// SPDX-License-Identifier: GPL-2.0
/*
 * USB-ACPI glue code
 *
 * Copyright 2012 Red Hat <mjg@redhat.com>
 */
#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 <linux/usb/hcd.h>

#include "hub.h"

/**
 * usb_acpi_power_manageable - check whether usb port has
 * acpi power resource.
 * @hdev: USB device belonging to the usb hub
 * @index: port index based zero
 *
 * Return true if the port has acpi power resource and false if no.
 */
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);

/**
 * usb_acpi_set_power_state - control usb port's power via acpi power
 * resource
 * @hdev: USB device belonging to the usb hub
 * @index: port index based zero
 * @enable: power state expected to be set
 *
 * Notice to use usb_acpi_power_manageable() to check whether the usb port
 * has acpi power resource before invoking this function.
 *
 * Returns 0 on success, else negative errno.
 */
int usb_acpi_set_power_state(struct usb_device *hdev, int index, bool enable)
{
        struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
        struct usb_port *port_dev;
        acpi_handle port_handle;
        unsigned char state;
        int port1 = index + 1;
        int error = -EINVAL;

        if (!hub)
                return -ENODEV;
        port_dev = hub->ports[port1 - 1];

        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(&port_dev->dev, "acpi: power was set to %d\n", enable);
        else
                dev_dbg(&port_dev->dev, "acpi: power failed to be set\n");

        return error;
}
EXPORT_SYMBOL_GPL(usb_acpi_set_power_state);

static enum usb_port_connect_type usb_acpi_get_connect_type(acpi_handle handle,
                struct acpi_pld_info *pld)
{
        enum usb_port_connect_type connect_type = USB_PORT_CONNECT_TYPE_UNKNOWN;
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
        union acpi_object *upc = NULL;
        acpi_status status;

        /*
         * According to 9.14 in ACPI Spec 6.2. _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_evaluate_object(handle, "_UPC", NULL, &buffer);
        if (ACPI_FAILURE(status))
                goto out;

        upc = buffer.pointer;
        if (!upc || (upc->type != ACPI_TYPE_PACKAGE) || upc->package.count != 4)
                goto out;

        if (upc->package.elements[0].integer.value)
                if (pld->user_visible)
                        connect_type = USB_PORT_CONNECT_TYPE_HOT_PLUG;
                else
                        connect_type = USB_PORT_CONNECT_TYPE_HARD_WIRED;
        else if (!pld->user_visible)
                connect_type = USB_PORT_NOT_USED;
out:
        kfree(upc);
        return connect_type;
}


/*
 * Private to usb-acpi, all the core needs to know is that
 * port_dev->location is non-zero when it has been set by the firmware.
 */
#define USB_ACPI_LOCATION_VALID (1 << 31)

static struct acpi_device *usb_acpi_find_port(struct acpi_device *parent,
                                              int raw)
{
        struct acpi_device *adev;

        if (!parent)
                return NULL;

        list_for_each_entry(adev, &parent->children, node) {
                if (acpi_device_adr(adev) == raw)
                        return adev;
        }

        return acpi_find_child_device(parent, raw, false);
}

static struct acpi_device *
usb_acpi_get_companion_for_port(struct usb_port *port_dev)
{
        struct usb_device *udev;
        struct acpi_device *adev;
        acpi_handle *parent_handle;
        int port1;

        /* Get the struct usb_device point of port's hub */
        udev = to_usb_device(port_dev->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) {
                adev = ACPI_COMPANION(&udev->dev);
                port1 = usb_hcd_find_raw_port_number(bus_to_hcd(udev->bus),
                                                     port_dev->portnum);
        } else {
                parent_handle = usb_get_hub_port_acpi_handle(udev->parent,
                                                             udev->portnum);
                if (!parent_handle)
                        return NULL;

                acpi_bus_get_device(parent_handle, &adev);
                port1 = port_dev->portnum;
        }

        return usb_acpi_find_port(adev, port1);
}

static struct acpi_device *
usb_acpi_find_companion_for_port(struct usb_port *port_dev)
{
        struct acpi_device *adev;
        struct acpi_pld_info *pld;
        acpi_handle *handle;
        acpi_status status;

        adev = usb_acpi_get_companion_for_port(port_dev);
        if (!adev)
                return NULL;

        handle = adev->handle;
        status = acpi_get_physical_device_location(handle, &pld);
        if (ACPI_SUCCESS(status) && pld) {
                port_dev->location = USB_ACPI_LOCATION_VALID
                        | pld->group_token << 8 | pld->group_position;
                port_dev->connect_type = usb_acpi_get_connect_type(handle, pld);
                ACPI_FREE(pld);
        }

        return adev;
}

static struct acpi_device *
usb_acpi_find_companion_for_device(struct usb_device *udev)
{
        struct acpi_device *adev;
        struct usb_port *port_dev;
        struct usb_hub *hub;

        if (!udev->parent) {
                /* root hub is only child (_ADR=0) under its parent, the HC */
                adev = ACPI_COMPANION(udev->dev.parent);
                return acpi_find_child_device(adev, 0, false);
        }

        hub = usb_hub_to_struct_hub(udev->parent);
        if (!hub)
                return NULL;

        /*
         * This is an embedded USB device connected to a port and such
         * devices share port's ACPI companion.
         */
        port_dev = hub->ports[udev->portnum - 1];
        return usb_acpi_get_companion_for_port(port_dev);
}

static struct acpi_device *usb_acpi_find_companion(struct device *dev)
{
        /*
         * The USB hierarchy like following:
         *
         * Device (EHC1)
         *      Device (HUBN)
         *              Device (PR01)
         *                      Device (PR11)
         *                      Device (PR12)
         *                              Device (FN12)
         *                              Device (FN13)
         *                      Device (PR13)
         *                      ...
         * where HUBN is root hub, and PRNN are USB ports and devices
         * connected to them, and FNNN are individualk functions for
         * connected composite USB devices. PRNN and FNNN may contain
         * _CRS and other methods describing sideband resources for
         * the connected device.
         *
         * On the kernel side both root hub and embedded USB devices are
         * represented as instances of usb_device structure, and ports
         * are represented as usb_port structures, so the whole process
         * is split into 2 parts: finding companions for devices and
         * finding companions for ports.
         *
         * Note that we do not handle individual functions of composite
         * devices yet, for that we would need to assign companions to
         * devices corresponding to USB interfaces.
         */
        if (is_usb_device(dev))
                return usb_acpi_find_companion_for_device(to_usb_device(dev));
        else if (is_usb_port(dev))
                return usb_acpi_find_companion_for_port(to_usb_port(dev));

        return NULL;
}

static bool usb_acpi_bus_match(struct device *dev)
{
        return is_usb_device(dev) || is_usb_port(dev);
}

static struct acpi_bus_type usb_acpi_bus = {
        .name = "USB",
        .match = usb_acpi_bus_match,
        .find_companion = usb_acpi_find_companion,
};

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);
}