// SPDX-License-Identifier: GPL-2.0
/*
 * mtu3_gadget.c - MediaTek usb3 DRD peripheral support
 *
 * Copyright (C) 2016 MediaTek Inc.
 *
 * Author: Chunfeng Yun <chunfeng.yun@mediatek.com>
 */

#include <linux/string_choices.h>
#include "mtu3.h"
#include "mtu3_trace.h"

void mtu3_req_complete(struct mtu3_ep *mep,
                     struct usb_request *req, int status)
__releases(mep->mtu->lock)
__acquires(mep->mtu->lock)
{
        struct mtu3_request *mreq = to_mtu3_request(req);
        struct mtu3 *mtu = mreq->mtu;

        list_del(&mreq->list);
        if (req->status == -EINPROGRESS)
                req->status = status;

        trace_mtu3_req_complete(mreq);

        /* ep0 makes use of PIO, needn't unmap it */
        if (mep->epnum)
                usb_gadget_unmap_request(&mtu->g, req, mep->is_in);

        dev_dbg(mtu->dev, "%s complete req: %p, sts %d, %d/%d\n",
                mep->name, req, req->status, req->actual, req->length);

        spin_unlock(&mtu->lock);
        usb_gadget_giveback_request(&mep->ep, req);
        spin_lock(&mtu->lock);
}

static void nuke(struct mtu3_ep *mep, const int status)
{
        struct mtu3_request *mreq = NULL;

        if (list_empty(&mep->req_list))
                return;

        dev_dbg(mep->mtu->dev, "abort %s's req: sts %d\n", mep->name, status);

        /* exclude EP0 */
        if (mep->epnum)
                mtu3_qmu_flush(mep);

        while (!list_empty(&mep->req_list)) {
                mreq = list_first_entry(&mep->req_list,
                                        struct mtu3_request, list);
                mtu3_req_complete(mep, &mreq->request, status);
        }
}

static int mtu3_ep_enable(struct mtu3_ep *mep)
{
        const struct usb_endpoint_descriptor *desc;
        const struct usb_ss_ep_comp_descriptor *comp_desc;
        struct mtu3 *mtu = mep->mtu;
        u32 interval = 0;
        u32 mult = 0;
        u32 burst = 0;
        int ret;

        desc = mep->desc;
        comp_desc = mep->comp_desc;
        mep->type = usb_endpoint_type(desc);
        mep->maxp = usb_endpoint_maxp(desc);

        switch (mtu->g.speed) {
        case USB_SPEED_SUPER:
        case USB_SPEED_SUPER_PLUS:
                if (usb_endpoint_xfer_int(desc) ||
                                usb_endpoint_xfer_isoc(desc)) {
                        interval = desc->bInterval;
                        interval = clamp_val(interval, 1, 16);
                        if (usb_endpoint_xfer_isoc(desc) && comp_desc)
                                mult = comp_desc->bmAttributes;
                }
                if (comp_desc)
                        burst = comp_desc->bMaxBurst;

                break;
        case USB_SPEED_HIGH:
                if (usb_endpoint_xfer_isoc(desc) ||
                                usb_endpoint_xfer_int(desc)) {
                        interval = desc->bInterval;
                        interval = clamp_val(interval, 1, 16);
                        mult = usb_endpoint_maxp_mult(desc) - 1;
                }
                break;
        case USB_SPEED_FULL:
                if (usb_endpoint_xfer_isoc(desc))
                        interval = clamp_val(desc->bInterval, 1, 16);
                else if (usb_endpoint_xfer_int(desc))
                        interval = clamp_val(desc->bInterval, 1, 255);

                break;
        default:
                break; /*others are ignored */
        }

        dev_dbg(mtu->dev, "%s maxp:%d, interval:%d, burst:%d, mult:%d\n",
                __func__, mep->maxp, interval, burst, mult);

        mep->ep.maxpacket = mep->maxp;
        mep->ep.desc = desc;
        mep->ep.comp_desc = comp_desc;

        /* slot mainly affects bulk/isoc transfer, so ignore int */
        mep->slot = usb_endpoint_xfer_int(desc) ? 0 : mtu->slot;

        ret = mtu3_config_ep(mtu, mep, interval, burst, mult);
        if (ret < 0)
                return ret;

        ret = mtu3_gpd_ring_alloc(mep);
        if (ret < 0) {
                mtu3_deconfig_ep(mtu, mep);
                return ret;
        }

        mtu3_qmu_start(mep);

        return 0;
}

static int mtu3_ep_disable(struct mtu3_ep *mep)
{
        struct mtu3 *mtu = mep->mtu;

