Subject: Re: mods for proposed port 'tsarm' (now committed)
To: Toru Nishimura <>
From: Jesse Off <>
List: port-arm
Date: 12/26/2004 21:07:26
Linux has a driver subsystem dubbed "mtd" (memory technology devices) and
a slew of filesystems that work with the various types of
etc..)   You can't treat flash chips like a regular block device and need
to do clever things like wear-leveling, bad-block management, and ECC in
software.  What the industry seems to be gravitating toward is 2KB-block
NAND flash chips.  Future lines of PC/104 ARM SBC's from Technologic
Systems won't even have a compact flash socket and will instead have
256MB+ of flash soldered right on the board.

With a few mods, LFS would be a great filesystem for raw flash devices,
but I think what might be the better way to go would be to emulate in
software what the controller chips do on the more well known flash devices
like CompactFlash, USB thumb drives, etc..  I hear its hard to come up
with something original in this area that doesn't infringe on existing
patents though...

P.S. I just commited support for the TS-7200 realtime clock and watchdog

//Jesse Off

> Jesse Off said;
>> Okay.  I've just committed this as a sub-port to evbarm called "tsarm".
>> On-board and on-chip peripherals are mostly supported.  There is work
>> still to be done:
>>  *) block disk driver for onboard strataflash (?)
> I have been considering to make NOR/NAND device driver to offer any
> kind of filesys for long time.   Some embed Linux products in market have
> field upgrade facility.   The most sophisticated one I've ever seen
> provides
> special FTP/TFTP demon inside which can write received new operating
> code into mmaped NOR storage and resets the hardware when completed.
> Toru Nishimura/ALKYL Technology