/*
 * Copyright (C) 2011 LAPIS Semiconductor Co., Ltd.
 *
 * 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; version 2 of the License.
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/list.h>
#include <linux/interrupt.h>
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>

/* Address offset of Registers */
#define UDC_EP_REG_SHIFT        0x20    /* Offset to next EP */

#define UDC_EPCTL_ADDR          0x00    /* Endpoint control */
#define UDC_EPSTS_ADDR          0x04    /* Endpoint status */
#define UDC_BUFIN_FRAMENUM_ADDR 0x08    /* buffer size in / frame number out */
#define UDC_BUFOUT_MAXPKT_ADDR  0x0C    /* buffer size out / maxpkt in */
#define UDC_SUBPTR_ADDR         0x10    /* setup buffer pointer */
#define UDC_DESPTR_ADDR         0x14    /* Data descriptor pointer */
#define UDC_CONFIRM_ADDR        0x18    /* Write/Read confirmation */

#define UDC_DEVCFG_ADDR         0x400   /* Device configuration */
#define UDC_DEVCTL_ADDR         0x404   /* Device control */
#define UDC_DEVSTS_ADDR         0x408   /* Device status */
#define UDC_DEVIRQSTS_ADDR      0x40C   /* Device irq status */
#define UDC_DEVIRQMSK_ADDR      0x410   /* Device irq mask */
#define UDC_EPIRQSTS_ADDR       0x414   /* Endpoint irq status */
#define UDC_EPIRQMSK_ADDR       0x418   /* Endpoint irq mask */
#define UDC_DEVLPM_ADDR         0x41C   /* LPM control / status */
#define UDC_CSR_BUSY_ADDR       0x4f0   /* UDC_CSR_BUSY Status register */
#define UDC_SRST_ADDR           0x4fc   /* SOFT RESET register */
#define UDC_CSR_ADDR            0x500   /* USB_DEVICE endpoint register */

/* Endpoint control register */
/* Bit position */
#define UDC_EPCTL_MRXFLUSH              (1 << 12)
#define UDC_EPCTL_RRDY                  (1 << 9)
#define UDC_EPCTL_CNAK                  (1 << 8)
#define UDC_EPCTL_SNAK                  (1 << 7)
#define UDC_EPCTL_NAK                   (1 << 6)
#define UDC_EPCTL_P                     (1 << 3)
#define UDC_EPCTL_F                     (1 << 1)
#define UDC_EPCTL_S                     (1 << 0)
#define UDC_EPCTL_ET_SHIFT              4
/* Mask patern */
#define UDC_EPCTL_ET_MASK               0x00000030
/* Value for ET field */
#define UDC_EPCTL_ET_CONTROL            0
#define UDC_EPCTL_ET_ISO                1
#define UDC_EPCTL_ET_BULK               2
#define UDC_EPCTL_ET_INTERRUPT          3

/* Endpoint status register */
/* Bit position */
#define UDC_EPSTS_XFERDONE              (1 << 27)
#define UDC_EPSTS_RSS                   (1 << 26)
#define UDC_EPSTS_RCS                   (1 << 25)
#define UDC_EPSTS_TXEMPTY               (1 << 24)
#define UDC_EPSTS_TDC                   (1 << 10)
#define UDC_EPSTS_HE                    (1 << 9)
#define UDC_EPSTS_MRXFIFO_EMP           (1 << 8)
#define UDC_EPSTS_BNA                   (1 << 7)
#define UDC_EPSTS_IN                    (1 << 6)
#define UDC_EPSTS_OUT_SHIFT             4
/* Mask patern */
#define UDC_EPSTS_OUT_MASK              0x00000030
#define UDC_EPSTS_ALL_CLR_MASK          0x1F0006F0
/* Value for OUT field */
#define UDC_EPSTS_OUT_SETUP             2
#define UDC_EPSTS_OUT_DATA              1

/* Device configuration register */
/* Bit position */
#define UDC_DEVCFG_CSR_PRG              (1 << 17)
#define UDC_DEVCFG_SP                   (1 << 3)
/* SPD Valee */
#define UDC_DEVCFG_SPD_HS               0x0
#define UDC_DEVCFG_SPD_FS               0x1
#define UDC_DEVCFG_SPD_LS               0x2

/* Device control register */
/* Bit position */
#define UDC_DEVCTL_THLEN_SHIFT          24
#define UDC_DEVCTL_BRLEN_SHIFT          16
#define UDC_DEVCTL_CSR_DONE             (1 << 13)
#define UDC_DEVCTL_SD                   (1 << 10)
#define UDC_DEVCTL_MODE                 (1 << 9)
#define UDC_DEVCTL_BREN                 (1 << 8)
#define UDC_DEVCTL_THE                  (1 << 7)
#define UDC_DEVCTL_DU                   (1 << 4)
#define UDC_DEVCTL_TDE                  (1 << 3)
#define UDC_DEVCTL_RDE                  (1 << 2)
#define UDC_DEVCTL_RES                  (1 << 0)

/* Device status register */
/* Bit position */
#define UDC_DEVSTS_TS_SHIFT             18
#define UDC_DEVSTS_ENUM_SPEED_SHIFT     13
#define UDC_DEVSTS_ALT_SHIFT            8
#define UDC_DEVSTS_INTF_SHIFT           4
#define UDC_DEVSTS_CFG_SHIFT            0
/* Mask patern */
#define UDC_DEVSTS_TS_MASK              0xfffc0000
#define UDC_DEVSTS_ENUM_SPEED_MASK      0x00006000
#define UDC_DEVSTS_ALT_MASK             0x00000f00
#define UDC_DEVSTS_INTF_MASK            0x000000f0
#define UDC_DEVSTS_CFG_MASK             0x0000000f
/* value for maximum speed for SPEED field */
#define UDC_DEVSTS_ENUM_SPEED_FULL      1
#define UDC_DEVSTS_ENUM_SPEED_HIGH      0
#define UDC_DEVSTS_ENUM_SPEED_LOW       2
#define UDC_DEVSTS_ENUM_SPEED_FULLX     3

/* Device irq register */
/* Bit position */
#define UDC_DEVINT_RWKP                 (1 << 7)
#define UDC_DEVINT_ENUM                 (1 << 6)
#define UDC_DEVINT_SOF                  (1 << 5)
#define UDC_DEVINT_US                   (1 << 4)
#define UDC_DEVINT_UR                   (1 << 3)
#define UDC_DEVINT_ES                   (1 << 2)
#define UDC_DEVINT_SI                   (1 << 1)
#define UDC_DEVINT_SC                   (1 << 0)
/* Mask patern */
#define UDC_DEVINT_MSK                  0x7f

/* Endpoint irq register */
/* Bit position */
#define UDC_EPINT_IN_SHIFT              0
#define UDC_EPINT_OUT_SHIFT             16
#define UDC_EPINT_IN_EP0                (1 << 0)
#define UDC_EPINT_OUT_EP0               (1 << 16)
/* Mask patern */
#define UDC_EPINT_MSK_DISABLE_ALL       0xffffffff

/* UDC_CSR_BUSY Status register */
/* Bit position */
#define UDC_CSR_BUSY                    (1 << 0)

/* SOFT RESET register */
/* Bit position */
#define UDC_PSRST                       (1 << 1)
#define UDC_SRST                        (1 << 0)

/* USB_DEVICE endpoint register */
/* Bit position */
#define UDC_CSR_NE_NUM_SHIFT            0
#define UDC_CSR_NE_DIR_SHIFT            4
#define UDC_CSR_NE_TYPE_SHIFT           5
#define UDC_CSR_NE_CFG_SHIFT            7
#define UDC_CSR_NE_INTF_SHIFT           11
#define UDC_CSR_NE_ALT_SHIFT            15
#define UDC_CSR_NE_MAX_PKT_SHIFT        19
/* Mask patern */
#define UDC_CSR_NE_NUM_MASK             0x0000000f
#define UDC_CSR_NE_DIR_MASK             0x00000010
#define UDC_CSR_NE_TYPE_MASK            0x00000060
#define UDC_CSR_NE_CFG_MASK             0x00000780
#define UDC_CSR_NE_INTF_MASK            0x00007800
#define UDC_CSR_NE_ALT_MASK             0x00078000
#define UDC_CSR_NE_MAX_PKT_MASK         0x3ff80000

#define PCH_UDC_CSR(ep) (UDC_CSR_ADDR + ep*4)
#define PCH_UDC_EPINT(in, num)\
                (1 << (num + (in ? UDC_EPINT_IN_SHIFT : UDC_EPINT_OUT_SHIFT)))

/* Index of endpoint */
#define UDC_EP0IN_IDX           0
#define UDC_EP0OUT_IDX          1
#define UDC_EPIN_IDX(ep)        (ep * 2)
#define UDC_EPOUT_IDX(ep)       (ep * 2 + 1)
#define PCH_UDC_EP0             0
#define PCH_UDC_EP1             1
#define PCH_UDC_EP2             2
#define PCH_UDC_EP3             3

/* Number of endpoint */
#define PCH_UDC_EP_NUM          32      /* Total number of EPs (16 IN,16 OUT) */
#define PCH_UDC_USED_EP_NUM     4       /* EP number of EP's really used */
/* Length Value */
#define PCH_UDC_BRLEN           0x0F    /* Burst length */
#define PCH_UDC_THLEN           0x1F    /* Threshold length */
/* Value of EP Buffer Size */
#define UDC_EP0IN_BUFF_SIZE     16
#define UDC_EPIN_BUFF_SIZE      256
#define UDC_EP0OUT_BUFF_SIZE    16
#define UDC_EPOUT_BUFF_SIZE     256
/* Value of EP maximum packet size */
#define UDC_EP0IN_MAX_PKT_SIZE  64
#define UDC_EP0OUT_MAX_PKT_SIZE 64
#define UDC_BULK_MAX_PKT_SIZE   512

