devres: device resource management
[safe/jmp/linux-2.6] / drivers / base / bus.c
index 1b05c13..472810f 100644 (file)
@@ -8,7 +8,6 @@
  *
  */
 
-#include <linux/config.h>
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/errno.h>
@@ -17,8 +16,6 @@
 #include "base.h"
 #include "power/power.h"
 
-#define to_dev(node) container_of(node, struct device, bus_list)
-
 #define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
 #define to_bus(obj) container_of(obj, struct bus_type, subsys.kset.kobj)
 
@@ -132,52 +129,82 @@ static struct kobj_type ktype_bus = {
 
 };
 
-decl_subsys(bus, &ktype_bus, NULL);
+static decl_subsys(bus, &ktype_bus, NULL);
+
+
+#ifdef CONFIG_HOTPLUG
 
-static int __bus_for_each_dev(struct bus_type *bus, struct device *start,
-                             void *data, int (*fn)(struct device *, void *))
+/* Manually detach a device from its associated driver. */
+static int driver_helper(struct device *dev, void *data)
 {
-       struct list_head *head;
-       struct device *dev;
-       int error = 0;
+       const char *name = data;
 
-       if (!(bus = get_bus(bus)))
-               return -EINVAL;
+       if (strcmp(name, dev->bus_id) == 0)
+               return 1;
+       return 0;
+}
 
-       head = &bus->devices.list;
-       dev = list_prepare_entry(start, head, bus_list);
-       list_for_each_entry_continue(dev, head, bus_list) {
-               get_device(dev);
-               error = fn(dev, data);
-               put_device(dev);
-               if (error)
-                       break;
+static ssize_t driver_unbind(struct device_driver *drv,
+                            const char *buf, size_t count)
+{
+       struct bus_type *bus = get_bus(drv->bus);
+       struct device *dev;
+       int err = -ENODEV;
+
+       dev = bus_find_device(bus, NULL, (void *)buf, driver_helper);
+       if (dev && dev->driver == drv) {
+               if (dev->parent)        /* Needed for USB */
+                       down(&dev->parent->sem);
+               device_release_driver(dev);
+               if (dev->parent)
+                       up(&dev->parent->sem);
+               err = count;
        }
+       put_device(dev);
        put_bus(bus);
-       return error;
+       return err;
 }
+static DRIVER_ATTR(unbind, S_IWUSR, NULL, driver_unbind);
 
-static int __bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
-                             void * data, int (*fn)(struct device_driver *, void *))
+/*
+ * Manually attach a device to a driver.
+ * Note: the driver must want to bind to the device,
+ * it is not possible to override the driver's id table.
+ */
+static ssize_t driver_bind(struct device_driver *drv,
+                          const char *buf, size_t count)
 {
-       struct list_head *head;
-       struct device_driver *drv;
-       int error = 0;
-
-       if (!(bus = get_bus(bus)))
-               return -EINVAL;
-
-       head = &bus->drivers.list;
-       drv = list_prepare_entry(start, head, kobj.entry);
-       list_for_each_entry_continue(drv, head, kobj.entry) {
-               get_driver(drv);
-               error = fn(drv, data);
-               put_driver(drv);
-               if (error)
-                       break;
+       struct bus_type *bus = get_bus(drv->bus);
+       struct device *dev;
+       int err = -ENODEV;
+
+       dev = bus_find_device(bus, NULL, (void *)buf, driver_helper);
+       if (dev && dev->driver == NULL) {
+               if (dev->parent)        /* Needed for USB */
+                       down(&dev->parent->sem);
+               down(&dev->sem);
+               err = driver_probe_device(drv, dev);
+               up(&dev->sem);
+               if (dev->parent)
+                       up(&dev->parent->sem);
+
+               if (err > 0)            /* success */
+                       err = count;
+               else if (err == 0)      /* driver didn't accept device */
+                       err = -ENODEV;
        }
+       put_device(dev);
        put_bus(bus);
-       return error;
+       return err;
+}
+static DRIVER_ATTR(bind, S_IWUSR, NULL, driver_bind);
+
+#endif
+
+static struct device * next_device(struct klist_iter * i)
+{
+       struct klist_node * n = klist_next(i);
+       return n ? container_of(n, struct device, knode_bus) : NULL;
 }
 
 /**
@@ -203,12 +230,60 @@ static int __bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
 int bus_for_each_dev(struct bus_type * bus, struct device * start,
                     void * data, int (*fn)(struct device *, void *))
 {
-       int ret;
+       struct klist_iter i;
+       struct device * dev;
+       int error = 0;
 
