// SPDX-License-Identifier: GPL-2.0+
/*
* @file hv_drv_UsbFunctionHid.c (f_hid.c)
* @brief USB HID function driver. 
*
* @author HiView SoC Software Team
* @version 1.0.0
* @date 2022-06-15
*/

#include "hv_drv_UsbGadgetComposite.h"
#include "hv_drv_UsbErr.h"
#include "hv_vos_Comm.h"
#include "hv_drv_UsbGadgetHid.h"
#include "hv_drv_UsbUtilHid.h"
#include "hv_drv_UsbApiHid.h"
#include "hv_drv_UsbHid.h"
#include "hv_drv_UsbDefines.h"
#include "hv_drv_UsbUtilFunction.h"
#include "hv_drv_UsbGadgetConfig.h"


#define HIDG_MINORS                 4

static int major, minors;
static struct class *hidg_class;
const char const_buffer[] = {0xde,0xad,0xbe,0xef};

/*-------------------------------------------------------------------------*/
/*                            HID gadget struct                            */

struct f_hidg_req_list {
    struct usb_request    *req;
    unsigned int        pos;
    struct list_head     list;
};

struct f_hidg {
    /* configuration */
    unsigned char            bInterfaceSubClass;
    unsigned char            bInterfaceProtocol;
    unsigned char            protocol;
    unsigned short           report_desc_length;
    char                     *report_desc;
    unsigned short           report_length;

    /* recv report */
    struct list_head         completed_out_req;
    spinlock_t               read_spinlock;
    wait_queue_head_t        read_queue;
    unsigned int             qlen;

    /* send report */
    spinlock_t               write_spinlock;
    bool                     write_pending;
    wait_queue_head_t        write_queue;
    struct usb_request       *req;

    int                      minor;
    struct cdev              cdev;
    struct usb_function      func;

    struct usb_ep            *in_ep;
    struct usb_ep            *out_ep;
};

static inline struct f_hidg *func_to_hidg(struct usb_function *f)
{
    return container_of(f, struct f_hidg, func);
}

/*-------------------------------------------------------------------------*/
/*                           Static descriptors                            */

static struct usb_interface_descriptor hidg_interface_desc = {
    .bLength                = sizeof hidg_interface_desc,
    .bDescriptorType        = USB_DT_INTERFACE,
    /* .bInterfaceNumber    = DYNAMIC */
    .bAlternateSetting      = 0,
    .bNumEndpoints          = 2,
    .bInterfaceClass        = USB_CLASS_HID,
    /* .bInterfaceSubClass    = DYNAMIC */
    /* .bInterfaceProtocol    = DYNAMIC */
    /* .iInterface        = DYNAMIC */
};

static struct hid_descriptor hidg_desc = {
    .bLength                = sizeof hidg_desc,
    .bDescriptorType        = HID_DT_HID,
    .bcdHID                 = 0x0101,
    .bCountryCode           = 0x00,
    .bNumDescriptors        = 0x1,
    /*.desc[0].bDescriptorType    = DYNAMIC */
    /*.desc[0].wDescriptorLenght    = DYNAMIC */
};

/* Super-Speed Support */

static struct usb_endpoint_descriptor hidg_ss_in_ep_desc = {
    .bLength                = USB_DT_ENDPOINT_SIZE,
    .bDescriptorType        = USB_DT_ENDPOINT,
    .bEndpointAddress       = USB_DIR_IN,
    .bmAttributes           = USB_ENDPOINT_XFER_INT,
    /*.wMaxPacketSize    = DYNAMIC */
    .bInterval              = 4, /* FIXME: Add this field in the
                                    * HID gadget configuration?
                                    * (struct hidg_func_descriptor)
                                 */
};

static struct usb_ss_ep_comp_descriptor hidg_ss_in_comp_desc = {
    .bLength                = sizeof(hidg_ss_in_comp_desc),
    .bDescriptorType        = USB_DT_SS_ENDPOINT_COMP,

    /* .bMaxBurst           = 0, */
    /* .bmAttributes        = 0, */
    /* .wBytesPerInterval   = DYNAMIC */
};

static struct usb_endpoint_descriptor hidg_ss_out_ep_desc = {
    .bLength                = USB_DT_ENDPOINT_SIZE,
    .bDescriptorType        = USB_DT_ENDPOINT,
    .bEndpointAddress       = USB_DIR_OUT,
    .bmAttributes           = USB_ENDPOINT_XFER_INT,
    /*.wMaxPacketSize    = DYNAMIC */
    .bInterval              = 4, /* FIXME: Add this field in the
                                    * HID gadget configuration?
                                    * (struct hidg_func_descriptor)
                                 */
};

static struct usb_ss_ep_comp_descriptor hidg_ss_out_comp_desc = {
    .bLength                = sizeof(hidg_ss_out_comp_desc),
    .bDescriptorType        = USB_DT_SS_ENDPOINT_COMP,

