kamkow1/my-os-project2
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Implement storedevs, prepare to port littlefs

Browse Source
This commit is contained in:
Kamil Kowalczyk
2025-08-16 12:34:36 +02:00
parent c936910199
commit 2b0566c56f
91 changed files with 54963 additions and 37 deletions
Download Patch File Download Diff File Expand all files Collapse all files

739
kernel/fs/littlefs/bd/lfs_emubd.c Normal file
View File

@ -0,0 +1,739 @@
/*
* Emulating block device, wraps filebd and rambd while providing a bunch
* of hooks for testing littlefs in various conditions.
*
* Copyright (c) 2022, The littlefs authors.
* Copyright (c) 2017, Arm Limited. All rights reserved.
* SPDX-License-Identifier: BSD-3-Clause
*/
#ifndef _POSIX_C_SOURCE
#define _POSIX_C_SOURCE 199309L
#endif
#include "bd/lfs_emubd.h"
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>
#ifdef _WIN32
#include <windows.h>
#endif
// access to lazily-allocated/copy-on-write blocks
//
// Note we can only modify a block if we have exclusive access to it (rc == 1)
//
static lfs_emubd_block_t *lfs_emubd_incblock(lfs_emubd_block_t *block) {
if (block) {
block->rc += 1;
}
return block;
}
static void lfs_emubd_decblock(lfs_emubd_block_t *block) {
if (block) {
block->rc -= 1;
if (block->rc == 0) {
free(block);
}
}
}
static lfs_emubd_block_t *lfs_emubd_mutblock(
const struct lfs_config *cfg,
lfs_emubd_block_t **block) {
lfs_emubd_t *bd = cfg->context;
lfs_emubd_block_t *block_ = *block;
if (block_ && block_->rc == 1) {
// rc == 1? can modify
return block_;
} else if (block_) {
// rc > 1? need to create a copy
lfs_emubd_block_t *nblock = malloc(
sizeof(lfs_emubd_block_t) + bd->cfg->erase_size);
if (!nblock) {
return NULL;
}
memcpy(nblock, block_,
sizeof(lfs_emubd_block_t) + bd->cfg->erase_size);
nblock->rc = 1;
lfs_emubd_decblock(block_);
*block = nblock;
return nblock;
} else {
// no block? need to allocate
lfs_emubd_block_t *nblock = malloc(
sizeof(lfs_emubd_block_t) + bd->cfg->erase_size);
if (!nblock) {
return NULL;
}
nblock->rc = 1;
nblock->wear = 0;
// zero for consistency
memset(nblock->data,
(bd->cfg->erase_value != -1) ? bd->cfg->erase_value : 0,
bd->cfg->erase_size);
*block = nblock;
return nblock;
}
}
// emubd create/destroy
int lfs_emubd_create(const struct lfs_config *cfg,
const struct lfs_emubd_config *bdcfg) {
LFS_EMUBD_TRACE("lfs_emubd_create(%p {.context=%p, "
".read=%p, .prog=%p, .erase=%p, .sync=%p}, "
"%p {.read_size=%"PRIu32", .prog_size=%"PRIu32", "
".erase_size=%"PRIu32", .erase_count=%"PRIu32", "
".erase_value=%"PRId32", .erase_cycles=%"PRIu32", "
".badblock_behavior=%"PRIu8", .power_cycles=%"PRIu32", "
".powerloss_behavior=%"PRIu8", .powerloss_cb=%p, "
".powerloss_data=%p, .track_branches=%d})",
(void*)cfg, cfg->context,
(void*)(uintptr_t)cfg->read, (void*)(uintptr_t)cfg->prog,
(void*)(uintptr_t)cfg->erase, (void*)(uintptr_t)cfg->sync,
(void*)bdcfg,
bdcfg->read_size, bdcfg->prog_size, bdcfg->erase_size,
bdcfg->erase_count, bdcfg->erase_value, bdcfg->erase_cycles,
bdcfg->badblock_behavior, bdcfg->power_cycles,
bdcfg->powerloss_behavior, (void*)(uintptr_t)bdcfg->powerloss_cb,
bdcfg->powerloss_data, bdcfg->track_branches);
lfs_emubd_t *bd = cfg->context;
bd->cfg = bdcfg;
// allocate our block array, all blocks start as uninitialized
bd->blocks = malloc(bd->cfg->erase_count * sizeof(lfs_emubd_block_t*));
if (!bd->blocks) {
LFS_EMUBD_TRACE("lfs_emubd_create -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
memset(bd->blocks, 0, bd->cfg->erase_count * sizeof(lfs_emubd_block_t*));
// setup testing things
bd->readed = 0;
bd->proged = 0;
bd->erased = 0;
bd->power_cycles = bd->cfg->power_cycles;
bd->ooo_block = -1;
bd->ooo_data = NULL;
bd->disk = NULL;
if (bd->cfg->disk_path) {
bd->disk = malloc(sizeof(lfs_emubd_disk_t));
if (!bd->disk) {
LFS_EMUBD_TRACE("lfs_emubd_create -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
bd->disk->rc = 1;
bd->disk->scratch = NULL;
#ifdef _WIN32
bd->disk->fd = open(bd->cfg->disk_path,
O_RDWR | O_CREAT | O_BINARY, 0666);
#else
bd->disk->fd = open(bd->cfg->disk_path,
O_RDWR | O_CREAT, 0666);
#endif
if (bd->disk->fd < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_create -> %d", err);
return err;
}
// if we're emulating erase values, we can keep a block around in
// memory of just the erase state to speed up emulated erases
if (bd->cfg->erase_value != -1) {
bd->disk->scratch = malloc(bd->cfg->erase_size);
if (!bd->disk->scratch) {
LFS_EMUBD_TRACE("lfs_emubd_create -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
memset(bd->disk->scratch,
bd->cfg->erase_value,
bd->cfg->erase_size);
// go ahead and erase all of the disk, otherwise the file will not
// match our internal representation
for (size_t i = 0; i < bd->cfg->erase_count; i++) {
ssize_t res = write(bd->disk->fd,
bd->disk->scratch,
bd->cfg->erase_size);
if (res < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_create -> %d", err);
return err;
}
}
}
}
LFS_EMUBD_TRACE("lfs_emubd_create -> %d", 0);
return 0;
}
int lfs_emubd_destroy(const struct lfs_config *cfg) {
LFS_EMUBD_TRACE("lfs_emubd_destroy(%p)", (void*)cfg);
lfs_emubd_t *bd = cfg->context;
// decrement reference counts
for (lfs_block_t i = 0; i < bd->cfg->erase_count; i++) {
lfs_emubd_decblock(bd->blocks[i]);
}
free(bd->blocks);
// clean up other resources
lfs_emubd_decblock(bd->ooo_data);
if (bd->disk) {
bd->disk->rc -= 1;
if (bd->disk->rc == 0) {
close(bd->disk->fd);
free(bd->disk->scratch);
free(bd->disk);
}
}
LFS_EMUBD_TRACE("lfs_emubd_destroy -> %d", 0);
return 0;
}
// powerloss hook
static int lfs_emubd_powerloss(const struct lfs_config *cfg) {
lfs_emubd_t *bd = cfg->context;
// emulate out-of-order writes?
