From mboxrd@z Thu Jan 1 00:00:00 1970 From: Detlev Zundel Date: Tue, 23 Jun 2009 11:25:32 +0200 Subject: [U-Boot] Mips, U-Boot and ramdisk In-Reply-To: <4A3F9B62.5070107@sch.bme.hu> (Robert Hodaszi's message of "Mon, 22 Jun 2009 16:55:30 +0200") References: <4A3F9B62.5070107@sch.bme.hu> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Robert, > Can anybody help me? I'm working on this for a few days... > > I'm working on a custom developed board, with Au1200, and I'd like to > use the U-Boot as bootloader. I ported the U-Boot to my board, made a > Linux kernel image, and a ramdisk image. > > To try out the configuration, I burn the U-Boot image into the flash (it > works well), and after I start the board, it download the kernel image > and the ramdisk image through TFTP. I'm using the following two commands: > > tftp 81000000 uImage > tftp 81FFFFC0 uRamdisk > > I set the bootargs variable to: root=\dev\ram (I used: set bootargs > root=/dev/ram) root=/dev/ram is definitely correct. It was MS-DOS a while ago, which switched the '/'s to '\'s on stealing the hierarchical file system concept from Unix ;) > But when I'm trying to start the Linux with the > > bootm 81000000 81FFFFC0 > > the Linux can't find the ramdisk. It write out: > > Initrd not found or empty - disabling initrd > > But when I set its address into the bootargs (so the bootargs: > root=/dev/ram rd_start=0x82000000 rd_size=0x191160), it works well; it > successfully find the image, and can mount it. > > How does the U-Boot pass the ramdisk information? This is highly specific to the architecture. Looking into MIPS code, it an environment like datastructure is built and passes that to the kernel (lib_mips/bootm.c). > It sets some kind of environment variables in the bootm.c. Right, that's what I see also. > But it doesn't work for me. Why? I can't help you here, the best thing would be to debug this. Maybe the MIPS kernel changed the way the environment is passed? Cheers Detlev -- We have a live-manual. It's called emacs-devel at gnu.org. You can stick to just reading it, but you can skip to a specific chapter by simply sending an email asking for it ;-) -- Stefan Monnier -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-40 Fax: (+49)-8142-66989-80 Email: dzu at denx.de