FreeBSD/Linux Kernel Cross Reference
sys/i386/isa/wt.c

     
     /*
      * Streamer tape driver for 386bsd and FreeBSD.
      * Supports Archive and Wangtek compatible QIC-02/QIC-36 boards.
      *
      * Copyright (C) 1993 by:
      *      Sergey Ryzhkov       <sir@kiae.su>
      *      Serge Vakulenko      <vak@zebub.msk.su>
      *
     * This software is distributed with NO WARRANTIES, not even the implied
     * warranties for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
     *
     * Authors grant any other persons or organisations permission to use
     * or modify this software as long as this message is kept with the software,
     * all derivative works or modified versions.
     *
     * This driver is derived from the old 386bsd Wangtek streamer tape driver,
     * made by Robert Baron at CMU, based on Intel sources.
     * Authors thank Robert Baron, CMU and Intel and retain here
     * the original CMU copyright notice.
     *
     * Version 1.3, Thu Nov 11 12:09:13 MSK 1993
     * $FreeBSD: src/sys/i386/isa/wt.c,v 1.35.2.2 1999/09/05 08:13:45 peter Exp $
     *
     */
    
    /*
     * Code for MTERASE added by John Lind (john@starfire.mn.org) 95/09/02.
     * This was very easy due to the excellent structure and clear coding
     * of the original driver.
     */
    
    /*
     * Copyright (c) 1989 Carnegie-Mellon University.
     * All rights reserved.
     *
     * Authors: Robert Baron
     *
     * Permission to use, copy, modify and distribute this software and
     * its documentation is hereby granted, provided that both the copyright
     * notice and this permission notice appear in all copies of the
     * software, derivative works or modified versions, and any portions
     * thereof, and that both notices appear in supporting documentation.
     *
     * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
     * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     *
     * Carnegie Mellon requests users of this software to return to
     *
     *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
     *  School of Computer Science
     *  Carnegie Mellon University
     *  Pittsburgh PA 15213-3890
     *
     * any improvements or extensions that they make and grant Carnegie the
     * rights to redistribute these changes.
     */
    
    #include "wt.h"
    #if NWT > 0
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/buf.h>
    #include <sys/fcntl.h>
    #include <sys/malloc.h>
    #include <sys/ioctl.h>
    #include <sys/mtio.h>
    #include <sys/proc.h>
    #include <sys/conf.h>
    #ifdef DEVFS
    #include <sys/devfsext.h>
    #endif /*DEVFS*/
    #include <vm/vm_param.h>
    
    #include <machine/clock.h>
    #include <machine/wtio.h>
    
    #include <i386/isa/isa_device.h>
    #include <i386/isa/wtreg.h>
    
    
    /*
     * Uncomment this to enable internal device tracing.
     */
    #define TRACE(s)                /* printf s */
    
    #define WTPRI                   (PZERO+10)      /* sleep priority */
    
    /*
     * Wangtek controller ports
     */
    #define WT_CTLPORT(base)        ((base)+0)      /* control, write only */
    #define WT_STATPORT(base)       ((base)+0)      /* status, read only */
    #define WT_CMDPORT(base)        ((base)+1)      /* command, write only */
    #define WT_DATAPORT(base)       ((base)+1)      /* data, read only */
    #define WT_NPORT                2               /* 2 i/o ports */
   
   /* status port bits */
   #define WT_BUSY                 0x01            /* not ready bit define */
   #define WT_NOEXCEP              0x02            /* no exception bit define */
   #define WT_RESETMASK            0x07            /* to check after reset */
   #define WT_RESETVAL             0x05            /* state after reset */
   
   /* control port bits */
   #define WT_ONLINE               0x01            /* device selected */
   #define WT_RESET                0x02            /* reset command */
   #define WT_REQUEST              0x04            /* request command */
   #define WT_IEN                  0x08            /* enable dma */
   
