uboot enable debug printing information

Enable debugging information in uboot

In the u-boot/include/common.h file

#define DEBUG //Add this macro#ifdef DEBUG#define _DEBUG 1#else#define _DEBUG 0#endif

Use uart's debug function

There is no printing when uboot starts, you can enable the debug function of the UART, especially in the DM model, this function is very useful.
Add the following configuration to the defconfig file in the corresponding board.

CONFIG_DEBUG_UART=yCONFIG_DEBUG_UART_ZYNQ=yCONFIG_DEBUG_UART_BASE=0xe0001000CONFIG_DEBUG_UART_CLOCK=100000000