From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from DB3EHSOBE002.bigfish.com (db3ehsobe002.messaging.microsoft.com [213.199.154.140]) (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 BC160B6F70 for ; Fri, 19 Aug 2011 04:24:46 +1000 (EST) Message-ID: <4E4D58E6.7060706@freescale.com> Date: Thu, 18 Aug 2011 13:24:38 -0500 From: Scott Wood MIME-Version: 1.0 To: Matthieu CASTET Subject: Re: [PATCH v3] mtd/nand : workaround for Freescale FCM to support large-page Nand chip References: <1313634783-8855-1-git-send-email-b35362@freescale.com> <4E4D452C.7050805@parrot.com> In-Reply-To: <4E4D452C.7050805@parrot.com> Content-Type: text/plain; charset="ISO-8859-1" Cc: "linuxppc-dev@ozlabs.org" , "b35362@freescale.com" , "dwmw2@infradead.org" , "linux-mtd@lists.infradead.org" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 08/18/2011 12:00 PM, Matthieu CASTET wrote: > b35362@freescale.com a =E9crit : >> From: Liu Shuo >> >> Freescale FCM controller has a 2K size limitation of buffer RAM. In or= der >> to support the Nand flash chip whose page size is larger than 2K bytes= , >> we divide a page into multi-2K pages for MTD layer driver. In that cas= e, >> we force to set the page size to 2K bytes. We convert the page address= of >> MTD layer driver to a real page address in flash chips and a column in= dex >> in fsl_elbc driver. We can issue any column address by UA instruction = of >> elbc controller. >> > Why do you need to do that ? >=20 > When mtd send you a 4k page, why can't you write it by 2*2k pages write= ? That would be more complicated given the statefulness of the interface, for no real benefit. > Even better send the first 2K and then if your controller allow it send= the > remaining 2K without command/address phase. IIRC Shuo tried this first and couldn't make it work. -Scott From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from db3ehsobe002.messaging.microsoft.com ([213.199.154.140] helo=DB3EHSOBE002.bigfish.com) by canuck.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1Qu7Gn-0000ks-Ay for linux-mtd@lists.infradead.org; Thu, 18 Aug 2011 18:24:46 +0000 Message-ID: <4E4D58E6.7060706@freescale.com> Date: Thu, 18 Aug 2011 13:24:38 -0500 From: Scott Wood MIME-Version: 1.0 To: Matthieu CASTET Subject: Re: [PATCH v3] mtd/nand : workaround for Freescale FCM to support large-page Nand chip References: <1313634783-8855-1-git-send-email-b35362@freescale.com> <4E4D452C.7050805@parrot.com> In-Reply-To: <4E4D452C.7050805@parrot.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable Cc: "linuxppc-dev@ozlabs.org" , "b35362@freescale.com" , "dwmw2@infradead.org" , "linux-mtd@lists.infradead.org" List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 08/18/2011 12:00 PM, Matthieu CASTET wrote: > b35362@freescale.com a =E9crit : >> From: Liu Shuo >> >> Freescale FCM controller has a 2K size limitation of buffer RAM. In or= der >> to support the Nand flash chip whose page size is larger than 2K bytes= , >> we divide a page into multi-2K pages for MTD layer driver. In that cas= e, >> we force to set the page size to 2K bytes. We convert the page address= of >> MTD layer driver to a real page address in flash chips and a column in= dex >> in fsl_elbc driver. We can issue any column address by UA instruction = of >> elbc controller. >> > Why do you need to do that ? >=20 > When mtd send you a 4k page, why can't you write it by 2*2k pages write= ? That would be more complicated given the statefulness of the interface, for no real benefit. > Even better send the first 2K and then if your controller allow it send= the > remaining 2K without command/address phase. IIRC Shuo tried this first and couldn't make it work. -Scott