[draft] Blackfin Early Printk implmentation

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The patch (for review - not inclusion - I will send to Bryan if no one has any 
major objections, and he can push it via git) implements early printk for the 
Blackfin architecture.

It also adds an early exception handler, so if an 
interrupt/exception/violation happens before the kernel enables it's 
interrupts (yes that does happen periodically, and it is a nice to have a 
debug feature to help , that we don't go back to the bootloaders exception 
processing table...

It also removes some of the crap that was trying to implement the same thing 
(poorly).

Before I send to Bryan "officially" - I thought I would see what others think.


---

 Documentation/kernel-parameters.txt |    3
 arch/blackfin/Kconfig               |   32 +--
 arch/blackfin/kernel/Makefile       |    1
 arch/blackfin/kernel/early_printk.c |  210 +++++++++++++++++++++
 arch/blackfin/kernel/setup.c        |   76 +++----
 arch/blackfin/mach-bf533/head.S     |  249 --------------------------
 arch/blackfin/mach-bf537/head.S     |    6
 arch/blackfin/mach-bf548/head.S     |    6
 arch/blackfin/mach-bf561/head.S     |    6
 arch/blackfin/mach-common/entry.S   |   45 ++++
 drivers/serial/bfin_5xx.c           |  130 ++++++++++---
 include/asm-blackfin/early_printk.h |   28 ++
 include/asm-blackfin/irq_handler.h  |   22 ++
 13 files changed, 485 insertions(+), 329 deletions(-)



Index: linux-2.6.x/include/asm-blackfin/early_printk.h
===================================================================
--- linux-2.6.x/include/asm-blackfin/early_printk.h	(revision 0)
+++ linux-2.6.x/include/asm-blackfin/early_printk.h	(revision 0)
@@ -0,0 +1,28 @@
+/*
+ * File:         include/asm-blackfin/early_printk.h
+ * Author:       Robin Getz <[email protected]
+ *
+ * Created:      14Aug2007
+ * Description:  function prototpyes 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.
+ */
+
+#ifdef CONFIG_EARLY_PRINTK
+extern int setup_early_printk(char *);
+#else
+#define setup_early_printk(fmt) do { } while (0)
+#endif /* CONFIG_EARLY_PRINTK */
Index: linux-2.6.x/include/asm-blackfin/irq_handler.h
===================================================================
--- linux-2.6.x/include/asm-blackfin/irq_handler.h	(revision 3568)
+++ linux-2.6.x/include/asm-blackfin/irq_handler.h	(working copy)
@@ -1,3 +1,24 @@
+/*
+ * File:         include/asm-blackfin/irq_handler.h
+ *
+ * Description:  function prototypes for interrupt handler routines
+ *
+ * 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.
+ */
+
 #ifndef _IRQ_HANDLER_H
 #define _IRQ_HANDLER_H
 
@@ -22,6 +43,7 @@
 asmlinkage void init_exception_buff(void);
 asmlinkage void trap_c(struct pt_regs *fp);
 asmlinkage void ex_replaceable(void);
+asmlinkage void early_trap(void);
 
 extern void *ex_table[];
 extern void return_from_exception(void);
Index: linux-2.6.x/Documentation/kernel-parameters.txt
===================================================================
--- linux-2.6.x/Documentation/kernel-parameters.txt	(revision 3568)
+++ linux-2.6.x/Documentation/kernel-parameters.txt	(working copy)
@@ -34,6 +34,7 @@
 	APIC	APIC support is enabled.
 	APM	Advanced Power Management support is enabled.
 	AX25	Appropriate AX.25 support is enabled.
+	BLACKFIN Blackfin architecture is enabled.
 	CD	Appropriate CD support is enabled.
 	DRM	Direct Rendering Management support is enabled.
 	EDD	BIOS Enhanced Disk Drive Services (EDD) is enabled
@@ -558,7 +559,7 @@
 
 	dtc3181e=	[HW,SCSI]
 
-	earlyprintk=	[IA-32,X86-64,SH]
+	earlyprintk=	[IA-32,X86-64,SH,BLACKFIN]
 			earlyprintk=vga
 			earlyprintk=serial[,ttySn[,baudrate]]
 
Index: linux-2.6.x/arch/blackfin/kernel/setup.c
===================================================================
--- linux-2.6.x/arch/blackfin/kernel/setup.c	(revision 3568)
+++ linux-2.6.x/arch/blackfin/kernel/setup.c	(working copy)
@@ -44,6 +44,7 @@
 #include <asm/blackfin.h>
 #include <asm/cplbinit.h>
 #include <asm/fixed_code.h>
+#include <asm/early_printk.h>
 
 u16 _bfin_swrst;
 