lfs_emubd_block_t *ooo_data = NULL;
if (bd->cfg->powerloss_behavior == LFS_EMUBD_POWERLOSS_OOO
&& bd->ooo_block != -1) {
// since writes between syncs are allowed to be out-of-order, it
// shouldn't hurt to restore the first write on powerloss, right?
ooo_data = bd->blocks[bd->ooo_block];
bd->blocks[bd->ooo_block] = lfs_emubd_incblock(bd->ooo_data);
// mirror to disk file?
if (bd->disk
&& (bd->blocks[bd->ooo_block]
|| bd->cfg->erase_value != -1)) {
off_t res1 = lseek(bd->disk->fd,
(off_t)bd->ooo_block*bd->cfg->erase_size,
SEEK_SET);
if (res1 < 0) {
return -errno;
}
ssize_t res2 = write(bd->disk->fd,
(bd->blocks[bd->ooo_block])
? bd->blocks[bd->ooo_block]->data
: bd->disk->scratch,
bd->cfg->erase_size);
if (res2 < 0) {
return -errno;
}
}
}
// simulate power loss
bd->cfg->powerloss_cb(bd->cfg->powerloss_data);
// if we continue, undo out-of-order write emulation
if (bd->cfg->powerloss_behavior == LFS_EMUBD_POWERLOSS_OOO
&& bd->ooo_block != -1) {
lfs_emubd_decblock(bd->blocks[bd->ooo_block]);
bd->blocks[bd->ooo_block] = ooo_data;
// mirror to disk file?
if (bd->disk
&& (bd->blocks[bd->ooo_block]
|| bd->cfg->erase_value != -1)) {
off_t res1 = lseek(bd->disk->fd,
(off_t)bd->ooo_block*bd->cfg->erase_size,
SEEK_SET);
if (res1 < 0) {
return -errno;
}
ssize_t res2 = write(bd->disk->fd,
(bd->blocks[bd->ooo_block])
? bd->blocks[bd->ooo_block]->data
: bd->disk->scratch,
bd->cfg->erase_size);
if (res2 < 0) {
return -errno;
}
}
}
return 0;
}
// block device API
int lfs_emubd_read(const struct lfs_config *cfg, lfs_block_t block,
lfs_off_t off, void *buffer, lfs_size_t size) {
LFS_EMUBD_TRACE("lfs_emubd_read(%p, "
"0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
(void*)cfg, block, off, buffer, size);
lfs_emubd_t *bd = cfg->context;
// check if read is valid
LFS_ASSERT(block < bd->cfg->erase_count);
LFS_ASSERT(off % bd->cfg->read_size == 0);
LFS_ASSERT(size % bd->cfg->read_size == 0);
LFS_ASSERT(off+size <= bd->cfg->erase_size);
// get the block
const lfs_emubd_block_t *b = bd->blocks[block];
if (b) {
// block bad?
if (bd->cfg->erase_cycles && b->wear >= bd->cfg->erase_cycles &&
bd->cfg->badblock_behavior == LFS_EMUBD_BADBLOCK_READERROR) {
LFS_EMUBD_TRACE("lfs_emubd_read -> %d", LFS_ERR_CORRUPT);
return LFS_ERR_CORRUPT;
}
// read data
memcpy(buffer, &b->data[off], size);
} else {
// zero for consistency
memset(buffer,
(bd->cfg->erase_value != -1) ? bd->cfg->erase_value : 0,
size);
}
// track reads
bd->readed += size;
if (bd->cfg->read_sleep) {
int err = nanosleep(&(struct timespec){
.tv_sec=bd->cfg->read_sleep/1000000000,
.tv_nsec=bd->cfg->read_sleep%1000000000},
NULL);
if (err) {
err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_read -> %d", err);
return err;
}
}
LFS_EMUBD_TRACE("lfs_emubd_read -> %d", 0);
return 0;
}
int lfs_emubd_prog(const struct lfs_config *cfg, lfs_block_t block,
lfs_off_t off, const void *buffer, lfs_size_t size) {
LFS_EMUBD_TRACE("lfs_emubd_prog(%p, "
"0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
(void*)cfg, block, off, buffer, size);
lfs_emubd_t *bd = cfg->context;
// check if write is valid
LFS_ASSERT(block < bd->cfg->erase_count);
LFS_ASSERT(off % bd->cfg->prog_size == 0);
LFS_ASSERT(size % bd->cfg->prog_size == 0);
LFS_ASSERT(off+size <= bd->cfg->erase_size);
// get the block
lfs_emubd_block_t *b = lfs_emubd_mutblock(cfg, &bd->blocks[block]);
if (!b) {
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
// block bad?
if (bd->cfg->erase_cycles && b->wear >= bd->cfg->erase_cycles) {
if (bd->cfg->badblock_behavior ==
LFS_EMUBD_BADBLOCK_PROGERROR) {
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", LFS_ERR_CORRUPT);
return LFS_ERR_CORRUPT;
} else if (bd->cfg->badblock_behavior ==
LFS_EMUBD_BADBLOCK_PROGNOOP ||
bd->cfg->badblock_behavior ==
LFS_EMUBD_BADBLOCK_ERASENOOP) {
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", 0);
return 0;
}
}
// were we erased properly?
