/*
 * Xilinx USB peripheral controller driver
 *
 * Copyright (C) 2004 by Thomas Rathbone
 * Copyright (C) 2005 by HP Labs
 * Copyright (C) 2005 by David Brownell
 * Copyright (C) 2010 - 2014 Xilinx, Inc.
 *
 * Some parts of this driver code is based on the driver for at91-series
 * USB peripheral controller (at91_udc.c).
 *
 * This program is free software; you can redistribute it
 * and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation;
 * either version 2 of the License, or (at your option) any
 * later version.
 */

#include <linux/delay.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
#include <linux/of_irq.h>
#include <linux/prefetch.h>
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>

/* Register offsets for the USB device.*/
#define XUSB_EP0_CONFIG_OFFSET          0x0000  /* EP0 Config Reg Offset */
#define XUSB_SETUP_PKT_ADDR_OFFSET      0x0080  /* Setup Packet Address */
#define XUSB_ADDRESS_OFFSET             0x0100  /* Address Register */
#define XUSB_CONTROL_OFFSET             0x0104  /* Control Register */
#define XUSB_STATUS_OFFSET              0x0108  /* Status Register */
#define XUSB_FRAMENUM_OFFSET            0x010C  /* Frame Number Register */
#define XUSB_IER_OFFSET                 0x0110  /* Interrupt Enable Register */
#define XUSB_BUFFREADY_OFFSET           0x0114  /* Buffer Ready Register */
#define XUSB_TESTMODE_OFFSET            0x0118  /* Test Mode Register */
#define XUSB_DMA_RESET_OFFSET           0x0200  /* DMA Soft Reset Register */
#define XUSB_DMA_CONTROL_OFFSET         0x0204  /* DMA Control Register */
#define XUSB_DMA_DSAR_ADDR_OFFSET       0x0208  /* DMA source Address Reg */
#define XUSB_DMA_DDAR_ADDR_OFFSET       0x020C  /* DMA destination Addr Reg */
#define XUSB_DMA_LENGTH_OFFSET          0x0210  /* DMA Length Register */
#define XUSB_DMA_STATUS_OFFSET          0x0214  /* DMA Status Register */

/* Endpoint Configuration Space offsets */
#define XUSB_EP_CFGSTATUS_OFFSET        0x00    /* Endpoint Config Status  */
#define XUSB_EP_BUF0COUNT_OFFSET        0x08    /* Buffer 0 Count */
#define XUSB_EP_BUF1COUNT_OFFSET        0x0C    /* Buffer 1 Count */

#define XUSB_CONTROL_USB_READY_MASK     0x80000000 /* USB ready Mask */
#define XUSB_CONTROL_USB_RMTWAKE_MASK   0x40000000 /* Remote wake up mask */

/* Interrupt register related masks.*/
#define XUSB_STATUS_GLOBAL_INTR_MASK    0x80000000 /* Global Intr Enable */
#define XUSB_STATUS_DMADONE_MASK        0x04000000 /* DMA done Mask */
#define XUSB_STATUS_DMAERR_MASK         0x02000000 /* DMA Error Mask */
#define XUSB_STATUS_DMABUSY_MASK        0x80000000 /* DMA Error Mask */
#define XUSB_STATUS_RESUME_MASK         0x01000000 /* USB Resume Mask */
#define XUSB_STATUS_RESET_MASK          0x00800000 /* USB Reset Mask */
#define XUSB_STATUS_SUSPEND_MASK        0x00400000 /* USB Suspend Mask */
#define XUSB_STATUS_DISCONNECT_MASK     0x00200000 /* USB Disconnect Mask */
#define XUSB_STATUS_FIFO_BUFF_RDY_MASK  0x00100000 /* FIFO Buff Ready Mask */
#define XUSB_STATUS_FIFO_BUFF_FREE_MASK 0x00080000 /* FIFO Buff Free Mask */
#define XUSB_STATUS_SETUP_PACKET_MASK   0x00040000 /* Setup packet received */
#define XUSB_STATUS_EP1_BUFF2_COMP_MASK 0x00000200 /* EP 1 Buff 2 Processed */
#define XUSB_STATUS_EP1_BUFF1_COMP_MASK 0x00000002 /* EP 1 Buff 1 Processed */
#define XUSB_STATUS_EP0_BUFF2_COMP_MASK 0x00000100 /* EP 0 Buff 2 Processed */
#define XUSB_STATUS_EP0_BUFF1_COMP_MASK 0x00000001 /* EP 0 Buff 1 Processed */
#define XUSB_STATUS_HIGH_SPEED_MASK     0x00010000 /* USB Speed Mask */
/* Suspend,Reset,Suspend and Disconnect Mask */
#define XUSB_STATUS_INTR_EVENT_MASK     0x01E00000
/* Buffers  completion Mask */
#define XUSB_STATUS_INTR_BUFF_COMP_ALL_MASK     0x0000FEFF
/* Mask for buffer 0 and buffer 1 completion for all Endpoints */
#define XUSB_STATUS_INTR_BUFF_COMP_SHIFT_MASK   0x00000101
#define XUSB_STATUS_EP_BUFF2_SHIFT      8          /* EP buffer offset */

/* Endpoint Configuration Status Register */
#define XUSB_EP_CFG_VALID_MASK          0x80000000 /* Endpoint Valid bit */
#define XUSB_EP_CFG_STALL_MASK          0x40000000 /* Endpoint Stall bit */
#define XUSB_EP_CFG_DATA_TOGGLE_MASK    0x08000000 /* Endpoint Data toggle */

/* USB device specific global configuration constants.*/
#define XUSB_MAX_ENDPOINTS              8       /* Maximum End Points */
#define XUSB_EP_NUMBER_ZERO             0       /* End point Zero */
/* DPRAM is the source address for DMA transfer */
#define XUSB_DMA_READ_FROM_DPRAM        0x80000000
#define XUSB_DMA_DMASR_BUSY             0x80000000 /* DMA busy */
#define XUSB_DMA_DMASR_ERROR            0x40000000 /* DMA Error */
/*
 * When this bit is set, the DMA buffer ready bit is set by hardware upon
 * DMA transfer completion.
 */
#define XUSB_DMA_BRR_CTRL               0x40000000 /* DMA bufready ctrl bit */
/* Phase States */
#define SETUP_PHASE                     0x0000  /* Setup Phase */
#define DATA_PHASE                      0x0001  /* Data Phase */
#define STATUS_PHASE                    0x0002  /* Status Phase */

#define EP0_MAX_PACKET          64 /* Endpoint 0 maximum packet length */
#define STATUSBUFF_SIZE         2  /* Buffer size for GET_STATUS command */
#define EPNAME_SIZE             4  /* Buffer size for endpoint name */

/* container_of helper macros */
#define to_udc(g)        container_of((g), struct xusb_udc, gadget)
#define to_xusb_ep(ep)   container_of((ep), struct xusb_ep, ep_usb)
#define to_xusb_req(req) container_of((req), struct xusb_req, usb_req)

/**
 * struct xusb_req - Xilinx USB device request structure
 * @usb_req: Linux usb request structure
 * @queue: usb device request queue
 * @ep: pointer to xusb_endpoint structure
 */
struct xusb_req {
        struct usb_request usb_req;
        struct list_head queue;
        struct xusb_ep *ep;
};

/**
 * struct xusb_ep - USB end point structure.
 * @ep_usb: usb endpoint instance
 * @queue: endpoint message queue
 * @udc: xilinx usb peripheral driver instance pointer
 * @desc: pointer to the usb endpoint descriptor
 * @rambase: the endpoint buffer address
 * @offset: the endpoint register offset value
 * @name: name of the endpoint
 * @epnumber: endpoint number
 * @maxpacket: maximum packet size the endpoint can store
 * @buffer0count: the size of the packet recieved in the first buffer
 * @buffer1count: the size of the packet received in the second buffer
 * @curbufnum: current buffer of endpoint that will be processed next
 * @buffer0ready: the busy state of first buffer
 * @buffer1ready: the busy state of second buffer
 * @is_in: endpoint direction (IN or OUT)
 * @is_iso: endpoint type(isochronous or non isochronous)
 */
struct xusb_ep {
        struct usb_ep ep_usb;
        struct list_head queue;
        struct xusb_udc *udc;
        const struct usb_endpoint_descriptor *desc;
        u32  rambase;
        u32  offset;
        char name[4];
        u16  epnumber;
        u16  maxpacket;
        u16  buffer0count;
        u16  buffer1count;
        u8   curbufnum;
        bool buffer0ready;
        bool buffer1ready;
        bool is_in;
        bool is_iso;
};

/**
 * struct xusb_udc -  USB peripheral driver structure
 * @gadget: USB gadget driver instance
 * @ep: an array of endpoint structures
 * @driver: pointer to the usb gadget driver instance
 * @setup: usb_ctrlrequest structure for control requests
 * @req: pointer to dummy request for get status command
 * @dev: pointer to device structure in gadget
 * @usb_state: device in suspended state or not
 * @remote_wkp: remote wakeup enabled by host
 * @setupseqtx: tx status
 * @setupseqrx: rx status
 * @addr: the usb device base address
 * @lock: instance of spinlock
 * @dma_enabled: flag indicating whether the dma is included in the system
 * @read_fn: function pointer to read device registers
 * @write_fn: function pointer to write to device registers
 */
struct xusb_udc {
        struct usb_gadget gadget;
        struct xusb_ep ep[8];
        struct usb_gadget_driver *driver;
        struct usb_ctrlrequest setup;
        struct xusb_req *req;
        struct device *dev;
        u32 usb_state;
        u32 remote_wkp;
        u32 setupseqtx;
        u32 setupseqrx;
        void __iomem *addr;
        spinlock_t lock;
        bool dma_enabled;

        unsigned int (*read_fn)(void __iomem *);
        void (*write_fn)(void __iomem *, u32, u32);
};

/* Endpoint buffer start addresses in the core */
static u32 rambase[8] = { 0x22, 0x1000, 0x1100, 0x1200, 0x1300, 0x1400, 0x1500,
                          0x1600 };

static const char driver_name[] = "xilinx-udc";
static const char ep0name[] = "ep0";

