/* $OpenBSD: mvuart.c,v 1.4 2021/10/24 17:52:26 mpi Exp $ */
/*
 * Copyright (c) 2005 Dale Rahn <drahn@motorola.com>
 * Copyright (c) 2018 Patrick Wildt <patrick@blueri.se>
 *
 * 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/param.h>
#include <sys/ioctl.h>
#include <sys/proc.h>
#include <sys/tty.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/conf.h>
#include <sys/fcntl.h>

#include <machine/bus.h>
#include <machine/fdt.h>

#include <dev/cons.h>

#include <dev/ofw/openfirm.h>
#include <dev/ofw/ofw_clock.h>
#include <dev/ofw/ofw_pinctrl.h>
#include <dev/ofw/fdt.h>

#define MVUART_RBR                      0x00
#define MVUART_TSH                      0x04
#define MVUART_CTRL                     0x08
#define  MVUART_CTRL_RX_RDY_INT                 (1 << 4)
#define  MVUART_CTRL_TX_RDY_INT                 (1 << 5)
#define MVUART_STAT                     0x0c
#define  MVUART_STAT_STD_OVR_ERR                (1 << 0)
#define  MVUART_STAT_STD_PAR_ERR                (1 << 1)
#define  MVUART_STAT_STD_FRM_ERR                (1 << 2)
#define  MVUART_STAT_STD_BRK_DET                (1 << 3)
#define  MVUART_STAT_STD_ERROR_MASK             (0xf << 0)
#define  MVUART_STAT_STD_RX_RDY                 (1 << 4)
#define  MVUART_STAT_STD_TX_RDY                 (1 << 5)
#define  MVUART_STAT_STD_TX_EMPTY               (1 << 6)
#define  MVUART_STAT_STD_TX_FIFO_FULL           (1 << 11)
#define  MVUART_STAT_STD_TX_FIFO_EMPTY          (1 << 13)
#define MVUART_BAUD_RATE_DIV            0x10
#define  MVUART_BAUD_RATE_DIV_MASK              0x3ff

#define DEVUNIT(x)      (minor(x) & 0x7f)
#define DEVCUA(x)       (minor(x) & 0x80)

#define HREAD4(sc, reg)                                                 \
        (bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, (reg)))
#define HWRITE4(sc, reg, val)                                           \
        bus_space_write_4((sc)->sc_iot, (sc)->sc_ioh, (reg), (val))
#define HSET4(sc, reg, bits)                                            \
        HWRITE4((sc), (reg), HREAD4((sc), (reg)) | (bits))
#define HCLR4(sc, reg, bits)                                            \
        HWRITE4((sc), (reg), HREAD4((sc), (reg)) & ~(bits))

struct mvuart_softc {
        struct device            sc_dev;
        bus_space_tag_t          sc_iot;
        bus_space_handle_t       sc_ioh;
        int                      sc_node;
        struct soft_intrhand    *sc_si;
        void                    *sc_ih;
        struct tty              *sc_tty;
        int                      sc_floods;
        int                      sc_errors;
        int                      sc_halt;
        uint8_t                  sc_hwflags;
#define COM_HW_NOIEN                    0x01
#define COM_HW_FIFO                     0x02
#define COM_HW_SIR                      0x20
#define COM_HW_CONSOLE                  0x40
        uint8_t                  sc_cua;
        uint16_t                *sc_ibuf, *sc_ibufp, *sc_ibufhigh, *sc_ibufend;
#define MVUART_IBUFSIZE                  128
#define MVUART_IHIGHWATER                100
        uint16_t                 sc_ibufs[2][MVUART_IBUFSIZE];
};

int      mvuart_match(struct device *, void *, void *);
void     mvuart_attach(struct device *, struct device *, void *);

void     mvuartcnprobe(struct consdev *cp);
void     mvuartcninit(struct consdev *cp);
int      mvuartcnattach(bus_space_tag_t, bus_addr_t, int, tcflag_t);
int      mvuartcngetc(dev_t dev);
void     mvuartcnputc(dev_t dev, int c);
void     mvuartcnpollc(dev_t dev, int on);
int      mvuart_param(struct tty *, struct termios *);
void     mvuart_start(struct tty *);
void     mvuart_softint(void *arg);

struct mvuart_softc *mvuart_sc(dev_t dev);

int      mvuart_intr(void *);
int      mvuart_intr_rx(struct mvuart_softc *);
int      mvuart_intr_tx(struct mvuart_softc *);

