diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/blackfin/Kconfig | 14 | ||||
| -rw-r--r-- | arch/blackfin/kernel/Makefile | 1 | ||||
| -rw-r--r-- | arch/blackfin/kernel/early_printk.c | 161 |
3 files changed, 176 insertions, 0 deletions
diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig index 26ebb0e8c431..cc789b988f3a 100644 --- a/arch/blackfin/Kconfig +++ b/arch/blackfin/Kconfig @@ -1164,6 +1164,20 @@ config DEBUG_BFIN_NO_KERN_HWTRACE Say Y here to disable hardware tracing in some known "jumpy" pieces of code so that the trace buffer will extend further back. +config EARLY_PRINTK + bool "Early printk" + default n + help + This option enables special console drivers which allow the kernel + to print messages very early in the bootup process. + + This is useful for kernel debugging when your machine crashes very + early before the console code is initialized. After enabling this + feature, you must add "earlyprintk=serial,uart0,57600" to the + command line (bootargs). It is safe to say Y here in all cases, as + all of this lives in the init section and is thrown away after the + kernel boots completely. + config DUAL_CORE_TEST_MODULE tristate "Dual Core Test Module" depends on (BF561) diff --git a/arch/blackfin/kernel/Makefile b/arch/blackfin/kernel/Makefile index 243883ec6de1..8aeb6066b19b 100644 --- a/arch/blackfin/kernel/Makefile +++ b/arch/blackfin/kernel/Makefile @@ -13,3 +13,4 @@ obj-$(CONFIG_MODULES) += module.o obj-$(CONFIG_BFIN_DMA_5XX) += bfin_dma_5xx.o obj-$(CONFIG_DUAL_CORE_TEST_MODULE) += dualcore_test.o obj-$(CONFIG_KGDB) += kgdb.o +obj-$(CONFIG_EARLY_PRINTK) += early_printk.o diff --git a/arch/blackfin/kernel/early_printk.c b/arch/blackfin/kernel/early_printk.c new file mode 100644 index 000000000000..9bf61706694f --- /dev/null +++ b/arch/blackfin/kernel/early_printk.c @@ -0,0 +1,161 @@ +/* + * File: arch/blackfin/kernel/early_printk.c + * Based on: arch/x86_64/kernel/early_printk.c + * Author: Robin Getz <rgetz@blackfin.uclinux.org + * + * Created: 14Aug2007 + * Description: allow a console to be used for early printk + * + * Modified: + * Copyright 2004-2007 Analog Devices Inc. + * + * Bugs: Enter bugs at http://blackfin.uclinux.org/ + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/serial_core.h> +#include <linux/console.h> +#include <linux/string.h> +#include <asm/blackfin.h> +#include <asm/irq_handler.h> +#include <asm/early_printk.h> + +#ifdef CONFIG_SERIAL_BFIN +extern struct console *bfin_earlyserial_init(unsigned int port, + unsigned int cflag); +#endif + +static struct console *early_console; + +/* Default console + * Port n == ttyBFn + * cflags == UART output modes + */ +#define DEFAULT_PORT 0 +#define DEFAULT_CFLAG CS8|B57600 + +#ifdef CONFIG_SERIAL_CORE +/* What should get here is "0,57600" */ +static struct console * __init earlyserial_init(char *buf) +{ + int baud, bit; + char parity; + unsigned int serial_port = DEFAULT_PORT; + unsigned int cflag = DEFAULT_CFLAG; + + serial_port = simple_strtoul(buf, &buf, 10); + buf++; + + cflag = 0; + baud = simple_strtoul(buf, &buf, 10); + switch (baud) { + case 1200: + cflag |= B1200; + break; + case 2400: + cflag |= B2400; + break; + case 4800: + cflag |= B4800; + break; + case 9600: + cflag |= B9600; + break; + case 19200: + cflag |= B19200; + break; + case 38400: + cflag |= B38400; + break; + case 115200: + cflag |= B115200; + break; + default: + cflag |= B57600; + } + + parity = buf[0]; + buf++; + switch (parity) { + case 'e': + cflag |= PARENB; + break; + case 'o': + cflag |= PARODD; + break; + } + + bit = simple_strtoul(buf, &buf, 10); + switch (bit) { + case 5: + cflag |= CS5; + break; + case 6: + cflag |= CS5; + break; + case 7: + cflag |= CS5; + break; + default: + cflag |= CS8; + } + +#ifdef CONFIG_SERIAL_BFIN + return bfin_earlyserial_init(serial_port, cflag); +#else + return NULL; +#endif + +} +#endif + +int __init setup_early_printk(char *buf) +{ + + /* Crashing in here would be really bad, so check both the var + and the pointer before we start using it + */ + if (!buf) + return 0; + + if (!*buf) + return 0; + + if (early_console != NULL) + return 0; + +#ifdef CONFIG_SERIAL_BFIN + /* Check for Blackfin Serial */ + if (!strncmp(buf, "serial,uart", 11)) { + buf += 11; + early_console = earlyserial_init(buf); + } +#endif +#ifdef CONFIG_FB + /* TODO: add framebuffer console support */ +#endif + + if (likely(early_console)) { + early_console->flags |= CON_BOOT; + + register_console(early_console); + printk(KERN_INFO "early printk enabled on %s%d\n", + early_console->name, + early_console->index); + } + + return 0; +} + +early_param("earlyprintk", setup_early_printk); |