[MIPS] No ide_default_io_base() if PCI IDE was not found

Revert b5438582090406e2ccb4169d9b2df7c9939ae42b and add
no_pci_devices() check to avoid crash due to early calling of
pci_get_class().

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

include/asm-mips/mach-generic/ide.h

@@ -29,6 +29,35 @@
 
 #define IDE_ARCH_OBSOLETE_DEFAULTS
 
+static __inline__ int ide_probe_legacy(void)
+{
+#ifdef CONFIG_PCI
+	struct pci_dev *dev;
+	/*
+	 * This can be called on the ide_setup() path, super-early in
+	 * boot.  But the down_read() will enable local interrupts,
+	 * which can cause some machines to crash.  So here we detect
+	 * and flag that situation and bail out early.
+	 */
+	if (no_pci_devices())
+		return 0;
+	dev = pci_get_class(PCI_CLASS_BRIDGE_EISA << 8, NULL);
+	if (dev)
+		goto found;
+	dev = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, NULL);
+	if (dev)
+		goto found;
+	return 0;
+found:
+	pci_dev_put(dev);
+	return 1;
+#elif defined(CONFIG_EISA) || defined(CONFIG_ISA)
+	return 1;
+#else
+	return 0;
+#endif
+}
+
 static __inline__ int ide_default_irq(unsigned long base)
 {
 	switch (base) {
@@ -45,6 +74,8 @@ static __inline__ int ide_default_irq(unsigned long base)
 
 static __inline__ unsigned long ide_default_io_base(int index)
 {
+	if (!ide_probe_legacy())
+		return 0;
 	/*
 	 *      If PCI is present then it is not safe to poke around
 	 *      the other legacy IDE ports. Only 0x1f0 and 0x170 are