Add linux-next specific files for 20110421

[linux-2.6/next.git] / drivers / usb / gadget / s3c-hsotg.c

/* linux/drivers/usb/gadget/s3c-hsotg.c
 *
 * Copyright 2008 Openmoko, Inc.
 * Copyright 2008 Simtec Electronics
 *      Ben Dooks <ben@simtec.co.uk>
 *      http://armlinux.simtec.co.uk/
 *
 * S3C USB2.0 High-speed / OtG driver
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
*/

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/clk.h>

#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>

#include <mach/map.h>

#include <plat/regs-usb-hsotg-phy.h>
#include <plat/regs-usb-hsotg.h>
#include <mach/regs-sys.h>
#include <plat/udc-hs.h>
#include <plat/cpu.h>

#define DMA_ADDR_INVALID (~((dma_addr_t)0))

/* EP0_MPS_LIMIT
 *
 * Unfortunately there seems to be a limit of the amount of data that can
 * be transferred by IN transactions on EP0. This is either 127 bytes or 3
 * packets (which practically means 1 packet and 63 bytes of data) when the
 * MPS is set to 64.
 *
 * This means if we are wanting to move >127 bytes of data, we need to
 * split the transactions up, but just doing one packet at a time does
 * not work (this may be an implicit DATA0 PID on first packet of the
 * transaction) and doing 2 packets is outside the controller's limits.
 *
 * If we try to lower the MPS size for EP0, then no transfers work properly
 * for EP0, and the system will fail basic enumeration. As no cause for this
 * has currently been found, we cannot support any large IN transfers for
 * EP0.
 */
#define EP0_MPS_LIMIT   64

struct s3c_hsotg;
struct s3c_hsotg_req;

/**
 * struct s3c_hsotg_ep - driver endpoint definition.
 * @ep: The gadget layer representation of the endpoint.
 * @name: The driver generated name for the endpoint.
 * @queue: Queue of requests for this endpoint.
 * @parent: Reference back to the parent device structure.
 * @req: The current request that the endpoint is processing. This is
 *       used to indicate an request has been loaded onto the endpoint
 *       and has yet to be completed (maybe due to data move, or simply
 *       awaiting an ack from the core all the data has been completed).
 * @debugfs: File entry for debugfs file for this endpoint.
 * @lock: State lock to protect contents of endpoint.
 * @dir_in: Set to true if this endpoint is of the IN direction, which
 *          means that it is sending data to the Host.
 * @index: The index for the endpoint registers.
 * @name: The name array passed to the USB core.
 * @halted: Set if the endpoint has been halted.
 * @periodic: Set if this is a periodic ep, such as Interrupt
 * @sent_zlp: Set if we've sent a zero-length packet.
 * @total_data: The total number of data bytes done.
 * @fifo_size: The size of the FIFO (for periodic IN endpoints)
 * @fifo_load: The amount of data loaded into the FIFO (periodic IN)
 * @last_load: The offset of data for the last start of request.
 * @size_loaded: The last loaded size for DxEPTSIZE for periodic IN
 *
 * This is the driver's state for each registered enpoint, allowing it
 * to keep track of transactions that need doing. Each endpoint has a
 * lock to protect the state, to try and avoid using an overall lock
 * for the host controller as much as possible.
 *
 * For periodic IN endpoints, we have fifo_size and fifo_load to try
 * and keep track of the amount of data in the periodic FIFO for each
 * of these as we don't have a status register that tells us how much
 * is in each of them. (note, this may actually be useless information
 * as in shared-fifo mode periodic in acts like a single-frame packet
 * buffer than a fifo)
 */
struct s3c_hsotg_ep {
        struct usb_ep           ep;
        struct list_head        queue;
        struct s3c_hsotg        *parent;
        struct s3c_hsotg_req    *req;
        struct dentry           *debugfs;

        spinlock_t              lock;

        unsigned long           total_data;
        unsigned int            size_loaded;
        unsigned int            last_load;
        unsigned int            fifo_load;
        unsigned short          fifo_size;

        unsigned char           dir_in;
        unsigned char           index;

        unsigned int            halted:1;
        unsigned int            periodic:1;
        unsigned int            sent_zlp:1;

        char                    name[10];
};

#define S3C_HSOTG_EPS   (8+1)   /* limit to 9 for the moment */

/**
 * struct s3c_hsotg - driver state.
 * @dev: The parent device supplied to the probe function
 * @driver: USB gadget driver
 * @plat: The platform specific configuration data.
 * @regs: The memory area mapped for accessing registers.
 * @regs_res: The resource that was allocated when claiming register space.
 * @irq: The IRQ number we are using
 * @dedicated_fifos: Set if the hardware has dedicated IN-EP fifos.
 * @debug_root: root directrory for debugfs.
 * @debug_file: main status file for debugfs.
 * @debug_fifo: FIFO status file for debugfs.
 * @ep0_reply: Request used for ep0 reply.
 * @ep0_buff: Buffer for EP0 reply data, if needed.
 * @ctrl_buff: Buffer for EP0 control requests.
 * @ctrl_req: Request for EP0 control packets.
 * @eps: The endpoints being supplied to the gadget framework
 */
struct s3c_hsotg {
        struct device            *dev;
        struct usb_gadget_driver *driver;
        struct s3c_hsotg_plat    *plat;

        void __iomem            *regs;
        struct resource         *regs_res;
        int                     irq;
        struct clk              *clk;

        unsigned int            dedicated_fifos:1;

        struct dentry           *debug_root;
        struct dentry           *debug_file;
        struct dentry           *debug_fifo;

        struct usb_request      *ep0_reply;
        struct usb_request      *ctrl_req;
        u8                      ep0_buff[8];
        u8                      ctrl_buff[8];

        struct usb_gadget       gadget;
        struct s3c_hsotg_ep     eps[];
};

/**
 * struct s3c_hsotg_req - data transfer request
 * @req: The USB gadget request
 * @queue: The list of requests for the endpoint this is queued for.
 * @in_progress: Has already had size/packets written to core
 * @mapped: DMA buffer for this request has been mapped via dma_map_single().
 */
struct s3c_hsotg_req {
        struct usb_request      req;
        struct list_head        queue;
        unsigned char           in_progress;
        unsigned char           mapped;
};

/* conversion functions */
static inline struct s3c_hsotg_req *our_req(struct usb_request *req)
{
        return container_of(req, struct s3c_hsotg_req, req);
}

static inline struct s3c_hsotg_ep *our_ep(struct usb_ep *ep)
{
        return container_of(ep, struct s3c_hsotg_ep, ep);
}

static inline struct s3c_hsotg *to_hsotg(struct usb_gadget *gadget)
{
        return container_of(gadget, struct s3c_hsotg, gadget);
}

static inline void __orr32(void __iomem *ptr, u32 val)
{
        writel(readl(ptr) | val, ptr);
}

static inline void __bic32(void __iomem *ptr, u32 val)
{
        writel(readl(ptr) & ~val, ptr);
}

/* forward decleration of functions */
static void s3c_hsotg_dump(struct s3c_hsotg *hsotg);

/**
 * using_dma - return the DMA status of the driver.
 * @hsotg: The driver state.
 *
 * Return true if we're using DMA.
 *
 * Currently, we have the DMA support code worked into everywhere
 * that needs it, but the AMBA DMA implementation in the hardware can
 * only DMA from 32bit aligned addresses. This means that gadgets such
 * as the CDC Ethernet cannot work as they often pass packets which are
 * not 32bit aligned.
 *
 * Unfortunately the choice to use DMA or not is global to the controller
 * and seems to be only settable when the controller is being put through
 * a core reset. This means we either need to fix the gadgets to take
 * account of DMA alignment, or add bounce buffers (yuerk).
 *
 * Until this issue is sorted out, we always return 'false'.
 */
static inline bool using_dma(struct s3c_hsotg *hsotg)
{
        return false;   /* support is not complete */
}

/**
 * s3c_hsotg_en_gsint - enable one or more of the general interrupt
 * @hsotg: The device state
 * @ints: A bitmask of the interrupts to enable
 */
static void s3c_hsotg_en_gsint(struct s3c_hsotg *hsotg, u32 ints)
{
        u32 gsintmsk = readl(hsotg->regs + S3C_GINTMSK);
        u32 new_gsintmsk;

        new_gsintmsk = gsintmsk | ints;

        if (new_gsintmsk != gsintmsk) {
                dev_dbg(hsotg->dev, "gsintmsk now 0x%08x\n", new_gsintmsk);
                writel(new_gsintmsk, hsotg->regs + S3C_GINTMSK);
        }
}

/**
 * s3c_hsotg_disable_gsint - disable one or more of the general interrupt
 * @hsotg: The device state
 * @ints: A bitmask of the interrupts to enable
 */
static void s3c_hsotg_disable_gsint(struct s3c_hsotg *hsotg, u32 ints)
{
        u32 gsintmsk = readl(hsotg->regs + S3C_GINTMSK);
        u32 new_gsintmsk;

        new_gsintmsk = gsintmsk & ~ints;

        if (new_gsintmsk != gsintmsk)
                writel(new_gsintmsk, hsotg->regs + S3C_GINTMSK);
}

/**
 * s3c_hsotg_ctrl_epint - enable/disable an endpoint irq
 * @hsotg: The device state
 * @ep: The endpoint index
 * @dir_in: True if direction is in.
 * @en: The enable value, true to enable
 *
 * Set or clear the mask for an individual endpoint's interrupt
 * request.
 */
static void s3c_hsotg_ctrl_epint(struct s3c_hsotg *hsotg,
                                 unsigned int ep, unsigned int dir_in,
                                 unsigned int en)
{
        unsigned long flags;
        u32 bit = 1 << ep;
        u32 daint;

        if (!dir_in)
                bit <<= 16;

        local_irq_save(flags);
        daint = readl(hsotg->regs + S3C_DAINTMSK);
        if (en)
                daint |= bit;
        else
                daint &= ~bit;
        writel(daint, hsotg->regs + S3C_DAINTMSK);
        local_irq_restore(flags);
}

/**
 * s3c_hsotg_init_fifo - initialise non-periodic FIFOs
 * @hsotg: The device instance.
 */
static void s3c_hsotg_init_fifo(struct s3c_hsotg *hsotg)
{
        unsigned int ep;
        unsigned int addr;
        unsigned int size;
        int timeout;
        u32 val;

        /* the ryu 2.6.24 release ahs
           writel(0x1C0, hsotg->regs + S3C_GRXFSIZ);
           writel(S3C_GNPTXFSIZ_NPTxFStAddr(0x200) |
                S3C_GNPTXFSIZ_NPTxFDep(0x1C0),
                hsotg->regs + S3C_GNPTXFSIZ);
        */

        /* set FIFO sizes to 2048/1024 */

        writel(2048, hsotg->regs + S3C_GRXFSIZ);
        writel(S3C_GNPTXFSIZ_NPTxFStAddr(2048) |
               S3C_GNPTXFSIZ_NPTxFDep(1024),
               hsotg->regs + S3C_GNPTXFSIZ);

        /* arange all the rest of the TX FIFOs, as some versions of this
         * block have overlapping default addresses. This also ensures
         * that if the settings have been changed, then they are set to
         * known values. */

        /* start at the end of the GNPTXFSIZ, rounded up */
        addr = 2048 + 1024;
        size = 768;

        /* currently we allocate TX FIFOs for all possible endpoints,
         * and assume that they are all the same size. */

        for (ep = 0; ep <= 15; ep++) {
                val = addr;
                val |= size << S3C_DPTXFSIZn_DPTxFSize_SHIFT;
                addr += size;

                writel(val, hsotg->regs + S3C_DPTXFSIZn(ep));
        }

        /* according to p428 of the design guide, we need to ensure that
         * all fifos are flushed before continuing */

        writel(S3C_GRSTCTL_TxFNum(0x10) | S3C_GRSTCTL_TxFFlsh |
               S3C_GRSTCTL_RxFFlsh, hsotg->regs + S3C_GRSTCTL);

        /* wait until the fifos are both flushed */
        timeout = 100;
        while (1) {
                val = readl(hsotg->regs + S3C_GRSTCTL);

                if ((val & (S3C_GRSTCTL_TxFFlsh | S3C_GRSTCTL_RxFFlsh)) == 0)
                        break;

                if (--timeout == 0) {
                        dev_err(hsotg->dev,
                                "%s: timeout flushing fifos (GRSTCTL=%08x)\n",
                                __func__, val);
                }

                udelay(1);
        }

        dev_dbg(hsotg->dev, "FIFOs reset, timeout at %d\n", timeout);
}

/**
 * @ep: USB endpoint to allocate request for.
 * @flags: Allocation flags
 *
 * Allocate a new USB request structure appropriate for the specified endpoint
 */
static struct usb_request *s3c_hsotg_ep_alloc_request(struct usb_ep *ep,
                                                      gfp_t flags)
{
        struct s3c_hsotg_req *req;

        req = kzalloc(sizeof(struct s3c_hsotg_req), flags);
        if (!req)
                return NULL;

        INIT_LIST_HEAD(&req->queue);

        req->req.dma = DMA_ADDR_INVALID;
        return &req->req;
}

/**
 * is_ep_periodic - return true if the endpoint is in periodic mode.
 * @hs_ep: The endpoint to query.
 *
 * Returns true if the endpoint is in periodic mode, meaning it is being
 * used for an Interrupt or ISO transfer.
 */
static inline int is_ep_periodic(struct s3c_hsotg_ep *hs_ep)
{
        return hs_ep->periodic;
}

/**
 * s3c_hsotg_unmap_dma - unmap the DMA memory being used for the request
 * @hsotg: The device state.
 * @hs_ep: The endpoint for the request
 * @hs_req: The request being processed.
 *
 * This is the reverse of s3c_hsotg_map_dma(), called for the completion
 * of a request to ensure the buffer is ready for access by the caller.
*/
static void s3c_hsotg_unmap_dma(struct s3c_hsotg *hsotg,
                                struct s3c_hsotg_ep *hs_ep,
                                struct s3c_hsotg_req *hs_req)
{
        struct usb_request *req = &hs_req->req;
        enum dma_data_direction dir;

        dir = hs_ep->dir_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE;

        /* ignore this if we're not moving any data */
        if (hs_req->req.length == 0)
                return;

        if (hs_req->mapped) {
                /* we mapped this, so unmap and remove the dma */

                dma_unmap_single(hsotg->dev, req->dma, req->length, dir);

                req->dma = DMA_ADDR_INVALID;
                hs_req->mapped = 0;
        } else {
                dma_sync_single_for_cpu(hsotg->dev, req->dma, req->length, dir);
        }
}

/**
 * s3c_hsotg_write_fifo - write packet Data to the TxFIFO
 * @hsotg: The controller state.
 * @hs_ep: The endpoint we're going to write for.
 * @hs_req: The request to write data for.
 *
 * This is called when the TxFIFO has some space in it to hold a new
 * transmission and we have something to give it. The actual setup of
 * the data size is done elsewhere, so all we have to do is to actually
 * write the data.
 *
 * The return value is zero if there is more space (or nothing was done)
 * otherwise -ENOSPC is returned if the FIFO space was used up.
 *
 * This routine is only needed for PIO
*/
static int s3c_hsotg_write_fifo(struct s3c_hsotg *hsotg,
                                struct s3c_hsotg_ep *hs_ep,
                                struct s3c_hsotg_req *hs_req)
{
        bool periodic = is_ep_periodic(hs_ep);
        u32 gnptxsts = readl(hsotg->regs + S3C_GNPTXSTS);
        int buf_pos = hs_req->req.actual;
        int to_write = hs_ep->size_loaded;
        void *data;
        int can_write;
        int pkt_round;

        to_write -= (buf_pos - hs_ep->last_load);

