Merge tag 'v1.9.1'2.0.0-alpha.0

Fixes for stmhal USB mass storage, lwIP bindings and VFS regressions

This release provides an important fix for the USB mass storage device in
the stmhal port by implementing the SCSI SYNCHRONIZE_CACHE command, which
is now require by some Operating Systems.  There are also fixes for the
lwIP bindings to improve non-blocking sockets and error codes.  The VFS has
some regressions fixed including the ability to statvfs the root.

All changes are listed below.

py core:
- modbuiltins: add core-provided version of input() function
- objstr: catch case of negative "maxsplit" arg to str.rsplit()
- persistentcode: allow to compile with complex numbers disabled
- objstr: allow to compile with obj-repr D, and unicode disabled
- modsys: allow to compile with obj-repr D and PY_ATTRTUPLE disabled
- provide mp_decode_uint_skip() to help reduce stack usage
- makeqstrdefs.py: make script run correctly with Python 2.6
- objstringio: if created from immutable object, follow copy on write policy

extmod:
- modlwip: connect: for non-blocking mode, return EINPROGRESS
- modlwip: fix error codes for duplicate calls to connect()
- modlwip: accept: fix error code for non-blocking mode
- vfs: allow to statvfs the root directory
- vfs: allow "buffering" and "encoding" args to VFS's open()
- modframebuf: fix signed/unsigned comparison pendantic warning

lib:
- libm: use isfinite instead of finitef, for C99 compatibility
- utils/interrupt_char: remove support for KBD_EXCEPTION disabled

tests:
- basics/string_rsplit: add tests for negative "maxsplit" argument
- float: convert "sys.exit()" to "raise SystemExit"
- float/builtin_float_minmax: PEP8 fixes
- basics: convert "sys.exit()" to "raise SystemExit"
- convert remaining "sys.exit()" to "raise SystemExit"

unix port:
- convert to use core-provided version of built-in import()
- Makefile: replace references to make with $(MAKE)

windows port:
- convert to use core-provided version of built-in import()

qemu-arm port:
- Makefile: adjust object-file lists to get correct dependencies
- enable micropython.mem_*() functions to allow more tests

stmhal port:
- boards: enable DAC for NUCLEO_F767ZI board
- add support for NUCLEO_F446RE board
- pass USB handler as parameter to allow more than one USB handler
- usb: use local USB handler variable in Start-of-Frame handler
- usb: make state for USB device private to top-level USB driver
- usbdev: for MSC implement SCSI SYNCHRONIZE_CACHE command
- convert from using stmhal's input() to core provided version

cc3200 port:
- convert from using stmhal's input() to core provided version

teensy port:
- convert from using stmhal's input() to core provided version

esp8266 port:
- Makefile: replace references to make with $(MAKE)
- Makefile: add clean-modules target
- convert from using stmhal's input() to core provided version

zephyr port:
- modusocket: getaddrinfo: Fix mp_obj_len() usage
- define MICROPY_PY_SYS_PLATFORM (to "zephyr")
- machine_pin: use native Zephyr types for Zephyr API calls

docs:
- machine.Pin: remove out_value() method
- machine.Pin: add on() and off() methods
- esp8266: consistently replace Pin.high/low methods with .on/off
- esp8266/quickref: polish Pin.on()/off() examples
- network: move confusingly-named cc3200 Server class to its reference
- uos: deconditionalize, remove minor port-specific details
- uos: move cc3200 port legacy VFS mounting functions to its ref doc
- machine: sort machine classes in logical order, not alphabetically
- network: first step to describe standard network class interface

examples:
- embedding: use core-provided KeyboardInterrupt object

13 files changed, 117 insertions, 386 deletions

diff --git a/atmel-samd/Makefile b/atmel-samd/Makefile
index fbd89cc5a..43312fc56 100644
--- a/atmel-samd/Makefile
+++ b/atmel-samd/Makefile
@@ -125,7 +125,7 @@ CFLAGS_CORTEX_M0 = \
 	-DCIRCUITPY_CANARY_WORD=0xADAF00 \
 	-DCIRCUITPY_SAFE_RESTART_WORD=0xDEADBEEF \
 	--param max-inline-insns-single=500
-CFLAGS = $(INC) -Wall -Werror -std=gnu11 -nostdlib $(CFLAGS_CORTEX_M0) $(COPT)
+CFLAGS = $(INC) -Wall -Werror -std=gnu11 -nostdlib $(CFLAGS_CORTEX_M0) $(CFLAGS_MOD) $(COPT)
 
 #Debugging/Optimization
 # TODO(tannewt): Figure out what NDEBUG does. Adding it to the debug build
@@ -184,7 +184,6 @@ SRC_C = \
 	access_vfs.c \
 	autoreload.c \
 	background.c \
-	builtin_open.c \
 	fatfs_port.c \
 	flash_api.c \
 	main.c \
@@ -213,17 +212,15 @@ SRC_C = \
 	boards/$(BOARD)/board.c \
 	boards/$(BOARD)/pins.c \
 	freetouch/adafruit_ptc.c \
-	lib/fatfs/ff.c \
-	lib/fatfs/option/ccsbcs.c \
+	lib/oofatfs/ff.c \
+	lib/oofatfs/option/ccsbcs.c \
 	lib/timeutils/timeutils.c \
 	lib/utils/buffer_helper.c \
 	lib/utils/context_manager_helpers.c \
 	lib/utils/interrupt_char.c \
 	lib/utils/pyexec.c \
-	lib/utils/pyhelp.c \
 	lib/utils/stdout_helpers.c \
 	lib/libc/string0.c \
-	lib/mp-readline/builtin_input.c \
 	lib/mp-readline/readline.c
 