    /* .bMaxBurst           = 0, */
    /* .bmAttributes        = 0, */
    /* .wBytesPerInterval   = DYNAMIC */
};

static struct usb_descriptor_header *hidg_ss_descriptors[] = {
    (struct usb_descriptor_header *)&hidg_interface_desc,
    (struct usb_descriptor_header *)&hidg_desc,
    (struct usb_descriptor_header *)&hidg_ss_in_ep_desc,
    (struct usb_descriptor_header *)&hidg_ss_in_comp_desc,
    (struct usb_descriptor_header *)&hidg_ss_out_ep_desc,
    (struct usb_descriptor_header *)&hidg_ss_out_comp_desc,
    NULL,
};

/* High-Speed Support */

static struct usb_endpoint_descriptor hidg_hs_in_ep_desc = {
    .bLength                = USB_DT_ENDPOINT_SIZE,
    .bDescriptorType        = USB_DT_ENDPOINT,
    .bEndpointAddress       = USB_DIR_IN,
    .bmAttributes           = USB_ENDPOINT_XFER_INT,
    /*.wMaxPacketSize    = DYNAMIC */
    .bInterval              = 4, /* FIXME: Add this field in the
                                    * HID gadget configuration?
                                    * (struct hidg_func_descriptor)
                                 */
};

static struct usb_endpoint_descriptor hidg_hs_out_ep_desc = {
    .bLength                = USB_DT_ENDPOINT_SIZE,
    .bDescriptorType        = USB_DT_ENDPOINT,
    .bEndpointAddress       = USB_DIR_OUT,
    .bmAttributes           = USB_ENDPOINT_XFER_INT,
    /*.wMaxPacketSize    = DYNAMIC */
    .bInterval              = 4, /* FIXME: Add this field in the
                                    * HID gadget configuration?
                                    * (struct hidg_func_descriptor)
                                 */
};

static struct usb_descriptor_header *hidg_hs_descriptors[] = {
    (struct usb_descriptor_header *)&hidg_interface_desc,
    (struct usb_descriptor_header *)&hidg_desc,
    (struct usb_descriptor_header *)&hidg_hs_in_ep_desc,
    (struct usb_descriptor_header *)&hidg_hs_out_ep_desc,
    NULL,
};

/* Full-Speed Support */

static struct usb_endpoint_descriptor hidg_fs_in_ep_desc = {
    .bLength                = USB_DT_ENDPOINT_SIZE,
    .bDescriptorType        = USB_DT_ENDPOINT,
    .bEndpointAddress       = USB_DIR_IN,
    .bmAttributes           = USB_ENDPOINT_XFER_INT,
    /*.wMaxPacketSize    = DYNAMIC */
    .bInterval              = 10, /* FIXME: Add this field in the
                                    * HID gadget configuration?
                                    * (struct hidg_func_descriptor)
                                  */
};

static struct usb_endpoint_descriptor hidg_fs_out_ep_desc = {
    .bLength                = USB_DT_ENDPOINT_SIZE,
    .bDescriptorType        = USB_DT_ENDPOINT,
    .bEndpointAddress       = USB_DIR_OUT,
    .bmAttributes           = USB_ENDPOINT_XFER_INT,
    /*.wMaxPacketSize    = DYNAMIC */
    .bInterval              = 10, /* FIXME: Add this field in the
                                    * HID gadget configuration?
                                    * (struct hidg_func_descriptor)
                                  */
};

static struct usb_descriptor_header *hidg_fs_descriptors[] = {
    (struct usb_descriptor_header *)&hidg_interface_desc,
    (struct usb_descriptor_header *)&hidg_desc,
    (struct usb_descriptor_header *)&hidg_fs_out_ep_desc,
    (struct usb_descriptor_header *)&hidg_fs_in_ep_desc,
    NULL,
};

/*-------------------------------------------------------------------------*/
/*                                 Strings                                 */

#define CT_FUNC_HID_IDX    0

static struct usb_string ct_func_string_defs[] = {
    [CT_FUNC_HID_IDX].s    = "HID Interface",
    {},            /* end of list */
};

static struct usb_gadget_strings ct_func_string_table = {
    .language    = 0x0409,    /* en-US */
    .strings    = ct_func_string_defs,
};

static struct usb_gadget_strings *ct_func_strings[] = {
    &ct_func_string_table,
    NULL,
};

/*-------------------------------------------------------------------------*/
/*                              Char Device                                */

ssize_t f_hidg_read(struct file *file, char *buffer,
            size_t count, loff_t *ptr)
{
    struct f_hidg *hidg = file->private_data;
    struct f_hidg_req_list *list;
    struct usb_request *req;
    unsigned long flags;
    int ret;

    if (!count)
        return 0;
    debug("f_hidg_read !\n");
    spin_lock_irqsave(&hidg->read_spinlock, flags);

#define READ_COND (!list_empty(&hidg->completed_out_req))

    /* wait for at least one buffer to complete */
    while (!READ_COND) {
        spin_unlock_irqrestore(&hidg->read_spinlock, flags);

        if (wait_event_interruptible(hidg->read_queue, READ_COND))
            return -ERESTARTSYS;

        spin_lock_irqsave(&hidg->read_spinlock, flags);
    }

    /* pick the first one */
    list = list_first_entry(&hidg->completed_out_req,
                struct f_hidg_req_list, list);

    /*
     * Remove this from list to protect it from beign free()
     * while host disables our function
     */
    list_del(&list->list);

    req = list->req;
    count = min_t(unsigned int, count, req->actual - list->pos);
    spin_unlock_irqrestore(&hidg->read_spinlock, flags);

    /* copy to user outside spinlock */
//    count -= copy_to_user(buffer, req->buf + list->pos, count);
    HV_MEMCPY(buffer,req->buf + list->pos,count);
        
    list->pos += count;

    /*
     * if this request is completely handled and transfered to
     * userspace, remove its entry from the list and requeue it
     * again. Otherwise, we will revisit it again upon the next
     * call, taking into account its current read position.
     */
    if (list->pos == req->actual) {
        kfree(list);

        req->length = hidg->report_length;
        ret = usb_ep_queue(hidg->out_ep, req, GFP_KERNEL);
        if (ret < 0) {
            free_ep_req(hidg->out_ep, req);
            return ret;
        }
    } else {
        spin_lock_irqsave(&hidg->read_spinlock, flags);
        list_add(&list->list, &hidg->completed_out_req);
        spin_unlock_irqrestore(&hidg->read_spinlock, flags);

        wake_up(&hidg->read_queue);
    }

    return count;
}

void f_hidg_req_complete(struct usb_ep *ep, struct usb_request *req)
{
    struct f_hidg *hidg = (struct f_hidg *)ep->driver_data;
    unsigned long flags;

    if (req->status != 0) {
        debug(
            "End Point Request ERROR: %d\n", req->status);
    }

    spin_lock_irqsave(&hidg->write_spinlock, flags);
    hidg->write_pending = 0;
    
    spin_unlock_irqrestore(&hidg->write_spinlock, flags);
    wake_up(&hidg->write_queue);
}
ssize_t f_write(struct    f_hidg *hidg, const char *buffer,
                size_t count, loff_t *offp){

    struct usb_request *req;
    unsigned long flags;
    ssize_t status = -ENOMEM;
    debug("f_hidg_write !\n");
    spin_lock_irqsave(&hidg->write_spinlock, flags);
    
#define WRITE_COND (!hidg->write_pending)
    try_again:
        /* write queue */
        while (!WRITE_COND) {
            spin_unlock_irqrestore(&hidg->write_spinlock, flags);
    
#if 0
            if (wait_event_interruptible_exclusive(
                    hidg->write_queue, WRITE_COND))
                return -ERESTARTSYS;
#endif
            spin_lock_irqsave(&hidg->write_spinlock, flags);
        }
    
        hidg->write_pending = 1;
        req = hidg->req;
        count  = min_t(unsigned, count, hidg->report_length);
    
        spin_unlock_irqrestore(&hidg->write_spinlock, flags);
        HV_MEMCPY(req->buf, buffer, count);
//        if (status != 0) {
//            debug("copy_from_user error\n");
//            status = -EINVAL;
//            goto release_write_pending;
//        }
    
        spin_lock_irqsave(&hidg->write_spinlock, flags);
    
        /* when our function has been disabled by host */
        if (!hidg->req) {
            free_ep_req(hidg->in_ep, req);
            /*
             * TODO
             * Should we fail with error here?
             */
            goto try_again;
        }
    
        req->status   = 0;
        req->zero     = 0;
        req->length   = count;
        req->complete = f_hidg_req_complete;
        req->context  = hidg;
    
        spin_unlock_irqrestore(&hidg->write_spinlock, flags);
        debug("usb_ep_queue hidg->in_ep!\n");
        status = usb_ep_queue(hidg->in_ep, req, GFP_ATOMIC);
        if (status < 0) {
            debug("usb_ep_queue error on int endpoint %zd\n", status);
            goto release_write_pending;
        } else {
            status = count;
        }
    
        return status;
    release_write_pending:
        spin_lock_irqsave(&hidg->write_spinlock, flags);
        hidg->write_pending = 0;
        spin_unlock_irqrestore(&hidg->write_spinlock, flags);
    
        wake_up(&hidg->write_queue);
    
        return status;

}

ssize_t f_hidg_write(struct file *file, const char *buffer,
                size_t count, loff_t *offp)
{
    struct f_hidg *hidg  = file->private_data;
    struct usb_request *req;
    unsigned long flags;
    ssize_t status = -ENOMEM;
    debug("f_hidg_write !\n");
    spin_lock_irqsave(&hidg->write_spinlock, flags);

#define WRITE_COND (!hidg->write_pending)
try_again:
    /* write queue */
    while (!WRITE_COND) {
        spin_unlock_irqrestore(&hidg->write_spinlock, flags);

#if 0
        if (wait_event_interruptible_exclusive(
                hidg->write_queue, WRITE_COND))
            return -ERESTARTSYS;
#endif
        spin_lock_irqsave(&hidg->write_spinlock, flags);
    }

    hidg->write_pending = 1;
    req = hidg->req;
    count  = min_t(unsigned, count, hidg->report_length);

    spin_unlock_irqrestore(&hidg->write_spinlock, flags);
#if 0    
    status = copy_from_user(req->buf, buffer, count);

    if (status != 0) {
        debug("copy_from_user error\n");
        status = -EINVAL;
        goto release_write_pending;
    }
#endif
    HV_MEMCPY(req->buf, buffer, count);

    spin_lock_irqsave(&hidg->write_spinlock, flags);

