[PATCH] const struct tty_operations

[linux-2.6] / drivers / usb / gadget / net2280.c

/*
 * Driver for the PLX NET2280 USB device controller.
 * Specs and errata are available from <http://www.plxtech.com>.
 *
 * PLX Technology Inc. (formerly NetChip Technology) supported the
 * development of this driver.
 *
 *
 * CODE STATUS HIGHLIGHTS
 *
 * This driver should work well with most "gadget" drivers, including
 * the File Storage, Serial, and Ethernet/RNDIS gadget drivers
 * as well as Gadget Zero and Gadgetfs.
 *
 * DMA is enabled by default.  Drivers using transfer queues might use
 * DMA chaining to remove IRQ latencies between transfers.  (Except when
 * short OUT transfers happen.)  Drivers can use the req->no_interrupt
 * hint to completely eliminate some IRQs, if a later IRQ is guaranteed
 * and DMA chaining is enabled.
 *
 * Note that almost all the errata workarounds here are only needed for
 * rev1 chips.  Rev1a silicon (0110) fixes almost all of them.
 */

/*
 * Copyright (C) 2003 David Brownell
 * Copyright (C) 2003-2005 PLX Technology, Inc.
 *
 * Modified Seth Levy 2005 PLX Technology, Inc. to provide compatibility
 *      with 2282 chip
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#undef  DEBUG           /* messages on error and most fault paths */
#undef  VERBOSE         /* extra debug messages (success too) */

#include <linux/module.h>
#include <linux/pci.h>
#include <linux/dma-mapping.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/smp_lock.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/timer.h>
#include <linux/list.h>
#include <linux/interrupt.h>
#include <linux/moduleparam.h>
#include <linux/device.h>
#include <linux/usb_ch9.h>
#include <linux/usb_gadget.h>

#include <asm/byteorder.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/system.h>
#include <asm/unaligned.h>


#define DRIVER_DESC             "PLX NET228x USB Peripheral Controller"
#define DRIVER_VERSION          "2005 Sept 27"

#define DMA_ADDR_INVALID        (~(dma_addr_t)0)
#define EP_DONTUSE              13      /* nonzero */

#define USE_RDK_LEDS            /* GPIO pins control three LEDs */


static const char driver_name [] = "net2280";
static const char driver_desc [] = DRIVER_DESC;

static const char ep0name [] = "ep0";
static const char *const ep_name [] = {
        ep0name,
        "ep-a", "ep-b", "ep-c", "ep-d",
        "ep-e", "ep-f",
};

/* use_dma -- general goodness, fewer interrupts, less cpu load (vs PIO)
 * use_dma_chaining -- dma descriptor queueing gives even more irq reduction
 *
 * The net2280 DMA engines are not tightly integrated with their FIFOs;
 * not all cases are (yet) handled well in this driver or the silicon.
 * Some gadget drivers work better with the dma support here than others.
 * These two parameters let you use PIO or more aggressive DMA.
 */
static int use_dma = 1;
static int use_dma_chaining = 0;

/* "modprobe net2280 use_dma=n" etc */
module_param (use_dma, bool, S_IRUGO);
module_param (use_dma_chaining, bool, S_IRUGO);


/* mode 0 == ep-{a,b,c,d} 1K fifo each
 * mode 1 == ep-{a,b} 2K fifo each, ep-{c,d} unavailable
 * mode 2 == ep-a 2K fifo, ep-{b,c} 1K each, ep-d unavailable
 */
static ushort fifo_mode = 0;

/* "modprobe net2280 fifo_mode=1" etc */
module_param (fifo_mode, ushort, 0644);

/* enable_suspend -- When enabled, the driver will respond to
 * USB suspend requests by powering down the NET2280.  Otherwise,
 * USB suspend requests will be ignored.  This is acceptible for
 * self-powered devices
 */
static int enable_suspend = 0;

/* "modprobe net2280 enable_suspend=1" etc */
module_param (enable_suspend, bool, S_IRUGO);


#define DIR_STRING(bAddress) (((bAddress) & USB_DIR_IN) ? "in" : "out")

#if defined(CONFIG_USB_GADGET_DEBUG_FILES) || defined (DEBUG)
static char *type_string (u8 bmAttributes)
{
        switch ((bmAttributes) & USB_ENDPOINT_XFERTYPE_MASK) {
        case USB_ENDPOINT_XFER_BULK:    return "bulk";
        case USB_ENDPOINT_XFER_ISOC:    return "iso";
        case USB_ENDPOINT_XFER_INT:     return "intr";
        };
        return "control";
}
#endif

#include "net2280.h"

#define valid_bit       __constant_cpu_to_le32 (1 << VALID_BIT)
#define dma_done_ie     __constant_cpu_to_le32 (1 << DMA_DONE_INTERRUPT_ENABLE)

/*-------------------------------------------------------------------------*/

static int
net2280_enable (struct usb_ep *_ep, const struct usb_endpoint_descriptor *desc)
{
        struct net2280          *dev;
        struct net2280_ep       *ep;
        u32                     max, tmp;
        unsigned long           flags;

        ep = container_of (_ep, struct net2280_ep, ep);
        if (!_ep || !desc || ep->desc || _ep->name == ep0name
                        || desc->bDescriptorType != USB_DT_ENDPOINT)
                return -EINVAL;
        dev = ep->dev;
        if (!dev->driver || dev->gadget.speed == USB_SPEED_UNKNOWN)
                return -ESHUTDOWN;

        /* erratum 0119 workaround ties up an endpoint number */
        if ((desc->bEndpointAddress & 0x0f) == EP_DONTUSE)
                return -EDOM;

        /* sanity check ep-e/ep-f since their fifos are small */
        max = le16_to_cpu (desc->wMaxPacketSize) & 0x1fff;
        if (ep->num > 4 && max > 64)
                return -ERANGE;

        spin_lock_irqsave (&dev->lock, flags);
        _ep->maxpacket = max & 0x7ff;
        ep->desc = desc;

        /* ep_reset() has already been called */
        ep->stopped = 0;
        ep->out_overflow = 0;

        /* set speed-dependent max packet; may kick in high bandwidth */
        set_idx_reg (dev->regs, REG_EP_MAXPKT (dev, ep->num), max);

        /* FIFO lines can't go to different packets.  PIO is ok, so
         * use it instead of troublesome (non-bulk) multi-packet DMA.
         */
        if (ep->dma && (max % 4) != 0 && use_dma_chaining) {
                DEBUG (ep->dev, "%s, no dma for maxpacket %d\n",
                        ep->ep.name, ep->ep.maxpacket);
                ep->dma = NULL;
        }

        /* set type, direction, address; reset fifo counters */
        writel ((1 << FIFO_FLUSH), &ep->regs->ep_stat);
        tmp = (desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK);
        if (tmp == USB_ENDPOINT_XFER_INT) {
                /* erratum 0105 workaround prevents hs NYET */
                if (dev->chiprev == 0100
                                && dev->gadget.speed == USB_SPEED_HIGH
                                && !(desc->bEndpointAddress & USB_DIR_IN))
                        writel ((1 << CLEAR_NAK_OUT_PACKETS_MODE),
                                &ep->regs->ep_rsp);
        } else if (tmp == USB_ENDPOINT_XFER_BULK) {
                /* catch some particularly blatant driver bugs */
                if ((dev->gadget.speed == USB_SPEED_HIGH
                                        && max != 512)
                                || (dev->gadget.speed == USB_SPEED_FULL
                                        && max > 64)) {
                        spin_unlock_irqrestore (&dev->lock, flags);
                        return -ERANGE;
                }
        }
        ep->is_iso = (tmp == USB_ENDPOINT_XFER_ISOC) ? 1 : 0;
        tmp <<= ENDPOINT_TYPE;
        tmp |= desc->bEndpointAddress;
        tmp |= (4 << ENDPOINT_BYTE_COUNT);      /* default full fifo lines */
        tmp |= 1 << ENDPOINT_ENABLE;
        wmb ();

        /* for OUT transfers, block the rx fifo until a read is posted */
        ep->is_in = (tmp & USB_DIR_IN) != 0;
        if (!ep->is_in)
                writel ((1 << SET_NAK_OUT_PACKETS), &ep->regs->ep_rsp);
        else if (dev->pdev->device != 0x2280) {
                /* Added for 2282, Don't use nak packets on an in endpoint,
                 * this was ignored on 2280
                 */
                writel ((1 << CLEAR_NAK_OUT_PACKETS)
                        | (1 << CLEAR_NAK_OUT_PACKETS_MODE), &ep->regs->ep_rsp);
        }

        writel (tmp, &ep->regs->ep_cfg);

        /* enable irqs */
        if (!ep->dma) {                         /* pio, per-packet */
                tmp = (1 << ep->num) | readl (&dev->regs->pciirqenb0);
                writel (tmp, &dev->regs->pciirqenb0);

                tmp = (1 << DATA_PACKET_RECEIVED_INTERRUPT_ENABLE)
                        | (1 << DATA_PACKET_TRANSMITTED_INTERRUPT_ENABLE);
                if (dev->pdev->device == 0x2280)
                        tmp |= readl (&ep->regs->ep_irqenb);
                writel (tmp, &ep->regs->ep_irqenb);
        } else {                                /* dma, per-request */
                tmp = (1 << (8 + ep->num));     /* completion */
                tmp |= readl (&dev->regs->pciirqenb1);
                writel (tmp, &dev->regs->pciirqenb1);

                /* for short OUT transfers, dma completions can't
                 * advance the queue; do it pio-style, by hand.
                 * NOTE erratum 0112 workaround #2
                 */
                if ((desc->bEndpointAddress & USB_DIR_IN) == 0) {
                        tmp = (1 << SHORT_PACKET_TRANSFERRED_INTERRUPT_ENABLE);
                        writel (tmp, &ep->regs->ep_irqenb);

                        tmp = (1 << ep->num) | readl (&dev->regs->pciirqenb0);
                        writel (tmp, &dev->regs->pciirqenb0);
                }
        }

        tmp = desc->bEndpointAddress;
        DEBUG (dev, "enabled %s (ep%d%s-%s) %s max %04x\n",
                _ep->name, tmp & 0x0f, DIR_STRING (tmp),
                type_string (desc->bmAttributes),
                ep->dma ? "dma" : "pio", max);

        /* pci writes may still be posted */
        spin_unlock_irqrestore (&dev->lock, flags);
        return 0;
}

static int handshake (u32 __iomem *ptr, u32 mask, u32 done, int usec)
{
        u32     result;

        do {
                result = readl (ptr);
                if (result == ~(u32)0)          /* "device unplugged" */
                        return -ENODEV;
                result &= mask;
                if (result == done)
                        return 0;
                udelay (1);
                usec--;
        } while (usec > 0);
        return -ETIMEDOUT;
}

static const struct usb_ep_ops net2280_ep_ops;

static void ep_reset (struct net2280_regs __iomem *regs, struct net2280_ep *ep)
{
        u32             tmp;

        ep->desc = NULL;
        INIT_LIST_HEAD (&ep->queue);

        ep->ep.maxpacket = ~0;
        ep->ep.ops = &net2280_ep_ops;

        /* disable the dma, irqs, endpoint... */
        if (ep->dma) {
                writel (0, &ep->dma->dmactl);
                writel (  (1 << DMA_SCATTER_GATHER_DONE_INTERRUPT)
                        | (1 << DMA_TRANSACTION_DONE_INTERRUPT)
                        | (1 << DMA_ABORT)
                        , &ep->dma->dmastat);

                tmp = readl (&regs->pciirqenb0);
                tmp &= ~(1 << ep->num);
                writel (tmp, &regs->pciirqenb0);
        } else {
                tmp = readl (&regs->pciirqenb1);
                tmp &= ~(1 << (8 + ep->num));   /* completion */
                writel (tmp, &regs->pciirqenb1);
        }
        writel (0, &ep->regs->ep_irqenb);

        /* init to our chosen defaults, notably so that we NAK OUT
         * packets until the driver queues a read (+note erratum 0112)
         */
        if (!ep->is_in || ep->dev->pdev->device == 0x2280) {
                tmp = (1 << SET_NAK_OUT_PACKETS_MODE)
                | (1 << SET_NAK_OUT_PACKETS)
                | (1 << CLEAR_EP_HIDE_STATUS_PHASE)
                | (1 << CLEAR_INTERRUPT_MODE);
        } else {
                /* added for 2282 */
                tmp = (1 << CLEAR_NAK_OUT_PACKETS_MODE)
                | (1 << CLEAR_NAK_OUT_PACKETS)
                | (1 << CLEAR_EP_HIDE_STATUS_PHASE)
                | (1 << CLEAR_INTERRUPT_MODE);
        }

        if (ep->num != 0) {
                tmp |= (1 << CLEAR_ENDPOINT_TOGGLE)
                        | (1 << CLEAR_ENDPOINT_HALT);
        }
        writel (tmp, &ep->regs->ep_rsp);

