Messages in this thread |  | | Subject | Re: [PATCH v2] serial: liteuart: Add support for earlycon | | From | Jiri Slaby <> | | Date | Tue, 18 May 2021 06:57:34 +0200 |
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On 17. 05. 21, 13:54, 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's. 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> > Reviewed-and-tested-by: Gabriel Somlo <gsomlo@gmail.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
> --- > Changes since v1: > - Fixed subject > - Fixed ifdef and config issues pointed out by Jiri > - Use liteuart_putchar instead of early_liteuart_putc > > .../admin-guide/kernel-parameters.txt | 5 +++++ > drivers/tty/serial/Kconfig | 1 + > drivers/tty/serial/liteuart.c | 21 +++++++++++++++++++ > 3 files changed, 27 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..af41e534483c 100644 > --- a/drivers/tty/serial/Kconfig > +++ b/drivers/tty/serial/Kconfig > @@ -1550,6 +1550,7 @@ config SERIAL_LITEUART_CONSOLE > bool "LiteUART serial port console support" > depends on SERIAL_LITEUART=y > select SERIAL_CORE_CONSOLE > + select SERIAL_EARLYCON > help > Say 'Y' or 'M' here if you wish to use the FPGA-based LiteUART serial > controller from LiteX SoC builder as the system console > diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.c > index 64842f3539e1..1b75a4bf7c56 100644 > --- a/drivers/tty/serial/liteuart.c > +++ b/drivers/tty/serial/liteuart.c > @@ -370,6 +370,27 @@ static int __init liteuart_console_init(void) > return 0; > } > console_initcall(liteuart_console_init); > + > +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, liteuart_putchar); > +} > + > +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_LITEUART_CONSOLE */ > > static int __init liteuart_init(void) >
thanks, -- js suse labs
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