nrf: Add LittleFS support to nrf52840.

To be amended / split / squashed.

LittleFS can be enabled by MICROPY_VFS_LFS1 or MICROPY_VFS_LFS2.

Added support for setting MICROPY_VFS_FAT=0.

Added support for configuring file system size rom makefile invocation.
New parameter `FS_SIZE` can be used to adjust the size of requested partition
for internal flash storage. For example `FS_SIZE=0x40000` or `FS_SIZE=256K`.

ports/nrf/Makefile

@@ -38,12 +38,13 @@ endif
 # qstr definitions (must come before including py.mk)
 QSTR_DEFS = qstrdefsport.h $(BUILD)/pins_qstr.h
 
+MICROPY_VFS_FAT ?= 0
+
 # include py core make definitions
 include ../../py/py.mk
 
 GIT_SUBMODULES = lib/nrfx lib/tinyusb
 
-MICROPY_VFS_FAT ?= 0
 MPY_CROSS = ../../mpy-cross/mpy-cross
 MPY_TOOL = ../../tools/mpy-tool.py
 
@@ -118,6 +119,9 @@ LDFLAGS = $(CFLAGS)
 LDFLAGS += -Xlinker -Map=$(@:.elf=.map)
 LDFLAGS += -mthumb -mabi=aapcs $(addprefix -T,$(LD_FILES)) -L boards/
 
+FS_SIZE ?= 256K
+LDFLAGS += -Wl,'--defsym=_fs_size=$(FS_SIZE)'
+
 #Debugging/Optimization
 ifeq ($(DEBUG), 1)
 #ASMFLAGS += -g -gtabs+

ports/nrf/README.md

@@ -114,6 +114,34 @@ For example:
 
      make BOARD=pca10040 MICROPY_VFS_FAT=1
 
+## Enable MICROPY_VFS_LFS1 or MICROPY_VFS_LFS2
+
+In order to enable `littlefs` as device flash filesystem, `MICROPY_VFS_LFS1`
+or `MICROPY_VFS_LFS2` can be set. This will be in addition of setting
+`MICROPY_VFS` in mpconfigport.h or mpconfigboard.h.
+
+For example:
+
+    make BOARD=pca10056 MICROPY_VFS_LFS=2
+
+## Set file system size
+
+The size of the file system on the internal flash is configured by the linker
+script parameter `_fs_size`. This can either be overriden by the linker script
+or dynamically through the makefile. By seting a value to the `FS_SIZE`.
+The number will be passed directly to the linker scripts in order to calculate
+the start and end of the file system. Note that the parameter value must be in
+linker script syntax as it is passed directly.
+
+For example, if we want to override the default 64K file system size set by the
+linker scripts to use 256K instead:
+
+    make BOARD=pca10056 MICROPY_VFS_LFS2=1 FS_SIZE=256K
+
+Also note that changing this size between builds might cause loss of files
+present from a previous firmware as it will format the file system due to a new
+location.
+
 ## Target Boards and Make Flags
 
 Target Board (BOARD) | Bluetooth Stack (SD)    | Bluetooth Support      | Flash Util

ports/nrf/boards/nrf52840_1M_256k.ld

@@ -4,7 +4,6 @@
 
 _flash_size = 1M;
 _ram_size   = 256K;
-_fs_size    = 256K;
 /* produce a link error if there is not this amount of RAM for these sections */
 _stack_size = 8K;
 _minimum_heap_size = 128K;

ports/nrf/boards/pca10056/mpconfigboard.h

@@ -41,6 +41,7 @@
 #define MICROPY_VFS                 (1)
 #define MICROPY_HW_ENABLE_STORAGE   (1)
 #define MICROPY_MBFS                (0)
+#define MICROPY_HW_BDEV_READBLOCKS_EXT (1)
 
 #define MICROPY_HW_HAS_LED          (1)
 #define MICROPY_HW_LED_COUNT        (4)

ports/nrf/main.c

@@ -128,8 +128,9 @@ STATIC int vfs_mount_and_chdir(mp_obj_t bdev, mp_obj_t mount_point) {
 }
 
 int factory_reset_filesystem(void) {
+#if MICROPY_VFS_FAT
     fs_user_mount_t vfs;
-    flash_init_vfs(&vfs);
+    flash_init_vfs_fat(&vfs);
     uint8_t working_buf[FF_MAX_SS];
     FRESULT res = f_mkfs(&vfs.fatfs, FM_FAT | FM_SFD, 0, working_buf, sizeof(working_buf));
     if (res != FR_OK) {
@@ -139,6 +140,19 @@ int factory_reset_filesystem(void) {
 
