[U-Boot] DEBUG macro granularity

[Simon Glass]

Hi,

There is a great big DEBUG define which determines whether debug() is a
printf() or a nop. This is used by various modules to make them more verbose
which is helpful sometimes.

Some modules have their own finer control over this, for example USB_DEBUG
in common/usb.c. Also:

$ grep -rsl _PRINTF\( .
./board/mpl/pati/pati.c
./board/mpl/common/usb_uhci.c
./board/esd/common/xilinx_jtag/micro.c
./common/usb_kbd.c
./common/usb_ether.c
./common/usb_storage.c
./common/usb.c
./arch/sparc/cpu/leon3/usb_uhci.c
./issue5563011_1.diff
./drivers/bios_emulator/x86emu/decode.c
./drivers/bios_emulator/x86emu/ops.c
./drivers/bios_emulator/x86emu/ops2.c
./drivers/bios_emulator/include/x86emu/debug.h

Recently I enabled DEBUG and got rather a lot of output, enough that it took
hours to boot a kernel (every MMC block printed a nice message from the GPIO
driver). I understand that creating these local DEBUG macros is frowned
upon, but without this it tends to make the U-Boot-wide DEBUG setting so
verbose as to be useless. It also means that every potentially verbose
module needs an '#undef DEBUG' at the top, which means the global flag is
overridden.

Can I suggest perhaps a way of allowing some sort of granularity in the
design, rather than just relying on hacking in DEBUG in each file? What is
the recommended approach, please?

Regards,
Simon