drivers/usb/core/usb-acpi.c

   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
  22 /**
  23  * usb_acpi_power_manageable - check whether usb port has
  24  * acpi power resource.
  25  * @hdev: USB device belonging to the usb hub
  26  * @index: port index based zero
  27  *
  28  * Return true if the port has acpi power resource and false if no.
  29  */
  30 bool usb_acpi_power_manageable(struct usb_device *hdev, int index)
  31 {
  32         acpi_handle port_handle;
  33         int port1 = index + 1;
  34
  35         port_handle = usb_get_hub_port_acpi_handle(hdev,
  36                 port1);
  37         if (port_handle)
  38                 return acpi_bus_power_manageable(port_handle);
  39         else
  40                 return false;
  41 }
  42 EXPORT_SYMBOL_GPL(usb_acpi_power_manageable);
  43
  44 /**
  45  * usb_acpi_set_power_state - control usb port's power via acpi power
  46  * resource
  47  * @hdev: USB device belonging to the usb hub
  48  * @index: port index based zero
  49  * @enable: power state expected to be set
  50  *
  51  * Notice to use usb_acpi_power_manageable() to check whether the usb port
  52  * has acpi power resource before invoking this function.
  53  *
  54  * Returns 0 on success, else negative errno.
  55  */
  56 int usb_acpi_set_power_state(struct usb_device *hdev, int index, bool enable)
  57 {
  58         acpi_handle port_handle;
  59         unsigned char state;
  60         int port1 = index + 1;
  61         int error = -EINVAL;
  62
  63         port_handle = (acpi_handle)usb_get_hub_port_acpi_handle(hdev,
  64                 port1);
  65         if (!port_handle)
  66                 return error;
  67
  68         if (enable)
  69                 state = ACPI_STATE_D0;
  70         else
  71                 state = ACPI_STATE_D3_COLD;
  72
  73         error = acpi_bus_set_power(port_handle, state);
  74         if (!error)
  75                 dev_dbg(&hdev->dev, "The power of hub port %d was set to %d\n",
  76                         port1, enable);
  77         else
  78                 dev_dbg(&hdev->dev, "The power of hub port failed to be set\n");
  79
  80         return error;
  81 }
  82 EXPORT_SYMBOL_GPL(usb_acpi_set_power_state);
  83
  84 static int usb_acpi_check_port_connect_type(struct usb_device *hdev,
  85         acpi_handle handle, int port1)
  86 {
  87         acpi_status status;
  88         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
  89         union acpi_object *upc;
  90         struct acpi_pld pld;
  91         int ret = 0;
  92
  93         /*
  94          * Accoding to ACPI Spec 9.13. PLD indicates whether usb port is
  95          * user visible and _UPC indicates whether it is connectable. If
  96          * the port was visible and connectable, it could be freely connected
  97          * and disconnected with USB devices. If no visible and connectable,
  98          * a usb device is directly hard-wired to the port. If no visible and
  99          * no connectable, the port would be not used.
 100          */
 101         status = acpi_get_physical_device_location(handle, &pld);
 102         if (ACPI_FAILURE(status))
 103                 return -ENODEV;
 104
 105         status = acpi_evaluate_object(handle, "_UPC", NULL, &buffer);
 106         upc = buffer.pointer;
 107         if (!upc || (upc->type != ACPI_TYPE_PACKAGE)
 108                 || upc->package.count != 4) {
 109                 ret = -EINVAL;
 110                 goto out;
 111         }
 112
 113         if (upc->package.elements[0].integer.value)
 114                 if (pld.user_visible)
 115                         usb_set_hub_port_connect_type(hdev, port1,
 116                                 USB_PORT_CONNECT_TYPE_HOT_PLUG);
 117                 else
 118                         usb_set_hub_port_connect_type(hdev, port1,
 119                                 USB_PORT_CONNECT_TYPE_HARD_WIRED);
 120         else if (!pld.user_visible)
 121                 usb_set_hub_port_connect_type(hdev, port1, USB_PORT_NOT_USED);
 122
 123 out:
 124         kfree(upc);
 125         return ret;
 126 }
 127
 128 static int usb_acpi_find_device(struct device *dev, acpi_handle *handle)
 129 {
 130         struct usb_device *udev;
 131         acpi_handle *parent_handle;
 132         int port_num;
 133
 134         /*
 135          * In the ACPI DSDT table, only usb root hub and usb ports are
 136          * acpi device nodes. The hierarchy like following.
