[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 000000000000..b709b1e0cb2a
--- /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);
+