/* Control endpoint configuration.*/
static const struct usb_endpoint_descriptor config_bulk_out_desc = {
        .bLength                = USB_DT_ENDPOINT_SIZE,
        .bDescriptorType        = USB_DT_ENDPOINT,
        .bEndpointAddress       = USB_DIR_OUT,
        .bmAttributes           = USB_ENDPOINT_XFER_BULK,
        .wMaxPacketSize         = cpu_to_le16(EP0_MAX_PACKET),
};

/**
 * xudc_write32 - little endian write to device registers
 * @addr: base addr of device registers
 * @offset: register offset
 * @val: data to be written
 */
static void xudc_write32(void __iomem *addr, u32 offset, u32 val)
{
        iowrite32(val, addr + offset);
}

/**
 * xudc_read32 - little endian read from device registers
 * @addr: addr of device register
 * Return: value at addr
 */
static unsigned int xudc_read32(void __iomem *addr)
{
        return ioread32(addr);
}

/**
 * xudc_write32_be - big endian write to device registers
 * @addr: base addr of device registers
 * @offset: register offset
 * @val: data to be written
 */
static void xudc_write32_be(void __iomem *addr, u32 offset, u32 val)
{
        iowrite32be(val, addr + offset);
}

/**
 * xudc_read32_be - big endian read from device registers
 * @addr: addr of device register
 * Return: value at addr
 */
static unsigned int xudc_read32_be(void __iomem *addr)
{
        return ioread32be(addr);
}

/**
 * xudc_wrstatus - Sets up the usb device status stages.
 * @udc: pointer to the usb device controller structure.
 */
static void xudc_wrstatus(struct xusb_udc *udc)
{
        struct xusb_ep *ep0 = &udc->ep[XUSB_EP_NUMBER_ZERO];
        u32 epcfgreg;

        epcfgreg = udc->read_fn(udc->addr + ep0->offset)|
                                XUSB_EP_CFG_DATA_TOGGLE_MASK;
        udc->write_fn(udc->addr, ep0->offset, epcfgreg);
        udc->write_fn(udc->addr, ep0->offset + XUSB_EP_BUF0COUNT_OFFSET, 0);
        udc->write_fn(udc->addr, XUSB_BUFFREADY_OFFSET, 1);
}

/**
 * xudc_epconfig - Configures the given endpoint.
 * @ep: pointer to the usb device endpoint structure.
 * @udc: pointer to the usb peripheral controller structure.
 *
 * This function configures a specific endpoint with the given configuration
 * data.
 */
static void xudc_epconfig(struct xusb_ep *ep, struct xusb_udc *udc)
{
        u32 epcfgreg;

        /*
         * Configure the end point direction, type, Max Packet Size and the
         * EP buffer location.
         */
        epcfgreg = ((ep->is_in << 29) | (ep->is_iso << 28) |
                   (ep->ep_usb.maxpacket << 15) | (ep->rambase));
        udc->write_fn(udc->addr, ep->offset, epcfgreg);

        /* Set the Buffer count and the Buffer ready bits.*/
        udc->write_fn(udc->addr, ep->offset + XUSB_EP_BUF0COUNT_OFFSET,
                      ep->buffer0count);
        udc->write_fn(udc->addr, ep->offset + XUSB_EP_BUF1COUNT_OFFSET,
                      ep->buffer1count);
        if (ep->buffer0ready)
                udc->write_fn(udc->addr, XUSB_BUFFREADY_OFFSET,
                              1 << ep->epnumber);
        if (ep->buffer1ready)
                udc->write_fn(udc->addr, XUSB_BUFFREADY_OFFSET,
                              1 << (ep->epnumber + XUSB_STATUS_EP_BUFF2_SHIFT));
}

/**
 * xudc_start_dma - Starts DMA transfer.
 * @ep: pointer to the usb device endpoint structure.
 * @src: DMA source address.
 * @dst: DMA destination address.
 * @length: number of bytes to transfer.
 *
 * Return: 0 on success, error code on failure
 *
 * This function starts DMA transfer by writing to DMA source,
 * destination and lenth registers.
 */
static int xudc_start_dma(struct xusb_ep *ep, dma_addr_t src,
                          dma_addr_t dst, u32 length)
{
        struct xusb_udc *udc = ep->udc;
        int rc = 0;
        u32 timeout = 500;
        u32 reg;

        /*
         * Set the addresses in the DMA source and
         * destination registers and then set the length
         * into the DMA length register.
         */
        udc->write_fn(udc->addr, XUSB_DMA_DSAR_ADDR_OFFSET, src);
        udc->write_fn(udc->addr, XUSB_DMA_DDAR_ADDR_OFFSET, dst);
        udc->write_fn(udc->addr, XUSB_DMA_LENGTH_OFFSET, length);

        /*
         * Wait till DMA transaction is complete and
         * check whether the DMA transaction was
         * successful.
         */
        do {
                reg = udc->read_fn(udc->addr + XUSB_DMA_STATUS_OFFSET);
                if (!(reg &  XUSB_DMA_DMASR_BUSY))
                        break;

                /*
                 * We can't sleep here, because it's also called from
                 * interrupt context.
                 */
                timeout--;
                if (!timeout) {
                        dev_err(udc->dev, "DMA timeout\n");
                        return -ETIMEDOUT;
                }
                udelay(1);
        } while (1);

        if ((udc->read_fn(udc->addr + XUSB_DMA_STATUS_OFFSET) &
                          XUSB_DMA_DMASR_ERROR) == XUSB_DMA_DMASR_ERROR){
                dev_err(udc->dev, "DMA Error\n");
                rc = -EINVAL;
        }

        return rc;
}

/**
 * xudc_dma_send - Sends IN data using DMA.
 * @ep: pointer to the usb device endpoint structure.
 * @req: pointer to the usb request structure.
 * @buffer: pointer to data to be sent.
 * @length: number of bytes to send.
 *
 * Return: 0 on success, -EAGAIN if no buffer is free and error
 *         code on failure.
 *
 * This function sends data using DMA.
 */
static int xudc_dma_send(struct xusb_ep *ep, struct xusb_req *req,
                         u8 *buffer, u32 length)
{
        u32 *eprambase;
        dma_addr_t src;
        dma_addr_t dst;
        struct xusb_udc *udc = ep->udc;

        src = req->usb_req.dma + req->usb_req.actual;
        if (req->usb_req.length)
                dma_sync_single_for_device(udc->dev, src,
                                           length, DMA_TO_DEVICE);
        if (!ep->curbufnum && !ep->buffer0ready) {
                /* Get the Buffer address and copy the transmit data.*/
                eprambase = (u32 __force *)(udc->addr + ep->rambase);
                dst = virt_to_phys(eprambase);
                udc->write_fn(udc->addr, ep->offset +
                              XUSB_EP_BUF0COUNT_OFFSET, length);
                udc->write_fn(udc->addr, XUSB_DMA_CONTROL_OFFSET,
                              XUSB_DMA_BRR_CTRL | (1 << ep->epnumber));
                ep->buffer0ready = 1;
                ep->curbufnum = 1;
        } else if (ep->curbufnum && !ep->buffer1ready) {
                /* Get the Buffer address and copy the transmit data.*/
                eprambase = (u32 __force *)(udc->addr + ep->rambase +
                             ep->ep_usb.maxpacket);
                dst = virt_to_phys(eprambase);
                udc->write_fn(udc->addr, ep->offset +
                              XUSB_EP_BUF1COUNT_OFFSET, length);
                udc->write_fn(udc->addr, XUSB_DMA_CONTROL_OFFSET,
                              XUSB_DMA_BRR_CTRL | (1 << (ep->epnumber +
                              XUSB_STATUS_EP_BUFF2_SHIFT)));
                ep->buffer1ready = 1;
                ep->curbufnum = 0;
        } else {
                /* None of ping pong buffers are ready currently .*/
                return -EAGAIN;
        }

        return xudc_start_dma(ep, src, dst, length);
}

/**
 * xudc_dma_receive - Receives OUT data using DMA.
 * @ep: pointer to the usb device endpoint structure.
 * @req: pointer to the usb request structure.
 * @buffer: pointer to storage buffer of received data.
 * @length: number of bytes to receive.
 *
 * Return: 0 on success, -EAGAIN if no buffer is free and error
 *         code on failure.
 *
 * This function receives data using DMA.
 */
static int xudc_dma_receive(struct xusb_ep *ep, struct xusb_req *req,
                            u8 *buffer, u32 length)
{
        u32 *eprambase;
        dma_addr_t src;
        dma_addr_t dst;
        struct xusb_udc *udc = ep->udc;

        dst = req->usb_req.dma + req->usb_req.actual;
        if (!ep->curbufnum && !ep->buffer0ready) {
                /* Get the Buffer address and copy the transmit data */
                eprambase = (u32 __force *)(udc->addr + ep->rambase);
                src = virt_to_phys(eprambase);
                udc->write_fn(udc->addr, XUSB_DMA_CONTROL_OFFSET,
                              XUSB_DMA_BRR_CTRL | XUSB_DMA_READ_FROM_DPRAM |
                              (1 << ep->epnumber));
                ep->buffer0ready = 1;
                ep->curbufnum = 1;
        } else if (ep->curbufnum && !ep->buffer1ready) {
                /* Get the Buffer address and copy the transmit data */
                eprambase = (u32 __force *)(udc->addr +
                             ep->rambase + ep->ep_usb.maxpacket);
                src = virt_to_phys(eprambase);
                udc->write_fn(udc->addr, XUSB_DMA_CONTROL_OFFSET,
                              XUSB_DMA_BRR_CTRL | XUSB_DMA_READ_FROM_DPRAM |
                              (1 << (ep->epnumber +
                              XUSB_STATUS_EP_BUFF2_SHIFT)));
                ep->buffer1ready = 1;
                ep->curbufnum = 0;
        } else {
                /* None of the ping-pong buffers are ready currently */
                return -EAGAIN;
        }

