// SPDX-License-Identifier: GPL-2.0
/*
 * Cadence USBSS DRD Driver - gadget side.
 *
 * Copyright (C) 2018 Cadence Design Systems.
 * Copyright (C) 2017-2018 NXP
 *
 * Authors: Pawel Jez <pjez@cadence.com>,
 *          Pawel Laszczak <pawell@cadence.com>
 *          Peter Chen <peter.chen@nxp.com>
 */

#include <linux/usb/composite.h>
#include <linux/iopoll.h>

#include "cdns3-gadget.h"
#include "cdns3-trace.h"

static struct usb_endpoint_descriptor cdns3_gadget_ep0_desc = {
        .bLength = USB_DT_ENDPOINT_SIZE,
        .bDescriptorType = USB_DT_ENDPOINT,
        .bmAttributes = USB_ENDPOINT_XFER_CONTROL,
};

/**
 * cdns3_ep0_run_transfer - Do transfer on default endpoint hardware
 * @priv_dev: extended gadget object
 * @dma_addr: physical address where data is/will be stored
 * @length: data length
 * @erdy: set it to 1 when ERDY packet should be sent -
 *        exit from flow control state
 * @zlp: add zero length packet
 */
static void cdns3_ep0_run_transfer(struct cdns3_device *priv_dev,
                                   dma_addr_t dma_addr,
                                   unsigned int length, int erdy, int zlp)
{
        struct cdns3_usb_regs __iomem *regs = priv_dev->regs;
        struct cdns3_endpoint *priv_ep = priv_dev->eps[0];

        priv_ep->trb_pool[0].buffer = cpu_to_le32(TRB_BUFFER(dma_addr));
        priv_ep->trb_pool[0].length = cpu_to_le32(TRB_LEN(length));

        if (zlp) {
                priv_ep->trb_pool[0].control = cpu_to_le32(TRB_CYCLE | TRB_TYPE(TRB_NORMAL));
                priv_ep->trb_pool[1].buffer = cpu_to_le32(TRB_BUFFER(dma_addr));
                priv_ep->trb_pool[1].length = cpu_to_le32(TRB_LEN(0));
                priv_ep->trb_pool[1].control = cpu_to_le32(TRB_CYCLE | TRB_IOC |
                    TRB_TYPE(TRB_NORMAL));
        } else {
                priv_ep->trb_pool[0].control = cpu_to_le32(TRB_CYCLE | TRB_IOC |
                    TRB_TYPE(TRB_NORMAL));
                priv_ep->trb_pool[1].control = 0;
        }

        trace_cdns3_prepare_trb(priv_ep, priv_ep->trb_pool);

        cdns3_select_ep(priv_dev, priv_dev->ep0_data_dir);

        writel(EP_STS_TRBERR, &regs->ep_sts);
        writel(EP_TRADDR_TRADDR(priv_ep->trb_pool_dma), &regs->ep_traddr);
        trace_cdns3_doorbell_ep0(priv_dev->ep0_data_dir ? "ep0in" : "ep0out",
                                 readl(&regs->ep_traddr));

        /* TRB should be prepared before starting transfer. */
        writel(EP_CMD_DRDY, &regs->ep_cmd);

        /* Resume controller before arming transfer. */
        __cdns3_gadget_wakeup(priv_dev);

        if (erdy)
                writel(EP_CMD_ERDY, &priv_dev->regs->ep_cmd);
}

/**
 * cdns3_ep0_delegate_req - Returns status of handling setup packet
 * Setup is handled by gadget driver
 * @priv_dev: extended gadget object
 * @ctrl_req: pointer to received setup packet
 *
 * Returns zero on success or negative value on failure
 */
static int cdns3_ep0_delegate_req(struct cdns3_device *priv_dev,
                                  struct usb_ctrlrequest *ctrl_req)
{
        int ret;

        spin_unlock(&priv_dev->lock);
        priv_dev->setup_pending = 1;
        ret = priv_dev->gadget_driver->setup(&priv_dev->gadget, ctrl_req);
        priv_dev->setup_pending = 0;
        spin_lock(&priv_dev->lock);
        return ret;
}

