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 <linux/usb/hcd.h>
  19
  20 #include "hub.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         struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
  59         struct usb_port *port_dev;
  60         acpi_handle port_handle;
  61         unsigned char state;
  62         int port1 = index + 1;
  63         int error = -EINVAL;
  64
  65         if (!hub)
  66                 return -ENODEV;
  67         port_dev = hub->ports[port1 - 1];
  68
  69         port_handle = (acpi_handle) usb_get_hub_port_acpi_handle(hdev, port1);
  70         if (!port_handle)
  71                 return error;
  72
  73         if (enable)
  74                 state = ACPI_STATE_D0;
  75         else
  76                 state = ACPI_STATE_D3_COLD;
  77
  78         error = acpi_bus_set_power(port_handle, state);
  79         if (!error)
  80                 dev_dbg(&port_dev->dev, "acpi: power was set to %d\n", enable);
  81         else
  82                 dev_dbg(&port_dev->dev, "acpi: power failed to be set\n");
  83
  84         return error;
  85 }
  86 EXPORT_SYMBOL_GPL(usb_acpi_set_power_state);
  87
  88 static enum usb_port_connect_type usb_acpi_get_connect_type(acpi_handle handle,
  89                 struct acpi_pld_info *pld)
  90 {
  91         enum usb_port_connect_type connect_type = USB_PORT_CONNECT_TYPE_UNKNOWN;
  92         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
  93         union acpi_object *upc;
  94         acpi_status status;
  95
  96         /*
  97          * According to ACPI Spec 9.13. PLD indicates whether usb port is
  98          * user visible and _UPC indicates whether it is connectable. If
  99          * the port was visible and connectable, it could be freely connected
 100          * and disconnected with USB devices. If no visible and connectable,
 101          * a usb device is directly hard-wired to the port. If no visible and
 102          * no connectable, the port would be not used.
 103          */
 104         status = acpi_evaluate_object(handle, "_UPC", NULL, &buffer);
 105         upc = buffer.pointer;
 106         if (!upc || (upc->type != ACPI_TYPE_PACKAGE)
 107                 || upc->package.count != 4) {
 108                 goto out;
 109         }
 110
 111         if (upc->package.elements[0].integer.value)
 112                 if (pld->user_visible)
 113                         connect_type = USB_PORT_CONNECT_TYPE_HOT_PLUG;
 114                 else
 115                         connect_type = USB_PORT_CONNECT_TYPE_HARD_WIRED;
 116         else if (!pld->user_visible)
 117                 connect_type = USB_PORT_NOT_USED;
 118 out:
 119         kfree(upc);
 120         return connect_type;
 121 }
 122
 123
 124 /*
 125  * Private to usb-acpi, all the core needs to know is that
 126  * port_dev->location is non-zero when it has been set by the firmware.
 127  */
 128 #define USB_ACPI_LOCATION_VALID (1 << 31)
 129
 130 static struct acpi_device *usb_acpi_find_companion(struct device *dev)
 131 {
 132         struct usb_device *udev;
 133         struct acpi_device *adev;
 134         acpi_handle *parent_handle;
 135
 136         /*
 137          * In the ACPI DSDT table, only usb root hub and usb ports are
 138          * acpi device nodes. The hierarchy like following.
 139          * Device (EHC1)
 140          *      Device (HUBN)
 141          *              Device (PR01)
 142          *                      Device (PR11)
 143          *                      Device (PR12)
 144          *                      Device (PR13)
 145          *                      ...
 146          * So all binding process is divided into two parts. binding
 147          * root hub and usb ports.
 148          */
 149         if (is_usb_device(dev)) {
 150                 udev = to_usb_device(dev);
 151                 if (udev->parent)
 152                         return NULL;
 153
 154                 /* root hub is only child (_ADR=0) under its parent, the HC */
 155                 adev = ACPI_COMPANION(dev->parent);
 156                 return acpi_find_child_device(adev, 0, false);
 157         } else if (is_usb_port(dev)) {
 158                 struct usb_port *port_dev = to_usb_port(dev);
 159                 int port1 = port_dev->portnum;
 160                 struct acpi_pld_info *pld;
 161                 acpi_handle *handle;
 162                 acpi_status status;
 163
 164                 /* Get the struct usb_device point of port's hub */
 165                 udev = to_usb_device(dev->parent->parent);
 166
 167                 /*
 168                  * The root hub ports' parent is the root hub. The non-root-hub
 169                  * ports' parent is the parent hub port which the hub is
 170                  * connected to.
 171                  */
 172                 if (!udev->parent) {
 173                         struct usb_hcd *hcd = bus_to_hcd(udev->bus);
 174                         int raw;
 175
 176                         raw = usb_hcd_find_raw_port_number(hcd, port1);
 177                         adev = acpi_find_child_device(ACPI_COMPANION(&udev->dev),
 178                                         raw, false);
 179                         if (!adev)
 180                                 return NULL;
 181                 } else {
 182                         parent_handle =
 183                                 usb_get_hub_port_acpi_handle(udev->parent,
 184                                 udev->portnum);
 185                         if (!parent_handle)
 186                                 return NULL;
 187
 188                         acpi_bus_get_device(parent_handle, &adev);
 189                         adev = acpi_find_child_device(adev, port1, false);
 190                         if (!adev)
 191                                 return NULL;
 192                 }
 193                 handle = adev->handle;
 194                 status = acpi_get_physical_device_location(handle, &pld);
 195                 if (ACPI_FAILURE(status) || !pld)
 196                         return adev;
 197
 198                 port_dev->location = USB_ACPI_LOCATION_VALID
 199                         | pld->group_token << 8 | pld->group_position;
 200                 port_dev->connect_type = usb_acpi_get_connect_type(handle, pld);
 201                 ACPI_FREE(pld);
 202
 203                 return adev;
 204         }
 205
 206         return NULL;
 207 }
 208
 209 static bool usb_acpi_bus_match(struct device *dev)
 210 {
 211         return is_usb_device(dev) || is_usb_port(dev);
 212 }
 213
 214 static struct acpi_bus_type usb_acpi_bus = {
 215         .name = "USB",
 216         .match = usb_acpi_bus_match,
 217         .find_companion = usb_acpi_find_companion,
 218 };
 219
 220 int usb_acpi_register(void)
 221 {
 222         return register_acpi_bus_type(&usb_acpi_bus);
 223 }
 224
 225 void usb_acpi_unregister(void)
 226 {
 227         unregister_acpi_bus_type(&usb_acpi_bus);
 228 }