@@ -134,7 +135,6 @@
 	unsigned int memsize;
 	for (;;) {
 		if (c == ' ') {
-
 			if (!memcmp(to, "mem=", 4)) {
 				to += 4;
 				memsize = memparse(to, &to);
@@ -157,8 +157,10 @@
 							    1;
 					}
 				}
+			} else if (!memcmp(to, "earlyprintk=", 12)) {
+				to += 12;
+				setup_early_printk(to);
 			}
-
 		}
 		c = *(to++);
 		if (!c)
@@ -177,14 +179,7 @@
 #ifdef CONFIG_DUMMY_CONSOLE
 	conswitchp = &dummy_con;
 #endif
-	cclk = get_cclk();
-	sclk = get_sclk();
 
-#if !defined(CONFIG_BFIN_KERNEL_CLOCK)
-	if (ANOMALY_05000273 && cclk == sclk)
-		panic("ANOMALY 05000273, SCLK can not be same as CCLK");
-#endif
-
 #ifdef BF561_FAMILY
 	if (ANOMALY_05000266) {
 		bfin_read_IMDMA_D0_IRQ_STATUS();
@@ -192,29 +187,6 @@
 	}
 #endif
 
-#ifdef DEBUG_SERIAL_EARLY_INIT
-	bfin_console_init();	/* early console registration */
-	/* this give a chance to get printk() working before crash. */
-#endif
-
-	printk(KERN_INFO "Hardware Trace ");
-	if (bfin_read_TBUFCTL() & 0x1 )
-		printk("Active ");
-	else
-		printk("Off ");
-	if (bfin_read_TBUFCTL() & 0x2)
-		printk("and Enabled\n");
-	else
-	printk("and Disabled\n");
-
-
-#if defined(CONFIG_CHR_DEV_FLASH) || defined(CONFIG_BLK_DEV_FLASH)
-	/* we need to initialize the Flashrom device here since we might
-	 * do things with flash early on in the boot
-	 */
-	flash_probe();
-#endif
-
 #if defined(CONFIG_CMDLINE_BOOL)
 	strncpy(&command_line[0], CONFIG_CMDLINE, sizeof(command_line));
 	command_line[sizeof(command_line) - 1] = 0;
@@ -229,8 +201,36 @@
 	physical_mem_end = 0;
 	_ramend = CONFIG_MEM_SIZE * 1024 * 1024;
 
+	/* We parse command line early, to set memory limits and get
+	 * early_printk earlier than normal
+	 */
 	parse_cmdline_early(&command_line[0]);
 
+#if defined(CONFIG_CHR_DEV_FLASH) || defined(CONFIG_BLK_DEV_FLASH)
+	/* we need to initialize the Flashrom device here since we might
+	 * do things with flash early on in the boot
+	 */
+	flash_probe();
+#endif
+
+	cclk = get_cclk();
+	sclk = get_sclk();
+
+#if !defined(CONFIG_BFIN_KERNEL_CLOCK)
+	if (ANOMALY_05000273 && cclk < (sclk *2))
+		panic("ANOMALY 05000273: CCLK must be >= 2*SCLK ");
+#endif
+
+	printk(KERN_INFO "Hardware Trace ");
+	if (bfin_read_TBUFCTL() & 0x1 )
+		printk("Active ");
+	else
+		printk("Off ");
+	if (bfin_read_TBUFCTL() & 0x2)
+		printk("and Enabled\n");
+	else
+		printk("and Disabled\n");
+
 	if (physical_mem_end == 0)
 		physical_mem_end = _ramend;
 
@@ -298,13 +298,16 @@
 	 * 05000263 - Hardware loop corrupted when taking an ICPLB exception
 	 */
 #if (defined(CONFIG_DEBUG_HUNT_FOR_ZERO))
-	if (memory_end >= 56 * 1024 * 1024)
+	if (memory_end >= 56 * 1024 * 1024) {
 		memory_end = 56 * 1024 * 1024;
+		printk(KERN_NOTICE "Warning: limiting memory to %liMB due to hardware 
anomaly 05000263\n", memory_end >> 20);
+	}
 #else
-	if (memory_end >= 60 * 1024 * 1024)
+	if (memory_end >= 60 * 1024 * 1024) {
 		memory_end = 60 * 1024 * 1024;
+		printk(KERN_NOTICE "Warning: limiting memory to %liMB due to hardware 
anomaly 05000263\n", memory_end >> 20);
+	}
 #endif				/* CONFIG_DEBUG_HUNT_FOR_ZERO */
-	printk(KERN_NOTICE "Warning: limiting memory to %liMB due to hardware 
anomaly 05000263\n", memory_end >> 20);
 #endif				/* ANOMALY_05000263 */
 
