From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756759AbaC0MWZ (ORCPT ); Thu, 27 Mar 2014 08:22:25 -0400 Received: from mail.karo-electronics.de ([81.173.242.67]:54351 "EHLO mail.karo-electronics.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753222AbaC0MWW convert rfc822-to-8bit (ORCPT ); Thu, 27 Mar 2014 08:22:22 -0400 Date: Thu, 27 Mar 2014 13:21:09 +0100 From: Lothar =?UTF-8?B?V2HDn21hbm4=?= To: Huang Shijie Cc: Fabio Estevam , Mark Rutland , Shawn Guo , Russell King , Pawel Moll , Arnd Bergmann , Ian Campbell , Artem Bityutskiy , , , , Rob Herring , , , Rob Landley , Kumar Gala , Brian Norris , David Woodhouse , Sascha Hauer , Shawn Guo Subject: Re: [PATCHv2 1/1] mtd: gpmi: make blockmark swapping optional Message-ID: <20140327132109.06258526@ipc1.ka-ro> In-Reply-To: <20140327095956.GA29623@localhost> References: <532BCFCC.4080205@freescale.com> <1395399017-19005-1-git-send-email-LW@KARO-electronics.de> <20140324095902.GB11377@localhost> <20140326095156.3e5585b8@ipc1.ka-ro> <5332AEE7.2040402@freescale.com> <20140326125502.0e8d0657@ipc1.ka-ro> <20140327095956.GA29623@localhost> Organization: Ka-Ro electronics GmbH X-Mailer: Claws Mail 3.8.1 (GTK+ 2.24.10; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Huang Shijie wrote: > > > Please see "Figure 12-13" in the 12.12.1.12: > > > "In order to preserve the BI (bad block information), flash updater > > > or gang programmer > > > applications need to swap Bad Block Information (BI) data to byte 0 of > > > metadata area for > > > every page before programming NAND Flash. ROM when loading firmware, > > > copies back > > > the value at metadata[0] to BI offset in page data. The following figure > > > shows how the > > > factory bad block marker is preserved." > > > > > The inspection of the BB markers is only a fallback for the case that > > there is no DBBT. From the same chapter that you quoted above: > > | ROM uses DBBT to skip any bad block that falls within firmware data > > | on NAND Flash device. > > | If the address of DBBT Search Area in FCB is 0, ROM will rely on > > | factory marked bad block markers to find out if a block is good or bad. > > > > Thus, even the boot ROM of i.MX28 can well live without blockmark > > swapping. > > Assume that there is a NAND block "A", and the A consist of 256 pages. > the uboot is burned to the "A", can occupy 6 pages: > > ----------------------------------------------------------------------------- > | page 0 | page 1 | page 2 | page 3 | page 4 | page 5 | ... | ... | page 255 | > ----------------------------------------------------------------------------- > > \-------------------------------------- ------------------------------------/ > V > "A" > > The DBBT is used to track if "A" is bad or not. > Assume we know that "A" is a good block, ROM then need to read out the uboot. > When the ROM needs to read out the 6 pages one by one. And each time the ROM read > the page, it should do the swapping for this page. > > In this case, the ROM will do the swapping six times. > > Please read the sector again, you will see the "every page" in it: > -------------------------------------------------------------------- > "In order to preserve the BI (bad block information), flash updater > or gang programmer applications need to swap Bad Block Information (BI) data to byte 0 of > metadata area for every page before programming NAND Flash. ROM when loading firmware, > copies back > -------------------------------------------------------------------- > I can assure you that the >100.000 i.MX28 based modules, that we sold up to now boot from NAND just fine without any block mark swapping in the U-Boot pages. Lothar Waßmann -- ___________________________________________________________ Ka-Ro electronics GmbH | Pascalstraße 22 | D - 52076 Aachen Phone: +49 2408 1402-0 | Fax: +49 2408 1402-10 Geschäftsführer: Matthias Kaussen Handelsregistereintrag: Amtsgericht Aachen, HRB 4996 www.karo-electronics.de | info@karo-electronics.de ___________________________________________________________