earlycon.c File Reference

x86: the early console, where printk() writes before the kernel's terminals exist. More...

#include <core/kargs.h>
#include <core/string.h>
#include <console/earlycon.h>

Go to the source code of this file.

Functions
int	earlycon_fb_available (void)
	Says whether the boot loader's framebuffer can be the early console.
int	earlycon_puts (char *s)
	Writes a string on the early console.
int	earlycon_putc (char c)
	Writes a character on the early console.
int	earlycon_on_screen (void)
	Says whether the early console writes on the screen, rather than on a serial port.
void	earlycon_init ()
	Sets up the early console at boot, before anything else.
void	earlycon_reinit ()
	Sets up the early console again, once the kernel's command line has been read, since it may choose another console (earlycon=).

Variables
static struct earlycon *	earlycon
struct earlycon	earlycon_uart
struct earlycon	earlycon_vga
struct earlycon	earlycon_fb

Detailed Description

x86: the early console, where printk() writes before the kernel's terminals exist.

It starts on the first serial port, and once the kernel's command line is read (earlycon_reinit()), moves to the boot loader's framebuffer if there is one. earlycon=ttyS0, earlycon=vga or earlycon=fb chooses it explicitly.

Definition in file earlycon.c.

Function Documentation

earlycon_fb_available()

int earlycon_fb_available ( void )

extern

Says whether the boot loader's framebuffer can be the early console.

Returns

1 if one was registered and has 32 bits per pixel, 0 if not

Definition at line 55 of file fb.c.

References earlycon_fb_available(), fb_depth, fb_paddr, and fb_size.

Referenced by earlycon_fb_available(), and earlycon_reinit().

earlycon_init()

void earlycon_init

(

void

)

Sets up the early console at boot, before anything else.

Definition at line 49 of file earlycon.c.

References earlycon_init(), earlycon_uart, and earlycon::init.

earlycon_on_screen()

int earlycon_on_screen

(

void

)

Says whether the early console writes on the screen, rather than on a serial port.

Returns

1 if it writes on the screen, 0 if not

Definition at line 43 of file earlycon.c.

References earlycon_on_screen(), and earlycon_uart.

earlycon_putc()

int earlycon_putc

(

char

c

)

Writes a character on the early console.

Parameters

c	the character

Returns

1 if it was written, 0 if not

Definition at line 34 of file earlycon.c.

References earlycon_putc(), and earlycon::putc.

earlycon_puts()

int earlycon_puts

(

char *

s

)

Writes a string on the early console.

Parameters

s	the string

Returns

how many characters were written

Definition at line 26 of file earlycon.c.

References earlycon_puts(), and earlycon::puts.

earlycon_reinit()

void earlycon_reinit

(

void

)

Sets up the early console again, once the kernel's command line has been read, since it may choose another console (earlycon=).

Definition at line 58 of file earlycon.c.

References earlycon_fb, earlycon_fb_available(), earlycon_reinit(), earlycon_uart, earlycon_vga, earlycon::init, kargs_get(), and NULL.

Variable Documentation

earlycon

struct earlycon* earlycon

static

Definition at line 15 of file earlycon.c.

earlycon_fb

struct earlycon earlycon_fb

extern

Definition at line 161 of file fb.c.

Referenced by earlycon_reinit().

earlycon_uart

struct earlycon earlycon_uart

extern

Definition at line 92 of file uart.c.

Referenced by earlycon_init(), earlycon_on_screen(), and earlycon_reinit().

earlycon_vga

struct earlycon earlycon_vga

extern

Definition at line 85 of file vga.c.

Referenced by earlycon_reinit().