From owner-p4-projects@FreeBSD.ORG  Mon Apr 10 18:10:14 2006
Return-Path: <owner-p4-projects@FreeBSD.ORG>
X-Original-To: p4-projects@freebsd.org
Delivered-To: p4-projects@freebsd.org
Received: by hub.freebsd.org (Postfix, from userid 32767)
	id 2458016A406; Mon, 10 Apr 2006 18:10:14 +0000 (UTC)
X-Original-To: perforce@freebsd.org
Delivered-To: perforce@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 030F316A400
	for <perforce@freebsd.org>; Mon, 10 Apr 2006 18:10:13 +0000 (UTC)
	(envelope-from imp@freebsd.org)
Received: from repoman.freebsd.org (repoman.freebsd.org [216.136.204.115])
	by mx1.FreeBSD.org (Postfix) with ESMTP id ABD6843D48
	for <perforce@freebsd.org>; Mon, 10 Apr 2006 18:10:13 +0000 (GMT)
	(envelope-from imp@freebsd.org)
Received: from repoman.freebsd.org (localhost [127.0.0.1])
	by repoman.freebsd.org (8.13.1/8.13.1) with ESMTP id k3AIADuc008304
	for <perforce@freebsd.org>; Mon, 10 Apr 2006 18:10:13 GMT
	(envelope-from imp@freebsd.org)
Received: (from perforce@localhost)
	by repoman.freebsd.org (8.13.1/8.13.1/Submit) id k3AIADQC008301
	for perforce@freebsd.org; Mon, 10 Apr 2006 18:10:13 GMT
	(envelope-from imp@freebsd.org)
Date: Mon, 10 Apr 2006 18:10:13 GMT
Message-Id: <200604101810.k3AIADQC008301@repoman.freebsd.org>
X-Authentication-Warning: repoman.freebsd.org: perforce set sender to
	imp@freebsd.org using -f
From: Warner Losh <imp@FreeBSD.org>
To: Perforce Change Reviews <perforce@freebsd.org>
Cc: 
Subject: PERFORCE change 94927 for review
X-BeenThere: p4-projects@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: p4 projects tree changes <p4-projects.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/p4-projects>,
	<mailto:p4-projects-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/p4-projects>
List-Post: <mailto:p4-projects@freebsd.org>
List-Help: <mailto:p4-projects-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/p4-projects>,
	<mailto:p4-projects-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 10 Apr 2006 18:10:14 -0000

http://perforce.freebsd.org/chv.cgi?CH=94927

Change 94927 by imp@imp_Speedy on 2006/04/10 18:09:42

	Use a volatile pointer to write to the memory, rather than just
	a bunch of back to back writes.  This bloats us back to 1084,
	but is necessary to stabilize the SDRAM.

Affected files ...

.. //depot/projects/arm/src/sys/boot/arm/kb920x/boot0/at91rm9200_lowlevel.c#5 edit

Differences ...

==== //depot/projects/arm/src/sys/boot/arm/kb920x/boot0/at91rm9200_lowlevel.c#5 (text+ko) ====

@@ -49,6 +49,7 @@
 
 	register unsigned	value;
 	int i;
+	volatile unsigned short *p = (unsigned short *)SDRAM_BASE;
 
 	AT91C_BASE_PIOC->PIO_PER = AT91C_PIO_PC10;
 	AT91C_BASE_PIOC->PIO_OER = AT91C_PIO_PC10;
@@ -139,30 +140,30 @@
 
 	AT91C_BASE_SDRC->SDRC_MR =
 		AT91C_SDRC_DBW_16_BITS | AT91C_SDRC_MODE_PRCGALL_CMD;
-	*(unsigned short*)SDRAM_BASE = 0;
+	*p = 0;
 
 	AT91C_BASE_SDRC->SDRC_MR = 
 		AT91C_SDRC_DBW_16_BITS | AT91C_SDRC_MODE_RFSH_CMD;
-	*(unsigned short*)SDRAM_BASE = 0;
-	*(unsigned short*)SDRAM_BASE = 0;
-	*(unsigned short*)SDRAM_BASE = 0;
-	*(unsigned short*)SDRAM_BASE = 0;
-	*(unsigned short*)SDRAM_BASE = 0;
-	*(unsigned short*)SDRAM_BASE = 0;
-	*(unsigned short*)SDRAM_BASE = 0;
-	*(unsigned short*)SDRAM_BASE = 0;
+	*p = 0;
+	*p = 0;
+	*p = 0;
+	*p = 0;
+	*p = 0;
+	*p = 0;
+	*p = 0;
+	*p = 0;
 
 	AT91C_BASE_SDRC->SDRC_MR =
 		AT91C_SDRC_DBW_16_BITS | AT91C_SDRC_MODE_LMR_CMD;
-	*(unsigned short*)SDRAM_BASE = 0;
+	*p = 0;
 
 	AT91C_BASE_SDRC->SDRC_TR = 7 * AT91C_MASTER_CLOCK / 1000000;
 
-	*(unsigned short*)SDRAM_BASE = 0;
+	*p = 0;
 
 	AT91C_BASE_SDRC->SDRC_MR =
 	    AT91C_SDRC_DBW_16_BITS | AT91C_SDRC_MODE_NORMAL_CMD;
-	*(unsigned short*)SDRAM_BASE = 0;
+	*p = 0;
 
 	// Configure DBGU -use local routine optimized for space
 	pPio->PIO_ASR = AT91C_PA31_DTXD | AT91C_PA30_DRXD;