/*

 * QEMU Floppy disk emulator (Intel 82078)

 *

 * Copyright (c) 2003, 2007 Jocelyn Mayer

 * Copyright (c) 2008 Hervé Poussineau

 *

 * 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 "hw.h"

#include "fdc.h"

#include "block.h"

#include "qemu-timer.h"

#include "isa.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                               */

#define GET_CUR_DRV(fdctrl) ((fdctrl)->cur_drv)

#define SET_CUR_DRV(fdctrl, drive) ((fdctrl)->cur_drv = (drive))

/* 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 fdisk_flags_t {

    FDISK_DBL_SIDES  = 0x01,

} fdisk_flags_t;

typedef struct fdrive_t {

    BlockDriverState *bs;

    /* Drive status */

    fdrive_type_t drive;

    uint8_t perpendicular;    /* 2.88 MB access mode    */

    /* Position */

    uint8_t head;

    uint8_t track;

    uint8_t sect;

    /* 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->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);

}

/* Seek to a new position:

 * returns 0 if already on right track

 * returns 1 if track changed

 * returns 2 if track is invalid

 * returns 3 if sector is invalid

 * returns 4 if seek is disabled

 */

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;

}

/* 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 char *str;

} fd_format_t;

static const 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)

{

    const fd_format_t *parse;

    uint64_t nb_sectors, size;

    int i, first_match, match;

    int nb_heads, max_track, last_sect, ro;

    FLOPPY_DPRINTF("revalidate\n");

    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;

    }

}

/********************************************************/

/* 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 status0);

static uint32_t fdctrl_read_statusA (fdctrl_t *fdctrl);

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_DIR_WRITE   = 0,

    FD_DIR_READ    = 1,

    FD_DIR_SCANE   = 2,

    FD_DIR_SCANL   = 3,

    FD_DIR_SCANH   = 4,

};

enum {

    FD_STATE_MULTI  = 0x01,	/* multi track flag */

    FD_STATE_FORMAT = 0x02,	/* format flag */

    FD_STATE_SEEK   = 0x04,	/* seek flag */

};

enum {

    FD_REG_SRA = 0x00,

    FD_REG_SRB = 0x01,

    FD_REG_DOR = 0x02,

    FD_REG_TDR = 0x03,

    FD_REG_MSR = 0x04,

    FD_REG_DSR = 0x04,

    FD_REG_FIFO = 0x05,

    FD_REG_DIR = 0x07,

};

enum {

    FD_CMD_READ_TRACK = 0x02,

    FD_CMD_SPECIFY = 0x03,

    FD_CMD_SENSE_DRIVE_STATUS = 0x04,

    FD_CMD_WRITE = 0x05,

    FD_CMD_READ = 0x06,

    FD_CMD_RECALIBRATE = 0x07,

    FD_CMD_SENSE_INTERRUPT_STATUS = 0x08,

    FD_CMD_WRITE_DELETED = 0x09,

    FD_CMD_READ_ID = 0x0a,

    FD_CMD_READ_DELETED = 0x0c,

    FD_CMD_FORMAT_TRACK = 0x0d,

    FD_CMD_DUMPREG = 0x0e,

    FD_CMD_SEEK = 0x0f,

    FD_CMD_VERSION = 0x10,

    FD_CMD_SCAN_EQUAL = 0x11,

    FD_CMD_PERPENDICULAR_MODE = 0x12,

    FD_CMD_CONFIGURE = 0x13,

    FD_CMD_LOCK = 0x14,

    FD_CMD_VERIFY = 0x16,

    FD_CMD_POWERDOWN_MODE = 0x17,

    FD_CMD_PART_ID = 0x18,

    FD_CMD_SCAN_LOW_OR_EQUAL = 0x19,

    FD_CMD_SCAN_HIGH_OR_EQUAL = 0x1d,

    FD_CMD_SAVE = 0x2c,

    FD_CMD_OPTION = 0x33,

    FD_CMD_RESTORE = 0x4c,

    FD_CMD_DRIVE_SPECIFICATION_COMMAND = 0x8e,

    FD_CMD_RELATIVE_SEEK_OUT = 0x8f,

    FD_CMD_FORMAT_AND_WRITE = 0xcd,

    FD_CMD_RELATIVE_SEEK_IN = 0xcf,

};

