Re: Example of ARM based linux board using initramfs and serial console
--- On Fri, 7/11/08, Thomas Charron <[EMAIL PROTECTED]> wrote:
> From: Thomas Charron <[EMAIL PROTECTED]>
> Subject: Re: Example of ARM based linux board using initramfs and serial
> console
> > > says it can be a root FS by the kernel.
> > We're still talking Linux, right?
> (The kernel will panic if it then cannot
> find an initial
> > program to start, but it will still mount the
> filesystem first.)
> > You may be thinking of the "rdev" field in
> the kernel boot image
> > file. It gives major and minor numbers for the
> default root device,
> > which are used if you don't specify a
> "root=" argument on the kernel
> > command line.
>
> I was talking specifically about an initramfs, which
> specifically
> uses cpio. initramfs.c checks for a magic flag in the
I would recommend "Understanding the Linux Kernel" and "Linux Kernel
Development Second Edition"
kernel/init
do_mounts.h do_mounts_md.cKconfig Makefile version.o
do_mounts.cdo_mounts_initrd.c initramfs.c main.c
do_mounts_devfs.cdo_mounts_rd.c version.c
These files and kernel initialization is explained in these references. Very
little if any ARM specific dependencies here.
grep -i ARM *
Binary file built-in.o matches
Binary file do_mounts_initrd.o matches
Binary file do_mounts.o matches
Binary file do_mounts_rd.o matches
Binary file initramfs.o matches
Kconfig:default y if ARM || H8300
Kconfig:config OBSOLETE_MODPARM
main.c: printk("early_parm_test: %s\n", rest ?: "(null)");
Binary file main.o matches
My own project had a generous block of DDR memory for the creation of this
ramfs.
Michael Nolin
Embedded Solutions Unlimited, LLC
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Re: Example of ARM based linux board using initramfs and serial console
On 7/11/08, Ben Scott <[EMAIL PROTECTED]> wrote: > On Fri, Jul 11, 2008 at 11:53 AM, Thomas Charron <[EMAIL PROTECTED]> wrote: > > There IS something that I can't recall the exact specifics of, but > > it's along the lines of a 'magic identifier' in the filesystem that > > says it can be a root FS by the kernel. > We're still talking Linux, right? > To the best of my knowledge, there is no such thing. Any filesystem > can be mounted as a root filesystem. There's no magic in the > filesystem. (The kernel will panic if it then cannot find an initial > program to start, but it will still mount the filesystem first.) > You may be thinking of the "rdev" field in the kernel boot image > file. It gives major and minor numbers for the default root device, > which are used if you don't specify a "root=" argument on the kernel > command line. I was talking specifically about an initramfs, which specifically uses cpio. initramfs.c checks for a magic flag in the header which tells the kernel this is indeed a cpio compressed filesystem, specifically for mounting as the initial root filesystem by the kernel. Sorry I wasn't more specific when I said 'filesystem', perhaps I should have clarified with 'initramfs filesystem'. -- -- Thomas ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Example of ARM based linux board using initramfs and serial console
On Fri, Jul 11, 2008 at 11:53 AM, Thomas Charron <[EMAIL PROTECTED]> wrote: > There IS something that I can't recall the exact specifics of, but > it's along the lines of a 'magic identifier' in the filesystem that > says it can be a root FS by the kernel. We're still talking Linux, right? To the best of my knowledge, there is no such thing. Any filesystem can be mounted as a root filesystem. There's no magic in the filesystem. (The kernel will panic if it then cannot find an initial program to start, but it will still mount the filesystem first.) You may be thinking of the "rdev" field in the kernel boot image file. It gives major and minor numbers for the default root device, which are used if you don't specify a "root=" argument on the kernel command line. -- Ben ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Example of ARM based linux board using initramfs and serial console
