/* $NetBSD: stasc.c,v 1.3 2024/02/08 10:30:25 andvar Exp $ */
/*
 * Copyright (c) 2020 Valery Ushakov
 * 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 ``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 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.
 */

/*
 * STMicroelectronics ST40 Asynchronous Serial Controller
 */
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: stasc.c,v 1.3 2024/02/08 10:30:25 andvar Exp $");

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

#include <dev/cons.h>


#define STM_ASC_BASE    0xfd032000

#define ASC_BAUDRATE_OFFSET     0x00
#define ASC_TX_BUFF_OFFSET      0x04
#define ASC_RX_BUFF_OFFSET      0x08
#define ASC_CTRL_OFFSET         0x0C
#define ASC_INT_EN_OFFSET       0x10
#define ASC_INT_STA_OFFSET      0x14
#define ASC_GUARDTIME_OFFSET    0x18
#define ASC_TIMEOUT_OFFSET      0x1C
#define ASC_TX_RST_OFFSET       0x20
#define ASC_RX_RST_OFFSET       0x24
#define ASC_RETRIES_OFFSET      0x28

#define ASC_TX_BUFF     (*(volatile uint32_t *)(STM_ASC_BASE + ASC_TX_BUFF_OFFSET))
#define ASC_RX_BUFF     (*(volatile uint32_t *)(STM_ASC_BASE + ASC_RX_BUFF_OFFSET))
#define ASC_INT_EN      (*(volatile uint32_t *)(STM_ASC_BASE + ASC_INT_EN_OFFSET))
#define ASC_INT_STA     (*(volatile uint32_t *)(STM_ASC_BASE + ASC_INT_STA_OFFSET))


#define ASC_CTRL_NACK_DISABLE   0x2000
#define ASC_CTRL_BAUDMODE       0x1000
#define ASC_CTRL_CTS_EN         0x0800
#define ASC_CTRL_FIFO_EN        0x0400
#define ASC_CTRL_SC_EN          0x0200
#define ASC_CTRL_RX_EN          0x0100
#define ASC_CTRL_RUN            0x0080
#define ASC_CTRL_LOOPBACK       0x0040
#define ASC_CTRL_PARITYODD      0x0020
#define ASC_CTRL_STOPBITS_MASK  0x0018
#define     ASC_CTRL_STOPBITS_0_5       0x0000
#define     ASC_CTRL_STOPBITS_1_0       0x0008
#define     ASC_CTRL_STOPBITS_1_5       0x0010
#define     ASC_CTRL_STOPBITS_2_0       0x0018
#define ASC_CTRL_MODE_MASK      0x0007
#define     ASC_CTRL_MODE_8N            0x0001 /* 8 bit */
#define     ASC_CTRL_MODE_7P            0x0003 /* 7 bit + parity  */
#define     ASC_CTRL_MODE_9N            0x0004 /* 9 bit */
#define     ASC_CTRL_MODE_8W            0x0005 /* 8 bit + wakeup */
#define     ASC_CTRL_MODE_8P            0x0007 /* 8 bit + parity */


#define ASC_INT_EN_RHF          0x0100 /* ASC_INT_STA_RHF */
#define ASC_INT_EN_TOE          0x0080 /* ASC_INT_STA_TOE */
#define ASC_INT_EN_TNE          0x0040 /* ASC_INT_STA_TNE */
#define ASC_INT_EN_OE           0x0020 /* ASC_INT_STA_OE */
#define ASC_INT_EN_FE           0x0010 /* ASC_INT_STA_FE */
#define ASC_INT_EN_PE           0x0008 /* ASC_INT_STA_PE */
#define ASC_INT_EN_THE          0x0004 /* ASC_INT_STA_THE */
#define ASC_INT_EN_TE           0x0002 /* ASC_INT_STA_TE */
#define ASC_INT_EN_RBF          0x0001 /* ASC_INT_STA_RBF */

#define ASC_INT_STA_NKD         0x0400 /* Tx: NACK Data */
#define ASC_INT_STA_TF          0x0200 /* Tx: Transmitter Full */
#define ASC_INT_STA_RHF         0x0100 /* Rx: Receiver FIFO Half Full */
#define ASC_INT_STA_TOE         0x0080 /* Rx: Timeout Or Empty */
#define ASC_INT_STA_TNE         0x0040 /* Rx: Timeout Or Not Empty */
#define ASC_INT_STA_OE          0x0020 /* Rx: Overrun Error */
#define ASC_INT_STA_FE          0x0010 /* Rx: Frame Error */
#define ASC_INT_STA_PE          0x0008 /* Rx: Parity Error */
#define ASC_INT_STA_THE         0x0004 /* Tx: Transmitter FIFO Half Empty */
#define ASC_INT_STA_TE          0x0002 /* Tx: Transmitter Empty */
#define ASC_INT_STA_RBF         0x0001 /* Rx: Receiver Buffer Full */



struct stasc_softc {
        device_t sc_dev;
};


static int stasc_match(device_t, cfdata_t, void *);
static void stasc_attach(device_t, device_t, void *);

CFATTACH_DECL_NEW(stasc, sizeof(struct stasc_softc),
    stasc_match, stasc_attach, NULL, NULL);


/* console */
cons_decl(stasc_)

/* assign to cn_tab after cleaning bss to get printf early for the cpu setup */
struct consdev stasc_earlycons = cons_init(stasc_);

extern struct cfdriver stasc_cd;

const struct cdevsw stasc_cdevsw = {
        .d_open = noopen,
        .d_close = noclose,
        .d_read = noread,
        .d_write = nowrite,
        .d_ioctl = noioctl,
        .d_stop = nostop,
        .d_tty = notty,
        .d_poll = nopoll,
        .d_mmap = nommap,
        .d_kqfilter = nokqfilter,
        .d_discard = nodiscard,
        .d_flag = D_TTY
};



static int
stasc_match(device_t parent, cfdata_t cfp, void *aux)
{

        if (strcmp(cfp->cf_name, "stasc") != 0)
                return 0;

        return 0;               /* just stub it out for now */
}


static void
stasc_attach(device_t parent, device_t self, void *aux)
{
        struct stasc_softc *sc;

        sc = device_private(self);
        sc->sc_dev = self;

        aprint_normal("\n");
}


void
stasc_cnprobe(struct consdev *cp)
{

        cp->cn_pri = CN_NORMAL;
}


void
stasc_cninit(struct consdev *cp)
{

        return;
}


int
stasc_cngetc(dev_t dev)
{
        int s = splserial();
        uint32_t status;
        int c;

        /* don't block if Rx buffer is empty */
        status = ASC_INT_STA;
        if (!ISSET(status, ASC_INT_STA_RBF)) {
                splx(s);
                return -1;
        }

        /* can read the character now */
        c = ASC_RX_BUFF;
        splx(s);
        return (unsigned char)c;
}


void
stasc_cnputc(dev_t dev, int c)
{
        int s = splserial();
        uint32_t timo, status;

        /* wait for Tx Full to become clear */
        timo = 150000;
        do {
                status = ASC_INT_STA;
        } while (ISSET(status, ASC_INT_STA_TF) && --timo);

        /* can write the character now */
        ASC_TX_BUFF = c;
        splx(s);
}


void
stasc_cnpollc(dev_t dev, int on)
{

        return;
}