Archipelago » qemu

/*

 * QEMU DMA emulation

 * 

 * Copyright (c) 2003 Vassili Karpov (malc)

 * 

 * 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 <stdio.h>

#include <stdlib.h>

#include <inttypes.h>

#include "cpu.h"

#include "vl.h"

#define log(...) fprintf (stderr, "dma: " __VA_ARGS__)

#ifdef DEBUG_DMA

#define lwarn(...) fprintf (stderr, "dma: " __VA_ARGS__)

#define linfo(...) fprintf (stderr, "dma: " __VA_ARGS__)

#define ldebug(...) fprintf (stderr, "dma: " __VA_ARGS__)

#else

#define lwarn(...)

#define linfo(...)

#define ldebug(...)

#endif

#define MEM_REAL(addr) ((addr)+(uint32_t)(phys_ram_base))

#define LENOFA(a) ((int) (sizeof(a)/sizeof(a[0])))

struct dma_regs {

    int now[2];

    uint16_t base[2];

    uint8_t mode;

    uint8_t page;

    uint8_t dack;

    uint8_t eop;

    DMA_read_handler read_handler;

    DMA_misc_handler misc_handler;

};

#define ADDR 0

#define COUNT 1

static struct dma_cont {

    uint8_t status;

    uint8_t command;

    uint8_t mask;

    uint8_t flip_flop;

    struct dma_regs regs[4];

} dma_controllers[2];

enum {

  CMD_MEMORY_TO_MEMORY = 0x01,

  CMD_FIXED_ADDRESS    = 0x02,

  CMD_BLOCK_CONTROLLER = 0x04,

  CMD_COMPRESSED_TIME  = 0x08,

  CMD_CYCLIC_PRIORITY  = 0x10,

  CMD_EXTENDED_WRITE   = 0x20,

  CMD_LOW_DREQ         = 0x40,

  CMD_LOW_DACK         = 0x80,

  CMD_NOT_SUPPORTED    = CMD_MEMORY_TO_MEMORY | CMD_FIXED_ADDRESS

  | CMD_COMPRESSED_TIME | CMD_CYCLIC_PRIORITY | CMD_EXTENDED_WRITE

  | CMD_LOW_DREQ | CMD_LOW_DACK

};

static void write_page (CPUState *env, uint32_t nport, uint32_t data)

{

    int ichan;

    int ncont;

    static int channels[8] = {-1, 2, 3, 1, -1, -1, -1, 0};

    ncont = nport > 0x87;

    ichan = channels[nport - 0x80 - (ncont << 3)];

    if (-1 == ichan) {

        log ("invalid channel %#x %#x\n", nport, data);

        return;

    }

    dma_controllers[ncont].regs[ichan].page = data;

}

static void init_chan (int ncont, int ichan)

{

    struct dma_regs *r;

    r = dma_controllers[ncont].regs + ichan;

    r->now[ADDR] = r->base[0] << ncont;

    r->now[COUNT] = 0;

}

static inline int getff (int ncont)

{

    int ff;

    ff = dma_controllers[ncont].flip_flop;

    dma_controllers[ncont].flip_flop = !ff;

    return ff;

}

static uint32_t read_chan (CPUState *env, uint32_t nport)

{

    int ff;

    int ncont, ichan, nreg;

    struct dma_regs *r;

    int val;

    ncont = nport > 7;

    ichan = (nport >> (1 + ncont)) & 3;

    nreg = (nport >> ncont) & 1;

    r = dma_controllers[ncont].regs + ichan;

    ff = getff (ncont);

    if (nreg)

        val = (r->base[COUNT] << ncont) - r->now[COUNT];

    else

        val = r->now[ADDR] + r->now[COUNT];

    return (val >> (ncont + (ff << 3))) & 0xff;

}

static void write_chan (CPUState *env, uint32_t nport, uint32_t data)

{

    int ncont, ichan, nreg;

    struct dma_regs *r;

    ncont = nport > 7;

    ichan = (nport >> (1 + ncont)) & 3;

    nreg = (nport >> ncont) & 1;

    r = dma_controllers[ncont].regs + ichan;

    if (getff (ncont)) {

        r->base[nreg] = (r->base[nreg] & 0xff) | ((data << 8) & 0xff00);

        init_chan (ncont, ichan);

    } else {

        r->base[nreg] = (r->base[nreg] & 0xff00) | (data & 0xff);

    }

}

static void write_cont (CPUState *env, uint32_t nport, uint32_t data)

{

    int iport, ichan, ncont;

    struct dma_cont *d;

    ncont = nport > 0xf;

    ichan = -1;

    d = dma_controllers + ncont;

    if (ncont) {

        iport = ((nport - 0xd0) >> 1) + 8;

    }

    else {

        iport = nport;

    }

    switch (iport) {

    case 8:                     /* command */

        if (data && (data | CMD_NOT_SUPPORTED)) {

            log ("command %#x not supported\n", data);

            goto error;

        }

        d->command = data;

        break;

    case 9:

        ichan = data & 3;

        if (data & 4) {

            d->status |= 1 << (ichan + 4);

