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 <20231118033859.726692-4-apatel@ventanamicro.com> <8c0f4eba-1923-4686-b07b-1f3b78b298e9@sifive.com>
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From:   Anup Patel <apatel@ventanamicro.com>
Date:   Thu, 23 Nov 2023 16:13:29 +0530
Message-ID: <CAK9=C2U7gD2DC+zTGvSb+6uhmA=Y-nL2Mpn8tbp8R81g_6ruEA@mail.gmail.com>
Subject: Re: [PATCH v4 3/5] tty/serial: Add RISC-V SBI debug console based earlycon
To:     Samuel Holland <samuel.holland@sifive.com>
Cc:     Conor Dooley <conor@kernel.org>,
        Andrew Jones <ajones@ventanamicro.com>,
        linux-riscv@lists.infradead.org, linux-serial@vger.kernel.org,
        linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jirislaby@kernel.org>
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On Wed, Nov 22, 2023 at 4:11=E2=80=AFAM Samuel Holland
<samuel.holland@sifive.com> wrote:
>
> Hi Anup,
>
> On 2023-11-17 9:38 PM, 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 <apatel@ventanamicro.com>
> > Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
> > ---
> >  drivers/tty/serial/Kconfig              |  2 +-
> >  drivers/tty/serial/earlycon-riscv-sbi.c | 24 ++++++++++++++++++++----
> >  2 files changed, 21 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> > index 732c893c8d16..1f2594b8ab9d 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/seri=
al/earlycon-riscv-sbi.c
> > index 27afb0b74ea7..5351e1e31f45 100644
> > --- a/drivers/tty/serial/earlycon-riscv-sbi.c
> > +++ b/drivers/tty/serial/earlycon-riscv-sbi.c
> > @@ -15,17 +15,33 @@ static void sbi_putc(struct uart_port *port, unsign=
ed 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 =3D 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)
> > +{
> > +     sbi_debug_console_write(n, __pa(s));
>
> This only works for strings in the linear mapping or the kernel mapping (=
not
> vmalloc, which includes the stack). So I don't think we can use __pa() he=
re.

In which case, we need extend sbi_debug_console_write() to
do the va-to-pa conversion for both earlycon-riscv-sbi.c and
hvc_riscv_sbi.c

>
> > +}
> > +
> >  static int __init early_sbi_setup(struct earlycon_device *device,
> >                                 const char *opt)
> >  {
> > -     device->con->write =3D sbi_console_write;
> > -     return 0;
> > +     int ret =3D 0;
> > +
> > +     if (sbi_debug_console_available) {
> > +             device->con->write =3D sbi_dbcn_console_write;
> > +     } else {
> > +             if (IS_ENABLED(CONFIG_RISCV_SBI_V01))
>
> "else if", no need for the extra block/indentation.

Okay, I will update.

>
> Regards,
> Samuel
>
> > +                     device->con->write =3D sbi_0_1_console_write;
> > +             else
> > +                     ret =3D -ENODEV;
> > +     }
> > +
> > +     return ret;
> >  }
> >  EARLYCON_DECLARE(sbi, early_sbi_setup);
>

Regards,
Anup