Fwd: [PATCH] serial: implement riscv SBI console support

Fwd: [PATCH] serial: implement riscv SBI console support

[Marcelo Politzer]

Implement a console over legacy SBI (version 0.1.0). There is a tiny ringbuffer
to simplify checking for presence and reading characters as separate steps.

Signed-off-by: Marcelo Politzer <marcelo.politzer@cartesi.io>
---
 arch/riscv/cpu/core.c       | 13 ++++++++
 arch/riscv/lib/sbi.c        | 11 +++++++
 drivers/serial/Kconfig      |  8 +++++
 drivers/serial/Makefile     |  1 +
 drivers/serial/serial_sbi.c | 60 +++++++++++++++++++++++++++++++++++++
 5 files changed, 93 insertions(+)
 create mode 100644 drivers/serial/serial_sbi.c

diff --git a/arch/riscv/cpu/core.c b/arch/riscv/cpu/core.c
index 80730c05b..9226037f3 100644
--- a/arch/riscv/cpu/core.c
+++ b/arch/riscv/cpu/core.c
@@ -24,6 +24,7 @@
 #include <magicvar.h>
 #include <asm/system.h>
 #include <io.h>
+#include <asm/sbi.h>

 static int riscv_request_stack(void)
 {
@@ -33,6 +34,7 @@ static int riscv_request_stack(void)
 coredevice_initcall(riscv_request_stack);

 static struct device_d timer_dev;
+static struct device_d serial_sbi_dev;

 static s64 hartid;

@@ -75,6 +77,17 @@ static int riscv_probe(struct device_d *parent)
                        return ret;
        }

+       if (IS_ENABLED(CONFIG_SERIAL_SBI) && !serial_sbi_dev.parent) {
+               serial_sbi_dev.id = DEVICE_ID_SINGLE;
+               serial_sbi_dev.device_node = 0;
+               serial_sbi_dev.parent = parent;
+               dev_set_name(&serial_sbi_dev, "riscv-serial-sbi");
+
+               ret = platform_device_register(&serial_sbi_dev);
+               if (ret)
+                       return ret;
+       }
+
        hartid = riscv_hartid();
        if (hartid >= 0)
                globalvar_add_simple_uint64("hartid", &hartid, "%llu");
diff --git a/arch/riscv/lib/sbi.c b/arch/riscv/lib/sbi.c
index 45a04fb82..209069c98 100644
--- a/arch/riscv/lib/sbi.c
+++ b/arch/riscv/lib/sbi.c
@@ -64,3 +64,14 @@ static int sbi_init(void)

 }
 core_initcall(sbi_init);
+
+
+void sbi_console_putchar(int ch)
+{
+       sbi_ecall(SBI_EXT_0_1_CONSOLE_PUTCHAR, 0, ch, 0, 0, 0, 0, 0);
+}
+
+int sbi_console_getchar(void)
+{
+       return sbi_ecall(SBI_EXT_0_1_CONSOLE_GETCHAR, 0, 0, 0, 0, 0,
0, 0).error;
+}
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index b9750d177..5e30ea388 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -173,4 +173,12 @@ config SERIAL_SIFIVE
          contains a SiFive UART IP block.  This type of UART is present on
          SiFive FU540 SoCs, among others.

