[PATCH v2 0/2] risc-v: implement DBCN based debug console
Currently we only offer an SBI based debug UART for SBI v0.1. With OpenSBI 1.3 the Debug Console Extension (DBCN) has become available. This allows us to implement a debug UART in a device independent manor.
v2: In the driver check that we are in S-mode.
Heinrich Schuchardt (2): risc-v: implement DBCN write byte risc-v: implement DBCN based debug console
arch/riscv/include/asm/sbi.h | 1 + arch/riscv/lib/sbi.c | 16 ++++++++++++++++ drivers/serial/Kconfig | 5 ++++- drivers/serial/serial_sbi.c | 20 ++++++++++++++++++++ 4 files changed, 41 insertions(+), 1 deletion(-)
The DBCN extension provides a Console Write Byte call. Implement function sbi_dbcn_write_byte to invoke it.
Signed-off-by: Heinrich Schuchardt heinrich.schuchardt@canonical.com Reviewed-by: Leo Yu-Chi Liang ycliang@andestech.com --- v2: no change --- arch/riscv/include/asm/sbi.h | 1 + arch/riscv/lib/sbi.c | 16 ++++++++++++++++ 2 files changed, 17 insertions(+)
diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h index 009a26885c..bf4c9af622 100644 --- a/arch/riscv/include/asm/sbi.h +++ b/arch/riscv/include/asm/sbi.h @@ -170,5 +170,6 @@ int sbi_get_mvendorid(long *mvendorid); int sbi_get_marchid(long *marchid); int sbi_get_mimpid(long *mimpid); void sbi_srst_reset(unsigned long type, unsigned long reason); +int sbi_dbcn_write_byte(unsigned char ch);
#endif diff --git a/arch/riscv/lib/sbi.c b/arch/riscv/lib/sbi.c index 8724e3a460..55a3bc3b5c 100644 --- a/arch/riscv/lib/sbi.c +++ b/arch/riscv/lib/sbi.c @@ -204,6 +204,22 @@ void sbi_srst_reset(unsigned long type, unsigned long reason) 0, 0, 0, 0); }
+/** + * sbi_dbcn_write_byte() - write byte to debug console + * + * @ch: byte to be written + * Return: SBI error code (SBI_SUCCESS = 0 on success) + */ +int sbi_dbcn_write_byte(unsigned char ch) +{ + struct sbiret ret; + + ret = sbi_ecall(SBI_EXT_DBCN, + SBI_EXT_DBCN_CONSOLE_WRITE_BYTE, + ch, 0, 0, 0, 0, 0); + return ret.error; +} + #ifdef CONFIG_SBI_V01
/**
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 --- v2: check that we are in S-mode --- drivers/serial/Kconfig | 5 ++++- drivers/serial/serial_sbi.c | 20 ++++++++++++++++++++ 2 files changed, 24 insertions(+), 1 deletion(-)
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig index 7ca42df6a7..fb108f0189 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 @@ -289,11 +290,13 @@ 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 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" diff --git a/drivers/serial/serial_sbi.c b/drivers/serial/serial_sbi.c index b9f35ed36e..a51a96c1ef 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 +15,22 @@ 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) +{ + if (CONFIG_IS_ENABLED(RISCV_SMODE)) + sbi_dbcn_available = sbi_probe_extension(SBI_EXT_DBCN); +} + +static inline void _debug_uart_putc(int ch) +{ + if (CONFIG_IS_ENABLED(RISCV_SMODE) && sbi_dbcn_available) + sbi_dbcn_write_byte(ch); +} + +#endif + DEBUG_UART_FUNCS
On Mon, Sep 04, 2023 at 01:24:04PM +0200, Heinrich Schuchardt wrote:
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
v2: check that we are in S-mode
drivers/serial/Kconfig | 5 ++++- drivers/serial/serial_sbi.c | 20 ++++++++++++++++++++ 2 files changed, 24 insertions(+), 1 deletion(-)
Reviewed-by: Leo Yu-Chi Liang ycliang@andestech.com
Hi,
-----Original Message----- From: Heinrich Schuchardt heinrich.schuchardt@canonical.com Sent: Monday, September 4, 2023 8:24 PM To: Rick Chen rick@andestech.com; Leo ycliang@andestech.com Cc: Bin Meng bmeng.cn@gmail.com; Anup Patel apatel@ventanamicro.com; Chanho Park chanho61.park@samsung.com; u-boot@lists.denx.de; Heinrich Schuchardt heinrich.schuchardt@canonical.com Subject: [PATCH v2 0/2] risc-v: implement DBCN based debug console
Currently we only offer an SBI based debug UART for SBI v0.1. With OpenSBI 1.3 the Debug Console Extension (DBCN) has become available. This allows us to implement a debug UART in a device independent manor.
v2: In the driver check that we are in S-mode.
Thanks for the update. I've tested both patches on my VisionFive2 board.
Reviewed-by: Chanho Park chanho61.park@samsung.com Tested-by: Chanho Park chanho61.park@samsung.com
Best Regards, Chanho Park
participants (3)
-
Chanho Park -
Heinrich Schuchardt -
Leo Liang