        /* if there's nothing to write, get out early */
        if (to_write == 0)
                return 0;

        if (periodic && !hsotg->dedicated_fifos) {
                u32 epsize = readl(hsotg->regs + S3C_DIEPTSIZ(hs_ep->index));
                int size_left;
                int size_done;

                /* work out how much data was loaded so we can calculate
                 * how much data is left in the fifo. */

                size_left = S3C_DxEPTSIZ_XferSize_GET(epsize);

                /* if shared fifo, we cannot write anything until the
                 * previous data has been completely sent.
                 */
                if (hs_ep->fifo_load != 0) {
                        s3c_hsotg_en_gsint(hsotg, S3C_GINTSTS_PTxFEmp);
                        return -ENOSPC;
                }

                dev_dbg(hsotg->dev, "%s: left=%d, load=%d, fifo=%d, size %d\n",
                        __func__, size_left,
                        hs_ep->size_loaded, hs_ep->fifo_load, hs_ep->fifo_size);

                /* how much of the data has moved */
                size_done = hs_ep->size_loaded - size_left;

                /* how much data is left in the fifo */
                can_write = hs_ep->fifo_load - size_done;
                dev_dbg(hsotg->dev, "%s: => can_write1=%d\n",
                        __func__, can_write);

                can_write = hs_ep->fifo_size - can_write;
                dev_dbg(hsotg->dev, "%s: => can_write2=%d\n",
                        __func__, can_write);

                if (can_write <= 0) {
                        s3c_hsotg_en_gsint(hsotg, S3C_GINTSTS_PTxFEmp);
                        return -ENOSPC;
                }
        } else if (hsotg->dedicated_fifos && hs_ep->index != 0) {
                can_write = readl(hsotg->regs + S3C_DTXFSTS(hs_ep->index));

                can_write &= 0xffff;
                can_write *= 4;
        } else {
                if (S3C_GNPTXSTS_NPTxQSpcAvail_GET(gnptxsts) == 0) {
                        dev_dbg(hsotg->dev,
                                "%s: no queue slots available (0x%08x)\n",
                                __func__, gnptxsts);

                        s3c_hsotg_en_gsint(hsotg, S3C_GINTSTS_NPTxFEmp);
                        return -ENOSPC;
                }

                can_write = S3C_GNPTXSTS_NPTxFSpcAvail_GET(gnptxsts);
                can_write *= 4; /* fifo size is in 32bit quantities. */
        }

        dev_dbg(hsotg->dev, "%s: GNPTXSTS=%08x, can=%d, to=%d, mps %d\n",
                 __func__, gnptxsts, can_write, to_write, hs_ep->ep.maxpacket);

        /* limit to 512 bytes of data, it seems at least on the non-periodic
         * FIFO, requests of >512 cause the endpoint to get stuck with a
         * fragment of the end of the transfer in it.
         */
        if (can_write > 512)
                can_write = 512;

        /* limit the write to one max-packet size worth of data, but allow
         * the transfer to return that it did not run out of fifo space
         * doing it. */
        if (to_write > hs_ep->ep.maxpacket) {
                to_write = hs_ep->ep.maxpacket;

                s3c_hsotg_en_gsint(hsotg,
                                   periodic ? S3C_GINTSTS_PTxFEmp :
                                   S3C_GINTSTS_NPTxFEmp);
        }

        /* see if we can write data */

        if (to_write > can_write) {
                to_write = can_write;
                pkt_round = to_write % hs_ep->ep.maxpacket;

                /* Not sure, but we probably shouldn't be writing partial
                 * packets into the FIFO, so round the write down to an
                 * exact number of packets.
                 *
                 * Note, we do not currently check to see if we can ever
                 * write a full packet or not to the FIFO.
                 */

                if (pkt_round)
                        to_write -= pkt_round;

                /* enable correct FIFO interrupt to alert us when there
                 * is more room left. */

                s3c_hsotg_en_gsint(hsotg,
                                   periodic ? S3C_GINTSTS_PTxFEmp :
                                   S3C_GINTSTS_NPTxFEmp);
        }

        dev_dbg(hsotg->dev, "write %d/%d, can_write %d, done %d\n",
                 to_write, hs_req->req.length, can_write, buf_pos);

        if (to_write <= 0)
                return -ENOSPC;

        hs_req->req.actual = buf_pos + to_write;
        hs_ep->total_data += to_write;

        if (periodic)
                hs_ep->fifo_load += to_write;

        to_write = DIV_ROUND_UP(to_write, 4);
        data = hs_req->req.buf + buf_pos;

        writesl(hsotg->regs + S3C_EPFIFO(hs_ep->index), data, to_write);

        return (to_write >= can_write) ? -ENOSPC : 0;
}

/**
 * get_ep_limit - get the maximum data legnth for this endpoint
 * @hs_ep: The endpoint
 *
 * Return the maximum data that can be queued in one go on a given endpoint
 * so that transfers that are too long can be split.
 */
static unsigned get_ep_limit(struct s3c_hsotg_ep *hs_ep)
{
        int index = hs_ep->index;
        unsigned maxsize;
        unsigned maxpkt;

        if (index != 0) {
                maxsize = S3C_DxEPTSIZ_XferSize_LIMIT + 1;
                maxpkt = S3C_DxEPTSIZ_PktCnt_LIMIT + 1;
        } else {
                maxsize = 64+64;
                if (hs_ep->dir_in) {
                        maxpkt = S3C_DIEPTSIZ0_PktCnt_LIMIT + 1;
                } else {
                        maxpkt = 2;
                }
        }

        /* we made the constant loading easier above by using +1 */
        maxpkt--;
        maxsize--;

        /* constrain by packet count if maxpkts*pktsize is greater
         * than the length register size. */

        if ((maxpkt * hs_ep->ep.maxpacket) < maxsize)
                maxsize = maxpkt * hs_ep->ep.maxpacket;

        return maxsize;
}

/**
 * s3c_hsotg_start_req - start a USB request from an endpoint's queue
 * @hsotg: The controller state.
 * @hs_ep: The endpoint to process a request for
 * @hs_req: The request to start.
 * @continuing: True if we are doing more for the current request.
 *
 * Start the given request running by setting the endpoint registers
 * appropriately, and writing any data to the FIFOs.
 */
static void s3c_hsotg_start_req(struct s3c_hsotg *hsotg,
                                struct s3c_hsotg_ep *hs_ep,
                                struct s3c_hsotg_req *hs_req,
                                bool continuing)
{
        struct usb_request *ureq = &hs_req->req;
        int index = hs_ep->index;
        int dir_in = hs_ep->dir_in;
        u32 epctrl_reg;
        u32 epsize_reg;
        u32 epsize;
        u32 ctrl;
        unsigned length;
        unsigned packets;
        unsigned maxreq;

        if (index != 0) {
                if (hs_ep->req && !continuing) {
                        dev_err(hsotg->dev, "%s: active request\n", __func__);
                        WARN_ON(1);
                        return;
                } else if (hs_ep->req != hs_req && continuing) {
                        dev_err(hsotg->dev,
                                "%s: continue different req\n", __func__);
                        WARN_ON(1);
                        return;
                }
        }

        epctrl_reg = dir_in ? S3C_DIEPCTL(index) : S3C_DOEPCTL(index);
        epsize_reg = dir_in ? S3C_DIEPTSIZ(index) : S3C_DOEPTSIZ(index);

        dev_dbg(hsotg->dev, "%s: DxEPCTL=0x%08x, ep %d, dir %s\n",
                __func__, readl(hsotg->regs + epctrl_reg), index,
                hs_ep->dir_in ? "in" : "out");

        length = ureq->length - ureq->actual;

        if (0)
                dev_dbg(hsotg->dev,
                        "REQ buf %p len %d dma 0x%08x noi=%d zp=%d snok=%d\n",
                        ureq->buf, length, ureq->dma,
                        ureq->no_interrupt, ureq->zero, ureq->short_not_ok);

        maxreq = get_ep_limit(hs_ep);
        if (length > maxreq) {
                int round = maxreq % hs_ep->ep.maxpacket;

                dev_dbg(hsotg->dev, "%s: length %d, max-req %d, r %d\n",
                        __func__, length, maxreq, round);

                /* round down to multiple of packets */
                if (round)
                        maxreq -= round;

                length = maxreq;
        }

        if (length)
                packets = DIV_ROUND_UP(length, hs_ep->ep.maxpacket);
        else
                packets = 1;    /* send one packet if length is zero. */

        if (dir_in && index != 0)
                epsize = S3C_DxEPTSIZ_MC(1);
        else
                epsize = 0;

        if (index != 0 && ureq->zero) {
                /* test for the packets being exactly right for the
                 * transfer */

                if (length == (packets * hs_ep->ep.maxpacket))
                        packets++;
        }

        epsize |= S3C_DxEPTSIZ_PktCnt(packets);
        epsize |= S3C_DxEPTSIZ_XferSize(length);

        dev_dbg(hsotg->dev, "%s: %d@%d/%d, 0x%08x => 0x%08x\n",
                __func__, packets, length, ureq->length, epsize, epsize_reg);

        /* store the request as the current one we're doing */
        hs_ep->req = hs_req;

        /* write size / packets */
        writel(epsize, hsotg->regs + epsize_reg);

        ctrl = readl(hsotg->regs + epctrl_reg);

        if (ctrl & S3C_DxEPCTL_Stall) {
                dev_warn(hsotg->dev, "%s: ep%d is stalled\n", __func__, index);

                /* not sure what we can do here, if it is EP0 then we should
                 * get this cleared once the endpoint has transmitted the
                 * STALL packet, otherwise it needs to be cleared by the
                 * host.
                 */
        }

        if (using_dma(hsotg)) {
                unsigned int dma_reg;

                /* write DMA address to control register, buffer already
                 * synced by s3c_hsotg_ep_queue().  */

                dma_reg = dir_in ? S3C_DIEPDMA(index) : S3C_DOEPDMA(index);
                writel(ureq->dma, hsotg->regs + dma_reg);

                dev_dbg(hsotg->dev, "%s: 0x%08x => 0x%08x\n",
                        __func__, ureq->dma, dma_reg);
        }

        ctrl |= S3C_DxEPCTL_EPEna;      /* ensure ep enabled */
        ctrl |= S3C_DxEPCTL_USBActEp;
        ctrl |= S3C_DxEPCTL_CNAK;       /* clear NAK set by core */

        dev_dbg(hsotg->dev, "%s: DxEPCTL=0x%08x\n", __func__, ctrl);
        writel(ctrl, hsotg->regs + epctrl_reg);

        /* set these, it seems that DMA support increments past the end
         * of the packet buffer so we need to calculate the length from
         * this information. */
        hs_ep->size_loaded = length;
        hs_ep->last_load = ureq->actual;

        if (dir_in && !using_dma(hsotg)) {
                /* set these anyway, we may need them for non-periodic in */
                hs_ep->fifo_load = 0;

                s3c_hsotg_write_fifo(hsotg, hs_ep, hs_req);
        }

        /* clear the INTknTXFEmpMsk when we start request, more as a aide
         * to debugging to see what is going on. */
        if (dir_in)
                writel(S3C_DIEPMSK_INTknTXFEmpMsk,
                       hsotg->regs + S3C_DIEPINT(index));

        /* Note, trying to clear the NAK here causes problems with transmit
         * on the S3C6400 ending up with the TXFIFO becoming full. */

        /* check ep is enabled */
        if (!(readl(hsotg->regs + epctrl_reg) & S3C_DxEPCTL_EPEna))
                dev_warn(hsotg->dev,
                         "ep%d: failed to become enabled (DxEPCTL=0x%08x)?\n",
                         index, readl(hsotg->regs + epctrl_reg));

        dev_dbg(hsotg->dev, "%s: DxEPCTL=0x%08x\n",
                __func__, readl(hsotg->regs + epctrl_reg));
}

/**
 * s3c_hsotg_map_dma - map the DMA memory being used for the request
 * @hsotg: The device state.
 * @hs_ep: The endpoint the request is on.
 * @req: The request being processed.
 *
 * We've been asked to queue a request, so ensure that the memory buffer
 * is correctly setup for DMA. If we've been passed an extant DMA address
 * then ensure the buffer has been synced to memory. If our buffer has no
 * DMA memory, then we map the memory and mark our request to allow us to
 * cleanup on completion.
*/
static int s3c_hsotg_map_dma(struct s3c_hsotg *hsotg,
                             struct s3c_hsotg_ep *hs_ep,
                             struct usb_request *req)
{
        enum dma_data_direction dir;
        struct s3c_hsotg_req *hs_req = our_req(req);

        dir = hs_ep->dir_in ? DMA_TO_DEVICE : DMA_FROM_DEVICE;

        /* if the length is zero, ignore the DMA data */
        if (hs_req->req.length == 0)
                return 0;

        if (req->dma == DMA_ADDR_INVALID) {
                dma_addr_t dma;

                dma = dma_map_single(hsotg->dev, req->buf, req->length, dir);

                if (unlikely(dma_mapping_error(hsotg->dev, dma)))
                        goto dma_error;

                if (dma & 3) {
                        dev_err(hsotg->dev, "%s: unaligned dma buffer\n",
                                __func__);

                        dma_unmap_single(hsotg->dev, dma, req->length, dir);
                        return -EINVAL;
                }

                hs_req->mapped = 1;
                req->dma = dma;
        } else {
                dma_sync_single_for_cpu(hsotg->dev, req->dma, req->length, dir);
                hs_req->mapped = 0;
        }

        return 0;

dma_error:
        dev_err(hsotg->dev, "%s: failed to map buffer %p, %d bytes\n",
                __func__, req->buf, req->length);

        return -EIO;
}

static int s3c_hsotg_ep_queue(struct usb_ep *ep, struct usb_request *req,
                              gfp_t gfp_flags)
{
        struct s3c_hsotg_req *hs_req = our_req(req);
        struct s3c_hsotg_ep *hs_ep = our_ep(ep);
        struct s3c_hsotg *hs = hs_ep->parent;
        unsigned long irqflags;
        bool first;

        dev_dbg(hs->dev, "%s: req %p: %d@%p, noi=%d, zero=%d, snok=%d\n",
                ep->name, req, req->length, req->buf, req->no_interrupt,
                req->zero, req->short_not_ok);

        /* initialise status of the request */
        INIT_LIST_HEAD(&hs_req->queue);
        req->actual = 0;
        req->status = -EINPROGRESS;