   /*
    * Archive controller ports
    */
   #define AV_DATAPORT(base)       ((base)+0)      /* data, read only */
   #define AV_CMDPORT(base)        ((base)+0)      /* command, write only */
   #define AV_STATPORT(base)       ((base)+1)      /* status, read only */
   #define AV_CTLPORT(base)        ((base)+1)      /* control, write only */
   #define AV_SDMAPORT(base)       ((base)+2)      /* start dma */
   #define AV_RDMAPORT(base)       ((base)+3)      /* reset dma */
   #define AV_NPORT                4               /* 4 i/o ports */
   
   /* status port bits */
   #define AV_BUSY                 0x40            /* not ready bit define */
   #define AV_NOEXCEP              0x20            /* no exception bit define */
   #define AV_RESETMASK            0xf8            /* to check after reset */
   #define AV_RESETVAL             0x50            /* state after reset */
   
   /* control port bits */
   #define AV_RESET                0x80            /* reset command */
   #define AV_REQUEST              0x40            /* request command */
   #define AV_IEN                  0x20            /* enable interrupts */
   
   enum wttype {
           UNKNOWN = 0,                    /* unknown type, driver disabled */
           ARCHIVE,                        /* Archive Viper SC499, SC402 etc */
           WANGTEK,                        /* Wangtek */
   };
   
   typedef struct {
           unsigned short err;             /* code for error encountered */
           unsigned short ercnt;           /* number of error blocks */
           unsigned short urcnt;           /* number of underruns */
   } wtstatus_t;
   
   typedef struct {
           enum wttype type;               /* type of controller */
           unsigned unit;                  /* unit number */
           unsigned port;                  /* base i/o port */
           unsigned chan;                  /* dma channel number, 1..3 */
           unsigned flags;                 /* state of tape drive */
           unsigned dens;                  /* tape density */
           int bsize;                      /* tape block size */
           void *buf;                      /* internal i/o buffer */
   
           void *dmavaddr;                 /* virtual address of dma i/o buffer */
           unsigned dmatotal;              /* size of i/o buffer */
           unsigned dmaflags;              /* i/o direction, B_READ or B_WRITE */
           unsigned dmacount;              /* resulting length of dma i/o */
   
           wtstatus_t error;               /* status of controller */
   
           unsigned short DATAPORT, CMDPORT, STATPORT, CTLPORT, SDMAPORT, RDMAPORT;
           unsigned char BUSY, NOEXCEP, RESETMASK, RESETVAL;
           unsigned char ONLINE, RESET, REQUEST, IEN;
   #ifdef  DEVFS
           void    *devfs_token;
           void    *devfs_token_r;
   #endif
   } wtinfo_t;
   
   static wtinfo_t wttab[NWT];                    /* tape info by unit number */
   
   static int wtwait (wtinfo_t *t, int catch, char *msg);
   static int wtcmd (wtinfo_t *t, int cmd);
   static int wtstart (wtinfo_t *t, unsigned mode, void *vaddr, unsigned len);
   static void wtdma (wtinfo_t *t);
   static timeout_t wtimer;
   static void wtclock (wtinfo_t *t);
   static int wtreset (wtinfo_t *t);
   static int wtsense (wtinfo_t *t, int verb, int ignor);
   static int wtstatus (wtinfo_t *t);
   static void wtrewind (wtinfo_t *t);
   static int wtreadfm (wtinfo_t *t);
   static int wtwritefm (wtinfo_t *t);
   static int wtpoll (wtinfo_t *t, int mask, int bits);
   
   static  d_open_t        wtopen;
   static  d_close_t       wtclose;
   static  d_ioctl_t       wtioctl;
   static  d_dump_t        wtdump;
   static  d_psize_t       wtsize;
   static  d_strategy_t    wtstrategy;
   
   #define CDEV_MAJOR 10
   #define BDEV_MAJOR 3
   
   static struct cdevsw wt_cdevsw;
   static struct bdevsw wt_bdevsw = 
           { wtopen,       wtclose,        wtstrategy,     wtioctl,        /*3*/
             wtdump,       wtsize,         B_TAPE, "wt",   &wt_cdevsw,     -1 };
   