static void cdns3_prepare_setup_packet(struct cdns3_device *priv_dev)
{
        priv_dev->ep0_data_dir = 0;
        priv_dev->ep0_stage = CDNS3_SETUP_STAGE;
        cdns3_ep0_run_transfer(priv_dev, priv_dev->setup_dma,
                               sizeof(struct usb_ctrlrequest), 0, 0);
}

static void cdns3_ep0_complete_setup(struct cdns3_device *priv_dev,
                                     u8 send_stall, u8 send_erdy)
{
        struct cdns3_endpoint *priv_ep = priv_dev->eps[0];
        struct usb_request *request;

        request = cdns3_next_request(&priv_ep->pending_req_list);
        if (request)
                list_del_init(&request->list);

        if (send_stall) {
                trace_cdns3_halt(priv_ep, send_stall, 0);
                /* set_stall on ep0 */
                cdns3_select_ep(priv_dev, 0x00);
                writel(EP_CMD_SSTALL, &priv_dev->regs->ep_cmd);
        } else {
                cdns3_prepare_setup_packet(priv_dev);
        }

        priv_dev->ep0_stage = CDNS3_SETUP_STAGE;
        writel((send_erdy ? EP_CMD_ERDY : 0) | EP_CMD_REQ_CMPL,
               &priv_dev->regs->ep_cmd);
}

/**
 * cdns3_req_ep0_set_configuration - Handling of SET_CONFIG standard USB request
 * @priv_dev: extended gadget object
 * @ctrl_req: pointer to received setup packet
 *
 * Returns 0 if success, USB_GADGET_DELAYED_STATUS on deferred status stage,
 * error code on error
 */
static int cdns3_req_ep0_set_configuration(struct cdns3_device *priv_dev,
                                           struct usb_ctrlrequest *ctrl_req)
{
        enum usb_device_state device_state = priv_dev->gadget.state;
        u32 config = le16_to_cpu(ctrl_req->wValue);
        int result = 0;

        switch (device_state) {
        case USB_STATE_ADDRESS:
                result = cdns3_ep0_delegate_req(priv_dev, ctrl_req);

                if (result || !config)
                        goto reset_config;

                break;
        case USB_STATE_CONFIGURED:
                result = cdns3_ep0_delegate_req(priv_dev, ctrl_req);
                if (!config && !result)
                        goto reset_config;

                break;
        default:
                return -EINVAL;
        }

        return 0;

reset_config:
        if (result != USB_GADGET_DELAYED_STATUS)
                cdns3_hw_reset_eps_config(priv_dev);

        usb_gadget_set_state(&priv_dev->gadget,
                             USB_STATE_ADDRESS);

        return result;
}

/**
 * cdns3_req_ep0_set_address - Handling of SET_ADDRESS standard USB request
 * @priv_dev: extended gadget object
 * @ctrl_req: pointer to received setup packet
 *
 * Returns 0 if success, error code on error
 */
static int cdns3_req_ep0_set_address(struct cdns3_device *priv_dev,
                                     struct usb_ctrlrequest *ctrl_req)
{
        enum usb_device_state device_state = priv_dev->gadget.state;
        u32 reg;
        u32 addr;

        addr = le16_to_cpu(ctrl_req->wValue);

        if (addr > USB_DEVICE_MAX_ADDRESS) {
                dev_err(priv_dev->dev,
                        "Device address (%d) cannot be greater than %d\n",
                        addr, USB_DEVICE_MAX_ADDRESS);
                return -EINVAL;
        }

        if (device_state == USB_STATE_CONFIGURED) {
                dev_err(priv_dev->dev,
                        "can't set_address from configured state\n");
                return -EINVAL;
        }

        reg = readl(&priv_dev->regs->usb_cmd);

        writel(reg | USB_CMD_FADDR(addr) | USB_CMD_SET_ADDR,
               &priv_dev->regs->usb_cmd);

        usb_gadget_set_state(&priv_dev->gadget,
                             (addr ? USB_STATE_ADDRESS : USB_STATE_DEFAULT));

        return 0;
}

/**
 * cdns3_req_ep0_get_status - Handling of GET_STATUS standard USB request
 * @priv_dev: extended gadget object
 * @ctrl: pointer to received setup packet
 *
 * Returns 0 if success, error code on error
 */
static int cdns3_req_ep0_get_status(struct cdns3_device *priv_dev,
                                    struct usb_ctrlrequest *ctrl)
{
        struct cdns3_endpoint *priv_ep;
        __le16 *response_pkt;
        u16 usb_status = 0;
        u32 recip;
        u8 index;

        recip = ctrl->bRequestType & USB_RECIP_MASK;

        switch (recip) {
        case USB_RECIP_DEVICE:
                /* self powered */
                if (priv_dev->is_selfpowered)
                        usb_status = BIT(USB_DEVICE_SELF_POWERED);

                if (priv_dev->wake_up_flag)
                        usb_status |= BIT(USB_DEVICE_REMOTE_WAKEUP);

                if (priv_dev->gadget.speed != USB_SPEED_SUPER)
                        break;

                if (priv_dev->u1_allowed)
                        usb_status |= BIT(USB_DEV_STAT_U1_ENABLED);

                if (priv_dev->u2_allowed)
                        usb_status |= BIT(USB_DEV_STAT_U2_ENABLED);

                break;
        case USB_RECIP_INTERFACE:
                return cdns3_ep0_delegate_req(priv_dev, ctrl);
        case USB_RECIP_ENDPOINT:
                index = cdns3_ep_addr_to_index(le16_to_cpu(ctrl->wIndex));
                priv_ep = priv_dev->eps[index];

                /* check if endpoint is stalled or stall is pending */
                cdns3_select_ep(priv_dev, le16_to_cpu(ctrl->wIndex));
                if (EP_STS_STALL(readl(&priv_dev->regs->ep_sts)) ||
                    (priv_ep->flags & EP_STALL_PENDING))
                        usb_status =  BIT(USB_ENDPOINT_HALT);
                break;
        default:
                return -EINVAL;
        }

        response_pkt = (__le16 *)priv_dev->setup_buf;
        *response_pkt = cpu_to_le16(usb_status);

        cdns3_ep0_run_transfer(priv_dev, priv_dev->setup_dma,
                               sizeof(*response_pkt), 1, 0);
        return 0;
}

static int cdns3_ep0_feature_handle_device(struct cdns3_device *priv_dev,
                                           struct usb_ctrlrequest *ctrl,
                                           int set)
{
        enum usb_device_state state;
        enum usb_device_speed speed;
        int ret = 0;
        u32 wValue;
        u16 tmode;

        wValue = le16_to_cpu(ctrl->wValue);
        state = priv_dev->gadget.state;
        speed = priv_dev->gadget.speed;

        switch (wValue) {
        case USB_DEVICE_REMOTE_WAKEUP:
                priv_dev->wake_up_flag = !!set;
                break;
        case USB_DEVICE_U1_ENABLE:
                if (state != USB_STATE_CONFIGURED || speed != USB_SPEED_SUPER)
                        return -EINVAL;

                priv_dev->u1_allowed = !!set;
                break;
        case USB_DEVICE_U2_ENABLE:
                if (state != USB_STATE_CONFIGURED || speed != USB_SPEED_SUPER)
                        return -EINVAL;

                priv_dev->u2_allowed = !!set;
                break;
        case USB_DEVICE_LTM_ENABLE:
                ret = -EINVAL;
                break;
        case USB_DEVICE_TEST_MODE:
                if (state != USB_STATE_CONFIGURED || speed > USB_SPEED_HIGH)
                        return -EINVAL;

                tmode = le16_to_cpu(ctrl->wIndex);

                if (!set || (tmode & 0xff) != 0)
                        return -EINVAL;

                tmode >>= 8;
                switch (tmode) {
                case USB_TEST_J:
                case USB_TEST_K:
                case USB_TEST_SE0_NAK:
                case USB_TEST_PACKET:
                        cdns3_set_register_bit(&priv_dev->regs->usb_cmd,
                                               USB_CMD_STMODE |
                                               USB_STS_TMODE_SEL(tmode - 1));
                        break;
                default:
                        ret = -EINVAL;
                }
                break;
        default:
                ret = -EINVAL;
        }