        /* if we're using DMA, sync the buffers as necessary */
        if (using_dma(hs)) {
                int ret = s3c_hsotg_map_dma(hs, hs_ep, req);
                if (ret)
                        return ret;
        }

        spin_lock_irqsave(&hs_ep->lock, irqflags);

        first = list_empty(&hs_ep->queue);
        list_add_tail(&hs_req->queue, &hs_ep->queue);

        if (first)
                s3c_hsotg_start_req(hs, hs_ep, hs_req, false);

        spin_unlock_irqrestore(&hs_ep->lock, irqflags);

        return 0;
}

static void s3c_hsotg_ep_free_request(struct usb_ep *ep,
                                      struct usb_request *req)
{
        struct s3c_hsotg_req *hs_req = our_req(req);

        kfree(hs_req);
}

/**
 * s3c_hsotg_complete_oursetup - setup completion callback
 * @ep: The endpoint the request was on.
 * @req: The request completed.
 *
 * Called on completion of any requests the driver itself
 * submitted that need cleaning up.
 */
static void s3c_hsotg_complete_oursetup(struct usb_ep *ep,
                                        struct usb_request *req)
{
        struct s3c_hsotg_ep *hs_ep = our_ep(ep);
        struct s3c_hsotg *hsotg = hs_ep->parent;

        dev_dbg(hsotg->dev, "%s: ep %p, req %p\n", __func__, ep, req);

        s3c_hsotg_ep_free_request(ep, req);
}

/**
 * ep_from_windex - convert control wIndex value to endpoint
 * @hsotg: The driver state.
 * @windex: The control request wIndex field (in host order).
 *
 * Convert the given wIndex into a pointer to an driver endpoint
 * structure, or return NULL if it is not a valid endpoint.
*/
static struct s3c_hsotg_ep *ep_from_windex(struct s3c_hsotg *hsotg,
                                           u32 windex)
{
        struct s3c_hsotg_ep *ep = &hsotg->eps[windex & 0x7F];
        int dir = (windex & USB_DIR_IN) ? 1 : 0;
        int idx = windex & 0x7F;

        if (windex >= 0x100)
                return NULL;

        if (idx > S3C_HSOTG_EPS)
                return NULL;

        if (idx && ep->dir_in != dir)
                return NULL;

        return ep;
}

/**
 * s3c_hsotg_send_reply - send reply to control request
 * @hsotg: The device state
 * @ep: Endpoint 0
 * @buff: Buffer for request
 * @length: Length of reply.
 *
 * Create a request and queue it on the given endpoint. This is useful as
 * an internal method of sending replies to certain control requests, etc.
 */
static int s3c_hsotg_send_reply(struct s3c_hsotg *hsotg,
                                struct s3c_hsotg_ep *ep,
                                void *buff,
                                int length)
{
        struct usb_request *req;
        int ret;

        dev_dbg(hsotg->dev, "%s: buff %p, len %d\n", __func__, buff, length);

        req = s3c_hsotg_ep_alloc_request(&ep->ep, GFP_ATOMIC);
        hsotg->ep0_reply = req;
        if (!req) {
                dev_warn(hsotg->dev, "%s: cannot alloc req\n", __func__);
                return -ENOMEM;
        }

        req->buf = hsotg->ep0_buff;
        req->length = length;
        req->zero = 1; /* always do zero-length final transfer */
        req->complete = s3c_hsotg_complete_oursetup;

        if (length)
                memcpy(req->buf, buff, length);
        else
                ep->sent_zlp = 1;

        ret = s3c_hsotg_ep_queue(&ep->ep, req, GFP_ATOMIC);
        if (ret) {
                dev_warn(hsotg->dev, "%s: cannot queue req\n", __func__);
                return ret;
        }

        return 0;
}

/**
 * s3c_hsotg_process_req_status - process request GET_STATUS
 * @hsotg: The device state
 * @ctrl: USB control request
 */
static int s3c_hsotg_process_req_status(struct s3c_hsotg *hsotg,
                                        struct usb_ctrlrequest *ctrl)
{
        struct s3c_hsotg_ep *ep0 = &hsotg->eps[0];
        struct s3c_hsotg_ep *ep;
        __le16 reply;
        int ret;

        dev_dbg(hsotg->dev, "%s: USB_REQ_GET_STATUS\n", __func__);

        if (!ep0->dir_in) {
                dev_warn(hsotg->dev, "%s: direction out?\n", __func__);
                return -EINVAL;
        }

        switch (ctrl->bRequestType & USB_RECIP_MASK) {
        case USB_RECIP_DEVICE:
                reply = cpu_to_le16(0); /* bit 0 => self powered,
                                         * bit 1 => remote wakeup */
                break;

        case USB_RECIP_INTERFACE:
                /* currently, the data result should be zero */
                reply = cpu_to_le16(0);
                break;

        case USB_RECIP_ENDPOINT:
                ep = ep_from_windex(hsotg, le16_to_cpu(ctrl->wIndex));
                if (!ep)
                        return -ENOENT;

                reply = cpu_to_le16(ep->halted ? 1 : 0);
                break;

        default:
                return 0;
        }

        if (le16_to_cpu(ctrl->wLength) != 2)
                return -EINVAL;

        ret = s3c_hsotg_send_reply(hsotg, ep0, &reply, 2);
        if (ret) {
                dev_err(hsotg->dev, "%s: failed to send reply\n", __func__);
                return ret;
        }

        return 1;
}

static int s3c_hsotg_ep_sethalt(struct usb_ep *ep, int value);

/**
 * s3c_hsotg_process_req_featire - process request {SET,CLEAR}_FEATURE
 * @hsotg: The device state
 * @ctrl: USB control request
 */
static int s3c_hsotg_process_req_feature(struct s3c_hsotg *hsotg,
                                         struct usb_ctrlrequest *ctrl)
{
        bool set = (ctrl->bRequest == USB_REQ_SET_FEATURE);
        struct s3c_hsotg_ep *ep;

        dev_dbg(hsotg->dev, "%s: %s_FEATURE\n",
                __func__, set ? "SET" : "CLEAR");

        if (ctrl->bRequestType == USB_RECIP_ENDPOINT) {
                ep = ep_from_windex(hsotg, le16_to_cpu(ctrl->wIndex));
                if (!ep) {
                        dev_dbg(hsotg->dev, "%s: no endpoint for 0x%04x\n",
                                __func__, le16_to_cpu(ctrl->wIndex));
                        return -ENOENT;
                }

                switch (le16_to_cpu(ctrl->wValue)) {
                case USB_ENDPOINT_HALT:
                        s3c_hsotg_ep_sethalt(&ep->ep, set);
                        break;

                default:
                        return -ENOENT;
                }
        } else
                return -ENOENT;  /* currently only deal with endpoint */

        return 1;
}

/**
 * s3c_hsotg_process_control - process a control request
 * @hsotg: The device state
 * @ctrl: The control request received
 *
 * The controller has received the SETUP phase of a control request, and
 * needs to work out what to do next (and whether to pass it on to the
 * gadget driver).
 */
static void s3c_hsotg_process_control(struct s3c_hsotg *hsotg,
                                      struct usb_ctrlrequest *ctrl)
{
        struct s3c_hsotg_ep *ep0 = &hsotg->eps[0];
        int ret = 0;
        u32 dcfg;

        ep0->sent_zlp = 0;

        dev_dbg(hsotg->dev, "ctrl Req=%02x, Type=%02x, V=%04x, L=%04x\n",
                 ctrl->bRequest, ctrl->bRequestType,
                 ctrl->wValue, ctrl->wLength);

        /* record the direction of the request, for later use when enquing
         * packets onto EP0. */

        ep0->dir_in = (ctrl->bRequestType & USB_DIR_IN) ? 1 : 0;
        dev_dbg(hsotg->dev, "ctrl: dir_in=%d\n", ep0->dir_in);

        /* if we've no data with this request, then the last part of the
         * transaction is going to implicitly be IN. */
        if (ctrl->wLength == 0)
                ep0->dir_in = 1;

        if ((ctrl->bRequestType & USB_TYPE_MASK) == USB_TYPE_STANDARD) {
                switch (ctrl->bRequest) {
                case USB_REQ_SET_ADDRESS:
                        dcfg = readl(hsotg->regs + S3C_DCFG);
                        dcfg &= ~S3C_DCFG_DevAddr_MASK;
                        dcfg |= ctrl->wValue << S3C_DCFG_DevAddr_SHIFT;
                        writel(dcfg, hsotg->regs + S3C_DCFG);

                        dev_info(hsotg->dev, "new address %d\n", ctrl->wValue);

                        ret = s3c_hsotg_send_reply(hsotg, ep0, NULL, 0);
                        return;

                case USB_REQ_GET_STATUS:
                        ret = s3c_hsotg_process_req_status(hsotg, ctrl);
                        break;

                case USB_REQ_CLEAR_FEATURE:
                case USB_REQ_SET_FEATURE:
                        ret = s3c_hsotg_process_req_feature(hsotg, ctrl);
                        break;
                }
        }

        /* as a fallback, try delivering it to the driver to deal with */

        if (ret == 0 && hsotg->driver) {
                ret = hsotg->driver->setup(&hsotg->gadget, ctrl);
                if (ret < 0)
                        dev_dbg(hsotg->dev, "driver->setup() ret %d\n", ret);
        }

        if (ret > 0) {
                if (!ep0->dir_in) {
                        /* need to generate zlp in reply or take data */
                        /* todo - deal with any data we might be sent? */
                        ret = s3c_hsotg_send_reply(hsotg, ep0, NULL, 0);
                }
        }

        /* the request is either unhandlable, or is not formatted correctly
         * so respond with a STALL for the status stage to indicate failure.
         */

        if (ret < 0) {
                u32 reg;
                u32 ctrl;

                dev_dbg(hsotg->dev, "ep0 stall (dir=%d)\n", ep0->dir_in);
                reg = (ep0->dir_in) ? S3C_DIEPCTL0 : S3C_DOEPCTL0;

                /* S3C_DxEPCTL_Stall will be cleared by EP once it has
                 * taken effect, so no need to clear later. */

                ctrl = readl(hsotg->regs + reg);
                ctrl |= S3C_DxEPCTL_Stall;
                ctrl |= S3C_DxEPCTL_CNAK;
                writel(ctrl, hsotg->regs + reg);

                dev_dbg(hsotg->dev,
                        "written DxEPCTL=0x%08x to %08x (DxEPCTL=0x%08x)\n",
                        ctrl, reg, readl(hsotg->regs + reg));

                /* don't believe we need to anything more to get the EP
                 * to reply with a STALL packet */
        }
}

static void s3c_hsotg_enqueue_setup(struct s3c_hsotg *hsotg);

/**
 * s3c_hsotg_complete_setup - completion of a setup transfer
 * @ep: The endpoint the request was on.
 * @req: The request completed.
 *
 * Called on completion of any requests the driver itself submitted for
 * EP0 setup packets
 */
static void s3c_hsotg_complete_setup(struct usb_ep *ep,
                                     struct usb_request *req)
{
        struct s3c_hsotg_ep *hs_ep = our_ep(ep);
        struct s3c_hsotg *hsotg = hs_ep->parent;

        if (req->status < 0) {
                dev_dbg(hsotg->dev, "%s: failed %d\n", __func__, req->status);
                return;
        }

        if (req->actual == 0)
                s3c_hsotg_enqueue_setup(hsotg);
        else
                s3c_hsotg_process_control(hsotg, req->buf);
}

/**
 * s3c_hsotg_enqueue_setup - start a request for EP0 packets
 * @hsotg: The device state.
 *
 * Enqueue a request on EP0 if necessary to received any SETUP packets
 * received from the host.
 */
static void s3c_hsotg_enqueue_setup(struct s3c_hsotg *hsotg)
{
        struct usb_request *req = hsotg->ctrl_req;
        struct s3c_hsotg_req *hs_req = our_req(req);
        int ret;

        dev_dbg(hsotg->dev, "%s: queueing setup request\n", __func__);

        req->zero = 0;
        req->length = 8;
        req->buf = hsotg->ctrl_buff;
        req->complete = s3c_hsotg_complete_setup;

        if (!list_empty(&hs_req->queue)) {
                dev_dbg(hsotg->dev, "%s already queued???\n", __func__);
                return;
        }

        hsotg->eps[0].dir_in = 0;

        ret = s3c_hsotg_ep_queue(&hsotg->eps[0].ep, req, GFP_ATOMIC);
        if (ret < 0) {
                dev_err(hsotg->dev, "%s: failed queue (%d)\n", __func__, ret);
                /* Don't think there's much we can do other than watch the
                 * driver fail. */
        }
}

/**
 * get_ep_head - return the first request on the endpoint
 * @hs_ep: The controller endpoint to get
 *
 * Get the first request on the endpoint.
*/
static struct s3c_hsotg_req *get_ep_head(struct s3c_hsotg_ep *hs_ep)
{
        if (list_empty(&hs_ep->queue))
                return NULL;

        return list_first_entry(&hs_ep->queue, struct s3c_hsotg_req, queue);
}

/**
 * s3c_hsotg_complete_request - complete a request given to us
 * @hsotg: The device state.
 * @hs_ep: The endpoint the request was on.
 * @hs_req: The request to complete.
 * @result: The result code (0 => Ok, otherwise errno)
 *
 * The given request has finished, so call the necessary completion
 * if it has one and then look to see if we can start a new request
 * on the endpoint.
 *
 * Note, expects the ep to already be locked as appropriate.
*/
static void s3c_hsotg_complete_request(struct s3c_hsotg *hsotg,
                                       struct s3c_hsotg_ep *hs_ep,
                                       struct s3c_hsotg_req *hs_req,
                                       int result)
{
        bool restart;

        if (!hs_req) {
                dev_dbg(hsotg->dev, "%s: nothing to complete?\n", __func__);
                return;
        }

        dev_dbg(hsotg->dev, "complete: ep %p %s, req %p, %d => %p\n",
                hs_ep, hs_ep->ep.name, hs_req, result, hs_req->req.complete);

        /* only replace the status if we've not already set an error
         * from a previous transaction */

        if (hs_req->req.status == -EINPROGRESS)
                hs_req->req.status = result;

        hs_ep->req = NULL;
        list_del_init(&hs_req->queue);

        if (using_dma(hsotg))
                s3c_hsotg_unmap_dma(hsotg, hs_ep, hs_req);

        /* call the complete request with the locks off, just in case the
         * request tries to queue more work for this endpoint. */

        if (hs_req->req.complete) {
                spin_unlock(&hs_ep->lock);
                hs_req->req.complete(&hs_ep->ep, &hs_req->req);
                spin_lock(&hs_ep->lock);
        }

        /* Look to see if there is anything else to do. Note, the completion
         * of the previous request may have caused a new request to be started
         * so be careful when doing this. */

        if (!hs_ep->req && result >= 0) {
                restart = !list_empty(&hs_ep->queue);
                if (restart) {
                        hs_req = get_ep_head(hs_ep);
                        s3c_hsotg_start_req(hsotg, hs_ep, hs_req, false);
                }
        }
}

/**
 * s3c_hsotg_complete_request_lock - complete a request given to us (locked)
 * @hsotg: The device state.
 * @hs_ep: The endpoint the request was on.
 * @hs_req: The request to complete.
 * @result: The result code (0 => Ok, otherwise errno)
 *
 * See s3c_hsotg_complete_request(), but called with the endpoint's
 * lock held.
*/
static void s3c_hsotg_complete_request_lock(struct s3c_hsotg *hsotg,
                                            struct s3c_hsotg_ep *hs_ep,
                                            struct s3c_hsotg_req *hs_req,
                                            int result)
{
        unsigned long flags;

        spin_lock_irqsave(&hs_ep->lock, flags);
        s3c_hsotg_complete_request(hsotg, hs_ep, hs_req, result);
        spin_unlock_irqrestore(&hs_ep->lock, flags);
}

