If proper U-Boot on Turris Omnia tries to print something on debug UART then CPU hangs. Reason is that debug UART in proper U-Boot for Turris Omnia has incorrect configuration of base register. Base register is different in SPL and also in different stages of proper U-Boot.
Fix all these issues. Introduce new arch_very_early_init() ARM function which will be called at very early stage prior initialization of debug UART. Move code which moves internal mvebu registers to this function. And split configuration of DEBUG_UART_BASE into SPL and proper U-Boot to allow setting different values which matches current HW status.
With all these changes, it is possible call "printf" function in Turris Omnia's board_early_init_f() function in both SPL and proper U-Boot.
Pali Rohár (5): arm: Add new config option ARCH_VERY_EARLY_INIT arm: mvebu: Move internal registers in arch_very_early_init() function serial: Add new config option SPL_DEBUG_UART_BASE serial: ns16550: Add support for SPL_DEBUG_UART_BASE arm: mvebu: turris_omnia: Fix DEBUG_UART_BASE
arch/arm/Kconfig | 6 ++++++ arch/arm/lib/crt0.S | 5 +++++ arch/arm/mach-mvebu/Kconfig | 1 + arch/arm/mach-mvebu/Makefile | 1 + arch/arm/mach-mvebu/cpu.c | 31 ------------------------------- arch/arm/mach-mvebu/lowlevel.S | 27 +++++++++++++++++++++++++++ configs/turris_omnia_defconfig | 3 ++- drivers/serial/Kconfig | 7 +++++++ drivers/serial/ns16550.c | 4 ++-- 9 files changed, 51 insertions(+), 34 deletions(-) create mode 100644 arch/arm/mach-mvebu/lowlevel.S