fdc.c

qemu虚拟机代码

/*
 * QEMU Floppy disk emulator (Intel 82078)
 * 
 * Copyright (c) 2003 Jocelyn Mayer
 * 
 * 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.
 */
/*
 * The controller is used in Sun4m systems in a slightly different
 * way. There are changes in DOR register and DMA is not available.
 */
#include "vl.h"

/********************************************************/
/* debug Floppy devices */
//#define DEBUG_FLOPPY

#ifdef DEBUG_FLOPPY
#define FLOPPY_DPRINTF(fmt, args...) \
do { printf("FLOPPY: " fmt , ##args); } while (0)
#else
#define FLOPPY_DPRINTF(fmt, args...)
#endif

#define FLOPPY_ERROR(fmt, args...) \
do { printf("FLOPPY ERROR: %s: " fmt, __func__ , ##args); } while (0)

/********************************************************/
/* Floppy drive emulation                               */

/* Will always be a fixed parameter for us */
#define FD_SECTOR_LEN 512
#define FD_SECTOR_SC  2   /* Sector size code */

/* Floppy disk drive emulation */
typedef enum fdisk_type_t {
    FDRIVE_DISK_288   = 0x01, /* 2.88 MB disk           */
    FDRIVE_DISK_144   = 0x02, /* 1.44 MB disk           */
    FDRIVE_DISK_720   = 0x03, /* 720 kB disk            */
    FDRIVE_DISK_USER  = 0x04, /* User defined geometry  */
    FDRIVE_DISK_NONE  = 0x05, /* No disk                */
} fdisk_type_t;

typedef enum fdrive_type_t {
    FDRIVE_DRV_144  = 0x00,   /* 1.44 MB 3"5 drive      */
    FDRIVE_DRV_288  = 0x01,   /* 2.88 MB 3"5 drive      */
    FDRIVE_DRV_120  = 0x02,   /* 1.2  MB 5"25 drive     */
    FDRIVE_DRV_NONE = 0x03,   /* No drive connected     */
} fdrive_type_t;

typedef enum fdrive_flags_t {
    FDRIVE_MOTOR_ON   = 0x01, /* motor on/off           */
    FDRIVE_REVALIDATE = 0x02, /* Revalidated            */
} fdrive_flags_t;

typedef enum fdisk_flags_t {
    FDISK_DBL_SIDES  = 0x01,
} fdisk_flags_t;

typedef struct fdrive_t {
    BlockDriverState *bs;
    /* Drive status */
    fdrive_type_t drive;
    fdrive_flags_t drflags;
    uint8_t perpendicular;    /* 2.88 MB access mode    */
    /* Position */
    uint8_t head;
    uint8_t track;
    uint8_t sect;
    /* Last operation status */
    uint8_t dir;              /* Direction              */
    uint8_t rw;               /* Read/write             */
    /* Media */
    fdisk_flags_t flags;
    uint8_t last_sect;        /* Nb sector per track    */
    uint8_t max_track;        /* Nb of tracks           */
    uint16_t bps;             /* Bytes per sector       */
    uint8_t ro;               /* Is read-only           */
} fdrive_t;

static void fd_init (fdrive_t *drv, BlockDriverState *bs)
{
    /* Drive */
    drv->bs = bs;
    drv->drive = FDRIVE_DRV_NONE;
    drv->drflags = 0;
    drv->perpendicular = 0;
    /* Disk */
    drv->last_sect = 0;
    drv->max_track = 0;
}

static int _fd_sector (uint8_t head, uint8_t track,
                        uint8_t sect, uint8_t last_sect)
{
    return (((track * 2) + head) * last_sect) + sect - 1;
}

/* Returns current position, in sectors, for given drive */
static int fd_sector (fdrive_t *drv)
{
    return _fd_sector(drv->head, drv->track, drv->sect, drv->last_sect);
}

static int fd_seek (fdrive_t *drv, uint8_t head, uint8_t track, uint8_t sect,
                    int enable_seek)
{
    uint32_t sector;
    int ret;

    if (track > drv->max_track ||
	(head != 0 && (drv->flags & FDISK_DBL_SIDES) == 0)) {
        FLOPPY_DPRINTF("try to read %d %02x %02x (max=%d %d %02x %02x)\n",
                       head, track, sect, 1,
                       (drv->flags & FDISK_DBL_SIDES) == 0 ? 0 : 1,
                       drv->max_track, drv->last_sect);
        return 2;
    }
    if (sect > drv->last_sect) {
        FLOPPY_DPRINTF("try to read %d %02x %02x (max=%d %d %02x %02x)\n",
                       head, track, sect, 1,
                       (drv->flags & FDISK_DBL_SIDES) == 0 ? 0 : 1,
                       drv->max_track, drv->last_sect);
        return 3;
    }
    sector = _fd_sector(head, track, sect, drv->last_sect);
    ret = 0;
    if (sector != fd_sector(drv)) {
#if 0
        if (!enable_seek) {
            FLOPPY_ERROR("no implicit seek %d %02x %02x (max=%d %02x %02x)\n",
                         head, track, sect, 1, drv->max_track, drv->last_sect);
            return 4;
        }
#endif
        drv->head = head;
	if (drv->track != track)
	    ret = 1;
        drv->track = track;
        drv->sect = sect;
    }

