From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sccrmhc15.comcast.net (unknown [63.240.77.85]) by ozlabs.org (Postfix) with ESMTP id C83E0679FB for ; Sat, 5 Aug 2006 01:53:00 +1000 (EST) Message-ID: <44D36D4B.90001@dlasys.net> Date: Fri, 04 Aug 2006 11:52:43 -0400 From: "David H. Lynch Jr." MIME-Version: 1.0 To: "Ned W. Rhodes" , jonandia@aotek.es Subject: Re: MTD Flash Howto ? References: <001a01c6b7d1$17dd6130$6201eed0@ssgpoweredge> In-Reply-To: <001a01c6b7d1$17dd6130$6201eed0@ssgpoweredge> Content-Type: text/plain; charset=ISO-8859-1 Cc: linuxppc-embedded@ozlabs.org Reply-To: dhlii@comcast.net List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Thanks; I looked at the Denx stuff that was a good start. But raised some questions: I have a single device. I presume that means it is 8 bits wide, and constitutes a single Bank. I guess I have to query the Hardware people, on that. What exactly drives CONFIG_MTD_I? and CONFIG_MTD_B? A hard disk partition is usually reflected by data structures (a partition table) written to the Disk. Am I correct in assuming that these are in drivers/mtd/maps. In my instance all the flash belongs to a single file system There is a single reserved block at the begining, but it is reflected in the filesystem structure not the partitioning. So as I understand things I have a single partition. When I ran menuconfig, I indicated that I did not need/had a single partitions - would that be the correct choice ? There is a platform ram "map" that seems to allow defining the flash region in a platform data structure - is that a viable alternative to a machine specific map file ? Is it limited to just RAM. Prior to loading a filesystem driver shouldn;'t I get some message indicating that mtd detected my specific type of flash ? or Is that queriable inside /proc ? Ned W. Rhodes wrote: > The book Building Embedded Linux Systems has a good section on the use of > flash file systems. > > When you boot, you will see something like this, depending on the type of > flash driver you have. Make sure you have defined your mtd map in > kernel/drivers/mtd/map. > > JFFS2 version 2.2. (NAND) (C) 2001-2003 Red Hat, Inc. > JFS: nTxBlock = 965, nTxLock = 7720 > > Then if you have the MTD partitions correctly identified, the kernel will > show you something like: > > CBG flash bank 0: Found 1 x16 devices at 0x0 in 16-bit bank > Intel/Sharp Extended Query Table at 0x0031 > Using buffer write method > cfi_cmdset_0001: Erase suspend on write enabled > Creating 2 MTD partitions on "CBG flash bank 0": > 0x00000000-0x01800000 : "ffw1" > 0x01800000-0x02000000 : "filesystem1" > > Once booted you can look at /proc/mtd and you should see the partitions > something like: > > [root@lbg ]# cat /proc/mtd > dev: size erasesize name > mtd0: 01800000 00020000 "ffw1" > mtd1: 00800000 00020000 "filesystem1" > > Your mileage may vary depending on the type of flash you have and all the > configuration options, but that is basically how to tell that things are > mapped and ready for use. > > Ned W. Rhodes > Software System Group > 703.812.5072 x100 > > -- Dave Lynch DLA Systems Software Development: Embedded Linux 717.627.3770 dhlii@dlasys.net http://www.dlasys.net fax: 1.253.369.9244 Cell: 1.717.587.7774 Over 25 years' experience in platforms, languages, and technologies too numerous to list. "Any intelligent fool can make things bigger and more complex... It takes a touch of genius - and a lot of courage to move in the opposite direction." Albert Einstein