Most litex boards using RISC-V soft cores us the sbi earlycon, however
this is not available for non RISC-V litex SoC. This patch enables
earlycon for liteuart which is available on all Litex SoC's making
support for earycon debugging more widely available.
Signed-off-by: Stafford Horne <[email protected]>
Cc: Florent Kermarrec <[email protected]>
Cc: Mateusz Holenko <[email protected]>
Cc: Joel Stanley <[email protected]>
Cc: Gabriel L. Somlo <[email protected]>
---
.../admin-guide/kernel-parameters.txt | 5 +++
drivers/tty/serial/Kconfig | 1 +
drivers/tty/serial/liteuart.c | 31 +++++++++++++++++++
3 files changed, 37 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 04545725f187..2d4a43af8de2 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1084,6 +1084,11 @@
the driver will use only 32-bit accessors to read/write
the device registers.
+ liteuart,<addr>
+ Start an early console on a litex serial port at the
+ specified address. The serial port must already be
+ setup and configured. Options are not yet supported.
+
meson,<addr>
Start an early, polled-mode console on a meson serial
port at the specified address. The serial port must
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 0c4cd4a348f4..9ceffe6ab6fd 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1531,6 +1531,7 @@ config SERIAL_LITEUART
depends on OF || COMPILE_TEST
depends on LITEX
select SERIAL_CORE
+ select SERIAL_EARLYCON
help
This driver is for the FPGA-based LiteUART serial controller from LiteX
SoC builder.
diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.c
index 64842f3539e1..38c472487e68 100644
--- a/drivers/tty/serial/liteuart.c
+++ b/drivers/tty/serial/liteuart.c
@@ -372,6 +372,37 @@ static int __init liteuart_console_init(void)
console_initcall(liteuart_console_init);
#endif /* CONFIG_SERIAL_LITEUART_CONSOLE */
+#ifdef CONFIG_SERIAL_EARLYCON
+static void early_liteuart_putc(struct uart_port *port, int c)
+{
+ while (litex_read8(port->membase + OFF_TXFULL))
+ cpu_relax();
+
+ litex_write8(port->membase + OFF_RXTX, c);
+}
+
+static void early_liteuart_write(struct console *console, const char *s,
+ unsigned int count)
+{
+ struct earlycon_device *device = console->data;
+ struct uart_port *port = &device->port;
+
+ uart_console_write(port, s, count, early_liteuart_putc);
+}
+
+static int __init early_liteuart_setup(struct earlycon_device *device,
+ const char *options)
+{
+ if (!device->port.membase)
+ return -ENODEV;
+
+ device->con->write = early_liteuart_write;
+ return 0;
+}
+
+OF_EARLYCON_DECLARE(liteuart, "litex,liteuart", early_liteuart_setup);
+#endif /* CONFIG_SERIAL_EARLYCON */
+
static int __init liteuart_init(void)
{
int res;
--
2.31.1
On Sat, May 15, 2021 at 05:45:18PM +0900, Stafford Horne wrote:
> Most litex boards using RISC-V soft cores us the sbi earlycon, however
> this is not available for non RISC-V litex SoC. This patch enables
> earlycon for liteuart which is available on all Litex SoC's making
> support for earycon debugging more widely available.
>
> Signed-off-by: Stafford Horne <[email protected]>
> Cc: Florent Kermarrec <[email protected]>
> Cc: Mateusz Holenko <[email protected]>
> Cc: Joel Stanley <[email protected]>
> Cc: Gabriel L. Somlo <[email protected]>
> ---
> .../admin-guide/kernel-parameters.txt | 5 +++
> drivers/tty/serial/Kconfig | 1 +
> drivers/tty/serial/liteuart.c | 31 +++++++++++++++++++
> 3 files changed, 37 insertions(+)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 04545725f187..2d4a43af8de2 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1084,6 +1084,11 @@
> the driver will use only 32-bit accessors to read/write
> the device registers.
>
> + liteuart,<addr>
> + Start an early console on a litex serial port at the
> + specified address. The serial port must already be
> + setup and configured. Options are not yet supported.
