/*      $OpenBSD: umoscom.c,v 1.2 2006/10/26 06:02:43 jsg Exp $ */

/*
 * Copyright (c) 2006 Jonathan Gray <jsg@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/stdint.h>
#include <sys/stddef.h>
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/types.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bus.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/condvar.h>
#include <sys/sysctl.h>
#include <sys/sx.h>
#include <sys/unistd.h>
#include <sys/callout.h>
#include <sys/malloc.h>
#include <sys/priv.h>

#include <dev/usb/usb.h>
#include <dev/usb/usbdi.h>
#include <dev/usb/usbdi_util.h>
#include "usbdevs.h"

#define USB_DEBUG_VAR umoscom_debug
#include <dev/usb/usb_debug.h>
#include <dev/usb/usb_process.h>

#include <dev/usb/serial/usb_serial.h>

#ifdef USB_DEBUG
static int umoscom_debug = 0;

static SYSCTL_NODE(_hw_usb, OID_AUTO, umoscom, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "USB umoscom");
SYSCTL_INT(_hw_usb_umoscom, OID_AUTO, debug, CTLFLAG_RWTUN,
    &umoscom_debug, 0, "Debug level");
#endif

#define UMOSCOM_BUFSIZE        1024     /* bytes */

#define UMOSCOM_CONFIG_INDEX    0
#define UMOSCOM_IFACE_INDEX     0

/* interrupt packet */
#define UMOSCOM_IIR_RLS         0x06
#define UMOSCOM_IIR_RDA         0x04
#define UMOSCOM_IIR_CTI         0x0c
#define UMOSCOM_IIR_THR         0x02
#define UMOSCOM_IIR_MS          0x00

/* registers */
#define UMOSCOM_READ            0x0d
#define UMOSCOM_WRITE           0x0e
#define UMOSCOM_UART_REG        0x0300
#define UMOSCOM_VEND_REG        0x0000

#define UMOSCOM_TXBUF           0x00    /* Write */
#define UMOSCOM_RXBUF           0x00    /* Read */
#define UMOSCOM_INT             0x01
#define UMOSCOM_FIFO            0x02    /* Write */
#define UMOSCOM_ISR             0x02    /* Read */
#define UMOSCOM_LCR             0x03
#define UMOSCOM_MCR             0x04
#define UMOSCOM_LSR             0x05
#define UMOSCOM_MSR             0x06
#define UMOSCOM_SCRATCH         0x07
#define UMOSCOM_DIV_LO          0x08
#define UMOSCOM_DIV_HI          0x09
#define UMOSCOM_EFR             0x0a
#define UMOSCOM_XON1            0x0b
#define UMOSCOM_XON2            0x0c
#define UMOSCOM_XOFF1           0x0d
#define UMOSCOM_XOFF2           0x0e

#define UMOSCOM_BAUDLO          0x00
#define UMOSCOM_BAUDHI          0x01

#define UMOSCOM_INT_RXEN        0x01
#define UMOSCOM_INT_TXEN        0x02
#define UMOSCOM_INT_RSEN        0x04
#define UMOSCOM_INT_MDMEM       0x08
#define UMOSCOM_INT_SLEEP       0x10
#define UMOSCOM_INT_XOFF        0x20
#define UMOSCOM_INT_RTS         0x40

#define UMOSCOM_FIFO_EN         0x01
#define UMOSCOM_FIFO_RXCLR      0x02
#define UMOSCOM_FIFO_TXCLR      0x04
#define UMOSCOM_FIFO_DMA_BLK    0x08
#define UMOSCOM_FIFO_TXLVL_MASK 0x30
#define UMOSCOM_FIFO_TXLVL_8    0x00
#define UMOSCOM_FIFO_TXLVL_16   0x10
#define UMOSCOM_FIFO_TXLVL_32   0x20
#define UMOSCOM_FIFO_TXLVL_56   0x30
#define UMOSCOM_FIFO_RXLVL_MASK 0xc0
#define UMOSCOM_FIFO_RXLVL_8    0x00
#define UMOSCOM_FIFO_RXLVL_16   0x40
#define UMOSCOM_FIFO_RXLVL_56   0x80
#define UMOSCOM_FIFO_RXLVL_80   0xc0

#define UMOSCOM_ISR_MDM         0x00
#define UMOSCOM_ISR_NONE        0x01
#define UMOSCOM_ISR_TX          0x02
#define UMOSCOM_ISR_RX          0x04
#define UMOSCOM_ISR_LINE        0x06
#define UMOSCOM_ISR_RXTIMEOUT   0x0c
#define UMOSCOM_ISR_RX_XOFF     0x10
#define UMOSCOM_ISR_RTSCTS      0x20
#define UMOSCOM_ISR_FIFOEN      0xc0

#define UMOSCOM_LCR_DBITS(x)    ((x) - 5)
#define UMOSCOM_LCR_STOP_BITS_1 0x00
#define UMOSCOM_LCR_STOP_BITS_2 0x04    /* 2 if 6-8 bits/char or 1.5 if 5 */
#define UMOSCOM_LCR_PARITY_NONE 0x00
#define UMOSCOM_LCR_PARITY_ODD  0x08
#define UMOSCOM_LCR_PARITY_EVEN 0x18
#define UMOSCOM_LCR_BREAK       0x40
#define UMOSCOM_LCR_DIVLATCH_EN 0x80

#define UMOSCOM_MCR_DTR         0x01
#define UMOSCOM_MCR_RTS         0x02
#define UMOSCOM_MCR_LOOP        0x04
#define UMOSCOM_MCR_INTEN       0x08
#define UMOSCOM_MCR_LOOPBACK    0x10
#define UMOSCOM_MCR_XONANY      0x20
#define UMOSCOM_MCR_IRDA_EN     0x40
#define UMOSCOM_MCR_BAUD_DIV4   0x80

#define UMOSCOM_LSR_RXDATA      0x01
#define UMOSCOM_LSR_RXOVER      0x02
#define UMOSCOM_LSR_RXPAR_ERR   0x04
#define UMOSCOM_LSR_RXFRM_ERR   0x08
#define UMOSCOM_LSR_RXBREAK     0x10
#define UMOSCOM_LSR_TXEMPTY     0x20
#define UMOSCOM_LSR_TXALLEMPTY  0x40
#define UMOSCOM_LSR_TXFIFO_ERR  0x80

#define UMOSCOM_MSR_CTS_CHG     0x01
#define UMOSCOM_MSR_DSR_CHG     0x02
#define UMOSCOM_MSR_RI_CHG      0x04
#define UMOSCOM_MSR_CD_CHG      0x08
#define UMOSCOM_MSR_CTS         0x10
#define UMOSCOM_MSR_RTS         0x20
#define UMOSCOM_MSR_RI          0x40
#define UMOSCOM_MSR_CD          0x80

#define UMOSCOM_BAUD_REF        115200

enum {
        UMOSCOM_BULK_DT_WR,
        UMOSCOM_BULK_DT_RD,
        UMOSCOM_INTR_DT_RD,
        UMOSCOM_N_TRANSFER,
};

struct umoscom_softc {
        struct ucom_super_softc sc_super_ucom;
        struct ucom_softc sc_ucom;

        struct usb_xfer *sc_xfer[UMOSCOM_N_TRANSFER];
        struct usb_device *sc_udev;
        struct mtx sc_mtx;

        uint8_t sc_mcr;
        uint8_t sc_lcr;
};

/* prototypes */

static device_probe_t umoscom_probe;
static device_attach_t umoscom_attach;
static device_detach_t umoscom_detach;
static void umoscom_free_softc(struct umoscom_softc *);

static usb_callback_t umoscom_write_callback;
static usb_callback_t umoscom_read_callback;
static usb_callback_t umoscom_intr_callback;

static void     umoscom_free(struct ucom_softc *);
static void     umoscom_cfg_open(struct ucom_softc *);
static void     umoscom_cfg_close(struct ucom_softc *);
static void     umoscom_cfg_set_break(struct ucom_softc *, uint8_t);
static void     umoscom_cfg_set_dtr(struct ucom_softc *, uint8_t);
static void     umoscom_cfg_set_rts(struct ucom_softc *, uint8_t);
static int      umoscom_pre_param(struct ucom_softc *, struct termios *);
static void     umoscom_cfg_param(struct ucom_softc *, struct termios *);
static void     umoscom_cfg_get_status(struct ucom_softc *, uint8_t *,
                    uint8_t *);
static void     umoscom_cfg_write(struct umoscom_softc *, uint16_t, uint16_t);
static uint8_t  umoscom_cfg_read(struct umoscom_softc *, uint16_t);
static void     umoscom_start_read(struct ucom_softc *);
static void     umoscom_stop_read(struct ucom_softc *);
static void     umoscom_start_write(struct ucom_softc *);
static void     umoscom_stop_write(struct ucom_softc *);
static void     umoscom_poll(struct ucom_softc *ucom);

static const struct usb_config umoscom_config_data[UMOSCOM_N_TRANSFER] = {
        [UMOSCOM_BULK_DT_WR] = {
                .type = UE_BULK,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_OUT,
                .bufsize = UMOSCOM_BUFSIZE,
                .flags = {.pipe_bof = 1,.force_short_xfer = 1,},
                .callback = &umoscom_write_callback,
        },

        [UMOSCOM_BULK_DT_RD] = {
                .type = UE_BULK,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_IN,
                .bufsize = UMOSCOM_BUFSIZE,
                .flags = {.pipe_bof = 1,.short_xfer_ok = 1,},
                .callback = &umoscom_read_callback,
        },

        [UMOSCOM_INTR_DT_RD] = {
                .type = UE_INTERRUPT,
                .endpoint = UE_ADDR_ANY,
                .direction = UE_DIR_IN,
                .flags = {.pipe_bof = 1,.short_xfer_ok = 1,},
                .bufsize = 0,   /* use wMaxPacketSize */
                .callback = &umoscom_intr_callback,
        },
};

static const struct ucom_callback umoscom_callback = {
        /* configuration callbacks */
        .ucom_cfg_get_status = &umoscom_cfg_get_status,
        .ucom_cfg_set_dtr = &umoscom_cfg_set_dtr,
        .ucom_cfg_set_rts = &umoscom_cfg_set_rts,
        .ucom_cfg_set_break = &umoscom_cfg_set_break,
        .ucom_cfg_param = &umoscom_cfg_param,
        .ucom_cfg_open = &umoscom_cfg_open,
        .ucom_cfg_close = &umoscom_cfg_close,

        /* other callbacks */
        .ucom_pre_param = &umoscom_pre_param,
        .ucom_start_read = &umoscom_start_read,
        .ucom_stop_read = &umoscom_stop_read,
        .ucom_start_write = &umoscom_start_write,
        .ucom_stop_write = &umoscom_stop_write,
        .ucom_poll = &umoscom_poll,
        .ucom_free = &umoscom_free,
};

static device_method_t umoscom_methods[] = {
        DEVMETHOD(device_probe, umoscom_probe),
        DEVMETHOD(device_attach, umoscom_attach),
        DEVMETHOD(device_detach, umoscom_detach),
        DEVMETHOD_END
};

static driver_t umoscom_driver = {
        .name = "umoscom",
        .methods = umoscom_methods,
        .size = sizeof(struct umoscom_softc),
};

static const STRUCT_USB_HOST_ID umoscom_devs[] = {
        {USB_VPI(USB_VENDOR_MOSCHIP, USB_PRODUCT_MOSCHIP_MCS7703, 0)}
};

DRIVER_MODULE(umoscom, uhub, umoscom_driver, NULL, NULL);
MODULE_DEPEND(umoscom, ucom, 1, 1, 1);
MODULE_DEPEND(umoscom, usb, 1, 1, 1);
MODULE_VERSION(umoscom, 1);
USB_PNP_HOST_INFO(umoscom_devs);

static int
umoscom_probe(device_t dev)
{
        struct usb_attach_arg *uaa = device_get_ivars(dev);

        if (uaa->usb_mode != USB_MODE_HOST) {
                return (ENXIO);
        }
        if (uaa->info.bConfigIndex != UMOSCOM_CONFIG_INDEX) {
                return (ENXIO);
        }
        if (uaa->info.bIfaceIndex != UMOSCOM_IFACE_INDEX) {
                return (ENXIO);
        }
        return (usbd_lookup_id_by_uaa(umoscom_devs, sizeof(umoscom_devs), uaa));
}

static int
umoscom_attach(device_t dev)
{
        struct usb_attach_arg *uaa = device_get_ivars(dev);
        struct umoscom_softc *sc = device_get_softc(dev);
        int error;
        uint8_t iface_index;

        sc->sc_udev = uaa->device;
        sc->sc_mcr = 0x08;              /* enable interrupts */

        /* XXX the device doesn't provide any ID string, so set a static one */
        device_set_desc(dev, "MOSCHIP USB Serial Port Adapter");
        device_printf(dev, "<MOSCHIP USB Serial Port Adapter>\n");

        mtx_init(&sc->sc_mtx, "umoscom", NULL, MTX_DEF);
        ucom_ref(&sc->sc_super_ucom);

        iface_index = UMOSCOM_IFACE_INDEX;
        error = usbd_transfer_setup(uaa->device, &iface_index,
            sc->sc_xfer, umoscom_config_data,
            UMOSCOM_N_TRANSFER, sc, &sc->sc_mtx);

        if (error) {
                goto detach;
        }
        /* clear stall at first run */
        mtx_lock(&sc->sc_mtx);
        usbd_xfer_set_stall(sc->sc_xfer[UMOSCOM_BULK_DT_WR]);
        usbd_xfer_set_stall(sc->sc_xfer[UMOSCOM_BULK_DT_RD]);
        mtx_unlock(&sc->sc_mtx);

        error = ucom_attach(&sc->sc_super_ucom, &sc->sc_ucom, 1, sc,
            &umoscom_callback, &sc->sc_mtx);
        if (error) {
                goto detach;
        }
        ucom_set_pnpinfo_usb(&sc->sc_super_ucom, dev);

        return (0);

detach:
        device_printf(dev, "attach error: %s\n", usbd_errstr(error));
        umoscom_detach(dev);
        return (ENXIO);
}

static int
umoscom_detach(device_t dev)
{
        struct umoscom_softc *sc = device_get_softc(dev);

        ucom_detach(&sc->sc_super_ucom, &sc->sc_ucom);
        usbd_transfer_unsetup(sc->sc_xfer, UMOSCOM_N_TRANSFER);

        device_claim_softc(dev);

        umoscom_free_softc(sc);

        return (0);
}

UCOM_UNLOAD_DRAIN(umoscom);

static void
umoscom_free_softc(struct umoscom_softc *sc)
{
        if (ucom_unref(&sc->sc_super_ucom)) {
                mtx_destroy(&sc->sc_mtx);
                device_free_softc(sc);
        }
}

static void
umoscom_free(struct ucom_softc *ucom)
{
        umoscom_free_softc(ucom->sc_parent);
}

static void
umoscom_cfg_open(struct ucom_softc *ucom)
{
        struct umoscom_softc *sc = ucom->sc_parent;

        DPRINTF("\n");

        /* Purge FIFOs or odd things happen */
        umoscom_cfg_write(sc, UMOSCOM_FIFO, 0x00 | UMOSCOM_UART_REG);

        /* Enable FIFO */
        umoscom_cfg_write(sc, UMOSCOM_FIFO, UMOSCOM_FIFO_EN |
            UMOSCOM_FIFO_RXCLR | UMOSCOM_FIFO_TXCLR |
            UMOSCOM_FIFO_DMA_BLK | UMOSCOM_FIFO_RXLVL_MASK |
            UMOSCOM_UART_REG);

        /* Enable Interrupt Registers */
        umoscom_cfg_write(sc, UMOSCOM_INT, 0x0C | UMOSCOM_UART_REG);

        /* Magic */
        umoscom_cfg_write(sc, 0x01, 0x08);

        /* Magic */
        umoscom_cfg_write(sc, 0x00, 0x02);
}

static void
umoscom_cfg_close(struct ucom_softc *ucom)
{
        return;
}

static void
umoscom_cfg_set_break(struct ucom_softc *ucom, uint8_t onoff)
{
        struct umoscom_softc *sc = ucom->sc_parent;
        uint16_t val;

        val = sc->sc_lcr;
        if (onoff)
                val |= UMOSCOM_LCR_BREAK;

        umoscom_cfg_write(sc, UMOSCOM_LCR, val | UMOSCOM_UART_REG);
}

static void
umoscom_cfg_set_dtr(struct ucom_softc *ucom, uint8_t onoff)
{
        struct umoscom_softc *sc = ucom->sc_parent;

        if (onoff)
                sc->sc_mcr |= UMOSCOM_MCR_DTR;
        else
                sc->sc_mcr &= ~UMOSCOM_MCR_DTR;

        umoscom_cfg_write(sc, UMOSCOM_MCR, sc->sc_mcr | UMOSCOM_UART_REG);
}

static void
umoscom_cfg_set_rts(struct ucom_softc *ucom, uint8_t onoff)
{
        struct umoscom_softc *sc = ucom->sc_parent;

        if (onoff)
                sc->sc_mcr |= UMOSCOM_MCR_RTS;
        else
                sc->sc_mcr &= ~UMOSCOM_MCR_RTS;

        umoscom_cfg_write(sc, UMOSCOM_MCR, sc->sc_mcr | UMOSCOM_UART_REG);
}

static int
umoscom_pre_param(struct ucom_softc *ucom, struct termios *t)
{
        if ((t->c_ospeed <= 1) || (t->c_ospeed > 115200))
                return (EINVAL);

        return (0);
}

static void
umoscom_cfg_param(struct ucom_softc *ucom, struct termios *t)
{
        struct umoscom_softc *sc = ucom->sc_parent;
        uint16_t data;

        DPRINTF("speed=%d\n", t->c_ospeed);

        data = ((uint32_t)UMOSCOM_BAUD_REF) / ((uint32_t)t->c_ospeed);

        if (data == 0) {
                DPRINTF("invalid baud rate!\n");
                return;
        }
        umoscom_cfg_write(sc, UMOSCOM_LCR,
            UMOSCOM_LCR_DIVLATCH_EN | UMOSCOM_UART_REG);

        umoscom_cfg_write(sc, UMOSCOM_BAUDLO,
            (data & 0xFF) | UMOSCOM_UART_REG);

        umoscom_cfg_write(sc, UMOSCOM_BAUDHI,
            ((data >> 8) & 0xFF) | UMOSCOM_UART_REG);

        if (t->c_cflag & CSTOPB)
                data = UMOSCOM_LCR_STOP_BITS_2;
        else
                data = UMOSCOM_LCR_STOP_BITS_1;

        if (t->c_cflag & PARENB) {
                if (t->c_cflag & PARODD)
                        data |= UMOSCOM_LCR_PARITY_ODD;
                else
                        data |= UMOSCOM_LCR_PARITY_EVEN;
        } else
                data |= UMOSCOM_LCR_PARITY_NONE;

        switch (t->c_cflag & CSIZE) {
        case CS5:
                data |= UMOSCOM_LCR_DBITS(5);
                break;
        case CS6:
                data |= UMOSCOM_LCR_DBITS(6);
                break;
        case CS7:
                data |= UMOSCOM_LCR_DBITS(7);
                break;
        case CS8:
                data |= UMOSCOM_LCR_DBITS(8);
                break;
        }

        sc->sc_lcr = data;
        umoscom_cfg_write(sc, UMOSCOM_LCR, data | UMOSCOM_UART_REG);
}

static void
umoscom_cfg_get_status(struct ucom_softc *ucom, uint8_t *p_lsr, uint8_t *p_msr)
{
        struct umoscom_softc *sc = ucom->sc_parent;
        uint8_t msr;

        DPRINTFN(5, "\n");

        /*
         * Read status registers.  MSR bits need translation from ns16550 to
         * SER_* values.  LSR bits are ns16550 in hardware and ucom.
         */

        *p_lsr = umoscom_cfg_read(sc, UMOSCOM_LSR);
        msr = umoscom_cfg_read(sc, UMOSCOM_MSR);

        /* translate bits */

        if (msr & UMOSCOM_MSR_CTS)
                *p_msr |= SER_CTS;

        if (msr & UMOSCOM_MSR_CD)
                *p_msr |= SER_DCD;

        if (msr & UMOSCOM_MSR_RI)
                *p_msr |= SER_RI;

        if (msr & UMOSCOM_MSR_RTS)
                *p_msr |= SER_DSR;
}

static void
umoscom_cfg_write(struct umoscom_softc *sc, uint16_t reg, uint16_t val)
{
        struct usb_device_request req;

        req.bmRequestType = UT_WRITE_VENDOR_DEVICE;
        req.bRequest = UMOSCOM_WRITE;
        USETW(req.wValue, val);
        USETW(req.wIndex, reg);
        USETW(req.wLength, 0);

        ucom_cfg_do_request(sc->sc_udev, &sc->sc_ucom,
            &req, NULL, 0, 1000);
}

static uint8_t
umoscom_cfg_read(struct umoscom_softc *sc, uint16_t reg)
{
        struct usb_device_request req;
        uint8_t val;

        req.bmRequestType = UT_READ_VENDOR_DEVICE;
        req.bRequest = UMOSCOM_READ;
        USETW(req.wValue, 0);
        USETW(req.wIndex, reg);
        USETW(req.wLength, 1);

        ucom_cfg_do_request(sc->sc_udev, &sc->sc_ucom, 
            &req, &val, 0, 1000);

        DPRINTF("reg=0x%04x, val=0x%02x\n", reg, val);

        return (val);
}

static void
umoscom_start_read(struct ucom_softc *ucom)
{
        struct umoscom_softc *sc = ucom->sc_parent;

#if 0
        /* start interrupt endpoint */
        usbd_transfer_start(sc->sc_xfer[UMOSCOM_INTR_DT_RD]);
#endif
        /* start read endpoint */
        usbd_transfer_start(sc->sc_xfer[UMOSCOM_BULK_DT_RD]);
}

static void
umoscom_stop_read(struct ucom_softc *ucom)
{
        struct umoscom_softc *sc = ucom->sc_parent;

        /* stop interrupt transfer */
        usbd_transfer_stop(sc->sc_xfer[UMOSCOM_INTR_DT_RD]);

        /* stop read endpoint */
        usbd_transfer_stop(sc->sc_xfer[UMOSCOM_BULK_DT_RD]);
}

static void
umoscom_start_write(struct ucom_softc *ucom)
{
        struct umoscom_softc *sc = ucom->sc_parent;

        usbd_transfer_start(sc->sc_xfer[UMOSCOM_BULK_DT_WR]);
}

static void
umoscom_stop_write(struct ucom_softc *ucom)
{
        struct umoscom_softc *sc = ucom->sc_parent;

        usbd_transfer_stop(sc->sc_xfer[UMOSCOM_BULK_DT_WR]);
}

static void
umoscom_write_callback(struct usb_xfer *xfer, usb_error_t error)
{
        struct umoscom_softc *sc = usbd_xfer_softc(xfer);
        struct usb_page_cache *pc;
        uint32_t actlen;

        switch (USB_GET_STATE(xfer)) {
        case USB_ST_SETUP:
        case USB_ST_TRANSFERRED:
tr_setup:
                DPRINTF("\n");

                pc = usbd_xfer_get_frame(xfer, 0);
                if (ucom_get_data(&sc->sc_ucom, pc, 0,
                    UMOSCOM_BUFSIZE, &actlen)) {
                        usbd_xfer_set_frame_len(xfer, 0, actlen);
                        usbd_transfer_submit(xfer);
                }
                return;

        default:                        /* Error */
                if (error != USB_ERR_CANCELLED) {
                        DPRINTFN(0, "transfer failed\n");
                        /* try to clear stall first */
                        usbd_xfer_set_stall(xfer);
                        goto tr_setup;
                }
                return;
        }
}

static void
umoscom_read_callback(struct usb_xfer *xfer, usb_error_t error)
{
        struct umoscom_softc *sc = usbd_xfer_softc(xfer);
        struct usb_page_cache *pc;
        int actlen;

        usbd_xfer_status(xfer, &actlen, NULL, NULL, NULL);

        switch (USB_GET_STATE(xfer)) {
        case USB_ST_TRANSFERRED:
                DPRINTF("got %d bytes\n", actlen);
                pc = usbd_xfer_get_frame(xfer, 0);
                ucom_put_data(&sc->sc_ucom, pc, 0, actlen);

        case USB_ST_SETUP:
tr_setup:
                DPRINTF("\n");

                usbd_xfer_set_frame_len(xfer, 0, usbd_xfer_max_len(xfer));
                usbd_transfer_submit(xfer);
                return;

        default:                        /* Error */
                if (error != USB_ERR_CANCELLED) {
                        DPRINTFN(0, "transfer failed\n");
                        /* try to clear stall first */
                        usbd_xfer_set_stall(xfer);
                        goto tr_setup;
                }
                return;
        }
}

static void
umoscom_intr_callback(struct usb_xfer *xfer, usb_error_t error)
{
        struct umoscom_softc *sc = usbd_xfer_softc(xfer);
        int actlen;

        usbd_xfer_status(xfer, &actlen, NULL, NULL, NULL);

        switch (USB_GET_STATE(xfer)) {
        case USB_ST_TRANSFERRED:
                if (actlen < 2) {
                        DPRINTF("too short message\n");
                        goto tr_setup;
                }
                ucom_status_change(&sc->sc_ucom);

        case USB_ST_SETUP:
tr_setup:
                usbd_xfer_set_frame_len(xfer, 0, usbd_xfer_max_len(xfer));
                usbd_transfer_submit(xfer);
                return;

        default:                        /* Error */
                if (error != USB_ERR_CANCELLED) {
                        DPRINTFN(0, "transfer failed\n");
                        /* try to clear stall first */
                        usbd_xfer_set_stall(xfer);
                        goto tr_setup;
                }
                return;
        }
}

static void
umoscom_poll(struct ucom_softc *ucom)
{
        struct umoscom_softc *sc = ucom->sc_parent;
        usbd_transfer_poll(sc->sc_xfer, UMOSCOM_N_TRANSFER);
}