G2 bus memory interface. More...

#include <sys/cdefs.h>
#include <arch/types.h>

Macros
#define	SPU_DMA_MODE
#define	SPU_DMA_G2CHN 0
#define	SPU_DMA_SHCHN 3
#define	BBA_DMA_MODE 4
#define	BBA_DMA_G2CHN 1
#define	BBA_DMA_SHCHN 1
#define	BBA_DMA2_MODE 3
#define	BBA_DMA2_G2CHN 2
#define	BBA_DMA2_SHCHN 0

Typedefs
typedef void(*	g2_dma_callback_t )(ptr_t data)

Functions
int	g2_dma_transfer (void from, void dest, uint32 length, int block, g2_dma_callback_t callback, ptr_t cbdata, uint32 dir, uint32 mode, uint32 g2chn, uint32 sh4chn)
uint8	g2_read_8 (uint32 address)
	Read one byte from G2.
void	g2_write_8 (uint32 address, uint8 value)
	Write a single byte to G2.
uint16	g2_read_16 (uint32 address)
	Read one 16-bit word from G2.
void	g2_write_16 (uint32 address, uint16 value)
	Write a 16-bit word to G2.
uint32	g2_read_32 (uint32 address)
	Read one 32-bit dword from G2.
void	g2_write_32 (uint32 address, uint32 value)
	Write a 32-bit dword to G2.
void	g2_read_block_8 (uint8 *output, uint32 address, int amt)
	Read a block of bytes from G2.
void	g2_write_block_8 (const uint8 *input, uint32 address, int amt)
	Write a block of bytes to G2.
void	g2_read_block_16 (uint16 *output, uint32 address, int amt)
	Read a block of words from G2.
void	g2_write_block_16 (const uint16 *input, uint32 address, int amt)
	Write a block of words to G2.
void	g2_read_block_32 (uint32 *output, uint32 address, int amt)
	Read a block of dwords from G2.
void	g2_write_block_32 (const uint32 *input, uint32 address, int amt)
	Write a block of dwords to G2.
void	g2_memset_8 (uint32 address, uint8 c, int amt)
	Set a block of bytes to G2.
void	g2_fifo_wait ()
	Wait for the G2 write FIFO to empty.

Detailed Description

G2 bus memory interface.

This file provides low-level support for accessing devices on the G2 bus in the Dreamcast. The G2 bus contains the AICA, as well as the expansion port. Generally, you won't be dealing with things at this level, but rather on the level of the device you're actually interested in working with. Most of the expansion port devices (the modem, bba, and lan adapter) all have their own drivers that work off of this functionality.

The G2 bus is notoroiously picky about a lot of things. You have to be careful to use the right access size for whatever you're working with. Also you can't be doing PIO and DMA at the same time. Finally, there's a FIFO to contend with when you're doing PIO stuff as well. Generally, G2 is a pain in the rear, so you really do want to be using the higher-level stuff related to each device if at all possible!

Author:: Dan Potter

Macro Definition Documentation

#define BBA_DMA2_G2CHN 2

#define BBA_DMA2_MODE 3

#define BBA_DMA2_SHCHN 0

#define BBA_DMA_G2CHN 1

#define BBA_DMA_MODE 4

#define BBA_DMA_SHCHN 1

#define SPU_DMA_G2CHN 0

#define SPU_DMA_MODE

Value:

6 /* should we use 6 instead, so that the formula is 3+shchn ?

6 works too, so ... */

#define SPU_DMA_SHCHN 3

Typedef Documentation

typedef void(* g2_dma_callback_t)(ptr_t data)

Function Documentation

int g2_dma_transfer	(	void *	from,
		void *	dest,
		uint32	length,
		int	block,
		g2_dma_callback_t	callback,
		ptr_t	cbdata,
		uint32	dir,
		uint32	mode,
		uint32	g2chn,
		uint32	sh4chn
	)

void g2_fifo_wait ( )

Wait for the G2 write FIFO to empty.

This function will spinwait until the G2 FIFO indicates that it has been drained. The FIFO is 32 bytes in length, and thus when accessing AICA you must do this at least for every 8 32-bit writes that you execute.

void g2_memset_8	(	uint32	address,
		uint8	c,
		int	amt
	)

Set a block of bytes to G2.