/* DMA */
#define DMA_DIR_RX              1       /* DMA for data receive */
#define DMA_DIR_TX              2       /* DMA for data transmit */
#define DMA_ADDR_INVALID        (~(dma_addr_t)0)
#define UDC_DMA_MAXPACKET       65536   /* maximum packet size for DMA */

/**
 * struct pch_udc_data_dma_desc - Structure to hold DMA descriptor information
 *                                for data
 * @status:             Status quadlet
 * @reserved:           Reserved
 * @dataptr:            Buffer descriptor
 * @next:               Next descriptor
 */
struct pch_udc_data_dma_desc {
        u32 status;
        u32 reserved;
        u32 dataptr;
        u32 next;
};

/**
 * struct pch_udc_stp_dma_desc - Structure to hold DMA descriptor information
 *                               for control data
 * @status:     Status
 * @reserved:   Reserved
 * @data12:     First setup word
 * @data34:     Second setup word
 */
struct pch_udc_stp_dma_desc {
        u32 status;
        u32 reserved;
        struct usb_ctrlrequest request;
} __attribute((packed));

/* DMA status definitions */
/* Buffer status */
#define PCH_UDC_BUFF_STS        0xC0000000
#define PCH_UDC_BS_HST_RDY      0x00000000
#define PCH_UDC_BS_DMA_BSY      0x40000000
#define PCH_UDC_BS_DMA_DONE     0x80000000
#define PCH_UDC_BS_HST_BSY      0xC0000000
/*  Rx/Tx Status */
#define PCH_UDC_RXTX_STS        0x30000000
#define PCH_UDC_RTS_SUCC        0x00000000
#define PCH_UDC_RTS_DESERR      0x10000000
#define PCH_UDC_RTS_BUFERR      0x30000000
/* Last Descriptor Indication */
#define PCH_UDC_DMA_LAST        0x08000000
/* Number of Rx/Tx Bytes Mask */
#define PCH_UDC_RXTX_BYTES      0x0000ffff

/**
 * struct pch_udc_cfg_data - Structure to hold current configuration
 *                           and interface information
 * @cur_cfg:    current configuration in use
 * @cur_intf:   current interface in use
 * @cur_alt:    current alt interface in use
 */
struct pch_udc_cfg_data {
        u16 cur_cfg;
        u16 cur_intf;
        u16 cur_alt;
};

/**
 * struct pch_udc_ep - Structure holding a PCH USB device Endpoint information
 * @ep:                 embedded ep request
 * @td_stp_phys:        for setup request
 * @td_data_phys:       for data request
 * @td_stp:             for setup request
 * @td_data:            for data request
 * @dev:                reference to device struct
 * @offset_addr:        offset address of ep register
 * @desc:               for this ep
 * @queue:              queue for requests
 * @num:                endpoint number
 * @in:                 endpoint is IN
 * @halted:             endpoint halted?
 * @epsts:              Endpoint status
 */
struct pch_udc_ep {
        struct usb_ep                   ep;
        dma_addr_t                      td_stp_phys;
        dma_addr_t                      td_data_phys;
        struct pch_udc_stp_dma_desc     *td_stp;
        struct pch_udc_data_dma_desc    *td_data;
        struct pch_udc_dev              *dev;
        unsigned long                   offset_addr;
        const struct usb_endpoint_descriptor    *desc;
        struct list_head                queue;
        unsigned                        num:5,
                                        in:1,
                                        halted:1;
        unsigned long                   epsts;
};

/**
 * struct pch_udc_dev - Structure holding complete information
 *                      of the PCH USB device
 * @gadget:             gadget driver data
 * @driver:             reference to gadget driver bound
 * @pdev:               reference to the PCI device
 * @ep:                 array of endpoints
 * @lock:               protects all state
 * @active:             enabled the PCI device
 * @stall:              stall requested
 * @prot_stall:         protcol stall requested
 * @irq_registered:     irq registered with system
 * @mem_region:         device memory mapped
 * @registered:         driver regsitered with system
 * @suspended:          driver in suspended state
 * @connected:          gadget driver associated
 * @set_cfg_not_acked:  pending acknowledgement 4 setup
 * @waiting_zlp_ack:    pending acknowledgement 4 ZLP
 * @data_requests:      DMA pool for data requests
 * @stp_requests:       DMA pool for setup requests
 * @dma_addr:           DMA pool for received
 * @ep0out_buf:         Buffer for DMA
 * @setup_data:         Received setup data
 * @phys_addr:          of device memory
 * @base_addr:          for mapped device memory
 * @irq:                IRQ line for the device
 * @cfg_data:           current cfg, intf, and alt in use
 */
struct pch_udc_dev {
        struct usb_gadget               gadget;
        struct usb_gadget_driver        *driver;
        struct pci_dev                  *pdev;
        struct pch_udc_ep               ep[PCH_UDC_EP_NUM];
        spinlock_t                      lock; /* protects all state */
        unsigned        active:1,
                        stall:1,
                        prot_stall:1,
                        irq_registered:1,
                        mem_region:1,
                        registered:1,
                        suspended:1,
                        connected:1,
                        set_cfg_not_acked:1,
                        waiting_zlp_ack:1;
        struct pci_pool         *data_requests;
        struct pci_pool         *stp_requests;
        dma_addr_t                      dma_addr;
        void                            *ep0out_buf;
        struct usb_ctrlrequest          setup_data;
        unsigned long                   phys_addr;
        void __iomem                    *base_addr;
        unsigned                        irq;
        struct pch_udc_cfg_data cfg_data;
};

#define PCH_UDC_PCI_BAR                 1
#define PCI_DEVICE_ID_INTEL_EG20T_UDC   0x8808
#define PCI_VENDOR_ID_ROHM              0x10DB
#define PCI_DEVICE_ID_ML7213_IOH_UDC    0x801D
#define PCI_DEVICE_ID_ML7831_IOH_UDC    0x8808

static const char       ep0_string[] = "ep0in";
static DEFINE_SPINLOCK(udc_stall_spinlock);     /* stall spin lock */
struct pch_udc_dev *pch_udc;            /* pointer to device object */
static bool speed_fs;
module_param_named(speed_fs, speed_fs, bool, S_IRUGO);
MODULE_PARM_DESC(speed_fs, "true for Full speed operation");

/**
 * struct pch_udc_request - Structure holding a PCH USB device request packet
 * @req:                embedded ep request
 * @td_data_phys:       phys. address
 * @td_data:            first dma desc. of chain
 * @td_data_last:       last dma desc. of chain
 * @queue:              associated queue
 * @dma_going:          DMA in progress for request
 * @dma_mapped:         DMA memory mapped for request
 * @dma_done:           DMA completed for request
 * @chain_len:          chain length
 * @buf:                Buffer memory for align adjustment
 * @dma:                DMA memory for align adjustment
 */
struct pch_udc_request {
        struct usb_request              req;
        dma_addr_t                      td_data_phys;
        struct pch_udc_data_dma_desc    *td_data;
        struct pch_udc_data_dma_desc    *td_data_last;
        struct list_head                queue;
        unsigned                        dma_going:1,
                                        dma_mapped:1,
                                        dma_done:1;
        unsigned                        chain_len;
        void                            *buf;
        dma_addr_t                      dma;
};

static inline u32 pch_udc_readl(struct pch_udc_dev *dev, unsigned long reg)
{
        return ioread32(dev->base_addr + reg);
}

static inline void pch_udc_writel(struct pch_udc_dev *dev,
                                    unsigned long val, unsigned long reg)
{
        iowrite32(val, dev->base_addr + reg);
}

static inline void pch_udc_bit_set(struct pch_udc_dev *dev,
                                     unsigned long reg,
                                     unsigned long bitmask)
{
        pch_udc_writel(dev, pch_udc_readl(dev, reg) | bitmask, reg);
}

static inline void pch_udc_bit_clr(struct pch_udc_dev *dev,
                                     unsigned long reg,
                                     unsigned long bitmask)
{
        pch_udc_writel(dev, pch_udc_readl(dev, reg) & ~(bitmask), reg);
}

static inline u32 pch_udc_ep_readl(struct pch_udc_ep *ep, unsigned long reg)
{
        return ioread32(ep->dev->base_addr + ep->offset_addr + reg);
}

static inline void pch_udc_ep_writel(struct pch_udc_ep *ep,
                                    unsigned long val, unsigned long reg)
{
        iowrite32(val, ep->dev->base_addr + ep->offset_addr + reg);
}

static inline void pch_udc_ep_bit_set(struct pch_udc_ep *ep,
                                     unsigned long reg,
                                     unsigned long bitmask)
{
        pch_udc_ep_writel(ep, pch_udc_ep_readl(ep, reg) | bitmask, reg);
}

static inline void pch_udc_ep_bit_clr(struct pch_udc_ep *ep,
                                     unsigned long reg,
                                     unsigned long bitmask)
{
        pch_udc_ep_writel(ep, pch_udc_ep_readl(ep, reg) & ~(bitmask), reg);
}

/**
 * pch_udc_csr_busy() - Wait till idle.
 * @dev:        Reference to pch_udc_dev structure
 */
static void pch_udc_csr_busy(struct pch_udc_dev *dev)
{
        unsigned int count = 200;

        /* Wait till idle */
        while ((pch_udc_readl(dev, UDC_CSR_BUSY_ADDR) & UDC_CSR_BUSY)
                && --count)
                cpu_relax();
        if (!count)
                dev_err(&dev->pdev->dev, "%s: wait error\n", __func__);
}

