diff --git a/arch/powerpc/include/asm/device.h b/arch/powerpc/include/asm/device.h
index a3954e4fcbe2edbc5466e8d2ff4bffb16ca57312..16d25c0974be9d7a4afa7c60f9b11942735caa16 100644
--- a/arch/powerpc/include/asm/device.h
+++ b/arch/powerpc/include/asm/device.h
@@ -9,6 +9,12 @@
 struct dma_map_ops;
 struct device_node;
 
+/*
+ * Arch extensions to struct device.
+ *
+ * When adding fields, consider macio_add_one_device in
+ * drivers/macintosh/macio_asic.c
+ */
 struct dev_archdata {
 	/* DMA operations on that device */
 	struct dma_map_ops	*dma_ops;
diff --git a/drivers/macintosh/macio_asic.c b/drivers/macintosh/macio_asic.c
index b6e7ddc09d76573eb0b423747bb613ce16599a7d..4daf9e5a7736f415023ff1ce07d6cb2d79d526b9 100644
--- a/drivers/macintosh/macio_asic.c
+++ b/drivers/macintosh/macio_asic.c
@@ -387,11 +387,10 @@ static struct macio_dev * macio_add_one_device(struct macio_chip *chip,
 	/* Set the DMA ops to the ones from the PCI device, this could be
 	 * fishy if we didn't know that on PowerMac it's always direct ops
 	 * or iommu ops that will work fine
+	 *
+	 * To get all the fields, copy all archdata
 	 */
-	dev->ofdev.dev.archdata.dma_ops =
-		chip->lbus.pdev->dev.archdata.dma_ops;
-	dev->ofdev.dev.archdata.dma_data =
-		chip->lbus.pdev->dev.archdata.dma_data;
+	dev->ofdev.dev.archdata = chip->lbus.pdev->dev.archdata;
 #endif /* CONFIG_PCI */
 
 #ifdef DEBUG