[POWERPC] Split out the IOMMU logic from cell_dma_dev_setup()

Split the IOMMU logic out from cell_dma_dev_setup() into a separate
function.  If we're not using dma_direct_ops or dma_iommu_ops we don't
know what the hell's going on, so BUG.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/platforms/cell/iommu.c

@@ -507,17 +507,12 @@ static struct cbe_iommu *cell_iommu_for_node(int nid)
 
 static unsigned long cell_dma_direct_offset;
 
-static void cell_dma_dev_setup(struct device *dev)
+static void cell_dma_dev_setup_iommu(struct device *dev)
 {
 	struct iommu_window *window;
 	struct cbe_iommu *iommu;
 	struct dev_archdata *archdata = &dev->archdata;
 
-	if (get_pci_dma_ops() == &dma_direct_ops) {
-		archdata->dma_data = (void *)cell_dma_direct_offset;
-		return;
-	}
-
 	/* Current implementation uses the first window available in that
 	 * node's iommu. We -might- do something smarter later though it may
 	 * never be necessary
@@ -534,6 +529,18 @@ static void cell_dma_dev_setup(struct device *dev)
 	archdata->dma_data = &window->table;
 }
 
+static void cell_dma_dev_setup(struct device *dev)
+{
+	struct dev_archdata *archdata = &dev->archdata;
+
+	if (get_pci_dma_ops() == &dma_iommu_ops)
+		cell_dma_dev_setup_iommu(dev);
+	else if (get_pci_dma_ops() == &dma_direct_ops)
+		archdata->dma_data = (void *)cell_dma_direct_offset;
+	else
+		BUG();
+}
+
 static void cell_pci_dma_dev_setup(struct pci_dev *dev)
 {
 	cell_dma_dev_setup(&dev->dev);