    /* when our function has been disabled by host */
    if (!hidg->req) {
        free_ep_req(hidg->in_ep, req);
        /*
         * TODO
         * Should we fail with error here?
         */
        goto try_again;
    }

    req->status   = 0;
    req->zero     = 0;
    req->length   = count;
    req->complete = f_hidg_req_complete;
    req->context  = hidg;

    spin_unlock_irqrestore(&hidg->write_spinlock, flags);

    status = usb_ep_queue(hidg->in_ep, req, GFP_ATOMIC);
    if (status < 0) {
        debug("usb_ep_queue error on int endpoint %zd\n", status);
        goto release_write_pending;
    } else {
        status = count;
    }

    return status;
release_write_pending:
    spin_lock_irqsave(&hidg->write_spinlock, flags);
    hidg->write_pending = 0;
    spin_unlock_irqrestore(&hidg->write_spinlock, flags);

    wake_up(&hidg->write_queue);

    return status;
}

#if 0
static __poll_t f_hidg_poll(struct file *file, poll_table *wait)
{
    struct f_hidg    *hidg  = file->private_data;
    __poll_t    ret = 0;

    poll_wait(file, &hidg->read_queue, wait);
    poll_wait(file, &hidg->write_queue, wait);

    if (WRITE_COND)
        ret |= EPOLLOUT | EPOLLWRNORM;

    if (READ_COND)
        ret |= EPOLLIN | EPOLLRDNORM;

    return ret;
}
#endif

#undef WRITE_COND
#undef READ_COND

int f_hidg_release(struct f_hidg *hidg, struct file *fd)
{
    fd->private_data = NULL;
    return 0;
}

int f_hidg_open(struct f_hidg *hidg, struct file *fd)
{
//    struct f_hidg *hidg =
//        container_of(inode->i_cdev, struct f_hidg, cdev);

    fd->private_data = hidg;
    return 0;
}

/*-------------------------------------------------------------------------*/
/*                                usb_function                             */

static inline struct usb_request *hidg_alloc_ep_req(struct usb_ep *ep,
                            unsigned length)
{
    return alloc_ep_req(ep, length);
}

static void hidg_set_report_complete(struct usb_ep *ep, struct usb_request *req)
{
    struct f_hidg *hidg = (struct f_hidg *) req->context;
    struct usb_composite_dev *cdev = hidg->func.config->cdev;
    struct f_hidg_req_list *req_list;
    unsigned long flags;

    switch (req->status) {
    case 0:
        req_list = USB_MALLOC(sizeof(*req_list));
        if (!req_list) {
            debug("Unable to allocate mem for req_list\n");
            goto free_req;
        }
        HV_MEMSET(req_list, 0, sizeof(*req_list));

        req_list->req = req;

        spin_lock_irqsave(&hidg->read_spinlock, flags);
        list_add_tail(&req_list->list, &hidg->completed_out_req);
        spin_unlock_irqrestore(&hidg->read_spinlock, flags);

        wake_up(&hidg->read_queue);
        break;
    default:
        debug("Set report failed %d\n", req->status);
        /* FALLTHROUGH */
    case -ECONNABORTED:        /* hardware forced ep reset */
    case -ECONNRESET:        /* request dequeued */
    case -ESHUTDOWN:        /* disconnect from host */
free_req:
        free_ep_req(ep, req);
        return;
    }
}

static int hidg_setup(struct usb_function *f,
        const struct usb_ctrlrequest *ctrl)
{
    struct f_hidg            *hidg = func_to_hidg(f);
    struct usb_composite_dev    *cdev = f->config->cdev;
    struct usb_request        *req  = cdev->req;
    int status = 0;
    __u16 value, length;

    value    = ctrl->wValue;
    length    = ctrl->wLength;

    debug(
         "%s crtl_request : bRequestType:0x%x bRequest:0x%x Value:0x%x\n",
         __func__, ctrl->bRequestType, ctrl->bRequest, value);

    switch ((ctrl->bRequestType << 8) | ctrl->bRequest) {
    case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
          | HID_REQ_GET_REPORT):
        debug("get_report\n");

        /* send an empty report */
        length = min_t(unsigned, length, hidg->report_length);
        HV_MEMSET(req->buf, 0x0, length);

        goto respond;
        break;

    case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
          | HID_REQ_GET_PROTOCOL):
        debug("get_protocol\n");
        length = min_t(unsigned int, length, 1);
        ((u8 *) req->buf)[0] = hidg->protocol;
        goto respond;
        break;

    case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
          | HID_REQ_SET_REPORT):
        debug("set_report | wLength=%d\n", ctrl->wLength);
        goto stall;
        break;

    case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
          | HID_REQ_SET_PROTOCOL):
        debug("set_protocol\n");
        if (value > HID_REPORT_PROTOCOL)
            goto stall;
        length = 0;
        /*
         * We assume that programs implementing the Boot protocol
         * are also compatible with the Report Protocol
         */
        if (hidg->bInterfaceSubClass == USB_INTERFACE_SUBCLASS_BOOT) {
            hidg->protocol = value;
            goto respond;
        }
        goto stall;
        break;

