#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/scatterlist.h>
#include <linux/mutex.h>
#include <linux/timer.h>
#include <linux/usb.h>

#define SIMPLE_IO_TIMEOUT       10000   /* in milliseconds */

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

static int override_alt = -1;
module_param_named(alt, override_alt, int, 0644);
MODULE_PARM_DESC(alt, ">= 0 to override altsetting selection");
static void complicated_callback(struct urb *urb);

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

/* FIXME make these public somewhere; usbdevfs.h? */

/* Parameter for usbtest driver. */
struct usbtest_param_32 {
        /* inputs */
        __u32           test_num;       /* 0..(TEST_CASES-1) */
        __u32           iterations;
        __u32           length;
        __u32           vary;
        __u32           sglen;

        /* outputs */
        __s32           duration_sec;
        __s32           duration_usec;
};

/*
 * Compat parameter to the usbtest driver.
 * This supports older user space binaries compiled with 64 bit compiler.
 */
struct usbtest_param_64 {
        /* inputs */
        __u32           test_num;       /* 0..(TEST_CASES-1) */
        __u32           iterations;
        __u32           length;
        __u32           vary;
        __u32           sglen;

        /* outputs */
        __s64           duration_sec;
        __s64           duration_usec;
};

/* IOCTL interface to the driver. */
#define USBTEST_REQUEST_32    _IOWR('U', 100, struct usbtest_param_32)
/* COMPAT IOCTL interface to the driver. */
#define USBTEST_REQUEST_64    _IOWR('U', 100, struct usbtest_param_64)

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

#define GENERIC         /* let probe() bind using module params */

/* Some devices that can be used for testing will have "real" drivers.
 * Entries for those need to be enabled here by hand, after disabling
 * that "real" driver.
 */
//#define       IBOT2           /* grab iBOT2 webcams */
//#define       KEYSPAN_19Qi    /* grab un-renumerated serial adapter */

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

struct usbtest_info {
        const char              *name;
        u8                      ep_in;          /* bulk/intr source */
        u8                      ep_out;         /* bulk/intr sink */
        unsigned                autoconf:1;
        unsigned                ctrl_out:1;
        unsigned                iso:1;          /* try iso in/out */
        unsigned                intr:1;         /* try interrupt in/out */
        int                     alt;
};

/* this is accessed only through usbfs ioctl calls.
 * one ioctl to issue a test ... one lock per device.
 * tests create other threads if they need them.
 * urbs and buffers are allocated dynamically,
 * and data generated deterministically.
 */
struct usbtest_dev {
        struct usb_interface    *intf;
        struct usbtest_info     *info;
        int                     in_pipe;
        int                     out_pipe;
        int                     in_iso_pipe;
        int                     out_iso_pipe;
        int                     in_int_pipe;
        int                     out_int_pipe;
        struct usb_endpoint_descriptor  *iso_in, *iso_out;
        struct usb_endpoint_descriptor  *int_in, *int_out;
        struct mutex            lock;

#define TBUF_SIZE       256
        u8                      *buf;
};

static struct usb_device *testdev_to_usbdev(struct usbtest_dev *test)
{
        return interface_to_usbdev(test->intf);
}

/* set up all urbs so they can be used with either bulk or interrupt */
#define INTERRUPT_RATE          1       /* msec/transfer */

#define ERROR(tdev, fmt, args...) \
        dev_err(&(tdev)->intf->dev , fmt , ## args)
#define WARNING(tdev, fmt, args...) \
        dev_warn(&(tdev)->intf->dev , fmt , ## args)

#define GUARD_BYTE      0xA5
#define MAX_SGLEN       128

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

static int
get_endpoints(struct usbtest_dev *dev, struct usb_interface *intf)
{
        int                             tmp;
        struct usb_host_interface       *alt;
        struct usb_host_endpoint        *in, *out;
        struct usb_host_endpoint        *iso_in, *iso_out;
        struct usb_host_endpoint        *int_in, *int_out;
        struct usb_device               *udev;

        for (tmp = 0; tmp < intf->num_altsetting; tmp++) {
                unsigned        ep;

                in = out = NULL;
                iso_in = iso_out = NULL;
                int_in = int_out = NULL;
                alt = intf->altsetting + tmp;

                if (override_alt >= 0 &&
                                override_alt != alt->desc.bAlternateSetting)
                        continue;

                /* take the first altsetting with in-bulk + out-bulk;
                 * ignore other endpoints and altsettings.
                 */
                for (ep = 0; ep < alt->desc.bNumEndpoints; ep++) {
                        struct usb_host_endpoint        *e;

                        e = alt->endpoint + ep;
                        switch (usb_endpoint_type(&e->desc)) {
                        case USB_ENDPOINT_XFER_BULK:
                                break;
                        case USB_ENDPOINT_XFER_INT:
                                if (dev->info->intr)
                                        goto try_intr;
                        case USB_ENDPOINT_XFER_ISOC:
                                if (dev->info->iso)
                                        goto try_iso;
                                /* FALLTHROUGH */
                        default:
                                continue;
                        }
                        if (usb_endpoint_dir_in(&e->desc)) {
                                if (!in)
                                        in = e;
                        } else {
                                if (!out)
                                        out = e;
                        }
                        continue;
try_intr:
                        if (usb_endpoint_dir_in(&e->desc)) {
                                if (!int_in)
                                        int_in = e;
                        } else {
                                if (!int_out)
                                        int_out = e;
                        }
                        continue;
try_iso:
                        if (usb_endpoint_dir_in(&e->desc)) {
                                if (!iso_in)
                                        iso_in = e;
                        } else {
                                if (!iso_out)
                                        iso_out = e;
                        }
                }
                if ((in && out)  ||  iso_in || iso_out || int_in || int_out)
                        goto found;
        }
        return -EINVAL;

found:
        udev = testdev_to_usbdev(dev);
        dev->info->alt = alt->desc.bAlternateSetting;
        if (alt->desc.bAlternateSetting != 0) {
                tmp = usb_set_interface(udev,
                                alt->desc.bInterfaceNumber,
                                alt->desc.bAlternateSetting);
                if (tmp < 0)
                        return tmp;
        }

        if (in) {
                dev->in_pipe = usb_rcvbulkpipe(udev,
                        in->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
                dev->out_pipe = usb_sndbulkpipe(udev,
                        out->desc.bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
        }
        if (iso_in) {
                dev->iso_in = &iso_in->desc;
                dev->in_iso_pipe = usb_rcvisocpipe(udev,
                                iso_in->desc.bEndpointAddress
                                        & USB_ENDPOINT_NUMBER_MASK);
        }

        if (iso_out) {
                dev->iso_out = &iso_out->desc;
                dev->out_iso_pipe = usb_sndisocpipe(udev,
                                iso_out->desc.bEndpointAddress
                                        & USB_ENDPOINT_NUMBER_MASK);
        }

        if (int_in) {
                dev->int_in = &int_in->desc;
                dev->in_int_pipe = usb_rcvintpipe(udev,
                                int_in->desc.bEndpointAddress
                                        & USB_ENDPOINT_NUMBER_MASK);
        }

        if (int_out) {
                dev->int_out = &int_out->desc;
                dev->out_int_pipe = usb_sndintpipe(udev,
                                int_out->desc.bEndpointAddress
                                        & USB_ENDPOINT_NUMBER_MASK);
        }
        return 0;
}

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

/* Support for testing basic non-queued I/O streams.
 *
 * These just package urbs as requests that can be easily canceled.
 * Each urb's data buffer is dynamically allocated; callers can fill
 * them with non-zero test data (or test for it) when appropriate.
 */

static void simple_callback(struct urb *urb)
{
        complete(urb->context);
}

static struct urb *usbtest_alloc_urb(
        struct usb_device       *udev,
        int                     pipe,
        unsigned long           bytes,
        unsigned                transfer_flags,
        unsigned                offset,
        u8                      bInterval,
        usb_complete_t          complete_fn)
{
        struct urb              *urb;

        urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!urb)
                return urb;

        if (bInterval)
                usb_fill_int_urb(urb, udev, pipe, NULL, bytes, complete_fn,
                                NULL, bInterval);
        else
                usb_fill_bulk_urb(urb, udev, pipe, NULL, bytes, complete_fn,
                                NULL);

        urb->interval = (udev->speed == USB_SPEED_HIGH)
                        ? (INTERRUPT_RATE << 3)
                        : INTERRUPT_RATE;
        urb->transfer_flags = transfer_flags;
        if (usb_pipein(pipe))
                urb->transfer_flags |= URB_SHORT_NOT_OK;

        if (urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
                urb->transfer_buffer = usb_alloc_coherent(udev, bytes + offset,
                        GFP_KERNEL, &urb->transfer_dma);
        else
                urb->transfer_buffer = kmalloc(bytes + offset, GFP_KERNEL);

        if (!urb->transfer_buffer) {
                usb_free_urb(urb);
                return NULL;
        }

        /* To test unaligned transfers add an offset and fill the
                unused memory with a guard value */
        if (offset) {
                memset(urb->transfer_buffer, GUARD_BYTE, offset);
                urb->transfer_buffer += offset;
                if (urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
                        urb->transfer_dma += offset;
        }

        /* For inbound transfers use guard byte so that test fails if
                data not correctly copied */
        memset(urb->transfer_buffer,
                        usb_pipein(urb->pipe) ? GUARD_BYTE : 0,
                        bytes);
        return urb;
}

static struct urb *simple_alloc_urb(
        struct usb_device       *udev,
        int                     pipe,
        unsigned long           bytes,
        u8                      bInterval)
{
        return usbtest_alloc_urb(udev, pipe, bytes, URB_NO_TRANSFER_DMA_MAP, 0,
                        bInterval, simple_callback);
}

static struct urb *complicated_alloc_urb(
        struct usb_device       *udev,
        int                     pipe,
        unsigned long           bytes,
        u8                      bInterval)
{
        return usbtest_alloc_urb(udev, pipe, bytes, URB_NO_TRANSFER_DMA_MAP, 0,
                        bInterval, complicated_callback);
}

static unsigned pattern;
static unsigned mod_pattern;
module_param_named(pattern, mod_pattern, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(mod_pattern, "i/o pattern (0 == zeroes)");

static unsigned get_maxpacket(struct usb_device *udev, int pipe)
{
        struct usb_host_endpoint        *ep;

        ep = usb_pipe_endpoint(udev, pipe);
        return le16_to_cpup(&ep->desc.wMaxPacketSize);
}

static void simple_fill_buf(struct urb *urb)
{
        unsigned        i;
        u8              *buf = urb->transfer_buffer;
        unsigned        len = urb->transfer_buffer_length;
        unsigned        maxpacket;

        switch (pattern) {
        default:
                /* FALLTHROUGH */
        case 0:
                memset(buf, 0, len);
                break;
        case 1:                 /* mod63 */
                maxpacket = get_maxpacket(urb->dev, urb->pipe);
                for (i = 0; i < len; i++)
                        *buf++ = (u8) ((i % maxpacket) % 63);
                break;
        }
}

static inline unsigned long buffer_offset(void *buf)
{
        return (unsigned long)buf & (ARCH_KMALLOC_MINALIGN - 1);
}

static int check_guard_bytes(struct usbtest_dev *tdev, struct urb *urb)
{
        u8 *buf = urb->transfer_buffer;
        u8 *guard = buf - buffer_offset(buf);
        unsigned i;

        for (i = 0; guard < buf; i++, guard++) {
                if (*guard != GUARD_BYTE) {
                        ERROR(tdev, "guard byte[%d] %d (not %d)\n",
                                i, *guard, GUARD_BYTE);
                        return -EINVAL;
                }
        }
        return 0;
}

static int simple_check_buf(struct usbtest_dev *tdev, struct urb *urb)
{
        unsigned        i;
        u8              expected;
        u8              *buf = urb->transfer_buffer;
        unsigned        len = urb->actual_length;
        unsigned        maxpacket = get_maxpacket(urb->dev, urb->pipe);

