* Re: [PATCH] serial/liteuart; Add support for earlycon
2021-05-15 8:45 [PATCH] serial/liteuart; Add support for earlycon Stafford Horne
@ 2021-05-15 8:49 ` Stafford Horne
2021-05-15 12:17 ` Gabriel L. Somlo
2021-05-17 8:16 ` Jiri Slaby
2 siblings, 0 replies; 7+ messages in thread
From: Stafford Horne @ 2021-05-15 8:49 UTC (permalink / raw)
To: LKML
Cc: Florent Kermarrec, Mateusz Holenko, Joel Stanley,
Gabriel L . Somlo, Jonathan Corbet, Greg Kroah-Hartman,
Jiri Slaby, Karol Gugala, Paul E. McKenney, Randy Dunlap,
Andrew Morton, Thomas Gleixner, Viresh Kumar, Mike Kravetz,
Peter Zijlstra, linux-doc, linux-serial
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 <shorne@gmail.com>
> Cc: Florent Kermarrec <florent@enjoy-digital.fr>
> Cc: Mateusz Holenko <mholenko@antmicro.com>
> Cc: Joel Stanley <joel@jms.id.au>
> Cc: Gabriel L. Somlo <gsomlo@gmail.com>
> ---
> .../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
>
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] serial/liteuart; Add support for earlycon
2021-05-15 8:45 [PATCH] serial/liteuart; Add support for earlycon Stafford Horne
2021-05-15 8:49 ` Stafford Horne
@ 2021-05-15 12:17 ` Gabriel L. Somlo
2021-05-17 8:16 ` Jiri Slaby
2 siblings, 0 replies; 7+ messages in thread
From: Gabriel L. Somlo @ 2021-05-15 12:17 UTC (permalink / raw)
To: Stafford Horne
Cc: LKML, Florent Kermarrec, Mateusz Holenko, Joel Stanley,
Jonathan Corbet, Greg Kroah-Hartman, Jiri Slaby, Karol Gugala,
Paul E. McKenney, Randy Dunlap, Andrew Morton, Thomas Gleixner,
Viresh Kumar, Mike Kravetz, Peter Zijlstra, linux-doc,
linux-serial
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 <shorne@gmail.com>
> Cc: Florent Kermarrec <florent@enjoy-digital.fr>
> Cc: Mateusz Holenko <mholenko@antmicro.com>
> Cc: Joel Stanley <joel@jms.id.au>
> Cc: Gabriel L. Somlo <gsomlo@gmail.com>
> ---
> .../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 <gsomlo@gmail.com>
Thanks,
--Gabriel
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] serial/liteuart; Add support for earlycon
2021-05-15 8:45 [PATCH] serial/liteuart; Add support for earlycon Stafford Horne
2021-05-15 8:49 ` Stafford Horne
2021-05-15 12:17 ` Gabriel L. Somlo
@ 2021-05-17 8:16 ` Jiri Slaby
2021-05-17 8:23 ` Stafford Horne
2 siblings, 1 reply; 7+ messages in thread
From: Jiri Slaby @ 2021-05-17 8:16 UTC (permalink / raw)
To: Stafford Horne, LKML
Cc: Florent Kermarrec, Mateusz Holenko, Joel Stanley,
Gabriel L . Somlo, Jonathan Corbet, Greg Kroah-Hartman,
Karol Gugala, Paul E. McKenney, Randy Dunlap, Andrew Morton,
Thomas Gleixner, Viresh Kumar, Mike Kravetz, Peter Zijlstra,
linux-doc, linux-serial
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 <shorne@gmail.com>
> Cc: Florent Kermarrec <florent@enjoy-digital.fr>
> Cc: Mateusz Holenko <mholenko@antmicro.com>
> Cc: Joel Stanley <joel@jms.id.au>
> Cc: Gabriel L. Somlo <gsomlo@gmail.com>
> ---
> .../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
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] serial/liteuart; Add support for earlycon
2021-05-17 8:16 ` Jiri Slaby
@ 2021-05-17 8:23 ` Stafford Horne
2021-05-17 8:25 ` Jiri Slaby
0 siblings, 1 reply; 7+ messages in thread
From: Stafford Horne @ 2021-05-17 8:23 UTC (permalink / raw)
To: Jiri Slaby
Cc: LKML, Florent Kermarrec, Mateusz Holenko, Joel Stanley,
Gabriel L . Somlo, Jonathan Corbet, Greg Kroah-Hartman,
Karol Gugala, Paul E. McKenney, Randy Dunlap, Andrew Morton,
Thomas Gleixner, Viresh Kumar, Mike Kravetz, Peter Zijlstra,
linux-doc, linux-serial
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 <shorne@gmail.com>
> > Cc: Florent Kermarrec <florent@enjoy-digital.fr>
> > Cc: Mateusz Holenko <mholenko@antmicro.com>
> > Cc: Joel Stanley <joel@jms.id.au>
> > Cc: Gabriel L. Somlo <gsomlo@gmail.com>
> > ---
> > .../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
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] serial/liteuart; Add support for earlycon
2021-05-17 8:23 ` Stafford Horne
@ 2021-05-17 8:25 ` Jiri Slaby
2021-05-17 8:53 ` Stafford Horne
0 siblings, 1 reply; 7+ messages in thread
From: Jiri Slaby @ 2021-05-17 8:25 UTC (permalink / raw)
To: Stafford Horne
Cc: LKML, Florent Kermarrec, Mateusz Holenko, Joel Stanley,
Gabriel L . Somlo, Jonathan Corbet, Greg Kroah-Hartman,
Karol Gugala, Paul E. McKenney, Randy Dunlap, Andrew Morton,
Thomas Gleixner, Viresh Kumar, Mike Kravetz, Peter Zijlstra,
linux-doc, linux-serial
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 <shorne@gmail.com>
>>> Cc: Florent Kermarrec <florent@enjoy-digital.fr>
>>> Cc: Mateusz Holenko <mholenko@antmicro.com>
>>> Cc: Joel Stanley <joel@jms.id.au>
>>> Cc: Gabriel L. Somlo <gsomlo@gmail.com>
>>> ---
>>> .../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
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH] serial/liteuart; Add support for earlycon
2021-05-17 8:25 ` Jiri Slaby
@ 2021-05-17 8:53 ` Stafford Horne
0 siblings, 0 replies; 7+ messages in thread
From: Stafford Horne @ 2021-05-17 8:53 UTC (permalink / raw)
To: Jiri Slaby
Cc: LKML, Florent Kermarrec, Mateusz Holenko, Joel Stanley,
Gabriel L . Somlo, Jonathan Corbet, Greg Kroah-Hartman,
Karol Gugala, Paul E. McKenney, Randy Dunlap, Andrew Morton,
Thomas Gleixner, Viresh Kumar, Mike Kravetz, Peter Zijlstra,
linux-doc, linux-serial
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 <shorne@gmail.com>
> > > > Cc: Florent Kermarrec <florent@enjoy-digital.fr>
> > > > Cc: Mateusz Holenko <mholenko@antmicro.com>
> > > > Cc: Joel Stanley <joel@jms.id.au>
> > > > Cc: Gabriel L. Somlo <gsomlo@gmail.com>
> > > > ---
> > > > .../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
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