[U-Boot] u-boot in debug mode P2020

Hello I try to run u-boot-2009.11 on the chip P2020 from SDcard. When i run u-boot i see in the terminal:

CPU0: P2020E, Version: 2.1, (0x80ea0021) Core: E500, Version: 5.1, (0x80211051) Clock Configuration: CPU0:1200 MHz, CPU1:1200 MHz, CCB:600 MHz, DDR:300 MHz (600 MT/s data rate) (Asynchronous), LBC:37.500 MHz L1: D-cache 32 kB enabled I-cache 32 kB enabled I2C: ready SPI: ready DRAM: 1 GB

Failed reading I2C Chip 0x18 on bus 1

And u-boot get stuck. I would like to enable the output to the console debug message. But i can't find how to enable that function. How can i enable the debug output ?

Thanks