/* $NetBSD: meson_uart.c,v 1.8 2025/09/06 22:53:47 thorpej Exp $ */

/*-
 * Copyright (c) 2013 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Matt Thomas of 3am Software Foundry.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

#include "opt_console.h"
#include "locators.h"

#include <sys/cdefs.h>

__KERNEL_RCSID(1, "$NetBSD: meson_uart.c,v 1.8 2025/09/06 22:53:47 thorpej Exp $");

#define cn_trap()                       \
        do {                            \
                console_debugger();     \
                cn_trapped = 1;         \
        } while (/* CONSTCOND */ 0)

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/device.h>
#include <sys/conf.h>
#include <sys/intr.h>
#include <sys/systm.h>
#include <sys/time.h>
#include <sys/termios.h>
#include <sys/kauth.h>
#include <sys/lwp.h>
#include <sys/tty.h>

#include <ddb/db_active.h>

#include <dev/cons.h>

#include <dev/fdt/fdtvar.h>
#include <dev/fdt/fdt_console.h>

#include <arm/amlogic/meson_uart.h>

static int      meson_uart_match(device_t, cfdata_t, void *);
static void     meson_uart_attach(device_t, device_t, void *);

static int      meson_uart_intr(void *);
static void     meson_uart_rxsoft(void *);

static int      meson_uart_cngetc(dev_t);
static void     meson_uart_cnputc(dev_t, int);
static void     meson_uart_cnpollc(dev_t, int);

static void     meson_uart_start(struct tty *);
static int      meson_uart_param(struct tty *, struct termios *);

extern struct cfdriver mesonuart_cd;

static const struct device_compatible_entry compat_data[] = {
        { .compat = "amlogic,meson6-uart" },
        { .compat = "amlogic,meson8-uart" },
        { .compat = "amlogic,meson8b-uart" },
        { .compat = "amlogic,meson-gx-uart" },
        DEVICE_COMPAT_EOL
};

struct meson_uart_softc {
        device_t sc_dev;
        bus_space_tag_t sc_bst;
        bus_space_handle_t sc_bsh;
        kmutex_t sc_intr_lock;
        void *sc_ih;
        void *sc_sih;

        struct tty *sc_tty;

        int sc_ospeed;
        unsigned int sc_rbuf_w;         /* write ptr of sc_rbuf[] */
        unsigned int sc_rbuf_r;         /* read ptr of sc_rbuf[] */
        tcflag_t sc_cflag;

        u_char sc_buf[1024];
#define MESON_RBUFSZ    128             /* must be 2^n */
        u_char sc_rbuf[MESON_RBUFSZ];   /* good enough for sizeof RXFIFO */
};

static int meson_uart_console_phandle = -1;

static struct meson_uart_softc meson_uart_cnsc;

static struct cnm_state meson_uart_cnm_state;

struct consdev meson_uart_consdev = {
        .cn_getc = meson_uart_cngetc,
        .cn_putc = meson_uart_cnputc,
        .cn_pollc = meson_uart_cnpollc,
        .cn_dev = NODEV,
        .cn_pri = CN_NORMAL,
};

static dev_type_open(meson_uart_open);
static dev_type_open(meson_uart_close);
static dev_type_read(meson_uart_read);
static dev_type_write(meson_uart_write);
static dev_type_ioctl(meson_uart_ioctl);
static dev_type_tty(meson_uart_tty);
static dev_type_poll(meson_uart_poll);
static dev_type_stop(meson_uart_stop);

const struct cdevsw mesonuart_cdevsw = {
        .d_open = meson_uart_open,
        .d_close = meson_uart_close,
        .d_read = meson_uart_read,
        .d_write = meson_uart_write,
        .d_ioctl = meson_uart_ioctl,
        .d_stop = meson_uart_stop,
        .d_tty = meson_uart_tty,
        .d_poll = meson_uart_poll,
        .d_mmap = nommap,
        .d_kqfilter = ttykqfilter,
        .d_discard = nodiscard,
        .d_flag = D_TTY
};

static int meson_uart_cmajor = -1;

