/* $NetBSD: umcs.c,v 1.22 2024/02/09 22:08:37 andvar Exp $ */
/* $FreeBSD: head/sys/dev/usb/serial/umcs.c 260559 2014-01-12 11:44:28Z hselasky $ */

/*-
 * Copyright (c) 2010 Lev Serebryakov <lev@FreeBSD.org>.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * This driver supports several multiport USB-to-RS232 serial adapters driven
 * by MosChip mos7820 and mos7840, bridge chips.
 * The adapters are sold under many different brand names.
 *
 * Datasheets are available at MosChip www site at
 * http://www.moschip.com.  The datasheets don't contain full
 * programming information for the chip.
 *
 * It is normal to have only two enabled ports in devices, based on
 * quad-port mos7840.
 *
 */
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: umcs.c,v 1.22 2024/02/09 22:08:37 andvar Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/atomic.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/tty.h>
#include <sys/device.h>
#include <sys/kmem.h>

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

#include <dev/usb/usbdevs.h>
#include <dev/usb/ucomvar.h>

#include "umcs.h"

#if 0
#define DPRINTF(ARG)    printf ARG
#else
#define DPRINTF(ARG)
#endif

/*
 * Two-port devices (both with 7820 chip and 7840 chip configured as two-port)
 * have ports 0 and 2, with ports 1 and 3 omitted.
 * So, PHYSICAL port numbers on two-port device will be 0 and 2.
 *
 * We use an array of the following struct, indexed by ucom port index,
 * and include the physical port number in it.
 */
struct umcs7840_softc_oneport {
        device_t sc_port_ucom;          /* ucom subdevice */
        unsigned int sc_port_phys;      /* physical port number */
        uint8_t sc_port_lcr;            /* local line control register */
        uint8_t sc_port_mcr;            /* local modem control register */
};

struct umcs7840_softc {
        device_t sc_dev;                /* ourself */
        enum {
                UMCS_INIT_NONE,
                UMCS_INIT_INITED
        } sc_init_state;
        struct usbd_interface *sc_iface; /* the usb interface */
        struct usbd_device *sc_udev;    /* the usb device */
        struct usbd_pipe *sc_intr_pipe; /* interrupt pipe */
        uint8_t *sc_intr_buf;           /* buffer for interrupt xfer */
        unsigned int sc_intr_buflen;    /* size of buffer */
        struct usb_task sc_change_task; /* async status changes */
        volatile uint32_t sc_change_mask;       /* mask of port changes */
        struct umcs7840_softc_oneport sc_ports[UMCS7840_MAX_PORTS];
                                        /* data for each port */
        uint8_t sc_numports;            /* number of ports (subunits) */
        bool sc_init_done;              /* special one time init in open */
        bool sc_dying;                  /* we have been deactivated */
};

static int umcs7840_get_reg(struct umcs7840_softc *, uint8_t, uint8_t *);
static int umcs7840_set_reg(struct umcs7840_softc *, uint8_t, uint8_t);
static int umcs7840_get_UART_reg(struct umcs7840_softc *, uint8_t, uint8_t, uint8_t *);
static int umcs7840_set_UART_reg(struct umcs7840_softc *, uint8_t, uint8_t, uint8_t );
static int umcs7840_calc_baudrate(uint32_t, uint16_t *, uint8_t *);
static void umcs7840_dtr(struct umcs7840_softc *, int, bool);
static void umcs7840_rts(struct umcs7840_softc *, int, bool);
static void umcs7840_break(struct umcs7840_softc *, int, bool );

static int umcs7840_match(device_t, cfdata_t, void *);
static void umcs7840_attach(device_t, device_t, void *);
static int umcs7840_detach(device_t, int);
static void umcs7840_intr(struct usbd_xfer *, void *, usbd_status);
static void umcs7840_change_task(void *arg);
static void umcs7840_childdet(device_t, device_t);

static void umcs7840_get_status(void *, int, u_char *, u_char *);
static void umcs7840_set(void *, int, int, int);
static int umcs7840_param(void *, int, struct termios *);
static int umcs7840_port_open(void *, int);
static void umcs7840_port_close(void *, int);

static const struct ucom_methods umcs7840_methods = {
        .ucom_get_status = umcs7840_get_status,
        .ucom_set = umcs7840_set,
        .ucom_param = umcs7840_param,
        .ucom_open = umcs7840_port_open,
        .ucom_close = umcs7840_port_close,
};

static const struct usb_devno umcs7840_devs[] = {
        { USB_VENDOR_MOSCHIP,           USB_PRODUCT_MOSCHIP_MCS7703 },
        { USB_VENDOR_MOSCHIP,           USB_PRODUCT_MOSCHIP_MCS7810 },
        { USB_VENDOR_MOSCHIP,           USB_PRODUCT_MOSCHIP_MCS7820 },
        { USB_VENDOR_MOSCHIP,           USB_PRODUCT_MOSCHIP_MCS7840 },
        { USB_VENDOR_ATEN,              USB_PRODUCT_ATEN_UC2324 }
};
#define umcs7840_lookup(v, p) usb_lookup(umcs7840_devs, v, p)

