[U-Boot-Users] Download of kernel Image through Serial Line.
Hi.
Just a beginner with U-Boot.
In my new project we are trying to use Linux and U-Boot.
The main problem I have is that I don't have any ethernet link on this card.
- Is it possible to configure U-Boot to make a download of the image using the serial line ? ( tftp over serial line or something like that )
- If it is not possible would it be a big work ?
- If I eventually manage to launch Linux, is it possible to have NFS over serial line ?
- What are the minima requests in terms of memory to run Linux ? - Minimum Ram Size - Minimum Flash Size if I don't use NFS ( full embeded application )
Thanks.
Chris
On Wed, 29 Jan 2003 Christophe.LINDHEIMER@fr.thalesgroup.com wrote:
- Is it possible to configure U-Boot to make a download of the image using
the serial line ? ( tftp over serial line or something like that )
Yes, you can download the images using kermit, for instance.
- If I eventually manage to launch Linux, is it possible to have NFS over
serial line ?
Well, not as a root file system. You can boot into a small RAM disk and set up a ppp link, though.
- What are the minima requests in terms of memory to run Linux ?
- Minimum Ram Size
- Minimum Flash Size if I don't use NFS ( full embeded application )
That depends on your hardware and software. Define "full embedded application". With 4MB RAM you can get started. Depending on what you need in the kernel (networking, for instance) this can become a little bit tight quickly.
Regards Marius
----------------------------------------------------------------------------- Marius Groeger SYSGO Real-Time Solutions AG mgroeger@sysgo.de Software Engineering Embedded and Real-Time Software www.sysgo.de Voice: +49-6136-9948-0 Am Pfaffenstein 14 www.osek.de FAX: +49-6136-9948-10 55270 Klein-Winternheim, Germany www.elinos.com
Marius Groeger wrote:
On Wed, 29 Jan 2003 Christophe.LINDHEIMER@fr.thalesgroup.com wrote:
- If I eventually manage to launch Linux, is it possible to have NFS
over serial line ?
Well, not as a root file system. You can boot into a small RAM disk and set up a ppp link, though.
Actually, it is possible to mount the root FS via NFS over PPP. We have done so for development purposes on some of our systems with no ethernet service ports. The performance is limited, but once a binary (and it's associated libraries) are cached into memory, the system is reasonably responsive.
The trick is to use an initrd with a linuxrc file that sets-up the PPP link. The "root=" command line argument should be "/dev/nfs" and either an "ip=" or "nfsroot=" line should be used. I can be more specific if someone wants more information.
John
On Wed, 29 Jan 2003, John W. Linville wrote:
Actually, it is possible to mount the root FS via NFS over PPP. We have done so for development purposes on some of our systems with no ethernet service ports. The performance is limited, but once a binary (and it's associated libraries) are cached into memory, the system is reasonably responsive.
The trick is to use an initrd with a linuxrc file that sets-up the PPP link. The "root=" command line argument should be "/dev/nfs" and either an "ip=" or "nfsroot=" line should be used. I can be more specific if someone wants more information.
Ah, right, that could be done. I forgot about this possibility. Cool.
Thanks, Marius
----------------------------------------------------------------------------- Marius Groeger SYSGO Real-Time Solutions AG mgroeger@sysgo.de Software Engineering Embedded and Real-Time Software www.sysgo.de Voice: +49-6136-9948-0 Am Pfaffenstein 14 www.osek.de FAX: +49-6136-9948-10 55270 Klein-Winternheim, Germany www.elinos.com
-- Original Message -- From: Christophe.LINDHEIMER@fr.thalesgroup.com To: u-boot-users@lists.sourceforge.net Subject: [U-Boot-Users] Download of kernel Image through Serial Line. Date: Wed, 29 Jan 2003 10:38:13 +0100
Hi.
Just a beginner with U-Boot.
In my new project we are trying to use Linux and U-Boot.
The main problem I have is that I don't have any ethernet link on this card.
- Is it possible to configure U-Boot to make a download of the image using
the serial line ? ( tftp over serial line or something like that )
- If it is not possible would it be a big work ?
You could use kermit binary download. Check for example chapter 4.10.5.3 of our DENX PPCBoot and Linux Guide at http://www.denx.de/doc/TQM8xxL.
- If I eventually manage to launch Linux, is it possible to have NFS over
serial line ?
This does not sound very promising to me. A root filesystem on a JFFS2 or CRAMFS partition might be the better option.
- What are the minima requests in terms of memory to run Linux ?
- Minimum Ram Size
4MB or better 8MB.
- Minimum Flash Size if I don't use NFS ( full embeded application )
4MB. For a resonable 'standard' Embedded Linux runtime environment for PowerPC including basic network support you need approx. the following space in Flash:
U-Boot : 120 KB Linux kernel : 600 KB RAMDisk image : 1 MB Root file-system on JFFS2: 2.5 MB
And development and debugging without network will be quite cumbersome, I imagine. A hardware debugger would be of great help also for image download. Abatron's BDI2000 is a _great_ tool.
Hope it helps,
Wolfgang.
participants (4)
-
Christophe.LINDHEIMER＠fr.thalesgroup.com -
John W. Linville -
Marius Groeger -
wolfgang.grandegger＠bluewin.ch