From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [84.204.75.166] (helo=shelob.oktetlabs.ru) by canuck.infradead.org with esmtps (Exim 4.54 #1 (Red Hat Linux)) id 1FPEb1-0007NY-Of for linux-mtd@lists.infradead.org; Fri, 31 Mar 2006 03:03:12 -0500 Message-ID: <442CE217.8080103@yandex.ru> Date: Fri, 31 Mar 2006 12:02:31 +0400 From: "Artem B. Bityutskiy" MIME-Version: 1.0 To: Alexander Belyakov References: <442B9FA5.9070901@ru.mvista.com> <442BF839.8060402@intel.com> <1143733184.3579.47.camel@sauron.oktetlabs.ru> <442CD50A.6070006@intel.com> In-Reply-To: <442CD50A.6070006@intel.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: "Korolev, Alexey" , Vitaly Wool , "Kutergin, Timofey" , linux-mtd@lists.infradead.org Subject: Re: [PATCH/RFC] MTD: Striping layer core List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Alexander Belyakov wrote: >> Well, probably this is a perversion and is not needed in reality, but >> still. I conceive it like this. Yo have 2 flashes. You as usually, >> calculate the resulting eraseblock size. You see at the minimal I/O unit >> size of both flashes and similarly calculate the resulting minimal I/O >> size. So that's it. You'll end up with a though perverted, but still a >> striped MTD device. > > First problem in case of striping NOR and NAND is a question about type > of striped device. Should we report it as NOR or as NAND. I believe it > is important for clients to know about that. Imagine, for example, > device reported as NAND behaves as NOR or vice versa. Another problem is > a difference in operation speed. Apparently you won't get any > performance gain. These are only top of iceberg. Note that even plain > and simple mtdconcat is not supposed to work with flashes of different > types. Good question. I think you could report this is a striped device (introducing an MTD_STRIPED option). Also you may provide a stripe_get_info(struct mtd_info *mtd) function which will return a struct stripe_info object describing this striped device, including the components it consists of. -- Best Regards, Artem B. Bityutskiy, St.-Petersburg, Russia.