/* XXX - we imitate 'com' serial ports and take over their entry points */
/* XXX: These belong elsewhere */
cdev_decl(com);
cdev_decl(mvuart);

struct cfdriver mvuart_cd = {
        NULL, "mvuart", DV_TTY
};

const struct cfattach mvuart_ca = {
        sizeof(struct mvuart_softc), mvuart_match, mvuart_attach
};

bus_space_tag_t         mvuartconsiot;
bus_space_handle_t      mvuartconsioh;
bus_addr_t              mvuartconsaddr;

struct cdevsw mvuartdev =
        cdev_tty_init(3/*XXX NMVUART */, mvuart);               /* 12: serial port */

void
mvuart_init_cons(void)
{
        struct fdt_reg reg;
        void *node;

        if ((node = fdt_find_cons("marvell,armada-3700-uart")) == NULL)
                return;

        if (fdt_get_reg(node, 0, &reg))
                return;

        mvuartcnattach(fdt_cons_bs_tag, reg.addr, B115200, TTYDEF_CFLAG);
}

int
mvuart_match(struct device *parent, void *match, void *aux)
{
        struct fdt_attach_args *faa = aux;

        return OF_is_compatible(faa->fa_node, "marvell,armada-3700-uart");
}

void
mvuart_attach(struct device *parent, struct device *self, void *aux)
{
        struct mvuart_softc *sc = (struct mvuart_softc *)self;
        struct fdt_attach_args *faa = aux;
        int maj;

        if (faa->fa_nreg < 1)
                return;

        pinctrl_byname(faa->fa_node, "default");

        sc->sc_node = faa->fa_node;
        sc->sc_iot = faa->fa_iot;
        if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr,
            faa->fa_reg[0].size, 0, &sc->sc_ioh)) {
                panic("%s: bus_space_map failed", sc->sc_dev.dv_xname);
                return;
        }

        if (faa->fa_reg[0].addr == mvuartconsaddr) {
                /* Locate the major number. */
                for (maj = 0; maj < nchrdev; maj++)
                        if (cdevsw[maj].d_open == mvuartopen)
                                break;
                cn_tab->cn_dev = makedev(maj, sc->sc_dev.dv_unit);

                printf(": console");
        }

        printf("\n");

        sc->sc_ih = fdt_intr_establish_idx(faa->fa_node, 0, IPL_TTY,
            mvuart_intr, sc, sc->sc_dev.dv_xname);
        if (sc->sc_ih == NULL)
                panic("%s: can't establish hard interrupt",
                    sc->sc_dev.dv_xname);

        sc->sc_si = softintr_establish(IPL_TTY, mvuart_softint, sc);
        if (sc->sc_si == NULL)
                panic("%s: can't establish soft interrupt",
                    sc->sc_dev.dv_xname);
}

int
mvuart_intr(void *arg)
{
        struct mvuart_softc *sc = arg;
        uint32_t stat;
        int ret = 0;

        if (sc->sc_tty == NULL)
                return 0;

        stat = HREAD4(sc, MVUART_STAT);

        if ((stat & MVUART_STAT_STD_RX_RDY) != 0)
                ret |= mvuart_intr_rx(sc);

        if ((stat & MVUART_STAT_STD_TX_RDY) != 0)
                ret |= mvuart_intr_tx(sc);

        return ret;
}

int
mvuart_intr_rx(struct mvuart_softc *sc)
{
        uint32_t stat;
        uint16_t *p, c;

        p = sc->sc_ibufp;

        stat = HREAD4(sc, MVUART_STAT);
        while ((stat & MVUART_STAT_STD_RX_RDY) != 0) {
                c = HREAD4(sc, MVUART_RBR);
                c |= (stat & MVUART_STAT_STD_ERROR_MASK) << 8;
                if (p >= sc->sc_ibufend) {
                        sc->sc_floods++;
                } else {
                        *p++ = c;
                }
                stat = HREAD4(sc, MVUART_STAT);
        }
        sc->sc_ibufp = p;

        softintr_schedule(sc->sc_si);
        return 1;
}

int
mvuart_intr_tx(struct mvuart_softc *sc)
{
        struct tty *tp = sc->sc_tty;