On 7/11/08, Alexander Wolfson <[EMAIL PROTECTED]> wrote: > This is what I am doing as well. > Usually there is a statically linked program in the /bin called busybox which > provides big chunk of expected command line functionality. > All the programms - bash, ash, ls, ping, ... are slinks to busybox (init as > well) and busybox checks ARGV[0] for the name that was used to call it and > acts accordingly. It still has to be part of some filesystem and this is > where the problem is. I am doing something wrong creating the initramfs and > linking it with the kernel or something is wrong with my busybox or this is > something else that I am not even think of. There IS something that I can't recall the exact specifics of, but it's along the lines of a 'magic identifier' in the filesystem that says it can be a root FS by the kernel. Forgive me for not recalling exactly what it is, and I have no time ATM to STFW for it. :-D -- -- Thomas ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
RE: Example of ARM based linux board using initramfs and serial console
Just as a simple sanity check, I'd test it without trying to overcomplicate things. Forget the symlinks to busybox; just rename the binary to /bin/sh, or whatever name busybox uses to decide to be a shell; then modify the test kernel to run /bin/sh instead of /sbin/init. That will at least prove that the kernel can successfully boot. And from that, you can try running by hand each command that your proposed initramfs is supposed to run automatically via init. By doing that, you should be able to identify where the init process was failing. On Fri, July 11, 2008 7:59 am, Alexander Wolfson said: > This is what I am doing as well. > Usually there is a statically linked program in the /bin called busybox > which provides big chunk of expected command line functionality. > > All the programms - bash, ash, ls, ping, ... are slinks to busybox (init > as well) and busybox checks ARGV[0] for the name that was used to call it > and acts accordingly. It still has to be part of some filesystem and this > is where the problem is. I am doing something wrong creating the initramfs > and linking it with the kernel or something is wrong with my busybox or > this is something else that I am not even think of. > > Alex > > -Original Message- > From: [EMAIL PROTECTED] on behalf of John Abreau > Sent: Thu 7/10/2008 5:59 PM > To: gnhlug-discuss@mail.gnhlug.org > Subject: RE: Example of ARM based linux board using initramfs and serial > console > > > On Thu, July 10, 2008 4:08 pm, Alexander Wolfson said: >> This is our own board based on our own chip which among other things has >> ARM926EJ-S (ARMv5TEJ) core. >> There is no BSP yet, no Flash or USB drivers - only limited access to >> the board over JTAG. We can boot the board up to the point when kernel >> dies because there is no init. This why I need initramfs now. >> > > > While i don't know the details, I understand that it's common practice > when porting to a new platform to use bash, or perhaps a simpler shell, > in place of init, as a first step to achieve an initial boot. > > > -- > John Abreau / Executive Director, Boston Linux & Unix > IM: [EMAIL PROTECTED] / [EMAIL PROTECTED] / [EMAIL PROTECTED] / [EMAIL > PROTECTED] > Email [EMAIL PROTECTED] / WWW http://www.abreau.net / PGP-Key-ID 0xD5C7B5D9 > PGP-Key-Fingerprint 72 FB 39 4F 3C 3B D6 5B E0 C8 5A 6E F1 2C BE 99 > > > -- > This message has been scanned for viruses and > dangerous content by MailScanner, and is > believed to be clean. > > ___ > gnhlug-discuss mailing list > gnhlug-discuss@mail.gnhlug.org > http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/ > > > -- > This message has been scanned for viruses and > dangerous content by MailScanner, and is > believed to be clean. > -- John Abreau / Executive Director, Boston Linux & Unix IM: [EMAIL PROTECTED] / [EMAIL PROTECTED] / [EMAIL PROTECTED] / [EMAIL PROTECTED] Email [EMAIL PROTECTED] / WWW http://www.abreau.net / PGP-Key-ID 0xD5C7B5D9 PGP-Key-Fingerprint 72 FB 39 4F 3C 3B D6 5B E0 C8 5A 6E F1 2C BE 99 -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
RE: Example of ARM based linux board using initramfs and serial console