        return ret;
}

static int cdns3_ep0_feature_handle_intf(struct cdns3_device *priv_dev,
                                         struct usb_ctrlrequest *ctrl,
                                         int set)
{
        u32 wValue;
        int ret = 0;

        wValue = le16_to_cpu(ctrl->wValue);

        switch (wValue) {
        case USB_INTRF_FUNC_SUSPEND:
                break;
        default:
                ret = -EINVAL;
        }

        return ret;
}

static int cdns3_ep0_feature_handle_endpoint(struct cdns3_device *priv_dev,
                                             struct usb_ctrlrequest *ctrl,
                                             int set)
{
        struct cdns3_endpoint *priv_ep;
        int ret = 0;
        u8 index;

        if (le16_to_cpu(ctrl->wValue) != USB_ENDPOINT_HALT)
                return -EINVAL;

        if (!(le16_to_cpu(ctrl->wIndex) & ~USB_DIR_IN))
                return 0;

        index = cdns3_ep_addr_to_index(le16_to_cpu(ctrl->wIndex));
        priv_ep = priv_dev->eps[index];

        cdns3_select_ep(priv_dev, le16_to_cpu(ctrl->wIndex));

        if (set)
                __cdns3_gadget_ep_set_halt(priv_ep);
        else if (!(priv_ep->flags & EP_WEDGE))
                ret = __cdns3_gadget_ep_clear_halt(priv_ep);

        cdns3_select_ep(priv_dev, 0x00);

        return ret;
}

/**
 * cdns3_req_ep0_handle_feature -
 * Handling of GET/SET_FEATURE standard USB request
 *
 * @priv_dev: extended gadget object
 * @ctrl: pointer to received setup packet
 * @set: must be set to 1 for SET_FEATURE request
 *
 * Returns 0 if success, error code on error
 */
static int cdns3_req_ep0_handle_feature(struct cdns3_device *priv_dev,
                                        struct usb_ctrlrequest *ctrl,
                                        int set)
{
        int ret = 0;
        u32 recip;

        recip = ctrl->bRequestType & USB_RECIP_MASK;

        switch (recip) {
        case USB_RECIP_DEVICE:
                ret = cdns3_ep0_feature_handle_device(priv_dev, ctrl, set);
                break;
        case USB_RECIP_INTERFACE:
                ret = cdns3_ep0_feature_handle_intf(priv_dev, ctrl, set);
                break;
        case USB_RECIP_ENDPOINT:
                ret = cdns3_ep0_feature_handle_endpoint(priv_dev, ctrl, set);
                break;
        default:
                return -EINVAL;
        }

        return ret;
}

/**
 * cdns3_req_ep0_set_sel - Handling of SET_SEL standard USB request
 * @priv_dev: extended gadget object
 * @ctrl_req: pointer to received setup packet
 *
 * Returns 0 if success, error code on error
 */
static int cdns3_req_ep0_set_sel(struct cdns3_device *priv_dev,
                                 struct usb_ctrlrequest *ctrl_req)
{
        if (priv_dev->gadget.state < USB_STATE_ADDRESS)
                return -EINVAL;

        if (le16_to_cpu(ctrl_req->wLength) != 6) {
                dev_err(priv_dev->dev, "Set SEL should be 6 bytes, got %d\n",
                        ctrl_req->wLength);
                return -EINVAL;
        }

        cdns3_ep0_run_transfer(priv_dev, priv_dev->setup_dma, 6, 1, 0);
        return 0;
}

