Commit 18a8bd94 authored by Yinghai Lu's avatar Yinghai Lu Committed by Linus Torvalds
Browse files

serial: convert early_uart to earlycon for 8250 



Beacuse SERIAL_PORT_DFNS is removed from include/asm-i386/serial.h and
include/asm-x86_64/serial.h.  the serial8250_ports need to be probed late in
serial initializing stage.  the console_init=>serial8250_console_init=>
register_console=>serial8250_console_setup will return -ENDEV, and console
ttyS0 can not be enabled at that time.  need to wait till uart_add_one_port in
drivers/serial/serial_core.c to call register_console to get console ttyS0.
that is too late.

Make early_uart to use early_param, so uart console can be used earlier.  Make
it to be bootconsole with CON_BOOT flag, so can use console handover feature.
and it will switch to corresponding normal serial console automatically.

new command line will be:
	console=uart8250,io,0x3f8,9600n8
	console=uart8250,mmio,0xff5e0000,115200n8
or
	earlycon=uart8250,io,0x3f8,9600n8
	earlycon=uart8250,mmio,0xff5e0000,115200n8

it will print in very early stage:
	Early serial console at I/O port 0x3f8 (options '9600n8')
	console [uart0] enabled
later for console it will print:
	console handover: boot [uart0] -> real [ttyS0]

Signed-off-by: default avatar <yinghai.lu@sun.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b1c931e3

Documentation/kernel-parameters.txt

+9 −2
Original line number Diff line number Diff line
@@ -462,13 +462,20 @@ and is between 256 and 4096 characters. It is defined in the file 
			Documentation/networking/netconsole.txt for an

			alternative.



		uart,io,<addr>[,options]

		uart,mmio,<addr>[,options]

		uart[8250],io,<addr>[,options]

		uart[8250],mmio,<addr>[,options]

			Start an early, polled-mode console on the 8250/16550

			UART at the specified I/O port or MMIO address,

			switching to the matching ttyS device later.  The

			options are the same as for ttyS, above.



	earlycon=	[KNL] Output early console device and options.

		uart[8250],io,<addr>[,options]

		uart[8250],mmio,<addr>[,options]

			Start an early, polled-mode console on the 8250/16550

			UART at the specified I/O port or MMIO address.

			The options are the same as for ttyS, above.



	cpcihp_generic=	[HW,PCI] Generic port I/O CompactPCI driver

			Format:

			<first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]

arch/ia64/kernel/setup.c

+0 −4
Original line number Diff line number Diff line
@@ -390,10 +390,6 @@ early_console_setup (char *cmdline) 
	if (!efi_setup_pcdp_console(cmdline))

		earlycons++;

#endif

#ifdef CONFIG_SERIAL_8250_CONSOLE

	if (!early_serial_console_init(cmdline))

		earlycons++;

#endif



	return (earlycons) ? 0 : -1;

}

drivers/firmware/pcdp.c

+4 −2
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
#include <linux/console.h>

#include <linux/efi.h>

#include <linux/serial.h>

#include <linux/serial_8250.h>

#include <asm/vga.h>

#include "pcdp.h"
@@ -27,7 +28,7 @@ setup_serial_console(struct pcdp_uart *uart) 
	char parity;



	mmio = (uart->addr.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY);

	p += sprintf(p, "console=uart,%s,0x%lx",

	p += sprintf(p, "uart8250,%s,0x%lx",

		mmio ? "mmio" : "io", uart->addr.address);

	if (uart->baud) {

		p += sprintf(p, ",%lu", uart->baud);
@@ -41,7 +42,8 @@ setup_serial_console(struct pcdp_uart *uart) 
		}

	}



	return early_serial_console_init(options);

	add_preferred_console("uart", 8250, &options[9]);

	return setup_early_serial8250_console(options);

#else

	return -ENODEV;

