Initial revision

1 files changed, 745 insertions, 0 deletions

diff --git a/board/w7o/post1.S b/board/w7o/post1.S
new file mode 100644
index 0000000..d510cca
--- /dev/null
+++ b/board/w7o/post1.S
@@ -0,0 +1,745 @@
+/*
+ * (C) Copyright 2001
+ * Bill Hunter, Wave 7 Optics, william.hunter@mediaone.net
+ *  and
+ * Erik Theisen, Wave 7 Optics, etheisen@mindspring.com
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+/*
+ * Description:
+ *	Routine to exercise memory for the bringing up of our boards.
+ */
+#include <config.h>
+#include <ppc4xx.h>
+
+#define _LINUX_CONFIG_H 1       /* avoid reading Linux autoconf.h file  */
+
+#include <ppc_asm.tmpl>
+#include <ppc_defs.h>
+
+#include <asm/cache.h>
+#include <asm/mmu.h>
+
+#include <watchdog.h>
+
+#include "errors.h"
+
+#define _ASMLANGUAGE
+
+	.globl	test_sdram
+	.globl	test_led
+	.globl	log_stat
+	.globl	log_warn
+	.globl	log_err
+	.globl  temp_uart_init
+	.globl  post_puts
+	.globl  disp_hex
+
+/*****************************************************
+*******   Text Strings for low level printing   ******
+*******          In section got2               *******
+*****************************************************/
+
+/*
+ * Define the text strings for errors and warnings.
+ * Switch to .data section.
+ */
+	.section ".data"
+err_str: 	.asciz "*** POST ERROR   = "
+warn_str:	.asciz "*** POST WARNING = "
+end_str:  .asciz "\r\n"
+
+/*
+ * Enter the labels in Global Entry Table (GOT).
+ * Switch to .got2 section.
+ */
+	START_GOT
+	GOT_ENTRY(err_str)
+	GOT_ENTRY(warn_str)
+	GOT_ENTRY(end_str)
+	END_GOT
+
+/*
+ * Switch  back to .text section.
+ */
+	.text
+
+/****************************************
+ ****************************************
+ ********    LED register test   ********
+ ****************************************
+ ***************************************/
+test_led:
+	/* save the return info on stack */
+	mflr	r0			/* Get link register */
+	stwu	r1, -12(r1)		/* Save back chain and move SP */
+	stw	r0, +16(r1)		/* Save link register */
+	stw	r4, +8(r1)		/* save R4 */
+
+	WATCHDOG_RESET        		/* Reset the watchdog */
+
+	addi    r3, 0, ERR_FF		/* first test value is ffff */
+	addi	r4, r3, 0		/* save copy of pattern */
+	bl	set_led			/* store first test value */
+	bl	get_led			/* read it back */
+	xor.	r4, r4, r3		/* compare to original */
+#if defined(CONFIG_W7OLMC)
+	andi.   r4, r4, 0x00ff		/* lmc has 8 bits */
+#else
+	andi.   r4, r4, 0xffff		/* lmg has 16 bits */
+#endif
+	beq     LED2			/* next test */
+	addi    r3, 0, ERR_LED		/* error code = 1 */
+	bl	log_err			/* display error and halt */
+LED2:	addi    r3, 0, ERR_00		/* 2nd test value is 0000 */
+	addi	r4, r3, 0		/* save copy of pattern */
+	bl	set_led			/* store first test value */
+	bl	get_led			/* read it back */
+	xor.	r4, r4, r3		/* compare to original */
+#if defined(CONFIG_W7OLMC)
+	andi.   r4, r4, 0x00ff		/* lmc has 8 bits */
+#else
+	andi.   r4, r4, 0xffff		/* lmg has 16 bits */
+#endif
+	beq     LED3			/* next test */
+	addi    r3, 0, ERR_LED		/* error code = 1 */