        return xudc_start_dma(ep, src, dst, length);
}

/**
 * xudc_eptxrx - Transmits or receives data to or from an endpoint.
 * @ep: pointer to the usb endpoint configuration structure.
 * @req: pointer to the usb request structure.
 * @bufferptr: pointer to buffer containing the data to be sent.
 * @bufferlen: The number of data bytes to be sent.
 *
 * Return: 0 on success, -EAGAIN if no buffer is free.
 *
 * This function copies the transmit/receive data to/from the end point buffer
 * and enables the buffer for transmission/reception.
 */
static int xudc_eptxrx(struct xusb_ep *ep, struct xusb_req *req,
                       u8 *bufferptr, u32 bufferlen)
{
        u32 *eprambase;
        u32 bytestosend;
        int rc = 0;
        struct xusb_udc *udc = ep->udc;

        bytestosend = bufferlen;
        if (udc->dma_enabled) {
                if (ep->is_in)
                        rc = xudc_dma_send(ep, req, bufferptr, bufferlen);
                else
                        rc = xudc_dma_receive(ep, req, bufferptr, bufferlen);
                return rc;
        }
        /* Put the transmit buffer into the correct ping-pong buffer.*/
        if (!ep->curbufnum && !ep->buffer0ready) {
                /* Get the Buffer address and copy the transmit data.*/
                eprambase = (u32 __force *)(udc->addr + ep->rambase);
                if (ep->is_in) {
                        memcpy(eprambase, bufferptr, bytestosend);
                        udc->write_fn(udc->addr, ep->offset +
                                      XUSB_EP_BUF0COUNT_OFFSET, bufferlen);
                } else {
                        memcpy(bufferptr, eprambase, bytestosend);
                }
                /*
                 * Enable the buffer for transmission.
                 */
                udc->write_fn(udc->addr, XUSB_BUFFREADY_OFFSET,
                              1 << ep->epnumber);
                ep->buffer0ready = 1;
                ep->curbufnum = 1;
        } else if (ep->curbufnum && !ep->buffer1ready) {
                /* Get the Buffer address and copy the transmit data.*/
                eprambase = (u32 __force *)(udc->addr + ep->rambase +
                             ep->ep_usb.maxpacket);
                if (ep->is_in) {
                        memcpy(eprambase, bufferptr, bytestosend);
                        udc->write_fn(udc->addr, ep->offset +
                                      XUSB_EP_BUF1COUNT_OFFSET, bufferlen);
                } else {
                        memcpy(bufferptr, eprambase, bytestosend);
                }
                /*
                 * Enable the buffer for transmission.
                 */
                udc->write_fn(udc->addr, XUSB_BUFFREADY_OFFSET,
                              1 << (ep->epnumber + XUSB_STATUS_EP_BUFF2_SHIFT));
                ep->buffer1ready = 1;
                ep->curbufnum = 0;
        } else {
                /* None of the ping-pong buffers are ready currently */
                return -EAGAIN;
        }
        return rc;
}

/**
 * xudc_done - Exeutes the endpoint data transfer completion tasks.
 * @ep: pointer to the usb device endpoint structure.
 * @req: pointer to the usb request structure.
 * @status: Status of the data transfer.
 *
 * Deletes the message from the queue and updates data transfer completion
 * status.
 */
static void xudc_done(struct xusb_ep *ep, struct xusb_req *req, int status)
{
        struct xusb_udc *udc = ep->udc;

        list_del_init(&req->queue);

        if (req->usb_req.status == -EINPROGRESS)
                req->usb_req.status = status;
        else
                status = req->usb_req.status;

        if (status && status != -ESHUTDOWN)
                dev_dbg(udc->dev, "%s done %p, status %d\n",
                        ep->ep_usb.name, req, status);
        /* unmap request if DMA is present*/
        if (udc->dma_enabled && ep->epnumber && req->usb_req.length)
                usb_gadget_unmap_request(&udc->gadget, &req->usb_req,
                                         ep->is_in);

        if (req->usb_req.complete) {
                spin_unlock(&udc->lock);
                req->usb_req.complete(&ep->ep_usb, &req->usb_req);
                spin_lock(&udc->lock);
        }
}

/**
 * xudc_read_fifo - Reads the data from the given endpoint buffer.
 * @ep: pointer to the usb device endpoint structure.
 * @req: pointer to the usb request structure.
 *
 * Return: 0 if request is completed and -EAGAIN if not completed.
 *
 * Pulls OUT packet data from the endpoint buffer.
 */
static int xudc_read_fifo(struct xusb_ep *ep, struct xusb_req *req)
{
        u8 *buf;
        u32 is_short, count, bufferspace;
        u8 bufoffset;
        u8 two_pkts = 0;
        int ret;
        int retval = -EAGAIN;
        struct xusb_udc *udc = ep->udc;

        if (ep->buffer0ready && ep->buffer1ready) {
                dev_dbg(udc->dev, "Packet NOT ready!\n");
                return retval;
        }
top:
        if (ep->curbufnum)
                bufoffset = XUSB_EP_BUF1COUNT_OFFSET;
        else
                bufoffset = XUSB_EP_BUF0COUNT_OFFSET;

        count = udc->read_fn(udc->addr + ep->offset + bufoffset);

        if (!ep->buffer0ready && !ep->buffer1ready)
                two_pkts = 1;

        buf = req->usb_req.buf + req->usb_req.actual;
        prefetchw(buf);
        bufferspace = req->usb_req.length - req->usb_req.actual;
        is_short = count < ep->ep_usb.maxpacket;

        if (unlikely(!bufferspace)) {
                /*
                 * This happens when the driver's buffer
                 * is smaller than what the host sent.
                 * discard the extra data.
                 */
                if (req->usb_req.status != -EOVERFLOW)
                        dev_dbg(udc->dev, "%s overflow %d\n",
                                ep->ep_usb.name, count);
                req->usb_req.status = -EOVERFLOW;
                xudc_done(ep, req, -EOVERFLOW);
                return 0;
        }

        ret = xudc_eptxrx(ep, req, buf, count);
        switch (ret) {
        case 0:
                req->usb_req.actual += min(count, bufferspace);
                dev_dbg(udc->dev, "read %s, %d bytes%s req %p %d/%d\n",
                        ep->ep_usb.name, count, is_short ? "/S" : "", req,
                        req->usb_req.actual, req->usb_req.length);
                bufferspace -= count;
                /* Completion */
                if ((req->usb_req.actual == req->usb_req.length) || is_short) {
                        if (udc->dma_enabled && req->usb_req.length)
                                dma_sync_single_for_cpu(udc->dev,
                                                        req->usb_req.dma,
                                                        req->usb_req.actual,
                                                        DMA_FROM_DEVICE);
                        xudc_done(ep, req, 0);
                        return 0;
                }
                if (two_pkts) {
                        two_pkts = 0;
                        goto top;
                }
                break;
        case -EAGAIN:
                dev_dbg(udc->dev, "receive busy\n");
                break;
        case -EINVAL:
        case -ETIMEDOUT:
                /* DMA error, dequeue the request */
                xudc_done(ep, req, -ECONNRESET);
                retval = 0;
                break;
        }

        return retval;
}

/**
 * xudc_write_fifo - Writes data into the given endpoint buffer.
 * @ep: pointer to the usb device endpoint structure.
 * @req: pointer to the usb request structure.
 *
 * Return: 0 if request is completed and -EAGAIN if not completed.
 *
 * Loads endpoint buffer for an IN packet.
 */
static int xudc_write_fifo(struct xusb_ep *ep, struct xusb_req *req)
{
        u32 max;
        u32 length;
        int ret;
        int retval = -EAGAIN;
        struct xusb_udc *udc = ep->udc;
        int is_last, is_short = 0;
        u8 *buf;

        max = le16_to_cpu(ep->desc->wMaxPacketSize);
        buf = req->usb_req.buf + req->usb_req.actual;
        prefetch(buf);
        length = req->usb_req.length - req->usb_req.actual;
        length = min(length, max);

        ret = xudc_eptxrx(ep, req, buf, length);
        switch (ret) {
        case 0:
                req->usb_req.actual += length;
                if (unlikely(length != max)) {
                        is_last = is_short = 1;
                } else {
                        if (likely(req->usb_req.length !=
                                   req->usb_req.actual) || req->usb_req.zero)
                                is_last = 0;
                        else
                                is_last = 1;
                }
                dev_dbg(udc->dev, "%s: wrote %s %d bytes%s%s %d left %p\n",
                        __func__, ep->ep_usb.name, length, is_last ? "/L" : "",
                        is_short ? "/S" : "",
                        req->usb_req.length - req->usb_req.actual, req);
                /* completion */
                if (is_last) {
                        xudc_done(ep, req, 0);
                        retval = 0;
                }
                break;
        case -EAGAIN:
                dev_dbg(udc->dev, "Send busy\n");
                break;
        case -EINVAL:
        case -ETIMEDOUT:
                /* DMA error, dequeue the request */
                xudc_done(ep, req, -ECONNRESET);
                retval = 0;
                break;
        }

        return retval;
}

/**
 * xudc_nuke - Cleans up the data transfer message list.
 * @ep: pointer to the usb device endpoint structure.
 * @status: Status of the data transfer.
 */
static void xudc_nuke(struct xusb_ep *ep, int status)
{
        struct xusb_req *req;

        while (!list_empty(&ep->queue)) {
                req = list_first_entry(&ep->queue, struct xusb_req, queue);
                xudc_done(ep, req, status);
        }
}

/**
 * xudc_ep_set_halt - Stalls/unstalls the given endpoint.
 * @_ep: pointer to the usb device endpoint structure.
 * @value: value to indicate stall/unstall.
 *
 * Return: 0 for success and error value on failure
 */
static int xudc_ep_set_halt(struct usb_ep *_ep, int value)
{
        struct xusb_ep *ep = to_xusb_ep(_ep);
        struct xusb_udc *udc;
        unsigned long flags;
        u32 epcfgreg;

        if (!_ep || (!ep->desc && ep->epnumber)) {
                pr_debug("%s: bad ep or descriptor\n", __func__);
                return -EINVAL;
        }
        udc = ep->udc;

        if (ep->is_in && (!list_empty(&ep->queue)) && value) {
                dev_dbg(udc->dev, "requests pending can't halt\n");
                return -EAGAIN;
        }

        if (ep->buffer0ready || ep->buffer1ready) {
                dev_dbg(udc->dev, "HW buffers busy can't halt\n");
                return -EAGAIN;
        }

        spin_lock_irqsave(&udc->lock, flags);

        if (value) {
                /* Stall the device.*/
                epcfgreg = udc->read_fn(udc->addr + ep->offset);
                epcfgreg |= XUSB_EP_CFG_STALL_MASK;
                udc->write_fn(udc->addr, ep->offset, epcfgreg);
        } else {
                /* Unstall the device.*/
                epcfgreg = udc->read_fn(udc->addr + ep->offset);
                epcfgreg &= ~XUSB_EP_CFG_STALL_MASK;
                udc->write_fn(udc->addr, ep->offset, epcfgreg);
                if (ep->epnumber) {
                        /* Reset the toggle bit.*/
                        epcfgreg = udc->read_fn(ep->udc->addr + ep->offset);
                        epcfgreg &= ~XUSB_EP_CFG_DATA_TOGGLE_MASK;
                        udc->write_fn(udc->addr, ep->offset, epcfgreg);
                }
        }

        spin_unlock_irqrestore(&udc->lock, flags);
        return 0;
}

/**
 * xudc_ep_enable - Enables the given endpoint.
 * @ep: pointer to the xusb endpoint structure.
 * @desc: pointer to usb endpoint descriptor.
 *
 * Return: 0 for success and error value on failure
 */
static int __xudc_ep_enable(struct xusb_ep *ep,
                            const struct usb_endpoint_descriptor *desc)
{
        struct xusb_udc *udc = ep->udc;
        u32 tmp;
        u32 epcfg;
        u32 ier;
        u16 maxpacket;

        ep->is_in = ((desc->bEndpointAddress & USB_DIR_IN) != 0);
        /* Bit 3...0:endpoint number */
        ep->epnumber = (desc->bEndpointAddress & 0x0f);
        ep->desc = desc;
        ep->ep_usb.desc = desc;
        tmp = desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
        ep->ep_usb.maxpacket = maxpacket = le16_to_cpu(desc->wMaxPacketSize);

        switch (tmp) {
        case USB_ENDPOINT_XFER_CONTROL:
                dev_dbg(udc->dev, "only one control endpoint\n");
                /* NON- ISO */
                ep->is_iso = 0;
                return -EINVAL;
        case USB_ENDPOINT_XFER_INT:
                /* NON- ISO */
                ep->is_iso = 0;
                if (maxpacket > 64) {
                        dev_dbg(udc->dev, "bogus maxpacket %d\n", maxpacket);
                        return -EINVAL;
                }
                break;
        case USB_ENDPOINT_XFER_BULK:
                /* NON- ISO */
                ep->is_iso = 0;
                if (!(is_power_of_2(maxpacket) && maxpacket >= 8 &&
                                maxpacket <= 512)) {
                        dev_dbg(udc->dev, "bogus maxpacket %d\n", maxpacket);
                        return -EINVAL;
                }
                break;
        case USB_ENDPOINT_XFER_ISOC:
                /* ISO */
                ep->is_iso = 1;
                break;
        }

        ep->buffer0ready = 0;
        ep->buffer1ready = 0;
        ep->curbufnum = 0;
        ep->rambase = rambase[ep->epnumber];
        xudc_epconfig(ep, udc);

        dev_dbg(udc->dev, "Enable Endpoint %d max pkt is %d\n",
                ep->epnumber, maxpacket);

        /* Enable the End point.*/
        epcfg = udc->read_fn(udc->addr + ep->offset);
        epcfg |= XUSB_EP_CFG_VALID_MASK;
        udc->write_fn(udc->addr, ep->offset, epcfg);
        if (ep->epnumber)
                ep->rambase <<= 2;

        /* Enable buffer completion interrupts for endpoint */
        ier = udc->read_fn(udc->addr + XUSB_IER_OFFSET);
        ier |= (XUSB_STATUS_INTR_BUFF_COMP_SHIFT_MASK << ep->epnumber);
        udc->write_fn(udc->addr, XUSB_IER_OFFSET, ier);

        /* for OUT endpoint set buffers ready to receive */
        if (ep->epnumber && !ep->is_in) {
                udc->write_fn(udc->addr, XUSB_BUFFREADY_OFFSET,
                              1 << ep->epnumber);
                ep->buffer0ready = 1;
                udc->write_fn(udc->addr, XUSB_BUFFREADY_OFFSET,
                             (1 << (ep->epnumber +
                              XUSB_STATUS_EP_BUFF2_SHIFT)));
                ep->buffer1ready = 1;
        }

        return 0;
}

/**
 * xudc_ep_enable - Enables the given endpoint.
 * @_ep: pointer to the usb endpoint structure.
 * @desc: pointer to usb endpoint descriptor.
 *
 * Return: 0 for success and error value on failure
 */
static int xudc_ep_enable(struct usb_ep *_ep,
                          const struct usb_endpoint_descriptor *desc)
{
        struct xusb_ep *ep;
        struct xusb_udc *udc;
        unsigned long flags;
        int ret;

        if (!_ep || !desc || desc->bDescriptorType != USB_DT_ENDPOINT) {
                pr_debug("%s: bad ep or descriptor\n", __func__);
                return -EINVAL;
        }

        ep = to_xusb_ep(_ep);
        udc = ep->udc;

        if (!udc->driver || udc->gadget.speed == USB_SPEED_UNKNOWN) {
                dev_dbg(udc->dev, "bogus device state\n");
                return -ESHUTDOWN;
        }

        spin_lock_irqsave(&udc->lock, flags);
        ret = __xudc_ep_enable(ep, desc);
        spin_unlock_irqrestore(&udc->lock, flags);

        return ret;
}

/**
 * xudc_ep_disable - Disables the given endpoint.
 * @_ep: pointer to the usb endpoint structure.
 *
 * Return: 0 for success and error value on failure
 */
static int xudc_ep_disable(struct usb_ep *_ep)
{
        struct xusb_ep *ep;
        unsigned long flags;
        u32 epcfg;
        struct xusb_udc *udc;

        if (!_ep) {
                pr_debug("%s: invalid ep\n", __func__);
                return -EINVAL;
        }

        ep = to_xusb_ep(_ep);
        udc = ep->udc;

        spin_lock_irqsave(&udc->lock, flags);

        xudc_nuke(ep, -ESHUTDOWN);

        /* Restore the endpoint's pristine config */
        ep->desc = NULL;
        ep->ep_usb.desc = NULL;

        dev_dbg(udc->dev, "USB Ep %d disable\n ", ep->epnumber);
        /* Disable the endpoint.*/
        epcfg = udc->read_fn(udc->addr + ep->offset);
        epcfg &= ~XUSB_EP_CFG_VALID_MASK;
        udc->write_fn(udc->addr, ep->offset, epcfg);

        spin_unlock_irqrestore(&udc->lock, flags);
        return 0;
}

/**
 * xudc_ep_alloc_request - Initializes the request queue.
 * @_ep: pointer to the usb endpoint structure.
 * @gfp_flags: Flags related to the request call.
 *
 * Return: pointer to request structure on success and a NULL on failure.
 */
static struct usb_request *xudc_ep_alloc_request(struct usb_ep *_ep,
                                                 gfp_t gfp_flags)
{
        struct xusb_ep *ep = to_xusb_ep(_ep);
        struct xusb_udc *udc;
        struct xusb_req *req;

        udc = ep->udc;
        req = kzalloc(sizeof(*req), gfp_flags);
        if (!req) {
                dev_err(udc->dev, "%s:not enough memory", __func__);
                return NULL;
        }

        req->ep = ep;
        INIT_LIST_HEAD(&req->queue);
        return &req->usb_req;
}

/**
 * xudc_free_request - Releases the request from queue.
 * @_ep: pointer to the usb device endpoint structure.
 * @_req: pointer to the usb request structure.
 */
static void xudc_free_request(struct usb_ep *_ep, struct usb_request *_req)
{
        struct xusb_req *req = to_xusb_req(_req);

        kfree(req);
}

/**
 * xudc_ep0_queue - Adds the request to endpoint 0 queue.
 * @ep0: pointer to the xusb endpoint 0 structure.

 * @req: pointer to the xusb request structure.
 *
 * Return: 0 for success and error value on failure
 */
static int __xudc_ep0_queue(struct xusb_ep *ep0, struct xusb_req *req)
{
        struct xusb_udc *udc = ep0->udc;
        u32 length;
        u8 *corebuf;

        if (!udc->driver || udc->gadget.speed == USB_SPEED_UNKNOWN) {
                dev_dbg(udc->dev, "%s, bogus device state\n", __func__);
                return -EINVAL;
        }
        if (!list_empty(&ep0->queue)) {
                dev_dbg(udc->dev, "%s:ep0 busy\n", __func__);
                return -EBUSY;
        }

        req->usb_req.status = -EINPROGRESS;
        req->usb_req.actual = 0;

        list_add_tail(&req->queue, &ep0->queue);

        if (udc->setup.bRequestType & USB_DIR_IN) {
                prefetch(req->usb_req.buf);
                length = req->usb_req.length;
                corebuf = (void __force *) ((ep0->rambase << 2) +
                           udc->addr);
                length = req->usb_req.actual = min_t(u32, length,
                                                     EP0_MAX_PACKET);
                memcpy(corebuf, req->usb_req.buf, length);
                udc->write_fn(udc->addr, XUSB_EP_BUF0COUNT_OFFSET, length);
                udc->write_fn(udc->addr, XUSB_BUFFREADY_OFFSET, 1);
        } else {
                if (udc->setup.wLength) {
                        /* Enable EP0 buffer to receive data */
                        udc->write_fn(udc->addr, XUSB_EP_BUF0COUNT_OFFSET, 0);
                        udc->write_fn(udc->addr, XUSB_BUFFREADY_OFFSET, 1);
                } else {
                        xudc_wrstatus(udc);
                }
        }

