/*
 * 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/signal.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 <linux/wait.h>
#include <asm/io.h>
#include <asm/dbdma.h>
#include <asm/prom.h>
#include <linux/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 ONEMEG_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 GCR_MODE        13
#define SEEK_COMPLETE   14
#define TWOMEG_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(struct timer_list *t);
static void seek_timeout(struct timer_list *t);
static void settle_timeout(struct timer_list *t);
static void xfer_timeout(struct timer_list *t);
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 void 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, blk_status_t 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, BLK_STS_IOERR, 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),
                          bio_data(req->bio));
                swim3_dbg("           current_nr_sectors=%u\n",
                          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, BLK_STS_IOERR, 0);
                        continue;
                }
                if (fs->ejected) {
                        swim3_dbg("%s", "  disk ejected\n");
                        swim3_end_request(fs, BLK_STS_IOERR, 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, BLK_STS_IOERR, 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)(struct timer_list *t))
{
        if (fs->timeout_pending)
                del_timer(&fs->timeout);
        fs->timeout.expires = jiffies + nticks;
        fs->timeout.function = proc;
        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)
{
        cp->req_count = cpu_to_le16(count);
        cp->command = cpu_to_le16(cmd);
        cp->phy_addr = cpu_to_le32(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, bio_data(req->bio), 512);
                ++cp;
                init_dma(cp, OUTPUT_LAST, write_postamble, sizeof(write_postamble));
        } else {
                init_dma(cp, INPUT_LAST, bio_data(req->bio), 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, BLK_STS_IOERR, 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(struct timer_list *t)
{
        struct floppy_state *fs = from_timer(fs, t, timeout);
        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, BLK_STS_IOERR, 0);
                fs->state = idle;
                start_request(fs);
        } else {
                fs->state = jogging;
                act(fs);
        }
        spin_unlock_irqrestore(&swim3_lock, flags);
}

static void seek_timeout(struct timer_list *t)
{
        struct floppy_state *fs = from_timer(fs, t, timeout);
        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, BLK_STS_IOERR, 0);
        fs->state = idle;
        start_request(fs);
        spin_unlock_irqrestore(&swim3_lock, flags);
}

static void settle_timeout(struct timer_list *t)
{
        struct floppy_state *fs = from_timer(fs, t, timeout);
        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, BLK_STS_IOERR, 0);
        fs->state = idle;
        start_request(fs);
 unlock:
        spin_unlock_irqrestore(&swim3_lock, flags);
}

static void xfer_timeout(struct timer_list *t)
{
        struct floppy_state *fs = from_timer(fs, t, timeout);
        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, BLK_STS_IOERR, 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, BLK_STS_IOERR, 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 = le16_to_cpu(cp->xfer_status);
                resid = le16_to_cpu(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, BLK_STS_IOERR, 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, BLK_STS_IOERR, 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;
                /* this will enable irqs in order to sleep */
                if (!interruptible)
                        wait_event_lock_irq(fs->wait,
                                        fs->state == available,
                                        swim3_lock);
                else if (wait_event_interruptible_lock_irq(fs->wait,
                                        fs->state == available,
                                        swim3_lock)) {
                        --fs->wanted;
                        spin_unlock_irqrestore(&swim3_lock, flags);
                        return -EINTR;
                }
                --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 void 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);
}

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;

        if (!fs)
                return;

        sw = fs->swim3;

        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));
        fs->dma_cmd[1].command = cpu_to_le16(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;
        }

        timer_setup(&fs->timeout, NULL, 0);

        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 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;
        }
        blk_queue_bounce_limit(disk->queue, BLK_BOUNCE_HIGH);
        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 const 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);