 137          * Device (EHC1)
 138          *      Device (HUBN)
 139          *              Device (PR01)
 140          *                      Device (PR11)
 141          *                      Device (PR12)
 142          *                      Device (PR13)
 143          *                      ...
 144          * So all binding process is divided into two parts. binding
 145          * root hub and usb ports.
 146          */
 147         if (is_usb_device(dev)) {
 148                 udev = to_usb_device(dev);
 149                 if (udev->parent) {
 150                         enum usb_port_connect_type type;
 151
 152                         /*
 153                          * According usb port's connect type to set usb device's
 154                          * removability.
 155                          */
 156                         type = usb_get_hub_port_connect_type(udev->parent,
 157                                 udev->portnum);
 158                         switch (type) {
 159                         case USB_PORT_CONNECT_TYPE_HOT_PLUG:
 160                                 udev->removable = USB_DEVICE_REMOVABLE;
 161                                 break;
 162                         case USB_PORT_CONNECT_TYPE_HARD_WIRED:
 163                                 udev->removable = USB_DEVICE_FIXED;
 164                                 break;
 165                         default:
 166                                 udev->removable = USB_DEVICE_REMOVABLE_UNKNOWN;
 167                                 break;
 168                         }
 169
 170                         return -ENODEV;
 171                 }
 172
 173                 /* root hub's parent is the usb hcd. */
 174                 parent_handle = DEVICE_ACPI_HANDLE(dev->parent);
 175                 *handle = acpi_get_child(parent_handle, udev->portnum);
 176                 if (!*handle)
 177                         return -ENODEV;
 178                 return 0;
 179         } else if (is_usb_port(dev)) {
 180                 sscanf(dev_name(dev), "port%d", &port_num);
 181                 /* Get the struct usb_device point of port's hub */
 182                 udev = to_usb_device(dev->parent->parent);
 183
 184                 /*
 185                  * The root hub ports' parent is the root hub. The non-root-hub
 186                  * ports' parent is the parent hub port which the hub is
 187                  * connected to.
 188                  */
 189                 if (!udev->parent) {
 190                         *handle = acpi_get_child(DEVICE_ACPI_HANDLE(&udev->dev),
 191                                 port_num);
 192                         if (!*handle)
 193                                 return -ENODEV;
 194                 } else {
 195                         parent_handle =
 196                                 usb_get_hub_port_acpi_handle(udev->parent,
 197                                 udev->portnum);
 198                         if (!parent_handle)
 199                                 return -ENODEV;
 200
 201                         *handle = acpi_get_child(parent_handle, port_num);
 202                         if (!*handle)
 203                                 return -ENODEV;
 204                 }
 205                 usb_acpi_check_port_connect_type(udev, *handle, port_num);
 206         } else
 207                 return -ENODEV;
 208
 209         return 0;
 210 }
 211
 212 static struct acpi_bus_type usb_acpi_bus = {
 213         .bus = &usb_bus_type,
 214         .find_bridge = usb_acpi_find_device,
 215         .find_device = usb_acpi_find_device,
 216 };
 217
 218 int usb_acpi_register(void)
 219 {
 220         return register_acpi_bus_type(&usb_acpi_bus);
 221 }
 222
 223 void usb_acpi_unregister(void)
 224 {
 225         unregister_acpi_bus_type(&usb_acpi_bus);
 226 }