CFATTACH_DECL2_NEW(umcs, sizeof(struct umcs7840_softc), umcs7840_match,
    umcs7840_attach, umcs7840_detach, NULL, NULL,
    umcs7840_childdet);

static inline int
umcs7840_reg_sp(int phyport)
{
        KASSERT(phyport >= 0 && phyport < 4);
        switch (phyport) {
        default:
        case 0: return MCS7840_DEV_REG_SP1;
        case 1: return MCS7840_DEV_REG_SP2;
        case 2: return MCS7840_DEV_REG_SP3;
        case 3: return MCS7840_DEV_REG_SP4;
        }
}

static inline int
umcs7840_reg_ctrl(int phyport)
{
        KASSERT(phyport >= 0 && phyport < 4);
        switch (phyport) {
        default:
        case 0: return MCS7840_DEV_REG_CONTROL1;
        case 1: return MCS7840_DEV_REG_CONTROL2;
        case 2: return MCS7840_DEV_REG_CONTROL3;
        case 3: return MCS7840_DEV_REG_CONTROL4;
        }
}

static int
umcs7840_match(device_t dev, cfdata_t match, void *aux)
{
        struct usb_attach_arg *uaa = aux;

        return umcs7840_lookup(uaa->uaa_vendor, uaa->uaa_product) != NULL ?
                UMATCH_VENDOR_PRODUCT : UMATCH_NONE;
}

static void
umcs7840_attach(device_t parent, device_t self, void *aux)
{
        struct umcs7840_softc *sc = device_private(self);
        struct usb_attach_arg *uaa = aux;
        struct usbd_device *dev = uaa->uaa_device;
        usb_interface_descriptor_t *id;
        usb_endpoint_descriptor_t *ed;
        char *devinfop;
        struct ucom_attach_args ucaa;
        int error, i, intr_addr;
        uint8_t data;

        sc->sc_dev = self;
        sc->sc_udev = uaa->uaa_device;
        sc->sc_dying = false;
        sc->sc_init_state = UMCS_INIT_NONE;

        if (usbd_set_config_index(sc->sc_udev, MCS7840_CONFIG_INDEX, 1) != 0) {
                aprint_error(": could not set configuration no\n");
                sc->sc_dying = true;
                return;
        }

        /* get the first interface handle */
        error = usbd_device2interface_handle(sc->sc_udev, MCS7840_IFACE_INDEX,
            &sc->sc_iface);
        if (error != 0) {
                aprint_error(": could not get interface handle\n");
                sc->sc_dying = true;
                return;
        }

        /*
         * Get number of ports
         * Documentation (full datasheet) says, that number of ports is
         * set as MCS7840_DEV_MODE_SELECT24S bit in MODE R/Only
         * register. But vendor driver uses these undocumented
         * register & bit.
         *
         * Experiments show, that MODE register can have `0'
         * (4 ports) bit on 2-port device, so use vendor driver's way.
         *
         * Also, see notes in header file for these constants.
         */
        error = umcs7840_get_reg(sc, MCS7840_DEV_REG_GPIO, &data);
        if (error == 0 && (data & MCS7840_DEV_GPIO_4PORTS) != 0) {
                sc->sc_numports = 4;
                /* physical port no are : 0, 1, 2, 3 */
        } else {
                if (uaa->uaa_product == USB_PRODUCT_MOSCHIP_MCS7810)
                        sc->sc_numports = 1;
                else {
                        sc->sc_numports = 2;
                        /* physical port no are : 0 and 2 */
                }
        }
        devinfop = usbd_devinfo_alloc(dev, 0);
        aprint_normal(": %s\n", devinfop);
        usbd_devinfo_free(devinfop);
        aprint_verbose_dev(self, "found %d active ports\n", sc->sc_numports);

