diff -urN -x CVS linux-2.6.32/drivers/mmc/host/at91_mci.c linux-2.6/drivers/mmc/host/at91_mci.c
--- linux-2.6.32/drivers/mmc/host/at91_mci.c	2010-01-28 20:30:25.000000000 +0200
+++ linux-2.6/drivers/mmc/host/at91_mci.c	2009-12-14 21:55:58.000000000 +0200
@@ -201,7 +201,7 @@
	len = data->sg_len;

	/* AT91SAM926[0/3] Data Write Operation and number of bytes erratum */
-	if (cpu_is_at91sam9260() || cpu_is_at91sam9263())
+	if (cpu_is_at91sam9260() || cpu_is_at91sam9263() || cpu_is_at91sam9g20())
		if (host->total_length == 12)
			memset(dmabuf, 0, 12);

@@ -461,7 +461,7 @@
	at91_mci_write(host, AT91_MCI_DTOR, AT91_MCI_DTOMUL_1M | AT91_MCI_DTOCYC);
	mr = AT91_MCI_PDCMODE | 0x34a;

-	if (cpu_is_at91sam9260() || cpu_is_at91sam9263())
+	if (cpu_is_at91sam9260() || cpu_is_at91sam9263() || cpu_is_at91sam9g20())
		mr |= AT91_MCI_RDPROOF | AT91_MCI_WRPROOF;

	at91_mci_write(host, AT91_MCI_MR, mr);
@@ -617,7 +617,7 @@
				 * AT91SAM926[0/3] Data Write Operation and
				 * number of bytes erratum
				 */
-				if (cpu_is_at91sam9260 () || cpu_is_at91sam9263())
+				if (cpu_is_at91sam9260 () || cpu_is_at91sam9263() || cpu_is_at91sam9g20())
					if (host->total_length < 12)
						host->total_length = 12;

@@ -1017,7 +1017,7 @@
	host->bus_mode = 0;
	host->board = pdev->dev.platform_data;
	if (host->board->wire4) {
-		if (cpu_is_at91sam9260() || cpu_is_at91sam9263())
+		if (cpu_is_at91sam9260() || cpu_is_at91sam9263() || cpu_is_at91sam9g20())
			mmc->caps |= MMC_CAP_4_BIT_DATA;
		else
			dev_warn(&pdev->dev, "4 wire bus mode not supported"