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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/base/bus.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'drivers/base/bus.c')
-rw-r--r--drivers/base/bus.c770
1 files changed, 770 insertions, 0 deletions
diff --git a/drivers/base/bus.c b/drivers/base/bus.c
new file mode 100644
index 000000000000..f4fa27315fb4
--- /dev/null
+++ b/drivers/base/bus.c
@@ -0,0 +1,770 @@
+/*
+ * bus.c - bus driver management
+ *
+ * Copyright (c) 2002-3 Patrick Mochel
+ * Copyright (c) 2002-3 Open Source Development Labs
+ *
+ * This file is released under the GPLv2
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include "base.h"
+#include "power/power.h"
+
+#define to_dev(node) container_of(node, struct device, bus_list)
+#define to_drv(node) container_of(node, struct device_driver, kobj.entry)
+
+#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)
+
+/*
+ * sysfs bindings for drivers
+ */
+
+#define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr)
+#define to_driver(obj) container_of(obj, struct device_driver, kobj)
+
+
+static ssize_t
+drv_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
+{
+ struct driver_attribute * drv_attr = to_drv_attr(attr);
+ struct device_driver * drv = to_driver(kobj);
+ ssize_t ret = 0;
+
+ if (drv_attr->show)
+ ret = drv_attr->show(drv, buf);
+ return ret;
+}
+
+static ssize_t
+drv_attr_store(struct kobject * kobj, struct attribute * attr,
+ const char * buf, size_t count)
+{
+ struct driver_attribute * drv_attr = to_drv_attr(attr);
+ struct device_driver * drv = to_driver(kobj);
+ ssize_t ret = 0;
+
+ if (drv_attr->store)
+ ret = drv_attr->store(drv, buf, count);
+ return ret;
+}
+
+static struct sysfs_ops driver_sysfs_ops = {
+ .show = drv_attr_show,
+ .store = drv_attr_store,
+};
+
+
+static void driver_release(struct kobject * kobj)
+{
+ struct device_driver * drv = to_driver(kobj);
+ complete(&drv->unloaded);
+}
+
+static struct kobj_type ktype_driver = {
+ .sysfs_ops = &driver_sysfs_ops,
+ .release = driver_release,
+};
+
+
+/*
+ * sysfs bindings for buses
+ */
+
+
+static ssize_t
+bus_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
+{
+ struct bus_attribute * bus_attr = to_bus_attr(attr);
+ struct bus_type * bus = to_bus(kobj);
+ ssize_t ret = 0;
+
+ if (bus_attr->show)
+ ret = bus_attr->show(bus, buf);
+ return ret;
+}
+
+static ssize_t
+bus_attr_store(struct kobject * kobj, struct attribute * attr,
+ const char * buf, size_t count)
+{
+ struct bus_attribute * bus_attr = to_bus_attr(attr);
+ struct bus_type * bus = to_bus(kobj);
+ ssize_t ret = 0;
+
+ if (bus_attr->store)
+ ret = bus_attr->store(bus, buf, count);
+ return ret;
+}
+
+static struct sysfs_ops bus_sysfs_ops = {
+ .show = bus_attr_show,
+ .store = bus_attr_store,
+};
+
+int bus_create_file(struct bus_type * bus, struct bus_attribute * attr)
+{
+ int error;
+ if (get_bus(bus)) {
+ error = sysfs_create_file(&bus->subsys.kset.kobj, &attr->attr);
+ put_bus(bus);
+ } else
+ error = -EINVAL;
+ return error;
+}
+
+void bus_remove_file(struct bus_type * bus, struct bus_attribute * attr)
+{
+ if (get_bus(bus)) {
+ sysfs_remove_file(&bus->subsys.kset.kobj, &attr->attr);
+ put_bus(bus);
+ }
+}
+
+static struct kobj_type ktype_bus = {
+ .sysfs_ops = &bus_sysfs_ops,
+
+};
+
+decl_subsys(bus, &ktype_bus, NULL);
+
+static int __bus_for_each_dev(struct bus_type *bus, struct device *start,
+ void *data, int (*fn)(struct device *, void *))
+{
+ struct list_head *head;
+ struct device *dev;
+ int error = 0;
+
+ if (!(bus = get_bus(bus)))
+ return -EINVAL;
+
+ 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;
+ }
+ put_bus(bus);
+ return error;
+}
+
+static int __bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
+ void * data, int (*fn)(struct device_driver *, void *))
+{
+ 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;
+ }
+ put_bus(bus);
+ return error;
+}
+
+/**
+ * bus_for_each_dev - device iterator.
+ * @bus: bus type.
+ * @start: device to start iterating from.
+ * @data: data for the callback.
+ * @fn: function to be called for each device.
+ *
+ * Iterate over @bus's list of devices, and call @fn for each,
+ * passing it @data. If @start is not NULL, we use that device to
+ * begin iterating from.
+ *
+ * We check the return of @fn each time. If it returns anything
+ * other than 0, we break out and return that value.
