PCI: Update BARs using property bits appropriate for type

The BAR property bits (0-3 for memory BARs, 0-1 for I/O BARs) are supposed
to be read-only, but we do save them in res->flags and include them when
updating the BAR.

Mask the I/O property bits with ~PCI_BASE_ADDRESS_IO_MASK (0x3) instead of
PCI_REGION_FLAG_MASK (0xf) to make it obvious that we can't corrupt bits
2-3 of I/O addresses.

Use PCI_ROM_ADDRESS_MASK for ROM BARs.  This means we'll only check the top
21 bits (instead of the 28 bits we used to check) of a ROM BAR to see if
the update was successful.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/setup-res.c

@@ -59,12 +59,17 @@ void pci_update_resource(struct pci_dev *dev, int resno)
 		return;
 
 	pcibios_resource_to_bus(dev->bus, &region, res);
+	new = region.start;
 
-	new = region.start | (res->flags & PCI_REGION_FLAG_MASK);
-	if (res->flags & IORESOURCE_IO)
+	if (res->flags & IORESOURCE_IO) {
 		mask = (u32)PCI_BASE_ADDRESS_IO_MASK;
-	else
+		new |= res->flags & ~PCI_BASE_ADDRESS_IO_MASK;
+	} else if (resno == PCI_ROM_RESOURCE) {
+		mask = (u32)PCI_ROM_ADDRESS_MASK;
+	} else {
 		mask = (u32)PCI_BASE_ADDRESS_MEM_MASK;
+		new |= res->flags & ~PCI_BASE_ADDRESS_MEM_MASK;
+	}
 
 	reg = pci_resource_bar(dev, resno, &type);
 	if (!reg)