serial: samsung: Add support for early console (b94ba032) · Commits · 戴 / test

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>");

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