linux/arch/x86/kernel/early_printk.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/console.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/screen_info.h>
#include <linux/usb/ch9.h>
#include <linux/pci_regs.h>
#include <linux/pci_ids.h>
#include <linux/errno.h>
#include <linux/pgtable.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/fcntl.h>
#include <asm/setup.h>
#include <xen/hvc-console.h>
#include <asm/pci-direct.h>
#include <asm/fixmap.h>
#include <linux/usb/ehci_def.h>
#include <linux/usb/xhci-dbgp.h>
#include <asm/pci_x86.h>

/* Simple VGA output */
#define VGABASE …

static int max_ypos = …, max_xpos = …;
static int current_ypos = …, current_xpos;

static void early_vga_write(struct console *con, const char *str, unsigned n)
{ … }

static struct console early_vga_console = …;

/* Serial functions loosely based on a similar package from Klaus P. Gerlicher */

static unsigned long early_serial_base = …;  /* ttyS0 */

#define XMTRDY …

#define DLAB …

#define TXR …
#define RXR …
#define IER …
#define IIR …
#define FCR …
#define LCR …
#define MCR …
#define LSR …
#define MSR …
#define DLL …
#define DLH …

static unsigned int io_serial_in(unsigned long addr, int offset)
{ … }

static void io_serial_out(unsigned long addr, int offset, int value)
{ … }

static unsigned int (*serial_in)(unsigned long addr, int offset) = …;
static void (*serial_out)(unsigned long addr, int offset, int value) = …;

static int early_serial_putc(unsigned char ch)
{ … }

static void early_serial_write(struct console *con, const char *s, unsigned n)
{ … }

static __init void early_serial_hw_init(unsigned divisor)
{ … }

#define DEFAULT_BAUD …

static __init void early_serial_init(char *s)
{ … }

#ifdef CONFIG_PCI
static void mem32_serial_out(unsigned long addr, int offset, int value)
{ … }

static unsigned int mem32_serial_in(unsigned long addr, int offset)
{ … }

/*
 * early_pci_serial_init()
 *
 * This function is invoked when the early_printk param starts with "pciserial"
 * The rest of the param should be "[force],B:D.F,baud", where B, D & F describe
 * the location of a PCI device that must be a UART device. "force" is optional
 * and overrides the use of an UART device with a wrong PCI class code.
 */
static __init void early_pci_serial_init(char *s)
{ … }
#endif

static struct console early_serial_console = …;

static void early_console_register(struct console *con, int keep_early)
{ … }

static int __init setup_early_printk(char *buf)
{ … }

early_param(…);