fcb API

Flash Circular Buffer APIs. More...

Typedefs
typedef int(*	fcb_walk_cb) (struct fcb_entry_ctx *loc_ctx, void *arg)
	FCB Walk callback function type.

Functions
int	fcb_init (int f_area_id, struct fcb *fcb)
	Initialize FCB instance.
int	fcb_append (struct fcb *fcb, uint16_t len, struct fcb_entry *loc)
	Appends an entry to circular buffer.
int	fcb_append_finish (struct fcb *fcb, struct fcb_entry *append_loc)
	Finishes entry append operation.
int	fcb_walk (struct fcb *fcb, struct flash_sector *sector, fcb_walk_cb cb, void *cb_arg)
	Walk over all entries in the FCB sector.
int	fcb_getnext (struct fcb *fcb, struct fcb_entry *loc)
	Get next fcb entry location.
int	fcb_rotate (struct fcb *fcb)
	Rotate fcb sectors.
int	fcb_append_to_scratch (struct fcb *fcb)
	Start using the scratch block.
int	fcb_free_sector_cnt (struct fcb *fcb)
	Get free sector count.
int	fcb_is_empty (struct fcb *fcb)
	Check whether FCB has any data.
int	fcb_offset_last_n (struct fcb *fcb, uint8_t entries, struct fcb_entry *last_n_entry)
	Finds the fcb entry that gives back up to n entries at the end.
int	fcb_clear (struct fcb *fcb)
	Clear fcb instance storage.

Detailed Description

Flash Circular Buffer APIs.

Typedef Documentation

fcb_walk_cb

typedef int(* fcb_walk_cb) (struct fcb_entry_ctx *loc_ctx, void *arg)

#include <zephyr/fs/fcb.h>

FCB Walk callback function type.

Type of function which is expected to be called while walking over fcb entries thanks to a fcb_walk call.

Entry data can be read using flash_area_read(), using loc_ctx fields as arguments. If cb wants to stop the walk, it should return non-zero value.

Parameters

[in]	loc_ctx	entry location information (full context)
[in,out]	arg	callback context, transferred from fcb_walk.

Returns

0 continue walking, non-zero stop walking.

Function Documentation

fcb_append()

int fcb_append	(	struct fcb *	fcb,
		uint16_t	len,
		struct fcb_entry *	loc
	)

#include <zephyr/fs/fcb.h>

Appends an entry to circular buffer.

When writing the contents for the entry, use loc->fe_sector and loc->fe_data_off with flash_area_write() to fcb flash_area. When you're finished, call fcb_append_finish() with loc as argument.

Parameters

[in]	fcb	FCB instance structure.
[in]	len	Length of data which are expected to be written as the entry payload.
[out]	loc	entry location information

Returns

0 on success, non-zero on failure.

fcb_append_finish()

int fcb_append_finish	(	struct fcb *	fcb,
		struct fcb_entry *	append_loc
	)

#include <zephyr/fs/fcb.h>

Finishes entry append operation.

Parameters

[in]	fcb	FCB instance structure.
[in]	append_loc	entry location information

Returns

0 on success, non-zero on failure.

fcb_append_to_scratch()

int fcb_append_to_scratch

(

struct fcb *

fcb

)

#include <zephyr/fs/fcb.h>

Start using the scratch block.

Take one of the scratch blocks into use. So a scratch sector becomes active sector to which entries can be appended.

Parameters

[in]

fcb

FCB instance structure.

Returns

0 on success, non-zero on failure.

fcb_clear()

int fcb_clear

(

struct fcb *

fcb

)

#include <zephyr/fs/fcb.h>

Clear fcb instance storage.

Parameters

[in]

fcb

FCB instance structure.

Returns

0 on success; non-zero on failure

fcb_free_sector_cnt()

int fcb_free_sector_cnt

(

struct fcb *

fcb

)

#include <zephyr/fs/fcb.h>

Get free sector count.

Parameters

[in]

fcb

FCB instance structure.

Returns

Number of free sectors.

fcb_getnext()

int fcb_getnext	(	struct fcb *	fcb,
		struct fcb_entry *	loc
	)

#include <zephyr/fs/fcb.h>

Get next fcb entry location.

Function to obtain fcb entry location in relation to entry pointed by

loc. If loc->fe_sector is set and loc->fe_elem_off is not 0 function fetches next fcb entry location. If loc->fe_sector is NULL function fetches the oldest entry location within FCB storage. loc->fe_sector is set and loc->fe_elem_off is 0 function fetches the first entry location in the fcb sector.

Parameters

[in]	fcb	FCB instance structure.
[in,out]	loc	entry location information

Returns

0 on success, non-zero on failure.

fcb_init()

int fcb_init	(	int	f_area_id,
		struct fcb *	fcb
	)

#include <zephyr/fs/fcb.h>

Initialize FCB instance.

Parameters

[in]	f_area_id	ID of flash area where fcb storage resides.
[in,out]	fcb	FCB instance structure.

Returns

0 on success, non-zero on failure.

fcb_is_empty()

int fcb_is_empty

(

struct fcb *

fcb

)

#include <zephyr/fs/fcb.h>

Check whether FCB has any data.

Parameters

[in]

fcb

FCB instance structure.

Returns

Positive value if fcb is empty, otherwise 0.

fcb_offset_last_n()

int fcb_offset_last_n	(	struct fcb *	fcb,
		uint8_t	entries,
		struct fcb_entry *	last_n_entry
	)

#include <zephyr/fs/fcb.h>

Finds the fcb entry that gives back up to n entries at the end.

Parameters

[in]	fcb	FCB instance structure.
[in]	entries	number of fcb entries the user wants to get
[out]	last_n_entry	last_n_entry the fcb_entry to be returned

Returns

0 on there are any fcbs available; -ENOENT otherwise

fcb_rotate()

int fcb_rotate

(

struct fcb *

fcb

)

#include <zephyr/fs/fcb.h>

Rotate fcb sectors.

Function erases the data from oldest sector. Upon that the next sector becomes the oldest. Active sector is also switched if needed.

Parameters

[in]

fcb

FCB instance structure.

fcb_walk()

int fcb_walk	(	struct fcb *	fcb,
		struct flash_sector *	sector,
		fcb_walk_cb	cb,
		void *	cb_arg
	)

#include <zephyr/fs/fcb.h>

Walk over all entries in the FCB sector.

Parameters

[in]	sector	fcb sector to be walked. If null, traverse entire storage.
[in]	fcb	FCB instance structure.
[in]	cb	pointer to the function which gets called for every entry. If cb wants to stop the walk, it should return non-zero value.
[in,out]	cb_arg	callback context, transferred to the callback implementation.

Returns

0 on success, negative on failure (or transferred form callback return-value), positive transferred form callback return-value