        /* scrub most status bits, and flush any fifo state */
        if (ep->dev->pdev->device == 0x2280)
                tmp = (1 << FIFO_OVERFLOW)
                        | (1 << FIFO_UNDERFLOW);
        else
                tmp = 0;

        writel (tmp | (1 << TIMEOUT)
                | (1 << USB_STALL_SENT)
                | (1 << USB_IN_NAK_SENT)
                | (1 << USB_IN_ACK_RCVD)
                | (1 << USB_OUT_PING_NAK_SENT)
                | (1 << USB_OUT_ACK_SENT)
                | (1 << FIFO_FLUSH)
                | (1 << SHORT_PACKET_OUT_DONE_INTERRUPT)
                | (1 << SHORT_PACKET_TRANSFERRED_INTERRUPT)
                | (1 << DATA_PACKET_RECEIVED_INTERRUPT)
                | (1 << DATA_PACKET_TRANSMITTED_INTERRUPT)
                | (1 << DATA_OUT_PING_TOKEN_INTERRUPT)
                | (1 << DATA_IN_TOKEN_INTERRUPT)
                , &ep->regs->ep_stat);

        /* fifo size is handled separately */
}

static void nuke (struct net2280_ep *);

static int net2280_disable (struct usb_ep *_ep)
{
        struct net2280_ep       *ep;
        unsigned long           flags;

        ep = container_of (_ep, struct net2280_ep, ep);
        if (!_ep || !ep->desc || _ep->name == ep0name)
                return -EINVAL;

        spin_lock_irqsave (&ep->dev->lock, flags);
        nuke (ep);
        ep_reset (ep->dev->regs, ep);

        VDEBUG (ep->dev, "disabled %s %s\n",
                        ep->dma ? "dma" : "pio", _ep->name);

        /* synch memory views with the device */
        (void) readl (&ep->regs->ep_cfg);

        if (use_dma && !ep->dma && ep->num >= 1 && ep->num <= 4)
                ep->dma = &ep->dev->dma [ep->num - 1];

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

/*-------------------------------------------------------------------------*/

static struct usb_request *
net2280_alloc_request (struct usb_ep *_ep, gfp_t gfp_flags)
{
        struct net2280_ep       *ep;
        struct net2280_request  *req;

        if (!_ep)
                return NULL;
        ep = container_of (_ep, struct net2280_ep, ep);

        req = kzalloc(sizeof(*req), gfp_flags);
        if (!req)
                return NULL;

        req->req.dma = DMA_ADDR_INVALID;
        INIT_LIST_HEAD (&req->queue);

        /* this dma descriptor may be swapped with the previous dummy */
        if (ep->dma) {
                struct net2280_dma      *td;

                td = pci_pool_alloc (ep->dev->requests, gfp_flags,
                                &req->td_dma);
                if (!td) {
                        kfree (req);
                        return NULL;
                }
                td->dmacount = 0;       /* not VALID */
                td->dmaaddr = __constant_cpu_to_le32 (DMA_ADDR_INVALID);
                td->dmadesc = td->dmaaddr;
                req->td = td;
        }
        return &req->req;
}

static void
net2280_free_request (struct usb_ep *_ep, struct usb_request *_req)
{
        struct net2280_ep       *ep;
        struct net2280_request  *req;

        ep = container_of (_ep, struct net2280_ep, ep);
        if (!_ep || !_req)
                return;

        req = container_of (_req, struct net2280_request, req);
        WARN_ON (!list_empty (&req->queue));
        if (req->td)
                pci_pool_free (ep->dev->requests, req->td, req->td_dma);
        kfree (req);
}

/*-------------------------------------------------------------------------*/

/*
 * dma-coherent memory allocation (for dma-capable endpoints)
 *
 * NOTE: the dma_*_coherent() API calls suck.  Most implementations are
 * (a) page-oriented, so small buffers lose big; and (b) asymmetric with
 * respect to calls with irqs disabled:  alloc is safe, free is not.
 * We currently work around (b), but not (a).
 */

static void *
net2280_alloc_buffer (
        struct usb_ep           *_ep,
        unsigned                bytes,
        dma_addr_t              *dma,
        gfp_t                   gfp_flags
)
{
        void                    *retval;
        struct net2280_ep       *ep;

        ep = container_of (_ep, struct net2280_ep, ep);
        if (!_ep)
                return NULL;
        *dma = DMA_ADDR_INVALID;

        if (ep->dma)
                retval = dma_alloc_coherent(&ep->dev->pdev->dev,
                                bytes, dma, gfp_flags);
        else
                retval = kmalloc(bytes, gfp_flags);
        return retval;
}

static DEFINE_SPINLOCK(buflock);
static LIST_HEAD(buffers);

struct free_record {
        struct list_head        list;
        struct device           *dev;
        unsigned                bytes;
        dma_addr_t              dma;
};

static void do_free(unsigned long ignored)
{
        spin_lock_irq(&buflock);
        while (!list_empty(&buffers)) {
                struct free_record      *buf;

                buf = list_entry(buffers.next, struct free_record, list);
                list_del(&buf->list);
                spin_unlock_irq(&buflock);

                dma_free_coherent(buf->dev, buf->bytes, buf, buf->dma);

                spin_lock_irq(&buflock);
        }
        spin_unlock_irq(&buflock);
}

static DECLARE_TASKLET(deferred_free, do_free, 0);

static void
net2280_free_buffer (
        struct usb_ep *_ep,
        void *address,
        dma_addr_t dma,
        unsigned bytes
) {
        /* free memory into the right allocator */
        if (dma != DMA_ADDR_INVALID) {
                struct net2280_ep       *ep;
                struct free_record      *buf = address;
                unsigned long           flags;

                ep = container_of(_ep, struct net2280_ep, ep);
                if (!_ep)
                        return;

                ep = container_of (_ep, struct net2280_ep, ep);
                buf->dev = &ep->dev->pdev->dev;
                buf->bytes = bytes;
                buf->dma = dma;

                spin_lock_irqsave(&buflock, flags);
                list_add_tail(&buf->list, &buffers);
                tasklet_schedule(&deferred_free);
                spin_unlock_irqrestore(&buflock, flags);
        } else
                kfree (address);
}

/*-------------------------------------------------------------------------*/

/* load a packet into the fifo we use for usb IN transfers.
 * works for all endpoints.
 *
 * NOTE: pio with ep-a..ep-d could stuff multiple packets into the fifo
 * at a time, but this code is simpler because it knows it only writes
 * one packet.  ep-a..ep-d should use dma instead.
 */
static void
write_fifo (struct net2280_ep *ep, struct usb_request *req)
{
        struct net2280_ep_regs  __iomem *regs = ep->regs;
        u8                      *buf;
        u32                     tmp;
        unsigned                count, total;

        /* INVARIANT:  fifo is currently empty. (testable) */

        if (req) {
                buf = req->buf + req->actual;
                prefetch (buf);
                total = req->length - req->actual;
        } else {
                total = 0;
                buf = NULL;
        }

        /* write just one packet at a time */
        count = ep->ep.maxpacket;
        if (count > total)      /* min() cannot be used on a bitfield */
                count = total;

        VDEBUG (ep->dev, "write %s fifo (IN) %d bytes%s req %p\n",
                        ep->ep.name, count,
                        (count != ep->ep.maxpacket) ? " (short)" : "",
                        req);
        while (count >= 4) {
                /* NOTE be careful if you try to align these. fifo lines
                 * should normally be full (4 bytes) and successive partial
                 * lines are ok only in certain cases.
                 */
                tmp = get_unaligned ((u32 *)buf);
                cpu_to_le32s (&tmp);
                writel (tmp, &regs->ep_data);
                buf += 4;
                count -= 4;
        }

        /* last fifo entry is "short" unless we wrote a full packet.
         * also explicitly validate last word in (periodic) transfers
         * when maxpacket is not a multiple of 4 bytes.
         */
        if (count || total < ep->ep.maxpacket) {
                tmp = count ? get_unaligned ((u32 *)buf) : count;
                cpu_to_le32s (&tmp);
                set_fifo_bytecount (ep, count & 0x03);
                writel (tmp, &regs->ep_data);
        }

        /* pci writes may still be posted */
}

/* work around erratum 0106: PCI and USB race over the OUT fifo.
 * caller guarantees chiprev 0100, out endpoint is NAKing, and
 * there's no real data in the fifo.
 *
 * NOTE:  also used in cases where that erratum doesn't apply:
 * where the host wrote "too much" data to us.
 */
static void out_flush (struct net2280_ep *ep)
{
        u32     __iomem *statp;
        u32     tmp;

        ASSERT_OUT_NAKING (ep);

        statp = &ep->regs->ep_stat;
        writel (  (1 << DATA_OUT_PING_TOKEN_INTERRUPT)
                | (1 << DATA_PACKET_RECEIVED_INTERRUPT)
                , statp);
        writel ((1 << FIFO_FLUSH), statp);
        mb ();
        tmp = readl (statp);
        if (tmp & (1 << DATA_OUT_PING_TOKEN_INTERRUPT)
                        /* high speed did bulk NYET; fifo isn't filling */
                        && ep->dev->gadget.speed == USB_SPEED_FULL) {
                unsigned        usec;

                usec = 50;              /* 64 byte bulk/interrupt */
                handshake (statp, (1 << USB_OUT_PING_NAK_SENT),
                                (1 << USB_OUT_PING_NAK_SENT), usec);
                /* NAK done; now CLEAR_NAK_OUT_PACKETS is safe */
        }
}

/* unload packet(s) from the fifo we use for usb OUT transfers.
 * returns true iff the request completed, because of short packet
 * or the request buffer having filled with full packets.
 *
 * for ep-a..ep-d this will read multiple packets out when they
 * have been accepted.
 */
static int
read_fifo (struct net2280_ep *ep, struct net2280_request *req)
{
        struct net2280_ep_regs  __iomem *regs = ep->regs;
        u8                      *buf = req->req.buf + req->req.actual;
        unsigned                count, tmp, is_short;
        unsigned                cleanup = 0, prevent = 0;

        /* erratum 0106 ... packets coming in during fifo reads might
         * be incompletely rejected.  not all cases have workarounds.
         */
        if (ep->dev->chiprev == 0x0100
                        && ep->dev->gadget.speed == USB_SPEED_FULL) {
                udelay (1);
                tmp = readl (&ep->regs->ep_stat);
                if ((tmp & (1 << NAK_OUT_PACKETS)))
                        cleanup = 1;
                else if ((tmp & (1 << FIFO_FULL))) {
                        start_out_naking (ep);
                        prevent = 1;
                }
                /* else: hope we don't see the problem */
        }

        /* never overflow the rx buffer. the fifo reads packets until
         * it sees a short one; we might not be ready for them all.
         */
        prefetchw (buf);
        count = readl (&regs->ep_avail);
        if (unlikely (count == 0)) {
                udelay (1);
                tmp = readl (&ep->regs->ep_stat);
                count = readl (&regs->ep_avail);
                /* handled that data already? */
                if (count == 0 && (tmp & (1 << NAK_OUT_PACKETS)) == 0)
                        return 0;
        }

        tmp = req->req.length - req->req.actual;
        if (count > tmp) {
                /* as with DMA, data overflow gets flushed */
                if ((tmp % ep->ep.maxpacket) != 0) {
                        ERROR (ep->dev,
                                "%s out fifo %d bytes, expected %d\n",
                                ep->ep.name, count, tmp);
                        req->req.status = -EOVERFLOW;
                        cleanup = 1;
                        /* NAK_OUT_PACKETS will be set, so flushing is safe;
                         * the next read will start with the next packet
                         */
                } /* else it's a ZLP, no worries */
                count = tmp;
        }
        req->req.actual += count;

        is_short = (count == 0) || ((count % ep->ep.maxpacket) != 0);

        VDEBUG (ep->dev, "read %s fifo (OUT) %d bytes%s%s%s req %p %d/%d\n",
                        ep->ep.name, count, is_short ? " (short)" : "",
                        cleanup ? " flush" : "", prevent ? " nak" : "",
                        req, req->req.actual, req->req.length);

        while (count >= 4) {
                tmp = readl (&regs->ep_data);
                cpu_to_le32s (&tmp);
                put_unaligned (tmp, (u32 *)buf);
                buf += 4;
                count -= 4;
        }
        if (count) {
                tmp = readl (&regs->ep_data);
                /* LE conversion is implicit here: */
                do {
                        *buf++ = (u8) tmp;
                        tmp >>= 8;
                } while (--count);
        }
        if (cleanup)
                out_flush (ep);
        if (prevent) {
                writel ((1 << CLEAR_NAK_OUT_PACKETS), &ep->regs->ep_rsp);
                (void) readl (&ep->regs->ep_rsp);
        }

        return is_short || ((req->req.actual == req->req.length)
                                && !req->req.zero);
}

/* fill out dma descriptor to match a given request */
static void
fill_dma_desc (struct net2280_ep *ep, struct net2280_request *req, int valid)
{
        struct net2280_dma      *td = req->td;
        u32                     dmacount = req->req.length;

        /* don't let DMA continue after a short OUT packet,
         * so overruns can't affect the next transfer.
         * in case of overruns on max-size packets, we can't
         * stop the fifo from filling but we can flush it.
         */
        if (ep->is_in)
                dmacount |= (1 << DMA_DIRECTION);
        if ((!ep->is_in && (dmacount % ep->ep.maxpacket) != 0)
                        || ep->dev->pdev->device != 0x2280)
                dmacount |= (1 << END_OF_CHAIN);

        req->valid = valid;
        if (valid)
                dmacount |= (1 << VALID_BIT);
        if (likely(!req->req.no_interrupt || !use_dma_chaining))
                dmacount |= (1 << DMA_DONE_INTERRUPT_ENABLE);

