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Commit 736d5538 authored by Andreas Färber's avatar Andreas Färber Committed by Greg Kroah-Hartman
Browse files

tty: serial: meson: Implement earlycon support 



Split off the bulk of the existing meson_serial_console_write()
implementation into meson_serial_port_write() for implementing
meson_serial_early_console_write().

Use "meson" as the earlycon driver name, courtesy of Nicolas.

Signed-off-by: default avatarNicolas Saenz Julienne <nicolassaenzj@gmail.com>
Acked-by: default avatarCarlo Caione <carlo@endlessm.com>
Signed-off-by: default avatarAndreas Färber <afaerber@suse.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 79c9473f

Documentation/kernel-parameters.txt

+6 −0
Original line number Diff line number Diff line
@@ -1039,6 +1039,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 
			the driver will use only 32-bit accessors to read/write

			the device registers.



		meson,<addr>

			Start an early, polled-mode console on a meson serial

			port at the specified address. The serial port must

			already be setup and configured. Options are not yet

			supported.



		msm_serial,<addr>

			Start an early, polled-mode console on an msm serial

			port at the specified address. The serial port

drivers/tty/serial/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -213,6 +213,7 @@ config SERIAL_MESON_CONSOLE 
	bool "Support for console on meson"

	depends on SERIAL_MESON=y

	select SERIAL_CORE_CONSOLE

	select SERIAL_EARLYCON

	help

	  Say Y here if you wish to use a Amlogic MesonX UART as the

	  system console (the system console is the device which

drivers/tty/serial/meson_uart.c

+35 −7
Original line number Diff line number Diff line
@@ -481,18 +481,13 @@ static void meson_console_putchar(struct uart_port *port, int ch) 
	writel(ch, port->membase + AML_UART_WFIFO);

}



static void meson_serial_console_write(struct console *co, const char *s,

static void meson_serial_port_write(struct uart_port *port, const char *s,

				    u_int count)

{

	struct uart_port *port;

	unsigned long flags;

	int locked;

	u32 val, tmp;



	port = meson_ports[co->index];

	if (!port)

		return;



	local_irq_save(flags);

	if (port->sysrq) {

		locked = 0;
@@ -516,6 +511,18 @@ static void meson_serial_console_write(struct console *co, const char *s, 
	local_irq_restore(flags);

}



static void meson_serial_console_write(struct console *co, const char *s,

				       u_int count)

{

	struct uart_port *port;



	port = meson_ports[co->index];

	if (!port)

		return;



	meson_serial_port_write(port, s, count);

}



static int meson_serial_console_setup(struct console *co, char *options)

{

	struct uart_port *port;
@@ -554,6 +561,27 @@ static int __init meson_serial_console_init(void) 
}

console_initcall(meson_serial_console_init);



static void meson_serial_early_console_write(struct console *co,

					     const char *s,

					     u_int count)

{

	struct earlycon_device *dev = co->data;



	meson_serial_port_write(&dev->port, s, count);

}



static int __init

meson_serial_early_console_setup(struct earlycon_device *device, const char *opt)

{

	if (!device->port.membase)

		return -ENODEV;



	device->con->write = meson_serial_early_console_write;

	return 0;

}

OF_EARLYCON_DECLARE(meson, "amlogic,meson-uart",

		    meson_serial_early_console_setup);



#define MESON_SERIAL_CONSOLE	(&meson_serial_console)

#else

#define MESON_SERIAL_CONSOLE	NULL