// SPDX-License-Identifier: GPL-2.0
/*
 * drivers/usb/generic.c - generic driver for USB devices (not interfaces)
 *
 * (C) Copyright 2005 Greg Kroah-Hartman <gregkh@suse.de>
 *
 * based on drivers/usb/usb.c which had the following copyrights:
 *      (C) Copyright Linus Torvalds 1999
 *      (C) Copyright Johannes Erdfelt 1999-2001
 *      (C) Copyright Andreas Gal 1999
 *      (C) Copyright Gregory P. Smith 1999
 *      (C) Copyright Deti Fliegl 1999 (new USB architecture)
 *      (C) Copyright Randy Dunlap 2000
 *      (C) Copyright David Brownell 2000-2004
 *      (C) Copyright Yggdrasil Computing, Inc. 2000
 *              (usb_device_id matching changes by Adam J. Richter)
 *      (C) Copyright Greg Kroah-Hartman 2002-2003
 *
 * Released under the GPLv2 only.
 */

#include <linux/usb.h>
#include <linux/usb/hcd.h>
#include <uapi/linux/usb/audio.h>
#include "usb.h"

static inline const char *plural(int n)
{
        return (n == 1 ? "" : "s");
}

static int is_rndis(struct usb_interface_descriptor *desc)
{
        return desc->bInterfaceClass == USB_CLASS_COMM
                && desc->bInterfaceSubClass == 2
                && desc->bInterfaceProtocol == 0xff;
}

static int is_activesync(struct usb_interface_descriptor *desc)
{
        return desc->bInterfaceClass == USB_CLASS_MISC
                && desc->bInterfaceSubClass == 1
                && desc->bInterfaceProtocol == 1;
}

static bool is_audio(struct usb_interface_descriptor *desc)
{
        return desc->bInterfaceClass == USB_CLASS_AUDIO;
}

static bool is_uac3_config(struct usb_interface_descriptor *desc)
{
        return desc->bInterfaceProtocol == UAC_VERSION_3;
}

int usb_choose_configuration(struct usb_device *udev)
{
        int i;
        int num_configs;
        int insufficient_power = 0;
        struct usb_host_config *c, *best;

        if (usb_device_is_owned(udev))
                return 0;

        best = NULL;
        c = udev->config;
        num_configs = udev->descriptor.bNumConfigurations;
        for (i = 0; i < num_configs; (i++, c++)) {
                struct usb_interface_descriptor *desc = NULL;

                /* It's possible that a config has no interfaces! */
                if (c->desc.bNumInterfaces > 0)
                        desc = &c->intf_cache[0]->altsetting->desc;

                /*
                 * HP's USB bus-powered keyboard has only one configuration
                 * and it claims to be self-powered; other devices may have
                 * similar errors in their descriptors.  If the next test
                 * were allowed to execute, such configurations would always
                 * be rejected and the devices would not work as expected.
                 * In the meantime, we run the risk of selecting a config
                 * that requires external power at a time when that power
                 * isn't available.  It seems to be the lesser of two evils.
                 *
                 * Bugzilla #6448 reports a device that appears to crash
                 * when it receives a GET_DEVICE_STATUS request!  We don't
                 * have any other way to tell whether a device is self-powered,
                 * but since we don't use that information anywhere but here,
                 * the call has been removed.
                 *
                 * Maybe the GET_DEVICE_STATUS call and the test below can
                 * be reinstated when device firmwares become more reliable.
                 * Don't hold your breath.
                 */
#if 0
                /* Rule out self-powered configs for a bus-powered device */
                if (bus_powered && (c->desc.bmAttributes &
                                        USB_CONFIG_ATT_SELFPOWER))
                        continue;
#endif

                /*
                 * The next test may not be as effective as it should be.
                 * Some hubs have errors in their descriptor, claiming
                 * to be self-powered when they are really bus-powered.
                 * We will overestimate the amount of current such hubs
                 * make available for each port.
                 *
                 * This is a fairly benign sort of failure.  It won't
                 * cause us to reject configurations that we should have
                 * accepted.
                 */

                /* Rule out configs that draw too much bus current */
                if (usb_get_max_power(udev, c) > udev->bus_mA) {
                        insufficient_power++;
                        continue;
                }

                /*
                 * Select first configuration as default for audio so that
                 * devices that don't comply with UAC3 protocol are supported.
                 * But, still iterate through other configurations and
                 * select UAC3 compliant config if present.
                 */
                if (desc && is_audio(desc)) {
                        /* Always prefer the first found UAC3 config */
                        if (is_uac3_config(desc)) {
                                best = c;
                                break;
                        }

                        /* If there is no UAC3 config, prefer the first config */
                        else if (i == 0)
                                best = c;

                        /* Unconditional continue, because the rest of the code
                         * in the loop is irrelevant for audio devices, and
                         * because it can reassign best, which for audio devices
                         * we don't want.
                         */
                        continue;
                }

                /* When the first config's first interface is one of Microsoft's
                 * pet nonstandard Ethernet-over-USB protocols, ignore it unless
                 * this kernel has enabled the necessary host side driver.
                 * But: Don't ignore it if it's the only config.
                 */
                if (i == 0 && num_configs > 1 && desc &&
                                (is_rndis(desc) || is_activesync(desc))) {
#if !defined(CONFIG_USB_NET_RNDIS_HOST) && !defined(CONFIG_USB_NET_RNDIS_HOST_MODULE)
                        continue;
#else
                        best = c;
#endif
                }

