Hello Simon On 27.01.22 18:33, Simon Glass wrote: > 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. > I will check that. Maybe the board_debug_uart_init() is not the right place then as it is board specific. Probably better to have a AM33XX platform specific function.
Having said that there is still something I don't understand: commit 0dba4586 has added a call to debug_uart_init() in crt0.S but not removed any existing call to debug_uart_init(). Hence this function is called twice. Is this intentional (and if so, why ?) or are the remaining calls some sort of leftovers? >> 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 -- Regards, Felix