        /* abort all pending requests */
        nuke(mep, -ESHUTDOWN);
        mtu3_qmu_stop(mep);
        mtu3_deconfig_ep(mtu, mep);
        mtu3_gpd_ring_free(mep);

        mep->desc = NULL;
        mep->ep.desc = NULL;
        mep->comp_desc = NULL;
        mep->type = 0;
        mep->flags = 0;

        return 0;
}

static int mtu3_gadget_ep_enable(struct usb_ep *ep,
                const struct usb_endpoint_descriptor *desc)
{
        struct mtu3_ep *mep;
        struct mtu3 *mtu;
        unsigned long flags;
        int ret = -EINVAL;

        if (!ep || !desc || desc->bDescriptorType != USB_DT_ENDPOINT) {
                pr_debug("%s invalid parameters\n", __func__);
                return -EINVAL;
        }

        if (!desc->wMaxPacketSize) {
                pr_debug("%s missing wMaxPacketSize\n", __func__);
                return -EINVAL;
        }
        mep = to_mtu3_ep(ep);
        mtu = mep->mtu;

        /* check ep number and direction against endpoint */
        if (usb_endpoint_num(desc) != mep->epnum)
                return -EINVAL;

        if (!!usb_endpoint_dir_in(desc) ^ !!mep->is_in)
                return -EINVAL;

        dev_dbg(mtu->dev, "%s %s\n", __func__, ep->name);

        if (mep->flags & MTU3_EP_ENABLED) {
                dev_WARN_ONCE(mtu->dev, true, "%s is already enabled\n",
                                mep->name);
                return 0;
        }

        spin_lock_irqsave(&mtu->lock, flags);
        mep->desc = desc;
        mep->comp_desc = ep->comp_desc;

        ret = mtu3_ep_enable(mep);
        if (ret)
                goto error;

        mep->flags = MTU3_EP_ENABLED;
        mtu->active_ep++;

error:
        spin_unlock_irqrestore(&mtu->lock, flags);

        dev_dbg(mtu->dev, "%s active_ep=%d\n", __func__, mtu->active_ep);
        trace_mtu3_gadget_ep_enable(mep);

        return ret;
}

static int mtu3_gadget_ep_disable(struct usb_ep *ep)
{
        struct mtu3_ep *mep = to_mtu3_ep(ep);
        struct mtu3 *mtu = mep->mtu;
        unsigned long flags;

        dev_dbg(mtu->dev, "%s %s\n", __func__, mep->name);
        trace_mtu3_gadget_ep_disable(mep);

        if (!(mep->flags & MTU3_EP_ENABLED)) {
                dev_warn(mtu->dev, "%s is already disabled\n", mep->name);
                return 0;
        }

        spin_lock_irqsave(&mtu->lock, flags);
        mtu3_ep_disable(mep);
        mep->flags = 0;
        mtu->active_ep--;
        spin_unlock_irqrestore(&(mtu->lock), flags);

        dev_dbg(mtu->dev, "%s active_ep=%d, mtu3 is_active=%d\n",
                __func__, mtu->active_ep, mtu->is_active);

        return 0;
}

struct usb_request *mtu3_alloc_request(struct usb_ep *ep, gfp_t gfp_flags)
{
        struct mtu3_ep *mep = to_mtu3_ep(ep);
        struct mtu3_request *mreq;

        mreq = kzalloc_obj(*mreq, gfp_flags);
        if (!mreq)
                return NULL;

        mreq->request.dma = DMA_ADDR_INVALID;
        mreq->epnum = mep->epnum;
        mreq->mep = mep;
        INIT_LIST_HEAD(&mreq->list);
        trace_mtu3_alloc_request(mreq);

        return &mreq->request;
}

void mtu3_free_request(struct usb_ep *ep, struct usb_request *req)
{
        struct mtu3_request *mreq = to_mtu3_request(req);

        trace_mtu3_free_request(mreq);
        kfree(mreq);
}

static int mtu3_gadget_queue(struct usb_ep *ep,
                struct usb_request *req, gfp_t gfp_flags)
{
        struct mtu3_ep *mep = to_mtu3_ep(ep);
        struct mtu3_request *mreq = to_mtu3_request(req);
        struct mtu3 *mtu = mep->mtu;
        unsigned long flags;
        int ret = 0;

        if (!req->buf)
                return -ENODATA;

        if (mreq->mep != mep)
                return -EINVAL;

        dev_dbg(mtu->dev, "%s %s EP%d(%s), req=%p, maxp=%d, len#%d\n",
                __func__, mep->is_in ? "TX" : "RX", mreq->epnum, ep->name,
                mreq, ep->maxpacket, mreq->request.length);

        if (req->length > GPD_BUF_SIZE ||
            (mtu->gen2cp && req->length > GPD_BUF_SIZE_EL)) {
                dev_warn(mtu->dev,
                        "req length > supported MAX:%d requested:%d\n",
                        mtu->gen2cp ? GPD_BUF_SIZE_EL : GPD_BUF_SIZE,
                        req->length);
                return -EOPNOTSUPP;
        }

        /* don't queue if the ep is down */
        if (!mep->desc) {
                dev_dbg(mtu->dev, "req=%p queued to %s while it's disabled\n",
                        req, ep->name);
                return -ESHUTDOWN;
        }

        mreq->mtu = mtu;
        mreq->request.actual = 0;
        mreq->request.status = -EINPROGRESS;

        ret = usb_gadget_map_request(&mtu->g, req, mep->is_in);
        if (ret) {
                dev_err(mtu->dev, "dma mapping failed\n");
                return ret;
        }

        spin_lock_irqsave(&mtu->lock, flags);

        if (mtu3_prepare_transfer(mep)) {
                ret = -EAGAIN;
                usb_gadget_unmap_request(&mtu->g, req, mep->is_in);
                goto error;
        }

        list_add_tail(&mreq->list, &mep->req_list);
        mtu3_insert_gpd(mep, mreq);
        mtu3_qmu_resume(mep);

error:
        spin_unlock_irqrestore(&mtu->lock, flags);
        trace_mtu3_gadget_queue(mreq);

        return ret;
}

static int mtu3_gadget_dequeue(struct usb_ep *ep, struct usb_request *req)
{
        struct mtu3_ep *mep = to_mtu3_ep(ep);
        struct mtu3_request *mreq = to_mtu3_request(req);
        struct mtu3_request *r;
        struct mtu3 *mtu = mep->mtu;
        unsigned long flags;
        int ret = 0;

        if (mreq->mep != mep)
                return -EINVAL;

        dev_dbg(mtu->dev, "%s : req=%p\n", __func__, req);
        trace_mtu3_gadget_dequeue(mreq);

        spin_lock_irqsave(&mtu->lock, flags);

        list_for_each_entry(r, &mep->req_list, list) {
                if (r == mreq)
                        break;
        }
        if (r != mreq) {
                dev_dbg(mtu->dev, "req=%p not queued to %s\n", req, ep->name);
                ret = -EINVAL;
                goto done;
        }

        mtu3_qmu_flush(mep);  /* REVISIT: set BPS ?? */
        mtu3_req_complete(mep, req, -ECONNRESET);
        mtu3_qmu_start(mep);

done:
        spin_unlock_irqrestore(&mtu->lock, flags);

        return ret;
}

/*
 * Set or clear the halt bit of an EP.
 * A halted EP won't TX/RX any data but will queue requests.
 */
static int mtu3_gadget_ep_set_halt(struct usb_ep *ep, int value)
{
        struct mtu3_ep *mep = to_mtu3_ep(ep);
        struct mtu3 *mtu = mep->mtu;
        struct mtu3_request *mreq;
        unsigned long flags;
        int ret = 0;

        dev_dbg(mtu->dev, "%s : %s...", __func__, ep->name);

        spin_lock_irqsave(&mtu->lock, flags);

        if (mep->type == USB_ENDPOINT_XFER_ISOC) {
                ret = -EINVAL;
                goto done;
        }

        mreq = next_request(mep);
        if (value) {
                /*
                 * If there is not request for TX-EP, QMU will not transfer
                 * data to TX-FIFO, so no need check whether TX-FIFO
                 * holds bytes or not here
                 */
                if (mreq) {
                        dev_dbg(mtu->dev, "req in progress, cannot halt %s\n",
                                ep->name);
                        ret = -EAGAIN;
                        goto done;
                }
        } else {
                mep->flags &= ~MTU3_EP_WEDGE;
        }

        dev_dbg(mtu->dev, "%s %s stall\n", ep->name, value ? "set" : "clear");

        mtu3_ep_stall_set(mep, value);

done:
        spin_unlock_irqrestore(&mtu->lock, flags);
        trace_mtu3_gadget_ep_set_halt(mep);

        return ret;
}

/* Sets the halt feature with the clear requests ignored */
static int mtu3_gadget_ep_set_wedge(struct usb_ep *ep)
{
        struct mtu3_ep *mep = to_mtu3_ep(ep);

        mep->flags |= MTU3_EP_WEDGE;

        return usb_ep_set_halt(ep);
}

static const struct usb_ep_ops mtu3_ep_ops = {
        .enable = mtu3_gadget_ep_enable,
        .disable = mtu3_gadget_ep_disable,
        .alloc_request = mtu3_alloc_request,
        .free_request = mtu3_free_request,
        .queue = mtu3_gadget_queue,
        .dequeue = mtu3_gadget_dequeue,
        .set_halt = mtu3_gadget_ep_set_halt,
        .set_wedge = mtu3_gadget_ep_set_wedge,
};

static int mtu3_gadget_get_frame(struct usb_gadget *gadget)
{
        struct mtu3 *mtu = gadget_to_mtu3(gadget);

        return (int)mtu3_readl(mtu->mac_base, U3D_USB20_FRAME_NUM);
}

static void function_wake_notif(struct mtu3 *mtu, u8 intf)
{
        mtu3_writel(mtu->mac_base, U3D_DEV_NOTIF_0,
                    TYPE_FUNCTION_WAKE | DEV_NOTIF_VAL_FW(intf));
        mtu3_setbits(mtu->mac_base, U3D_DEV_NOTIF_0, SEND_DEV_NOTIF);
}

static int mtu3_gadget_wakeup(struct usb_gadget *gadget)
{
        struct mtu3 *mtu = gadget_to_mtu3(gadget);
        unsigned long flags;

        dev_dbg(mtu->dev, "%s\n", __func__);

        /* remote wakeup feature is not enabled by host */
        if (!mtu->may_wakeup)
                return  -EOPNOTSUPP;

        spin_lock_irqsave(&mtu->lock, flags);
        if (mtu->g.speed >= USB_SPEED_SUPER) {
                /*
                 * class driver may do function wakeup even UFP is in U0,
                 * and UX_EXIT only takes effect in U1/U2/U3;
                 */
                mtu3_setbits(mtu->mac_base, U3D_LINK_POWER_CONTROL, UX_EXIT);
                /*
                 * Assume there's only one function on the composite device
                 * and enable remote wake for the first interface.
                 * FIXME if the IAD (interface association descriptor) shows
                 * there is more than one function.
                 */
                function_wake_notif(mtu, 0);
        } else {
                mtu3_setbits(mtu->mac_base, U3D_POWER_MANAGEMENT, RESUME);
                spin_unlock_irqrestore(&mtu->lock, flags);
                usleep_range(10000, 11000);
                spin_lock_irqsave(&mtu->lock, flags);
                mtu3_clrbits(mtu->mac_base, U3D_POWER_MANAGEMENT, RESUME);
        }
        spin_unlock_irqrestore(&mtu->lock, flags);
        return 0;
}

static int mtu3_gadget_set_self_powered(struct usb_gadget *gadget,
                int is_selfpowered)
{
        struct mtu3 *mtu = gadget_to_mtu3(gadget);

        mtu->is_self_powered = !!is_selfpowered;
        return 0;
}

static int mtu3_gadget_pullup(struct usb_gadget *gadget, int is_on)
{
        struct mtu3 *mtu = gadget_to_mtu3(gadget);
        unsigned long flags;

        dev_dbg(mtu->dev, "%s (%s) for %sactive device\n", __func__,
                str_on_off(is_on), mtu->is_active ? "" : "in");

        pm_runtime_get_sync(mtu->dev);

        /* we'd rather not pullup unless the device is active. */
        spin_lock_irqsave(&mtu->lock, flags);

        is_on = !!is_on;
        if (!mtu->is_active) {
                /* save it for mtu3_start() to process the request */
                mtu->softconnect = is_on;
        } else if (is_on != mtu->softconnect) {
                mtu->softconnect = is_on;
                mtu3_dev_on_off(mtu, is_on);
        }

        spin_unlock_irqrestore(&mtu->lock, flags);
        pm_runtime_put(mtu->dev);

        return 0;
}

static int mtu3_gadget_start(struct usb_gadget *gadget,
                struct usb_gadget_driver *driver)
{
        struct mtu3 *mtu = gadget_to_mtu3(gadget);
        unsigned long flags;