This is what I am doing as well. Usually there is a statically linked program in the /bin called busybox which provides big chunk of expected command line functionality. All the programms - bash, ash, ls, ping, ... are slinks to busybox (init as well) and busybox checks ARGV[0] for the name that was used to call it and acts accordingly. It still has to be part of some filesystem and this is where the problem is. I am doing something wrong creating the initramfs and linking it with the kernel or something is wrong with my busybox or this is something else that I am not even think of. Alex -Original Message- From: [EMAIL PROTECTED] on behalf of John Abreau Sent: Thu 7/10/2008 5:59 PM To: gnhlug-discuss@mail.gnhlug.org Subject: RE: Example of ARM based linux board using initramfs and serial console On Thu, July 10, 2008 4:08 pm, Alexander Wolfson said: > This is our own board based on our own chip which among other things has > ARM926EJ-S (ARMv5TEJ) core. > There is no BSP yet, no Flash or USB drivers - only limited access to > the board over JTAG. We can boot the board up to the point when kernel > dies because there is no init. This why I need initramfs now. > While i don't know the details, I understand that it's common practice when porting to a new platform to use bash, or perhaps a simpler shell, in place of init, as a first step to achieve an initial boot. -- John Abreau / Executive Director, Boston Linux & Unix IM: [EMAIL PROTECTED] / [EMAIL PROTECTED] / [EMAIL PROTECTED] / [EMAIL PROTECTED] Email [EMAIL PROTECTED] / WWW http://www.abreau.net / PGP-Key-ID 0xD5C7B5D9 PGP-Key-Fingerprint 72 FB 39 4F 3C 3B D6 5B E0 C8 5A 6E F1 2C BE 99 -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/ ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
RE: Example of ARM based linux board using initramfs and serial console
On Thu, July 10, 2008 4:08 pm, Alexander Wolfson said: > This is our own board based on our own chip which among other things has > ARM926EJ-S (ARMv5TEJ) core. > There is no BSP yet, no Flash or USB drivers - only limited access to > the board over JTAG. We can boot the board up to the point when kernel > dies because there is no init. This why I need initramfs now. > While i don't know the details, I understand that it's common practice when porting to a new platform to use bash, or perhaps a simpler shell, in place of init, as a first step to achieve an initial boot. -- John Abreau / Executive Director, Boston Linux & Unix IM: [EMAIL PROTECTED] / [EMAIL PROTECTED] / [EMAIL PROTECTED] / [EMAIL PROTECTED] Email [EMAIL PROTECTED] / WWW http://www.abreau.net / PGP-Key-ID 0xD5C7B5D9 PGP-Key-Fingerprint 72 FB 39 4F 3C 3B D6 5B E0 C8 5A 6E F1 2C BE 99 -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
RE: Example of ARM based linux board using initramfs and serial console
Thank you, I never heard of that one before Alex -Original Message- From: Thomas Charron [mailto:[EMAIL PROTECTED] Sent: Thursday, July 10, 2008 5:44 PM To: Alexander Wolfson Cc: [EMAIL PROTECTED]; gnhlug-discuss@mail.gnhlug.org Subject: Re: Example of ARM based linux board using initramfs and serial console On Thu, Jul 10, 2008 at 5:41 PM, Thomas Charron <[EMAIL PROTECTED]> wrote: > The tool: Linux Target Image Builder http://www.bitshrine.org/ I should elaborate. the Linux Target Image Builder is actually not done by Freescale, it's an open source utility whos website is located at http://savannah.nongnu.org/projects/ltib -- -- Thomas ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Example of ARM based linux board using initramfs and serial console
On Thu, Jul 10, 2008 at 5:41 PM, Thomas Charron <[EMAIL PROTECTED]> wrote: > The tool: Linux Target Image Builder http://www.bitshrine.org/ I should elaborate. the Linux Target Image Builder is actually not done by Freescale, it's an open source utility whos website is located at http://savannah.nongnu.org/projects/ltib -- -- Thomas ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Example of ARM based linux board using initramfs and serial console