        int ret = check_guard_bytes(tdev, urb);
        if (ret)
                return ret;

        for (i = 0; i < len; i++, buf++) {
                switch (pattern) {
                /* all-zeroes has no synchronization issues */
                case 0:
                        expected = 0;
                        break;
                /* mod63 stays in sync with short-terminated transfers,
                 * or otherwise when host and gadget agree on how large
                 * each usb transfer request should be.  resync is done
                 * with set_interface or set_config.
                 */
                case 1:                 /* mod63 */
                        expected = (i % maxpacket) % 63;
                        break;
                /* always fail unsupported patterns */
                default:
                        expected = !*buf;
                        break;
                }
                if (*buf == expected)
                        continue;
                ERROR(tdev, "buf[%d] = %d (not %d)\n", i, *buf, expected);
                return -EINVAL;
        }
        return 0;
}

static void simple_free_urb(struct urb *urb)
{
        unsigned long offset = buffer_offset(urb->transfer_buffer);

        if (urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
                usb_free_coherent(
                        urb->dev,
                        urb->transfer_buffer_length + offset,
                        urb->transfer_buffer - offset,
                        urb->transfer_dma - offset);
        else
                kfree(urb->transfer_buffer - offset);
        usb_free_urb(urb);
}

static int simple_io(
        struct usbtest_dev      *tdev,
        struct urb              *urb,
        int                     iterations,
        int                     vary,
        int                     expected,
        const char              *label
)
{
        struct usb_device       *udev = urb->dev;
        int                     max = urb->transfer_buffer_length;
        struct completion       completion;
        int                     retval = 0;
        unsigned long           expire;

        urb->context = &completion;
        while (retval == 0 && iterations-- > 0) {
                init_completion(&completion);
                if (usb_pipeout(urb->pipe)) {
                        simple_fill_buf(urb);
                        urb->transfer_flags |= URB_ZERO_PACKET;
                }
                retval = usb_submit_urb(urb, GFP_KERNEL);
                if (retval != 0)
                        break;

                expire = msecs_to_jiffies(SIMPLE_IO_TIMEOUT);
                if (!wait_for_completion_timeout(&completion, expire)) {
                        usb_kill_urb(urb);
                        retval = (urb->status == -ENOENT ?
                                  -ETIMEDOUT : urb->status);
                } else {
                        retval = urb->status;
                }

                urb->dev = udev;
                if (retval == 0 && usb_pipein(urb->pipe))
                        retval = simple_check_buf(tdev, urb);

                if (vary) {
                        int     len = urb->transfer_buffer_length;

                        len += vary;
                        len %= max;
                        if (len == 0)
                                len = (vary < max) ? vary : max;
                        urb->transfer_buffer_length = len;
                }

                /* FIXME if endpoint halted, clear halt (and log) */
        }
        urb->transfer_buffer_length = max;

        if (expected != retval)
                dev_err(&udev->dev,
                        "%s failed, iterations left %d, status %d (not %d)\n",
                                label, iterations, retval, expected);
        return retval;
}


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

/* We use scatterlist primitives to test queued I/O.
 * Yes, this also tests the scatterlist primitives.
 */

static void free_sglist(struct scatterlist *sg, int nents)
{
        unsigned                i;

        if (!sg)
                return;
        for (i = 0; i < nents; i++) {
                if (!sg_page(&sg[i]))
                        continue;
                kfree(sg_virt(&sg[i]));
        }
        kfree(sg);
}

static struct scatterlist *
alloc_sglist(int nents, int max, int vary, struct usbtest_dev *dev, int pipe)
{
        struct scatterlist      *sg;
        unsigned                i;
        unsigned                size = max;
        unsigned                maxpacket =
                get_maxpacket(interface_to_usbdev(dev->intf), pipe);

        if (max == 0)
                return NULL;

        sg = kmalloc_array(nents, sizeof(*sg), GFP_KERNEL);
        if (!sg)
                return NULL;
        sg_init_table(sg, nents);

        for (i = 0; i < nents; i++) {
                char            *buf;
                unsigned        j;

                buf = kzalloc(size, GFP_KERNEL);
                if (!buf) {
                        free_sglist(sg, i);
                        return NULL;
                }

                /* kmalloc pages are always physically contiguous! */
                sg_set_buf(&sg[i], buf, size);

                switch (pattern) {
                case 0:
                        /* already zeroed */
                        break;
                case 1:
                        for (j = 0; j < size; j++)
                                *buf++ = (u8) ((j % maxpacket) % 63);
                        break;
                }

                if (vary) {
                        size += vary;
                        size %= max;
                        if (size == 0)
                                size = (vary < max) ? vary : max;
                }
        }

        return sg;
}

static void sg_timeout(unsigned long _req)
{
        struct usb_sg_request   *req = (struct usb_sg_request *) _req;

        req->status = -ETIMEDOUT;
        usb_sg_cancel(req);
}

static int perform_sglist(
        struct usbtest_dev      *tdev,
        unsigned                iterations,
        int                     pipe,
        struct usb_sg_request   *req,
        struct scatterlist      *sg,
        int                     nents
)
{
        struct usb_device       *udev = testdev_to_usbdev(tdev);
        int                     retval = 0;
        struct timer_list       sg_timer;

        setup_timer_on_stack(&sg_timer, sg_timeout, (unsigned long) req);

        while (retval == 0 && iterations-- > 0) {
                retval = usb_sg_init(req, udev, pipe,
                                (udev->speed == USB_SPEED_HIGH)
                                        ? (INTERRUPT_RATE << 3)
                                        : INTERRUPT_RATE,
                                sg, nents, 0, GFP_KERNEL);

                if (retval)
                        break;
                mod_timer(&sg_timer, jiffies +
                                msecs_to_jiffies(SIMPLE_IO_TIMEOUT));
                usb_sg_wait(req);
                del_timer_sync(&sg_timer);
                retval = req->status;

                /* FIXME check resulting data pattern */

                /* FIXME if endpoint halted, clear halt (and log) */
        }

        /* FIXME for unlink or fault handling tests, don't report
         * failure if retval is as we expected ...
         */
        if (retval)
                ERROR(tdev, "perform_sglist failed, "
                                "iterations left %d, status %d\n",
                                iterations, retval);
        return retval;
}


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

/* unqueued control message testing
 *
 * there's a nice set of device functional requirements in chapter 9 of the
 * usb 2.0 spec, which we can apply to ANY device, even ones that don't use
 * special test firmware.
 *
 * we know the device is configured (or suspended) by the time it's visible
 * through usbfs.  we can't change that, so we won't test enumeration (which
 * worked 'well enough' to get here, this time), power management (ditto),
 * or remote wakeup (which needs human interaction).
 */

static unsigned realworld = 1;
module_param(realworld, uint, 0);
MODULE_PARM_DESC(realworld, "clear to demand stricter spec compliance");

static int get_altsetting(struct usbtest_dev *dev)
{
        struct usb_interface    *iface = dev->intf;
        struct usb_device       *udev = interface_to_usbdev(iface);
        int                     retval;

        retval = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
                        USB_REQ_GET_INTERFACE, USB_DIR_IN|USB_RECIP_INTERFACE,
                        0, iface->altsetting[0].desc.bInterfaceNumber,
                        dev->buf, 1, USB_CTRL_GET_TIMEOUT);
        switch (retval) {
        case 1:
                return dev->buf[0];
        case 0:
                retval = -ERANGE;
                /* FALLTHROUGH */
        default:
                return retval;
        }
}

static int set_altsetting(struct usbtest_dev *dev, int alternate)
{
        struct usb_interface            *iface = dev->intf;
        struct usb_device               *udev;

        if (alternate < 0 || alternate >= 256)
                return -EINVAL;

        udev = interface_to_usbdev(iface);
        return usb_set_interface(udev,
                        iface->altsetting[0].desc.bInterfaceNumber,
                        alternate);
}

static int is_good_config(struct usbtest_dev *tdev, int len)
{
        struct usb_config_descriptor    *config;

        if (len < sizeof(*config))
                return 0;
        config = (struct usb_config_descriptor *) tdev->buf;

        switch (config->bDescriptorType) {
        case USB_DT_CONFIG:
        case USB_DT_OTHER_SPEED_CONFIG:
                if (config->bLength != 9) {
                        ERROR(tdev, "bogus config descriptor length\n");
                        return 0;
                }
                /* this bit 'must be 1' but often isn't */
                if (!realworld && !(config->bmAttributes & 0x80)) {
                        ERROR(tdev, "high bit of config attributes not set\n");
                        return 0;
                }
                if (config->bmAttributes & 0x1f) {      /* reserved == 0 */
                        ERROR(tdev, "reserved config bits set\n");
                        return 0;
                }
                break;
        default:
                return 0;
        }

        if (le16_to_cpu(config->wTotalLength) == len)   /* read it all */
                return 1;
        if (le16_to_cpu(config->wTotalLength) >= TBUF_SIZE)     /* max partial read */
                return 1;
        ERROR(tdev, "bogus config descriptor read size\n");
        return 0;
}

static int is_good_ext(struct usbtest_dev *tdev, u8 *buf)
{
        struct usb_ext_cap_descriptor *ext;
        u32 attr;

        ext = (struct usb_ext_cap_descriptor *) buf;

        if (ext->bLength != USB_DT_USB_EXT_CAP_SIZE) {
                ERROR(tdev, "bogus usb 2.0 extension descriptor length\n");
                return 0;
        }

        attr = le32_to_cpu(ext->bmAttributes);
        /* bits[1:15] is used and others are reserved */
        if (attr & ~0xfffe) {   /* reserved == 0 */
                ERROR(tdev, "reserved bits set\n");
                return 0;
        }

        return 1;
}

static int is_good_ss_cap(struct usbtest_dev *tdev, u8 *buf)
{
        struct usb_ss_cap_descriptor *ss;

        ss = (struct usb_ss_cap_descriptor *) buf;

        if (ss->bLength != USB_DT_USB_SS_CAP_SIZE) {
                ERROR(tdev, "bogus superspeed device capability descriptor length\n");
                return 0;
        }

        /*
         * only bit[1] of bmAttributes is used for LTM and others are
         * reserved
         */
        if (ss->bmAttributes & ~0x02) { /* reserved == 0 */
                ERROR(tdev, "reserved bits set in bmAttributes\n");
                return 0;
        }

        /* bits[0:3] of wSpeedSupported is used and others are reserved */
        if (le16_to_cpu(ss->wSpeedSupported) & ~0x0f) { /* reserved == 0 */
                ERROR(tdev, "reserved bits set in wSpeedSupported\n");
                return 0;
        }

        return 1;
}

static int is_good_con_id(struct usbtest_dev *tdev, u8 *buf)
{
        struct usb_ss_container_id_descriptor *con_id;

        con_id = (struct usb_ss_container_id_descriptor *) buf;

        if (con_id->bLength != USB_DT_USB_SS_CONTN_ID_SIZE) {
                ERROR(tdev, "bogus container id descriptor length\n");
                return 0;
        }

        if (con_id->bReserved) {        /* reserved == 0 */
                ERROR(tdev, "reserved bits set\n");
                return 0;
        }

        return 1;
}

/* sanity test for standard requests working with usb_control_mesg() and some
 * of the utility functions which use it.
 *
 * this doesn't test how endpoint halts behave or data toggles get set, since
 * we won't do I/O to bulk/interrupt endpoints here (which is how to change
 * halt or toggle).  toggle testing is impractical without support from hcds.
 *
 * this avoids failing devices linux would normally work with, by not testing
 * config/altsetting operations for devices that only support their defaults.
 * such devices rarely support those needless operations.
 *
 * NOTE that since this is a sanity test, it's not examining boundary cases
 * to see if usbcore, hcd, and device all behave right.  such testing would
 * involve varied read sizes and other operation sequences.
 */
static int ch9_postconfig(struct usbtest_dev *dev)
{
        struct usb_interface    *iface = dev->intf;
        struct usb_device       *udev = interface_to_usbdev(iface);
        int                     i, alt, retval;

