1/*
  2 * USB-ACPI glue code
  3 *
  4 * Copyright 2012 Red Hat <mjg@redhat.com>
  5 *
  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.
  9 *
 10 */
 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>
 19
 20#include "usb.h"
 21
 22static int usb_acpi_check_upc(struct usb_device *udev, acpi_handle handle)
 23{
 24	acpi_status status;
 25	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 26	union acpi_object *upc;
 27	int ret = 0;
 28
 29	status = acpi_evaluate_object(handle, "_UPC", NULL, &buffer);
 30
 31	if (ACPI_FAILURE(status))
 32		return -ENODEV;
 33
 34	upc = buffer.pointer;
 35
 36	if (!upc || (upc->type != ACPI_TYPE_PACKAGE)
 37		|| upc->package.count != 4) {
 38		ret = -EINVAL;
 39		goto out;
 40	}
 41
 42	if (upc->package.elements[0].integer.value)
 43		udev->removable = USB_DEVICE_REMOVABLE;
 44	else
 45		udev->removable = USB_DEVICE_FIXED;
 46
 47out:
 48	kfree(upc);
 49	return ret;
 50}
 51
 52static int usb_acpi_check_pld(struct usb_device *udev, acpi_handle handle)
 53{
 54	acpi_status status;
 55	struct acpi_pld pld;
 56
 57	status = acpi_get_physical_device_location(handle, &pld);
 58
 59	if (ACPI_FAILURE(status))
 60		return -ENODEV;
 61
 62	if (pld.user_visible)
 63		udev->removable = USB_DEVICE_REMOVABLE;
 64	else
 65		udev->removable = USB_DEVICE_FIXED;
 66
 67	return 0;
 68}
 69
 70static int usb_acpi_find_device(struct device *dev, acpi_handle *handle)
 71{
 72	struct usb_device *udev;
 73	struct device *parent;
 74	acpi_handle *parent_handle;
 75
 76	if (!is_usb_device(dev))
 77		return -ENODEV;
 78
 79	udev = to_usb_device(dev);
 80	parent = dev->parent;
 81	parent_handle = DEVICE_ACPI_HANDLE(parent);
 82
 83	if (!parent_handle)
 84		return -ENODEV;
 85
 86	*handle = acpi_get_child(parent_handle, udev->portnum);
 87
 88	if (!*handle)
 89		return -ENODEV;
 90
 91	/*
 92	 * PLD will tell us whether a port is removable to the user or
 93	 * not. If we don't get an answer from PLD (it's not present
 94	 * or it's malformed) then try to infer it from UPC. If a
 95	 * device isn't connectable then it's probably not removable.
 96	 */
 97	if (usb_acpi_check_pld(udev, *handle) != 0)
 98		usb_acpi_check_upc(udev, *handle);
 99
100	return 0;
101}
102
103static struct acpi_bus_type usb_acpi_bus = {
104	.bus = &usb_bus_type,
105	.find_bridge = NULL,
106	.find_device = usb_acpi_find_device,
107};
108
109int usb_acpi_register(void)
110{
111	return register_acpi_bus_type(&usb_acpi_bus);
112}
113
114void usb_acpi_unregister(void)
115{
116	unregister_acpi_bus_type(&usb_acpi_bus);
117}