On Thu, Jul 10, 2008 at 5:13 PM, Alexander Wolfson <[EMAIL PROTECTED]> wrote: > Thanks, > I looked at the docs - unfortunately they don't have details I am > looking for - it is more a cook book. Source files + the davinci pdf > would be great. > I have seen a Gentoo's already. It uses a complicated build system so > details a sort of hidden. If you're looking for a BSP to actually look at, Freescale has several available, as well as a tool they utilize to allow customers using freescale chips (including ARM) to build their distros. The BSPs: http://www.freescale.com/webapp/sps/site/overview.jsp?nodeId=02VS0l320822D0033202A7 The tool: Linux Target Image Builder http://www.bitshrine.org/ -- -- Thomas ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
RE: Example of ARM based linux board using initramfs and serial console
Thanks, I looked at the docs - unfortunately they don't have details I am looking for - it is more a cook book. Source files + the davinci pdf would be great. I have seen a Gentoo's already. It uses a complicated build system so details a sort of hidden. Alex -Original Message- From: Thomas Charron [mailto:[EMAIL PROTECTED] Sent: Thursday, July 10, 2008 4:54 PM To: Alexander Wolfson Cc: [EMAIL PROTECTED]; gnhlug-discuss@mail.gnhlug.org Subject: Re: Example of ARM based linux board using initramfs and serial console On Thu, Jul 10, 2008 at 4:41 PM, Alexander Wolfson <[EMAIL PROTECTED]> wrote: > Is it possible to take a look at the code for DaVinci? > At least kernel configuration file and initramfs directory structure. > Or you have to pay 7K for the license? > I am afraid that I am missing some nuance, so I would like to have some > sanity check before starting a full blown debugging. Take a look at http://focus.ti.com/lit/an/spraah2a/spraah2a.pdf I think it has basically the 'Idiots Guide' that they use as an example. Another thing to read that may help is http://gentoo-wiki.com/HOWTO_Custom_Initramfs_From_Scratch -- -- Thomas ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Example of ARM based linux board using initramfs and serial console
On Thu, Jul 10, 2008 at 4:41 PM, Alexander Wolfson <[EMAIL PROTECTED]> wrote: > Is it possible to take a look at the code for DaVinci? > At least kernel configuration file and initramfs directory structure. > Or you have to pay 7K for the license? > I am afraid that I am missing some nuance, so I would like to have some > sanity check before starting a full blown debugging. Take a look at http://focus.ti.com/lit/an/spraah2a/spraah2a.pdf I think it has basically the 'Idiots Guide' that they use as an example. Another thing to read that may help is http://gentoo-wiki.com/HOWTO_Custom_Initramfs_From_Scratch -- -- Thomas ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
RE: Example of ARM based linux board using initramfs and serial console
Is it possible to take a look at the code for DaVinci? At least kernel configuration file and initramfs directory structure. Or you have to pay 7K for the license? I am afraid that I am missing some nuance, so I would like to have some sanity check before starting a full blown debugging. -Original Message- From: Michael Nolin [mailto:[EMAIL PROTECTED] Sent: Thursday, July 10, 2008 4:32 PM To: gnhlug-discuss@mail.gnhlug.org; Alexander Wolfson Subject: Re: Example of ARM based linux board using initramfs and serial console > > I would like to find a working example of initramfs on the > ARM based > board. > > > > > > > I am porting Linux to the ARM 926 based board. There are no > network or > Flash drivers available yet. No LCD is available yet as > well > > I tried to use initramfs just to test the board , etc. > > This is a new chip so hardware bugs are possible. > The Texas Instruments Davinci platform uses a ARM926 core. U-Boot with a Monta Vista Pro Linux kernel. I would start with U-Boot/arch/ARM to get started on a new evaluation platform. This platform was not free about 7K for the licenses, I thought this was a good value considering rolling your own from uCLinux.org is work. The hardware was only $500.00 I'm using an MMU less ARM966 with no OS, GNU Linux development environment . ARM embedded question might best be answered on some of the comp.arch.embedded.. GNUARM Yahoo groups? Michael Nolin Embedded Solutions Unlimited, LLC ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Example of ARM based linux board using initramfs and serial console