        return 0;
}

/**
 * xudc_ep0_queue - Adds the request to endpoint 0 queue.
 * @_ep: pointer to the usb endpoint 0 structure.
 * @_req: pointer to the usb request structure.
 * @gfp_flags: Flags related to the request call.
 *
 * Return: 0 for success and error value on failure
 */
static int xudc_ep0_queue(struct usb_ep *_ep, struct usb_request *_req,
                          gfp_t gfp_flags)
{
        struct xusb_req *req    = to_xusb_req(_req);
        struct xusb_ep  *ep0    = to_xusb_ep(_ep);
        struct xusb_udc *udc    = ep0->udc;
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&udc->lock, flags);
        ret = __xudc_ep0_queue(ep0, req);
        spin_unlock_irqrestore(&udc->lock, flags);

        return ret;
}

/**
 * xudc_ep_queue - Adds the request to endpoint queue.
 * @_ep: pointer to the usb endpoint structure.
 * @_req: pointer to the usb request structure.
 * @gfp_flags: Flags related to the request call.
 *
 * Return: 0 for success and error value on failure
 */
static int xudc_ep_queue(struct usb_ep *_ep, struct usb_request *_req,
                         gfp_t gfp_flags)
{
        struct xusb_req *req = to_xusb_req(_req);
        struct xusb_ep  *ep  = to_xusb_ep(_ep);
        struct xusb_udc *udc = ep->udc;
        int  ret;
        unsigned long flags;

        if (!ep->desc) {
                dev_dbg(udc->dev, "%s:queing request to disabled %s\n",
                        __func__, ep->name);
                return -ESHUTDOWN;
        }

        if (!udc->driver || udc->gadget.speed == USB_SPEED_UNKNOWN) {
                dev_dbg(udc->dev, "%s, bogus device state\n", __func__);
                return -EINVAL;
        }

        spin_lock_irqsave(&udc->lock, flags);

        _req->status = -EINPROGRESS;
        _req->actual = 0;

        if (udc->dma_enabled) {
                ret = usb_gadget_map_request(&udc->gadget, &req->usb_req,
                                             ep->is_in);
                if (ret) {
                        dev_dbg(udc->dev, "gadget_map failed ep%d\n",
                                ep->epnumber);
                        spin_unlock_irqrestore(&udc->lock, flags);
                        return -EAGAIN;
                }
        }

        if (list_empty(&ep->queue)) {
                if (ep->is_in) {
                        dev_dbg(udc->dev, "xudc_write_fifo from ep_queue\n");
                        if (!xudc_write_fifo(ep, req))
                                req = NULL;
                } else {
                        dev_dbg(udc->dev, "xudc_read_fifo from ep_queue\n");
                        if (!xudc_read_fifo(ep, req))
                                req = NULL;
                }
        }

        if (req != NULL)
                list_add_tail(&req->queue, &ep->queue);

        spin_unlock_irqrestore(&udc->lock, flags);
        return 0;
}

/**
 * xudc_ep_dequeue - Removes the request from the queue.
 * @_ep: pointer to the usb device endpoint structure.
 * @_req: pointer to the usb request structure.
 *
 * Return: 0 for success and error value on failure
 */
static int xudc_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
{
        struct xusb_ep *ep      = to_xusb_ep(_ep);
        struct xusb_req *req    = to_xusb_req(_req);
        struct xusb_udc *udc    = ep->udc;
        unsigned long flags;

        spin_lock_irqsave(&udc->lock, flags);
        /* Make sure it's actually queued on this endpoint */
        list_for_each_entry(req, &ep->queue, queue) {
                if (&req->usb_req == _req)
                        break;
        }
        if (&req->usb_req != _req) {
                spin_unlock_irqrestore(&ep->udc->lock, flags);
                return -EINVAL;
        }
        xudc_done(ep, req, -ECONNRESET);
        spin_unlock_irqrestore(&udc->lock, flags);

        return 0;
}

/**
 * xudc_ep0_enable - Enables the given endpoint.
 * @ep: pointer to the usb endpoint structure.
 * @desc: pointer to usb endpoint descriptor.
 *
 * Return: error always.
 *
 * endpoint 0 enable should not be called by gadget layer.
 */
static int xudc_ep0_enable(struct usb_ep *ep,
                           const struct usb_endpoint_descriptor *desc)
{
        return -EINVAL;
}

/**
 * xudc_ep0_disable - Disables the given endpoint.
 * @ep: pointer to the usb endpoint structure.
 *
 * Return: error always.
 *
 * endpoint 0 disable should not be called by gadget layer.
 */
static int xudc_ep0_disable(struct usb_ep *ep)
{
        return -EINVAL;
}

static const struct usb_ep_ops xusb_ep0_ops = {
        .enable         = xudc_ep0_enable,
        .disable        = xudc_ep0_disable,
        .alloc_request  = xudc_ep_alloc_request,
        .free_request   = xudc_free_request,
        .queue          = xudc_ep0_queue,
        .dequeue        = xudc_ep_dequeue,
        .set_halt       = xudc_ep_set_halt,
};

static const struct usb_ep_ops xusb_ep_ops = {
        .enable         = xudc_ep_enable,
        .disable        = xudc_ep_disable,
        .alloc_request  = xudc_ep_alloc_request,
        .free_request   = xudc_free_request,
        .queue          = xudc_ep_queue,
        .dequeue        = xudc_ep_dequeue,
        .set_halt       = xudc_ep_set_halt,
};

/**
 * xudc_get_frame - Reads the current usb frame number.
 * @gadget: pointer to the usb gadget structure.
 *
 * Return: current frame number for success and error value on failure.
 */
static int xudc_get_frame(struct usb_gadget *gadget)
{
        struct xusb_udc *udc;
        int frame;

        if (!gadget)
                return -ENODEV;

        udc = to_udc(gadget);
        frame = udc->read_fn(udc->addr + XUSB_FRAMENUM_OFFSET);
        return frame;
}

/**
 * xudc_wakeup - Send remote wakeup signal to host
 * @gadget: pointer to the usb gadget structure.
 *
 * Return: 0 on success and error on failure
 */
static int xudc_wakeup(struct usb_gadget *gadget)
{
        struct xusb_udc *udc = to_udc(gadget);
        u32 crtlreg;
        int status = -EINVAL;
        unsigned long flags;

        spin_lock_irqsave(&udc->lock, flags);

        /* Remote wake up not enabled by host */
        if (!udc->remote_wkp)
                goto done;

        crtlreg = udc->read_fn(udc->addr + XUSB_CONTROL_OFFSET);
        crtlreg |= XUSB_CONTROL_USB_RMTWAKE_MASK;
        /* set remote wake up bit */
        udc->write_fn(udc->addr, XUSB_CONTROL_OFFSET, crtlreg);
        /*
         * wait for a while and reset remote wake up bit since this bit
         * is not cleared by HW after sending remote wakeup to host.
         */
        mdelay(2);

        crtlreg &= ~XUSB_CONTROL_USB_RMTWAKE_MASK;
        udc->write_fn(udc->addr, XUSB_CONTROL_OFFSET, crtlreg);
        status = 0;
done:
        spin_unlock_irqrestore(&udc->lock, flags);
        return status;
}

/**
 * xudc_pullup - start/stop USB traffic
 * @gadget: pointer to the usb gadget structure.
 * @is_on: flag to start or stop
 *
 * Return: 0 always
 *
 * This function starts/stops SIE engine of IP based on is_on.
 */
static int xudc_pullup(struct usb_gadget *gadget, int is_on)
{
        struct xusb_udc *udc = to_udc(gadget);
        unsigned long flags;
        u32 crtlreg;

        spin_lock_irqsave(&udc->lock, flags);

        crtlreg = udc->read_fn(udc->addr + XUSB_CONTROL_OFFSET);
        if (is_on)
                crtlreg |= XUSB_CONTROL_USB_READY_MASK;
        else
                crtlreg &= ~XUSB_CONTROL_USB_READY_MASK;

        udc->write_fn(udc->addr, XUSB_CONTROL_OFFSET, crtlreg);

        spin_unlock_irqrestore(&udc->lock, flags);

        return 0;
}

/**
 * xudc_eps_init - initialize endpoints.
 * @udc: pointer to the usb device controller structure.
 */
static void xudc_eps_init(struct xusb_udc *udc)
{
        u32 ep_number;

        INIT_LIST_HEAD(&udc->gadget.ep_list);

        for (ep_number = 0; ep_number < XUSB_MAX_ENDPOINTS; ep_number++) {
                struct xusb_ep *ep = &udc->ep[ep_number];

                if (ep_number) {
                        list_add_tail(&ep->ep_usb.ep_list,
                                      &udc->gadget.ep_list);
                        usb_ep_set_maxpacket_limit(&ep->ep_usb,
                                                  (unsigned short) ~0);
                        snprintf(ep->name, EPNAME_SIZE, "ep%d", ep_number);
                        ep->ep_usb.name = ep->name;
                        ep->ep_usb.ops = &xusb_ep_ops;
                } else {
                        ep->ep_usb.name = ep0name;
                        usb_ep_set_maxpacket_limit(&ep->ep_usb, EP0_MAX_PACKET);
                        ep->ep_usb.ops = &xusb_ep0_ops;
                }

                ep->udc = udc;
                ep->epnumber = ep_number;
                ep->desc = NULL;
                /*
                 * The configuration register address offset between
                 * each endpoint is 0x10.
                 */
                ep->offset = XUSB_EP0_CONFIG_OFFSET + (ep_number * 0x10);
                ep->is_in = 0;
                ep->is_iso = 0;
                ep->maxpacket = 0;
                xudc_epconfig(ep, udc);

                /* Initialize one queue per endpoint */
                INIT_LIST_HEAD(&ep->queue);
        }
}