 #if !defined(CONFIG_MTD_UCLINUX)
@@ -340,9 +343,6 @@
 	printk(KERN_INFO "Processor Speed: %lu MHz core clock and %lu Mhz System 
Clock\n",
 	       cclk / 1000000,  sclk / 1000000);
 
-	if (ANOMALY_05000273 && (cclk >> 1) <= sclk)
-		printk("\n\n\nANOMALY_05000273: CCLK must be >= 2*SCLK !!!\n\n\n");
-
 	printk(KERN_INFO "Board Memory: %ldMB\n", physical_mem_end >> 20);
 	printk(KERN_INFO "Kernel Managed Memory: %ldMB\n", _ramend >> 20);
 
Index: linux-2.6.x/arch/blackfin/kernel/early_printk.c
===================================================================
--- linux-2.6.x/arch/blackfin/kernel/early_printk.c	(revision 0)
+++ linux-2.6.x/arch/blackfin/kernel/early_printk.c	(revision 0)
@@ -0,0 +1,210 @@
+/*
+ * File:         arch/blackfin/kernel/early_printk.c
+ * Based on:     arch/x86_64/kernel/early_printk.c
+ * Author:       Robin Getz <[email protected]
+ *
+ * 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>
+
+extern struct console *bfin_earlyserial_init(unsigned int port,
+						unsigned int cflag);
+extern int bfin_earlyserial_disable(void);
+
+static struct console *early_console_initialized;
+
+/* Default console
+ * Port n == ttyBFn
+ * cflags == UART output modes
+ */
+#define DEFAULT_PORT 0
+#define DEFAULT_CFLAG CS8|B57600
+
+/*
+ * Set up a temporary Event Vector Table, so if something bad happens before
+ * the kernel is fully started, it doesn't vector off into somewhere we don't
+ * know
+ */
+
+asmlinkage void __init init_early_exception_vectors(void)
+{
+	/* cannot program in software:
+	 * evt0 - emulation (jtag)
+	 * evt1 - reset
+	 */
+	bfin_write_EVT2(early_trap);
+	bfin_write_EVT3(early_trap);
+	bfin_write_EVT5(early_trap);
+	bfin_write_EVT6(early_trap);
+	bfin_write_EVT7(early_trap);
+	bfin_write_EVT8(early_trap);
+	bfin_write_EVT9(early_trap);
+	bfin_write_EVT10(early_trap);
+	bfin_write_EVT11(early_trap);
+	bfin_write_EVT12(early_trap);
+	bfin_write_EVT13(early_trap);
+	bfin_write_EVT14(early_trap);
+	bfin_write_EVT15(early_trap);
+
+	/* Set all the return from interupt, exception, NMI to a known place
+	 * so if we do a RETI, RETX or RETN by mistake - we go somewhere known
+	 * Note - don't change RETS - we are in a subroutine, or
+	 * RETE - since it might screw up if emulator is attached
+	 */
+
+	asm("\tRETI = %0;\n"
+	    "\tRETX = %0;\n"
+	    "\tRETN = %0;\n"
+	    : : "p"(early_trap));
+}
+
+int __init setup_early_printk(char *buf)
+{
+	int baud, bit;
+	char parity;
+	unsigned int serial_port = DEFAULT_PORT;
+	unsigned int cflag = DEFAULT_CFLAG;
+
+	/* 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_initialized)
+		return 0;
+
+	if (!strncmp(buf, "serial", 6)) {
+		buf += 7;
+		if (!strncmp(buf, "ttyBF", 5)) {
+			buf += 5;
+			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;
+		}
+
+		early_console_initialized = bfin_earlyserial_init(serial_port,
+			cflag);
+	} else if (!strncmp(buf, "vga", 3)) {
+		/* TODO: add framebuffer console support? */
+	}
+
+	if (early_console_initialized)
+		printk(KERN_INFO "Early Printk Support Enabled on %s%d\n",
+			early_console_initialized->name,
+			early_console_initialized->index);
+
+	return 0;
+}
+
+int __init disable_early_printk(void)
+{
+	if (!early_console_initialized)
+		return 0;
+
+	printk(KERN_INFO "Unregister %s%d\n", early_console_initialized->name,
+		early_console_initialized->index);
+	unregister_console(early_console_initialized);
+	early_console_initialized = NULL;
+	return 0;
+}
+
+late_initcall(disable_early_printk);
+
+asmlinkage void __init early_trap_c(struct pt_regs *fp, void *retaddr)
+{
+	unsigned int serial_port = DEFAULT_PORT;
+	unsigned int cflag = DEFAULT_CFLAG;
+
+	/* This can happen before the uart is initialized, so initialize
+	 * the UART now
+	 */
+	if (!early_console_initialized) {
+		bfin_earlyserial_init(serial_port, cflag);
+	}
+
+	dump_bfin_regs(fp, retaddr);
+	dump_bfin_trace_buffer();
+
+	panic("Died early");
+}
Index: linux-2.6.x/arch/blackfin/kernel/Makefile
===================================================================
--- linux-2.6.x/arch/blackfin/kernel/Makefile	(revision 3568)
+++ linux-2.6.x/arch/blackfin/kernel/Makefile	(working copy)
@@ -15,3 +15,4 @@
 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
Index: linux-2.6.x/arch/blackfin/Kconfig
===================================================================
--- linux-2.6.x/arch/blackfin/Kconfig	(revision 3568)
+++ linux-2.6.x/arch/blackfin/Kconfig	(working copy)
@@ -1040,24 +1040,6 @@
 	  also relocates the irq_panic() function to L1 memory, (which is
 	  un-cached).
 