/**
 * pch_udc_write_csr() - Write the command and status registers.
 * @dev:        Reference to pch_udc_dev structure
 * @val:        value to be written to CSR register
 * @addr:       address of CSR register
 */
static void pch_udc_write_csr(struct pch_udc_dev *dev, unsigned long val,
                               unsigned int ep)
{
        unsigned long reg = PCH_UDC_CSR(ep);

        pch_udc_csr_busy(dev);          /* Wait till idle */
        pch_udc_writel(dev, val, reg);
        pch_udc_csr_busy(dev);          /* Wait till idle */
}

/**
 * pch_udc_read_csr() - Read the command and status registers.
 * @dev:        Reference to pch_udc_dev structure
 * @addr:       address of CSR register
 *
 * Return codes:        content of CSR register
 */
static u32 pch_udc_read_csr(struct pch_udc_dev *dev, unsigned int ep)
{
        unsigned long reg = PCH_UDC_CSR(ep);

        pch_udc_csr_busy(dev);          /* Wait till idle */
        pch_udc_readl(dev, reg);        /* Dummy read */
        pch_udc_csr_busy(dev);          /* Wait till idle */
        return pch_udc_readl(dev, reg);
}

/**
 * pch_udc_rmt_wakeup() - Initiate for remote wakeup
 * @dev:        Reference to pch_udc_dev structure
 */
static inline void pch_udc_rmt_wakeup(struct pch_udc_dev *dev)
{
        pch_udc_bit_set(dev, UDC_DEVCTL_ADDR, UDC_DEVCTL_RES);
        mdelay(1);
        pch_udc_bit_clr(dev, UDC_DEVCTL_ADDR, UDC_DEVCTL_RES);
}

/**
 * pch_udc_get_frame() - Get the current frame from device status register
 * @dev:        Reference to pch_udc_dev structure
 * Retern       current frame
 */
static inline int pch_udc_get_frame(struct pch_udc_dev *dev)
{
        u32 frame = pch_udc_readl(dev, UDC_DEVSTS_ADDR);
        return (frame & UDC_DEVSTS_TS_MASK) >> UDC_DEVSTS_TS_SHIFT;
}

/**
 * pch_udc_clear_selfpowered() - Clear the self power control
 * @dev:        Reference to pch_udc_regs structure
 */
static inline void pch_udc_clear_selfpowered(struct pch_udc_dev *dev)
{
        pch_udc_bit_clr(dev, UDC_DEVCFG_ADDR, UDC_DEVCFG_SP);
}

/**
 * pch_udc_set_selfpowered() - Set the self power control
 * @dev:        Reference to pch_udc_regs structure
 */
static inline void pch_udc_set_selfpowered(struct pch_udc_dev *dev)
{
        pch_udc_bit_set(dev, UDC_DEVCFG_ADDR, UDC_DEVCFG_SP);
}

/**
 * pch_udc_set_disconnect() - Set the disconnect status.
 * @dev:        Reference to pch_udc_regs structure
 */
static inline void pch_udc_set_disconnect(struct pch_udc_dev *dev)
{
        pch_udc_bit_set(dev, UDC_DEVCTL_ADDR, UDC_DEVCTL_SD);
}

/**
 * pch_udc_clear_disconnect() - Clear the disconnect status.
 * @dev:        Reference to pch_udc_regs structure
 */
static void pch_udc_clear_disconnect(struct pch_udc_dev *dev)
{
        /* Clear the disconnect */
        pch_udc_bit_set(dev, UDC_DEVCTL_ADDR, UDC_DEVCTL_RES);
        pch_udc_bit_clr(dev, UDC_DEVCTL_ADDR, UDC_DEVCTL_SD);
        mdelay(1);
        /* Resume USB signalling */
        pch_udc_bit_clr(dev, UDC_DEVCTL_ADDR, UDC_DEVCTL_RES);
}

/**
 * pch_udc_vbus_session() - set or clearr the disconnect status.
 * @dev:        Reference to pch_udc_regs structure
 * @is_active:  Parameter specifying the action
 *                0:   indicating VBUS power is ending
 *                !0:  indicating VBUS power is starting
 */
static inline void pch_udc_vbus_session(struct pch_udc_dev *dev,
                                          int is_active)
{
        if (is_active)
                pch_udc_clear_disconnect(dev);
        else
                pch_udc_set_disconnect(dev);
}

/**
 * pch_udc_ep_set_stall() - Set the stall of endpoint
 * @ep:         Reference to structure of type pch_udc_ep_regs
 */
static void pch_udc_ep_set_stall(struct pch_udc_ep *ep)
{
        if (ep->in) {
                pch_udc_ep_bit_set(ep, UDC_EPCTL_ADDR, UDC_EPCTL_F);
                pch_udc_ep_bit_set(ep, UDC_EPCTL_ADDR, UDC_EPCTL_S);
        } else {
                pch_udc_ep_bit_set(ep, UDC_EPCTL_ADDR, UDC_EPCTL_S);
        }
}

/**
 * pch_udc_ep_clear_stall() - Clear the stall of endpoint
 * @ep:         Reference to structure of type pch_udc_ep_regs
 */
static inline void pch_udc_ep_clear_stall(struct pch_udc_ep *ep)
{
        /* Clear the stall */
        pch_udc_ep_bit_clr(ep, UDC_EPCTL_ADDR, UDC_EPCTL_S);
        /* Clear NAK by writing CNAK */
        pch_udc_ep_bit_set(ep, UDC_EPCTL_ADDR, UDC_EPCTL_CNAK);
}

/**
 * pch_udc_ep_set_trfr_type() - Set the transfer type of endpoint
 * @ep:         Reference to structure of type pch_udc_ep_regs
 * @type:       Type of endpoint
 */
static inline void pch_udc_ep_set_trfr_type(struct pch_udc_ep *ep,
                                        u8 type)
{
        pch_udc_ep_writel(ep, ((type << UDC_EPCTL_ET_SHIFT) &
                                UDC_EPCTL_ET_MASK), UDC_EPCTL_ADDR);
}

/**
 * pch_udc_ep_set_bufsz() - Set the maximum packet size for the endpoint
 * @ep:         Reference to structure of type pch_udc_ep_regs
 * @buf_size:   The buffer word size
 */
static void pch_udc_ep_set_bufsz(struct pch_udc_ep *ep,
                                                 u32 buf_size, u32 ep_in)
{
        u32 data;
        if (ep_in) {
                data = pch_udc_ep_readl(ep, UDC_BUFIN_FRAMENUM_ADDR);
                data = (data & 0xffff0000) | (buf_size & 0xffff);
                pch_udc_ep_writel(ep, data, UDC_BUFIN_FRAMENUM_ADDR);
        } else {
                data = pch_udc_ep_readl(ep, UDC_BUFOUT_MAXPKT_ADDR);
                data = (buf_size << 16) | (data & 0xffff);
                pch_udc_ep_writel(ep, data, UDC_BUFOUT_MAXPKT_ADDR);
        }
}

/**
 * pch_udc_ep_set_maxpkt() - Set the Max packet size for the endpoint
 * @ep:         Reference to structure of type pch_udc_ep_regs
 * @pkt_size:   The packet byte size
 */
static void pch_udc_ep_set_maxpkt(struct pch_udc_ep *ep, u32 pkt_size)
{
        u32 data = pch_udc_ep_readl(ep, UDC_BUFOUT_MAXPKT_ADDR);
        data = (data & 0xffff0000) | (pkt_size & 0xffff);
        pch_udc_ep_writel(ep, data, UDC_BUFOUT_MAXPKT_ADDR);
}

/**
 * pch_udc_ep_set_subptr() - Set the Setup buffer pointer for the endpoint
 * @ep:         Reference to structure of type pch_udc_ep_regs
 * @addr:       Address of the register
 */
static inline void pch_udc_ep_set_subptr(struct pch_udc_ep *ep, u32 addr)
{
        pch_udc_ep_writel(ep, addr, UDC_SUBPTR_ADDR);
}

/**
 * pch_udc_ep_set_ddptr() - Set the Data descriptor pointer for the endpoint
 * @ep:         Reference to structure of type pch_udc_ep_regs
 * @addr:       Address of the register
 */
static inline void pch_udc_ep_set_ddptr(struct pch_udc_ep *ep, u32 addr)
{
        pch_udc_ep_writel(ep, addr, UDC_DESPTR_ADDR);
}

/**
 * pch_udc_ep_set_pd() - Set the poll demand bit for the endpoint
 * @ep:         Reference to structure of type pch_udc_ep_regs
 */
static inline void pch_udc_ep_set_pd(struct pch_udc_ep *ep)
{
        pch_udc_ep_bit_set(ep, UDC_EPCTL_ADDR, UDC_EPCTL_P);
}

/**
 * pch_udc_ep_set_rrdy() - Set the receive ready bit for the endpoint
 * @ep:         Reference to structure of type pch_udc_ep_regs
 */
static inline void pch_udc_ep_set_rrdy(struct pch_udc_ep *ep)
{
        pch_udc_ep_bit_set(ep, UDC_EPCTL_ADDR, UDC_EPCTL_RRDY);
}

/**
 * pch_udc_ep_clear_rrdy() - Clear the receive ready bit for the endpoint
 * @ep:         Reference to structure of type pch_udc_ep_regs
 */
static inline void pch_udc_ep_clear_rrdy(struct pch_udc_ep *ep)
{
        pch_udc_ep_bit_clr(ep, UDC_EPCTL_ADDR, UDC_EPCTL_RRDY);
}