> > I would like to find a working example of initramfs on the > ARM based > board. > > > > > > > I am porting Linux to the ARM 926 based board. There are no > network or > Flash drivers available yet. No LCD is available yet as > well > > I tried to use initramfs just to test the board , etc. > > This is a new chip so hardware bugs are possible. > The Texas Instruments Davinci platform uses a ARM926 core. U-Boot with a Monta Vista Pro Linux kernel. I would start with U-Boot/arch/ARM to get started on a new evaluation platform. This platform was not free about 7K for the licenses, I thought this was a good value considering rolling your own from uCLinux.org is work. The hardware was only $500.00 I'm using an MMU less ARM966 with no OS, GNU Linux development environment . ARM embedded question might best be answered on some of the comp.arch.embedded.. GNUARM Yahoo groups? Michael Nolin Embedded Solutions Unlimited, LLC ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
RE: Example of ARM based linux board using initramfs and serial console
This is our own board based on our own chip which among other things has ARM926EJ-S (ARMv5TEJ) core. There is no BSP yet, no Flash or USB drivers - only limited access to the board over JTAG. We can boot the board up to the point when kernel dies because there is no init. This why I need initramfs now. Alex -Original Message- From: Thomas Charron [mailto:[EMAIL PROTECTED] Sent: Thursday, July 10, 2008 3:59 PM To: Alexander Wolfson Cc: gnhlug-discuss@mail.gnhlug.org Subject: Re: Example of ARM based linux board using initramfs and serial console On Thu, Jul 10, 2008 at 2:59 PM, Alexander Wolfson <[EMAIL PROTECTED]> wrote: > Hi all, > I would like to find a working example of initramfs on the ARM based board. > I am porting Linux to the ARM 926 based board. There are no network or Flash > drivers available yet. No LCD is available yet as well I'm confused. You're trying to make a full Linux system on an Arm-926 based board which doesn't already have a BSP which includes Linux? The kernel itself has run on the 926 for years. -- -- Thomas ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Example of ARM based linux board using initramfs and serial console
On Thu, Jul 10, 2008 at 2:59 PM, Alexander Wolfson <[EMAIL PROTECTED]> wrote: > Hi all, > I would like to find a working example of initramfs on the ARM based board. > I am porting Linux to the ARM 926 based board. There are no network or Flash > drivers available yet. No LCD is available yet as well I'm confused. You're trying to make a full Linux system on an Arm-926 based board which doesn't already have a BSP which includes Linux? The kernel itself has run on the 926 for years. -- -- Thomas ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Example of ARM based linux board using initramfs and serial console
Hi all, I just subscribed to the list and would like to say hello to everybody. I would like to find a working example of initramfs on the ARM based board. I am porting Linux to the ARM 926 based board. There are no network or Flash drivers available yet. No LCD is available yet as well I tried to use initramfs just to test the board , etc. This is a new chip so hardware bugs are possible. Unfortunately I never used intramfs before and was looking for a good doc or better an example. The closes I found beyond "/Documentation/filesystems/ ramfs-rootfs-initramfs.txt was on free-electrons.com . They were using framebuffer and Qemu no serial console I built initramfs file system using "buildroot" project. So far board hangs after getting to the point where I assume it tries to go to initramfs. I started instrument the kernel, etc. to see what is going on, but it would be nice to have a working example to know that at least I did not make any stupid mistake. Thanks, Alex ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