#endif

drivers/serial/8250.c

+7 −21
Original line number Diff line number Diff line
@@ -2514,12 +2514,18 @@ static int __init serial8250_console_setup(struct console *co, char *options) 
	return uart_set_options(port, co, baud, parity, bits, flow);

}



static int __init serial8250_console_early_setup(void)

{

	return serial8250_find_port_for_earlycon();

}



static struct uart_driver serial8250_reg;

static struct console serial8250_console = {

	.name		= "ttyS",

	.write		= serial8250_console_write,

	.device		= uart_console_device,

	.setup		= serial8250_console_setup,

	.early_setup	= serial8250_console_early_setup,

	.flags		= CON_PRINTBUFFER,

	.index		= -1,

	.data		= &serial8250_reg,
@@ -2533,7 +2539,7 @@ static int __init serial8250_console_init(void) 
}

console_initcall(serial8250_console_init);



static int __init find_port(struct uart_port *p)

int serial8250_find_port(struct uart_port *p)

{

	int line;

	struct uart_port *port;
@@ -2546,26 +2552,6 @@ static int __init find_port(struct uart_port *p) 
	return -ENODEV;

}



int __init serial8250_start_console(struct uart_port *port, char *options)

{

	int line;



	line = find_port(port);

	if (line < 0)

		return -ENODEV;



	add_preferred_console("ttyS", line, options);

	printk("Adding console on ttyS%d at %s 0x%lx (options '%s')\n",

		line, port->iotype == UPIO_MEM ? "MMIO" : "I/O port",

		port->iotype == UPIO_MEM ? (unsigned long) port->mapbase :

		    (unsigned long) port->iobase, options);

	if (!(serial8250_console.flags & CON_ENABLED)) {

		serial8250_console.flags &= ~CON_PRINTBUFFER;

		register_console(&serial8250_console);

	}

	return line;

}



#define SERIAL8250_CONSOLE	&serial8250_console

#else

#define SERIAL8250_CONSOLE	NULL

drivers/serial/8250_early.c

+59 −58
Original line number Diff line number Diff line
@@ -17,13 +17,11 @@ 
 * we locate the device directly by its MMIO or I/O port address.

 *

 * The user can specify the device directly, e.g.,

 *	console=uart,io,0x3f8,9600n8

 *	console=uart,mmio,0xff5e0000,115200n8

 * or platform code can call early_uart_console_init() to set

 * the early UART device.

 *

 * After the normal serial driver starts, we try to locate the

 * matching ttyS device and start a console there.

 *	earlycon=uart8250,io,0x3f8,9600n8

 *	earlycon=uart8250,mmio,0xff5e0000,115200n8

 * or

 *	console=uart8250,io,0x3f8,9600n8

 *	console=uart8250,mmio,0xff5e0000,115200n8

 */



#include <linux/tty.h>
@@ -32,17 +30,21 @@ 
#include <linux/serial_core.h>

#include <linux/serial_reg.h>

#include <linux/serial.h>

#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_uart_device {

struct early_serial8250_device {

	struct uart_port port;

	char options[16];		/* e.g., 115200n8 */

	unsigned int baud;

};



static struct early_uart_device early_device __initdata;

static int early_uart_registered __initdata;

static struct early_serial8250_device early_device;



static unsigned int __init serial_in(struct uart_port *port, int offset)

{
@@ -80,7 +82,7 @@ static void __init putc(struct uart_port *port, int c) 
	serial_out(port, UART_TX, c);

}



static void __init early_uart_write(struct console *console, const char *s, unsigned int count)

static void __init early_serial8250_write(struct console *console, const char *s, unsigned int count)

{

	struct uart_port *port = &early_device.port;

	unsigned int ier;
@@ -111,7 +113,7 @@ static unsigned int __init probe_baud(struct uart_port *port) 
	return (port->uartclk / 16) / quot;

}



static void __init init_port(struct early_uart_device *device)

static void __init init_port(struct early_serial8250_device *device)