if (bd->cfg->erase_value != -1) {
for (lfs_off_t i = 0; i < size; i++) {
LFS_ASSERT(b->data[off+i] == bd->cfg->erase_value);
}
}
// prog data
memcpy(&b->data[off], buffer, size);
// mirror to disk file?
if (bd->disk) {
off_t res1 = lseek(bd->disk->fd,
(off_t)block*bd->cfg->erase_size + (off_t)off,
SEEK_SET);
if (res1 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", err);
return err;
}
ssize_t res2 = write(bd->disk->fd, buffer, size);
if (res2 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", err);
return err;
}
}
// track progs
bd->proged += size;
if (bd->cfg->prog_sleep) {
int err = nanosleep(&(struct timespec){
.tv_sec=bd->cfg->prog_sleep/1000000000,
.tv_nsec=bd->cfg->prog_sleep%1000000000},
NULL);
if (err) {
err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", err);
return err;
}
}
// lose power?
if (bd->power_cycles > 0) {
bd->power_cycles -= 1;
if (bd->power_cycles == 0) {
int err = lfs_emubd_powerloss(cfg);
if (err) {
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", err);
return err;
}
}
}
LFS_EMUBD_TRACE("lfs_emubd_prog -> %d", 0);
return 0;
}
int lfs_emubd_erase(const struct lfs_config *cfg, lfs_block_t block) {
LFS_EMUBD_TRACE("lfs_emubd_erase(%p, 0x%"PRIx32" (%"PRIu32"))",
(void*)cfg, block, ((lfs_emubd_t*)cfg->context)->cfg->erase_size);
lfs_emubd_t *bd = cfg->context;
// check if erase is valid
LFS_ASSERT(block < bd->cfg->erase_count);
// emulate out-of-order writes? save first write
if (bd->cfg->powerloss_behavior == LFS_EMUBD_POWERLOSS_OOO
&& bd->ooo_block == -1) {
bd->ooo_block = block;
bd->ooo_data = lfs_emubd_incblock(bd->blocks[block]);
}
// get the block
lfs_emubd_block_t *b = lfs_emubd_mutblock(cfg, &bd->blocks[block]);
if (!b) {
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
// block bad?
if (bd->cfg->erase_cycles) {
if (b->wear >= bd->cfg->erase_cycles) {
if (bd->cfg->badblock_behavior ==
LFS_EMUBD_BADBLOCK_ERASEERROR) {
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", LFS_ERR_CORRUPT);
return LFS_ERR_CORRUPT;
} else if (bd->cfg->badblock_behavior ==
LFS_EMUBD_BADBLOCK_ERASENOOP) {
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", 0);
return 0;
}
} else {
// mark wear
b->wear += 1;
}
}
// emulate an erase value?
if (bd->cfg->erase_value != -1) {
memset(b->data, bd->cfg->erase_value, bd->cfg->erase_size);
// mirror to disk file?
if (bd->disk) {
off_t res1 = lseek(bd->disk->fd,
(off_t)block*bd->cfg->erase_size,
SEEK_SET);
if (res1 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", err);
return err;
}
ssize_t res2 = write(bd->disk->fd,
bd->disk->scratch,
bd->cfg->erase_size);
if (res2 < 0) {
int err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", err);
return err;
}
}
}
// track erases
bd->erased += bd->cfg->erase_size;
if (bd->cfg->erase_sleep) {
int err = nanosleep(&(struct timespec){
.tv_sec=bd->cfg->erase_sleep/1000000000,
.tv_nsec=bd->cfg->erase_sleep%1000000000},
NULL);
if (err) {
err = -errno;
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", err);
return err;
}
}
// lose power?
if (bd->power_cycles > 0) {
bd->power_cycles -= 1;
if (bd->power_cycles == 0) {
int err = lfs_emubd_powerloss(cfg);
if (err) {
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", err);
return err;
}
}
}
LFS_EMUBD_TRACE("lfs_emubd_erase -> %d", 0);
return 0;
}
int lfs_emubd_sync(const struct lfs_config *cfg) {
LFS_EMUBD_TRACE("lfs_emubd_sync(%p)", (void*)cfg);
lfs_emubd_t *bd = cfg->context;
// emulate out-of-order writes? reset first write, writes
// cannot be out-of-order across sync
if (bd->cfg->powerloss_behavior == LFS_EMUBD_POWERLOSS_OOO) {
lfs_emubd_decblock(bd->ooo_data);
bd->ooo_block = -1;
bd->ooo_data = NULL;
}
LFS_EMUBD_TRACE("lfs_emubd_sync -> %d", 0);
return 0;
}
/// Additional extended API for driving test features ///
static int lfs_emubd_crc_(const struct lfs_config *cfg,
lfs_block_t block, uint32_t *crc) {
lfs_emubd_t *bd = cfg->context;
// check if crc is valid
LFS_ASSERT(block < cfg->block_count);
// crc the block
uint32_t crc_ = 0xffffffff;
const lfs_emubd_block_t *b = bd->blocks[block];
if (b) {
crc_ = lfs_crc(crc_, b->data, cfg->block_size);
} else {
uint8_t erase_value = (bd->cfg->erase_value != -1)
? bd->cfg->erase_value
: 0;
for (lfs_size_t i = 0; i < cfg->block_size; i++) {
crc_ = lfs_crc(crc_, &erase_value, 1);
}
}
*crc = 0xffffffff ^ crc_;
return 0;
}
int lfs_emubd_crc(const struct lfs_config *cfg,
lfs_block_t block, uint32_t *crc) {
LFS_EMUBD_TRACE("lfs_emubd_crc(%p, %"PRIu32", %p)",
(void*)cfg, block, crc);
int err = lfs_emubd_crc_(cfg, block, crc);
LFS_EMUBD_TRACE("lfs_emubd_crc -> %d", err);
return err;
}
