Linux block driver for the DexDrive

The DexDrive is a device that connects via the serial port, and allows access to PlayStation or Nintendo 64 memory cards (depending on the model). This Linux driver provides block device functionality for the DexDrive, making it possible to format/mount a memory card like any other block device.

This driver was written mostly as a personal challenge, and not out of any need or usefulness. After all, a regular PlayStation memory card holds a mere 128 KiB of data, and a Nintendo 64 Controller Pak holds a whopping 32 KiB. While these figures weren't too laughable ten years ago, nowadays you can get much larger (and faster) USB sticks for free with your breakfast cereal.

(But hey, if something can be done, why bother with such mundane details as whether or not it would make any sense?)

Please note that if you're merely looking for a way to read/write memory cards, this driver is overkill. Instead, you may want to look at Dexux, an application/library that does just that.

COMPILATION

Compiling this module requires a fully configured kernel source tree. By default, simply running make will compile against the source tree of the currently running kernel. If this is not appropriate, you can specify the location of your kernel source tree:

$ make KERNELDIR=/usr/src/linux

This will compile the dexdrive.ko kernel module, as well as the dexattach utility. You can install them both with make install, with an optional DESTDIR argument if you don't want to install them as root.

USAGE

After loading the dexdrive module (with insmod or modprobe) and connecting a DexDrive to a serial port, the block device is created by running dexattach on that serial port:

$ dexattach --check --verbose /dev/ttyS0
Opening /dev/ttyS0 and setting line discipline
Device number is 254:0

(If you get a Cannot set line discipline: Invalid argument error, it is most likely that the dexdrive module isn't loaded.)

If you are running udev, a block device entry will be automatically created as /dev/dexdrive0. If you are not running udev, you will need to create that entry yourself, as root:

# mknod --mode=0660 /dev/dexdrive0 b 254 0
# chgrp floppy /dev/dexdrive0

At this point, you can use /dev/dexdrive0 like you would any other (tiny) block device. That device will remain active for as long as dexattach is running.

Up to four block devices can be active at the same time.

OTHER FEATURES

Two sysfs entries are created to provide the DexDrive model (PSX or N64) and firmware revision:

$ cat /sys/block/dexdrive0/model
PSX
$ cat /sys/block/dexdrive0/firmware_version
1.12

COMPATIBILITY

This module is compatible with kernel versions 3.0 and up.

It supports both the PlayStation and Nintendo 64 DexDrive models, using any compatible memory card. No explicit support is provided for non-conventional memory cards with larger capacity, but they will still work in that they behave like a regular memory card. (Page switching will have to be handled manually, though.)

SOURCE

The complete source for this driver can be found on GitHub:

https://github.com/fbriere/linux-dexdrive

CONTACT

Author: Frédéric Brière - fbriere@fbriere.net

Please feel free to email me if you have any questions, bugs, patches, or general comments on my sanity for writing this driver. :smile: