[ARMedslack] Hello

[Thorsten Mühlfelder]

Am Wednesday 16 March 2011 12:22:18 schrieb Davide:
> I look like it replaces the original uboot on mtd0, is that correct ?

I'm not sure anymore. I would have to investigate the script again first.

> While openwrt is using original uboot to start another version so that if
> you screw up you still have the original one to get things working again
> without need for jtag.

Yes, that's possible. AFAIK you just have to place the second u-boot to the 
NAND address where originally the kernel can be found. If it fails to load 
the second u-boot the first u-boot must be able to boot from usb to recover 
things. Otherwise without JTAG you are stuck, too.
IIRC on mikrocontroller.net the layout of the JTAG connector can be found.

> Just incase someone else needs it here is what the 2 versions of ubuut
> currently on my dockstar do: U-Boot 1.1.4 (Jul 16 2009 - 21:02:16) Cloud
> Engines (3.4.16)

Is this the original one?

> ext2load- load binary file from a Ext2 filesystem
> ext2ls  - list files in a directory (default /)

This one can load the kernel of an ext2 file system. But I did not see any USB 
capabilities.

> bootargs_root=root=/dev/mtdblock2 ro

It expects root on mtd2.

> bootcmd=nand read.e 0x800000 0x100000 0x40000; go 0x800000

It loads a kernel from NAND address 0x40000 to RAM and boots it:
> CE>> boot
>
> NAND read: device 0 offset 0x100000, size 0x40000
>
> Reading data from 0x100000 --   0% ...
>  262144 bytes read: OK
> ## Starting application at 0x00800000 ...


Second one:
> U-Boot 2010.09 (Mar 10 2011 - 00:51:16)
> Marvell-Sheevaplug
>
> SoC:   Kirkwood 88F6281_A0
> DRAM:  128 MiB
> NAND:  256 MiB
> *** Warning - bad CRC or NAND, using default environment


> fatinfo - print information about filesystem
> fatload - load binary file from a dos filesystem
> fatls   - list files in a directory (default /)

Support loading kernel of a FAT partition but not of ext2 (no problem).

> usb     - USB sub-system
> usbboot - boot from USB device

It supports loading the kernel from USB devices.

> bootcmd=${x_bootcmd_kernel}; setenv bootargs ${x_bootargs}
> ${x_bootargs_root}; ${x_bootcmd_usb}; bootm 0x6400000; bootdelay=3
> baudrate=115200
> ipaddr=169.254.254.243
> serverip=169.254.254.254

> x_bootargs=console=ttyS0,115200
> mtdparts=orion_nand:1M(u-boot),1M at 1M(second_stage_u-boot),3M at 2M(kernel),32M
>@5M(rootfs),219M at 37M(data) rw x_bootcmd_kernel=nand read 0x6400000 0x200000
> 0x300000
It loads a kernel from NAND address 0x300000...

> x_bootcmd_usb=usb start
... starts the usb system (no idea why) ....

> x_bootargs_root=root=/dev/mtdblock3 rw rootfstype=jffs2
... and expects the root file system on mtd3 as jffs2.


What you can do:
Prepare a USB stick with a FAT boot partition. Place the kernel on it. Use 
usbstart and fatload to load the kernel to the RAM.
Provide the right bootargs and your ARMed slack rootfs on the same USB stick.
And run bootcmd.



-- 
Thorsten Mühlfelder
Salix OS: www.salixos.org