/**
 * pch_udc_set_dma() - Set the 'TDE' or RDE bit of device control
 *                      register depending on the direction specified
 * @dev:        Reference to structure of type pch_udc_regs
 * @dir:        whether Tx or Rx
 *                DMA_DIR_RX: Receive
 *                DMA_DIR_TX: Transmit
 */
static inline void pch_udc_set_dma(struct pch_udc_dev *dev, int dir)
{
        if (dir == DMA_DIR_RX)
                pch_udc_bit_set(dev, UDC_DEVCTL_ADDR, UDC_DEVCTL_RDE);
        else if (dir == DMA_DIR_TX)
                pch_udc_bit_set(dev, UDC_DEVCTL_ADDR, UDC_DEVCTL_TDE);
}

/**
 * pch_udc_clear_dma() - Clear the 'TDE' or RDE bit of device control
 *                               register depending on the direction specified
 * @dev:        Reference to structure of type pch_udc_regs
 * @dir:        Whether Tx or Rx
 *                DMA_DIR_RX: Receive
 *                DMA_DIR_TX: Transmit
 */
static inline void pch_udc_clear_dma(struct pch_udc_dev *dev, int dir)
{
        if (dir == DMA_DIR_RX)
                pch_udc_bit_clr(dev, UDC_DEVCTL_ADDR, UDC_DEVCTL_RDE);
        else if (dir == DMA_DIR_TX)
                pch_udc_bit_clr(dev, UDC_DEVCTL_ADDR, UDC_DEVCTL_TDE);
}

/**
 * pch_udc_set_csr_done() - Set the device control register
 *                              CSR done field (bit 13)
 * @dev:        reference to structure of type pch_udc_regs
 */
static inline void pch_udc_set_csr_done(struct pch_udc_dev *dev)
{
        pch_udc_bit_set(dev, UDC_DEVCTL_ADDR, UDC_DEVCTL_CSR_DONE);
}

/**
 * pch_udc_disable_interrupts() - Disables the specified interrupts
 * @dev:        Reference to structure of type pch_udc_regs
 * @mask:       Mask to disable interrupts
 */
static inline void pch_udc_disable_interrupts(struct pch_udc_dev *dev,
                                            u32 mask)
{
        pch_udc_bit_set(dev, UDC_DEVIRQMSK_ADDR, mask);
}

/**
 * pch_udc_enable_interrupts() - Enable the specified interrupts
 * @dev:        Reference to structure of type pch_udc_regs
 * @mask:       Mask to enable interrupts
 */
static inline void pch_udc_enable_interrupts(struct pch_udc_dev *dev,
                                           u32 mask)
{
        pch_udc_bit_clr(dev, UDC_DEVIRQMSK_ADDR, mask);
}

/**
 * pch_udc_disable_ep_interrupts() - Disable endpoint interrupts
 * @dev:        Reference to structure of type pch_udc_regs
 * @mask:       Mask to disable interrupts
 */
static inline void pch_udc_disable_ep_interrupts(struct pch_udc_dev *dev,
                                                u32 mask)
{
        pch_udc_bit_set(dev, UDC_EPIRQMSK_ADDR, mask);
}

/**
 * pch_udc_enable_ep_interrupts() - Enable endpoint interrupts
 * @dev:        Reference to structure of type pch_udc_regs
 * @mask:       Mask to enable interrupts
 */
static inline void pch_udc_enable_ep_interrupts(struct pch_udc_dev *dev,
                                              u32 mask)
{
        pch_udc_bit_clr(dev, UDC_EPIRQMSK_ADDR, mask);
}

/**
 * pch_udc_read_device_interrupts() - Read the device interrupts
 * @dev:        Reference to structure of type pch_udc_regs
 * Retern       The device interrupts
 */
static inline u32 pch_udc_read_device_interrupts(struct pch_udc_dev *dev)
{
        return pch_udc_readl(dev, UDC_DEVIRQSTS_ADDR);
}

/**
 * pch_udc_write_device_interrupts() - Write device interrupts
 * @dev:        Reference to structure of type pch_udc_regs
 * @val:        The value to be written to interrupt register
 */
static inline void pch_udc_write_device_interrupts(struct pch_udc_dev *dev,
                                                     u32 val)
{
        pch_udc_writel(dev, val, UDC_DEVIRQSTS_ADDR);
}

/**
 * pch_udc_read_ep_interrupts() - Read the endpoint interrupts
 * @dev:        Reference to structure of type pch_udc_regs
 * Retern       The endpoint interrupt
 */
static inline u32 pch_udc_read_ep_interrupts(struct pch_udc_dev *dev)
{
        return pch_udc_readl(dev, UDC_EPIRQSTS_ADDR);
}

/**
 * pch_udc_write_ep_interrupts() - Clear endpoint interupts
 * @dev:        Reference to structure of type pch_udc_regs
 * @val:        The value to be written to interrupt register
 */
static inline void pch_udc_write_ep_interrupts(struct pch_udc_dev *dev,
                                             u32 val)
{
        pch_udc_writel(dev, val, UDC_EPIRQSTS_ADDR);
}

/**
 * pch_udc_read_device_status() - Read the device status
 * @dev:        Reference to structure of type pch_udc_regs
 * Retern       The device status
 */
static inline u32 pch_udc_read_device_status(struct pch_udc_dev *dev)
{
        return pch_udc_readl(dev, UDC_DEVSTS_ADDR);
}

/**
 * pch_udc_read_ep_control() - Read the endpoint control
 * @ep:         Reference to structure of type pch_udc_ep_regs
 * Retern       The endpoint control register value
 */
static inline u32 pch_udc_read_ep_control(struct pch_udc_ep *ep)
{
        return pch_udc_ep_readl(ep, UDC_EPCTL_ADDR);
}

/**
 * pch_udc_clear_ep_control() - Clear the endpoint control register
 * @ep:         Reference to structure of type pch_udc_ep_regs
 * Retern       The endpoint control register value
 */
static inline void pch_udc_clear_ep_control(struct pch_udc_ep *ep)
{
        return pch_udc_ep_writel(ep, 0, UDC_EPCTL_ADDR);
}

/**
 * pch_udc_read_ep_status() - Read the endpoint status
 * @ep:         Reference to structure of type pch_udc_ep_regs
 * Retern       The endpoint status
 */
static inline u32 pch_udc_read_ep_status(struct pch_udc_ep *ep)
{
        return pch_udc_ep_readl(ep, UDC_EPSTS_ADDR);
}

/**
 * pch_udc_clear_ep_status() - Clear the endpoint status
 * @ep:         Reference to structure of type pch_udc_ep_regs
 * @stat:       Endpoint status
 */
static inline void pch_udc_clear_ep_status(struct pch_udc_ep *ep,
                                         u32 stat)
{
        return pch_udc_ep_writel(ep, stat, UDC_EPSTS_ADDR);
}

/**
 * pch_udc_ep_set_nak() - Set the bit 7 (SNAK field)
 *                              of the endpoint control register
 * @ep:         Reference to structure of type pch_udc_ep_regs
 */
static inline void pch_udc_ep_set_nak(struct pch_udc_ep *ep)
{
        pch_udc_ep_bit_set(ep, UDC_EPCTL_ADDR, UDC_EPCTL_SNAK);
}

/**
 * pch_udc_ep_clear_nak() - Set the bit 8 (CNAK field)
 *                              of the endpoint control register
 * @ep:         reference to structure of type pch_udc_ep_regs
 */
static void pch_udc_ep_clear_nak(struct pch_udc_ep *ep)
{
        unsigned int loopcnt = 0;
        struct pch_udc_dev *dev = ep->dev;

        if (!(pch_udc_ep_readl(ep, UDC_EPCTL_ADDR) & UDC_EPCTL_NAK))
                return;
        if (!ep->in) {
                loopcnt = 10000;
                while (!(pch_udc_read_ep_status(ep) & UDC_EPSTS_MRXFIFO_EMP) &&
                        --loopcnt)
                        udelay(5);
                if (!loopcnt)
                        dev_err(&dev->pdev->dev, "%s: RxFIFO not Empty\n",
                                __func__);
        }
        loopcnt = 10000;
        while ((pch_udc_read_ep_control(ep) & UDC_EPCTL_NAK) && --loopcnt) {
                pch_udc_ep_bit_set(ep, UDC_EPCTL_ADDR, UDC_EPCTL_CNAK);
                udelay(5);
        }
        if (!loopcnt)
                dev_err(&dev->pdev->dev, "%s: Clear NAK not set for ep%d%s\n",
                        __func__, ep->num, (ep->in ? "in" : "out"));
}

/**
 * pch_udc_ep_fifo_flush() - Flush the endpoint fifo
 * @ep: reference to structure of type pch_udc_ep_regs
 * @dir:        direction of endpoint
 *                0:  endpoint is OUT
 *                !0: endpoint is IN
 */
static void pch_udc_ep_fifo_flush(struct pch_udc_ep *ep, int dir)
{
        if (dir) {      /* IN ep */
                pch_udc_ep_bit_set(ep, UDC_EPCTL_ADDR, UDC_EPCTL_F);
                return;
        }
}

/**
 * pch_udc_ep_enable() - This api enables endpoint
 * @regs:       Reference to structure pch_udc_ep_regs
 * @desc:       endpoint descriptor
 */
static void pch_udc_ep_enable(struct pch_udc_ep *ep,
                               struct pch_udc_cfg_data *cfg,
                               const struct usb_endpoint_descriptor *desc)
{
        u32 val = 0;
        u32 buff_size = 0;

        pch_udc_ep_set_trfr_type(ep, desc->bmAttributes);
        if (ep->in)
                buff_size = UDC_EPIN_BUFF_SIZE;
        else
                buff_size = UDC_EPOUT_BUFF_SIZE;
        pch_udc_ep_set_bufsz(ep, buff_size, ep->in);
        pch_udc_ep_set_maxpkt(ep, usb_endpoint_maxp(desc));
        pch_udc_ep_set_nak(ep);
        pch_udc_ep_fifo_flush(ep, ep->in);
        /* Configure the endpoint */
        val = ep->num << UDC_CSR_NE_NUM_SHIFT | ep->in << UDC_CSR_NE_DIR_SHIFT |
              ((desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) <<
                UDC_CSR_NE_TYPE_SHIFT) |
              (cfg->cur_cfg << UDC_CSR_NE_CFG_SHIFT) |
              (cfg->cur_intf << UDC_CSR_NE_INTF_SHIFT) |
              (cfg->cur_alt << UDC_CSR_NE_ALT_SHIFT) |
              usb_endpoint_maxp(desc) << UDC_CSR_NE_MAX_PKT_SHIFT;

        if (ep->in)
                pch_udc_write_csr(ep->dev, val, UDC_EPIN_IDX(ep->num));
        else
                pch_udc_write_csr(ep->dev, val, UDC_EPOUT_IDX(ep->num));
}