     // Set label
     f_setlabel(&vfs.fatfs, MICROPY_HW_FLASH_FS_LABEL);
+#endif
+#if MICROPY_VFS_LFS1
+    // Setup builtin flash
+    do_str("import uos, nrf\n" \
+           "uos.VfsLfs1.mkfs(nrf.flashbdev)",
+           MP_PARSE_FILE_INPUT);
+#endif
+#if MICROPY_VFS_LFS2
+    // Setup builtin flash
+    do_str("import uos, nrf\n" \
+           "uos.VfsLfs2.mkfs(nrf.flashbdev)",
+           MP_PARSE_FILE_INPUT);
+#endif
     return 0;
 }
 #endif
@@ -217,7 +231,7 @@ int main(int argc, char **argv) {
     mp_obj_t mount_point = MP_OBJ_NEW_QSTR(MP_QSTR__slash_flash);
     int ret = vfs_mount_and_chdir((mp_obj_t)&nrf_flashbdev_obj, mount_point);
 
-    if (ret == -MP_ENODEV) {
+    if ((ret == -MP_ENODEV) || (ret == -MP_EIO)) {
         ret = factory_reset_filesystem();
         if (ret == 0) {
             ret = vfs_mount_and_chdir((mp_obj_t)&nrf_flashbdev_obj, mount_point);

ports/nrf/modules/uos/modnrf.c

@@ -28,6 +28,7 @@
 #include <stdio.h>
 #include <stdint.h>
 #include "py/runtime.h"
+#include "py/mperrno.h"
 #include "mpconfigboard.h"
 
 #if MICROPY_HW_ENABLE_STORAGE
@@ -41,6 +42,7 @@ extern byte _fs_end[];
 
 #define FLASH_BLOCK_START (((uint32_t)_fs_start + (FLASH_PAGESIZE-1)) / FLASH_PAGESIZE)
 
+#if MICROPY_VFS_FAT
 static int nrf_flashbdev_readblocks_native(uint8_t *buf, size_t block_num, size_t num_blocks) {
     mp_int_t address = (FLASH_BLOCK_START + block_num) * FLASH_PAGESIZE;
     byte *p = (byte*)address;
@@ -61,41 +63,51 @@ static int nrf_flashbdev_writeblocks_native(const uint8_t *buf, size_t block_num
     }
     return 0;
 }
+#endif
 
-mp_obj_t nrf_flashbdev_readblocks(mp_obj_t self_in, mp_obj_t n_in, mp_obj_t buf_in) {
-
-    mp_int_t n = mp_obj_get_int(n_in);
+mp_obj_t nrf_flashbdev_readblocks(size_t n_args, const mp_obj_t * args) {
+    uint32_t block_num = mp_obj_get_int(args[1]);
     mp_buffer_info_t bufinfo;
-    mp_get_buffer_raise(buf_in, &bufinfo, MP_BUFFER_WRITE);
+    mp_get_buffer_raise(args[2], &bufinfo, MP_BUFFER_WRITE);
+
+    mp_int_t address = (FLASH_BLOCK_START + block_num) * FLASH_PAGESIZE;
+
+    #if defined(MICROPY_HW_BDEV_READBLOCKS_EXT)
+    if (n_args == 4) {
+        uint32_t offset = mp_obj_get_int(args[3]);
+        address += offset;
+    }
+    #endif
 
-    mp_int_t address = (FLASH_BLOCK_START + n) * FLASH_PAGESIZE;
     byte *buf = bufinfo.buf;
-    byte *p = (byte*)address;
-    for (int i=0; i<bufinfo.len; i++) {
+    byte *p = (byte *)address;
+    for (int i = 0; i < bufinfo.len; i++) {
         buf[i] = p[i];
     }
+
     return MP_OBJ_NEW_SMALL_INT(0);
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_3(nrf_flashbdev_readblocks_obj, nrf_flashbdev_readblocks);
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(nrf_flashbdev_readblocks_obj, 3, 4, nrf_flashbdev_readblocks);
 
-mp_obj_t nrf_flashbdev_writeblocks(mp_obj_t self_in, mp_obj_t n_in, mp_obj_t buf_in) {
-    mp_int_t n = mp_obj_get_int(n_in);
+mp_obj_t nrf_flashbdev_writeblocks(size_t n_args, const mp_obj_t * args) {
+    uint32_t block_num = mp_obj_get_int(args[1]);
     mp_buffer_info_t bufinfo;
-    mp_get_buffer_raise(buf_in, &bufinfo, MP_BUFFER_READ);
+    mp_get_buffer_raise(args[2], &bufinfo, MP_BUFFER_WRITE);
 
-    mp_int_t address = (FLASH_BLOCK_START + n) * FLASH_PAGESIZE;
-    if (address & 0x3 || bufinfo.len & 0x3) {
-        mp_raise_ValueError("invalid address or buffer length");
-    }
+    mp_int_t address = (FLASH_BLOCK_START + block_num) * FLASH_PAGESIZE;
 