CFATTACH_DECL_NEW(meson_uart, sizeof(struct meson_uart_softc),
        meson_uart_match, meson_uart_attach, NULL, NULL);

static int
meson_uart_match(device_t parent, cfdata_t cf, void *aux)
{
        struct fdt_attach_args * const faa = aux;

        return of_compatible_match(faa->faa_phandle, compat_data);
}

static void
meson_uart_attach(device_t parent, device_t self, void *aux)
{
        struct meson_uart_softc * const sc = device_private(self);
        struct fdt_attach_args * const faa = aux;
        const int phandle = faa->faa_phandle;
        char intrstr[128];
        bus_addr_t addr;
        bus_size_t size;
        struct tty *tp;
        int major, minor, error;
        uint32_t misc, control;

        if (fdtbus_get_reg(phandle, 0, &addr, &size) != 0) {
                aprint_error(": couldn't get registers\n");
                return;
        }

        sc->sc_dev = self;
        sc->sc_bst = faa->faa_bst;

        error = bus_space_map(sc->sc_bst, addr, size, 0, &sc->sc_bsh);
        if (error != 0) {
                aprint_error(": couldn't map registers\n");
                return;
        }

        if (!fdtbus_intr_str(phandle, 0, intrstr, sizeof(intrstr))) {
                aprint_error(": failed to decode interrupt\n");
                return;
        }

        mutex_init(&sc->sc_intr_lock, MUTEX_DEFAULT, IPL_SERIAL);
        sc->sc_ih = fdtbus_intr_establish_xname(phandle, 0, IPL_SERIAL,
            FDT_INTR_MPSAFE, meson_uart_intr, sc, device_xname(self));
        if (sc->sc_ih == NULL) {
                aprint_error(": failed to establish interrupt on %s\n",
                    intrstr);
                return;
        }

        sc->sc_sih = softint_establish(SOFTINT_SERIAL, meson_uart_rxsoft, sc);
        if (sc->sc_sih == NULL) {
                aprint_error(": failed to establish softint\n");
                return;
        }

        if (meson_uart_cmajor == -1) {
                /* allocate a major number */
                int bmajor = -1, cmajor = -1;
                error = devsw_attach("mesonuart", NULL, &bmajor,
                    &mesonuart_cdevsw, &cmajor);
                if (error) {
                        aprint_error(": couldn't allocate major number\n");
                        return;
                }
                meson_uart_cmajor = cmajor;
        }

        major = cdevsw_lookup_major(&mesonuart_cdevsw);
        minor = device_unit(self);

        tp = sc->sc_tty = tty_alloc();
        tp->t_oproc = meson_uart_start;
        tp->t_param = meson_uart_param;
        tp->t_dev = makedev(major, minor);
        tp->t_sc = sc;
        tty_attach(tp);

        aprint_naive("\n");
        if (meson_uart_console_phandle == phandle) {
                cn_tab->cn_dev = tp->t_dev;
                aprint_normal(": console");
        }
        aprint_normal("\n");

        aprint_normal_dev(self, "interrupting on %s\n", intrstr);

        misc = bus_space_read_4(sc->sc_bst, sc->sc_bsh, UART_MISC_REG);
        misc &= ~UART_MISC_TX_IRQ_CNT;
        misc |= __SHIFTIN(0, UART_MISC_TX_IRQ_CNT);
        misc &= ~UART_MISC_RX_IRQ_CNT;
        misc |= __SHIFTIN(1, UART_MISC_RX_IRQ_CNT);
        bus_space_write_4(sc->sc_bst, sc->sc_bsh, UART_MISC_REG, misc);

        control = bus_space_read_4(sc->sc_bst, sc->sc_bsh, UART_CONTROL_REG);
        control &= ~(UART_CONTROL_TX_INT_EN|UART_CONTROL_RX_INT_EN);
        bus_space_write_4(sc->sc_bst, sc->sc_bsh, UART_CONTROL_REG, control);
}

static int
meson_uart_cngetc(dev_t dev)
{
        bus_space_tag_t bst = meson_uart_cnsc.sc_bst;
        bus_space_handle_t bsh = meson_uart_cnsc.sc_bsh;
        uint32_t status;
        int s, c;

        s = splserial();

        status = bus_space_read_4(bst, bsh, UART_STATUS_REG);
        if (status & UART_STATUS_RX_EMPTY) {
                splx(s);
                return -1;
        }

        c = bus_space_read_4(bst, bsh, UART_RFIFO_REG) & 0xff;
        if (!db_active) {
                int cn_trapped __unused = 0;
                cn_check_magic(dev, c, meson_uart_cnm_state);
        }

