Tiny Simple File System (TSFS), block device based

Data Structures
struct	tsfs_file
	Holds information about a specific file within a file system. More...
struct	tsfs_header
	Header structure. Holds generic information about the file system. More...
struct	tsfs_read_request
	Holds current read request being processed by a file system. More...
struct	tsfs_filetable_entry
	Holds information on one file in the file table. More...
struct	tsfs
	Holds information on a TSFS instance. More...
Defines
#define	TSFS_ID 0x17c1
	Unique ID to identify TSFS.
#define	TSFS_FILENAME_LEN 8
	Max characters in a filename.
#define	TSFS_MAX_FILES 31
	Max number of files supported.
#define	TSFS_BLOCKSIZE 512
	Size of block in bytes.
Enumerations
enum	tsfs_seek_origin { SEEK_SET, SEEK_CUR, SEEK_END }
	The relative starting point of seek operations. More...
Functions
status_t	tsfs_init (struct tsfs tsfs, struct block_device system_blockdevice, struct workqueue_task *system_ready_task)
	Initiates a Tiny Simple File System.
status_t	tsfs_open (struct tsfs tsfs, const char filename, struct tsfs_file *filehandle)
	Opens a file by populating a file handle.
status_t	tsfs_seek (struct tsfs_file *file, int32_t offset, enum tsfs_seek_origin origin)
	Manualy move the file cursor.
status_t	tsfs_read (struct tsfs tsfs, struct tsfs_file file, void buffer, uint32_t length, struct workqueue_task task)
	Reads a chunk of data from a file to a buffer.
void	tsfs_get_filename (struct tsfs tsfs, uint_fast8_t file_index, uint8_t buffer)
	Reads the filename of an indexed file into a buffer.
static uint32_t	tsfs_get_file_size (struct tsfs_file *file)
	Get the file size in bytes for file file.
static uint32_t	tsfs_nr_files (struct tsfs *tsfs)
	Returns the number of files present in a file system.
static uint32_t	tsfs_volume_size (struct tsfs *tsfs)
	Returns the size of the entire volume.
static uint32_t	tsfs_is_ready (struct tsfs *tsfs)
	Check if file system is ready for use.

static void	tsfs_buf_list_done (struct block_device bdev, struct block_request breq, struct slist *buf_list)
	Block device list complete callback.
static void	tsfs_read_page_done (struct block_device bdev, struct block_request breq)
	Block device request complete callback.

Detailed Description

file system.

This module provides mechanisms for data stored in a TSFS file system. Note: All data is stored using big endigan encoding, and translated to CPU specific endianess after being read into the file system.

In order to improve execution times most functions in this module assume input parameters are clean. This means that there are no sanity on any parameters unless it is explisitly stated in this document.

Define Documentation

#define TSFS_BLOCKSIZE 512

Size of block in bytes.

Definition at line 79 of file tsfs.h.

Referenced by tsfs_init(), and tsfs_read().

#define TSFS_FILENAME_LEN 8

Max characters in a filename.

Definition at line 68 of file tsfs.h.

Referenced by tsfs_get_filename().

#define TSFS_ID 0x17c1

Unique ID to identify TSFS.

Definition at line 66 of file tsfs.h.

#define TSFS_MAX_FILES 31

Max number of files supported.

Definition at line 75 of file tsfs.h.

Referenced by tsfs_init().

Enumeration Type Documentation

enum tsfs_seek_origin

The relative starting point of seek operations.

Enumerator:

SEEK_SET	Seek relative to beginning of file.
SEEK_CUR	Seek relative to current cursor position.
SEEK_END	Seek relative to end of file.

Definition at line 193 of file tsfs.h.

Function Documentation

static void tsfs_buf_list_done	(	struct block_device *	bdev,
		struct block_request *	breq,
		struct slist *	buf_list
	)			`[static]`

Block device list complete callback.

Definition at line 67 of file tsfs.c.

static uint32_t tsfs_get_file_size ( struct tsfs_file * file ) [inline, static]

Get the file size in bytes for file file.

Returns:: Size given in bytes for file file

Definition at line 223 of file tsfs.h.

References tsfs_file::end, and tsfs_file::start.

void tsfs_get_filename	(	struct tsfs *	tsfs,
		uint_fast8_t	file_index,
		uint8_t *	buffer
	)

Reads the filename of an indexed file into a buffer.

Note:: buffer must be able to hold at least TSFS_FILENAME_LEN bytes.

Parameters:

	tsfs	TSFS structure which holds file system information
	file_index	Index of file which name is to be fetched
	buffer	Buffer where filename will be written

Definition at line 475 of file tsfs.c.

References tsfs_filetable_entry::filename, memcpy(), and TSFS_FILENAME_LEN.

status_t tsfs_init	(	struct tsfs *	tsfs,
		struct block_device *	bdev,
		struct workqueue_task *	init_done_task
	)

Initiates a Tiny Simple File System.