/**
 * s3c_hsotg_rx_data - receive data from the FIFO for an endpoint
 * @hsotg: The device state.
 * @ep_idx: The endpoint index for the data
 * @size: The size of data in the fifo, in bytes
 *
 * The FIFO status shows there is data to read from the FIFO for a given
 * endpoint, so sort out whether we need to read the data into a request
 * that has been made for that endpoint.
 */
static void s3c_hsotg_rx_data(struct s3c_hsotg *hsotg, int ep_idx, int size)
{
        struct s3c_hsotg_ep *hs_ep = &hsotg->eps[ep_idx];
        struct s3c_hsotg_req *hs_req = hs_ep->req;
        void __iomem *fifo = hsotg->regs + S3C_EPFIFO(ep_idx);
        int to_read;
        int max_req;
        int read_ptr;

        if (!hs_req) {
                u32 epctl = readl(hsotg->regs + S3C_DOEPCTL(ep_idx));
                int ptr;

                dev_warn(hsotg->dev,
                         "%s: FIFO %d bytes on ep%d but no req (DxEPCTl=0x%08x)\n",
                         __func__, size, ep_idx, epctl);

                /* dump the data from the FIFO, we've nothing we can do */
                for (ptr = 0; ptr < size; ptr += 4)
                        (void)readl(fifo);

                return;
        }

        spin_lock(&hs_ep->lock);

        to_read = size;
        read_ptr = hs_req->req.actual;
        max_req = hs_req->req.length - read_ptr;

        dev_dbg(hsotg->dev, "%s: read %d/%d, done %d/%d\n",
                __func__, to_read, max_req, read_ptr, hs_req->req.length);

        if (to_read > max_req) {
                /* more data appeared than we where willing
                 * to deal with in this request.
                 */

                /* currently we don't deal this */
                WARN_ON_ONCE(1);
        }

        hs_ep->total_data += to_read;
        hs_req->req.actual += to_read;
        to_read = DIV_ROUND_UP(to_read, 4);

        /* note, we might over-write the buffer end by 3 bytes depending on
         * alignment of the data. */
        readsl(fifo, hs_req->req.buf + read_ptr, to_read);

        spin_unlock(&hs_ep->lock);
}

/**
 * s3c_hsotg_send_zlp - send zero-length packet on control endpoint
 * @hsotg: The device instance
 * @req: The request currently on this endpoint
 *
 * Generate a zero-length IN packet request for terminating a SETUP
 * transaction.
 *
 * Note, since we don't write any data to the TxFIFO, then it is
 * currently believed that we do not need to wait for any space in
 * the TxFIFO.
 */
static void s3c_hsotg_send_zlp(struct s3c_hsotg *hsotg,
                               struct s3c_hsotg_req *req)
{
        u32 ctrl;

        if (!req) {
                dev_warn(hsotg->dev, "%s: no request?\n", __func__);
                return;
        }

        if (req->req.length == 0) {
                hsotg->eps[0].sent_zlp = 1;
                s3c_hsotg_enqueue_setup(hsotg);
                return;
        }

        hsotg->eps[0].dir_in = 1;
        hsotg->eps[0].sent_zlp = 1;

        dev_dbg(hsotg->dev, "sending zero-length packet\n");

        /* issue a zero-sized packet to terminate this */
        writel(S3C_DxEPTSIZ_MC(1) | S3C_DxEPTSIZ_PktCnt(1) |
               S3C_DxEPTSIZ_XferSize(0), hsotg->regs + S3C_DIEPTSIZ(0));

        ctrl = readl(hsotg->regs + S3C_DIEPCTL0);
        ctrl |= S3C_DxEPCTL_CNAK;  /* clear NAK set by core */
        ctrl |= S3C_DxEPCTL_EPEna; /* ensure ep enabled */
        ctrl |= S3C_DxEPCTL_USBActEp;
        writel(ctrl, hsotg->regs + S3C_DIEPCTL0);
}

/**
 * s3c_hsotg_handle_outdone - handle receiving OutDone/SetupDone from RXFIFO
 * @hsotg: The device instance
 * @epnum: The endpoint received from
 * @was_setup: Set if processing a SetupDone event.
 *
 * The RXFIFO has delivered an OutDone event, which means that the data
 * transfer for an OUT endpoint has been completed, either by a short
 * packet or by the finish of a transfer.
*/
static void s3c_hsotg_handle_outdone(struct s3c_hsotg *hsotg,
                                     int epnum, bool was_setup)
{
        u32 epsize = readl(hsotg->regs + S3C_DOEPTSIZ(epnum));
        struct s3c_hsotg_ep *hs_ep = &hsotg->eps[epnum];
        struct s3c_hsotg_req *hs_req = hs_ep->req;
        struct usb_request *req = &hs_req->req;
        unsigned size_left = S3C_DxEPTSIZ_XferSize_GET(epsize);
        int result = 0;

        if (!hs_req) {
                dev_dbg(hsotg->dev, "%s: no request active\n", __func__);
                return;
        }

        if (using_dma(hsotg)) {
                unsigned size_done;

                /* Calculate the size of the transfer by checking how much
                 * is left in the endpoint size register and then working it
                 * out from the amount we loaded for the transfer.
                 *
                 * We need to do this as DMA pointers are always 32bit aligned
                 * so may overshoot/undershoot the transfer.
                 */

                size_done = hs_ep->size_loaded - size_left;
                size_done += hs_ep->last_load;

                req->actual = size_done;
        }

        /* if there is more request to do, schedule new transfer */
        if (req->actual < req->length && size_left == 0) {
                s3c_hsotg_start_req(hsotg, hs_ep, hs_req, true);
                return;
        }

        if (req->actual < req->length && req->short_not_ok) {
                dev_dbg(hsotg->dev, "%s: got %d/%d (short not ok) => error\n",
                        __func__, req->actual, req->length);

                /* todo - what should we return here? there's no one else
                 * even bothering to check the status. */
        }

        if (epnum == 0) {
                if (!was_setup && req->complete != s3c_hsotg_complete_setup)
                        s3c_hsotg_send_zlp(hsotg, hs_req);
        }

        s3c_hsotg_complete_request_lock(hsotg, hs_ep, hs_req, result);
}

/**
 * s3c_hsotg_read_frameno - read current frame number
 * @hsotg: The device instance
 *
 * Return the current frame number
*/
static u32 s3c_hsotg_read_frameno(struct s3c_hsotg *hsotg)
{
        u32 dsts;

        dsts = readl(hsotg->regs + S3C_DSTS);
        dsts &= S3C_DSTS_SOFFN_MASK;
        dsts >>= S3C_DSTS_SOFFN_SHIFT;

        return dsts;
}

/**
 * s3c_hsotg_handle_rx - RX FIFO has data
 * @hsotg: The device instance
 *
 * The IRQ handler has detected that the RX FIFO has some data in it
 * that requires processing, so find out what is in there and do the
 * appropriate read.
 *
 * The RXFIFO is a true FIFO, the packets coming out are still in packet
 * chunks, so if you have x packets received on an endpoint you'll get x
 * FIFO events delivered, each with a packet's worth of data in it.
 *
 * When using DMA, we should not be processing events from the RXFIFO
 * as the actual data should be sent to the memory directly and we turn
 * on the completion interrupts to get notifications of transfer completion.
 */
static void s3c_hsotg_handle_rx(struct s3c_hsotg *hsotg)
{
        u32 grxstsr = readl(hsotg->regs + S3C_GRXSTSP);
        u32 epnum, status, size;

        WARN_ON(using_dma(hsotg));

        epnum = grxstsr & S3C_GRXSTS_EPNum_MASK;
        status = grxstsr & S3C_GRXSTS_PktSts_MASK;

        size = grxstsr & S3C_GRXSTS_ByteCnt_MASK;
        size >>= S3C_GRXSTS_ByteCnt_SHIFT;

        if (1)
                dev_dbg(hsotg->dev, "%s: GRXSTSP=0x%08x (%d@%d)\n",
                        __func__, grxstsr, size, epnum);

#define __status(x) ((x) >> S3C_GRXSTS_PktSts_SHIFT)

        switch (status >> S3C_GRXSTS_PktSts_SHIFT) {
        case __status(S3C_GRXSTS_PktSts_GlobalOutNAK):
                dev_dbg(hsotg->dev, "GlobalOutNAK\n");
                break;

        case __status(S3C_GRXSTS_PktSts_OutDone):
                dev_dbg(hsotg->dev, "OutDone (Frame=0x%08x)\n",
                        s3c_hsotg_read_frameno(hsotg));

                if (!using_dma(hsotg))
                        s3c_hsotg_handle_outdone(hsotg, epnum, false);
                break;

        case __status(S3C_GRXSTS_PktSts_SetupDone):
                dev_dbg(hsotg->dev,
                        "SetupDone (Frame=0x%08x, DOPEPCTL=0x%08x)\n",
                        s3c_hsotg_read_frameno(hsotg),
                        readl(hsotg->regs + S3C_DOEPCTL(0)));

                s3c_hsotg_handle_outdone(hsotg, epnum, true);
                break;

        case __status(S3C_GRXSTS_PktSts_OutRX):
                s3c_hsotg_rx_data(hsotg, epnum, size);
                break;

        case __status(S3C_GRXSTS_PktSts_SetupRX):
                dev_dbg(hsotg->dev,
                        "SetupRX (Frame=0x%08x, DOPEPCTL=0x%08x)\n",
                        s3c_hsotg_read_frameno(hsotg),
                        readl(hsotg->regs + S3C_DOEPCTL(0)));

                s3c_hsotg_rx_data(hsotg, epnum, size);
                break;

        default:
                dev_warn(hsotg->dev, "%s: unknown status %08x\n",
                         __func__, grxstsr);

                s3c_hsotg_dump(hsotg);
                break;
        }
}

/**
 * s3c_hsotg_ep0_mps - turn max packet size into register setting
 * @mps: The maximum packet size in bytes.
*/
static u32 s3c_hsotg_ep0_mps(unsigned int mps)
{
        switch (mps) {
        case 64:
                return S3C_D0EPCTL_MPS_64;
        case 32:
                return S3C_D0EPCTL_MPS_32;
        case 16:
                return S3C_D0EPCTL_MPS_16;
        case 8:
                return S3C_D0EPCTL_MPS_8;
        }

        /* bad max packet size, warn and return invalid result */
        WARN_ON(1);
        return (u32)-1;
}

/**
 * s3c_hsotg_set_ep_maxpacket - set endpoint's max-packet field
 * @hsotg: The driver state.
 * @ep: The index number of the endpoint
 * @mps: The maximum packet size in bytes
 *
 * Configure the maximum packet size for the given endpoint, updating
 * the hardware control registers to reflect this.
 */
static void s3c_hsotg_set_ep_maxpacket(struct s3c_hsotg *hsotg,
                                       unsigned int ep, unsigned int mps)
{
        struct s3c_hsotg_ep *hs_ep = &hsotg->eps[ep];
        void __iomem *regs = hsotg->regs;
        u32 mpsval;
        u32 reg;

        if (ep == 0) {
                /* EP0 is a special case */
                mpsval = s3c_hsotg_ep0_mps(mps);
                if (mpsval > 3)
                        goto bad_mps;
        } else {
                if (mps >= S3C_DxEPCTL_MPS_LIMIT+1)
                        goto bad_mps;

                mpsval = mps;
        }

        hs_ep->ep.maxpacket = mps;

        /* update both the in and out endpoint controldir_ registers, even
         * if one of the directions may not be in use. */

        reg = readl(regs + S3C_DIEPCTL(ep));
        reg &= ~S3C_DxEPCTL_MPS_MASK;
        reg |= mpsval;
        writel(reg, regs + S3C_DIEPCTL(ep));

        reg = readl(regs + S3C_DOEPCTL(ep));
        reg &= ~S3C_DxEPCTL_MPS_MASK;
        reg |= mpsval;
        writel(reg, regs + S3C_DOEPCTL(ep));

        return;

bad_mps:
        dev_err(hsotg->dev, "ep%d: bad mps of %d\n", ep, mps);
}


/**
 * s3c_hsotg_trytx - check to see if anything needs transmitting
 * @hsotg: The driver state
 * @hs_ep: The driver endpoint to check.
 *
 * Check to see if there is a request that has data to send, and if so
 * make an attempt to write data into the FIFO.
 */
static int s3c_hsotg_trytx(struct s3c_hsotg *hsotg,
                           struct s3c_hsotg_ep *hs_ep)
{
        struct s3c_hsotg_req *hs_req = hs_ep->req;

        if (!hs_ep->dir_in || !hs_req)
                return 0;

        if (hs_req->req.actual < hs_req->req.length) {
                dev_dbg(hsotg->dev, "trying to write more for ep%d\n",
                        hs_ep->index);
                return s3c_hsotg_write_fifo(hsotg, hs_ep, hs_req);
        }

        return 0;
}

/**
 * s3c_hsotg_complete_in - complete IN transfer
 * @hsotg: The device state.
 * @hs_ep: The endpoint that has just completed.
 *
 * An IN transfer has been completed, update the transfer's state and then
 * call the relevant completion routines.
 */
static void s3c_hsotg_complete_in(struct s3c_hsotg *hsotg,
                                  struct s3c_hsotg_ep *hs_ep)
{
        struct s3c_hsotg_req *hs_req = hs_ep->req;
        u32 epsize = readl(hsotg->regs + S3C_DIEPTSIZ(hs_ep->index));
        int size_left, size_done;

        if (!hs_req) {
                dev_dbg(hsotg->dev, "XferCompl but no req\n");
                return;
        }

        /* Calculate the size of the transfer by checking how much is left
         * in the endpoint size register and then working it out from
         * the amount we loaded for the transfer.
         *
         * We do this even for DMA, as the transfer may have incremented
         * past the end of the buffer (DMA transfers are always 32bit
         * aligned).
         */

        size_left = S3C_DxEPTSIZ_XferSize_GET(epsize);

        size_done = hs_ep->size_loaded - size_left;
        size_done += hs_ep->last_load;

        if (hs_req->req.actual != size_done)
                dev_dbg(hsotg->dev, "%s: adjusting size done %d => %d\n",
                        __func__, hs_req->req.actual, size_done);

        hs_req->req.actual = size_done;

        /* if we did all of the transfer, and there is more data left
         * around, then try restarting the rest of the request */

        if (!size_left && hs_req->req.actual < hs_req->req.length) {
                dev_dbg(hsotg->dev, "%s trying more for req...\n", __func__);
                s3c_hsotg_start_req(hsotg, hs_ep, hs_req, true);
        } else
                s3c_hsotg_complete_request_lock(hsotg, hs_ep, hs_req, 0);
}

