fcb.h

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/*
 * Copyright (c) 2017-2020 Nordic Semiconductor ASA
 * Copyright (c) 2015 Runtime Inc
 *
 * SPDX-License-Identifier: Apache-2.0
 */
#ifndef ZEPHYR_INCLUDE_FS_FCB_H_
#define ZEPHYR_INCLUDE_FS_FCB_H_
 
/*
 * Flash circular buffer.
 */
#include <inttypes.h>
#include <limits.h>
 
#include <storage/flash_map.h>
 
#include <kernel.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
#define FCB_MAX_LEN     (CHAR_MAX | CHAR_MAX << 7) 
struct fcb_entry {
        struct flash_sector *fe_sector;
        uint32_t fe_elem_off;
        uint32_t fe_data_off;
        uint16_t fe_data_len; 
};
 
#define FCB_ENTRY_FA_DATA_OFF(entry) (entry.fe_sector->fs_off +\
                                      entry.fe_data_off)
struct fcb_entry_ctx {
        struct fcb_entry loc; 
        const struct flash_area *fap;
};
 
struct fcb {
        /* Caller of fcb_init fills this in */
        uint32_t f_magic;
        uint8_t f_version; 
        uint8_t f_sector_cnt; 
        uint8_t f_scratch_cnt;
        struct flash_sector *f_sectors;
        /* Flash circular buffer internal state */
        struct k_mutex f_mtx;
        struct flash_sector *f_oldest;
        struct fcb_entry f_active; 
        uint16_t f_active_id;
        uint8_t f_align;
        const struct flash_area *fap;
        uint8_t f_erase_value;
};
 
int fcb_init(int f_area_id, struct fcb *fcb);
 
int fcb_append(struct fcb *fcb, uint16_t len, struct fcb_entry *loc);
 
int fcb_append_finish(struct fcb *fcb, struct fcb_entry *append_loc);
 
typedef int (*fcb_walk_cb)(struct fcb_entry_ctx *loc_ctx, void *arg);
 
int fcb_walk(struct fcb *fcb, struct flash_sector *sector, fcb_walk_cb cb,
             void *cb_arg);
 
int fcb_getnext(struct fcb *fcb, struct fcb_entry *loc);
 
/*
 * 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.
 *
 * @param[in] fcb FCB instance structure.
 */
int fcb_rotate(struct fcb *fcb);
 
/*
 * 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.
 *
 * @param[in] fcb FCB instance structure.
 *
 * @return 0 on success, non-zero on failure.
 */
int fcb_append_to_scratch(struct fcb *fcb);
 
int fcb_free_sector_cnt(struct fcb *fcb);
 
int fcb_is_empty(struct fcb *fcb);
 
int fcb_offset_last_n(struct fcb *fcb, uint8_t entries,
                      struct fcb_entry *last_n_entry);
 
int fcb_clear(struct fcb *fcb);
 
int fcb_flash_read(const struct fcb *fcb, const struct flash_sector *sector,
                   off_t off, void *dst, size_t len);
 
int fcb_flash_write(const struct fcb *fcb, const struct flash_sector *sector,
                    off_t off, const void *src, size_t len);
 
#ifdef __cplusplus
}
#endif
 
#endif /* ZEPHYR_INCLUDE_FS_FCB_H_ */