int lfs_emubd_bdcrc(const struct lfs_config *cfg, uint32_t *crc) {
LFS_EMUBD_TRACE("lfs_emubd_bdcrc(%p, %p)", (void*)cfg, crc);
uint32_t crc_ = 0xffffffff;
for (lfs_block_t i = 0; i < cfg->block_count; i++) {
uint32_t i_crc;
int err = lfs_emubd_crc_(cfg, i, &i_crc);
if (err) {
LFS_EMUBD_TRACE("lfs_emubd_bdcrc -> %d", err);
return err;
}
crc_ = lfs_crc(crc_, &i_crc, sizeof(uint32_t));
}
*crc = 0xffffffff ^ crc_;
LFS_EMUBD_TRACE("lfs_emubd_bdcrc -> %d", 0);
return 0;
}
lfs_emubd_sio_t lfs_emubd_readed(const struct lfs_config *cfg) {
LFS_EMUBD_TRACE("lfs_emubd_readed(%p)", (void*)cfg);
lfs_emubd_t *bd = cfg->context;
LFS_EMUBD_TRACE("lfs_emubd_readed -> %"PRIu64, bd->readed);
return bd->readed;
}
lfs_emubd_sio_t lfs_emubd_proged(const struct lfs_config *cfg) {
LFS_EMUBD_TRACE("lfs_emubd_proged(%p)", (void*)cfg);
lfs_emubd_t *bd = cfg->context;
LFS_EMUBD_TRACE("lfs_emubd_proged -> %"PRIu64, bd->proged);
return bd->proged;
}
lfs_emubd_sio_t lfs_emubd_erased(const struct lfs_config *cfg) {
LFS_EMUBD_TRACE("lfs_emubd_erased(%p)", (void*)cfg);
lfs_emubd_t *bd = cfg->context;
LFS_EMUBD_TRACE("lfs_emubd_erased -> %"PRIu64, bd->erased);
return bd->erased;
}
int lfs_emubd_setreaded(const struct lfs_config *cfg, lfs_emubd_io_t readed) {
LFS_EMUBD_TRACE("lfs_emubd_setreaded(%p, %"PRIu64")", (void*)cfg, readed);
lfs_emubd_t *bd = cfg->context;
bd->readed = readed;
LFS_EMUBD_TRACE("lfs_emubd_setreaded -> %d", 0);
return 0;
}
int lfs_emubd_setproged(const struct lfs_config *cfg, lfs_emubd_io_t proged) {
LFS_EMUBD_TRACE("lfs_emubd_setproged(%p, %"PRIu64")", (void*)cfg, proged);
lfs_emubd_t *bd = cfg->context;
bd->proged = proged;
LFS_EMUBD_TRACE("lfs_emubd_setproged -> %d", 0);
return 0;
}
int lfs_emubd_seterased(const struct lfs_config *cfg, lfs_emubd_io_t erased) {
LFS_EMUBD_TRACE("lfs_emubd_seterased(%p, %"PRIu64")", (void*)cfg, erased);
lfs_emubd_t *bd = cfg->context;
bd->erased = erased;
LFS_EMUBD_TRACE("lfs_emubd_seterased -> %d", 0);
return 0;
}
lfs_emubd_swear_t lfs_emubd_wear(const struct lfs_config *cfg,
lfs_block_t block) {
LFS_EMUBD_TRACE("lfs_emubd_wear(%p, %"PRIu32")", (void*)cfg, block);
lfs_emubd_t *bd = cfg->context;
// check if block is valid
LFS_ASSERT(block < bd->cfg->erase_count);
// get the wear
lfs_emubd_wear_t wear;
const lfs_emubd_block_t *b = bd->blocks[block];
if (b) {
wear = b->wear;
} else {
wear = 0;
}
LFS_EMUBD_TRACE("lfs_emubd_wear -> %"PRIi32, wear);
return wear;
}
int lfs_emubd_setwear(const struct lfs_config *cfg,
lfs_block_t block, lfs_emubd_wear_t wear) {
LFS_EMUBD_TRACE("lfs_emubd_setwear(%p, %"PRIu32", %"PRIi32")",
(void*)cfg, block, wear);
lfs_emubd_t *bd = cfg->context;
// check if block is valid
LFS_ASSERT(block < bd->cfg->erase_count);
// set the wear
lfs_emubd_block_t *b = lfs_emubd_mutblock(cfg, &bd->blocks[block]);
if (!b) {
LFS_EMUBD_TRACE("lfs_emubd_setwear -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
b->wear = wear;
LFS_EMUBD_TRACE("lfs_emubd_setwear -> %d", 0);
return 0;
}
lfs_emubd_spowercycles_t lfs_emubd_powercycles(
const struct lfs_config *cfg) {
LFS_EMUBD_TRACE("lfs_emubd_powercycles(%p)", (void*)cfg);
lfs_emubd_t *bd = cfg->context;
LFS_EMUBD_TRACE("lfs_emubd_powercycles -> %"PRIi32, bd->power_cycles);
return bd->power_cycles;
}
int lfs_emubd_setpowercycles(const struct lfs_config *cfg,
lfs_emubd_powercycles_t power_cycles) {
LFS_EMUBD_TRACE("lfs_emubd_setpowercycles(%p, %"PRIi32")",
(void*)cfg, power_cycles);
lfs_emubd_t *bd = cfg->context;
bd->power_cycles = power_cycles;
LFS_EMUBD_TRACE("lfs_emubd_powercycles -> %d", 0);
return 0;
}
int lfs_emubd_copy(const struct lfs_config *cfg, lfs_emubd_t *copy) {
LFS_EMUBD_TRACE("lfs_emubd_copy(%p, %p)", (void*)cfg, (void*)copy);
lfs_emubd_t *bd = cfg->context;
// lazily copy over our block array
copy->blocks = malloc(bd->cfg->erase_count * sizeof(lfs_emubd_block_t*));
if (!copy->blocks) {
LFS_EMUBD_TRACE("lfs_emubd_copy -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
for (size_t i = 0; i < bd->cfg->erase_count; i++) {
copy->blocks[i] = lfs_emubd_incblock(bd->blocks[i]);
}
// other state
copy->readed = bd->readed;
copy->proged = bd->proged;
copy->erased = bd->erased;
copy->power_cycles = bd->power_cycles;
copy->ooo_block = bd->ooo_block;
copy->ooo_data = lfs_emubd_incblock(bd->ooo_data);
copy->disk = bd->disk;
if (copy->disk) {
copy->disk->rc += 1;
}
copy->cfg = bd->cfg;
LFS_EMUBD_TRACE("lfs_emubd_copy -> %d", 0);
return 0;
}

244
kernel/fs/littlefs/bd/lfs_emubd.h Normal file
View File

@ -0,0 +1,244 @@
/*
* Emulating block device, wraps filebd and rambd while providing a bunch
* of hooks for testing littlefs in various conditions.