/**
 * s3c_hsotg_epint - handle an in/out endpoint interrupt
 * @hsotg: The driver state
 * @idx: The index for the endpoint (0..15)
 * @dir_in: Set if this is an IN endpoint
 *
 * Process and clear any interrupt pending for an individual endpoint
*/
static void s3c_hsotg_epint(struct s3c_hsotg *hsotg, unsigned int idx,
                            int dir_in)
{
        struct s3c_hsotg_ep *hs_ep = &hsotg->eps[idx];
        u32 epint_reg = dir_in ? S3C_DIEPINT(idx) : S3C_DOEPINT(idx);
        u32 epctl_reg = dir_in ? S3C_DIEPCTL(idx) : S3C_DOEPCTL(idx);
        u32 epsiz_reg = dir_in ? S3C_DIEPTSIZ(idx) : S3C_DOEPTSIZ(idx);
        u32 ints;
        u32 clear = 0;

        ints = readl(hsotg->regs + epint_reg);

        dev_dbg(hsotg->dev, "%s: ep%d(%s) DxEPINT=0x%08x\n",
                __func__, idx, dir_in ? "in" : "out", ints);

        if (ints & S3C_DxEPINT_XferCompl) {
                dev_dbg(hsotg->dev,
                        "%s: XferCompl: DxEPCTL=0x%08x, DxEPTSIZ=%08x\n",
                        __func__, readl(hsotg->regs + epctl_reg),
                        readl(hsotg->regs + epsiz_reg));

                /* we get OutDone from the FIFO, so we only need to look
                 * at completing IN requests here */
                if (dir_in) {
                        s3c_hsotg_complete_in(hsotg, hs_ep);

                        if (idx == 0 && !hs_ep->req)
                                s3c_hsotg_enqueue_setup(hsotg);
                } else if (using_dma(hsotg)) {
                        /* We're using DMA, we need to fire an OutDone here
                         * as we ignore the RXFIFO. */

                        s3c_hsotg_handle_outdone(hsotg, idx, false);
                }

                clear |= S3C_DxEPINT_XferCompl;
        }

        if (ints & S3C_DxEPINT_EPDisbld) {
                dev_dbg(hsotg->dev, "%s: EPDisbld\n", __func__);
                clear |= S3C_DxEPINT_EPDisbld;
        }

        if (ints & S3C_DxEPINT_AHBErr) {
                dev_dbg(hsotg->dev, "%s: AHBErr\n", __func__);
                clear |= S3C_DxEPINT_AHBErr;
        }

        if (ints & S3C_DxEPINT_Setup) {  /* Setup or Timeout */
                dev_dbg(hsotg->dev, "%s: Setup/Timeout\n",  __func__);

                if (using_dma(hsotg) && idx == 0) {
                        /* this is the notification we've received a
                         * setup packet. In non-DMA mode we'd get this
                         * from the RXFIFO, instead we need to process
                         * the setup here. */

                        if (dir_in)
                                WARN_ON_ONCE(1);
                        else
                                s3c_hsotg_handle_outdone(hsotg, 0, true);
                }

                clear |= S3C_DxEPINT_Setup;
        }

        if (ints & S3C_DxEPINT_Back2BackSetup) {
                dev_dbg(hsotg->dev, "%s: B2BSetup/INEPNakEff\n", __func__);
                clear |= S3C_DxEPINT_Back2BackSetup;
        }

        if (dir_in) {
                /* not sure if this is important, but we'll clear it anyway
                 */
                if (ints & S3C_DIEPMSK_INTknTXFEmpMsk) {
                        dev_dbg(hsotg->dev, "%s: ep%d: INTknTXFEmpMsk\n",
                                __func__, idx);
                        clear |= S3C_DIEPMSK_INTknTXFEmpMsk;
                }

                /* this probably means something bad is happening */
                if (ints & S3C_DIEPMSK_INTknEPMisMsk) {
                        dev_warn(hsotg->dev, "%s: ep%d: INTknEP\n",
                                 __func__, idx);
                        clear |= S3C_DIEPMSK_INTknEPMisMsk;
                }

                /* FIFO has space or is empty (see GAHBCFG) */
                if (hsotg->dedicated_fifos &&
                    ints & S3C_DIEPMSK_TxFIFOEmpty) {
                        dev_dbg(hsotg->dev, "%s: ep%d: TxFIFOEmpty\n",
                                __func__, idx);
                        s3c_hsotg_trytx(hsotg, hs_ep);
                        clear |= S3C_DIEPMSK_TxFIFOEmpty;
                }
        }

        writel(clear, hsotg->regs + epint_reg);
}

/**
 * s3c_hsotg_irq_enumdone - Handle EnumDone interrupt (enumeration done)
 * @hsotg: The device state.
 *
 * Handle updating the device settings after the enumeration phase has
 * been completed.
*/
static void s3c_hsotg_irq_enumdone(struct s3c_hsotg *hsotg)
{
        u32 dsts = readl(hsotg->regs + S3C_DSTS);
        int ep0_mps = 0, ep_mps;

        /* This should signal the finish of the enumeration phase
         * of the USB handshaking, so we should now know what rate
         * we connected at. */

        dev_dbg(hsotg->dev, "EnumDone (DSTS=0x%08x)\n", dsts);

        /* note, since we're limited by the size of transfer on EP0, and
         * it seems IN transfers must be a even number of packets we do
         * not advertise a 64byte MPS on EP0. */

        /* catch both EnumSpd_FS and EnumSpd_FS48 */
        switch (dsts & S3C_DSTS_EnumSpd_MASK) {
        case S3C_DSTS_EnumSpd_FS:
        case S3C_DSTS_EnumSpd_FS48:
                hsotg->gadget.speed = USB_SPEED_FULL;
                dev_info(hsotg->dev, "new device is full-speed\n");

                ep0_mps = EP0_MPS_LIMIT;
                ep_mps = 64;
                break;

        case S3C_DSTS_EnumSpd_HS:
                dev_info(hsotg->dev, "new device is high-speed\n");
                hsotg->gadget.speed = USB_SPEED_HIGH;

                ep0_mps = EP0_MPS_LIMIT;
                ep_mps = 512;
                break;

        case S3C_DSTS_EnumSpd_LS:
                hsotg->gadget.speed = USB_SPEED_LOW;
                dev_info(hsotg->dev, "new device is low-speed\n");

                /* note, we don't actually support LS in this driver at the
                 * moment, and the documentation seems to imply that it isn't
                 * supported by the PHYs on some of the devices.
                 */
                break;
        }

        /* we should now know the maximum packet size for an
         * endpoint, so set the endpoints to a default value. */

        if (ep0_mps) {
                int i;
                s3c_hsotg_set_ep_maxpacket(hsotg, 0, ep0_mps);
                for (i = 1; i < S3C_HSOTG_EPS; i++)
                        s3c_hsotg_set_ep_maxpacket(hsotg, i, ep_mps);
        }

        /* ensure after enumeration our EP0 is active */

        s3c_hsotg_enqueue_setup(hsotg);

        dev_dbg(hsotg->dev, "EP0: DIEPCTL0=0x%08x, DOEPCTL0=0x%08x\n",
                readl(hsotg->regs + S3C_DIEPCTL0),
                readl(hsotg->regs + S3C_DOEPCTL0));
}

/**
 * kill_all_requests - remove all requests from the endpoint's queue
 * @hsotg: The device state.
 * @ep: The endpoint the requests may be on.
 * @result: The result code to use.
 * @force: Force removal of any current requests
 *
 * Go through the requests on the given endpoint and mark them
 * completed with the given result code.
 */
static void kill_all_requests(struct s3c_hsotg *hsotg,
                              struct s3c_hsotg_ep *ep,
                              int result, bool force)
{
        struct s3c_hsotg_req *req, *treq;
        unsigned long flags;

        spin_lock_irqsave(&ep->lock, flags);

        list_for_each_entry_safe(req, treq, &ep->queue, queue) {
                /* currently, we can't do much about an already
                 * running request on an in endpoint */

                if (ep->req == req && ep->dir_in && !force)
                        continue;

                s3c_hsotg_complete_request(hsotg, ep, req,
                                           result);
        }

        spin_unlock_irqrestore(&ep->lock, flags);
}

#define call_gadget(_hs, _entry) \
        if ((_hs)->gadget.speed != USB_SPEED_UNKNOWN && \
            (_hs)->driver && (_hs)->driver->_entry)     \
                (_hs)->driver->_entry(&(_hs)->gadget);

/**
 * s3c_hsotg_disconnect_irq - disconnect irq service
 * @hsotg: The device state.
 *
 * A disconnect IRQ has been received, meaning that the host has
 * lost contact with the bus. Remove all current transactions
 * and signal the gadget driver that this has happened.
*/
static void s3c_hsotg_disconnect_irq(struct s3c_hsotg *hsotg)
{
        unsigned ep;

        for (ep = 0; ep < S3C_HSOTG_EPS; ep++)
                kill_all_requests(hsotg, &hsotg->eps[ep], -ESHUTDOWN, true);

        call_gadget(hsotg, disconnect);
}

/**
 * s3c_hsotg_irq_fifoempty - TX FIFO empty interrupt handler
 * @hsotg: The device state:
 * @periodic: True if this is a periodic FIFO interrupt
 */
static void s3c_hsotg_irq_fifoempty(struct s3c_hsotg *hsotg, bool periodic)
{
        struct s3c_hsotg_ep *ep;
        int epno, ret;

        /* look through for any more data to transmit */

        for (epno = 0; epno < S3C_HSOTG_EPS; epno++) {
                ep = &hsotg->eps[epno];

                if (!ep->dir_in)
                        continue;

                if ((periodic && !ep->periodic) ||
                    (!periodic && ep->periodic))
                        continue;

                ret = s3c_hsotg_trytx(hsotg, ep);
                if (ret < 0)
                        break;
        }
}

static struct s3c_hsotg *our_hsotg;

/* IRQ flags which will trigger a retry around the IRQ loop */
#define IRQ_RETRY_MASK (S3C_GINTSTS_NPTxFEmp | \
                        S3C_GINTSTS_PTxFEmp |  \
                        S3C_GINTSTS_RxFLvl)

/**
 * s3c_hsotg_irq - handle device interrupt
 * @irq: The IRQ number triggered
 * @pw: The pw value when registered the handler.
 */
static irqreturn_t s3c_hsotg_irq(int irq, void *pw)
{
        struct s3c_hsotg *hsotg = pw;
        int retry_count = 8;
        u32 gintsts;
        u32 gintmsk;

irq_retry:
        gintsts = readl(hsotg->regs + S3C_GINTSTS);
        gintmsk = readl(hsotg->regs + S3C_GINTMSK);

        dev_dbg(hsotg->dev, "%s: %08x %08x (%08x) retry %d\n",
                __func__, gintsts, gintsts & gintmsk, gintmsk, retry_count);

        gintsts &= gintmsk;

        if (gintsts & S3C_GINTSTS_OTGInt) {
                u32 otgint = readl(hsotg->regs + S3C_GOTGINT);

                dev_info(hsotg->dev, "OTGInt: %08x\n", otgint);

                writel(otgint, hsotg->regs + S3C_GOTGINT);
                writel(S3C_GINTSTS_OTGInt, hsotg->regs + S3C_GINTSTS);
        }

        if (gintsts & S3C_GINTSTS_DisconnInt) {
                dev_dbg(hsotg->dev, "%s: DisconnInt\n", __func__);
                writel(S3C_GINTSTS_DisconnInt, hsotg->regs + S3C_GINTSTS);

                s3c_hsotg_disconnect_irq(hsotg);
        }

        if (gintsts & S3C_GINTSTS_SessReqInt) {
                dev_dbg(hsotg->dev, "%s: SessReqInt\n", __func__);
                writel(S3C_GINTSTS_SessReqInt, hsotg->regs + S3C_GINTSTS);
        }

        if (gintsts & S3C_GINTSTS_EnumDone) {
                s3c_hsotg_irq_enumdone(hsotg);
                writel(S3C_GINTSTS_EnumDone, hsotg->regs + S3C_GINTSTS);
        }

        if (gintsts & S3C_GINTSTS_ConIDStsChng) {
                dev_dbg(hsotg->dev, "ConIDStsChg (DSTS=0x%08x, GOTCTL=%08x)\n",
                        readl(hsotg->regs + S3C_DSTS),
                        readl(hsotg->regs + S3C_GOTGCTL));

                writel(S3C_GINTSTS_ConIDStsChng, hsotg->regs + S3C_GINTSTS);
        }

        if (gintsts & (S3C_GINTSTS_OEPInt | S3C_GINTSTS_IEPInt)) {
                u32 daint = readl(hsotg->regs + S3C_DAINT);
                u32 daint_out = daint >> S3C_DAINT_OutEP_SHIFT;
                u32 daint_in = daint & ~(daint_out << S3C_DAINT_OutEP_SHIFT);
                int ep;

                dev_dbg(hsotg->dev, "%s: daint=%08x\n", __func__, daint);

                for (ep = 0; ep < 15 && daint_out; ep++, daint_out >>= 1) {
                        if (daint_out & 1)
                                s3c_hsotg_epint(hsotg, ep, 0);
                }

                for (ep = 0; ep < 15 && daint_in; ep++, daint_in >>= 1) {
                        if (daint_in & 1)
                                s3c_hsotg_epint(hsotg, ep, 1);
                }

                writel(daint, hsotg->regs + S3C_DAINT);
                writel(gintsts & (S3C_GINTSTS_OEPInt | S3C_GINTSTS_IEPInt),
                       hsotg->regs + S3C_GINTSTS);
        }

        if (gintsts & S3C_GINTSTS_USBRst) {
                dev_info(hsotg->dev, "%s: USBRst\n", __func__);
                dev_dbg(hsotg->dev, "GNPTXSTS=%08x\n",
                        readl(hsotg->regs + S3C_GNPTXSTS));

                kill_all_requests(hsotg, &hsotg->eps[0], -ECONNRESET, true);

                /* it seems after a reset we can end up with a situation
                 * where the TXFIFO still has data in it... the docs
                 * suggest resetting all the fifos, so use the init_fifo
                 * code to relayout and flush the fifos.
                 */

                s3c_hsotg_init_fifo(hsotg);

                s3c_hsotg_enqueue_setup(hsotg);

                writel(S3C_GINTSTS_USBRst, hsotg->regs + S3C_GINTSTS);
        }

        /* check both FIFOs */

        if (gintsts & S3C_GINTSTS_NPTxFEmp) {
                dev_dbg(hsotg->dev, "NPTxFEmp\n");

                /* Disable the interrupt to stop it happening again
                 * unless one of these endpoint routines decides that
                 * it needs re-enabling */

                s3c_hsotg_disable_gsint(hsotg, S3C_GINTSTS_NPTxFEmp);
                s3c_hsotg_irq_fifoempty(hsotg, false);

                writel(S3C_GINTSTS_NPTxFEmp, hsotg->regs + S3C_GINTSTS);
        }

        if (gintsts & S3C_GINTSTS_PTxFEmp) {
                dev_dbg(hsotg->dev, "PTxFEmp\n");

