swim3.c

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/*
 * Driver for the SWIM3 (Super Woz Integrated Machine 3)
 * floppy controller found on Power Macintoshes.
 *
 * Copyright (C) 1996 Paul Mackerras.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

/*
 * TODO:
 * handle 2 drives
 * handle GCR disks
 */

#undef DEBUG

#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/delay.h>
#include <linux/fd.h>
#include <linux/ioctl.h>
#include <linux/blkdev.h>
#include <linux/interrupt.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <asm/io.h>
#include <asm/dbdma.h>
#include <asm/prom.h>
#include <asm/uaccess.h>
#include <asm/mediabay.h>
#include <asm/machdep.h>
#include <asm/pmac_feature.h>

#define MAX_FLOPPIES    2

static DEFINE_MUTEX(swim3_mutex);
static struct gendisk *disks[MAX_FLOPPIES];

enum swim_state {
    idle,
    locating,
    seeking,
    settling,
    do_transfer,
    jogging,
    available,
    revalidating,
    ejecting
};

#define REG(x)  unsigned char x; char x ## _pad[15];

/*
 * The names for these registers mostly represent speculation on my part.
 * It will be interesting to see how close they are to the names Apple uses.
 */
struct swim3 {
    REG(data);
    REG(timer);     /* counts down at 1MHz */
    REG(error);
    REG(mode);
    REG(select);        /* controls CA0, CA1, CA2 and LSTRB signals */
    REG(setup);
    REG(control);       /* writing bits clears them */
    REG(status);        /* writing bits sets them in control */
    REG(intr);
    REG(nseek);     /* # tracks to seek */
    REG(ctrack);        /* current track number */
    REG(csect);     /* current sector number */
    REG(gap3);      /* size of gap 3 in track format */
    REG(sector);        /* sector # to read or write */
    REG(nsect);     /* # sectors to read or write */
    REG(intr_enable);
};

#define control_bic control
#define control_bis status

/* Bits in select register */
#define CA_MASK     7
#define LSTRB       8

/* Bits in control register */
#define DO_SEEK     0x80
#define FORMAT      0x40
#define SELECT      0x20
#define WRITE_SECTORS   0x10
#define DO_ACTION   0x08
#define DRIVE2_ENABLE   0x04
#define DRIVE_ENABLE    0x02
#define INTR_ENABLE 0x01

/* Bits in status register */
#define FIFO_1BYTE  0x80
#define FIFO_2BYTE  0x40
#define ERROR       0x20
#define DATA        0x08
#define RDDATA      0x04
#define INTR_PENDING    0x02
#define MARK_BYTE   0x01

/* Bits in intr and intr_enable registers */
#define ERROR_INTR  0x20
#define DATA_CHANGED    0x10
#define TRANSFER_DONE   0x08
#define SEEN_SECTOR 0x04
#define SEEK_DONE   0x02
#define TIMER_DONE  0x01

/* Bits in error register */
#define ERR_DATA_CRC    0x80
#define ERR_ADDR_CRC    0x40
#define ERR_OVERRUN 0x04
#define ERR_UNDERRUN    0x01

/* Bits in setup register */
#define S_SW_RESET  0x80
#define S_GCR_WRITE 0x40
#define S_IBM_DRIVE 0x20
#define S_TEST_MODE 0x10
#define S_FCLK_DIV2 0x08
#define S_GCR       0x04
#define S_COPY_PROT 0x02
#define S_INV_WDATA 0x01

/* Select values for swim3_action */
#define SEEK_POSITIVE   0
#define SEEK_NEGATIVE   4
#define STEP        1
#define MOTOR_ON    2
#define MOTOR_OFF   6
#define INDEX       3
#define EJECT       7
#define SETMFM      9
#define SETGCR      13

/* Select values for swim3_select and swim3_readbit */
#define STEP_DIR    0
#define STEPPING    1
#define MOTOR_ON    2
#define RELAX       3   /* also eject in progress */
#define READ_DATA_0 4
#define TWOMEG_DRIVE    5
#define SINGLE_SIDED    6   /* drive or diskette is 4MB type? */
#define DRIVE_PRESENT   7
#define DISK_IN     8
#define WRITE_PROT  9
#define TRACK_ZERO  10
#define TACHO       11
#define READ_DATA_1 12
#define MFM_MODE    13
#define SEEK_COMPLETE   14
#define ONEMEG_MEDIA    15

/* Definitions of values used in writing and formatting */
#define DATA_ESCAPE 0x99
#define GCR_SYNC_EXC    0x3f
#define GCR_SYNC_CONV   0x80
#define GCR_FIRST_MARK  0xd5
#define GCR_SECOND_MARK 0xaa
#define GCR_ADDR_MARK   "\xd5\xaa\x00"
#define GCR_DATA_MARK   "\xd5\xaa\x0b"
#define GCR_SLIP_BYTE   "\x27\xaa"
#define GCR_SELF_SYNC   "\x3f\xbf\x1e\x34\x3c\x3f"

#define DATA_99     "\x99\x99"
#define MFM_ADDR_MARK   "\x99\xa1\x99\xa1\x99\xa1\x99\xfe"
#define MFM_INDEX_MARK  "\x99\xc2\x99\xc2\x99\xc2\x99\xfc"
#define MFM_GAP_LEN 12

struct floppy_state {
    enum swim_state state;
    struct swim3 __iomem *swim3;    /* hardware registers */
    struct dbdma_regs __iomem *dma; /* DMA controller registers */
    int swim3_intr; /* interrupt number for SWIM3 */
    int dma_intr;   /* interrupt number for DMA channel */
    int cur_cyl;    /* cylinder head is on, or -1 */
    int cur_sector; /* last sector we saw go past */
    int req_cyl;    /* the cylinder for the current r/w request */
    int head;       /* head number ditto */
    int req_sector; /* sector number ditto */
    int scount;     /* # sectors we're transferring at present */
    int retries;
    int settle_time;
    int secpercyl;  /* disk geometry information */
    int secpertrack;
    int total_secs;
    int write_prot; /* 1 if write-protected, 0 if not, -1 dunno */
    struct dbdma_cmd *dma_cmd;
    int ref_count;
    int expect_cyl;
    struct timer_list timeout;
    int timeout_pending;
    int ejected;
    wait_queue_head_t wait;
    int wanted;
    struct macio_dev *mdev;
    char    dbdma_cmd_space[5 * sizeof(struct dbdma_cmd)];
    int index;
    struct request *cur_req;
};

#define swim3_err(fmt, arg...)  dev_err(&fs->mdev->ofdev.dev, "[fd%d] " fmt, fs->index, arg)
#define swim3_warn(fmt, arg...) dev_warn(&fs->mdev->ofdev.dev, "[fd%d] " fmt, fs->index, arg)
#define swim3_info(fmt, arg...) dev_info(&fs->mdev->ofdev.dev, "[fd%d] " fmt, fs->index, arg)

#ifdef DEBUG
#define swim3_dbg(fmt, arg...)  dev_dbg(&fs->mdev->ofdev.dev, "[fd%d] " fmt, fs->index, arg)
#else
#define swim3_dbg(fmt, arg...)  do { } while(0)
#endif

static struct floppy_state floppy_states[MAX_FLOPPIES];
static int floppy_count = 0;
static DEFINE_SPINLOCK(swim3_lock);

static unsigned short write_preamble[] = {
    0x4e4e, 0x4e4e, 0x4e4e, 0x4e4e, 0x4e4e, /* gap field */
    0, 0, 0, 0, 0, 0,           /* sync field */
    0x99a1, 0x99a1, 0x99a1, 0x99fb,     /* data address mark */
    0x990f                  /* no escape for 512 bytes */
};

static unsigned short write_postamble[] = {
    0x9904,                 /* insert CRC */
    0x4e4e, 0x4e4e,
    0x9908,                 /* stop writing */
    0, 0, 0, 0, 0, 0
};

static void seek_track(struct floppy_state *fs, int n);
static void init_dma(struct dbdma_cmd *cp, int cmd, void *buf, int count);
static void act(struct floppy_state *fs);
static void scan_timeout(unsigned long data);
static void seek_timeout(unsigned long data);
static void settle_timeout(unsigned long data);
static void xfer_timeout(unsigned long data);
static irqreturn_t swim3_interrupt(int irq, void *dev_id);
/*static void fd_dma_interrupt(int irq, void *dev_id);*/
static int grab_drive(struct floppy_state *fs, enum swim_state state,
              int interruptible);
static void release_drive(struct floppy_state *fs);
static int fd_eject(struct floppy_state *fs);
static int floppy_ioctl(struct block_device *bdev, fmode_t mode,
            unsigned int cmd, unsigned long param);
static int floppy_open(struct block_device *bdev, fmode_t mode);
static int floppy_release(struct gendisk *disk, fmode_t mode);
static unsigned int floppy_check_events(struct gendisk *disk,
                    unsigned int clearing);
static int floppy_revalidate(struct gendisk *disk);

static bool swim3_end_request(struct floppy_state *fs, int err, unsigned int nr_bytes)
{
    struct request *req = fs->cur_req;
    int rc;

    swim3_dbg("  end request, err=%d nr_bytes=%d, cur_req=%p\n",
          err, nr_bytes, req);

    if (err)
        nr_bytes = blk_rq_cur_bytes(req);
    rc = __blk_end_request(req, err, nr_bytes);
    if (rc)
        return true;
    fs->cur_req = NULL;
    return false;
}

static void swim3_select(struct floppy_state *fs, int sel)
{
    struct swim3 __iomem *sw = fs->swim3;

    out_8(&sw->select, RELAX);
    if (sel & 8)
        out_8(&sw->control_bis, SELECT);
    else
        out_8(&sw->control_bic, SELECT);
    out_8(&sw->select, sel & CA_MASK);
}

static void swim3_action(struct floppy_state *fs, int action)
{
    struct swim3 __iomem *sw = fs->swim3;

    swim3_select(fs, action);
    udelay(1);
    out_8(&sw->select, sw->select | LSTRB);
    udelay(2);
    out_8(&sw->select, sw->select & ~LSTRB);
    udelay(1);
}

static int swim3_readbit(struct floppy_state *fs, int bit)
{
    struct swim3 __iomem *sw = fs->swim3;
    int stat;

    swim3_select(fs, bit);
    udelay(1);
    stat = in_8(&sw->status);
    return (stat & DATA) == 0;
}

static void start_request(struct floppy_state *fs)
{
    struct request *req;
    unsigned long x;

    swim3_dbg("start request, initial state=%d\n", fs->state);

    if (fs->state == idle && fs->wanted) {
        fs->state = available;
        wake_up(&fs->wait);
        return;
    }
    while (fs->state == idle) {
        swim3_dbg("start request, idle loop, cur_req=%p\n", fs->cur_req);
        if (!fs->cur_req) {
            fs->cur_req = blk_fetch_request(disks[fs->index]->queue);
            swim3_dbg("  fetched request %p\n", fs->cur_req);
            if (!fs->cur_req)
                break;
        }
        req = fs->cur_req;

        if (fs->mdev->media_bay &&
            check_media_bay(fs->mdev->media_bay) != MB_FD) {
            swim3_dbg("%s", "  media bay absent, dropping req\n");
            swim3_end_request(fs, -ENODEV, 0);
            continue;
        }

#if 0 /* This is really too verbose */
        swim3_dbg("do_fd_req: dev=%s cmd=%d sec=%ld nr_sec=%u buf=%p\n",
              req->rq_disk->disk_name, req->cmd,
              (long)blk_rq_pos(req), blk_rq_sectors(req),
              req->buffer);
        swim3_dbg("           errors=%d current_nr_sectors=%u\n",
              req->errors, blk_rq_cur_sectors(req));
#endif

        if (blk_rq_pos(req) >= fs->total_secs) {
            swim3_dbg("  pos out of bounds (%ld, max is %ld)\n",
                  (long)blk_rq_pos(req), (long)fs->total_secs);
            swim3_end_request(fs, -EIO, 0);
            continue;
        }
        if (fs->ejected) {
            swim3_dbg("%s", "  disk ejected\n");
            swim3_end_request(fs, -EIO, 0);
            continue;
        }

        if (rq_data_dir(req) == WRITE) {
            if (fs->write_prot < 0)
                fs->write_prot = swim3_readbit(fs, WRITE_PROT);
            if (fs->write_prot) {
                swim3_dbg("%s", "  try to write, disk write protected\n");
                swim3_end_request(fs, -EIO, 0);
                continue;
            }
        }

        /* Do not remove the cast. blk_rq_pos(req) is now a
         * sector_t and can be 64 bits, but it will never go
         * past 32 bits for this driver anyway, so we can
         * safely cast it down and not have to do a 64/32
         * division
         */
        fs->req_cyl = ((long)blk_rq_pos(req)) / fs->secpercyl;
        x = ((long)blk_rq_pos(req)) % fs->secpercyl;
        fs->head = x / fs->secpertrack;
        fs->req_sector = x % fs->secpertrack + 1;
        fs->state = do_transfer;
        fs->retries = 0;

        act(fs);
    }
}

static void do_fd_request(struct request_queue * q)
{
    start_request(q->queuedata);
}

static void set_timeout(struct floppy_state *fs, int nticks,
            void (*proc)(unsigned long))
{
    if (fs->timeout_pending)
        del_timer(&fs->timeout);
    fs->timeout.expires = jiffies + nticks;
    fs->timeout.function = proc;
    fs->timeout.data = (unsigned long) fs;
    add_timer(&fs->timeout);
    fs->timeout_pending = 1;
}

static inline void scan_track(struct floppy_state *fs)
{
    struct swim3 __iomem *sw = fs->swim3;

    swim3_select(fs, READ_DATA_0);
    in_8(&sw->intr);        /* clear SEEN_SECTOR bit */
    in_8(&sw->error);
    out_8(&sw->intr_enable, SEEN_SECTOR);
    out_8(&sw->control_bis, DO_ACTION);
    /* enable intr when track found */
    set_timeout(fs, HZ, scan_timeout);  /* enable timeout */
}

static inline void seek_track(struct floppy_state *fs, int n)
{
    struct swim3 __iomem *sw = fs->swim3;

    if (n >= 0) {
        swim3_action(fs, SEEK_POSITIVE);
        sw->nseek = n;
    } else {
        swim3_action(fs, SEEK_NEGATIVE);
        sw->nseek = -n;
    }
    fs->expect_cyl = (fs->cur_cyl >= 0)? fs->cur_cyl + n: -1;
    swim3_select(fs, STEP);
    in_8(&sw->error);
    /* enable intr when seek finished */
    out_8(&sw->intr_enable, SEEK_DONE);
    out_8(&sw->control_bis, DO_SEEK);
    set_timeout(fs, 3*HZ, seek_timeout);    /* enable timeout */
    fs->settle_time = 0;
}

static inline void init_dma(struct dbdma_cmd *cp, int cmd,
                void *buf, int count)
{
    st_le16(&cp->req_count, count);
    st_le16(&cp->command, cmd);
    st_le32(&cp->phy_addr, virt_to_bus(buf));
    cp->xfer_status = 0;
}

static inline void setup_transfer(struct floppy_state *fs)
{
    int n;
    struct swim3 __iomem *sw = fs->swim3;
    struct dbdma_cmd *cp = fs->dma_cmd;
    struct dbdma_regs __iomem *dr = fs->dma;
    struct request *req = fs->cur_req;

    if (blk_rq_cur_sectors(req) <= 0) {
        swim3_warn("%s", "Transfer 0 sectors ?\n");
        return;
    }
    if (rq_data_dir(req) == WRITE)
        n = 1;
    else {
        n = fs->secpertrack - fs->req_sector + 1;
        if (n > blk_rq_cur_sectors(req))
            n = blk_rq_cur_sectors(req);
    }

    swim3_dbg("  setup xfer at sect %d (of %d) head %d for %d\n",
          fs->req_sector, fs->secpertrack, fs->head, n);

    fs->scount = n;
    swim3_select(fs, fs->head? READ_DATA_1: READ_DATA_0);
    out_8(&sw->sector, fs->req_sector);
    out_8(&sw->nsect, n);
    out_8(&sw->gap3, 0);
    out_le32(&dr->cmdptr, virt_to_bus(cp));
    if (rq_data_dir(req) == WRITE) {
        /* Set up 3 dma commands: write preamble, data, postamble */
        init_dma(cp, OUTPUT_MORE, write_preamble, sizeof(write_preamble));
        ++cp;
        init_dma(cp, OUTPUT_MORE, req->buffer, 512);
        ++cp;
        init_dma(cp, OUTPUT_LAST, write_postamble, sizeof(write_postamble));
    } else {
        init_dma(cp, INPUT_LAST, req->buffer, n * 512);
    }
    ++cp;
    out_le16(&cp->command, DBDMA_STOP);
    out_8(&sw->control_bic, DO_ACTION | WRITE_SECTORS);
    in_8(&sw->error);
    out_8(&sw->control_bic, DO_ACTION | WRITE_SECTORS);
    if (rq_data_dir(req) == WRITE)
        out_8(&sw->control_bis, WRITE_SECTORS);
    in_8(&sw->intr);
    out_le32(&dr->control, (RUN << 16) | RUN);
    /* enable intr when transfer complete */
    out_8(&sw->intr_enable, TRANSFER_DONE);
    out_8(&sw->control_bis, DO_ACTION);
    set_timeout(fs, 2*HZ, xfer_timeout);    /* enable timeout */
}

static void act(struct floppy_state *fs)
{
    for (;;) {
        swim3_dbg("  act loop, state=%d, req_cyl=%d, cur_cyl=%d\n",
              fs->state, fs->req_cyl, fs->cur_cyl);

        switch (fs->state) {
        case idle:
            return;     /* XXX shouldn't get here */

        case locating:
            if (swim3_readbit(fs, TRACK_ZERO)) {
                swim3_dbg("%s", "    locate track 0\n");
                fs->cur_cyl = 0;
                if (fs->req_cyl == 0)
                    fs->state = do_transfer;
                else
                    fs->state = seeking;
                break;
            }
            scan_track(fs);
            return;

        case seeking:
            if (fs->cur_cyl < 0) {
                fs->expect_cyl = -1;
                fs->state = locating;
                break;
            }
            if (fs->req_cyl == fs->cur_cyl) {
                swim3_warn("%s", "Whoops, seeking 0\n");
                fs->state = do_transfer;
                break;
            }
            seek_track(fs, fs->req_cyl - fs->cur_cyl);
            return;

        case settling:
            /* check for SEEK_COMPLETE after 30ms */
            fs->settle_time = (HZ + 32) / 33;
            set_timeout(fs, fs->settle_time, settle_timeout);
            return;

        case do_transfer:
            if (fs->cur_cyl != fs->req_cyl) {
                if (fs->retries > 5) {
                    swim3_err("Wrong cylinder in transfer, want: %d got %d\n",
                          fs->req_cyl, fs->cur_cyl);
                    swim3_end_request(fs, -EIO, 0);
                    fs->state = idle;
                    return;
                }
                fs->state = seeking;
                break;
            }
            setup_transfer(fs);
            return;

        case jogging:
            seek_track(fs, -5);
            return;

        default:
            swim3_err("Unknown state %d\n", fs->state);
            return;
        }
    }
}

static void scan_timeout(unsigned long data)
{
    struct floppy_state *fs = (struct floppy_state *) data;
    struct swim3 __iomem *sw = fs->swim3;
    unsigned long flags;

    swim3_dbg("* scan timeout, state=%d\n", fs->state);

    spin_lock_irqsave(&swim3_lock, flags);
    fs->timeout_pending = 0;
    out_8(&sw->control_bic, DO_ACTION | WRITE_SECTORS);
    out_8(&sw->select, RELAX);
    out_8(&sw->intr_enable, 0);
    fs->cur_cyl = -1;
    if (fs->retries > 5) {
        swim3_end_request(fs, -EIO, 0);
        fs->state = idle;
        start_request(fs);
    } else {
        fs->state = jogging;
        act(fs);
    }
    spin_unlock_irqrestore(&swim3_lock, flags);
}

static void seek_timeout(unsigned long data)
{
    struct floppy_state *fs = (struct floppy_state *) data;
    struct swim3 __iomem *sw = fs->swim3;
    unsigned long flags;

    swim3_dbg("* seek timeout, state=%d\n", fs->state);

    spin_lock_irqsave(&swim3_lock, flags);
    fs->timeout_pending = 0;
    out_8(&sw->control_bic, DO_SEEK);
    out_8(&sw->select, RELAX);
    out_8(&sw->intr_enable, 0);
    swim3_err("%s", "Seek timeout\n");
    swim3_end_request(fs, -EIO, 0);
    fs->state = idle;
    start_request(fs);
    spin_unlock_irqrestore(&swim3_lock, flags);
}

static void settle_timeout(unsigned long data)
{
    struct floppy_state *fs = (struct floppy_state *) data;
    struct swim3 __iomem *sw = fs->swim3;
    unsigned long flags;

    swim3_dbg("* settle timeout, state=%d\n", fs->state);

    spin_lock_irqsave(&swim3_lock, flags);
    fs->timeout_pending = 0;
    if (swim3_readbit(fs, SEEK_COMPLETE)) {
        out_8(&sw->select, RELAX);
        fs->state = locating;
        act(fs);
        goto unlock;
    }
    out_8(&sw->select, RELAX);
    if (fs->settle_time < 2*HZ) {
        ++fs->settle_time;
        set_timeout(fs, 1, settle_timeout);
        goto unlock;
    }
    swim3_err("%s", "Seek settle timeout\n");
    swim3_end_request(fs, -EIO, 0);
    fs->state = idle;
    start_request(fs);
 unlock:
    spin_unlock_irqrestore(&swim3_lock, flags);
}

static void xfer_timeout(unsigned long data)
{
    struct floppy_state *fs = (struct floppy_state *) data;
    struct swim3 __iomem *sw = fs->swim3;
    struct dbdma_regs __iomem *dr = fs->dma;
    unsigned long flags;
    int n;

    swim3_dbg("* xfer timeout, state=%d\n", fs->state);

    spin_lock_irqsave(&swim3_lock, flags);
    fs->timeout_pending = 0;
    out_le32(&dr->control, RUN << 16);
    /* We must wait a bit for dbdma to stop */
    for (n = 0; (in_le32(&dr->status) & ACTIVE) && n < 1000; n++)
        udelay(1);
    out_8(&sw->intr_enable, 0);
    out_8(&sw->control_bic, WRITE_SECTORS | DO_ACTION);
    out_8(&sw->select, RELAX);
    swim3_err("Timeout %sing sector %ld\n",
           (rq_data_dir(fs->cur_req)==WRITE? "writ": "read"),
           (long)blk_rq_pos(fs->cur_req));
    swim3_end_request(fs, -EIO, 0);
    fs->state = idle;
    start_request(fs);
    spin_unlock_irqrestore(&swim3_lock, flags);
}

static irqreturn_t swim3_interrupt(int irq, void *dev_id)
{
    struct floppy_state *fs = (struct floppy_state *) dev_id;
    struct swim3 __iomem *sw = fs->swim3;
    int intr, err, n;
    int stat, resid;
    struct dbdma_regs __iomem *dr;
    struct dbdma_cmd *cp;
    unsigned long flags;
    struct request *req = fs->cur_req;

    swim3_dbg("* interrupt, state=%d\n", fs->state);

    spin_lock_irqsave(&swim3_lock, flags);
    intr = in_8(&sw->intr);
    err = (intr & ERROR_INTR)? in_8(&sw->error): 0;
    if ((intr & ERROR_INTR) && fs->state != do_transfer)
        swim3_err("Non-transfer error interrupt: state=%d, dir=%x, intr=%x, err=%x\n",
              fs->state, rq_data_dir(req), intr, err);
    switch (fs->state) {
    case locating:
        if (intr & SEEN_SECTOR) {
            out_8(&sw->control_bic, DO_ACTION | WRITE_SECTORS);
            out_8(&sw->select, RELAX);
            out_8(&sw->intr_enable, 0);
            del_timer(&fs->timeout);
            fs->timeout_pending = 0;
            if (sw->ctrack == 0xff) {
                swim3_err("%s", "Seen sector but cyl=ff?\n");
                fs->cur_cyl = -1;
                if (fs->retries > 5) {
                    swim3_end_request(fs, -EIO, 0);
                    fs->state = idle;
                    start_request(fs);
                } else {
                    fs->state = jogging;
                    act(fs);
                }
                break;
            }
            fs->cur_cyl = sw->ctrack;
            fs->cur_sector = sw->csect;
            if (fs->expect_cyl != -1 && fs->expect_cyl != fs->cur_cyl)
                swim3_err("Expected cyl %d, got %d\n",
                      fs->expect_cyl, fs->cur_cyl);
            fs->state = do_transfer;
            act(fs);
        }
        break;
    case seeking:
    case jogging:
        if (sw->nseek == 0) {
            out_8(&sw->control_bic, DO_SEEK);
            out_8(&sw->select, RELAX);
            out_8(&sw->intr_enable, 0);
            del_timer(&fs->timeout);
            fs->timeout_pending = 0;
            if (fs->state == seeking)
                ++fs->retries;
            fs->state = settling;
            act(fs);
        }
        break;
    case settling:
        out_8(&sw->intr_enable, 0);
        del_timer(&fs->timeout);
        fs->timeout_pending = 0;
        act(fs);
        break;
    case do_transfer:
        if ((intr & (ERROR_INTR | TRANSFER_DONE)) == 0)
            break;
        out_8(&sw->intr_enable, 0);
        out_8(&sw->control_bic, WRITE_SECTORS | DO_ACTION);
        out_8(&sw->select, RELAX);
        del_timer(&fs->timeout);
        fs->timeout_pending = 0;
        dr = fs->dma;
        cp = fs->dma_cmd;
        if (rq_data_dir(req) == WRITE)
            ++cp;
        /*
         * Check that the main data transfer has finished.
         * On writing, the swim3 sometimes doesn't use
         * up all the bytes of the postamble, so we can still
         * see DMA active here.  That doesn't matter as long
         * as all the sector data has been transferred.
         */
        if ((intr & ERROR_INTR) == 0 && cp->xfer_status == 0) {
            /* wait a little while for DMA to complete */
            for (n = 0; n < 100; ++n) {
                if (cp->xfer_status != 0)
                    break;
                udelay(1);
                barrier();
            }
        }
        /* turn off DMA */
        out_le32(&dr->control, (RUN | PAUSE) << 16);
        stat = ld_le16(&cp->xfer_status);
        resid = ld_le16(&cp->res_count);
        if (intr & ERROR_INTR) {
            n = fs->scount - 1 - resid / 512;
            if (n > 0) {
                blk_update_request(req, 0, n << 9);
                fs->req_sector += n;
            }
            if (fs->retries < 5) {
                ++fs->retries;
                act(fs);
            } else {
                swim3_err("Error %sing block %ld (err=%x)\n",
                       rq_data_dir(req) == WRITE? "writ": "read",
                       (long)blk_rq_pos(req), err);
                swim3_end_request(fs, -EIO, 0);
                fs->state = idle;
            }
        } else {
            if ((stat & ACTIVE) == 0 || resid != 0) {
                /* musta been an error */
                swim3_err("fd dma error: stat=%x resid=%d\n", stat, resid);
                swim3_err("  state=%d, dir=%x, intr=%x, err=%x\n",
                      fs->state, rq_data_dir(req), intr, err);
                swim3_end_request(fs, -EIO, 0);
                fs->state = idle;
                start_request(fs);
                break;
            }
            fs->retries = 0;
            if (swim3_end_request(fs, 0, fs->scount << 9)) {
                fs->req_sector += fs->scount;
                if (fs->req_sector > fs->secpertrack) {
                    fs->req_sector -= fs->secpertrack;
                    if (++fs->head > 1) {
                        fs->head = 0;
                        ++fs->req_cyl;
                    }
                }
                act(fs);
            } else
                fs->state = idle;
        }
        if (fs->state == idle)
            start_request(fs);
        break;
    default:
        swim3_err("Don't know what to do in state %d\n", fs->state);
    }
    spin_unlock_irqrestore(&swim3_lock, flags);
    return IRQ_HANDLED;
}

/*
static void fd_dma_interrupt(int irq, void *dev_id)
{
}
*/

/* Called under the mutex to grab exclusive access to a drive */
static int grab_drive(struct floppy_state *fs, enum swim_state state,
              int interruptible)
{
    unsigned long flags;

    swim3_dbg("%s", "-> grab drive\n");

    spin_lock_irqsave(&swim3_lock, flags);
    if (fs->state != idle && fs->state != available) {
        ++fs->wanted;
        while (fs->state != available) {
            spin_unlock_irqrestore(&swim3_lock, flags);
            if (interruptible && signal_pending(current)) {
                --fs->wanted;
                return -EINTR;
            }
            interruptible_sleep_on(&fs->wait);
            spin_lock_irqsave(&swim3_lock, flags);
        }
        --fs->wanted;
    }
    fs->state = state;
    spin_unlock_irqrestore(&swim3_lock, flags);

    return 0;
}

static void release_drive(struct floppy_state *fs)
{
    unsigned long flags;

    swim3_dbg("%s", "-> release drive\n");

    spin_lock_irqsave(&swim3_lock, flags);
    fs->state = idle;
    start_request(fs);
    spin_unlock_irqrestore(&swim3_lock, flags);
}

static int fd_eject(struct floppy_state *fs)
{
    int err, n;

    err = grab_drive(fs, ejecting, 1);
    if (err)
        return err;
    swim3_action(fs, EJECT);
    for (n = 20; n > 0; --n) {
        if (signal_pending(current)) {
            err = -EINTR;
            break;
        }
        swim3_select(fs, RELAX);
        schedule_timeout_interruptible(1);
        if (swim3_readbit(fs, DISK_IN) == 0)
            break;
    }
    swim3_select(fs, RELAX);
    udelay(150);
    fs->ejected = 1;
    release_drive(fs);
    return err;
}

static struct floppy_struct floppy_type =
    { 2880,18,2,80,0,0x1B,0x00,0xCF,0x6C,NULL };    /*  7 1.44MB 3.5"   */

static int floppy_locked_ioctl(struct block_device *bdev, fmode_t mode,
            unsigned int cmd, unsigned long param)
{
    struct floppy_state *fs = bdev->bd_disk->private_data;
    int err;
        
    if ((cmd & 0x80) && !capable(CAP_SYS_ADMIN))
        return -EPERM;

    if (fs->mdev->media_bay &&
        check_media_bay(fs->mdev->media_bay) != MB_FD)
        return -ENXIO;

    switch (cmd) {
    case FDEJECT:
        if (fs->ref_count != 1)
            return -EBUSY;
        err = fd_eject(fs);
        return err;
    case FDGETPRM:
            if (copy_to_user((void __user *) param, &floppy_type,
                 sizeof(struct floppy_struct)))
            return -EFAULT;
        return 0;
    }
    return -ENOTTY;
}

static int floppy_ioctl(struct block_device *bdev, fmode_t mode,
                 unsigned int cmd, unsigned long param)
{
    int ret;

    mutex_lock(&swim3_mutex);
    ret = floppy_locked_ioctl(bdev, mode, cmd, param);
    mutex_unlock(&swim3_mutex);

    return ret;
}

static int floppy_open(struct block_device *bdev, fmode_t mode)
{
    struct floppy_state *fs = bdev->bd_disk->private_data;
    struct swim3 __iomem *sw = fs->swim3;
    int n, err = 0;

    if (fs->ref_count == 0) {
        if (fs->mdev->media_bay &&
            check_media_bay(fs->mdev->media_bay) != MB_FD)
            return -ENXIO;
        out_8(&sw->setup, S_IBM_DRIVE | S_FCLK_DIV2);
        out_8(&sw->control_bic, 0xff);
        out_8(&sw->mode, 0x95);
        udelay(10);
        out_8(&sw->intr_enable, 0);
        out_8(&sw->control_bis, DRIVE_ENABLE | INTR_ENABLE);
        swim3_action(fs, MOTOR_ON);
        fs->write_prot = -1;
        fs->cur_cyl = -1;
        for (n = 0; n < 2 * HZ; ++n) {
            if (n >= HZ/30 && swim3_readbit(fs, SEEK_COMPLETE))
                break;
            if (signal_pending(current)) {
                err = -EINTR;
                break;
            }
            swim3_select(fs, RELAX);
            schedule_timeout_interruptible(1);
        }
        if (err == 0 && (swim3_readbit(fs, SEEK_COMPLETE) == 0
                 || swim3_readbit(fs, DISK_IN) == 0))
            err = -ENXIO;
        swim3_action(fs, SETMFM);
        swim3_select(fs, RELAX);

    } else if (fs->ref_count == -1 || mode & FMODE_EXCL)
        return -EBUSY;

    if (err == 0 && (mode & FMODE_NDELAY) == 0
        && (mode & (FMODE_READ|FMODE_WRITE))) {
        check_disk_change(bdev);
        if (fs->ejected)
            err = -ENXIO;
    }

    if (err == 0 && (mode & FMODE_WRITE)) {
        if (fs->write_prot < 0)
            fs->write_prot = swim3_readbit(fs, WRITE_PROT);
        if (fs->write_prot)
            err = -EROFS;
    }

    if (err) {
        if (fs->ref_count == 0) {
            swim3_action(fs, MOTOR_OFF);
            out_8(&sw->control_bic, DRIVE_ENABLE | INTR_ENABLE);
            swim3_select(fs, RELAX);
        }
        return err;
    }

    if (mode & FMODE_EXCL)
        fs->ref_count = -1;
    else
        ++fs->ref_count;

    return 0;
}

static int floppy_unlocked_open(struct block_device *bdev, fmode_t mode)
{
    int ret;

    mutex_lock(&swim3_mutex);
    ret = floppy_open(bdev, mode);
    mutex_unlock(&swim3_mutex);

    return ret;
}

static int floppy_release(struct gendisk *disk, fmode_t mode)
{
    struct floppy_state *fs = disk->private_data;
    struct swim3 __iomem *sw = fs->swim3;

    mutex_lock(&swim3_mutex);
    if (fs->ref_count > 0 && --fs->ref_count == 0) {
        swim3_action(fs, MOTOR_OFF);
        out_8(&sw->control_bic, 0xff);
        swim3_select(fs, RELAX);
    }
    mutex_unlock(&swim3_mutex);
    return 0;
}

static unsigned int floppy_check_events(struct gendisk *disk,
                    unsigned int clearing)
{
    struct floppy_state *fs = disk->private_data;
    return fs->ejected ? DISK_EVENT_MEDIA_CHANGE : 0;
}

static int floppy_revalidate(struct gendisk *disk)
{
    struct floppy_state *fs = disk->private_data;
    struct swim3 __iomem *sw;
    int ret, n;

    if (fs->mdev->media_bay &&
        check_media_bay(fs->mdev->media_bay) != MB_FD)
        return -ENXIO;

    sw = fs->swim3;
    grab_drive(fs, revalidating, 0);
    out_8(&sw->intr_enable, 0);
    out_8(&sw->control_bis, DRIVE_ENABLE);
    swim3_action(fs, MOTOR_ON); /* necessary? */
    fs->write_prot = -1;
    fs->cur_cyl = -1;
    mdelay(1);
    for (n = HZ; n > 0; --n) {
        if (swim3_readbit(fs, SEEK_COMPLETE))
            break;
        if (signal_pending(current))
            break;
        swim3_select(fs, RELAX);
        schedule_timeout_interruptible(1);
    }
    ret = swim3_readbit(fs, SEEK_COMPLETE) == 0
        || swim3_readbit(fs, DISK_IN) == 0;
    if (ret)
        swim3_action(fs, MOTOR_OFF);
    else {
        fs->ejected = 0;
        swim3_action(fs, SETMFM);
    }
    swim3_select(fs, RELAX);

    release_drive(fs);
    return ret;
}

static const struct block_device_operations floppy_fops = {
    .open       = floppy_unlocked_open,
    .release    = floppy_release,
    .ioctl      = floppy_ioctl,
    .check_events   = floppy_check_events,
    .revalidate_disk= floppy_revalidate,
};

static void swim3_mb_event(struct macio_dev* mdev, int mb_state)
{
    struct floppy_state *fs = macio_get_drvdata(mdev);
    struct swim3 __iomem *sw = fs->swim3;

    if (!fs)
        return;
    if (mb_state != MB_FD)
        return;

    /* Clear state */
    out_8(&sw->intr_enable, 0);
    in_8(&sw->intr);
    in_8(&sw->error);
}

static int swim3_add_device(struct macio_dev *mdev, int index)
{
    struct device_node *swim = mdev->ofdev.dev.of_node;
    struct floppy_state *fs = &floppy_states[index];
    int rc = -EBUSY;

    /* Do this first for message macros */
    memset(fs, 0, sizeof(*fs));
    fs->mdev = mdev;
    fs->index = index;

    /* Check & Request resources */
    if (macio_resource_count(mdev) < 2) {
        swim3_err("%s", "No address in device-tree\n");
        return -ENXIO;
    }
    if (macio_irq_count(mdev) < 1) {
        swim3_err("%s", "No interrupt in device-tree\n");
        return -ENXIO;
    }
    if (macio_request_resource(mdev, 0, "swim3 (mmio)")) {
        swim3_err("%s", "Can't request mmio resource\n");
        return -EBUSY;
    }
    if (macio_request_resource(mdev, 1, "swim3 (dma)")) {
        swim3_err("%s", "Can't request dma resource\n");
        macio_release_resource(mdev, 0);
        return -EBUSY;
    }
    dev_set_drvdata(&mdev->ofdev.dev, fs);

    if (mdev->media_bay == NULL)
        pmac_call_feature(PMAC_FTR_SWIM3_ENABLE, swim, 0, 1);
    
    fs->state = idle;
    fs->swim3 = (struct swim3 __iomem *)
        ioremap(macio_resource_start(mdev, 0), 0x200);
    if (fs->swim3 == NULL) {
        swim3_err("%s", "Couldn't map mmio registers\n");
        rc = -ENOMEM;
        goto out_release;
    }
    fs->dma = (struct dbdma_regs __iomem *)
        ioremap(macio_resource_start(mdev, 1), 0x200);
    if (fs->dma == NULL) {
        swim3_err("%s", "Couldn't map dma registers\n");
        iounmap(fs->swim3);
        rc = -ENOMEM;
        goto out_release;
    }
    fs->swim3_intr = macio_irq(mdev, 0);
    fs->dma_intr = macio_irq(mdev, 1);
    fs->cur_cyl = -1;
    fs->cur_sector = -1;
    fs->secpercyl = 36;
    fs->secpertrack = 18;
    fs->total_secs = 2880;
    init_waitqueue_head(&fs->wait);

    fs->dma_cmd = (struct dbdma_cmd *) DBDMA_ALIGN(fs->dbdma_cmd_space);
    memset(fs->dma_cmd, 0, 2 * sizeof(struct dbdma_cmd));
    st_le16(&fs->dma_cmd[1].command, DBDMA_STOP);

    if (mdev->media_bay == NULL || check_media_bay(mdev->media_bay) == MB_FD)
        swim3_mb_event(mdev, MB_FD);

    if (request_irq(fs->swim3_intr, swim3_interrupt, 0, "SWIM3", fs)) {
        swim3_err("%s", "Couldn't request interrupt\n");
        pmac_call_feature(PMAC_FTR_SWIM3_ENABLE, swim, 0, 0);
        goto out_unmap;
        return -EBUSY;
    }

    init_timer(&fs->timeout);

    swim3_info("SWIM3 floppy controller %s\n",
        mdev->media_bay ? "in media bay" : "");

    return 0;

 out_unmap:
    iounmap(fs->dma);
    iounmap(fs->swim3);

 out_release:
    macio_release_resource(mdev, 0);
    macio_release_resource(mdev, 1);

    return rc;
}

static int __devinit swim3_attach(struct macio_dev *mdev, const struct of_device_id *match)
{
    struct gendisk *disk;
    int index, rc;

    index = floppy_count++;
    if (index >= MAX_FLOPPIES)
        return -ENXIO;

    /* Add the drive */
    rc = swim3_add_device(mdev, index);
    if (rc)
        return rc;
    /* Now register that disk. Same comment about failure handling */
    disk = disks[index] = alloc_disk(1);
    if (disk == NULL)
        return -ENOMEM;
    disk->queue = blk_init_queue(do_fd_request, &swim3_lock);
    if (disk->queue == NULL) {
        put_disk(disk);
        return -ENOMEM;
    }
    disk->queue->queuedata = &floppy_states[index];

    if (index == 0) {
        /* If we failed, there isn't much we can do as the driver is still
         * too dumb to remove the device, just bail out
         */
        if (register_blkdev(FLOPPY_MAJOR, "fd"))
            return 0;
    }

    disk->major = FLOPPY_MAJOR;
    disk->first_minor = index;
    disk->fops = &floppy_fops;
    disk->private_data = &floppy_states[index];
    disk->flags |= GENHD_FL_REMOVABLE;
    sprintf(disk->disk_name, "fd%d", index);
    set_capacity(disk, 2880);
    add_disk(disk);

    return 0;
}

static struct of_device_id swim3_match[] =
{
    {
    .name       = "swim3",
    },
    {
    .compatible = "ohare-swim3"
    },
    {
    .compatible = "swim3"
    },
    { /* end of list */ }
};

static struct macio_driver swim3_driver =
{
    .driver = {
        .name       = "swim3",
        .of_match_table = swim3_match,
    },
    .probe      = swim3_attach,
#ifdef CONFIG_PMAC_MEDIABAY
    .mediabay_event = swim3_mb_event,
#endif
#if 0
    .suspend    = swim3_suspend,
    .resume     = swim3_resume,
#endif
};


int swim3_init(void)
{
    macio_register_driver(&swim3_driver);
    return 0;
}

module_init(swim3_init)

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Paul Mackerras");
MODULE_ALIAS_BLOCKDEV_MAJOR(FLOPPY_MAJOR);