Source Step0 (signed) (R/W)
#define	REG_DMA_CH_DIM1_DST_STEP   (*(vs16 *)0x81D4)
	DMA Channel: Destination Step0 (signed) (R/W)
#define	REG_DMA_CH_DIM1_LEN   (*(vu16 *)0x81CA)
	DMA Channel: Size1 (middle dimension) (R/W)
#define	REG_DMA_CH_DIM1_SRC_STEP   (*(vs16 *)0x81D2)
	DMA Channel: Source Step2 (signed) (R/W)
#define	REG_DMA_CH_DIM2_DST_STEP   (*(vs16 *)0x81D8)
	DMA Channel: Destination Step2 (signed) (R/W)
#define	REG_DMA_CH_DIM2_LEN   (*(vu16 *)0x81CC)
	DMA Channel: Size2 (outer dimension) (R/W)
#define	REG_DMA_CH_DIM2_SRC_STEP   (*(vs16 *)0x81D6)
	DMA Channel: Destination Step1 (signed) (R/W)
#define	REG_DMA_CH_DST_HI   (*(vu16 *)0x81C6)
	DMA Channel: Destination Address, bit16-31 (R/W)
#define	REG_DMA_CH_DST_LO   (*(vu16 *)0x81C4)
	DMA Channel: Destination Address, bit0-15 (R/W)
#define	REG_DMA_CH_SRC_HI   (*(vu16 *)0x81C2)
	DMA Channel: Source Address, bit16-31 (R/W)
#define	REG_DMA_CH_UNK_81DC   (*(vu16 *)0x81DC)
	DMA Channel: Unknown (R/W)
#define	REG_DMA_CH_XFER_CONFIG   (*(vu16 *)0x81DA)
	DMA Channel: Memory Area Config (R/W)
#define	REG_DMA_CHANNEL_SEL   (*(vu16 *)0x81BE)
	DMA Select Channel (0 to 7) (R/W)
#define	REG_DMA_DIM0_END   (*(vu16 *)0x8188)
	DMA Channel End Flags for Size0 (R)
#define	REG_DMA_DIM1_END   (*(vu16 *)0x818A)
	DMA Channel End Flags for Size1 (R)
#define	REG_DMA_DIM2_END   (*(vu16 *)0x818C)
	DMA Channel End Flags for Size2 (R) (all done)
#define	REG_DMA_PAUSE   (*(vu16 *)0x8186)
	DMA Channel Pause Flags (R/W)
#define	REG_DMA_START   (*(vu16 *)0x8184)
	DMA Channel Start Flags (R/W)

Functions
void	dmaInit (void)
	Initializes the DMA system.
s16	dmaTransferArm9ToDsp (u16 dma_channel, u32 src, void *dst, u16 len)
	Transfer data from the ARM9 memory map to the DSP data memory. More...
s16	dmaTransferArm9ToDspAsync (u16 dma_channel, u32 src, void *dst, u16 len)
	Starts a transfer of data from the ARM9 memory map to the DSP data memory. More...
s16	dmaTransferDspToArm9 (u16 dma_channel, const void *src, u32 dst, u16 len)
	Transfer data from DSP data memory to the ARM9 memory map. More...
s16	dmaTransferDspToArm9Async (u16 dma_channel, const void *src, u32 dst, u16 len)
	Starts a transfer of data from DSP data memory to the ARM9 memory map. More...
static u16	dmaTransferIsRunning (u16 dma_channel)
	Checks whether a DMA channel is active or not. More...
static void	dmaTransferWaitDone (u16 dma_channel)
	Waits until a DMA channel is no longer active because the copy has finished. More...

Detailed Description

DMA helpers.

The DMA registers don't seem to be understood well enough, the functions may be unstable.

• ARM9 to DSP transfers use AHBM channel 1.
• DSP to ARM9 transfers use AHBM channel 2.

Function Documentation

dmaTransferArm9ToDsp()

s16 dmaTransferArm9ToDsp	(	u16	dma_channel,
		u32	src,
		void *	dst,
		u16	len
	)

Transfer data from the ARM9 memory map to the DSP data memory.

This function uses AHBM channel 1.

DMA channel 0 is required to transfer data with the FIFO functions, so it can't be used by this function.

This function can't copy data crossing a 1KB boundary on the ARM9 side because of limitations of the AHBM bus.

Parameters

dma_channel	The DMA channel to use (1 to 7, 0 isn't allowed).
src	Source address in the ARM9 memory map.
dst	Destination address in the DSP data memory.
len	Length of the copy in DSP words.

Returns

It returns 0 on success, other values on error.

dmaTransferArm9ToDspAsync()

s16 dmaTransferArm9ToDspAsync	(	u16	dma_channel,
		u32	src,
		void *	dst,
		u16	len
	)

Starts a transfer of data from the ARM9 memory map to the DSP data memory.

This function uses AHBM channel 1.

DMA channel 0 is required to transfer data with the FIFO functions, so it can't be used by this function.

This function can't copy data crossing a 1KB boundary on the ARM9 side because of limitations of the AHBM bus.

Use dmaTransferIsRunning() to verify if the transfer has finished or not, or dmaTransferWaitDone() to wait until it's done.

Parameters

dma_channel	The DMA channel to use (1 to 7, 0 isn't allowed).
src	Source address in the ARM9 memory map.
dst	Destination address in the DSP data memory.
len	Length of the copy in DSP words.

Returns

It returns 0 on success, other values on error.

dmaTransferDspToArm9()

s16 dmaTransferDspToArm9	(	u16	dma_channel,
		const void *	src,
		u32	dst,
		u16	len
	)

Transfer data from DSP data memory to the ARM9 memory map.

This function uses AHBM channel 2.

DMA channel 0 is required to transfer data with the FIFO functions, so it can't be used by this function.

This function can't copy data crossing a 1KB boundary on the ARM9 side because of limitations of the AHBM bus.

Parameters

dma_channel	The DMA channel to use (1 to 7, 0 isn't allowed).
src	Source address in the DSP data memory.
dst	Destination address in the ARM9 memory map.
len	Length of the copy in DSP words.

Returns

It returns 0 on success, other values on error.

dmaTransferDspToArm9Async()

s16 dmaTransferDspToArm9Async	(	u16	dma_channel,
		const void *	src,
		u32	dst,
		u16	len
	)

Starts a transfer of data from DSP data memory to the ARM9 memory map.

This function uses AHBM channel 2.

DMA channel 0 is required to transfer data with the FIFO functions, so it can't be used by this function.

This function can't copy data crossing a 1KB boundary on the ARM9 side because of limitations of the AHBM bus.

Use dmaTransferIsRunning() to verify if the transfer has finished or not, or dmaTransferWaitDone() to wait until it's done.

Parameters

dma_channel	The DMA channel to use (1 to 7, 0 isn't allowed).
src	Source address in the DSP data memory.
dst	Destination address in the ARM9 memory map.
len	Length of the copy in DSP words.

Returns

It returns 0 on success, other values on error.

dmaTransferIsRunning()

static u16 dmaTransferIsRunning ( u16  dma_channel )

inlinestatic

Checks whether a DMA channel is active or not.

Parameters

dma_channel

The DMA channel to check (1 to 7, 0 isn't allowed).

Returns

It returns 1 if the DMA channel is busy, 0 if not.

dmaTransferWaitDone()

static void dmaTransferWaitDone ( u16  dma_channel )

inlinestatic

Waits until a DMA channel is no longer active because the copy has finished.

Parameters

dma_channel

The DMA channel to check (1 to 7, 0 isn't allowed).