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/*

 * QEMU SCI/SCIF serial port emulation

 *

 * Copyright (c) 2007 Magnus Damm

 *

 * Based on serial.c - QEMU 16450 UART emulation

 * Copyright (c) 2003-2004 Fabrice Bellard

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#include "hw.h"

#include "sh.h"

#include "qemu-char.h"

#include <assert.h>

//#define DEBUG_SERIAL

#define SH_SERIAL_FLAG_TEND (1 << 0)

#define SH_SERIAL_FLAG_TDE  (1 << 1)

#define SH_SERIAL_FLAG_RDF  (1 << 2)

#define SH_SERIAL_FLAG_BRK  (1 << 3)

#define SH_SERIAL_FLAG_DR   (1 << 4)

#define SH_RX_FIFO_LENGTH (16)

typedef struct {

    uint8_t smr;

    uint8_t brr;

    uint8_t scr;

    uint8_t dr; /* ftdr / tdr */

    uint8_t sr; /* fsr / ssr */

    uint16_t fcr;

    uint8_t sptr;

    uint8_t rx_fifo[SH_RX_FIFO_LENGTH]; /* frdr / rdr */

    uint8_t rx_cnt;

    uint8_t rx_tail;

    uint8_t rx_head;

    target_phys_addr_t base;

    int freq;

    int feat;

    int flags;

    int rtrg;

    CharDriverState *chr;

    struct intc_source *eri;

    struct intc_source *rxi;

    struct intc_source *txi;

    struct intc_source *tei;

    struct intc_source *bri;

} sh_serial_state;

static void sh_serial_clear_fifo(sh_serial_state * s)

{

    memset(s->rx_fifo, 0, SH_RX_FIFO_LENGTH);

    s->rx_cnt = 0;

    s->rx_head = 0;

    s->rx_tail = 0;

}

static void sh_serial_ioport_write(void *opaque, uint32_t offs, uint32_t val)

{

    sh_serial_state *s = opaque;

    unsigned char ch;

#ifdef DEBUG_SERIAL

    printf("sh_serial: write base=0x%08lx offs=0x%02x val=0x%02x\n",

           (unsigned long) s->base, offs, val);

#endif

    switch(offs) {

    case 0x00: /* SMR */

        s->smr = val & ((s->feat & SH_SERIAL_FEAT_SCIF) ? 0x7b : 0xff);

        return;

    case 0x04: /* BRR */

        s->brr = val;

        return;

    case 0x08: /* SCR */

        /* TODO : For SH7751, SCIF mask should be 0xfb. */

        s->scr = val & ((s->feat & SH_SERIAL_FEAT_SCIF) ? 0xfa : 0xff);

        if (!(val & (1 << 5)))

            s->flags |= SH_SERIAL_FLAG_TEND;

        if ((s->feat & SH_SERIAL_FEAT_SCIF) && s->txi) {

            if ((val & (1 << 7)) && !(s->txi->asserted))

                sh_intc_toggle_source(s->txi, 0, 1);

            else if (!(val & (1 << 7)) && s->txi->asserted)

                sh_intc_toggle_source(s->txi, 0, -1);

        }

        if (!(val & (1 << 6)) && s->rxi->asserted) {

            sh_intc_toggle_source(s->rxi, 0, -1);

        }

        return;

    case 0x0c: /* FTDR / TDR */

        if (s->chr) {

            ch = val;

            qemu_chr_write(s->chr, &ch, 1);

        }

        s->dr = val;

        s->flags &= ~SH_SERIAL_FLAG_TDE;

        return;

#if 0

    case 0x14: /* FRDR / RDR */

        ret = 0;

        break;

#endif

    }

    if (s->feat & SH_SERIAL_FEAT_SCIF) {

        switch(offs) {

        case 0x10: /* FSR */

            if (!(val & (1 << 6)))

                s->flags &= ~SH_SERIAL_FLAG_TEND;

            if (!(val & (1 << 5)))

                s->flags &= ~SH_SERIAL_FLAG_TDE;

            if (!(val & (1 << 4)))

                s->flags &= ~SH_SERIAL_FLAG_BRK;

            if (!(val & (1 << 1)))

                s->flags &= ~SH_SERIAL_FLAG_RDF;

            if (!(val & (1 << 0)))

                s->flags &= ~SH_SERIAL_FLAG_DR;

            if (!(val & (1 << 1)) || !(val & (1 << 0))) {

                if (s->rxi && s->rxi->asserted) {

                    sh_intc_toggle_source(s->rxi, 0, -1);

                }

            }

            return;

        case 0x18: /* FCR */

            s->fcr = val;

            switch ((val >> 6) & 3) {

            case 0:

                s->rtrg = 1;

                break;

            case 1:

                s->rtrg = 4;

                break;

            case 2:

                s->rtrg = 8;

                break;

            case 3:

                s->rtrg = 14;

                break;

            }

            if (val & (1 << 1)) {

                sh_serial_clear_fifo(s);

                s->sr &= ~(1 << 1);

            }

            return;

        case 0x20: /* SPTR */

            s->sptr = val & 0xf3;

            return;

        case 0x24: /* LSR */

            return;

        }

    }

    else {

#if 0

        switch(offs) {

        case 0x0c:

            ret = s->dr;

            break;

        case 0x10:

            ret = 0;

            break;

        case 0x1c:

            ret = s->sptr;

            break;

        }

#endif

    }

    fprintf(stderr, "sh_serial: unsupported write to 0x%02x\n", offs);

    assert(0);

}

static uint32_t sh_serial_ioport_read(void *opaque, uint32_t offs)

{

    sh_serial_state *s = opaque;

    uint32_t ret = ~0;

#if 0

    switch(offs) {

    case 0x00:

        ret = s->smr;

        break;

    case 0x04:

        ret = s->brr;

        break;

    case 0x08:

        ret = s->scr;

        break;

    case 0x14:

        ret = 0;

        break;

    }

#endif

    if (s->feat & SH_SERIAL_FEAT_SCIF) {

        switch(offs) {

        case 0x00: /* SMR */

            ret = s->smr;

            break;

        case 0x08: /* SCR */

            ret = s->scr;

            break;

        case 0x10: /* FSR */

            ret = 0;

            if (s->flags & SH_SERIAL_FLAG_TEND)

                ret |= (1 << 6);

            if (s->flags & SH_SERIAL_FLAG_TDE)

                ret |= (1 << 5);

            if (s->flags & SH_SERIAL_FLAG_BRK)

                ret |= (1 << 4);

            if (s->flags & SH_SERIAL_FLAG_RDF)

                ret |= (1 << 1);

            if (s->flags & SH_SERIAL_FLAG_DR)

                ret |= (1 << 0);

            if (s->scr & (1 << 5))

                s->flags |= SH_SERIAL_FLAG_TDE | SH_SERIAL_FLAG_TEND;

            break;

        case 0x14:

            if (s->rx_cnt > 0) {

                ret = s->rx_fifo[s->rx_tail++];

                s->rx_cnt--;

                if (s->rx_tail == SH_RX_FIFO_LENGTH)

                    s->rx_tail = 0;

                if (s->rx_cnt < s->rtrg)

                    s->flags &= ~SH_SERIAL_FLAG_RDF;

            }

            break;

#if 0

        case 0x18:

            ret = s->fcr;

            break;

#endif

        case 0x1c:

            ret = s->rx_cnt;

            break;

        case 0x20:

            ret = s->sptr;

            break;

        case 0x24:

            ret = 0;

            break;

        }

    }

    else {

#if 0

        switch(offs) {

        case 0x0c:

            ret = s->dr;

            break;

        case 0x10:

            ret = 0;

            break;

        case 0x14:

            ret = s->rx_fifo[0];

            break;

        case 0x1c:

            ret = s->sptr;

            break;

        }

#endif

    }

#ifdef DEBUG_SERIAL

    printf("sh_serial: read base=0x%08lx offs=0x%02x val=0x%x\n",

           (unsigned long) s->base, offs, ret);

#endif

    if (ret & ~((1 << 16) - 1)) {

        fprintf(stderr, "sh_serial: unsupported read from 0x%02x\n", offs);

        assert(0);

    }

    return ret;

}

static int sh_serial_can_receive(sh_serial_state *s)

{

    return s->scr & (1 << 4);

}

static void sh_serial_receive_byte(sh_serial_state *s, int ch)

{

    if (s->feat & SH_SERIAL_FEAT_SCIF) {

        if (s->rx_cnt < SH_RX_FIFO_LENGTH) {

            s->rx_fifo[s->rx_head++] = ch;

            if (s->rx_head == SH_RX_FIFO_LENGTH)

                s->rx_head = 0;

            s->rx_cnt++;

            if (s->rx_cnt >= s->rtrg) {

                s->flags |= SH_SERIAL_FLAG_RDF;

                if (s->scr & (1 << 6) && s->rxi) {

                    sh_intc_toggle_source(s->rxi, 0, 1);

                }

            }

        }

    } else {

        s->rx_fifo[0] = ch;

    }

}

static void sh_serial_receive_break(sh_serial_state *s)

{

    if (s->feat & SH_SERIAL_FEAT_SCIF)

        s->sr |= (1 << 4);

}

static int sh_serial_can_receive1(void *opaque)

{

    sh_serial_state *s = opaque;

    return sh_serial_can_receive(s);

}

static void sh_serial_receive1(void *opaque, const uint8_t *buf, int size)

{

    sh_serial_state *s = opaque;

    sh_serial_receive_byte(s, buf[0]);

}

static void sh_serial_event(void *opaque, int event)

{

    sh_serial_state *s = opaque;

    if (event == CHR_EVENT_BREAK)

        sh_serial_receive_break(s);

}

static uint32_t sh_serial_read (void *opaque, target_phys_addr_t addr)

{

    sh_serial_state *s = opaque;

    return sh_serial_ioport_read(s, addr - s->base);

}

static void sh_serial_write (void *opaque,

                             target_phys_addr_t addr, uint32_t value)

{

    sh_serial_state *s = opaque;

    sh_serial_ioport_write(s, addr - s->base, value);

}

static CPUReadMemoryFunc *sh_serial_readfn[] = {

    &sh_serial_read,

    &sh_serial_read,

    &sh_serial_read,

};

static CPUWriteMemoryFunc *sh_serial_writefn[] = {

    &sh_serial_write,

    &sh_serial_write,

    &sh_serial_write,

};

void sh_serial_init (target_phys_addr_t base, int feat,

                     uint32_t freq, CharDriverState *chr,

                     struct intc_source *eri_source,

                     struct intc_source *rxi_source,

                     struct intc_source *txi_source,

                     struct intc_source *tei_source,

                     struct intc_source *bri_source)

{

    sh_serial_state *s;

    int s_io_memory;

    s = qemu_mallocz(sizeof(sh_serial_state));

    if (!s)

        return;

    s->base = base;

    s->feat = feat;

    s->flags = SH_SERIAL_FLAG_TEND | SH_SERIAL_FLAG_TDE;

    s->rtrg = 1;

    s->smr = 0;

    s->brr = 0xff;

    s->scr = 1 << 5; /* pretend that TX is enabled so early printk works */

    s->sptr = 0;

    if (feat & SH_SERIAL_FEAT_SCIF) {

        s->fcr = 0;

    }

    else {

        s->dr = 0xff;

    }

    sh_serial_clear_fifo(s);

    s_io_memory = cpu_register_io_memory(0, sh_serial_readfn,

                                         sh_serial_writefn, s);

    cpu_register_physical_memory(base, 0x28, s_io_memory);

    s->chr = chr;

    if (chr)

        qemu_chr_add_handlers(chr, sh_serial_can_receive1, sh_serial_receive1,

                              sh_serial_event, s);

    s->eri = eri_source;

    s->rxi = rxi_source;

    s->txi = txi_source;

    s->tei = tei_source;

    s->bri = bri_source;

}