                /* See note in S3C_GINTSTS_NPTxFEmp */

                s3c_hsotg_disable_gsint(hsotg, S3C_GINTSTS_PTxFEmp);
                s3c_hsotg_irq_fifoempty(hsotg, true);

                writel(S3C_GINTSTS_PTxFEmp, hsotg->regs + S3C_GINTSTS);
        }

        if (gintsts & S3C_GINTSTS_RxFLvl) {
                /* note, since GINTSTS_RxFLvl doubles as FIFO-not-empty,
                 * we need to retry s3c_hsotg_handle_rx if this is still
                 * set. */

                s3c_hsotg_handle_rx(hsotg);
                writel(S3C_GINTSTS_RxFLvl, hsotg->regs + S3C_GINTSTS);
        }

        if (gintsts & S3C_GINTSTS_ModeMis) {
                dev_warn(hsotg->dev, "warning, mode mismatch triggered\n");
                writel(S3C_GINTSTS_ModeMis, hsotg->regs + S3C_GINTSTS);
        }

        if (gintsts & S3C_GINTSTS_USBSusp) {
                dev_info(hsotg->dev, "S3C_GINTSTS_USBSusp\n");
                writel(S3C_GINTSTS_USBSusp, hsotg->regs + S3C_GINTSTS);

                call_gadget(hsotg, suspend);
        }

        if (gintsts & S3C_GINTSTS_WkUpInt) {
                dev_info(hsotg->dev, "S3C_GINTSTS_WkUpIn\n");
                writel(S3C_GINTSTS_WkUpInt, hsotg->regs + S3C_GINTSTS);

                call_gadget(hsotg, resume);
        }

        if (gintsts & S3C_GINTSTS_ErlySusp) {
                dev_dbg(hsotg->dev, "S3C_GINTSTS_ErlySusp\n");
                writel(S3C_GINTSTS_ErlySusp, hsotg->regs + S3C_GINTSTS);
        }

        /* these next two seem to crop-up occasionally causing the core
         * to shutdown the USB transfer, so try clearing them and logging
         * the occurrence. */

        if (gintsts & S3C_GINTSTS_GOUTNakEff) {
                dev_info(hsotg->dev, "GOUTNakEff triggered\n");

                s3c_hsotg_dump(hsotg);

                writel(S3C_DCTL_CGOUTNak, hsotg->regs + S3C_DCTL);
                writel(S3C_GINTSTS_GOUTNakEff, hsotg->regs + S3C_GINTSTS);
        }

        if (gintsts & S3C_GINTSTS_GINNakEff) {
                dev_info(hsotg->dev, "GINNakEff triggered\n");

                s3c_hsotg_dump(hsotg);

                writel(S3C_DCTL_CGNPInNAK, hsotg->regs + S3C_DCTL);
                writel(S3C_GINTSTS_GINNakEff, hsotg->regs + S3C_GINTSTS);
        }

        /* if we've had fifo events, we should try and go around the
         * loop again to see if there's any point in returning yet. */

        if (gintsts & IRQ_RETRY_MASK && --retry_count > 0)
                        goto irq_retry;

        return IRQ_HANDLED;
}

/**
 * s3c_hsotg_ep_enable - enable the given endpoint
 * @ep: The USB endpint to configure
 * @desc: The USB endpoint descriptor to configure with.
 *
 * This is called from the USB gadget code's usb_ep_enable().
*/
static int s3c_hsotg_ep_enable(struct usb_ep *ep,
                               const struct usb_endpoint_descriptor *desc)
{
        struct s3c_hsotg_ep *hs_ep = our_ep(ep);
        struct s3c_hsotg *hsotg = hs_ep->parent;
        unsigned long flags;
        int index = hs_ep->index;
        u32 epctrl_reg;
        u32 epctrl;
        u32 mps;
        int dir_in;
        int ret = 0;

        dev_dbg(hsotg->dev,
                "%s: ep %s: a 0x%02x, attr 0x%02x, mps 0x%04x, intr %d\n",
                __func__, ep->name, desc->bEndpointAddress, desc->bmAttributes,
                desc->wMaxPacketSize, desc->bInterval);

        /* not to be called for EP0 */
        WARN_ON(index == 0);

        dir_in = (desc->bEndpointAddress & USB_ENDPOINT_DIR_MASK) ? 1 : 0;
        if (dir_in != hs_ep->dir_in) {
                dev_err(hsotg->dev, "%s: direction mismatch!\n", __func__);
                return -EINVAL;
        }

        mps = le16_to_cpu(desc->wMaxPacketSize);

        /* note, we handle this here instead of s3c_hsotg_set_ep_maxpacket */

        epctrl_reg = dir_in ? S3C_DIEPCTL(index) : S3C_DOEPCTL(index);
        epctrl = readl(hsotg->regs + epctrl_reg);

        dev_dbg(hsotg->dev, "%s: read DxEPCTL=0x%08x from 0x%08x\n",
                __func__, epctrl, epctrl_reg);

        spin_lock_irqsave(&hs_ep->lock, flags);

        epctrl &= ~(S3C_DxEPCTL_EPType_MASK | S3C_DxEPCTL_MPS_MASK);
        epctrl |= S3C_DxEPCTL_MPS(mps);

        /* mark the endpoint as active, otherwise the core may ignore
         * transactions entirely for this endpoint */
        epctrl |= S3C_DxEPCTL_USBActEp;

        /* set the NAK status on the endpoint, otherwise we might try and
         * do something with data that we've yet got a request to process
         * since the RXFIFO will take data for an endpoint even if the
         * size register hasn't been set.
         */

        epctrl |= S3C_DxEPCTL_SNAK;

        /* update the endpoint state */
        hs_ep->ep.maxpacket = mps;

        /* default, set to non-periodic */
        hs_ep->periodic = 0;

        switch (desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) {
        case USB_ENDPOINT_XFER_ISOC:
                dev_err(hsotg->dev, "no current ISOC support\n");
                ret = -EINVAL;
                goto out;

        case USB_ENDPOINT_XFER_BULK:
                epctrl |= S3C_DxEPCTL_EPType_Bulk;
                break;

        case USB_ENDPOINT_XFER_INT:
                if (dir_in) {
                        /* Allocate our TxFNum by simply using the index
                         * of the endpoint for the moment. We could do
                         * something better if the host indicates how
                         * many FIFOs we are expecting to use. */

                        hs_ep->periodic = 1;
                        epctrl |= S3C_DxEPCTL_TxFNum(index);
                }

                epctrl |= S3C_DxEPCTL_EPType_Intterupt;
                break;

        case USB_ENDPOINT_XFER_CONTROL:
                epctrl |= S3C_DxEPCTL_EPType_Control;
                break;
        }

        /* if the hardware has dedicated fifos, we must give each IN EP
         * a unique tx-fifo even if it is non-periodic.
         */
        if (dir_in && hsotg->dedicated_fifos)
                epctrl |= S3C_DxEPCTL_TxFNum(index);

        /* for non control endpoints, set PID to D0 */
        if (index)
                epctrl |= S3C_DxEPCTL_SetD0PID;

        dev_dbg(hsotg->dev, "%s: write DxEPCTL=0x%08x\n",
                __func__, epctrl);

        writel(epctrl, hsotg->regs + epctrl_reg);
        dev_dbg(hsotg->dev, "%s: read DxEPCTL=0x%08x\n",
                __func__, readl(hsotg->regs + epctrl_reg));

        /* enable the endpoint interrupt */
        s3c_hsotg_ctrl_epint(hsotg, index, dir_in, 1);

out:
        spin_unlock_irqrestore(&hs_ep->lock, flags);
        return ret;
}

static int s3c_hsotg_ep_disable(struct usb_ep *ep)
{
        struct s3c_hsotg_ep *hs_ep = our_ep(ep);
        struct s3c_hsotg *hsotg = hs_ep->parent;
        int dir_in = hs_ep->dir_in;
        int index = hs_ep->index;
        unsigned long flags;
        u32 epctrl_reg;
        u32 ctrl;

        dev_info(hsotg->dev, "%s(ep %p)\n", __func__, ep);

        if (ep == &hsotg->eps[0].ep) {
                dev_err(hsotg->dev, "%s: called for ep0\n", __func__);
                return -EINVAL;
        }

        epctrl_reg = dir_in ? S3C_DIEPCTL(index) : S3C_DOEPCTL(index);

        /* terminate all requests with shutdown */
        kill_all_requests(hsotg, hs_ep, -ESHUTDOWN, false);

        spin_lock_irqsave(&hs_ep->lock, flags);

        ctrl = readl(hsotg->regs + epctrl_reg);
        ctrl &= ~S3C_DxEPCTL_EPEna;
        ctrl &= ~S3C_DxEPCTL_USBActEp;
        ctrl |= S3C_DxEPCTL_SNAK;

        dev_dbg(hsotg->dev, "%s: DxEPCTL=0x%08x\n", __func__, ctrl);
        writel(ctrl, hsotg->regs + epctrl_reg);

        /* disable endpoint interrupts */
        s3c_hsotg_ctrl_epint(hsotg, hs_ep->index, hs_ep->dir_in, 0);

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

/**
 * on_list - check request is on the given endpoint
 * @ep: The endpoint to check.
 * @test: The request to test if it is on the endpoint.
*/
static bool on_list(struct s3c_hsotg_ep *ep, struct s3c_hsotg_req *test)
{
        struct s3c_hsotg_req *req, *treq;

        list_for_each_entry_safe(req, treq, &ep->queue, queue) {
                if (req == test)
                        return true;
        }

        return false;
}

static int s3c_hsotg_ep_dequeue(struct usb_ep *ep, struct usb_request *req)
{
        struct s3c_hsotg_req *hs_req = our_req(req);
        struct s3c_hsotg_ep *hs_ep = our_ep(ep);
        struct s3c_hsotg *hs = hs_ep->parent;
        unsigned long flags;

        dev_info(hs->dev, "ep_dequeue(%p,%p)\n", ep, req);

        if (hs_req == hs_ep->req) {
                dev_dbg(hs->dev, "%s: already in progress\n", __func__);
                return -EINPROGRESS;
        }

        spin_lock_irqsave(&hs_ep->lock, flags);

        if (!on_list(hs_ep, hs_req)) {
                spin_unlock_irqrestore(&hs_ep->lock, flags);
                return -EINVAL;
        }

        s3c_hsotg_complete_request(hs, hs_ep, hs_req, -ECONNRESET);
        spin_unlock_irqrestore(&hs_ep->lock, flags);

        return 0;
}

static int s3c_hsotg_ep_sethalt(struct usb_ep *ep, int value)
{
        struct s3c_hsotg_ep *hs_ep = our_ep(ep);
        struct s3c_hsotg *hs = hs_ep->parent;
        int index = hs_ep->index;
        unsigned long irqflags;
        u32 epreg;
        u32 epctl;

        dev_info(hs->dev, "%s(ep %p %s, %d)\n", __func__, ep, ep->name, value);

        spin_lock_irqsave(&hs_ep->lock, irqflags);

        /* write both IN and OUT control registers */

        epreg = S3C_DIEPCTL(index);
        epctl = readl(hs->regs + epreg);

        if (value)
                epctl |= S3C_DxEPCTL_Stall;
        else
                epctl &= ~S3C_DxEPCTL_Stall;

        writel(epctl, hs->regs + epreg);

        epreg = S3C_DOEPCTL(index);
        epctl = readl(hs->regs + epreg);

        if (value)
                epctl |= S3C_DxEPCTL_Stall;
        else
                epctl &= ~S3C_DxEPCTL_Stall;

        writel(epctl, hs->regs + epreg);

        spin_unlock_irqrestore(&hs_ep->lock, irqflags);

        return 0;
}

static struct usb_ep_ops s3c_hsotg_ep_ops = {
        .enable         = s3c_hsotg_ep_enable,
        .disable        = s3c_hsotg_ep_disable,
        .alloc_request  = s3c_hsotg_ep_alloc_request,
        .free_request   = s3c_hsotg_ep_free_request,
        .queue          = s3c_hsotg_ep_queue,
        .dequeue        = s3c_hsotg_ep_dequeue,
        .set_halt       = s3c_hsotg_ep_sethalt,
        /* note, don't believe we have any call for the fifo routines */
};

/**
 * s3c_hsotg_corereset - issue softreset to the core
 * @hsotg: The device state
 *
 * Issue a soft reset to the core, and await the core finishing it.
*/
static int s3c_hsotg_corereset(struct s3c_hsotg *hsotg)
{
        int timeout;
        u32 grstctl;

        dev_dbg(hsotg->dev, "resetting core\n");

        /* issue soft reset */
        writel(S3C_GRSTCTL_CSftRst, hsotg->regs + S3C_GRSTCTL);

        timeout = 1000;
        do {
                grstctl = readl(hsotg->regs + S3C_GRSTCTL);
        } while (!(grstctl & S3C_GRSTCTL_CSftRst) && timeout-- > 0);

        if (!(grstctl & S3C_GRSTCTL_CSftRst)) {
                dev_err(hsotg->dev, "Failed to get CSftRst asserted\n");
                return -EINVAL;
        }

        timeout = 1000;

        while (1) {
                u32 grstctl = readl(hsotg->regs + S3C_GRSTCTL);

                if (timeout-- < 0) {
                        dev_info(hsotg->dev,
                                 "%s: reset failed, GRSTCTL=%08x\n",
                                 __func__, grstctl);
                        return -ETIMEDOUT;
                }

                if (grstctl & S3C_GRSTCTL_CSftRst)
                        continue;

                if (!(grstctl & S3C_GRSTCTL_AHBIdle))
                        continue;

                break;          /* reset done */
        }

        dev_dbg(hsotg->dev, "reset successful\n");
        return 0;
}

int usb_gadget_probe_driver(struct usb_gadget_driver *driver,
                int (*bind)(struct usb_gadget *))
{
        struct s3c_hsotg *hsotg = our_hsotg;
        int ret;

        if (!hsotg) {
                printk(KERN_ERR "%s: called with no device\n", __func__);
                return -ENODEV;
        }

        if (!driver) {
                dev_err(hsotg->dev, "%s: no driver\n", __func__);
                return -EINVAL;
        }

        if (driver->speed != USB_SPEED_HIGH &&
            driver->speed != USB_SPEED_FULL) {
                dev_err(hsotg->dev, "%s: bad speed\n", __func__);
        }

        if (!bind || !driver->setup) {
                dev_err(hsotg->dev, "%s: missing entry points\n", __func__);
                return -EINVAL;
        }

        WARN_ON(hsotg->driver);

        driver->driver.bus = NULL;
        hsotg->driver = driver;
        hsotg->gadget.dev.driver = &driver->driver;
        hsotg->gadget.dev.dma_mask = hsotg->dev->dma_mask;
        hsotg->gadget.speed = USB_SPEED_UNKNOWN;

        ret = device_add(&hsotg->gadget.dev);
        if (ret) {
                dev_err(hsotg->dev, "failed to register gadget device\n");
                goto err;
        }

        ret = bind(&hsotg->gadget);
        if (ret) {
                dev_err(hsotg->dev, "failed bind %s\n", driver->driver.name);

                hsotg->gadget.dev.driver = NULL;
                hsotg->driver = NULL;
                goto err;
        }

        /* we must now enable ep0 ready for host detection and then
         * set configuration. */

        s3c_hsotg_corereset(hsotg);

        /* set the PLL on, remove the HNP/SRP and set the PHY */
        writel(S3C_GUSBCFG_PHYIf16 | S3C_GUSBCFG_TOutCal(7) |
               (0x5 << 10), hsotg->regs + S3C_GUSBCFG);

        /* looks like soft-reset changes state of FIFOs */
        s3c_hsotg_init_fifo(hsotg);

        __orr32(hsotg->regs + S3C_DCTL, S3C_DCTL_SftDiscon);

        writel(1 << 18 | S3C_DCFG_DevSpd_HS,  hsotg->regs + S3C_DCFG);

        writel(S3C_GINTSTS_DisconnInt | S3C_GINTSTS_SessReqInt |
               S3C_GINTSTS_ConIDStsChng | S3C_GINTSTS_USBRst |
               S3C_GINTSTS_EnumDone | S3C_GINTSTS_OTGInt |
               S3C_GINTSTS_USBSusp | S3C_GINTSTS_WkUpInt |
               S3C_GINTSTS_GOUTNakEff | S3C_GINTSTS_GINNakEff |
               S3C_GINTSTS_ErlySusp,
               hsotg->regs + S3C_GINTMSK);

        if (using_dma(hsotg))
                writel(S3C_GAHBCFG_GlblIntrEn | S3C_GAHBCFG_DMAEn |
                       S3C_GAHBCFG_HBstLen_Incr4,
                       hsotg->regs + S3C_GAHBCFG);
        else
                writel(S3C_GAHBCFG_GlblIntrEn, hsotg->regs + S3C_GAHBCFG);

        /* Enabling INTknTXFEmpMsk here seems to be a big mistake, we end
         * up being flooded with interrupts if the host is polling the
         * endpoint to try and read data. */

        writel(S3C_DIEPMSK_TimeOUTMsk | S3C_DIEPMSK_AHBErrMsk |
               S3C_DIEPMSK_INTknEPMisMsk |
               S3C_DIEPMSK_EPDisbldMsk | S3C_DIEPMSK_XferComplMsk |
               ((hsotg->dedicated_fifos) ? S3C_DIEPMSK_TxFIFOEmpty : 0),
               hsotg->regs + S3C_DIEPMSK);

        /* don't need XferCompl, we get that from RXFIFO in slave mode. In
         * DMA mode we may need this. */
        writel(S3C_DOEPMSK_SetupMsk | S3C_DOEPMSK_AHBErrMsk |
               S3C_DOEPMSK_EPDisbldMsk |
               (using_dma(hsotg) ? (S3C_DIEPMSK_XferComplMsk |
                                   S3C_DIEPMSK_TimeOUTMsk) : 0),
               hsotg->regs + S3C_DOEPMSK);

        writel(0, hsotg->regs + S3C_DAINTMSK);

        dev_info(hsotg->dev, "EP0: DIEPCTL0=0x%08x, DOEPCTL0=0x%08x\n",
                 readl(hsotg->regs + S3C_DIEPCTL0),
                 readl(hsotg->regs + S3C_DOEPCTL0));

        /* enable in and out endpoint interrupts */
        s3c_hsotg_en_gsint(hsotg, S3C_GINTSTS_OEPInt | S3C_GINTSTS_IEPInt);

        /* Enable the RXFIFO when in slave mode, as this is how we collect
         * the data. In DMA mode, we get events from the FIFO but also
         * things we cannot process, so do not use it. */
        if (!using_dma(hsotg))
                s3c_hsotg_en_gsint(hsotg, S3C_GINTSTS_RxFLvl);

        /* Enable interrupts for EP0 in and out */
        s3c_hsotg_ctrl_epint(hsotg, 0, 0, 1);
        s3c_hsotg_ctrl_epint(hsotg, 0, 1, 1);

        __orr32(hsotg->regs + S3C_DCTL, S3C_DCTL_PWROnPrgDone);
        udelay(10);  /* see openiboot */
        __bic32(hsotg->regs + S3C_DCTL, S3C_DCTL_PWROnPrgDone);

        dev_info(hsotg->dev, "DCTL=0x%08x\n", readl(hsotg->regs + S3C_DCTL));

        /* S3C_DxEPCTL_USBActEp says RO in manual, but seems to be set by
           writing to the EPCTL register.. */

        /* set to read 1 8byte packet */
        writel(S3C_DxEPTSIZ_MC(1) | S3C_DxEPTSIZ_PktCnt(1) |
               S3C_DxEPTSIZ_XferSize(8), hsotg->regs + DOEPTSIZ0);

        writel(s3c_hsotg_ep0_mps(hsotg->eps[0].ep.maxpacket) |
               S3C_DxEPCTL_CNAK | S3C_DxEPCTL_EPEna |
               S3C_DxEPCTL_USBActEp,
               hsotg->regs + S3C_DOEPCTL0);

        /* enable, but don't activate EP0in */
        writel(s3c_hsotg_ep0_mps(hsotg->eps[0].ep.maxpacket) |
               S3C_DxEPCTL_USBActEp, hsotg->regs + S3C_DIEPCTL0);

        s3c_hsotg_enqueue_setup(hsotg);

        dev_info(hsotg->dev, "EP0: DIEPCTL0=0x%08x, DOEPCTL0=0x%08x\n",
                 readl(hsotg->regs + S3C_DIEPCTL0),
                 readl(hsotg->regs + S3C_DOEPCTL0));

        /* clear global NAKs */
        writel(S3C_DCTL_CGOUTNak | S3C_DCTL_CGNPInNAK,
               hsotg->regs + S3C_DCTL);

        /* must be at-least 3ms to allow bus to see disconnect */
        msleep(3);

        /* remove the soft-disconnect and let's go */
        __bic32(hsotg->regs + S3C_DCTL, S3C_DCTL_SftDiscon);

        /* report to the user, and return */

        dev_info(hsotg->dev, "bound driver %s\n", driver->driver.name);
        return 0;

err:
        hsotg->driver = NULL;
        hsotg->gadget.dev.driver = NULL;
        return ret;
}
EXPORT_SYMBOL(usb_gadget_probe_driver);

int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
{
        struct s3c_hsotg *hsotg = our_hsotg;
        int ep;

        if (!hsotg)
                return -ENODEV;

        if (!driver || driver != hsotg->driver || !driver->unbind)
                return -EINVAL;

        /* all endpoints should be shutdown */
        for (ep = 0; ep < S3C_HSOTG_EPS; ep++)
                s3c_hsotg_ep_disable(&hsotg->eps[ep].ep);

        call_gadget(hsotg, disconnect);

        driver->unbind(&hsotg->gadget);
        hsotg->driver = NULL;
        hsotg->gadget.speed = USB_SPEED_UNKNOWN;

        device_del(&hsotg->gadget.dev);

        dev_info(hsotg->dev, "unregistered gadget driver '%s'\n",
                 driver->driver.name);

        return 0;
}
EXPORT_SYMBOL(usb_gadget_unregister_driver);

static int s3c_hsotg_gadget_getframe(struct usb_gadget *gadget)
{
        return s3c_hsotg_read_frameno(to_hsotg(gadget));
}

static struct usb_gadget_ops s3c_hsotg_gadget_ops = {
        .get_frame      = s3c_hsotg_gadget_getframe,
};

/**
 * s3c_hsotg_initep - initialise a single endpoint
 * @hsotg: The device state.
 * @hs_ep: The endpoint to be initialised.
 * @epnum: The endpoint number
 *
 * Initialise the given endpoint (as part of the probe and device state
 * creation) to give to the gadget driver. Setup the endpoint name, any
 * direction information and other state that may be required.
 */
static void __devinit s3c_hsotg_initep(struct s3c_hsotg *hsotg,
                                       struct s3c_hsotg_ep *hs_ep,
                                       int epnum)
{
        u32 ptxfifo;
        char *dir;

        if (epnum == 0)
                dir = "";
        else if ((epnum % 2) == 0) {
                dir = "out";
        } else {
                dir = "in";
                hs_ep->dir_in = 1;
        }

        hs_ep->index = epnum;

        snprintf(hs_ep->name, sizeof(hs_ep->name), "ep%d%s", epnum, dir);

        INIT_LIST_HEAD(&hs_ep->queue);
        INIT_LIST_HEAD(&hs_ep->ep.ep_list);

        spin_lock_init(&hs_ep->lock);

        /* add to the list of endpoints known by the gadget driver */
        if (epnum)
                list_add_tail(&hs_ep->ep.ep_list, &hsotg->gadget.ep_list);

        hs_ep->parent = hsotg;
        hs_ep->ep.name = hs_ep->name;
        hs_ep->ep.maxpacket = epnum ? 512 : EP0_MPS_LIMIT;
        hs_ep->ep.ops = &s3c_hsotg_ep_ops;

        /* Read the FIFO size for the Periodic TX FIFO, even if we're
         * an OUT endpoint, we may as well do this if in future the
         * code is changed to make each endpoint's direction changeable.
         */

        ptxfifo = readl(hsotg->regs + S3C_DPTXFSIZn(epnum));
        hs_ep->fifo_size = S3C_DPTXFSIZn_DPTxFSize_GET(ptxfifo) * 4;

        /* if we're using dma, we need to set the next-endpoint pointer
         * to be something valid.
         */

        if (using_dma(hsotg)) {
                u32 next = S3C_DxEPCTL_NextEp((epnum + 1) % 15);
                writel(next, hsotg->regs + S3C_DIEPCTL(epnum));
                writel(next, hsotg->regs + S3C_DOEPCTL(epnum));
        }
}

/**
 * s3c_hsotg_otgreset - reset the OtG phy block
 * @hsotg: The host state.
 *
 * Power up the phy, set the basic configuration and start the PHY.
 */
static void s3c_hsotg_otgreset(struct s3c_hsotg *hsotg)
{
        struct clk *xusbxti;
        u32 pwr, osc;

        pwr = readl(S3C_PHYPWR);
        pwr &= ~0x19;
        writel(pwr, S3C_PHYPWR);
        mdelay(1);

        osc = hsotg->plat->is_osc ? S3C_PHYCLK_EXT_OSC : 0;

        xusbxti = clk_get(hsotg->dev, "xusbxti");
        if (xusbxti && !IS_ERR(xusbxti)) {
                switch (clk_get_rate(xusbxti)) {
                case 12*MHZ:
                        osc |= S3C_PHYCLK_CLKSEL_12M;
                        break;
                case 24*MHZ:
                        osc |= S3C_PHYCLK_CLKSEL_24M;
                        break;
                default:
                case 48*MHZ:
                        /* default reference clock */
                        break;
                }
                clk_put(xusbxti);
        }

        writel(osc | 0x10, S3C_PHYCLK);

        /* issue a full set of resets to the otg and core */

        writel(S3C_RSTCON_PHY, S3C_RSTCON);
        udelay(20);     /* at-least 10uS */
        writel(0, S3C_RSTCON);
}


static void s3c_hsotg_init(struct s3c_hsotg *hsotg)
{
        u32 cfg4;

        /* unmask subset of endpoint interrupts */

        writel(S3C_DIEPMSK_TimeOUTMsk | S3C_DIEPMSK_AHBErrMsk |
               S3C_DIEPMSK_EPDisbldMsk | S3C_DIEPMSK_XferComplMsk,
               hsotg->regs + S3C_DIEPMSK);

        writel(S3C_DOEPMSK_SetupMsk | S3C_DOEPMSK_AHBErrMsk |
               S3C_DOEPMSK_EPDisbldMsk | S3C_DOEPMSK_XferComplMsk,
               hsotg->regs + S3C_DOEPMSK);

        writel(0, hsotg->regs + S3C_DAINTMSK);

        /* Be in disconnected state until gadget is registered */
        __orr32(hsotg->regs + S3C_DCTL, S3C_DCTL_SftDiscon);

        if (0) {
                /* post global nak until we're ready */
                writel(S3C_DCTL_SGNPInNAK | S3C_DCTL_SGOUTNak,
                       hsotg->regs + S3C_DCTL);
        }

        /* setup fifos */

        dev_info(hsotg->dev, "GRXFSIZ=0x%08x, GNPTXFSIZ=0x%08x\n",
                 readl(hsotg->regs + S3C_GRXFSIZ),
                 readl(hsotg->regs + S3C_GNPTXFSIZ));

        s3c_hsotg_init_fifo(hsotg);

        /* set the PLL on, remove the HNP/SRP and set the PHY */
        writel(S3C_GUSBCFG_PHYIf16 | S3C_GUSBCFG_TOutCal(7) | (0x5 << 10),
               hsotg->regs + S3C_GUSBCFG);

        writel(using_dma(hsotg) ? S3C_GAHBCFG_DMAEn : 0x0,
               hsotg->regs + S3C_GAHBCFG);

        /* check hardware configuration */

        cfg4 = readl(hsotg->regs + 0x50);
        hsotg->dedicated_fifos = (cfg4 >> 25) & 1;

        dev_info(hsotg->dev, "%s fifos\n",
                 hsotg->dedicated_fifos ? "dedicated" : "shared");
}

static void s3c_hsotg_dump(struct s3c_hsotg *hsotg)
{
        struct device *dev = hsotg->dev;
        void __iomem *regs = hsotg->regs;
        u32 val;
        int idx;

        dev_info(dev, "DCFG=0x%08x, DCTL=0x%08x, DIEPMSK=%08x\n",
                 readl(regs + S3C_DCFG), readl(regs + S3C_DCTL),
                 readl(regs + S3C_DIEPMSK));

        dev_info(dev, "GAHBCFG=0x%08x, 0x44=0x%08x\n",
                 readl(regs + S3C_GAHBCFG), readl(regs + 0x44));

        dev_info(dev, "GRXFSIZ=0x%08x, GNPTXFSIZ=0x%08x\n",
                 readl(regs + S3C_GRXFSIZ), readl(regs + S3C_GNPTXFSIZ));

        /* show periodic fifo settings */

        for (idx = 1; idx <= 15; idx++) {
                val = readl(regs + S3C_DPTXFSIZn(idx));
                dev_info(dev, "DPTx[%d] FSize=%d, StAddr=0x%08x\n", idx,
                         val >> S3C_DPTXFSIZn_DPTxFSize_SHIFT,
                         val & S3C_DPTXFSIZn_DPTxFStAddr_MASK);
        }

        for (idx = 0; idx < 15; idx++) {
                dev_info(dev,
                         "ep%d-in: EPCTL=0x%08x, SIZ=0x%08x, DMA=0x%08x\n", idx,
                         readl(regs + S3C_DIEPCTL(idx)),
                         readl(regs + S3C_DIEPTSIZ(idx)),
                         readl(regs + S3C_DIEPDMA(idx)));

                val = readl(regs + S3C_DOEPCTL(idx));
                dev_info(dev,
                         "ep%d-out: EPCTL=0x%08x, SIZ=0x%08x, DMA=0x%08x\n",
                         idx, readl(regs + S3C_DOEPCTL(idx)),
                         readl(regs + S3C_DOEPTSIZ(idx)),
                         readl(regs + S3C_DOEPDMA(idx)));

        }

        dev_info(dev, "DVBUSDIS=0x%08x, DVBUSPULSE=%08x\n",
                 readl(regs + S3C_DVBUSDIS), readl(regs + S3C_DVBUSPULSE));
}