        if (!umcs7840_get_reg(sc, MCS7840_DEV_REG_MODE, &data)) {
                aprint_verbose_dev(self, "On-die configuration: RST: active %s, "
                    "HRD: %s, PLL: %s, POR: %s, Ports: %s, EEPROM write %s, "
                    "IrDA is %savailable\n",
                    (data & MCS7840_DEV_MODE_RESET) ? "low" : "high",
                    (data & MCS7840_DEV_MODE_SER_PRSNT) ? "yes" : "no",
                    (data & MCS7840_DEV_MODE_PLLBYPASS) ? "bypassed" : "avail",
                    (data & MCS7840_DEV_MODE_PORBYPASS) ? "bypassed" : "avail",
                    (data & MCS7840_DEV_MODE_SELECT24S) ? "2" : "4",
                    (data & MCS7840_DEV_MODE_EEPROMWR) ? "enabled" : "disabled",
                    (data & MCS7840_DEV_MODE_IRDA) ? "" : "not ");
        }

        /*
         * Set up the interrupt pipe
         */
        id = usbd_get_interface_descriptor(sc->sc_iface);
        intr_addr = -1;
        for (i = 0 ; i < id->bNumEndpoints ; i++) {
                ed = usbd_interface2endpoint_descriptor(sc->sc_iface, i);
                if (ed == NULL) continue;
                if (UE_GET_DIR(ed->bEndpointAddress) != UE_DIR_IN
                    || UE_GET_XFERTYPE(ed->bmAttributes) != UE_INTERRUPT)
                        continue;
                sc->sc_intr_buflen = UGETW(ed->wMaxPacketSize);
                intr_addr = ed->bEndpointAddress;
                break;
        }
        if (intr_addr < 0) {
                aprint_error_dev(self, "interrupt pipe not found\n");
                sc->sc_dying = true;
                return;
        }
        if (sc->sc_intr_buflen == 0) {
                aprint_error_dev(self, "invalid interrupt endpoint"
                    " (addr %d)\n", intr_addr);
                sc->sc_dying = true;
                return;
        }
        sc->sc_intr_buf = kmem_alloc(sc->sc_intr_buflen, KM_SLEEP);

        error = usbd_open_pipe_intr(sc->sc_iface, intr_addr,
                    USBD_SHORT_XFER_OK, &sc->sc_intr_pipe, sc, sc->sc_intr_buf,
                    sc->sc_intr_buflen, umcs7840_intr, 100);
        if (error) {
                aprint_error_dev(self, "cannot open interrupt pipe "
                    "(addr %d): error %d\n", intr_addr, error);
                sc->sc_dying = true;
                return;
        }

        usb_init_task(&sc->sc_change_task, umcs7840_change_task, sc,
            USB_TASKQ_MPSAFE);

        usbd_add_drv_event(USB_EVENT_DRIVER_ATTACH, sc->sc_udev, sc->sc_dev);

        sc->sc_init_state = UMCS_INIT_INITED;

        memset(&ucaa, 0, sizeof(ucaa));
        ucaa.ucaa_ibufsize = 256;
        ucaa.ucaa_obufsize = 256;
        ucaa.ucaa_ibufsizepad = 256;
        ucaa.ucaa_opkthdrlen = 0;
        ucaa.ucaa_device = sc->sc_udev;
        ucaa.ucaa_iface = sc->sc_iface;
        ucaa.ucaa_methods = &umcs7840_methods;
        ucaa.ucaa_arg = sc;

        for (i = 0; i < sc->sc_numports; i++) {
                ucaa.ucaa_bulkin = ucaa.ucaa_bulkout = -1;

                /*
                 * On four port cards, endpoints are 0/1 for first,
                 * 2/3 for second, ...
                 * On two port cards, they are 0/1 for first, 4/5 for second.
                 * On single port, just 0/1 will be used.
                 */
                int phyport = i * (sc->sc_numports == 2 ? 2 : 1);

                ed = usbd_interface2endpoint_descriptor(sc->sc_iface,
                        phyport*2);
                if (ed == NULL) {
                        aprint_error_dev(self,
                            "no bulk in endpoint found for %d\n", i);
                        sc->sc_dying = true;
                        return;
                }
                ucaa.ucaa_bulkin = ed->bEndpointAddress;

                ed = usbd_interface2endpoint_descriptor(sc->sc_iface,
                        phyport*2 + 1);
                if (ed == NULL) {
                        aprint_error_dev(self,
                            "no bulk out endpoint found for %d\n", i);
                        return;
                }
                ucaa.ucaa_bulkout = ed->bEndpointAddress;
                ucaa.ucaa_portno = i;
                DPRINTF(("port %d physical port %d bulk-in %d bulk-out %d\n",
                    i, phyport, ucaa.ucaa_bulkin, ucaa.ucaa_bulkout));