   
   /*
    * Probe for the presence of the device.
    */
   static int 
   wtprobe (struct isa_device *id)
   {
           wtinfo_t *t = wttab + id->id_unit;
   
           t->unit = id->id_unit;
           t->chan = id->id_drq;
           t->port = id->id_iobase;
           if (t->chan<1 || t->chan>3) {
                   printf ("wt%d: Bad drq=%d, should be 1..3\n", t->unit, t->chan);
                   return (0);
           }
   
           /* Try Wangtek. */
           t->type = WANGTEK;
           t->CTLPORT = WT_CTLPORT (t->port);  t->STATPORT = WT_STATPORT (t->port);
           t->CMDPORT = WT_CMDPORT (t->port);  t->DATAPORT = WT_DATAPORT (t->port);
           t->SDMAPORT = 0;                    t->RDMAPORT = 0;
           t->BUSY = WT_BUSY;                  t->NOEXCEP = WT_NOEXCEP;
           t->RESETMASK = WT_RESETMASK;        t->RESETVAL = WT_RESETVAL;
           t->ONLINE = WT_ONLINE;              t->RESET = WT_RESET;
           t->REQUEST = WT_REQUEST;            t->IEN = WT_IEN;
           if (wtreset (t))
                   return (WT_NPORT);
   
           /* Try Archive. */
           t->type = ARCHIVE;
           t->CTLPORT = AV_CTLPORT (t->port);  t->STATPORT = AV_STATPORT (t->port);
           t->CMDPORT = AV_CMDPORT (t->port);  t->DATAPORT = AV_DATAPORT (t->port);
           t->SDMAPORT = AV_SDMAPORT (t->port); t->RDMAPORT = AV_RDMAPORT (t->port);
           t->BUSY = AV_BUSY;                  t->NOEXCEP = AV_NOEXCEP;
           t->RESETMASK = AV_RESETMASK;        t->RESETVAL = AV_RESETVAL;
           t->ONLINE = 0;                      t->RESET = AV_RESET;
           t->REQUEST = AV_REQUEST;            t->IEN = AV_IEN;
           if (wtreset (t))
                   return (AV_NPORT);
   
           /* Tape controller not found. */
           t->type = UNKNOWN;
           return (0);
   }
   
   /*
    * Device is found, configure it.
    */
   static int
   wtattach (struct isa_device *id)
   {
           wtinfo_t *t = wttab + id->id_unit;
   
           if (t->type == ARCHIVE) {
                   printf ("wt%d: type <Archive>\n", t->unit);
                   outb (t->RDMAPORT, 0);          /* reset dma */
           } else
                   printf ("wt%d: type <Wangtek>\n", t->unit);
           t->flags = TPSTART;                     /* tape is rewound */
           t->dens = -1;                           /* unknown density */
           isa_dmainit(t->chan, 1024);
   
   #ifdef DEVFS
           t->devfs_token_r = 
                   devfs_add_devswf(&wt_cdevsw, id->id_unit, DV_CHR, 0, 0, 
                                    0600, "rwt%d", id->id_unit);
           t->devfs_token = 
                   devfs_add_devswf(&wt_bdevsw, id->id_unit, DV_BLK, 0, 0, 
                                    0600, "wt%d", id->id_unit);
   #endif
           return (1);
   }
   
   struct isa_driver wtdriver = { wtprobe, wtattach, "wt", };
   
   int
   wtdump (dev_t dev)
   {
           /* Not implemented */
           return (EINVAL);
   }
   
   int
   wtsize (dev_t dev)
   {
           /* Not implemented */
           return (-1);
   }
   
   /*
    * Open routine, called on every device open.
    */
   int
   wtopen (dev_t dev, int flag, int fmt, struct proc *p)
   {
           int u = minor (dev) & T_UNIT;
           wtinfo_t *t = wttab + u;
           int error;
   
           if (u >= NWT || t->type == UNKNOWN)
                   return (ENXIO);
   