 STM_SRC_C = $(addprefix stmhal/,\
@@ -261,14 +258,14 @@ SRC_COMMON_HAL = \
 SRC_BINDINGS_ENUMS = \
 	digitalio/Direction.c \
 	digitalio/DriveMode.c \
-	digitalio/Pull.c
+	digitalio/Pull.c \
+	help.c
 
 SRC_COMMON_HAL_EXPANDED = $(addprefix shared-bindings/, $(SRC_COMMON_HAL)) \
                           $(addprefix shared-bindings/, $(SRC_BINDINGS_ENUMS)) \
                           $(addprefix common-hal/, $(SRC_COMMON_HAL))
 
 SRC_SHARED_MODULE = \
-	help.c \
 	bitbangio/__init__.c \
 	bitbangio/I2C.c \
 	bitbangio/OneWire.c \
diff --git a/atmel-samd/access_vfs.c b/atmel-samd/access_vfs.c
index ecdc94e44..72b56526b 100644
--- a/atmel-samd/access_vfs.c
+++ b/atmel-samd/access_vfs.c
@@ -30,8 +30,11 @@
 #include "autoreload.h"
 
 #include "asf/common/services/usb/class/msc/device/udi_msc.h"
-#include "extmod/fsusermount.h"
-#include "lib/fatfs/diskio.h"
+#include "extmod/vfs.h"
+#include "extmod/vfs_fat.h"
+#include "lib/oofatfs/ff.h"
+#include "lib/oofatfs/diskio.h"
+#include "lib/oofatfs/ffconf.h"
 #include "py/mpconfig.h"
 #include "py/mphal.h"
 #include "py/mpstate.h"
@@ -47,15 +50,14 @@
 //!   An error occurred          ->    CTRL_FAIL
 Ctrl_status vfs_test_unit_ready(void)
 {
-    if (VFS_INDEX >= MP_ARRAY_SIZE(MP_STATE_PORT(fs_user_mount))) {
-        return CTRL_FAIL;
-    }
-    DSTATUS status = disk_status(VFS_INDEX);
-    if (status == STA_NOINIT) {
-        return CTRL_NO_PRESENT;
+    mp_vfs_mount_t* current_mount = MP_STATE_VM(vfs_mount_table);
+    for (uint8_t i = 0; current_mount != NULL; i++) {
+        if (i == VFS_INDEX) {
+            return CTRL_GOOD;
+        }
+        current_mount = current_mount->next;
     }
-
-    return CTRL_GOOD;
+    return CTRL_NO_PRESENT;
 }
 
 //! This function returns the address of the last valid sector
@@ -81,13 +83,17 @@ Ctrl_status vfs_read_capacity(uint32_t *last_valid_sector)
 //!
 bool vfs_wr_protect(void)
 {
-    if (VFS_INDEX >= MP_ARRAY_SIZE(MP_STATE_PORT(fs_user_mount))) {
-        return true;
+    mp_vfs_mount_t* current_mount = MP_STATE_VM(vfs_mount_table);
+    for (uint8_t i = 0; current_mount != NULL; i++) {
+        if (i == VFS_INDEX) {
+            break;
+        }
+        current_mount = current_mount->next;
     }
-    fs_user_mount_t *vfs = MP_STATE_PORT(fs_user_mount)[VFS_INDEX];
-    if (vfs == NULL) {
+    if (current_mount == NULL) {
         return true;
     }
+    fs_user_mount_t *vfs = (fs_user_mount_t *) current_mount->obj;
 
