104 lines
3.1 KiB
C
104 lines
3.1 KiB
C
#include <drivers/flash.h>
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#include <storage/flash_map.h>
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#include <string.h>
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#include <sys/crc.h>
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#include "ens_error.h"
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#include "ens_fs.h"
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#define SEED 42
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int ens_fs_init(ens_fs_t* fs, uint8_t id, uint64_t entry_size) {
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if (flash_area_open(id, &fs->area)) {
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// opening of flash area was not successful
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return -ENS_INTERR;
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}
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// check, if entry size is multiple of flash_area_align
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if ((entry_size % flash_area_align(fs->area)) != 0) {
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flash_area_close(fs->area);
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return -ENS_INVARG;
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}
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fs->entry_size = entry_size;
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// get all information needed for the needed for the fs
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const struct device* dev = flash_area_get_device(fs->area);
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fs->sector_count = flash_get_page_count(dev);
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struct flash_pages_info info;
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if (flash_get_page_info_by_offs(dev, fs->area->fa_off, &info)) {
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// on error, close the flash area
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flash_area_close(fs->area);
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return -ENS_INTERR;
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}
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fs->sector_size = info.size;
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return 0;
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}
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int ens_fs_read(ens_fs_t* fs, uint64_t id, void* dist) {
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// read the entry from flash
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uint64_t offset = id * fs->entry_size;
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if (flash_area_read(fs->area, offset, dist, fs->entry_size)) {
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// opening of flash area was not successful
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return -ENS_INTERR;
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}
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// check, if checksum and not-deleted flag are as expected
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uint8_t* obj = dist;
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uint8_t metadata = crc7_be(SEED, obj, fs->entry_size - 1) | 1;
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int isInvalid = memcmp(&obj[fs->entry_size - 1], &metadata, 1);
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if (isInvalid) {
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// if checksum is not equal to calculated checksum or if deleted flag is not 1, set memory to 0
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memset(dist, 0, fs->entry_size);
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// we do not know, if object got deleted or data is corrupt
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return -ENS_NOENT;
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}
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return 0;
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}
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int ens_fs_write(ens_fs_t* fs, uint64_t id, void* data) {
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// set CRC and not-deleted-flag
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uint8_t* obj = data;
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obj[fs->entry_size - 1] = crc7_be(SEED, obj, fs->entry_size - 1) | 1;
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uint64_t offset = id * fs->entry_size;
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if (flash_area_write(fs->area, offset, data, fs->entry_size)) {
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// writing to flash was not successful
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return -ENS_INTERR;
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}
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return 0;
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}
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int ens_fs_delete(ens_fs_t* fs, uint64_t id) {
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uint8_t data[fs->entry_size];
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uint64_t offset = id * fs->entry_size;
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if (flash_area_read(fs->area, offset, data, fs->entry_size)) {
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// reading was not successful
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return -ENS_INTERR;
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}
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// set memory to 0, so not-deleted flag is 0
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memset(data, 0, fs->entry_size);
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if (flash_area_write(fs->area, offset, data, fs->entry_size)) {
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// writing was not successful
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return -ENS_INTERR;
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}
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return 0;
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}
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int ens_fs_page_erase(ens_fs_t* fs, uint64_t offset, uint64_t sector_count) {
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// calculate the next page start before (or at) the given offset
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uint64_t start = (offset - offset % fs->sector_size) * fs->entry_size;
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// erase given amount of pages, starting for the given offset
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if (flash_area_erase(fs->area, start, fs->sector_size * sector_count)) {
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return -ENS_INTERR;
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}
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return 0;
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}
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