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 <apa...@ventanamicro.com>
> ---
>  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 <ajo...@ventanamicro.com>

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