linux/arch/sh/kernel/early_printk.c
Gerd Hoffmann 69331af79c Fixes and cleanups for earlyprintk aka boot console
The console subsystem already has an idea of a boot console, using the
CON_BOOT flag.  The implementation has some flaws though.  The major
problem is that presence of a boot console makes register_console() ignore
any other console devices (unless explicitly specified on the kernel
command line).

This patch fixes the console selection code to *not* consider a boot
console a full-featured one, so the first non-boot console registering will
become the default console instead.  This way the unregister call for the
boot console in the register_console() function actually triggers and the
handover from the boot console to the real console device works smoothly.
Added a printk for the handover, so you know which console device the
output goes to when the boot console stops printing messages.

The disable_early_printk() call is obsolete with that patch, explicitly
disabling the early console isn't needed any more as it works automagically
with that patch.

I've walked through the tree, dropped all disable_early_printk() instances
found below arch/ and tagged the consoles with CON_BOOT if needed.  The
code is tested on x86, sh (thanks to Paul) and mips (thanks to Ralf).

Changes to last version: Rediffed against -rc3, adapted to mips cleanups by
Ralf, fixed "udbg-immortal" cmd line arg on powerpc.

Signed-off-by: Gerd Hoffmann <kraxel@exsuse.de>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Andi Kleen <ak@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:04 -07:00

206 lines
4.5 KiB
C

/*
* arch/sh/kernel/early_printk.c
*
* Copyright (C) 1999, 2000 Niibe Yutaka
* Copyright (C) 2002 M. R. Brown
* Copyright (C) 2004 - 2006 Paul Mundt
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/console.h>
#include <linux/tty.h>
#include <linux/init.h>
#include <linux/io.h>
#ifdef CONFIG_SH_STANDARD_BIOS
#include <asm/sh_bios.h>
/*
* Print a string through the BIOS
*/
static void sh_console_write(struct console *co, const char *s,
unsigned count)
{
sh_bios_console_write(s, count);
}
/*
* Setup initial baud/bits/parity. We do two things here:
* - construct a cflag setting for the first rs_open()
* - initialize the serial port
* Return non-zero if we didn't find a serial port.
*/
static int __init sh_console_setup(struct console *co, char *options)
{
int cflag = CREAD | HUPCL | CLOCAL;
/*
* Now construct a cflag setting.
* TODO: this is a totally bogus cflag, as we have
* no idea what serial settings the BIOS is using, or
* even if its using the serial port at all.
*/
cflag |= B115200 | CS8 | /*no parity*/0;
co->cflag = cflag;
return 0;
}
static struct console bios_console = {
.name = "bios",
.write = sh_console_write,
.setup = sh_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
};
#endif
#ifdef CONFIG_EARLY_SCIF_CONSOLE
#include <linux/serial_core.h>
#include "../../../drivers/serial/sh-sci.h"
static struct uart_port scif_port = {
.mapbase = CONFIG_EARLY_SCIF_CONSOLE_PORT,
.membase = (char __iomem *)CONFIG_EARLY_SCIF_CONSOLE_PORT,
};
static void scif_sercon_putc(int c)
{
while (((sci_in(&scif_port, SCFDR) & 0x1f00 >> 8) == 16))
;
sci_out(&scif_port, SCxTDR, c);
sci_in(&scif_port, SCxSR);
sci_out(&scif_port, SCxSR, 0xf3 & ~(0x20 | 0x40));
while ((sci_in(&scif_port, SCxSR) & 0x40) == 0);
;
if (c == '\n')
scif_sercon_putc('\r');
}
static void scif_sercon_write(struct console *con, const char *s,
unsigned count)
{
while (count-- > 0)
scif_sercon_putc(*s++);
}
static int __init scif_sercon_setup(struct console *con, char *options)
{
con->cflag = CREAD | HUPCL | CLOCAL | B115200 | CS8;
return 0;
}
static struct console scif_console = {
.name = "sercon",
.write = scif_sercon_write,
.setup = scif_sercon_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
};
#if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_STANDARD_BIOS)
#define DEFAULT_BAUD 115200
/*
* Simple SCIF init, primarily aimed at SH7750 and other similar SH-4
* devices that aren't using sh-ipl+g.
*/
static void scif_sercon_init(char *s)
{
unsigned baud = DEFAULT_BAUD;
char *e;
if (*s == ',')
++s;
if (*s) {
/* ignore ioport/device name */
s += strcspn(s, ",");
if (*s == ',')
s++;
}
if (*s) {
baud = simple_strtoul(s, &e, 0);
if (baud == 0 || s == e)
baud = DEFAULT_BAUD;
}
ctrl_outw(0, scif_port.mapbase + 8);
ctrl_outw(0, scif_port.mapbase);
/* Set baud rate */
ctrl_outb((CONFIG_SH_PCLK_FREQ + 16 * baud) /
(32 * baud) - 1, scif_port.mapbase + 4);
ctrl_outw(12, scif_port.mapbase + 24);
ctrl_outw(8, scif_port.mapbase + 24);
ctrl_outw(0, scif_port.mapbase + 32);
ctrl_outw(0x60, scif_port.mapbase + 16);
ctrl_outw(0, scif_port.mapbase + 36);
ctrl_outw(0x30, scif_port.mapbase + 8);
}
#endif /* CONFIG_CPU_SH4 && !CONFIG_SH_STANDARD_BIOS */
#endif /* CONFIG_EARLY_SCIF_CONSOLE */
/*
* Setup a default console, if more than one is compiled in, rely on the
* earlyprintk= parsing to give priority.
*/
static struct console *early_console =
#ifdef CONFIG_SH_STANDARD_BIOS
&bios_console
#elif defined(CONFIG_EARLY_SCIF_CONSOLE)
&scif_console
#else
NULL
#endif
;
static int __initdata keep_early;
static int early_console_initialized;
int __init setup_early_printk(char *buf)
{
if (!buf)
return 0;
if (early_console_initialized)
return 0;
early_console_initialized = 1;
if (strstr(buf, "keep"))
keep_early = 1;
#ifdef CONFIG_SH_STANDARD_BIOS
if (!strncmp(buf, "bios", 4))
early_console = &bios_console;
#endif
#if defined(CONFIG_EARLY_SCIF_CONSOLE)
if (!strncmp(buf, "serial", 6)) {
early_console = &scif_console;
#if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_STANDARD_BIOS)
scif_sercon_init(buf + 6);
#endif
}
#endif
if (likely(early_console)) {
if (keep_early)
early_console->flags &= ~CON_BOOT;
else
early_console->flags |= CON_BOOT;
register_console(early_console);
}
return 0;
}
early_param("earlyprintk", setup_early_printk);