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Commit 913c6c0e authored by Lucas Stach's avatar Lucas Stach Committed by Greg Kroah-Hartman
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serial: imx: add earlycon support 



Earlycon allows to have an early debugging console that doesn't need
to be statically configured in the kernel config, like earlyprintk,
but is set up through the stdout-path DT property.

This allows to have the early debugging always built into the
kernel and enabled on demand without clashing between different boards
or architectures.

Signed-off-by: default avatarLucas Stach <l.stach@pengutronix.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4cad4c57

drivers/tty/serial/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -582,6 +582,7 @@ config SERIAL_IMX_CONSOLE 
	bool "Console on IMX serial port"

	depends on SERIAL_IMX=y

	select SERIAL_CORE_CONSOLE

	select SERIAL_EARLYCON if OF

	help

	  If you have enabled the serial port on the Freescale IMX

	  CPU you can make it the console by answering Y to this option.

drivers/tty/serial/imx.c

+32 −0
Original line number Diff line number Diff line
@@ -1795,6 +1795,38 @@ static struct console imx_console = { 
};



#define IMX_CONSOLE	&imx_console



#ifdef CONFIG_OF

static void imx_console_early_putchar(struct uart_port *port, int ch)

{

	while (readl_relaxed(port->membase + IMX21_UTS) & UTS_TXFULL)

		cpu_relax();



	writel_relaxed(ch, port->membase + URTX0);

}



static void imx_console_early_write(struct console *con, const char *s,

				    unsigned count)

{

	struct earlycon_device *dev = con->data;



	uart_console_write(&dev->port, s, count, imx_console_early_putchar);

}



static int __init

imx_console_early_setup(struct earlycon_device *dev, const char *opt)

{

	if (!dev->port.membase)

		return -ENODEV;



	dev->con->write = imx_console_early_write;



	return 0;

}

OF_EARLYCON_DECLARE(ec_imx6q, "fsl,imx6q-uart", imx_console_early_setup);

OF_EARLYCON_DECLARE(ec_imx21, "fsl,imx21-uart", imx_console_early_setup);

#endif



#else

#define IMX_CONSOLE	NULL

#endif