[U-Boot-Users] Design Recommendation and Help with Issues

[Ben Warren]

Jatin Sharma wrote:
> I am running U-Boot version U-Boot 1.3.1-rc1 on my board that has a
> Broadcom network switch. My goal is to initialize this switch at the
> bootloader level and be able to tftpboot a Linux kernel from one of
> the ethernet ports of this switch.
>
> As _I_ understand, there are two ways to initialize the switch from u-boot.
>
> First
> =====
> Theory: Link the switch driver software with the u-boot.bin and flash
> it on the board. Switch driver's entry point would be called somewhere
> in u-boot to initialize it. Size of the u-boot.bin will increase and
> the u-boot partition on the NOR flash will need to be updated to
> accommodate the new binary size.
>
> Practice: After I linked the driver software with the u-boot.bin, the
> board didn't boot any further after u-boot got relocated to RAM with
> this following message:
> "Now running in RAM - U-Boot at: 0ff6d000"
>
> I did the following to link switch driver library (MDK_BLIBS) with
> u-boot in Makefile:
>
> $(obj)u-boot:	.........	
> 			--start-group $(__LIBS) $(MDK_BLIBS)--end-group $(PLATFORM_LIBS) \
> .........
>
> Switch library is compiled with same TEXT_BASE and other flags as that
> of u-boot.
>
> Second
> ======
> Theory: Build the network switch driver as a u-boot application, flash
> it on a free partition on the NOR and after u-boot has booted, it will
> somehow do the following to initialize the network switch.
>
> cp.b 0xfff90000 0x40000 0x5bfac
> go 0x00040418
>
> Practice: The above two commands worked to initialize the switch. I
> still need to understand how to run these command automatically after
> the u-boot has booted.
>
>
> Questions:
> 1.) Which design is recommended, first or the second? Second is easier
> for me to implement as I don't have to change the partition sizes but
> could easily be overlooking some obvious problems.
>   
It would help to know which type of Broadcom switch it is you're using.  
A lot of them have a SPI-based control plane, in which case you can set 
up a simple port configuration without an elaborate driver.

regards,
Ben