+#ifdef CONFIG_HOTPLUG
+
+/*
+ * This sends an uevent to userspace, typically helping to load driver
+ * or other modules, configure the device, and more. Drivers can provide
+ * a MODULE_DEVICE_TABLE to help with module loading subtasks.
+ *
+ * We're called either from khubd (the typical case) or from root hub
+ * (init, kapmd, modprobe, rmmod, etc), but the agents need to handle
+ * delays in event delivery. Use sysfs (and DEVPATH) to make sure the
+ * device (and this configuration!) are still present.
+ */
+static int usb_uevent(struct device *dev, char **envp, int num_envp,
+ char *buffer, int buffer_size)
+{
+ struct usb_interface *intf;
+ struct usb_device *usb_dev;
+ struct usb_host_interface *alt;
+ int i = 0;
+ int length = 0;
+
+ if (!dev)
+ return -ENODEV;
+
+ /* driver is often null here; dev_dbg() would oops */
+ pr_debug ("usb %s: uevent\n", dev->bus_id);
+
+ /* Must check driver_data here, as on remove driver is always NULL */
+ if ((dev->driver == &usb_generic_driver) ||
+ (dev->driver_data == &usb_generic_driver_data))
+ return 0;
+
+ intf = to_usb_interface(dev);
+ usb_dev = interface_to_usbdev (intf);
+ alt = intf->cur_altsetting;
+
+ if (usb_dev->devnum < 0) {
+ pr_debug ("usb %s: already deleted?\n", dev->bus_id);
+ return -ENODEV;
+ }
+ if (!usb_dev->bus) {
+ pr_debug ("usb %s: bus removed?\n", dev->bus_id);
+ return -ENODEV;
+ }
+
+#ifdef CONFIG_USB_DEVICEFS
+ /* If this is available, userspace programs can directly read
+ * all the device descriptors we don't tell them about. Or
+ * even act as usermode drivers.
+ *
+ * FIXME reduce hardwired intelligence here
+ */
+ if (add_uevent_var(envp, num_envp, &i,
+ buffer, buffer_size, &length,
+ "DEVICE=/proc/bus/usb/%03d/%03d",
+ usb_dev->bus->busnum, usb_dev->devnum))
+ return -ENOMEM;
+#endif
+
+ /* per-device configurations are common */
+ if (add_uevent_var(envp, num_envp, &i,
+ buffer, buffer_size, &length,
+ "PRODUCT=%x/%x/%x",
+ le16_to_cpu(usb_dev->descriptor.idVendor),
+ le16_to_cpu(usb_dev->descriptor.idProduct),
+ le16_to_cpu(usb_dev->descriptor.bcdDevice)))
+ return -ENOMEM;
+
+ /* class-based driver binding models */
+ if (add_uevent_var(envp, num_envp, &i,
+ buffer, buffer_size, &length,
+ "TYPE=%d/%d/%d",
+ usb_dev->descriptor.bDeviceClass,
+ usb_dev->descriptor.bDeviceSubClass,
+ usb_dev->descriptor.bDeviceProtocol))
+ return -ENOMEM;
+
+ if (add_uevent_var(envp, num_envp, &i,
+ buffer, buffer_size, &length,
+ "INTERFACE=%d/%d/%d",
+ alt->desc.bInterfaceClass,
+ alt->desc.bInterfaceSubClass,
+ alt->desc.bInterfaceProtocol))
+ return -ENOMEM;
+
+ if (add_uevent_var(envp, num_envp, &i,
+ buffer, buffer_size, &length,
+ "MODALIAS=usb:v%04Xp%04Xd%04Xdc%02Xdsc%02Xdp%02Xic%02Xisc%02Xip%02X",
+ le16_to_cpu(usb_dev->descriptor.idVendor),
+ le16_to_cpu(usb_dev->descriptor.idProduct),
+ le16_to_cpu(usb_dev->descriptor.bcdDevice),
+ usb_dev->descriptor.bDeviceClass,
+ usb_dev->descriptor.bDeviceSubClass,
+ usb_dev->descriptor.bDeviceProtocol,
+ alt->desc.bInterfaceClass,
+ alt->desc.bInterfaceSubClass,
+ alt->desc.bInterfaceProtocol))
+ return -ENOMEM;
+
+ envp[i] = NULL;
+
+ return 0;
+}
+
+#else
+
+static int usb_uevent(struct device *dev, char **envp,
+ int num_envp, char *buffer, int buffer_size)
+{
+ return -ENODEV;
+}
+
+#endif /* CONFIG_HOTPLUG */
+