The block device specified by system_blockdevice has to have a block size of TSFS_BLOCKSIZE bytes.

Immediately after returning from this function, the file system will have status ERR_BUSY. The system is ready for use when the status changes to STATUS_OK. This can be polled for, or the parameter init_done_task can be used to specify a task to be scheduled when the system is ready.

In case the data loaded from the block device is not TSFS compatible the file system will not schedule the callback task, and set its own status to ERR_BAD_FORMAT. At this point the file system has to be re-initialized with a valid block device if it is to be used.

Parameters:

	tsfs	TSFS structure which holds file system information
	bdev	Block device to read data from
	init_done_task	Callback task for when system is ready for use

Definition at line 232 of file tsfs.c.

References assert, tsfs::bdev, board_extram_pool, tsfs::buffer_data, CPU_DMA_ALIGN, tsfs::current_read_request, ERR_BUSY, ERR_NO_MEMORY, malloc(), physmem_alloc(), PHYSMEM_ALLOC_ERR, tsfs::status, STATUS_OK, tsfs_read_request::task, TSFS_BLOCKSIZE, and TSFS_MAX_FILES.

static uint32_t tsfs_is_ready ( struct tsfs * tsfs ) [inline, static]

Check if file system is ready for use.

Returns:: Returns true if a file system tsfs is ready for use

Definition at line 253 of file tsfs.h.

References tsfs::bdev, tsfs::status, and STATUS_OK.

static uint32_t tsfs_nr_files ( struct tsfs * tsfs ) [inline, static]

Returns the number of files present in a file system.

Returns:: The number of files in the file system tsfs

Definition at line 233 of file tsfs.h.

References tsfs::header, and tsfs_header::nr_files.

status_t tsfs_open	(	struct tsfs *	tsfs,
		const char *	filename,
		struct tsfs_file *	filehandle
	)

Opens a file by populating a file handle.

Searches through the filetable of tsfs and opens the first file that matches the filename string. Note that this can be a pointer to any normal character array, even though TSFS filenames do not have a termchar

Parameters:

	tsfs	TSFS structure which holds file system information
	filename	Name of file to be opened
	filehandle	File structure to store results

Return values:

	\ref	STATUS_OK if successful.
	\ref	ERR_INVALID_ARG if file is not found.

Definition at line 404 of file tsfs.c.

References tsfs_file::cursor, tsfs_file::end, ERR_INVALID_ARG, tsfs_filetable_entry::file_offset, tsfs_filetable_entry::file_size, tsfs::header, tsfs_header::nr_files, tsfs_file::start, and STATUS_OK.

status_t tsfs_read	(	struct tsfs *	tsfs,
		struct tsfs_file *	file,
		void *	buffer,
		uint32_t	length,
		struct workqueue_task *	task
	)

Reads a chunk of data from a file to a buffer.

Any file system can only issue one read request at a time, and hence if the system is busy reading another file tsfs_read will return ERR_BUSY. The user application should pick up on this and reschedule its read attempt.

The task is scheduled to execute once the copy operation is complete, but only if tsfs_read returns STATUS_OK. If it returns any error message, the task is not scheduled.

The length parameter is trimmed to never exceed the length of the file.

Parameters:

	tsfs	TSFS structure which holds file system information
	file	Handle of the file to be read from
	buffer	Pointer to buffer where data is read to
	length	Number of bytes to read
	task	Task to be scheduled upon successful completion

Return values:

	\ref	STATUS_OK if successful
	\ref	ERR_INVALID_ARG if trying to read at the end of a file, or trying to read 0 bytes.
	\ref	ERR_BUSY if file system is busy reading from another file.

Definition at line 317 of file tsfs.c.

References tsfs_read_request::buffer, tsfs::current_read_request, tsfs_read_request::cursor, tsfs_file::cursor, tsfs_file::end, ERR_BUSY, ERR_INVALID_ARG, ilog2(), tsfs::lba_in_buf, tsfs_read_request::remaining_bytes, tsfs::status, STATUS_OK, tsfs_read_request::task, and TSFS_BLOCKSIZE.

static void tsfs_read_page_done	(	struct block_device *	bdev,
		struct block_request *	breq
	)			`[static]`

Block device request complete callback.

Definition at line 76 of file tsfs.c.

References block_free_request(), block_request::context, tsfs::current_breq, and tsfs::page_read_callback.

status_t tsfs_seek	(	struct tsfs_file *	file,
		int32_t	offset,
		enum tsfs_seek_origin	origin
	)

Manualy move the file cursor.

Available offsets are found in tsfs_seek_origin. Note that to offset inwards from the end of the file, negative values should be used for offset. It is possible to seek the file cursor to any value, even invalid ones, so care should be taken when using this function. If an invalid value is passed for origin, the application will execute unhandled_case()

Parameters: