The Visual Memory Unit (VMU) for a Sega Dreamcast includes a small slab
of flash memory which is formatted with a file allocation table (FAT)
based file system. This patch adds support for that file system in a
hardware independent way (ie you can build and mount a VMUFAT filesystem
on other systems than a Dreamcast).

The code supports the Dreamcast factory settings and other volume sizes.

It is neither mtd nor Dreamcast/SH dependent.

The patch set includes new documentation, modifications to Kconfig, the filesystem code (in inode.c and super.c and the vmufat.h) and adds a new 'magic number' based on the VMUFAT format.

The code has been tested on a Dreamcast (and built with a 32 bit
compiler) and on x86_64.

Tools to format a filesystem are available here: https://github.com/mcmenaminadrian/mkfs.vmufat

(Resending after typo in previous subject line)

Signed-off-by: Adrian McMenamin <adrianmcmenamin@gmail.com>

---
 Documentation/filesystems/index.rst  |    1 +
 Documentation/filesystems/vmufat.rst |  127 ++++
 fs/Kconfig                           |    1 +
 fs/Makefile                          |    1 +
 fs/vmufat/Kconfig                    |   14 +
 fs/vmufat/Makefile                   |    7 +
 fs/vmufat/inode.c                    | 1017 ++++++++++++++++++++++++++
 fs/vmufat/super.c                    |  581 +++++++++++++++
 fs/vmufat/vmufat.h                   |  126 ++++
 include/uapi/linux/magic.h           |    1 +
 10 files changed, 1876 insertions(+)
 create mode 100644 Documentation/filesystems/vmufat.rst
 create mode 100644 fs/vmufat/Kconfig
 create mode 100644 fs/vmufat/Makefile
 create mode 100644 fs/vmufat/inode.c
 create mode 100644 fs/vmufat/super.c
 create mode 100644 fs/vmufat/vmufat.h