1 files changed, 120 insertions, 0 deletions
diff --git a/drivers/usb/core/notify.c b/drivers/usb/core/notify.c
new file mode 100644
index 000000000000..37da059eced7
--- /dev/null
+++ b/drivers/usb/core/notify.c
@@ -0,0 +1,120 @@
+/*
+ * All the USB notify logic
+ *
+ * (C) Copyright 2005 Greg Kroah-Hartman <gregkh@suse.de>
+ *
+ * notifier functions originally based on those in kernel/sys.c
+ * but fixed up to not be so broken.
+ *
+ */
+
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/notifier.h>
+#ifdef CONFIG_USB_DEBUG
+	#define DEBUG
+#else
+	#undef DEBUG
+#endif
+#include <linux/usb.h>
+
+#include "usb.h"
+
+
+static struct notifier_block *usb_notifier_list;
+static DECLARE_MUTEX(usb_notifier_lock);
+
+static void usb_notifier_chain_register(struct notifier_block **list,
+					struct notifier_block *n)
+{
+	down(&usb_notifier_lock);
+	while (*list) {
+		if (n->priority > (*list)->priority)
+			break;
+		list = &((*list)->next);
+	}
+	n->next = *list;
+	*list = n;
+	up(&usb_notifier_lock);
+}
+
+static void usb_notifier_chain_unregister(struct notifier_block **nl,
+				   struct notifier_block *n)
+{
+	down(&usb_notifier_lock);
+	while ((*nl)!=NULL) {
+		if ((*nl)==n) {
+			*nl = n->next;
+			goto exit;
+		}
+		nl=&((*nl)->next);
+	}
+exit:
+	up(&usb_notifier_lock);
+}
+
+static int usb_notifier_call_chain(struct notifier_block **n,
+				   unsigned long val, void *v)
+{
+	int ret=NOTIFY_DONE;
+	struct notifier_block *nb = *n;
+
+	down(&usb_notifier_lock);
+	while (nb) {
+		ret = nb->notifier_call(nb,val,v);
+		if (ret&NOTIFY_STOP_MASK) {
+			goto exit;
+		}
+		nb = nb->next;
+	}
+exit:
+	up(&usb_notifier_lock);
+	return ret;
+}
+
+/**
+ * usb_register_notify - register a notifier callback whenever a usb change happens
+ * @nb: pointer to the notifier block for the callback events.
+ *
+ * These changes are either USB devices or busses being added or removed.
+ */
+void usb_register_notify(struct notifier_block *nb)
+{
+	usb_notifier_chain_register(&usb_notifier_list, nb);
+}
+EXPORT_SYMBOL_GPL(usb_register_notify);
+
+/**
+ * usb_unregister_notify - unregister a notifier callback
+ * @nb: pointer to the notifier block for the callback events.
+ *
+ * usb_register_notifier() must have been previously called for this function
+ * to work properly.
+ */
+void usb_unregister_notify(struct notifier_block *nb)
+{
+	usb_notifier_chain_unregister(&usb_notifier_list, nb);
+}
+EXPORT_SYMBOL_GPL(usb_unregister_notify);
+
+
+void usb_notify_add_device(struct usb_device *udev)
+{
+	usb_notifier_call_chain(&usb_notifier_list, USB_DEVICE_ADD, udev);
+}
+
+void usb_notify_remove_device(struct usb_device *udev)
+{
+	usb_notifier_call_chain(&usb_notifier_list, USB_DEVICE_REMOVE, udev);
+}
+
+void usb_notify_add_bus(struct usb_bus *ubus)
+{
+	usb_notifier_call_chain(&usb_notifier_list, USB_BUS_ADD, ubus);
+}
+
+void usb_notify_remove_bus(struct usb_bus *ubus)
+{
+	usb_notifier_call_chain(&usb_notifier_list, USB_BUS_REMOVE, ubus);
+}