     // This is used to determine the writeability of the disk from USB.
     if (vfs->writeblocks[0] == MP_OBJ_NULL ||
@@ -170,9 +176,18 @@ Ctrl_status vfs_usb_write_10(uint32_t addr, volatile uint16_t nb_sector)
         }
         // Since by getting here we assume the mount is read-only to MicroPython
         // lets update the cached FatFs sector if its the one we just wrote.
-        fs_user_mount_t *vfs =  MP_STATE_PORT(fs_user_mount)[VFS_INDEX];
-        volatile uint16_t x = addr;
-        (void) x;
+        mp_vfs_mount_t* current_mount = MP_STATE_VM(vfs_mount_table);
+        for (uint8_t i = 0; current_mount != NULL; i++) {
+            if (i == VFS_INDEX) {
+                break;
+            }
+            current_mount = current_mount->next;
+        }
+        if (current_mount == NULL) {
+            return CTRL_NO_PRESENT;
+        }
+        fs_user_mount_t *vfs = (fs_user_mount_t *) current_mount->obj;
+
         #if _MAX_SS != _MIN_SS
         if (vfs->ssize == FILESYSTEM_BLOCK_SIZE) {
         #else
diff --git a/atmel-samd/builtin_open.c b/atmel-samd/builtin_open.c
deleted file mode 100644
index 697eec8ea..000000000
--- a/atmel-samd/builtin_open.c
+++ /dev/null
@@ -1,30 +0,0 @@
-/*
- * This file is part of the MicroPython project, http://micropython.org/
- *
- * The MIT License (MIT)
- *
- * Copyright (c) 2013, 2014 Damien P. George
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-#include "py/runtime.h"
-#include "extmod/vfs_fat_file.h"
-
-MP_DEFINE_CONST_FUN_OBJ_KW(mp_builtin_open_obj, 1, fatfs_builtin_open);
diff --git a/atmel-samd/common-hal/audioio/AudioOut.c b/atmel-samd/common-hal/audioio/AudioOut.c
index 9fb1a6ebe..cd840b4f8 100644
--- a/atmel-samd/common-hal/audioio/AudioOut.c
+++ b/atmel-samd/common-hal/audioio/AudioOut.c
@@ -27,6 +27,7 @@
 #include <stdint.h>
 #include <string.h>
 
+#include "extmod/vfs_fat_file.h"
 #include "py/gc.h"
 #include "py/mperrno.h"
 #include "py/runtime.h"
diff --git a/atmel-samd/fatfs_port.c b/atmel-samd/fatfs_port.c
index d47b9d6af..e1eba350a 100644
--- a/atmel-samd/fatfs_port.c
+++ b/atmel-samd/fatfs_port.c
@@ -26,19 +26,8 @@
 
 #include "py/mphal.h"
 #include "py/runtime.h"
-#include "lib/fatfs/ff.h"        /* FatFs lower layer API */
-#include "lib/fatfs/diskio.h"    /* FatFs lower layer API */
-
-const PARTITION VolToPart[MICROPY_FATFS_VOLUMES] = {
-    {0, 1},     // Logical drive 0 ==> Physical drive 0, 1st partition
-    {1, 0},     // Logical drive 1 ==> Physical drive 1 (auto detection)
-    {2, 0},     // Logical drive 2 ==> Physical drive 2 (auto detection)
-    {3, 0},     // Logical drive 3 ==> Physical drive 3 (auto detection)
-    /*
-    {0, 2},     // Logical drive 2 ==> Physical drive 0, 2nd partition
-    {0, 3},     // Logical drive 3 ==> Physical drive 0, 3rd partition
-    */
-};
+#include "lib/oofatfs/ff.h"        /* FatFs lower layer API */
+#include "lib/oofatfs/diskio.h"    /* FatFs lower layer API */
 
 DWORD get_fattime(void) {
     // TODO(tannewt): Support the RTC.
diff --git a/atmel-samd/flash_api.c b/atmel-samd/flash_api.c
index ab5de98fb..724d22e75 100644
--- a/atmel-samd/flash_api.c
+++ b/atmel-samd/flash_api.c
@@ -31,13 +31,17 @@
 #define VFS_INDEX 0
 
 void flash_set_usb_writeable(bool usb_writeable) {
-    if (VFS_INDEX >= MP_ARRAY_SIZE(MP_STATE_PORT(fs_user_mount))) {
-        return;
+    mp_vfs_mount_t* current_mount = MP_STATE_VM(vfs_mount_table);
+    for (uint8_t i = 0; current_mount != NULL; i++) {
+        if (i == VFS_INDEX) {
+            break;
+        }
+        current_mount = current_mount->next;
     }
-    fs_user_mount_t *vfs = MP_STATE_PORT(fs_user_mount)[VFS_INDEX];
-    if (vfs == NULL) {
+    if (current_mount == NULL) {
         return;
     }
+    fs_user_mount_t *vfs = (fs_user_mount_t *) current_mount->obj;
 
     if (usb_writeable) {
         vfs->flags |= FSUSER_USB_WRITEABLE;
diff --git a/atmel-samd/flash_api.h b/atmel-samd/flash_api.h
index e40f1932b..91bf7dc8b 100644
--- a/atmel-samd/flash_api.h
+++ b/atmel-samd/flash_api.h
@@ -26,7 +26,7 @@
 #ifndef __MICROPY_INCLUDED_ATMEL_SAMD_FLASH_API_H__
 #define __MICROPY_INCLUDED_ATMEL_SAMD_FLASH_API_H__
 
-#include "extmod/fsusermount.h"
+#include "extmod/vfs_fat.h"
 
 extern void flash_init_vfs(fs_user_mount_t *vfs);
 extern void flash_flush(void);
diff --git a/atmel-samd/internal_flash.c b/atmel-samd/internal_flash.c
index 98dc92608..bd5963e11 100644
--- a/atmel-samd/internal_flash.c
+++ b/atmel-samd/internal_flash.c
@@ -28,11 +28,12 @@
 #include <stdint.h>
 #include <string.h>
 
+#include "extmod/vfs.h"
+#include "extmod/vfs_fat.h"
 #include "py/mphal.h"
 #include "py/obj.h"
 #include "py/runtime.h"
-#include "lib/fatfs/ff.h"
-#include "extmod/fsusermount.h"
+#include "lib/oofatfs/ff.h"
 
 #include "asf/sam0/drivers/nvm/nvm.h"
 #include "asf/sam0/drivers/port/port.h"
diff --git a/atmel-samd/main.c b/atmel-samd/main.c
index 563237a3c..1f3c3405c 100644
--- a/atmel-samd/main.c
+++ b/atmel-samd/main.c
@@ -9,11 +9,11 @@
 #include "py/gc.h"
 #include "py/stackctrl.h"
 
-#include "lib/fatfs/ff.h"
-#include "lib/fatfs/diskio.h"
+#include "extmod/vfs_fat.h"
+#include "lib/oofatfs/ff.h"
+#include "lib/oofatfs/diskio.h"
 #include "lib/mp-readline/readline.h"
 #include "lib/utils/pyexec.h"
-#include "extmod/fsusermount.h"
 
 #include "asf/common/services/sleepmgr/sleepmgr.h"
 #include "asf/common/services/usb/udc/udc.h"
@@ -48,6 +48,7 @@
 #include "tick.h"
 
 fs_user_mount_t fs_user_mount_flash;
+mp_vfs_mount_t mp_vfs_mount_flash;
 
 typedef enum {
     NO_SAFE_MODE = 0,
@@ -80,39 +81,42 @@ void do_str(const char *src, mp_parse_input_kind_t input_kind) {
 // want it to be executed without using stack within main() function
 void init_flash_fs(void) {
     // init the vfs object
-    fs_user_mount_t *vfs = &fs_user_mount_flash;
-    vfs->str = "/flash";
-    vfs->len = 6;
-    vfs->flags = 0;
-    flash_init_vfs(vfs);
-
-    // put the flash device in slot 0 (it will be unused at this point)
-    MP_STATE_PORT(fs_user_mount)[0] = vfs;
+    fs_user_mount_t *vfs_fat = &fs_user_mount_flash;
+    vfs_fat->flags = 0;
+    flash_init_vfs(vfs_fat);
 
     // try to mount the flash
-    FRESULT res = f_mount(&vfs->fatfs, vfs->str, 1);
+    FRESULT res = f_mount(&vfs_fat->fatfs);
 
     if (res == FR_NO_FILESYSTEM) {
         // no filesystem so create a fresh one
 
-        res = f_mkfs("/flash", 0, 0);
+        uint8_t working_buf[_MAX_SS];
+        res = f_mkfs(&vfs_fat->fatfs, FM_FAT, 0, working_buf, sizeof(working_buf));
         // Flush the new file system to make sure its repaired immediately.
         flash_flush();
         if (res != FR_OK) {
-            MP_STATE_PORT(fs_user_mount)[0] = NULL;
             return;
         }
 
         // set label
-        f_setlabel("CIRCUITPY");
+        f_setlabel(&vfs_fat->fatfs, "CIRCUITPY");
     } else if (res != FR_OK) {
-        MP_STATE_PORT(fs_user_mount)[0] = NULL;
         return;
     }
+    mp_vfs_mount_t *vfs = m_new_obj_maybe(mp_vfs_mount_t);
+    if (vfs == NULL) {
+        return;
+    }
+    vfs->str = "/";
+    vfs->len = 1;
+    vfs->obj = MP_OBJ_FROM_PTR(vfs_fat);
+    vfs->next = NULL;
+    MP_STATE_VM(vfs_mount_table) = vfs;
 
     // The current directory is used as the boot up directory.
     // It is set to the internal flash filesystem by default.
-    f_chdrive("/flash");
+    MP_STATE_PORT(vfs_cur) = vfs;
 }
 
 static char heap[16384];
@@ -124,9 +128,7 @@ void reset_mp(void) {
 
     // Sync the file systems in case any used RAM from the GC to cache. As soon
     // as we re-init the GC all bets are off on the cache.
-    disk_ioctl(0, CTRL_SYNC, NULL);
-    disk_ioctl(1, CTRL_SYNC, NULL);
-    disk_ioctl(2, CTRL_SYNC, NULL);
+    flash_flush();
 
     // Clear the readline history. It references the heap we're about to destroy.
     readline_init0();
@@ -230,13 +232,8 @@ void reset_samd21(void) {
 }
 
 bool maybe_run(const char* filename, pyexec_result_t* exec_result) {
-    FILINFO fno;
-#if _USE_LFN
-    fno.lfname = NULL;
-    fno.lfsize = 0;
-#endif
-    FRESULT res = f_stat(filename, &fno);
-    if (res != FR_OK || fno.fattrib & AM_DIR) {
+    mp_import_stat_t stat = mp_import_stat(filename);
+    if (stat != MP_IMPORT_STAT_FILE) {
         return false;
     }
     mp_hal_stdout_tx_str(filename);
@@ -607,7 +604,8 @@ int main(void) {
         #ifdef CIRCUITPY_BOOT_OUTPUT_FILE
         FIL file_pointer;
         boot_output_file = &file_pointer;
-        f_open(boot_output_file, CIRCUITPY_BOOT_OUTPUT_FILE, FA_WRITE | FA_CREATE_ALWAYS);
+        f_open(&((fs_user_mount_t *) MP_STATE_VM(vfs_mount_table)->obj)->fatfs,
+            boot_output_file, CIRCUITPY_BOOT_OUTPUT_FILE, FA_WRITE | FA_CREATE_ALWAYS);
         #endif
 
         // TODO(tannewt): Re-add support for flashing boot error output.
@@ -688,17 +686,8 @@ void gc_collect(void) {
     gc_collect_end();
 }
 
-mp_import_stat_t fat_vfs_import_stat(const char *path);
-mp_import_stat_t mp_import_stat(const char *path) {
-    #if MICROPY_VFS_FAT
-    return fat_vfs_import_stat(path);
-    #else
-    (void)path;
-    return MP_IMPORT_STAT_NO_EXIST;
-    #endif
-}
-
-void nlr_jump_fail(void *val) {
+void NORETURN nlr_jump_fail(void *val) {
+    while (1);
 }
 
 void NORETURN __fatal_error(const char *msg) {
diff --git a/atmel-samd/moduos.c b/atmel-samd/moduos.c
index f30d85ecd..cdc6325f2 100644
--- a/atmel-samd/moduos.c
+++ b/atmel-samd/moduos.c
@@ -32,11 +32,11 @@
 #include "py/objstr.h"
 #include "py/runtime.h"
 #include "genhdr/mpversion.h"
-#include "lib/fatfs/ff.h"
-#include "lib/fatfs/diskio.h"
+#include "lib/oofatfs/ff.h"
+#include "lib/oofatfs/diskio.h"
+#include "extmod/vfs.h"
+#include "extmod/vfs_fat.h"
 #include "timeutils.h"
-#include "extmod/vfs_fat_file.h"
-#include "extmod/fsusermount.h"
 
 /// \module os - basic "operating system" services
 ///
@@ -76,285 +76,42 @@ STATIC mp_obj_t os_uname(void) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_0(os_uname_obj, os_uname);
 