> +
> meson,<addr>
> Start an early, polled-mode console on a meson serial
> port at the specified address. The serial port must
> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> index 0c4cd4a348f4..9ceffe6ab6fd 100644
> --- a/drivers/tty/serial/Kconfig
> +++ b/drivers/tty/serial/Kconfig
> @@ -1531,6 +1531,7 @@ config SERIAL_LITEUART
> depends on OF || COMPILE_TEST
> depends on LITEX
> select SERIAL_CORE
> + select SERIAL_EARLYCON
> help
> This driver is for the FPGA-based LiteUART serial controller from LiteX
> SoC builder.
> diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.c
> index 64842f3539e1..38c472487e68 100644
> --- a/drivers/tty/serial/liteuart.c
> +++ b/drivers/tty/serial/liteuart.c
> @@ -372,6 +372,37 @@ static int __init liteuart_console_init(void)
> console_initcall(liteuart_console_init);
> #endif /* CONFIG_SERIAL_LITEUART_CONSOLE */
>
> +#ifdef CONFIG_SERIAL_EARLYCON
> +static void early_liteuart_putc(struct uart_port *port, int c)
> +{
> + while (litex_read8(port->membase + OFF_TXFULL))
> + cpu_relax();
> +
> + litex_write8(port->membase + OFF_RXTX, c);
> +}
> +
> +static void early_liteuart_write(struct console *console, const char *s,
> + unsigned int count)
> +{
> + struct earlycon_device *device = console->data;
> + struct uart_port *port = &device->port;
> +
> + uart_console_write(port, s, count, early_liteuart_putc);
> +}
> +
> +static int __init early_liteuart_setup(struct earlycon_device *device,
> + const char *options)
> +{
> + if (!device->port.membase)
> + return -ENODEV;
> +
> + device->con->write = early_liteuart_write;
> + return 0;
> +}
> +
> +OF_EARLYCON_DECLARE(liteuart, "litex,liteuart", early_liteuart_setup);
> +#endif /* CONFIG_SERIAL_EARLYCON */
> +
> static int __init liteuart_init(void)
> {
> int res;
> --
> 2.31.1
FWIW:
Reviewed-and-tested-by: Gabriel Somlo <[email protected]>
Thanks,
--Gabriel
I pulled the trigger a bit early, the subject needs a bit better/consistent
formatting. It should be:
serial: liteuart: Add support for earlycon
On Sat, May 15, 2021 at 05:45:18PM +0900, Stafford Horne wrote:
> Most litex boards using RISC-V soft cores us the sbi earlycon, however
> this is not available for non RISC-V litex SoC. This patch enables
> earlycon for liteuart which is available on all Litex SoC's making
> support for earycon debugging more widely available.
>
> Signed-off-by: Stafford Horne <[email protected]>
> Cc: Florent Kermarrec <[email protected]>
> Cc: Mateusz Holenko <[email protected]>
> Cc: Joel Stanley <[email protected]>
> Cc: Gabriel L. Somlo <[email protected]>
> ---
> .../admin-guide/kernel-parameters.txt | 5 +++
> drivers/tty/serial/Kconfig | 1 +
> drivers/tty/serial/liteuart.c | 31 +++++++++++++++++++
> 3 files changed, 37 insertions(+)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 04545725f187..2d4a43af8de2 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1084,6 +1084,11 @@
> the driver will use only 32-bit accessors to read/write
> the device registers.
>
> + liteuart,<addr>
> + Start an early console on a litex serial port at the
> + specified address. The serial port must already be
> + setup and configured. Options are not yet supported.
> +
> meson,<addr>
> Start an early, polled-mode console on a meson serial
> port at the specified address. The serial port must
> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> index 0c4cd4a348f4..9ceffe6ab6fd 100644
> --- a/drivers/tty/serial/Kconfig
> +++ b/drivers/tty/serial/Kconfig
> @@ -1531,6 +1531,7 @@ config SERIAL_LITEUART
> depends on OF || COMPILE_TEST
> depends on LITEX
> select SERIAL_CORE
> + select SERIAL_EARLYCON
> help
> This driver is for the FPGA-based LiteUART serial controller from LiteX
> SoC builder.
> diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.c
> index 64842f3539e1..38c472487e68 100644
> --- a/drivers/tty/serial/liteuart.c
> +++ b/drivers/tty/serial/liteuart.c
> @@ -372,6 +372,37 @@ static int __init liteuart_console_init(void)
> console_initcall(liteuart_console_init);
> #endif /* CONFIG_SERIAL_LITEUART_CONSOLE */
>
> +#ifdef CONFIG_SERIAL_EARLYCON
> +static void early_liteuart_putc(struct uart_port *port, int c)
> +{
> + while (litex_read8(port->membase + OFF_TXFULL))
> + cpu_relax();
> +
> + litex_write8(port->membase + OFF_RXTX, c);
> +}
> +
> +static void early_liteuart_write(struct console *console, const char *s,
> + unsigned int count)
> +{
> + struct earlycon_device *device = console->data;
> + struct uart_port *port = &device->port;
> +
> + uart_console_write(port, s, count, early_liteuart_putc);
> +}
> +
> +static int __init early_liteuart_setup(struct earlycon_device *device,
> + const char *options)
> +{
> + if (!device->port.membase)
> + return -ENODEV;
> +
> + device->con->write = early_liteuart_write;
> + return 0;
> +}
> +
> +OF_EARLYCON_DECLARE(liteuart, "litex,liteuart", early_liteuart_setup);
> +#endif /* CONFIG_SERIAL_EARLYCON */
> +
> static int __init liteuart_init(void)
> {
> int res;
> --
> 2.31.1
>
On 15. 05. 21, 10:45, Stafford Horne wrote:
> Most litex boards using RISC-V soft cores us the sbi earlycon, however
> this is not available for non RISC-V litex SoC. This patch enables
> earlycon for liteuart which is available on all Litex SoC's making
> support for earycon debugging more widely available.
>
> Signed-off-by: Stafford Horne <[email protected]>
> Cc: Florent Kermarrec <[email protected]>
> Cc: Mateusz Holenko <[email protected]>
> Cc: Joel Stanley <[email protected]>
> Cc: Gabriel L. Somlo <[email protected]>
> ---
> .../admin-guide/kernel-parameters.txt | 5 +++
> drivers/tty/serial/Kconfig | 1 +
> drivers/tty/serial/liteuart.c | 31 +++++++++++++++++++
> 3 files changed, 37 insertions(+)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 04545725f187..2d4a43af8de2 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1084,6 +1084,11 @@
> the driver will use only 32-bit accessors to read/write
> the device registers.
>
> + liteuart,<addr>
> + Start an early console on a litex serial port at the
> + specified address. The serial port must already be
> + setup and configured. Options are not yet supported.
> +
> meson,<addr>
> Start an early, polled-mode console on a meson serial
> port at the specified address. The serial port must
> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> index 0c4cd4a348f4..9ceffe6ab6fd 100644
> --- a/drivers/tty/serial/Kconfig
> +++ b/drivers/tty/serial/Kconfig
> @@ -1531,6 +1531,7 @@ config SERIAL_LITEUART
> depends on OF || COMPILE_TEST
> depends on LITEX
> select SERIAL_CORE
> + select SERIAL_EARLYCON
> help
> This driver is for the FPGA-based LiteUART serial controller from LiteX
> SoC builder.
> diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.c
> index 64842f3539e1..38c472487e68 100644
> --- a/drivers/tty/serial/liteuart.c
> +++ b/drivers/tty/serial/liteuart.c
> @@ -372,6 +372,37 @@ static int __init liteuart_console_init(void)
> console_initcall(liteuart_console_init);
> #endif /* CONFIG_SERIAL_LITEUART_CONSOLE */
>
> +#ifdef CONFIG_SERIAL_EARLYCON
> +static void early_liteuart_putc(struct uart_port *port, int c)
> +{
> + while (litex_read8(port->membase + OFF_TXFULL))
> + cpu_relax();
> +
> + litex_write8(port->membase + OFF_RXTX, c);
Hi,
am I missing something or this doesn't differ to liteuart_putchar?
> +}
> +
> +static void early_liteuart_write(struct console *console, const char *s,
> + unsigned int count)
> +{
> + struct earlycon_device *device = console->data;
> + struct uart_port *port = &device->port;
> +
> + uart_console_write(port, s, count, early_liteuart_putc);
> +}
> +
> +static int __init early_liteuart_setup(struct earlycon_device *device,
> + const char *options)
> +{
> + if (!device->port.membase)
> + return -ENODEV;
> +
> + device->con->write = early_liteuart_write;
> + return 0;
> +}
> +
> +OF_EARLYCON_DECLARE(liteuart, "litex,liteuart", early_liteuart_setup);
> +#endif /* CONFIG_SERIAL_EARLYCON */
> +
> static int __init liteuart_init(void)
> {
> int res;
>
--
js
suse labs
On Mon, May 17, 2021 at 10:16:43AM +0200, Jiri Slaby wrote:
> On 15. 05. 21, 10:45, Stafford Horne wrote:
> > Most litex boards using RISC-V soft cores us the sbi earlycon, however
> > this is not available for non RISC-V litex SoC. This patch enables
> > earlycon for liteuart which is available on all Litex SoC's making
> > support for earycon debugging more widely available.
> >
> > Signed-off-by: Stafford Horne <[email protected]>
> > Cc: Florent Kermarrec <[email protected]>
> > Cc: Mateusz Holenko <[email protected]>
> > Cc: Joel Stanley <[email protected]>
> > Cc: Gabriel L. Somlo <[email protected]>
> > ---
> > .../admin-guide/kernel-parameters.txt | 5 +++
> > drivers/tty/serial/Kconfig | 1 +
> > drivers/tty/serial/liteuart.c | 31 +++++++++++++++++++
> > 3 files changed, 37 insertions(+)
> >
> > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > index 04545725f187..2d4a43af8de2 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -1084,6 +1084,11 @@
> > the driver will use only 32-bit accessors to read/write
> > the device registers.
> > + liteuart,<addr>
> > + Start an early console on a litex serial port at the
> > + specified address. The serial port must already be
> > + setup and configured. Options are not yet supported.
> > +
> > meson,<addr>
> > Start an early, polled-mode console on a meson serial
> > port at the specified address. The serial port must
> > diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> > index 0c4cd4a348f4..9ceffe6ab6fd 100644
> > --- a/drivers/tty/serial/Kconfig
> > +++ b/drivers/tty/serial/Kconfig
> > @@ -1531,6 +1531,7 @@ config SERIAL_LITEUART
> > depends on OF || COMPILE_TEST
> > depends on LITEX
> > select SERIAL_CORE
> > + select SERIAL_EARLYCON
> > help
> > This driver is for the FPGA-based LiteUART serial controller from LiteX
> > SoC builder.
> > diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.c
> > index 64842f3539e1..38c472487e68 100644
> > --- a/drivers/tty/serial/liteuart.c
> > +++ b/drivers/tty/serial/liteuart.c
> > @@ -372,6 +372,37 @@ static int __init liteuart_console_init(void)
> > console_initcall(liteuart_console_init);
> > #endif /* CONFIG_SERIAL_LITEUART_CONSOLE */
> > +#ifdef CONFIG_SERIAL_EARLYCON
> > +static void early_liteuart_putc(struct uart_port *port, int c)
> > +{
> > + while (litex_read8(port->membase + OFF_TXFULL))
> > + cpu_relax();
> > +
> > + litex_write8(port->membase + OFF_RXTX, c);
>
> Hi,
>
> am I missing something or this doesn't differ to liteuart_putchar?
Hi, No you are right, I missed that thanks for catching it.
I should be able to remove this function and use putchar below.