*
* Copyright (c) 2022, The littlefs authors.
* Copyright (c) 2017, Arm Limited. All rights reserved.
* SPDX-License-Identifier: BSD-3-Clause
*/
#ifndef LFS_EMUBD_H
#define LFS_EMUBD_H
#include "lfs.h"
#include "lfs_util.h"
#include "bd/lfs_rambd.h"
#include "bd/lfs_filebd.h"
#ifdef __cplusplus
extern "C"
{
#endif
// Block device specific tracing
#ifndef LFS_EMUBD_TRACE
#ifdef LFS_EMUBD_YES_TRACE
#define LFS_EMUBD_TRACE(...) LFS_TRACE(__VA_ARGS__)
#else
#define LFS_EMUBD_TRACE(...)
#endif
#endif
// Mode determining how "bad-blocks" behave during testing. This simulates
// some real-world circumstances such as progs not sticking (prog-noop),
// a readonly disk (erase-noop), and ECC failures (read-error).
//
// Not that read-noop is not allowed. Read _must_ return a consistent (but
// may be arbitrary) value on every read.
typedef enum lfs_emubd_badblock_behavior {
LFS_EMUBD_BADBLOCK_PROGERROR = 0, // Error on prog
LFS_EMUBD_BADBLOCK_ERASEERROR = 1, // Error on erase
LFS_EMUBD_BADBLOCK_READERROR = 2, // Error on read
LFS_EMUBD_BADBLOCK_PROGNOOP = 3, // Prog does nothing silently
LFS_EMUBD_BADBLOCK_ERASENOOP = 4, // Erase does nothing silently
} lfs_emubd_badblock_behavior_t;
// Mode determining how power-loss behaves during testing. For now this
// only supports a noop behavior, leaving the data on-disk untouched.
typedef enum lfs_emubd_powerloss_behavior {
LFS_EMUBD_POWERLOSS_NOOP = 0, // Progs are atomic
LFS_EMUBD_POWERLOSS_OOO = 1, // Blocks are written out-of-order
} lfs_emubd_powerloss_behavior_t;
// Type for measuring read/program/erase operations
typedef uint64_t lfs_emubd_io_t;
typedef int64_t lfs_emubd_sio_t;
// Type for measuring wear
typedef uint32_t lfs_emubd_wear_t;
typedef int32_t lfs_emubd_swear_t;
// Type for tracking power-cycles
typedef uint32_t lfs_emubd_powercycles_t;
typedef int32_t lfs_emubd_spowercycles_t;
// Type for delays in nanoseconds
typedef uint64_t lfs_emubd_sleep_t;
typedef int64_t lfs_emubd_ssleep_t;
// emubd config, this is required for testing
struct lfs_emubd_config {
// Minimum size of a read operation in bytes.
lfs_size_t read_size;
// Minimum size of a program operation in bytes.
lfs_size_t prog_size;
// Size of an erase operation in bytes.
lfs_size_t erase_size;
// Number of erase blocks on the device.
lfs_size_t erase_count;
// 8-bit erase value to use for simulating erases. -1 does not simulate
// erases, which can speed up testing by avoiding the extra block-device
// operations to store the erase value.
int32_t erase_value;
// Number of erase cycles before a block becomes "bad". The exact behavior
// of bad blocks is controlled by badblock_behavior.
uint32_t erase_cycles;
// The mode determining how bad-blocks fail
lfs_emubd_badblock_behavior_t badblock_behavior;
// Number of write operations (erase/prog) before triggering a power-loss.
// power_cycles=0 disables this. The exact behavior of power-loss is
// controlled by a combination of powerloss_behavior and powerloss_cb.
lfs_emubd_powercycles_t power_cycles;
// The mode determining how power-loss affects disk
lfs_emubd_powerloss_behavior_t powerloss_behavior;
// Function to call to emulate power-loss. The exact behavior of power-loss
// is up to the runner to provide.
void (*powerloss_cb)(void*);
// Data for power-loss callback
void *powerloss_data;
// True to track when power-loss could have occured. Note this involves
// heavy memory usage!
bool track_branches;
// Path to file to use as a mirror of the disk. This provides a way to view
// the current state of the block device.
const char *disk_path;
// Artificial delay in nanoseconds, there is no purpose for this other
// than slowing down the simulation.
lfs_emubd_sleep_t read_sleep;
// Artificial delay in nanoseconds, there is no purpose for this other
// than slowing down the simulation.
lfs_emubd_sleep_t prog_sleep;
// Artificial delay in nanoseconds, there is no purpose for this other
// than slowing down the simulation.
lfs_emubd_sleep_t erase_sleep;
};
// A reference counted block
typedef struct lfs_emubd_block {
uint32_t rc;
lfs_emubd_wear_t wear;
uint8_t data[];
} lfs_emubd_block_t;
// Disk mirror
typedef struct lfs_emubd_disk {
uint32_t rc;
int fd;
uint8_t *scratch;
} lfs_emubd_disk_t;
// emubd state
typedef struct lfs_emubd {
// array of copy-on-write blocks
lfs_emubd_block_t **blocks;
// some other test state
lfs_emubd_io_t readed;
lfs_emubd_io_t proged;
lfs_emubd_io_t erased;
lfs_emubd_powercycles_t power_cycles;
lfs_ssize_t ooo_block;
lfs_emubd_block_t *ooo_data;
lfs_emubd_disk_t *disk;
const struct lfs_emubd_config *cfg;
} lfs_emubd_t;
/// Block device API ///
// Create an emulating block device using the geometry in lfs_config
int lfs_emubd_create(const struct lfs_config *cfg,
const struct lfs_emubd_config *bdcfg);
// Clean up memory associated with block device
int lfs_emubd_destroy(const struct lfs_config *cfg);
// Read a block
int lfs_emubd_read(const struct lfs_config *cfg, lfs_block_t block,
lfs_off_t off, void *buffer, lfs_size_t size);
// Program a block
//
// The block must have previously been erased.