-/// \function chdir(path)
-/// Change current directory.
-STATIC mp_obj_t os_chdir(mp_obj_t path_in) {
-    const char *path;
-    path = mp_obj_str_get_str(path_in);
-
-    FRESULT res = f_chdrive(path);
-
-    if (res == FR_OK) {
-        res = f_chdir(path);
-    }
-
-    if (res != FR_OK) {
-        // TODO should be mp_type_FileNotFoundError
-        nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError, "No such file or directory: '%s'", path));
-    }
-
-    return mp_const_none;
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_1(os_chdir_obj, os_chdir);
-
-/// \function getcwd()
-/// Get the current directory.
-STATIC mp_obj_t os_getcwd(void) {
-    char buf[MICROPY_ALLOC_PATH_MAX + 1];
-    FRESULT res = f_getcwd(buf, sizeof buf);
-
-    if (res != FR_OK) {
-        mp_raise_OSError(fresult_to_errno_table[res]);
-    }
-
-    return mp_obj_new_str(buf, strlen(buf), false);
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_0(os_getcwd_obj, os_getcwd);
-
-/// \function listdir([dir])
-/// With no argument, list the current directory.  Otherwise list the given directory.
-STATIC mp_obj_t os_listdir(mp_uint_t n_args, const mp_obj_t *args) {
-    bool is_str_type = true;
-    const char *path;
-    if (n_args == 1) {
-        if (mp_obj_get_type(args[0]) == &mp_type_bytes) {
-            is_str_type = false;
-        }
-        path = mp_obj_str_get_str(args[0]);
-    } else {
-        path = "";
-    }
-
-    // "hack" to list root directory
-    if (path[0] == '/' && path[1] == '\0') {
-        mp_obj_t dir_list = mp_obj_new_list(0, NULL);
-        for (size_t i = 0; i < MP_ARRAY_SIZE(MP_STATE_PORT(fs_user_mount)); ++i) {
-            fs_user_mount_t *vfs = MP_STATE_PORT(fs_user_mount)[i];
-            if (vfs != NULL) {
-                mp_obj_list_append(dir_list, mp_obj_new_str(vfs->str + 1, vfs->len - 1, false));
-            }
-        }
-        return dir_list;
-    }
-
-    return fat_vfs_listdir(path, is_str_type);
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(os_listdir_obj, 0, 1, os_listdir);
-
-/// \function mkdir(path)
-/// Create a new directory.
-STATIC mp_obj_t os_mkdir(mp_obj_t path_o) {
-    const char *path = mp_obj_str_get_str(path_o);
-    FRESULT res = f_mkdir(path);
-    switch (res) {
-        case FR_OK:
-            return mp_const_none;
-        case FR_EXIST:
-            // TODO should be FileExistsError
-            nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError, "File exists: '%s'", path));
-        default:
-            nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError, "Error creating directory '%s'", path));
-    }
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_1(os_mkdir_obj, os_mkdir);
-
-/// \function remove(path)
-/// Remove a file.
-STATIC mp_obj_t os_remove(mp_obj_t path_o) {
-    const char *path = mp_obj_str_get_str(path_o);
-    // TODO check that path is actually a file before trying to unlink it
-    FRESULT res = f_unlink(path);
-    switch (res) {
-        case FR_OK:
-            return mp_const_none;
-        default:
-            nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError, "Error removing file '%s'", path));
-    }
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_1(os_remove_obj, os_remove);
-
-/// \function rename(old_path, new_path)
-/// Rename a file
-STATIC mp_obj_t os_rename(mp_obj_t path_in, mp_obj_t path_out) {
-    const char *old_path = mp_obj_str_get_str(path_in);
-    const char *new_path = mp_obj_str_get_str(path_out);
-    FRESULT res = f_rename(old_path, new_path);
-    switch (res) {
-        case FR_OK:
-            return mp_const_none;
-        default:
-            nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError, "Error renaming file '%s' to '%s'", old_path, new_path));
-    }
-
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_2(os_rename_obj, os_rename);
-
-/// \function rmdir(path)
-/// Remove a directory.
-STATIC mp_obj_t os_rmdir(mp_obj_t path_o) {
-    const char *path = mp_obj_str_get_str(path_o);
-    // TODO check that path is actually a directory before trying to unlink it
-    FRESULT res = f_unlink(path);
-    switch (res) {
-        case FR_OK:
-            return mp_const_none;
-        default:
-            nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_OSError, "Error removing directory '%s'", path));
-    }
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_1(os_rmdir_obj, os_rmdir);
-
-// Checks for path equality, ignoring trailing slashes:
-//   path_equal(/, /) -> true
-//   path_equal(/flash//, /flash) -> true
-// second argument must be in canonical form (meaning no trailing slash, unless it's just /)
-STATIC bool path_equal(const char *path, const char *path_canonical) {
-    for (; *path_canonical != '\0' && *path == *path_canonical; ++path, ++path_canonical) {
-    }
-    if (*path_canonical != '\0') {
-        return false;
-    }
-    for (; *path == '/'; ++path) {
-    }
-    return *path == '\0';
-}
-
-/// \function stat(path)
-/// Get the status of a file or directory.
-STATIC mp_obj_t os_stat(mp_obj_t path_in) {
-    const char *path = mp_obj_str_get_str(path_in);
-
-    FILINFO fno;
-#if _USE_LFN
-    fno.lfname = NULL;
-    fno.lfsize = 0;
-#endif
-
-    FRESULT res;
-    if (path_equal(path, "/")) {
-        // stat root directory
-	fno.fsize = 0;
-	fno.fdate = 0;
-	fno.ftime = 0;
-	fno.fattrib = AM_DIR;
-    } else {
-        res = FR_NO_PATH;
-        for (size_t i = 0; i < MP_ARRAY_SIZE(MP_STATE_PORT(fs_user_mount)); ++i) {
-            fs_user_mount_t *vfs = MP_STATE_PORT(fs_user_mount)[i];
-            if (vfs != NULL && path_equal(path, vfs->str)) {
-                // stat mounted device directory
-                fno.fsize = 0;
-                fno.fdate = 0;
-                fno.ftime = 0;
-                fno.fattrib = AM_DIR;
-                res = FR_OK;
-            }
-        }
-        if (res == FR_NO_PATH) {
-            // stat normal file
-            res = f_stat(path, &fno);
-        }
-        if (res != FR_OK) {
-            nlr_raise(mp_obj_new_exception_arg1(&mp_type_OSError,
-                MP_OBJ_NEW_SMALL_INT(fresult_to_errno_table[res])));
-        }
-    }
-
-    mp_obj_tuple_t *t = mp_obj_new_tuple(10, NULL);
-    mp_int_t mode = 0;
-    if (fno.fattrib & AM_DIR) {
-        mode |= 0x4000; // stat.S_IFDIR
-    } else {
-        mode |= 0x8000; // stat.S_IFREG
-    }
-    mp_int_t seconds = timeutils_seconds_since_2000(
-        1980 + ((fno.fdate >> 9) & 0x7f),
-        (fno.fdate >> 5) & 0x0f,
-        fno.fdate & 0x1f,
-        (fno.ftime >> 11) & 0x1f,
-        (fno.ftime >> 5) & 0x3f,
-        2 * (fno.ftime & 0x1f)
-    );
-    t->items[0] = MP_OBJ_NEW_SMALL_INT(mode); // st_mode
-    t->items[1] = MP_OBJ_NEW_SMALL_INT(0); // st_ino
-    t->items[2] = MP_OBJ_NEW_SMALL_INT(0); // st_dev
-    t->items[3] = MP_OBJ_NEW_SMALL_INT(0); // st_nlink
-    t->items[4] = MP_OBJ_NEW_SMALL_INT(0); // st_uid
-    t->items[5] = MP_OBJ_NEW_SMALL_INT(0); // st_gid
-    t->items[6] = MP_OBJ_NEW_SMALL_INT(fno.fsize); // st_size
-    t->items[7] = MP_OBJ_NEW_SMALL_INT(seconds); // st_atime
-    t->items[8] = MP_OBJ_NEW_SMALL_INT(seconds); // st_mtime
-    t->items[9] = MP_OBJ_NEW_SMALL_INT(seconds); // st_ctime
-
-    return t;
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_1(os_stat_obj, os_stat);
-
-STATIC mp_obj_t os_statvfs(mp_obj_t path_in) {
-    const char *path = mp_obj_str_get_str(path_in);
-
-    DWORD nclst;
-    FATFS *fatfs;
-    FRESULT res = f_getfree(path, &nclst, &fatfs);
-    if (res != FR_OK) {
-        goto error;
-    }
-
-    mp_obj_tuple_t *t = mp_obj_new_tuple(10, NULL);
-
-    t->items[0] = MP_OBJ_NEW_SMALL_INT(fatfs->csize * 512); // f_bsize - block size
-    t->items[1] = t->items[0];                  // f_frsize - fragment size
-    t->items[2] = MP_OBJ_NEW_SMALL_INT(0);      // f_blocks - total number of blocks
-    t->items[3] = MP_OBJ_NEW_SMALL_INT(nclst);  // f_bfree  - number of free blocks
-    t->items[4] = t->items[3];                  // f_bavail - free blocks avail to unpriviledged users
-    t->items[5] = MP_OBJ_NEW_SMALL_INT(0);      // f_files - # inodes
-    t->items[6] = MP_OBJ_NEW_SMALL_INT(0);      // f_ffree - # free inodes
-    t->items[7] = MP_OBJ_NEW_SMALL_INT(0);      // f_favail - # free inodes avail to unpriviledges users
-    t->items[8] = MP_OBJ_NEW_SMALL_INT(0);      // f_flags
-    t->items[9] = MP_OBJ_NEW_SMALL_INT(_MAX_LFN);   // f_namemax
-
-    return t;
-
-error:
-    nlr_raise(mp_obj_new_exception_arg1(&mp_type_OSError, MP_OBJ_NEW_SMALL_INT(fresult_to_errno_table[res])));
-}
-STATIC MP_DEFINE_CONST_FUN_OBJ_1(os_statvfs_obj, os_statvfs);
-
 /// \function sync()
 /// Sync all filesystems.
 STATIC mp_obj_t os_sync(void) {
-    disk_ioctl(0, CTRL_SYNC, NULL);
-    disk_ioctl(1, CTRL_SYNC, NULL);
-    disk_ioctl(2, CTRL_SYNC, NULL);
+    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);
+    }
     return mp_const_none;
 }
 MP_DEFINE_CONST_FUN_OBJ_0(mod_os_sync_obj, os_sync);
 
