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

[Jatin Sharma]

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.

2.) If the first design is recommended, I would need to resolve the
u-boot-not-booting issue when the binary is compiled with switch
driver. Any suggestions where to look?

Thanks,
Jatin