/**
 * cdns3_req_ep0_set_isoch_delay -
 * Handling of GET_ISOCH_DELAY standard USB request
 * @priv_dev: extended gadget object
 * @ctrl_req: pointer to received setup packet
 *
 * Returns 0 if success, error code on error
 */
static int cdns3_req_ep0_set_isoch_delay(struct cdns3_device *priv_dev,
                                         struct usb_ctrlrequest *ctrl_req)
{
        if (ctrl_req->wIndex || ctrl_req->wLength)
                return -EINVAL;

        priv_dev->isoch_delay = le16_to_cpu(ctrl_req->wValue);

        return 0;
}

/**
 * cdns3_ep0_standard_request - Handling standard USB requests
 * @priv_dev: extended gadget object
 * @ctrl_req: pointer to received setup packet
 *
 * Returns 0 if success, error code on error
 */
static int cdns3_ep0_standard_request(struct cdns3_device *priv_dev,
                                      struct usb_ctrlrequest *ctrl_req)
{
        int ret;

        switch (ctrl_req->bRequest) {
        case USB_REQ_SET_ADDRESS:
                ret = cdns3_req_ep0_set_address(priv_dev, ctrl_req);
                break;
        case USB_REQ_SET_CONFIGURATION:
                ret = cdns3_req_ep0_set_configuration(priv_dev, ctrl_req);
                break;
        case USB_REQ_GET_STATUS:
                ret = cdns3_req_ep0_get_status(priv_dev, ctrl_req);
                break;
        case USB_REQ_CLEAR_FEATURE:
                ret = cdns3_req_ep0_handle_feature(priv_dev, ctrl_req, 0);
                break;
        case USB_REQ_SET_FEATURE:
                ret = cdns3_req_ep0_handle_feature(priv_dev, ctrl_req, 1);
                break;
        case USB_REQ_SET_SEL:
                ret = cdns3_req_ep0_set_sel(priv_dev, ctrl_req);
                break;
        case USB_REQ_SET_ISOCH_DELAY:
                ret = cdns3_req_ep0_set_isoch_delay(priv_dev, ctrl_req);
                break;
        default:
                ret = cdns3_ep0_delegate_req(priv_dev, ctrl_req);
                break;
        }

        return ret;
}

static void __pending_setup_status_handler(struct cdns3_device *priv_dev)
{
        struct usb_request *request = priv_dev->pending_status_request;

        if (priv_dev->status_completion_no_call && request &&
            request->complete) {
                request->complete(&priv_dev->eps[0]->endpoint, request);
                priv_dev->status_completion_no_call = 0;
        }
}

void cdns3_pending_setup_status_handler(struct work_struct *work)
{
        struct cdns3_device *priv_dev = container_of(work, struct cdns3_device,
                        pending_status_wq);
        unsigned long flags;

        spin_lock_irqsave(&priv_dev->lock, flags);
        __pending_setup_status_handler(priv_dev);
        spin_unlock_irqrestore(&priv_dev->lock, flags);
}

/**
 * cdns3_ep0_setup_phase - Handling setup USB requests
 * @priv_dev: extended gadget object
 */
static void cdns3_ep0_setup_phase(struct cdns3_device *priv_dev)
{
        struct usb_ctrlrequest *ctrl = priv_dev->setup_buf;
        struct cdns3_endpoint *priv_ep = priv_dev->eps[0];
        int result;

        priv_dev->ep0_data_dir = ctrl->bRequestType & USB_DIR_IN;

        trace_cdns3_ctrl_req(ctrl);

        if (!list_empty(&priv_ep->pending_req_list)) {
                struct usb_request *request;

                request = cdns3_next_request(&priv_ep->pending_req_list);
                priv_ep->dir = priv_dev->ep0_data_dir;
                cdns3_gadget_giveback(priv_ep, to_cdns3_request(request),
                                      -ECONNRESET);
        }

        if (le16_to_cpu(ctrl->wLength))
                priv_dev->ep0_stage = CDNS3_DATA_STAGE;
        else
                priv_dev->ep0_stage = CDNS3_STATUS_STAGE;

        if ((ctrl->bRequestType & USB_TYPE_MASK) == USB_TYPE_STANDARD)
                result = cdns3_ep0_standard_request(priv_dev, ctrl);
        else
                result = cdns3_ep0_delegate_req(priv_dev, ctrl);

        if (result == USB_GADGET_DELAYED_STATUS)
                return;

        if (result < 0)
                cdns3_ep0_complete_setup(priv_dev, 1, 1);
        else if (priv_dev->ep0_stage == CDNS3_STATUS_STAGE)
                cdns3_ep0_complete_setup(priv_dev, 0, 1);
}

