diff --git a/arch/i386/cpu/sc520/sc520.c b/arch/i386/cpu/sc520/sc520.c
index 4b566a7..519bfd8 100644
--- a/arch/i386/cpu/sc520/sc520.c
+++ b/arch/i386/cpu/sc520/sc520.c
@@ -44,24 +44,24 @@
 	/* Set the UARTxCTL register at it's slower,
 	 * baud clock giving us a 1.8432 MHz reference
 	 */
-	sc520_mmcr->uart1ctl = 0x07;
-	sc520_mmcr->uart2ctl = 0x07;
+	writeb(0x07, &sc520_mmcr->uart1ctl);
+	writeb(0x07, &sc520_mmcr->uart2ctl);
 
 	/* first set the timer pin mapping */
-	sc520_mmcr->clksel = 0x72;	/* no clock frequency selected, use 1.1892MHz */
+	writeb(0x72, &sc520_mmcr->clksel);	/* no clock frequency selected, use 1.1892MHz */
 
 	/* enable PCI bus arbitrer */
-	sc520_mmcr->sysarbctl = 0x02;	/* enable concurrent mode */
+	writeb(0x02, &sc520_mmcr->sysarbctl);	/* enable concurrent mode */
 
-	sc520_mmcr->sysarbmenb = 0x1f;	/* enable external grants */
-	sc520_mmcr->hbctl = 0x04;	/* enable posted-writes */
+	writeb(0x1f, &sc520_mmcr->sysarbmenb);	/* enable external grants */
+	writeb(0x04, &sc520_mmcr->hbctl);	/* enable posted-writes */
 
 	if (CONFIG_SYS_SC520_HIGH_SPEED) {
-		sc520_mmcr->cpuctl = 0x02;	/* set it to 133 MHz and write back */
+		writeb(0x02, &sc520_mmcr->cpuctl);	/* set it to 133 MHz and write back */
 		gd->cpu_clk = 133000000;
 		printf("## CPU Speed set to 133MHz\n");
 	} else {
-		sc520_mmcr->cpuctl = 0x01;	/* set it to 100 MHz and write back */
+		writeb(0x01, &sc520_mmcr->cpuctl);	/* set it to 100 MHz and write back */
 		printf("## CPU Speed set to 100MHz\n");
 		gd->cpu_clk = 100000000;
 	}
@@ -74,7 +74,7 @@
 	    "loop 0b\n": : : "ecx");
 
 	/* turn on the SDRAM write buffer */
-	sc520_mmcr->dbctl = 0x11;
+	writeb(0x11, &sc520_mmcr->dbctl);
 
 	/* turn on the cache and disable write through */
 	asm("movl	%%cr0, %%eax\n"
@@ -88,6 +88,7 @@
 
 	u32 dram_present=0;
 	u32 dram_ctrl;
+
 #ifdef CONFIG_SYS_SDRAM_DRCTMCTL
 	/* these memory control registers are set up in the assember part,
 	 * in sc520_asm.S, during 'mem_init'.  If we muck with them here,
@@ -97,7 +98,8 @@
 	 * simply dictates it.
 	 */
 #else
-	int val;
+	u8 tmp;
+	u8 val;
 
 	int cas_precharge_delay = CONFIG_SYS_SDRAM_PRECHARGE_DELAY;
 	int refresh_rate        = CONFIG_SYS_SDRAM_REFRESH_RATE;
@@ -116,9 +118,10 @@
 		val = 3;  /* 62.4us */
 	}
 
-	sc520_mmcr->drcctl = (sc520_mmcr->drcctl & 0xcf) | (val<<4);
+	tmp = (readb(&sc520_mmcr->drcctl) & 0xcf) | (val<<4);
+	writeb(tmp, &sc520_mmcr->drcctl);
 
-	val = sc520_mmcr->drctmctl & 0xf0;
+	val = readb(&sc520_mmcr->drctmctl) & 0xf0;
 
 	if (cas_precharge_delay==3) {
 		val |= 0x04;   /* 3T */
@@ -133,12 +136,12 @@
 	} else {
 		val |= 1;
 	}
-	sc520_mmcr->drctmctl = val;
+	writeb(val, &c520_mmcr->drctmctl);
 #endif
 
 	/* We read-back the configuration of the dram
 	 * controller that the assembly code wrote */
-	dram_ctrl = sc520_mmcr->drcbendadr;
+	dram_ctrl = readl(&sc520_mmcr->drcbendadr);
 
 	bd->bi_dram[0].start = 0;
 	if (dram_ctrl & 0x80) {
@@ -191,7 +194,7 @@
 {
 	printf("Resetting using SC520 MMCR\n");
 	/* Write a '1' to the SYS_RST of the RESCFG MMCR */
-	sc520_mmcr->rescfg = 0x01;
+	writeb(0x01, &sc520_mmcr->rescfg);
 
