[PATCH] Move device/driver code to drivers/base/dd.c

This relocates the driver binding/unbinding code to drivers/base/dd.c. This is done
for two reasons: One, it's not code related to the bus_type itself; it uses some from
that, some from devices, and some from drivers. And Two, it will make it easier to do
some of the upcoming lock removal on that code..

Signed-off-by: Patrick Mochel <mochel@digitalimplant.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 200 insertions, 0 deletions

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
new file mode 100644
index 00000000000..b709b1e0cb2
--- /dev/null
+++ b/drivers/base/dd.c
@@ -0,0 +1,200 @@
+/*
+ *	drivers/base/dd.c - The core device/driver interactions.
+ *
+ * 	This file contains the (sometimes tricky) code that controls the
+ *	interactions between devices and drivers, which primarily includes
+ *	driver binding and unbinding.
+ *
+ *	All of this code used to exist in drivers/base/bus.c, but was
+ *	relocated to here in the name of compartmentalization (since it wasn't
+ *	strictly code just for the 'struct bus_type'.
+ *
+ *	Copyright (c) 2002-5 Patrick Mochel
+ *	Copyright (c) 2002-3 Open Source Development Labs
+ *
+ *	This file is released under the GPLv2
+ */
+
+#include <linux/device.h>
+#include <linux/module.h>
+
+#include "base.h"
+#include "power/power.h"
+
+#define to_drv(node) container_of(node, struct device_driver, kobj.entry)
+
+
+/**
+ *	device_bind_driver - bind a driver to one device.
+ *	@dev:	device.
+ *
+ *	Allow manual attachment of a driver to a device.
+ *	Caller must have already set @dev->driver.
+ *
+ *	Note that this does not modify the bus reference count
+ *	nor take the bus's rwsem. Please verify those are accounted
+ *	for before calling this. (It is ok to call with no other effort
+ *	from a driver's probe() method.)
+ */
+void device_bind_driver(struct device * dev)
+{
+	pr_debug("bound device '%s' to driver '%s'\n",
+		 dev->bus_id, dev->driver->name);
+	list_add_tail(&dev->driver_list, &dev->driver->devices);
+	sysfs_create_link(&dev->driver->kobj, &dev->kobj,
+			  kobject_name(&dev->kobj));
+	sysfs_create_link(&dev->kobj, &dev->driver->kobj, "driver");
+}
+
+/**
+ *	driver_probe_device - attempt to bind device & driver.
+ *	@drv:	driver.
+ *	@dev:	device.
+ *
+ *	First, we call the bus's match function, if one present, which
+ *	should compare the device IDs the driver supports with the
+ *	device IDs of the device. Note we don't do this ourselves
+ *	because we don't know the format of the ID structures, nor what
+ *	is to be considered a match and what is not.
+ *
+ *	If we find a match, we call @drv->probe(@dev) if it exists, and
+ *	call device_bind_driver() above.
+ */
+int driver_probe_device(struct device_driver * drv, struct device * dev)
+{
+	int error = 0;
+
+	if (drv->bus->match && !drv->bus->match(dev, drv))
+		return -ENODEV;
+
+	down(&dev->sem);
+	dev->driver = drv;
+	if (drv->probe) {
+		error = drv->probe(dev);
+		if (error) {
+			dev->driver = NULL;
+			up(&dev->sem);
+			return error;
+		}
+	}
+	up(&dev->sem);
+	device_bind_driver(dev);
+	return 0;
+}
+
+/**
+ *	device_attach - try to attach device to a driver.
+ *	@dev:	device.
+ *
+ *	Walk the list of drivers that the bus has and call
+ *	driver_probe_device() for each pair. If a compatible
+ *	pair is found, break out and return.
+ */
+int device_attach(struct device * dev)
+{
+ 	struct bus_type * bus = dev->bus;
+	struct list_head * entry;
+	int error;
+
+	if (dev->driver) {
+		device_bind_driver(dev);
+		return 1;
+	}
+
+	if (bus->match) {
+		list_for_each(entry, &bus->drivers.list) {
+			struct device_driver * drv = to_drv(entry);
+			error = driver_probe_device(drv, dev);
+			if (!error)
+				/* success, driver matched */
+				return 1;
+			if (error != -ENODEV && error != -ENXIO)
+				/* driver matched but the probe failed */
+				printk(KERN_WARNING
+				    "%s: probe of %s failed with error %d\n",
+				    drv->name, dev->bus_id, error);
+		}
+	}
+
+	return 0;
+}
+
+/**
+ *	driver_attach - try to bind driver to devices.
+ *	@drv:	driver.
+ *
+ *	Walk the list of devices that the bus has on it and try to
+ *	match the driver with each one.  If driver_probe_device()
+ *	returns 0 and the @dev->driver is set, we've found a
+ *	compatible pair.
+ *
+ *	Note that we ignore the -ENODEV error from driver_probe_device(),
+ *	since it's perfectly valid for a driver not to bind to any devices.
+ */
+void driver_attach(struct device_driver * drv)
+{
+	struct bus_type * bus = drv->bus;
+	struct list_head * entry;
+	int error;
+
+	if (!bus->match)
+		return;
+
+	list_for_each(entry, &bus->devices.list) {
+		struct device * dev = container_of(entry, struct device, bus_list);
+		if (!dev->driver) {
+			error = driver_probe_device(drv, dev);
+			if (error && (error != -ENODEV))
+				/* driver matched but the probe failed */
+				printk(KERN_WARNING
+				    "%s: probe of %s failed with error %d\n",
+				    drv->name, dev->bus_id, error);
+		}
+	}
+}
+
+/**
+ *	device_release_driver - manually detach device from driver.
+ *	@dev:	device.
+ *
+ *	Manually detach device from driver.
+ *	Note that this is called without incrementing the bus
+ *	reference count nor taking the bus's rwsem. Be sure that
+ *	those are accounted for before calling this function.
+ */
+void device_release_driver(struct device * dev)
+{
+	struct device_driver * drv;
+
+	down(&dev->sem);
+	drv = dev->driver;
+	if (drv) {
+		sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj));
+		sysfs_remove_link(&dev->kobj, "driver");
+		list_del_init(&dev->driver_list);
+		if (drv->remove)
+			drv->remove(dev);
+		dev->driver = NULL;
+	}
+	up(&dev->sem);
+}
+
+/**
+ * driver_detach - detach driver from all devices it controls.
+ * @drv: driver.
+ */
+void driver_detach(struct device_driver * drv)
+{
+	while (!list_empty(&drv->devices)) {
+		struct device * dev = container_of(drv->devices.next, struct device, driver_list);
+		device_release_driver(dev);
+	}
+}
+
+
+EXPORT_SYMBOL_GPL(driver_probe_device);
+EXPORT_SYMBOL_GPL(device_bind_driver);
+EXPORT_SYMBOL_GPL(device_release_driver);
+EXPORT_SYMBOL_GPL(device_attach);
+EXPORT_SYMBOL_GPL(driver_attach);
+