        HCLR4(sc, MVUART_CTRL, MVUART_CTRL_TX_RDY_INT);
        if (ISSET(tp->t_state, TS_BUSY)) {
                CLR(tp->t_state, TS_BUSY | TS_FLUSH);
                if (sc->sc_halt > 0)
                        wakeup(&tp->t_outq);
                (*linesw[tp->t_line].l_start)(tp);
        }

        return 1;
}

int
mvuart_param(struct tty *tp, struct termios *t)
{
        struct mvuart_softc *sc = mvuart_sc(tp->t_dev);
        int error, ospeed = t->c_ospeed;
        tcflag_t oldcflag;

        if (t->c_ospeed < 0 || (t->c_ispeed && t->c_ispeed != t->c_ospeed))
                return EINVAL;

        switch (ISSET(t->c_cflag, CSIZE)) {
        case CS5:
        case CS6:
        case CS7:
                return EINVAL;
        case CS8:
                break;
        }

        if (ospeed != 0) {
                while (ISSET(tp->t_state, TS_BUSY)) {
                        ++sc->sc_halt;
                        error = ttysleep(tp, &tp->t_outq,
                            TTOPRI | PCATCH, "mvuartprm");
                        --sc->sc_halt;
                        if (error) {
                                mvuart_start(tp);
                                return (error);
                        }
                }
        }

        /* and copy to tty */
        tp->t_ispeed = t->c_ispeed;
        tp->t_ospeed = t->c_ospeed;
        oldcflag = tp->t_cflag;
        tp->t_cflag = t->c_cflag;

        mvuart_start(tp);
        return 0;
}

void
mvuart_start(struct tty *tp)
{
        struct mvuart_softc *sc = mvuart_sc(tp->t_dev);
        uint8_t buf;
        int i, n, s;

        s = spltty();
        if (ISSET(tp->t_state, TS_BUSY)) {
                splx(s);
                return;
        }
        if (ISSET(tp->t_state, TS_TIMEOUT | TS_TTSTOP))
                goto out;
        if (tp->t_outq.c_cc <= tp->t_lowat) {
                if (ISSET(tp->t_state, TS_ASLEEP)) {
                        CLR(tp->t_state, TS_ASLEEP);
                        wakeup(&tp->t_outq);
                }
                if (tp->t_outq.c_cc == 0)
                        goto out;
                selwakeup(&tp->t_wsel);
        }
        SET(tp->t_state, TS_BUSY);

        for (i = 0; i < 32; i++) {
                n = q_to_b(&tp->t_outq, &buf, 1);
                if (n < 1)
                        break;
                HWRITE4(sc, MVUART_TSH, buf);
                if (HREAD4(sc, MVUART_STAT) & MVUART_STAT_STD_TX_FIFO_FULL)
                        break;
        }
        HSET4(sc, MVUART_CTRL, MVUART_CTRL_TX_RDY_INT);

out:
        splx(s);
}

void
mvuart_softint(void *arg)
{
        struct mvuart_softc *sc = arg;
        struct tty *tp;
        uint16_t *ibufp;
        uint16_t *ibufend;
        int c, err, s;

        if (sc == NULL || sc->sc_ibufp == sc->sc_ibuf)
                return;

        tp = sc->sc_tty;
        s = spltty();

        ibufp = sc->sc_ibuf;
        ibufend = sc->sc_ibufp;

        if (ibufp == ibufend || tp == NULL || !ISSET(tp->t_state, TS_ISOPEN)) {
                splx(s);
                return;
        }

        sc->sc_ibufp = sc->sc_ibuf = (ibufp == sc->sc_ibufs[0]) ?
            sc->sc_ibufs[1] : sc->sc_ibufs[0];
        sc->sc_ibufhigh = sc->sc_ibuf + MVUART_IHIGHWATER;
        sc->sc_ibufend = sc->sc_ibuf + MVUART_IBUFSIZE;

        splx(s);