+ *
+ * NOTE: The device that returns a non-zero value is not retained
+ * in any way, nor is its refcount incremented. If the caller needs
+ * to retain this data, it should do, and increment the reference
+ * count in the supplied callback.
+ */
+
+int bus_for_each_dev(struct bus_type * bus, struct device * start,
+ void * data, int (*fn)(struct device *, void *))
+{
+ int ret;
+
+ down_read(&bus->subsys.rwsem);
+ ret = __bus_for_each_dev(bus, start, data, fn);
+ up_read(&bus->subsys.rwsem);
+ return ret;
+}
+
+/**
+ * bus_for_each_drv - driver iterator
+ * @bus: bus we're dealing with.
+ * @start: driver to start iterating on.
+ * @data: data to pass to the callback.
+ * @fn: function to call for each driver.
+ *
+ * This is nearly identical to the device iterator above.
+ * We iterate over each driver that belongs to @bus, and call
+ * @fn for each. If @fn returns anything but 0, we break out
+ * and return it. If @start is not NULL, we use it as the head
+ * of the list.
+ *
+ * NOTE: we don't return the driver that returns a non-zero
+ * value, nor do we leave the reference count incremented for that
+ * driver. If the caller needs to know that info, it must set it
+ * in the callback. It must also be sure to increment the refcount
+ * so it doesn't disappear before returning to the caller.
+ */
+
+int bus_for_each_drv(struct bus_type * bus, struct device_driver * start,
+ void * data, int (*fn)(struct device_driver *, void *))
+{
+ int ret;
+
+ down_read(&bus->subsys.rwsem);
+ ret = __bus_for_each_drv(bus, start, data, fn);
+ up_read(&bus->subsys.rwsem);
+ return ret;
+}
+
+/**
+ * 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)
+{
+ if (drv->bus->match && !drv->bus->match(dev, drv))
+ return -ENODEV;
+
+ dev->driver = drv;
+ if (drv->probe) {
+ int error = drv->probe(dev);
+ if (error) {
+ dev->driver = NULL;
+ return error;
+ }
+ }
+
+ 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 = 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);
+ device_detach_shutdown(dev);
+ if (drv->remove)
+ drv->remove(dev);
+ dev->driver = NULL;
+ }
+}
+
+
+/**
+ * driver_detach - detach driver from all devices it controls.
+ * @drv: driver.
+ */
+
+static void driver_detach(struct device_driver * drv)
+{
+ struct list_head * entry, * next;
+ list_for_each_safe(entry, next, &drv->devices) {
+ struct device * dev = container_of(entry, struct device, driver_list);
+ device_release_driver(dev);
+ }
+}
+
+static int device_add_attrs(struct bus_type * bus, struct device * dev)
+{
+ int error = 0;
+ int i;
+
+ if (bus->dev_attrs) {
+ for (i = 0; attr_name(bus->dev_attrs[i]); i++) {
+ error = device_create_file(dev,&bus->dev_attrs[i]);
+ if (error)
+ goto Err;
+ }
+ }
+ Done:
+ return error;
+ Err:
+ while (--i >= 0)
+ device_remove_file(dev,&bus->dev_attrs[i]);
+ goto Done;
+}
+
+
+static void device_remove_attrs(struct bus_type * bus, struct device * dev)
+{
+ int i;
+
+ if (bus->dev_attrs) {
+ for (i = 0; attr_name(bus->dev_attrs[i]); i++)
+ device_remove_file(dev,&bus->dev_attrs[i]);
+ }
+}
+
+
+/**
+ * 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.
+ */
+int bus_add_device(struct device * dev)
+{
+ struct bus_type * bus = get_bus(dev->bus);
+ 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");
+ }
+ return error;
+}
+
+/**
+ * bus_remove_device - remove device from bus
+ * @dev: device to be removed
+ *
+ * - Remove symlink from bus's directory.
+ * - Delete device from bus's list.
+ * - Detach from its driver.
+ * - Drop reference taken in bus_add_device().
+ */
+void bus_remove_device(struct device * dev)
+{
+ if (dev->bus) {
+ sysfs_remove_link(&dev->kobj, "bus");
+ sysfs_remove_link(&dev->bus->devices.kobj, dev->bus_id);
+ device_remove_attrs(dev->bus, dev);
+ down_write(&dev->bus->subsys.rwsem);
+ 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);
+ }
+}
+
+static int driver_add_attrs(struct bus_type * bus, struct device_driver * drv)
+{
+ int error = 0;
+ int i;
+
+ if (bus->drv_attrs) {
+ for (i = 0; attr_name(bus->drv_attrs[i]); i++) {
+ error = driver_create_file(drv, &bus->drv_attrs[i]);
+ if (error)
+ goto Err;
+ }
+ }
+ Done:
+ return error;
+ Err:
+ while (--i >= 0)
+ driver_remove_file(drv, &bus->drv_attrs[i]);
+ goto Done;
+}
+
+
+static void driver_remove_attrs(struct bus_type * bus, struct device_driver * drv)
+{
+ int i;
+
+ if (bus->drv_attrs) {
+ for (i = 0; attr_name(bus->drv_attrs[i]); i++)
+ driver_remove_file(drv, &bus->drv_attrs[i]);
+ }
+}
+
+
+/**
+ * bus_add_driver - Add a driver to the bus.
