android_kernel_xiaomi_sm8350/arch/sh64/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The disable_early_printk() call is obsolete with that patch, explicitly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

100 lines
2.3 KiB
C

/*
* arch/sh64/kernel/early_printk.c
*
* SH-5 Early SCIF console (cloned and hacked from sh implementation)
*
* Copyright (C) 2003, 2004 Paul Mundt <lethal@linux-sh.org>
* Copyright (C) 2002 M. R. Brown <mrbrown@0xd6.org>
*
* 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 <asm/io.h>
#include <asm/hardware.h>
#define SCIF_BASE_ADDR 0x01030000
#define SCIF_ADDR_SH5 PHYS_PERIPHERAL_BLOCK+SCIF_BASE_ADDR
/*
* Fixed virtual address where SCIF is mapped (should already be done
* in arch/sh64/kernel/head.S!).
*/
#define SCIF_REG 0xfa030000
enum {
SCIF_SCSMR2 = SCIF_REG + 0x00,
SCIF_SCBRR2 = SCIF_REG + 0x04,
SCIF_SCSCR2 = SCIF_REG + 0x08,
SCIF_SCFTDR2 = SCIF_REG + 0x0c,
SCIF_SCFSR2 = SCIF_REG + 0x10,
SCIF_SCFRDR2 = SCIF_REG + 0x14,
SCIF_SCFCR2 = SCIF_REG + 0x18,
SCIF_SCFDR2 = SCIF_REG + 0x1c,
SCIF_SCSPTR2 = SCIF_REG + 0x20,
SCIF_SCLSR2 = SCIF_REG + 0x24,
};
static void sh_console_putc(int c)
{
while (!(ctrl_inw(SCIF_SCFSR2) & 0x20))
cpu_relax();
ctrl_outb(c, SCIF_SCFTDR2);
ctrl_outw((ctrl_inw(SCIF_SCFSR2) & 0x9f), SCIF_SCFSR2);
if (c == '\n')
sh_console_putc('\r');
}
static void sh_console_flush(void)
{
ctrl_outw((ctrl_inw(SCIF_SCFSR2) & 0xbf), SCIF_SCFSR2);
while (!(ctrl_inw(SCIF_SCFSR2) & 0x40))
cpu_relax();
ctrl_outw((ctrl_inw(SCIF_SCFSR2) & 0xbf), SCIF_SCFSR2);
}
static void sh_console_write(struct console *con, const char *s, unsigned count)
{
while (count-- > 0)
sh_console_putc(*s++);
sh_console_flush();
}
static int __init sh_console_setup(struct console *con, char *options)
{
con->cflag = CREAD | HUPCL | CLOCAL | B19200 | CS8;
return 0;
}
static struct console sh_console = {
.name = "scifcon",
.write = sh_console_write,
.setup = sh_console_setup,
.flags = CON_PRINTBUFFER | CON_BOOT,
.index = -1,
};
void __init enable_early_printk(void)
{
ctrl_outb(0x2a, SCIF_SCBRR2); /* 19200bps */
ctrl_outw(0x04, SCIF_SCFCR2); /* Reset TFRST */
ctrl_outw(0x10, SCIF_SCFCR2); /* TTRG0=1 */
ctrl_outw(0, SCIF_SCSPTR2);
ctrl_outw(0x60, SCIF_SCFSR2);
ctrl_outw(0, SCIF_SCLSR2);
ctrl_outw(0x30, SCIF_SCSCR2);
register_console(&sh_console);
}