static void cdns3_transfer_completed(struct cdns3_device *priv_dev)
{
        struct cdns3_endpoint *priv_ep = priv_dev->eps[0];

        if (!list_empty(&priv_ep->pending_req_list)) {
                struct usb_request *request;

                trace_cdns3_complete_trb(priv_ep, priv_ep->trb_pool);
                request = cdns3_next_request(&priv_ep->pending_req_list);

                request->actual =
                        TRB_LEN(le32_to_cpu(priv_ep->trb_pool->length));

                priv_ep->dir = priv_dev->ep0_data_dir;
                cdns3_gadget_giveback(priv_ep, to_cdns3_request(request), 0);
        }

        cdns3_ep0_complete_setup(priv_dev, 0, 0);
}

/**
 * cdns3_check_new_setup - Check if controller receive new SETUP packet.
 * @priv_dev: extended gadget object
 *
 * The SETUP packet can be kept in on-chip memory or in system memory.
 */
static bool cdns3_check_new_setup(struct cdns3_device *priv_dev)
{
        u32 ep_sts_reg;

        cdns3_select_ep(priv_dev, USB_DIR_OUT);
        ep_sts_reg = readl(&priv_dev->regs->ep_sts);

        return !!(ep_sts_reg & (EP_STS_SETUP | EP_STS_STPWAIT));
}

/**
 * cdns3_check_ep0_interrupt_proceed - Processes interrupt related to endpoint 0
 * @priv_dev: extended gadget object
 * @dir: USB_DIR_IN for IN direction, USB_DIR_OUT for OUT direction
 */
void cdns3_check_ep0_interrupt_proceed(struct cdns3_device *priv_dev, int dir)
{
        u32 ep_sts_reg;

        cdns3_select_ep(priv_dev, dir);

        ep_sts_reg = readl(&priv_dev->regs->ep_sts);
        writel(ep_sts_reg, &priv_dev->regs->ep_sts);

        trace_cdns3_ep0_irq(priv_dev, ep_sts_reg);

        __pending_setup_status_handler(priv_dev);

        if (ep_sts_reg & EP_STS_SETUP)
                priv_dev->wait_for_setup = 1;

        if (priv_dev->wait_for_setup && ep_sts_reg & EP_STS_IOC) {
                priv_dev->wait_for_setup = 0;
                cdns3_ep0_setup_phase(priv_dev);
        } else if ((ep_sts_reg & EP_STS_IOC) || (ep_sts_reg & EP_STS_ISP)) {
                priv_dev->ep0_data_dir = dir;
                cdns3_transfer_completed(priv_dev);
        }

        if (ep_sts_reg & EP_STS_DESCMIS) {
                if (dir == 0 && !priv_dev->setup_pending)
                        cdns3_prepare_setup_packet(priv_dev);
        }
}

/**
 * cdns3_gadget_ep0_enable
 * @ep: pointer to endpoint zero object
 * @desc: pointer to usb endpoint descriptor
 *
 * Function shouldn't be called by gadget driver,
 * endpoint 0 is allways active
 */
static int cdns3_gadget_ep0_enable(struct usb_ep *ep,
                                   const struct usb_endpoint_descriptor *desc)
{
        return -EINVAL;
}

/**
 * cdns3_gadget_ep0_disable
 * @ep: pointer to endpoint zero object
 *
 * Function shouldn't be called by gadget driver,
 * endpoint 0 is allways active
 */
static int cdns3_gadget_ep0_disable(struct usb_ep *ep)
{
        return -EINVAL;
}

/**
 * cdns3_gadget_ep0_set_halt
 * @ep: pointer to endpoint zero object
 * @value: 1 for set stall, 0 for clear stall
 *
 * Returns 0
 */
static int cdns3_gadget_ep0_set_halt(struct usb_ep *ep, int value)
{
        /* TODO */
        return 0;
}

