diff --git a/drivers/ata/pata_marvell.c b/drivers/ata/pata_marvell.c
index b066809ba9a1..c56f4043b0cc 100644
--- a/drivers/ata/pata_marvell.c
+++ b/drivers/ata/pata_marvell.c
@@ -83,6 +83,8 @@ static int marvell_cable_detect(struct ata_port *ap)
 	switch(ap->port_no)
 	{
 	case 0:
+		if (!ap->ioaddr.bmdma_addr)
+			return ATA_CBL_PATA_UNK;
 		if (ioread8(ap->ioaddr.bmdma_addr + 1) & 1)
 			return ATA_CBL_PATA40;
 		return ATA_CBL_PATA80;