                sc->sc_ports[i].sc_port_phys = phyport;
                sc->sc_ports[i].sc_port_ucom =
                    config_found(self, &ucaa, ucomprint,
                                 CFARGS(.submatch = ucomsubmatch));
        }
}

static int
umcs7840_get_reg(struct umcs7840_softc *sc, uint8_t reg, uint8_t *data)
{
        usb_device_request_t req;
        int err;

        req.bmRequestType = UT_READ_VENDOR_DEVICE;
        req.bRequest = MCS7840_RDREQ;
        USETW(req.wValue, 0);
        USETW(req.wIndex, reg);
        USETW(req.wLength, UMCS7840_READ_LENGTH);

        err = usbd_do_request(sc->sc_udev, &req, data);
        if (err)
                aprint_normal_dev(sc->sc_dev,
                    "Reading register %d failed: %s\n", reg, usbd_errstr(err));
        return err;
}

static int
umcs7840_set_reg(struct umcs7840_softc *sc, uint8_t reg, uint8_t data)
{
        usb_device_request_t req;
        int err;

        req.bmRequestType = UT_WRITE_VENDOR_DEVICE;
        req.bRequest = MCS7840_WRREQ;
        USETW(req.wValue, data);
        USETW(req.wIndex, reg);
        USETW(req.wLength, 0);

        err = usbd_do_request(sc->sc_udev, &req, 0);
        if (err)
                aprint_normal_dev(sc->sc_dev, "Writing register %d failed: %s\n", reg, usbd_errstr(err));

        return err;
}

static int
umcs7840_get_UART_reg(struct umcs7840_softc *sc, uint8_t portno,
        uint8_t reg, uint8_t *data)
{
        usb_device_request_t req;
        uint16_t wVal;
        int err;

        /* portno is port number */
        wVal = ((uint16_t)(portno + 1)) << 8;

        req.bmRequestType = UT_READ_VENDOR_DEVICE;
        req.bRequest = MCS7840_RDREQ;
        USETW(req.wValue, wVal);
        USETW(req.wIndex, reg);
        USETW(req.wLength, UMCS7840_READ_LENGTH);

        err = usbd_do_request(sc->sc_udev, &req, data);
        if (err)
                aprint_normal_dev(sc->sc_dev, "Reading UART %d register %d failed: %s\n", portno, reg, usbd_errstr(err));
        return err;
}

static int
umcs7840_set_UART_reg(struct umcs7840_softc *sc, uint8_t portno, uint8_t reg, uint8_t data)
{
        usb_device_request_t req;
        int err;
        uint16_t wVal;

        /* portno is the physical port number */
        wVal = ((uint16_t)(portno + 1)) << 8 | data;

        req.bmRequestType = UT_WRITE_VENDOR_DEVICE;
        req.bRequest = MCS7840_WRREQ;
        USETW(req.wValue, wVal);
        USETW(req.wIndex, reg);
        USETW(req.wLength, 0);

        err = usbd_do_request(sc->sc_udev, &req, NULL);
        if (err)
                aprint_error_dev(sc->sc_dev,
                    "Writing UART %d register %d failed: %s\n",
                    portno, reg, usbd_errstr(err));
        return err;
}

static int
umcs7840_set_baudrate(struct umcs7840_softc *sc, uint8_t portno,
        uint32_t rate)
{
        int err;
        uint16_t divisor;
        uint8_t clk;
        uint8_t data;
        uint8_t physport = sc->sc_ports[portno].sc_port_phys;
        int spreg = umcs7840_reg_sp(physport);

        if (umcs7840_calc_baudrate(rate, &divisor, &clk)) {
                DPRINTF(("Port %d bad speed: %d\n", portno, rate));
                return -1;
        }
        if (divisor == 0 || (clk & MCS7840_DEV_SPx_CLOCK_MASK) != clk) {
                DPRINTF(("Port %d bad speed calculation: %d\n", portno,
                    rate));
                return -1;
        }
        DPRINTF(("Port %d set speed: %d (%02x / %d)\n", portno, rate, clk, divisor));

        /* Set clock source for standard BAUD frequencies */
        err = umcs7840_get_reg(sc, spreg, &data);
        if (err)
                return err;
        data &= MCS7840_DEV_SPx_CLOCK_MASK;
        data |= clk;
        err = umcs7840_set_reg(sc, spreg, data);
        if (err)
                return err;

