android_kernel_xiaomi_sm8350/include/linux/serial_8250.h
Yinghai Lu 18a8bd949d 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: <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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:35 -07:00

68 lines
1.9 KiB
C

/*
* linux/include/linux/serial_8250.h
*
* Copyright (C) 2004 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#ifndef _LINUX_SERIAL_8250_H
#define _LINUX_SERIAL_8250_H
#include <linux/serial_core.h>
#include <linux/platform_device.h>
/*
* This is the platform device platform_data structure
*/
struct plat_serial8250_port {
unsigned long iobase; /* io base address */
void __iomem *membase; /* ioremap cookie or NULL */
unsigned long mapbase; /* resource base */
unsigned int irq; /* interrupt number */
unsigned int uartclk; /* UART clock rate */
unsigned char regshift; /* register shift */
unsigned char iotype; /* UPIO_* */
unsigned char hub6;
upf_t flags; /* UPF_* flags */
};
/*
* Allocate 8250 platform device IDs. Nothing is implied by
* the numbering here, except for the legacy entry being -1.
*/
enum {
PLAT8250_DEV_LEGACY = -1,
PLAT8250_DEV_PLATFORM,
PLAT8250_DEV_PLATFORM1,
PLAT8250_DEV_PLATFORM2,
PLAT8250_DEV_FOURPORT,
PLAT8250_DEV_ACCENT,
PLAT8250_DEV_BOCA,
PLAT8250_DEV_EXAR_ST16C554,
PLAT8250_DEV_HUB6,
PLAT8250_DEV_MCA,
PLAT8250_DEV_AU1X00,
};
/*
* This should be used by drivers which want to register
* their own 8250 ports without registering their own
* platform device. Using these will make your driver
* dependent on the 8250 driver.
*/
struct uart_port;
int serial8250_register_port(struct uart_port *);
void serial8250_unregister_port(int line);
void serial8250_suspend_port(int line);
void serial8250_resume_port(int line);
extern int serial8250_find_port(struct uart_port *p);
extern int serial8250_find_port_for_earlycon(void);
extern int setup_early_serial8250_console(char *cmdline);
#endif