-config DEBUG_KERNEL_START
-	bool "Debug Kernel Startup"
-	depends on DEBUG_KERNEL
-	help
-	  Say Y here to put in an mini-execption handler before the kernel
-	  replaces the bootloader exception handler. This will stop kernels
-	  from dieing at startup with no visible error messages.
-
-config DEBUG_SERIAL_EARLY_INIT
-	bool "Initialize serial driver early"
-	default n
-	depends on SERIAL_BFIN
-	help
-	  Say Y here if you want to get kernel output early when kernel
-	  crashes before the normal console initialization. If this option
-	  is enable, console output will always go to the ttyBF0, no matter
-	  what kernel boot paramters you set.
-
 config DEBUG_HUNT_FOR_ZERO
 	bool "Catch NULL pointer reads/writes"
 	default y
@@ -1165,6 +1147,20 @@
 	  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,ttyBF0,57600" 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)
Index: linux-2.6.x/arch/blackfin/mach-bf533/head.S
===================================================================
--- linux-2.6.x/arch/blackfin/mach-bf533/head.S	(revision 3568)
+++ linux-2.6.x/arch/blackfin/mach-bf533/head.S	(working copy)
@@ -35,9 +35,6 @@
 #include <asm/mach-common/clocks.h>
 #include <asm/mach/mem_init.h>
 #endif
-#if CONFIG_DEBUG_KERNEL_START
-#include <asm/mach-common/def_LPBlackfin.h>
-#endif
 
 .global __rambase
 .global __ramstart
@@ -104,36 +101,6 @@
 	P0 = R1;
 	R0 = R1;
 
-#if CONFIG_DEBUG_KERNEL_START
-
-/*
- * Set up a temporary Event Vector Table, so if something bad happens before
- * the kernel is fully started, it doesn't vector off into the bootloaders
- * table
- */
-	P0.l = lo(EVT2);
-	P0.h = hi(EVT2);
-	P1.l = lo(EVT15);
-	P1.h = hi(EVT15);
-	P2.l = debug_kernel_start_trap;
-	P2.h = debug_kernel_start_trap;
-
-	RTS = P2;
-	RTI = P2;
-	RTX = P2;
-	RTN = P2;
-	RTE = P2;
-
-.Lfill_temp_vector_table:
-	[P0++] = P2;	/* Core Event Vector Table */
-	CC = P0 == P1;
-	if !CC JUMP .Lfill_temp_vector_table
-	P0 = r0;
-	P1 = r0;
-	P2 = r0;
-
-#endif
-
 	p0.h = hi(FIO_MASKA_C);
 	p0.l = lo(FIO_MASKA_C);
 	r0 = 0xFFFF(Z);
@@ -214,6 +181,12 @@
 	fp = sp;
 	usp = sp;
 
+#ifdef CONFIG_EARLY_PRINTK
+	SP += -12;
+	call _init_early_exception_vectors;
+	SP += 12;
+#endif
+
 	/* Put The Code for PLL Programming and SDRAM Programming in L1 ISRAM */
 	call _bf53x_relocate_l1_mem;
 #if CONFIG_BFIN_KERNEL_CLOCK
@@ -519,216 +492,6 @@
 	RTS;
 ENDPROC(_bfin_reset)
 