    case ((USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_INTERFACE) << 8
          | USB_REQ_GET_DESCRIPTOR):
        switch (value >> 8) {
        case HID_DT_HID:
        {
            struct hid_descriptor hidg_desc_copy = hidg_desc;

            debug("USB_REQ_GET_DESCRIPTOR: HID\n");
            hidg_desc_copy.desc[0].bDescriptorType = HID_DT_REPORT;
            hidg_desc_copy.desc[0].wDescriptorLength =
                cpu_to_le16(hidg->report_desc_length);

            length = min_t(unsigned short, length,
                           hidg_desc_copy.bLength);
            HV_MEMCPY(req->buf, &hidg_desc_copy, length);
            goto respond;
            break;
        }
        case HID_DT_REPORT:
            debug("USB_REQ_GET_DESCRIPTOR: REPORT\n");
            length = min_t(unsigned short, length,
                           hidg->report_desc_length);
            HV_MEMCPY(req->buf, hidg->report_desc, length);
            goto respond;
            break;

        default:
            debug("Unknown descriptor request 0x%x\n",
                 value >> 8);
            goto stall;
            break;
        }
        break;

    default:
        debug("Unknown request 0x%x\n",
             ctrl->bRequest);
        goto stall;
        break;
    }

stall:
    return -EOPNOTSUPP;

respond:
    req->zero = 0;
    req->length = length;
    status = usb_ep_queue(cdev->gadget->ep0, req, GFP_ATOMIC);
    if (status < 0)
        debug("usb_ep_queue error on ep0 %d\n", value);
    return status;
}

static void hidg_disable(struct usb_function *f)
{
    struct f_hidg *hidg = func_to_hidg(f);
    struct f_hidg_req_list *list, *next;
    unsigned long flags;

    usb_ep_disable(hidg->in_ep);
    usb_ep_disable(hidg->out_ep);

    spin_lock_irqsave(&hidg->read_spinlock, flags);
    list_for_each_entry_safe(list, next, &hidg->completed_out_req, list) {
        free_ep_req(hidg->out_ep, list->req);
        list_del(&list->list);
        kfree(list);
    }
    spin_unlock_irqrestore(&hidg->read_spinlock, flags);

    spin_lock_irqsave(&hidg->write_spinlock, flags);
    if (!hidg->write_pending) {
        free_ep_req(hidg->in_ep, hidg->req);
        hidg->write_pending = 1;
    }

    hidg->req = NULL;
    spin_unlock_irqrestore(&hidg->write_spinlock, flags);
}

extern struct f_hidg    *global_hidg;

static int hidg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
{
    struct usb_composite_dev        *cdev = f->config->cdev;
    struct f_hidg                *hidg = func_to_hidg(f);
    struct usb_request            *req_in = NULL;
    unsigned long                flags;
    int i, status = 0;

    global_hidg = hidg;
    
    debug("enter hidg_set_alt.\n");
    if (hidg->in_ep != NULL) {
        /* restart endpoint */
        usb_ep_disable(hidg->in_ep);

        status = config_ep_by_speed(f->config->cdev->gadget, f,
                        hidg->in_ep);
        if (status) {
            debug("config_ep_by_speed FAILED!\n");
            goto fail;
        }
        debug("1111111. hidg->report_length is %d\n", hidg->report_length);
        status = usb_ep_enable(hidg->in_ep);
        if (status < 0) {
            debug("Enable IN endpoint FAILED!\n");
            goto fail;
        }
        hidg->in_ep->driver_data = hidg;

        req_in = hidg_alloc_ep_req(hidg->in_ep, hidg->report_length);
        if (!req_in) {
            status = -ENOMEM;
            goto disable_ep_in;
        }
    }


    if (hidg->out_ep != NULL) {
        /* restart endpoint */
        usb_ep_disable(hidg->out_ep);

        status = config_ep_by_speed(f->config->cdev->gadget, f,
                        hidg->out_ep);
        if (status) {
            debug( "config_ep_by_speed FAILED!\n");
            goto free_req_in;
        }
        debug("22222222.\n");
        status = usb_ep_enable(hidg->out_ep);

        if (status < 0) {
            debug( "Enable OUT endpoint FAILED!\n");
            goto free_req_in;
        }
        hidg->out_ep->driver_data = hidg;