        while (ibufp < ibufend) {
                err = 0;
                c = *ibufp++;
                if (ISSET(c, (MVUART_STAT_STD_PAR_ERR << 8)))
                        err |= TTY_PE;
                if (ISSET(c, (MVUART_STAT_STD_FRM_ERR << 8)))
                        err |= TTY_FE;
                c = (c & 0xff) | err;
                (*linesw[tp->t_line].l_rint)(c, tp);
        }
}

int
mvuartopen(dev_t dev, int flag, int mode, struct proc *p)
{
        struct mvuart_softc *sc;
        struct tty *tp;
        int s, error = 0;

        sc = mvuart_sc(dev);
        if (sc == NULL)
                return ENXIO;

        s = spltty();
        if (sc->sc_tty == NULL)
                tp = sc->sc_tty = ttymalloc(0);
        else
                tp = sc->sc_tty;

        splx(s);

        tp->t_oproc = mvuart_start;
        tp->t_param = mvuart_param;
        tp->t_dev = dev;

        if (!ISSET(tp->t_state, TS_ISOPEN)) {
                SET(tp->t_state, TS_WOPEN);
                ttychars(tp);
                tp->t_iflag = TTYDEF_IFLAG;
                tp->t_oflag = TTYDEF_OFLAG;

                tp->t_cflag = TTYDEF_CFLAG;
                tp->t_lflag = TTYDEF_LFLAG;
                tp->t_ispeed = tp->t_ospeed = B115200;

                s = spltty();

                mvuart_param(tp, &tp->t_termios);
                ttsetwater(tp);
                sc->sc_ibufp = sc->sc_ibuf = sc->sc_ibufs[0];
                sc->sc_ibufhigh = sc->sc_ibuf + MVUART_IHIGHWATER;
                sc->sc_ibufend = sc->sc_ibuf + MVUART_IBUFSIZE;

                /* Enable interrupts */
                HSET4(sc, MVUART_CTRL, MVUART_CTRL_RX_RDY_INT);

                SET(tp->t_state, TS_CARR_ON); /* XXX */
        } else if (ISSET(tp->t_state, TS_XCLUDE) && suser(p) != 0)
                return EBUSY;
        else
                s = spltty();

        if (DEVCUA(dev)) {
                if (ISSET(tp->t_state, TS_ISOPEN)) {
                        splx(s);
                        return EBUSY;
                }
                sc->sc_cua = 1;
        } else {
                /* tty (not cua) device; wait for carrier if necessary */
                if (ISSET(flag, O_NONBLOCK)) {
                        if (sc->sc_cua) {
                                /* Opening TTY non-blocking... but the CUA is busy */
                                splx(s);
                                return EBUSY;
                        }
                } else {
                        while (sc->sc_cua ||
                            (!ISSET(tp->t_cflag, CLOCAL) &&
                                !ISSET(tp->t_state, TS_CARR_ON))) {
                                SET(tp->t_state, TS_WOPEN);
                                error = ttysleep(tp, &tp->t_rawq,
                                    TTIPRI | PCATCH, ttopen);
                                /*
                                 * If TS_WOPEN has been reset, that means the
                                 * cua device has been closed.  We don't want
                                 * to fail in that case,
                                 * so just go around again.
                                 */
                                if (error && ISSET(tp->t_state, TS_WOPEN)) {
                                        CLR(tp->t_state, TS_WOPEN);
                                        splx(s);
                                        return error;
                                }
                        }
                }
        }
        splx(s);
        return (*linesw[tp->t_line].l_open)(dev,tp,p);
}

int
mvuartclose(dev_t dev, int flag, int mode, struct proc *p)
{
        struct mvuart_softc *sc = mvuart_sc(dev);
        struct tty *tp = sc->sc_tty;
        int s;

        if (!ISSET(tp->t_state, TS_ISOPEN))
                return 0;