        /* Set divider */
        sc->sc_ports[portno].sc_port_lcr |= MCS7840_UART_LCR_DIVISORS;
        err = umcs7840_set_UART_reg(sc, physport, MCS7840_UART_REG_LCR, sc->sc_ports[portno].sc_port_lcr);
        if (err)
                return err;

        err = umcs7840_set_UART_reg(sc, physport, MCS7840_UART_REG_DLL, (uint8_t)(divisor & 0xff));
        if (err)
                return err;
        err = umcs7840_set_UART_reg(sc, physport, MCS7840_UART_REG_DLM, (uint8_t)((divisor >> 8) & 0xff));
        if (err)
                return err;

        /* Turn off access to DLL/DLM registers of UART */
        sc->sc_ports[portno].sc_port_lcr &= ~MCS7840_UART_LCR_DIVISORS;
        err = umcs7840_set_UART_reg(sc, physport, MCS7840_UART_REG_LCR, sc->sc_ports[portno].sc_port_lcr);
        if (err)
                return err;
        return 0;
}

static int
umcs7840_calc_baudrate(uint32_t rate, uint16_t *divisor, uint8_t *clk)
{
        /* Maximum speeds for standard frequencies, when PLL is not used */
        static const uint32_t umcs7840_baudrate_divisors[] =
            {0, 115200, 230400, 403200, 460800, 806400, 921600,
             1572864, 3145728,};
        static const uint8_t umcs7840_baudrate_divisors_len =
             __arraycount(umcs7840_baudrate_divisors);
        uint8_t i = 0;

        if (rate > umcs7840_baudrate_divisors[umcs7840_baudrate_divisors_len - 1])
                return -1;

        for (i = 0; i < umcs7840_baudrate_divisors_len - 1
             && !(rate > umcs7840_baudrate_divisors[i]
             && rate <= umcs7840_baudrate_divisors[i + 1]); ++i);
        *divisor = umcs7840_baudrate_divisors[i + 1] / rate;
        /* 0x00 .. 0x70 */
        *clk = i << MCS7840_DEV_SPx_CLOCK_SHIFT;
        return 0;
}

static int
umcs7840_detach(device_t self, int flags)
{
        struct umcs7840_softc *sc = device_private(self);
        int rv = 0, i;

        sc->sc_dying = true;

        /* close interrupt pipe */
        if (sc->sc_intr_pipe != NULL) {
                usbd_abort_pipe(sc->sc_intr_pipe);
                usbd_close_pipe(sc->sc_intr_pipe);
                sc->sc_intr_pipe = NULL;
        }
        if (sc->sc_intr_buf != NULL) {
                kmem_free(sc->sc_intr_buf, sc->sc_intr_buflen);
                sc->sc_intr_buf = NULL;
        }

        if (sc->sc_init_state < UMCS_INIT_INITED)
                return 0;

        usb_rem_task_wait(sc->sc_udev, &sc->sc_change_task, USB_TASKQ_DRIVER,
            NULL);

        /* detach children */
        for (i = 0; i < sc->sc_numports; i++) {
                if (sc->sc_ports[i].sc_port_ucom) {
                        rv |= config_detach(sc->sc_ports[i].sc_port_ucom,
                            flags);
                        sc->sc_ports[i].sc_port_ucom = NULL;
                }
        }

        usbd_add_drv_event(USB_EVENT_DRIVER_DETACH, sc->sc_udev, sc->sc_dev);

        return rv;
}

static void
umcs7840_childdet(device_t self, device_t child)
{
        struct umcs7840_softc *sc = device_private(self);
        int i;

        for (i = 0; i < sc->sc_numports; i++) {
                if (child == sc->sc_ports[i].sc_port_ucom) {
                        sc->sc_ports[i].sc_port_ucom = NULL;
                        return;
                }
        }
}

static void
umcs7840_get_status(void *self, int portno, u_char *lsr, u_char *msr)
{
        struct umcs7840_softc *sc = self;
        uint8_t pn = sc->sc_ports[portno].sc_port_phys;
        uint8_t hw_lsr = 0;     /* local line status register */
        uint8_t hw_msr = 0;     /* local modem status register */

        if (sc->sc_dying)
                return;

        /* Read LSR & MSR */
        umcs7840_get_UART_reg(sc, pn, MCS7840_UART_REG_LSR, &hw_lsr);
        umcs7840_get_UART_reg(sc, pn, MCS7840_UART_REG_MSR, &hw_msr);

