[U-Boot] working with loadb & bootm on u-boot-v2 for imx27ads Board

[Nishanth Menon <menon.nishanth@gmail.com>]

Lejin K Joy said the following on 09/25/2008 05:06 AM:
> I want to load the Linux Kernel Zimage on to RAM. As per the documentation
> we have used the following command to load zImage using Kermit protocol.
>
> " U-boot-v2> loadb -c zImage "
>
> (Also tried " U-boot-v2> loadb -f zImage ")
>
> Which successfully downloads zimage to the file with default offset set as
> 0x00000000.....
>   
U-Boot V2 uses a filesystem. when you did loadb -c -f zImage, it
downloaded the image to the file called zImage. zImage is stored within
the ramfs filesystem. (the concepts are very similar to an OS with
restrictions). This is slightly different from what you want to achieve
I think.
> a) But I am not able to understand to which location in RAM this image is
> written to? b) Please let me know how exactly to load kernel image to
> specific location on RAM?
>   
Look for the device node which shows the RAM/NOR/NAND you need. this
might be /dev/mem or (in my OMAP3430 case) /dev/ram0 - also see "help
loadb". Loadb takes the following options:
-f file - where to download to
-o offset - what offset to download - defaults to 0
-b baud - baudrate at which to download - defaults to console baudrate
-c - Create file if it is not present - default disabled
In your case, lets say: your ram starts at 0x80000000 and is denoted by
/dev/ram0. If you want to download to offset 0x3000 in ram, you can do
loadb -f /dev/ram0 -o 0x3000. this will essentially download to 0x80003000.

+ you now have the flexibility of downloading straight to NOR, NAND or
to even a file within u-boot v2's ramfs!! - so you can store and share
commonly used scripts modules etc.. tons of similar flexibility exists.
> c) Also how we can change the default location since the user is not given
> an option to mention the address.
>   
as explained above.
> d) How to load the file " zImage" to RAM?
>   
if you want to copy a file from ramfs to a "specific location" just do
the cp command!
> I was intending to do the following steps :
>
> 	>> loadb 0x100000 zimage
> 	>> loadb 0x1000000 ramdisk.gz 
> 	>> bootm 0x100000 0x1000000
>
> Please help me out as I am using U-boot-V2 for the first time.
>   
Does the above explanation help? in u-boot-v2, you can infact run "help
<command name>" or do a make docs And if you have graphviz latex etc
installed, you will get a html documentation in Documentation/html.

Note: I created a few useful platform independent tools for U-boot
(should work for both U-boot v2 and V1). they are available in [1].
>
> -----Original Message-----
> From: u-boot-bounces at lists.denx.de [mailto:u-boot-bounces at lists.denx.de] On
> Behalf Of Lejin K Joy
> Sent: Tuesday, September 23, 2008 9:49 PM
> To: 'Robert Schwebel'; 'Sascha Hauer'
> Cc: u-boot at lists.denx.de
> Subject: Re: [U-Boot] u-boot-v2 for imx27 Board
>   
Try not to top post. see [2] and mailing list ettiquette.
Regards,
Nishanth Menon

[1] http://code.google.com/p/omap-u-boot-utils/
[2] http://en.wikipedia.org/wiki/Posting_style