STM32 VFS

Simple VFS for SMT32 MCU and FS for spi flash devices. FS using only static allocation and requires minimum 8kB of RAM for it's operation. Because of only 1-level indirection maximum allowed file size is limited with approximately 16Mb. Every block has a CRC protection.

Structure

• main.c — a simple terminal program to demonstrate and test vfs functions.
• uartterm.c and uartterm.h — API and functions that implement unix-like ternimal working through UART.
• driver.h — common interface for drivers in this project.
• filesystem.c and filesystem.h — common interface for filesystems in this project.
• w25.c and w25.h — driver that implement most basic function of W25Q SPI flash memory.
• sfs.c and sfs.h — A simple filesystem.
• rfs.c and rfs.h — Filesystem that resides in RAM.
• call.c and call.h — Implementation for system call not related to VFS.

UART terminal

UART terminal is used for testing and resembeles typical UNIX shell.

Driver commands

• sd [dev] -- set current device to [dev]
• rd [addr] -- read data at address [addr]
• wd [addr] [str] -- write string [str] into [addr]

Filesystem commands

• f -- format choosen device
• i [struct] {[addr]} -- dump filesystem [struct] (sb, in, bm) at [addr]
• c [sz] -- create inode for data size of [size]
• d [addr] -- delete inode with address [addr]
• s [addr] [data] -- set data for inode with address [addr] to [data]
• g [addr] -- get data from inode with address [addr]
• r [addr] [off] [sz] -- read [sz] bytes from inode with address [addr] with offset of [off] bytes
• w [addr] [off] [data] -- write data into inode with address [addr] with offset of [off] bytes

Virtual filesystem commands

• mount [dev] [target] -- mount [dev] to [target]
• format [target] -- format device mounted at [target]
• umount [dev] [target] -- unmount [target]
• mountlist -- get list of mounted devices
• open [path] [flags] -- open file with [path], if [flags] is 'c', create it
• read [fd] [sz] -- read [sz] bytes from opened file with descriptor [fd]
• write [fd] [data] -- write [data] into opened file with descriptor [fd]
• close [fd] -- close opened file with descriptor [fd]
• mkdir [path] -- create directory [path]
• rm [path] -- delete file or directory [path]
• ls [path] -- get list of file in directory [path]
• cd [path] -- change current working directory to [path]

What's done

• Filesystem mounting/unmounting.
• open/close and read/write calls in VFS.
• Simple filesystem, bad version of ext with built-in checksums.
• Naive implementations of malloc/free/realloc.
• RAM filesystem and that malloc/free/realloc calls.
• Common interfaces for filesystems and drivers.

What's not done

• Device files
• Page cache
• Unit tests