           /* Check that device is not in use */
           if (t->flags & TPINUSE)
                   return (EBUSY);
   
           /* If the tape is in rewound state, check the status and set density. */
           if (t->flags & TPSTART) {
                   /* If rewind is going on, wait */
                   if (error = wtwait (t, PCATCH, "wtrew"))
                           return (error);
   
                   /* Check the controller status */
                   if (! wtsense (t, 0, (flag & FWRITE) ? 0 : TP_WRP)) {
                           /* Bad status, reset the controller */
                           if (! wtreset (t))
                                   return (EIO);
                           if (! wtsense (t, 1, (flag & FWRITE) ? 0 : TP_WRP))
                                   return (EIO);
                   }
   
                   /* Set up tape density. */
                   if (t->dens != (minor (dev) & WT_DENSEL)) {
                           int d = 0;
   
                           switch (minor (dev) & WT_DENSEL) {
                           case WT_DENSDFLT: default: break; /* default density */
                           case WT_QIC11:  d = QIC_FMT11;  break; /* minor 010 */
                           case WT_QIC24:  d = QIC_FMT24;  break; /* minor 020 */
                           case WT_QIC120: d = QIC_FMT120; break; /* minor 030 */
                           case WT_QIC150: d = QIC_FMT150; break; /* minor 040 */
                           case WT_QIC300: d = QIC_FMT300; break; /* minor 050 */
                           case WT_QIC600: d = QIC_FMT600; break; /* minor 060 */
                           }
                           if (d) {
                                   /* Change tape density. */
                                   if (! wtcmd (t, d))
                                           return (EIO);
                                   if (! wtsense (t, 1, TP_WRP | TP_ILL))
                                           return (EIO);
   
                                   /* Check the status of the controller. */
                                   if (t->error.err & TP_ILL) {
                                           printf ("wt%d: invalid tape density\n", t->unit);
                                           return (ENODEV);
                                   }
                           }
                           t->dens = minor (dev) & WT_DENSEL;
                   }
                   t->flags &= ~TPSTART;
           } else if (t->dens != (minor (dev) & WT_DENSEL))
                   return (ENXIO);
   
           t->bsize = (minor (dev) & WT_BSIZE) ? 1024 : 512;
           t->buf = malloc (t->bsize, M_TEMP, M_WAITOK);
           if (! t->buf)
                   return (EAGAIN);
   
           if (isa_dma_acquire(t->chan))
                   return(EBUSY);
   
           t->flags = TPINUSE;
   
           if (flag & FREAD)
                   t->flags |= TPREAD;
           if (flag & FWRITE)
                   t->flags |= TPWRITE;
           return (0);
   }
   
   /*
    * Close routine, called on last device close.
    */
   int
   wtclose (dev_t dev, int flags, int fmt, struct proc *p)
   {
           int u = minor (dev) & T_UNIT;
           wtinfo_t *t = wttab + u;
   
           if (u >= NWT || t->type == UNKNOWN)
                   return (ENXIO);
   
           /* If rewind is pending, do nothing */
           if (t->flags & TPREW)
                   goto done;
   
           /* If seek forward is pending and no rewind on close, do nothing */
           if (t->flags & TPRMARK) {
                   if (minor (dev) & T_NOREWIND)
                           goto done;
   
                   /* If read file mark is going on, wait */
                   wtwait (t, 0, "wtrfm");
           }
   
           if (t->flags & TPWANY)
                   /* Tape was written.  Write file mark. */
                   wtwritefm (t);
   
           if (! (minor (dev) & T_NOREWIND)) {
                   /* Rewind tape to beginning of tape. */
                   /* Don't wait until rewind, though. */
                   wtrewind (t);
                   goto done;
           }
           if ((t->flags & TPRANY) && ! (t->flags & (TPVOL | TPWANY)))
                   /* Space forward to after next file mark if no writing done. */
                   /* Don't wait for completion. */
                   wtreadfm (t);
   done:
           t->flags &= TPREW | TPRMARK | TPSTART | TPTIMER;
           free (t->buf, M_TEMP);
           isa_dma_release(t->chan);
           return (0);
   }
   