        (*linesw[tp->t_line].l_close)(tp, flag, p);
        s = spltty();
        if (!ISSET(tp->t_state, TS_WOPEN)) {
                /* Disable interrupts */
                HCLR4(sc, MVUART_CTRL, MVUART_CTRL_RX_RDY_INT |
                    MVUART_CTRL_TX_RDY_INT);
        }
        CLR(tp->t_state, TS_BUSY | TS_FLUSH);
        sc->sc_cua = 0;
        splx(s);
        ttyclose(tp);

        return 0;
}

int
mvuartread(dev_t dev, struct uio *uio, int flag)
{
        struct tty *tty;

        tty = mvuarttty(dev);
        if (tty == NULL)
                return ENODEV;

        return((*linesw[tty->t_line].l_read)(tty, uio, flag));
}

int
mvuartwrite(dev_t dev, struct uio *uio, int flag)
{
        struct tty *tty;

        tty = mvuarttty(dev);
        if (tty == NULL)
                return ENODEV;

        return((*linesw[tty->t_line].l_write)(tty, uio, flag));
}

int
mvuartioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
{
        struct mvuart_softc *sc;
        struct tty *tp;
        int error;

        sc = mvuart_sc(dev);
        if (sc == NULL)
                return (ENODEV);

        tp = sc->sc_tty;
        if (tp == NULL)
                return (ENXIO);

        error = (*linesw[tp->t_line].l_ioctl)(tp, cmd, data, flag, p);
        if (error >= 0)
                return (error);

        error = ttioctl(tp, cmd, data, flag, p);
        if (error >= 0)
                return (error);

        switch(cmd) {
        case TIOCSBRK:
        case TIOCCBRK:
        case TIOCSDTR:
        case TIOCCDTR:
        case TIOCMSET:
        case TIOCMBIS:
        case TIOCMBIC:
        case TIOCMGET:
        case TIOCGFLAGS:
                break;
        case TIOCSFLAGS:
                error = suser(p);
                if (error != 0)
                        return(EPERM);
                break;
        default:
                return (ENOTTY);
        }

        return 0;
}

int
mvuartstop(struct tty *tp, int flag)
{
        return 0;
}

struct tty *
mvuarttty(dev_t dev)
{
        struct mvuart_softc *sc;
        sc = mvuart_sc(dev);
        if (sc == NULL)
                return NULL;
        return sc->sc_tty;
}

struct mvuart_softc *
mvuart_sc(dev_t dev)
{
        int unit;
        unit = DEVUNIT(dev);
        if (unit >= mvuart_cd.cd_ndevs)
                return NULL;
        return (struct mvuart_softc *)mvuart_cd.cd_devs[unit];
}

/* serial console */
void
mvuartcnprobe(struct consdev *cp)
{
}

void
mvuartcninit(struct consdev *cp)
{
}

int
mvuartcnattach(bus_space_tag_t iot, bus_addr_t iobase, int rate, tcflag_t cflag)
{
        static struct consdev mvuartcons = {
                NULL, NULL, mvuartcngetc, mvuartcnputc, mvuartcnpollc, NULL,
                NODEV, CN_MIDPRI
        };
        int maj;

        if (bus_space_map(iot, iobase, 0x200, 0, &mvuartconsioh))
                return ENOMEM;

        /* Look for major of com(4) to replace. */
        for (maj = 0; maj < nchrdev; maj++)
                if (cdevsw[maj].d_open == comopen)
                        break;
        if (maj == nchrdev)
                return ENXIO;

        cn_tab = &mvuartcons;
        cn_tab->cn_dev = makedev(maj, 0);
        cdevsw[maj] = mvuartdev;        /* KLUDGE */

        mvuartconsiot = iot;
        mvuartconsaddr = iobase;

        return 0;
}

int
mvuartcngetc(dev_t dev)
{
        int c;
        int s;
        s = splhigh();
        while ((bus_space_read_4(mvuartconsiot, mvuartconsioh, MVUART_STAT) &
            MVUART_STAT_STD_RX_RDY) == 0)
                ;
        c = bus_space_read_4(mvuartconsiot, mvuartconsioh, MVUART_RBR);
        splx(s);
        return c;
}

void
mvuartcnputc(dev_t dev, int c)
{
        int s;
        s = splhigh();
        while ((bus_space_read_4(mvuartconsiot, mvuartconsioh, MVUART_STAT) &
            MVUART_STAT_STD_TX_FIFO_FULL) != 0)
                ;
        bus_space_write_4(mvuartconsiot, mvuartconsioh, MVUART_TSH, (uint8_t)c);
        while ((bus_space_read_4(mvuartconsiot, mvuartconsioh, MVUART_STAT) &
            MVUART_STAT_STD_TX_FIFO_EMPTY) != 0)
                ;
        splx(s);
}

void
mvuartcnpollc(dev_t dev, int on)
{
}