-#if CONFIG_DEBUG_KERNEL_START
-debug_kernel_start_trap:
-	/* Set up a temp stack in L1 - SDRAM might not be working  */
-	P0.L = lo(L1_DATA_A_START + 0x100);
-	P0.H = hi(L1_DATA_A_START + 0x100);
-	SP = P0;
-
-	/* Make sure the Clocks are the way I think they should be */
-	r0 = CONFIG_VCO_MULT & 63;       /* Load the VCO multiplier         */
-	r0 = r0 << 9;                    /* Shift it over,                  */
-	r1 = CLKIN_HALF;                 /* Do we need to divide CLKIN by 2?*/
-	r0 = r1 | r0;
-	r1 = PLL_BYPASS;                 /* Bypass the PLL?                 */
-	r1 = r1 << 8;                    /* Shift it over                   */
-	r0 = r1 | r0;                    /* add them all together           */
-
-	p0.h = hi(PLL_CTL);
-	p0.l = lo(PLL_CTL);              /* Load the address                */
-	cli r2;                          /* Disable interrupts              */
-	ssync;
-	w[p0] = r0.l;                    /* Set the value                   */
-	idle;                            /* Wait for the PLL to stablize    */
-	sti r2;                          /* Enable interrupts               */
-
-.Lcheck_again1:
-	p0.h = hi(PLL_STAT);
-	p0.l = lo(PLL_STAT);
-	R0 = W[P0](Z);
-	CC = BITTST(R0,5);
-	if ! CC jump .Lcheck_again1;
-
-	/* Configure SCLK & CCLK Dividers */
-	r0 = (CONFIG_CCLK_ACT_DIV | CONFIG_SCLK_DIV);
-	p0.h = hi(PLL_DIV);
-	p0.l = lo(PLL_DIV);
-	w[p0] = r0.l;
-	ssync;
-
-	/* Make sure UART is enabled - you can never be sure */
-
-/*
- * Setup for console. Argument comes from the menuconfig
- */
-
-#ifdef CONFIG_BAUD_9600
-#define CONSOLE_BAUD_RATE       9600
-#elif CONFIG_BAUD_19200
-#define CONSOLE_BAUD_RATE       19200
-#elif CONFIG_BAUD_38400
-#define CONSOLE_BAUD_RATE       38400
-#elif CONFIG_BAUD_57600
-#define CONSOLE_BAUD_RATE       57600
-#elif CONFIG_BAUD_115200
-#define CONSOLE_BAUD_RATE       115200
-#endif
-
-	p0.h = hi(UART_GCTL);
-	p0.l = lo(UART_GCTL);
-	r0 = 0x00(Z);
-	w[p0] = r0.L;   /* To Turn off UART clocks */
-	ssync;
-
-	p0.h = hi(UART_LCR);
-	p0.l = lo(UART_LCR);
-	r0 = 0x83(Z);
-	w[p0] = r0.L;   /* To enable DLL writes */
-	ssync;
-
-	R1 = (((CONFIG_CLKIN_HZ * CONFIG_VCO_MULT) / CONFIG_SCLK_DIV) / 
(CONSOLE_BAUD_RATE * 16));
-
-	p0.h = hi(UART_DLL);
-	p0.l = lo(UART_DLL);
-	r0 = 0xFF(Z);
-	r0 = R1 & R0;
-	w[p0] = r0.L;
-	ssync;
-
-	p0.h = hi(UART_DLH);
-	p0.l = lo(UART_DLH);
-	r1 >>= 8 ;
-	w[p0] = r1.L;
-	ssync;
-
-	p0.h = hi(UART_GCTL);
-	p0.l = lo(UART_GCTL);
-	r0 = 0x0(Z);
-	w[p0] = r0.L;   /* To enable UART clock */
-	ssync;
-
-	p0.h = hi(UART_LCR);
-	p0.l = lo(UART_LCR);
-	r0 = 0x03(Z);
-	w[p0] = r0.L;   /* To Turn on UART */
-	ssync;
-
-	p0.h = hi(UART_GCTL);
-	p0.l = lo(UART_GCTL);
-	r0 = 0x01(Z);
-	w[p0] = r0.L;   /* To Turn on UART Clocks */
-	ssync;
-
-	P0.h = hi(UART_THR);
-	P0.l = lo(UART_THR);
-	P1.h = hi(UART_LSR);
-	P1.l = lo(UART_LSR);
-
-	R0.L = 'K';
-	call .Lwait_char;
-	R0.L='e';
-	call .Lwait_char;
-	R0.L='r';
-	call .Lwait_char;
-	R0.L='n'
-	call .Lwait_char;
-	R0.L='e'
-	call .Lwait_char;
-	R0.L='l';
-	call .Lwait_char;
-	R0.L=' ';
-	call .Lwait_char;
-	R0.L='c';
-	call .Lwait_char;
-	R0.L='r';
-	call .Lwait_char;
-	R0.L='a';
-	call .Lwait_char;
-	R0.L='s';
-	call .Lwait_char;
-	R0.L='h';
-	call .Lwait_char;
-	R0.L='\r';
-	call .Lwait_char;
-	R0.L='\n';
-	call .Lwait_char;
-
-	R0.L='S';
-	call .Lwait_char;
-	R0.L='E';
-	call .Lwait_char;
-	R0.L='Q'
-	call .Lwait_char;
-	R0.L='S'
-	call .Lwait_char;
-	R0.L='T';
-	call .Lwait_char;
-	R0.L='A';
-	call .Lwait_char;
-	R0.L='T';
-	call .Lwait_char;
-	R0.L='=';
-	call .Lwait_char;
-	R2 = SEQSTAT;
-	call .Ldump_reg;
-
-	R0.L=' ';
-	call .Lwait_char;
-	R0.L='R';
-	call .Lwait_char;
-	R0.L='E'
-	call .Lwait_char;
-	R0.L='T'
-	call .Lwait_char;
-	R0.L='X';
-	call .Lwait_char;
-	R0.L='=';
-	call .Lwait_char;
-	R2 = RETX;
-	call .Ldump_reg;
-
-	R0.L='\r';
-	call .Lwait_char;
-	R0.L='\n';
-	call .Lwait_char;
-
-.Ldebug_kernel_start_trap_done:
-	JUMP    .Ldebug_kernel_start_trap_done;
-.Ldump_reg:
-	R3 = 32;
-	R4 = 0x0F;
-	R5 = ':';  /* one past 9 */
-
-.Ldump_reg2:
-	R0 = R2;
-	R3 += -4;
-	R0 >>>= R3;
-	R0 = R0 & R4;
-	R0 += 0x30;
-	CC = R0 <= R5;
-	if CC JUMP .Ldump_reg1;
-	R0 += 7;
-
-.Ldump_reg1:
-	R1.l = W[P1];
-	CC = BITTST(R1, 5);
-	if !CC JUMP .Ldump_reg1;
-	W[P0] = r0;
-
-	CC = R3 == 0;
-	if !CC JUMP .Ldump_reg2
-	RTS;
-
-.Lwait_char:
-	R1.l = W[P1];
-	CC = BITTST(R1, 5);
-	if !CC JUMP .Lwait_char;
-	W[P0] = r0;
-	RTS;
-
-#endif  /* CONFIG_DEBUG_KERNEL_START  */
-
 .data
 