int lfs_emubd_prog(const struct lfs_config *cfg, lfs_block_t block,
lfs_off_t off, const void *buffer, lfs_size_t size);
// Erase a block
//
// A block must be erased before being programmed. The
// state of an erased block is undefined.
int lfs_emubd_erase(const struct lfs_config *cfg, lfs_block_t block);
// Sync the block device
int lfs_emubd_sync(const struct lfs_config *cfg);
/// Additional extended API for driving test features ///
// A CRC of a block for debugging purposes
int lfs_emubd_crc(const struct lfs_config *cfg,
lfs_block_t block, uint32_t *crc);
// A CRC of the entire block device for debugging purposes
int lfs_emubd_bdcrc(const struct lfs_config *cfg, uint32_t *crc);
// Get total amount of bytes read
lfs_emubd_sio_t lfs_emubd_readed(const struct lfs_config *cfg);
// Get total amount of bytes programmed
lfs_emubd_sio_t lfs_emubd_proged(const struct lfs_config *cfg);
// Get total amount of bytes erased
lfs_emubd_sio_t lfs_emubd_erased(const struct lfs_config *cfg);
// Manually set amount of bytes read
int lfs_emubd_setreaded(const struct lfs_config *cfg, lfs_emubd_io_t readed);
// Manually set amount of bytes programmed
int lfs_emubd_setproged(const struct lfs_config *cfg, lfs_emubd_io_t proged);
// Manually set amount of bytes erased
int lfs_emubd_seterased(const struct lfs_config *cfg, lfs_emubd_io_t erased);
// Get simulated wear on a given block
lfs_emubd_swear_t lfs_emubd_wear(const struct lfs_config *cfg,
lfs_block_t block);
// Manually set simulated wear on a given block
int lfs_emubd_setwear(const struct lfs_config *cfg,
lfs_block_t block, lfs_emubd_wear_t wear);
// Get the remaining power-cycles
lfs_emubd_spowercycles_t lfs_emubd_powercycles(
const struct lfs_config *cfg);
// Manually set the remaining power-cycles
int lfs_emubd_setpowercycles(const struct lfs_config *cfg,
lfs_emubd_powercycles_t power_cycles);
// Create a copy-on-write copy of the state of this block device
int lfs_emubd_copy(const struct lfs_config *cfg, lfs_emubd_t *copy);
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif

167
kernel/fs/littlefs/bd/lfs_filebd.c Normal file
View File

@ -0,0 +1,167 @@
/*
* Block device emulated in a file
*
* Copyright (c) 2022, The littlefs authors.
* Copyright (c) 2017, Arm Limited. All rights reserved.
* SPDX-License-Identifier: BSD-3-Clause
*/
#include "bd/lfs_filebd.h"
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#ifdef _WIN32
#include <windows.h>
#endif
int lfs_filebd_create(const struct lfs_config *cfg, const char *path,
const struct lfs_filebd_config *bdcfg) {
LFS_FILEBD_TRACE("lfs_filebd_create(%p {.context=%p, "
".read=%p, .prog=%p, .erase=%p, .sync=%p}, "
"\"%s\", "
"%p {.read_size=%"PRIu32", .prog_size=%"PRIu32", "
".erase_size=%"PRIu32", .erase_count=%"PRIu32"})",
(void*)cfg, cfg->context,
(void*)(uintptr_t)cfg->read, (void*)(uintptr_t)cfg->prog,
(void*)(uintptr_t)cfg->erase, (void*)(uintptr_t)cfg->sync,
path,
(void*)bdcfg,
bdcfg->read_size, bdcfg->prog_size, bdcfg->erase_size,
bdcfg->erase_count);
lfs_filebd_t *bd = cfg->context;
bd->cfg = bdcfg;
// open file
#ifdef _WIN32
bd->fd = open(path, O_RDWR | O_CREAT | O_BINARY, 0666);
#else
bd->fd = open(path, O_RDWR | O_CREAT, 0666);
#endif
if (bd->fd < 0) {
int err = -errno;
LFS_FILEBD_TRACE("lfs_filebd_create -> %d", err);
return err;
}
LFS_FILEBD_TRACE("lfs_filebd_create -> %d", 0);
return 0;
}
int lfs_filebd_destroy(const struct lfs_config *cfg) {
LFS_FILEBD_TRACE("lfs_filebd_destroy(%p)", (void*)cfg);
lfs_filebd_t *bd = cfg->context;
int err = close(bd->fd);
if (err < 0) {
err = -errno;
LFS_FILEBD_TRACE("lfs_filebd_destroy -> %d", err);
return err;
}
LFS_FILEBD_TRACE("lfs_filebd_destroy -> %d", 0);
return 0;
}
int lfs_filebd_read(const struct lfs_config *cfg, lfs_block_t block,
lfs_off_t off, void *buffer, lfs_size_t size) {
LFS_FILEBD_TRACE("lfs_filebd_read(%p, "
"0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
(void*)cfg, block, off, buffer, size);
lfs_filebd_t *bd = cfg->context;
// check if read is valid
LFS_ASSERT(block < bd->cfg->erase_count);
LFS_ASSERT(off % bd->cfg->read_size == 0);
LFS_ASSERT(size % bd->cfg->read_size == 0);
LFS_ASSERT(off+size <= bd->cfg->erase_size);
// zero for reproducibility (in case file is truncated)
memset(buffer, 0, size);
// read
off_t res1 = lseek(bd->fd,
(off_t)block*bd->cfg->erase_size + (off_t)off, SEEK_SET);
if (res1 < 0) {
int err = -errno;
LFS_FILEBD_TRACE("lfs_filebd_read -> %d", err);
return err;
}
ssize_t res2 = read(bd->fd, buffer, size);
if (res2 < 0) {
int err = -errno;
LFS_FILEBD_TRACE("lfs_filebd_read -> %d", err);
return err;
}
LFS_FILEBD_TRACE("lfs_filebd_read -> %d", 0);
return 0;
}
int lfs_filebd_prog(const struct lfs_config *cfg, lfs_block_t block,
lfs_off_t off, const void *buffer, lfs_size_t size) {
LFS_FILEBD_TRACE("lfs_filebd_prog(%p, "
"0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
(void*)cfg, block, off, buffer, size);
lfs_filebd_t *bd = cfg->context;
// check if write is valid
LFS_ASSERT(block < bd->cfg->erase_count);
LFS_ASSERT(off % bd->cfg->prog_size == 0);
LFS_ASSERT(size % bd->cfg->prog_size == 0);
LFS_ASSERT(off+size <= bd->cfg->erase_size);
// program data
off_t res1 = lseek(bd->fd,
(off_t)block*bd->cfg->erase_size + (off_t)off, SEEK_SET);
if (res1 < 0) {
int err = -errno;
LFS_FILEBD_TRACE("lfs_filebd_prog -> %d", err);
return err;
}
ssize_t res2 = write(bd->fd, buffer, size);
if (res2 < 0) {
int err = -errno;
LFS_FILEBD_TRACE("lfs_filebd_prog -> %d", err);
return err;
}
LFS_FILEBD_TRACE("lfs_filebd_prog -> %d", 0);
return 0;
}
int lfs_filebd_erase(const struct lfs_config *cfg, lfs_block_t block) {
LFS_FILEBD_TRACE("lfs_filebd_erase(%p, 0x%"PRIx32" (%"PRIu32"))",
(void*)cfg, block, ((lfs_filebd_t*)cfg->context)->cfg->erase_size);
lfs_filebd_t *bd = cfg->context;
// check if erase is valid
LFS_ASSERT(block < bd->cfg->erase_count);
// erase is a noop
(void)block;
LFS_FILEBD_TRACE("lfs_filebd_erase -> %d", 0);
return 0;
}
int lfs_filebd_sync(const struct lfs_config *cfg) {
LFS_FILEBD_TRACE("lfs_filebd_sync(%p)", (void*)cfg);
// file sync
lfs_filebd_t *bd = cfg->context;
#ifdef _WIN32
int err = FlushFileBuffers((HANDLE) _get_osfhandle(bd->fd)) ? 0 : -1;
#else
int err = fsync(bd->fd);
#endif
if (err) {
err = -errno;
LFS_FILEBD_TRACE("lfs_filebd_sync -> %d", 0);
return err;
}
LFS_FILEBD_TRACE("lfs_filebd_sync -> %d", 0);
return 0;
}

82
kernel/fs/littlefs/bd/lfs_filebd.h Normal file
View File

@ -0,0 +1,82 @@
/*
* Block device emulated in a file
*
* Copyright (c) 2022, The littlefs authors.
* Copyright (c) 2017, Arm Limited. All rights reserved.
* SPDX-License-Identifier: BSD-3-Clause
*/
#ifndef LFS_FILEBD_H
#define LFS_FILEBD_H
#include "lfs.h"
#include "lfs_util.h"
#ifdef __cplusplus
extern "C"
{
#endif
// Block device specific tracing
#ifndef LFS_FILEBD_TRACE
#ifdef LFS_FILEBD_YES_TRACE
#define LFS_FILEBD_TRACE(...) LFS_TRACE(__VA_ARGS__)
#else
#define LFS_FILEBD_TRACE(...)
#endif
#endif
// filebd config
struct lfs_filebd_config {
// Minimum size of a read operation in bytes.
lfs_size_t read_size;
// Minimum size of a program operation in bytes.
lfs_size_t prog_size;
// Size of an erase operation in bytes.
lfs_size_t erase_size;
// Number of erase blocks on the device.
lfs_size_t erase_count;
};
// filebd state
typedef struct lfs_filebd {
int fd;
const struct lfs_filebd_config *cfg;
} lfs_filebd_t;
// Create a file block device
int lfs_filebd_create(const struct lfs_config *cfg, const char *path,
const struct lfs_filebd_config *bdcfg);
// Clean up memory associated with block device
int lfs_filebd_destroy(const struct lfs_config *cfg);
// Read a block
int lfs_filebd_read(const struct lfs_config *cfg, lfs_block_t block,
lfs_off_t off, void *buffer, lfs_size_t size);
// Program a block
//
// The block must have previously been erased.
int lfs_filebd_prog(const struct lfs_config *cfg, lfs_block_t block,
lfs_off_t off, const void *buffer, lfs_size_t size);
// Erase a block
//
// A block must be erased before being programmed. The
// state of an erased block is undefined.
int lfs_filebd_erase(const struct lfs_config *cfg, lfs_block_t block);
// Sync the block device
int lfs_filebd_sync(const struct lfs_config *cfg);
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif

118
kernel/fs/littlefs/bd/lfs_rambd.c Normal file
View File

@ -0,0 +1,118 @@
/*
* Block device emulated in RAM
*
* Copyright (c) 2022, The littlefs authors.
* Copyright (c) 2017, Arm Limited. All rights reserved.