/**
 * cdns3_gadget_ep0_queue - Transfer data on endpoint zero
 * @ep: pointer to endpoint zero object
 * @request: pointer to request object
 * @gfp_flags: gfp flags
 *
 * Returns 0 on success, error code elsewhere
 */
static int cdns3_gadget_ep0_queue(struct usb_ep *ep,
                                  struct usb_request *request,
                                  gfp_t gfp_flags)
{
        struct cdns3_endpoint *priv_ep = ep_to_cdns3_ep(ep);
        struct cdns3_device *priv_dev = priv_ep->cdns3_dev;
        unsigned long flags;
        int ret = 0;
        u8 zlp = 0;
        int i;

        spin_lock_irqsave(&priv_dev->lock, flags);
        trace_cdns3_ep0_queue(priv_dev, request);

        /* cancel the request if controller receive new SETUP packet. */
        if (cdns3_check_new_setup(priv_dev)) {
                spin_unlock_irqrestore(&priv_dev->lock, flags);
                return -ECONNRESET;
        }

        /* send STATUS stage. Should be called only for SET_CONFIGURATION */
        if (priv_dev->ep0_stage == CDNS3_STATUS_STAGE) {
                u32 val;

                cdns3_select_ep(priv_dev, 0x00);

                /*
                 * Configure all non-control EPs which are not enabled by class driver
                 */
                for (i = 0; i < CDNS3_ENDPOINTS_MAX_COUNT; i++) {
                        priv_ep = priv_dev->eps[i];
                        if (priv_ep && priv_ep->flags & EP_CLAIMED &&
                            !(priv_ep->flags & EP_ENABLED))
                                cdns3_ep_config(priv_ep, 0);
                }

                cdns3_set_hw_configuration(priv_dev);
                cdns3_ep0_complete_setup(priv_dev, 0, 1);
                /* wait until configuration set */
                ret = readl_poll_timeout_atomic(&priv_dev->regs->usb_sts, val,
                                          val & USB_STS_CFGSTS_MASK, 1, 100);
                if (ret == -ETIMEDOUT)
                        dev_warn(priv_dev->dev, "timeout for waiting configuration set\n");

                request->actual = 0;
                priv_dev->status_completion_no_call = true;
                priv_dev->pending_status_request = request;
                usb_gadget_set_state(&priv_dev->gadget, USB_STATE_CONFIGURED);
                spin_unlock_irqrestore(&priv_dev->lock, flags);

                /*
                 * Since there is no completion interrupt for status stage,
                 * it needs to call ->completion in software after
                 * ep0_queue is back.
                 */
                queue_work(system_freezable_wq, &priv_dev->pending_status_wq);
                return ret;
        }

        if (!list_empty(&priv_ep->pending_req_list)) {
                dev_err(priv_dev->dev,
                        "can't handle multiple requests for ep0\n");
                spin_unlock_irqrestore(&priv_dev->lock, flags);
                return -EBUSY;
        }

        ret = usb_gadget_map_request_by_dev(priv_dev->sysdev, request,
                                            priv_dev->ep0_data_dir);
        if (ret) {
                spin_unlock_irqrestore(&priv_dev->lock, flags);
                dev_err(priv_dev->dev, "failed to map request\n");
                return -EINVAL;
        }

        request->status = -EINPROGRESS;
        list_add_tail(&request->list, &priv_ep->pending_req_list);

        if (request->zero && request->length &&
            (request->length % ep->maxpacket == 0))
                zlp = 1;

        cdns3_ep0_run_transfer(priv_dev, request->dma, request->length, 1, zlp);

        spin_unlock_irqrestore(&priv_dev->lock, flags);

        return ret;
}

/**
 * cdns3_gadget_ep_set_wedge - Set wedge on selected endpoint
 * @ep: endpoint object
 *
 * Returns 0
 */
int cdns3_gadget_ep_set_wedge(struct usb_ep *ep)
{
        struct cdns3_endpoint *priv_ep = ep_to_cdns3_ep(ep);
        struct cdns3_device *priv_dev = priv_ep->cdns3_dev;

        dev_dbg(priv_dev->dev, "Wedge for %s\n", ep->name);
        cdns3_gadget_ep_set_halt(ep, 1);
        priv_ep->flags |= EP_WEDGE;

        return 0;
}

static const struct usb_ep_ops cdns3_gadget_ep0_ops = {
        .enable = cdns3_gadget_ep0_enable,
        .disable = cdns3_gadget_ep0_disable,
        .alloc_request = cdns3_gadget_ep_alloc_request,
        .free_request = cdns3_gadget_ep_free_request,
        .queue = cdns3_gadget_ep0_queue,
        .dequeue = cdns3_gadget_ep_dequeue,
        .set_halt = cdns3_gadget_ep0_set_halt,
        .set_wedge = cdns3_gadget_ep_set_wedge,
};

