Managed mempak interface. More...

Files
file	mempak.c
	Mempak Filesystem Routine.

file	mempak.h
	Mempak Filesystem Routines.

Data Structures
struct	entry_structure_t
	Structure representing a save entry in a mempak. More...

Macros
#define	MEMPAK_BLOCK_SIZE 256
	Size in bytes of a Mempak block.

Functions
int	read_mempak_sector (int controller, int sector, uint8_t *sector_data)
	Read a sector from a mempak. More...

int	write_mempak_sector (int controller, int sector, uint8_t *sector_data)
	Write a sector to a mempak. More...

int	validate_mempak (int controller)
	Return whether a mempak is valid. More...

int	get_mempak_entry (int controller, int entry, entry_structure_t *entry_data)
	Read an entry on a mempak. More...

int	get_mempak_free_space (int controller)
	Return the number of free blocks on a mempak. More...

int	format_mempak (int controller)
	Format a mempak. More...

int	read_mempak_entry_data (int controller, entry_structure_t entry, uint8_t data)
	Read the data associated with an entry on a mempak. More...

int	write_mempak_entry_data (int controller, entry_structure_t entry, uint8_t data)
	Write associated data to a mempak entry. More...

int	delete_mempak_entry (int controller, entry_structure_t *entry)
	Delete a mempak entry and associated data. More...

Inode values
#define	BLOCK_EMPTY 0x03
	This block is empty.

#define	BLOCK_LAST 0x01
	This is the last block in the note.

#define	BLOCK_VALID_FIRST 0x05
	First valid block that can contain user data.

#define	BLOCK_VALID_LAST 0x7F
	Last valid block that can contain user data.

Detailed Description

Managed mempak interface.

The mempak system is a subsystem of the Controller Subsystem. Before attempting to read from or write to a mempak, be sure you have initialized the controller system with controller_init and verified that you have a mempak in the correct controller using identify_accessory.

To read and write to the mempak in an organized way compatible with official software, first check that the mempak is valid using validate_mempak. If the mempack is invalid, it will need to be formatted using format_mempak. Once the mempak is considered valid, existing notes can be enumerated using get_mempak_entry. To read the data associated with a note, use read_mempak_entry_data. To write a new note to the mempak, use write_mempak_entry_data. Note that there is no append functionality so if a note is being updated, ensure you have deleted the old note first using delete_mempak_entry. Code should be careful to check how many blocks are free before writing using get_mempak_free_space.

Data Structure Documentation

◆ entry_structure_t

struct entry_structure_t

Structure representing a save entry in a mempak.

Data Fields
uint32_t	vendor	Vendor ID.
uint16_t	game_id	Game ID.
uint16_t	inode	Inode pointer.
uint8_t	region	Intended region.
uint8_t	blocks	Number of blocks used by this entry. See also MEMPAK_BLOCK_SIZE
uint8_t	valid	Validity of this entry.
uint8_t	entry_id	ID of this entry.
char	name[19]	Name of this entry. The complete list of valid ASCII characters in a note name is: ABCDEFGHIJKLMNOPQRSTUVWXYZ!"#`*+,-./:=?@ The space character is also allowed. Any other character will be converted to a space before writing to the mempak.

Function Documentation

◆ read_mempak_sector()

int read_mempak_sector	(	int	controller,
		int	sector,
		uint8_t *	sector_data
	)

Read a sector from a mempak.

This will read a sector from a mempak. Sectors on mempaks are always 256 bytes in size.

Parameters

[in]	controller	The controller (0-3) to read a sector from
[in]	sector	The sector (0-127) to read from
[out]	sector_data	Buffer to place 256 read bytes of data

Return values

0	if reading was successful
-1	if the sector was out of bounds or sector_data was null
-2	if there was an error reading part of a sector

◆ write_mempak_sector()

int write_mempak_sector	(	int	controller,
		int	sector,
		uint8_t *	sector_data
	)

Write a sector to a mempak.

This will write a sector to a mempak. Sectors on mempaks are always 256 bytes in size.

Parameters

[in]	controller	The controller (0-3) to write a sector to
[in]	sector	The sector (0-127) to write to
[out]	sector_data	Buffer containing 256 bytes of data to write to sector

Return values

0	if writing was successful
-1	if the sector was out of bounds or sector_data was null
-2	if there was an error writing part of a sector

◆ validate_mempak()

int validate_mempak ( int controller )

Return whether a mempak is valid.

