In message 00a401c4ef12$b9560a50$0bbca80a@kmyin you wrote:

My working target is the arm926ejs based platform. we want to port the

gdb-stub to the u-boot. therefore two console port should be used, one is

What for?

for host teminal program , another is for the host gdb debugger. right now the serial driver in our platform is polling based. Is there anybody kindly telling me how to initialize the two consoles or any material I can refer to and is it possible to achieve to port gdb-stub into the u-boot with such the polling based serial driver.

Please check existing code before reinventing the wheel. There is already support for kgdb in U-Boot, and there is BedBug, too. It is probably more useful to adapt/extend one of those for your purposes.

Best regards,

Wolfgang Denk