        if (mtu->gadget_driver) {
                dev_err(mtu->dev, "%s is already bound to %s\n",
                        mtu->g.name, mtu->gadget_driver->driver.name);
                return -EBUSY;
        }

        dev_dbg(mtu->dev, "bind driver %s\n", driver->function);
        pm_runtime_get_sync(mtu->dev);

        spin_lock_irqsave(&mtu->lock, flags);

        mtu->softconnect = 0;
        mtu->gadget_driver = driver;

        if (mtu->ssusb->dr_mode == USB_DR_MODE_PERIPHERAL)
                mtu3_start(mtu);

        spin_unlock_irqrestore(&mtu->lock, flags);
        pm_runtime_put(mtu->dev);

        return 0;
}

static void stop_activity(struct mtu3 *mtu)
{
        struct usb_gadget_driver *driver = mtu->gadget_driver;
        int i;

        /* don't disconnect if it's not connected */
        if (mtu->g.speed == USB_SPEED_UNKNOWN)
                driver = NULL;
        else
                mtu->g.speed = USB_SPEED_UNKNOWN;

        /* deactivate the hardware */
        if (mtu->softconnect) {
                mtu->softconnect = 0;
                mtu3_dev_on_off(mtu, 0);
        }

        /*
         * killing any outstanding requests will quiesce the driver;
         * then report disconnect
         */
        nuke(mtu->ep0, -ESHUTDOWN);
        for (i = 1; i < mtu->num_eps; i++) {
                nuke(mtu->in_eps + i, -ESHUTDOWN);
                nuke(mtu->out_eps + i, -ESHUTDOWN);
        }

        if (driver) {
                spin_unlock(&mtu->lock);
                driver->disconnect(&mtu->g);
                spin_lock(&mtu->lock);
        }
}

static int mtu3_gadget_stop(struct usb_gadget *g)
{
        struct mtu3 *mtu = gadget_to_mtu3(g);
        unsigned long flags;

        dev_dbg(mtu->dev, "%s\n", __func__);

        spin_lock_irqsave(&mtu->lock, flags);

        stop_activity(mtu);
        mtu->gadget_driver = NULL;

        if (mtu->ssusb->dr_mode == USB_DR_MODE_PERIPHERAL)
                mtu3_stop(mtu);

        spin_unlock_irqrestore(&mtu->lock, flags);

        synchronize_irq(mtu->irq);
        return 0;
}

static void
mtu3_gadget_set_speed(struct usb_gadget *g, enum usb_device_speed speed)
{
        struct mtu3 *mtu = gadget_to_mtu3(g);
        unsigned long flags;

        dev_dbg(mtu->dev, "%s %s\n", __func__, usb_speed_string(speed));

        spin_lock_irqsave(&mtu->lock, flags);
        mtu->speed = speed;
        spin_unlock_irqrestore(&mtu->lock, flags);
}

static void mtu3_gadget_async_callbacks(struct usb_gadget *g, bool enable)
{
        struct mtu3 *mtu = gadget_to_mtu3(g);
        unsigned long flags;

        dev_dbg(mtu->dev, "%s %s\n", __func__, enable ? "en" : "dis");

        spin_lock_irqsave(&mtu->lock, flags);
        mtu->async_callbacks = enable;
        spin_unlock_irqrestore(&mtu->lock, flags);
}

static const struct usb_gadget_ops mtu3_gadget_ops = {
        .get_frame = mtu3_gadget_get_frame,
        .wakeup = mtu3_gadget_wakeup,
        .set_selfpowered = mtu3_gadget_set_self_powered,
        .pullup = mtu3_gadget_pullup,
        .udc_start = mtu3_gadget_start,
        .udc_stop = mtu3_gadget_stop,
        .udc_set_speed = mtu3_gadget_set_speed,
        .udc_async_callbacks = mtu3_gadget_async_callbacks,
};

static void mtu3_state_reset(struct mtu3 *mtu)
{
        mtu->address = 0;
        mtu->ep0_state = MU3D_EP0_STATE_SETUP;
        mtu->may_wakeup = 0;
        mtu->u1_enable = 0;
        mtu->u2_enable = 0;
        mtu->delayed_status = false;
        mtu->test_mode = false;
}

static void init_hw_ep(struct mtu3 *mtu, struct mtu3_ep *mep,
                u32 epnum, u32 is_in)
{
        mep->epnum = epnum;
        mep->mtu = mtu;
        mep->is_in = is_in;