        /* td->dmadesc = previously set by caller */
        td->dmaaddr = cpu_to_le32 (req->req.dma);

        /* 2280 may be polling VALID_BIT through ep->dma->dmadesc */
        wmb ();
        td->dmacount = cpu_to_le32p (&dmacount);
}

static const u32 dmactl_default =
                  (1 << DMA_SCATTER_GATHER_DONE_INTERRUPT)
                | (1 << DMA_CLEAR_COUNT_ENABLE)
                /* erratum 0116 workaround part 1 (use POLLING) */
                | (POLL_100_USEC << DESCRIPTOR_POLLING_RATE)
                | (1 << DMA_VALID_BIT_POLLING_ENABLE)
                | (1 << DMA_VALID_BIT_ENABLE)
                | (1 << DMA_SCATTER_GATHER_ENABLE)
                /* erratum 0116 workaround part 2 (no AUTOSTART) */
                | (1 << DMA_ENABLE);

static inline void spin_stop_dma (struct net2280_dma_regs __iomem *dma)
{
        handshake (&dma->dmactl, (1 << DMA_ENABLE), 0, 50);
}

static inline void stop_dma (struct net2280_dma_regs __iomem *dma)
{
        writel (readl (&dma->dmactl) & ~(1 << DMA_ENABLE), &dma->dmactl);
        spin_stop_dma (dma);
}

static void start_queue (struct net2280_ep *ep, u32 dmactl, u32 td_dma)
{
        struct net2280_dma_regs __iomem *dma = ep->dma;
        unsigned int tmp = (1 << VALID_BIT) | (ep->is_in << DMA_DIRECTION);

        if (ep->dev->pdev->device != 0x2280)
                tmp |= (1 << END_OF_CHAIN);

        writel (tmp, &dma->dmacount);
        writel (readl (&dma->dmastat), &dma->dmastat);

        writel (td_dma, &dma->dmadesc);
        writel (dmactl, &dma->dmactl);

        /* erratum 0116 workaround part 3:  pci arbiter away from net2280 */
        (void) readl (&ep->dev->pci->pcimstctl);

        writel ((1 << DMA_START), &dma->dmastat);

        if (!ep->is_in)
                stop_out_naking (ep);
}

static void start_dma (struct net2280_ep *ep, struct net2280_request *req)
{
        u32                     tmp;
        struct net2280_dma_regs __iomem *dma = ep->dma;

        /* FIXME can't use DMA for ZLPs */

        /* on this path we "know" there's no dma active (yet) */
        WARN_ON (readl (&dma->dmactl) & (1 << DMA_ENABLE));
        writel (0, &ep->dma->dmactl);

        /* previous OUT packet might have been short */
        if (!ep->is_in && ((tmp = readl (&ep->regs->ep_stat))
                                & (1 << NAK_OUT_PACKETS)) != 0) {
                writel ((1 << SHORT_PACKET_TRANSFERRED_INTERRUPT),
                        &ep->regs->ep_stat);

                tmp = readl (&ep->regs->ep_avail);
                if (tmp) {
                        writel (readl (&dma->dmastat), &dma->dmastat);

                        /* transfer all/some fifo data */
                        writel (req->req.dma, &dma->dmaaddr);
                        tmp = min (tmp, req->req.length);

                        /* dma irq, faking scatterlist status */
                        req->td->dmacount = cpu_to_le32 (req->req.length - tmp);
                        writel ((1 << DMA_DONE_INTERRUPT_ENABLE)
                                | tmp, &dma->dmacount);
                        req->td->dmadesc = 0;
                        req->valid = 1;

                        writel ((1 << DMA_ENABLE), &dma->dmactl);
                        writel ((1 << DMA_START), &dma->dmastat);
                        return;
                }
        }

        tmp = dmactl_default;

        /* force packet boundaries between dma requests, but prevent the
         * controller from automagically writing a last "short" packet
         * (zero length) unless the driver explicitly said to do that.
         */
        if (ep->is_in) {
                if (likely ((req->req.length % ep->ep.maxpacket) != 0
                                || req->req.zero)) {
                        tmp |= (1 << DMA_FIFO_VALIDATE);
                        ep->in_fifo_validate = 1;
                } else
                        ep->in_fifo_validate = 0;
        }

        /* init req->td, pointing to the current dummy */
        req->td->dmadesc = cpu_to_le32 (ep->td_dma);
        fill_dma_desc (ep, req, 1);

        if (!use_dma_chaining)
                req->td->dmacount |= __constant_cpu_to_le32 (1 << END_OF_CHAIN);

        start_queue (ep, tmp, req->td_dma);
}

static inline void
queue_dma (struct net2280_ep *ep, struct net2280_request *req, int valid)
{
        struct net2280_dma      *end;
        dma_addr_t              tmp;

        /* swap new dummy for old, link; fill and maybe activate */
        end = ep->dummy;
        ep->dummy = req->td;
        req->td = end;

        tmp = ep->td_dma;
        ep->td_dma = req->td_dma;
        req->td_dma = tmp;

        end->dmadesc = cpu_to_le32 (ep->td_dma);

        fill_dma_desc (ep, req, valid);
}

static void
done (struct net2280_ep *ep, struct net2280_request *req, int status)
{
        struct net2280          *dev;
        unsigned                stopped = ep->stopped;

        list_del_init (&req->queue);

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

        dev = ep->dev;
        if (req->mapped) {
                pci_unmap_single (dev->pdev, req->req.dma, req->req.length,
                        ep->is_in ? PCI_DMA_TODEVICE : PCI_DMA_FROMDEVICE);
                req->req.dma = DMA_ADDR_INVALID;
                req->mapped = 0;
        }

        if (status && status != -ESHUTDOWN)
                VDEBUG (dev, "complete %s req %p stat %d len %u/%u\n",
                        ep->ep.name, &req->req, status,
                        req->req.actual, req->req.length);

        /* don't modify queue heads during completion callback */
        ep->stopped = 1;
        spin_unlock (&dev->lock);
        req->req.complete (&ep->ep, &req->req);
        spin_lock (&dev->lock);
        ep->stopped = stopped;
}

/*-------------------------------------------------------------------------*/

static int
net2280_queue (struct usb_ep *_ep, struct usb_request *_req, gfp_t gfp_flags)
{
        struct net2280_request  *req;
        struct net2280_ep       *ep;
        struct net2280          *dev;
        unsigned long           flags;

        /* we always require a cpu-view buffer, so that we can
         * always use pio (as fallback or whatever).
         */
        req = container_of (_req, struct net2280_request, req);
        if (!_req || !_req->complete || !_req->buf
                        || !list_empty (&req->queue))
                return -EINVAL;
        if (_req->length > (~0 & DMA_BYTE_COUNT_MASK))
                return -EDOM;
        ep = container_of (_ep, struct net2280_ep, ep);
        if (!_ep || (!ep->desc && ep->num != 0))
                return -EINVAL;
        dev = ep->dev;
        if (!dev->driver || dev->gadget.speed == USB_SPEED_UNKNOWN)
                return -ESHUTDOWN;

        /* FIXME implement PIO fallback for ZLPs with DMA */
        if (ep->dma && _req->length == 0)
                return -EOPNOTSUPP;

        /* set up dma mapping in case the caller didn't */
        if (ep->dma && _req->dma == DMA_ADDR_INVALID) {
                _req->dma = pci_map_single (dev->pdev, _req->buf, _req->length,
                        ep->is_in ? PCI_DMA_TODEVICE : PCI_DMA_FROMDEVICE);
                req->mapped = 1;
        }

#if 0
        VDEBUG (dev, "%s queue req %p, len %d buf %p\n",
                        _ep->name, _req, _req->length, _req->buf);
#endif

        spin_lock_irqsave (&dev->lock, flags);

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

        /* kickstart this i/o queue? */
        if (list_empty (&ep->queue) && !ep->stopped) {
                /* use DMA if the endpoint supports it, else pio */
                if (ep->dma)
                        start_dma (ep, req);
                else {
                        /* maybe there's no control data, just status ack */
                        if (ep->num == 0 && _req->length == 0) {
                                allow_status (ep);
                                done (ep, req, 0);
                                VDEBUG (dev, "%s status ack\n", ep->ep.name);
                                goto done;
                        }

                        /* PIO ... stuff the fifo, or unblock it.  */
                        if (ep->is_in)
                                write_fifo (ep, _req);
                        else if (list_empty (&ep->queue)) {
                                u32     s;

                                /* OUT FIFO might have packet(s) buffered */
                                s = readl (&ep->regs->ep_stat);
                                if ((s & (1 << FIFO_EMPTY)) == 0) {
                                        /* note:  _req->short_not_ok is
                                         * ignored here since PIO _always_
                                         * stops queue advance here, and
                                         * _req->status doesn't change for
                                         * short reads (only _req->actual)
                                         */
                                        if (read_fifo (ep, req)) {
                                                done (ep, req, 0);
                                                if (ep->num == 0)
                                                        allow_status (ep);
                                                /* don't queue it */
                                                req = NULL;
                                        } else
                                                s = readl (&ep->regs->ep_stat);
                                }

                                /* don't NAK, let the fifo fill */
                                if (req && (s & (1 << NAK_OUT_PACKETS)))
                                        writel ((1 << CLEAR_NAK_OUT_PACKETS),
                                                        &ep->regs->ep_rsp);
                        }
                }

        } else if (ep->dma) {
                int     valid = 1;

                if (ep->is_in) {
                        int     expect;

                        /* preventing magic zlps is per-engine state, not
                         * per-transfer; irq logic must recover hiccups.
                         */
                        expect = likely (req->req.zero
                                || (req->req.length % ep->ep.maxpacket) != 0);
                        if (expect != ep->in_fifo_validate)
                                valid = 0;
                }
                queue_dma (ep, req, valid);

        } /* else the irq handler advances the queue. */

        if (req)
                list_add_tail (&req->queue, &ep->queue);
done:
        spin_unlock_irqrestore (&dev->lock, flags);

        /* pci writes may still be posted */
        return 0;
}

static inline void
dma_done (
        struct net2280_ep *ep,
        struct net2280_request *req,
        u32 dmacount,
        int status
)
{
        req->req.actual = req->req.length - (DMA_BYTE_COUNT_MASK & dmacount);
        done (ep, req, status);
}

static void restart_dma (struct net2280_ep *ep);

static void scan_dma_completions (struct net2280_ep *ep)
{
        /* only look at descriptors that were "naturally" retired,
         * so fifo and list head state won't matter
         */
        while (!list_empty (&ep->queue)) {
                struct net2280_request  *req;
                u32                     tmp;

                req = list_entry (ep->queue.next,
                                struct net2280_request, queue);
                if (!req->valid)
                        break;
                rmb ();
                tmp = le32_to_cpup (&req->td->dmacount);
                if ((tmp & (1 << VALID_BIT)) != 0)
                        break;

                /* SHORT_PACKET_TRANSFERRED_INTERRUPT handles "usb-short"
                 * cases where DMA must be aborted; this code handles
                 * all non-abort DMA completions.
                 */
                if (unlikely (req->td->dmadesc == 0)) {
                        /* paranoia */
                        tmp = readl (&ep->dma->dmacount);
                        if (tmp & DMA_BYTE_COUNT_MASK)
                                break;
                        /* single transfer mode */
                        dma_done (ep, req, tmp, 0);
                        break;
                } else if (!ep->is_in
                                && (req->req.length % ep->ep.maxpacket) != 0) {
                        tmp = readl (&ep->regs->ep_stat);

                        /* AVOID TROUBLE HERE by not issuing short reads from
                         * your gadget driver.  That helps avoids errata 0121,
                         * 0122, and 0124; not all cases trigger the warning.
                         */
                        if ((tmp & (1 << NAK_OUT_PACKETS)) == 0) {
                                WARN (ep->dev, "%s lost packet sync!\n",
                                                ep->ep.name);
                                req->req.status = -EOVERFLOW;
                        } else if ((tmp = readl (&ep->regs->ep_avail)) != 0) {
                                /* fifo gets flushed later */
                                ep->out_overflow = 1;
                                DEBUG (ep->dev, "%s dma, discard %d len %d\n",
                                                ep->ep.name, tmp,
                                                req->req.length);
                                req->req.status = -EOVERFLOW;
                        }
                }
                dma_done (ep, req, tmp, 0);
        }
}

static void restart_dma (struct net2280_ep *ep)
{
        struct net2280_request  *req;
        u32                     dmactl = dmactl_default;

        if (ep->stopped)
                return;
        req = list_entry (ep->queue.next, struct net2280_request, queue);

        if (!use_dma_chaining) {
                start_dma (ep, req);
                return;
        }

        /* the 2280 will be processing the queue unless queue hiccups after
         * the previous transfer:
         *  IN:   wanted automagic zlp, head doesn't (or vice versa)
         *        DMA_FIFO_VALIDATE doesn't init from dma descriptors.
         *  OUT:  was "usb-short", we must restart.
         */
        if (ep->is_in && !req->valid) {
                struct net2280_request  *entry, *prev = NULL;
                int                     reqmode, done = 0;