    return ret;
}

/* Set drive back to track 0 */
static void fd_recalibrate (fdrive_t *drv)
{
    FLOPPY_DPRINTF("recalibrate\n");
    drv->head = 0;
    drv->track = 0;
    drv->sect = 1;
    drv->dir = 1;
    drv->rw = 0;
}

/* Recognize floppy formats */
typedef struct fd_format_t {
    fdrive_type_t drive;
    fdisk_type_t  disk;
    uint8_t last_sect;
    uint8_t max_track;
    uint8_t max_head;
    const unsigned char *str;
} fd_format_t;

static fd_format_t fd_formats[] = {
    /* First entry is default format */
    /* 1.44 MB 3"1/2 floppy disks */
    { FDRIVE_DRV_144, FDRIVE_DISK_144, 18, 80, 1, "1.44 MB 3\"1/2", },
    { FDRIVE_DRV_144, FDRIVE_DISK_144, 20, 80, 1,  "1.6 MB 3\"1/2", },
    { FDRIVE_DRV_144, FDRIVE_DISK_144, 21, 80, 1, "1.68 MB 3\"1/2", },
    { FDRIVE_DRV_144, FDRIVE_DISK_144, 21, 82, 1, "1.72 MB 3\"1/2", },
    { FDRIVE_DRV_144, FDRIVE_DISK_144, 21, 83, 1, "1.74 MB 3\"1/2", },
    { FDRIVE_DRV_144, FDRIVE_DISK_144, 22, 80, 1, "1.76 MB 3\"1/2", },
    { FDRIVE_DRV_144, FDRIVE_DISK_144, 23, 80, 1, "1.84 MB 3\"1/2", },
    { FDRIVE_DRV_144, FDRIVE_DISK_144, 24, 80, 1, "1.92 MB 3\"1/2", },
    /* 2.88 MB 3"1/2 floppy disks */
    { FDRIVE_DRV_288, FDRIVE_DISK_288, 36, 80, 1, "2.88 MB 3\"1/2", },
    { FDRIVE_DRV_288, FDRIVE_DISK_288, 39, 80, 1, "3.12 MB 3\"1/2", },
    { FDRIVE_DRV_288, FDRIVE_DISK_288, 40, 80, 1,  "3.2 MB 3\"1/2", },
    { FDRIVE_DRV_288, FDRIVE_DISK_288, 44, 80, 1, "3.52 MB 3\"1/2", },
    { FDRIVE_DRV_288, FDRIVE_DISK_288, 48, 80, 1, "3.84 MB 3\"1/2", },
    /* 720 kB 3"1/2 floppy disks */
    { FDRIVE_DRV_144, FDRIVE_DISK_720,  9, 80, 1,  "720 kB 3\"1/2", },
    { FDRIVE_DRV_144, FDRIVE_DISK_720, 10, 80, 1,  "800 kB 3\"1/2", },
    { FDRIVE_DRV_144, FDRIVE_DISK_720, 10, 82, 1,  "820 kB 3\"1/2", },
    { FDRIVE_DRV_144, FDRIVE_DISK_720, 10, 83, 1,  "830 kB 3\"1/2", },
    { FDRIVE_DRV_144, FDRIVE_DISK_720, 13, 80, 1, "1.04 MB 3\"1/2", },
    { FDRIVE_DRV_144, FDRIVE_DISK_720, 14, 80, 1, "1.12 MB 3\"1/2", },
    /* 1.2 MB 5"1/4 floppy disks */
    { FDRIVE_DRV_120, FDRIVE_DISK_288, 15, 80, 1,  "1.2 kB 5\"1/4", },
    { FDRIVE_DRV_120, FDRIVE_DISK_288, 18, 80, 1, "1.44 MB 5\"1/4", },
    { FDRIVE_DRV_120, FDRIVE_DISK_288, 18, 82, 1, "1.48 MB 5\"1/4", },
    { FDRIVE_DRV_120, FDRIVE_DISK_288, 18, 83, 1, "1.49 MB 5\"1/4", },
    { FDRIVE_DRV_120, FDRIVE_DISK_288, 20, 80, 1,  "1.6 MB 5\"1/4", },
    /* 720 kB 5"1/4 floppy disks */
    { FDRIVE_DRV_120, FDRIVE_DISK_288,  9, 80, 1,  "720 kB 5\"1/4", },
    { FDRIVE_DRV_120, FDRIVE_DISK_288, 11, 80, 1,  "880 kB 5\"1/4", },
    /* 360 kB 5"1/4 floppy disks */
    { FDRIVE_DRV_120, FDRIVE_DISK_288,  9, 40, 1,  "360 kB 5\"1/4", },
    { FDRIVE_DRV_120, FDRIVE_DISK_288,  9, 40, 0,  "180 kB 5\"1/4", },
    { FDRIVE_DRV_120, FDRIVE_DISK_288, 10, 41, 1,  "410 kB 5\"1/4", },
    { FDRIVE_DRV_120, FDRIVE_DISK_288, 10, 42, 1,  "420 kB 5\"1/4", },
    /* 320 kB 5"1/4 floppy disks */ 
    { FDRIVE_DRV_120, FDRIVE_DISK_288,  8, 40, 1,  "320 kB 5\"1/4", },
    { FDRIVE_DRV_120, FDRIVE_DISK_288,  8, 40, 0,  "160 kB 5\"1/4", },
    /* 360 kB must match 5"1/4 better than 3"1/2... */
    { FDRIVE_DRV_144, FDRIVE_DISK_720,  9, 80, 0,  "360 kB 3\"1/2", },
    /* end */
    { FDRIVE_DRV_NONE, FDRIVE_DISK_NONE, -1, -1, 0, NULL, },
};

