risc-v: implement DBCN based debug console
Use the DBCN SBI extension to implement a debug console.
Make it the default for S-mode RISC-V.
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index a1e0899..8c54bc9 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -218,6 +218,7 @@
choice
prompt "Select which UART will provide the debug UART"
depends on DEBUG_UART
+ default DEBUG_SBI_CONSOLE if RISCV_SMODE
default DEBUG_UART_NS16550
config DEBUG_UART_ALTERA_JTAGUART
@@ -289,11 +290,13 @@
config DEBUG_SBI_CONSOLE
bool "SBI"
- depends on SBI_V01
+ depends on RISCV_SMODE
help
Select this to enable a debug console which calls back to SBI to
output to the console. This can be useful for early debugging of
U-Boot when running on top of SBI (Supervisor Binary Interface).
+ This implementation of the debug UART is not available while in
+ M-mode (e.g. during SPL).
config DEBUG_UART_S5P
bool "Samsung S5P"