   /*
    * Ioctl routine.  Compatible with BSD ioctls.
    * There are two possible ioctls:
    * ioctl (int fd, MTIOCGET, struct mtget *buf)  -- get status
    * ioctl (int fd, MTIOCTOP, struct mtop *buf)   -- do BSD-like op
    */
   int
   wtioctl (dev_t dev, int cmd, caddr_t arg, int flags, struct proc *p)
   {
           int u = minor (dev) & T_UNIT;
           wtinfo_t *t = wttab + u;
           int error, count, op;
   
           if (u >= NWT || t->type == UNKNOWN)
                   return (ENXIO);
   
           switch (cmd) {
           default:
                   return (EINVAL);
           case MTIOCIEOT:         /* ignore EOT errors */
           case MTIOCEEOT:         /* enable EOT errors */
                   return (0);
           case MTIOCGET:
                   ((struct mtget*)arg)->mt_type =
                           t->type == ARCHIVE ? MT_ISVIPER1 : 0x11;
                   ((struct mtget*)arg)->mt_dsreg = t->flags;      /* status */
                   ((struct mtget*)arg)->mt_erreg = t->error.err;  /* errors */
                   ((struct mtget*)arg)->mt_resid = 0;
                   ((struct mtget*)arg)->mt_fileno = 0;            /* file */
                   ((struct mtget*)arg)->mt_blkno = 0;             /* block */
                   return (0);
           case MTIOCTOP:
                   break;
           }
           switch ((short) ((struct mtop*)arg)->mt_op) {
           default:
           case MTFSR:             /* forward space record */
           case MTBSR:             /* backward space record */
           case MTBSF:             /* backward space file */
                   break;
           case MTNOP:             /* no operation, sets status only */
           case MTCACHE:           /* enable controller cache */
           case MTNOCACHE:         /* disable controller cache */
                   return (0);
           case MTREW:             /* rewind */
           case MTOFFL:            /* rewind and put the drive offline */
                   if (t->flags & TPREW)   /* rewind is running */
                           return (0);
                   if (error = wtwait (t, PCATCH, "wtorew"))
                           return (error);
                   wtrewind (t);
                   return (0);
           case MTFSF:             /* forward space file */
                   for (count=((struct mtop*)arg)->mt_count; count>0; --count) {
                           if (error = wtwait (t, PCATCH, "wtorfm"))
                                   return (error);
                           if (error = wtreadfm (t))
                                   return (error);
                   }
                   return (0);
           case MTWEOF:            /* write an end-of-file record */
                   if (! (t->flags & TPWRITE) || (t->flags & TPWP))
                           return (EACCES);
                   if (error = wtwait (t, PCATCH, "wtowfm"))
                           return (error);
                   if (error = wtwritefm (t))
                           return (error);
                   return (0);
           case MTRETENS:          /* re-tension tape */
                   if (error = wtwait (t, PCATCH, "wtretens"))
                           return (error);
                   op = QIC_RETENS;
                   goto erase_retens;
                   
           case MTERASE:           /* erase to EOM */
                   if (! (t->flags & TPWRITE) || (t->flags & TPWP))
                           return (EACCES);
                   if (error = wtwait (t, PCATCH, "wterase"))
                           return (error);
                   op = QIC_ERASE;
           erase_retens:
                   /* ERASE and RETENS operations work like REWIND. */
                   /* Simulate the rewind operation here. */
                   t->flags &= ~(TPRO | TPWO | TPVOL);
                   if (! wtcmd (t, op))
                           return (EIO);
                   t->flags |= TPSTART | TPREW;
                   t->flags |= TPWANY;
                   wtclock (t);
                   return (0);
           }
           return (EINVAL);
   }
   