        splx(s);

        return c;
}

static void
meson_uart_cnputc(dev_t dev, int c)
{
        bus_space_tag_t bst = meson_uart_cnsc.sc_bst;
        bus_space_handle_t bsh = meson_uart_cnsc.sc_bsh;
        int s;

        s = splserial();

        while ((bus_space_read_4(bst, bsh, UART_STATUS_REG) & UART_STATUS_TX_FULL) != 0)
                ;

        bus_space_write_4(bst, bsh, UART_WFIFO_REG, c);

        splx(s);
}
        

static void
meson_uart_cnpollc(dev_t dev, int on)
{
}

static int
meson_uart_open(dev_t dev, int flag, int mode, lwp_t *l)
{
        struct meson_uart_softc *sc =
            device_lookup_private(&mesonuart_cd, minor(dev));
        struct tty *tp = sc->sc_tty;
        uint32_t control;

        if (kauth_authorize_device_tty(l->l_cred,
            KAUTH_DEVICE_TTY_OPEN, tp) != 0) {
                return EBUSY;
        }

        if ((tp->t_state & TS_ISOPEN) == 0 && tp->t_wopen == 0) {
                tp->t_dev = dev;
                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 = TTYDEF_SPEED;
                ttsetwater(tp);

                control = bus_space_read_4(sc->sc_bst, sc->sc_bsh, UART_CONTROL_REG);
                control |= UART_CONTROL_RX_INT_EN;
                bus_space_write_4(sc->sc_bst, sc->sc_bsh, UART_CONTROL_REG, control);
        }
        tp->t_state |= TS_CARR_ON;

        return tp->t_linesw->l_open(dev, tp);
}

static int
meson_uart_close(dev_t dev, int flag, int mode, lwp_t *l)
{
        struct meson_uart_softc *sc =
            device_lookup_private(&mesonuart_cd, minor(dev));
        struct tty *tp = sc->sc_tty;
        uint32_t control;

        tp->t_linesw->l_close(tp, flag);
        ttyclose(tp);

        if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
                control = bus_space_read_4(sc->sc_bst, sc->sc_bsh, UART_CONTROL_REG);
                control &= ~UART_CONTROL_RX_INT_EN;
                bus_space_write_4(sc->sc_bst, sc->sc_bsh, UART_CONTROL_REG, control);
        }

        return 0;
}

static int
meson_uart_read(dev_t dev, struct uio *uio, int flag)
{
        struct meson_uart_softc *sc =
            device_lookup_private(&mesonuart_cd, minor(dev));
        struct tty *tp = sc->sc_tty;

        return tp->t_linesw->l_read(tp, uio, flag);
}

static int
meson_uart_write(dev_t dev, struct uio *uio, int flag)
{
        struct meson_uart_softc *sc =
            device_lookup_private(&mesonuart_cd, minor(dev));
        struct tty *tp = sc->sc_tty;

        return tp->t_linesw->l_write(tp, uio, flag);
}

static int
meson_uart_poll(dev_t dev, int events, lwp_t *l)
{
        struct meson_uart_softc *sc =
            device_lookup_private(&mesonuart_cd, minor(dev));
        struct tty *tp = sc->sc_tty;

        return tp->t_linesw->l_poll(tp, events, l);
}

static int
meson_uart_ioctl(dev_t dev, u_long cmd, void *data, int flag, lwp_t *l)
{
        struct meson_uart_softc *sc =
            device_lookup_private(&mesonuart_cd, minor(dev));
        struct tty *tp = sc->sc_tty;
        int error;

        error = tp->t_linesw->l_ioctl(tp, cmd, data, flag, l);
        if (error != EPASSTHROUGH)
                return error;

        return ttioctl(tp, cmd, data, flag, l);
}

static struct tty *
meson_uart_tty(dev_t dev)
{
        struct meson_uart_softc *sc =
            device_lookup_private(&mesonuart_cd, minor(dev));

        return sc->sc_tty;
}

static void
meson_uart_stop(struct tty *tp, int flag)
{
}

static void
meson_uart_start(struct tty *tp)
{
        struct meson_uart_softc *sc = tp->t_sc;
        u_char *p = sc->sc_buf;
        int s, brem;

        s = spltty();

        if (tp->t_state & (TS_TTSTOP | TS_BUSY | TS_TIMEOUT)) {
                splx(s);
                return;
        }
        tp->t_state |= TS_BUSY;

        splx(s);

        for (brem = q_to_b(&tp->t_outq, sc->sc_buf, sizeof(sc->sc_buf));
             brem > 0;
             brem--, p++) {
                while ((bus_space_read_4(sc->sc_bst, sc->sc_bsh,
                    UART_STATUS_REG) & UART_STATUS_TX_FULL) != 0)
                        ;

                bus_space_write_4(sc->sc_bst, sc->sc_bsh,
                    UART_WFIFO_REG, *p);
        }

        s = spltty();
        tp->t_state &= ~TS_BUSY;
        if (ttypull(tp)) {
                tp->t_state |= TS_TIMEOUT;
                callout_schedule(&tp->t_rstrt_ch, 1);
        }
        splx(s);
}

static int
meson_uart_param(struct tty *tp, struct termios *t)
{

        tp->t_ispeed = t->c_ispeed;
        tp->t_ospeed = t->c_ospeed;
        tp->t_cflag = t->c_cflag;

        return 0;
}

static int
meson_uart_intr(void *priv)
{
        struct meson_uart_softc *sc = priv;
        struct tty *tp = sc->sc_tty;
        uint32_t status, c;

        mutex_spin_enter(&sc->sc_intr_lock);
        for (;;) {
                int cn_trapped = 0;
                status = bus_space_read_4(sc->sc_bst, sc->sc_bsh,
                    UART_STATUS_REG);
                if (status & UART_STATUS_RX_EMPTY) {
                        break;
                }
                if (status & UART_STATUS_BREAK) {
                        cn_check_magic(tp->t_dev, CNC_BREAK,
                            meson_uart_cnm_state);
                        if (cn_trapped)
                                continue;
                }

                c = bus_space_read_4(sc->sc_bst, sc->sc_bsh, UART_RFIFO_REG);
                cn_check_magic(tp->t_dev, c & 0xff, meson_uart_cnm_state);
                if (cn_trapped)
                        continue;

                if ((sc->sc_rbuf_w - sc->sc_rbuf_r) >= (MESON_RBUFSZ - 1))
                        continue;
                sc->sc_rbuf[sc->sc_rbuf_w++ & (MESON_RBUFSZ - 1)] = c;
        }
        mutex_spin_exit(&sc->sc_intr_lock);

        if (sc->sc_rbuf_w != sc->sc_rbuf_r)
                softint_schedule(sc->sc_sih);

        return 0;
}

static void
meson_uart_rxsoft(void *priv)
{
        struct meson_uart_softc *sc = priv;
        struct tty *tp = sc->sc_tty;
        int c;

        while (sc->sc_rbuf_w != sc->sc_rbuf_r) {
                c = sc->sc_rbuf[sc->sc_rbuf_r++ & (MESON_RBUFSZ - 1)];
                if (tp->t_linesw->l_rint(c & 0xff, tp) == -1)
                        break;
        }
}

static int
meson_uart_console_match(int phandle)
{
        return of_compatible_match(phandle, compat_data);
}

static void
meson_uart_console_consinit(struct fdt_attach_args *faa, u_int uart_freq)
{
        struct meson_uart_softc *sc = &meson_uart_cnsc;
        const int phandle = faa->faa_phandle;
        bus_addr_t addr;
        bus_size_t size;
        int error;

        fdtbus_get_reg(phandle, 0, &addr, &size);

        sc->sc_bst = faa->faa_bst;
        sc->sc_ospeed = fdtbus_get_stdout_speed();
        if (sc->sc_ospeed < 0)
                sc->sc_ospeed = 115200;
        sc->sc_cflag = fdtbus_get_stdout_flags();

        error = bus_space_map(sc->sc_bst, addr, size, 0, &sc->sc_bsh);
        if (error != 0)
                panic("failed to map console, error = %d", error);

        cn_tab = &meson_uart_consdev;
        cn_init_magic(&meson_uart_cnm_state);
        cn_set_magic("\047\001");

        meson_uart_console_phandle = phandle;
}

static const struct fdt_console meson_uart_console = {
        .match = meson_uart_console_match,
        .consinit = meson_uart_console_consinit,
};

FDT_CONSOLE(meson_uart, &meson_uart_console);