From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from TX2EHSOBE003.bigfish.com (tx2ehsobe002.messaging.microsoft.com [65.55.88.12]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (Client CN "mail.global.frontbridge.com", Issuer "Microsoft Secure Server Authority" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id 5C184B6F99 for ; Tue, 13 Dec 2011 13:42:37 +1100 (EST) Message-ID: <4EE6BC9B.4000602@freescale.com> Date: Tue, 13 Dec 2011 10:46:51 +0800 From: LiuShuo MIME-Version: 1.0 To: Scott Wood Subject: Re: [PATCH 3/3] mtd/nand : workaround for Freescale FCM to support large-page Nand chip References: <1322973098-2528-1-git-send-email-shuo.liu@freescale.com> <1322973098-2528-3-git-send-email-shuo.liu@freescale.com> <4EDEAEB9.6020703@freescale.com> <1323724195.2297.11.camel@koala> <4EE66EFE.1050608@freescale.com> <1323724784.2297.20.camel@koala> <4EE6725C.3050706@freescale.com> In-Reply-To: <4EE6725C.3050706@freescale.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Cc: Artem.Bityutskiy@nokia.com, dedekind1@gmail.com, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, shuo.liu@freescale.com, linux-mtd@lists.infradead.org, akpm@linux-foundation.org, dwmw2@infradead.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , =E4=BA=8E 2011=E5=B9=B412=E6=9C=8813=E6=97=A5 05:30, Scott Wood =E5=86=99= =E9=81=93: > On 12/12/2011 03:19 PM, Artem Bityutskiy wrote: >> On Mon, 2011-12-12 at 15:15 -0600, Scott Wood wrote: >>> NAND chips come from the factory with bad blocks marked at a certain >>> offset into each page. This offset is normally in the OOB area, but >>> since we change the layout from "4k data, 128 byte oob" to "2k data, = 64 >>> byte oob, 2k data, 64 byte oob" the marker is no longer in the oob. = On >>> first use we need to migrate the markers so that they are still in th= e oob. >> Ah, I see, thanks. Are you planning to implement in-kernel migration o= r >> use a user-space tool? > That's the kind of answer I was hoping to get from Shuo. :-) OK, I try to do this. Wait for a couple of days. -LiuShuo > Most likely is a firmware-based tool, but I'd like there to be some way > for the tool to mark that this has happened, so that the Linux driver > can refuse to do non-raw accesses to a chip that isn't marked as having > been migrated (or at least yell loudly in the log). > > Speaking of raw accesses, these are currently broken in the eLBC > driver... we need some way for the generic layer to tell us what kind o= f > access it is before the transaction starts, not once it wants to read > out the buffer (unless we add more hacks to delay the start of a read > transaction until first buffer access...). We'd be better off with a > high-level "read page/write page" function that does the whole thing > (not just buffer access, but command issuance as well). > > -Scott