The changes from commit 0dba45864b2a ("arm: Init the debug UART") prevent the early debug UART from being initialized correctly. By adding a new SoC specific early UART initialization function this patch provides a generic location to add the required code. This code has to be SoC and not board specific. For the am33xx SoCs the fix consist of configuring early clocks.
Signed-off-by: Felix Brack fb@ltec.ch ---
arch/arm/mach-omap2/am33xx/board.c | 7 +++++++ drivers/serial/Kconfig | 13 +++++++++++++ include/debug_uart.h | 15 +++++++++++++++ 3 files changed, 35 insertions(+)
diff --git a/arch/arm/mach-omap2/am33xx/board.c b/arch/arm/mach-omap2/am33xx/board.c index c44667668e..a7f0445b93 100644 --- a/arch/arm/mach-omap2/am33xx/board.c +++ b/arch/arm/mach-omap2/am33xx/board.c @@ -604,3 +604,10 @@ int arch_cpu_init_dm(void) #endif return 0; } + +#if IS_ENABLED(CONFIG_DEBUG_UART_SOC_INIT) +void soc_debug_uart_init(void) +{ + setup_early_clocks(); +} +#endif diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig index 345d1881f5..3da4064d35 100644 --- a/drivers/serial/Kconfig +++ b/drivers/serial/Kconfig @@ -490,6 +490,19 @@ config DEBUG_UART_SHIFT value. Use this value to specify the shift to use, where 0=byte registers, 2=32-bit word registers, etc.
+config DEBUG_UART_SOC_INIT + bool "Enable SoC-specific debug UART init" + depends on DEBUG_UART + help + Boards using the same SoC might require some common settings before + the debug UART can be used. The board specific board_debug_uart_init() + is not the right place for such common settings as they would apply + to a specific board only instead of all boards using the same SoC. + When this option is enabled, the SoC specific function + soc_debug_uart_init() will be called when debug_uart_init() is called. + You can put any code here that is needed to set up the UART ready for + use. + config DEBUG_UART_BOARD_INIT bool "Enable board-specific debug UART init" depends on DEBUG_UART diff --git a/include/debug_uart.h b/include/debug_uart.h index 714b369e6f..ebc84c44cd 100644 --- a/include/debug_uart.h +++ b/include/debug_uart.h @@ -42,6 +42,12 @@ * - Immediately afterwards, add DEBUG_UART_FUNCS to define the rest of the * functionality (printch(), etc.) * + * If your SoC needs additional init for the UART to work, enable + * CONFIG_DEBUG_UART_SOC_INIT and write a function called + * soc_debug_uart_init() to perform that init. When debug_uart_init() is + * called, the init will happen automatically. Board specific code does not + * go here, see board_debug_uart_init() below. + * * If your board needs additional init for the UART to work, enable * CONFIG_DEBUG_UART_BOARD_INIT and write a function called * board_debug_uart_init() to perform that init. When debug_uart_init() is @@ -61,6 +67,14 @@ */ void debug_uart_init(void);
+#ifdef CONFIG_DEBUG_UART_SOC_INIT +void soc_debug_uart_init(void); +#else +static inline void soc_debug_uart_init(void) +{ +} +#endif + #ifdef CONFIG_DEBUG_UART_BOARD_INIT void board_debug_uart_init(void); #else @@ -192,6 +206,7 @@ void printdec(unsigned int value); \ void debug_uart_init(void) \ { \ + soc_debug_uart_init(); \ board_debug_uart_init(); \ _debug_uart_init(); \ _DEBUG_UART_ANNOUNCE \