 /*
Index: linux-2.6.x/arch/blackfin/mach-bf561/head.S
===================================================================
--- linux-2.6.x/arch/blackfin/mach-bf561/head.S	(revision 3568)
+++ linux-2.6.x/arch/blackfin/mach-bf561/head.S	(working copy)
@@ -169,6 +169,12 @@
 	fp = sp;
 	usp = sp;
 
+#ifdef CONFIG_EARLY_PRINTK
+	SP += -12;
+	call _init_early_exception_vectors;
+	SP += 12;
+#endif
+
 	/* Put The Code for PLL Programming and SDRAM Programming in L1 ISRAM */
 	call _bf53x_relocate_l1_mem;
 #if CONFIG_BFIN_KERNEL_CLOCK
Index: linux-2.6.x/arch/blackfin/mach-bf537/head.S
===================================================================
--- linux-2.6.x/arch/blackfin/mach-bf537/head.S	(revision 3568)
+++ linux-2.6.x/arch/blackfin/mach-bf537/head.S	(working copy)
@@ -224,6 +224,12 @@
 	fp = sp;
 	usp = sp;
 
+#ifdef CONFIG_EARLY_PRINTK
+	SP += -12;
+	call _init_early_exception_vectors;
+	SP += 12;
+#endif
+
 	/* Put The Code for PLL Programming and SDRAM Programming in L1 ISRAM */
 	call _bf53x_relocate_l1_mem;
 #if CONFIG_BFIN_KERNEL_CLOCK
Index: linux-2.6.x/arch/blackfin/mach-bf548/head.S
===================================================================
--- linux-2.6.x/arch/blackfin/mach-bf548/head.S	(revision 3568)
+++ linux-2.6.x/arch/blackfin/mach-bf548/head.S	(working copy)
@@ -125,6 +125,12 @@
 	FP = SP;
 	USP = SP;
 
+#ifdef CONFIG_EARLY_PRINTK
+	SP += -12;
+	call _init_early_exception_vectors;
+	SP += 12;
+#endif
+
 	/* Put The Code for PLL Programming and SDRAM Programming in L1 ISRAM */
 	call _bf53x_relocate_l1_mem;
 #if CONFIG_BFIN_KERNEL_CLOCK
Index: linux-2.6.x/arch/blackfin/mach-common/entry.S
===================================================================
--- linux-2.6.x/arch/blackfin/mach-common/entry.S	(revision 3568)
+++ linux-2.6.x/arch/blackfin/mach-common/entry.S	(working copy)
@@ -803,14 +803,57 @@
 .section .l1.data.B
 #endif
 ENTRY(_trace_buff_offset)
-        .long 0;
+	.long 0;
 ALIGN
 ENTRY(_software_trace_buff)
 	.rept ((1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN)*256);
 	.long 0
 	.endr
+#endif /* CONFIG_DEBUG_BFIN_HWTRACE_EXPAND */
+
+#ifdef CONFIG_EARLY_PRINTK
+#ifdef CONFIG_EXCPT_IRQ_SYSC_L1
+.section .l1.text
+#else
+.text
 #endif
 
+ENTRY(_early_trap)
+	SAVE_ALL_SYS
+	trace_buffer_stop(p0, r0);
+
+	/* Turn caches off, to ensure we don't get double exceptions */
+
+	P4.L = LO(IMEM_CONTROL);
+	P4.H = HI(IMEM_CONTROL);
+
+	R5 = [P4];              /* Control Register*/
+	BITCLR(R5,ENICPLB_P);
+	CLI R1;
+	SSYNC;          /* SSYNC required before writing to IMEM_CONTROL. */
+	.align 8;
+	[P4] = R5;
+	SSYNC;
+
+	P4.L = LO(DMEM_CONTROL);
+	P4.H = HI(DMEM_CONTROL);
+	R5 = [P4];
+	BITCLR(R5,ENDCPLB_P);
+	SSYNC;          /* SSYNC required before writing to DMEM_CONTROL. */
+	.align 8;
+	[P4] = R5;
+	SSYNC;
+	STI R1;
+
+	r0 = sp;        /* stack frame pt_regs pointer argument ==> r0 */
+	r1 = RETX;
+
+	SP += -12;
+	call _early_trap_c;
+	SP += 12;
+ENDPROC(_early_trap)
+#endif /* CONFIG_EARLY_PRINTK */
+
 /*
  * Put these in the kernel data section - that should always be covered by
  * a CPLB. This is needed to ensure we don't get double fault conditions
Index: linux-2.6.x/drivers/serial/bfin_5xx.c
===================================================================
--- linux-2.6.x/drivers/serial/bfin_5xx.c	(revision 3568)
+++ linux-2.6.x/drivers/serial/bfin_5xx.c	(working copy)
@@ -961,31 +961,7 @@
 }
 
 #ifdef CONFIG_SERIAL_BFIN_CONSOLE
-static void bfin_serial_console_putchar(struct uart_port *port, int ch)
-{
-	struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
-	while (!(UART_GET_LSR(uart) & THRE))
-		barrier();
-	UART_PUT_CHAR(uart, ch);
-	SSYNC();
-}
-
 /*
- * Interrupts are disabled on entering
- */
-static void
-bfin_serial_console_write(struct console *co, const char *s, unsigned int 
count)
-{
-	struct bfin_serial_port *uart = &bfin_serial_ports[co->index];
-	int flags = 0;
-
-	spin_lock_irqsave(&uart->port.lock, flags);
-	uart_console_write(&uart->port, s, count, bfin_serial_console_putchar);
-	spin_unlock_irqrestore(&uart->port.lock, flags);
-
-}
-
-/*
  * If the port was already initialised (eg, by a boot loader),
  * try to determine the current setup.
  */
@@ -1037,19 +1013,25 @@
 	}
 	pr_debug("%s:baud = %d, parity = %c, bits= %d\n", __FUNCTION__, *baud, 
*parity, *bits);
 }
+#endif
 
+#if defined (CONFIG_SERIAL_BFIN_CONSOLE) || defined (CONFIG_EARLY_PRINTK)
+static struct uart_driver bfin_serial_reg;
+
 static int __init
 bfin_serial_console_setup(struct console *co, char *options)
 {
 	struct bfin_serial_port *uart;
+# ifdef CONFIG_SERIAL_BFIN_CONSOLE
 	int baud = 57600;
 	int bits = 8;
 	int parity = 'n';
-#ifdef CONFIG_SERIAL_BFIN_CTSRTS
+#  ifdef CONFIG_SERIAL_BFIN_CTSRTS
 	int flow = 'r';
-#else
+#  else
 	int flow = 'n';
-#endif
+#  endif
+# endif
 
