tty/serial: convert 8250 to generic earlycon (d2fd6810) · Commits · e / devices / android_kernel_oneplus_sm8150

drivers/tty/serial/8250/8250_early.c

+15 −123

Original line number	Diff line number	Diff line
		@@ -35,18 +35,8 @@
		#include <linux/serial_8250.h>
		#include <asm/io.h>
		#include <asm/serial.h>
		#ifdef CONFIG_FIX_EARLYCON_MEM
		#include <asm/pgtable.h>
		#include <asm/fixmap.h>
		#endif

		struct early_serial8250_device {
		struct uart_port port;
		char options[16]; /* e.g., 115200n8 */
		unsigned int baud;
		};

		static struct early_serial8250_device early_device;
		static struct earlycon_device *early_device;

		unsigned int __weak __init serial8250_early_in(struct uart_port *port, int offset)
		{
		@@ -100,7 +90,7 @@ static void __init serial_putc(struct uart_port *port, int c)
		static void __init early_serial8250_write(struct console *console,
		const char *s, unsigned int count)
		{
		struct uart_port *port = &early_device.port;
		struct uart_port *port = &early_device->port;
		unsigned int ier;

		/* Save the IER and disable interrupts */
		@@ -129,7 +119,7 @@ static unsigned int __init probe_baud(struct uart_port *port)
		return (port->uartclk / 16) / quot;
		}

		static void __init init_port(struct early_serial8250_device *device)
		static void __init init_port(struct earlycon_device *device)
		{
		struct uart_port *port = &device->port;
		unsigned int divisor;
		@@ -148,128 +138,32 @@ static void __init init_port(struct early_serial8250_device *device)
		serial8250_early_out(port, UART_LCR, c & ~UART_LCR_DLAB);
		}

		static int __init parse_options(struct early_serial8250_device *device,
		char *options)
		{
		struct uart_port *port = &device->port;
		int mmio, mmio32, length;

		if (!options)
		return -ENODEV;

		port->uartclk = BASE_BAUD * 16;

		mmio = !strncmp(options, "mmio,", 5);
		mmio32 = !strncmp(options, "mmio32,", 7);
		if (mmio \|\| mmio32) {
		port->iotype = (mmio ? UPIO_MEM : UPIO_MEM32);
		port->mapbase = simple_strtoul(options + (mmio ? 5 : 7),
		&options, 0);
		if (mmio32)
		port->regshift = 2;
		#ifdef CONFIG_FIX_EARLYCON_MEM
		set_fixmap_nocache(FIX_EARLYCON_MEM_BASE,
		port->mapbase & PAGE_MASK);
		port->membase =
		(void __iomem *)__fix_to_virt(FIX_EARLYCON_MEM_BASE);
		port->membase += port->mapbase & ~PAGE_MASK;
		#else
		port->membase = ioremap_nocache(port->mapbase, 64);
		if (!port->membase) {
		printk(KERN_ERR "%s: Couldn't ioremap 0x%llx\n",
		__func__,
		(unsigned long long) port->mapbase);
		return -ENOMEM;
		}
		#endif
		} else if (!strncmp(options, "io,", 3)) {
		port->iotype = UPIO_PORT;
		port->iobase = simple_strtoul(options + 3, &options, 0);
		mmio = 0;
		} else
		return -EINVAL;

		options = strchr(options, ',');
		if (options) {
		options++;
		device->baud = simple_strtoul(options, NULL, 0);
		length = min(strcspn(options, " ") + 1,
		(size_t)(sizeof(device->options)));
		strlcpy(device->options, options, length);
		} else {
		device->baud = probe_baud(port);
		snprintf(device->options, sizeof(device->options), "%u",
		device->baud);
		}

		if (mmio \|\| mmio32)
		printk(KERN_INFO
		"Early serial console at MMIO%s 0x%llx (options '%s')\n",
		mmio32 ? "32" : "",
		(unsigned long long)port->mapbase,
		device->options);
		else
		printk(KERN_INFO
		"Early serial console at I/O port 0x%lx (options '%s')\n",
		port->iobase,
		device->options);

		return 0;
		}

		static struct console early_serial8250_console __initdata = {
		.name = "uart",
		.write = early_serial8250_write,
		.flags = CON_PRINTBUFFER \| CON_BOOT,
		.index = -1,
		};

		static int __init early_serial8250_setup(char *options)
		static int __init early_serial8250_setup(struct earlycon_device *device,
		const char *options)
		{
		struct early_serial8250_device *device = &early_device;
		int err;

		if (device->port.membase \|\| device->port.iobase)
		if (!(device->port.membase \|\| device->port.iobase))
		return 0;

		err = parse_options(device, options);
		if (err < 0)
		return err;
		if (!device->baud)
		device->baud = probe_baud(&device->port);

		init_port(device);
		return 0;
		}

		int __init setup_early_serial8250_console(char *cmdline)
		{
		char *options;
		int err;

		options = strstr(cmdline, "uart8250,");
		if (!options) {
		options = strstr(cmdline, "uart,");
		if (!options)
		return 0;
		}

		options = strchr(cmdline, ',') + 1;
		err = early_serial8250_setup(options);
		if (err < 0)
		return err;

		register_console(&early_serial8250_console);

		early_device = device;
		device->con->write = early_serial8250_write;
		return 0;
		}
		EARLYCON_DECLARE(uart8250, early_serial8250_setup);
		EARLYCON_DECLARE(uart, early_serial8250_setup);

		int serial8250_find_port_for_earlycon(void)
		{
		struct early_serial8250_device *device = &early_device;
		struct uart_port *port = &device->port;
		struct earlycon_device *device = early_device;
		struct uart_port *port = device ? &device->port : NULL;
		int line;
		int ret;

		if (!device->port.membase && !device->port.iobase)
		if (!port \|\| (!port->membase && !port->iobase))
		return -ENODEV;

		line = serial8250_find_port(port);
		@@ -284,5 +178,3 @@ int serial8250_find_port_for_earlycon(void)

		return ret;
		}

		early_param("earlycon", setup_early_serial8250_console);

drivers/tty/serial/8250/Kconfig

+1 −0

Original line number	Diff line number	Diff line
		@@ -61,6 +61,7 @@ config SERIAL_8250_CONSOLE
		bool "Console on 8250/16550 and compatible serial port"
		depends on SERIAL_8250=y
		select SERIAL_CORE_CONSOLE
		select SERIAL_EARLYCON
		---help---
		If you say Y here, it will be possible to use a serial port as the
		system console (the system console is the device which receives all