+ * @drv: driver.
+ *
+ */
+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);
+ }
+ return error;
+}
+
+
+/**
+ * bus_remove_driver - delete driver from bus's knowledge.
+ * @drv: driver.
+ *
+ * Detach the driver from the devices it controls, and remove
+ * it from its bus's list of drivers. Finally, we drop the reference
+ * to the bus we took in bus_add_driver().
+ */
+
+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);
+ }
+}
+
+
+/* Helper for bus_rescan_devices's iter */
+static int bus_rescan_devices_helper(struct device *dev, void *data)
+{
+ int *count = data;
+
+ if (!dev->driver && device_attach(dev))
+ (*count)++;
+
+ return 0;
+}
+
+
+/**
+ * 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.
+ */
+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;
+}
+
+
+struct bus_type * get_bus(struct bus_type * bus)
+{
+ return bus ? container_of(subsys_get(&bus->subsys), struct bus_type, subsys) : NULL;
+}
+
+void put_bus(struct bus_type * bus)
+{
+ subsys_put(&bus->subsys);
+}
+
+
+/**
+ * find_bus - locate bus by name.
+ * @name: name of bus.
+ *
+ * Call kset_find_obj() to iterate over list of buses to
+ * find a bus by name. Return bus if found.
+ *
+ * Note that kset_find_obj increments bus' reference count.
+ */
+
+struct bus_type * find_bus(char * name)
+{
+ struct kobject * k = kset_find_obj(&bus_subsys.kset, name);
+ return k ? to_bus(k) : NULL;
+}
+
+
+/**
+ * bus_add_attrs - Add default attributes for this bus.
+ * @bus: Bus that has just been registered.
+ */
+
+static int bus_add_attrs(struct bus_type * bus)
+{
+ int error = 0;
+ int i;
+
+ if (bus->bus_attrs) {
+ for (i = 0; attr_name(bus->bus_attrs[i]); i++) {
+ if ((error = bus_create_file(bus,&bus->bus_attrs[i])))
+ goto Err;
+ }
+ }
+ Done:
+ return error;
+ Err:
+ while (--i >= 0)
+ bus_remove_file(bus,&bus->bus_attrs[i]);
+ goto Done;
+}
+
+static void bus_remove_attrs(struct bus_type * bus)
+{
+ int i;
+
+ if (bus->bus_attrs) {
+ for (i = 0; attr_name(bus->bus_attrs[i]); i++)
+ bus_remove_file(bus,&bus->bus_attrs[i]);
+ }
+}
+
+/**
+ * bus_register - register a bus with the system.
+ * @bus: bus.
+ *
+ * Once we have that, we registered the bus with the kobject
+ * infrastructure, then register the children subsystems it has:
+ * the devices and drivers that belong to the bus.
+ */
+int bus_register(struct bus_type * bus)
+{
+ int retval;
+
+ retval = kobject_set_name(&bus->subsys.kset.kobj, "%s", bus->name);
+ if (retval)
+ goto out;
+
+ subsys_set_kset(bus, bus_subsys);
+ retval = subsystem_register(&bus->subsys);
+ if (retval)
+ goto out;
+
+ kobject_set_name(&bus->devices.kobj, "devices");
+ bus->devices.subsys = &bus->subsys;
+ retval = kset_register(&bus->devices);
+ if (retval)
+ goto bus_devices_fail;
+
+ kobject_set_name(&bus->drivers.kobj, "drivers");
+ bus->drivers.subsys = &bus->subsys;
+ bus->drivers.ktype = &ktype_driver;
+ retval = kset_register(&bus->drivers);
+ if (retval)
+ goto bus_drivers_fail;
+ bus_add_attrs(bus);
+
+ pr_debug("bus type '%s' registered\n", bus->name);
+ return 0;
+
+bus_drivers_fail:
+ kset_unregister(&bus->devices);
+bus_devices_fail:
+ subsystem_unregister(&bus->subsys);
+out:
+ return retval;
+}
+
+
+/**
+ * bus_unregister - remove a bus from the system
+ * @bus: bus.
+ *
+ * Unregister the child subsystems and the bus itself.
+ * Finally, we call put_bus() to release the refcount
+ */
+void bus_unregister(struct bus_type * bus)
+{
+ pr_debug("bus %s: unregistering\n", bus->name);
+ bus_remove_attrs(bus);
+ kset_unregister(&bus->drivers);
+ kset_unregister(&bus->devices);
+ subsystem_unregister(&bus->subsys);
+}
+
+int __init buses_init(void)
+{
+ return subsystem_register(&bus_subsys);
+}
+
+
+EXPORT_SYMBOL_GPL(bus_for_each_dev);
+EXPORT_SYMBOL_GPL(bus_for_each_drv);
+
+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);
+
+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);