diff options
| author | Stafford Horne <shorne@gmail.com> | 2021-05-17 20:54:52 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-05-20 16:35:01 +0200 |
| commit | 4bc2bd5aefd60a2837a20b1e88e89eaaa677d229 (patch) | |
| tree | 241992a1e59ccc796929c0912dad36088792464b | |
| parent | 758dfe3ddcae59b337d4109331f9be39da53b0ed (diff) | |
| download | linux-next-4bc2bd5aefd60a2837a20b1e88e89eaaa677d229.tar.gz | |
serial: liteuart: Add support for earlycon
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.
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>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Stafford Horne <shorne@gmail.com>
Link: https://lore.kernel.org/r/20210517115453.24365-1-shorne@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 5 | ||||
| -rw-r--r-- | drivers/tty/serial/Kconfig | 1 | ||||
| -rw-r--r-- | drivers/tty/serial/liteuart.c | 21 |
3 files changed, 27 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index cb89dbdedc46..17bdf5df404c 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1092,6 +1092,11 @@ 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 682f9171c82c..24282ad99d85 100644 --- a/drivers/tty/serial/Kconfig +++ b/drivers/tty/serial/Kconfig @@ -1553,6 +1553,7 @@ 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 0b06770642cb..dbc0559a9157 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) |