-       down_read(&bus->subsys.rwsem);
-       ret = __bus_for_each_dev(bus, start, data, fn);
-       up_read(&bus->subsys.rwsem);
-       return ret;
+       if (!bus)
+               return -EINVAL;
+
+       klist_iter_init_node(&bus->klist_devices, &i,
+                            (start ? &start->knode_bus : NULL));
+       while ((dev = next_device(&i)) && !error)
+               error = fn(dev, data);
+       klist_iter_exit(&i);
+       return error;
+}
+
+/**
+ * bus_find_device - device iterator for locating a particular device.
+ * @bus: bus type
+ * @start: Device to begin with
+ * @data: Data to pass to match function
+ * @match: Callback function to check device
+ *
+ * This is similar to the bus_for_each_dev() function above, but it
+ * returns a reference to a device that is 'found' for later use, as
+ * determined by the @match callback.
+ *
+ * The callback should return 0 if the device doesn't match and non-zero
+ * if it does.  If the callback returns non-zero, this function will
+ * return to the caller and not iterate over any more devices.
+ */
+struct device * bus_find_device(struct bus_type *bus,
+                               struct device *start, void *data,
+                               int (*match)(struct device *, void *))
+{
+       struct klist_iter i;
+       struct device *dev;
+
+       if (!bus)
+               return NULL;
+
+       klist_iter_init_node(&bus->klist_devices, &i,
+                            (start ? &start->knode_bus : NULL));
+       while ((dev = next_device(&i)))
+               if (match(dev, data) && get_device(dev))
+                       break;
+       klist_iter_exit(&i);
+       return dev;
+}
+
+
+static struct device_driver * next_driver(struct klist_iter * i)
+{
+       struct klist_node * n = klist_next(i);
+       return n ? container_of(n, struct device_driver, knode_bus) : NULL;
 }
 
 /**
@@ -234,12 +309,19 @@ int bus_for_each_dev(struct bus_type * bus, struct device * start,
 int bus_for_each_drv(struct bus_type * bus, struct device_driver * start,
                     void * data, int (*fn)(struct device_driver *, void *))
 {
-       int ret;
+       struct klist_iter i;
+       struct device_driver * drv;
+       int error = 0;
 
-       down_read(&bus->subsys.rwsem);
-       ret = __bus_for_each_drv(bus, start, data, fn);
-       up_read(&bus->subsys.rwsem);
-       return ret;
+       if (!bus)
+               return -EINVAL;
+
+       klist_iter_init_node(&bus->klist_drivers, &i,
+                            start ? &start->knode_bus : NULL);
+       while ((drv = next_driver(&i)) && !error)
+               error = fn(drv, data);
+       klist_iter_exit(&i);
+       return error;
 }
 
 static int device_add_attrs(struct bus_type * bus, struct device * dev)
@@ -273,14 +355,28 @@ static void device_remove_attrs(struct bus_type * bus, struct device * dev)
        }
 }
 
+#ifdef CONFIG_SYSFS_DEPRECATED
+static int make_deprecated_bus_links(struct device *dev)
+{
+       return sysfs_create_link(&dev->kobj,
+                                &dev->bus->subsys.kset.kobj, "bus");
+}
+
+static void remove_deprecated_bus_links(struct device *dev)
+{
+       sysfs_remove_link(&dev->kobj, "bus");
+}
+#else
+static inline int make_deprecated_bus_links(struct device *dev) { return 0; }
+static inline void remove_deprecated_bus_links(struct device *dev) { }
+#endif
 
 /**
  *     bus_add_device - add device to bus
  *     @dev:   device being added
  *
  *     - Add the device to its bus's list of devices.
- *     - Try to attach to driver.
- *     - Create link to device's physical location.
+ *     - Create link to device's bus.
  */
 int bus_add_device(struct device * dev)
 {
@@ -288,19 +384,60 @@ int bus_add_device(struct device * dev)
        int error = 0;
 