   /*
    * Strategy routine.
    */
   void
   wtstrategy (struct buf *bp)
   {
           int u = minor (bp->b_dev) & T_UNIT;
           wtinfo_t *t = wttab + u;
           int s;
   
           bp->b_resid = bp->b_bcount;
           if (u >= NWT || t->type == UNKNOWN) {
                   bp->b_error = ENXIO;
                   goto err2xit;
           }
   
           /* at file marks and end of tape, we just return '0 bytes available' */
           if (t->flags & TPVOL)
                   goto xit;
   
           if (bp->b_bcount % t->bsize != 0) {
                   bp->b_error = EINVAL;
                   goto err2xit;
           }
   
           if (bp->b_flags & B_READ) {
                   /* Check read access and no previous write to this tape. */
                   if (! (t->flags & TPREAD) || (t->flags & TPWANY))
                           goto errxit;
   
                   /* For now, we assume that all data will be copied out */
                   /* If read command outstanding, just skip down */
                   if (! (t->flags & TPRO)) {
                           if (! wtsense (t, 1, TP_WRP))   /* clear status */
                                   goto errxit;
                           if (! wtcmd (t, QIC_RDDATA)) {  /* sed read mode */
                                   wtsense (t, 1, TP_WRP);
                                   goto errxit;
                           }
                           t->flags |= TPRO | TPRANY;
                   }
           } else {
                   /* Check write access and write protection. */
                   /* No previous read from this tape allowed. */
                   if (! (t->flags & TPWRITE) || (t->flags & (TPWP | TPRANY)))
                           goto errxit;
   
                   /* If write command outstanding, just skip down */
                   if (! (t->flags & TPWO)) {
                           if (! wtsense (t, 1, 0))        /* clear status */
                                   goto errxit;
                           if (! wtcmd (t, QIC_WRTDATA)) { /* set write mode */
                                   wtsense (t, 1, 0);
                                   goto errxit;
                           }
                           t->flags |= TPWO | TPWANY;
                   }
           }
   
           if (! bp->b_bcount)
                   goto xit;
   
           t->flags &= ~TPEXCEP;
           s = splbio ();
           if (wtstart (t, bp->b_flags, bp->b_un.b_addr, bp->b_bcount)) {
                   wtwait (t, 0, (bp->b_flags & B_READ) ? "wtread" : "wtwrite");
                   bp->b_resid -= t->dmacount;
           }
           splx (s);
   
           if (t->flags & TPEXCEP) {
   errxit:         bp->b_error = EIO;
   err2xit:        bp->b_flags |= B_ERROR;
           }
   xit:    biodone (bp);
           return;
   }
   
   /*
    * Interrupt routine.
    */
   void
   wtintr (int u)
   {
           wtinfo_t *t = wttab + u;
           unsigned char s;
   
           if (u >= NWT || t->type == UNKNOWN) {
                   TRACE (("wtintr() -- device not configured\n"));
                   return;
           }
   
           s = inb (t->STATPORT);                  /* get status */
           TRACE (("wtintr() status=0x%x -- ", s));
           if ((s & (t->BUSY | t->NOEXCEP)) == (t->BUSY | t->NOEXCEP)) {
                   TRACE (("busy\n"));
                   return;                         /* device is busy */
           }
   
           /*
            * Check if rewind finished.
            */
           if (t->flags & TPREW) {
                   TRACE (((s & (t->BUSY | t->NOEXCEP)) == (t->BUSY | t->NOEXCEP) ?
                           "rewind busy?\n" : "rewind finished\n"));
                   t->flags &= ~TPREW;             /* Rewind finished. */
                   wtsense (t, 1, TP_WRP);
                   wakeup ((caddr_t)t);
                   return;
           }
   