        /*
         * allocate a bunch of read buffers and queue them all at once.
         */
        for (i = 0; i < hidg->qlen && status == 0; i++) {
            struct usb_request *req =
                    hidg_alloc_ep_req(hidg->out_ep,
                              hidg->report_length);
            if (req) {
                req->complete = hidg_set_report_complete;
                req->context  = hidg;
                debug("33333333.\n");
                status = usb_ep_queue(hidg->out_ep, req,
                              GFP_ATOMIC);
                if (status) {
                    debug( "%s queue req --> %d\n",
                        hidg->out_ep->name, status);
                    free_ep_req(hidg->out_ep, req);
                }
            } else {
                status = -ENOMEM;
                goto disable_out_ep;
            }
        }
    }

    if (hidg->in_ep != NULL) {
        spin_lock_irqsave(&hidg->write_spinlock, flags);
        hidg->req = req_in;
        hidg->write_pending = 0;
        spin_unlock_irqrestore(&hidg->write_spinlock, flags);
        f_write(hidg, const_buffer, 4, 0);
        wake_up(&hidg->write_queue);
    }
    debug("after hidg_set_alt.\n");
    return 0;
disable_out_ep:
    usb_ep_disable(hidg->out_ep);
free_req_in:
    if (req_in)
        free_ep_req(hidg->in_ep, req_in);

disable_ep_in:
    if (hidg->in_ep)
        usb_ep_disable(hidg->in_ep);

fail:
    return status;
}

#if 0
static const struct file_operations f_hidg_fops = {
    .owner        = THIS_MODULE,
    .open        = f_hidg_open,
    .release    = f_hidg_release,
    .write        = f_hidg_write,
    .read        = f_hidg_read,
    .poll        = f_hidg_poll,
    .llseek        = noop_llseek,
};
#endif

static int hidg_bind(struct usb_configuration *c, struct usb_function *f)
{
    struct usb_ep        *ep_in;
    struct usb_ep        *ep_out;
    struct f_hidg        *hidg = func_to_hidg(f);
    struct usb_string    *us;
    struct device        *device;
    int            status;
    dev_t            dev;

    /* maybe allocate device-global string IDs, and patch descriptors */
    us = usb_gstrings_attach(c->cdev, ct_func_strings,
                 ARRAY_SIZE(ct_func_string_defs));

    debug("*********us string is %s.\n",us->s);
    if (IS_ERR(us))
        return PTR_ERR(us);

    
    hidg_interface_desc.iInterface = us[CT_FUNC_HID_IDX].id;

    /* allocate instance-specific interface IDs, and patch descriptors */
    status = usb_interface_id(c, f);
    if (status < 0)
        goto fail;
    hidg_interface_desc.bInterfaceNumber = status;

    /* allocate instance-specific endpoints */
    status = -ENODEV;
    ep_out = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_out_ep_desc);
    ep_out->desc = &hidg_fs_out_ep_desc;
    if (!ep_out)
        goto fail;
    hidg->out_ep = ep_out;

    ep_in = usb_ep_autoconfig(c->cdev->gadget, &hidg_fs_in_ep_desc);
    ep_in->desc = &hidg_fs_in_ep_desc;

    if (!ep_in)
        goto fail;
    hidg->in_ep = ep_in;

    /* set descriptor dynamic values */
    hidg_interface_desc.bInterfaceSubClass = hidg->bInterfaceSubClass;
    hidg_interface_desc.bInterfaceProtocol = hidg->bInterfaceProtocol;
    hidg->protocol = HID_REPORT_PROTOCOL;
    hidg_ss_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
    hidg_ss_in_comp_desc.wBytesPerInterval =
                cpu_to_le16(hidg->report_length);
    hidg_hs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
    hidg_fs_in_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
    hidg_ss_out_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
    hidg_ss_out_comp_desc.wBytesPerInterval =
                cpu_to_le16(hidg->report_length);
    hidg_hs_out_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
    hidg_fs_out_ep_desc.wMaxPacketSize = cpu_to_le16(hidg->report_length);
    /*
     * We can use hidg_desc struct here but we should not relay
     * that its content won't change after returning from this function.
     */
    hidg_desc.desc[0].bDescriptorType = HID_DT_REPORT;
    hidg_desc.desc[0].wDescriptorLength =
        cpu_to_le16(hidg->report_desc_length);

    hidg_hs_in_ep_desc.bEndpointAddress =
        hidg_fs_in_ep_desc.bEndpointAddress;
    hidg_hs_out_ep_desc.bEndpointAddress =
        hidg_fs_out_ep_desc.bEndpointAddress;

    hidg_ss_in_ep_desc.bEndpointAddress =
        hidg_fs_in_ep_desc.bEndpointAddress;
    hidg_ss_out_ep_desc.bEndpointAddress =
        hidg_fs_out_ep_desc.bEndpointAddress;

    status = usb_assign_descriptors(f, hidg_fs_descriptors,
            hidg_hs_descriptors, hidg_ss_descriptors);
    if (status)
        goto fail;

    spin_lock_init(&hidg->write_spinlock);
    hidg->write_pending = 1;
    hidg->req = NULL;
    spin_lock_init(&hidg->read_spinlock);
    init_waitqueue_head(&hidg->write_queue);
    init_waitqueue_head(&hidg->read_queue);
    INIT_LIST_HEAD(&hidg->completed_out_req);

    /* create char device */
    cdev_init(&hidg->cdev, &f_hidg_fops);
    dev = MKDEV(major, hidg->minor);
    status = cdev_add(&hidg->cdev, dev, 1);
    if (status)
        goto fail_free_descs;

