From ec84aa0a920192df56624961cb146947d7d9e11e Mon Sep 17 00:00:00 2001 From: Martin Blumenstingl Date: Sun, 11 Dec 2016 21:42:23 +0100 Subject: [PATCH] tty: serial: lantiq: implement earlycon support This allows enabling earlycon for devices with a Lantiq serial console by splitting lqasc_serial_port_write() from lqasc_console_write() and re-using the new function for earlycon's write callback. The kernel-parameter name matches the driver name ("lantiq"), similar to how other drivers implement this. Signed-off-by: Martin Blumenstingl Signed-off-by: Greg Kroah-Hartman --- .../admin-guide/kernel-parameters.txt | 6 +++ drivers/tty/serial/Kconfig | 1 + drivers/tty/serial/lantiq.c | 38 +++++++++++++++---- 3 files changed, 38 insertions(+), 7 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index be7c0d9506b1..52f13674bc21 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -966,6 +966,12 @@ serial port must already be setup and configured. Options are not yet supported. + lantiq, + Start an early, polled-mode console on a lantiq serial + (lqasc) port at the specified address. The serial port + must already be setup and configured. Options are not + yet supported. + lpuart, lpuart32, Use early console provided by Freescale LP UART driver diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig index e9cf5b67f1b7..6117ac8da48f 100644 --- a/drivers/tty/serial/Kconfig +++ b/drivers/tty/serial/Kconfig @@ -1161,6 +1161,7 @@ config SERIAL_LANTIQ depends on LANTIQ select SERIAL_CORE select SERIAL_CORE_CONSOLE + select SERIAL_EARLYCON help Support for console and UART on Lantiq SoCs. diff --git a/drivers/tty/serial/lantiq.c b/drivers/tty/serial/lantiq.c index b88832e8ee82..7c9a3f244935 100644 --- a/drivers/tty/serial/lantiq.c +++ b/drivers/tty/serial/lantiq.c @@ -590,13 +590,20 @@ lqasc_console_putchar(struct uart_port *port, int ch) ltq_w8(ch, port->membase + LTQ_ASC_TBUF); } +static void lqasc_serial_port_write(struct uart_port *port, const char *s, + u_int count) +{ + unsigned long flags; + + spin_lock_irqsave(<q_asc_lock, flags); + uart_console_write(port, s, count, lqasc_console_putchar); + spin_unlock_irqrestore(<q_asc_lock, flags); +} static void lqasc_console_write(struct console *co, const char *s, u_int count) { struct ltq_uart_port *ltq_port; - struct uart_port *port; - unsigned long flags; if (co->index >= MAXPORTS) return; @@ -605,11 +612,7 @@ lqasc_console_write(struct console *co, const char *s, u_int count) if (!ltq_port) return; - port = <q_port->port; - - spin_lock_irqsave(<q_asc_lock, flags); - uart_console_write(port, s, count, lqasc_console_putchar); - spin_unlock_irqrestore(<q_asc_lock, flags); + lqasc_serial_port_write(<q_port->port, s, count); } static int __init @@ -659,6 +662,27 @@ lqasc_console_init(void) } console_initcall(lqasc_console_init); +static void lqasc_serial_early_console_write(struct console *co, + const char *s, + u_int count) +{ + struct earlycon_device *dev = co->data; + + lqasc_serial_port_write(&dev->port, s, count); +} + +static int __init +lqasc_serial_early_console_setup(struct earlycon_device *device, + const char *opt) +{ + if (!device->port.membase) + return -ENODEV; + + device->con->write = lqasc_serial_early_console_write; + return 0; +} +OF_EARLYCON_DECLARE(lantiq, DRVNAME, lqasc_serial_early_console_setup); + static struct uart_driver lqasc_reg = { .owner = THIS_MODULE, .driver_name = DRVNAME, -- 2.20.1