[U-Boot-Users] Re: My 3 patches

[U-Boot-Users] Re: My 3 patches

[luo.jinhua]

Hi, Wolfgang.

How about my 3 patches? I'm looking forward to your reply. Thanks.

By the way, SBC-2410X board is made by friendly-arm, a chinese corporation. 
Here is a manual webpage for SBC-2410X (in Chinese):
http://www.arm9.net/matrix-v.asp

Recently, I am working on making U-Boot boot from nand on SBC-2410X board. Do
you think it is meaningful? In my opinion, nand flash has at least advantages
below:
1. nand flash is cheaper than nor flash.
2. nand flash is bigger than nor flash in size.
We can boot from nand flash, meanwhile it serves as data rom too. Nor flash
seems redundancy on the board.

Of course, nor flash is popular yet. No wonder that U-Boot considers nor flash
as boot rom by default. But, why SAMSUNG's S3C2410X owns builtin "boot from
nand" function? It hints.

"Recently, a NOR flash memory gets high in price while an SDRAM and a NAND
flash memory get moderate,
motivating some users to execute the boot code on a NAND flash and execute the
main code on an SDRAM.

S3C2410X boot code can be executed on an external NAND flash memory. In order
to support NAND flash boot
loader, the S3C2410X is equipped with an internal SRAM buffer called
?Steppingstone?. When booting, the first 4
KBytes of the NAND flash memory will be loaded into Steppingstone and the boot
code loaded into
Steppingstone will be executed."

--quoted from S3C2410X's datasheet.

Correspondingly, YAFFS, a NAND-flash friendly filing system, will be a good
choice to be added into U-Boot.
More detail:
http://www.aleph1.co.uk/armlinux/projects/

Best regards,
 
luo.jinhua

----------
JinHua Luo, GuangDong Linux Center, <luo.jinhua@gd-linux.com>

[U-Boot-Users] Re: My 3 patches

[Wolfgang Denk]

In message <20050906012549.M16097@gd-linux.com> you wrote:
> 
> How about my 3 patches? I'm looking forward to your reply. Thanks.

They are sitting in my queue waiting to be  reviewed  and  eventually
applied or rejected. Please be patient.

> Here is a manual webpage for SBC-2410X (in Chinese):
> http://www.arm9.net/matrix-v.asp

Is there an English manual, too?

> Recently, I am working on making U-Boot boot from nand on SBC-2410X board. Do
> you think it is meaningful? In my opinion, nand flash has at least advantages

This can be an issue if you have really high volumes of  your  boards
and   try   to  minimize  the  production  cost  at  the  expense  of
reliability.

> ??Steppingstone??. When booting, the first 4
> KBytes of the NAND flash memory will be loaded into Steppingstone and the boot
> code loaded into
> Steppingstone will be executed."

Here you see the problem: you will need a separate first stage loader
to do all the low level initializations and then load U-Boot  to  RAM
like  it  has  been  implemented  on  some  other systems before. The
probelm is that all  comfort  you  have  witrh  U-Boot  during  board
bringup and U-Bootporting gets lost this way.

> Correspondingly, YAFFS, a NAND-flash friendly filing system, will be a good
> choice to be added into U-Boot.

Feel free to submit patches.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
We have found all life forms in the galaxy are  capable  of  superior
development.
	-- Kirk, "The Gamesters of Triskelion", stardate 3211.7