EXPORT_SYMBOL_GPL(device_show_bool);
/**
- * device_release - free device structure.
- * @kobj: device's kobject.
+ * device_release - free device structure.
+ * @kobj: device's kobject.
*
- * This is called once the reference count for the object
- * reaches 0. We forward the call to the device's release
- * method, which should handle actually freeing the structure.
+ * This is called once the reference count for the object
+ * reaches 0. We forward the call to the device's release
+ * method, which should handle actually freeing the structure.
*/
static void device_release(struct kobject *kobj)
{
static struct device_attribute uevent_attr =
__ATTR(uevent, S_IRUGO | S_IWUSR, show_uevent, store_uevent);
+static ssize_t show_online(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ bool val;
+
+ lock_device_hotplug();
+ val = !dev->offline;
+ unlock_device_hotplug();
+ return sprintf(buf, "%u\n", val);
+}
+
+static ssize_t store_online(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ bool val;
+ int ret;
+
+ ret = strtobool(buf, &val);
+ if (ret < 0)
+ return ret;
+
+ lock_device_hotplug();
+ ret = val ? device_online(dev) : device_offline(dev);
+ unlock_device_hotplug();
+ return ret < 0 ? ret : count;
+}
+
+static struct device_attribute online_attr =
+ __ATTR(online, S_IRUGO | S_IWUSR, show_online, store_online);
+
static int device_add_attributes(struct device *dev,
struct device_attribute *attrs)
{
if (error)
goto err_remove_type_groups;
+ if (device_supports_offline(dev) && !dev->offline_disabled) {
+ error = device_create_file(dev, &online_attr);
+ if (error)
+ goto err_remove_type_groups;
+ }
+
return 0;
err_remove_type_groups:
struct class *class = dev->class;
const struct device_type *type = dev->type;
+ device_remove_file(dev, &online_attr);
device_remove_groups(dev, dev->groups);
if (type)
/**
* device_for_each_child - device child iterator.
* @parent: parent struct device.
- * @data: data for the callback.
* @fn: function to be called for each device.
+ * @data: data for the callback.
*
* Iterate over @parent's child devices, and call @fn for each,
* passing it @data.
/**
* device_find_child - device iterator for locating a particular device.
* @parent: parent struct device
- * @data: Data to pass to match function
* @match: Callback function to check device
+ * @data: Data to pass to match function
*
* This is similar to the device_for_each_child() function above, but it
* returns a reference to a device that is 'found' for later use, as
* if it does. If the callback returns non-zero and a reference to the
* current device can be obtained, this function will return to the caller
* and not iterate over any more devices.
+ *
+ * NOTE: you will need to drop the reference with put_device() after use.
*/
struct device *device_find_child(struct device *parent, void *data,
int (*match)(struct device *dev, void *data))
EXPORT_SYMBOL_GPL(device_create_file);
EXPORT_SYMBOL_GPL(device_remove_file);
+static DEFINE_MUTEX(device_hotplug_lock);
+
+void lock_device_hotplug(void)
+{
+ mutex_lock(&device_hotplug_lock);
+}
+
+void unlock_device_hotplug(void)
+{
+ mutex_unlock(&device_hotplug_lock);
+}
+
+static int device_check_offline(struct device *dev, void *not_used)
+{
+ int ret;
+
+ ret = device_for_each_child(dev, NULL, device_check_offline);
+ if (ret)
+ return ret;
+
+ return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0;
+}
+
+/**
+ * device_offline - Prepare the device for hot-removal.
+ * @dev: Device to be put offline.
+ *
+ * Execute the device bus type's .offline() callback, if present, to prepare
+ * the device for a subsequent hot-removal. If that succeeds, the device must
+ * not be used until either it is removed or its bus type's .online() callback
+ * is executed.
+ *
+ * Call under device_hotplug_lock.
+ */
+int device_offline(struct device *dev)
+{
+ int ret;
+
+ if (dev->offline_disabled)
+ return -EPERM;
+
+ ret = device_for_each_child(dev, NULL, device_check_offline);
+ if (ret)
+ return ret;
+
+ device_lock(dev);
+ if (device_supports_offline(dev)) {
+ if (dev->offline) {
+ ret = 1;
+ } else {
+ ret = dev->bus->offline(dev);
+ if (!ret) {
+ kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
+ dev->offline = true;
+ }
+ }
+ }
+ device_unlock(dev);
+
+ return ret;
+}
+
+/**
+ * device_online - Put the device back online after successful device_offline().
+ * @dev: Device to be put back online.
+ *
+ * If device_offline() has been successfully executed for @dev, but the device
+ * has not been removed subsequently, execute its bus type's .online() callback
+ * to indicate that the device can be used again.
+ *
+ * Call under device_hotplug_lock.
+ */
+int device_online(struct device *dev)
+{
+ int ret = 0;
+
+ device_lock(dev);
+ if (device_supports_offline(dev)) {
+ if (dev->offline) {
+ ret = dev->bus->online(dev);
+ if (!ret) {
+ kobject_uevent(&dev->kobj, KOBJ_ONLINE);
+ dev->offline = false;
+ }
+ } else {
+ ret = 1;
+ }
+ }
+ device_unlock(dev);
+
+ return ret;
+}
+
struct root_device {
struct device dev;
struct module *owner;
projects / karo-tx-linux.git / blobdiff