/**
 * pch_udc_ep_disable() - This api disables endpoint
 * @regs:       Reference to structure pch_udc_ep_regs
 */
static void pch_udc_ep_disable(struct pch_udc_ep *ep)
{
        if (ep->in) {
                /* flush the fifo */
                pch_udc_ep_writel(ep, UDC_EPCTL_F, UDC_EPCTL_ADDR);
                /* set NAK */
                pch_udc_ep_writel(ep, UDC_EPCTL_SNAK, UDC_EPCTL_ADDR);
                pch_udc_ep_bit_set(ep, UDC_EPSTS_ADDR, UDC_EPSTS_IN);
        } else {
                /* set NAK */
                pch_udc_ep_writel(ep, UDC_EPCTL_SNAK, UDC_EPCTL_ADDR);
        }
        /* reset desc pointer */
        pch_udc_ep_writel(ep, 0, UDC_DESPTR_ADDR);
}

/**
 * pch_udc_wait_ep_stall() - Wait EP stall.
 * @dev:        Reference to pch_udc_dev structure
 */
static void pch_udc_wait_ep_stall(struct pch_udc_ep *ep)
{
        unsigned int count = 10000;

        /* Wait till idle */
        while ((pch_udc_read_ep_control(ep) & UDC_EPCTL_S) && --count)
                udelay(5);
        if (!count)
                dev_err(&ep->dev->pdev->dev, "%s: wait error\n", __func__);
}

/**
 * pch_udc_init() - This API initializes usb device controller
 * @dev:        Rreference to pch_udc_regs structure
 */
static void pch_udc_init(struct pch_udc_dev *dev)
{

        if (NULL == dev) {
                pr_err("%s: Invalid address\n", __func__);
                return;
        }
        /* Soft Reset and Reset PHY */
        pch_udc_writel(dev, UDC_SRST, UDC_SRST_ADDR);
        pch_udc_writel(dev, UDC_SRST | UDC_PSRST, UDC_SRST_ADDR);
        mdelay(1);
        pch_udc_writel(dev, UDC_SRST, UDC_SRST_ADDR);
        pch_udc_writel(dev, 0x00, UDC_SRST_ADDR);
        mdelay(1);
        /* mask and clear all device interrupts */
        pch_udc_bit_set(dev, UDC_DEVIRQMSK_ADDR, UDC_DEVINT_MSK);
        pch_udc_bit_set(dev, UDC_DEVIRQSTS_ADDR, UDC_DEVINT_MSK);

        /* mask and clear all ep interrupts */
        pch_udc_bit_set(dev, UDC_EPIRQMSK_ADDR, UDC_EPINT_MSK_DISABLE_ALL);
        pch_udc_bit_set(dev, UDC_EPIRQSTS_ADDR, UDC_EPINT_MSK_DISABLE_ALL);

        /* enable dynamic CSR programmingi, self powered and device speed */
        if (speed_fs)
                pch_udc_bit_set(dev, UDC_DEVCFG_ADDR, UDC_DEVCFG_CSR_PRG |
                                UDC_DEVCFG_SP | UDC_DEVCFG_SPD_FS);
        else /* defaul high speed */
                pch_udc_bit_set(dev, UDC_DEVCFG_ADDR, UDC_DEVCFG_CSR_PRG |
                                UDC_DEVCFG_SP | UDC_DEVCFG_SPD_HS);
        pch_udc_bit_set(dev, UDC_DEVCTL_ADDR,
                        (PCH_UDC_THLEN << UDC_DEVCTL_THLEN_SHIFT) |
                        (PCH_UDC_BRLEN << UDC_DEVCTL_BRLEN_SHIFT) |
                        UDC_DEVCTL_MODE | UDC_DEVCTL_BREN |
                        UDC_DEVCTL_THE);
}

/**
 * pch_udc_exit() - This API exit usb device controller
 * @dev:        Reference to pch_udc_regs structure
 */
static void pch_udc_exit(struct pch_udc_dev *dev)
{
        /* mask all device interrupts */
        pch_udc_bit_set(dev, UDC_DEVIRQMSK_ADDR, UDC_DEVINT_MSK);
        /* mask all ep interrupts */
        pch_udc_bit_set(dev, UDC_EPIRQMSK_ADDR, UDC_EPINT_MSK_DISABLE_ALL);
        /* put device in disconnected state */
        pch_udc_set_disconnect(dev);
}

/**
 * pch_udc_pcd_get_frame() - This API is invoked to get the current frame number
 * @gadget:     Reference to the gadget driver
 *
 * Return codes:
 *      0:              Success
 *      -EINVAL:        If the gadget passed is NULL
 */
static int pch_udc_pcd_get_frame(struct usb_gadget *gadget)
{
        struct pch_udc_dev      *dev;

        if (!gadget)
                return -EINVAL;
        dev = container_of(gadget, struct pch_udc_dev, gadget);
        return pch_udc_get_frame(dev);
}

/**
 * pch_udc_pcd_wakeup() - This API is invoked to initiate a remote wakeup
 * @gadget:     Reference to the gadget driver
 *
 * Return codes:
 *      0:              Success
 *      -EINVAL:        If the gadget passed is NULL
 */
static int pch_udc_pcd_wakeup(struct usb_gadget *gadget)
{
        struct pch_udc_dev      *dev;
        unsigned long           flags;

        if (!gadget)
                return -EINVAL;
        dev = container_of(gadget, struct pch_udc_dev, gadget);
        spin_lock_irqsave(&dev->lock, flags);
        pch_udc_rmt_wakeup(dev);
        spin_unlock_irqrestore(&dev->lock, flags);
        return 0;
}

/**
 * pch_udc_pcd_selfpowered() - This API is invoked to specify whether the device
 *                              is self powered or not
 * @gadget:     Reference to the gadget driver
 * @value:      Specifies self powered or not
 *
 * Return codes:
 *      0:              Success
 *      -EINVAL:        If the gadget passed is NULL
 */
static int pch_udc_pcd_selfpowered(struct usb_gadget *gadget, int value)
{
        struct pch_udc_dev      *dev;

        if (!gadget)
                return -EINVAL;
        dev = container_of(gadget, struct pch_udc_dev, gadget);
        if (value)
                pch_udc_set_selfpowered(dev);
        else
                pch_udc_clear_selfpowered(dev);
        return 0;
}

/**
 * pch_udc_pcd_pullup() - This API is invoked to make the device
 *                              visible/invisible to the host
 * @gadget:     Reference to the gadget driver
 * @is_on:      Specifies whether the pull up is made active or inactive
 *
 * Return codes:
 *      0:              Success
 *      -EINVAL:        If the gadget passed is NULL
 */
static int pch_udc_pcd_pullup(struct usb_gadget *gadget, int is_on)
{
        struct pch_udc_dev      *dev;

        if (!gadget)
                return -EINVAL;
        dev = container_of(gadget, struct pch_udc_dev, gadget);
        pch_udc_vbus_session(dev, is_on);
        return 0;
}

/**
 * pch_udc_pcd_vbus_session() - This API is used by a driver for an external
 *                              transceiver (or GPIO) that
 *                              detects a VBUS power session starting/ending
 * @gadget:     Reference to the gadget driver
 * @is_active:  specifies whether the session is starting or ending
 *
 * Return codes:
 *      0:              Success
 *      -EINVAL:        If the gadget passed is NULL
 */
static int pch_udc_pcd_vbus_session(struct usb_gadget *gadget, int is_active)
{
        struct pch_udc_dev      *dev;

        if (!gadget)
                return -EINVAL;
        dev = container_of(gadget, struct pch_udc_dev, gadget);
        pch_udc_vbus_session(dev, is_active);
        return 0;
}

/**
 * pch_udc_pcd_vbus_draw() - This API is used by gadget drivers during
 *                              SET_CONFIGURATION calls to
 *                              specify how much power the device can consume
 * @gadget:     Reference to the gadget driver
 * @mA:         specifies the current limit in 2mA unit
 *
 * Return codes:
 *      -EINVAL:        If the gadget passed is NULL
 *      -EOPNOTSUPP:
 */
static int pch_udc_pcd_vbus_draw(struct usb_gadget *gadget, unsigned int mA)
{
        return -EOPNOTSUPP;
}

static int pch_udc_start(struct usb_gadget_driver *driver,
        int (*bind)(struct usb_gadget *));
static int pch_udc_stop(struct usb_gadget_driver *driver);
static const struct usb_gadget_ops pch_udc_ops = {
        .get_frame = pch_udc_pcd_get_frame,
        .wakeup = pch_udc_pcd_wakeup,
        .set_selfpowered = pch_udc_pcd_selfpowered,
        .pullup = pch_udc_pcd_pullup,
        .vbus_session = pch_udc_pcd_vbus_session,
        .vbus_draw = pch_udc_pcd_vbus_draw,
        .start  = pch_udc_start,
        .stop   = pch_udc_stop,
};

