powerpc/cell: move dma direct window setup out of dma_configure

Configure the dma settings at device setup time, and stop playing games
with get_pci_dma_ops.  This prepares for using the common dma_configure
code later on.

Includes fixes from Michael Ellerman.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/cell/iommu.c

@@ -656,14 +656,21 @@ static const struct dma_map_ops dma_iommu_fixed_ops = {
 	.unmap_page     = dma_fixed_unmap_page,
 };
 
+static u64 cell_iommu_get_fixed_address(struct device *dev);
+
 static void cell_dma_dev_setup(struct device *dev)
 {
-	if (get_pci_dma_ops() == &dma_iommu_ops)
+	if (get_pci_dma_ops() == &dma_iommu_ops) {
+		u64 addr = cell_iommu_get_fixed_address(dev);
+
+		if (addr != OF_BAD_ADDR)
+			set_dma_offset(dev, addr + dma_iommu_fixed_base);
 		set_iommu_table_base(dev, cell_get_iommu_table(dev));
-	else if (get_pci_dma_ops() == &dma_nommu_ops)
+	} else if (get_pci_dma_ops() == &dma_nommu_ops) {
 		set_dma_offset(dev, cell_dma_nommu_offset);
-	else
+	} else {
 		BUG();
+	}
 }
 
 static void cell_pci_dma_dev_setup(struct pci_dev *dev)
@@ -894,7 +901,11 @@ static u64 cell_iommu_get_fixed_address(struct device *dev)
 	const u32 *ranges = NULL;
 	int i, len, best, naddr, nsize, pna, range_size;
 
+	/* We can be called for platform devices that have no of_node */
 	np = of_node_get(dev->of_node);
+	if (!np)
+		goto out;
+
 	while (1) {
 		naddr = of_n_addr_cells(np);
 		nsize = of_n_size_cells(np);
@@ -949,19 +960,14 @@ static int dma_suported_and_switch(struct device *dev, u64 dma_mask)
 {
 	if (dma_mask == DMA_BIT_MASK(64) &&
 	    cell_iommu_get_fixed_address(dev) != OF_BAD_ADDR) {
-		u64 addr = cell_iommu_get_fixed_address(dev) +
-			dma_iommu_fixed_base;
 		dev_dbg(dev, "iommu: 64-bit OK, using fixed ops\n");
-		dev_dbg(dev, "iommu: fixed addr = %llx\n", addr);
 		set_dma_ops(dev, &dma_iommu_fixed_ops);
-		set_dma_offset(dev, addr);
 		return 1;
 	}
 
 	if (dma_iommu_dma_supported(dev, dma_mask)) {
 		dev_dbg(dev, "iommu: not 64-bit, using default ops\n");
-		set_dma_ops(dev, get_pci_dma_ops());
-		cell_dma_dev_setup(dev);
+		set_dma_ops(dev, &dma_iommu_ops);
 		return 1;
 	}