+config SERIAL_SBI
+       tristate "RISCV Serial support over SBI's HTIF"
+       depends on OFDEVICE
+       depends on RISCV_SBI
+       help
+         Select this option if you are building barebox for a RISCV platform
+         that implements a serial over SBI.
+
 endmenu
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 5120b1737..b1de436ed 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -24,3 +24,4 @@ obj-$(CONFIG_DRIVER_SERIAL_DIGIC)             +=
serial_digic.o
 obj-$(CONFIG_DRIVER_SERIAL_LPUART)             += serial_lpuart.o
 obj-$(CONFIG_VIRTIO_CONSOLE)                   += virtio_console.o
 obj-$(CONFIG_SERIAL_SIFIVE)                    += serial_sifive.o
+obj-$(CONFIG_SERIAL_SBI)                       += serial_sbi.o
diff --git a/drivers/serial/serial_sbi.c b/drivers/serial/serial_sbi.c
new file mode 100644
index 000000000..7217ce9cc
--- /dev/null
+++ b/drivers/serial/serial_sbi.c
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2021 Marcelo Politzer <marcelo.politzer@cartesi.io>
+ */
+
+#include <common.h>
+#include <driver.h>
+#include <malloc.h>
+#include <io.h>
+#include <of.h>
+#include <asm/sbi.h>
+
+struct sbi_serial_priv {
+       struct console_device cdev;
+       uint8_t b[2], head, tail;
+};
+
+static int sbi_serial_getc(struct console_device *cdev)
+{
+       struct sbi_serial_priv *priv = cdev->dev->priv;
+       if (priv->head == priv->tail)
+               return -1;
+       return priv->b[priv->head++ & 0x1];
+}
+
+static void sbi_serial_putc(struct console_device *cdev, const char ch)
+{
+       sbi_console_putchar(ch);
+}
+
+static int sbi_serial_tstc(struct console_device *cdev)
+{
+       struct sbi_serial_priv *priv = cdev->dev->priv;
+       int c = sbi_console_getchar();
+
+       if (c != -1)
+               priv->b[priv->tail++ & 0x1] = c;
+       return priv->head != priv->tail;
+}
+
+static int sbi_serial_probe(struct device_d *dev)
+{
+       struct sbi_serial_priv *priv;
+
+       priv = dev->priv = xzalloc(sizeof(*priv));
+       priv->cdev.dev    = dev;
+       priv->cdev.putc   = sbi_serial_putc;
+       priv->cdev.getc   = sbi_serial_getc;
+       priv->cdev.tstc   = sbi_serial_tstc;
+       priv->cdev.flush  = 0;
+       priv->cdev.setbrg = 0;
+
+       return console_register(&priv->cdev);
+}
+
+static struct driver_d serial_sbi_driver = {
+       .name   = "riscv-serial-sbi",
+       .probe  = sbi_serial_probe,
+};
+postcore_platform_driver(serial_sbi_driver);
--
2.32.0

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Re: Fwd: [PATCH] serial: implement riscv SBI console support

[Antony Pavlov]

On Fri, 24 Sep 2021 10:13:38 -0300
Marcelo Politzer <marcelo.politzer@cartesi.io> wrote:

Hi, Marcelo!


> Implement a console over legacy SBI (version 0.1.0). There is a tiny ringbuffer
> to simplify checking for presence and reading characters as separate steps.
> 
> Signed-off-by: Marcelo Politzer <marcelo.politzer@cartesi.io>
> ---
>  arch/riscv/cpu/core.c       | 13 ++++++++
>  arch/riscv/lib/sbi.c        | 11 +++++++
>  drivers/serial/Kconfig      |  8 +++++
>  drivers/serial/Makefile     |  1 +
>  drivers/serial/serial_sbi.c | 60 +++++++++++++++++++++++++++++++++++++
>  5 files changed, 93 insertions(+)
>  create mode 100644 drivers/serial/serial_sbi.c
> 
> diff --git a/arch/riscv/cpu/core.c b/arch/riscv/cpu/core.c
> index 80730c05b..9226037f3 100644
> --- a/arch/riscv/cpu/core.c
> +++ b/arch/riscv/cpu/core.c
> @@ -24,6 +24,7 @@
>  #include <magicvar.h>
>  #include <asm/system.h>
>  #include <io.h>
> +#include <asm/sbi.h>

There is no need to include <asm/sbi.h> here.

> 
>  static int riscv_request_stack(void)
>  {
> @@ -33,6 +34,7 @@ static int riscv_request_stack(void)
>  coredevice_initcall(riscv_request_stack);
> 
>  static struct device_d timer_dev;
> +static struct device_d serial_sbi_dev;
> 
>  static s64 hartid;
> 
> @@ -75,6 +77,17 @@ static int riscv_probe(struct device_d *parent)
>                         return ret;
>         }
> 
> +       if (IS_ENABLED(CONFIG_SERIAL_SBI) && !serial_sbi_dev.parent) {
> +               serial_sbi_dev.id = DEVICE_ID_SINGLE;
> +               serial_sbi_dev.device_node = 0;
> +               serial_sbi_dev.parent = parent;
> +               dev_set_name(&serial_sbi_dev, "riscv-serial-sbi");
> +
> +               ret = platform_device_register(&serial_sbi_dev);
> +               if (ret)
> +                       return ret;
> +       }
> +

Please, use tabs for indentation!