enum {

    FD_CONFIG_PRETRK = 0xff, /* Pre-compensation set to track 0 */

    FD_CONFIG_FIFOTHR = 0x0f, /* FIFO threshold set to 1 byte */

    FD_CONFIG_POLL  = 0x10, /* Poll enabled */

    FD_CONFIG_EFIFO = 0x20, /* FIFO disabled */

    FD_CONFIG_EIS   = 0x40, /* No implied seeks */

};

enum {

    FD_SR0_EQPMT    = 0x10,

    FD_SR0_SEEK     = 0x20,

    FD_SR0_ABNTERM  = 0x40,

    FD_SR0_INVCMD   = 0x80,

    FD_SR0_RDYCHG   = 0xc0,

};

enum {

    FD_SR1_EC       = 0x80, /* End of cylinder */

};

enum {

    FD_SR2_SNS      = 0x04, /* Scan not satisfied */

    FD_SR2_SEH      = 0x08, /* Scan equal hit */

};

enum {

    FD_SRA_DIR      = 0x01,

    FD_SRA_nWP      = 0x02,

    FD_SRA_nINDX    = 0x04,

    FD_SRA_HDSEL    = 0x08,

    FD_SRA_nTRK0    = 0x10,

    FD_SRA_STEP     = 0x20,

    FD_SRA_nDRV2    = 0x40,

    FD_SRA_INTPEND  = 0x80,

};

enum {

    FD_SRB_MTR0     = 0x01,

    FD_SRB_MTR1     = 0x02,

    FD_SRB_WGATE    = 0x04,

    FD_SRB_RDATA    = 0x08,

    FD_SRB_WDATA    = 0x10,

    FD_SRB_DR0      = 0x20,

};

enum {

#if MAX_FD == 4

    FD_DOR_SELMASK  = 0x03,

#else

    FD_DOR_SELMASK  = 0x01,

#endif

    FD_DOR_nRESET   = 0x04,

    FD_DOR_DMAEN    = 0x08,

    FD_DOR_MOTEN0   = 0x10,

    FD_DOR_MOTEN1   = 0x20,

    FD_DOR_MOTEN2   = 0x40,

    FD_DOR_MOTEN3   = 0x80,

};

enum {

#if MAX_FD == 4

    FD_TDR_BOOTSEL  = 0x0c,

#else

    FD_TDR_BOOTSEL  = 0x04,

#endif

};

enum {

    FD_DSR_DRATEMASK= 0x03,

    FD_DSR_PWRDOWN  = 0x40,

    FD_DSR_SWRESET  = 0x80,

};

enum {

    FD_MSR_DRV0BUSY = 0x01,

    FD_MSR_DRV1BUSY = 0x02,

    FD_MSR_DRV2BUSY = 0x04,

    FD_MSR_DRV3BUSY = 0x08,

    FD_MSR_CMDBUSY  = 0x10,

    FD_MSR_NONDMA   = 0x20,

    FD_MSR_DIO      = 0x40,

    FD_MSR_RQM      = 0x80,

};

enum {

    FD_DIR_DSKCHG   = 0x80,

};

#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 {

    /* Controller's identification */

    uint8_t version;

    /* HW */

    qemu_irq irq;

    int dma_chann;

    target_phys_addr_t io_base;

    /* Controller state */

    QEMUTimer *result_timer;

    uint8_t sra;

    uint8_t srb;

    uint8_t dor;

    uint8_t tdr;

    uint8_t dsr;

    uint8_t msr;

    uint8_t cur_drv;

    uint8_t status0;

    uint8_t status1;

    uint8_t status2;

    /* Command FIFO */

    uint8_t *fifo;

    uint32_t data_pos;

    uint32_t data_len;

    uint8_t data_state;

    uint8_t data_dir;

    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;

    /* Sun4m quirks? */

    int sun4m;

    /* Floppy drives */

    fdrive_t drives[MAX_FD];

};

static uint32_t fdctrl_read (void *opaque, uint32_t reg)

{

    fdctrl_t *fdctrl = opaque;

    uint32_t retval;

    switch (reg) {

    case FD_REG_SRA:

        retval = fdctrl_read_statusA(fdctrl);

        break;

    case FD_REG_SRB:

        retval = fdctrl_read_statusB(fdctrl);

        break;

    case FD_REG_DOR:

        retval = fdctrl_read_dor(fdctrl);

        break;

    case FD_REG_TDR:

        retval = fdctrl_read_tape(fdctrl);

        break;