-Stafford
> > +}
> > +
> > +static void early_liteuart_write(struct console *console, const char *s,
> > + unsigned int count)
> > +{
> > + struct earlycon_device *device = console->data;
> > + struct uart_port *port = &device->port;
> > +
> > + uart_console_write(port, s, count, early_liteuart_putc);
> > +}
> > +
> > +static int __init early_liteuart_setup(struct earlycon_device *device,
> > + const char *options)
> > +{
> > + if (!device->port.membase)
> > + return -ENODEV;
> > +
> > + device->con->write = early_liteuart_write;
> > + return 0;
> > +}
> > +
> > +OF_EARLYCON_DECLARE(liteuart, "litex,liteuart", early_liteuart_setup);
> > +#endif /* CONFIG_SERIAL_EARLYCON */
> > +
> > static int __init liteuart_init(void)
> > {
> > int res;
> >
>
>
> --
> js
> suse labs
On 17. 05. 21, 10:23, Stafford Horne wrote:
> On Mon, May 17, 2021 at 10:16:43AM +0200, Jiri Slaby wrote:
>> On 15. 05. 21, 10:45, Stafford Horne wrote:
>>> Most litex boards using RISC-V soft cores us the sbi earlycon, however
>>> this is not available for non RISC-V litex SoC. This patch enables
>>> earlycon for liteuart which is available on all Litex SoC's making
>>> support for earycon debugging more widely available.
>>>
>>> Signed-off-by: Stafford Horne <[email protected]>
>>> Cc: Florent Kermarrec <[email protected]>
>>> Cc: Mateusz Holenko <[email protected]>
>>> Cc: Joel Stanley <[email protected]>
>>> Cc: Gabriel L. Somlo <[email protected]>
>>> ---
>>> .../admin-guide/kernel-parameters.txt | 5 +++
>>> drivers/tty/serial/Kconfig | 1 +
>>> drivers/tty/serial/liteuart.c | 31 +++++++++++++++++++
>>> 3 files changed, 37 insertions(+)
>>>
>>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>>> index 04545725f187..2d4a43af8de2 100644
>>> --- a/Documentation/admin-guide/kernel-parameters.txt
>>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>>> @@ -1084,6 +1084,11 @@
>>> the driver will use only 32-bit accessors to read/write
>>> the device registers.
>>> + liteuart,<addr>
>>> + Start an early console on a litex serial port at the
>>> + specified address. The serial port must already be
>>> + setup and configured. Options are not yet supported.
>>> +
>>> meson,<addr>
>>> Start an early, polled-mode console on a meson serial
>>> port at the specified address. The serial port must
>>> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
>>> index 0c4cd4a348f4..9ceffe6ab6fd 100644
>>> --- a/drivers/tty/serial/Kconfig
>>> +++ b/drivers/tty/serial/Kconfig
>>> @@ -1531,6 +1531,7 @@ config SERIAL_LITEUART
>>> depends on OF || COMPILE_TEST
>>> depends on LITEX
>>> select SERIAL_CORE
>>> + select SERIAL_EARLYCON
>>> help
>>> This driver is for the FPGA-based LiteUART serial controller from LiteX
>>> SoC builder.
>>> diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.c
>>> index 64842f3539e1..38c472487e68 100644
>>> --- a/drivers/tty/serial/liteuart.c
>>> +++ b/drivers/tty/serial/liteuart.c
>>> @@ -372,6 +372,37 @@ static int __init liteuart_console_init(void)
>>> console_initcall(liteuart_console_init);
>>> #endif /* CONFIG_SERIAL_LITEUART_CONSOLE */
>>> +#ifdef CONFIG_SERIAL_EARLYCON
>>> +static void early_liteuart_putc(struct uart_port *port, int c)
>>> +{
>>> + while (litex_read8(port->membase + OFF_TXFULL))
>>> + cpu_relax();
>>> +
>>> + litex_write8(port->membase + OFF_RXTX, c);
>>
>> Hi,
>>
>> am I missing something or this doesn't differ to liteuart_putchar?
>
> Hi, No you are right, I missed that thanks for catching it.
>
> I should be able to remove this function and use putchar below.
OK.