>         hartid = riscv_hartid();
>         if (hartid >= 0)
>                 globalvar_add_simple_uint64("hartid", &hartid, "%llu");
> diff --git a/arch/riscv/lib/sbi.c b/arch/riscv/lib/sbi.c
> index 45a04fb82..209069c98 100644
> --- a/arch/riscv/lib/sbi.c
> +++ b/arch/riscv/lib/sbi.c
> @@ -64,3 +64,14 @@ static int sbi_init(void)
> 
>  }
>  core_initcall(sbi_init);
> +
> +

No extra emptyline here.

> +void sbi_console_putchar(int ch)
> +{
> +       sbi_ecall(SBI_EXT_0_1_CONSOLE_PUTCHAR, 0, ch, 0, 0, 0, 0, 0);
> +}
> +
> +int sbi_console_getchar(void)
> +{
> +       return sbi_ecall(SBI_EXT_0_1_CONSOLE_GETCHAR, 0, 0, 0, 0, 0,
> 0, 0).error;
> +}
> diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
> index b9750d177..5e30ea388 100644
> --- a/drivers/serial/Kconfig
> +++ b/drivers/serial/Kconfig
> @@ -173,4 +173,12 @@ config SERIAL_SIFIVE
>           contains a SiFive UART IP block.  This type of UART is present on
>           SiFive FU540 SoCs, among others.
> 
> +config SERIAL_SBI
> +       tristate "RISCV Serial support over SBI's HTIF"
> +       depends on OFDEVICE
> +       depends on RISCV_SBI
> +       help
> +         Select this option if you are building barebox for a RISCV platform
> +         that implements a serial over SBI.
> +
>  endmenu
> diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
> index 5120b1737..b1de436ed 100644
> --- a/drivers/serial/Makefile
> +++ b/drivers/serial/Makefile
> @@ -24,3 +24,4 @@ obj-$(CONFIG_DRIVER_SERIAL_DIGIC)             +=
> serial_digic.o
>  obj-$(CONFIG_DRIVER_SERIAL_LPUART)             += serial_lpuart.o
>  obj-$(CONFIG_VIRTIO_CONSOLE)                   += virtio_console.o
>  obj-$(CONFIG_SERIAL_SIFIVE)                    += serial_sifive.o
> +obj-$(CONFIG_SERIAL_SBI)                       += serial_sbi.o
> diff --git a/drivers/serial/serial_sbi.c b/drivers/serial/serial_sbi.c
> new file mode 100644
> index 000000000..7217ce9cc
> --- /dev/null
> +++ b/drivers/serial/serial_sbi.c
> @@ -0,0 +1,60 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2021 Marcelo Politzer <marcelo.politzer@cartesi.io>
> + */
> +
> +#include <common.h>
> +#include <driver.h>
> +#include <malloc.h>
> +#include <io.h>
> +#include <of.h>

Please drop <io.h> and <of.h> inclusion here. These header files are unused.

> +#include <asm/sbi.h>
> +
> +struct sbi_serial_priv {
> +       struct console_device cdev;
> +       uint8_t b[2], head, tail;
> +};
> +
> +static int sbi_serial_getc(struct console_device *cdev)
> +{
> +       struct sbi_serial_priv *priv = cdev->dev->priv;
> +       if (priv->head == priv->tail)
> +               return -1;
> +       return priv->b[priv->head++ & 0x1];
> +}
> +
> +static void sbi_serial_putc(struct console_device *cdev, const char ch)
> +{
> +       sbi_console_putchar(ch);
> +}
> +
> +static int sbi_serial_tstc(struct console_device *cdev)
> +{
> +       struct sbi_serial_priv *priv = cdev->dev->priv;
> +       int c = sbi_console_getchar();
> +
> +       if (c != -1)
> +               priv->b[priv->tail++ & 0x1] = c;
> +       return priv->head != priv->tail;
> +}
> +
> +static int sbi_serial_probe(struct device_d *dev)
> +{
> +       struct sbi_serial_priv *priv;
> +
> +       priv = dev->priv = xzalloc(sizeof(*priv));
> +       priv->cdev.dev    = dev;
> +       priv->cdev.putc   = sbi_serial_putc;
> +       priv->cdev.getc   = sbi_serial_getc;
> +       priv->cdev.tstc   = sbi_serial_tstc;
> +       priv->cdev.flush  = 0;
> +       priv->cdev.setbrg = 0;
> +
> +       return console_register(&priv->cdev);
> +}
> +
> +static struct driver_d serial_sbi_driver = {
> +       .name   = "riscv-serial-sbi",
> +       .probe  = sbi_serial_probe,
> +};
> +postcore_platform_driver(serial_sbi_driver);
> --
> 2.32.0
> 
> _______________________________________________
> barebox mailing list
> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox


-- 
Best regards,
  Antony Pavlov

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Re: Fwd: [PATCH] serial: implement riscv SBI console support

[Marcelo Politzer]

Thank you for taking the time to review,

I've sent a v2 with your suggestions incorporated.

best,
Marcelo

On Sat, Sep 25, 2021 at 3:32 PM Antony Pavlov <antonynpavlov@gmail.com> wrote:
>
> On Fri, 24 Sep 2021 10:13:38 -0300
> Marcelo Politzer <marcelo.politzer@cartesi.io> wrote:
>
> Hi, Marcelo!
>
>
> > Implement a console over legacy SBI (version 0.1.0). There is a tiny ringbuffer
> > to simplify checking for presence and reading characters as separate steps.
> >
> > Signed-off-by: Marcelo Politzer <marcelo.politzer@cartesi.io>
> > ---
> >  arch/riscv/cpu/core.c       | 13 ++++++++
> >  arch/riscv/lib/sbi.c        | 11 +++++++
> >  drivers/serial/Kconfig      |  8 +++++
> >  drivers/serial/Makefile     |  1 +
> >  drivers/serial/serial_sbi.c | 60 +++++++++++++++++++++++++++++++++++++
> >  5 files changed, 93 insertions(+)
> >  create mode 100644 drivers/serial/serial_sbi.c
> >
> > diff --git a/arch/riscv/cpu/core.c b/arch/riscv/cpu/core.c
> > index 80730c05b..9226037f3 100644
> > --- a/arch/riscv/cpu/core.c
> > +++ b/arch/riscv/cpu/core.c
> > @@ -24,6 +24,7 @@
> >  #include <magicvar.h>
> >  #include <asm/system.h>
> >  #include <io.h>
> > +#include <asm/sbi.h>
>
> There is no need to include <asm/sbi.h> here.
>
> >
> >  static int riscv_request_stack(void)
> >  {
> > @@ -33,6 +34,7 @@ static int riscv_request_stack(void)
> >  coredevice_initcall(riscv_request_stack);
> >
> >  static struct device_d timer_dev;
> > +static struct device_d serial_sbi_dev;
> >
> >  static s64 hartid;
> >
> > @@ -75,6 +77,17 @@ static int riscv_probe(struct device_d *parent)
> >                         return ret;
> >         }
> >
> > +       if (IS_ENABLED(CONFIG_SERIAL_SBI) && !serial_sbi_dev.parent) {
> > +               serial_sbi_dev.id = DEVICE_ID_SINGLE;
> > +               serial_sbi_dev.device_node = 0;
> > +               serial_sbi_dev.parent = parent;
> > +               dev_set_name(&serial_sbi_dev, "riscv-serial-sbi");
> > +
> > +               ret = platform_device_register(&serial_sbi_dev);
> > +               if (ret)
> > +                       return ret;
> > +       }
> > +
>
> Please, use tabs for indentation!
>
>
> >         hartid = riscv_hartid();
> >         if (hartid >= 0)
> >                 globalvar_add_simple_uint64("hartid", &hartid, "%llu");
> > diff --git a/arch/riscv/lib/sbi.c b/arch/riscv/lib/sbi.c
> > index 45a04fb82..209069c98 100644
> > --- a/arch/riscv/lib/sbi.c
> > +++ b/arch/riscv/lib/sbi.c
> > @@ -64,3 +64,14 @@ static int sbi_init(void)
> >
> >  }
> >  core_initcall(sbi_init);
> > +
> > +
>
> No extra emptyline here.
>
> > +void sbi_console_putchar(int ch)
> > +{
> > +       sbi_ecall(SBI_EXT_0_1_CONSOLE_PUTCHAR, 0, ch, 0, 0, 0, 0, 0);
> > +}
> > +
> > +int sbi_console_getchar(void)
> > +{
> > +       return sbi_ecall(SBI_EXT_0_1_CONSOLE_GETCHAR, 0, 0, 0, 0, 0,
> > 0, 0).error;
> > +}
> > diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
> > index b9750d177..5e30ea388 100644
> > --- a/drivers/serial/Kconfig
> > +++ b/drivers/serial/Kconfig
> > @@ -173,4 +173,12 @@ config SERIAL_SIFIVE
> >           contains a SiFive UART IP block.  This type of UART is present on