        if (bus) {
-               down_write(&dev->bus->subsys.rwsem);
                pr_debug("bus %s: add device %s\n", bus->name, dev->bus_id);
-               list_add_tail(&dev->bus_list, &dev->bus->devices.list);
-               device_attach(dev);
-               up_write(&dev->bus->subsys.rwsem);
-               device_add_attrs(bus, dev);
-               sysfs_create_link(&bus->devices.kobj, &dev->kobj, dev->bus_id);
-               sysfs_create_link(&dev->kobj, &dev->bus->subsys.kset.kobj, "bus");
+               error = device_add_attrs(bus, dev);
+               if (error)
+                       goto out_put;
+               error = sysfs_create_link(&bus->devices.kobj,
+                                               &dev->kobj, dev->bus_id);
+               if (error)
+                       goto out_id;
+               error = sysfs_create_link(&dev->kobj,
+                               &dev->bus->subsys.kset.kobj, "subsystem");
+               if (error)
+                       goto out_subsys;
+               error = make_deprecated_bus_links(dev);
+               if (error)
+                       goto out_deprecated;
        }
+       return 0;
+
+out_deprecated:
+       sysfs_remove_link(&dev->kobj, "subsystem");
+out_subsys:
+       sysfs_remove_link(&bus->devices.kobj, dev->bus_id);
+out_id:
+       device_remove_attrs(bus, dev);
+out_put:
+       put_bus(dev->bus);
        return error;
 }
 
 /**
+ *     bus_attach_device - add device to bus
+ *     @dev:   device tried to attach to a driver
+ *
+ *     - Add device to bus's list of devices.
+ *     - Try to attach to driver.
+ */
+int bus_attach_device(struct device * dev)
+{
+       struct bus_type *bus = dev->bus;
+       int ret = 0;
+
+       if (bus) {
+               dev->is_registered = 1;
+               ret = device_attach(dev);
+               if (ret >= 0) {
+                       klist_add_tail(&dev->knode_bus, &bus->klist_devices);
+                       ret = 0;
+               } else
+                       dev->is_registered = 0;
+       }
+       return ret;
+}
+
+/**
  *     bus_remove_device - remove device from bus
  *     @dev:   device to be removed
  *
@@ -312,14 +449,16 @@ int bus_add_device(struct device * dev)
 void bus_remove_device(struct device * dev)
 {
        if (dev->bus) {
-               sysfs_remove_link(&dev->kobj, "bus");
+               sysfs_remove_link(&dev->kobj, "subsystem");
+               remove_deprecated_bus_links(dev);
                sysfs_remove_link(&dev->bus->devices.kobj, dev->bus_id);
                device_remove_attrs(dev->bus, dev);
-               down_write(&dev->bus->subsys.rwsem);
+               if (dev->is_registered) {
+                       dev->is_registered = 0;
+                       klist_del(&dev->knode_bus);
+               }
                pr_debug("bus %s: remove device %s\n", dev->bus->name, dev->bus_id);
                device_release_driver(dev);
-               list_del_init(&dev->bus_list);
-               up_write(&dev->bus->subsys.rwsem);
                put_bus(dev->bus);
        }
 }
@@ -355,41 +494,82 @@ static void driver_remove_attrs(struct bus_type * bus, struct device_driver * dr
        }
 }
 
+#ifdef CONFIG_HOTPLUG
+/*
+ * Thanks to drivers making their tables __devinit, we can't allow manual
+ * bind and unbind from userspace unless CONFIG_HOTPLUG is enabled.
+ */
+static int __must_check add_bind_files(struct device_driver *drv)
+{
+       int ret;
+
+       ret = driver_create_file(drv, &driver_attr_unbind);
+       if (ret == 0) {
+               ret = driver_create_file(drv, &driver_attr_bind);
+               if (ret)
+                       driver_remove_file(drv, &driver_attr_unbind);
+       }
+       return ret;
+}
+
+static void remove_bind_files(struct device_driver *drv)
+{
+       driver_remove_file(drv, &driver_attr_bind);
+       driver_remove_file(drv, &driver_attr_unbind);
+}
+#else
+static inline int add_bind_files(struct device_driver *drv) { return 0; }
+static inline void remove_bind_files(struct device_driver *drv) {}
+#endif
 
 /**
  *     bus_add_driver - Add a driver to the bus.
  *     @drv:   driver.
  *
  */
-int bus_add_driver(struct device_driver * drv)
+int bus_add_driver(struct device_driver *drv)
 {
        struct bus_type * bus = get_bus(drv->bus);
        int error = 0;
 