/**
 * xudc_stop_activity - Stops any further activity on the device.
 * @udc: pointer to the usb device controller structure.
 */
static void xudc_stop_activity(struct xusb_udc *udc)
{
        int i;
        struct xusb_ep *ep;

        for (i = 0; i < XUSB_MAX_ENDPOINTS; i++) {
                ep = &udc->ep[i];
                xudc_nuke(ep, -ESHUTDOWN);
        }
}

/**
 * xudc_start - Starts the device.
 * @gadget: pointer to the usb gadget structure
 * @driver: pointer to gadget driver structure
 *
 * Return: zero on success and error on failure
 */
static int xudc_start(struct usb_gadget *gadget,
                      struct usb_gadget_driver *driver)
{
        struct xusb_udc *udc    = to_udc(gadget);
        struct xusb_ep *ep0     = &udc->ep[XUSB_EP_NUMBER_ZERO];
        const struct usb_endpoint_descriptor *desc = &config_bulk_out_desc;
        unsigned long flags;
        int ret = 0;

        spin_lock_irqsave(&udc->lock, flags);

        if (udc->driver) {
                dev_err(udc->dev, "%s is already bound to %s\n",
                        udc->gadget.name, udc->driver->driver.name);
                ret = -EBUSY;
                goto err;
        }

        /* hook up the driver */
        udc->driver = driver;
        udc->gadget.speed = driver->max_speed;

        /* Enable the control endpoint. */
        ret = __xudc_ep_enable(ep0, desc);

        /* Set device address and remote wakeup to 0 */
        udc->write_fn(udc->addr, XUSB_ADDRESS_OFFSET, 0);
        udc->remote_wkp = 0;
err:
        spin_unlock_irqrestore(&udc->lock, flags);
        return ret;
}

/**
 * xudc_stop - stops the device.
 * @gadget: pointer to the usb gadget structure
 * @driver: pointer to usb gadget driver structure
 *
 * Return: zero always
 */
static int xudc_stop(struct usb_gadget *gadget)
{
        struct xusb_udc *udc = to_udc(gadget);
        unsigned long flags;

        spin_lock_irqsave(&udc->lock, flags);

        udc->gadget.speed = USB_SPEED_UNKNOWN;
        udc->driver = NULL;

        /* Set device address and remote wakeup to 0 */
        udc->write_fn(udc->addr, XUSB_ADDRESS_OFFSET, 0);
        udc->remote_wkp = 0;

        xudc_stop_activity(udc);

        spin_unlock_irqrestore(&udc->lock, flags);

        return 0;
}

static const struct usb_gadget_ops xusb_udc_ops = {
        .get_frame      = xudc_get_frame,
        .wakeup         = xudc_wakeup,
        .pullup         = xudc_pullup,
        .udc_start      = xudc_start,
        .udc_stop       = xudc_stop,
};

/**
 * xudc_clear_stall_all_ep - clears stall of every endpoint.
 * @udc: pointer to the udc structure.
 */
static void xudc_clear_stall_all_ep(struct xusb_udc *udc)
{
        struct xusb_ep *ep;
        u32 epcfgreg;
        int i;

        for (i = 0; i < XUSB_MAX_ENDPOINTS; i++) {
                ep = &udc->ep[i];
                epcfgreg = udc->read_fn(udc->addr + ep->offset);
                epcfgreg &= ~XUSB_EP_CFG_STALL_MASK;
                udc->write_fn(udc->addr, ep->offset, epcfgreg);
                if (ep->epnumber) {
                        /* Reset the toggle bit.*/
                        epcfgreg = udc->read_fn(udc->addr + ep->offset);
                        epcfgreg &= ~XUSB_EP_CFG_DATA_TOGGLE_MASK;
                        udc->write_fn(udc->addr, ep->offset, epcfgreg);
                }
        }
}

/**
 * xudc_startup_handler - The usb device controller interrupt handler.
 * @udc: pointer to the udc structure.
 * @intrstatus: The mask value containing the interrupt sources.
 *
 * This function handles the RESET,SUSPEND,RESUME and DISCONNECT interrupts.
 */
static void xudc_startup_handler(struct xusb_udc *udc, u32 intrstatus)
{
        u32 intrreg;

        if (intrstatus & XUSB_STATUS_RESET_MASK) {

                dev_dbg(udc->dev, "Reset\n");

                if (intrstatus & XUSB_STATUS_HIGH_SPEED_MASK)
                        udc->gadget.speed = USB_SPEED_HIGH;
                else
                        udc->gadget.speed = USB_SPEED_FULL;

                xudc_stop_activity(udc);
                xudc_clear_stall_all_ep(udc);
                udc->write_fn(udc->addr, XUSB_TESTMODE_OFFSET, 0);

                /* Set device address and remote wakeup to 0 */
                udc->write_fn(udc->addr, XUSB_ADDRESS_OFFSET, 0);
                udc->remote_wkp = 0;

                /* Enable the suspend, resume and disconnect */
                intrreg = udc->read_fn(udc->addr + XUSB_IER_OFFSET);
                intrreg |= XUSB_STATUS_SUSPEND_MASK | XUSB_STATUS_RESUME_MASK |
                           XUSB_STATUS_DISCONNECT_MASK;
                udc->write_fn(udc->addr, XUSB_IER_OFFSET, intrreg);
        }
        if (intrstatus & XUSB_STATUS_SUSPEND_MASK) {

                dev_dbg(udc->dev, "Suspend\n");

                /* Enable the reset, resume and disconnect */
                intrreg = udc->read_fn(udc->addr + XUSB_IER_OFFSET);
                intrreg |= XUSB_STATUS_RESET_MASK | XUSB_STATUS_RESUME_MASK |
                           XUSB_STATUS_DISCONNECT_MASK;
                udc->write_fn(udc->addr, XUSB_IER_OFFSET, intrreg);

                udc->usb_state = USB_STATE_SUSPENDED;

                if (udc->driver->suspend) {
                        spin_unlock(&udc->lock);
                        udc->driver->suspend(&udc->gadget);
                        spin_lock(&udc->lock);
                }
        }
        if (intrstatus & XUSB_STATUS_RESUME_MASK) {
                bool condition = (udc->usb_state != USB_STATE_SUSPENDED);

                dev_WARN_ONCE(udc->dev, condition,
                                "Resume IRQ while not suspended\n");

                dev_dbg(udc->dev, "Resume\n");

                /* Enable the reset, suspend and disconnect */
                intrreg = udc->read_fn(udc->addr + XUSB_IER_OFFSET);
                intrreg |= XUSB_STATUS_RESET_MASK | XUSB_STATUS_SUSPEND_MASK |
                           XUSB_STATUS_DISCONNECT_MASK;
                udc->write_fn(udc->addr, XUSB_IER_OFFSET, intrreg);

                udc->usb_state = 0;

                if (udc->driver->resume) {
                        spin_unlock(&udc->lock);
                        udc->driver->resume(&udc->gadget);
                        spin_lock(&udc->lock);
                }
        }
        if (intrstatus & XUSB_STATUS_DISCONNECT_MASK) {

                dev_dbg(udc->dev, "Disconnect\n");

                /* Enable the reset, resume and suspend */
                intrreg = udc->read_fn(udc->addr + XUSB_IER_OFFSET);
                intrreg |= XUSB_STATUS_RESET_MASK | XUSB_STATUS_RESUME_MASK |
                           XUSB_STATUS_SUSPEND_MASK;
                udc->write_fn(udc->addr, XUSB_IER_OFFSET, intrreg);

                if (udc->driver && udc->driver->disconnect) {
                        spin_unlock(&udc->lock);
                        udc->driver->disconnect(&udc->gadget);
                        spin_lock(&udc->lock);
                }
        }
}

/**
 * xudc_ep0_stall - Stall endpoint zero.
 * @udc: pointer to the udc structure.
 *
 * This function stalls endpoint zero.
 */
static void xudc_ep0_stall(struct xusb_udc *udc)
{
        u32 epcfgreg;
        struct xusb_ep *ep0 = &udc->ep[XUSB_EP_NUMBER_ZERO];

        epcfgreg = udc->read_fn(udc->addr + ep0->offset);
        epcfgreg |= XUSB_EP_CFG_STALL_MASK;
        udc->write_fn(udc->addr, ep0->offset, epcfgreg);
}

/**
 * xudc_setaddress - executes SET_ADDRESS command
 * @udc: pointer to the udc structure.
 *
 * This function executes USB SET_ADDRESS command
 */
static void xudc_setaddress(struct xusb_udc *udc)
{
        struct xusb_ep *ep0     = &udc->ep[0];
        struct xusb_req *req    = udc->req;
        int ret;

        req->usb_req.length = 0;
        ret = __xudc_ep0_queue(ep0, req);
        if (ret == 0)
                return;

        dev_err(udc->dev, "Can't respond to SET ADDRESS request\n");
        xudc_ep0_stall(udc);
}

/**
 * xudc_getstatus - executes GET_STATUS command
 * @udc: pointer to the udc structure.
 *
 * This function executes USB GET_STATUS command
 */
static void xudc_getstatus(struct xusb_udc *udc)
{
        struct xusb_ep *ep0     = &udc->ep[0];
        struct xusb_req *req    = udc->req;
        struct xusb_ep *target_ep;
        u16 status = 0;
        u32 epcfgreg;
        int epnum;
        u32 halt;
        int ret;

        switch (udc->setup.bRequestType & USB_RECIP_MASK) {
        case USB_RECIP_DEVICE:
                /* Get device status */
                status = 1 << USB_DEVICE_SELF_POWERED;
                if (udc->remote_wkp)
                        status |= (1 << USB_DEVICE_REMOTE_WAKEUP);
                break;
        case USB_RECIP_INTERFACE:
                break;
        case USB_RECIP_ENDPOINT:
                epnum = udc->setup.wIndex & USB_ENDPOINT_NUMBER_MASK;
                target_ep = &udc->ep[epnum];
                epcfgreg = udc->read_fn(udc->addr + target_ep->offset);
                halt = epcfgreg & XUSB_EP_CFG_STALL_MASK;
                if (udc->setup.wIndex & USB_DIR_IN) {
                        if (!target_ep->is_in)
                                goto stall;
                } else {
                        if (target_ep->is_in)
                                goto stall;
                }
                if (halt)
                        status = 1 << USB_ENDPOINT_HALT;
                break;
        default:
                goto stall;
        }

        req->usb_req.length = 2;
        *(u16 *)req->usb_req.buf = cpu_to_le16(status);
        ret = __xudc_ep0_queue(ep0, req);
        if (ret == 0)
                return;
stall:
        dev_err(udc->dev, "Can't respond to getstatus request\n");
        xudc_ep0_stall(udc);
}

