usb-acpi.c

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/*
 * USB-ACPI glue code
 *
 * Copyright 2012 Red Hat <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation, version 2.
 *
 */
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/acpi.h>
#include <linux/pci.h>
#include <acpi/acpi_bus.h>

#include "usb.h"

bool usb_acpi_power_manageable(struct usb_device *hdev, int index)
{
    acpi_handle port_handle;
    int port1 = index + 1;

    port_handle = usb_get_hub_port_acpi_handle(hdev,
        port1);
    if (port_handle)
        return acpi_bus_power_manageable(port_handle);
    else
        return false;
}
EXPORT_SYMBOL_GPL(usb_acpi_power_manageable);

int usb_acpi_set_power_state(struct usb_device *hdev, int index, bool enable)
{
    acpi_handle port_handle;
    unsigned char state;
    int port1 = index + 1;
    int error = -EINVAL;

    port_handle = (acpi_handle)usb_get_hub_port_acpi_handle(hdev,
        port1);
    if (!port_handle)
        return error;

    if (enable)
        state = ACPI_STATE_D0;
    else
        state = ACPI_STATE_D3_COLD;

    error = acpi_bus_set_power(port_handle, state);
    if (!error)
        dev_dbg(&hdev->dev, "The power of hub port %d was set to %d\n",
            port1, enable);
    else
        dev_dbg(&hdev->dev, "The power of hub port failed to be set\n");

    return error;
}
EXPORT_SYMBOL_GPL(usb_acpi_set_power_state);

static int usb_acpi_check_port_connect_type(struct usb_device *hdev,
    acpi_handle handle, int port1)
{
    acpi_status status;
    struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
    union acpi_object *upc;
    struct acpi_pld_info *pld;
    int ret = 0;

    /*
     * Accoding to ACPI Spec 9.13. PLD indicates whether usb port is
     * user visible and _UPC indicates whether it is connectable. If
     * the port was visible and connectable, it could be freely connected
     * and disconnected with USB devices. If no visible and connectable,
     * a usb device is directly hard-wired to the port. If no visible and
     * no connectable, the port would be not used.
     */
    status = acpi_get_physical_device_location(handle, &pld);
    if (ACPI_FAILURE(status))
        return -ENODEV;

    status = acpi_evaluate_object(handle, "_UPC", NULL, &buffer);
    upc = buffer.pointer;
    if (!upc || (upc->type != ACPI_TYPE_PACKAGE)
        || upc->package.count != 4) {
        ret = -EINVAL;
        goto out;
    }

    if (upc->package.elements[0].integer.value)
        if (pld->user_visible)
            usb_set_hub_port_connect_type(hdev, port1,
                USB_PORT_CONNECT_TYPE_HOT_PLUG);
        else
            usb_set_hub_port_connect_type(hdev, port1,
                USB_PORT_CONNECT_TYPE_HARD_WIRED);
    else if (!pld->user_visible)
        usb_set_hub_port_connect_type(hdev, port1, USB_PORT_NOT_USED);

out:
    ACPI_FREE(pld);
    kfree(upc);
    return ret;
}

static int usb_acpi_find_device(struct device *dev, acpi_handle *handle)
{
    struct usb_device *udev;
    acpi_handle *parent_handle;
    int port_num;

    /*
     * In the ACPI DSDT table, only usb root hub and usb ports are
     * acpi device nodes. The hierarchy like following.
     * Device (EHC1)
     *  Device (HUBN)
     *      Device (PR01)
     *          Device (PR11)
     *          Device (PR12)
     *          Device (PR13)
     *          ...
     * So all binding process is divided into two parts. binding
     * root hub and usb ports.
     */
    if (is_usb_device(dev)) {
        udev = to_usb_device(dev);
        if (udev->parent) {
            enum usb_port_connect_type type;

            /*
             * According usb port's connect type to set usb device's
             * removability.
             */
            type = usb_get_hub_port_connect_type(udev->parent,
                udev->portnum);
            switch (type) {
            case USB_PORT_CONNECT_TYPE_HOT_PLUG:
                udev->removable = USB_DEVICE_REMOVABLE;
                break;
            case USB_PORT_CONNECT_TYPE_HARD_WIRED:
                udev->removable = USB_DEVICE_FIXED;
                break;
            default:
                udev->removable = USB_DEVICE_REMOVABLE_UNKNOWN;
                break;
            }

            return -ENODEV;
        }

        /* root hub's parent is the usb hcd. */
        parent_handle = DEVICE_ACPI_HANDLE(dev->parent);
        *handle = acpi_get_child(parent_handle, udev->portnum);
        if (!*handle)
            return -ENODEV;
        return 0;
    } else if (is_usb_port(dev)) {
        sscanf(dev_name(dev), "port%d", &port_num);
        /* Get the struct usb_device point of port's hub */
        udev = to_usb_device(dev->parent->parent);

        /*
         * The root hub ports' parent is the root hub. The non-root-hub
         * ports' parent is the parent hub port which the hub is
         * connected to.
         */
        if (!udev->parent) {
            *handle = acpi_get_child(DEVICE_ACPI_HANDLE(&udev->dev),
                port_num);
            if (!*handle)
                return -ENODEV;
        } else {
            parent_handle =
                usb_get_hub_port_acpi_handle(udev->parent,
                udev->portnum);
            if (!parent_handle)
                return -ENODEV;

            *handle = acpi_get_child(parent_handle, port_num);
            if (!*handle)
                return -ENODEV;
        }
        usb_acpi_check_port_connect_type(udev, *handle, port_num);
    } else
        return -ENODEV;

    return 0;
}

static struct acpi_bus_type usb_acpi_bus = {
    .bus = &usb_bus_type,
    .find_bridge = usb_acpi_find_device,
    .find_device = usb_acpi_find_device,
};

int usb_acpi_register(void)
{
    return register_acpi_bus_type(&usb_acpi_bus);
}

void usb_acpi_unregister(void)
{
    unregister_acpi_bus_type(&usb_acpi_bus);
}