joybus.c File Reference

Joybus Subsystem. More...

Data Structures
struct	joybus_msg_t
	A message to be sent to JoyBus, with its completion callback. More...

Macros
#define	MAX_JOYBUS_MSGS   8
	Maximum number of pending joybus messages.
SI status register bit definitions
#define	SI_STATUS_DMA_BUSY   ( 1 << 0 )
	SI DMA busy.
#define	SI_STATUS_IO_BUSY   ( 1 << 1 )
	SI IO busy.
Joybus internal state machine values
#define	JOYBUS_STATE_IDLE   0
	Joybus state: idle (no pending messages)
#define	JOYBUS_STATE_SENDING   1
	JoyBus state: sending a message to PIF.
#define	JOYBUS_STATE_RECEIVING   2
	JoyBus state: receiving a reply from PIF.

Functions
void	__joybus_init (void)
	Initialize the joybus subsystem.
void	joybus_exec_async (const void *input, void(*callback)(uint64_t *output, void *ctx), void *ctx)
	Execute an asynchronous joybus message. More...
void	joybus_exec (const void *input, void *output)
	Write a 64-byte block of data to the PIF and read the 64-byte result. More...

Detailed Description

Joybus Subsystem.

Function Documentation

joybus_exec_async()

void joybus_exec_async	(	const void *	input,
		void(*)(uint64_t *output, void *ctx)	callback,
		void *	ctx
	)

Execute an asynchronous joybus message.

This function executes an asynchronous joybus protocol exchange, sending a message block (input), and receiving a reply (output). The message is sent in background and a completion function "callback" is called when the output is ready to be processed.

It is possible to schedule multiple joybus messages by calling this function multiple times. They will be automatically executed in order. The maximum number of pending messages at any given time is MAX_JOYBUS_MSGS.

Note

The callback function will be called under interrupt.

This function is not part of the public API yet because we want to evaluate the use of threading rather than asynchronous programming. It should only be used internally without exposing a asynchronous API externally.

Parameters

[in]	input	The input block (must be of JOYBUS_BLOCK_SIZE bytes). No specific alignment is required for this data block.
[in]	callback	A callback completion function that will be called when the joybus command is finished. The function will receive a pointer to the output buffer and the opaque pointer to the callback's context. Can be NULL if no callback is required.
[in]	ctx	Context opaque pointer to pass to the callback. Can be NULL if no context is required.