powerpc: setup default archdata for {of_}platform via bus_register_notifier

Since a number of powerpc chips are SoCs we end up having dma-able
devices that are registered as platform or of_platform devices.  We need
to hook the archdata to setup proper dma_ops for these devices.

Rather than having to add a bus_notify to each platform we add a default
one at the highest priority (called first) to set the default dma_ops for
of_platform and platform devices to dma_direct_ops.  This allows platform
code to override the ops by providing their own notifier call back.

In the future to enable >4G DMA support on ppc32 we can hook swiotlb ops.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/setup-common.c

@@ -35,6 +35,8 @@
 #include <linux/debugfs.h>
 #include <linux/percpu.h>
 #include <linux/lmb.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
 #include <asm/io.h>
 #include <asm/prom.h>
 #include <asm/processor.h>
@@ -669,3 +671,37 @@ static int powerpc_debugfs_init(void)
 }
 arch_initcall(powerpc_debugfs_init);
 #endif
+
+static int ppc_dflt_bus_notify(struct notifier_block *nb,
+				unsigned long action, void *data)
+{
+	struct device *dev = data;
+
+	/* We are only intereted in device addition */
+	if (action != BUS_NOTIFY_ADD_DEVICE)
+		return 0;
+
+	set_dma_ops(dev, &dma_direct_ops);
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block ppc_dflt_plat_bus_notifier = {
+	.notifier_call = ppc_dflt_bus_notify,
+	.priority = INT_MAX,
+};
+
+static struct notifier_block ppc_dflt_of_bus_notifier = {
+	.notifier_call = ppc_dflt_bus_notify,
+	.priority = INT_MAX,
+};
+
+static int __init setup_bus_notifier(void)
+{
+	bus_register_notifier(&platform_bus_type, &ppc_dflt_plat_bus_notifier);
+	bus_register_notifier(&of_platform_bus_type, &ppc_dflt_of_bus_notifier);
+
+	return 0;
+}
+
+arch_initcall(setup_bus_notifier);

arch/powerpc/platforms/cell/qpace_setup.c

@@ -81,16 +81,6 @@ static int __init qpace_publish_devices(void)
 }
 machine_subsys_initcall(qpace, qpace_publish_devices);
 
-extern int qpace_notify(struct device *dev)
-{
-	/* set dma_ops for of_platform bus */
-	if (dev->bus && dev->bus->name
-			&& !strcmp(dev->bus->name, "of_platform"))
-		set_dma_ops(dev, &dma_direct_ops);
-
-	return 0;
-}
-
 static void __init qpace_setup_arch(void)
 {
 #ifdef CONFIG_SPU_BASE
@@ -115,9 +105,6 @@ static void __init qpace_setup_arch(void)
 #ifdef CONFIG_DUMMY_CONSOLE
 	conswitchp = &dummy_con;
 #endif
-
-	/* set notifier function */
-	platform_notify = &qpace_notify;
 }
 
 static int __init qpace_probe(void)