/**
 * cdns3_ep0_config - Configures default endpoint
 * @priv_dev: extended gadget object
 *
 * Functions sets parameters: maximal packet size and enables interrupts
 */
void cdns3_ep0_config(struct cdns3_device *priv_dev)
{
        struct cdns3_usb_regs __iomem *regs;
        struct cdns3_endpoint *priv_ep;
        u32 max_packet_size = 64;
        u32 ep_cfg;

        regs = priv_dev->regs;

        if (priv_dev->gadget.speed == USB_SPEED_SUPER)
                max_packet_size = 512;

        priv_ep = priv_dev->eps[0];

        if (!list_empty(&priv_ep->pending_req_list)) {
                struct usb_request *request;

                request = cdns3_next_request(&priv_ep->pending_req_list);
                list_del_init(&request->list);
        }

        priv_dev->u1_allowed = 0;
        priv_dev->u2_allowed = 0;

        priv_dev->gadget.ep0->maxpacket = max_packet_size;
        cdns3_gadget_ep0_desc.wMaxPacketSize = cpu_to_le16(max_packet_size);

        /* init ep out */
        cdns3_select_ep(priv_dev, USB_DIR_OUT);

        if (priv_dev->dev_ver >= DEV_VER_V3) {
                cdns3_set_register_bit(&priv_dev->regs->dtrans,
                                       BIT(0) | BIT(16));
                cdns3_set_register_bit(&priv_dev->regs->tdl_from_trb,
                                       BIT(0) | BIT(16));
        }

        ep_cfg = EP_CFG_ENABLE | EP_CFG_MAXPKTSIZE(max_packet_size);

        if (!(priv_ep->flags & EP_CONFIGURED))
                writel(ep_cfg, &regs->ep_cfg);

        writel(EP_STS_EN_SETUPEN | EP_STS_EN_DESCMISEN | EP_STS_EN_TRBERREN,
               &regs->ep_sts_en);

        /* init ep in */
        cdns3_select_ep(priv_dev, USB_DIR_IN);

        if (!(priv_ep->flags & EP_CONFIGURED))
                writel(ep_cfg, &regs->ep_cfg);

        priv_ep->flags |= EP_CONFIGURED;

        writel(EP_STS_EN_SETUPEN | EP_STS_EN_TRBERREN, &regs->ep_sts_en);

        cdns3_set_register_bit(&regs->usb_conf, USB_CONF_U1DS | USB_CONF_U2DS);
}

/**
 * cdns3_init_ep0 - Initializes software endpoint 0 of gadget
 * @priv_dev: extended gadget object
 * @priv_ep: extended endpoint object
 *
 * Returns 0 on success else error code.
 */
int cdns3_init_ep0(struct cdns3_device *priv_dev,
                   struct cdns3_endpoint *priv_ep)
{
        sprintf(priv_ep->name, "ep0");

        /* fill linux fields */
        priv_ep->endpoint.ops = &cdns3_gadget_ep0_ops;
        priv_ep->endpoint.maxburst = 1;
        usb_ep_set_maxpacket_limit(&priv_ep->endpoint,
                                   CDNS3_EP0_MAX_PACKET_LIMIT);
        priv_ep->endpoint.address = 0;
        priv_ep->endpoint.caps.type_control = 1;
        priv_ep->endpoint.caps.dir_in = 1;
        priv_ep->endpoint.caps.dir_out = 1;
        priv_ep->endpoint.name = priv_ep->name;
        priv_ep->endpoint.desc = &cdns3_gadget_ep0_desc;
        priv_dev->gadget.ep0 = &priv_ep->endpoint;
        priv_ep->type = USB_ENDPOINT_XFER_CONTROL;

        return cdns3_allocate_trb_pool(priv_ep);
}