        /* [9.2.3] if there's more than one altsetting, we need to be able to
         * set and get each one.  mostly trusts the descriptors from usbcore.
         */
        for (i = 0; i < iface->num_altsetting; i++) {

                /* 9.2.3 constrains the range here */
                alt = iface->altsetting[i].desc.bAlternateSetting;
                if (alt < 0 || alt >= iface->num_altsetting) {
                        dev_err(&iface->dev,
                                        "invalid alt [%d].bAltSetting = %d\n",
                                        i, alt);
                }

                /* [real world] get/set unimplemented if there's only one */
                if (realworld && iface->num_altsetting == 1)
                        continue;

                /* [9.4.10] set_interface */
                retval = set_altsetting(dev, alt);
                if (retval) {
                        dev_err(&iface->dev, "can't set_interface = %d, %d\n",
                                        alt, retval);
                        return retval;
                }

                /* [9.4.4] get_interface always works */
                retval = get_altsetting(dev);
                if (retval != alt) {
                        dev_err(&iface->dev, "get alt should be %d, was %d\n",
                                        alt, retval);
                        return (retval < 0) ? retval : -EDOM;
                }

        }

        /* [real world] get_config unimplemented if there's only one */
        if (!realworld || udev->descriptor.bNumConfigurations != 1) {
                int     expected = udev->actconfig->desc.bConfigurationValue;

                /* [9.4.2] get_configuration always works
                 * ... although some cheap devices (like one TI Hub I've got)
                 * won't return config descriptors except before set_config.
                 */
                retval = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
                                USB_REQ_GET_CONFIGURATION,
                                USB_DIR_IN | USB_RECIP_DEVICE,
                                0, 0, dev->buf, 1, USB_CTRL_GET_TIMEOUT);
                if (retval != 1 || dev->buf[0] != expected) {
                        dev_err(&iface->dev, "get config --> %d %d (1 %d)\n",
                                retval, dev->buf[0], expected);
                        return (retval < 0) ? retval : -EDOM;
                }
        }

        /* there's always [9.4.3] a device descriptor [9.6.1] */
        retval = usb_get_descriptor(udev, USB_DT_DEVICE, 0,
                        dev->buf, sizeof(udev->descriptor));
        if (retval != sizeof(udev->descriptor)) {
                dev_err(&iface->dev, "dev descriptor --> %d\n", retval);
                return (retval < 0) ? retval : -EDOM;
        }

        /*
         * there's always [9.4.3] a bos device descriptor [9.6.2] in USB
         * 3.0 spec
         */
        if (le16_to_cpu(udev->descriptor.bcdUSB) >= 0x0210) {
                struct usb_bos_descriptor *bos = NULL;
                struct usb_dev_cap_header *header = NULL;
                unsigned total, num, length;
                u8 *buf;

                retval = usb_get_descriptor(udev, USB_DT_BOS, 0, dev->buf,
                                sizeof(*udev->bos->desc));
                if (retval != sizeof(*udev->bos->desc)) {
                        dev_err(&iface->dev, "bos descriptor --> %d\n", retval);
                        return (retval < 0) ? retval : -EDOM;
                }

                bos = (struct usb_bos_descriptor *)dev->buf;
                total = le16_to_cpu(bos->wTotalLength);
                num = bos->bNumDeviceCaps;

                if (total > TBUF_SIZE)
                        total = TBUF_SIZE;

                /*
                 * get generic device-level capability descriptors [9.6.2]
                 * in USB 3.0 spec
                 */
                retval = usb_get_descriptor(udev, USB_DT_BOS, 0, dev->buf,
                                total);
                if (retval != total) {
                        dev_err(&iface->dev, "bos descriptor set --> %d\n",
                                        retval);
                        return (retval < 0) ? retval : -EDOM;
                }

                length = sizeof(*udev->bos->desc);
                buf = dev->buf;
                for (i = 0; i < num; i++) {
                        buf += length;
                        if (buf + sizeof(struct usb_dev_cap_header) >
                                        dev->buf + total)
                                break;

                        header = (struct usb_dev_cap_header *)buf;
                        length = header->bLength;

                        if (header->bDescriptorType !=
                                        USB_DT_DEVICE_CAPABILITY) {
                                dev_warn(&udev->dev, "not device capability descriptor, skip\n");
                                continue;
                        }

                        switch (header->bDevCapabilityType) {
                        case USB_CAP_TYPE_EXT:
                                if (buf + USB_DT_USB_EXT_CAP_SIZE >
                                                dev->buf + total ||
                                                !is_good_ext(dev, buf)) {
                                        dev_err(&iface->dev, "bogus usb 2.0 extension descriptor\n");
                                        return -EDOM;
                                }
                                break;
                        case USB_SS_CAP_TYPE:
                                if (buf + USB_DT_USB_SS_CAP_SIZE >
                                                dev->buf + total ||
                                                !is_good_ss_cap(dev, buf)) {
                                        dev_err(&iface->dev, "bogus superspeed device capability descriptor\n");
                                        return -EDOM;
                                }
                                break;
                        case CONTAINER_ID_TYPE:
                                if (buf + USB_DT_USB_SS_CONTN_ID_SIZE >
                                                dev->buf + total ||
                                                !is_good_con_id(dev, buf)) {
                                        dev_err(&iface->dev, "bogus container id descriptor\n");
                                        return -EDOM;
                                }
                                break;
                        default:
                                break;
                        }
                }
        }

        /* there's always [9.4.3] at least one config descriptor [9.6.3] */
        for (i = 0; i < udev->descriptor.bNumConfigurations; i++) {
                retval = usb_get_descriptor(udev, USB_DT_CONFIG, i,
                                dev->buf, TBUF_SIZE);
                if (!is_good_config(dev, retval)) {
                        dev_err(&iface->dev,
                                        "config [%d] descriptor --> %d\n",
                                        i, retval);
                        return (retval < 0) ? retval : -EDOM;
                }

                /* FIXME cross-checking udev->config[i] to make sure usbcore
                 * parsed it right (etc) would be good testing paranoia
                 */
        }

        /* and sometimes [9.2.6.6] speed dependent descriptors */
        if (le16_to_cpu(udev->descriptor.bcdUSB) == 0x0200) {
                struct usb_qualifier_descriptor *d = NULL;

                /* device qualifier [9.6.2] */
                retval = usb_get_descriptor(udev,
                                USB_DT_DEVICE_QUALIFIER, 0, dev->buf,
                                sizeof(struct usb_qualifier_descriptor));
                if (retval == -EPIPE) {
                        if (udev->speed == USB_SPEED_HIGH) {
                                dev_err(&iface->dev,
                                                "hs dev qualifier --> %d\n",
                                                retval);
                                return (retval < 0) ? retval : -EDOM;
                        }
                        /* usb2.0 but not high-speed capable; fine */
                } else if (retval != sizeof(struct usb_qualifier_descriptor)) {
                        dev_err(&iface->dev, "dev qualifier --> %d\n", retval);
                        return (retval < 0) ? retval : -EDOM;
                } else
                        d = (struct usb_qualifier_descriptor *) dev->buf;

                /* might not have [9.6.2] any other-speed configs [9.6.4] */
                if (d) {
                        unsigned max = d->bNumConfigurations;

                        for (i = 0; i < max; i++) {
                                retval = usb_get_descriptor(udev,
                                        USB_DT_OTHER_SPEED_CONFIG, i,
                                        dev->buf, TBUF_SIZE);
                                if (!is_good_config(dev, retval)) {
                                        dev_err(&iface->dev,
                                                "other speed config --> %d\n",
                                                retval);
                                        return (retval < 0) ? retval : -EDOM;
                                }
                        }
                }
        }
        /* FIXME fetch strings from at least the device descriptor */

        /* [9.4.5] get_status always works */
        retval = usb_get_status(udev, USB_RECIP_DEVICE, 0, dev->buf);
        if (retval) {
                dev_err(&iface->dev, "get dev status --> %d\n", retval);
                return retval;
        }

        /* FIXME configuration.bmAttributes says if we could try to set/clear
         * the device's remote wakeup feature ... if we can, test that here
         */

        retval = usb_get_status(udev, USB_RECIP_INTERFACE,
                        iface->altsetting[0].desc.bInterfaceNumber, dev->buf);
        if (retval) {
                dev_err(&iface->dev, "get interface status --> %d\n", retval);
                return retval;
        }
        /* FIXME get status for each endpoint in the interface */

        return 0;
}

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

/* use ch9 requests to test whether:
 *   (a) queues work for control, keeping N subtests queued and
 *       active (auto-resubmit) for M loops through the queue.
 *   (b) protocol stalls (control-only) will autorecover.
 *       it's not like bulk/intr; no halt clearing.
 *   (c) short control reads are reported and handled.
 *   (d) queues are always processed in-order
 */

struct ctrl_ctx {
        spinlock_t              lock;
        struct usbtest_dev      *dev;
        struct completion       complete;
        unsigned                count;
        unsigned                pending;
        int                     status;
        struct urb              **urb;
        struct usbtest_param_32 *param;
        int                     last;
};

#define NUM_SUBCASES    16              /* how many test subcases here? */

struct subcase {
        struct usb_ctrlrequest  setup;
        int                     number;
        int                     expected;
};

static void ctrl_complete(struct urb *urb)
{
        struct ctrl_ctx         *ctx = urb->context;
        struct usb_ctrlrequest  *reqp;
        struct subcase          *subcase;
        int                     status = urb->status;

        reqp = (struct usb_ctrlrequest *)urb->setup_packet;
        subcase = container_of(reqp, struct subcase, setup);

        spin_lock(&ctx->lock);
        ctx->count--;
        ctx->pending--;

        /* queue must transfer and complete in fifo order, unless
         * usb_unlink_urb() is used to unlink something not at the
         * physical queue head (not tested).
         */
        if (subcase->number > 0) {
                if ((subcase->number - ctx->last) != 1) {
                        ERROR(ctx->dev,
                                "subcase %d completed out of order, last %d\n",
                                subcase->number, ctx->last);
                        status = -EDOM;
                        ctx->last = subcase->number;
                        goto error;
                }
        }
        ctx->last = subcase->number;

        /* succeed or fault in only one way? */
        if (status == subcase->expected)
                status = 0;

        /* async unlink for cleanup? */
        else if (status != -ECONNRESET) {

                /* some faults are allowed, not required */
                if (subcase->expected > 0 && (
                          ((status == -subcase->expected        /* happened */
                           || status == 0))))                   /* didn't */
                        status = 0;
                /* sometimes more than one fault is allowed */
                else if (subcase->number == 12 && status == -EPIPE)
                        status = 0;
                else
                        ERROR(ctx->dev, "subtest %d error, status %d\n",
                                        subcase->number, status);
        }

        /* unexpected status codes mean errors; ideally, in hardware */
        if (status) {
error:
                if (ctx->status == 0) {
                        int             i;

                        ctx->status = status;
                        ERROR(ctx->dev, "control queue %02x.%02x, err %d, "
                                        "%d left, subcase %d, len %d/%d\n",
                                        reqp->bRequestType, reqp->bRequest,
                                        status, ctx->count, subcase->number,
                                        urb->actual_length,
                                        urb->transfer_buffer_length);

                        /* FIXME this "unlink everything" exit route should
                         * be a separate test case.
                         */

                        /* unlink whatever's still pending */
                        for (i = 1; i < ctx->param->sglen; i++) {
                                struct urb *u = ctx->urb[
                                                        (i + subcase->number)
                                                        % ctx->param->sglen];