/**
 * complete_req() - This API is invoked from the driver when processing
 *                      of a request is complete
 * @ep:         Reference to the endpoint structure
 * @req:        Reference to the request structure
 * @status:     Indicates the success/failure of completion
 */
static void complete_req(struct pch_udc_ep *ep, struct pch_udc_request *req,
                                                                 int status)
{
        struct pch_udc_dev      *dev;
        unsigned halted = ep->halted;

        list_del_init(&req->queue);

        /* set new status if pending */
        if (req->req.status == -EINPROGRESS)
                req->req.status = status;
        else
                status = req->req.status;

        dev = ep->dev;
        if (req->dma_mapped) {
                if (req->dma == DMA_ADDR_INVALID) {
                        if (ep->in)
                                dma_unmap_single(&dev->pdev->dev, req->req.dma,
                                                 req->req.length,
                                                 DMA_TO_DEVICE);
                        else
                                dma_unmap_single(&dev->pdev->dev, req->req.dma,
                                                 req->req.length,
                                                 DMA_FROM_DEVICE);
                        req->req.dma = DMA_ADDR_INVALID;
                } else {
                        if (ep->in)
                                dma_unmap_single(&dev->pdev->dev, req->dma,
                                                 req->req.length,
                                                 DMA_TO_DEVICE);
                        else {
                                dma_unmap_single(&dev->pdev->dev, req->dma,
                                                 req->req.length,
                                                 DMA_FROM_DEVICE);
                                memcpy(req->req.buf, req->buf, req->req.length);
                        }
                        kfree(req->buf);
                        req->dma = DMA_ADDR_INVALID;
                }
                req->dma_mapped = 0;
        }
        ep->halted = 1;
        spin_unlock(&dev->lock);
        if (!ep->in)
                pch_udc_ep_clear_rrdy(ep);
        req->req.complete(&ep->ep, &req->req);
        spin_lock(&dev->lock);
        ep->halted = halted;
}

/**
 * empty_req_queue() - This API empties the request queue of an endpoint
 * @ep:         Reference to the endpoint structure
 */
static void empty_req_queue(struct pch_udc_ep *ep)
{
        struct pch_udc_request  *req;

        ep->halted = 1;
        while (!list_empty(&ep->queue)) {
                req = list_entry(ep->queue.next, struct pch_udc_request, queue);
                complete_req(ep, req, -ESHUTDOWN);      /* Remove from list */
        }
}

/**
 * pch_udc_free_dma_chain() - This function frees the DMA chain created
 *                              for the request
 * @dev         Reference to the driver structure
 * @req         Reference to the request to be freed
 *
 * Return codes:
 *      0: Success
 */
static void pch_udc_free_dma_chain(struct pch_udc_dev *dev,
                                   struct pch_udc_request *req)
{
        struct pch_udc_data_dma_desc *td = req->td_data;
        unsigned i = req->chain_len;

        dma_addr_t addr2;
        dma_addr_t addr = (dma_addr_t)td->next;
        td->next = 0x00;
        for (; i > 1; --i) {
                /* do not free first desc., will be done by free for request */
                td = phys_to_virt(addr);
                addr2 = (dma_addr_t)td->next;
                pci_pool_free(dev->data_requests, td, addr);
                td->next = 0x00;
                addr = addr2;
        }
        req->chain_len = 1;
}

/**
 * pch_udc_create_dma_chain() - This function creates or reinitializes
 *                              a DMA chain
 * @ep:         Reference to the endpoint structure
 * @req:        Reference to the request
 * @buf_len:    The buffer length
 * @gfp_flags:  Flags to be used while mapping the data buffer
 *
 * Return codes:
 *      0:              success,
 *      -ENOMEM:        pci_pool_alloc invocation fails
 */
static int pch_udc_create_dma_chain(struct pch_udc_ep *ep,
                                    struct pch_udc_request *req,
                                    unsigned long buf_len,
                                    gfp_t gfp_flags)
{
        struct pch_udc_data_dma_desc *td = req->td_data, *last;
        unsigned long bytes = req->req.length, i = 0;
        dma_addr_t dma_addr;
        unsigned len = 1;

        if (req->chain_len > 1)
                pch_udc_free_dma_chain(ep->dev, req);

        if (req->dma == DMA_ADDR_INVALID)
                td->dataptr = req->req.dma;
        else
                td->dataptr = req->dma;

        td->status = PCH_UDC_BS_HST_BSY;
        for (; ; bytes -= buf_len, ++len) {
                td->status = PCH_UDC_BS_HST_BSY | min(buf_len, bytes);
                if (bytes <= buf_len)
                        break;
                last = td;
                td = pci_pool_alloc(ep->dev->data_requests, gfp_flags,
                                    &dma_addr);
                if (!td)
                        goto nomem;
                i += buf_len;
                td->dataptr = req->td_data->dataptr + i;
                last->next = dma_addr;
        }

        req->td_data_last = td;
        td->status |= PCH_UDC_DMA_LAST;
        td->next = req->td_data_phys;
        req->chain_len = len;
        return 0;

nomem:
        if (len > 1) {
                req->chain_len = len;
                pch_udc_free_dma_chain(ep->dev, req);
        }
        req->chain_len = 1;
        return -ENOMEM;
}

/**
 * prepare_dma() - This function creates and initializes the DMA chain
 *                      for the request
 * @ep:         Reference to the endpoint structure
 * @req:        Reference to the request
 * @gfp:        Flag to be used while mapping the data buffer
 *
 * Return codes:
 *      0:              Success
 *      Other 0:        linux error number on failure
 */
static int prepare_dma(struct pch_udc_ep *ep, struct pch_udc_request *req,
                          gfp_t gfp)
{
        int     retval;

        /* Allocate and create a DMA chain */
        retval = pch_udc_create_dma_chain(ep, req, ep->ep.maxpacket, gfp);
        if (retval) {
                pr_err("%s: could not create DMA chain:%d\n", __func__, retval);
                return retval;
        }
        if (ep->in)
                req->td_data->status = (req->td_data->status &
                                ~PCH_UDC_BUFF_STS) | PCH_UDC_BS_HST_RDY;
        return 0;
}

/**
 * process_zlp() - This function process zero length packets
 *                      from the gadget driver
 * @ep:         Reference to the endpoint structure
 * @req:        Reference to the request
 */
static void process_zlp(struct pch_udc_ep *ep, struct pch_udc_request *req)
{
        struct pch_udc_dev      *dev = ep->dev;

        /* IN zlp's are handled by hardware */
        complete_req(ep, req, 0);

        /* if set_config or set_intf is waiting for ack by zlp
         * then set CSR_DONE
         */
        if (dev->set_cfg_not_acked) {
                pch_udc_set_csr_done(dev);
                dev->set_cfg_not_acked = 0;
        }
        /* setup command is ACK'ed now by zlp */
        if (!dev->stall && dev->waiting_zlp_ack) {
                pch_udc_ep_clear_nak(&(dev->ep[UDC_EP0IN_IDX]));
                dev->waiting_zlp_ack = 0;
        }
}

/**
 * pch_udc_start_rxrequest() - This function starts the receive requirement.
 * @ep:         Reference to the endpoint structure
 * @req:        Reference to the request structure
 */
static void pch_udc_start_rxrequest(struct pch_udc_ep *ep,
                                         struct pch_udc_request *req)
{
        struct pch_udc_data_dma_desc *td_data;

        pch_udc_clear_dma(ep->dev, DMA_DIR_RX);
        td_data = req->td_data;
        /* Set the status bits for all descriptors */
        while (1) {
                td_data->status = (td_data->status & ~PCH_UDC_BUFF_STS) |
                                    PCH_UDC_BS_HST_RDY;
                if ((td_data->status & PCH_UDC_DMA_LAST) ==  PCH_UDC_DMA_LAST)
                        break;
                td_data = phys_to_virt(td_data->next);
        }
        /* Write the descriptor pointer */
        pch_udc_ep_set_ddptr(ep, req->td_data_phys);
        req->dma_going = 1;
        pch_udc_enable_ep_interrupts(ep->dev, UDC_EPINT_OUT_EP0 << ep->num);
        pch_udc_set_dma(ep->dev, DMA_DIR_RX);
        pch_udc_ep_clear_nak(ep);
        pch_udc_ep_set_rrdy(ep);
}

/**
 * pch_udc_pcd_ep_enable() - This API enables the endpoint. It is called
 *                              from gadget driver
 * @usbep:      Reference to the USB endpoint structure
 * @desc:       Reference to the USB endpoint descriptor structure
 *
 * Return codes:
 *      0:              Success
 *      -EINVAL:
 *      -ESHUTDOWN:
 */
static int pch_udc_pcd_ep_enable(struct usb_ep *usbep,
                                    const struct usb_endpoint_descriptor *desc)
{
        struct pch_udc_ep       *ep;
        struct pch_udc_dev      *dev;
        unsigned long           iflags;

        if (!usbep || (usbep->name == ep0_string) || !desc ||
            (desc->bDescriptorType != USB_DT_ENDPOINT) || !desc->wMaxPacketSize)
                return -EINVAL;

        ep = container_of(usbep, struct pch_udc_ep, ep);
        dev = ep->dev;
        if (!dev->driver || (dev->gadget.speed == USB_SPEED_UNKNOWN))
                return -ESHUTDOWN;
        spin_lock_irqsave(&dev->lock, iflags);
        ep->desc = desc;
        ep->halted = 0;
        pch_udc_ep_enable(ep, &ep->dev->cfg_data, desc);
        ep->ep.maxpacket = usb_endpoint_maxp(desc);
        pch_udc_enable_ep_interrupts(ep->dev, PCH_UDC_EPINT(ep->in, ep->num));
        spin_unlock_irqrestore(&dev->lock, iflags);
        return 0;
}

