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path: root/drivers/base/bus.c
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Diffstat (limited to 'drivers/base/bus.c')
-rw-r--r--drivers/base/bus.c112
1 files changed, 96 insertions, 16 deletions
diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 253868e03c70..1d76e2349654 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -27,6 +27,9 @@
#define to_driver(obj) container_of(obj, struct device_driver, kobj)
+static int __must_check bus_rescan_devices_helper(struct device *dev,
+ void *data);
+
static ssize_t
drv_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
{
@@ -60,8 +63,19 @@ static struct sysfs_ops driver_sysfs_ops = {
static void driver_release(struct kobject * kobj)
{
- struct device_driver * drv = to_driver(kobj);
- complete(&drv->unloaded);
+ /*
+ * Yes this is an empty release function, it is this way because struct
+ * device is always a static object, not a dynamic one. Yes, this is
+ * not nice and bad, but remember, drivers are code, reference counted
+ * by the module count, not a device, which is really data. And yes,
+ * in the future I do want to have all drivers be created dynamically,
+ * and am working toward that goal, but it will take a bit longer...
+ *
+ * But do not let this example give _anyone_ the idea that they can
+ * create a release function without any code in it at all, to do that
+ * is almost always wrong. If you have any questions about this,
+ * please send an email to <greg@kroah.com>
+ */
}
static struct kobj_type ktype_driver = {
@@ -133,7 +147,6 @@ static decl_subsys(bus, &ktype_bus, NULL);
#ifdef CONFIG_HOTPLUG
-
/* Manually detach a device from its associated driver. */
static int driver_helper(struct device *dev, void *data)
{
@@ -199,6 +212,33 @@ static ssize_t driver_bind(struct device_driver *drv,
}
static DRIVER_ATTR(bind, S_IWUSR, NULL, driver_bind);
+static ssize_t show_drivers_autoprobe(struct bus_type *bus, char *buf)
+{
+ return sprintf(buf, "%d\n", bus->drivers_autoprobe);
+}
+
+static ssize_t store_drivers_autoprobe(struct bus_type *bus,
+ const char *buf, size_t count)
+{
+ if (buf[0] == '0')
+ bus->drivers_autoprobe = 0;
+ else
+ bus->drivers_autoprobe = 1;
+ return count;
+}
+
+static ssize_t store_drivers_probe(struct bus_type *bus,
+ const char *buf, size_t count)
+{
+ struct device *dev;
+
+ dev = bus_find_device(bus, NULL, (void *)buf, driver_helper);
+ if (!dev)
+ return -ENODEV;
+ if (bus_rescan_devices_helper(dev, NULL) != 0)
+ return -EINVAL;
+ return count;
+}
#endif
static struct device * next_device(struct klist_iter * i)
@@ -418,21 +458,21 @@ out_put:
* - Add device to bus's list of devices.
* - Try to attach to driver.
*/
-int bus_attach_device(struct device * dev)
+void 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) {
+ if (bus->drivers_autoprobe)
+ ret = device_attach(dev);
+ WARN_ON(ret < 0);
+ if (ret >= 0)
klist_add_tail(&dev->knode_bus, &bus->klist_devices);
- ret = 0;
- } else
+ else
dev->is_registered = 0;
}
- return ret;
}
/**
@@ -515,9 +555,41 @@ static void remove_bind_files(struct device_driver *drv)
driver_remove_file(drv, &driver_attr_bind);
driver_remove_file(drv, &driver_attr_unbind);
}
+
+static int add_probe_files(struct bus_type *bus)
+{
+ int retval;
+
+ bus->drivers_probe_attr.attr.name = "drivers_probe";
+ bus->drivers_probe_attr.attr.mode = S_IWUSR;
+ bus->drivers_probe_attr.attr.owner = bus->owner;
+ bus->drivers_probe_attr.store = store_drivers_probe;
+ retval = bus_create_file(bus, &bus->drivers_probe_attr);
+ if (retval)
+ goto out;
+
+ bus->drivers_autoprobe_attr.attr.name = "drivers_autoprobe";
+ bus->drivers_autoprobe_attr.attr.mode = S_IWUSR | S_IRUGO;
+ bus->drivers_autoprobe_attr.attr.owner = bus->owner;
+ bus->drivers_autoprobe_attr.show = show_drivers_autoprobe;
+ bus->drivers_autoprobe_attr.store = store_drivers_autoprobe;
+ retval = bus_create_file(bus, &bus->drivers_autoprobe_attr);
+ if (retval)
+ bus_remove_file(bus, &bus->drivers_probe_attr);
+out:
+ return retval;
+}
+
+static void remove_probe_files(struct bus_type *bus)
+{
+ bus_remove_file(bus, &bus->drivers_autoprobe_attr);
+ bus_remove_file(bus, &bus->drivers_probe_attr);
+}
#else
static inline int add_bind_files(struct device_driver *drv) { return 0; }
static inline void remove_bind_files(struct device_driver *drv) {}
+static inline int add_probe_files(struct bus_type *bus) { return 0; }
+static inline void remove_probe_files(struct bus_type *bus) {}
#endif
/**
@@ -531,7 +603,7 @@ int bus_add_driver(struct device_driver *drv)
int error = 0;
if (!bus)
- return 0;
+ return -EINVAL;
pr_debug("bus %s: add driver %s\n", bus->name, drv->name);
error = kobject_set_name(&drv->kobj, "%s", drv->name);
@@ -541,9 +613,11 @@ int bus_add_driver(struct device_driver *drv)
if ((error = kobject_register(&drv->kobj)))
goto out_put_bus;
- error = driver_attach(drv);
- if (error)
- goto out_unregister;
+ if (drv->bus->drivers_autoprobe) {
+ error = driver_attach(drv);
+ if (error)
+ goto out_unregister;
+ }
klist_add_tail(&drv->knode_bus, &bus->klist_drivers);
module_add_driver(drv->owner, drv);
@@ -605,8 +679,6 @@ static int __must_check bus_rescan_devices_helper(struct device *dev,
ret = device_attach(dev);
if (dev->parent)
up(&dev->parent->sem);
- if (ret > 0)
- ret = 0;
}
return ret < 0 ? ret : 0;
}
@@ -762,6 +834,12 @@ int bus_register(struct bus_type * bus)
klist_init(&bus->klist_devices, klist_devices_get, klist_devices_put);
klist_init(&bus->klist_drivers, NULL, NULL);
+
+ bus->drivers_autoprobe = 1;
+ retval = add_probe_files(bus);
+ if (retval)
+ goto bus_probe_files_fail;
+
retval = bus_add_attrs(bus);
if (retval)
goto bus_attrs_fail;
@@ -770,6 +848,8 @@ int bus_register(struct bus_type * bus)
return 0;
bus_attrs_fail:
+ remove_probe_files(bus);
+bus_probe_files_fail:
kset_unregister(&bus->drivers);
bus_drivers_fail:
kset_unregister(&bus->devices);
@@ -779,7 +859,6 @@ out:
return retval;
}
-
/**
* bus_unregister - remove a bus from the system
* @bus: bus.
@@ -791,6 +870,7 @@ void bus_unregister(struct bus_type * bus)
{
pr_debug("bus %s: unregistering\n", bus->name);
bus_remove_attrs(bus);
+ remove_probe_files(bus);
kset_unregister(&bus->drivers);
kset_unregister(&bus->devices);
subsystem_unregister(&bus->subsys);