zener
Posts: 10
Joined: Sat May 05, 2012 9:19 am

Re: u-boot image?

Sat May 05, 2012 1:53 pm

Is there a u-boot image with a network driver available anywhere?

If it has serial port support and/or HDMI support it would be great. I would like to set it up to load the kernel over the network using tftp and boot a kernel with NFS support and mount the file system from my server.

Joe Schmoe
Posts: 4277
Joined: Sun Jan 15, 2012 1:11 pm

Re: u-boot image?

Sat May 05, 2012 2:07 pm

I'm not sure of the soundness of your original question, but somebody has already figured out a way to net-boot the Pi.  Search the forum to find it.

But, I think the bottom line is you still need (and always will need) something in the SD slot to get the processing rolling.  You can't get away from that.
And some folks need to stop being fanboys and see the forest behind the trees.

(One of the best lines I've seen on this board lately)

zener
Posts: 10
Joined: Sat May 05, 2012 9:19 am

Re: u-boot image?

Sat May 05, 2012 2:31 pm

I would like to put u-boot on a small SD card.

Is the boot sequence of the RPi described anywhere? I would assume that there is a driver for the SD card somewhere as well as an ext2/3 (or some other type of filesystem) driver.

Joe Schmoe
Posts: 4277
Joined: Sun Jan 15, 2012 1:11 pm

Re: u-boot image?

Sat May 05, 2012 4:38 pm

There is a thread entitled "config.txt" that describes (in and among lots of other things) the boot sequence.  I always point people to that thread when they ask about the boot sequence.

Regarding your assumptions (heh heh): Some have claimed (in this forum) that the Pi has no onboard firmware at all.  This is not quite true, because, obviously, it has to have something on board.  But in the Pi's case, it is very minimal (I think Dom stated that it was "a few Kb").  It is just enough to understand FAT and to "mount", read and transfer control to a file stored on the FAT partition.
And some folks need to stop being fanboys and see the forest behind the trees.

(One of the best lines I've seen on this board lately)

zener
Posts: 10
Joined: Sat May 05, 2012 9:19 am

Re: u-boot image?

Sat May 05, 2012 9:42 pm

Thanks I'll search for the thread.

That was my point: There has to be a driver for the SD card and something to support the file system in order to extract some boot file.

zener
Posts: 10
Joined: Sat May 05, 2012 9:19 am

Re: u-boot image?

Sun May 13, 2012 12:21 pm

I'll probably have to replace the kernel with a u-boot image.

Did somebody already compile a u-boot image for the RPi?

error404
Posts: 351
Joined: Wed Dec 21, 2011 11:49 pm

Re: u-boot image?

Sun May 13, 2012 7:31 pm

Getting Pi's networking into uBoot will be difficult. It's connected via USB, so first you will need a full USB stack, then a driver for the network device itself.

Max

Re: u-boot image?

Mon May 14, 2012 10:57 am

error404 wrote:Getting Pi's networking into uBoot will be difficult. It's connected via USB, so first you will need a full USB stack, then a driver for the network device itself.
There is some USB stack support for uBoot: http://git.denx.de/?p=u-boot/u-boot-usb.git;a=summary
No idea if it is supports a flavor compatible with the Raspberry though.

Even includes a smsc95xx.c at: http://git.denx.de/?p=u-boot/u-boot-usb ... rs/usb/eth
So there may even be network device support.


Still need the SD card for the gpu blob and loader though. So there's little practical use for PXE. Easier to just put the Linux kernel on the SD card and mount the root file system through NFS or another protocol.

Zinahe
Posts: 16
Joined: Sun Jan 29, 2012 11:56 pm

Re: u-boot image?

Thu Jun 14, 2012 9:46 pm

I beg to differ here. Once we get u-boot working with network support; then so long with swapping SD cards. In fact, you only need one SD card from that point on. This in effect would allow one to control in software which image it will load on its next boot. Or am I missing something ? May be.

obarthelemy
Posts: 1399
Joined: Tue Aug 09, 2011 10:53 pm

Re: u-boot image?

Fri Jun 15, 2012 3:05 am

You're missing that you can do that without u-boot, with a few scripts to change config.txt so that the Pi looks for its kernel and rootfs where you want it too, and reboots.
This does require a reboot so it's less elegant than u-boot, but it's also a lot less work.

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jecxjo
Posts: 158
Joined: Sat May 19, 2012 5:22 pm
Location: Minneapolis, MN (USA)

Re: u-boot image?

Fri Jun 15, 2012 3:43 am

Max wrote: There is some USB stack support for uBoot: http://git.denx.de/?p=u-boot/u-boot-usb.git;a=summary
No idea if it is supports a flavor compatible with the Raspberry though.

Even includes a smsc95xx.c at: http://git.denx.de/?p=u-boot/u-boot-usb ... rs/usb/eth
So there may even be network device support.
Yes there is both USB and Network support in u-boot, though I've never looked to see if the USB support was anything more than mounting image files from a stick. TFTP support is in u-boot which would allow you to boot without a kernel or RFS on the SD card. Setup is very simple.
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Arch1mede
Posts: 6
Joined: Mon Jun 11, 2012 12:08 am

Re: u-boot image?

Mon Jun 25, 2012 4:09 am

jecxjo wrote:
Max wrote: There is some USB stack support for uBoot: http://git.denx.de/?p=u-boot/u-boot-usb.git;a=summary
No idea if it is supports a flavor compatible with the Raspberry though.

Even includes a smsc95xx.c at: http://git.denx.de/?p=u-boot/u-boot-usb ... rs/usb/eth
So there may even be network device support.
Yes there is both USB and Network support in u-boot, though I've never looked to see if the USB support was anything more than mounting image files from a stick. TFTP support is in u-boot which would allow you to boot without a kernel or RFS on the SD card. Setup is very simple.
I thoght I would make mention of this site which looks like the author is doing the same thing:

http://kernelnomicon.org/

rav99
Posts: 2
Joined: Fri Jul 18, 2014 5:08 am

Re: u-boot image?

Mon Jul 28, 2014 1:26 pm

I have setup the netboot environment for rpi to boot kernel from tftp server and root filesystem to boot from NFS server configured on same machine.
NFS is working but when I tried to remove a file named r.txt it returns error "read only filesystem"
however I have put rw permissions in /etc/export file and in rpi's boot file cmdline.txt
but it still gives error
And how I am supposed to get uboot prompt in rpi to configure environment variables ??

User avatar
mahjongg
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Location: South Holland, The Netherlands

Re: u-boot image?

Mon Jul 28, 2014 1:34 pm

u-boot is simply not the appropriate tool for the job, its written for x86 systems using a normal BIOS, the PI has neither.

you need something like berry boot instead.

drgeoff
Posts: 9736
Joined: Wed Jan 25, 2012 6:39 pm

Re: u-boot image?

Mon Jul 28, 2014 1:43 pm

mahjongg wrote:]u-boot is simply not the appropriate tool for the job, its written for x86 systems using a normal BIOS, the PI has neither.
Rubbish.

Many home routers, set-top boxes, media players etc have u-boot and they don't have x86 processors; usually ARM or MIPS.

From http://git.denx.de/?p=u-boot.git;a=blob ... ME;hb=HEAD

"#
# (C) Copyright 2000 - 2013
# Wolfgang Denk, DENX Software Engineering, [email protected].
#
# SPDX-License-Identifier: GPL-2.0+
#

Summary:
========

This directory contains the source code for U-Boot, a boot loader for
Embedded boards based on PowerPC, ARM, MIPS and several other
processors, which can be installed in a boot ROM and used to
initialize and test the hardware or to download and run application
code."

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