Early debug UART not working on AM33XX SoC

[Felix Brack]

Hello Simon,

I am trying to get the current U-Boot master working on the PDU001
board. This involves the use of an early debug UART.

With commit 0dba4586 (arm: Init the debug UART) the early debug UART on
the AM33XX SoC doesn't work anymore.

By looking at the code involved I believe a call to
setup_clocks_for_console() implemented in clock_am33xx.c before the call
to debug_uart_init() is missing. This is also what happens prior to
commit 0dba4586 by a call to early_system_init() which in turn calls
setup_early_clocks() which then calls setup_clocks_for_console().

My quick and dirty fix consist of inserting a call in crt0.S to
setup_clocks_for_console() just before the call to debug_uart_init()
which was added in commit 0dba4586. I have guarded this call with
#if/#endif testing for CONFIG_AM33XX. The code sequence in crt0.S now
looks like this:

#if defined(CONFIG_DEBUG_UART) && CONFIG_IS_ENABLED(SERIAL)
  #if defined(CONFIG_AM33XX)
    bl setup_clocks_for_console
  #endif
    bl debug_uart_init
#endif

However, from what I understand the crt0.S is for _all_ ARM boards hence
it's probably a bad idea polluting it with such #if/#endif tests for
different SoCs. What do you think?

If my quick and dirty fix is not that dirty I would be happy to send a
patch which would also include the removal of the currently remaining
call to debug_uart_init() in am33xx/board.c

Please apologize my narrow view of the matter dealing only with AM33XX SoCs.

-- 
Felix