/**
 * pch_udc_pcd_ep_disable() - This API disables endpoint and is called
 *                              from gadget driver
 * @usbep       Reference to the USB endpoint structure
 *
 * Return codes:
 *      0:              Success
 *      -EINVAL:
 */
static int pch_udc_pcd_ep_disable(struct usb_ep *usbep)
{
        struct pch_udc_ep       *ep;
        struct pch_udc_dev      *dev;
        unsigned long   iflags;

        if (!usbep)
                return -EINVAL;

        ep = container_of(usbep, struct pch_udc_ep, ep);
        dev = ep->dev;
        if ((usbep->name == ep0_string) || !ep->desc)
                return -EINVAL;

        spin_lock_irqsave(&ep->dev->lock, iflags);
        empty_req_queue(ep);
        ep->halted = 1;
        pch_udc_ep_disable(ep);
        pch_udc_disable_ep_interrupts(ep->dev, PCH_UDC_EPINT(ep->in, ep->num));
        ep->desc = NULL;
        ep->ep.desc = NULL;
        INIT_LIST_HEAD(&ep->queue);
        spin_unlock_irqrestore(&ep->dev->lock, iflags);
        return 0;
}

/**
 * pch_udc_alloc_request() - This function allocates request structure.
 *                              It is called by gadget driver
 * @usbep:      Reference to the USB endpoint structure
 * @gfp:        Flag to be used while allocating memory
 *
 * Return codes:
 *      NULL:                   Failure
 *      Allocated address:      Success
 */
static struct usb_request *pch_udc_alloc_request(struct usb_ep *usbep,
                                                  gfp_t gfp)
{
        struct pch_udc_request          *req;
        struct pch_udc_ep               *ep;
        struct pch_udc_data_dma_desc    *dma_desc;
        struct pch_udc_dev              *dev;

        if (!usbep)
                return NULL;
        ep = container_of(usbep, struct pch_udc_ep, ep);
        dev = ep->dev;
        req = kzalloc(sizeof *req, gfp);
        if (!req)
                return NULL;
        req->req.dma = DMA_ADDR_INVALID;
        req->dma = DMA_ADDR_INVALID;
        INIT_LIST_HEAD(&req->queue);
        if (!ep->dev->dma_addr)
                return &req->req;
        /* ep0 in requests are allocated from data pool here */
        dma_desc = pci_pool_alloc(ep->dev->data_requests, gfp,
                                  &req->td_data_phys);
        if (NULL == dma_desc) {
                kfree(req);
                return NULL;
        }
        /* prevent from using desc. - set HOST BUSY */
        dma_desc->status |= PCH_UDC_BS_HST_BSY;
        dma_desc->dataptr = __constant_cpu_to_le32(DMA_ADDR_INVALID);
        req->td_data = dma_desc;
        req->td_data_last = dma_desc;
        req->chain_len = 1;
        return &req->req;
}

/**
 * pch_udc_free_request() - This function frees request structure.
 *                              It is called by gadget driver
 * @usbep:      Reference to the USB endpoint structure
 * @usbreq:     Reference to the USB request
 */
static void pch_udc_free_request(struct usb_ep *usbep,
                                  struct usb_request *usbreq)
{
        struct pch_udc_ep       *ep;
        struct pch_udc_request  *req;
        struct pch_udc_dev      *dev;

        if (!usbep || !usbreq)
                return;
        ep = container_of(usbep, struct pch_udc_ep, ep);
        req = container_of(usbreq, struct pch_udc_request, req);
        dev = ep->dev;
        if (!list_empty(&req->queue))
                dev_err(&dev->pdev->dev, "%s: %s req=0x%p queue not empty\n",
                        __func__, usbep->name, req);
        if (req->td_data != NULL) {
                if (req->chain_len > 1)
                        pch_udc_free_dma_chain(ep->dev, req);
                pci_pool_free(ep->dev->data_requests, req->td_data,
                              req->td_data_phys);
        }
        kfree(req);
}

/**
 * pch_udc_pcd_queue() - This function queues a request packet. It is called
 *                      by gadget driver
 * @usbep:      Reference to the USB endpoint structure
 * @usbreq:     Reference to the USB request
 * @gfp:        Flag to be used while mapping the data buffer
 *
 * Return codes:
 *      0:                      Success
 *      linux error number:     Failure
 */
static int pch_udc_pcd_queue(struct usb_ep *usbep, struct usb_request *usbreq,
                                                                 gfp_t gfp)
{
        int retval = 0;
        struct pch_udc_ep       *ep;
        struct pch_udc_dev      *dev;
        struct pch_udc_request  *req;
        unsigned long   iflags;

        if (!usbep || !usbreq || !usbreq->complete || !usbreq->buf)
                return -EINVAL;
        ep = container_of(usbep, struct pch_udc_ep, ep);
        dev = ep->dev;
        if (!ep->desc && ep->num)
                return -EINVAL;
        req = container_of(usbreq, struct pch_udc_request, req);
        if (!list_empty(&req->queue))
                return -EINVAL;
        if (!dev->driver || (dev->gadget.speed == USB_SPEED_UNKNOWN))
                return -ESHUTDOWN;
        spin_lock_irqsave(&dev->lock, iflags);
        /* map the buffer for dma */
        if (usbreq->length &&
            ((usbreq->dma == DMA_ADDR_INVALID) || !usbreq->dma)) {
                if (!((unsigned long)(usbreq->buf) & 0x03)) {
                        if (ep->in)
                                usbreq->dma = dma_map_single(&dev->pdev->dev,
                                                             usbreq->buf,
                                                             usbreq->length,
                                                             DMA_TO_DEVICE);
                        else
                                usbreq->dma = dma_map_single(&dev->pdev->dev,
                                                             usbreq->buf,
                                                             usbreq->length,
                                                             DMA_FROM_DEVICE);
                } else {
                        req->buf = kzalloc(usbreq->length, GFP_ATOMIC);
                        if (!req->buf) {
                                retval = -ENOMEM;
                                goto probe_end;
                        }
                        if (ep->in) {
                                memcpy(req->buf, usbreq->buf, usbreq->length);
                                req->dma = dma_map_single(&dev->pdev->dev,
                                                          req->buf,
                                                          usbreq->length,
                                                          DMA_TO_DEVICE);
                        } else
                                req->dma = dma_map_single(&dev->pdev->dev,
                                                          req->buf,
                                                          usbreq->length,
                                                          DMA_FROM_DEVICE);
                }
                req->dma_mapped = 1;
        }
        if (usbreq->length > 0) {
                retval = prepare_dma(ep, req, GFP_ATOMIC);
                if (retval)
                        goto probe_end;
        }
        usbreq->actual = 0;
        usbreq->status = -EINPROGRESS;
        req->dma_done = 0;
        if (list_empty(&ep->queue) && !ep->halted) {
                /* no pending transfer, so start this req */
                if (!usbreq->length) {
                        process_zlp(ep, req);
                        retval = 0;
                        goto probe_end;
                }
                if (!ep->in) {
                        pch_udc_start_rxrequest(ep, req);
                } else {
                        /*
                        * For IN trfr the descriptors will be programmed and
                        * P bit will be set when
                        * we get an IN token
                        */
                        pch_udc_wait_ep_stall(ep);
                        pch_udc_ep_clear_nak(ep);
                        pch_udc_enable_ep_interrupts(ep->dev, (1 << ep->num));
                }
        }
        /* Now add this request to the ep's pending requests */
        if (req != NULL)
                list_add_tail(&req->queue, &ep->queue);

probe_end:
        spin_unlock_irqrestore(&dev->lock, iflags);
        return retval;
}

/**
 * pch_udc_pcd_dequeue() - This function de-queues a request packet.
 *                              It is called by gadget driver
 * @usbep:      Reference to the USB endpoint structure
 * @usbreq:     Reference to the USB request
 *
 * Return codes:
 *      0:                      Success
 *      linux error number:     Failure
 */
static int pch_udc_pcd_dequeue(struct usb_ep *usbep,
                                struct usb_request *usbreq)
{
        struct pch_udc_ep       *ep;
        struct pch_udc_request  *req;
        struct pch_udc_dev      *dev;
        unsigned long           flags;
        int ret = -EINVAL;

        ep = container_of(usbep, struct pch_udc_ep, ep);
        dev = ep->dev;
        if (!usbep || !usbreq || (!ep->desc && ep->num))
                return ret;
        req = container_of(usbreq, struct pch_udc_request, req);
        spin_lock_irqsave(&ep->dev->lock, flags);
        /* make sure it's still queued on this endpoint */
        list_for_each_entry(req, &ep->queue, queue) {
                if (&req->req == usbreq) {
                        pch_udc_ep_set_nak(ep);
                        if (!list_empty(&req->queue))
                                complete_req(ep, req, -ECONNRESET);
                        ret = 0;
                        break;
                }
        }
        spin_unlock_irqrestore(&ep->dev->lock, flags);
        return ret;
}

/**
 * pch_udc_pcd_set_halt() - This function Sets or clear the endpoint halt
 *                          feature
 * @usbep:      Reference to the USB endpoint structure
 * @halt:       Specifies whether to set or clear the feature
 *
 * Return codes:
 *      0:                      Success
 *      linux error number:     Failure
 */
static int pch_udc_pcd_set_halt(struct usb_ep *usbep, int halt)
{
        struct pch_udc_ep       *ep;
        struct pch_udc_dev      *dev;
        unsigned long iflags;
        int ret;

        if (!usbep)
                return -EINVAL;
        ep = container_of(usbep, struct pch_udc_ep, ep);
        dev = ep->dev;
        if (!ep->desc && !ep->num)
                return -EINVAL;
        if (!ep->dev->driver || (ep->dev->gadget.speed == USB_SPEED_UNKNOWN))
                return -ESHUTDOWN;
        spin_lock_irqsave(&udc_stall_spinlock, iflags);
        if (list_empty(&ep->queue)) {
                if (halt) {
                        if (ep->num == PCH_UDC_EP0)
                                ep->dev->stall = 1;
                        pch_udc_ep_set_stall(ep);
                        pch_udc_enable_ep_interrupts(ep->dev,
                                                     PCH_UDC_EPINT(ep->in,
                                                                   ep->num));
                } else {
                        pch_udc_ep_clear_stall(ep);
                }
                ret = 0;
        } else {
                ret = -EAGAIN;
        }
        spin_unlock_irqrestore(&udc_stall_spinlock, iflags);
        return ret;
}

