zephyr/subsys/fs/fcb/fcb_elem_info.c

150 lines
3.2 KiB
C

/*
* Copyright (c) 2017-2023 Nordic Semiconductor ASA
* Copyright (c) 2015 Runtime Inc
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr/sys/crc.h>
#include <zephyr/fs/fcb.h>
#include "fcb_priv.h"
#define FCB_FIXED_ENDMARKER 0xab
/*
* Given offset in flash sector, fill in rest of the fcb_entry, and crc8 over
* the data.
*/
static int
fcb_elem_crc8(struct fcb *_fcb, struct fcb_entry *loc, uint8_t *c8p)
{
uint8_t tmp_str[FCB_TMP_BUF_SZ];
int cnt;
int blk_sz;
uint8_t crc8;
uint16_t len;
uint32_t off;
uint32_t end;
int rc;
if (loc->fe_elem_off + 2 > loc->fe_sector->fs_size) {
return -ENOTSUP;
}
rc = fcb_flash_read(_fcb, loc->fe_sector, loc->fe_elem_off, tmp_str, 2);
if (rc) {
return -EIO;
}
cnt = fcb_get_len(_fcb, tmp_str, &len);
if (cnt < 0) {
return cnt;
}
loc->fe_data_off = loc->fe_elem_off + fcb_len_in_flash(_fcb, cnt);
loc->fe_data_len = len;
crc8 = CRC8_CCITT_INITIAL_VALUE;
crc8 = crc8_ccitt(crc8, tmp_str, cnt);
off = loc->fe_data_off;
end = loc->fe_data_off + len;
for (; off < end; off += blk_sz) {
blk_sz = end - off;
if (blk_sz > sizeof(tmp_str)) {
blk_sz = sizeof(tmp_str);
}
rc = fcb_flash_read(_fcb, loc->fe_sector, off, tmp_str, blk_sz);
if (rc) {
return -EIO;
}
crc8 = crc8_ccitt(crc8, tmp_str, blk_sz);
}
*c8p = crc8;
return 0;
}
#if IS_ENABLED(CONFIG_FCB_ALLOW_FIXED_ENDMARKER)
/* Given the offset in flash sector, calculate the FCB entry data offset and size, and set
* the fixed endmarker.
*/
static int
fcb_elem_endmarker_fixed(struct fcb *_fcb, struct fcb_entry *loc, uint8_t *em)
{
uint8_t tmp_str[2];
int cnt;
uint16_t len;
int rc;
if (loc->fe_elem_off + 2 > loc->fe_sector->fs_size) {
return -ENOTSUP;
}
rc = fcb_flash_read(_fcb, loc->fe_sector, loc->fe_elem_off, tmp_str, 2);
if (rc) {
return -EIO;
}
cnt = fcb_get_len(_fcb, tmp_str, &len);
if (cnt < 0) {
return cnt;
}
loc->fe_data_off = loc->fe_elem_off + fcb_len_in_flash(_fcb, cnt);
loc->fe_data_len = len;
*em = FCB_FIXED_ENDMARKER;
return 0;
}
#endif /* IS_ENABLED(CONFIG_FCB_ALLOW_FIXED_ENDMARKER) */
/* Given the offset in flash sector, calculate the FCB entry data offset and size, and calculate
* the expected endmarker.
*/
int
fcb_elem_endmarker(struct fcb *_fcb, struct fcb_entry *loc, uint8_t *em)
{
#if IS_ENABLED(CONFIG_FCB_ALLOW_FIXED_ENDMARKER)
if (_fcb->f_flags & FCB_FLAGS_CRC_DISABLED) {
return fcb_elem_endmarker_fixed(_fcb, loc, em);
}
#endif /* IS_ENABLED(CONFIG_FCB_ALLOW_FIXED_ENDMARKER) */
return fcb_elem_crc8(_fcb, loc, em);
}
/* Given the offset in flash sector, calculate the FCB entry data offset and size, and verify that
* the FCB entry endmarker is correct.
*/
int fcb_elem_info(struct fcb *_fcb, struct fcb_entry *loc)
{
int rc;
uint8_t em;
uint8_t fl_em;
off_t off;
rc = fcb_elem_endmarker(_fcb, loc, &em);
if (rc) {
return rc;
}
off = loc->fe_data_off + fcb_len_in_flash(_fcb, loc->fe_data_len);
rc = fcb_flash_read(_fcb, loc->fe_sector, off, &fl_em, sizeof(fl_em));
if (rc) {
return -EIO;
}
if (IS_ENABLED(CONFIG_FCB_ALLOW_FIXED_ENDMARKER) && (fl_em != em)) {
rc = fcb_elem_crc8(_fcb, loc, &em);
if (rc) {
return rc;
}
}
if (fl_em != em) {
return -EBADMSG;
}
return 0;
}