-STATIC const mp_map_elem_t os_module_globals_table[] = {
+STATIC const mp_rom_map_elem_t os_module_globals_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR___name__), MP_OBJ_NEW_QSTR(MP_QSTR_uos) },
 
-    { MP_OBJ_NEW_QSTR(MP_QSTR_uname), (mp_obj_t)&os_uname_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_uname), MP_ROM_PTR(&os_uname_obj) },
 
-    { MP_OBJ_NEW_QSTR(MP_QSTR_chdir), (mp_obj_t)&os_chdir_obj },
-    { MP_OBJ_NEW_QSTR(MP_QSTR_getcwd), (mp_obj_t)&os_getcwd_obj },
-    { MP_OBJ_NEW_QSTR(MP_QSTR_listdir), (mp_obj_t)&os_listdir_obj },
-    { MP_OBJ_NEW_QSTR(MP_QSTR_mkdir), (mp_obj_t)&os_mkdir_obj },
-    { MP_OBJ_NEW_QSTR(MP_QSTR_remove), (mp_obj_t)&os_remove_obj },
-    { MP_OBJ_NEW_QSTR(MP_QSTR_rename),(mp_obj_t)&os_rename_obj},
-    { MP_OBJ_NEW_QSTR(MP_QSTR_rmdir), (mp_obj_t)&os_rmdir_obj },
-    { MP_OBJ_NEW_QSTR(MP_QSTR_stat), (mp_obj_t)&os_stat_obj },
-    { MP_OBJ_NEW_QSTR(MP_QSTR_statvfs), (mp_obj_t)&os_statvfs_obj },
-    { MP_OBJ_NEW_QSTR(MP_QSTR_unlink), (mp_obj_t)&os_remove_obj }, // unlink aliases to remove
+    { MP_OBJ_NEW_QSTR(MP_QSTR_chdir), MP_ROM_PTR(&mp_vfs_chdir_obj) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_getcwd), MP_ROM_PTR(&mp_vfs_getcwd_obj) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_listdir), MP_ROM_PTR(&mp_vfs_listdir_obj) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_mkdir), MP_ROM_PTR(&mp_vfs_mkdir_obj) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_remove), MP_ROM_PTR(&mp_vfs_remove_obj) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_rename), MP_ROM_PTR(&mp_vfs_rename_obj) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_rmdir), MP_ROM_PTR(&mp_vfs_rmdir_obj) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_stat), MP_ROM_PTR(&mp_vfs_stat_obj) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_statvfs), MP_ROM_PTR(&mp_vfs_statvfs_obj) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_unlink), MP_ROM_PTR(&mp_vfs_remove_obj) }, // unlink aliases to remove
 