 	/*
 	 * Check whether an invalid uart number has been specified, and
@@ -1060,15 +1042,45 @@
 		co->index = 0;
 	uart = &bfin_serial_ports[co->index];
 
+# ifdef CONFIG_SERIAL_BFIN_CONSOLE
 	if (options)
 		uart_parse_options(options, &baud, &parity, &bits, &flow);
 	else
 		bfin_serial_console_get_options(uart, &baud, &parity, &bits);
 
 	return uart_set_options(&uart->port, co, baud, parity, bits, flow);
+# else
+	return 0;
+# endif
 }
+#endif /* defined (CONFIG_SERIAL_BFIN_CONSOLE) ||
+				 defined (CONFIG_EARLY_PRINTK) */
 
-static struct uart_driver bfin_serial_reg;
+#ifdef CONFIG_SERIAL_BFIN_CONSOLE
+static void bfin_serial_console_putchar(struct uart_port *port, int ch)
+{
+	struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
+	while (!(UART_GET_LSR(uart) & THRE))
+		barrier();
+	UART_PUT_CHAR(uart, ch);
+	SSYNC();
+}
+
+/*
+ * Interrupts are disabled on entering
+ */
+static void
+bfin_serial_console_write(struct console *co, const char *s, unsigned int 
count)
+{
+	struct bfin_serial_port *uart = &bfin_serial_ports[co->index];
+	int flags = 0;
+
+	spin_lock_irqsave(&uart->port.lock, flags);
+	uart_console_write(&uart->port, s, count, bfin_serial_console_putchar);
+	spin_unlock_irqrestore(&uart->port.lock, flags);
+
+}
+
 static struct console bfin_serial_console = {
 	.name		= BFIN_SERIAL_NAME,
 	.write		= bfin_serial_console_write,
@@ -1094,8 +1106,70 @@
 #define BFIN_SERIAL_CONSOLE	&bfin_serial_console
 #else
 #define BFIN_SERIAL_CONSOLE	NULL
+#endif /* CONFIG_SERIAL_BFIN_CONSOLE */
+
+
+#ifdef CONFIG_EARLY_PRINTK
+static __init void early_serial_putc(struct uart_port *port, int ch)
+{
+	unsigned timeout = 0xffff;
+	struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
+
+	while ((!(UART_GET_LSR(uart) & THRE)) && --timeout)
+		cpu_relax();
+	UART_PUT_CHAR(uart, ch);
+}
+
+static __init void early_serial_write(struct console *con, const char *s,
+					unsigned int n)
+{
+	struct bfin_serial_port *uart = &bfin_serial_ports[con->index];
+	unsigned int i;
+
+	for (i = 0; i < n; i++, s++) {
+		if (*s == '\n')
+			early_serial_putc(&uart->port, '\r');
+		early_serial_putc(&uart->port, *s);
+	}
+}
+
+static struct __init console bfin_early_serial_console = {
+	.name = "early_ttyBF",
+	.write = early_serial_write,
+	.device = uart_console_device,
+	.flags = CON_BOOT,
+	.setup = bfin_serial_console_setup,
+	.index = -1,
+	.data  = &bfin_serial_reg,
+};
+
+struct console __init *bfin_earlyserial_init(unsigned int port,
+						unsigned int cflag)
+{
+	struct bfin_serial_port *uart;
+	struct ktermios t;
+
+	if (port == -1 || port >= nr_ports)
+		port = 0;
+	bfin_serial_init_ports();
+	bfin_early_serial_console.index = port;
+	register_console(&bfin_early_serial_console);
+#ifdef CONFIG_KGDB_UART
+	kgdb_entry_state = 0;
+	init_kgdb_uart();
 #endif
+	uart = &bfin_serial_ports[port];
+	t.c_cflag = cflag;
+	t.c_iflag = 0;
+	t.c_oflag = 0;
+	t.c_lflag = ICANON;
+	t.c_line = port;
+	bfin_serial_set_termios(&uart->port, &t, &t);
+	return &bfin_early_serial_console;
+}
 
+#endif /* CONFIG_SERIAL_BFIN_CONSOLE */
+
 static struct uart_driver bfin_serial_reg = {
 	.owner			= THIS_MODULE,
 	.driver_name		= "bfin-uart",
-
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