2023-10-12 05:16:55

by Anup Patel

Subject: [PATCH v2 6/8] tty/serial: Add RISC-V SBI debug console based earlycon

We extend the existing RISC-V SBI earlycon support to use the new
RISC-V SBI debug console extension.

Signed-off-by: Anup Patel <[email protected]>
---
drivers/tty/serial/Kconfig | 2 +-
drivers/tty/serial/earlycon-riscv-sbi.c | 32 +++++++++++++++++++++----
2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index bdc568a4ab66..cec46091a716 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -87,7 +87,7 @@ config SERIAL_EARLYCON_SEMIHOST

config SERIAL_EARLYCON_RISCV_SBI
bool "Early console using RISC-V SBI"
- depends on RISCV_SBI_V01
+ depends on RISCV_SBI
select SERIAL_CORE
select SERIAL_CORE_CONSOLE
select SERIAL_EARLYCON
diff --git a/drivers/tty/serial/earlycon-riscv-sbi.c b/drivers/tty/serial/earlycon-riscv-sbi.c
index 27afb0b74ea7..c21cdef254e7 100644
--- a/drivers/tty/serial/earlycon-riscv-sbi.c
+++ b/drivers/tty/serial/earlycon-riscv-sbi.c
@@ -15,17 +15,41 @@ static void sbi_putc(struct uart_port *port, unsigned char c)
sbi_console_putchar(c);
}

-static void sbi_console_write(struct console *con,
- const char *s, unsigned n)
+static void sbi_0_1_console_write(struct console *con,
+ const char *s, unsigned int n)
{
struct earlycon_device *dev = con->data;
uart_console_write(&dev->port, s, n, sbi_putc);
}

+static void sbi_dbcn_console_write(struct console *con,
+ const char *s, unsigned int n)
+{
+ phys_addr_t pa = __pa(s);
+
+ if (IS_ENABLED(CONFIG_32BIT))
+ sbi_ecall(SBI_EXT_DBCN, SBI_EXT_DBCN_CONSOLE_WRITE,
+ n, lower_32_bits(pa), upper_32_bits(pa), 0, 0, 0);
+ else
+ sbi_ecall(SBI_EXT_DBCN, SBI_EXT_DBCN_CONSOLE_WRITE,
+ n, pa, 0, 0, 0, 0);
+}
+
static int __init early_sbi_setup(struct earlycon_device *device,
const char *opt)
{
- device->con->write = sbi_console_write;
- return 0;
+ int ret = 0;
+
+ if ((sbi_spec_version >= sbi_mk_version(2, 0)) &&
+ (sbi_probe_extension(SBI_EXT_DBCN) > 0)) {
+ device->con->write = sbi_dbcn_console_write;
+ } else {
+ if (IS_ENABLED(CONFIG_RISCV_SBI_V01))
+ device->con->write = sbi_0_1_console_write;
+ else
+ ret = -ENODEV;
+ }
+
+ return ret;
}
EARLYCON_DECLARE(sbi, early_sbi_setup);
--
2.34.1

2023-10-19 08:28:00

by Andrew Jones

Subject: Re: [PATCH v2 6/8] tty/serial: Add RISC-V SBI debug console based earlycon

On Thu, Oct 12, 2023 at 10:45:07AM +0530, Anup Patel wrote:
> We extend the existing RISC-V SBI earlycon support to use the new
> RISC-V SBI debug console extension.
>
> Signed-off-by: Anup Patel <[email protected]>
> ---
> drivers/tty/serial/Kconfig | 2 +-
> drivers/tty/serial/earlycon-riscv-sbi.c | 32 +++++++++++++++++++++----
> 2 files changed, 29 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> index bdc568a4ab66..cec46091a716 100644
> --- a/drivers/tty/serial/Kconfig
> +++ b/drivers/tty/serial/Kconfig
> @@ -87,7 +87,7 @@ config SERIAL_EARLYCON_SEMIHOST
>
> config SERIAL_EARLYCON_RISCV_SBI
> bool "Early console using RISC-V SBI"
> - depends on RISCV_SBI_V01
> + depends on RISCV_SBI
> select SERIAL_CORE
> select SERIAL_CORE_CONSOLE
> select SERIAL_EARLYCON
> diff --git a/drivers/tty/serial/earlycon-riscv-sbi.c b/drivers/tty/serial/earlycon-riscv-sbi.c
> index 27afb0b74ea7..c21cdef254e7 100644
> --- a/drivers/tty/serial/earlycon-riscv-sbi.c
> +++ b/drivers/tty/serial/earlycon-riscv-sbi.c
> @@ -15,17 +15,41 @@ static void sbi_putc(struct uart_port *port, unsigned char c)
> sbi_console_putchar(c);
> }
>
> -static void sbi_console_write(struct console *con,
> - const char *s, unsigned n)
> +static void sbi_0_1_console_write(struct console *con,
> + const char *s, unsigned int n)
> {
> struct earlycon_device *dev = con->data;
> uart_console_write(&dev->port, s, n, sbi_putc);
> }
>
> +static void sbi_dbcn_console_write(struct console *con,
> + const char *s, unsigned int n)
> +{
> + phys_addr_t pa = __pa(s);
> +
> + if (IS_ENABLED(CONFIG_32BIT))
> + sbi_ecall(SBI_EXT_DBCN, SBI_EXT_DBCN_CONSOLE_WRITE,
> + n, lower_32_bits(pa), upper_32_bits(pa), 0, 0, 0);
> + else
> + sbi_ecall(SBI_EXT_DBCN, SBI_EXT_DBCN_CONSOLE_WRITE,
> + n, pa, 0, 0, 0, 0);
> +}
> +
> static int __init early_sbi_setup(struct earlycon_device *device,
> const char *opt)
> {
> - device->con->write = sbi_console_write;
> - return 0;
> + int ret = 0;
> +
> + if ((sbi_spec_version >= sbi_mk_version(2, 0)) &&
> + (sbi_probe_extension(SBI_EXT_DBCN) > 0)) {
> + device->con->write = sbi_dbcn_console_write;
> + } else {
> + if (IS_ENABLED(CONFIG_RISCV_SBI_V01))
> + device->con->write = sbi_0_1_console_write;
> + else
> + ret = -ENODEV;
> + }
> +
> + return ret;
> }
> EARLYCON_DECLARE(sbi, early_sbi_setup);
> --
> 2.34.1
>

Reviewed-by: Andrew Jones <[email protected]>