mtd.rar_mtd _s3c2410 fs

*** The Linux MTD, JFFS HOWTO *** (work in progress, please contribute if you have anything) $Id: mtd-jffs-HOWTO.txt,v 1.16 2001/08/13 23:17:55 dwmw2 Exp $ Last Updated: <see CVS Id above> Compiled/Written By: Vipin Malik ([email protected]) Other author's contributions as noted in the text. **ABOUT: This document will attempt to describe setting up the MTD (Memory Technology Devices), DOC, CFI and the JFFS (Journaling Flash File System) under Linux versions 2.2.x and 2.4.x This is work in progress and (hopefully) with the help of others on the mtd and jffs mailing lists will become quite a comprehensive document. Please mail any comments/corrections/contributions to [email protected] Please DO NOT send questions to him directly, rather send them to the mailing lists (see below). **************************** NO WARRANTY ***************************** # This HOWTO is distributed in the hope that it will be useful, but # WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. # If you break something you get to keep both parts! Follow these # directions at YOUR OWN RISK. # See the GNU General Public License for more details. ********************************************************************** *** Getting Started: If you want to seriously design a project with MTD/JFFS please subscribe to the respective mailing lists. Both are managed by majordomo. MTD: To subscribe, see http://lists.infradead.org/mailman/listinfo/linux-mtd-cvs or send an email to [email protected] containing the line "subscribe" in the body. DO NOT SEND SUBSCRIBE REQUESTS TO THE LIST ITSELF, which is at [email protected]. JFFS: To subscribe, send an email to [email protected] containing the line "subscribe jffs-dev" in the body. DO NOT SEND SUBSCRIBE REQUESTS TO THE LIST ITSELF, which is at [email protected]. The home page for the two projects are located at: MTD/DOC/ http://www.linux-mtd.infradead.org/ JFFS http://developer.axis.com/software/jffs/ The MTD mail archive is at: http://www.linux-mtd.infradead.org/list-archive/ The JFFS mail archive is at: http://mhonarc.axis.se/jffs-dev/threads.html <blatant plug by author> A general, vendor agnostic, non commercial site for Embedded Linux Systems is at: http://www.EmbeddedLinuxWorks.com (Here you will find articles about using IDE flash disks in embedded systems, reports of JFFS/JFFS2 power fail reliability tests, tips on using JFFS systems in your design, details on how to boot the x86 Linux kernel from FLASH without using a BIOS and (hopefully in due course) a vibrant community of developers discussing issues related to embedded Linux with each other on the message boards ;) ** MTD Flash Device Database: ** In the above mentioned site, you will also find a MTD Flash device database. This database contains a list of flash devices successfully working with the MTD drivers. If you manage to get a particular flash device (or Disk On Chip etc.) to work with any MTD driver, please take a few minutes to enter the relevant info in this database for the benefit of future users. Anyone can make an entry or view any info there. Access the MTD Flash database directly at: http://www.embeddedLinuxWorks.com/db.html ** Power fail safe embedded database ** There is a seperate project (with its own mailing list) going on to develop a zero latency write, power fail safe (small) embedded database to use on JFFS2. Read more on why we need such a beast at: http://www.embeddedLinuxWorks.com/articles/db_project.html </blatant plug by author> *** Getting the latest code: The entire MTD/DOC/JFFS (and some utils) source code may be downloaded via anonymous CVS. Follow the following steps: 1.Make sure that you are root. 2. cd /usr/src 3. cvs -d :pserver:[email protected]:/home/cvs login (password: anoncvs) 4. cvs -d :pserver:[email protected]:/home/cvs co mtd This will create a dir called mtd under /usr/src You now have two options depending on what series of the Linux Kernel you want to work with. There is an extra step involved with the 2.2 series kernels as they do not have any MTD code in them. Note: Check under /dev/ If you do not have devices like mtd0,1,2 and mtdblock0,1,2 etc. run the MAKEDEV utility found under mtd/util as: #sh /usr/src/mtd/util/MAKEDEV This will create all the proper devices for you under /dev ** With 2.2.x series kernels: (Note that as far as I can tell, mtd and jffs does not work as modules under the 2.2.x series of kernels. If you want to do modules I would recommend that you upgrade to the 2.4.x series of kernels). Get the 2.2.17 or 2.2.18 kernel source code from your favorite source (ftp.kernel.org) and install the kernel under /usr/src/linux-2.2.x with /usr/src/linux being a symbolic link to your kernel source dir. Configure the kernel to your desired options (by doing a make config (or menuconfig or xconfig), and make sure that the kernel compiles ok. Download the mtd patch from: ftp://ftp.infradead.org/pub/mtd/patches Move the patch to /usr/src/linux and do patch -p1 < <patch file name here> Make sure that the patch was applied ok without any errors. This will add the mtd functionality to your basic kernel and bring the mtd code up-to date to the date of the patch. You have two choices here. You may do a make config and configure in mtd stuff with the current code or you may want to get the latest code from the cvs patched in. If you want the latest CVS code patched in follow the 2.4.x directions below. ** With 2.4.x series of kernels: If you want the latest code from CVS (available under /usr/src/mtd) do: 1. cd /usr/src/mtd/patches 2. sh patchin.sh /usr/src/linux This will create symbolic links from the /usr/src/linux/drivers/mtd/<files here> to the respective files in /usr/src/mtd/kernel/<latest files here> The same happens with /usr/src/linux/fs/jffs and /usr/src/linux/include/linux/mtd Now you have the latest cvs code available with the kernel. You may now do a make config (or menuconfig or xconfig) and config the mtd/jffs etc. stuff in as described below. *** Configuring MTD and friends for DOC in the Kernel: Do not use any mtd modules with the 2.2.x series of kernels. As far as I can tell, it does not work even if you can get it to compile ok. Modules work ok with the 2.4.x series of kernels. Depending on what you want to target you have some choices here, namely: *** 1. Disk On Chip Devices (DOC): For these, you need to turn on (or make into modules) the following: * MTD core support * Debugging (set the debug level as desired) * Select the correct DOC driver depending on the DOC that you have. (1000, 2000 or Millennium). Note that the CONFIG_MTD_DOC2000 option is a driver for both the DiskOnChip 2000 and the DiskOnChip Millenium devices. If you have problems with that you could try the alternative DiskOnChip Millennium driver, CONFIG_MTD_DOC2001. To get the DiskOnChip probe code to use the Millennium-specific driver, you need to edit the code in docprobe.c and undefine DOC_SINGLE_DRIVER near the beginning. * Unless you are doing something out of the ordinary, it shouldn't be necessary for you to enable the "Advanced detection options for DiskOnChip" option. * If you do so, you can specify the physical address at which to probe for the DiskOnChip. Normally, the probe code will probe at every 0x2000 bytes from 0xC8000 to 0xEE000. Changing the CONFIG_MTD_DOCPROBE_ADDRESS option will allow you to specify a single location to be probed. Note that your DiskOnChip is far more likely to be mapped at 0xD0000 than 0xD000. Use the real physical address, not the segment address. If you leave the address blank (or just don't enable the advanced options), the code will *auto probe*. This works quite well (at least for me). Try it first