        }

        else {

            d->status &= ~(1 << (ichan + 4));

        }

        d->status &= ~(1 << ichan);

        break;

    case 0xa:                   /* single mask */

        if (data & 4)

            d->mask |= 1 << (data & 3);

        else

            d->mask &= ~(1 << (data & 3));

        break;

    case 0xb:                   /* mode */

        {

            ichan = data & 3;

#ifdef DEBUG_DMA

            int op;

            int ai;

            int dir;

            int opmode;

            op = (data >> 2) & 3;

            ai = (data >> 4) & 1;

            dir = (data >> 5) & 1;

            opmode = (data >> 6) & 3;

            linfo ("ichan %d, op %d, ai %d, dir %d, opmode %d\n",

                   ichan, op, ai, dir, opmode);

#endif

            d->regs[ichan].mode = data;

            break;

        }

    case 0xc:                   /* clear flip flop */

        d->flip_flop = 0;

        break;

    case 0xd:                   /* reset */

        d->flip_flop = 0;

        d->mask = ~0;

        d->status = 0;

        d->command = 0;

        break;

    case 0xe:                   /* clear mask for all channels */

        d->mask = 0;

        break;

    case 0xf:                   /* write mask for all channels */

        d->mask = data;

        break;

    default:

        log ("dma: unknown iport %#x\n", iport);

        goto error;

    }

#ifdef DEBUG_DMA

    if (0xc != iport) {

        linfo ("nport %#06x, ncont %d, ichan % 2d, val %#06x\n",

               nport, d != dma_controllers, ichan, data);

    }

#endif

    return;

 error:

    abort ();

}

int DMA_get_channel_mode (int nchan)

{

    return dma_controllers[nchan > 3].regs[nchan & 3].mode;

}

void DMA_hold_DREQ (int nchan)

{

    int ncont, ichan;

    ncont = nchan > 3;

    ichan = nchan & 3;

    linfo ("held cont=%d chan=%d\n", ncont, ichan);

    dma_controllers[ncont].status |= 1 << (ichan + 4);

}

void DMA_release_DREQ (int nchan)

{

    int ncont, ichan;

    ncont = nchan > 3;

    ichan = nchan & 3;

    linfo ("released cont=%d chan=%d\n", ncont, ichan);

    dma_controllers[ncont].status &= ~(1 << (ichan + 4));

}

static void channel_run (int ncont, int ichan)

{

    struct dma_regs *r;

    int n;

    int irq;

    uint32_t addr;

/*     int ai, dir; */

    r = dma_controllers[ncont].regs + ichan;

/*   ai = r->mode & 16; */

/*   dir = r->mode & 32 ? -1 : 1; */

    addr = MEM_REAL ((r->page << 16) | r->now[ADDR]);

    irq = -1;

    n = r->read_handler (addr, (r->base[COUNT] << ncont) + (1 << ncont), &irq);

    r->now[COUNT] = n;

    ldebug ("dma_pos %d irq %d size %d\n",

            n, irq, (r->base[1] << ncont) + (1 << ncont));

    if (-1 != irq) {

        pic_set_irq (irq, 1);

    }

}

void DMA_run (void)

{

    static int in_dma;

    struct dma_cont *d;

    int icont, ichan;

    if (in_dma) {

        log ("attempt to re-enter dma\n");

        return;

    }

    in_dma = 1;

    d = dma_controllers;

    for (icont = 0; icont < 2; icont++, d++) {

        for (ichan = 0; ichan < 4; ichan++) {

            int mask;

            mask = 1 << ichan;

            if ((0 == (d->mask & mask)) && (0 != (d->status & (mask << 4))))

                channel_run (icont, ichan);

        }

    }

    in_dma = 0;

}

void DMA_register_channel (int nchan,

                           DMA_read_handler read_handler,

                           DMA_misc_handler misc_handler)

{

    struct dma_regs *r;

    int ichan, ncont;

    ncont = nchan > 3;

    ichan = nchan & 3;

    r = dma_controllers[ncont].regs + ichan;

    r->read_handler = read_handler;

    r->misc_handler = misc_handler;

}

void DMA_init (void)

{

    int i;

    int page_port_list[] = { 0x1, 0x2, 0x3, 0x7 };

    for (i = 0; i < 8; i++) {

        register_ioport_write (i, 1, write_chan, 1);

        register_ioport_write (0xc0 + (i << 1), 1, write_chan, 1);

        register_ioport_read (i, 1, read_chan, 1);

        register_ioport_read (0xc0 + (i << 1), 1, read_chan, 1);

    }

    for (i = 0; i < LENOFA (page_port_list); i++) {

        register_ioport_write (page_port_list[i] + 0x80, 1, write_page, 1);

        register_ioport_write (page_port_list[i] + 0x88, 1, write_page, 1);

    }

    for (i = 0; i < 8; i++) {

        register_ioport_write (i + 8, 1, write_cont, 1);

        register_ioport_write (0xd0 + (i << 1), 1, write_cont, 1);

    }

    write_cont (NULL, 0x0d, 0);

    write_cont (NULL, 0xda, 0);

}