 	/* NOTREACHED */
 }
diff --git a/arch/i386/cpu/sc520/sc520_pci.c b/arch/i386/cpu/sc520/sc520_pci.c
index f446c6d..ee7e720 100644
--- a/arch/i386/cpu/sc520/sc520_pci.c
+++ b/arch/i386/cpu/sc520/sc520_pci.c
@@ -25,6 +25,7 @@
 
 #include <common.h>
 #include <pci.h>
+#include <asm/io.h>
 #include <asm/pci.h>
 #include <asm/ic/sc520.h>
 
@@ -63,6 +64,8 @@
 int pci_sc520_set_irq(int pci_pin, int irq)
 {
 	int i;
+	u8 tmpb;
+	u16 tmpw;
 
 # if 1
 	printf("set_irq(): map INT%c to IRQ%d\n", pci_pin + 'A', irq);
@@ -80,31 +83,34 @@
 
 	/* PCI interrupt mapping (A through D)*/
 	for (i=0; i<=3 ;i++) {
-		if (sc520_mmcr->pci_int_map[i] == sc520_irq[irq].priority)
-			sc520_mmcr->pci_int_map[i] = SC520_IRQ_DISABLED;
+		if (readb(&sc520_mmcr->pci_int_map[i]) == sc520_irq[irq].priority)
+			writeb(SC520_IRQ_DISABLED, &sc520_mmcr->pci_int_map[i]);
 	}
 
 	/* GP IRQ interrupt mapping */
 	for (i=0; i<=10 ;i++) {
-		if (sc520_mmcr->gp_int_map[i] == sc520_irq[irq].priority)
-			sc520_mmcr->gp_int_map[i] = SC520_IRQ_DISABLED;
+		if (readb(&sc520_mmcr->gp_int_map[i]) == sc520_irq[irq].priority)
+			writeb(SC520_IRQ_DISABLED, &sc520_mmcr->gp_int_map[i]);
 	}
 
 	/* Set the trigger to level */
-	sc520_mmcr->pic_mode[sc520_irq[irq].level_reg] =
-		sc520_mmcr->pic_mode[sc520_irq[irq].level_reg] | sc520_irq[irq].level_bit;
+	tmpb = readb(&sc520_mmcr->pic_mode[sc520_irq[irq].level_reg]);
+	tmpb |= sc520_irq[irq].level_bit;
+	writeb(tmpb, &sc520_mmcr->pic_mode[sc520_irq[irq].level_reg]);
 
 
 	if (pci_pin < 4) {
 		/* PCI INTA-INTD */
 		/* route the interrupt */
-		sc520_mmcr->pci_int_map[pci_pin] = sc520_irq[irq].priority;
+		writeb(sc520_irq[irq].priority, &sc520_mmcr->pci_int_map[pci_pin]);
 	} else {
 		/* GPIRQ0-GPIRQ10 used for additional PCI INTS */
-		sc520_mmcr->gp_int_map[pci_pin - 4] = sc520_irq[irq].priority;
+		writeb(sc520_irq[irq].priority, &sc520_mmcr->gp_int_map[pci_pin - 4]);
 
 		/* also set the polarity in this case */
-		sc520_mmcr->intpinpol = sc520_mmcr->intpinpol | (1 << (pci_pin-4));
+		tmpw = readw(&sc520_mmcr->intpinpol);
+		tmpw |= (1 << (pci_pin-4));
+		writew(tmpw, &sc520_mmcr->intpinpol);
 	}
 
 	/* register the pin */
diff --git a/arch/i386/cpu/sc520/sc520_ssi.c b/arch/i386/cpu/sc520/sc520_ssi.c
index 8dbe17a..6e5e346 100644
--- a/arch/i386/cpu/sc520/sc520_ssi.c
+++ b/arch/i386/cpu/sc520/sc520_ssi.c
@@ -24,6 +24,7 @@
 /* stuff specific for the sc520, but independent of implementation */
 
 #include <common.h>
+#include <asm/io.h>
 #include <asm/ic/ssi.h>
 #include <asm/ic/sc520.h>
 
@@ -61,34 +62,34 @@
 		temp |= PHS_INV_ENB;
 	}
 
-	sc520_mmcr->ssictl = temp;
+	writeb(temp, &sc520_mmcr->ssictl);
 
 	return 0;
 }
 
 u8 ssi_txrx_byte(u8 data)
 {
-	sc520_mmcr->ssixmit = data;
-	while (sc520_mmcr->ssista & SSISTA_BSY);
-	sc520_mmcr->ssicmd = SSICMD_CMD_SEL_XMITRCV;
-	while (sc520_mmcr->ssista & SSISTA_BSY);
+	writeb(data, &sc520_mmcr->ssixmit);
+	while (readb(&sc520_mmcr->ssista) & SSISTA_BSY);
+	writeb(SSICMD_CMD_SEL_XMITRCV, &sc520_mmcr->ssicmd);
+	while (readb(&sc520_mmcr->ssista) & SSISTA_BSY);
 
