diff --git a/arch/mips/loongson2ef/common/pci.c b/arch/mips/loongson2ef/common/pci.c
index 55524f9a7b96..0f11392104bf 100644
--- a/arch/mips/loongson2ef/common/pci.c
+++ b/arch/mips/loongson2ef/common/pci.c
@@ -17,7 +17,7 @@ static struct resource loongson_pci_mem_resource = {
 
 static struct resource loongson_pci_io_resource = {
 	.name	= "pci io space",
-	.start	= LOONGSON_PCI_IO_START,
+	.start	= 0x00000000UL, /* See loongson2ef_pcibios_init(). */
 	.end	= IO_SPACE_LIMIT,
 	.flags	= IORESOURCE_IO,
 };
@@ -77,6 +77,15 @@ void __init loongson2ef_pcibios_init(void)
 {
 	setup_pcimap();
 
+	/*
+	 * ISA-mode only IDE controllers have a hard dependency on ISA IO ports.
+	 *
+	 * Claim them by setting PCI IO space to start at 0x00000000, and set
+	 * PCIBIOS_MIN_IO to prevent non-legacy PCI devices from touching
+	 * reserved regions.
+	 */
+	PCIBIOS_MIN_IO = LOONGSON_PCI_IO_START;
+
 	loongson_pci_controller.io_map_base = mips_io_port_base;
 	register_pci_controller(&loongson_pci_controller);
 }