        *lsr = hw_lsr;
        *msr = hw_msr;
}

static void
umcs7840_set(void *self, int portno, int reg, int onoff)
{
        struct umcs7840_softc *sc = self;

        if (sc->sc_dying)
                return;

        switch (reg) {
        case UCOM_SET_DTR:
                umcs7840_dtr(sc, portno, onoff);
                break;
        case UCOM_SET_RTS:
                umcs7840_rts(sc, portno, onoff);
                break;
        case UCOM_SET_BREAK:
                umcs7840_break(sc, portno, onoff);
                break;
        default:
                break;
        }
}

static int
umcs7840_param(void *self, int portno, struct termios *t)
{
        struct umcs7840_softc *sc = self;
        int pn = sc->sc_ports[portno].sc_port_phys;
        uint8_t lcr = sc->sc_ports[portno].sc_port_lcr;
        uint8_t mcr = sc->sc_ports[portno].sc_port_mcr;

        if (sc->sc_dying)
                return EIO;

        if (t->c_cflag & CSTOPB) {
                lcr |= MCS7840_UART_LCR_STOPB2;
        } else {
                lcr |= MCS7840_UART_LCR_STOPB1;
        }

        lcr &= ~MCS7840_UART_LCR_PARITYMASK;
        if (t->c_cflag & PARENB) {
                lcr |= MCS7840_UART_LCR_PARITYON;
                if (t->c_cflag & PARODD) {
                        lcr = MCS7840_UART_LCR_PARITYODD;
                } else {
                        lcr = MCS7840_UART_LCR_PARITYEVEN;
                }
        } else {
                lcr &= ~MCS7840_UART_LCR_PARITYON;
        }

        lcr &= ~MCS7840_UART_LCR_DATALENMASK;
        switch (t->c_cflag & CSIZE) {
        case CS5:
                lcr |= MCS7840_UART_LCR_DATALEN5;
                break;
        case CS6:
                lcr |= MCS7840_UART_LCR_DATALEN6;
                break;
        case CS7:
                lcr |= MCS7840_UART_LCR_DATALEN7;
                break;
        case CS8:
                lcr |= MCS7840_UART_LCR_DATALEN8;
                break;
        }

        if (t->c_cflag & CRTSCTS)
                mcr |= MCS7840_UART_MCR_CTSRTS;
        else
                mcr &= ~MCS7840_UART_MCR_CTSRTS;

        if (t->c_cflag & CLOCAL)
                mcr &= ~MCS7840_UART_MCR_DTRDSR;
        else
                mcr |= MCS7840_UART_MCR_DTRDSR;

        sc->sc_ports[portno].sc_port_lcr = lcr;
        umcs7840_set_UART_reg(sc, pn, MCS7840_UART_REG_LCR,
            sc->sc_ports[pn].sc_port_lcr);

        sc->sc_ports[portno].sc_port_mcr = mcr;
        umcs7840_set_UART_reg(sc, pn, MCS7840_UART_REG_MCR,
            sc->sc_ports[pn].sc_port_mcr);

        if (umcs7840_set_baudrate(sc, portno, t->c_ospeed))
                return EIO;

        return 0;
}

static void
umcs7840_dtr(struct umcs7840_softc *sc, int portno, bool onoff)
{
        int pn = sc->sc_ports[portno].sc_port_phys;
        uint8_t mcr = sc->sc_ports[portno].sc_port_mcr;

        if (onoff)
                mcr |= MCS7840_UART_MCR_DTR;
        else
                mcr &= ~MCS7840_UART_MCR_DTR;

        sc->sc_ports[portno].sc_port_mcr = mcr;
        umcs7840_set_UART_reg(sc, pn, MCS7840_UART_REG_MCR,
            sc->sc_ports[pn].sc_port_mcr);
}

static void
umcs7840_rts(struct umcs7840_softc *sc, int portno, bool onoff)
{
        int pn = sc->sc_ports[portno].sc_port_phys;
        uint8_t mcr = sc->sc_ports[portno].sc_port_mcr;

        if (onoff)
                mcr |= MCS7840_UART_MCR_RTS;
        else
                mcr &= ~MCS7840_UART_MCR_RTS;

        sc->sc_ports[portno].sc_port_mcr = mcr;
        umcs7840_set_UART_reg(sc, pn, MCS7840_UART_REG_MCR,
            sc->sc_ports[pn].sc_port_mcr);
}