-    { MP_OBJ_NEW_QSTR(MP_QSTR_sync), (mp_obj_t)&mod_os_sync_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_sync), MP_ROM_PTR(&mod_os_sync_obj) },
 
     /// \constant sep - separation character used in paths
     { MP_OBJ_NEW_QSTR(MP_QSTR_sep), MP_OBJ_NEW_QSTR(MP_QSTR__slash_) },
 
     // these are MicroPython extensions
-    { MP_OBJ_NEW_QSTR(MP_QSTR_mount), (mp_obj_t)&fsuser_mount_obj },
-    { MP_OBJ_NEW_QSTR(MP_QSTR_umount), (mp_obj_t)&fsuser_umount_obj },
-    { MP_OBJ_NEW_QSTR(MP_QSTR_mkfs), (mp_obj_t)&fsuser_mkfs_obj },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_mount), MP_ROM_PTR(&mp_vfs_mount_obj) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_umount), MP_ROM_PTR(&mp_vfs_umount_obj) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_VfsFat), MP_ROM_PTR(&mp_fat_vfs_type) },
 };
 
 STATIC MP_DEFINE_CONST_DICT(os_module_globals, os_module_globals_table);
diff --git a/atmel-samd/mpconfigport.h b/atmel-samd/mpconfigport.h
index 926bff72b..b6175edb9 100644
--- a/atmel-samd/mpconfigport.h
+++ b/atmel-samd/mpconfigport.h
@@ -38,6 +38,10 @@
 #define MICROPY_PY_BUILTINS_BYTEARRAY (1)
 #define MICROPY_PY_BUILTINS_MEMORYVIEW (1)
 #define MICROPY_PY_BUILTINS_ENUMERATE (1)
+#define MICROPY_PY_BUILTINS_HELP    (1)
+#define MICROPY_PY_BUILTINS_HELP_MODULES (1)
+#define MICROPY_PY_BUILTINS_HELP_TEXT circuitpython_help_text
+#define MICROPY_PY_BUILTINS_INPUT   (1)
 #define MICROPY_PY_BUILTINS_FILTER  (1)
 #define MICROPY_PY_BUILTINS_SET     (1)
 #define MICROPY_PY_BUILTINS_SLICE   (1)
@@ -69,13 +73,13 @@
 #define MICROPY_FATFS_VOLUMES          (4)
 #define MICROPY_FATFS_MULTI_PARTITION  (1)
 #define MICROPY_FATFS_NUM_PERSISTENT   (1)
-#define MICROPY_FSUSERMOUNT            (1)
 // Only enable this if you really need it. It allocates a byte cache of this
 // size.
 // #define MICROPY_FATFS_MAX_SS           (4096)
 
 #define FILESYSTEM_BLOCK_SIZE       (512)
 
+#define MICROPY_VFS                 (1)
 #define MICROPY_VFS_FAT             (1)
 #define MICROPY_PY_MACHINE          (1)
 #define MICROPY_MODULE_WEAK_LINKS   (0)
@@ -85,7 +89,7 @@
 #define MICROPY_USE_INTERNAL_PRINTF (1)
 #define MICROPY_PY_SYS_STDFILES     (1)
 #define MICROPY_PY_IO_FILEIO        (1)
-#define MICROPY_READER_FATFS        (1)
+#define MICROPY_READER_VFS        (1)
 #define MICROPY_PERSISTENT_CODE_LOAD (1)
 #define MICROPY_PY_BUILTINS_STR_UNICODE (1)
 
@@ -112,6 +116,9 @@ typedef long mp_off_t;
 
 #define MP_PLAT_PRINT_STRN(str, len) mp_hal_stdout_tx_strn_cooked(str, len)
 
+#define mp_import_stat mp_vfs_import_stat
+#define mp_builtin_open_obj mp_vfs_open_obj
+
 // extra built in names to add to the global namespace
 #define MICROPY_PORT_BUILTINS \
     { MP_OBJ_NEW_QSTR(MP_QSTR_help), (mp_obj_t)&mp_builtin_help_obj }, \
diff --git a/atmel-samd/mphalport.h b/atmel-samd/mphalport.h
index 6c9392105..4848e1404 100644
--- a/atmel-samd/mphalport.h
+++ b/atmel-samd/mphalport.h
@@ -29,7 +29,7 @@
 
 #include "py/obj.h"
 
-#include "lib/fatfs/ff.h"
+#include "lib/oofatfs/ff.h"
 
 #define USB_RX_BUF_SIZE 128
 
diff --git a/atmel-samd/spi_flash.c b/atmel-samd/spi_flash.c
index a534d2dd9..7f3c8984c 100644
--- a/atmel-samd/spi_flash.c
+++ b/atmel-samd/spi_flash.c
@@ -30,11 +30,12 @@
 
 #include "asf/sam0/drivers/sercom/spi/spi.h"
 
+#include "extmod/vfs.h"
+#include "extmod/vfs_fat.h"
 #include "py/gc.h"
 #include "py/obj.h"
 #include "py/runtime.h"
-#include "lib/fatfs/ff.h"
-#include "extmod/fsusermount.h"
+#include "lib/oofatfs/ff.h"
 
 #include "rgb_led_status.h"
 #include "shared_dma.h"