0ae53640b5
This allows debugging of problems which happen eary in the kernel boot process (after bootargs are parsed, but before serial subsystem is fully initialized) Signed-off-by: Robin Getz <robin.getz@analog.com> Signed-off-by: Bryan Wu <bryan.wu@analog.com>
162 lines
3.2 KiB
C
162 lines
3.2 KiB
C
/*
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* File: arch/blackfin/kernel/early_printk.c
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* Based on: arch/x86_64/kernel/early_printk.c
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* Author: Robin Getz <rgetz@blackfin.uclinux.org
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*
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* Created: 14Aug2007
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* Description: allow a console to be used for early printk
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*
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* Modified:
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* Copyright 2004-2007 Analog Devices Inc.
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*
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* Bugs: Enter bugs at http://blackfin.uclinux.org/
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/serial_core.h>
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#include <linux/console.h>
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#include <linux/string.h>
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#include <asm/blackfin.h>
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#include <asm/irq_handler.h>
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#include <asm/early_printk.h>
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#ifdef CONFIG_SERIAL_BFIN
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extern struct console *bfin_earlyserial_init(unsigned int port,
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unsigned int cflag);
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#endif
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static struct console *early_console;
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/* Default console
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* Port n == ttyBFn
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* cflags == UART output modes
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*/
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#define DEFAULT_PORT 0
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#define DEFAULT_CFLAG CS8|B57600
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#ifdef CONFIG_SERIAL_CORE
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/* What should get here is "0,57600" */
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static struct console * __init earlyserial_init(char *buf)
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{
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int baud, bit;
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char parity;
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unsigned int serial_port = DEFAULT_PORT;
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unsigned int cflag = DEFAULT_CFLAG;
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serial_port = simple_strtoul(buf, &buf, 10);
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buf++;
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cflag = 0;
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baud = simple_strtoul(buf, &buf, 10);
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switch (baud) {
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case 1200:
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cflag |= B1200;
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break;
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case 2400:
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cflag |= B2400;
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break;
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case 4800:
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cflag |= B4800;
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break;
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case 9600:
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cflag |= B9600;
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break;
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case 19200:
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cflag |= B19200;
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break;
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case 38400:
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cflag |= B38400;
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break;
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case 115200:
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cflag |= B115200;
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break;
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default:
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cflag |= B57600;
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}
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parity = buf[0];
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buf++;
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switch (parity) {
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case 'e':
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cflag |= PARENB;
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break;
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case 'o':
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cflag |= PARODD;
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break;
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}
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bit = simple_strtoul(buf, &buf, 10);
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switch (bit) {
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case 5:
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cflag |= CS5;
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break;
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case 6:
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cflag |= CS5;
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break;
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case 7:
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cflag |= CS5;
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break;
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default:
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cflag |= CS8;
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}
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#ifdef CONFIG_SERIAL_BFIN
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return bfin_earlyserial_init(serial_port, cflag);
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#else
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return NULL;
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#endif
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}
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#endif
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int __init setup_early_printk(char *buf)
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{
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/* Crashing in here would be really bad, so check both the var
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and the pointer before we start using it
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*/
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if (!buf)
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return 0;
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if (!*buf)
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return 0;
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if (early_console != NULL)
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return 0;
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#ifdef CONFIG_SERIAL_BFIN
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/* Check for Blackfin Serial */
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if (!strncmp(buf, "serial,uart", 11)) {
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buf += 11;
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early_console = earlyserial_init(buf);
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}
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#endif
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#ifdef CONFIG_FB
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/* TODO: add framebuffer console support */
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#endif
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if (likely(early_console)) {
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early_console->flags |= CON_BOOT;
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register_console(early_console);
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printk(KERN_INFO "early printk enabled on %s%d\n",
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early_console->name,
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early_console->index);
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}
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return 0;
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}
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early_param("earlyprintk", setup_early_printk);
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