From bd8d257fa3371a284568b8ee04c2bcf4757238ed Mon Sep 17 00:00:00 2001 From: Vladimir Murzin Date: Mon, 25 Apr 2016 09:47:48 +0100 Subject: serial: mps2-uart: add support for early console This adds support early console for MPS2 UART which can be enabled via earlycon=mps2,0x40004000 Acked-by: Greg Kroah-Hartman Reviewed-by: Peter Hurley Signed-off-by: Vladimir Murzin Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/Kconfig | 1 + drivers/tty/serial/mps2-uart.c | 28 ++++++++++++++++++++++++++++ 2 files changed, 29 insertions(+) (limited to 'drivers/tty') diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig index 3b0a9b3ec4e1..331638db6466 100644 --- a/drivers/tty/serial/Kconfig +++ b/drivers/tty/serial/Kconfig @@ -1452,6 +1452,7 @@ config SERIAL_MPS2_UART_CONSOLE bool "MPS2 UART console support" depends on SERIAL_MPS2_UART select SERIAL_CORE_CONSOLE + select SERIAL_EARLYCON config SERIAL_MPS2_UART bool "MPS2 UART port" diff --git a/drivers/tty/serial/mps2-uart.c b/drivers/tty/serial/mps2-uart.c index e571e4cdfab3..da9e27d3c263 100644 --- a/drivers/tty/serial/mps2-uart.c +++ b/drivers/tty/serial/mps2-uart.c @@ -450,6 +450,34 @@ static struct console mps2_uart_console = { #define MPS2_SERIAL_CONSOLE (&mps2_uart_console) +static void mps2_early_putchar(struct uart_port *port, int ch) +{ + while (readb(port->membase + UARTn_STATE) & UARTn_STATE_TX_FULL) + cpu_relax(); + + writeb((unsigned char)ch, port->membase + UARTn_DATA); +} + +static void mps2_early_write(struct console *con, const char *s, unsigned int n) +{ + struct earlycon_device *dev = con->data; + + uart_console_write(&dev->port, s, n, mps2_early_putchar); +} + +static int __init mps2_early_console_setup(struct earlycon_device *device, + const char *opt) +{ + if (!device->port.membase) + return -ENODEV; + + device->con->write = mps2_early_write; + + return 0; +} + +OF_EARLYCON_DECLARE(mps2, "arm,mps2-uart", mps2_early_console_setup); + #else #define MPS2_SERIAL_CONSOLE NULL #endif -- cgit v1.2.3