[PATCH 2/2] risc-v: implement DBCN based debug console
Heinrich Schuchardt
heinrich.schuchardt at canonical.com
Sat Aug 19 15:12:50 CEST 2023
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 at canonical.com>
---
drivers/serial/Kconfig | 3 ++-
drivers/serial/serial_sbi.c | 19 +++++++++++++++++++
2 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index a1e089962a..8421c5c047 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -218,6 +218,7 @@ config DEBUG_UART
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
@@ -289,7 +290,7 @@ config DEBUG_EFI_CONSOLE
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
diff --git a/drivers/serial/serial_sbi.c b/drivers/serial/serial_sbi.c
index b9f35ed36e..093c7309d3 100644
--- a/drivers/serial/serial_sbi.c
+++ b/drivers/serial/serial_sbi.c
@@ -3,6 +3,8 @@
#include <debug_uart.h>
#include <asm/sbi.h>
+#ifdef CONFIG_SBI_V01
+
static inline void _debug_uart_init(void)
{
}
@@ -13,4 +15,21 @@ static inline void _debug_uart_putc(int c)
sbi_console_putchar(c);
}
+#else
+
+static int sbi_dbcn_available;
+
+static inline void _debug_uart_init(void)
+{
+ sbi_dbcn_available = sbi_probe_extension(SBI_EXT_DBCN);
+}
+
+static inline void _debug_uart_putc(int ch)
+{
+ if (sbi_dbcn_available)
+ sbi_dbcn_write_byte(ch);
+}
+
+#endif
+
DEBUG_UART_FUNCS
--
2.40.1
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