I am trying to upgrade my u-boot from 2008.10 to 2009.06. So I used the buildroot 2009.06 to build the tool chain for my mips32 board as well as u-boot. I also copied the previous u-boot initialization code to initialze timer, serial port, ram and etc from u-boot 2008.10 to 2009.06. My previous version of u-boot-2008.10 was working, but after porting it over to u-boot 2009.06, there is no output from console at all. I used bdi hardware debugger to debug it, and found that u-boot is stuck in file drivers/serial/ns16550.c function NS16550_putc. There is a while loop there : while ((com_port>lsr & LSR_THRE) == 0);
My understanding is the line here is to wait for the hardware register (LSR_THRE) to acknowledge the input character was received by the hardware.
But I don't have any clue how to fix this issue. I think I have initialized the serial port the same way as I did for u-boot 2008.10. Can some one give me some suggestions on what to check for?
Thanks.