[U-Boot-Users] uboot basics ?

[U-Boot-Users] uboot basics ?

[Ram]

Hi,
I am going through the uboot drivers code for smc91111 ethernet controller 
in uboot.

My Objective is to know how boot loader configures the ethernet controller.

This is for the first time i am going thru a boot loader code.

I have some doubts:

How does a boot loader know which device is connected. say i have connected 
the smc 91111 ethernet 
controller - how does it know it is smc91111 controller.

I think as soon as it detects the smc91111 controller is connected. it must 
configure that - i think the 
code in drivers/smc91111.c must be executed.

What will happen if there are 2 ethernet controllers in the board. how 
u-boot responds to this.

However, i am not following the code given in smc91111.c i really dont know 
what it is doing ?.

i have the data sheets with me and going thru it. i must admit i am totally 
confused.

Does anybody know what constitues configuring a ethernet controller and what 
the code does ?.

i would request you to kindly let me the flow in u-boot. from startup to 
configuring ind. devices.


Any description is available in this matter will be very useful. 


Any pointers in this matter is highly appreciated.


Thanks,


Regards,
Ram
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.denx.de/pipermail/u-boot/attachments/20050831/0bdc82d7/attachment.htm 

[U-Boot-Users] uboot basics ?

[Wolfgang Denk]

In message <8bf24776050830223673cd6b8e@mail.gmail.com> you wrote:
>
> How does a boot loader know which device is connected. say i have connected>  

U-Boot is stupid. It doesn't "know" anything. It just does  what  you
tell it.

> the smc 91111 ethernet 
> controller - how does it know it is smc91111 controller.

It doesn't know. It juist runs the code you configure into it.

> I think as soon as it detects the smc91111 controller is connected. it must>  

It doesn;t detect it. It just runs the init code if you configure it.

> What will happen if there are 2 ethernet controllers in the board. how 
> u-boot responds to this.

If just does what you configure...

> Does anybody know what constitues configuring a ethernet controller and wha> t 
> the code does ?.

I'd say such a question is off topic here. You are supposed to have a
deep understanding of the hardware and driver code when digging  into
boot loader code.

> i would request you to kindly let me the flow in u-boot. from startup to 
> configuring ind. devices.

Just start at the reset entry point and follow the code. Ther eis  no
easy way to understand it all.

> Any description is available in this matter will be very useful. 

Read the README and the manual.

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
Our business is run on trust.  We trust you will pay in advance.