4 * Copyright 2012 Red Hat <mjg@redhat.com>
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the Free
8 * Software Foundation, version 2.
11 #include <linux/module.h>
12 #include <linux/usb.h>
13 #include <linux/device.h>
14 #include <linux/errno.h>
15 #include <linux/kernel.h>
16 #include <linux/acpi.h>
17 #include <linux/pci.h>
18 #include <acpi/acpi_bus.h>
22 static int usb_acpi_check_upc(struct usb_device *udev, acpi_handle handle)
25 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
26 union acpi_object *upc;
29 status = acpi_evaluate_object(handle, "_UPC", NULL, &buffer);
31 if (ACPI_FAILURE(status))
36 if (!upc || (upc->type != ACPI_TYPE_PACKAGE)
37 || upc->package.count != 4) {
42 if (upc->package.elements[0].integer.value)
43 udev->removable = USB_DEVICE_REMOVABLE;
45 udev->removable = USB_DEVICE_FIXED;
52 static int usb_acpi_check_pld(struct usb_device *udev, acpi_handle handle)
57 status = acpi_get_physical_device_location(handle, &pld);
59 if (ACPI_FAILURE(status))
63 udev->removable = USB_DEVICE_REMOVABLE;
65 udev->removable = USB_DEVICE_FIXED;
70 static int usb_acpi_find_device(struct device *dev, acpi_handle *handle)
72 struct usb_device *udev;
73 acpi_handle *parent_handle;
77 * In the ACPI DSDT table, only usb root hub and usb ports are
78 * acpi device nodes. The hierarchy like following.
86 * So all binding process is divided into two parts. binding
87 * root hub and usb ports.
89 if (is_usb_device(dev)) {
90 udev = to_usb_device(dev);
93 /* root hub's parent is the usb hcd. */
94 parent_handle = DEVICE_ACPI_HANDLE(dev->parent);
95 *handle = acpi_get_child(parent_handle, udev->portnum);
99 } else if (is_usb_port(dev)) {
100 sscanf(dev_name(dev), "port%d", &port_num);
101 /* Get the struct usb_device point of port's hub */
102 udev = to_usb_device(dev->parent->parent);
105 * The root hub ports' parent is the root hub. The non-root-hub
106 * ports' parent is the parent hub port which the hub is
110 *handle = acpi_get_child(DEVICE_ACPI_HANDLE(&udev->dev),
116 usb_get_hub_port_acpi_handle(udev->parent,
121 *handle = acpi_get_child(parent_handle, port_num);
129 * PLD will tell us whether a port is removable to the user or
130 * not. If we don't get an answer from PLD (it's not present
131 * or it's malformed) then try to infer it from UPC. If a
132 * device isn't connectable then it's probably not removable.
134 if (usb_acpi_check_pld(udev, *handle) != 0)
135 usb_acpi_check_upc(udev, *handle);
140 static struct acpi_bus_type usb_acpi_bus = {
141 .bus = &usb_bus_type,
142 .find_bridge = usb_acpi_find_device,
143 .find_device = usb_acpi_find_device,
146 int usb_acpi_register(void)
148 return register_acpi_bus_type(&usb_acpi_bus);
151 void usb_acpi_unregister(void)
153 unregister_acpi_bus_type(&usb_acpi_bus);