Hi Felix, On Thu, 27 Jan 2022 at 09:27, Felix Brack <f...@ltec.ch> wrote: > > Hello Simon, > > On 27.01.22 16:05, Simon Glass wrote: > > Hi Felix, > > > > On Wed, 26 Jan 2022 at 07:02, Felix Brack <f...@ltec.ch> wrote: > >> > >> 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. > > > > Are you able to put that call into board_debug_uart_init() and enable > > CONFIG_DEBUG_UART_BOARD_INIT ? > > > Sure I can but there two drawbacks: > 1. this fixes the problem only for my board, others might remain broken
I suggest you make the function common to all boards that need it. > 2. the now redundant call to setup_early_clocks() in am33xx/board.c > remains (at least it does not seem to hurt ;-)) Yes, it is possible to use flags to avoid that, but might not be worth it. > > I will prepare a patch with a modified board_debug_uart_init() for the > PDU001 board then. > > -- > Many thanks for your help and kind regards, Felix > Regards, Simon