I've just noticed you add an ifdef CONFIG_SERIAL_EARLYCON here, but you
select SERIAL_EARLYCON in Kconfig above. So the ifdef is sort of
pointless? (Or you shouldn't select SERIAL_EARLYCON.)
thanks,
--
js
suse labs
On Mon, May 17, 2021 at 10:25:46AM +0200, Jiri Slaby wrote:
> On 17. 05. 21, 10:23, Stafford Horne wrote:
> > On Mon, May 17, 2021 at 10:16:43AM +0200, Jiri Slaby wrote:
> > > On 15. 05. 21, 10:45, Stafford Horne wrote:
> > > > Most litex boards using RISC-V soft cores us the sbi earlycon, however
> > > > this is not available for non RISC-V litex SoC. This patch enables
> > > > earlycon for liteuart which is available on all Litex SoC's making
> > > > support for earycon debugging more widely available.
> > > >
> > > > Signed-off-by: Stafford Horne <[email protected]>
> > > > Cc: Florent Kermarrec <[email protected]>
> > > > Cc: Mateusz Holenko <[email protected]>
> > > > Cc: Joel Stanley <[email protected]>
> > > > Cc: Gabriel L. Somlo <[email protected]>
> > > > ---
> > > > .../admin-guide/kernel-parameters.txt | 5 +++
> > > > drivers/tty/serial/Kconfig | 1 +
> > > > drivers/tty/serial/liteuart.c | 31 +++++++++++++++++++
> > > > 3 files changed, 37 insertions(+)
> > > >
> > > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > > > index 04545725f187..2d4a43af8de2 100644
> > > > --- a/Documentation/admin-guide/kernel-parameters.txt
> > > > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > > > @@ -1084,6 +1084,11 @@
> > > > the driver will use only 32-bit accessors to read/write
> > > > the device registers.
> > > > + liteuart,<addr>
> > > > + Start an early console on a litex serial port at the
> > > > + specified address. The serial port must already be
> > > > + setup and configured. Options are not yet supported.
> > > > +
> > > > meson,<addr>
> > > > Start an early, polled-mode console on a meson serial
> > > > port at the specified address. The serial port must
> > > > diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> > > > index 0c4cd4a348f4..9ceffe6ab6fd 100644
> > > > --- a/drivers/tty/serial/Kconfig
> > > > +++ b/drivers/tty/serial/Kconfig
> > > > @@ -1531,6 +1531,7 @@ config SERIAL_LITEUART
> > > > depends on OF || COMPILE_TEST
> > > > depends on LITEX
> > > > select SERIAL_CORE
> > > > + select SERIAL_EARLYCON
> > > > help
> > > > This driver is for the FPGA-based LiteUART serial controller from LiteX
> > > > SoC builder.
> > > > diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.c
> > > > index 64842f3539e1..38c472487e68 100644
> > > > --- a/drivers/tty/serial/liteuart.c
> > > > +++ b/drivers/tty/serial/liteuart.c
> > > > @@ -372,6 +372,37 @@ static int __init liteuart_console_init(void)
> > > > console_initcall(liteuart_console_init);
> > > > #endif /* CONFIG_SERIAL_LITEUART_CONSOLE */
> > > > +#ifdef CONFIG_SERIAL_EARLYCON
> > > > +static void early_liteuart_putc(struct uart_port *port, int c)
> > > > +{
> > > > + while (litex_read8(port->membase + OFF_TXFULL))
> > > > + cpu_relax();
> > > > +
> > > > + litex_write8(port->membase + OFF_RXTX, c);
> > >
> > > Hi,
> > >
> > > am I missing something or this doesn't differ to liteuart_putchar?
> >
> > Hi, No you are right, I missed that thanks for catching it.
> >
> > I should be able to remove this function and use putchar below.
>
> OK.
>
> I've just noticed you add an ifdef CONFIG_SERIAL_EARLYCON here, but you
> select SERIAL_EARLYCON in Kconfig above. So the ifdef is sort of pointless?
> (Or you shouldn't select SERIAL_EARLYCON.)
Ah yes, this I thought might have been wrong when I wrote it. I think my
problem here is I was just copying how some other patches implemented earlycon.
omap-serial - has ifdefs, doesn't select SERIAL_EARLYCON - looks ok
sifive - has ifdefs + select SERIAL_EARLYCON - maybe needs cleanup too
-Stafford