s390/pci: Fix unexpected write combine on resource

In the initial MIO support introduced in

commit 71ba41c ("s390/pci: provide support for MIO instructions")

zpci_map_resource() and zpci_setup_resources() default to using the
mio_wb address as the resource's start address. This means users of the
mapping, which includes most drivers, will get write combining on PCI
Stores. This may lead to problems when drivers expect write through
behavior when not using an explicit ioremap_wc().

Cc: stable@vger.kernel.org
Fixes: 71ba41c ("s390/pci: provide support for MIO instructions")
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

Author: niklas88

arch/s390/pci/pci.c

@@ -424,7 +424,7 @@ static void zpci_map_resources(struct pci_dev *pdev)
 
 		if (zpci_use_mio(zdev))
 			pdev->resource[i].start =
-				(resource_size_t __force) zdev->bars[i].mio_wb;
+				(resource_size_t __force) zdev->bars[i].mio_wt;
 		else
 			pdev->resource[i].start = (resource_size_t __force)
 				pci_iomap_range_fh(pdev, i, 0, 0);
@@ -531,7 +531,7 @@ static int zpci_setup_bus_resources(struct zpci_dev *zdev,
 			flags |= IORESOURCE_MEM_64;
 
 		if (zpci_use_mio(zdev))
-			addr = (unsigned long) zdev->bars[i].mio_wb;
+			addr = (unsigned long) zdev->bars[i].mio_wt;
 		else
 			addr = ZPCI_ADDR(entry);
 		size = 1UL << zdev->bars[i].size;