From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.nokia.com ([192.100.105.134] helo=mgw-mx09.nokia.com) by bombadil.infradead.org with esmtps (Exim 4.68 #1 (Red Hat Linux)) id 1Jyi6P-0001N3-Vp for linux-mtd@lists.infradead.org; Wed, 21 May 2008 06:47:10 +0000 Subject: Re: Support of removable MTD devices and other advanced features (follow-up from lkml) From: Artem Bityutskiy To: Alex Dubov In-Reply-To: <411628.55054.qm@web36703.mail.mud.yahoo.com> References: <411628.55054.qm@web36703.mail.mud.yahoo.com> Content-Type: text/plain; charset=utf-8 Date: Wed, 21 May 2008 09:47:12 +0300 Message-Id: <1211352433.31023.19.camel@sauron> Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Cc: linux-mtd@lists.infradead.org Reply-To: dedekind@infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi, I do not know much about SmartMedia and so on, so I cannot really comment. I mail more because I am afraid your mail will not be answered. Probably you should keep CCing LKML, not sure. On Tue, 2008-05-20 at 06:59 -0700, Alex Dubov wrote: > And third, architectural switch I'm proposing should not require modifica= tion > to low level chip drivers or higher level functionality of UBI kind. They= can > be glued together with relative ease (callback architecture is quite flex= ible). > My target is device management and FTL drivers. >=20 > Therefore, I propose (and intend to implement) a new architecture for MTD= core, > modeled after the block device API. The "alpha" version of it is here: >=20 > http://gentoo-wiki.com/User:Oakad/mtd_proposal I've briefly read through this. I think it is nice having an asynchronous interface based on requests. Probably UBI/UBIFS would benefit from it as well. Just few thoughts: 1. You will probably need to solve the horrible MTD problem - it does not support devices larger than 4GiB because it uses absolute 32-bit offsets. 2. You will need to make MTD sysfs-aware. 3. Removable devices support is a separate task as well. 4. IMO you should preserve the low-level flash access interface and the request-based infrastructure should yous it as the back-end. Is this possible? Or my understanding of smartmedia is incorrect? I thought it is accessible as bare NAND and you have to support its FTL in software.=20 Probably there are other tasks. I think you should work on these smaller tasks separately and make them go in one by one, instead of trying to put all together. --=20 Best regards, Artem Bityutskiy (=D0=91=D0=B8=D1=82=D1=8E=D1=86=D0=BA=D0=B8=D0=B9 =D0=90= =D1=80=D1=82=D1=91=D0=BC)