static void
umcs7840_break(struct umcs7840_softc *sc, int portno, bool onoff)
{
        int pn = sc->sc_ports[portno].sc_port_phys;
        uint8_t lcr = sc->sc_ports[portno].sc_port_lcr;

        if (onoff)
                lcr |= MCS7840_UART_LCR_BREAK;
        else
                lcr &= ~MCS7840_UART_LCR_BREAK;

        sc->sc_ports[portno].sc_port_lcr = lcr;
        umcs7840_set_UART_reg(sc, pn, MCS7840_UART_REG_LCR,
            sc->sc_ports[pn].sc_port_lcr);
}

static int
umcs7840_port_open(void *self, int portno)
{
        struct umcs7840_softc *sc = self;
        int pn = sc->sc_ports[portno].sc_port_phys;
        int spreg = umcs7840_reg_sp(pn);
        int ctrlreg = umcs7840_reg_ctrl(pn);
        uint8_t data;

        if (sc->sc_dying)
                return EIO;

        /* If it very first open, finish global configuration */
        if (!sc->sc_init_done) {
                if (umcs7840_get_reg(sc, MCS7840_DEV_REG_CONTROL1, &data))
                        return EIO;
                data |= MCS7840_DEV_CONTROL1_DRIVER_DONE;
                if (umcs7840_set_reg(sc, MCS7840_DEV_REG_CONTROL1, data))
                        return EIO;
                sc->sc_init_done = 1;
        }

        /* Toggle reset bit on-off */
        if (umcs7840_get_reg(sc, spreg, &data))
                return EIO;
        data |= MCS7840_DEV_SPx_UART_RESET;
        if (umcs7840_set_reg(sc, spreg, data))
                return EIO;
        data &= ~MCS7840_DEV_SPx_UART_RESET;
        if (umcs7840_set_reg(sc, spreg, data))
                return EIO;

        /* Set RS-232 mode */
        if (umcs7840_set_UART_reg(sc, pn, MCS7840_UART_REG_SCRATCHPAD,
            MCS7840_UART_SCRATCHPAD_RS232))
                return EIO;

        /* Disable RX on time of initialization */
        if (umcs7840_get_reg(sc, ctrlreg, &data))
                return EIO;
        data |= MCS7840_DEV_CONTROLx_RX_DISABLE;
        if (umcs7840_set_reg(sc, ctrlreg, data))
                return EIO;

        /* Disable all interrupts */
        if (umcs7840_set_UART_reg(sc, pn, MCS7840_UART_REG_IER, 0))
                return EIO;

        /* Reset FIFO -- documented */
        if (umcs7840_set_UART_reg(sc, pn, MCS7840_UART_REG_FCR, 0))
                return EIO;
        if (umcs7840_set_UART_reg(sc, pn, MCS7840_UART_REG_FCR,
            MCS7840_UART_FCR_ENABLE | MCS7840_UART_FCR_FLUSHRHR |
            MCS7840_UART_FCR_FLUSHTHR | MCS7840_UART_FCR_RTL_1_14))
                return EIO;

        /* Set 8 bit, no parity, 1 stop bit -- documented */
        sc->sc_ports[pn].sc_port_lcr =
            MCS7840_UART_LCR_DATALEN8 | MCS7840_UART_LCR_STOPB1;
        if (umcs7840_set_UART_reg(sc, pn, MCS7840_UART_REG_LCR,
            sc->sc_ports[pn].sc_port_lcr))
                return EIO;

        /*
         * Enable DTR/RTS on modem control, enable modem interrupts --
         * documented
         */
        sc->sc_ports[pn].sc_port_mcr = MCS7840_UART_MCR_DTR
            | MCS7840_UART_MCR_RTS | MCS7840_UART_MCR_IE;
        if (umcs7840_set_UART_reg(sc, pn, MCS7840_UART_REG_MCR,
            sc->sc_ports[pn].sc_port_mcr))
                return EIO;

        /* Clearing Bulkin and Bulkout FIFO */
        if (umcs7840_get_reg(sc, spreg, &data))
                return EIO;
        data |= MCS7840_DEV_SPx_RESET_OUT_FIFO | MCS7840_DEV_SPx_RESET_IN_FIFO;
        if (umcs7840_set_reg(sc, spreg, data))
                return EIO;
        data &= ~(MCS7840_DEV_SPx_RESET_OUT_FIFO
            | MCS7840_DEV_SPx_RESET_IN_FIFO);
        if (umcs7840_set_reg(sc, spreg, data))
                return EIO;

        /* Set speed 9600 */
        if (umcs7840_set_baudrate(sc, portno, 9600))
                return EIO;


        /* Finally enable all interrupts -- documented */
        /*
         * Copied from vendor driver, I don't know why we should read LCR
         * here
         */
        if (umcs7840_get_UART_reg(sc, pn, MCS7840_UART_REG_LCR,
            &sc->sc_ports[pn].sc_port_lcr))
                return EIO;
        if (umcs7840_set_UART_reg(sc, pn, MCS7840_UART_REG_IER,
            MCS7840_UART_IER_RXSTAT | MCS7840_UART_IER_MODEM))
                return EIO;

        /* Enable RX */
        if (umcs7840_get_reg(sc, ctrlreg, &data))
                return EIO;
        data &= ~MCS7840_DEV_CONTROLx_RX_DISABLE;
        if (umcs7840_set_reg(sc, ctrlreg, data))
                return EIO;
        return 0;
}

static void
umcs7840_port_close(void *self, int portno)
{
        struct umcs7840_softc *sc = self;
        int pn = sc->sc_ports[portno].sc_port_phys;
        int ctrlreg = umcs7840_reg_ctrl(pn);
        uint8_t data;

        if (sc->sc_dying)
                return;

        umcs7840_set_UART_reg(sc, pn, MCS7840_UART_REG_MCR, 0);
        umcs7840_set_UART_reg(sc, pn, MCS7840_UART_REG_IER, 0);

        /* Disable RX */
        if (umcs7840_get_reg(sc, ctrlreg, &data))
                return;
        data |= MCS7840_DEV_CONTROLx_RX_DISABLE;
        if (umcs7840_set_reg(sc, ctrlreg, data))
                return;
}

static void
umcs7840_intr(struct usbd_xfer *xfer, void *priv,
    usbd_status status)
{
        struct umcs7840_softc *sc = priv;
        u_char *buf = sc->sc_intr_buf;
        int actlen;
        int subunit;

        if (sc->sc_dying)
                return;

        if (status == USBD_NOT_STARTED || status == USBD_CANCELLED
            || status == USBD_IOERROR)
                return;

        if (status != USBD_NORMAL_COMPLETION) {
                aprint_error_dev(sc->sc_dev,
                    "umcs7840_intr: abnormal status: %s\n",
                    usbd_errstr(status));
                usbd_clear_endpoint_stall_async(sc->sc_intr_pipe);
                return;
        }

        usbd_get_xfer_status(xfer, NULL, NULL, &actlen, NULL);
        if (actlen == 5 || actlen == 13) {
                uint32_t change_mask = 0;
                /* Check status of all ports */
                for (subunit = 0; subunit < sc->sc_numports; subunit++) {
                        uint8_t pn = sc->sc_ports[subunit].sc_port_phys;
                        if (buf[pn] & MCS7840_UART_ISR_NOPENDING)
                                continue;
                        DPRINTF(("Port %d has pending interrupt: %02x "
                            "(FIFO: %02x)\n", pn,
                            buf[pn] & MCS7840_UART_ISR_INTMASK,
                            buf[pn] & (~MCS7840_UART_ISR_INTMASK)));
                        switch (buf[pn] & MCS7840_UART_ISR_INTMASK) {
                        case MCS7840_UART_ISR_RXERR:
                        case MCS7840_UART_ISR_RXHASDATA:
                        case MCS7840_UART_ISR_RXTIMEOUT:
                        case MCS7840_UART_ISR_MSCHANGE:
                                change_mask |= (1U << subunit);
                                break;
                        default:
                                /* Do nothing */
                                break;
                        }
                }

                if (change_mask != 0) {
                        atomic_or_32(&sc->sc_change_mask, change_mask);
                        usb_add_task(sc->sc_udev, &sc->sc_change_task,
                            USB_TASKQ_DRIVER);
                }
        } else {
                aprint_error_dev(sc->sc_dev,
                   "Invalid interrupt data length %d", actlen);
        }
}

static void
umcs7840_change_task(void *arg)
{
        struct umcs7840_softc *sc = arg;
        uint32_t change_mask;
        int i;

        change_mask = atomic_swap_32(&sc->sc_change_mask, 0);
        for (i = 0; i < sc->sc_numports; i++) {
                if (ISSET(change_mask, (1U << i)))
                        ucom_status_change(device_private(
                            sc->sc_ports[i].sc_port_ucom));
        }
}