> >           SiFive FU540 SoCs, among others.
> >
> > +config SERIAL_SBI
> > +       tristate "RISCV Serial support over SBI's HTIF"
> > +       depends on OFDEVICE
> > +       depends on RISCV_SBI
> > +       help
> > +         Select this option if you are building barebox for a RISCV platform
> > +         that implements a serial over SBI.
> > +
> >  endmenu
> > diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
> > index 5120b1737..b1de436ed 100644
> > --- a/drivers/serial/Makefile
> > +++ b/drivers/serial/Makefile
> > @@ -24,3 +24,4 @@ obj-$(CONFIG_DRIVER_SERIAL_DIGIC)             +=
> > serial_digic.o
> >  obj-$(CONFIG_DRIVER_SERIAL_LPUART)             += serial_lpuart.o
> >  obj-$(CONFIG_VIRTIO_CONSOLE)                   += virtio_console.o
> >  obj-$(CONFIG_SERIAL_SIFIVE)                    += serial_sifive.o
> > +obj-$(CONFIG_SERIAL_SBI)                       += serial_sbi.o
> > diff --git a/drivers/serial/serial_sbi.c b/drivers/serial/serial_sbi.c
> > new file mode 100644
> > index 000000000..7217ce9cc
> > --- /dev/null
> > +++ b/drivers/serial/serial_sbi.c
> > @@ -0,0 +1,60 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright (C) 2021 Marcelo Politzer <marcelo.politzer@cartesi.io>
> > + */
> > +
> > +#include <common.h>
> > +#include <driver.h>
> > +#include <malloc.h>
> > +#include <io.h>
> > +#include <of.h>
>
> Please drop <io.h> and <of.h> inclusion here. These header files are unused.
>
> > +#include <asm/sbi.h>
> > +
> > +struct sbi_serial_priv {
> > +       struct console_device cdev;
> > +       uint8_t b[2], head, tail;
> > +};
> > +
> > +static int sbi_serial_getc(struct console_device *cdev)
> > +{
> > +       struct sbi_serial_priv *priv = cdev->dev->priv;
> > +       if (priv->head == priv->tail)
> > +               return -1;
> > +       return priv->b[priv->head++ & 0x1];
> > +}
> > +
> > +static void sbi_serial_putc(struct console_device *cdev, const char ch)
> > +{
> > +       sbi_console_putchar(ch);
> > +}
> > +
> > +static int sbi_serial_tstc(struct console_device *cdev)
> > +{
> > +       struct sbi_serial_priv *priv = cdev->dev->priv;
> > +       int c = sbi_console_getchar();
> > +
> > +       if (c != -1)
> > +               priv->b[priv->tail++ & 0x1] = c;
> > +       return priv->head != priv->tail;
> > +}
> > +
> > +static int sbi_serial_probe(struct device_d *dev)
> > +{
> > +       struct sbi_serial_priv *priv;
> > +
> > +       priv = dev->priv = xzalloc(sizeof(*priv));
> > +       priv->cdev.dev    = dev;
> > +       priv->cdev.putc   = sbi_serial_putc;
> > +       priv->cdev.getc   = sbi_serial_getc;
> > +       priv->cdev.tstc   = sbi_serial_tstc;
> > +       priv->cdev.flush  = 0;
> > +       priv->cdev.setbrg = 0;
> > +
> > +       return console_register(&priv->cdev);
> > +}
> > +
> > +static struct driver_d serial_sbi_driver = {
> > +       .name   = "riscv-serial-sbi",
> > +       .probe  = sbi_serial_probe,
> > +};
> > +postcore_platform_driver(serial_sbi_driver);
> > --
> > 2.32.0
> >
> > _______________________________________________
> > barebox mailing list
> > barebox@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/barebox
>
>
> --
> Best regards,
>   Antony Pavlov

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