From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from semihalf.com (semihalf.com [206.130.101.55]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 4D03CDDFB4 for ; Wed, 13 May 2009 19:00:09 +1000 (EST) From: Piotr =?iso-8859-2?q?Zi=EAcik?= To: John Rigby Subject: Re: [PATCH 06/12] mpc5121: Added NAND Flash Controller driver. Date: Wed, 13 May 2009 10:41:45 +0200 References: <1241640919-4650-1-git-send-email-wd@denx.de> <1241640919-4650-7-git-send-email-wd@denx.de> <4b73d43f0905072030n1b014dafmea840387ab0f3a6d@mail.gmail.com> In-Reply-To: <4b73d43f0905072030n1b014dafmea840387ab0f3a6d@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-2" Message-Id: <200905131041.45944.kosmo@semihalf.com> Cc: linuxppc-dev@ozlabs.org, linux-mtd@lists.infradead.org, Wolfgang Denk List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , =46riday 08 May 2009 05:30:15 John Rigby napisa=B3(a): > Did you choose to not support hardware ECC so you could use the spare are= a? > The original driver only supported hardware ECC but unfortuneatly the > hardware ECC includes the spare area so the spare area cannot be written > separately. In short yes. There are fundamental problems which you described. Flash=20 filesystems expect that ECC is calculated from main area only and writes to= =20 spare area not change it. MPC5121 NAND flash controller calculates ECC from= =20 both areas except few bytes holding ECC. This makes flash filesystems=20 unusable when we turn on hardware ECC. This could be fixed by disabling spare area usage in flash filesystems but this probably requires changes in the MTD/filesystem infrastructure. =2D-=20 Best Regards. Piotr Zi=EAcik