-    flash_page_erase(address);
+    #if defined(MICROPY_HW_BDEV_READBLOCKS_EXT)
+    if (n_args == 4) {
+        uint32_t offset = mp_obj_get_int(args[3]);
+        address += offset;
+    }
+    #endif
 
     flash_write_bytes(address, bufinfo.buf, bufinfo.len);
 
     return MP_OBJ_NEW_SMALL_INT(0);
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_3(nrf_flashbdev_writeblocks_obj, nrf_flashbdev_writeblocks);
-
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(nrf_flashbdev_writeblocks_obj, 3, 4, nrf_flashbdev_writeblocks);
 
 mp_obj_t nrf_flashbdev_ioctl(mp_obj_t self_in, mp_obj_t op_in, mp_obj_t arg_in) {
     mp_int_t op = mp_obj_get_int(op_in);
@@ -123,6 +135,14 @@ mp_obj_t nrf_flashbdev_ioctl(mp_obj_t self_in, mp_obj_t op_in, mp_obj_t arg_in)
         }
 
         case MP_BLOCKDEV_IOCTL_BLOCK_ERASE: {
+            mp_int_t block_num = mp_obj_get_int(arg_in);
+            mp_int_t address = (FLASH_BLOCK_START + block_num) * FLASH_PAGESIZE;
+
+            if ((address & 0x3) || (address % FLASH_PAGESIZE != 0)) {
+                return MP_OBJ_NEW_SMALL_INT(-MP_EIO);
+            }
+
+            flash_page_erase(address);
             return MP_OBJ_NEW_SMALL_INT(0);
         }
 
@@ -164,7 +184,8 @@ const mp_obj_module_t nrf_module = {
     .globals = (mp_obj_dict_t*)&nrf_module_globals,
 };
 
-void flash_init_vfs(fs_user_mount_t *vfs) {
+#if MICROPY_VFS_FAT
+void flash_init_vfs_fat(fs_user_mount_t *vfs) {
     vfs->base.type = &mp_fat_vfs_type;
 
     vfs->blockdev.flags |= MP_BLOCKDEV_FLAG_HAVE_IOCTL;
@@ -185,5 +206,6 @@ void flash_init_vfs(fs_user_mount_t *vfs) {
     vfs->blockdev.u.ioctl[0] = MP_OBJ_FROM_PTR(&nrf_flashbdev_ioctl_obj);
     vfs->blockdev.u.ioctl[1] = MP_OBJ_FROM_PTR(&nrf_flashbdev_obj);
 }
+#endif
 
 #endif // MICROPY_PY_NRF

ports/nrf/modules/uos/modnrf.h

@@ -37,6 +37,6 @@ typedef struct {
 
 extern const mp_obj_type_t nrf_flashbdev_obj;
 
-void flash_init_vfs(fs_user_mount_t *vfs);
+void flash_init_vfs_fat(fs_user_mount_t *vfs);
 
 #endif // MODNRF_H__

ports/nrf/modules/uos/moduos.c

@@ -36,6 +36,7 @@
 #include "modules/uos/microbitfs.h"
 #include "extmod/vfs.h"
 #include "extmod/vfs_fat.h"
+#include "extmod/vfs_lfs.h"
 #include "genhdr/mpversion.h"
 //#include "timeutils.h"
 #include "uart.h"
@@ -87,10 +88,12 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_0(os_uname_obj, os_uname);
 /// \function sync()
 /// Sync all filesystems.
 STATIC mp_obj_t os_sync(void) {
+    #if MICROPY_VFS_FAT
     for (mp_vfs_mount_t *vfs = MP_STATE_VM(vfs_mount_table); vfs != NULL; vfs = vfs->next) {
         // this assumes that vfs->obj is fs_user_mount_t with block device functions
         disk_ioctl(MP_OBJ_TO_PTR(vfs->obj), CTRL_SYNC, NULL);
     }
+    #endif
     return mp_const_none;
 }
 MP_DEFINE_CONST_FUN_OBJ_0(mod_os_sync_obj, os_sync);
@@ -176,8 +179,16 @@ STATIC const mp_rom_map_elem_t os_module_globals_table[] = {
 #if MICROPY_VFS
     { MP_ROM_QSTR(MP_QSTR_mount), MP_ROM_PTR(&mp_vfs_mount_obj) },
     { MP_ROM_QSTR(MP_QSTR_umount), MP_ROM_PTR(&mp_vfs_umount_obj) },
+#if MICROPY_VFS_FAT
     { MP_ROM_QSTR(MP_QSTR_VfsFat), MP_ROM_PTR(&mp_fat_vfs_type) },
 #endif
+#if MICROPY_VFS_LFS1
+    { MP_ROM_QSTR(MP_QSTR_VfsLfs1), MP_ROM_PTR(&mp_type_vfs_lfs1) },
+#endif
+#if MICROPY_VFS_LFS2
+    { MP_ROM_QSTR(MP_QSTR_VfsLfs2), MP_ROM_PTR(&mp_type_vfs_lfs2) },
+#endif
+#endif
 };
 
 STATIC MP_DEFINE_CONST_DICT(os_module_globals, os_module_globals_table);