                DEBUG (ep->dev, "%s dma hiccup td %p\n", ep->ep.name, req->td);
                ep->in_fifo_validate = likely (req->req.zero
                        || (req->req.length % ep->ep.maxpacket) != 0);
                if (ep->in_fifo_validate)
                        dmactl |= (1 << DMA_FIFO_VALIDATE);
                list_for_each_entry (entry, &ep->queue, queue) {
                        __le32          dmacount;

                        if (entry == req)
                                continue;
                        dmacount = entry->td->dmacount;
                        if (!done) {
                                reqmode = likely (entry->req.zero
                                        || (entry->req.length
                                                % ep->ep.maxpacket) != 0);
                                if (reqmode == ep->in_fifo_validate) {
                                        entry->valid = 1;
                                        dmacount |= valid_bit;
                                        entry->td->dmacount = dmacount;
                                        prev = entry;
                                        continue;
                                } else {
                                        /* force a hiccup */
                                        prev->td->dmacount |= dma_done_ie;
                                        done = 1;
                                }
                        }

                        /* walk the rest of the queue so unlinks behave */
                        entry->valid = 0;
                        dmacount &= ~valid_bit;
                        entry->td->dmacount = dmacount;
                        prev = entry;
                }
        }

        writel (0, &ep->dma->dmactl);
        start_queue (ep, dmactl, req->td_dma);
}

static void abort_dma (struct net2280_ep *ep)
{
        /* abort the current transfer */
        if (likely (!list_empty (&ep->queue))) {
                /* FIXME work around errata 0121, 0122, 0124 */
                writel ((1 << DMA_ABORT), &ep->dma->dmastat);
                spin_stop_dma (ep->dma);
        } else
                stop_dma (ep->dma);
        scan_dma_completions (ep);
}

/* dequeue ALL requests */
static void nuke (struct net2280_ep *ep)
{
        struct net2280_request  *req;

        /* called with spinlock held */
        ep->stopped = 1;
        if (ep->dma)
                abort_dma (ep);
        while (!list_empty (&ep->queue)) {
                req = list_entry (ep->queue.next,
                                struct net2280_request,
                                queue);
                done (ep, req, -ESHUTDOWN);
        }
}

/* dequeue JUST ONE request */
static int net2280_dequeue (struct usb_ep *_ep, struct usb_request *_req)
{
        struct net2280_ep       *ep;
        struct net2280_request  *req;
        unsigned long           flags;
        u32                     dmactl;
        int                     stopped;

        ep = container_of (_ep, struct net2280_ep, ep);
        if (!_ep || (!ep->desc && ep->num != 0) || !_req)
                return -EINVAL;

        spin_lock_irqsave (&ep->dev->lock, flags);
        stopped = ep->stopped;

        /* quiesce dma while we patch the queue */
        dmactl = 0;
        ep->stopped = 1;
        if (ep->dma) {
                dmactl = readl (&ep->dma->dmactl);
                /* WARNING erratum 0127 may kick in ... */
                stop_dma (ep->dma);
                scan_dma_completions (ep);
        }

        /* make sure it's still queued on this endpoint */
        list_for_each_entry (req, &ep->queue, queue) {
                if (&req->req == _req)
                        break;
        }
        if (&req->req != _req) {
                spin_unlock_irqrestore (&ep->dev->lock, flags);
                return -EINVAL;
        }

        /* queue head may be partially complete. */
        if (ep->queue.next == &req->queue) {
                if (ep->dma) {
                        DEBUG (ep->dev, "unlink (%s) dma\n", _ep->name);
                        _req->status = -ECONNRESET;
                        abort_dma (ep);
                        if (likely (ep->queue.next == &req->queue)) {
                                // NOTE: misreports single-transfer mode
                                req->td->dmacount = 0;  /* invalidate */
                                dma_done (ep, req,
                                        readl (&ep->dma->dmacount),
                                        -ECONNRESET);
                        }
                } else {
                        DEBUG (ep->dev, "unlink (%s) pio\n", _ep->name);
                        done (ep, req, -ECONNRESET);
                }
                req = NULL;

        /* patch up hardware chaining data */
        } else if (ep->dma && use_dma_chaining) {
                if (req->queue.prev == ep->queue.next) {
                        writel (le32_to_cpu (req->td->dmadesc),
                                &ep->dma->dmadesc);
                        if (req->td->dmacount & dma_done_ie)
                                writel (readl (&ep->dma->dmacount)
                                                | le32_to_cpu(dma_done_ie),
                                        &ep->dma->dmacount);
                } else {
                        struct net2280_request  *prev;

                        prev = list_entry (req->queue.prev,
                                struct net2280_request, queue);
                        prev->td->dmadesc = req->td->dmadesc;
                        if (req->td->dmacount & dma_done_ie)
                                prev->td->dmacount |= dma_done_ie;
                }
        }

        if (req)
                done (ep, req, -ECONNRESET);
        ep->stopped = stopped;

        if (ep->dma) {
                /* turn off dma on inactive queues */
                if (list_empty (&ep->queue))
                        stop_dma (ep->dma);
                else if (!ep->stopped) {
                        /* resume current request, or start new one */
                        if (req)
                                writel (dmactl, &ep->dma->dmactl);
                        else
                                start_dma (ep, list_entry (ep->queue.next,
                                        struct net2280_request, queue));
                }
        }

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

/*-------------------------------------------------------------------------*/

static int net2280_fifo_status (struct usb_ep *_ep);

static int
net2280_set_halt (struct usb_ep *_ep, int value)
{
        struct net2280_ep       *ep;
        unsigned long           flags;
        int                     retval = 0;

        ep = container_of (_ep, struct net2280_ep, ep);
        if (!_ep || (!ep->desc && ep->num != 0))
                return -EINVAL;
        if (!ep->dev->driver || ep->dev->gadget.speed == USB_SPEED_UNKNOWN)
                return -ESHUTDOWN;
        if (ep->desc /* not ep0 */ && (ep->desc->bmAttributes & 0x03)
                                                == USB_ENDPOINT_XFER_ISOC)
                return -EINVAL;

        spin_lock_irqsave (&ep->dev->lock, flags);
        if (!list_empty (&ep->queue))
                retval = -EAGAIN;
        else if (ep->is_in && value && net2280_fifo_status (_ep) != 0)
                retval = -EAGAIN;
        else {
                VDEBUG (ep->dev, "%s %s halt\n", _ep->name,
                                value ? "set" : "clear");
                /* set/clear, then synch memory views with the device */
                if (value) {
                        if (ep->num == 0)
                                ep->dev->protocol_stall = 1;
                        else
                                set_halt (ep);
                } else
                        clear_halt (ep);
                (void) readl (&ep->regs->ep_rsp);
        }
        spin_unlock_irqrestore (&ep->dev->lock, flags);

        return retval;
}

static int
net2280_fifo_status (struct usb_ep *_ep)
{
        struct net2280_ep       *ep;
        u32                     avail;

        ep = container_of (_ep, struct net2280_ep, ep);
        if (!_ep || (!ep->desc && ep->num != 0))
                return -ENODEV;
        if (!ep->dev->driver || ep->dev->gadget.speed == USB_SPEED_UNKNOWN)
                return -ESHUTDOWN;

        avail = readl (&ep->regs->ep_avail) & ((1 << 12) - 1);
        if (avail > ep->fifo_size)
                return -EOVERFLOW;
        if (ep->is_in)
                avail = ep->fifo_size - avail;
        return avail;
}

static void
net2280_fifo_flush (struct usb_ep *_ep)
{
        struct net2280_ep       *ep;

        ep = container_of (_ep, struct net2280_ep, ep);
        if (!_ep || (!ep->desc && ep->num != 0))
                return;
        if (!ep->dev->driver || ep->dev->gadget.speed == USB_SPEED_UNKNOWN)
                return;

        writel ((1 << FIFO_FLUSH), &ep->regs->ep_stat);
        (void) readl (&ep->regs->ep_rsp);
}

static const struct usb_ep_ops net2280_ep_ops = {
        .enable         = net2280_enable,
        .disable        = net2280_disable,

        .alloc_request  = net2280_alloc_request,
        .free_request   = net2280_free_request,

        .alloc_buffer   = net2280_alloc_buffer,
        .free_buffer    = net2280_free_buffer,

        .queue          = net2280_queue,
        .dequeue        = net2280_dequeue,

        .set_halt       = net2280_set_halt,
        .fifo_status    = net2280_fifo_status,
        .fifo_flush     = net2280_fifo_flush,
};

/*-------------------------------------------------------------------------*/

static int net2280_get_frame (struct usb_gadget *_gadget)
{
        struct net2280          *dev;
        unsigned long           flags;
        u16                     retval;

        if (!_gadget)
                return -ENODEV;
        dev = container_of (_gadget, struct net2280, gadget);
        spin_lock_irqsave (&dev->lock, flags);
        retval = get_idx_reg (dev->regs, REG_FRAME) & 0x03ff;
        spin_unlock_irqrestore (&dev->lock, flags);
        return retval;
}

static int net2280_wakeup (struct usb_gadget *_gadget)
{
        struct net2280          *dev;
        u32                     tmp;
        unsigned long           flags;

        if (!_gadget)
                return 0;
        dev = container_of (_gadget, struct net2280, gadget);

        spin_lock_irqsave (&dev->lock, flags);
        tmp = readl (&dev->usb->usbctl);
        if (tmp & (1 << DEVICE_REMOTE_WAKEUP_ENABLE))
                writel (1 << GENERATE_RESUME, &dev->usb->usbstat);
        spin_unlock_irqrestore (&dev->lock, flags);

        /* pci writes may still be posted */
        return 0;
}

static int net2280_set_selfpowered (struct usb_gadget *_gadget, int value)
{
        struct net2280          *dev;
        u32                     tmp;
        unsigned long           flags;

        if (!_gadget)
                return 0;
        dev = container_of (_gadget, struct net2280, gadget);

        spin_lock_irqsave (&dev->lock, flags);
        tmp = readl (&dev->usb->usbctl);
        if (value)
                tmp |= (1 << SELF_POWERED_STATUS);
        else
                tmp &= ~(1 << SELF_POWERED_STATUS);
        writel (tmp, &dev->usb->usbctl);
        spin_unlock_irqrestore (&dev->lock, flags);

        return 0;
}

static int net2280_pullup(struct usb_gadget *_gadget, int is_on)
{
        struct net2280  *dev;
        u32             tmp;
        unsigned long   flags;

        if (!_gadget)
                return -ENODEV;
        dev = container_of (_gadget, struct net2280, gadget);

        spin_lock_irqsave (&dev->lock, flags);
        tmp = readl (&dev->usb->usbctl);
        dev->softconnect = (is_on != 0);
        if (is_on)
                tmp |= (1 << USB_DETECT_ENABLE);
        else
                tmp &= ~(1 << USB_DETECT_ENABLE);
        writel (tmp, &dev->usb->usbctl);
        spin_unlock_irqrestore (&dev->lock, flags);

        return 0;
}

static const struct usb_gadget_ops net2280_ops = {
        .get_frame      = net2280_get_frame,
        .wakeup         = net2280_wakeup,
        .set_selfpowered = net2280_set_selfpowered,
        .pullup         = net2280_pullup,
};

/*-------------------------------------------------------------------------*/

#ifdef  CONFIG_USB_GADGET_DEBUG_FILES

/* FIXME move these into procfs, and use seq_file.
 * Sysfs _still_ doesn't behave for arbitrarily sized files,
 * and also doesn't help products using this with 2.4 kernels.
 */

/* "function" sysfs attribute */
static ssize_t
show_function (struct device *_dev, struct device_attribute *attr, char *buf)
{
        struct net2280  *dev = dev_get_drvdata (_dev);

        if (!dev->driver
                        || !dev->driver->function
                        || strlen (dev->driver->function) > PAGE_SIZE)
                return 0;
        return scnprintf (buf, PAGE_SIZE, "%s\n", dev->driver->function);
}
static DEVICE_ATTR (function, S_IRUGO, show_function, NULL);

static ssize_t
show_registers (struct device *_dev, struct device_attribute *attr, char *buf)
{
        struct net2280          *dev;
        char                    *next;
        unsigned                size, t;
        unsigned long           flags;
        int                     i;
        u32                     t1, t2;
        const char              *s;

        dev = dev_get_drvdata (_dev);
        next = buf;
        size = PAGE_SIZE;
        spin_lock_irqsave (&dev->lock, flags);

        if (dev->driver)
                s = dev->driver->driver.name;
        else
                s = "(none)";

        /* Main Control Registers */
        t = scnprintf (next, size, "%s version " DRIVER_VERSION
                        ", chiprev %04x, dma %s\n\n"
                        "devinit %03x fifoctl %08x gadget '%s'\n"
                        "pci irqenb0 %02x irqenb1 %08x "
                        "irqstat0 %04x irqstat1 %08x\n",
                        driver_name, dev->chiprev,
                        use_dma
                                ? (use_dma_chaining ? "chaining" : "enabled")
                                : "disabled",
                        readl (&dev->regs->devinit),
                        readl (&dev->regs->fifoctl),
                        s,
                        readl (&dev->regs->pciirqenb0),
                        readl (&dev->regs->pciirqenb1),
                        readl (&dev->regs->irqstat0),
                        readl (&dev->regs->irqstat1));
        size -= t;
        next += t;

        /* USB Control Registers */
        t1 = readl (&dev->usb->usbctl);
        t2 = readl (&dev->usb->usbstat);
        if (t1 & (1 << VBUS_PIN)) {
                if (t2 & (1 << HIGH_SPEED))
                        s = "high speed";
                else if (dev->gadget.speed == USB_SPEED_UNKNOWN)
                        s = "powered";
                else
                        s = "full speed";
                /* full speed bit (6) not working?? */
        } else
                        s = "not attached";
        t = scnprintf (next, size,
                        "stdrsp %08x usbctl %08x usbstat %08x "
                                "addr 0x%02x (%s)\n",
                        readl (&dev->usb->stdrsp), t1, t2,
                        readl (&dev->usb->ouraddr), s);
        size -= t;
        next += t;

        /* PCI Master Control Registers */

        /* DMA Control Registers */

        /* Configurable EP Control Registers */
        for (i = 0; i < 7; i++) {
                struct net2280_ep       *ep;

                ep = &dev->ep [i];
                if (i && !ep->desc)
                        continue;

                t1 = readl (&ep->regs->ep_cfg);
                t2 = readl (&ep->regs->ep_rsp) & 0xff;
                t = scnprintf (next, size,
                                "\n%s\tcfg %05x rsp (%02x) %s%s%s%s%s%s%s%s"
                                        "irqenb %02x\n",
                                ep->ep.name, t1, t2,
                                (t2 & (1 << CLEAR_NAK_OUT_PACKETS))
                                        ? "NAK " : "",
                                (t2 & (1 << CLEAR_EP_HIDE_STATUS_PHASE))
                                        ? "hide " : "",
                                (t2 & (1 << CLEAR_EP_FORCE_CRC_ERROR))
                                        ? "CRC " : "",
                                (t2 & (1 << CLEAR_INTERRUPT_MODE))
                                        ? "interrupt " : "",
                                (t2 & (1<<CLEAR_CONTROL_STATUS_PHASE_HANDSHAKE))
                                        ? "status " : "",
                                (t2 & (1 << CLEAR_NAK_OUT_PACKETS_MODE))
                                        ? "NAKmode " : "",
                                (t2 & (1 << CLEAR_ENDPOINT_TOGGLE))
                                        ? "DATA1 " : "DATA0 ",
                                (t2 & (1 << CLEAR_ENDPOINT_HALT))
                                        ? "HALT " : "",
                                readl (&ep->regs->ep_irqenb));
                size -= t;
                next += t;

                t = scnprintf (next, size,
                                "\tstat %08x avail %04x "
                                "(ep%d%s-%s)%s\n",
                                readl (&ep->regs->ep_stat),
                                readl (&ep->regs->ep_avail),
                                t1 & 0x0f, DIR_STRING (t1),
                                type_string (t1 >> 8),
                                ep->stopped ? "*" : "");
                size -= t;
                next += t;

                if (!ep->dma)
                        continue;

                t = scnprintf (next, size,
                                "  dma\tctl %08x stat %08x count %08x\n"
                                "\taddr %08x desc %08x\n",
                                readl (&ep->dma->dmactl),
                                readl (&ep->dma->dmastat),
                                readl (&ep->dma->dmacount),
                                readl (&ep->dma->dmaaddr),
                                readl (&ep->dma->dmadesc));
                size -= t;
                next += t;

        }

        /* Indexed Registers */
                // none yet

        /* Statistics */
        t = scnprintf (next, size, "\nirqs:  ");
        size -= t;
        next += t;
        for (i = 0; i < 7; i++) {
                struct net2280_ep       *ep;

                ep = &dev->ep [i];
                if (i && !ep->irqs)
                        continue;
                t = scnprintf (next, size, " %s/%lu", ep->ep.name, ep->irqs);
                size -= t;
                next += t;

        }
        t = scnprintf (next, size, "\n");
        size -= t;
        next += t;

        spin_unlock_irqrestore (&dev->lock, flags);

        return PAGE_SIZE - size;
}
static DEVICE_ATTR (registers, S_IRUGO, show_registers, NULL);

static ssize_t
show_queues (struct device *_dev, struct device_attribute *attr, char *buf)
{
        struct net2280          *dev;
        char                    *next;
        unsigned                size;
        unsigned long           flags;
        int                     i;

        dev = dev_get_drvdata (_dev);
        next = buf;
        size = PAGE_SIZE;
        spin_lock_irqsave (&dev->lock, flags);

        for (i = 0; i < 7; i++) {
                struct net2280_ep               *ep = &dev->ep [i];
                struct net2280_request          *req;
                int                             t;

                if (i != 0) {
                        const struct usb_endpoint_descriptor    *d;

                        d = ep->desc;
                        if (!d)
                                continue;
                        t = d->bEndpointAddress;
                        t = scnprintf (next, size,
                                "\n%s (ep%d%s-%s) max %04x %s fifo %d\n",
                                ep->ep.name, t & USB_ENDPOINT_NUMBER_MASK,
                                (t & USB_DIR_IN) ? "in" : "out",
                                ({ char *val;
                                 switch (d->bmAttributes & 0x03) {
                                 case USB_ENDPOINT_XFER_BULK:
                                        val = "bulk"; break;
                                 case USB_ENDPOINT_XFER_INT:
                                        val = "intr"; break;
                                 default:
                                        val = "iso"; break;
                                 }; val; }),
                                le16_to_cpu (d->wMaxPacketSize) & 0x1fff,
                                ep->dma ? "dma" : "pio", ep->fifo_size
                                );
                } else /* ep0 should only have one transfer queued */
                        t = scnprintf (next, size, "ep0 max 64 pio %s\n",
                                        ep->is_in ? "in" : "out");
                if (t <= 0 || t > size)
                        goto done;
                size -= t;
                next += t;

                if (list_empty (&ep->queue)) {
                        t = scnprintf (next, size, "\t(nothing queued)\n");
                        if (t <= 0 || t > size)
                                goto done;
                        size -= t;
                        next += t;
                        continue;
                }
                list_for_each_entry (req, &ep->queue, queue) {
                        if (ep->dma && req->td_dma == readl (&ep->dma->dmadesc))
                                t = scnprintf (next, size,
                                        "\treq %p len %d/%d "
                                        "buf %p (dmacount %08x)\n",
                                        &req->req, req->req.actual,
                                        req->req.length, req->req.buf,
                                        readl (&ep->dma->dmacount));
                        else
                                t = scnprintf (next, size,
                                        "\treq %p len %d/%d buf %p\n",
                                        &req->req, req->req.actual,
                                        req->req.length, req->req.buf);
                        if (t <= 0 || t > size)
                                goto done;
                        size -= t;
                        next += t;

                        if (ep->dma) {
                                struct net2280_dma      *td;

                                td = req->td;
                                t = scnprintf (next, size, "\t    td %08x "
                                        " count %08x buf %08x desc %08x\n",
                                        (u32) req->td_dma,
                                        le32_to_cpu (td->dmacount),
                                        le32_to_cpu (td->dmaaddr),
                                        le32_to_cpu (td->dmadesc));
                                if (t <= 0 || t > size)
                                        goto done;
                                size -= t;
                                next += t;
                        }
                }
        }

done:
        spin_unlock_irqrestore (&dev->lock, flags);
        return PAGE_SIZE - size;
}
static DEVICE_ATTR (queues, S_IRUGO, show_queues, NULL);


#else

#define device_create_file(a,b) do {} while (0)
#define device_remove_file      device_create_file

#endif

/*-------------------------------------------------------------------------*/

/* another driver-specific mode might be a request type doing dma
 * to/from another device fifo instead of to/from memory.
 */

static void set_fifo_mode (struct net2280 *dev, int mode)
{
        /* keeping high bits preserves BAR2 */
        writel ((0xffff << PCI_BASE2_RANGE) | mode, &dev->regs->fifoctl);

        /* always ep-{a,b,e,f} ... maybe not ep-c or ep-d */
        INIT_LIST_HEAD (&dev->gadget.ep_list);
        list_add_tail (&dev->ep [1].ep.ep_list, &dev->gadget.ep_list);
        list_add_tail (&dev->ep [2].ep.ep_list, &dev->gadget.ep_list);
        switch (mode) {
        case 0:
                list_add_tail (&dev->ep [3].ep.ep_list, &dev->gadget.ep_list);
                list_add_tail (&dev->ep [4].ep.ep_list, &dev->gadget.ep_list);
                dev->ep [1].fifo_size = dev->ep [2].fifo_size = 1024;
                break;
        case 1:
                dev->ep [1].fifo_size = dev->ep [2].fifo_size = 2048;
                break;
        case 2:
                list_add_tail (&dev->ep [3].ep.ep_list, &dev->gadget.ep_list);
                dev->ep [1].fifo_size = 2048;
                dev->ep [2].fifo_size = 1024;
                break;
        }
        /* fifo sizes for ep0, ep-c, ep-d, ep-e, and ep-f never change */
        list_add_tail (&dev->ep [5].ep.ep_list, &dev->gadget.ep_list);
        list_add_tail (&dev->ep [6].ep.ep_list, &dev->gadget.ep_list);
}

/* just declare this in any driver that really need it */
extern int net2280_set_fifo_mode (struct usb_gadget *gadget, int mode);

/**
 * net2280_set_fifo_mode - change allocation of fifo buffers
 * @gadget: access to the net2280 device that will be updated
 * @mode: 0 for default, four 1kB buffers (ep-a through ep-d);
 *      1 for two 2kB buffers (ep-a and ep-b only);
 *      2 for one 2kB buffer (ep-a) and two 1kB ones (ep-b, ep-c).
 *
 * returns zero on success, else negative errno.  when this succeeds,
 * the contents of gadget->ep_list may have changed.
 *
 * you may only call this function when endpoints a-d are all disabled.
 * use it whenever extra hardware buffering can help performance, such
 * as before enabling "high bandwidth" interrupt endpoints that use
 * maxpacket bigger than 512 (when double buffering would otherwise
 * be unavailable).
 */
int net2280_set_fifo_mode (struct usb_gadget *gadget, int mode)
{
        int                     i;
        struct net2280          *dev;
        int                     status = 0;
        unsigned long           flags;

        if (!gadget)
                return -ENODEV;
        dev = container_of (gadget, struct net2280, gadget);

        spin_lock_irqsave (&dev->lock, flags);

        for (i = 1; i <= 4; i++)
                if (dev->ep [i].desc) {
                        status = -EINVAL;
                        break;
                }
        if (mode < 0 || mode > 2)
                status = -EINVAL;
        if (status == 0)
                set_fifo_mode (dev, mode);
        spin_unlock_irqrestore (&dev->lock, flags);

        if (status == 0) {
                if (mode == 1)
                        DEBUG (dev, "fifo:  ep-a 2K, ep-b 2K\n");
                else if (mode == 2)
                        DEBUG (dev, "fifo:  ep-a 2K, ep-b 1K, ep-c 1K\n");
                /* else all are 1K */
        }
        return status;
}
EXPORT_SYMBOL (net2280_set_fifo_mode);

/*-------------------------------------------------------------------------*/

/* keeping it simple:
 * - one bus driver, initted first;
 * - one function driver, initted second
 *
 * most of the work to support multiple net2280 controllers would
 * be to associate this gadget driver (yes?) with all of them, or
 * perhaps to bind specific drivers to specific devices.
 */

static struct net2280   *the_controller;

static void usb_reset (struct net2280 *dev)
{
        u32     tmp;

        dev->gadget.speed = USB_SPEED_UNKNOWN;
        (void) readl (&dev->usb->usbctl);

        net2280_led_init (dev);

        /* disable automatic responses, and irqs */
        writel (0, &dev->usb->stdrsp);
        writel (0, &dev->regs->pciirqenb0);
        writel (0, &dev->regs->pciirqenb1);

        /* clear old dma and irq state */
        for (tmp = 0; tmp < 4; tmp++) {
                struct net2280_ep       *ep = &dev->ep [tmp + 1];

                if (ep->dma)
                        abort_dma (ep);
        }
        writel (~0, &dev->regs->irqstat0),
        writel (~(1 << SUSPEND_REQUEST_INTERRUPT), &dev->regs->irqstat1),

        /* reset, and enable pci */
        tmp = readl (&dev->regs->devinit)
                | (1 << PCI_ENABLE)
                | (1 << FIFO_SOFT_RESET)
                | (1 << USB_SOFT_RESET)
                | (1 << M8051_RESET);
        writel (tmp, &dev->regs->devinit);

        /* standard fifo and endpoint allocations */
        set_fifo_mode (dev, (fifo_mode <= 2) ? fifo_mode : 0);
}

static void usb_reinit (struct net2280 *dev)
{
        u32     tmp;
        int     init_dma;

        /* use_dma changes are ignored till next device re-init */
        init_dma = use_dma;

        /* basic endpoint init */
        for (tmp = 0; tmp < 7; tmp++) {
                struct net2280_ep       *ep = &dev->ep [tmp];

                ep->ep.name = ep_name [tmp];
                ep->dev = dev;
                ep->num = tmp;

                if (tmp > 0 && tmp <= 4) {
                        ep->fifo_size = 1024;
                        if (init_dma)
                                ep->dma = &dev->dma [tmp - 1];
                } else
                        ep->fifo_size = 64;
                ep->regs = &dev->epregs [tmp];
                ep_reset (dev->regs, ep);
        }
        dev->ep [0].ep.maxpacket = 64;
        dev->ep [5].ep.maxpacket = 64;
        dev->ep [6].ep.maxpacket = 64;

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

        /* we want to prevent lowlevel/insecure access from the USB host,
         * but erratum 0119 means this enable bit is ignored
         */
        for (tmp = 0; tmp < 5; tmp++)
                writel (EP_DONTUSE, &dev->dep [tmp].dep_cfg);
}

static void ep0_start (struct net2280 *dev)
{
        writel (  (1 << CLEAR_EP_HIDE_STATUS_PHASE)
                | (1 << CLEAR_NAK_OUT_PACKETS)
                | (1 << CLEAR_CONTROL_STATUS_PHASE_HANDSHAKE)
                , &dev->epregs [0].ep_rsp);

        /*
         * hardware optionally handles a bunch of standard requests
         * that the API hides from drivers anyway.  have it do so.
         * endpoint status/features are handled in software, to
         * help pass tests for some dubious behavior.
         */
        writel (  (1 << SET_TEST_MODE)
                | (1 << SET_ADDRESS)
                | (1 << DEVICE_SET_CLEAR_DEVICE_REMOTE_WAKEUP)
                | (1 << GET_DEVICE_STATUS)
                | (1 << GET_INTERFACE_STATUS)
                , &dev->usb->stdrsp);
        writel (  (1 << USB_ROOT_PORT_WAKEUP_ENABLE)
                | (1 << SELF_POWERED_USB_DEVICE)
                | (1 << REMOTE_WAKEUP_SUPPORT)
                | (dev->softconnect << USB_DETECT_ENABLE)
                | (1 << SELF_POWERED_STATUS)
                , &dev->usb->usbctl);

        /* enable irqs so we can see ep0 and general operation  */
        writel (  (1 << SETUP_PACKET_INTERRUPT_ENABLE)
                | (1 << ENDPOINT_0_INTERRUPT_ENABLE)
                , &dev->regs->pciirqenb0);
        writel (  (1 << PCI_INTERRUPT_ENABLE)
                | (1 << PCI_MASTER_ABORT_RECEIVED_INTERRUPT_ENABLE)
                | (1 << PCI_TARGET_ABORT_RECEIVED_INTERRUPT_ENABLE)
                | (1 << PCI_RETRY_ABORT_INTERRUPT_ENABLE)
                | (1 << VBUS_INTERRUPT_ENABLE)
                | (1 << ROOT_PORT_RESET_INTERRUPT_ENABLE)
                | (1 << SUSPEND_REQUEST_CHANGE_INTERRUPT_ENABLE)
                , &dev->regs->pciirqenb1);

        /* don't leave any writes posted */
        (void) readl (&dev->usb->usbctl);
}

/* when a driver is successfully registered, it will receive
 * control requests including set_configuration(), which enables
 * non-control requests.  then usb traffic follows until a
 * disconnect is reported.  then a host may connect again, or
 * the driver might get unbound.
 */
int usb_gadget_register_driver (struct usb_gadget_driver *driver)
{
        struct net2280          *dev = the_controller;
        int                     retval;
        unsigned                i;

        /* insist on high speed support from the driver, since
         * (dev->usb->xcvrdiag & FORCE_FULL_SPEED_MODE)
         * "must not be used in normal operation"
         */
        if (!driver
                        || driver->speed != USB_SPEED_HIGH
                        || !driver->bind
                        || !driver->unbind
                        || !driver->setup)
                return -EINVAL;
        if (!dev)
                return -ENODEV;
        if (dev->driver)
                return -EBUSY;

        for (i = 0; i < 7; i++)
                dev->ep [i].irqs = 0;

        /* hook up the driver ... */
        dev->softconnect = 1;
        driver->driver.bus = NULL;
        dev->driver = driver;
        dev->gadget.dev.driver = &driver->driver;
        retval = driver->bind (&dev->gadget);
        if (retval) {
                DEBUG (dev, "bind to driver %s --> %d\n",
                                driver->driver.name, retval);
                dev->driver = NULL;
                dev->gadget.dev.driver = NULL;
                return retval;
        }

        device_create_file (&dev->pdev->dev, &dev_attr_function);
        device_create_file (&dev->pdev->dev, &dev_attr_queues);

        /* ... then enable host detection and ep0; and we're ready
         * for set_configuration as well as eventual disconnect.
         */
        net2280_led_active (dev, 1);
        ep0_start (dev);

        DEBUG (dev, "%s ready, usbctl %08x stdrsp %08x\n",
                        driver->driver.name,
                        readl (&dev->usb->usbctl),
                        readl (&dev->usb->stdrsp));

        /* pci writes may still be posted */
        return 0;
}
EXPORT_SYMBOL (usb_gadget_register_driver);

static void
stop_activity (struct net2280 *dev, struct usb_gadget_driver *driver)
{
        int                     i;

        /* don't disconnect if it's not connected */
        if (dev->gadget.speed == USB_SPEED_UNKNOWN)
                driver = NULL;

        /* stop hardware; prevent new request submissions;
         * and kill any outstanding requests.
         */
        usb_reset (dev);
        for (i = 0; i < 7; i++)
                nuke (&dev->ep [i]);

        /* report disconnect; the driver is already quiesced */
        if (driver) {
                spin_unlock (&dev->lock);
                driver->disconnect (&dev->gadget);
                spin_lock (&dev->lock);
        }

        usb_reinit (dev);
}

int usb_gadget_unregister_driver (struct usb_gadget_driver *driver)
{
        struct net2280  *dev = the_controller;
        unsigned long   flags;

        if (!dev)
                return -ENODEV;
        if (!driver || driver != dev->driver)
                return -EINVAL;

        spin_lock_irqsave (&dev->lock, flags);
        stop_activity (dev, driver);
        spin_unlock_irqrestore (&dev->lock, flags);

        net2280_pullup (&dev->gadget, 0);

        driver->unbind (&dev->gadget);
        dev->gadget.dev.driver = NULL;
        dev->driver = NULL;

        net2280_led_active (dev, 0);
        device_remove_file (&dev->pdev->dev, &dev_attr_function);
        device_remove_file (&dev->pdev->dev, &dev_attr_queues);

        DEBUG (dev, "unregistered driver '%s'\n", driver->driver.name);
        return 0;
}
EXPORT_SYMBOL (usb_gadget_unregister_driver);


/*-------------------------------------------------------------------------*/

/* handle ep0, ep-e, ep-f with 64 byte packets: packet per irq.
 * also works for dma-capable endpoints, in pio mode or just
 * to manually advance the queue after short OUT transfers.
 */
static void handle_ep_small (struct net2280_ep *ep)
{
        struct net2280_request  *req;
        u32                     t;
        /* 0 error, 1 mid-data, 2 done */
        int                     mode = 1;

        if (!list_empty (&ep->queue))
                req = list_entry (ep->queue.next,
                        struct net2280_request, queue);
        else
                req = NULL;

        /* ack all, and handle what we care about */
        t = readl (&ep->regs->ep_stat);
        ep->irqs++;
#if 0
        VDEBUG (ep->dev, "%s ack ep_stat %08x, req %p\n",
                        ep->ep.name, t, req ? &req->req : 0);
#endif
        if (!ep->is_in || ep->dev->pdev->device == 0x2280)
                writel (t & ~(1 << NAK_OUT_PACKETS), &ep->regs->ep_stat);
        else
                /* Added for 2282 */
                writel (t, &ep->regs->ep_stat);

        /* for ep0, monitor token irqs to catch data stage length errors
         * and to synchronize on status.
         *
         * also, to defer reporting of protocol stalls ... here's where
         * data or status first appears, handling stalls here should never
         * cause trouble on the host side..
         *
         * control requests could be slightly faster without token synch for
         * status, but status can jam up that way.
         */
        if (unlikely (ep->num == 0)) {
                if (ep->is_in) {
                        /* status; stop NAKing */
                        if (t & (1 << DATA_OUT_PING_TOKEN_INTERRUPT)) {
                                if (ep->dev->protocol_stall) {
                                        ep->stopped = 1;
                                        set_halt (ep);
                                }
                                if (!req)
                                        allow_status (ep);
                                mode = 2;
                        /* reply to extra IN data tokens with a zlp */
                        } else if (t & (1 << DATA_IN_TOKEN_INTERRUPT)) {
                                if (ep->dev->protocol_stall) {
                                        ep->stopped = 1;
                                        set_halt (ep);
                                        mode = 2;
                                } else if (!req && !ep->stopped)
                                        write_fifo (ep, NULL);
                        }
                } else {
                        /* status; stop NAKing */
                        if (t & (1 << DATA_IN_TOKEN_INTERRUPT)) {
                                if (ep->dev->protocol_stall) {
                                        ep->stopped = 1;
                                        set_halt (ep);
                                }
                                mode = 2;
                        /* an extra OUT token is an error */
                        } else if (((t & (1 << DATA_OUT_PING_TOKEN_INTERRUPT))
                                        && req
                                        && req->req.actual == req->req.length)
                                        || !req) {
                                ep->dev->protocol_stall = 1;
                                set_halt (ep);
                                ep->stopped = 1;
                                if (req)
                                        done (ep, req, -EOVERFLOW);
                                req = NULL;
                        }
                }
        }

        if (unlikely (!req))
                return;

        /* manual DMA queue advance after short OUT */
        if (likely (ep->dma != 0)) {
                if (t & (1 << SHORT_PACKET_TRANSFERRED_INTERRUPT)) {
                        u32     count;
                        int     stopped = ep->stopped;

                        /* TRANSFERRED works around OUT_DONE erratum 0112.
                         * we expect (N <= maxpacket) bytes; host wrote M.
                         * iff (M < N) we won't ever see a DMA interrupt.
                         */
                        ep->stopped = 1;
                        for (count = 0; ; t = readl (&ep->regs->ep_stat)) {

                                /* any preceding dma transfers must finish.
                                 * dma handles (M >= N), may empty the queue
                                 */
                                scan_dma_completions (ep);
                                if (unlikely (list_empty (&ep->queue)
                                                || ep->out_overflow)) {
                                        req = NULL;
                                        break;
                                }
                                req = list_entry (ep->queue.next,
                                        struct net2280_request, queue);

                                /* here either (M < N), a "real" short rx;
                                 * or (M == N) and the queue didn't empty
                                 */
                                if (likely (t & (1 << FIFO_EMPTY))) {
                                        count = readl (&ep->dma->dmacount);
                                        count &= DMA_BYTE_COUNT_MASK;
                                        if (readl (&ep->dma->dmadesc)
                                                        != req->td_dma)
                                                req = NULL;
                                        break;
                                }
                                udelay(1);
                        }

                        /* stop DMA, leave ep NAKing */
                        writel ((1 << DMA_ABORT), &ep->dma->dmastat);
                        spin_stop_dma (ep->dma);

                        if (likely (req)) {
                                req->td->dmacount = 0;
                                t = readl (&ep->regs->ep_avail);
                                dma_done (ep, req, count,
                                        (ep->out_overflow || t)
                                                ? -EOVERFLOW : 0);
                        }

                        /* also flush to prevent erratum 0106 trouble */
                        if (unlikely (ep->out_overflow
                                        || (ep->dev->chiprev == 0x0100
                                                && ep->dev->gadget.speed
                                                        == USB_SPEED_FULL))) {
                                out_flush (ep);
                                ep->out_overflow = 0;
                        }

                        /* (re)start dma if needed, stop NAKing */
                        ep->stopped = stopped;
                        if (!list_empty (&ep->queue))
                                restart_dma (ep);
                } else
                        DEBUG (ep->dev, "%s dma ep_stat %08x ??\n",
                                        ep->ep.name, t);
                return;

        /* data packet(s) received (in the fifo, OUT) */
        } else if (t & (1 << DATA_PACKET_RECEIVED_INTERRUPT)) {
                if (read_fifo (ep, req) && ep->num != 0)
                        mode = 2;

        /* data packet(s) transmitted (IN) */
        } else if (t & (1 << DATA_PACKET_TRANSMITTED_INTERRUPT)) {
                unsigned        len;

                len = req->req.length - req->req.actual;
                if (len > ep->ep.maxpacket)
                        len = ep->ep.maxpacket;
                req->req.actual += len;

                /* if we wrote it all, we're usually done */
                if (req->req.actual == req->req.length) {
                        if (ep->num == 0) {
                                /* send zlps until the status stage */
                        } else if (!req->req.zero || len != ep->ep.maxpacket)
                                mode = 2;
                }

        /* there was nothing to do ...  */
        } else if (mode == 1)
                return;

        /* done */
        if (mode == 2) {
                /* stream endpoints often resubmit/unlink in completion */
                done (ep, req, 0);

                /* maybe advance queue to next request */
                if (ep->num == 0) {
                        /* NOTE:  net2280 could let gadget driver start the
                         * status stage later. since not all controllers let
                         * them control that, the api doesn't (yet) allow it.
                         */
                        if (!ep->stopped)
                                allow_status (ep);
                        req = NULL;
                } else {
                        if (!list_empty (&ep->queue) && !ep->stopped)
                                req = list_entry (ep->queue.next,
                                        struct net2280_request, queue);
                        else
                                req = NULL;
                        if (req && !ep->is_in)
                                stop_out_naking (ep);
                }
        }

        /* is there a buffer for the next packet?
         * for best streaming performance, make sure there is one.
         */
        if (req && !ep->stopped) {

                /* load IN fifo with next packet (may be zlp) */
                if (t & (1 << DATA_PACKET_TRANSMITTED_INTERRUPT))
                        write_fifo (ep, &req->req);
        }
}

static struct net2280_ep *
get_ep_by_addr (struct net2280 *dev, u16 wIndex)
{
        struct net2280_ep       *ep;

        if ((wIndex & USB_ENDPOINT_NUMBER_MASK) == 0)
                return &dev->ep [0];
        list_for_each_entry (ep, &dev->gadget.ep_list, ep.ep_list) {
                u8      bEndpointAddress;

                if (!ep->desc)
                        continue;
                bEndpointAddress = ep->desc->bEndpointAddress;
                if ((wIndex ^ bEndpointAddress) & USB_DIR_IN)
                        continue;
                if ((wIndex & 0x0f) == (bEndpointAddress & 0x0f))
                        return ep;
        }
        return NULL;
}

static void handle_stat0_irqs (struct net2280 *dev, u32 stat)
{
        struct net2280_ep       *ep;
        u32                     num, scratch;

        /* most of these don't need individual acks */
        stat &= ~(1 << INTA_ASSERTED);
        if (!stat)
                return;
        // DEBUG (dev, "irqstat0 %04x\n", stat);

        /* starting a control request? */
        if (unlikely (stat & (1 << SETUP_PACKET_INTERRUPT))) {
                union {
                        u32                     raw [2];
                        struct usb_ctrlrequest  r;
                } u;
                int                             tmp;
                struct net2280_request          *req;

                if (dev->gadget.speed == USB_SPEED_UNKNOWN) {
                        if (readl (&dev->usb->usbstat) & (1 << HIGH_SPEED))
                                dev->gadget.speed = USB_SPEED_HIGH;
                        else
                                dev->gadget.speed = USB_SPEED_FULL;
                        net2280_led_speed (dev, dev->gadget.speed);
                        DEBUG (dev, "%s speed\n",
                                (dev->gadget.speed == USB_SPEED_HIGH)
                                        ? "high" : "full");
                }

                ep = &dev->ep [0];
                ep->irqs++;

                /* make sure any leftover request state is cleared */
                stat &= ~(1 << ENDPOINT_0_INTERRUPT);
                while (!list_empty (&ep->queue)) {
                        req = list_entry (ep->queue.next,
                                        struct net2280_request, queue);
                        done (ep, req, (req->req.actual == req->req.length)
                                                ? 0 : -EPROTO);
                }
                ep->stopped = 0;
                dev->protocol_stall = 0;

                if (ep->dev->pdev->device == 0x2280)
                        tmp = (1 << FIFO_OVERFLOW)
                                | (1 << FIFO_UNDERFLOW);
                else
                        tmp = 0;

                writel (tmp | (1 << TIMEOUT)
                        | (1 << USB_STALL_SENT)
                        | (1 << USB_IN_NAK_SENT)
                        | (1 << USB_IN_ACK_RCVD)
                        | (1 << USB_OUT_PING_NAK_SENT)
                        | (1 << USB_OUT_ACK_SENT)
                        | (1 << SHORT_PACKET_OUT_DONE_INTERRUPT)
                        | (1 << SHORT_PACKET_TRANSFERRED_INTERRUPT)
                        | (1 << DATA_PACKET_RECEIVED_INTERRUPT)
                        | (1 << DATA_PACKET_TRANSMITTED_INTERRUPT)
                        | (1 << DATA_OUT_PING_TOKEN_INTERRUPT)
                        | (1 << DATA_IN_TOKEN_INTERRUPT)
                        , &ep->regs->ep_stat);
                u.raw [0] = readl (&dev->usb->setup0123);
                u.raw [1] = readl (&dev->usb->setup4567);

                cpu_to_le32s (&u.raw [0]);
                cpu_to_le32s (&u.raw [1]);

                tmp = 0;

#define w_value         le16_to_cpup (&u.r.wValue)
#define w_index         le16_to_cpup (&u.r.wIndex)
#define w_length        le16_to_cpup (&u.r.wLength)

                /* ack the irq */
                writel (1 << SETUP_PACKET_INTERRUPT, &dev->regs->irqstat0);
                stat ^= (1 << SETUP_PACKET_INTERRUPT);

                /* watch control traffic at the token level, and force
                 * synchronization before letting the status stage happen.
                 * FIXME ignore tokens we'll NAK, until driver responds.
                 * that'll mean a lot less irqs for some drivers.
                 */
                ep->is_in = (u.r.bRequestType & USB_DIR_IN) != 0;
                if (ep->is_in) {
                        scratch = (1 << DATA_PACKET_TRANSMITTED_INTERRUPT)
                                | (1 << DATA_OUT_PING_TOKEN_INTERRUPT)
                                | (1 << DATA_IN_TOKEN_INTERRUPT);
                        stop_out_naking (ep);
                } else
                        scratch = (1 << DATA_PACKET_RECEIVED_INTERRUPT)
                                | (1 << DATA_OUT_PING_TOKEN_INTERRUPT)
                                | (1 << DATA_IN_TOKEN_INTERRUPT);
                writel (scratch, &dev->epregs [0].ep_irqenb);

                /* we made the hardware handle most lowlevel requests;
                 * everything else goes uplevel to the gadget code.
                 */
                switch (u.r.bRequest) {
                case USB_REQ_GET_STATUS: {
                        struct net2280_ep       *e;
                        __le32                  status;

                        /* hw handles device and interface status */
                        if (u.r.bRequestType != (USB_DIR_IN|USB_RECIP_ENDPOINT))
                                goto delegate;
                        if ((e = get_ep_by_addr (dev, w_index)) == 0
                                        || w_length > 2)
                                goto do_stall;

                        if (readl (&e->regs->ep_rsp)
                                        & (1 << SET_ENDPOINT_HALT))
                                status = __constant_cpu_to_le32 (1);
                        else
                                status = __constant_cpu_to_le32 (0);

                        /* don't bother with a request object! */
                        writel (0, &dev->epregs [0].ep_irqenb);
                        set_fifo_bytecount (ep, w_length);
                        writel ((__force u32)status, &dev->epregs [0].ep_data);
                        allow_status (ep);
                        VDEBUG (dev, "%s stat %02x\n", ep->ep.name, status);
                        goto next_endpoints;
                        }
                        break;
                case USB_REQ_CLEAR_FEATURE: {
                        struct net2280_ep       *e;

                        /* hw handles device features */
                        if (u.r.bRequestType != USB_RECIP_ENDPOINT)
                                goto delegate;
                        if (w_value != USB_ENDPOINT_HALT
                                        || w_length != 0)
                                goto do_stall;
                        if ((e = get_ep_by_addr (dev, w_index)) == 0)
                                goto do_stall;
                        clear_halt (e);
                        allow_status (ep);
                        VDEBUG (dev, "%s clear halt\n", ep->ep.name);
                        goto next_endpoints;
                        }
                        break;
                case USB_REQ_SET_FEATURE: {
                        struct net2280_ep       *e;

                        /* hw handles device features */
                        if (u.r.bRequestType != USB_RECIP_ENDPOINT)
                                goto delegate;
                        if (w_value != USB_ENDPOINT_HALT
                                        || w_length != 0)
                                goto do_stall;
                        if ((e = get_ep_by_addr (dev, w_index)) == 0)
                                goto do_stall;
                        set_halt (e);
                        allow_status (ep);
                        VDEBUG (dev, "%s set halt\n", ep->ep.name);
                        goto next_endpoints;
                        }
                        break;
                default:
delegate:
                        VDEBUG (dev, "setup %02x.%02x v%04x i%04x l%04x"
                                "ep_cfg %08x\n",
                                u.r.bRequestType, u.r.bRequest,
                                w_value, w_index, w_length,
                                readl (&ep->regs->ep_cfg));
                        spin_unlock (&dev->lock);
                        tmp = dev->driver->setup (&dev->gadget, &u.r);
                        spin_lock (&dev->lock);
                }

                /* stall ep0 on error */
                if (tmp < 0) {
do_stall:
                        VDEBUG (dev, "req %02x.%02x protocol STALL; stat %d\n",
                                        u.r.bRequestType, u.r.bRequest, tmp);
                        dev->protocol_stall = 1;
                }

                /* some in/out token irq should follow; maybe stall then.
                 * driver must queue a request (even zlp) or halt ep0
                 * before the host times out.
                 */
        }

#undef  w_value
#undef  w_index
#undef  w_length

next_endpoints:
        /* endpoint data irq ? */
        scratch = stat & 0x7f;
        stat &= ~0x7f;
        for (num = 0; scratch; num++) {
                u32             t;

                /* do this endpoint's FIFO and queue need tending? */
                t = 1 << num;
                if ((scratch & t) == 0)
                        continue;
                scratch ^= t;

                ep = &dev->ep [num];
                handle_ep_small (ep);
        }

        if (stat)
                DEBUG (dev, "unhandled irqstat0 %08x\n", stat);
}

#define DMA_INTERRUPTS ( \
                  (1 << DMA_D_INTERRUPT) \
                | (1 << DMA_C_INTERRUPT) \
                | (1 << DMA_B_INTERRUPT) \
                | (1 << DMA_A_INTERRUPT))
#define PCI_ERROR_INTERRUPTS ( \
                  (1 << PCI_MASTER_ABORT_RECEIVED_INTERRUPT) \
                | (1 << PCI_TARGET_ABORT_RECEIVED_INTERRUPT) \
                | (1 << PCI_RETRY_ABORT_INTERRUPT))

static void handle_stat1_irqs (struct net2280 *dev, u32 stat)
{
        struct net2280_ep       *ep;
        u32                     tmp, num, mask, scratch;

        /* after disconnect there's nothing else to do! */
        tmp = (1 << VBUS_INTERRUPT) | (1 << ROOT_PORT_RESET_INTERRUPT);
        mask = (1 << HIGH_SPEED) | (1 << FULL_SPEED);

        /* VBUS disconnect is indicated by VBUS_PIN and VBUS_INTERRUPT set.
         * Root Port Reset is indicated by ROOT_PORT_RESET_INTERRRUPT set and
         * both HIGH_SPEED and FULL_SPEED clear (as ROOT_PORT_RESET_INTERRUPT
         * only indicates a change in the reset state).
         */
        if (stat & tmp) {
                writel (tmp, &dev->regs->irqstat1);
                if ((((stat & (1 << ROOT_PORT_RESET_INTERRUPT))
                                        && ((readl (&dev->usb->usbstat) & mask)
                                                        == 0))
                                || ((readl (&dev->usb->usbctl)
                                        & (1 << VBUS_PIN)) == 0)
                            ) && ( dev->gadget.speed != USB_SPEED_UNKNOWN)) {
                        DEBUG (dev, "disconnect %s\n",
                                        dev->driver->driver.name);
                        stop_activity (dev, dev->driver);
                        ep0_start (dev);
                        return;
                }
                stat &= ~tmp;

                /* vBUS can bounce ... one of many reasons to ignore the
                 * notion of hotplug events on bus connect/disconnect!
                 */
                if (!stat)
                        return;
        }

        /* NOTE: chip stays in PCI D0 state for now, but it could
         * enter D1 to save more power
         */
        tmp = (1 << SUSPEND_REQUEST_CHANGE_INTERRUPT);
        if (stat & tmp) {
                writel (tmp, &dev->regs->irqstat1);
                if (stat & (1 << SUSPEND_REQUEST_INTERRUPT)) {
                        if (dev->driver->suspend)
                                dev->driver->suspend (&dev->gadget);
                        if (!enable_suspend)
                                stat &= ~(1 << SUSPEND_REQUEST_INTERRUPT);
                } else {
                        if (dev->driver->resume)
                                dev->driver->resume (&dev->gadget);
                        /* at high speed, note erratum 0133 */
                }
                stat &= ~tmp;
        }

        /* clear any other status/irqs */
        if (stat)
                writel (stat, &dev->regs->irqstat1);

        /* some status we can just ignore */
        if (dev->pdev->device == 0x2280)
                stat &= ~((1 << CONTROL_STATUS_INTERRUPT)
                          | (1 << SUSPEND_REQUEST_INTERRUPT)
                          | (1 << RESUME_INTERRUPT)
                          | (1 << SOF_INTERRUPT));
        else
                stat &= ~((1 << CONTROL_STATUS_INTERRUPT)
                          | (1 << RESUME_INTERRUPT)
                          | (1 << SOF_DOWN_INTERRUPT)
                          | (1 << SOF_INTERRUPT));

        if (!stat)
                return;
        // DEBUG (dev, "irqstat1 %08x\n", stat);

        /* DMA status, for ep-{a,b,c,d} */
        scratch = stat & DMA_INTERRUPTS;
        stat &= ~DMA_INTERRUPTS;
        scratch >>= 9;
        for (num = 0; scratch; num++) {
                struct net2280_dma_regs __iomem *dma;

                tmp = 1 << num;
                if ((tmp & scratch) == 0)
                        continue;
                scratch ^= tmp;

                ep = &dev->ep [num + 1];
                dma = ep->dma;

                if (!dma)
                        continue;

                /* clear ep's dma status */
                tmp = readl (&dma->dmastat);
                writel (tmp, &dma->dmastat);

                /* chaining should stop on abort, short OUT from fifo,
                 * or (stat0 codepath) short OUT transfer.
                 */
                if (!use_dma_chaining) {
                        if ((tmp & (1 << DMA_TRANSACTION_DONE_INTERRUPT))
                                        == 0) {
                                DEBUG (ep->dev, "%s no xact done? %08x\n",
                                        ep->ep.name, tmp);
                                continue;
                        }
                        stop_dma (ep->dma);
                }

                /* OUT transfers terminate when the data from the
                 * host is in our memory.  Process whatever's done.
                 * On this path, we know transfer's last packet wasn't
                 * less than req->length. NAK_OUT_PACKETS may be set,
                 * or the FIFO may already be holding new packets.
                 *
                 * IN transfers can linger in the FIFO for a very
                 * long time ... we ignore that for now, accounting
                 * precisely (like PIO does) needs per-packet irqs
                 */
                scan_dma_completions (ep);

                /* disable dma on inactive queues; else maybe restart */
                if (list_empty (&ep->queue)) {
                        if (use_dma_chaining)
                                stop_dma (ep->dma);
                } else {
                        tmp = readl (&dma->dmactl);
                        if (!use_dma_chaining
                                        || (tmp & (1 << DMA_ENABLE)) == 0)
                                restart_dma (ep);
                        else if (ep->is_in && use_dma_chaining) {
                                struct net2280_request  *req;
                                __le32                  dmacount;

                                /* the descriptor at the head of the chain
                                 * may still have VALID_BIT clear; that's
                                 * used to trigger changing DMA_FIFO_VALIDATE
                                 * (affects automagic zlp writes).
                                 */
                                req = list_entry (ep->queue.next,
                                                struct net2280_request, queue);
                                dmacount = req->td->dmacount;
                                dmacount &= __constant_cpu_to_le32 (
                                                (1 << VALID_BIT)
                                                | DMA_BYTE_COUNT_MASK);
                                if (dmacount && (dmacount & valid_bit) == 0)
                                        restart_dma (ep);
                        }
                }
                ep->irqs++;
        }

        /* NOTE:  there are other PCI errors we might usefully notice.
         * if they appear very often, here's where to try recovering.
         */
        if (stat & PCI_ERROR_INTERRUPTS) {
                ERROR (dev, "pci dma error; stat %08x\n", stat);
                stat &= ~PCI_ERROR_INTERRUPTS;
                /* these are fatal errors, but "maybe" they won't
                 * happen again ...
                 */
                stop_activity (dev, dev->driver);
                ep0_start (dev);
                stat = 0;
        }

        if (stat)
                DEBUG (dev, "unhandled irqstat1 %08x\n", stat);
}

static irqreturn_t net2280_irq (int irq, void *_dev, struct pt_regs * r)
{
        struct net2280          *dev = _dev;

        /* shared interrupt, not ours */
        if (!(readl(&dev->regs->irqstat0) & (1 << INTA_ASSERTED)))
                return IRQ_NONE;

        spin_lock (&dev->lock);

        /* handle disconnect, dma, and more */
        handle_stat1_irqs (dev, readl (&dev->regs->irqstat1));

        /* control requests and PIO */
        handle_stat0_irqs (dev, readl (&dev->regs->irqstat0));

        spin_unlock (&dev->lock);

        return IRQ_HANDLED;
}

/*-------------------------------------------------------------------------*/

static void gadget_release (struct device *_dev)
{
        struct net2280  *dev = dev_get_drvdata (_dev);

        kfree (dev);
}

/* tear down the binding between this driver and the pci device */

static void net2280_remove (struct pci_dev *pdev)
{
        struct net2280          *dev = pci_get_drvdata (pdev);

        /* start with the driver above us */
        if (dev->driver) {
                /* should have been done already by driver model core */
                WARN (dev, "pci remove, driver '%s' is still registered\n",
                                dev->driver->driver.name);
                usb_gadget_unregister_driver (dev->driver);
        }

        /* then clean up the resources we allocated during probe() */
        net2280_led_shutdown (dev);
        if (dev->requests) {
                int             i;
                for (i = 1; i < 5; i++) {
                        if (!dev->ep [i].dummy)
                                continue;
                        pci_pool_free (dev->requests, dev->ep [i].dummy,
                                        dev->ep [i].td_dma);
                }
                pci_pool_destroy (dev->requests);
        }
        if (dev->got_irq)
                free_irq (pdev->irq, dev);
        if (dev->regs)
                iounmap (dev->regs);
        if (dev->region)
                release_mem_region (pci_resource_start (pdev, 0),
                                pci_resource_len (pdev, 0));
        if (dev->enabled)
                pci_disable_device (pdev);
        device_unregister (&dev->gadget.dev);
        device_remove_file (&pdev->dev, &dev_attr_registers);
        pci_set_drvdata (pdev, NULL);

        INFO (dev, "unbind\n");

        the_controller = NULL;
}

/* wrap this driver around the specified device, but
 * don't respond over USB until a gadget driver binds to us.
 */

static int net2280_probe (struct pci_dev *pdev, const struct pci_device_id *id)
{
        struct net2280          *dev;
        unsigned long           resource, len;
        void                    __iomem *base = NULL;
        int                     retval, i;

        /* if you want to support more than one controller in a system,
         * usb_gadget_driver_{register,unregister}() must change.
         */
        if (the_controller) {
                dev_warn (&pdev->dev, "ignoring\n");
                return -EBUSY;
        }

        /* alloc, and start init */
        dev = kzalloc (sizeof *dev, SLAB_KERNEL);
        if (dev == NULL){
                retval = -ENOMEM;
                goto done;
        }

        pci_set_drvdata (pdev, dev);
        spin_lock_init (&dev->lock);
        dev->pdev = pdev;
        dev->gadget.ops = &net2280_ops;
        dev->gadget.is_dualspeed = 1;

        /* the "gadget" abstracts/virtualizes the controller */
        strcpy (dev->gadget.dev.bus_id, "gadget");
        dev->gadget.dev.parent = &pdev->dev;
        dev->gadget.dev.dma_mask = pdev->dev.dma_mask;
        dev->gadget.dev.release = gadget_release;
        dev->gadget.name = driver_name;

        /* now all the pci goodies ... */
        if (pci_enable_device (pdev) < 0) {
                retval = -ENODEV;
                goto done;
        }
        dev->enabled = 1;

        /* BAR 0 holds all the registers
         * BAR 1 is 8051 memory; unused here (note erratum 0103)
         * BAR 2 is fifo memory; unused here
         */
        resource = pci_resource_start (pdev, 0);
        len = pci_resource_len (pdev, 0);
        if (!request_mem_region (resource, len, driver_name)) {
                DEBUG (dev, "controller already in use\n");
                retval = -EBUSY;
                goto done;
        }
        dev->region = 1;

        /* FIXME provide firmware download interface to put
         * 8051 code into the chip, e.g. to turn on PCI PM.
         */

        base = ioremap_nocache (resource, len);
        if (base == NULL) {
                DEBUG (dev, "can't map memory\n");
                retval = -EFAULT;
                goto done;
        }
        dev->regs = (struct net2280_regs __iomem *) base;
        dev->usb = (struct net2280_usb_regs __iomem *) (base + 0x0080);
        dev->pci = (struct net2280_pci_regs __iomem *) (base + 0x0100);
        dev->dma = (struct net2280_dma_regs __iomem *) (base + 0x0180);
        dev->dep = (struct net2280_dep_regs __iomem *) (base + 0x0200);
        dev->epregs = (struct net2280_ep_regs __iomem *) (base + 0x0300);

        /* put into initial config, link up all endpoints */
        writel (0, &dev->usb->usbctl);
        usb_reset (dev);
        usb_reinit (dev);

        /* irq setup after old hardware is cleaned up */
        if (!pdev->irq) {
                ERROR (dev, "No IRQ.  Check PCI setup!\n");
                retval = -ENODEV;
                goto done;
        }

        if (request_irq (pdev->irq, net2280_irq, IRQF_SHARED, driver_name, dev)
                        != 0) {
                ERROR (dev, "request interrupt %d failed\n", pdev->irq);
                retval = -EBUSY;
                goto done;
        }
        dev->got_irq = 1;

        /* DMA setup */
        /* NOTE:  we know only the 32 LSBs of dma addresses may be nonzero */
        dev->requests = pci_pool_create ("requests", pdev,
                sizeof (struct net2280_dma),
                0 /* no alignment requirements */,
                0 /* or page-crossing issues */);
        if (!dev->requests) {
                DEBUG (dev, "can't get request pool\n");
                retval = -ENOMEM;
                goto done;
        }
        for (i = 1; i < 5; i++) {
                struct net2280_dma      *td;

                td = pci_pool_alloc (dev->requests, GFP_KERNEL,
                                &dev->ep [i].td_dma);
                if (!td) {
                        DEBUG (dev, "can't get dummy %d\n", i);
                        retval = -ENOMEM;
                        goto done;
                }
                td->dmacount = 0;       /* not VALID */
                td->dmaaddr = __constant_cpu_to_le32 (DMA_ADDR_INVALID);
                td->dmadesc = td->dmaaddr;
                dev->ep [i].dummy = td;
        }

        /* enable lower-overhead pci memory bursts during DMA */
        writel ( (1 << DMA_MEMORY_WRITE_AND_INVALIDATE_ENABLE)
                        // 256 write retries may not be enough...
                        // | (1 << PCI_RETRY_ABORT_ENABLE)
                        | (1 << DMA_READ_MULTIPLE_ENABLE)
                        | (1 << DMA_READ_LINE_ENABLE)
                        , &dev->pci->pcimstctl);
        /* erratum 0115 shouldn't appear: Linux inits PCI_LATENCY_TIMER */
        pci_set_master (pdev);
        pci_set_mwi (pdev);

        /* ... also flushes any posted pci writes */
        dev->chiprev = get_idx_reg (dev->regs, REG_CHIPREV) & 0xffff;

        /* done */
        INFO (dev, "%s\n", driver_desc);
        INFO (dev, "irq %d, pci mem %p, chip rev %04x\n",
                        pdev->irq, base, dev->chiprev);
        INFO (dev, "version: " DRIVER_VERSION "; dma %s\n",
                        use_dma
                                ? (use_dma_chaining ? "chaining" : "enabled")
                                : "disabled");
        the_controller = dev;

        device_register (&dev->gadget.dev);
        device_create_file (&pdev->dev, &dev_attr_registers);

        return 0;

done:
        if (dev)
                net2280_remove (pdev);
        return retval;
}

/* make sure the board is quiescent; otherwise it will continue
 * generating IRQs across the upcoming reboot.
 */

static void net2280_shutdown (struct pci_dev *pdev)
{
        struct net2280          *dev = pci_get_drvdata (pdev);

        /* disable IRQs */
        writel (0, &dev->regs->pciirqenb0);
        writel (0, &dev->regs->pciirqenb1);

        /* disable the pullup so the host will think we're gone */
        writel (0, &dev->usb->usbctl);
}


/*-------------------------------------------------------------------------*/

static const struct pci_device_id pci_ids [] = { {
        .class =        ((PCI_CLASS_SERIAL_USB << 8) | 0xfe),
        .class_mask =   ~0,
        .vendor =       0x17cc,
        .device =       0x2280,
        .subvendor =    PCI_ANY_ID,
        .subdevice =    PCI_ANY_ID,
}, {
        .class =        ((PCI_CLASS_SERIAL_USB << 8) | 0xfe),
        .class_mask =   ~0,
        .vendor =       0x17cc,
        .device =       0x2282,
        .subvendor =    PCI_ANY_ID,
        .subdevice =    PCI_ANY_ID,

}, { /* end: all zeroes */ }
};
MODULE_DEVICE_TABLE (pci, pci_ids);

/* pci driver glue; this is a "new style" PCI driver module */
static struct pci_driver net2280_pci_driver = {
        .name =         (char *) driver_name,
        .id_table =     pci_ids,

        .probe =        net2280_probe,
        .remove =       net2280_remove,
        .shutdown =     net2280_shutdown,

        /* FIXME add power management support */
};

MODULE_DESCRIPTION (DRIVER_DESC);
MODULE_AUTHOR ("David Brownell");
MODULE_LICENSE ("GPL");

static int __init init (void)
{
        if (!use_dma)
                use_dma_chaining = 0;
        return pci_register_driver (&net2280_pci_driver);
}
module_init (init);

static void __exit cleanup (void)
{
        pci_unregister_driver (&net2280_pci_driver);
}
module_exit (cleanup);