/* Revalidate a disk drive after a disk change */
static void fd_revalidate (fdrive_t *drv)
{
    fd_format_t *parse;
    int64_t nb_sectors, size;
    int i, first_match, match;
    int nb_heads, max_track, last_sect, ro;

    FLOPPY_DPRINTF("revalidate\n");
    drv->drflags &= ~FDRIVE_REVALIDATE;
    if (drv->bs != NULL && bdrv_is_inserted(drv->bs)) {
	ro = bdrv_is_read_only(drv->bs);
	bdrv_get_geometry_hint(drv->bs, &nb_heads, &max_track, &last_sect);
	if (nb_heads != 0 && max_track != 0 && last_sect != 0) {
	    FLOPPY_DPRINTF("User defined disk (%d %d %d)",
                           nb_heads - 1, max_track, last_sect);
	} else {
	    bdrv_get_geometry(drv->bs, &nb_sectors);
	    match = -1;
	    first_match = -1;
	    for (i = 0;; i++) {
		parse = &fd_formats[i];
		if (parse->drive == FDRIVE_DRV_NONE)
		    break;
		if (drv->drive == parse->drive ||
		    drv->drive == FDRIVE_DRV_NONE) {
		    size = (parse->max_head + 1) * parse->max_track *
			parse->last_sect;
		    if (nb_sectors == size) {
			match = i;
			break;
		    }
		    if (first_match == -1)
			first_match = i;
		}
	    }
	    if (match == -1) {
		if (first_match == -1)
		    match = 1;
		else
		    match = first_match;
		parse = &fd_formats[match];
	    }
	    nb_heads = parse->max_head + 1;
	    max_track = parse->max_track;
	    last_sect = parse->last_sect;
	    drv->drive = parse->drive;
	    FLOPPY_DPRINTF("%s floppy disk (%d h %d t %d s) %s\n", parse->str,
                           nb_heads, max_track, last_sect, ro ? "ro" : "rw");
	}
	    if (nb_heads == 1) {
		drv->flags &= ~FDISK_DBL_SIDES;
	    } else {
		drv->flags |= FDISK_DBL_SIDES;
	    }
	    drv->max_track = max_track;
	    drv->last_sect = last_sect;
	drv->ro = ro;
    } else {
	FLOPPY_DPRINTF("No disk in drive\n");
        drv->last_sect = 0;
	drv->max_track = 0;
	drv->flags &= ~FDISK_DBL_SIDES;
    }
    drv->drflags |= FDRIVE_REVALIDATE;
}

/* Motor control */
static void fd_start (fdrive_t *drv)
{
    drv->drflags |= FDRIVE_MOTOR_ON;
}

static void fd_stop (fdrive_t *drv)
{
    drv->drflags &= ~FDRIVE_MOTOR_ON;
}

/* Re-initialise a drives (motor off, repositioned) */
static void fd_reset (fdrive_t *drv)
{
    fd_stop(drv);
    fd_recalibrate(drv);
}

/********************************************************/
/* Intel 82078 floppy disk controller emulation          */

static void fdctrl_reset (fdctrl_t *fdctrl, int do_irq);
static void fdctrl_reset_fifo (fdctrl_t *fdctrl);
static int fdctrl_transfer_handler (void *opaque, int nchan,
                                    int dma_pos, int dma_len);
static void fdctrl_raise_irq (fdctrl_t *fdctrl, uint8_t status);
static void fdctrl_result_timer(void *opaque);

static uint32_t fdctrl_read_statusB (fdctrl_t *fdctrl);
static uint32_t fdctrl_read_dor (fdctrl_t *fdctrl);
static void fdctrl_write_dor (fdctrl_t *fdctrl, uint32_t value);
static uint32_t fdctrl_read_tape (fdctrl_t *fdctrl);
static void fdctrl_write_tape (fdctrl_t *fdctrl, uint32_t value);
static uint32_t fdctrl_read_main_status (fdctrl_t *fdctrl);
static void fdctrl_write_rate (fdctrl_t *fdctrl, uint32_t value);
static uint32_t fdctrl_read_data (fdctrl_t *fdctrl);
static void fdctrl_write_data (fdctrl_t *fdctrl, uint32_t value);
static uint32_t fdctrl_read_dir (fdctrl_t *fdctrl);

enum {
    FD_CTRL_ACTIVE = 0x01, /* XXX: suppress that */
    FD_CTRL_RESET  = 0x02,
    FD_CTRL_SLEEP  = 0x04, /* XXX: suppress that */
    FD_CTRL_BUSY   = 0x08, /* dma transfer in progress */
    FD_CTRL_INTR   = 0x10,
};

enum {
    FD_DIR_WRITE   = 0,
    FD_DIR_READ    = 1,
    FD_DIR_SCANE   = 2,
    FD_DIR_SCANL   = 3,
    FD_DIR_SCANH   = 4,
};

enum {
    FD_STATE_CMD    = 0x00,
    FD_STATE_STATUS = 0x01,
    FD_STATE_DATA   = 0x02,
    FD_STATE_STATE  = 0x03,
    FD_STATE_MULTI  = 0x10,
    FD_STATE_SEEK   = 0x20,
    FD_STATE_FORMAT = 0x40,
};

#define FD_STATE(state) ((state) & FD_STATE_STATE)
#define FD_SET_STATE(state, new_state) \
do { (state) = ((state) & ~FD_STATE_STATE) | (new_state); } while (0)
#define FD_MULTI_TRACK(state) ((state) & FD_STATE_MULTI)
#define FD_DID_SEEK(state) ((state) & FD_STATE_SEEK)
#define FD_FORMAT_CMD(state) ((state) & FD_STATE_FORMAT)

struct fdctrl_t {
    fdctrl_t *fdctrl;
    /* Controller's identification */
    uint8_t version;
    /* HW */
    int irq_lvl;
    int dma_chann;
    uint32_t io_base;
    /* Controller state */
    QEMUTimer *result_timer;
    uint8_t state;
    uint8_t dma_en;
    uint8_t cur_drv;
    uint8_t bootsel;
    /* Command FIFO */
    uint8_t fifo[FD_SECTOR_LEN];
    uint32_t data_pos;
    uint32_t data_len;
    uint8_t data_state;
    uint8_t data_dir;
    uint8_t int_status;
    uint8_t eot; /* last wanted sector */
    /* States kept only to be returned back */
    /* Timers state */
    uint8_t timer0;
    uint8_t timer1;
    /* precompensation */
    uint8_t precomp_trk;
    uint8_t config;
    uint8_t lock;
    /* Power down config (also with status regB access mode */
    uint8_t pwrd;
    /* Floppy drives */
    fdrive_t drives[2];
};

static uint32_t fdctrl_read (void *opaque, uint32_t reg)
{
    fdctrl_t *fdctrl = opaque;
    uint32_t retval;

    switch (reg & 0x07) {
#ifdef TARGET_SPARC
    case 0x00:
	// Identify to Linux as S82078B
	retval = fdctrl_read_statusB(fdctrl);
	break;
#endif
    case 0x01:
	retval = fdctrl_read_statusB(fdctrl);
	break;
    case 0x02:
	retval = fdctrl_read_dor(fdctrl);
	break;
    case 0x03:
        retval = fdctrl_read_tape(fdctrl);
	break;
    case 0x04:
        retval = fdctrl_read_main_status(fdctrl);
	break;
    case 0x05:
        retval = fdctrl_read_data(fdctrl);
	break;
    case 0x07:
        retval = fdctrl_read_dir(fdctrl);
	break;
    default:
	retval = (uint32_t)(-1);
	break;
    }
    FLOPPY_DPRINTF("read reg%d: 0x%02x\n", reg & 7, retval);