This function will return whether the mempak in a particular controller is formatted and valid.

Parameters

[in] controller The controller (0-3) to validate

Return values

0	if the mempak is valid and ready to be used
-2	if the mempak is not present or couldn't be read
-3	if the mempak is bad or unformatted

◆ get_mempak_entry()

int get_mempak_entry	(	int	controller,
		int	entry,
		entry_structure_t *	entry_data
	)

Read an entry on a mempak.

Given an entry index (0-15), return the entry as found on the mempak. If the entry is blank or invalid, the valid flag is cleared.

Parameters

[in]	controller	The controller (0-3) from which the entry should be read
[in]	entry	The entry index (0-15) to read
[out]	entry_data	Structure containing information on the entry

Return values

0	if the entry was read successfully
-1	if the entry is out of bounds or entry_data is null
-2	if the mempak is bad or not present

◆ get_mempak_free_space()

int get_mempak_free_space ( int controller )

Return the number of free blocks on a mempak.

Note that a block is identical in size to a sector. To calculate the number of bytes free, multiply the return of this function by MEMPAK_BLOCK_SIZE.

Parameters

[in] controller The controller (0-3) to read the free space from

Returns: The number of blocks free on the memory card or a negative number on failure

◆ format_mempak()

int format_mempak ( int controller )

Format a mempak.

Formats a mempak. Should only be done to wipe a mempak or to initialize the filesystem in case of a blank or corrupt mempak.

Parameters

[in] controller The controller (0-3) to format the mempak on

Return values

0	if the mempak was formatted successfully
-2	if the mempak was not present or couldn't be formatted

◆ read_mempak_entry_data()

int read_mempak_entry_data	(	int	controller,
		entry_structure_t *	entry,
		uint8_t *	data
	)

Read the data associated with an entry on a mempak.

Given a valid mempak entry fetched by get_mempak_entry, retrieves the contents of the entry. The calling function must ensure that enough room is available in the passed in buffer for the entire entry. The entry structure itself contains the number of blocks used to store the data which can be multiplied by MEMPAK_BLOCK_SIZE to calculate the size of the buffer needed.

Parameters

[in]	controller	The controller (0-3) to read the entry data from
[in]	entry	The entry structure associated with the data to be read. An entry structure can be fetched based on index using get_mempak_entry
[out]	data	The data associated with an entry

Return values

0	if the entry was successfully read
-1	if input parameters were out of bounds or the entry was corrupted somehow
-2	if the mempak was not present or bad
-3	if the data couldn't be read

◆ write_mempak_entry_data()

int write_mempak_entry_data	(	int	controller,
		entry_structure_t *	entry,
		uint8_t *	data
	)

Write associated data to a mempak entry.

Given a mempak entry structure with a valid region, name and block count, writes the entry and associated data to the mempak. This function will not overwrite any existing user data. To update an existing entry, use delete_mempak_entry followed by write_mempak_entry_data with the same entry structure.

Parameters

[in]	controller	The controller (0-3) to write the entry and data to
[in]	entry	The entry structure containing a region, name and block count
[in]	data	The associated data to write to to the created entry

Return values

0	if the entry was created and written successfully
-1	if the parameters were invalid or the note has no length
-2	if the mempak wasn't present or was bad
-3	if there was an error writing to the mempak
-4	if there wasn't enough space to store the note
-5	if there is no room in the TOC to add a new entry

◆ delete_mempak_entry()

int delete_mempak_entry	(	int	controller,
		entry_structure_t *	entry
	)

Delete a mempak entry and associated data.

Given a valid mempak entry fetched by get_mempak_entry, removes the entry and frees all associated blocks.

Parameters

[in]	controller	The controller (0-3) to delete the note from
[in]	entry	The entry structure that is to be deleted from the mempak

Return values

0	if the entry was deleted successfully
-1	if the entry was invalid
-2	if the mempak was bad or not present

Files

Data Structures

Macros

Functions

Inode values

Detailed Description

Data Structure Documentation

◆ entry_structure_t

Function Documentation

◆ read_mempak_sector()

◆ write_mempak_sector()

◆ validate_mempak()

◆ get_mempak_entry()

◆ get_mempak_free_space()

◆ format_mempak()

◆ read_mempak_entry_data()

◆ write_mempak_entry_data()

◆ delete_mempak_entry()