From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-out.m-online.net (mail-out.m-online.net [212.18.0.9]) by ozlabs.org (Postfix) with ESMTP id AD7B0DDEF6 for ; Thu, 26 Apr 2007 18:18:31 +1000 (EST) Message-ID: <4630611C.4060902@grandegger.com> Date: Thu, 26 Apr 2007 10:21:48 +0200 From: Wolfgang Grandegger MIME-Version: 1.0 To: Sergei Shtylyov Subject: Re: Flat device tree definitions for FLASH and MTD partitioning References: <4618D400.8050003@grandegger.com> <4618DBEF.30307@ru.mvista.com> <4618DE4A.4020404@ru.mvista.com> <462F4FD1.6080900@grandegger.com> <462F592F.7000409@ru.mvista.com> <462F5F86.3060309@grandegger.com> <462F6707.80502@ru.mvista.com> In-Reply-To: <462F6707.80502@ru.mvista.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: linuxppc-embedded@ozlabs.org List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sergei Shtylyov wrote: > Hello. > > Wolfgang Grandegger wrote: > >>>>>>> are there already some thought or even example code on how to >>>>>>> define Flash memory and MTD partitions in the DTS. This would >>>>>>> avoid the ackward MTD partitioning via static structure or boot >>>>>>> line argument and could be done in a generic way. > >>>>>> See Documentation/powerpc/booting-without-of.txt and >>>>>> drivers/mtd/physmap_of.c for what's been already done. > >>>>> I meant drivers/mtd/maps/physmap_of.c > >>>> I had a closer look to this driver. Unfortunately, it can not handle >>>> yet multiple FLASH banks. This could be achieved with an additional >>>> property "bank_count". What do you think? > > Please use hyphen, not underscore in property names ("device_type" > seems an only exception from this rule). Yes, I know and I also wondered why an "_" is used for the device type. >>> I'm not sure what banks you're talking about -- note that this >>> driver is equivalen in functionality to the plain 'physmap' driver >>> and there's inherited "bank-width" property that handles flash banking. > >> Yes, I know. Nevertheless the driver cannot handle flash regions >> composed of more than on FLASH bank because we need to probe every >> bank. Search for "BANK" in drivers/mtd/maps" to understand what I mean. > > Hm, from what I could see, those banks are separate maps registered to > MTD subsys separately. > What's the point of adding a count property when we simply can define > multiple "rom" devices? To complete this thread, physmap_of can map _one_ FLASH region composed of one or more FLASH banks. But it currently cannot map more than _one_ FLASH region. It would be nice to extend it for multiple FLASH definitions (could code it when time permits). Wolfgang.