-       if (bus) {
-               pr_debug("bus %s: add driver %s\n", bus->name, drv->name);
-               error = kobject_set_name(&drv->kobj, "%s", drv->name);
-               if (error) {
-                       put_bus(bus);
-                       return error;
-               }
-               drv->kobj.kset = &bus->drivers;
-               if ((error = kobject_register(&drv->kobj))) {
-                       put_bus(bus);
-                       return error;
-               }
-
-               down_write(&bus->subsys.rwsem);
-               driver_attach(drv);
-               up_write(&bus->subsys.rwsem);
-               module_add_driver(drv->owner, drv);
-
-               driver_add_attrs(bus, drv);
+       if (!bus)
+               return 0;
+
+       pr_debug("bus %s: add driver %s\n", bus->name, drv->name);
+       error = kobject_set_name(&drv->kobj, "%s", drv->name);
+       if (error)
+               goto out_put_bus;
+       drv->kobj.kset = &bus->drivers;
+       if ((error = kobject_register(&drv->kobj)))
+               goto out_put_bus;
+
+       error = driver_attach(drv);
+       if (error)
+               goto out_unregister;
+       klist_add_tail(&drv->knode_bus, &bus->klist_drivers);
+       module_add_driver(drv->owner, drv);
+
+       error = driver_add_attrs(bus, drv);
+       if (error) {
+               /* How the hell do we get out of this pickle? Give up */
+               printk(KERN_ERR "%s: driver_add_attrs(%s) failed\n",
+                       __FUNCTION__, drv->name);
+       }
+       error = add_bind_files(drv);
+       if (error) {
+               /* Ditto */
+               printk(KERN_ERR "%s: add_bind_files(%s) failed\n",
+                       __FUNCTION__, drv->name);
        }
+
+       return error;
+out_unregister:
+       kobject_unregister(&drv->kobj);
+out_put_bus:
+       put_bus(bus);
        return error;
 }
 
-
 /**
  *     bus_remove_driver - delete driver from bus's knowledge.
  *     @drv:   driver.
@@ -401,55 +581,77 @@ int bus_add_driver(struct device_driver * drv)
 
 void bus_remove_driver(struct device_driver * drv)
 {
-       if (drv->bus) {
-               driver_remove_attrs(drv->bus, drv);
-               down_write(&drv->bus->subsys.rwsem);
-               pr_debug("bus %s: remove driver %s\n", drv->bus->name, drv->name);
-               driver_detach(drv);
-               up_write(&drv->bus->subsys.rwsem);
-               module_remove_driver(drv);
-               kobject_unregister(&drv->kobj);
-               put_bus(drv->bus);
-       }
+       if (!drv->bus)
+               return;
+
+       remove_bind_files(drv);
+       driver_remove_attrs(drv->bus, drv);
+       klist_remove(&drv->knode_bus);
+       pr_debug("bus %s: remove driver %s\n", drv->bus->name, drv->name);
+       driver_detach(drv);
+       module_remove_driver(drv);
+       kobject_unregister(&drv->kobj);
+       put_bus(drv->bus);
 }
 
 
 /* Helper for bus_rescan_devices's iter */
-static int bus_rescan_devices_helper(struct device *dev, void *data)
+static int __must_check bus_rescan_devices_helper(struct device *dev,
+                                               void *data)
 {
-       int *count = data;
-
-       if (!dev->driver && device_attach(dev))
-               (*count)++;
-
-       return 0;
+       int ret = 0;
+
+       if (!dev->driver) {
+               if (dev->parent)        /* Needed for USB */
+                       down(&dev->parent->sem);
+               ret = device_attach(dev);
+               if (dev->parent)
+                       up(&dev->parent->sem);
+               if (ret > 0)
+                       ret = 0;
+       }
+       return ret < 0 ? ret : 0;
 }
 
-
 /**
- *     bus_rescan_devices - rescan devices on the bus for possible drivers
- *     @bus:   the bus to scan.
+ * bus_rescan_devices - rescan devices on the bus for possible drivers
+ * @bus: the bus to scan.
  *
- *     This function will look for devices on the bus with no driver
- *     attached and rescan it against existing drivers to see if it
- *     matches any. Calls device_attach(). Returns the number of devices
- *     that were sucessfully bound to a driver.
+ * This function will look for devices on the bus with no driver
+ * attached and rescan it against existing drivers to see if it matches
+ * any by calling device_attach() for the unbound devices.
  */
 int bus_rescan_devices(struct bus_type * bus)
 {
-       int count = 0;
-
-       down_write(&bus->subsys.rwsem);
-       __bus_for_each_dev(bus, NULL, &count, bus_rescan_devices_helper);
-       up_write(&bus->subsys.rwsem);
-
-       return count;
+       return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);
 }
 
