From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from majordomo by infradead.org with local (Exim 3.16 #2) id 13Zap0-0001yH-00 for mtd-list@infradead.org; Thu, 14 Sep 2000 16:21:06 +0100 Received: from runyon.cygnus.com ([205.180.230.5] helo=cygnus.com) by infradead.org with esmtp (Exim 3.16 #2) id 13Zaoy-0001yB-00 for mtd@infradead.org; Thu, 14 Sep 2000 16:21:04 +0100 From: David Woodhouse In-Reply-To: References: To: "David Given" Cc: mtd@infradead.org Subject: Re: CFI detection of x16 chips in x8 mode Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Thu, 14 Sep 2000 16:20:47 +0100 Message-ID: <22135.968944847@passion.cygnus.co.uk> Sender: owner-mtd@infradead.org List-ID: dg@tao-group.com said: > How does jffs work? Erasing a single sector seems to take quite a > while on this device. How does jffs manage to be so fast? You don't have to make the user wait while you erase a sector. You can do it from a kernel thread in the background, and make sure you've always got some space available You can also interrupt erases on some flash chips, and read from the filesystem even while you're waiting from an erase. We don't do that yet, but it's close. > I believe it ought to be possible to persuade FlashFX to share a > device with jffs. The way you'd do this is to use FXFMT to create a > VBF volume that only uses, say, half the device. You'd then have to > modify the partition table in sbc_mediagx.c to reflect this; you'd > have three partitions: the boot partition (256kB); the VBF volume > (8MB); and everything else (8MB). jffs would live in /dev/mtd/3. This > ought to let you boot DOS on the VBF volume and then use LILO or > loadlin to start Linux. Theoretically possible. Probably better to get it to boot off the JFFS directly though, if you can. It'd be nice if someone with the source to the flashfx stuff could release a version which works on MTD devices. > However, there has *got* to be some better way of handling > partitions... the Arcom board seems to have a 256kB block at the > beginning of the flash for ROM extensions, so it would make sense to > have that as one partition. For the rest, it would seem logical that > since FlashFX can find the VBF volume, so could we, and so we should > be able to autodetect it. But does anyone know how? Not easy to do this in a generic manner, and deal with all possible schemes for splitting the devices up. -- dwmw2 To unsubscribe, send "unsubscribe mtd" to majordomo@infradead.org