A light-weight littlefs interface library for Raspberry Pi Pico C SDK.
This software is under GPL license, while "littlefs" is subject to its own license.
Some projects using this library:
This is meant to be included as a submodule in a Pico C SDK project.
First add submodule under your project directory:
$ mkdir libs
$ cd libs
$ git submodule add https://github.com/tjko/pico-lfs.git
Then in CMakeLists.txt add following:
# Include pico-lfs library
add_subdirectory(libs/pico-lfs)
...
target_link_libraries(myproject PRIVATE pico-lfs)
target_compile_definitions(myproject PRIVATE
LFS_THREADSAFE=1
LFS_NO_DEBUG=1
)
To use this library you must decide location and size for the littlefs filesystem in the flash memory.
This example assumes using last 256kb of the flash memory:
#include "pico_lfs.h"
#define FS_SIZE (256 * 1024)
static struct lfs_config *lfs_cfg;
static lfs_t lfs;
...
int main()
{
lfs_file_t file;
/* Near the beginning of your program initialize LFS */
lfs_cfg = pico_lfs_init(PICO_FLASH_SIZE_BYTES - FS_SIZE, FS_SIZE);
if (!lfs_cfg)
panic("out of memory");
/* Format new FS if needed */
int err = lfs_mount(&lfs, lfs_cfg);
if (err != LFS_ERR_OK) {
/* Initialize new filesystem */
err = lfs_format(&lfs, lfs_cfg);
if (err != LFS_ERR_OK)
panic("failed to format filesystem");
err = lfs_mount(&lfs, lfs_cfg);
if (err != LFS_ERR_OK)
panic("failed to mount new filesystem");
}
...
}
After lfs is "mounted" then it can be used as normal via standard littlefs functions... (see littlefs documentation)
If program using this library is using pico_multicore library, it should get detected automatically
(as LIB_PICO_MULTICORE should be defined during compilation).
NOTE, when multicore support is enabled flash programming and erase functions will always make calls to multicore_lockout_start_blocking() and multicore_lockout_end_blocking() as needed.
It is important to have initialized second core and to allow it to be paused by the other cored, before trying to do any "write" operations on the littlefs.
void core1_main()
{
multicore_lockout_victim_init();
...
}
void main()
{
...
multicore_launch_core1(core1_main);
...
/* Don't write to littlefs until after second core is initialized... */
...
}
This library implements I/O functions for littlefs to operate on built-in flash on Pico.
This library provides only functions to initialize littlefs and another function to free the filesystem data structures (application only briefly needs filesystem access, etc).
/* Initialize LFS configuration.
This dynamically allocates memory for the configuration.
Parameters:
offset = offset in flash memory (must be aligned on 4K page size)
size = size of the filesystem (must be multiple of 4K page size)
*/
struct lfs_config* pico_lfs_init(size_t offset, size_t size);
/* Release LFS configuration (if needed).
lfs_unmount() should be called before calling this.
*/
void pico_lfs_destroy(struct lfs_config *cfg);