/**
 * pch_udc_pcd_set_wedge() - This function Sets or clear the endpoint
 *                              halt feature
 * @usbep:      Reference to the USB endpoint structure
 * @halt:       Specifies whether to set or clear the feature
 *
 * Return codes:
 *      0:                      Success
 *      linux error number:     Failure
 */
static int pch_udc_pcd_set_wedge(struct usb_ep *usbep)
{
        struct pch_udc_ep       *ep;
        struct pch_udc_dev      *dev;
        unsigned long iflags;
        int ret;

        if (!usbep)
                return -EINVAL;
        ep = container_of(usbep, struct pch_udc_ep, ep);
        dev = ep->dev;
        if (!ep->desc && !ep->num)
                return -EINVAL;
        if (!ep->dev->driver || (ep->dev->gadget.speed == USB_SPEED_UNKNOWN))
                return -ESHUTDOWN;
        spin_lock_irqsave(&udc_stall_spinlock, iflags);
        if (!list_empty(&ep->queue)) {
                ret = -EAGAIN;
        } else {
                if (ep->num == PCH_UDC_EP0)
                        ep->dev->stall = 1;
                pch_udc_ep_set_stall(ep);
                pch_udc_enable_ep_interrupts(ep->dev,
                                             PCH_UDC_EPINT(ep->in, ep->num));
                ep->dev->prot_stall = 1;
                ret = 0;
        }
        spin_unlock_irqrestore(&udc_stall_spinlock, iflags);
        return ret;
}

/**
 * pch_udc_pcd_fifo_flush() - This function Flush the FIFO of specified endpoint
 * @usbep:      Reference to the USB endpoint structure
 */
static void pch_udc_pcd_fifo_flush(struct usb_ep *usbep)
{
        struct pch_udc_ep  *ep;

        if (!usbep)
                return;

        ep = container_of(usbep, struct pch_udc_ep, ep);
        if (ep->desc || !ep->num)
                pch_udc_ep_fifo_flush(ep, ep->in);
}

static const struct usb_ep_ops pch_udc_ep_ops = {
        .enable         = pch_udc_pcd_ep_enable,
        .disable        = pch_udc_pcd_ep_disable,
        .alloc_request  = pch_udc_alloc_request,
        .free_request   = pch_udc_free_request,
        .queue          = pch_udc_pcd_queue,
        .dequeue        = pch_udc_pcd_dequeue,
        .set_halt       = pch_udc_pcd_set_halt,
        .set_wedge      = pch_udc_pcd_set_wedge,
        .fifo_status    = NULL,
        .fifo_flush     = pch_udc_pcd_fifo_flush,
};

/**
 * pch_udc_init_setup_buff() - This function initializes the SETUP buffer
 * @td_stp:     Reference to the SETP buffer structure
 */
static void pch_udc_init_setup_buff(struct pch_udc_stp_dma_desc *td_stp)
{
        static u32      pky_marker;

        if (!td_stp)
                return;
        td_stp->reserved = ++pky_marker;
        memset(&td_stp->request, 0xFF, sizeof td_stp->request);
        td_stp->status = PCH_UDC_BS_HST_RDY;
}

/**
 * pch_udc_start_next_txrequest() - This function starts
 *                                      the next transmission requirement
 * @ep: Reference to the endpoint structure
 */
static void pch_udc_start_next_txrequest(struct pch_udc_ep *ep)
{
        struct pch_udc_request *req;
        struct pch_udc_data_dma_desc *td_data;

        if (pch_udc_read_ep_control(ep) & UDC_EPCTL_P)
                return;

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

        /* next request */
        req = list_entry(ep->queue.next, struct pch_udc_request, queue);
        if (req->dma_going)
                return;
        if (!req->td_data)
                return;
        pch_udc_wait_ep_stall(ep);
        req->dma_going = 1;
        pch_udc_ep_set_ddptr(ep, 0);
        td_data = req->td_data;
        while (1) {
                td_data->status = (td_data->status & ~PCH_UDC_BUFF_STS) |
                                   PCH_UDC_BS_HST_RDY;
                if ((td_data->status & PCH_UDC_DMA_LAST) == PCH_UDC_DMA_LAST)
                        break;
                td_data = phys_to_virt(td_data->next);
        }
        pch_udc_ep_set_ddptr(ep, req->td_data_phys);
        pch_udc_set_dma(ep->dev, DMA_DIR_TX);
        pch_udc_ep_set_pd(ep);
        pch_udc_enable_ep_interrupts(ep->dev, PCH_UDC_EPINT(ep->in, ep->num));
        pch_udc_ep_clear_nak(ep);
}

/**
 * pch_udc_complete_transfer() - This function completes a transfer
 * @ep:         Reference to the endpoint structure
 */
static void pch_udc_complete_transfer(struct pch_udc_ep *ep)
{
        struct pch_udc_request *req;
        struct pch_udc_dev *dev = ep->dev;

        if (list_empty(&ep->queue))
                return;
        req = list_entry(ep->queue.next, struct pch_udc_request, queue);
        if ((req->td_data_last->status & PCH_UDC_BUFF_STS) !=
            PCH_UDC_BS_DMA_DONE)
                return;
        if ((req->td_data_last->status & PCH_UDC_RXTX_STS) !=
             PCH_UDC_RTS_SUCC) {
                dev_err(&dev->pdev->dev, "Invalid RXTX status (0x%08x) "
                        "epstatus=0x%08x\n",
                       (req->td_data_last->status & PCH_UDC_RXTX_STS),
                       (int)(ep->epsts));
                return;
        }

        req->req.actual = req->req.length;
        req->td_data_last->status = PCH_UDC_BS_HST_BSY | PCH_UDC_DMA_LAST;
        req->td_data->status = PCH_UDC_BS_HST_BSY | PCH_UDC_DMA_LAST;
        complete_req(ep, req, 0);
        req->dma_going = 0;
        if (!list_empty(&ep->queue)) {
                pch_udc_wait_ep_stall(ep);
                pch_udc_ep_clear_nak(ep);
                pch_udc_enable_ep_interrupts(ep->dev,
                                             PCH_UDC_EPINT(ep->in, ep->num));
        } else {
                pch_udc_disable_ep_interrupts(ep->dev,
                                              PCH_UDC_EPINT(ep->in, ep->num));
        }
}

/**
 * pch_udc_complete_receiver() - This function completes a receiver
 * @ep:         Reference to the endpoint structure
 */
static void pch_udc_complete_receiver(struct pch_udc_ep *ep)
{
        struct pch_udc_request *req;
        struct pch_udc_dev *dev = ep->dev;
        unsigned int count;
        struct pch_udc_data_dma_desc *td;
        dma_addr_t addr;

        if (list_empty(&ep->queue))
                return;
        /* next request */
        req = list_entry(ep->queue.next, struct pch_udc_request, queue);
        pch_udc_clear_dma(ep->dev, DMA_DIR_RX);
        pch_udc_ep_set_ddptr(ep, 0);
        if ((req->td_data_last->status & PCH_UDC_BUFF_STS) ==
            PCH_UDC_BS_DMA_DONE)
                td = req->td_data_last;
        else
                td = req->td_data;

        while (1) {
                if ((td->status & PCH_UDC_RXTX_STS) != PCH_UDC_RTS_SUCC) {
                        dev_err(&dev->pdev->dev, "Invalid RXTX status=0x%08x "
                                "epstatus=0x%08x\n",
                                (req->td_data->status & PCH_UDC_RXTX_STS),
                                (int)(ep->epsts));
                        return;
                }
                if ((td->status & PCH_UDC_BUFF_STS) == PCH_UDC_BS_DMA_DONE)
                        if (td->status | PCH_UDC_DMA_LAST) {
                                count = td->status & PCH_UDC_RXTX_BYTES;
                                break;
                        }
                if (td == req->td_data_last) {
                        dev_err(&dev->pdev->dev, "Not complete RX descriptor");
                        return;
                }
                addr = (dma_addr_t)td->next;
                td = phys_to_virt(addr);
        }
        /* on 64k packets the RXBYTES field is zero */
        if (!count && (req->req.length == UDC_DMA_MAXPACKET))
                count = UDC_DMA_MAXPACKET;
        req->td_data->status |= PCH_UDC_DMA_LAST;
        td->status |= PCH_UDC_BS_HST_BSY;

        req->dma_going = 0;
        req->req.actual = count;
        complete_req(ep, req, 0);
        /* If there is a new/failed requests try that now */
        if (!list_empty(&ep->queue)) {
                req = list_entry(ep->queue.next, struct pch_udc_request, queue);
                pch_udc_start_rxrequest(ep, req);
        }
}

/**
 * pch_udc_svc_data_in() - This function process endpoint interrupts
 *                              for IN endpoints
 * @dev:        Reference to the device structure
 * @ep_num:     Endpoint that generated the interrupt
 */
static void pch_udc_svc_data_in(struct pch_udc_dev *dev, int ep_num)
{
        u32     epsts;
        struct pch_udc_ep       *ep;