        INIT_LIST_HEAD(&mep->req_list);

        sprintf(mep->name, "ep%d%s", epnum,
                !epnum ? "" : (is_in ? "in" : "out"));

        mep->ep.name = mep->name;
        INIT_LIST_HEAD(&mep->ep.ep_list);

        /* initialize maxpacket as SS */
        if (!epnum) {
                usb_ep_set_maxpacket_limit(&mep->ep, 512);
                mep->ep.caps.type_control = true;
                mep->ep.ops = &mtu3_ep0_ops;
                mtu->g.ep0 = &mep->ep;
        } else {
                usb_ep_set_maxpacket_limit(&mep->ep, 1024);
                mep->ep.caps.type_iso = true;
                mep->ep.caps.type_bulk = true;
                mep->ep.caps.type_int = true;
                mep->ep.ops = &mtu3_ep_ops;
                list_add_tail(&mep->ep.ep_list, &mtu->g.ep_list);
        }

        dev_dbg(mtu->dev, "%s, name=%s, maxp=%d\n", __func__, mep->ep.name,
                 mep->ep.maxpacket);

        if (!epnum) {
                mep->ep.caps.dir_in = true;
                mep->ep.caps.dir_out = true;
        } else if (is_in) {
                mep->ep.caps.dir_in = true;
        } else {
                mep->ep.caps.dir_out = true;
        }
}

static void mtu3_gadget_init_eps(struct mtu3 *mtu)
{
        u8 epnum;

        /* initialize endpoint list just once */
        INIT_LIST_HEAD(&(mtu->g.ep_list));

        dev_dbg(mtu->dev, "%s num_eps(1 for a pair of tx&rx ep)=%d\n",
                __func__, mtu->num_eps);

        init_hw_ep(mtu, mtu->ep0, 0, 0);
        for (epnum = 1; epnum < mtu->num_eps; epnum++) {
                init_hw_ep(mtu, mtu->in_eps + epnum, epnum, 1);
                init_hw_ep(mtu, mtu->out_eps + epnum, epnum, 0);
        }
}

int mtu3_gadget_setup(struct mtu3 *mtu)
{
        mtu->g.ops = &mtu3_gadget_ops;
        mtu->g.max_speed = mtu->max_speed;
        mtu->g.speed = USB_SPEED_UNKNOWN;
        mtu->g.sg_supported = 0;
        mtu->g.name = MTU3_DRIVER_NAME;
        mtu->g.irq = mtu->irq;
        mtu->is_active = 0;
        mtu->delayed_status = false;

        mtu3_gadget_init_eps(mtu);

        return usb_add_gadget_udc(mtu->dev, &mtu->g);
}

void mtu3_gadget_cleanup(struct mtu3 *mtu)
{
        usb_del_gadget_udc(&mtu->g);
}

void mtu3_gadget_resume(struct mtu3 *mtu)
{
        dev_dbg(mtu->dev, "gadget RESUME\n");
        if (mtu->async_callbacks && mtu->gadget_driver && mtu->gadget_driver->resume) {
                spin_unlock(&mtu->lock);
                mtu->gadget_driver->resume(&mtu->g);
                spin_lock(&mtu->lock);
        }
}

/* called when SOF packets stop for 3+ msec or enters U3 */
void mtu3_gadget_suspend(struct mtu3 *mtu)
{
        dev_dbg(mtu->dev, "gadget SUSPEND\n");
        if (mtu->async_callbacks && mtu->gadget_driver && mtu->gadget_driver->suspend) {
                spin_unlock(&mtu->lock);
                mtu->gadget_driver->suspend(&mtu->g);
                spin_lock(&mtu->lock);
        }
}

/* called when VBUS drops below session threshold, and in other cases */
void mtu3_gadget_disconnect(struct mtu3 *mtu)
{
        dev_dbg(mtu->dev, "gadget DISCONNECT\n");
        if (mtu->async_callbacks && mtu->gadget_driver && mtu->gadget_driver->disconnect) {
                spin_unlock(&mtu->lock);
                mtu->gadget_driver->disconnect(&mtu->g);
                spin_lock(&mtu->lock);
        }

        mtu3_state_reset(mtu);
        usb_gadget_set_state(&mtu->g, USB_STATE_NOTATTACHED);
}

void mtu3_gadget_reset(struct mtu3 *mtu)
{
        dev_dbg(mtu->dev, "gadget RESET\n");

        /* report disconnect, if we didn't flush EP state */
        if (mtu->g.speed != USB_SPEED_UNKNOWN)
                mtu3_gadget_disconnect(mtu);
        else
                mtu3_state_reset(mtu);
}