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Commit b94ba032 authored by Tomasz Figa's avatar Tomasz Figa Committed by Greg Kroah-Hartman
Browse files

serial: samsung: Add support for early console 



This patch adds support for early console initialized from device tree
and kernel command line to all variants of Samsung serial driver.

Signed-off-by: default avatarTomasz Figa <t.figa@samsung.com>
[mszyprow: added support for command line based initialization,
           fixed comments, added documentation]
Signed-off-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: default avatarAlim Akhtar <alim.akhtar@samsung.com>
Tested-by: default avatarAlim Akhtar <alim.akhtar@samsung.com>
Tested-by: default avatarChanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 8b6ff84c

Documentation/kernel-parameters.txt

+12 −0
Original line number Diff line number Diff line
@@ -970,6 +970,18 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 


		smh	Use ARM semihosting calls for early console.



		s3c2410,<addr>

		s3c2412,<addr>

		s3c2440,<addr>

		s3c6400,<addr>

		s5pv210,<addr>

		exynos4210,<addr>

			Use early console provided by serial driver available

			on Samsung SoCs, requires selecting proper type and

			a correct base address of the selected UART port. The

			serial port must already be setup and configured.

			Options are not yet supported.



	earlyprintk=	[X86,SH,BLACKFIN,ARM,M68k]

			earlyprintk=vga

			earlyprintk=efi

drivers/tty/serial/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -241,6 +241,7 @@ config SERIAL_SAMSUNG 
	tristate "Samsung SoC serial support"

	depends on PLAT_SAMSUNG || ARCH_EXYNOS

	select SERIAL_CORE

	select SERIAL_EARLYCON

	help

	  Support for the on-chip UARTs on the Samsung S3C24XX series CPUs,

	  providing /dev/ttySAC0, 1 and 2 (note, some machines may not

drivers/tty/serial/samsung.c

+103 −0
Original line number Diff line number Diff line
@@ -2403,6 +2403,109 @@ static struct platform_driver samsung_serial_driver = { 


module_platform_driver(samsung_serial_driver);



/*

 * Early console.

 */



struct samsung_early_console_data {

	u32 txfull_mask;

};



static void samsung_early_busyuart(struct uart_port *port)

{

	while (!(readl(port->membase + S3C2410_UTRSTAT) & S3C2410_UTRSTAT_TXFE))

		;

}



static void samsung_early_busyuart_fifo(struct uart_port *port)

{

	struct samsung_early_console_data *data = port->private_data;



	while (readl(port->membase + S3C2410_UFSTAT) & data->txfull_mask)

		;

}



static void samsung_early_putc(struct uart_port *port, int c)

{

	if (readl(port->membase + S3C2410_UFCON) & S3C2410_UFCON_FIFOMODE)

		samsung_early_busyuart_fifo(port);

	else

		samsung_early_busyuart(port);



	writeb(c, port->membase + S3C2410_UTXH);

}



static void samsung_early_write(struct console *con, const char *s, unsigned n)

{

	struct earlycon_device *dev = con->data;



	uart_console_write(&dev->port, s, n, samsung_early_putc);

}



static int __init samsung_early_console_setup(struct earlycon_device *device,

					      const char *opt)

{

	if (!device->port.membase)

		return -ENODEV;



	device->con->write = samsung_early_write;

	return 0;

}



/* S3C2410 */

static struct samsung_early_console_data s3c2410_early_console_data = {

	.txfull_mask = S3C2410_UFSTAT_TXFULL,

};



static int __init s3c2410_early_console_setup(struct earlycon_device *device,

					      const char *opt)

{

	device->port.private_data = &s3c2410_early_console_data;

	return samsung_early_console_setup(device, opt);

}

OF_EARLYCON_DECLARE(s3c2410, "samsung,s3c2410-uart",

			s3c2410_early_console_setup);

EARLYCON_DECLARE(s3c2410, s3c2410_early_console_setup);



/* S3C2412, S3C2440, S3C64xx */

static struct samsung_early_console_data s3c2440_early_console_data = {

	.txfull_mask = S3C2440_UFSTAT_TXFULL,

};



static int __init s3c2440_early_console_setup(struct earlycon_device *device,

					      const char *opt)

{

	device->port.private_data = &s3c2440_early_console_data;

	return samsung_early_console_setup(device, opt);

}

OF_EARLYCON_DECLARE(s3c2412, "samsung,s3c2412-uart",

			s3c2440_early_console_setup);

OF_EARLYCON_DECLARE(s3c2440, "samsung,s3c2440-uart",

			s3c2440_early_console_setup);

OF_EARLYCON_DECLARE(s3c6400, "samsung,s3c6400-uart",

			s3c2440_early_console_setup);

EARLYCON_DECLARE(s3c2412, s3c2440_early_console_setup);

EARLYCON_DECLARE(s3c2440, s3c2440_early_console_setup);

EARLYCON_DECLARE(s3c6400, s3c2440_early_console_setup);



/* S5PV210, EXYNOS */

static struct samsung_early_console_data s5pv210_early_console_data = {

	.txfull_mask = S5PV210_UFSTAT_TXFULL,

};



static int __init s5pv210_early_console_setup(struct earlycon_device *device,

					      const char *opt)

{

	device->port.private_data = &s5pv210_early_console_data;

	return samsung_early_console_setup(device, opt);

}

OF_EARLYCON_DECLARE(s5pv210, "samsung,s5pv210-uart",

			s5pv210_early_console_setup);

OF_EARLYCON_DECLARE(exynos4210, "samsung,exynos4210-uart",

			s5pv210_early_console_setup);

EARLYCON_DECLARE(s5pv210, s5pv210_early_console_setup);

EARLYCON_DECLARE(exynos4210, s5pv210_early_console_setup);



MODULE_ALIAS("platform:samsung-uart");

MODULE_DESCRIPTION("Samsung SoC Serial port driver");

MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");