* SPDX-License-Identifier: BSD-3-Clause
*/
#include "bd/lfs_rambd.h"
int lfs_rambd_create(const struct lfs_config *cfg,
const struct lfs_rambd_config *bdcfg) {
LFS_RAMBD_TRACE("lfs_rambd_create(%p {.context=%p, "
".read=%p, .prog=%p, .erase=%p, .sync=%p}, "
"%p {.read_size=%"PRIu32", .prog_size=%"PRIu32", "
".erase_size=%"PRIu32", .erase_count=%"PRIu32", "
".buffer=%p})",
(void*)cfg, cfg->context,
(void*)(uintptr_t)cfg->read, (void*)(uintptr_t)cfg->prog,
(void*)(uintptr_t)cfg->erase, (void*)(uintptr_t)cfg->sync,
(void*)bdcfg,
bdcfg->read_size, bdcfg->prog_size, bdcfg->erase_size,
bdcfg->erase_count, bdcfg->buffer);
lfs_rambd_t *bd = cfg->context;
bd->cfg = bdcfg;
// allocate buffer?
if (bd->cfg->buffer) {
bd->buffer = bd->cfg->buffer;
} else {
bd->buffer = lfs_malloc(bd->cfg->erase_size * bd->cfg->erase_count);
if (!bd->buffer) {
LFS_RAMBD_TRACE("lfs_rambd_create -> %d", LFS_ERR_NOMEM);
return LFS_ERR_NOMEM;
}
}
// zero for reproducibility
memset(bd->buffer, 0, bd->cfg->erase_size * bd->cfg->erase_count);
LFS_RAMBD_TRACE("lfs_rambd_create -> %d", 0);
return 0;
}
int lfs_rambd_destroy(const struct lfs_config *cfg) {
LFS_RAMBD_TRACE("lfs_rambd_destroy(%p)", (void*)cfg);
// clean up memory
lfs_rambd_t *bd = cfg->context;
if (!bd->cfg->buffer) {
lfs_free(bd->buffer);
}
LFS_RAMBD_TRACE("lfs_rambd_destroy -> %d", 0);
return 0;
}
int lfs_rambd_read(const struct lfs_config *cfg, lfs_block_t block,
lfs_off_t off, void *buffer, lfs_size_t size) {
LFS_RAMBD_TRACE("lfs_rambd_read(%p, "
"0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
(void*)cfg, block, off, buffer, size);
lfs_rambd_t *bd = cfg->context;
// check if read is valid
LFS_ASSERT(block < bd->cfg->erase_count);
LFS_ASSERT(off % bd->cfg->read_size == 0);
LFS_ASSERT(size % bd->cfg->read_size == 0);
LFS_ASSERT(off+size <= bd->cfg->erase_size);
// read data
memcpy(buffer, &bd->buffer[block*bd->cfg->erase_size + off], size);
LFS_RAMBD_TRACE("lfs_rambd_read -> %d", 0);
return 0;
}
int lfs_rambd_prog(const struct lfs_config *cfg, lfs_block_t block,
lfs_off_t off, const void *buffer, lfs_size_t size) {
LFS_RAMBD_TRACE("lfs_rambd_prog(%p, "
"0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
(void*)cfg, block, off, buffer, size);
lfs_rambd_t *bd = cfg->context;
// check if write is valid
LFS_ASSERT(block < bd->cfg->erase_count);
LFS_ASSERT(off % bd->cfg->prog_size == 0);
LFS_ASSERT(size % bd->cfg->prog_size == 0);
LFS_ASSERT(off+size <= bd->cfg->erase_size);
// program data
memcpy(&bd->buffer[block*bd->cfg->erase_size + off], buffer, size);
LFS_RAMBD_TRACE("lfs_rambd_prog -> %d", 0);
return 0;
}
int lfs_rambd_erase(const struct lfs_config *cfg, lfs_block_t block) {
LFS_RAMBD_TRACE("lfs_rambd_erase(%p, 0x%"PRIx32" (%"PRIu32"))",
(void*)cfg, block, ((lfs_rambd_t*)cfg->context)->cfg->erase_size);
lfs_rambd_t *bd = cfg->context;
// check if erase is valid
LFS_ASSERT(block < bd->cfg->erase_count);
// erase is a noop
(void)block;
LFS_RAMBD_TRACE("lfs_rambd_erase -> %d", 0);
return 0;
}
int lfs_rambd_sync(const struct lfs_config *cfg) {
LFS_RAMBD_TRACE("lfs_rambd_sync(%p)", (void*)cfg);
// sync is a noop
(void)cfg;
LFS_RAMBD_TRACE("lfs_rambd_sync -> %d", 0);
return 0;
}

85
kernel/fs/littlefs/bd/lfs_rambd.h Normal file
View File

@ -0,0 +1,85 @@
/*
* Block device emulated in RAM
*
* Copyright (c) 2022, The littlefs authors.
* Copyright (c) 2017, Arm Limited. All rights reserved.
* SPDX-License-Identifier: BSD-3-Clause
*/
#ifndef LFS_RAMBD_H
#define LFS_RAMBD_H
#include "lfs.h"
#include "lfs_util.h"
#ifdef __cplusplus
extern "C"
{
#endif
// Block device specific tracing
#ifndef LFS_RAMBD_TRACE
#ifdef LFS_RAMBD_YES_TRACE
#define LFS_RAMBD_TRACE(...) LFS_TRACE(__VA_ARGS__)
#else
#define LFS_RAMBD_TRACE(...)
#endif
#endif
// rambd config
struct lfs_rambd_config {
// Minimum size of a read operation in bytes.
lfs_size_t read_size;
// Minimum size of a program operation in bytes.
lfs_size_t prog_size;
// Size of an erase operation in bytes.
lfs_size_t erase_size;
// Number of erase blocks on the device.
lfs_size_t erase_count;
// Optional statically allocated buffer for the block device.
void *buffer;
};
// rambd state
typedef struct lfs_rambd {
uint8_t *buffer;
const struct lfs_rambd_config *cfg;
} lfs_rambd_t;
// Create a RAM block device
int lfs_rambd_create(const struct lfs_config *cfg,
const struct lfs_rambd_config *bdcfg);
// Clean up memory associated with block device
int lfs_rambd_destroy(const struct lfs_config *cfg);
// Read a block
int lfs_rambd_read(const struct lfs_config *cfg, lfs_block_t block,
lfs_off_t off, void *buffer, lfs_size_t size);
// Program a block
//
// The block must have previously been erased.
int lfs_rambd_prog(const struct lfs_config *cfg, lfs_block_t block,
lfs_off_t off, const void *buffer, lfs_size_t size);
// Erase a block
//
// A block must be erased before being programmed. The
// state of an erased block is undefined.
int lfs_rambd_erase(const struct lfs_config *cfg, lfs_block_t block);
// Sync the block device
int lfs_rambd_sync(const struct lfs_config *cfg);
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif