qemu

fdc.c (75097B)

---

 /*
  * 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 "qemu/osdep.h"
 #include "hw/block/fdc.h"
 #include "qapi/error.h"
 #include "qemu/error-report.h"
 #include "qemu/timer.h"
 #include "qemu/memalign.h"
 #include "hw/irq.h"
 #include "hw/isa/isa.h"
 #include "hw/qdev-properties.h"
 #include "hw/qdev-properties-system.h"
 #include "migration/vmstate.h"
 #include "hw/block/block.h"
 #include "sysemu/block-backend.h"
 #include "sysemu/blockdev.h"
 #include "sysemu/sysemu.h"
 #include "qemu/log.h"
 #include "qemu/main-loop.h"
 #include "qemu/module.h"
 #include "trace.h"
 #include "qom/object.h"
 #include "fdc-internal.h"
 
 /********************************************************/
 /* debug Floppy devices */
 
 #define DEBUG_FLOPPY 0
 
 #define FLOPPY_DPRINTF(fmt, ...)                                \
     do {                                                        \
         if (DEBUG_FLOPPY) {                                     \
             fprintf(stderr, "FLOPPY: " fmt , ## __VA_ARGS__);   \
         }                                                       \
     } while (0)
 
 
 /* Anonymous BlockBackend for empty drive */
 static BlockBackend *blk_create_empty_drive(void)
 {
     return blk_new(qemu_get_aio_context(), 0, BLK_PERM_ALL);
 }
 
 /********************************************************/
 /* qdev floppy bus                                      */
 
 #define TYPE_FLOPPY_BUS "floppy-bus"
 OBJECT_DECLARE_SIMPLE_TYPE(FloppyBus, FLOPPY_BUS)
 
 static FDrive *get_drv(FDCtrl *fdctrl, int unit);
 
 static const TypeInfo floppy_bus_info = {
     .name = TYPE_FLOPPY_BUS,
     .parent = TYPE_BUS,
     .instance_size = sizeof(FloppyBus),
 };
 
 static void floppy_bus_create(FDCtrl *fdc, FloppyBus *bus, DeviceState *dev)
 {
     qbus_init(bus, sizeof(FloppyBus), TYPE_FLOPPY_BUS, dev, NULL);
     bus->fdc = fdc;
 }
 
 
 /********************************************************/
 /* Floppy drive emulation                               */
 
 /* In many cases, the total sector size of a format is enough to uniquely
  * identify it. However, there are some total sector collisions between
  * formats of different physical size, and these are noted below by
  * highlighting the total sector size for entries with collisions. */
 const FDFormat fd_formats[] = {
     /* First entry is default format */
     /* 1.44 MB 3"1/2 floppy disks */
     { FLOPPY_DRIVE_TYPE_144, 18, 80, 1, FDRIVE_RATE_500K, }, /* 3.5" 2880 */
     { FLOPPY_DRIVE_TYPE_144, 20, 80, 1, FDRIVE_RATE_500K, }, /* 3.5" 3200 */
     { FLOPPY_DRIVE_TYPE_144, 21, 80, 1, FDRIVE_RATE_500K, },
     { FLOPPY_DRIVE_TYPE_144, 21, 82, 1, FDRIVE_RATE_500K, },
     { FLOPPY_DRIVE_TYPE_144, 21, 83, 1, FDRIVE_RATE_500K, },
     { FLOPPY_DRIVE_TYPE_144, 22, 80, 1, FDRIVE_RATE_500K, },
     { FLOPPY_DRIVE_TYPE_144, 23, 80, 1, FDRIVE_RATE_500K, },
     { FLOPPY_DRIVE_TYPE_144, 24, 80, 1, FDRIVE_RATE_500K, },
     /* 2.88 MB 3"1/2 floppy disks */
     { FLOPPY_DRIVE_TYPE_288, 36, 80, 1, FDRIVE_RATE_1M, },
     { FLOPPY_DRIVE_TYPE_288, 39, 80, 1, FDRIVE_RATE_1M, },
     { FLOPPY_DRIVE_TYPE_288, 40, 80, 1, FDRIVE_RATE_1M, },
     { FLOPPY_DRIVE_TYPE_288, 44, 80, 1, FDRIVE_RATE_1M, },
     { FLOPPY_DRIVE_TYPE_288, 48, 80, 1, FDRIVE_RATE_1M, },
     /* 720 kB 3"1/2 floppy disks */
     { FLOPPY_DRIVE_TYPE_144,  9, 80, 1, FDRIVE_RATE_250K, }, /* 3.5" 1440 */
     { FLOPPY_DRIVE_TYPE_144, 10, 80, 1, FDRIVE_RATE_250K, },
     { FLOPPY_DRIVE_TYPE_144, 10, 82, 1, FDRIVE_RATE_250K, },
     { FLOPPY_DRIVE_TYPE_144, 10, 83, 1, FDRIVE_RATE_250K, },
     { FLOPPY_DRIVE_TYPE_144, 13, 80, 1, FDRIVE_RATE_250K, },
     { FLOPPY_DRIVE_TYPE_144, 14, 80, 1, FDRIVE_RATE_250K, },
     /* 1.2 MB 5"1/4 floppy disks */
     { FLOPPY_DRIVE_TYPE_120, 15, 80, 1, FDRIVE_RATE_500K, },
     { FLOPPY_DRIVE_TYPE_120, 18, 80, 1, FDRIVE_RATE_500K, }, /* 5.25" 2880 */
     { FLOPPY_DRIVE_TYPE_120, 18, 82, 1, FDRIVE_RATE_500K, },
     { FLOPPY_DRIVE_TYPE_120, 18, 83, 1, FDRIVE_RATE_500K, },
     { FLOPPY_DRIVE_TYPE_120, 20, 80, 1, FDRIVE_RATE_500K, }, /* 5.25" 3200 */
     /* 720 kB 5"1/4 floppy disks */
     { FLOPPY_DRIVE_TYPE_120,  9, 80, 1, FDRIVE_RATE_250K, }, /* 5.25" 1440 */
     { FLOPPY_DRIVE_TYPE_120, 11, 80, 1, FDRIVE_RATE_250K, },
     /* 360 kB 5"1/4 floppy disks */
     { FLOPPY_DRIVE_TYPE_120,  9, 40, 1, FDRIVE_RATE_300K, }, /* 5.25" 720 */
     { FLOPPY_DRIVE_TYPE_120,  9, 40, 0, FDRIVE_RATE_300K, },
     { FLOPPY_DRIVE_TYPE_120, 10, 41, 1, FDRIVE_RATE_300K, },
     { FLOPPY_DRIVE_TYPE_120, 10, 42, 1, FDRIVE_RATE_300K, },
     /* 320 kB 5"1/4 floppy disks */
     { FLOPPY_DRIVE_TYPE_120,  8, 40, 1, FDRIVE_RATE_250K, },
     { FLOPPY_DRIVE_TYPE_120,  8, 40, 0, FDRIVE_RATE_250K, },
     /* 360 kB must match 5"1/4 better than 3"1/2... */
     { FLOPPY_DRIVE_TYPE_144,  9, 80, 0, FDRIVE_RATE_250K, }, /* 3.5" 720 */
     /* end */
     { FLOPPY_DRIVE_TYPE_NONE, -1, -1, 0, 0, },
 };
 
 static FDriveSize drive_size(FloppyDriveType drive)
 {
     switch (drive) {
     case FLOPPY_DRIVE_TYPE_120:
         return FDRIVE_SIZE_525;
     case FLOPPY_DRIVE_TYPE_144:
     case FLOPPY_DRIVE_TYPE_288:
         return FDRIVE_SIZE_350;
     default:
         return FDRIVE_SIZE_UNKNOWN;
     }
 }
 
 #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 */
 #define FD_RESET_SENSEI_COUNT  4   /* Number of sense interrupts on RESET */
 
 
 static FloppyDriveType get_fallback_drive_type(FDrive *drv);
 
 /* Hack: FD_SEEK is expected to work on empty drives. However, QEMU
  * currently goes through some pains to keep seeks within the bounds
  * established by last_sect and max_track. Correcting this is difficult,
  * as refactoring FDC code tends to expose nasty bugs in the Linux kernel.
  *
  * For now: allow empty drives to have large bounds so we can seek around,
  * with the understanding that when a diskette is inserted, the bounds will
  * properly tighten to match the geometry of that inserted medium.
  */
 static void fd_empty_seek_hack(FDrive *drv)
 {
     drv->last_sect = 0xFF;
     drv->max_track = 0xFF;
 }
 
 static void fd_init(FDrive *drv)
 {
     /* Drive */
     drv->perpendicular = 0;
     /* Disk */
     drv->disk = FLOPPY_DRIVE_TYPE_NONE;
     drv->last_sect = 0;
     drv->max_track = 0;
     drv->ro = true;
     drv->media_changed = 1;
 }
 
 #define NUM_SIDES(drv) ((drv)->flags & FDISK_DBL_SIDES ? 2 : 1)
 
 static int fd_sector_calc(uint8_t head, uint8_t track, uint8_t sect,
                           uint8_t last_sect, uint8_t num_sides)
 {
     return (((track * num_sides) + head) * last_sect) + sect - 1;
 }
 
 /* Returns current position, in sectors, for given drive */
 static int fd_sector(FDrive *drv)
 {
     return fd_sector_calc(drv->head, drv->track, drv->sect, drv->last_sect,
                           NUM_SIDES(drv));
 }
 
 /* Returns current position, in bytes, for given drive */
 static int fd_offset(FDrive *drv)
 {
     g_assert(fd_sector(drv) < INT_MAX >> BDRV_SECTOR_BITS);
     return fd_sector(drv) << BDRV_SECTOR_BITS;
 }
 
 /* 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 *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_calc(head, track, sect, drv->last_sect, NUM_SIDES(drv));
     ret = 0;
     if (sector != fd_sector(drv)) {
 #if 0
         if (!enable_seek) {
             FLOPPY_DPRINTF("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) {
             if (drv->blk != NULL && blk_is_inserted(drv->blk)) {
                 drv->media_changed = 0;
             }
             ret = 1;
         }
         drv->track = track;
         drv->sect = sect;
     }
 
     if (drv->blk == NULL || !blk_is_inserted(drv->blk)) {
         ret = 2;
     }
 
     return ret;
 }
 
 /* Set drive back to track 0 */
 static void fd_recalibrate(FDrive *drv)
 {
     FLOPPY_DPRINTF("recalibrate\n");
     fd_seek(drv, 0, 0, 1, 1);
 }
 
 /**
  * Determine geometry based on inserted diskette.
  * Will not operate on an empty drive.
  *
  * @return: 0 on success, -1 if the drive is empty.
  */
 static int pick_geometry(FDrive *drv)
 {
     BlockBackend *blk = drv->blk;
     const FDFormat *parse;
     uint64_t nb_sectors, size;
     int i;
     int match, size_match, type_match;
     bool magic = drv->drive == FLOPPY_DRIVE_TYPE_AUTO;
 
     /* We can only pick a geometry if we have a diskette. */
     if (!drv->blk || !blk_is_inserted(drv->blk) ||
         drv->drive == FLOPPY_DRIVE_TYPE_NONE)
     {
         return -1;
     }
 
     /* We need to determine the likely geometry of the inserted medium.
      * In order of preference, we look for:
      * (1) The same drive type and number of sectors,
      * (2) The same diskette size and number of sectors,
      * (3) The same drive type.
      *
      * In all cases, matches that occur higher in the drive table will take
      * precedence over matches that occur later in the table.
      */
     blk_get_geometry(blk, &nb_sectors);
     match = size_match = type_match = -1;
     for (i = 0; ; i++) {
         parse = &fd_formats[i];
         if (parse->drive == FLOPPY_DRIVE_TYPE_NONE) {
             break;
         }
         size = (parse->max_head + 1) * parse->max_track * parse->last_sect;
         if (nb_sectors == size) {
             if (magic || parse->drive == drv->drive) {
                 /* (1) perfect match -- nb_sectors and drive type */
                 goto out;
             } else if (drive_size(parse->drive) == drive_size(drv->drive)) {
                 /* (2) size match -- nb_sectors and physical medium size */
                 match = (match == -1) ? i : match;
             } else {
                 /* This is suspicious -- Did the user misconfigure? */
                 size_match = (size_match == -1) ? i : size_match;
             }
         } else if (type_match == -1) {
             if ((parse->drive == drv->drive) ||
                 (magic && (parse->drive == get_fallback_drive_type(drv)))) {
                 /* (3) type match -- nb_sectors mismatch, but matches the type
                  *     specified explicitly by the user, or matches the fallback
                  *     default type when using the drive autodetect mechanism */
                 type_match = i;
             }
         }
     }
 
     /* No exact match found */
     if (match == -1) {
         if (size_match != -1) {
             parse = &fd_formats[size_match];
             FLOPPY_DPRINTF("User requested floppy drive type '%s', "
                            "but inserted medium appears to be a "
                            "%"PRId64" sector '%s' type\n",
                            FloppyDriveType_str(drv->drive),
                            nb_sectors,
                            FloppyDriveType_str(parse->drive));
         }
         assert(type_match != -1 && "misconfigured fd_format");
         match = type_match;
     }
     parse = &(fd_formats[match]);
 
  out:
     if (parse->max_head == 0) {
         drv->flags &= ~FDISK_DBL_SIDES;
     } else {
         drv->flags |= FDISK_DBL_SIDES;
     }
     drv->max_track = parse->max_track;
     drv->last_sect = parse->last_sect;
     drv->disk = parse->drive;
     drv->media_rate = parse->rate;
     return 0;
 }
 
 static void pick_drive_type(FDrive *drv)
 {
     if (drv->drive != FLOPPY_DRIVE_TYPE_AUTO) {
         return;
     }
 
     if (pick_geometry(drv) == 0) {
         drv->drive = drv->disk;
     } else {
         drv->drive = get_fallback_drive_type(drv);
     }
 
     g_assert(drv->drive != FLOPPY_DRIVE_TYPE_AUTO);
 }
 
 /* Revalidate a disk drive after a disk change */
 static void fd_revalidate(FDrive *drv)
 {
     int rc;
 
     FLOPPY_DPRINTF("revalidate\n");
     if (drv->blk != NULL) {
         drv->ro = !blk_is_writable(drv->blk);
         if (!blk_is_inserted(drv->blk)) {
             FLOPPY_DPRINTF("No disk in drive\n");
             drv->disk = FLOPPY_DRIVE_TYPE_NONE;
             fd_empty_seek_hack(drv);
         } else if (!drv->media_validated) {
             rc = pick_geometry(drv);
             if (rc) {
                 FLOPPY_DPRINTF("Could not validate floppy drive media");
             } else {
                 drv->media_validated = true;
                 FLOPPY_DPRINTF("Floppy disk (%d h %d t %d s) %s\n",
                                (drv->flags & FDISK_DBL_SIDES) ? 2 : 1,
                                drv->max_track, drv->last_sect,
                                drv->ro ? "ro" : "rw");
             }
         }
     } else {
         FLOPPY_DPRINTF("No drive connected\n");
         drv->last_sect = 0;
         drv->max_track = 0;
         drv->flags &= ~FDISK_DBL_SIDES;
         drv->drive = FLOPPY_DRIVE_TYPE_NONE;
         drv->disk = FLOPPY_DRIVE_TYPE_NONE;
     }
 }
 
 static void fd_change_cb(void *opaque, bool load, Error **errp)
 {
     FDrive *drive = opaque;
 
     if (!load) {
         blk_set_perm(drive->blk, 0, BLK_PERM_ALL, &error_abort);
     } else {
         if (!blkconf_apply_backend_options(drive->conf,
                                            !blk_supports_write_perm(drive->blk),
                                            false, errp)) {
             return;
         }
     }
 
     drive->media_changed = 1;
     drive->media_validated = false;
     fd_revalidate(drive);
 }
 
 static const BlockDevOps fd_block_ops = {
     .change_media_cb = fd_change_cb,
 };
 
 
 #define TYPE_FLOPPY_DRIVE "floppy"
 OBJECT_DECLARE_SIMPLE_TYPE(FloppyDrive, FLOPPY_DRIVE)
 
 struct FloppyDrive {
     DeviceState     qdev;
     uint32_t        unit;
     BlockConf       conf;
     FloppyDriveType type;
 };
 
 static Property floppy_drive_properties[] = {
     DEFINE_PROP_UINT32("unit", FloppyDrive, unit, -1),
     DEFINE_BLOCK_PROPERTIES(FloppyDrive, conf),
     DEFINE_PROP_SIGNED("drive-type", FloppyDrive, type,
                         FLOPPY_DRIVE_TYPE_AUTO, qdev_prop_fdc_drive_type,
                         FloppyDriveType),
     DEFINE_PROP_END_OF_LIST(),
 };
 
 static void floppy_drive_realize(DeviceState *qdev, Error **errp)
 {
     FloppyDrive *dev = FLOPPY_DRIVE(qdev);
     FloppyBus *bus = FLOPPY_BUS(qdev->parent_bus);
     FDrive *drive;
     bool read_only;
     int ret;
 
     if (dev->unit == -1) {
         for (dev->unit = 0; dev->unit < MAX_FD; dev->unit++) {
             drive = get_drv(bus->fdc, dev->unit);
             if (!drive->blk) {
                 break;
             }
         }
     }
 
     if (dev->unit >= MAX_FD) {
         error_setg(errp, "Can't create floppy unit %d, bus supports "
                    "only %d units", dev->unit, MAX_FD);
         return;
     }
 
     drive = get_drv(bus->fdc, dev->unit);
     if (drive->blk) {
         error_setg(errp, "Floppy unit %d is in use", dev->unit);
         return;
     }
 
     if (!dev->conf.blk) {
         dev->conf.blk = blk_create_empty_drive();
         ret = blk_attach_dev(dev->conf.blk, qdev);
         assert(ret == 0);
 
         /* Don't take write permissions on an empty drive to allow attaching a
          * read-only node later */
         read_only = true;
     } else {
         read_only = !blk_bs(dev->conf.blk) ||
                     !blk_supports_write_perm(dev->conf.blk);
     }
 
     if (!blkconf_blocksizes(&dev->conf, errp)) {
         return;
     }
 
     if (dev->conf.logical_block_size != 512 ||
         dev->conf.physical_block_size != 512)
     {
         error_setg(errp, "Physical and logical block size must "
                    "be 512 for floppy");
         return;
     }
 
     /* rerror/werror aren't supported by fdc and therefore not even registered
      * with qdev. So set the defaults manually before they are used in
      * blkconf_apply_backend_options(). */
     dev->conf.rerror = BLOCKDEV_ON_ERROR_AUTO;
     dev->conf.werror = BLOCKDEV_ON_ERROR_AUTO;
 
     if (!blkconf_apply_backend_options(&dev->conf, read_only, false, errp)) {
         return;
     }
 
     /* 'enospc' is the default for -drive, 'report' is what blk_new() gives us
      * for empty drives. */
     if (blk_get_on_error(dev->conf.blk, 0) != BLOCKDEV_ON_ERROR_ENOSPC &&
         blk_get_on_error(dev->conf.blk, 0) != BLOCKDEV_ON_ERROR_REPORT) {
         error_setg(errp, "fdc doesn't support drive option werror");
         return;
     }
     if (blk_get_on_error(dev->conf.blk, 1) != BLOCKDEV_ON_ERROR_REPORT) {
         error_setg(errp, "fdc doesn't support drive option rerror");
         return;
     }
 
     drive->conf = &dev->conf;
     drive->blk = dev->conf.blk;
     drive->fdctrl = bus->fdc;
 
     fd_init(drive);
     blk_set_dev_ops(drive->blk, &fd_block_ops, drive);
 
     /* Keep 'type' qdev property and FDrive->drive in sync */
     drive->drive = dev->type;
     pick_drive_type(drive);
     dev->type = drive->drive;
 
     fd_revalidate(drive);
 }
 
 static void floppy_drive_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *k = DEVICE_CLASS(klass);
     k->realize = floppy_drive_realize;
     set_bit(DEVICE_CATEGORY_STORAGE, k->categories);
     k->bus_type = TYPE_FLOPPY_BUS;
     device_class_set_props(k, floppy_drive_properties);
     k->desc = "virtual floppy drive";
 }
 
 static const TypeInfo floppy_drive_info = {
     .name = TYPE_FLOPPY_DRIVE,
     .parent = TYPE_DEVICE,
     .instance_size = sizeof(FloppyDrive),
     .class_init = floppy_drive_class_init,
 };
 
 /********************************************************/
 /* Intel 82078 floppy disk controller emulation          */
 
 static void fdctrl_to_command_phase(FDCtrl *fdctrl);
 static void fdctrl_raise_irq(FDCtrl *fdctrl);
 static FDrive *get_cur_drv(FDCtrl *fdctrl);
 
 static uint32_t fdctrl_read_statusA(FDCtrl *fdctrl);
 static uint32_t fdctrl_read_statusB(FDCtrl *fdctrl);
 static uint32_t fdctrl_read_dor(FDCtrl *fdctrl);
 static void fdctrl_write_dor(FDCtrl *fdctrl, uint32_t value);
 static uint32_t fdctrl_read_tape(FDCtrl *fdctrl);
 static void fdctrl_write_tape(FDCtrl *fdctrl, uint32_t value);
 static uint32_t fdctrl_read_main_status(FDCtrl *fdctrl);
 static void fdctrl_write_rate(FDCtrl *fdctrl, uint32_t value);
 static uint32_t fdctrl_read_data(FDCtrl *fdctrl);
 static void fdctrl_write_data(FDCtrl *fdctrl, uint32_t value);
 static uint32_t fdctrl_read_dir(FDCtrl *fdctrl);
 static void fdctrl_write_ccr(FDCtrl *fdctrl, uint32_t value);
 
 enum {
     FD_DIR_WRITE   = 0,
     FD_DIR_READ    = 1,
     FD_DIR_SCANE   = 2,
     FD_DIR_SCANL   = 3,
     FD_DIR_SCANH   = 4,
     FD_DIR_VERIFY  = 5,
 };
 
 enum {
     FD_STATE_MULTI  = 0x01,	/* multi track flag */
     FD_STATE_FORMAT = 0x02,	/* format 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,
     FD_REG_CCR = 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 = 0x2e,
     FD_CMD_OPTION = 0x33,
     FD_CMD_RESTORE = 0x4e,
     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_DS0      = 0x01,
     FD_SR0_DS1      = 0x02,
     FD_SR0_HEAD     = 0x04,
     FD_SR0_EQPMT    = 0x10,
     FD_SR0_SEEK     = 0x20,
     FD_SR0_ABNTERM  = 0x40,
     FD_SR0_INVCMD   = 0x80,
     FD_SR0_RDYCHG   = 0xc0,
 };
 
 enum {
     FD_SR1_MA       = 0x01, /* Missing address mark */
     FD_SR1_NW       = 0x02, /* Not writable */
     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,
 };
 
 /*
  * See chapter 5.0 "Controller phases" of the spec:
  *
  * Command phase:
  * The host writes a command and its parameters into the FIFO. The command
  * phase is completed when all parameters for the command have been supplied,
  * and execution phase is entered.
  *
  * Execution phase:
  * Data transfers, either DMA or non-DMA. For non-DMA transfers, the FIFO
  * contains the payload now, otherwise it's unused. When all bytes of the
  * required data have been transferred, the state is switched to either result
  * phase (if the command produces status bytes) or directly back into the
  * command phase for the next command.
  *
  * Result phase:
  * The host reads out the FIFO, which contains one or more result bytes now.
  */
 enum {
     /* Only for migration: reconstruct phase from registers like qemu 2.3 */
     FD_PHASE_RECONSTRUCT    = 0,
 
     FD_PHASE_COMMAND        = 1,
     FD_PHASE_EXECUTION      = 2,
     FD_PHASE_RESULT         = 3,
 };
 
 #define FD_MULTI_TRACK(state) ((state) & FD_STATE_MULTI)
 #define FD_FORMAT_CMD(state) ((state) & FD_STATE_FORMAT)
 
 static FloppyDriveType get_fallback_drive_type(FDrive *drv)
 {
     return drv->fdctrl->fallback;
 }
 
 uint32_t fdctrl_read(void *opaque, uint32_t reg)
 {
     FDCtrl *fdctrl = opaque;
     uint32_t retval;
 
     reg &= 7;
     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;
     case FD_REG_MSR:
         retval = fdctrl_read_main_status(fdctrl);
         break;
     case FD_REG_FIFO:
         retval = fdctrl_read_data(fdctrl);
         break;
     case FD_REG_DIR:
         retval = fdctrl_read_dir(fdctrl);
         break;
     default:
         retval = (uint32_t)(-1);
         break;
     }
     trace_fdc_ioport_read(reg, retval);
 
     return retval;
 }
 
 void fdctrl_write(void *opaque, uint32_t reg, uint32_t value)
 {
     FDCtrl *fdctrl = opaque;
 
     reg &= 7;
     trace_fdc_ioport_write(reg, value);
     switch (reg) {
     case FD_REG_DOR:
         fdctrl_write_dor(fdctrl, value);
         break;
     case FD_REG_TDR:
         fdctrl_write_tape(fdctrl, value);
         break;
     case FD_REG_DSR:
         fdctrl_write_rate(fdctrl, value);
         break;
     case FD_REG_FIFO:
         fdctrl_write_data(fdctrl, value);
         break;
     case FD_REG_CCR:
         fdctrl_write_ccr(fdctrl, value);
         break;
     default:
         break;
     }
 }
 
 static bool fdrive_media_changed_needed(void *opaque)
 {
     FDrive *drive = opaque;
 
     return (drive->blk != NULL && drive->media_changed != 1);
 }
 
 static const VMStateDescription vmstate_fdrive_media_changed = {
     .name = "fdrive/media_changed",
     .version_id = 1,
     .minimum_version_id = 1,
     .needed = fdrive_media_changed_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT8(media_changed, FDrive),
         VMSTATE_END_OF_LIST()
     }
 };
 
 static const VMStateDescription vmstate_fdrive_media_rate = {
     .name = "fdrive/media_rate",
     .version_id = 1,
     .minimum_version_id = 1,
     .fields = (VMStateField[]) {
         VMSTATE_UINT8(media_rate, FDrive),
         VMSTATE_END_OF_LIST()
     }
 };
 
 static bool fdrive_perpendicular_needed(void *opaque)
 {
     FDrive *drive = opaque;
 
     return drive->perpendicular != 0;
 }
 
 static const VMStateDescription vmstate_fdrive_perpendicular = {
     .name = "fdrive/perpendicular",
     .version_id = 1,
     .minimum_version_id = 1,
     .needed = fdrive_perpendicular_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT8(perpendicular, FDrive),
         VMSTATE_END_OF_LIST()
     }
 };
 
 static int fdrive_post_load(void *opaque, int version_id)
 {
     fd_revalidate(opaque);
     return 0;
 }
 
 static const VMStateDescription vmstate_fdrive = {
     .name = "fdrive",
     .version_id = 1,
     .minimum_version_id = 1,
     .post_load = fdrive_post_load,
     .fields = (VMStateField[]) {
         VMSTATE_UINT8(head, FDrive),
         VMSTATE_UINT8(track, FDrive),
         VMSTATE_UINT8(sect, FDrive),
         VMSTATE_END_OF_LIST()
     },
     .subsections = (const VMStateDescription*[]) {
         &vmstate_fdrive_media_changed,
         &vmstate_fdrive_media_rate,
         &vmstate_fdrive_perpendicular,
         NULL
     }
 };
 
 /*
  * Reconstructs the phase from register values according to the logic that was
  * implemented in qemu 2.3. This is the default value that is used if the phase
  * subsection is not present on migration.
  *
  * Don't change this function to reflect newer qemu versions, it is part of
  * the migration ABI.
  */
 static int reconstruct_phase(FDCtrl *fdctrl)
 {
     if (fdctrl->msr & FD_MSR_NONDMA) {
         return FD_PHASE_EXECUTION;
     } else if ((fdctrl->msr & FD_MSR_RQM) == 0) {
         /* qemu 2.3 disabled RQM only during DMA transfers */
         return FD_PHASE_EXECUTION;
     } else if (fdctrl->msr & FD_MSR_DIO) {
         return FD_PHASE_RESULT;
     } else {
         return FD_PHASE_COMMAND;
     }
 }
 
 static int fdc_pre_save(void *opaque)
 {
     FDCtrl *s = opaque;
 
     s->dor_vmstate = s->dor | GET_CUR_DRV(s);
 
     return 0;
 }
 
 static int fdc_pre_load(void *opaque)
 {
     FDCtrl *s = opaque;
     s->phase = FD_PHASE_RECONSTRUCT;
     return 0;
 }
 
 static int fdc_post_load(void *opaque, int version_id)
 {
     FDCtrl *s = opaque;
 
     SET_CUR_DRV(s, s->dor_vmstate & FD_DOR_SELMASK);
     s->dor = s->dor_vmstate & ~FD_DOR_SELMASK;
 
     if (s->phase == FD_PHASE_RECONSTRUCT) {
         s->phase = reconstruct_phase(s);
     }
 
     return 0;
 }
 
 static bool fdc_reset_sensei_needed(void *opaque)
 {
     FDCtrl *s = opaque;
 
     return s->reset_sensei != 0;
 }
 
 static const VMStateDescription vmstate_fdc_reset_sensei = {
     .name = "fdc/reset_sensei",
     .version_id = 1,
     .minimum_version_id = 1,
     .needed = fdc_reset_sensei_needed,
     .fields = (VMStateField[]) {
         VMSTATE_INT32(reset_sensei, FDCtrl),
         VMSTATE_END_OF_LIST()
     }
 };
 
 static bool fdc_result_timer_needed(void *opaque)
 {
     FDCtrl *s = opaque;
 
     return timer_pending(s->result_timer);
 }
 
 static const VMStateDescription vmstate_fdc_result_timer = {
     .name = "fdc/result_timer",
     .version_id = 1,
     .minimum_version_id = 1,
     .needed = fdc_result_timer_needed,
     .fields = (VMStateField[]) {
         VMSTATE_TIMER_PTR(result_timer, FDCtrl),
         VMSTATE_END_OF_LIST()
     }
 };
 
 static bool fdc_phase_needed(void *opaque)
 {
     FDCtrl *fdctrl = opaque;
 
     return reconstruct_phase(fdctrl) != fdctrl->phase;
 }
 
 static const VMStateDescription vmstate_fdc_phase = {
     .name = "fdc/phase",
     .version_id = 1,
     .minimum_version_id = 1,
     .needed = fdc_phase_needed,
     .fields = (VMStateField[]) {
         VMSTATE_UINT8(phase, FDCtrl),
         VMSTATE_END_OF_LIST()
     }
 };
 
 const VMStateDescription vmstate_fdc = {
     .name = "fdc",
     .version_id = 2,
     .minimum_version_id = 2,
     .pre_save = fdc_pre_save,
     .pre_load = fdc_pre_load,
     .post_load = fdc_post_load,
     .fields = (VMStateField[]) {
         /* Controller State */
         VMSTATE_UINT8(sra, FDCtrl),
         VMSTATE_UINT8(srb, FDCtrl),
         VMSTATE_UINT8(dor_vmstate, FDCtrl),
         VMSTATE_UINT8(tdr, FDCtrl),
         VMSTATE_UINT8(dsr, FDCtrl),
         VMSTATE_UINT8(msr, FDCtrl),
         VMSTATE_UINT8(status0, FDCtrl),
         VMSTATE_UINT8(status1, FDCtrl),
         VMSTATE_UINT8(status2, FDCtrl),
         /* Command FIFO */
         VMSTATE_VARRAY_INT32(fifo, FDCtrl, fifo_size, 0, vmstate_info_uint8,
                              uint8_t),
         VMSTATE_UINT32(data_pos, FDCtrl),
         VMSTATE_UINT32(data_len, FDCtrl),
         VMSTATE_UINT8(data_state, FDCtrl),
         VMSTATE_UINT8(data_dir, FDCtrl),
         VMSTATE_UINT8(eot, FDCtrl),
         /* States kept only to be returned back */
         VMSTATE_UINT8(timer0, FDCtrl),
         VMSTATE_UINT8(timer1, FDCtrl),
         VMSTATE_UINT8(precomp_trk, FDCtrl),
         VMSTATE_UINT8(config, FDCtrl),
         VMSTATE_UINT8(lock, FDCtrl),
         VMSTATE_UINT8(pwrd, FDCtrl),
         VMSTATE_UINT8_EQUAL(num_floppies, FDCtrl, NULL),
         VMSTATE_STRUCT_ARRAY(drives, FDCtrl, MAX_FD, 1,
                              vmstate_fdrive, FDrive),
         VMSTATE_END_OF_LIST()
     },
     .subsections = (const VMStateDescription*[]) {
         &vmstate_fdc_reset_sensei,
         &vmstate_fdc_result_timer,
         &vmstate_fdc_phase,
         NULL
     }
 };
 
 /* Change IRQ state */
 static void fdctrl_reset_irq(FDCtrl *fdctrl)
 {
     fdctrl->status0 = 0;
     if (!(fdctrl->sra & FD_SRA_INTPEND))
         return;
     FLOPPY_DPRINTF("Reset interrupt\n");
     qemu_set_irq(fdctrl->irq, 0);
     fdctrl->sra &= ~FD_SRA_INTPEND;
 }
 
 static void fdctrl_raise_irq(FDCtrl *fdctrl)
 {
     if (!(fdctrl->sra & FD_SRA_INTPEND)) {
         qemu_set_irq(fdctrl->irq, 1);
         fdctrl->sra |= FD_SRA_INTPEND;
     }
 
     fdctrl->reset_sensei = 0;
     FLOPPY_DPRINTF("Set interrupt status to 0x%02x\n", fdctrl->status0);
 }
 
 /* Reset controller */
 void fdctrl_reset(FDCtrl *fdctrl, int do_irq)
 {
     int i;
 
     FLOPPY_DPRINTF("reset controller\n");
     fdctrl_reset_irq(fdctrl);
     /* Initialise controller */
     fdctrl->sra = 0;
     fdctrl->srb = 0xc0;
     if (!fdctrl->drives[1].blk) {
         fdctrl->sra |= FD_SRA_nDRV2;
     }
     fdctrl->cur_drv = 0;
     fdctrl->dor = FD_DOR_nRESET;
     fdctrl->dor |= (fdctrl->dma_chann != -1) ? FD_DOR_DMAEN : 0;
     fdctrl->msr = FD_MSR_RQM;
     fdctrl->reset_sensei = 0;
     timer_del(fdctrl->result_timer);
     /* FIFO state */
     fdctrl->data_pos = 0;
     fdctrl->data_len = 0;
     fdctrl->data_state = 0;
     fdctrl->data_dir = FD_DIR_WRITE;
     for (i = 0; i < MAX_FD; i++)
         fd_recalibrate(&fdctrl->drives[i]);
     fdctrl_to_command_phase(fdctrl);
     if (do_irq) {
         fdctrl->status0 |= FD_SR0_RDYCHG;
         fdctrl_raise_irq(fdctrl);
         fdctrl->reset_sensei = FD_RESET_SENSEI_COUNT;
     }
 }
 
 static inline FDrive *drv0(FDCtrl *fdctrl)
 {
     return &fdctrl->drives[(fdctrl->tdr & FD_TDR_BOOTSEL) >> 2];
 }
 
 static inline FDrive *drv1(FDCtrl *fdctrl)
 {
     if ((fdctrl->tdr & FD_TDR_BOOTSEL) < (1 << 2))
         return &fdctrl->drives[1];
     else
         return &fdctrl->drives[0];
 }
 
 #if MAX_FD == 4
 static inline FDrive *drv2(FDCtrl *fdctrl)
 {
     if ((fdctrl->tdr & FD_TDR_BOOTSEL) < (2 << 2))
         return &fdctrl->drives[2];
     else
         return &fdctrl->drives[1];
 }
 
 static inline FDrive *drv3(FDCtrl *fdctrl)
 {
     if ((fdctrl->tdr & FD_TDR_BOOTSEL) < (3 << 2))
         return &fdctrl->drives[3];
     else
         return &fdctrl->drives[2];
 }
 #endif
 
 static FDrive *get_drv(FDCtrl *fdctrl, int unit)
 {
     switch (unit) {
         case 0: return drv0(fdctrl);
         case 1: return drv1(fdctrl);
 #if MAX_FD == 4
         case 2: return drv2(fdctrl);
         case 3: return drv3(fdctrl);
 #endif
         default: return NULL;
     }
 }
 
 static FDrive *get_cur_drv(FDCtrl *fdctrl)
 {
     FDrive *cur_drv = get_drv(fdctrl, fdctrl->cur_drv);
 
     if (!cur_drv->blk) {
         /*
          * Kludge: empty drive line selected. Create an anonymous
          * BlockBackend to avoid NULL deref with various BlockBackend
          * API calls within this model (CVE-2021-20196).
          * Due to the controller QOM model limitations, we don't
          * attach the created to the controller device.
          */
         cur_drv->blk = blk_create_empty_drive();
     }
     return cur_drv;
 }
 
 /* Status A register : 0x00 (read-only) */
 static uint32_t fdctrl_read_statusA(FDCtrl *fdctrl)
 {
     uint32_t retval = fdctrl->sra;
 
     FLOPPY_DPRINTF("status register A: 0x%02x\n", retval);
 
     return retval;
 }
 
 /* Status B register : 0x01 (read-only) */
 static uint32_t fdctrl_read_statusB(FDCtrl *fdctrl)
 {
     uint32_t retval = fdctrl->srb;
 
     FLOPPY_DPRINTF("status register B: 0x%02x\n", retval);
 
     return retval;
 }
 
 /* Digital output register : 0x02 */
 static uint32_t fdctrl_read_dor(FDCtrl *fdctrl)
 {
     uint32_t retval = fdctrl->dor;
 
     /* Selected drive */
     retval |= fdctrl->cur_drv;
     FLOPPY_DPRINTF("digital output register: 0x%02x\n", retval);
 
     return retval;
 }
 
 static void fdctrl_write_dor(FDCtrl *fdctrl, uint32_t value)
 {
     FLOPPY_DPRINTF("digital output register set to 0x%02x\n", value);
 
     /* Motors */
     if (value & FD_DOR_MOTEN0)
         fdctrl->srb |= FD_SRB_MTR0;
     else
         fdctrl->srb &= ~FD_SRB_MTR0;
     if (value & FD_DOR_MOTEN1)
         fdctrl->srb |= FD_SRB_MTR1;
     else
         fdctrl->srb &= ~FD_SRB_MTR1;
 
     /* Drive */
     if (value & 1)
         fdctrl->srb |= FD_SRB_DR0;
     else
         fdctrl->srb &= ~FD_SRB_DR0;
 
     /* Reset */
     if (!(value & FD_DOR_nRESET)) {
         if (fdctrl->dor & FD_DOR_nRESET) {
             FLOPPY_DPRINTF("controller enter RESET state\n");
         }
     } else {
         if (!(fdctrl->dor & FD_DOR_nRESET)) {
             FLOPPY_DPRINTF("controller out of RESET state\n");
             fdctrl_reset(fdctrl, 1);
             fdctrl->dsr &= ~FD_DSR_PWRDOWN;
         }
     }
     /* Selected drive */
     fdctrl->cur_drv = value & FD_DOR_SELMASK;
 
     fdctrl->dor = value;
 }
 
 /* Tape drive register : 0x03 */
 static uint32_t fdctrl_read_tape(FDCtrl *fdctrl)
 {
     uint32_t retval = fdctrl->tdr;
 
     FLOPPY_DPRINTF("tape drive register: 0x%02x\n", retval);
 
     return retval;
 }
 
 static void fdctrl_write_tape(FDCtrl *fdctrl, uint32_t value)
 {
     /* Reset mode */
     if (!(fdctrl->dor & FD_DOR_nRESET)) {
         FLOPPY_DPRINTF("Floppy controller in RESET state !\n");
         return;
     }
     FLOPPY_DPRINTF("tape drive register set to 0x%02x\n", value);
     /* Disk boot selection indicator */
     fdctrl->tdr = value & FD_TDR_BOOTSEL;
     /* Tape indicators: never allow */
 }
 
 /* Main status register : 0x04 (read) */
 static uint32_t fdctrl_read_main_status(FDCtrl *fdctrl)
 {
     uint32_t retval = fdctrl->msr;
 
     fdctrl->dsr &= ~FD_DSR_PWRDOWN;
     fdctrl->dor |= FD_DOR_nRESET;
 
     FLOPPY_DPRINTF("main status register: 0x%02x\n", retval);
 
     return retval;
 }
 
 /* Data select rate register : 0x04 (write) */
 static void fdctrl_write_rate(FDCtrl *fdctrl, uint32_t value)
 {
     /* Reset mode */
     if (!(fdctrl->dor & FD_DOR_nRESET)) {
         FLOPPY_DPRINTF("Floppy controller in RESET state !\n");
         return;
     }
     FLOPPY_DPRINTF("select rate register set to 0x%02x\n", value);
     /* Reset: autoclear */
     if (value & FD_DSR_SWRESET) {
         fdctrl->dor &= ~FD_DOR_nRESET;
         fdctrl_reset(fdctrl, 1);
         fdctrl->dor |= FD_DOR_nRESET;
     }
     if (value & FD_DSR_PWRDOWN) {
         fdctrl_reset(fdctrl, 1);
     }
     fdctrl->dsr = value;
 }
 
 /* Configuration control register: 0x07 (write) */
 static void fdctrl_write_ccr(FDCtrl *fdctrl, uint32_t value)
 {
     /* Reset mode */
     if (!(fdctrl->dor & FD_DOR_nRESET)) {
         FLOPPY_DPRINTF("Floppy controller in RESET state !\n");
         return;
     }
     FLOPPY_DPRINTF("configuration control register set to 0x%02x\n", value);
 
     /* Only the rate selection bits used in AT mode, and we
      * store those in the DSR.
      */
     fdctrl->dsr = (fdctrl->dsr & ~FD_DSR_DRATEMASK) |
                   (value & FD_DSR_DRATEMASK);
 }
 
 static int fdctrl_media_changed(FDrive *drv)
 {
     return drv->media_changed;
 }
 
 /* Digital input register : 0x07 (read-only) */
 static uint32_t fdctrl_read_dir(FDCtrl *fdctrl)
 {
     uint32_t retval = 0;
 
     if (fdctrl_media_changed(get_cur_drv(fdctrl))) {
         retval |= FD_DIR_DSKCHG;
     }
     if (retval != 0) {
         FLOPPY_DPRINTF("Floppy digital input register: 0x%02x\n", retval);
     }
 
     return retval;
 }
 
 /* Clear the FIFO and update the state for receiving the next command */
 static void fdctrl_to_command_phase(FDCtrl *fdctrl)
 {
     fdctrl->phase = FD_PHASE_COMMAND;
     fdctrl->data_dir = FD_DIR_WRITE;
     fdctrl->data_pos = 0;
     fdctrl->data_len = 1; /* Accept command byte, adjust for params later */
     fdctrl->msr &= ~(FD_MSR_CMDBUSY | FD_MSR_DIO);
     fdctrl->msr |= FD_MSR_RQM;
 }
 
 /* Update the state to allow the guest to read out the command status.
  * @fifo_len is the number of result bytes to be read out. */
 static void fdctrl_to_result_phase(FDCtrl *fdctrl, int fifo_len)
 {
     fdctrl->phase = FD_PHASE_RESULT;
     fdctrl->data_dir = FD_DIR_READ;
     fdctrl->data_len = fifo_len;
     fdctrl->data_pos = 0;
     fdctrl->msr |= FD_MSR_CMDBUSY | FD_MSR_RQM | FD_MSR_DIO;
 }
 
 /* Set an error: unimplemented/unknown command */
 static void fdctrl_unimplemented(FDCtrl *fdctrl, int direction)
 {
     qemu_log_mask(LOG_UNIMP, "fdc: unimplemented command 0x%02x\n",
                   fdctrl->fifo[0]);
     fdctrl->fifo[0] = FD_SR0_INVCMD;
     fdctrl_to_result_phase(fdctrl, 1);
 }
 
 /* Seek to next sector
  * returns 0 when end of track reached (for DBL_SIDES on head 1)
  * otherwise returns 1
  */
 static int fdctrl_seek_to_next_sect(FDCtrl *fdctrl, FDrive *cur_drv)
 {
     FLOPPY_DPRINTF("seek to next sector (%d %02x %02x => %d)\n",
                    cur_drv->head, cur_drv->track, cur_drv->sect,
                    fd_sector(cur_drv));
     /* XXX: cur_drv->sect >= cur_drv->last_sect should be an
        error in fact */
     uint8_t new_head = cur_drv->head;
     uint8_t new_track = cur_drv->track;
     uint8_t new_sect = cur_drv->sect;
 
     int ret = 1;
 
     if (new_sect >= cur_drv->last_sect ||
         new_sect == fdctrl->eot) {
         new_sect = 1;
         if (FD_MULTI_TRACK(fdctrl->data_state)) {
             if (new_head == 0 &&
                 (cur_drv->flags & FDISK_DBL_SIDES) != 0) {
                 new_head = 1;
             } else {
                 new_head = 0;
                 new_track++;
                 fdctrl->status0 |= FD_SR0_SEEK;
                 if ((cur_drv->flags & FDISK_DBL_SIDES) == 0) {
                     ret = 0;
                 }
             }
         } else {
             fdctrl->status0 |= FD_SR0_SEEK;
             new_track++;
             ret = 0;
         }
         if (ret == 1) {
             FLOPPY_DPRINTF("seek to next track (%d %02x %02x => %d)\n",
                     new_head, new_track, new_sect, fd_sector(cur_drv));
         }
     } else {
         new_sect++;
     }
     fd_seek(cur_drv, new_head, new_track, new_sect, 1);
     return ret;
 }
 
 /* Callback for transfer end (stop or abort) */
 static void fdctrl_stop_transfer(FDCtrl *fdctrl, uint8_t status0,
                                  uint8_t status1, uint8_t status2)
 {
     FDrive *cur_drv;
     cur_drv = get_cur_drv(fdctrl);
 
     fdctrl->status0 &= ~(FD_SR0_DS0 | FD_SR0_DS1 | FD_SR0_HEAD);
     fdctrl->status0 |= GET_CUR_DRV(fdctrl);
     if (cur_drv->head) {
         fdctrl->status0 |= FD_SR0_HEAD;
     }
     fdctrl->status0 |= status0;
 
     FLOPPY_DPRINTF("transfer status: %02x %02x %02x (%02x)\n",
                    status0, status1, status2, fdctrl->status0);
     fdctrl->fifo[0] = fdctrl->status0;
     fdctrl->fifo[1] = status1;
     fdctrl->fifo[2] = status2;
     fdctrl->fifo[3] = cur_drv->track;
     fdctrl->fifo[4] = cur_drv->head;
     fdctrl->fifo[5] = cur_drv->sect;
     fdctrl->fifo[6] = FD_SECTOR_SC;
     fdctrl->data_dir = FD_DIR_READ;
     if (fdctrl->dma_chann != -1 && !(fdctrl->msr & FD_MSR_NONDMA)) {
         IsaDmaClass *k = ISADMA_GET_CLASS(fdctrl->dma);
         k->release_DREQ(fdctrl->dma, fdctrl->dma_chann);
     }
     fdctrl->msr |= FD_MSR_RQM | FD_MSR_DIO;
     fdctrl->msr &= ~FD_MSR_NONDMA;
 
     fdctrl_to_result_phase(fdctrl, 7);
     fdctrl_raise_irq(fdctrl);
 }
 
 /* Prepare a data transfer (either DMA or FIFO) */
 static void fdctrl_start_transfer(FDCtrl *fdctrl, int direction)
 {
     FDrive *cur_drv;
     uint8_t kh, kt, ks;
 
     SET_CUR_DRV(fdctrl, fdctrl->fifo[1] & FD_DOR_SELMASK);
     cur_drv = get_cur_drv(fdctrl);
     kt = fdctrl->fifo[2];
     kh = fdctrl->fifo[3];
     ks = fdctrl->fifo[4];
     FLOPPY_DPRINTF("Start transfer at %d %d %02x %02x (%d)\n",
                    GET_CUR_DRV(fdctrl), kh, kt, ks,
                    fd_sector_calc(kh, kt, ks, cur_drv->last_sect,
                                   NUM_SIDES(cur_drv)));
     switch (fd_seek(cur_drv, kh, kt, ks, fdctrl->config & FD_CONFIG_EIS)) {
     case 2:
         /* sect too big */
         fdctrl_stop_transfer(fdctrl, FD_SR0_ABNTERM, 0x00, 0x00);
         fdctrl->fifo[3] = kt;
         fdctrl->fifo[4] = kh;
         fdctrl->fifo[5] = ks;
         return;
     case 3:
         /* track too big */
         fdctrl_stop_transfer(fdctrl, FD_SR0_ABNTERM, FD_SR1_EC, 0x00);
         fdctrl->fifo[3] = kt;
         fdctrl->fifo[4] = kh;
         fdctrl->fifo[5] = ks;
         return;
     case 4:
         /* No seek enabled */
         fdctrl_stop_transfer(fdctrl, FD_SR0_ABNTERM, 0x00, 0x00);
         fdctrl->fifo[3] = kt;
         fdctrl->fifo[4] = kh;
         fdctrl->fifo[5] = ks;
         return;
     case 1:
         fdctrl->status0 |= FD_SR0_SEEK;
         break;
     default:
         break;
     }
 
     /* Check the data rate. If the programmed data rate does not match
      * the currently inserted medium, the operation has to fail. */
     if ((fdctrl->dsr & FD_DSR_DRATEMASK) != cur_drv->media_rate) {
         FLOPPY_DPRINTF("data rate mismatch (fdc=%d, media=%d)\n",
                        fdctrl->dsr & FD_DSR_DRATEMASK, cur_drv->media_rate);
         fdctrl_stop_transfer(fdctrl, FD_SR0_ABNTERM, FD_SR1_MA, 0x00);
         fdctrl->fifo[3] = kt;
         fdctrl->fifo[4] = kh;
         fdctrl->fifo[5] = ks;
         return;
     }
 
     /* Set the FIFO state */
     fdctrl->data_dir = direction;
     fdctrl->data_pos = 0;
     assert(fdctrl->msr & FD_MSR_CMDBUSY);
     if (fdctrl->fifo[0] & 0x80)
         fdctrl->data_state |= FD_STATE_MULTI;
     else
         fdctrl->data_state &= ~FD_STATE_MULTI;
     if (fdctrl->fifo[5] == 0) {
         fdctrl->data_len = fdctrl->fifo[8];
     } else {
         int tmp;
         fdctrl->data_len = 128 << (fdctrl->fifo[5] > 7 ? 7 : fdctrl->fifo[5]);
         tmp = (fdctrl->fifo[6] - ks + 1);
         if (tmp < 0) {
             FLOPPY_DPRINTF("invalid EOT: %d\n", tmp);
             fdctrl_stop_transfer(fdctrl, FD_SR0_ABNTERM, FD_SR1_MA, 0x00);
             fdctrl->fifo[3] = kt;
             fdctrl->fifo[4] = kh;
             fdctrl->fifo[5] = ks;
             return;
         }
         if (fdctrl->fifo[0] & 0x80)
             tmp += fdctrl->fifo[6];
         fdctrl->data_len *= tmp;
     }
     fdctrl->eot = fdctrl->fifo[6];
     if (fdctrl->dor & FD_DOR_DMAEN) {
         /* DMA transfer is enabled. */
         IsaDmaClass *k = ISADMA_GET_CLASS(fdctrl->dma);
 
         FLOPPY_DPRINTF("direction=%d (%d - %d)\n",
                        direction, (128 << fdctrl->fifo[5]) *
                        (cur_drv->last_sect - ks + 1), fdctrl->data_len);
 
         /* No access is allowed until DMA transfer has completed */
         fdctrl->msr &= ~FD_MSR_RQM;
         if (direction != FD_DIR_VERIFY) {
             /*
              * Now, we just have to wait for the DMA controller to
              * recall us...
              */
             k->hold_DREQ(fdctrl->dma, fdctrl->dma_chann);
             k->schedule(fdctrl->dma);
         } else {
             /* Start transfer */
             fdctrl_transfer_handler(fdctrl, fdctrl->dma_chann, 0,
                     fdctrl->data_len);
         }
         return;
     }
     FLOPPY_DPRINTF("start non-DMA transfer\n");
     fdctrl->msr |= FD_MSR_NONDMA | FD_MSR_RQM;
     if (direction != FD_DIR_WRITE)
         fdctrl->msr |= FD_MSR_DIO;
     /* IO based transfer: calculate len */
     fdctrl_raise_irq(fdctrl);
 }
 
 /* Prepare a transfer of deleted data */
 static void fdctrl_start_transfer_del(FDCtrl *fdctrl, int direction)
 {
     qemu_log_mask(LOG_UNIMP, "fdctrl_start_transfer_del() unimplemented\n");
 
     /* We don't handle deleted data,
      * so we don't return *ANYTHING*
      */
     fdctrl_stop_transfer(fdctrl, FD_SR0_ABNTERM | FD_SR0_SEEK, 0x00, 0x00);
 }
 
 /* handlers for DMA transfers */
 int fdctrl_transfer_handler(void *opaque, int nchan, int dma_pos, int dma_len)
 {
     FDCtrl *fdctrl;
     FDrive *cur_drv;
     int len, start_pos, rel_pos;
     uint8_t status0 = 0x00, status1 = 0x00, status2 = 0x00;
     IsaDmaClass *k;
 
     fdctrl = opaque;
     if (fdctrl->msr & FD_MSR_RQM) {
         FLOPPY_DPRINTF("Not in DMA transfer mode !\n");
         return 0;
     }
     k = ISADMA_GET_CLASS(fdctrl->dma);
     cur_drv = get_cur_drv(fdctrl);
     if (fdctrl->data_dir == FD_DIR_SCANE || fdctrl->data_dir == FD_DIR_SCANL ||
         fdctrl->data_dir == FD_DIR_SCANH)
         status2 = FD_SR2_SNS;
     if (dma_len > fdctrl->data_len)
         dma_len = fdctrl->data_len;
     if (cur_drv->blk == NULL) {
         if (fdctrl->data_dir == FD_DIR_WRITE)
             fdctrl_stop_transfer(fdctrl, FD_SR0_ABNTERM | FD_SR0_SEEK, 0x00, 0x00);
         else
             fdctrl_stop_transfer(fdctrl, FD_SR0_ABNTERM, 0x00, 0x00);
         len = 0;
         goto transfer_error;
     }
     rel_pos = fdctrl->data_pos % FD_SECTOR_LEN;
     for (start_pos = fdctrl->data_pos; fdctrl->data_pos < dma_len;) {
         len = dma_len - fdctrl->data_pos;
         if (len + rel_pos > FD_SECTOR_LEN)
             len = FD_SECTOR_LEN - rel_pos;
         FLOPPY_DPRINTF("copy %d bytes (%d %d %d) %d pos %d %02x "
                        "(%d-0x%08x 0x%08x)\n", len, dma_len, fdctrl->data_pos,
                        fdctrl->data_len, GET_CUR_DRV(fdctrl), cur_drv->head,
                        cur_drv->track, cur_drv->sect, fd_sector(cur_drv),
                        fd_sector(cur_drv) * FD_SECTOR_LEN);
         if (fdctrl->data_dir != FD_DIR_WRITE ||
             len < FD_SECTOR_LEN || rel_pos != 0) {
             /* READ & SCAN commands and realign to a sector for WRITE */
             if (blk_pread(cur_drv->blk, fd_offset(cur_drv), BDRV_SECTOR_SIZE,
                           fdctrl->fifo, 0) < 0) {
                 FLOPPY_DPRINTF("Floppy: error getting sector %d\n",
                                fd_sector(cur_drv));
                 /* Sure, image size is too small... */
                 memset(fdctrl->fifo, 0, FD_SECTOR_LEN);
             }
         }
         switch (fdctrl->data_dir) {
         case FD_DIR_READ:
             /* READ commands */
             k->write_memory(fdctrl->dma, nchan, fdctrl->fifo + rel_pos,
                             fdctrl->data_pos, len);
             break;
         case FD_DIR_WRITE:
             /* WRITE commands */
             if (cur_drv->ro) {
                 /* Handle readonly medium early, no need to do DMA, touch the
                  * LED or attempt any writes. A real floppy doesn't attempt
                  * to write to readonly media either. */
                 fdctrl_stop_transfer(fdctrl,
                                      FD_SR0_ABNTERM | FD_SR0_SEEK, FD_SR1_NW,
                                      0x00);
                 goto transfer_error;
             }
 
             k->read_memory(fdctrl->dma, nchan, fdctrl->fifo + rel_pos,
                            fdctrl->data_pos, len);
             if (blk_pwrite(cur_drv->blk, fd_offset(cur_drv), BDRV_SECTOR_SIZE,
                            fdctrl->fifo, 0) < 0) {
                 FLOPPY_DPRINTF("error writing sector %d\n",
                                fd_sector(cur_drv));
                 fdctrl_stop_transfer(fdctrl, FD_SR0_ABNTERM | FD_SR0_SEEK, 0x00, 0x00);
                 goto transfer_error;
             }
             break;
         case FD_DIR_VERIFY:
             /* VERIFY commands */
             break;
         default:
             /* SCAN commands */
             {
                 uint8_t tmpbuf[FD_SECTOR_LEN];
                 int ret;
                 k->read_memory(fdctrl->dma, nchan, tmpbuf, fdctrl->data_pos,
                                len);
                 ret = memcmp(tmpbuf, fdctrl->fifo + rel_pos, len);
                 if (ret == 0) {
                     status2 = FD_SR2_SEH;
                     goto end_transfer;
                 }
                 if ((ret < 0 && fdctrl->data_dir == FD_DIR_SCANL) ||
                     (ret > 0 && fdctrl->data_dir == FD_DIR_SCANH)) {
                     status2 = 0x00;
                     goto end_transfer;
                 }
             }
             break;
         }
         fdctrl->data_pos += len;
         rel_pos = fdctrl->data_pos % FD_SECTOR_LEN;
         if (rel_pos == 0) {
             /* Seek to next sector */
             if (!fdctrl_seek_to_next_sect(fdctrl, cur_drv))
                 break;
         }
     }
  end_transfer:
     len = fdctrl->data_pos - start_pos;
     FLOPPY_DPRINTF("end transfer %d %d %d\n",
                    fdctrl->data_pos, len, fdctrl->data_len);
     if (fdctrl->data_dir == FD_DIR_SCANE ||
         fdctrl->data_dir == FD_DIR_SCANL ||
         fdctrl->data_dir == FD_DIR_SCANH)
         status2 = FD_SR2_SEH;
     fdctrl->data_len -= len;
     fdctrl_stop_transfer(fdctrl, status0, status1, status2);
  transfer_error:
 
     return len;
 }
 
 /* Data register : 0x05 */
 static uint32_t fdctrl_read_data(FDCtrl *fdctrl)
 {
     FDrive *cur_drv;
     uint32_t retval = 0;
     uint32_t pos;
 
     cur_drv = get_cur_drv(fdctrl);
     fdctrl->dsr &= ~FD_DSR_PWRDOWN;
     if (!(fdctrl->msr & FD_MSR_RQM) || !(fdctrl->msr & FD_MSR_DIO)) {
         FLOPPY_DPRINTF("error: controller not ready for reading\n");
         return 0;
     }
 
     /* If data_len spans multiple sectors, the current position in the FIFO
      * wraps around while fdctrl->data_pos is the real position in the whole
      * request. */
     pos = fdctrl->data_pos;
     pos %= FD_SECTOR_LEN;
 
     switch (fdctrl->phase) {
     case FD_PHASE_EXECUTION:
         assert(fdctrl->msr & FD_MSR_NONDMA);
         if (pos == 0) {
             if (fdctrl->data_pos != 0)
                 if (!fdctrl_seek_to_next_sect(fdctrl, cur_drv)) {
                     FLOPPY_DPRINTF("error seeking to next sector %d\n",
                                    fd_sector(cur_drv));
                     return 0;
                 }
             if (blk_pread(cur_drv->blk, fd_offset(cur_drv), BDRV_SECTOR_SIZE,
                           fdctrl->fifo, 0)
                 < 0) {
                 FLOPPY_DPRINTF("error getting sector %d\n",
                                fd_sector(cur_drv));
                 /* Sure, image size is too small... */
                 memset(fdctrl->fifo, 0, FD_SECTOR_LEN);
             }
         }
 
         if (++fdctrl->data_pos == fdctrl->data_len) {
             fdctrl->msr &= ~FD_MSR_RQM;
             fdctrl_stop_transfer(fdctrl, 0x00, 0x00, 0x00);
         }
         break;
 
     case FD_PHASE_RESULT:
         assert(!(fdctrl->msr & FD_MSR_NONDMA));
         if (++fdctrl->data_pos == fdctrl->data_len) {
             fdctrl->msr &= ~FD_MSR_RQM;
             fdctrl_to_command_phase(fdctrl);
             fdctrl_reset_irq(fdctrl);
         }
         break;
 
     case FD_PHASE_COMMAND:
     default:
         abort();
     }
 
     retval = fdctrl->fifo[pos];
     FLOPPY_DPRINTF("data register: 0x%02x\n", retval);
 
     return retval;
 }
 
 static void fdctrl_format_sector(FDCtrl *fdctrl)
 {
     FDrive *cur_drv;
     uint8_t kh, kt, ks;
 
     SET_CUR_DRV(fdctrl, fdctrl->fifo[1] & FD_DOR_SELMASK);
     cur_drv = get_cur_drv(fdctrl);
     kt = fdctrl->fifo[6];
     kh = fdctrl->fifo[7];
     ks = fdctrl->fifo[8];
     FLOPPY_DPRINTF("format sector at %d %d %02x %02x (%d)\n",
                    GET_CUR_DRV(fdctrl), kh, kt, ks,
                    fd_sector_calc(kh, kt, ks, cur_drv->last_sect,
                                   NUM_SIDES(cur_drv)));
     switch (fd_seek(cur_drv, kh, kt, ks, fdctrl->config & FD_CONFIG_EIS)) {
     case 2:
         /* sect too big */
         fdctrl_stop_transfer(fdctrl, FD_SR0_ABNTERM, 0x00, 0x00);
         fdctrl->fifo[3] = kt;
         fdctrl->fifo[4] = kh;
         fdctrl->fifo[5] = ks;
         return;
     case 3:
         /* track too big */
         fdctrl_stop_transfer(fdctrl, FD_SR0_ABNTERM, FD_SR1_EC, 0x00);
         fdctrl->fifo[3] = kt;
         fdctrl->fifo[4] = kh;
         fdctrl->fifo[5] = ks;
         return;
     case 4:
         /* No seek enabled */
         fdctrl_stop_transfer(fdctrl, FD_SR0_ABNTERM, 0x00, 0x00);
         fdctrl->fifo[3] = kt;
         fdctrl->fifo[4] = kh;
         fdctrl->fifo[5] = ks;
         return;
     case 1:
         fdctrl->status0 |= FD_SR0_SEEK;
         break;
     default:
         break;
     }
     memset(fdctrl->fifo, 0, FD_SECTOR_LEN);
     if (cur_drv->blk == NULL ||
         blk_pwrite(cur_drv->blk, fd_offset(cur_drv), BDRV_SECTOR_SIZE,
                    fdctrl->fifo, 0) < 0) {
         FLOPPY_DPRINTF("error formatting sector %d\n", fd_sector(cur_drv));
         fdctrl_stop_transfer(fdctrl, FD_SR0_ABNTERM | FD_SR0_SEEK, 0x00, 0x00);
     } else {
         if (cur_drv->sect == cur_drv->last_sect) {
             fdctrl->data_state &= ~FD_STATE_FORMAT;
             /* Last sector done */
             fdctrl_stop_transfer(fdctrl, 0x00, 0x00, 0x00);
         } else {
             /* More to do */
             fdctrl->data_pos = 0;
             fdctrl->data_len = 4;
         }
     }
 }
 
 static void fdctrl_handle_lock(FDCtrl *fdctrl, int direction)
 {
     fdctrl->lock = (fdctrl->fifo[0] & 0x80) ? 1 : 0;
     fdctrl->fifo[0] = fdctrl->lock << 4;
     fdctrl_to_result_phase(fdctrl, 1);
 }
 
 static void fdctrl_handle_dumpreg(FDCtrl *fdctrl, int direction)
 {
     FDrive *cur_drv = get_cur_drv(fdctrl);
 
     /* Drives position */
     fdctrl->fifo[0] = drv0(fdctrl)->track;
     fdctrl->fifo[1] = drv1(fdctrl)->track;
 #if MAX_FD == 4
     fdctrl->fifo[2] = drv2(fdctrl)->track;
     fdctrl->fifo[3] = drv3(fdctrl)->track;
 #else
     fdctrl->fifo[2] = 0;
     fdctrl->fifo[3] = 0;
 #endif
     /* timers */
     fdctrl->fifo[4] = fdctrl->timer0;
     fdctrl->fifo[5] = (fdctrl->timer1 << 1) | (fdctrl->dor & FD_DOR_DMAEN ? 1 : 0);
     fdctrl->fifo[6] = cur_drv->last_sect;
     fdctrl->fifo[7] = (fdctrl->lock << 7) |
         (cur_drv->perpendicular << 2);
     fdctrl->fifo[8] = fdctrl->config;
     fdctrl->fifo[9] = fdctrl->precomp_trk;
     fdctrl_to_result_phase(fdctrl, 10);
 }
 
 static void fdctrl_handle_version(FDCtrl *fdctrl, int direction)
 {
     /* Controller's version */
     fdctrl->fifo[0] = fdctrl->version;
     fdctrl_to_result_phase(fdctrl, 1);
 }
 
 static void fdctrl_handle_partid(FDCtrl *fdctrl, int direction)
 {
     fdctrl->fifo[0] = 0x41; /* Stepping 1 */
     fdctrl_to_result_phase(fdctrl, 1);
 }
 
 static void fdctrl_handle_restore(FDCtrl *fdctrl, int direction)
 {
     FDrive *cur_drv = get_cur_drv(fdctrl);
 
     /* Drives position */
     drv0(fdctrl)->track = fdctrl->fifo[3];
     drv1(fdctrl)->track = fdctrl->fifo[4];
 #if MAX_FD == 4
     drv2(fdctrl)->track = fdctrl->fifo[5];
     drv3(fdctrl)->track = fdctrl->fifo[6];
 #endif
     /* timers */
     fdctrl->timer0 = fdctrl->fifo[7];
     fdctrl->timer1 = fdctrl->fifo[8];
     cur_drv->last_sect = fdctrl->fifo[9];
     fdctrl->lock = fdctrl->fifo[10] >> 7;
     cur_drv->perpendicular = (fdctrl->fifo[10] >> 2) & 0xF;
     fdctrl->config = fdctrl->fifo[11];
     fdctrl->precomp_trk = fdctrl->fifo[12];
     fdctrl->pwrd = fdctrl->fifo[13];
     fdctrl_to_command_phase(fdctrl);
 }
 
 static void fdctrl_handle_save(FDCtrl *fdctrl, int direction)
 {
     FDrive *cur_drv = get_cur_drv(fdctrl);
 
     fdctrl->fifo[0] = 0;
     fdctrl->fifo[1] = 0;
     /* Drives position */
     fdctrl->fifo[2] = drv0(fdctrl)->track;
     fdctrl->fifo[3] = drv1(fdctrl)->track;
 #if MAX_FD == 4
     fdctrl->fifo[4] = drv2(fdctrl)->track;
     fdctrl->fifo[5] = drv3(fdctrl)->track;
 #else
     fdctrl->fifo[4] = 0;
     fdctrl->fifo[5] = 0;
 #endif
     /* timers */
     fdctrl->fifo[6] = fdctrl->timer0;
     fdctrl->fifo[7] = fdctrl->timer1;
     fdctrl->fifo[8] = cur_drv->last_sect;
     fdctrl->fifo[9] = (fdctrl->lock << 7) |
         (cur_drv->perpendicular << 2);
     fdctrl->fifo[10] = fdctrl->config;
     fdctrl->fifo[11] = fdctrl->precomp_trk;
     fdctrl->fifo[12] = fdctrl->pwrd;
     fdctrl->fifo[13] = 0;
     fdctrl->fifo[14] = 0;
     fdctrl_to_result_phase(fdctrl, 15);
 }
 
 static void fdctrl_handle_readid(FDCtrl *fdctrl, int direction)
 {
     FDrive *cur_drv = get_cur_drv(fdctrl);
 
     cur_drv->head = (fdctrl->fifo[1] >> 2) & 1;
     timer_mod(fdctrl->result_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
              (NANOSECONDS_PER_SECOND / 50));
 }
 
 static void fdctrl_handle_format_track(FDCtrl *fdctrl, int direction)
 {
     FDrive *cur_drv;
 
     SET_CUR_DRV(fdctrl, fdctrl->fifo[1] & FD_DOR_SELMASK);
     cur_drv = get_cur_drv(fdctrl);
     fdctrl->data_state |= FD_STATE_FORMAT;
     if (fdctrl->fifo[0] & 0x80)
         fdctrl->data_state |= FD_STATE_MULTI;
     else
         fdctrl->data_state &= ~FD_STATE_MULTI;
     cur_drv->bps =
         fdctrl->fifo[2] > 7 ? 16384 : 128 << fdctrl->fifo[2];
 #if 0
     cur_drv->last_sect =
         cur_drv->flags & FDISK_DBL_SIDES ? fdctrl->fifo[3] :
         fdctrl->fifo[3] / 2;
 #else
     cur_drv->last_sect = fdctrl->fifo[3];
 #endif
     /* TODO: implement format using DMA expected by the Bochs BIOS
      * and Linux fdformat (read 3 bytes per sector via DMA and fill
      * the sector with the specified fill byte
      */
     fdctrl->data_state &= ~FD_STATE_FORMAT;
     fdctrl_stop_transfer(fdctrl, 0x00, 0x00, 0x00);
 }
 
 static void fdctrl_handle_specify(FDCtrl *fdctrl, int direction)
 {
     fdctrl->timer0 = (fdctrl->fifo[1] >> 4) & 0xF;
     fdctrl->timer1 = fdctrl->fifo[2] >> 1;
     if (fdctrl->fifo[2] & 1)
         fdctrl->dor &= ~FD_DOR_DMAEN;
     else
         fdctrl->dor |= FD_DOR_DMAEN;
     /* No result back */
     fdctrl_to_command_phase(fdctrl);
 }
 
 static void fdctrl_handle_sense_drive_status(FDCtrl *fdctrl, int direction)
 {
     FDrive *cur_drv;
 
     SET_CUR_DRV(fdctrl, fdctrl->fifo[1] & FD_DOR_SELMASK);
     cur_drv = get_cur_drv(fdctrl);
     cur_drv->head = (fdctrl->fifo[1] >> 2) & 1;
     /* 1 Byte status back */
     fdctrl->fifo[0] = (cur_drv->ro << 6) |
         (cur_drv->track == 0 ? 0x10 : 0x00) |
         (cur_drv->head << 2) |
         GET_CUR_DRV(fdctrl) |
         0x28;
     fdctrl_to_result_phase(fdctrl, 1);
 }
 
 static void fdctrl_handle_recalibrate(FDCtrl *fdctrl, int direction)
 {
     FDrive *cur_drv;
 
     SET_CUR_DRV(fdctrl, fdctrl->fifo[1] & FD_DOR_SELMASK);
     cur_drv = get_cur_drv(fdctrl);
     fd_recalibrate(cur_drv);
     fdctrl_to_command_phase(fdctrl);
     /* Raise Interrupt */
     fdctrl->status0 |= FD_SR0_SEEK;
     fdctrl_raise_irq(fdctrl);
 }
 
 static void fdctrl_handle_sense_interrupt_status(FDCtrl *fdctrl, int direction)
 {
     FDrive *cur_drv = get_cur_drv(fdctrl);
 
     if (fdctrl->reset_sensei > 0) {
         fdctrl->fifo[0] =
             FD_SR0_RDYCHG + FD_RESET_SENSEI_COUNT - fdctrl->reset_sensei;
         fdctrl->reset_sensei--;
     } else if (!(fdctrl->sra & FD_SRA_INTPEND)) {
         fdctrl->fifo[0] = FD_SR0_INVCMD;
         fdctrl_to_result_phase(fdctrl, 1);
         return;
     } else {
         fdctrl->fifo[0] =
                 (fdctrl->status0 & ~(FD_SR0_HEAD | FD_SR0_DS1 | FD_SR0_DS0))
                 | GET_CUR_DRV(fdctrl);
     }
 
     fdctrl->fifo[1] = cur_drv->track;
     fdctrl_to_result_phase(fdctrl, 2);
     fdctrl_reset_irq(fdctrl);
     fdctrl->status0 = FD_SR0_RDYCHG;
 }
 
 static void fdctrl_handle_seek(FDCtrl *fdctrl, int direction)
 {
     FDrive *cur_drv;
 
     SET_CUR_DRV(fdctrl, fdctrl->fifo[1] & FD_DOR_SELMASK);
     cur_drv = get_cur_drv(fdctrl);
     fdctrl_to_command_phase(fdctrl);
     /* The seek command just sends step pulses to the drive and doesn't care if
      * there is a medium inserted of if it's banging the head against the drive.
      */
     fd_seek(cur_drv, cur_drv->head, fdctrl->fifo[2], cur_drv->sect, 1);
     /* Raise Interrupt */
     fdctrl->status0 |= FD_SR0_SEEK;
     fdctrl_raise_irq(fdctrl);
 }
 
 static void fdctrl_handle_perpendicular_mode(FDCtrl *fdctrl, int direction)
 {
     FDrive *cur_drv = get_cur_drv(fdctrl);
 
     if (fdctrl->fifo[1] & 0x80)
         cur_drv->perpendicular = fdctrl->fifo[1] & 0x7;
     /* No result back */
     fdctrl_to_command_phase(fdctrl);
 }
 
 static void fdctrl_handle_configure(FDCtrl *fdctrl, int direction)
 {
     fdctrl->config = fdctrl->fifo[2];
     fdctrl->precomp_trk =  fdctrl->fifo[3];
     /* No result back */
     fdctrl_to_command_phase(fdctrl);
 }
 
 static void fdctrl_handle_powerdown_mode(FDCtrl *fdctrl, int direction)
 {
     fdctrl->pwrd = fdctrl->fifo[1];
     fdctrl->fifo[0] = fdctrl->fifo[1];
     fdctrl_to_result_phase(fdctrl, 1);
 }
 
 static void fdctrl_handle_option(FDCtrl *fdctrl, int direction)
 {
     /* No result back */
     fdctrl_to_command_phase(fdctrl);
 }
 
 static void fdctrl_handle_drive_specification_command(FDCtrl *fdctrl, int direction)
 {
     FDrive *cur_drv = get_cur_drv(fdctrl);
     uint32_t pos;
 
     pos = fdctrl->data_pos - 1;
     pos %= FD_SECTOR_LEN;
     if (fdctrl->fifo[pos] & 0x80) {
         /* Command parameters done */
         if (fdctrl->fifo[pos] & 0x40) {
             fdctrl->fifo[0] = fdctrl->fifo[1];
             fdctrl->fifo[2] = 0;
             fdctrl->fifo[3] = 0;
             fdctrl_to_result_phase(fdctrl, 4);
         } else {
             fdctrl_to_command_phase(fdctrl);
         }
     } else if (fdctrl->data_len > 7) {
         /* ERROR */
         fdctrl->fifo[0] = 0x80 |
             (cur_drv->head << 2) | GET_CUR_DRV(fdctrl);
         fdctrl_to_result_phase(fdctrl, 1);
     }
 }
 
 static void fdctrl_handle_relative_seek_in(FDCtrl *fdctrl, int direction)
 {
     FDrive *cur_drv;
 
     SET_CUR_DRV(fdctrl, fdctrl->fifo[1] & FD_DOR_SELMASK);
     cur_drv = get_cur_drv(fdctrl);
     if (fdctrl->fifo[2] + cur_drv->track >= cur_drv->max_track) {
         fd_seek(cur_drv, cur_drv->head, cur_drv->max_track - 1,
                 cur_drv->sect, 1);
     } else {
         fd_seek(cur_drv, cur_drv->head,
                 cur_drv->track + fdctrl->fifo[2], cur_drv->sect, 1);
     }
     fdctrl_to_command_phase(fdctrl);
     /* Raise Interrupt */
     fdctrl->status0 |= FD_SR0_SEEK;
     fdctrl_raise_irq(fdctrl);
 }
 
 static void fdctrl_handle_relative_seek_out(FDCtrl *fdctrl, int direction)
 {
     FDrive *cur_drv;
 
     SET_CUR_DRV(fdctrl, fdctrl->fifo[1] & FD_DOR_SELMASK);
     cur_drv = get_cur_drv(fdctrl);
     if (fdctrl->fifo[2] > cur_drv->track) {
         fd_seek(cur_drv, cur_drv->head, 0, cur_drv->sect, 1);
     } else {
         fd_seek(cur_drv, cur_drv->head,
                 cur_drv->track - fdctrl->fifo[2], cur_drv->sect, 1);
     }
     fdctrl_to_command_phase(fdctrl);
     /* Raise Interrupt */
     fdctrl->status0 |= FD_SR0_SEEK;
     fdctrl_raise_irq(fdctrl);
 }
 
 /*
  * Handlers for the execution phase of each command
  */
 typedef struct FDCtrlCommand {
     uint8_t value;
     uint8_t mask;
     const char* name;
     int parameters;
     void (*handler)(FDCtrl *fdctrl, int direction);
     int direction;
 } FDCtrlCommand;
 
 static const FDCtrlCommand handlers[] = {
     { FD_CMD_READ, 0x1f, "READ", 8, fdctrl_start_transfer, FD_DIR_READ },
     { FD_CMD_WRITE, 0x3f, "WRITE", 8, fdctrl_start_transfer, FD_DIR_WRITE },
     { FD_CMD_SEEK, 0xff, "SEEK", 2, fdctrl_handle_seek },
     { FD_CMD_SENSE_INTERRUPT_STATUS, 0xff, "SENSE INTERRUPT STATUS", 0, fdctrl_handle_sense_interrupt_status },
     { FD_CMD_RECALIBRATE, 0xff, "RECALIBRATE", 1, fdctrl_handle_recalibrate },
     { FD_CMD_FORMAT_TRACK, 0xbf, "FORMAT TRACK", 5, fdctrl_handle_format_track },
     { FD_CMD_READ_TRACK, 0xbf, "READ TRACK", 8, fdctrl_start_transfer, FD_DIR_READ },
     { FD_CMD_RESTORE, 0xff, "RESTORE", 17, fdctrl_handle_restore }, /* part of READ DELETED DATA */
     { FD_CMD_SAVE, 0xff, "SAVE", 0, fdctrl_handle_save }, /* part of READ DELETED DATA */
     { FD_CMD_READ_DELETED, 0x1f, "READ DELETED DATA", 8, fdctrl_start_transfer_del, FD_DIR_READ },
     { FD_CMD_SCAN_EQUAL, 0x1f, "SCAN EQUAL", 8, fdctrl_start_transfer, FD_DIR_SCANE },
     { FD_CMD_VERIFY, 0x1f, "VERIFY", 8, fdctrl_start_transfer, FD_DIR_VERIFY },
     { FD_CMD_SCAN_LOW_OR_EQUAL, 0x1f, "SCAN LOW OR EQUAL", 8, fdctrl_start_transfer, FD_DIR_SCANL },
     { FD_CMD_SCAN_HIGH_OR_EQUAL, 0x1f, "SCAN HIGH OR EQUAL", 8, fdctrl_start_transfer, FD_DIR_SCANH },
     { FD_CMD_WRITE_DELETED, 0x3f, "WRITE DELETED DATA", 8, fdctrl_start_transfer_del, FD_DIR_WRITE },
     { FD_CMD_READ_ID, 0xbf, "READ ID", 1, fdctrl_handle_readid },
     { FD_CMD_SPECIFY, 0xff, "SPECIFY", 2, fdctrl_handle_specify },
     { FD_CMD_SENSE_DRIVE_STATUS, 0xff, "SENSE DRIVE STATUS", 1, fdctrl_handle_sense_drive_status },
     { FD_CMD_PERPENDICULAR_MODE, 0xff, "PERPENDICULAR MODE", 1, fdctrl_handle_perpendicular_mode },
     { FD_CMD_CONFIGURE, 0xff, "CONFIGURE", 3, fdctrl_handle_configure },
     { FD_CMD_POWERDOWN_MODE, 0xff, "POWERDOWN MODE", 2, fdctrl_handle_powerdown_mode },
     { FD_CMD_OPTION, 0xff, "OPTION", 1, fdctrl_handle_option },
     { FD_CMD_DRIVE_SPECIFICATION_COMMAND, 0xff, "DRIVE SPECIFICATION COMMAND", 5, fdctrl_handle_drive_specification_command },
     { FD_CMD_RELATIVE_SEEK_OUT, 0xff, "RELATIVE SEEK OUT", 2, fdctrl_handle_relative_seek_out },
     { FD_CMD_FORMAT_AND_WRITE, 0xff, "FORMAT AND WRITE", 10, fdctrl_unimplemented },
     { FD_CMD_RELATIVE_SEEK_IN, 0xff, "RELATIVE SEEK IN", 2, fdctrl_handle_relative_seek_in },
     { FD_CMD_LOCK, 0x7f, "LOCK", 0, fdctrl_handle_lock },
     { FD_CMD_DUMPREG, 0xff, "DUMPREG", 0, fdctrl_handle_dumpreg },
     { FD_CMD_VERSION, 0xff, "VERSION", 0, fdctrl_handle_version },
     { FD_CMD_PART_ID, 0xff, "PART ID", 0, fdctrl_handle_partid },
     { FD_CMD_WRITE, 0x1f, "WRITE (BeOS)", 8, fdctrl_start_transfer, FD_DIR_WRITE }, /* not in specification ; BeOS 4.5 bug */
     { 0, 0, "unknown", 0, fdctrl_unimplemented }, /* default handler */
 };
 /* Associate command to an index in the 'handlers' array */
 static uint8_t command_to_handler[256];
 
 static const FDCtrlCommand *get_command(uint8_t cmd)
 {
     int idx;
 
     idx = command_to_handler[cmd];
     FLOPPY_DPRINTF("%s command\n", handlers[idx].name);
     return &handlers[idx];
 }
 
 static void fdctrl_write_data(FDCtrl *fdctrl, uint32_t value)
 {
     FDrive *cur_drv;
     const FDCtrlCommand *cmd;
     uint32_t pos;
 
     /* Reset mode */
     if (!(fdctrl->dor & FD_DOR_nRESET)) {
         FLOPPY_DPRINTF("Floppy controller in RESET state !\n");
         return;
     }
     if (!(fdctrl->msr & FD_MSR_RQM) || (fdctrl->msr & FD_MSR_DIO)) {
         FLOPPY_DPRINTF("error: controller not ready for writing\n");
         return;
     }
     fdctrl->dsr &= ~FD_DSR_PWRDOWN;
 
     FLOPPY_DPRINTF("%s: %02x\n", __func__, value);
 
     /* If data_len spans multiple sectors, the current position in the FIFO
      * wraps around while fdctrl->data_pos is the real position in the whole
      * request. */
     pos = fdctrl->data_pos++;
     pos %= FD_SECTOR_LEN;
     fdctrl->fifo[pos] = value;
 
     if (fdctrl->data_pos == fdctrl->data_len) {
         fdctrl->msr &= ~FD_MSR_RQM;
     }
 
     switch (fdctrl->phase) {
     case FD_PHASE_EXECUTION:
         /* For DMA requests, RQM should be cleared during execution phase, so
          * we would have errored out above. */
         assert(fdctrl->msr & FD_MSR_NONDMA);
 
         /* FIFO data write */
         if (pos == FD_SECTOR_LEN - 1 ||
             fdctrl->data_pos == fdctrl->data_len) {
             cur_drv = get_cur_drv(fdctrl);
             if (blk_pwrite(cur_drv->blk, fd_offset(cur_drv), BDRV_SECTOR_SIZE,
                            fdctrl->fifo, 0) < 0) {
                 FLOPPY_DPRINTF("error writing sector %d\n",
                                fd_sector(cur_drv));
                 break;
             }
             if (!fdctrl_seek_to_next_sect(fdctrl, cur_drv)) {
                 FLOPPY_DPRINTF("error seeking to next sector %d\n",
                                fd_sector(cur_drv));
                 break;
             }
         }
 
         /* Switch to result phase when done with the transfer */
         if (fdctrl->data_pos == fdctrl->data_len) {
             fdctrl_stop_transfer(fdctrl, 0x00, 0x00, 0x00);
         }
         break;
 
     case FD_PHASE_COMMAND:
         assert(!(fdctrl->msr & FD_MSR_NONDMA));
         assert(fdctrl->data_pos < FD_SECTOR_LEN);
 
         if (pos == 0) {
             /* The first byte specifies the command. Now we start reading
              * as many parameters as this command requires. */
             cmd = get_command(value);
             fdctrl->data_len = cmd->parameters + 1;
             if (cmd->parameters) {
                 fdctrl->msr |= FD_MSR_RQM;
             }
             fdctrl->msr |= FD_MSR_CMDBUSY;
         }
 
         if (fdctrl->data_pos == fdctrl->data_len) {
             /* We have all parameters now, execute the command */
             fdctrl->phase = FD_PHASE_EXECUTION;
 
             if (fdctrl->data_state & FD_STATE_FORMAT) {
                 fdctrl_format_sector(fdctrl);
                 break;
             }
 
             cmd = get_command(fdctrl->fifo[0]);
             FLOPPY_DPRINTF("Calling handler for '%s'\n", cmd->name);
             cmd->handler(fdctrl, cmd->direction);
         }
         break;
 
     case FD_PHASE_RESULT:
     default:
         abort();
     }
 }
 
 static void fdctrl_result_timer(void *opaque)
 {
     FDCtrl *fdctrl = opaque;
     FDrive *cur_drv = get_cur_drv(fdctrl);
 
     /* Pretend we are spinning.
      * This is needed for Coherent, which uses READ ID to check for
      * sector interleaving.
      */
     if (cur_drv->last_sect != 0) {
         cur_drv->sect = (cur_drv->sect % cur_drv->last_sect) + 1;
     }
     /* READ_ID can't automatically succeed! */
     if ((fdctrl->dsr & FD_DSR_DRATEMASK) != cur_drv->media_rate) {
         FLOPPY_DPRINTF("read id rate mismatch (fdc=%d, media=%d)\n",
                        fdctrl->dsr & FD_DSR_DRATEMASK, cur_drv->media_rate);
         fdctrl_stop_transfer(fdctrl, FD_SR0_ABNTERM, FD_SR1_MA, 0x00);
     } else {
         fdctrl_stop_transfer(fdctrl, 0x00, 0x00, 0x00);
     }
 }
 
 /* Init functions */
 
 void fdctrl_init_drives(FloppyBus *bus, DriveInfo **fds)
 {
     DeviceState *dev;
     int i;
 
     for (i = 0; i < MAX_FD; i++) {
         if (fds[i]) {
             dev = qdev_new("floppy");
             qdev_prop_set_uint32(dev, "unit", i);
             qdev_prop_set_enum(dev, "drive-type", FLOPPY_DRIVE_TYPE_AUTO);
             qdev_prop_set_drive_err(dev, "drive", blk_by_legacy_dinfo(fds[i]),
                                     &error_fatal);
             qdev_realize_and_unref(dev, &bus->bus, &error_fatal);
         }
     }
 }
 
 void fdctrl_realize_common(DeviceState *dev, FDCtrl *fdctrl, Error **errp)
 {
     int i, j;
     FDrive *drive;
     static int command_tables_inited = 0;
 
     if (fdctrl->fallback == FLOPPY_DRIVE_TYPE_AUTO) {
         error_setg(errp, "Cannot choose a fallback FDrive type of 'auto'");
         return;
     }
 
     /* Fill 'command_to_handler' lookup table */
     if (!command_tables_inited) {
         command_tables_inited = 1;
         for (i = ARRAY_SIZE(handlers) - 1; i >= 0; i--) {
             for (j = 0; j < sizeof(command_to_handler); j++) {
                 if ((j & handlers[i].mask) == handlers[i].value) {
                     command_to_handler[j] = i;
                 }
             }
         }
     }
 
     FLOPPY_DPRINTF("init controller\n");
     fdctrl->fifo = qemu_memalign(512, FD_SECTOR_LEN);
     memset(fdctrl->fifo, 0, FD_SECTOR_LEN);
     fdctrl->fifo_size = 512;
     fdctrl->result_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
                                              fdctrl_result_timer, fdctrl);
 
     fdctrl->version = 0x90; /* Intel 82078 controller */
     fdctrl->config = FD_CONFIG_EIS | FD_CONFIG_EFIFO; /* Implicit seek, polling & FIFO enabled */
     fdctrl->num_floppies = MAX_FD;
 
     floppy_bus_create(fdctrl, &fdctrl->bus, dev);
 
     for (i = 0; i < MAX_FD; i++) {
         drive = &fdctrl->drives[i];
         drive->fdctrl = fdctrl;
         fd_init(drive);
         fd_revalidate(drive);
     }
 }
 
 static void fdc_register_types(void)
 {
     type_register_static(&floppy_bus_info);
     type_register_static(&floppy_drive_info);
 }
 
 type_init(fdc_register_types)