[PATCH 1/3] serial: Add RISC-V HTIF console driver

[Anup Patel]

On Tue, Jan 25, 2022 at 10:22 AM Bin Meng <bmeng.cn at gmail.com> wrote:
>
> On Sat, Jan 15, 2022 at 12:20 AM Anup Patel <apatel at ventanamicro.com> wrote:
> >
> > Quite a few RISC-V emulators and ISS (including Spike) have host
> > transfer interface (HTIF) based console. This patch adds HTIF
> > based console driver for RISC-V platforms which depends totally
> > on DT node for HTIF register base address.
> >
> > Signed-off-by: Anup Patel <apatel at ventanamicro.com>
> > Reviewed-by: Philipp Tomsich <philipp.tomsich at vrull.eu>
> > ---
> >  drivers/serial/Kconfig       |   8 ++
> >  drivers/serial/Makefile      |   1 +
> >  drivers/serial/serial_htif.c | 178 +++++++++++++++++++++++++++++++++++
> >  3 files changed, 187 insertions(+)
> >  create mode 100644 drivers/serial/serial_htif.c
> >
> > diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
> > index 6c8fdda9a0..345d1881f5 100644
> > --- a/drivers/serial/Kconfig
> > +++ b/drivers/serial/Kconfig
> > @@ -866,6 +866,14 @@ config PXA_SERIAL
> >           If you have a machine based on a Marvell XScale PXA2xx CPU you
> >           can enable its onboard serial ports by enabling this option.
> >
> > +config HTIF_CONSOLE
> > +       bool "RISC-V HTIF console support"
> > +       depends on DM_SERIAL && 64BIT
>
> Does this driver not work on 32-bit?

Only putc() works but getc() does not work on 32-bit. Same issue
is there with OpenSBI and BBL as well. That's why I have restricted
this driver to 64-bit only.

>
> > +       help
> > +         Select this to enable host transfer interface (HTIF) based serial
> > +         console. The HTIF device is quite common in RISC-V emulators and
> > +         RISC-V ISS so this driver allows using U-Boot on such platforms.
> > +
> >  config SIFIVE_SERIAL
> >         bool "SiFive UART support"
> >         depends on DM_SERIAL
>
> Regards,
> Bin

Regards,
Anup