                                if (u == urb || !u->dev)
                                        continue;
                                spin_unlock(&ctx->lock);
                                status = usb_unlink_urb(u);
                                spin_lock(&ctx->lock);
                                switch (status) {
                                case -EINPROGRESS:
                                case -EBUSY:
                                case -EIDRM:
                                        continue;
                                default:
                                        ERROR(ctx->dev, "urb unlink --> %d\n",
                                                        status);
                                }
                        }
                        status = ctx->status;
                }
        }

        /* resubmit if we need to, else mark this as done */
        if ((status == 0) && (ctx->pending < ctx->count)) {
                status = usb_submit_urb(urb, GFP_ATOMIC);
                if (status != 0) {
                        ERROR(ctx->dev,
                                "can't resubmit ctrl %02x.%02x, err %d\n",
                                reqp->bRequestType, reqp->bRequest, status);
                        urb->dev = NULL;
                } else
                        ctx->pending++;
        } else
                urb->dev = NULL;

        /* signal completion when nothing's queued */
        if (ctx->pending == 0)
                complete(&ctx->complete);
        spin_unlock(&ctx->lock);
}

static int
test_ctrl_queue(struct usbtest_dev *dev, struct usbtest_param_32 *param)
{
        struct usb_device       *udev = testdev_to_usbdev(dev);
        struct urb              **urb;
        struct ctrl_ctx         context;
        int                     i;

        if (param->sglen == 0 || param->iterations > UINT_MAX / param->sglen)
                return -EOPNOTSUPP;

        spin_lock_init(&context.lock);
        context.dev = dev;
        init_completion(&context.complete);
        context.count = param->sglen * param->iterations;
        context.pending = 0;
        context.status = -ENOMEM;
        context.param = param;
        context.last = -1;

        /* allocate and init the urbs we'll queue.
         * as with bulk/intr sglists, sglen is the queue depth; it also
         * controls which subtests run (more tests than sglen) or rerun.
         */
        urb = kcalloc(param->sglen, sizeof(struct urb *), GFP_KERNEL);
        if (!urb)
                return -ENOMEM;
        for (i = 0; i < param->sglen; i++) {
                int                     pipe = usb_rcvctrlpipe(udev, 0);
                unsigned                len;
                struct urb              *u;
                struct usb_ctrlrequest  req;
                struct subcase          *reqp;

                /* sign of this variable means:
                 *  -: tested code must return this (negative) error code
                 *  +: tested code may return this (negative too) error code
                 */
                int                     expected = 0;

                /* requests here are mostly expected to succeed on any
                 * device, but some are chosen to trigger protocol stalls
                 * or short reads.
                 */
                memset(&req, 0, sizeof(req));
                req.bRequest = USB_REQ_GET_DESCRIPTOR;
                req.bRequestType = USB_DIR_IN|USB_RECIP_DEVICE;

                switch (i % NUM_SUBCASES) {
                case 0:         /* get device descriptor */
                        req.wValue = cpu_to_le16(USB_DT_DEVICE << 8);
                        len = sizeof(struct usb_device_descriptor);
                        break;
                case 1:         /* get first config descriptor (only) */
                        req.wValue = cpu_to_le16((USB_DT_CONFIG << 8) | 0);
                        len = sizeof(struct usb_config_descriptor);
                        break;
                case 2:         /* get altsetting (OFTEN STALLS) */
                        req.bRequest = USB_REQ_GET_INTERFACE;
                        req.bRequestType = USB_DIR_IN|USB_RECIP_INTERFACE;
                        /* index = 0 means first interface */
                        len = 1;
                        expected = EPIPE;
                        break;
                case 3:         /* get interface status */
                        req.bRequest = USB_REQ_GET_STATUS;
                        req.bRequestType = USB_DIR_IN|USB_RECIP_INTERFACE;
                        /* interface 0 */
                        len = 2;
                        break;
                case 4:         /* get device status */
                        req.bRequest = USB_REQ_GET_STATUS;
                        req.bRequestType = USB_DIR_IN|USB_RECIP_DEVICE;
                        len = 2;
                        break;
                case 5:         /* get device qualifier (MAY STALL) */
                        req.wValue = cpu_to_le16 (USB_DT_DEVICE_QUALIFIER << 8);
                        len = sizeof(struct usb_qualifier_descriptor);
                        if (udev->speed != USB_SPEED_HIGH)
                                expected = EPIPE;
                        break;
                case 6:         /* get first config descriptor, plus interface */
                        req.wValue = cpu_to_le16((USB_DT_CONFIG << 8) | 0);
                        len = sizeof(struct usb_config_descriptor);
                        len += sizeof(struct usb_interface_descriptor);
                        break;
                case 7:         /* get interface descriptor (ALWAYS STALLS) */
                        req.wValue = cpu_to_le16 (USB_DT_INTERFACE << 8);
                        /* interface == 0 */
                        len = sizeof(struct usb_interface_descriptor);
                        expected = -EPIPE;
                        break;
                /* NOTE: two consecutive stalls in the queue here.
                 *  that tests fault recovery a bit more aggressively. */
                case 8:         /* clear endpoint halt (MAY STALL) */
                        req.bRequest = USB_REQ_CLEAR_FEATURE;
                        req.bRequestType = USB_RECIP_ENDPOINT;
                        /* wValue 0 == ep halt */
                        /* wIndex 0 == ep0 (shouldn't halt!) */
                        len = 0;
                        pipe = usb_sndctrlpipe(udev, 0);
                        expected = EPIPE;
                        break;
                case 9:         /* get endpoint status */
                        req.bRequest = USB_REQ_GET_STATUS;
                        req.bRequestType = USB_DIR_IN|USB_RECIP_ENDPOINT;
                        /* endpoint 0 */
                        len = 2;
                        break;
                case 10:        /* trigger short read (EREMOTEIO) */
                        req.wValue = cpu_to_le16((USB_DT_CONFIG << 8) | 0);
                        len = 1024;
                        expected = -EREMOTEIO;
                        break;
                /* NOTE: two consecutive _different_ faults in the queue. */
                case 11:        /* get endpoint descriptor (ALWAYS STALLS) */
                        req.wValue = cpu_to_le16(USB_DT_ENDPOINT << 8);
                        /* endpoint == 0 */
                        len = sizeof(struct usb_interface_descriptor);
                        expected = EPIPE;
                        break;
                /* NOTE: sometimes even a third fault in the queue! */
                case 12:        /* get string 0 descriptor (MAY STALL) */
                        req.wValue = cpu_to_le16(USB_DT_STRING << 8);
                        /* string == 0, for language IDs */
                        len = sizeof(struct usb_interface_descriptor);
                        /* may succeed when > 4 languages */
                        expected = EREMOTEIO;   /* or EPIPE, if no strings */
                        break;
                case 13:        /* short read, resembling case 10 */
                        req.wValue = cpu_to_le16((USB_DT_CONFIG << 8) | 0);
                        /* last data packet "should" be DATA1, not DATA0 */
                        if (udev->speed == USB_SPEED_SUPER)
                                len = 1024 - 512;
                        else
                                len = 1024 - udev->descriptor.bMaxPacketSize0;
                        expected = -EREMOTEIO;
                        break;
                case 14:        /* short read; try to fill the last packet */
                        req.wValue = cpu_to_le16((USB_DT_DEVICE << 8) | 0);
                        /* device descriptor size == 18 bytes */
                        len = udev->descriptor.bMaxPacketSize0;
                        if (udev->speed == USB_SPEED_SUPER)
                                len = 512;
                        switch (len) {
                        case 8:
                                len = 24;
                                break;
                        case 16:
                                len = 32;
                                break;
                        }
                        expected = -EREMOTEIO;
                        break;
                case 15:
                        req.wValue = cpu_to_le16(USB_DT_BOS << 8);
                        if (udev->bos)
                                len = le16_to_cpu(udev->bos->desc->wTotalLength);
                        else
                                len = sizeof(struct usb_bos_descriptor);
                        if (le16_to_cpu(udev->descriptor.bcdUSB) < 0x0201)
                                expected = -EPIPE;
                        break;
                default:
                        ERROR(dev, "bogus number of ctrl queue testcases!\n");
                        context.status = -EINVAL;
                        goto cleanup;
                }
                req.wLength = cpu_to_le16(len);
                urb[i] = u = simple_alloc_urb(udev, pipe, len, 0);
                if (!u)
                        goto cleanup;

                reqp = kmalloc(sizeof(*reqp), GFP_KERNEL);
                if (!reqp)
                        goto cleanup;
                reqp->setup = req;
                reqp->number = i % NUM_SUBCASES;
                reqp->expected = expected;
                u->setup_packet = (char *) &reqp->setup;

                u->context = &context;
                u->complete = ctrl_complete;
        }

        /* queue the urbs */
        context.urb = urb;
        spin_lock_irq(&context.lock);
        for (i = 0; i < param->sglen; i++) {
                context.status = usb_submit_urb(urb[i], GFP_ATOMIC);
                if (context.status != 0) {
                        ERROR(dev, "can't submit urb[%d], status %d\n",
                                        i, context.status);
                        context.count = context.pending;
                        break;
                }
                context.pending++;
        }
        spin_unlock_irq(&context.lock);

        /* FIXME  set timer and time out; provide a disconnect hook */

        /* wait for the last one to complete */
        if (context.pending > 0)
                wait_for_completion(&context.complete);

cleanup:
        for (i = 0; i < param->sglen; i++) {
                if (!urb[i])
                        continue;
                urb[i]->dev = udev;
                kfree(urb[i]->setup_packet);
                simple_free_urb(urb[i]);
        }
        kfree(urb);
        return context.status;
}
#undef NUM_SUBCASES


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

static void unlink1_callback(struct urb *urb)
{
        int     status = urb->status;

        /* we "know" -EPIPE (stall) never happens */
        if (!status)
                status = usb_submit_urb(urb, GFP_ATOMIC);
        if (status) {
                urb->status = status;
                complete(urb->context);
        }
}

static int unlink1(struct usbtest_dev *dev, int pipe, int size, int async)
{
        struct urb              *urb;
        struct completion       completion;
        int                     retval = 0;

        init_completion(&completion);
        urb = simple_alloc_urb(testdev_to_usbdev(dev), pipe, size, 0);
        if (!urb)
                return -ENOMEM;
        urb->context = &completion;
        urb->complete = unlink1_callback;

        if (usb_pipeout(urb->pipe)) {
                simple_fill_buf(urb);
                urb->transfer_flags |= URB_ZERO_PACKET;
        }

        /* keep the endpoint busy.  there are lots of hc/hcd-internal
         * states, and testing should get to all of them over time.
         *
         * FIXME want additional tests for when endpoint is STALLing
         * due to errors, or is just NAKing requests.
         */
        retval = usb_submit_urb(urb, GFP_KERNEL);
        if (retval != 0) {
                dev_err(&dev->intf->dev, "submit fail %d\n", retval);
                return retval;
        }

        /* unlinking that should always work.  variable delay tests more
         * hcd states and code paths, even with little other system load.
         */
        msleep(jiffies % (2 * INTERRUPT_RATE));
        if (async) {
                while (!completion_done(&completion)) {
                        retval = usb_unlink_urb(urb);

                        if (retval == 0 && usb_pipein(urb->pipe))
                                retval = simple_check_buf(dev, urb);

                        switch (retval) {
                        case -EBUSY:
                        case -EIDRM:
                                /* we can't unlink urbs while they're completing
                                 * or if they've completed, and we haven't
                                 * resubmitted. "normal" drivers would prevent
                                 * resubmission, but since we're testing unlink
                                 * paths, we can't.
                                 */
                                ERROR(dev, "unlink retry\n");
                                continue;
                        case 0:
                        case -EINPROGRESS:
                                break;