+	bl	log_err			/* display error and halt */
+
+LED3:	/* restore stack and return */
+	lwz	r0, +16(r1)		/* Get saved link register */
+	mtlr	r0			/* Restore link register */
+	lwz	r4, +8(r1)		/* restore r4 */
+	addi	r1, r1, +12		/* Remove frame from stack */
+	blr				/* Return to calling function */
+
+/****************************************
+ ****************************************
+ ********     SDRAM TESTS        ********
+ ****************************************
+ ***************************************/
+test_sdram:
+	/* called with mem size in r3 */
+	/* save the return info on stack */
+	mflr	r0			/* Get link register */
+	stwu	r1, -16(r1)		/* Save back chain and move SP */
+	stw	r0, +20(r1)		/* Save link register */
+	stmw	r30, +8(r1)		/* save R30,R31 */
+					/* r30 is log2(mem size) */
+					/* r31 is mem size */
+
+	/* take log2 of total mem size */
+	addi	r31, r3, 0		/* save total mem size */
+	addi	r30, 0, 0		/* clear r30 */
+l2_loop:
+	srwi.	r31, r31, 1		/* shift right 1 */
+	addi	r30, r30, 1		/* count shifts */
+	bne	l2_loop			/* loop till done */
+	addi	r30, r30, -1		/* correct for over count */
+	addi	r31, r3, 0		/* save original size */
+
+	/* now kick the dog and test the mem */
+	WATCHDOG_RESET        		/* Reset the watchdog */
+	bl	Data_Buster		/* test crossed/shorted data lines */
+	addi	r3, r30, 0		/* get log2(memsize) */
+	addi	r4, r31, 0		/* get memsize */
+	bl	Ghost_Buster		/* test crossed/shorted addr lines */
+	addi	r3, r31, 0		/* get mem size */
+	bl	Bit_Buster		/* check for bad internal bits */
+
+	/* restore stack and return */
+	lmw	r30, +8(r1)		/* Restore r30, r31 */
+	lwz	r0, +20(r1)		/* Get saved link register */
+	mtlr	r0			/* Restore link register */
+	addi	r1, r1, +16		/* Remove frame from stack */
+	blr				/* Return to calling function */
+
+
+/****************************************
+ ********  sdram data bus test   ********
+ ***************************************/
+Data_Buster:
+	/* save the return info on stack */
+	mflr	r0			/* Get link register */
+	stwu	r1, -24(r1)		/* Save back chain and move SP */
+	stw	r0, +28(r1)		/* Save link register */
+	stmw	r28, 8(r1)		/* save r28 - r31 on stack */
+					/* r31 i/o register */
+					/* r30 sdram base address */
+					/* r29 5555 syndrom */
+					/* r28 aaaa syndrom */
+
+	/* set up led register for this test */
+	addi    r3, 0, ERR_RAMG		/* set led code to 1 */
+	bl	log_stat		/* store test value */
+	/* now test the dram data bus */
+	xor	r30, r30, r30		/* load r30 with base addr of sdram */
+	addis	r31, 0, 0x5555		/* load r31 with test value */
+	ori	r31, r31, 0x5555
+	stw	r31,0(r30)		/* sto the value */
+	lwz	r29,0(r30)		/* read it back */
+	xor	r29,r31,r29		/* compare it to original */
+	addis	r31, 0, 0xaaaa		/* load r31 with test value */
+	ori	r31, r31, 0xaaaa
+	stw	r31,0(r30)		/* sto the value */
+	lwz	r28,0(r30)		/* read it back */
+	xor	r28,r31,r28		/* compare it to original */
+	or	r3,r28,r29		/* or together both error terms */
+	/*
+	 * Now that we have the error bits,
+	 * we have to decide which part they are in.
+	 */
+	bl	get_idx			/* r5 is now index to error */
+	addi	r3, r3, ERR_RAMG
+	cmpwi	r3, ERR_RAMG		/* check for errors */
+	beq	db_done			/* skip if no errors */
+	bl	log_err			/* log the error */
+
+db_done:
+	lmw	r28, 8(r1)		/* restore r28 - r31 from stack */
+	lwz	r0, +28(r1)		/* Get saved link register */
+	addi	r1, r1, +24		/* Remove frame from stack */
+	mtlr	r0			/* Restore link register */
+	blr				/* Return to calling function */
+
+
+/****************************************************
+ ********  test for address ghosting in dram ********
+ ***************************************************/
+
+Ghost_Buster:
+	/* save the return info on stack */
+	mflr	r0			/* Get link register */
+	stwu	r1, -36(r1)		/* Save back chain and move SP */
+	stw	r0, +40(r1)		/* Save link register */
+	stmw	r25, 8(r1)		/* save r25 - r31 on stack */
+					/* r31 = scratch register */
+					/* r30 is main referance loop counter,
+					   0 to 23 */
+					/* r29 is ghost loop count, 0 to 22 */
+					/* r28 is referance address */
+					/* r27 is ghost address */
+					/* r26 is log2 (mem size) =
+					     number of byte addr bits */
+					/* r25 is mem size */
+
+	/* save the log2(mem size) and mem size */
+	addi	r26, r3, 0		/* r26 is number of byte addr bits */
+	addi	r25, r4, 0		/* r25 is mem size in bytes */
+
+	/* set the leds for address ghost test */
+	addi	r3, 0, ERR_ADDG
+	bl	set_led
+
+	/* first fill memory with zeros */
+	srwi	r31, r25, 2		/* convert bytes to longs */
+	mtctr	r31			/* setup byte counter */
+	addi	r28, 0, 0		/* start at address at 0 */
+	addi	r31, 0, 0		/* data value = 0 */
+clr_loop:
+	stw	r31, 0(r28)		/* Store zero value */
+	addi	r28, r28, 4		/* Increment to next word */
+	andi.	r27, r28, 0xffff	/* check for 2^16 loops */
+	bne	clr_skip		/* if not there, then skip */
+	WATCHDOG_RESET   		/* kick the dog every now and then */
+clr_skip:
+	bdnz	clr_loop		/* Round and round... */
+
+	/* now do main test */
+	addi	r30, 0, 0		/* start referance counter at 0 */
+outside:
+	/*
+	 * Calculate the referance address
+	 *   the referance address is calculated by setting the (r30-1)
+	 *   bit of the base address
+	 * when r30=0, the referance address is the base address.
+	 * thus the sequence 0,1,2,4,8,..,2^(n-1)
+	 * setting the bit is done with the following shift functions.
+	 */
+	WATCHDOG_RESET   		/* Reset the watchdog */
+
+	addi	r31, 0, 1		/* r31 = 1 */
+	slw	r28, r31, r30		/* set bit coresponding to loop cnt */
+	srwi	r28, r28, 1		/* then shift it right one so  */
+					/*   we start at location 0 */
+	/* fill referance address with Fs */
+	addi	r31, 0, 0x00ff		/* r31 = one byte of set bits */
+	stb     r31,0(r28)		/* save ff in referance address */
+
+        /* ghost (inner) loop, now check all posible ghosted addresses */
+	addi	r29, 0, 0		/* start ghosted loop counter at 0 */
+inside:
+	/*
+	 * Calculate the ghost address by flipping one
+	 *  bit of referance address.  This gives the
+	 *  sequence 1,2,4,8,...,2^(n-1)
+	 */
+	addi	r31, 0, 1		/* r31 = 1 */
+	slw     r27, r31, r29		/* set  bit coresponding to loop cnt */
+	xor	r27, r28, r27		/* ghost address = ref addr with
+					     bit flipped*/
+
+	/* now check for ghosting */
+	lbz     r31,0(r27)		/* get content of ghost addr */
+	cmpwi   r31, 0			/* compare read value to 0 */
+	bne	Casper			/*   we found a ghost! */
+
+	/* now close ghost ( inner ) loop */
+	addi 	r29, r29, 1		/* increment inner loop counter */
+	cmpw 	r29, r26		/* check for last inner loop */
+	blt		inside		/* do more inner loops */
+
+	/* now close referance ( outer ) loop */
+	addi 	r31, 0, 0 		/* r31 = zero */
+	stb	r31, 0(28)		/* zero out the altered address loc. */
+	/*
+	 * Increment and check for end, count is zero based.
+	 * With the ble, this gives us one more loops than
+	 * address bits for sequence 0,1,2,4,8,...2^(n-1)
+	*/
+	addi 	r30, r30, 1		/* increment outer loop counter */
+	cmpw 	r30, r26		/* check for last inner loop */
+	ble	outside			/* do more outer loops */
+
+	/* were done, lets go home */
+	b	gb_done
+Casper:					/* we found a ghost !! */
+	addi	r3, 0, ERR_ADDF		/* get indexed error message */
+	bl	log_err			/* log error led error code */
+gb_done: /*  pack your bags, and go home */
+        lmw     r25, 8(r1)              /* restore r25 - r31 from stack */
+        lwz     r0, +40(r1)             /* Get saved link register */
+        addi    r1, r1, +36             /* Remove frame from stack */
+        mtlr    r0                      /* Restore link register */
+        blr                             /* Return to calling function */
+
+/****************************************************
+ ********      SDRAM data fill tests       **********
+ ***************************************************/
+Bit_Buster:
+	/* called with mem size in r3 */
+	/* save the return info on stack */
+	mflr	r0			/* Get link register */
+	stwu	r1, -16(r1)		/* Save back chain and move SP */
+	stw	r0, +20(r1)		/* Save link register */
+	stw	r4, +8(r1)		/* save R4 */
+	stw	r5, +12(r1)		/* save r5 */
+
+	addis	r5, r3, 0		/* save mem size */
+
+	/* Test 55555555 */
+	addi	r3, 0, ERR_R55G		/* set up error code in case we fail */
+	bl	log_stat		/* store test value */
+	addis	r4, 0, 0x5555
+	ori	r4, r4, 0x5555
+	bl	fill_test
+
+	/* Test aaaaaaaa  */
+	addi	r3, 0, ERR_RAAG		/* set up error code in case we fail */
+	bl	log_stat		/* store test value */
+	addis	r4, 0, 0xAAAA
+	ori	r4, r4, 0xAAAA
+	bl	fill_test
+
+	/* Test 00000000  */
+	addi	r3, 0, ERR_R00G		/* set up error code in case we fail */
+	bl	log_stat		/* store test value */
+	addis	r4, 0, 0
+	ori	r4, r4, 0
+	bl	fill_test
+
+	/* restore stack and return */
+	lwz	r5, +12(r1)		/* restore r4 */
+	lwz	r4, +8(r1)		/* restore r4 */
+	lwz	r0, +20(r1)		/* Get saved link register */
+	addi	r1, r1, +16		/* Remove frame from stack */
+	mtlr	r0			/* Restore link register */
+	blr				/* Return to calling function */
+
+
+
+/****************************************************
+ ********             fill test              ********
+ ***************************************************/
+/*	tests memory by filling with value, and reading back */
+/*	r5 = Size of memory in bytes */
+/*	r4 = Value to write */
+/*	r3 = Error code */
+fill_test:
+        mflr    r0                      /* Get link register */
+        stwu    r1, -32(r1)             /* Save back chain and move SP */
+        stw     r0, +36(r1)             /* Save link register */
+        stmw    r27, 8(r1)              /* save r27 - r31 on stack */
+                                        /* r31 - scratch register */
+                                        /* r30 - memory address */
+	mr	r27, r3
+	mr	r28, r4
+	mr	r29, r5
+
+	WATCHDOG_RESET   		/* Reset the watchdog */
+
+	/* first fill memory with Value */
+	srawi	r31, r29, 2		/* convert bytes to longs */
+	mtctr	r31			/* setup counter */
+	addi	r30, 0, 0		/* Make r30 = addr 0 */
+ft_0:	stw	r28, 0(r30)		/* Store value */
+	addi	r30, r30, 4		/* Increment to next word */
+	andi.	r31, r30, 0xffff	/* check for 2^16 loops */
+	bne	ft_0a			/* if not there, then skip */
+	WATCHDOG_RESET   		/* kick the dog every now and then */
+ft_0a:	bdnz	ft_0			/* Round and round... */
+
+	WATCHDOG_RESET   		/* Reset the watchdog */
+
+	/* Now confirm Value is in memory */
+	srawi	r31, r29, 2		/* convert bytes to longs */
+	mtctr	r31			/* setup counter */
+	addi	r30, 0, 0		/* Make r30 = addr 0 */
+ft_1:	lwz	r31, 0(r30)		/* get value from memory */
+        xor.	r31, r31, r28		/* Writen = Read ? */
+        bne	ft_err			/* If bad, than halt */
+	addi	r30, r30, 4		/* Increment to next word */
+	andi.	r31, r30, 0xffff	/* check for 2^16 loops*/
+	bne	ft_1a			/* if not there, then skip */
+	WATCHDOG_RESET			/* kick the dog every now and then */
+ft_1a:	bdnz	ft_1			/* Round and round... */
+
+	WATCHDOG_RESET   		/* Reset the watchdog */
+
+	b	fill_done		/* restore and return */
+
+ft_err:	addi	r29, r27, 0		/* save current led code */
+	addi	r27, r31, 0		/* get pattern in r27 */
+	bl	get_idx			/* get index from r27 */
+	add	r27, r27, r29		/* add index to old led code */
+	bl	log_err			/* output led err code, halt CPU */
+
+fill_done:
+        lmw     r27, 8(r1)              /* restore r27 - r31 from stack */
+        lwz     r0, +36(r1)             /* Get saved link register */
+        addi    r1, r1, +32             /* Remove frame from stack */
+        mtlr    r0                      /* Restore link register */
+        blr                             /* Return to calling function */
+
+
+/****************************************************
+ *******  get error index from r3 pattern    ********
+ ***************************************************/
+get_idx:				/* r3 = (MSW(r3) !=0)*2 +
+					    (LSW(r3) !=0) */
+	/* save the return info on stack */
+	mflr	r0			/* Get link register */
+	stwu	r1, -12(r1)		/* Save back chain and move SP */
+	stw	r0, +16(r1)		/* Save link register */
+	stw	r4, +8(r1)		/* save R4 */
+
+	andi.	r4, r3, 0xffff		/* check for lower bits */
+	beq	gi2			/* skip if no bits set */
+	andis.	r4, r3, 0xffff		/* check for upper bits */
+	beq	gi3			/* skip if no bits set */
+	addi	r3, 0, 3		/* both upper and lower bits set */
+	b	gi_done
+gi2:	andis.	r4, r3, 0xffff		/* check for upper bits*/
+	beq	gi4			/* skip if no bits set */
+	addi	r3, 0, 2		/* only upper bits set */
+	b	gi_done
+gi3:	addi	r3, 0, 1		/* only lower bits set */
+	b	gi_done
+gi4:	addi	r3, 0, 0		/* no bits set */
+gi_done:
+	/* restore stack and return */
+	lwz	r0, +16(r1)		/* Get saved link register */
+	mtlr	r0			/* Restore link register */
+	lwz	r4, +8(r1)		/* restore r4 */
+	addi	r1, r1, +12		/* Remove frame from stack */
+	blr				/* Return to calling function */
+
+/****************************************************
+ ********       set LED to R5 and hang       ********
+ ***************************************************/
+log_stat:				/* output a led code and continue */
+set_led:
+	/* save the return info on stack */
+	mflr	r0			/* Get link register */
+	stwu	r1, -12(r1)		/* Save back chain and move SP */
+	stw	r0, +16(r1)		/* Save link register */
+	stw	r4, +8(r1)		/* save R4 */
+
+	addis	r4, 0, 0xfe00		/* LED buffer is at 0xfe000000 */
+#if defined(CONFIG_W7OLMG)		/* only on gateway, invert outputs */
+	xori	r3,r3, 0xffff		/* complement led code, active low */
+	sth	r3, 0(r4)		/* store first test value */
+	xori	r3,r3, 0xffff		/* complement led code, active low */
+#else					/* if not gateway, then don't invert */
+	sth	r3, 0(r4)		/* store first test value */
+#endif
+
+	/* restore stack and return */
+	lwz	r0, +16(r1)		/* Get saved link register */
+	mtlr	r0			/* Restore link register */
+	lwz	r4, +8(r1)		/* restore r4 */
+	addi	r1, r1, +12		/* Remove frame from stack */
+	blr				/* Return to calling function */
+
+get_led:
+	/* save the return info on stack */
+	mflr	r0			/* Get link register */
+	stwu	r1, -12(r1)		/* Save back chain and move SP */
+	stw	r0, +16(r1)		/* Save link register */
+	stw	r4, +8(r1)		/* save R4 */
+
+	addis	r4, 0, 0xfe00		/* LED buffer is at 0xfe000000 */
+	lhz	r3, 0(r4)		/* store first test value */
+#if defined(CONFIG_W7OLMG)		/* only on gateway, invert inputs */
+	xori	r3,r3, 0xffff		/* complement led code, active low */
+#endif
+
+	/* restore stack and return */
+	lwz	r0, +16(r1)		/* Get saved link register */
+	mtlr	r0			/* Restore link register */
+	lwz	r4, +8(r1)		/* restore r4 */
+	addi	r1, r1, +12		/* Remove frame from stack */
+	blr				/* Return to calling function */
+
+log_err:	/* output the error and hang the board ( for now ) */
+	/* save the return info on stack */
+	mflr	r0			/* Get link register */
+	stwu	r1, -12(r1)		/* Save back chain and move SP */
+	stw	r0, +16(r1)		/* Save link register */
+	stw	r3, +8(r1)		/* save a copy of error code */
+	bl	set_led			/* set the led pattern */
+	GET_GOT				/* get GOT address in r14 */
+	lwz	r3,GOT(err_str)		/* get address of string */
+	bl	post_puts		/* output the warning string */
+	lwz	r3, +8(r1)		/* get error code */
+	addi	r4, 0, 2		/* set disp length to 2 nibbles */
+	bl	disp_hex		/* output the error code */
+	lwz	r3,GOT(end_str)		/* get address of string */
+	bl	post_puts		/* output the warning string */
+halt:
+	b	halt			/* hang */
+
+	/* restore stack and return */
+	lwz	r0, +16(r1)		/* Get saved link register */
+	mtlr	r0			/* Restore link register */
+	addi	r1, r1, +12		/* Remove frame from stack */
+	blr				/* Return to calling function */
+
+log_warn:	/* output a warning, then continue with operations */
+	/* save the return info on stack */
+	mflr	r0			/* Get link register */
+	stwu	r1, -16(r1)		/* Save back chain and move SP */
+	stw	r0, +20(r1)		/* Save link register */
+	stw	r3, +8(r1)		/* save a copy of error code */
+	stw	r14, +12(r1)		/* save a copy of r14 (used by GOT) */
+
+	bl	set_led			/* set the led pattern */
+	GET_GOT				/* get GOT address in r14 */
+	lwz	r3,GOT(warn_str)	/* get address of string */
+	bl	post_puts		/* output the warning string */
+	lwz	r3, +8(r1)		/* get error code */
+	addi	r4, 0, 2		/* set disp length to 2 nibbles */
+	bl	disp_hex		/* output the error code */
+	lwz	r3,GOT(end_str)		/* get address of string */
+	bl	post_puts		/* output the warning string */
+
+	addis	r3, 0, 64		/* has a long delay */
+	mtctr	r3
+log_2:
+	WATCHDOG_RESET			/* this keeps dog from barking, */
+				     	/*   and takes time */
+	bdnz	log_2			/* loop till time expires */
+
+	/* restore stack and return */
+	lwz	r0, +20(r1)		/* Get saved link register */
+	lwz	r14, +12(r1)		/* restore r14 */
+	mtlr	r0			/* Restore link register */
+	addi	r1, r1, +16		/* Remove frame from stack */
+	blr				/* Return to calling function */
+
+/*******************************************************************
+ *	temp_uart_init
+ *	Temporary UART initialization routine
+ *	Sets up UART0 to run at 9600N81 off of the internal clock.
+ *	R3-R4 are used.
+ ******************************************************************/
+temp_uart_init:
+	/* save the return info on stack */
+	mflr	r0			/* Get link register */
+	stwu	r1, -8(r1)		/* Save back chain and move SP */
+	stw	r0, +12(r1)		/* Save link register */
+
+        addis   r3, 0, 0xef60
+        ori     r3, r3, 0x0303          /* r3 = UART0_LCR */
+        addi    r4, 0, 0x83             /* n81 format, divisor regs enabled */
+        stb     r4, 0(r3)
+
+	/* set baud rate to use internal clock,
+	   baud = (200e6/16)/31/42 = 9600 */
+
+        addis   r3, 0, 0xef60		/* Address of baud divisor reg */
+        ori     r3, r3, 0x0300		/*   UART0_DLM */
+        addi    r4, 0, +42		/* uart baud divisor LSB = 93 */
+        stb     r4, 0(r3)               /* baud = (200 /16)/14/93 */
+
+        addi    r3, r3, 0x0001		/* uart baud divisor addr */
+        addi    r4, 0, 0
+        stb     r4, 0(r3)               /* Divisor Latch MSB = 0 */
+
+        addis   r3, 0, 0xef60
+        ori     r3, r3, 0x0303          /* r3 = UART0_LCR */
+        addi    r4, 0, 0x03             /* n81 format, tx/rx regs enabled */
+        stb     r4, 0(r3)
+
+	/* output a few line feeds */
+	addi	r3, 0, '\n'		/* load line feed */
+	bl 	post_putc		/* output the char */
+	addi	r3, 0, '\n'		/* load line feed */
+	bl 	post_putc		/* output the char */
+
+        /* restore stack and return */
+	lwz	r0, +12(r1)		/* Get saved link register */
+	mtlr	r0			/* Restore link register */
+	addi	r1, r1, +8		/* Remove frame from stack */
+	blr				/* Return to calling function */
+
+/**********************************************************************
+ **	post_putc
+ **	outputs charactor in R3
+ **	r3 returns the error code ( -1 if there is an error )
+ *********************************************************************/
+
+post_putc:
+
+	/* save the return info on stack */
+	mflr	r0			/* Get link register */
+	stwu	r1, -20(r1)		/* Save back chain and move SP */
+	stw	r0, +24(r1)		/* Save link register */
+	stmw	r29, 8(r1)		/* save	r29 - r31 on stack
+					   r31 - uart base address
+       					   r30 - delay counter
+					   r29 - scratch reg */
+
+     addis   r31, 0, 0xef60		/* Point to uart base */
+     ori     r31, r31, 0x0300
+     addis   r30, 0, 152 		/* Load about 10,000,000 ticks. */
+pputc_lp:
+	lbz     r29, 5(r31) 		/* Read Line Status Register */
+	andi.   r29, r29, 0x20		/* Check THRE status */
+	bne     thre_set		/* Branch if FIFO empty */
+	addic.  r30, r30, -1		/* Decrement and check if empty. */
+	bne     pputc_lp		/* Try, try again */
+	addi    r3, 0, -1		/* Load error code for timeout */
+	b       pputc_done 		/* Bail out with error code set */
+thre_set:
+	stb     r3, 0(r31)		/* Store character to UART */
+	addi	r3, 0, 0		/* clear error code */
+pputc_done:
+	lmw	r29, 8(r1)		/*restore r29 - r31 from stack */
+	lwz	r0, +24(r1)		/* Get saved link register */
+	addi	r1, r1, +20		/* Remove frame from stack */
+	mtlr	r0			/* Restore link register */
+	blr				/* Return to calling function */
+
+
+/****************************************************************
+    post_puts
+    Accepts a null-terminated string pointed to by R3
+    Outputs to the serial port until 0x00 is found.
+    r3 returns the error code ( -1 if there is an error )
+*****************************************************************/
+post_puts:
+
+	/* save the return info on stack */
+	mflr	r0			/* Get link register */
+	stwu	r1, -12(r1)		/* Save back chain and move SP */
+	stw	r0, +16(r1)		/* Save link register */
+	stw	r31, 8(r1)		/* save r31 - char pointer */
+
+	addi 	r31, r3, 0              /* move pointer to R31 */
+pputs_nxt:
+	lbz	r3, 0(r31)		/* Get next character */
+	addic.  r3, r3, 0		/* Check for zero */
+	beq	pputs_term		/* bail out if zero */
+	bl	post_putc		/* output the char */
+	addic.	r3, r3, 0		/* check for error */
+	bne	pputs_err
+	addi 	r31, r31, 1		/* point to next char */
+	b	pputs_nxt 		/* loop till term */
+pputs_err:
+	addi 	r3, 0, -1		/* set error code */
+	b	pputs_end		/* were outa here */
+pputs_term:
+	addi 	r3, 0, 1		/* set success code */
+ 	/* restore stack and return */
+pputs_end:
+	lwz	r31, 8(r1)		/* restore r27 - r31 from stack */
+	lwz	r0, +16(r1)		/* Get saved link register */
+	addi	r1, r1, +12		/* Remove frame from stack */
+	mtlr	r0			/* Restore link register */
+	blr				/* Return to calling function */
+
+
+
+/********************************************************************
+ *****	disp_hex
+ *****	Routine to display a hex value from a register.
+ *****	R3 is value to display
+ *****	R4 is number of nibbles to display ie 2 for byte 8 for (long)word
+ *****	Returns -1 in R3 if there is an error ( ie serial port hangs )
+ *****	Returns 0 in R3 if no error
+ *******************************************************************/
+disp_hex:
+	/* save the return info on stack */
+	mflr	r0			/* Get link register */
+	stwu	r1, -16(r1)		/* Save back chain and move SP */
+	stw	r0, +20(r1)		/* Save link register */
+	stmw	r30, 8(r1)		/* save r30 - r31 on stack */
+					/* r31 output char */
+					/* r30 uart base address */
+	addi 	r30, 0, 8               /* Go through 8 nibbles. */
+	addi 	r31, r3, 0
+pputh_nxt:
+	rlwinm	r31, r31, 4, 0, 31	/* Rotate next nibble into position */
+	andi. 	r3, r31, 0x0f		/* Get nibble. */
+	addi 	r3, r3, 0x30		/* Add zero's ASCII code. */
+	cmpwi	r3, 0x03a
+	blt	pputh_out
+	addi 	r3, r3, 0x07            /* 0x27 for lower case. */
+pputh_out:
+	cmpw 	r30, r4
+	bgt	pputh_skip
+	bl	post_putc
+	addic. 	r3, r3, 0 		/* check for error */
+	bne	pputh_err
+pputh_skip:
+	addic.	r30, r30, -1
+	bne	pputh_nxt
+	xor	r3, r3, r3		/* Clear error code */
+	b	pputh_done
+pputh_err:
+	addi 	r3, 0, -1 		/* set error code */
+pputh_done:
+        /* restore stack and return */
+	lmw	r30, 8(r1)		/*  restore r30 - r31 from stack */
+	lwz	r0, +20(r1)		/* Get saved link register */
+	addi	r1, r1, +16		/* Remove frame from stack */
+	mtlr	r0			/* Restore link register */
+	blr				/* Return to calling function */
+