{

	struct uart_port *port = &device->port;

	unsigned int divisor;
@@ -130,10 +132,9 @@ static void __init init_port(struct early_uart_device *device) 
	serial_out(port, UART_LCR, c & ~UART_LCR_DLAB);

}



static int __init parse_options(struct early_uart_device *device, char *options)

static int __init parse_options(struct early_serial8250_device *device, char *options)

{

	struct uart_port *port = &device->port;

	int mapsize = 64;

	int mmio, length;



	if (!options)
@@ -143,12 +144,18 @@ static int __init parse_options(struct early_uart_device *device, char *options) 
	if (!strncmp(options, "mmio,", 5)) {

		port->iotype = UPIO_MEM;

		port->mapbase = simple_strtoul(options + 5, &options, 0);

		port->membase = ioremap(port->mapbase, mapsize);

#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(port->mapbase, 64);

		if (!port->membase) {

			printk(KERN_ERR "%s: Couldn't ioremap 0x%lx\n",

				__FUNCTION__, port->mapbase);

			return -ENOMEM;

		}

#endif

		mmio = 1;

	} else if (!strncmp(options, "io,", 3)) {

		port->iotype = UPIO_PORT;
@@ -175,9 +182,16 @@ static int __init parse_options(struct early_uart_device *device, char *options) 
	return 0;

}



static int __init early_uart_setup(struct console *console, char *options)

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)

{

	struct early_uart_device *device = &early_device;

	struct early_serial8250_device *device = &early_device;

	int err;



	if (device->port.membase || device->port.iobase)
@@ -190,61 +204,48 @@ static int __init early_uart_setup(struct console *console, char *options) 
	return 0;

}



static struct console early_uart_console __initdata = {

	.name	= "uart",

	.write	= early_uart_write,

	.setup	= early_uart_setup,

	.flags	= CON_PRINTBUFFER,

	.index	= -1,

};



static int __init early_uart_console_init(void)

{

	if (!early_uart_registered) {

		register_console(&early_uart_console);

		early_uart_registered = 1;

	}

	return 0;

}

console_initcall(early_uart_console_init);



int __init early_serial_console_init(char *cmdline)

int __init setup_early_serial8250_console(char *cmdline)

{

	char *options;

	int err;



	options = strstr(cmdline, "console=uart,");

	options = strstr(cmdline, "uart8250,");

	if (!options) {

		options = strstr(cmdline, "uart,");

		if (!options)

		return -ENODEV;

			return 0;

	}



	options = strchr(cmdline, ',') + 1;

	if ((err = early_uart_setup(NULL, options)) < 0)

	if ((err = early_serial8250_setup(options)) < 0)

		return err;

	return early_uart_console_init();



	register_console(&early_serial8250_console);



	return 0;

}



static int __init early_uart_console_switch(void)

int __init serial8250_find_port_for_earlycon(void)

{

	struct early_uart_device *device = &early_device;

	struct early_serial8250_device *device = &early_device;

	struct uart_port *port = &device->port;

	int mmio, line;

	int line;

	int ret;



	if (!(early_uart_console.flags & CON_ENABLED))

		return 0;

	if (!device->port.membase && !device->port.iobase)

		return -ENODEV;



	/* Try to start the normal driver on a matching line.  */

	mmio = (port->iotype == UPIO_MEM);

	line = serial8250_start_console(port, device->options);

	line = serial8250_find_port(port);

	if (line < 0)

		printk("No ttyS device at %s 0x%lx for console\n",

			mmio ? "MMIO" : "I/O port",

			mmio ? port->mapbase :

			    (unsigned long) port->iobase);

		return -ENODEV;



	unregister_console(&early_uart_console);

	if (mmio)

		iounmap(port->membase);

	ret = update_console_cmdline("uart", 8250,

			     "ttyS", line, device->options);

	if (ret < 0)

		ret = update_console_cmdline("uart", 0,

				     "ttyS", line, device->options);



	return 0;

	return ret;

}

late_initcall(early_uart_console_switch);
 


early_param("earlycon", setup_early_serial8250_console);

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