/**
 * state_show - debugfs: show overall driver and device state.
 * @seq: The seq file to write to.
 * @v: Unused parameter.
 *
 * This debugfs entry shows the overall state of the hardware and
 * some general information about each of the endpoints available
 * to the system.
 */
static int state_show(struct seq_file *seq, void *v)
{
        struct s3c_hsotg *hsotg = seq->private;
        void __iomem *regs = hsotg->regs;
        int idx;

        seq_printf(seq, "DCFG=0x%08x, DCTL=0x%08x, DSTS=0x%08x\n",
                 readl(regs + S3C_DCFG),
                 readl(regs + S3C_DCTL),
                 readl(regs + S3C_DSTS));

        seq_printf(seq, "DIEPMSK=0x%08x, DOEPMASK=0x%08x\n",
                   readl(regs + S3C_DIEPMSK), readl(regs + S3C_DOEPMSK));

        seq_printf(seq, "GINTMSK=0x%08x, GINTSTS=0x%08x\n",
                   readl(regs + S3C_GINTMSK),
                   readl(regs + S3C_GINTSTS));

        seq_printf(seq, "DAINTMSK=0x%08x, DAINT=0x%08x\n",
                   readl(regs + S3C_DAINTMSK),
                   readl(regs + S3C_DAINT));

        seq_printf(seq, "GNPTXSTS=0x%08x, GRXSTSR=%08x\n",
                   readl(regs + S3C_GNPTXSTS),
                   readl(regs + S3C_GRXSTSR));

        seq_printf(seq, "\nEndpoint status:\n");

        for (idx = 0; idx < 15; idx++) {
                u32 in, out;

                in = readl(regs + S3C_DIEPCTL(idx));
                out = readl(regs + S3C_DOEPCTL(idx));

                seq_printf(seq, "ep%d: DIEPCTL=0x%08x, DOEPCTL=0x%08x",
                           idx, in, out);

                in = readl(regs + S3C_DIEPTSIZ(idx));
                out = readl(regs + S3C_DOEPTSIZ(idx));

                seq_printf(seq, ", DIEPTSIZ=0x%08x, DOEPTSIZ=0x%08x",
                           in, out);

                seq_printf(seq, "\n");
        }

        return 0;
}

static int state_open(struct inode *inode, struct file *file)
{
        return single_open(file, state_show, inode->i_private);
}

static const struct file_operations state_fops = {
        .owner          = THIS_MODULE,
        .open           = state_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

/**
 * fifo_show - debugfs: show the fifo information
 * @seq: The seq_file to write data to.
 * @v: Unused parameter.
 *
 * Show the FIFO information for the overall fifo and all the
 * periodic transmission FIFOs.
*/
static int fifo_show(struct seq_file *seq, void *v)
{
        struct s3c_hsotg *hsotg = seq->private;
        void __iomem *regs = hsotg->regs;
        u32 val;
        int idx;

        seq_printf(seq, "Non-periodic FIFOs:\n");
        seq_printf(seq, "RXFIFO: Size %d\n", readl(regs + S3C_GRXFSIZ));

        val = readl(regs + S3C_GNPTXFSIZ);
        seq_printf(seq, "NPTXFIFO: Size %d, Start 0x%08x\n",
                   val >> S3C_GNPTXFSIZ_NPTxFDep_SHIFT,
                   val & S3C_GNPTXFSIZ_NPTxFStAddr_MASK);

        seq_printf(seq, "\nPeriodic TXFIFOs:\n");

        for (idx = 1; idx <= 15; idx++) {
                val = readl(regs + S3C_DPTXFSIZn(idx));

                seq_printf(seq, "\tDPTXFIFO%2d: Size %d, Start 0x%08x\n", idx,
                           val >> S3C_DPTXFSIZn_DPTxFSize_SHIFT,
                           val & S3C_DPTXFSIZn_DPTxFStAddr_MASK);
        }

        return 0;
}

static int fifo_open(struct inode *inode, struct file *file)
{
        return single_open(file, fifo_show, inode->i_private);
}

static const struct file_operations fifo_fops = {
        .owner          = THIS_MODULE,
        .open           = fifo_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};


static const char *decode_direction(int is_in)
{
        return is_in ? "in" : "out";
}

/**
 * ep_show - debugfs: show the state of an endpoint.
 * @seq: The seq_file to write data to.
 * @v: Unused parameter.
 *
 * This debugfs entry shows the state of the given endpoint (one is
 * registered for each available).
*/
static int ep_show(struct seq_file *seq, void *v)
{
        struct s3c_hsotg_ep *ep = seq->private;
        struct s3c_hsotg *hsotg = ep->parent;
        struct s3c_hsotg_req *req;
        void __iomem *regs = hsotg->regs;
        int index = ep->index;
        int show_limit = 15;
        unsigned long flags;

        seq_printf(seq, "Endpoint index %d, named %s,  dir %s:\n",
                   ep->index, ep->ep.name, decode_direction(ep->dir_in));

        /* first show the register state */

        seq_printf(seq, "\tDIEPCTL=0x%08x, DOEPCTL=0x%08x\n",
                   readl(regs + S3C_DIEPCTL(index)),
                   readl(regs + S3C_DOEPCTL(index)));

        seq_printf(seq, "\tDIEPDMA=0x%08x, DOEPDMA=0x%08x\n",
                   readl(regs + S3C_DIEPDMA(index)),
                   readl(regs + S3C_DOEPDMA(index)));

        seq_printf(seq, "\tDIEPINT=0x%08x, DOEPINT=0x%08x\n",
                   readl(regs + S3C_DIEPINT(index)),
                   readl(regs + S3C_DOEPINT(index)));

        seq_printf(seq, "\tDIEPTSIZ=0x%08x, DOEPTSIZ=0x%08x\n",
                   readl(regs + S3C_DIEPTSIZ(index)),
                   readl(regs + S3C_DOEPTSIZ(index)));

        seq_printf(seq, "\n");
        seq_printf(seq, "mps %d\n", ep->ep.maxpacket);
        seq_printf(seq, "total_data=%ld\n", ep->total_data);

        seq_printf(seq, "request list (%p,%p):\n",
                   ep->queue.next, ep->queue.prev);

        spin_lock_irqsave(&ep->lock, flags);

        list_for_each_entry(req, &ep->queue, queue) {
                if (--show_limit < 0) {
                        seq_printf(seq, "not showing more requests...\n");
                        break;
                }

                seq_printf(seq, "%c req %p: %d bytes @%p, ",
                           req == ep->req ? '*' : ' ',
                           req, req->req.length, req->req.buf);
                seq_printf(seq, "%d done, res %d\n",
                           req->req.actual, req->req.status);
        }

        spin_unlock_irqrestore(&ep->lock, flags);

        return 0;
}

static int ep_open(struct inode *inode, struct file *file)
{
        return single_open(file, ep_show, inode->i_private);
}

static const struct file_operations ep_fops = {
        .owner          = THIS_MODULE,
        .open           = ep_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

/**
 * s3c_hsotg_create_debug - create debugfs directory and files
 * @hsotg: The driver state
 *
 * Create the debugfs files to allow the user to get information
 * about the state of the system. The directory name is created
 * with the same name as the device itself, in case we end up
 * with multiple blocks in future systems.
*/
static void __devinit s3c_hsotg_create_debug(struct s3c_hsotg *hsotg)
{
        struct dentry *root;
        unsigned epidx;

        root = debugfs_create_dir(dev_name(hsotg->dev), NULL);
        hsotg->debug_root = root;
        if (IS_ERR(root)) {
                dev_err(hsotg->dev, "cannot create debug root\n");
                return;
        }

        /* create general state file */

        hsotg->debug_file = debugfs_create_file("state", 0444, root,
                                                hsotg, &state_fops);

        if (IS_ERR(hsotg->debug_file))
                dev_err(hsotg->dev, "%s: failed to create state\n", __func__);

        hsotg->debug_fifo = debugfs_create_file("fifo", 0444, root,
                                                hsotg, &fifo_fops);

        if (IS_ERR(hsotg->debug_fifo))
                dev_err(hsotg->dev, "%s: failed to create fifo\n", __func__);

        /* create one file for each endpoint */

        for (epidx = 0; epidx < S3C_HSOTG_EPS; epidx++) {
                struct s3c_hsotg_ep *ep = &hsotg->eps[epidx];

                ep->debugfs = debugfs_create_file(ep->name, 0444,
                                                  root, ep, &ep_fops);

                if (IS_ERR(ep->debugfs))
                        dev_err(hsotg->dev, "failed to create %s debug file\n",
                                ep->name);
        }
}

/**
 * s3c_hsotg_delete_debug - cleanup debugfs entries
 * @hsotg: The driver state
 *
 * Cleanup (remove) the debugfs files for use on module exit.
*/
static void __devexit s3c_hsotg_delete_debug(struct s3c_hsotg *hsotg)
{
        unsigned epidx;

        for (epidx = 0; epidx < S3C_HSOTG_EPS; epidx++) {
                struct s3c_hsotg_ep *ep = &hsotg->eps[epidx];
                debugfs_remove(ep->debugfs);
        }

        debugfs_remove(hsotg->debug_file);
        debugfs_remove(hsotg->debug_fifo);
        debugfs_remove(hsotg->debug_root);
}

/**
 * s3c_hsotg_gate - set the hardware gate for the block
 * @pdev: The device we bound to
 * @on: On or off.
 *
 * Set the hardware gate setting into the block. If we end up on
 * something other than an S3C64XX, then we might need to change this
 * to using a platform data callback, or some other mechanism.
 */
static void s3c_hsotg_gate(struct platform_device *pdev, bool on)
{
        unsigned long flags;
        u32 others;

        local_irq_save(flags);

        others = __raw_readl(S3C64XX_OTHERS);
        if (on)
                others |= S3C64XX_OTHERS_USBMASK;
        else
                others &= ~S3C64XX_OTHERS_USBMASK;
        __raw_writel(others, S3C64XX_OTHERS);

        local_irq_restore(flags);
}

static struct s3c_hsotg_plat s3c_hsotg_default_pdata;

static int __devinit s3c_hsotg_probe(struct platform_device *pdev)
{
        struct s3c_hsotg_plat *plat = pdev->dev.platform_data;
        struct device *dev = &pdev->dev;
        struct s3c_hsotg *hsotg;
        struct resource *res;
        int epnum;
        int ret;

        if (!plat)
                plat = &s3c_hsotg_default_pdata;

        hsotg = kzalloc(sizeof(struct s3c_hsotg) +
                        sizeof(struct s3c_hsotg_ep) * S3C_HSOTG_EPS,
                        GFP_KERNEL);
        if (!hsotg) {
                dev_err(dev, "cannot get memory\n");
                return -ENOMEM;
        }

        hsotg->dev = dev;
        hsotg->plat = plat;

        hsotg->clk = clk_get(&pdev->dev, "otg");
        if (IS_ERR(hsotg->clk)) {
                dev_err(dev, "cannot get otg clock\n");
                ret = -EINVAL;
                goto err_mem;
        }

        platform_set_drvdata(pdev, hsotg);

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res) {
                dev_err(dev, "cannot find register resource 0\n");
                ret = -EINVAL;
                goto err_clk;
        }

        hsotg->regs_res = request_mem_region(res->start, resource_size(res),
                                             dev_name(dev));
        if (!hsotg->regs_res) {
                dev_err(dev, "cannot reserve registers\n");
                ret = -ENOENT;
                goto err_clk;
        }

        hsotg->regs = ioremap(res->start, resource_size(res));
        if (!hsotg->regs) {
                dev_err(dev, "cannot map registers\n");
                ret = -ENXIO;
                goto err_regs_res;
        }

        ret = platform_get_irq(pdev, 0);
        if (ret < 0) {
                dev_err(dev, "cannot find IRQ\n");
                goto err_regs;
        }

        hsotg->irq = ret;

        ret = request_irq(ret, s3c_hsotg_irq, 0, dev_name(dev), hsotg);
        if (ret < 0) {
                dev_err(dev, "cannot claim IRQ\n");
                goto err_regs;
        }

        dev_info(dev, "regs %p, irq %d\n", hsotg->regs, hsotg->irq);

        device_initialize(&hsotg->gadget.dev);

        dev_set_name(&hsotg->gadget.dev, "gadget");

        hsotg->gadget.is_dualspeed = 1;
        hsotg->gadget.ops = &s3c_hsotg_gadget_ops;
        hsotg->gadget.name = dev_name(dev);

        hsotg->gadget.dev.parent = dev;
        hsotg->gadget.dev.dma_mask = dev->dma_mask;

        /* setup endpoint information */

        INIT_LIST_HEAD(&hsotg->gadget.ep_list);
        hsotg->gadget.ep0 = &hsotg->eps[0].ep;

        /* allocate EP0 request */

        hsotg->ctrl_req = s3c_hsotg_ep_alloc_request(&hsotg->eps[0].ep,
                                                     GFP_KERNEL);
        if (!hsotg->ctrl_req) {
                dev_err(dev, "failed to allocate ctrl req\n");
                goto err_regs;
        }

        /* reset the system */

        clk_enable(hsotg->clk);

        s3c_hsotg_gate(pdev, true);

        s3c_hsotg_otgreset(hsotg);
        s3c_hsotg_corereset(hsotg);
        s3c_hsotg_init(hsotg);

        /* initialise the endpoints now the core has been initialised */
        for (epnum = 0; epnum < S3C_HSOTG_EPS; epnum++)
                s3c_hsotg_initep(hsotg, &hsotg->eps[epnum], epnum);

        s3c_hsotg_create_debug(hsotg);

        s3c_hsotg_dump(hsotg);

        our_hsotg = hsotg;
        return 0;

err_regs:
        iounmap(hsotg->regs);

err_regs_res:
        release_resource(hsotg->regs_res);
        kfree(hsotg->regs_res);
err_clk:
        clk_put(hsotg->clk);
err_mem:
        kfree(hsotg);
        return ret;
}

static int __devexit s3c_hsotg_remove(struct platform_device *pdev)
{
        struct s3c_hsotg *hsotg = platform_get_drvdata(pdev);

        s3c_hsotg_delete_debug(hsotg);

        usb_gadget_unregister_driver(hsotg->driver);

        free_irq(hsotg->irq, hsotg);
        iounmap(hsotg->regs);

        release_resource(hsotg->regs_res);
        kfree(hsotg->regs_res);

        s3c_hsotg_gate(pdev, false);

        clk_disable(hsotg->clk);
        clk_put(hsotg->clk);

        kfree(hsotg);
        return 0;
}

#if 1
#define s3c_hsotg_suspend NULL
#define s3c_hsotg_resume NULL
#endif

static struct platform_driver s3c_hsotg_driver = {
        .driver         = {
                .name   = "s3c-hsotg",
                .owner  = THIS_MODULE,
        },
        .probe          = s3c_hsotg_probe,
        .remove         = __devexit_p(s3c_hsotg_remove),
        .suspend        = s3c_hsotg_suspend,
        .resume         = s3c_hsotg_resume,
};

static int __init s3c_hsotg_modinit(void)
{
        return platform_driver_register(&s3c_hsotg_driver);
}

static void __exit s3c_hsotg_modexit(void)
{
        platform_driver_unregister(&s3c_hsotg_driver);
}

module_init(s3c_hsotg_modinit);
module_exit(s3c_hsotg_modexit);

MODULE_DESCRIPTION("Samsung S3C USB High-speed/OtG device");
MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:s3c-hsotg");