/**
 * xudc_set_clear_feature - Executes the set feature and clear feature commands.
 * @udc: pointer to the usb device controller structure.
 *
 * Processes the SET_FEATURE and CLEAR_FEATURE commands.
 */
static void xudc_set_clear_feature(struct xusb_udc *udc)
{
        struct xusb_ep *ep0     = &udc->ep[0];
        struct xusb_req *req    = udc->req;
        struct xusb_ep *target_ep;
        u8 endpoint;
        u8 outinbit;
        u32 epcfgreg;
        int flag = (udc->setup.bRequest == USB_REQ_SET_FEATURE ? 1 : 0);
        int ret;

        switch (udc->setup.bRequestType) {
        case USB_RECIP_DEVICE:
                switch (udc->setup.wValue) {
                case USB_DEVICE_TEST_MODE:
                        /*
                         * The Test Mode will be executed
                         * after the status phase.
                         */
                        break;
                case USB_DEVICE_REMOTE_WAKEUP:
                        if (flag)
                                udc->remote_wkp = 1;
                        else
                                udc->remote_wkp = 0;
                        break;
                default:
                        xudc_ep0_stall(udc);
                        break;
                }
                break;
        case USB_RECIP_ENDPOINT:
                if (!udc->setup.wValue) {
                        endpoint = udc->setup.wIndex & USB_ENDPOINT_NUMBER_MASK;
                        target_ep = &udc->ep[endpoint];
                        outinbit = udc->setup.wIndex & USB_ENDPOINT_DIR_MASK;
                        outinbit = outinbit >> 7;

                        /* Make sure direction matches.*/
                        if (outinbit != target_ep->is_in) {
                                xudc_ep0_stall(udc);
                                return;
                        }
                        epcfgreg = udc->read_fn(udc->addr + target_ep->offset);
                        if (!endpoint) {
                                /* Clear the stall.*/
                                epcfgreg &= ~XUSB_EP_CFG_STALL_MASK;
                                udc->write_fn(udc->addr,
                                              target_ep->offset, epcfgreg);
                        } else {
                                if (flag) {
                                        epcfgreg |= XUSB_EP_CFG_STALL_MASK;
                                        udc->write_fn(udc->addr,
                                                      target_ep->offset,
                                                      epcfgreg);
                                } else {
                                        /* Unstall the endpoint.*/
                                        epcfgreg &= ~(XUSB_EP_CFG_STALL_MASK |
                                                XUSB_EP_CFG_DATA_TOGGLE_MASK);
                                        udc->write_fn(udc->addr,
                                                      target_ep->offset,
                                                      epcfgreg);
                                }
                        }
                }
                break;
        default:
                xudc_ep0_stall(udc);
                return;
        }

        req->usb_req.length = 0;
        ret = __xudc_ep0_queue(ep0, req);
        if (ret == 0)
                return;

        dev_err(udc->dev, "Can't respond to SET/CLEAR FEATURE\n");
        xudc_ep0_stall(udc);
}

/**
 * xudc_handle_setup - Processes the setup packet.
 * @udc: pointer to the usb device controller structure.
 *
 * Process setup packet and delegate to gadget layer.
 */
static void xudc_handle_setup(struct xusb_udc *udc)
{
        struct xusb_ep *ep0 = &udc->ep[0];
        struct usb_ctrlrequest setup;
        u32 *ep0rambase;

        /* Load up the chapter 9 command buffer.*/
        ep0rambase = (u32 __force *) (udc->addr + XUSB_SETUP_PKT_ADDR_OFFSET);
        memcpy(&setup, ep0rambase, 8);

        udc->setup = setup;
        udc->setup.wValue = cpu_to_le16(setup.wValue);
        udc->setup.wIndex = cpu_to_le16(setup.wIndex);
        udc->setup.wLength = cpu_to_le16(setup.wLength);

        /* Clear previous requests */
        xudc_nuke(ep0, -ECONNRESET);

        if (udc->setup.bRequestType & USB_DIR_IN) {
                /* Execute the get command.*/
                udc->setupseqrx = STATUS_PHASE;
                udc->setupseqtx = DATA_PHASE;
        } else {
                /* Execute the put command.*/
                udc->setupseqrx = DATA_PHASE;
                udc->setupseqtx = STATUS_PHASE;
        }

        switch (udc->setup.bRequest) {
        case USB_REQ_GET_STATUS:
                /* Data+Status phase form udc */
                if ((udc->setup.bRequestType &
                                (USB_DIR_IN | USB_TYPE_MASK)) !=
                                (USB_DIR_IN | USB_TYPE_STANDARD))
                        break;
                xudc_getstatus(udc);
                return;
        case USB_REQ_SET_ADDRESS:
                /* Status phase from udc */
                if (udc->setup.bRequestType != (USB_DIR_OUT |
                                USB_TYPE_STANDARD | USB_RECIP_DEVICE))
                        break;
                xudc_setaddress(udc);
                return;
        case USB_REQ_CLEAR_FEATURE:
        case USB_REQ_SET_FEATURE:
                /* Requests with no data phase, status phase from udc */
                if ((udc->setup.bRequestType & USB_TYPE_MASK)
                                != USB_TYPE_STANDARD)
                        break;
                xudc_set_clear_feature(udc);
                return;
        default:
                break;
        }

        spin_unlock(&udc->lock);
        if (udc->driver->setup(&udc->gadget, &setup) < 0)
                xudc_ep0_stall(udc);
        spin_lock(&udc->lock);
}

/**
 * xudc_ep0_out - Processes the endpoint 0 OUT token.
 * @udc: pointer to the usb device controller structure.
 */
static void xudc_ep0_out(struct xusb_udc *udc)
{
        struct xusb_ep *ep0 = &udc->ep[0];
        struct xusb_req *req;
        u8 *ep0rambase;
        unsigned int bytes_to_rx;
        void *buffer;

        req = list_first_entry(&ep0->queue, struct xusb_req, queue);

        switch (udc->setupseqrx) {
        case STATUS_PHASE:
                /*
                 * This resets both state machines for the next
                 * Setup packet.
                 */
                udc->setupseqrx = SETUP_PHASE;
                udc->setupseqtx = SETUP_PHASE;
                req->usb_req.actual = req->usb_req.length;
                xudc_done(ep0, req, 0);
                break;
        case DATA_PHASE:
                bytes_to_rx = udc->read_fn(udc->addr +
                                           XUSB_EP_BUF0COUNT_OFFSET);
                /* Copy the data to be received from the DPRAM. */
                ep0rambase = (u8 __force *) (udc->addr +
                             (ep0->rambase << 2));
                buffer = req->usb_req.buf + req->usb_req.actual;
                req->usb_req.actual = req->usb_req.actual + bytes_to_rx;
                memcpy(buffer, ep0rambase, bytes_to_rx);

                if (req->usb_req.length == req->usb_req.actual) {
                        /* Data transfer completed get ready for Status stage */
                        xudc_wrstatus(udc);
                } else {
                        /* Enable EP0 buffer to receive data */
                        udc->write_fn(udc->addr, XUSB_EP_BUF0COUNT_OFFSET, 0);
                        udc->write_fn(udc->addr, XUSB_BUFFREADY_OFFSET, 1);
                }
                break;
        default:
                break;
        }
}

/**
 * xudc_ep0_in - Processes the endpoint 0 IN token.
 * @udc: pointer to the usb device controller structure.
 */
static void xudc_ep0_in(struct xusb_udc *udc)
{
        struct xusb_ep *ep0 = &udc->ep[0];
        struct xusb_req *req;
        unsigned int bytes_to_tx;
        void *buffer;
        u32 epcfgreg;
        u16 count = 0;
        u16 length;
        u8 *ep0rambase;
        u8 test_mode = udc->setup.wIndex >> 8;

        req = list_first_entry(&ep0->queue, struct xusb_req, queue);
        bytes_to_tx = req->usb_req.length - req->usb_req.actual;

        switch (udc->setupseqtx) {
        case STATUS_PHASE:
                switch (udc->setup.bRequest) {
                case USB_REQ_SET_ADDRESS:
                        /* Set the address of the device.*/
                        udc->write_fn(udc->addr, XUSB_ADDRESS_OFFSET,
                                      udc->setup.wValue);
                        break;
                case USB_REQ_SET_FEATURE:
                        if (udc->setup.bRequestType ==
                                        USB_RECIP_DEVICE) {
                                if (udc->setup.wValue ==
                                                USB_DEVICE_TEST_MODE)
                                        udc->write_fn(udc->addr,
                                                      XUSB_TESTMODE_OFFSET,
                                                      test_mode);
                        }
                        break;
                }
                req->usb_req.actual = req->usb_req.length;
                xudc_done(ep0, req, 0);
                break;
        case DATA_PHASE:
                if (!bytes_to_tx) {
                        /*
                         * We're done with data transfer, next
                         * will be zero length OUT with data toggle of
                         * 1. Setup data_toggle.
                         */
                        epcfgreg = udc->read_fn(udc->addr + ep0->offset);
                        epcfgreg |= XUSB_EP_CFG_DATA_TOGGLE_MASK;
                        udc->write_fn(udc->addr, ep0->offset, epcfgreg);
                        udc->setupseqtx = STATUS_PHASE;
                } else {
                        length = count = min_t(u32, bytes_to_tx,
                                               EP0_MAX_PACKET);
                        /* Copy the data to be transmitted into the DPRAM. */
                        ep0rambase = (u8 __force *) (udc->addr +
                                     (ep0->rambase << 2));
                        buffer = req->usb_req.buf + req->usb_req.actual;
                        req->usb_req.actual = req->usb_req.actual + length;
                        memcpy(ep0rambase, buffer, length);
                }
                udc->write_fn(udc->addr, XUSB_EP_BUF0COUNT_OFFSET, count);
                udc->write_fn(udc->addr, XUSB_BUFFREADY_OFFSET, 1);
                break;
        default:
                break;
        }
}

/**
 * xudc_ctrl_ep_handler - Endpoint 0 interrupt handler.
 * @udc: pointer to the udc structure.
 * @intrstatus: It's the mask value for the interrupt sources on endpoint 0.
 *
 * Processes the commands received during enumeration phase.
 */
static void xudc_ctrl_ep_handler(struct xusb_udc *udc, u32 intrstatus)
{

        if (intrstatus & XUSB_STATUS_SETUP_PACKET_MASK) {
                xudc_handle_setup(udc);
        } else {
                if (intrstatus & XUSB_STATUS_FIFO_BUFF_RDY_MASK)
                        xudc_ep0_out(udc);
                else if (intrstatus & XUSB_STATUS_FIFO_BUFF_FREE_MASK)
                        xudc_ep0_in(udc);
        }
}

/**
 * xudc_nonctrl_ep_handler - Non control endpoint interrupt handler.
 * @udc: pointer to the udc structure.
 * @epnum: End point number for which the interrupt is to be processed
 * @intrstatus: mask value for interrupt sources of endpoints other
 *              than endpoint 0.
 *
 * Processes the buffer completion interrupts.
 */
static void xudc_nonctrl_ep_handler(struct xusb_udc *udc, u8 epnum,
                                    u32 intrstatus)
{

        struct xusb_req *req;
        struct xusb_ep *ep;

        ep = &udc->ep[epnum];
        /* Process the End point interrupts.*/
        if (intrstatus & (XUSB_STATUS_EP0_BUFF1_COMP_MASK << epnum))
                ep->buffer0ready = 0;
        if (intrstatus & (XUSB_STATUS_EP0_BUFF2_COMP_MASK << epnum))
                ep->buffer1ready = 0;

        if (list_empty(&ep->queue))
                return;

        req = list_first_entry(&ep->queue, struct xusb_req, queue);

        if (ep->is_in)
                xudc_write_fifo(ep, req);
        else
                xudc_read_fifo(ep, req);
}

/**
 * xudc_irq - The main interrupt handler.
 * @irq: The interrupt number.
 * @_udc: pointer to the usb device controller structure.
 *
 * Return: IRQ_HANDLED after the interrupt is handled.
 */
static irqreturn_t xudc_irq(int irq, void *_udc)
{
        struct xusb_udc *udc = _udc;
        u32 intrstatus;
        u32 ier;
        u8 index;
        u32 bufintr;
        unsigned long flags;

        spin_lock_irqsave(&udc->lock, flags);

        /*
         * Event interrupts are level sensitive hence first disable
         * IER, read ISR and figure out active interrupts.
         */
        ier = udc->read_fn(udc->addr + XUSB_IER_OFFSET);
        ier &= ~XUSB_STATUS_INTR_EVENT_MASK;
        udc->write_fn(udc->addr, XUSB_IER_OFFSET, ier);

        /* Read the Interrupt Status Register.*/
        intrstatus = udc->read_fn(udc->addr + XUSB_STATUS_OFFSET);

        /* Call the handler for the event interrupt.*/
        if (intrstatus & XUSB_STATUS_INTR_EVENT_MASK) {

                /*
                 * Check if there is any action to be done for :
                 * - USB Reset received {XUSB_STATUS_RESET_MASK}
                 * - USB Suspend received {XUSB_STATUS_SUSPEND_MASK}
                 * - USB Resume received {XUSB_STATUS_RESUME_MASK}
                 * - USB Disconnect received {XUSB_STATUS_DISCONNECT_MASK}
                 */
                xudc_startup_handler(udc, intrstatus);
        }

        /* Check the buffer completion interrupts */
        if (intrstatus & XUSB_STATUS_INTR_BUFF_COMP_ALL_MASK) {
                /* Enable Reset, Suspend, Resume and Disconnect  */
                ier = udc->read_fn(udc->addr + XUSB_IER_OFFSET);
                ier |= XUSB_STATUS_INTR_EVENT_MASK;
                udc->write_fn(udc->addr, XUSB_IER_OFFSET, ier);

                if (intrstatus & XUSB_STATUS_EP0_BUFF1_COMP_MASK)
                        xudc_ctrl_ep_handler(udc, intrstatus);

                for (index = 1; index < 8; index++) {
                        bufintr = ((intrstatus &
                                  (XUSB_STATUS_EP1_BUFF1_COMP_MASK <<
                                  (index - 1))) || (intrstatus &
                                  (XUSB_STATUS_EP1_BUFF2_COMP_MASK <<
                                  (index - 1))));
                        if (bufintr) {
                                xudc_nonctrl_ep_handler(udc, index,
                                                        intrstatus);
                        }
                }
        }

        spin_unlock_irqrestore(&udc->lock, flags);
        return IRQ_HANDLED;
}

/**
 * xudc_probe - The device probe function for driver initialization.
 * @pdev: pointer to the platform device structure.
 *
 * Return: 0 for success and error value on failure
 */
static int xudc_probe(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        struct resource *res;
        struct xusb_udc *udc;
        struct xusb_ep *ep0;
        int irq;
        int ret;
        u32 ier;
        u8 *buff;

        udc = devm_kzalloc(&pdev->dev, sizeof(*udc), GFP_KERNEL);
        if (!udc)
                return -ENOMEM;

        /* Create a dummy request for GET_STATUS, SET_ADDRESS */
        udc->req = devm_kzalloc(&pdev->dev, sizeof(struct xusb_req),
                                GFP_KERNEL);
        if (!udc->req)
                return -ENOMEM;

        buff = devm_kzalloc(&pdev->dev, STATUSBUFF_SIZE, GFP_KERNEL);
        if (!buff)
                return -ENOMEM;

        udc->req->usb_req.buf = buff;

        /* Map the registers */
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        udc->addr = devm_ioremap_resource(&pdev->dev, res);
        if (!udc->addr)
                return -ENOMEM;

        irq = platform_get_irq(pdev, 0);
        if (irq < 0) {
                dev_err(&pdev->dev, "unable to get irq\n");
                return irq;
        }
        ret = devm_request_irq(&pdev->dev, irq, xudc_irq, 0,
                               dev_name(&pdev->dev), udc);
        if (ret < 0) {
                dev_dbg(&pdev->dev, "unable to request irq %d", irq);
                goto fail;
        }

        udc->dma_enabled = of_property_read_bool(np, "xlnx,has-builtin-dma");

        /* Setup gadget structure */
        udc->gadget.ops = &xusb_udc_ops;
        udc->gadget.max_speed = USB_SPEED_HIGH;
        udc->gadget.speed = USB_SPEED_UNKNOWN;
        udc->gadget.ep0 = &udc->ep[XUSB_EP_NUMBER_ZERO].ep_usb;
        udc->gadget.name = driver_name;

        spin_lock_init(&udc->lock);

        /* Check for IP endianness */
        udc->write_fn = xudc_write32_be;
        udc->read_fn = xudc_read32_be;
        udc->write_fn(udc->addr, XUSB_TESTMODE_OFFSET, TEST_J);
        if ((udc->read_fn(udc->addr + XUSB_TESTMODE_OFFSET))
                        != TEST_J) {
                udc->write_fn = xudc_write32;
                udc->read_fn = xudc_read32;
        }
        udc->write_fn(udc->addr, XUSB_TESTMODE_OFFSET, 0);

        xudc_eps_init(udc);

        ep0 = &udc->ep[0];

        /* Set device address to 0.*/
        udc->write_fn(udc->addr, XUSB_ADDRESS_OFFSET, 0);

        ret = usb_add_gadget_udc(&pdev->dev, &udc->gadget);
        if (ret)
                goto fail;

        udc->dev = &udc->gadget.dev;

        /* Enable the interrupts.*/
        ier = XUSB_STATUS_GLOBAL_INTR_MASK | XUSB_STATUS_INTR_EVENT_MASK |
              XUSB_STATUS_FIFO_BUFF_RDY_MASK | XUSB_STATUS_FIFO_BUFF_FREE_MASK |
              XUSB_STATUS_SETUP_PACKET_MASK |
              XUSB_STATUS_INTR_BUFF_COMP_ALL_MASK;

        udc->write_fn(udc->addr, XUSB_IER_OFFSET, ier);

        platform_set_drvdata(pdev, udc);

        dev_vdbg(&pdev->dev, "%s at 0x%08X mapped to 0x%08X %s\n",
                 driver_name, (u32)res->start, (u32 __force)udc->addr,
                 udc->dma_enabled ? "with DMA" : "without DMA");

        return 0;
fail:
        dev_err(&pdev->dev, "probe failed, %d\n", ret);
        return ret;
}

/**
 * xudc_remove - Releases the resources allocated during the initialization.
 * @pdev: pointer to the platform device structure.
 *
 * Return: 0 always
 */
static int xudc_remove(struct platform_device *pdev)
{
        struct xusb_udc *udc = platform_get_drvdata(pdev);

        usb_del_gadget_udc(&udc->gadget);

        return 0;
}

/* Match table for of_platform binding */
static const struct of_device_id usb_of_match[] = {
        { .compatible = "xlnx,usb2-device-4.00.a", },
        { /* end of list */ },
};
MODULE_DEVICE_TABLE(of, usb_of_match);

static struct platform_driver xudc_driver = {
        .driver = {
                .name = driver_name,
                .of_match_table = usb_of_match,
        },
        .probe = xudc_probe,
        .remove = xudc_remove,
};

module_platform_driver(xudc_driver);

MODULE_DESCRIPTION("Xilinx udc driver");
MODULE_AUTHOR("Xilinx, Inc");
MODULE_LICENSE("GPL");