-	return sc520_mmcr->ssircv;
+	return readb(&sc520_mmcr->ssircv);
 }
 
 
 void ssi_tx_byte(u8 data)
 {
-	sc520_mmcr->ssixmit = data;
-	while (sc520_mmcr->ssista & SSISTA_BSY);
-	sc520_mmcr->ssicmd = SSICMD_CMD_SEL_XMIT;
+	writeb(data, &sc520_mmcr->ssixmit);
+	while (readb(&sc520_mmcr->ssista) & SSISTA_BSY);
+	writeb(SSICMD_CMD_SEL_XMIT, &sc520_mmcr->ssicmd);
 }
 
 u8 ssi_rx_byte(void)
 {
-	while (sc520_mmcr->ssista & SSISTA_BSY);
-	sc520_mmcr->ssicmd = SSICMD_CMD_SEL_RCV;
-	while (sc520_mmcr->ssista & SSISTA_BSY);
+	while (readb(&sc520_mmcr->ssista) & SSISTA_BSY);
+	writeb(SSICMD_CMD_SEL_RCV, &sc520_mmcr->ssicmd);
+	while (readb(&sc520_mmcr->ssista) & SSISTA_BSY);
 
-	return sc520_mmcr->ssircv;
+	return readb(&sc520_mmcr->ssircv);
 }
diff --git a/arch/i386/cpu/sc520/sc520_timer.c b/arch/i386/cpu/sc520/sc520_timer.c
index 93b5b55..eca48e0 100644
--- a/arch/i386/cpu/sc520/sc520_timer.c
+++ b/arch/i386/cpu/sc520/sc520_timer.c
@@ -24,13 +24,14 @@
 /* stuff specific for the sc520, but independent of implementation */
 
 #include <common.h>
+#include <asm/io.h>
 #include <asm/interrupt.h>
 #include <asm/ic/sc520.h>
 
 void sc520_timer_isr(void)
 {
 	/* Ack the GP Timer Interrupt */
-	sc520_mmcr->gptmrsta = 0x02;
+	writeb(0x02, &sc520_mmcr->gptmrsta);
 }
 
 int timer_init(void)
@@ -42,28 +43,28 @@
 	irq_install_handler (0, timer_isr, NULL);
 
 	/* Map GP Timer 1 to Master PIC IR0  */
-	sc520_mmcr->gp_tmr_int_map[1] = 0x01;
+	writeb(0x01, &sc520_mmcr->gp_tmr_int_map[1]);
 
 	/* Disable GP Timers 1 & 2 - Allow configuration writes */
-	sc520_mmcr->gptmr1ctl = 0x4000;
-	sc520_mmcr->gptmr2ctl = 0x4000;
+	writew(0x4000, &sc520_mmcr->gptmr1ctl);
+	writew(0x4000, &sc520_mmcr->gptmr2ctl);
 
 	/* Reset GP Timers 1 & 2 */
-	sc520_mmcr->gptmr1cnt = 0x0000;
-	sc520_mmcr->gptmr2cnt = 0x0000;
+	writew(0x0000, &sc520_mmcr->gptmr1cnt);
+	writew(0x0000, &sc520_mmcr->gptmr2cnt);
 
 	/* Setup GP Timer 2 as a 100kHz (10us) prescaler */
-	sc520_mmcr->gptmr2maxcmpa = 83;
-	sc520_mmcr->gptmr2ctl = 0xc001;
+	writew(83, &sc520_mmcr->gptmr2maxcmpa);
+	writew(0xc001, &sc520_mmcr->gptmr2ctl);
 
 	/* Setup GP Timer 1 as a 1000 Hz (1ms) interrupt generator */
-	sc520_mmcr->gptmr1maxcmpa = 100;
-	sc520_mmcr->gptmr1ctl = 0xe009;
+	writew(100, &sc520_mmcr->gptmr1maxcmpa);
+	writew(0xe009, &sc520_mmcr->gptmr1ctl);
 
 	unmask_irq (0);
 
 	/* Clear the GP Timer 1 status register to get the show rolling*/
-	sc520_mmcr->gptmrsta = 0x02;
+	writeb(0x02, &sc520_mmcr->gptmrsta);
 
 	return 0;
 }
@@ -74,11 +75,11 @@
 	long u;
 	long temp;
 
-	temp = sc520_mmcr->swtmrmilli;
-	temp = sc520_mmcr->swtmrmicro;
+	temp = readw(&sc520_mmcr->swtmrmilli);
+	temp = readw(&sc520_mmcr->swtmrmicro);
 
 	do {
-		m += sc520_mmcr->swtmrmilli;
-		u = sc520_mmcr->swtmrmicro + (m * 1000);
+		m += readw(&sc520_mmcr->swtmrmilli);
+		u = readw(&sc520_mmcr->swtmrmicro) + (m * 1000);
 	} while (u < usec);
 }