+/**
+ * device_reprobe - remove driver for a device and probe for a new driver
+ * @dev: the device to reprobe
+ *
+ * This function detaches the attached driver (if any) for the given
+ * device and restarts the driver probing process.  It is intended
+ * to use if probing criteria changed during a devices lifetime and
+ * driver attachment should change accordingly.
+ */
+int device_reprobe(struct device *dev)
+{
+       if (dev->driver) {
+               if (dev->parent)        /* Needed for USB */
+                       down(&dev->parent->sem);
+               device_release_driver(dev);
+               if (dev->parent)
+                       up(&dev->parent->sem);
+       }
+       return bus_rescan_devices_helper(dev, NULL);
+}
+EXPORT_SYMBOL_GPL(device_reprobe);
 
-struct bus_type * get_bus(struct bus_type * bus)
+struct bus_type *get_bus(struct bus_type *bus)
 {
-       return bus ? container_of(subsys_get(&bus->subsys), struct bus_type, subsys) : NULL;
+       return bus ? container_of(subsys_get(&bus->subsys),
+                               struct bus_type, subsys) : NULL;
 }
 
 void put_bus(struct bus_type * bus)
@@ -467,12 +669,13 @@ void put_bus(struct bus_type * bus)
  *
  *     Note that kset_find_obj increments bus' reference count.
  */
-
+#if 0
 struct bus_type * find_bus(char * name)
 {
        struct kobject * k = kset_find_obj(&bus_subsys.kset, name);
        return k ? to_bus(k) : NULL;
 }
+#endif  /*  0  */
 
 
 /**
@@ -509,6 +712,20 @@ static void bus_remove_attrs(struct bus_type * bus)
        }
 }
 
+static void klist_devices_get(struct klist_node *n)
+{
+       struct device *dev = container_of(n, struct device, knode_bus);
+
+       get_device(dev);
+}
+
+static void klist_devices_put(struct klist_node *n)
+{
+       struct device *dev = container_of(n, struct device, knode_bus);
+
+       put_device(dev);
+}
+
 /**
  *     bus_register - register a bus with the system.
  *     @bus:   bus.
@@ -521,6 +738,8 @@ int bus_register(struct bus_type * bus)
 {
        int retval;
 
+       BLOCKING_INIT_NOTIFIER_HEAD(&bus->bus_notifier);
+
        retval = kobject_set_name(&bus->subsys.kset.kobj, "%s", bus->name);
        if (retval)
                goto out;
@@ -542,11 +761,18 @@ int bus_register(struct bus_type * bus)
        retval = kset_register(&bus->drivers);
        if (retval)
                goto bus_drivers_fail;
-       bus_add_attrs(bus);
+
+       klist_init(&bus->klist_devices, klist_devices_get, klist_devices_put);
+       klist_init(&bus->klist_drivers, NULL, NULL);
+       retval = bus_add_attrs(bus);
+       if (retval)
+               goto bus_attrs_fail;
 
        pr_debug("bus type '%s' registered\n", bus->name);
        return 0;
 
+bus_attrs_fail:
+       kset_unregister(&bus->drivers);
 bus_drivers_fail:
        kset_unregister(&bus->devices);
 bus_devices_fail:
@@ -572,6 +798,18 @@ void bus_unregister(struct bus_type * bus)
        subsystem_unregister(&bus->subsys);
 }
 
+int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)
+{
+       return blocking_notifier_chain_register(&bus->bus_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(bus_register_notifier);
+
+int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)
+{
+       return blocking_notifier_chain_unregister(&bus->bus_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(bus_unregister_notifier);
+
 int __init buses_init(void)
 {
        return subsystem_register(&bus_subsys);
@@ -579,16 +817,12 @@ int __init buses_init(void)
 
 
 EXPORT_SYMBOL_GPL(bus_for_each_dev);
+EXPORT_SYMBOL_GPL(bus_find_device);
 EXPORT_SYMBOL_GPL(bus_for_each_drv);
 
-EXPORT_SYMBOL_GPL(bus_add_device);
-EXPORT_SYMBOL_GPL(bus_remove_device);
 EXPORT_SYMBOL_GPL(bus_register);
 EXPORT_SYMBOL_GPL(bus_unregister);
 EXPORT_SYMBOL_GPL(bus_rescan_devices);
-EXPORT_SYMBOL_GPL(get_bus);
-EXPORT_SYMBOL_GPL(put_bus);
-EXPORT_SYMBOL_GPL(find_bus);
 
 EXPORT_SYMBOL_GPL(bus_create_file);
 EXPORT_SYMBOL_GPL(bus_remove_file);