#if 0
    device = device_create(hidg_class, NULL, dev, NULL,
                   "%s%d", "hidg", hidg->minor);
    if (IS_ERR(device)) {
        status = PTR_ERR(device);
        goto del;
    }
#endif

    return 0;
//del:
//    cdev_del(&hidg->cdev);
fail_free_descs:
    usb_free_all_descriptors(f);
fail:
    debug("hidg_bind FAILED\n");
    if (hidg->req != NULL)
        free_ep_req(hidg->in_ep, hidg->req);

    return status;
}

#if 0
static inline int hidg_get_minor(void)
{
    int ret;

    ret = ida_simple_get(&hidg_ida, 0, 0, GFP_KERNEL);
    if (ret >= HIDG_MINORS) {
        ida_simple_remove(&hidg_ida, ret);
        ret = -ENODEV;
    }

    return ret;
}

static inline struct f_hid_opts *to_f_hid_opts(struct config_item *item)
{
    return container_of(to_config_group(item), struct f_hid_opts,
                func_inst.group);
}

static void hid_attr_release(struct config_item *item)
{
    struct f_hid_opts *opts = to_f_hid_opts(item);

    usb_put_function_instance(&opts->func_inst);
}


static struct configfs_item_operations hidg_item_ops = {
    .release    = hid_attr_release,
};


#define F_HID_OPT(name, prec, limit)                    \
static ssize_t f_hid_opts_##name##_show(struct config_item *item, char *page)\
{                                    \
    struct f_hid_opts *opts = to_f_hid_opts(item);            \
    int result;                            \
                                    \
    mutex_lock(&opts->lock);                    \
    result = sprintf(page, "%d\n", opts->name);            \
    mutex_unlock(&opts->lock);                    \
                                    \
    return result;                            \
}                                    \
                                    \
static ssize_t f_hid_opts_##name##_store(struct config_item *item,    \
                     const char *page, size_t len)    \
{                                    \
    struct f_hid_opts *opts = to_f_hid_opts(item);            \
    int ret;                            \
    u##prec num;                            \
                                    \
    mutex_lock(&opts->lock);                    \
    if (opts->refcnt) {                        \
        ret = -EBUSY;                        \
        goto end;                        \
    }                                \
                                    \
    ret = kstrtou##prec(page, 0, &num);                \
    if (ret)                            \
        goto end;                        \
                                    \
    if (num > limit) {                        \
        ret = -EINVAL;                        \
        goto end;                        \
    }                                \
    opts->name = num;                        \
    ret = len;                            \
                                    \
end:                                    \
    mutex_unlock(&opts->lock);                    \
    return ret;                            \
}                                    \
                                    \
CONFIGFS_ATTR(f_hid_opts_, name)

F_HID_OPT(subclass, 8, 255);
F_HID_OPT(protocol, 8, 255);
F_HID_OPT(report_length, 16, 65535);



static ssize_t f_hid_opts_report_desc_show(struct config_item *item, char *page)
{
    struct f_hid_opts *opts = to_f_hid_opts(item);
    int result;

    mutex_lock(&opts->lock);
    result = opts->report_desc_length;
    HV_MEMCPY(page, opts->report_desc, opts->report_desc_length);
    mutex_unlock(&opts->lock);

    return result;
}

static ssize_t f_hid_opts_report_desc_store(struct config_item *item,
                        const char *page, size_t len)
{
    struct f_hid_opts *opts = to_f_hid_opts(item);
    int ret = -EBUSY;
    char *d;

    mutex_lock(&opts->lock);

    if (opts->refcnt)
        goto end;
    if (len > PAGE_SIZE) {
        ret = -ENOSPC;
        goto end;
    }
    d = kmemdup(page, len, GFP_KERNEL);
    if (!d) {
        ret = -ENOMEM;
        goto end;
    }
    kfree(opts->report_desc);
    opts->report_desc = d;
    opts->report_desc_length = len;
    opts->report_desc_alloc = true;
    ret = len;
end:
    mutex_unlock(&opts->lock);
    return ret;
}


static ssize_t f_hid_opts_dev_show(struct config_item *item, char *page)
{
    struct f_hid_opts *opts = to_f_hid_opts(item);

    return sprintf(page, "%d:%d\n", major, opts->minor);
}


static struct configfs_attribute *hid_attrs[] = {
    &f_hid_opts_attr_subclass,
    &f_hid_opts_attr_protocol,
    &f_hid_opts_attr_report_length,
    &f_hid_opts_attr_report_desc,
    &f_hid_opts_attr_dev,
    NULL,
};

static const struct config_item_type hid_func_type = {
    .ct_item_ops    = &hidg_item_ops,
    .ct_attrs    = hid_attrs,
    .ct_owner    = THIS_MODULE,
};


static inline void hidg_put_minor(int minor)
{
    ida_simple_remove(&hidg_ida, minor);
}
#endif

static void hidg_free_inst(struct usb_function_instance *f)
{
    struct f_hid_opts *opts;

    opts = container_of(f, struct f_hid_opts, func_inst);
#if 0
    mutex_lock(&hidg_ida_lock);
    hidg_put_minor(opts->minor);
    if (ida_is_empty(&hidg_ida))
        ghid_cleanup();
    mutex_unlock(&hidg_ida_lock);
#endif
    if (opts->report_desc_alloc)
        kfree(opts->report_desc);