                        default:
                                dev_err(&dev->intf->dev,
                                        "unlink fail %d\n", retval);
                                return retval;
                        }

                        break;
                }
        } else
                usb_kill_urb(urb);

        wait_for_completion(&completion);
        retval = urb->status;
        simple_free_urb(urb);

        if (async)
                return (retval == -ECONNRESET) ? 0 : retval - 1000;
        else
                return (retval == -ENOENT || retval == -EPERM) ?
                                0 : retval - 2000;
}

static int unlink_simple(struct usbtest_dev *dev, int pipe, int len)
{
        int                     retval = 0;

        /* test sync and async paths */
        retval = unlink1(dev, pipe, len, 1);
        if (!retval)
                retval = unlink1(dev, pipe, len, 0);
        return retval;
}

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

struct queued_ctx {
        struct completion       complete;
        atomic_t                pending;
        unsigned                num;
        int                     status;
        struct urb              **urbs;
};

static void unlink_queued_callback(struct urb *urb)
{
        int                     status = urb->status;
        struct queued_ctx       *ctx = urb->context;

        if (ctx->status)
                goto done;
        if (urb == ctx->urbs[ctx->num - 4] || urb == ctx->urbs[ctx->num - 2]) {
                if (status == -ECONNRESET)
                        goto done;
                /* What error should we report if the URB completed normally? */
        }
        if (status != 0)
                ctx->status = status;

 done:
        if (atomic_dec_and_test(&ctx->pending))
                complete(&ctx->complete);
}

static int unlink_queued(struct usbtest_dev *dev, int pipe, unsigned num,
                unsigned size)
{
        struct queued_ctx       ctx;
        struct usb_device       *udev = testdev_to_usbdev(dev);
        void                    *buf;
        dma_addr_t              buf_dma;
        int                     i;
        int                     retval = -ENOMEM;

        init_completion(&ctx.complete);
        atomic_set(&ctx.pending, 1);    /* One more than the actual value */
        ctx.num = num;
        ctx.status = 0;

        buf = usb_alloc_coherent(udev, size, GFP_KERNEL, &buf_dma);
        if (!buf)
                return retval;
        memset(buf, 0, size);

        /* Allocate and init the urbs we'll queue */
        ctx.urbs = kcalloc(num, sizeof(struct urb *), GFP_KERNEL);
        if (!ctx.urbs)
                goto free_buf;
        for (i = 0; i < num; i++) {
                ctx.urbs[i] = usb_alloc_urb(0, GFP_KERNEL);
                if (!ctx.urbs[i])
                        goto free_urbs;
                usb_fill_bulk_urb(ctx.urbs[i], udev, pipe, buf, size,
                                unlink_queued_callback, &ctx);
                ctx.urbs[i]->transfer_dma = buf_dma;
                ctx.urbs[i]->transfer_flags = URB_NO_TRANSFER_DMA_MAP;

                if (usb_pipeout(ctx.urbs[i]->pipe)) {
                        simple_fill_buf(ctx.urbs[i]);
                        ctx.urbs[i]->transfer_flags |= URB_ZERO_PACKET;
                }
        }

        /* Submit all the URBs and then unlink URBs num - 4 and num - 2. */
        for (i = 0; i < num; i++) {
                atomic_inc(&ctx.pending);
                retval = usb_submit_urb(ctx.urbs[i], GFP_KERNEL);
                if (retval != 0) {
                        dev_err(&dev->intf->dev, "submit urbs[%d] fail %d\n",
                                        i, retval);
                        atomic_dec(&ctx.pending);
                        ctx.status = retval;
                        break;
                }
        }
        if (i == num) {
                usb_unlink_urb(ctx.urbs[num - 4]);
                usb_unlink_urb(ctx.urbs[num - 2]);
        } else {
                while (--i >= 0)
                        usb_unlink_urb(ctx.urbs[i]);
        }

        if (atomic_dec_and_test(&ctx.pending))          /* The extra count */
                complete(&ctx.complete);
        wait_for_completion(&ctx.complete);
        retval = ctx.status;

 free_urbs:
        for (i = 0; i < num; i++)
                usb_free_urb(ctx.urbs[i]);
        kfree(ctx.urbs);
 free_buf:
        usb_free_coherent(udev, size, buf, buf_dma);
        return retval;
}

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

static int verify_not_halted(struct usbtest_dev *tdev, int ep, struct urb *urb)
{
        int     retval;
        u16     status;

        /* shouldn't look or act halted */
        retval = usb_get_status(urb->dev, USB_RECIP_ENDPOINT, ep, &status);
        if (retval < 0) {
                ERROR(tdev, "ep %02x couldn't get no-halt status, %d\n",
                                ep, retval);
                return retval;
        }
        if (status != 0) {
                ERROR(tdev, "ep %02x bogus status: %04x != 0\n", ep, status);
                return -EINVAL;
        }
        retval = simple_io(tdev, urb, 1, 0, 0, __func__);
        if (retval != 0)
                return -EINVAL;
        return 0;
}

static int verify_halted(struct usbtest_dev *tdev, int ep, struct urb *urb)
{
        int     retval;
        u16     status;

        /* should look and act halted */
        retval = usb_get_status(urb->dev, USB_RECIP_ENDPOINT, ep, &status);
        if (retval < 0) {
                ERROR(tdev, "ep %02x couldn't get halt status, %d\n",
                                ep, retval);
                return retval;
        }
        if (status != 1) {
                ERROR(tdev, "ep %02x bogus status: %04x != 1\n", ep, status);
                return -EINVAL;
        }
        retval = simple_io(tdev, urb, 1, 0, -EPIPE, __func__);
        if (retval != -EPIPE)
                return -EINVAL;
        retval = simple_io(tdev, urb, 1, 0, -EPIPE, "verify_still_halted");
        if (retval != -EPIPE)
                return -EINVAL;
        return 0;
}

static int test_halt(struct usbtest_dev *tdev, int ep, struct urb *urb)
{
        int     retval;

        /* shouldn't look or act halted now */
        retval = verify_not_halted(tdev, ep, urb);
        if (retval < 0)
                return retval;

        /* set halt (protocol test only), verify it worked */
        retval = usb_control_msg(urb->dev, usb_sndctrlpipe(urb->dev, 0),
                        USB_REQ_SET_FEATURE, USB_RECIP_ENDPOINT,
                        USB_ENDPOINT_HALT, ep,
                        NULL, 0, USB_CTRL_SET_TIMEOUT);
        if (retval < 0) {
                ERROR(tdev, "ep %02x couldn't set halt, %d\n", ep, retval);
                return retval;
        }
        retval = verify_halted(tdev, ep, urb);
        if (retval < 0) {
                int ret;

                /* clear halt anyways, else further tests will fail */
                ret = usb_clear_halt(urb->dev, urb->pipe);
                if (ret)
                        ERROR(tdev, "ep %02x couldn't clear halt, %d\n",
                              ep, ret);

                return retval;
        }

        /* clear halt (tests API + protocol), verify it worked */
        retval = usb_clear_halt(urb->dev, urb->pipe);
        if (retval < 0) {
                ERROR(tdev, "ep %02x couldn't clear halt, %d\n", ep, retval);
                return retval;
        }
        retval = verify_not_halted(tdev, ep, urb);
        if (retval < 0)
                return retval;

        /* NOTE:  could also verify SET_INTERFACE clear halts ... */

        return 0;
}

static int halt_simple(struct usbtest_dev *dev)
{
        int                     ep;
        int                     retval = 0;
        struct urb              *urb;
        struct usb_device       *udev = testdev_to_usbdev(dev);

        if (udev->speed == USB_SPEED_SUPER)
                urb = simple_alloc_urb(udev, 0, 1024, 0);
        else
                urb = simple_alloc_urb(udev, 0, 512, 0);
        if (urb == NULL)
                return -ENOMEM;

        if (dev->in_pipe) {
                ep = usb_pipeendpoint(dev->in_pipe) | USB_DIR_IN;
                urb->pipe = dev->in_pipe;
                retval = test_halt(dev, ep, urb);
                if (retval < 0)
                        goto done;
        }

        if (dev->out_pipe) {
                ep = usb_pipeendpoint(dev->out_pipe);
                urb->pipe = dev->out_pipe;
                retval = test_halt(dev, ep, urb);
        }
done:
        simple_free_urb(urb);
        return retval;
}

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

/* Control OUT tests use the vendor control requests from Intel's
 * USB 2.0 compliance test device:  write a buffer, read it back.
 *
 * Intel's spec only _requires_ that it work for one packet, which
 * is pretty weak.   Some HCDs place limits here; most devices will
 * need to be able to handle more than one OUT data packet.  We'll
 * try whatever we're told to try.
 */
static int ctrl_out(struct usbtest_dev *dev,
                unsigned count, unsigned length, unsigned vary, unsigned offset)
{
        unsigned                i, j, len;
        int                     retval;
        u8                      *buf;
        char                    *what = "?";
        struct usb_device       *udev;

        if (length < 1 || length > 0xffff || vary >= length)
                return -EINVAL;

        buf = kmalloc(length + offset, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        buf += offset;
        udev = testdev_to_usbdev(dev);
        len = length;
        retval = 0;

        /* NOTE:  hardware might well act differently if we pushed it
         * with lots back-to-back queued requests.
         */
        for (i = 0; i < count; i++) {
                /* write patterned data */
                for (j = 0; j < len; j++)
                        buf[j] = (u8)(i + j);
                retval = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
                                0x5b, USB_DIR_OUT|USB_TYPE_VENDOR,
                                0, 0, buf, len, USB_CTRL_SET_TIMEOUT);
                if (retval != len) {
                        what = "write";
                        if (retval >= 0) {
                                ERROR(dev, "ctrl_out, wlen %d (expected %d)\n",
                                                retval, len);
                                retval = -EBADMSG;
                        }
                        break;
                }

                /* read it back -- assuming nothing intervened!!  */
                retval = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
                                0x5c, USB_DIR_IN|USB_TYPE_VENDOR,
                                0, 0, buf, len, USB_CTRL_GET_TIMEOUT);
                if (retval != len) {
                        what = "read";
                        if (retval >= 0) {
                                ERROR(dev, "ctrl_out, rlen %d (expected %d)\n",
                                                retval, len);
                                retval = -EBADMSG;
                        }
                        break;
                }

                /* fail if we can't verify */
                for (j = 0; j < len; j++) {
                        if (buf[j] != (u8)(i + j)) {
                                ERROR(dev, "ctrl_out, byte %d is %d not %d\n",
                                        j, buf[j], (u8)(i + j));
                                retval = -EBADMSG;
                                break;
                        }
                }
                if (retval < 0) {
                        what = "verify";
                        break;
                }

                len += vary;

                /* [real world] the "zero bytes IN" case isn't really used.
                 * hardware can easily trip up in this weird case, since its
                 * status stage is IN, not OUT like other ep0in transfers.
                 */
                if (len > length)
                        len = realworld ? 1 : 0;
        }

        if (retval < 0)
                ERROR(dev, "ctrl_out %s failed, code %d, count %d\n",
                        what, retval, i);

        kfree(buf - offset);
        return retval;
}

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

/* ISO/BULK tests ... mimics common usage
 *  - buffer length is split into N packets (mostly maxpacket sized)
 *  - multi-buffers according to sglen
 */

struct transfer_context {
        unsigned                count;
        unsigned                pending;
        spinlock_t              lock;
        struct completion       done;
        int                     submit_error;
        unsigned long           errors;
        unsigned long           packet_count;
        struct usbtest_dev      *dev;
        bool                    is_iso;
};

static void complicated_callback(struct urb *urb)
{
        struct transfer_context *ctx = urb->context;

        spin_lock(&ctx->lock);
        ctx->count--;

        ctx->packet_count += urb->number_of_packets;
        if (urb->error_count > 0)
                ctx->errors += urb->error_count;
        else if (urb->status != 0)
                ctx->errors += (ctx->is_iso ? urb->number_of_packets : 1);
        else if (urb->actual_length != urb->transfer_buffer_length)
                ctx->errors++;
        else if (check_guard_bytes(ctx->dev, urb) != 0)
                ctx->errors++;

        if (urb->status == 0 && ctx->count > (ctx->pending - 1)
                        && !ctx->submit_error) {
                int status = usb_submit_urb(urb, GFP_ATOMIC);
                switch (status) {
                case 0:
                        goto done;
                default:
                        dev_err(&ctx->dev->intf->dev,
                                        "resubmit err %d\n",
                                        status);
                        /* FALLTHROUGH */
                case -ENODEV:                   /* disconnected */
                case -ESHUTDOWN:                /* endpoint disabled */
                        ctx->submit_error = 1;
                        break;
                }
        }

        ctx->pending--;
        if (ctx->pending == 0) {
                if (ctx->errors)
                        dev_err(&ctx->dev->intf->dev,
                                "during the test, %lu errors out of %lu\n",
                                ctx->errors, ctx->packet_count);
                complete(&ctx->done);
        }
done:
        spin_unlock(&ctx->lock);
}

static struct urb *iso_alloc_urb(
        struct usb_device       *udev,
        int                     pipe,
        struct usb_endpoint_descriptor  *desc,
        long                    bytes,
        unsigned offset
)
{
        struct urb              *urb;
        unsigned                i, maxp, packets;

        if (bytes < 0 || !desc)
                return NULL;
        maxp = 0x7ff & usb_endpoint_maxp(desc);
        maxp *= 1 + (0x3 & (usb_endpoint_maxp(desc) >> 11));
        packets = DIV_ROUND_UP(bytes, maxp);

        urb = usb_alloc_urb(packets, GFP_KERNEL);
        if (!urb)
                return urb;
        urb->dev = udev;
        urb->pipe = pipe;

        urb->number_of_packets = packets;
        urb->transfer_buffer_length = bytes;
        urb->transfer_buffer = usb_alloc_coherent(udev, bytes + offset,
                                                        GFP_KERNEL,
                                                        &urb->transfer_dma);
        if (!urb->transfer_buffer) {
                usb_free_urb(urb);
                return NULL;
        }
        if (offset) {
                memset(urb->transfer_buffer, GUARD_BYTE, offset);
                urb->transfer_buffer += offset;
                urb->transfer_dma += offset;
        }
        /* For inbound transfers use guard byte so that test fails if
                data not correctly copied */
        memset(urb->transfer_buffer,
                        usb_pipein(urb->pipe) ? GUARD_BYTE : 0,
                        bytes);

        for (i = 0; i < packets; i++) {
                /* here, only the last packet will be short */
                urb->iso_frame_desc[i].length = min((unsigned) bytes, maxp);
                bytes -= urb->iso_frame_desc[i].length;

                urb->iso_frame_desc[i].offset = maxp * i;
        }

        urb->complete = complicated_callback;
        /* urb->context = SET BY CALLER */
        urb->interval = 1 << (desc->bInterval - 1);
        urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
        return urb;
}

static int
test_queue(struct usbtest_dev *dev, struct usbtest_param_32 *param,
                int pipe, struct usb_endpoint_descriptor *desc, unsigned offset)
{
        struct transfer_context context;
        struct usb_device       *udev;
        unsigned                i;
        unsigned long           packets = 0;
        int                     status = 0;
        struct urb              *urbs[param->sglen];

        memset(&context, 0, sizeof(context));
        context.count = param->iterations * param->sglen;
        context.dev = dev;
        context.is_iso = !!desc;
        init_completion(&context.done);
        spin_lock_init(&context.lock);

        udev = testdev_to_usbdev(dev);

        for (i = 0; i < param->sglen; i++) {
                if (context.is_iso)
                        urbs[i] = iso_alloc_urb(udev, pipe, desc,
                                        param->length, offset);
                else
                        urbs[i] = complicated_alloc_urb(udev, pipe,
                                        param->length, 0);

                if (!urbs[i]) {
                        status = -ENOMEM;
                        goto fail;
                }
                packets += urbs[i]->number_of_packets;
                urbs[i]->context = &context;
        }
        packets *= param->iterations;

        if (context.is_iso) {
                dev_info(&dev->intf->dev,
                        "iso period %d %sframes, wMaxPacket %d, transactions: %d\n",
                        1 << (desc->bInterval - 1),
                        (udev->speed == USB_SPEED_HIGH) ? "micro" : "",
                        usb_endpoint_maxp(desc) & 0x7ff,
                        1 + (0x3 & (usb_endpoint_maxp(desc) >> 11)));

                dev_info(&dev->intf->dev,
                        "total %lu msec (%lu packets)\n",
                        (packets * (1 << (desc->bInterval - 1)))
                                / ((udev->speed == USB_SPEED_HIGH) ? 8 : 1),
                        packets);
        }

        spin_lock_irq(&context.lock);
        for (i = 0; i < param->sglen; i++) {
                ++context.pending;
                status = usb_submit_urb(urbs[i], GFP_ATOMIC);
                if (status < 0) {
                        ERROR(dev, "submit iso[%d], error %d\n", i, status);
                        if (i == 0) {
                                spin_unlock_irq(&context.lock);
                                goto fail;
                        }

                        simple_free_urb(urbs[i]);
                        urbs[i] = NULL;
                        context.pending--;
                        context.submit_error = 1;
                        break;
                }
        }
        spin_unlock_irq(&context.lock);

        wait_for_completion(&context.done);

        for (i = 0; i < param->sglen; i++) {
                if (urbs[i])
                        simple_free_urb(urbs[i]);
        }
        /*
         * Isochronous transfers are expected to fail sometimes.  As an
         * arbitrary limit, we will report an error if any submissions
         * fail or if the transfer failure rate is > 10%.
         */
        if (status != 0)
                ;
        else if (context.submit_error)
                status = -EACCES;
        else if (context.errors >
                        (context.is_iso ? context.packet_count / 10 : 0))
                status = -EIO;
        return status;

fail:
        for (i = 0; i < param->sglen; i++) {
                if (urbs[i])
                        simple_free_urb(urbs[i]);
        }
        return status;
}

static int test_unaligned_bulk(
        struct usbtest_dev *tdev,
        int pipe,
        unsigned length,
        int iterations,
        unsigned transfer_flags,
        const char *label)
{
        int retval;
        struct urb *urb = usbtest_alloc_urb(testdev_to_usbdev(tdev),
                        pipe, length, transfer_flags, 1, 0, simple_callback);

        if (!urb)
                return -ENOMEM;

        retval = simple_io(tdev, urb, iterations, 0, 0, label);
        simple_free_urb(urb);
        return retval;
}

/* Run tests. */
static int
usbtest_do_ioctl(struct usb_interface *intf, struct usbtest_param_32 *param)
{
        struct usbtest_dev      *dev = usb_get_intfdata(intf);
        struct usb_device       *udev = testdev_to_usbdev(dev);
        struct urb              *urb;
        struct scatterlist      *sg;
        struct usb_sg_request   req;
        unsigned                i;
        int     retval = -EOPNOTSUPP;

        if (param->iterations <= 0)
                return -EINVAL;
        /*
         * Just a bunch of test cases that every HCD is expected to handle.
         *
         * Some may need specific firmware, though it'd be good to have
         * one firmware image to handle all the test cases.
         *
         * FIXME add more tests!  cancel requests, verify the data, control
         * queueing, concurrent read+write threads, and so on.
         */
        switch (param->test_num) {

        case 0:
                dev_info(&intf->dev, "TEST 0:  NOP\n");
                retval = 0;
                break;

        /* Simple non-queued bulk I/O tests */
        case 1:
                if (dev->out_pipe == 0)
                        break;
                dev_info(&intf->dev,
                                "TEST 1:  write %d bytes %u times\n",
                                param->length, param->iterations);
                urb = simple_alloc_urb(udev, dev->out_pipe, param->length, 0);
                if (!urb) {
                        retval = -ENOMEM;
                        break;
                }
                /* FIRMWARE:  bulk sink (maybe accepts short writes) */
                retval = simple_io(dev, urb, param->iterations, 0, 0, "test1");
                simple_free_urb(urb);
                break;
        case 2:
                if (dev->in_pipe == 0)
                        break;
                dev_info(&intf->dev,
                                "TEST 2:  read %d bytes %u times\n",
                                param->length, param->iterations);
                urb = simple_alloc_urb(udev, dev->in_pipe, param->length, 0);
                if (!urb) {
                        retval = -ENOMEM;
                        break;
                }
                /* FIRMWARE:  bulk source (maybe generates short writes) */
                retval = simple_io(dev, urb, param->iterations, 0, 0, "test2");
                simple_free_urb(urb);
                break;
        case 3:
                if (dev->out_pipe == 0 || param->vary == 0)
                        break;
                dev_info(&intf->dev,
                                "TEST 3:  write/%d 0..%d bytes %u times\n",
                                param->vary, param->length, param->iterations);
                urb = simple_alloc_urb(udev, dev->out_pipe, param->length, 0);
                if (!urb) {
                        retval = -ENOMEM;
                        break;
                }
                /* FIRMWARE:  bulk sink (maybe accepts short writes) */
                retval = simple_io(dev, urb, param->iterations, param->vary,
                                        0, "test3");
                simple_free_urb(urb);
                break;
        case 4:
                if (dev->in_pipe == 0 || param->vary == 0)
                        break;
                dev_info(&intf->dev,
                                "TEST 4:  read/%d 0..%d bytes %u times\n",
                                param->vary, param->length, param->iterations);
                urb = simple_alloc_urb(udev, dev->in_pipe, param->length, 0);
                if (!urb) {
                        retval = -ENOMEM;
                        break;
                }
                /* FIRMWARE:  bulk source (maybe generates short writes) */
                retval = simple_io(dev, urb, param->iterations, param->vary,
                                        0, "test4");
                simple_free_urb(urb);
                break;

        /* Queued bulk I/O tests */
        case 5:
                if (dev->out_pipe == 0 || param->sglen == 0)
                        break;
                dev_info(&intf->dev,
                        "TEST 5:  write %d sglists %d entries of %d bytes\n",
                                param->iterations,
                                param->sglen, param->length);
                sg = alloc_sglist(param->sglen, param->length,
                                0, dev, dev->out_pipe);
                if (!sg) {
                        retval = -ENOMEM;
                        break;
                }
                /* FIRMWARE:  bulk sink (maybe accepts short writes) */
                retval = perform_sglist(dev, param->iterations, dev->out_pipe,
                                &req, sg, param->sglen);
                free_sglist(sg, param->sglen);
                break;

        case 6:
                if (dev->in_pipe == 0 || param->sglen == 0)
                        break;
                dev_info(&intf->dev,
                        "TEST 6:  read %d sglists %d entries of %d bytes\n",
                                param->iterations,
                                param->sglen, param->length);
                sg = alloc_sglist(param->sglen, param->length,
                                0, dev, dev->in_pipe);
                if (!sg) {
                        retval = -ENOMEM;
                        break;
                }
                /* FIRMWARE:  bulk source (maybe generates short writes) */
                retval = perform_sglist(dev, param->iterations, dev->in_pipe,
                                &req, sg, param->sglen);
                free_sglist(sg, param->sglen);
                break;
        case 7:
                if (dev->out_pipe == 0 || param->sglen == 0 || param->vary == 0)
                        break;
                dev_info(&intf->dev,
                        "TEST 7:  write/%d %d sglists %d entries 0..%d bytes\n",
                                param->vary, param->iterations,
                                param->sglen, param->length);
                sg = alloc_sglist(param->sglen, param->length,
                                param->vary, dev, dev->out_pipe);
                if (!sg) {
                        retval = -ENOMEM;
                        break;
                }
                /* FIRMWARE:  bulk sink (maybe accepts short writes) */
                retval = perform_sglist(dev, param->iterations, dev->out_pipe,
                                &req, sg, param->sglen);
                free_sglist(sg, param->sglen);
                break;
        case 8:
                if (dev->in_pipe == 0 || param->sglen == 0 || param->vary == 0)
                        break;
                dev_info(&intf->dev,
                        "TEST 8:  read/%d %d sglists %d entries 0..%d bytes\n",
                                param->vary, param->iterations,
                                param->sglen, param->length);
                sg = alloc_sglist(param->sglen, param->length,
                                param->vary, dev, dev->in_pipe);
                if (!sg) {
                        retval = -ENOMEM;
                        break;
                }
                /* FIRMWARE:  bulk source (maybe generates short writes) */
                retval = perform_sglist(dev, param->iterations, dev->in_pipe,
                                &req, sg, param->sglen);
                free_sglist(sg, param->sglen);
                break;

        /* non-queued sanity tests for control (chapter 9 subset) */
        case 9:
                retval = 0;
                dev_info(&intf->dev,
                        "TEST 9:  ch9 (subset) control tests, %d times\n",
                                param->iterations);
                for (i = param->iterations; retval == 0 && i--; /* NOP */)
                        retval = ch9_postconfig(dev);
                if (retval)
                        dev_err(&intf->dev, "ch9 subset failed, "
                                        "iterations left %d\n", i);
                break;

        /* queued control messaging */
        case 10:
                retval = 0;
                dev_info(&intf->dev,
                                "TEST 10:  queue %d control calls, %d times\n",
                                param->sglen,
                                param->iterations);
                retval = test_ctrl_queue(dev, param);
                break;

        /* simple non-queued unlinks (ring with one urb) */
        case 11:
                if (dev->in_pipe == 0 || !param->length)
                        break;
                retval = 0;
                dev_info(&intf->dev, "TEST 11:  unlink %d reads of %d\n",
                                param->iterations, param->length);
                for (i = param->iterations; retval == 0 && i--; /* NOP */)
                        retval = unlink_simple(dev, dev->in_pipe,
                                                param->length);
                if (retval)
                        dev_err(&intf->dev, "unlink reads failed %d, "
                                "iterations left %d\n", retval, i);
                break;
        case 12:
                if (dev->out_pipe == 0 || !param->length)
                        break;
                retval = 0;
                dev_info(&intf->dev, "TEST 12:  unlink %d writes of %d\n",
                                param->iterations, param->length);
                for (i = param->iterations; retval == 0 && i--; /* NOP */)
                        retval = unlink_simple(dev, dev->out_pipe,
                                                param->length);
                if (retval)
                        dev_err(&intf->dev, "unlink writes failed %d, "
                                "iterations left %d\n", retval, i);
                break;

        /* ep halt tests */
        case 13:
                if (dev->out_pipe == 0 && dev->in_pipe == 0)
                        break;
                retval = 0;
                dev_info(&intf->dev, "TEST 13:  set/clear %d halts\n",
                                param->iterations);
                for (i = param->iterations; retval == 0 && i--; /* NOP */)
                        retval = halt_simple(dev);

                if (retval)
                        ERROR(dev, "halts failed, iterations left %d\n", i);
                break;

        /* control write tests */
        case 14:
                if (!dev->info->ctrl_out)
                        break;
                dev_info(&intf->dev, "TEST 14:  %d ep0out, %d..%d vary %d\n",
                                param->iterations,
                                realworld ? 1 : 0, param->length,
                                param->vary);
                retval = ctrl_out(dev, param->iterations,
                                param->length, param->vary, 0);
                break;

        /* iso write tests */
        case 15:
                if (dev->out_iso_pipe == 0 || param->sglen == 0)
                        break;
                dev_info(&intf->dev,
                        "TEST 15:  write %d iso, %d entries of %d bytes\n",
                                param->iterations,
                                param->sglen, param->length);
                /* FIRMWARE:  iso sink */
                retval = test_queue(dev, param,
                                dev->out_iso_pipe, dev->iso_out, 0);
                break;

        /* iso read tests */
        case 16:
                if (dev->in_iso_pipe == 0 || param->sglen == 0)
                        break;
                dev_info(&intf->dev,
                        "TEST 16:  read %d iso, %d entries of %d bytes\n",
                                param->iterations,
                                param->sglen, param->length);
                /* FIRMWARE:  iso source */
                retval = test_queue(dev, param,
                                dev->in_iso_pipe, dev->iso_in, 0);
                break;

        /* FIXME scatterlist cancel (needs helper thread) */

        /* Tests for bulk I/O using DMA mapping by core and odd address */
        case 17:
                if (dev->out_pipe == 0)
                        break;
                dev_info(&intf->dev,
                        "TEST 17:  write odd addr %d bytes %u times core map\n",
                        param->length, param->iterations);

                retval = test_unaligned_bulk(
                                dev, dev->out_pipe,
                                param->length, param->iterations,
                                0, "test17");
                break;

        case 18:
                if (dev->in_pipe == 0)
                        break;
                dev_info(&intf->dev,
                        "TEST 18:  read odd addr %d bytes %u times core map\n",
                        param->length, param->iterations);

                retval = test_unaligned_bulk(
                                dev, dev->in_pipe,
                                param->length, param->iterations,
                                0, "test18");
                break;

        /* Tests for bulk I/O using premapped coherent buffer and odd address */
        case 19:
                if (dev->out_pipe == 0)
                        break;
                dev_info(&intf->dev,
                        "TEST 19:  write odd addr %d bytes %u times premapped\n",
                        param->length, param->iterations);

                retval = test_unaligned_bulk(
                                dev, dev->out_pipe,
                                param->length, param->iterations,
                                URB_NO_TRANSFER_DMA_MAP, "test19");
                break;

        case 20:
                if (dev->in_pipe == 0)
                        break;
                dev_info(&intf->dev,
                        "TEST 20:  read odd addr %d bytes %u times premapped\n",
                        param->length, param->iterations);

                retval = test_unaligned_bulk(
                                dev, dev->in_pipe,
                                param->length, param->iterations,
                                URB_NO_TRANSFER_DMA_MAP, "test20");
                break;

        /* control write tests with unaligned buffer */
        case 21:
                if (!dev->info->ctrl_out)
                        break;
                dev_info(&intf->dev,
                                "TEST 21:  %d ep0out odd addr, %d..%d vary %d\n",
                                param->iterations,
                                realworld ? 1 : 0, param->length,
                                param->vary);
                retval = ctrl_out(dev, param->iterations,
                                param->length, param->vary, 1);
                break;

        /* unaligned iso tests */
        case 22:
                if (dev->out_iso_pipe == 0 || param->sglen == 0)
                        break;
                dev_info(&intf->dev,
                        "TEST 22:  write %d iso odd, %d entries of %d bytes\n",
                                param->iterations,
                                param->sglen, param->length);
                retval = test_queue(dev, param,
                                dev->out_iso_pipe, dev->iso_out, 1);
                break;

        case 23:
                if (dev->in_iso_pipe == 0 || param->sglen == 0)
                        break;
                dev_info(&intf->dev,
                        "TEST 23:  read %d iso odd, %d entries of %d bytes\n",
                                param->iterations,
                                param->sglen, param->length);
                retval = test_queue(dev, param,
                                dev->in_iso_pipe, dev->iso_in, 1);
                break;

        /* unlink URBs from a bulk-OUT queue */
        case 24:
                if (dev->out_pipe == 0 || !param->length || param->sglen < 4)
                        break;
                retval = 0;
                dev_info(&intf->dev, "TEST 24:  unlink from %d queues of "
                                "%d %d-byte writes\n",
                                param->iterations, param->sglen, param->length);
                for (i = param->iterations; retval == 0 && i > 0; --i) {
                        retval = unlink_queued(dev, dev->out_pipe,
                                                param->sglen, param->length);
                        if (retval) {
                                dev_err(&intf->dev,
                                        "unlink queued writes failed %d, "
                                        "iterations left %d\n", retval, i);
                                break;
                        }
                }
                break;

        /* Simple non-queued interrupt I/O tests */
        case 25:
                if (dev->out_int_pipe == 0)
                        break;
                dev_info(&intf->dev,
                                "TEST 25: write %d bytes %u times\n",
                                param->length, param->iterations);
                urb = simple_alloc_urb(udev, dev->out_int_pipe, param->length,
                                dev->int_out->bInterval);
                if (!urb) {
                        retval = -ENOMEM;
                        break;
                }
                /* FIRMWARE: interrupt sink (maybe accepts short writes) */
                retval = simple_io(dev, urb, param->iterations, 0, 0, "test25");
                simple_free_urb(urb);
                break;
        case 26:
                if (dev->in_int_pipe == 0)
                        break;
                dev_info(&intf->dev,
                                "TEST 26: read %d bytes %u times\n",
                                param->length, param->iterations);
                urb = simple_alloc_urb(udev, dev->in_int_pipe, param->length,
                                dev->int_in->bInterval);
                if (!urb) {
                        retval = -ENOMEM;
                        break;
                }
                /* FIRMWARE: interrupt source (maybe generates short writes) */
                retval = simple_io(dev, urb, param->iterations, 0, 0, "test26");
                simple_free_urb(urb);
                break;
        case 27:
                /* We do performance test, so ignore data compare */
                if (dev->out_pipe == 0 || param->sglen == 0 || pattern != 0)
                        break;
                dev_info(&intf->dev,
                        "TEST 27: bulk write %dMbytes\n", (param->iterations *
                        param->sglen * param->length) / (1024 * 1024));
                retval = test_queue(dev, param,
                                dev->out_pipe, NULL, 0);
                break;
        case 28:
                if (dev->in_pipe == 0 || param->sglen == 0 || pattern != 0)
                        break;
                dev_info(&intf->dev,
                        "TEST 28: bulk read %dMbytes\n", (param->iterations *
                        param->sglen * param->length) / (1024 * 1024));
                retval = test_queue(dev, param,
                                dev->in_pipe, NULL, 0);
                break;
        }
        return retval;
}

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

/* We only have this one interface to user space, through usbfs.
 * User mode code can scan usbfs to find N different devices (maybe on
 * different busses) to use when testing, and allocate one thread per
 * test.  So discovery is simplified, and we have no device naming issues.
 *
 * Don't use these only as stress/load tests.  Use them along with with
 * other USB bus activity:  plugging, unplugging, mousing, mp3 playback,
 * video capture, and so on.  Run different tests at different times, in
 * different sequences.  Nothing here should interact with other devices,
 * except indirectly by consuming USB bandwidth and CPU resources for test
 * threads and request completion.  But the only way to know that for sure
 * is to test when HC queues are in use by many devices.
 *
 * WARNING:  Because usbfs grabs udev->dev.sem before calling this ioctl(),
 * it locks out usbcore in certain code paths.  Notably, if you disconnect
 * the device-under-test, hub_wq will wait block forever waiting for the
 * ioctl to complete ... so that usb_disconnect() can abort the pending
 * urbs and then call usbtest_disconnect().  To abort a test, you're best
 * off just killing the userspace task and waiting for it to exit.
 */

static int
usbtest_ioctl(struct usb_interface *intf, unsigned int code, void *buf)
{

        struct usbtest_dev      *dev = usb_get_intfdata(intf);
        struct usbtest_param_64 *param_64 = buf;
        struct usbtest_param_32 temp;
        struct usbtest_param_32 *param_32 = buf;
        struct timespec64 start;
        struct timespec64 end;
        struct timespec64 duration;
        int retval = -EOPNOTSUPP;

        /* FIXME USBDEVFS_CONNECTINFO doesn't say how fast the device is. */

        pattern = mod_pattern;

        if (mutex_lock_interruptible(&dev->lock))
                return -ERESTARTSYS;

        /* FIXME: What if a system sleep starts while a test is running? */

        /* some devices, like ez-usb default devices, need a non-default
         * altsetting to have any active endpoints.  some tests change
         * altsettings; force a default so most tests don't need to check.
         */
        if (dev->info->alt >= 0) {
                if (intf->altsetting->desc.bInterfaceNumber) {
                        retval = -ENODEV;
                        goto free_mutex;
                }
                retval = set_altsetting(dev, dev->info->alt);
                if (retval) {
                        dev_err(&intf->dev,
                                        "set altsetting to %d failed, %d\n",
                                        dev->info->alt, retval);
                        goto free_mutex;
                }
        }

        switch (code) {
        case USBTEST_REQUEST_64:
                temp.test_num = param_64->test_num;
                temp.iterations = param_64->iterations;
                temp.length = param_64->length;
                temp.sglen = param_64->sglen;
                temp.vary = param_64->vary;
                param_32 = &temp;
                break;

        case USBTEST_REQUEST_32:
                break;

        default:
                retval = -EOPNOTSUPP;
                goto free_mutex;
        }

        ktime_get_ts64(&start);

        retval = usbtest_do_ioctl(intf, param_32);
        if (retval)
                goto free_mutex;

        ktime_get_ts64(&end);

        duration = timespec64_sub(end, start);

        temp.duration_sec = duration.tv_sec;
        temp.duration_usec = duration.tv_nsec/NSEC_PER_USEC;

        switch (code) {
        case USBTEST_REQUEST_32:
                param_32->duration_sec = temp.duration_sec;
                param_32->duration_usec = temp.duration_usec;
                break;

        case USBTEST_REQUEST_64:
                param_64->duration_sec = temp.duration_sec;
                param_64->duration_usec = temp.duration_usec;
                break;
        }

free_mutex:
        mutex_unlock(&dev->lock);
        return retval;
}

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

static unsigned force_interrupt;
module_param(force_interrupt, uint, 0);
MODULE_PARM_DESC(force_interrupt, "0 = test default; else interrupt");

#ifdef  GENERIC
static unsigned short vendor;
module_param(vendor, ushort, 0);
MODULE_PARM_DESC(vendor, "vendor code (from usb-if)");

static unsigned short product;
module_param(product, ushort, 0);
MODULE_PARM_DESC(product, "product code (from vendor)");
#endif

static int
usbtest_probe(struct usb_interface *intf, const struct usb_device_id *id)
{
        struct usb_device       *udev;
        struct usbtest_dev      *dev;
        struct usbtest_info     *info;
        char                    *rtest, *wtest;
        char                    *irtest, *iwtest;
        char                    *intrtest, *intwtest;

        udev = interface_to_usbdev(intf);

#ifdef  GENERIC
        /* specify devices by module parameters? */
        if (id->match_flags == 0) {
                /* vendor match required, product match optional */
                if (!vendor || le16_to_cpu(udev->descriptor.idVendor) != (u16)vendor)
                        return -ENODEV;
                if (product && le16_to_cpu(udev->descriptor.idProduct) != (u16)product)
                        return -ENODEV;
                dev_info(&intf->dev, "matched module params, "
                                        "vend=0x%04x prod=0x%04x\n",
                                le16_to_cpu(udev->descriptor.idVendor),
                                le16_to_cpu(udev->descriptor.idProduct));
        }
#endif

        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
        if (!dev)
                return -ENOMEM;
        info = (struct usbtest_info *) id->driver_info;
        dev->info = info;
        mutex_init(&dev->lock);

        dev->intf = intf;

        /* cacheline-aligned scratch for i/o */
        dev->buf = kmalloc(TBUF_SIZE, GFP_KERNEL);
        if (dev->buf == NULL) {
                kfree(dev);
                return -ENOMEM;
        }

        /* NOTE this doesn't yet test the handful of difference that are
         * visible with high speed interrupts:  bigger maxpacket (1K) and
         * "high bandwidth" modes (up to 3 packets/uframe).
         */
        rtest = wtest = "";
        irtest = iwtest = "";
        intrtest = intwtest = "";
        if (force_interrupt || udev->speed == USB_SPEED_LOW) {
                if (info->ep_in) {
                        dev->in_pipe = usb_rcvintpipe(udev, info->ep_in);
                        rtest = " intr-in";
                }
                if (info->ep_out) {
                        dev->out_pipe = usb_sndintpipe(udev, info->ep_out);
                        wtest = " intr-out";
                }
        } else {
                if (override_alt >= 0 || info->autoconf) {
                        int status;

                        status = get_endpoints(dev, intf);
                        if (status < 0) {
                                WARNING(dev, "couldn't get endpoints, %d\n",
                                                status);
                                kfree(dev->buf);
                                kfree(dev);
                                return status;
                        }
                        /* may find bulk or ISO pipes */
                } else {
                        if (info->ep_in)
                                dev->in_pipe = usb_rcvbulkpipe(udev,
                                                        info->ep_in);
                        if (info->ep_out)
                                dev->out_pipe = usb_sndbulkpipe(udev,
                                                        info->ep_out);
                }
                if (dev->in_pipe)
                        rtest = " bulk-in";
                if (dev->out_pipe)
                        wtest = " bulk-out";
                if (dev->in_iso_pipe)
                        irtest = " iso-in";
                if (dev->out_iso_pipe)
                        iwtest = " iso-out";
                if (dev->in_int_pipe)
                        intrtest = " int-in";
                if (dev->out_int_pipe)
                        intwtest = " int-out";
        }

        usb_set_intfdata(intf, dev);
        dev_info(&intf->dev, "%s\n", info->name);
        dev_info(&intf->dev, "%s {control%s%s%s%s%s%s%s} tests%s\n",
                        usb_speed_string(udev->speed),
                        info->ctrl_out ? " in/out" : "",
                        rtest, wtest,
                        irtest, iwtest,
                        intrtest, intwtest,
                        info->alt >= 0 ? " (+alt)" : "");
        return 0;
}

static int usbtest_suspend(struct usb_interface *intf, pm_message_t message)
{
        return 0;
}

static int usbtest_resume(struct usb_interface *intf)
{
        return 0;
}


static void usbtest_disconnect(struct usb_interface *intf)
{
        struct usbtest_dev      *dev = usb_get_intfdata(intf);

        usb_set_intfdata(intf, NULL);
        dev_dbg(&intf->dev, "disconnect\n");
        kfree(dev);
}

/* Basic testing only needs a device that can source or sink bulk traffic.
 * Any device can test control transfers (default with GENERIC binding).
 *
 * Several entries work with the default EP0 implementation that's built
 * into EZ-USB chips.  There's a default vendor ID which can be overridden
 * by (very) small config EEPROMS, but otherwise all these devices act
 * identically until firmware is loaded:  only EP0 works.  It turns out
 * to be easy to make other endpoints work, without modifying that EP0
 * behavior.  For now, we expect that kind of firmware.
 */

/* an21xx or fx versions of ez-usb */
static struct usbtest_info ez1_info = {
        .name           = "EZ-USB device",
        .ep_in          = 2,
        .ep_out         = 2,
        .alt            = 1,
};

/* fx2 version of ez-usb */
static struct usbtest_info ez2_info = {
        .name           = "FX2 device",
        .ep_in          = 6,
        .ep_out         = 2,
        .alt            = 1,
};

/* ezusb family device with dedicated usb test firmware,
 */
static struct usbtest_info fw_info = {
        .name           = "usb test device",
        .ep_in          = 2,
        .ep_out         = 2,
        .alt            = 1,
        .autoconf       = 1,            /* iso and ctrl_out need autoconf */
        .ctrl_out       = 1,
        .iso            = 1,            /* iso_ep's are #8 in/out */
};

/* peripheral running Linux and 'zero.c' test firmware, or
 * its user-mode cousin. different versions of this use
 * different hardware with the same vendor/product codes.
 * host side MUST rely on the endpoint descriptors.
 */
static struct usbtest_info gz_info = {
        .name           = "Linux gadget zero",
        .autoconf       = 1,
        .ctrl_out       = 1,
        .iso            = 1,
        .intr           = 1,
        .alt            = 0,
};

static struct usbtest_info um_info = {
        .name           = "Linux user mode test driver",
        .autoconf       = 1,
        .alt            = -1,
};

static struct usbtest_info um2_info = {
        .name           = "Linux user mode ISO test driver",
        .autoconf       = 1,
        .iso            = 1,
        .alt            = -1,
};

#ifdef IBOT2
/* this is a nice source of high speed bulk data;
 * uses an FX2, with firmware provided in the device
 */
static struct usbtest_info ibot2_info = {
        .name           = "iBOT2 webcam",
        .ep_in          = 2,
        .alt            = -1,
};
#endif

#ifdef GENERIC
/* we can use any device to test control traffic */
static struct usbtest_info generic_info = {
        .name           = "Generic USB device",
        .alt            = -1,
};
#endif


static const struct usb_device_id id_table[] = {

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

        /* EZ-USB devices which download firmware to replace (or in our
         * case augment) the default device implementation.
         */

        /* generic EZ-USB FX controller */
        { USB_DEVICE(0x0547, 0x2235),
                .driver_info = (unsigned long) &ez1_info,
        },

        /* CY3671 development board with EZ-USB FX */
        { USB_DEVICE(0x0547, 0x0080),
                .driver_info = (unsigned long) &ez1_info,
        },

        /* generic EZ-USB FX2 controller (or development board) */
        { USB_DEVICE(0x04b4, 0x8613),
                .driver_info = (unsigned long) &ez2_info,
        },

        /* re-enumerated usb test device firmware */
        { USB_DEVICE(0xfff0, 0xfff0),
                .driver_info = (unsigned long) &fw_info,
        },

        /* "Gadget Zero" firmware runs under Linux */
        { USB_DEVICE(0x0525, 0xa4a0),
                .driver_info = (unsigned long) &gz_info,
        },

        /* so does a user-mode variant */
        { USB_DEVICE(0x0525, 0xa4a4),
                .driver_info = (unsigned long) &um_info,
        },

        /* ... and a user-mode variant that talks iso */
        { USB_DEVICE(0x0525, 0xa4a3),
                .driver_info = (unsigned long) &um2_info,
        },

#ifdef KEYSPAN_19Qi
        /* Keyspan 19qi uses an21xx (original EZ-USB) */
        /* this does not coexist with the real Keyspan 19qi driver! */
        { USB_DEVICE(0x06cd, 0x010b),
                .driver_info = (unsigned long) &ez1_info,
        },
#endif

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

#ifdef IBOT2
        /* iBOT2 makes a nice source of high speed bulk-in data */
        /* this does not coexist with a real iBOT2 driver! */
        { USB_DEVICE(0x0b62, 0x0059),
                .driver_info = (unsigned long) &ibot2_info,
        },
#endif

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

#ifdef GENERIC
        /* module params can specify devices to use for control tests */
        { .driver_info = (unsigned long) &generic_info, },
#endif

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

        { }
};
MODULE_DEVICE_TABLE(usb, id_table);

static struct usb_driver usbtest_driver = {
        .name =         "usbtest",
        .id_table =     id_table,
        .probe =        usbtest_probe,
        .unlocked_ioctl = usbtest_ioctl,
        .disconnect =   usbtest_disconnect,
        .suspend =      usbtest_suspend,
        .resume =       usbtest_resume,
};

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

static int __init usbtest_init(void)
{
#ifdef GENERIC
        if (vendor)
                pr_debug("params: vend=0x%04x prod=0x%04x\n", vendor, product);
#endif
        return usb_register(&usbtest_driver);
}
module_init(usbtest_init);

static void __exit usbtest_exit(void)
{
        usb_deregister(&usbtest_driver);
}
module_exit(usbtest_exit);

MODULE_DESCRIPTION("USB Core/HCD Testing Driver");
MODULE_LICENSE("GPL");