Re: [U-Boot-Users] help - u-boot header & compression

3 Apr 2008

      Il giorno mer, 02/04/2008 alle 14.57 -0700, Avinash Vijayvergia ha
scritto:
...
Hi Luigi
Thank you for your mail and comments. I should have explain why I want
to compress u-boot. My target processor is Atmel AT91SAM9260. I am
having a 64Mb Dataflash which is interfaced on SPI bus. The Atmel ARM9
copies the first 4kB to internal SRAM and then boots from there. So we
need a loader of size <4kb which will be copied to SRAM. I have got
this loader. This loader will invoke u-boot, and u-boot will invoke
kernel. So I can compress loader and it will still work.
I'll compare nrv2b and lzma and then will be in a better position to
comment. I chose nrv2b because I need a compression algo which can be
as small as 600B (I have size restriction of 4kB).
Ok. Now I understand the problem. U-boot is a pure binary file, you need
to compile it fixing the TEXT_BASE address in order to fit your RAM.
Your "pre-bootloader" should setup the ram and the dataflash in order to
decompress/copy u-boot (vetctors+text+data) from the dataflash space
addresses to the ram addresses. After the copy/decompress just jump to
u-boot address. To achieve this you needn't to know the u-boot header
structure.
You should analyze the board/atmel/at91rm9200dk/u-boot.lds and
cpu/arm920t/start.S files  to understand how u-boot works (at
initialization time).
Best regards,
luigi
...
Thanks
Avinash
----- Original Message ----
From: Luigi 'Comio' Mantellini luigi.mantellini@idf-hit.com
To: Avinash Vijayvergia avinashs36@yahoo.com
Cc: u-boot-users@lists.sourceforge.net
Sent: Wednesday, April 2, 2008 2:37:20 PM
Subject: Re: [U-Boot-Users] help - u-boot header & compression
Hi Avinash,
see inline.
Il giorno mer, 02/04/2008 alle 14.26 -0700, Avinash Vijayvergia ha
scritto:
...
Hi LuigI
...
Thank you for your mail. I actually have two questions: 
     1. What is the format of u-boot header? Can you refer me to
        some documentation?
What do you intend for "u-boot header"? U-boot uses the uImage format
for the kernels images. You can check the file include/image.h (row
175) to understand the (old) uImage format. See this link: 
http://www.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=blob;f=include/image.h;...
...
 1. I want to compress u-boot. I have picked up nrv2b.c from
    Koders.com which is in use by many people :). I couldn't
    understand how it does encoding and decoding. I wanted to
    use this algo and do compression and decompression of my
    binaries. You can search google for nrv2b.c and you will get
    it from Koder.com. 

U-boot is the object code, the bootloader... how can you compress it?
it is a non-sense for me. Anyway, if you need to compress the kernel
image, you need to use the uImage format and the utility mkimage (see
tools directory). I recently posted a patch to support the lzma
compression algorithm (that works better than bzip2 and gzip): you can
search in the mailing list archive to retrieve this patch.
Are you sure that nrv2b is better than powerful lzma or bzip2? Do you
have benchmarks on this point? If you demonstrate me that nrv2b is a
good choice I can consider to make the patch for the community... I
have an application that has a very small flash memory... nrv2b should
be a choice...
Best regards,
luigi
...
Thanks for your help
Avinash
----- Original Message ----
From: Luigi 'Comio' Mantellini luigi.mantellini@idf-hit.com
To: Avinash Vijayvergia avinashs36@yahoo.com
Cc: u-boot-users@lists.sourceforge.net
Sent: Wednesday, April 2, 2008 2:19:36 PM
Subject: Re: [U-Boot-Users] help - u-boot header & compression
Hi Avinash,
I'm not undestanding if you want compress the U-Boot code or if you
want compress the uImage image.
Anyway, I don't know the nrv2b algorithm, can you give me any links?
thanks,
luigi
Il giorno mer, 02/04/2008 alle 13.54 -0700, Avinash Vijayvergia ha
scritto:
...
Hi All
I am working on AT91SAM9260 ARM9 core. I have very small flash
memory and hence need to compress the u-boot. I have picked nrv2b
algo for that. Can someone suggest me how to put the compression
info in the u-boot header. I want to know the details of u-boot
header too.
Thanks
Avinash

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E-mail:
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You rock. That's why Blockbuster's offering you one month of
Blockbuster Total Access, No Cost.
Ing. Luigi Mantellini
Industrie Dial Face S.p.A.
Via Canzo, 4 
20068 Peschiera Borromeo (MI)
Tel.: +39 02 5167 2813
Fax: +39 02 5167 2459
E-mail:
luigi.mantellini@idf-hit.com

You rock. That's why Blockbuster's offering you one month of
Blockbuster Total Access, No Cost.
Ing. Luigi Mantellini
Industrie Dial Face S.p.A.
Via Canzo, 4 
20068 Peschiera Borromeo (MI)
Tel.: +39 02 5167 2813
Fax: +39 02 5167 2459
E-mail: luigi.mantellini@idf-hit.com