    kfree(opts);
}

static struct usb_function_instance *hidg_alloc_inst(void)
{
    struct f_hid_opts *opts;
    struct usb_function_instance *ret;
    int status = 0;

    opts = USB_MALLOC(sizeof(*opts));
    if (!opts)
        return ERR_PTR(-ENOMEM);
    HV_MEMSET(opts, 0, sizeof(*opts));
    mutex_init(&opts->lock);
    opts->func_inst.free_func_inst = hidg_free_inst;
    ret = &opts->func_inst;
#if 0
    mutex_lock(&hidg_ida_lock);

    if (ida_is_empty(&hidg_ida)) {
        status = ghid_setup(NULL, HIDG_MINORS);
        if (status)  {
            ret = ERR_PTR(status);
            kfree(opts);
            goto unlock;
        }
    }

    opts->minor = hidg_get_minor();
    if (opts->minor < 0) {
        ret = ERR_PTR(opts->minor);
        kfree(opts);

        if (ida_is_empty(&hidg_ida))
            ghid_cleanup();

        goto unlock;

    }
#endif    
//    config_group_init_type_name(&opts->func_inst.group, "", &hid_func_type);

//unlock:
//    mutex_unlock(&hidg_ida_lock);
    return ret;
}

static void hidg_free(struct usb_function *f)
{
    struct f_hidg *hidg;
    struct f_hid_opts *opts;

    hidg = func_to_hidg(f);
    opts = container_of(f->fi, struct f_hid_opts, func_inst);
    kfree(hidg->report_desc);
    kfree(hidg);
    mutex_lock(&opts->lock);
    --opts->refcnt;
    mutex_unlock(&opts->lock);
}

static void hidg_unbind(struct usb_configuration *c, struct usb_function *f)
{
    struct f_hidg *hidg = func_to_hidg(f);

    //device_destroy(hidg_class, MKDEV(major, hidg->minor));
    cdev_del(&hidg->cdev);

    usb_free_all_descriptors(f);
}


static struct usb_function *hidg_alloc(struct usb_function_instance *fi)
{
    struct f_hidg *hidg;
    struct f_hid_opts *opts;

    debug("enter hidg_alloc.size is %d\n",sizeof(*hidg));
    /* allocate and initialize one new instance */
    hidg = USB_MALLOC(sizeof(*hidg));
    if (!hidg)
        return ERR_PTR(-ENOMEM);
    HV_MEMSET(hidg, 0, sizeof(*hidg));

    opts = container_of(fi, struct f_hid_opts, func_inst);

    mutex_lock(&opts->lock);
    ++opts->refcnt;

    hidg->minor = opts->minor;
    hidg->bInterfaceSubClass = opts->subclass;
    hidg->bInterfaceProtocol = opts->protocol;
    hidg->report_length = opts->report_length;
    hidg->report_desc_length = opts->report_desc_length;
    debug("hidg->report_desc_length is 0x%x,opts->report_desc is 0x%08x.\n",hidg->report_desc_length,opts->report_desc);
    if (opts->report_desc && hidg->report_desc_length) {      //lxn add
        hidg->report_desc = kmemdup(opts->report_desc,
                        opts->report_desc_length);
        debug("hidg->report_desc is 0x%08x.\n",hidg->report_desc);
        if (!hidg->report_desc) {
            kfree(hidg);
            mutex_unlock(&opts->lock);
            return ERR_PTR(-ENOMEM);
        }
    }

    debug("hidg_alloc:after kmemdup.\n");
    mutex_unlock(&opts->lock);

    hidg->func.name    = "hid";
    hidg->func.bind    = hidg_bind;
    hidg->func.unbind  = hidg_unbind;
    hidg->func.set_alt = hidg_set_alt;
    hidg->func.disable = hidg_disable;
    hidg->func.setup   = hidg_setup;
    hidg->func.free_func = hidg_free;

    /* this could me made configurable at some point */
    hidg->qlen       = 4;
    debug("last hidg_alloc.\n");
    return &hidg->func;
}


int ghid_setup(struct usb_gadget *g, int count)
{
    int status;
    dev_t dev;

    hidg_class = class_create(THIS_MODULE, "hidg");
    if (IS_ERR(hidg_class)) {
        status = PTR_ERR(hidg_class);
        hidg_class = NULL;
        return status;
    }

    status = alloc_chrdev_region(&dev, 0, count, "hidg");
    if (status) {
        class_destroy(hidg_class);
        hidg_class = NULL;
        return status;
    }

    major = MAJOR(dev);
    minors = count;

    return 0;
}

void ghid_cleanup(void)
{
    if (major) {
        unregister_chrdev_region(MKDEV(major, 0), minors);
        major = minors = 0;
    }

    class_destroy(hidg_class);
    hidg_class = NULL;
}


static struct usb_function_driver hidusb_func = {    
    
    .name = "hid",
    .mod  = THIS_MODULE,
    .alloc_inst = hidg_alloc_inst,
    .alloc_func = hidg_alloc,

};    


int hid_modinit(void)
{
    int ret = 0;
    ret = usb_function_register(&hidusb_func);
    return ret;
}