                /* From the remaining configs, choose the first one whose
                 * first interface is for a non-vendor-specific class.
                 * Reason: Linux is more likely to have a class driver
                 * than a vendor-specific driver. */
                else if (udev->descriptor.bDeviceClass !=
                                                USB_CLASS_VENDOR_SPEC &&
                                (desc && desc->bInterfaceClass !=
                                                USB_CLASS_VENDOR_SPEC)) {
                        best = c;
                        break;
                }

                /* If all the remaining configs are vendor-specific,
                 * choose the first one. */
                else if (!best)
                        best = c;
        }

        if (insufficient_power > 0)
                dev_info(&udev->dev, "rejected %d configuration%s "
                        "due to insufficient available bus power\n",
                        insufficient_power, plural(insufficient_power));

        if (best) {
                i = best->desc.bConfigurationValue;
                dev_dbg(&udev->dev,
                        "configuration #%d chosen from %d choice%s\n",
                        i, num_configs, plural(num_configs));
        } else {
                i = -1;
                dev_warn(&udev->dev,
                        "no configuration chosen from %d choice%s\n",
                        num_configs, plural(num_configs));
        }
        return i;
}
EXPORT_SYMBOL_GPL(usb_choose_configuration);

static int __check_for_non_generic_match(struct device_driver *drv, void *data)
{
        struct usb_device *udev = data;
        struct usb_device_driver *udrv;

        if (!is_usb_device_driver(drv))
                return 0;
        udrv = to_usb_device_driver(drv);
        if (udrv == &usb_generic_driver)
                return 0;
        return usb_driver_applicable(udev, udrv);
}

static bool usb_generic_driver_match(struct usb_device *udev)
{
        if (udev->use_generic_driver)
                return true;

        /*
         * If any other driver wants the device, leave the device to this other
         * driver.
         */
        if (bus_for_each_drv(&usb_bus_type, NULL, udev, __check_for_non_generic_match))
                return false;

        return true;
}

int usb_generic_driver_probe(struct usb_device *udev)
{
        int err, c;

        /* Choose and set the configuration.  This registers the interfaces
         * with the driver core and lets interface drivers bind to them.
         */
        if (udev->authorized == 0)
                dev_err(&udev->dev, "Device is not authorized for usage\n");
        else {
                c = usb_choose_configuration(udev);
                if (c >= 0) {
                        err = usb_set_configuration(udev, c);
                        if (err && err != -ENODEV) {
                                dev_err(&udev->dev, "can't set config #%d, error %d\n",
                                        c, err);
                                /* This need not be fatal.  The user can try to
                                 * set other configurations. */
                        }
                }
        }
        /* USB device state == configured ... usable */
        usb_notify_add_device(udev);

        return 0;
}

void usb_generic_driver_disconnect(struct usb_device *udev)
{
        usb_notify_remove_device(udev);

        /* if this is only an unbind, not a physical disconnect, then
         * unconfigure the device */
        if (udev->actconfig)
                usb_set_configuration(udev, -1);
}

#ifdef  CONFIG_PM

int usb_generic_driver_suspend(struct usb_device *udev, pm_message_t msg)
{
        int rc;

        /* Normal USB devices suspend through their upstream port.
         * Root hubs don't have upstream ports to suspend,
         * so we have to shut down their downstream HC-to-USB
         * interfaces manually by doing a bus (or "global") suspend.
         */
        if (!udev->parent)
                rc = hcd_bus_suspend(udev, msg);

        /*
         * Non-root USB2 devices don't need to do anything for FREEZE
         * or PRETHAW. USB3 devices don't support global suspend and
         * needs to be selectively suspended.
         */
        else if ((msg.event == PM_EVENT_FREEZE || msg.event == PM_EVENT_PRETHAW)
                 && (udev->speed < USB_SPEED_SUPER))
                rc = 0;
        else
                rc = usb_port_suspend(udev, msg);

        if (rc == 0)
                usbfs_notify_suspend(udev);
        return rc;
}

int usb_generic_driver_resume(struct usb_device *udev, pm_message_t msg)
{
        int rc;

        /* Normal USB devices resume/reset through their upstream port.
         * Root hubs don't have upstream ports to resume or reset,
         * so we have to start up their downstream HC-to-USB
         * interfaces manually by doing a bus (or "global") resume.
         */
        if (!udev->parent)
                rc = hcd_bus_resume(udev, msg);
        else
                rc = usb_port_resume(udev, msg);

        if (rc == 0)
                usbfs_notify_resume(udev);
        return rc;
}

#endif  /* CONFIG_PM */

struct usb_device_driver usb_generic_driver = {
        .name = "usb",
        .match = usb_generic_driver_match,
        .probe = usb_generic_driver_probe,
        .disconnect = usb_generic_driver_disconnect,
#ifdef  CONFIG_PM
        .suspend = usb_generic_driver_suspend,
        .resume = usb_generic_driver_resume,
#endif
        .supports_autosuspend = 1,
};