This function acts as memset() for setting a block of bytes on G2. It will take the necessary precautions for accessing G2.

Parameters:

address	The address in G2-space to write to.
c	The byte to write.
amt	The number of bytes to write.

uint16 g2_read_16 ( uint32 address )

Read one 16-bit word from G2.

This function reads a single word from the specified address, taking all necessary precautions that are required for accessing G2.

Parameters:

address The address in memory to read.

Returns:: The word read from the address specified.

uint32 g2_read_32 ( uint32 address )

Read one 32-bit dword from G2.

This function reads a single dword from the specified address, taking all necessary precautions that are required for accessing G2.

Parameters:

address The address in memory to read.

Returns:: The dword read from the address specified.

uint8 g2_read_8 ( uint32 address )

Read one byte from G2.

This function reads a single byte from the specified address, taking all necessary precautions that are required for accessing G2.

Parameters:

address The address in memory to read.

Returns:: The byte read from the address specified.

void g2_read_block_16	(	uint16 *	output,
		uint32	address,
		int	amt
	)

Read a block of words from G2.

This function acts as memcpy() for copying data from G2 to system memory, but it copies 16 bits at a time. It will take the necessary precautions before accessing G2 for you as well.

Parameters:

output	Pointer in system memory to write to.
address	The address in G2-space to read from.
amt	The number of words to read.

void g2_read_block_32	(	uint32 *	output,
		uint32	address,
		int	amt
	)

Read a block of dwords from G2.

This function acts as memcpy() for copying data from G2 to system memory, but it copies 32 bits at a time. It will take the necessary precautions before accessing G2 for you as well.

Parameters:

output	Pointer in system memory to write to.
address	The address in G2-space to read from.
amt	The number of dwords to read.

void g2_read_block_8	(	uint8 *	output,
		uint32	address,
		int	amt
	)

Read a block of bytes from G2.

This function acts as memcpy() for copying data from G2 to system memory. It will take the necessary precautions before accessing G2 for you as well.

Parameters:

output	Pointer in system memory to write to.
address	The address in G2-space to read from.
amt	The number of bytes to read.

void g2_write_16	(	uint32	address,
		uint16	value
	)

Write a 16-bit word to G2.

This function writes one word to the specified address, taking all the necessary precautions to ensure your write actually succeeds.

Parameters:

address	The address in memory to write to.
value	The value to write to that address.

void g2_write_32	(	uint32	address,
		uint32	value
	)

Write a 32-bit dword to G2.

This function writes one dword to the specified address, taking all the necessary precautions to ensure your write actually succeeds.

Parameters:

address	The address in memory to write to.
value	The value to write to that address.

void g2_write_8	(	uint32	address,
		uint8	value
	)

Write a single byte to G2.

This function writes one byte to the specified address, taking all the necessary precautions to ensure your write actually succeeds.

Parameters:

address	The address in memory to write to.
value	The value to write to that address.

void g2_write_block_16	(	const uint16 *	input,
		uint32	address,
		int	amt
	)

Write a block of words to G2.

This function acts as memcpy() for copying data to G2 from system memory, copying 16 bits at a time. It will take the necessary precautions for accessing G2.

Parameters:

input	The pointer in system memory to read from.
address	The address in G2-space to write to.
amt	The number of words to write.

void g2_write_block_32	(	const uint32 *	input,
		uint32	address,
		int	amt
	)

Write a block of dwords to G2.

This function acts as memcpy() for copying data to G2 from system memory, copying 32 bits at a time. It will take the necessary precautions for accessing G2.

Parameters:

input	The pointer in system memory to read from.
address	The address in G2-space to write to.
amt	The number of dwords to write.

void g2_write_block_8	(	const uint8 *	input,
		uint32	address,
		int	amt
	)

Write a block of bytes to G2.

This function acts as memcpy() for copying data to G2 from system memory. It will take the necessary precautions for accessing G2.

Parameters:

input	The pointer in system memory to read from.
address	The address in G2-space to write to.
amt	The number of bytes to write.

Macros

Typedefs

Functions

Detailed Description

Macro Definition Documentation

Typedef Documentation

Function Documentation