           /*
            * Check if writing/reading of file mark finished.
            */
           if (t->flags & (TPRMARK | TPWMARK)) {
                   TRACE (((s & (t->BUSY | t->NOEXCEP)) == (t->BUSY | t->NOEXCEP) ?
                           "marker r/w busy?\n" : "marker r/w finished\n"));
                   if (! (s & t->NOEXCEP))         /* operation failed */
                           wtsense (t, 1, (t->flags & TPRMARK) ? TP_WRP : 0);
                   t->flags &= ~(TPRMARK | TPWMARK); /* operation finished */
                   wakeup ((caddr_t)t);
                   return;
           }
   
           /*
            * Do we started any i/o?  If no, just return.
            */
           if (! (t->flags & TPACTIVE)) {
                   TRACE (("unexpected interrupt\n"));
                   return;
           }
   
           /*
            * Clean up dma.
            */
           if ((t->dmaflags & B_READ) && (t->dmatotal - t->dmacount) < t->bsize) {
                   /* If reading short block, copy the internal buffer
                    * to the user memory. */
                   isa_dmadone (t->dmaflags, t->buf, t->bsize, t->chan);
                   bcopy (t->buf, t->dmavaddr, t->dmatotal - t->dmacount);
           } else
                   isa_dmadone (t->dmaflags, t->dmavaddr, t->bsize, t->chan);
   
           t->flags &= ~TPACTIVE;
           t->dmacount += t->bsize;
           t->dmavaddr = (char *)t->dmavaddr + t->bsize;
   
           /*
            * On exception, check for end of file and end of volume.
            */
           if (! (s & t->NOEXCEP)) {
                   TRACE (("i/o exception\n"));
                   wtsense (t, 1, (t->dmaflags & B_READ) ? TP_WRP : 0);
                   if (t->error.err & (TP_EOM | TP_FIL))
                           t->flags |= TPVOL;      /* end of file */
                   else
                           t->flags |= TPEXCEP;    /* i/o error */
                   wakeup ((caddr_t)t);
                   return;
           }
   
           if (t->dmacount < t->dmatotal) {        /* continue i/o */
                   wtdma (t);
                   TRACE (("continue i/o, %d\n", t->dmacount));
                   return;
           }
           if (t->dmacount > t->dmatotal)          /* short last block */
                   t->dmacount = t->dmatotal;
           wakeup ((caddr_t)t);    /* wake up user level */
           TRACE (("i/o finished, %d\n", t->dmacount));
   }
   
   /* start the rewind operation */
   static void
   wtrewind (wtinfo_t *t)
   {
           int rwmode = (t->flags & (TPRO | TPWO));
   
           t->flags &= ~(TPRO | TPWO | TPVOL);
           /*
            * Wangtek strictly follows QIC-02 standard:
            * clearing ONLINE in read/write modes causes rewind.
            * REWIND command is not allowed in read/write mode
            * and gives `illegal command' error.
            */
           if (t->type==WANGTEK && rwmode) {
                   outb (t->CTLPORT, 0);
           } else if (! wtcmd (t, QIC_REWIND))
                   return;
           t->flags |= TPSTART | TPREW;
           wtclock (t);
   }
   
   /* start the `read marker' operation */
   static int
   wtreadfm (wtinfo_t *t)
   {
           t->flags &= ~(TPRO | TPWO | TPVOL);
           if (! wtcmd (t, QIC_READFM)) {
                   wtsense (t, 1, TP_WRP);
                   return (EIO);
           }
           t->flags |= TPRMARK | TPRANY;
           wtclock (t);
           /* Don't wait for completion here. */
           return (0);
   }
   
   /* write marker to the tape */
   static int
   wtwritefm (wtinfo_t *t)
   {
           tsleep ((caddr_t)wtwritefm, WTPRI, "wtwfm", hz); /* timeout: 1 second */
           t->flags &= ~(TPRO | TPWO);
           if (! wtcmd (t, QIC_WRITEFM)) {
                   wtsense (t, 1, 0);
                   return (EIO);
           }
           t->flags |= TPWMARK | TPWANY;
           wtclock (t);
           return (wtwait (t, 0, "wtwfm"));
   }
   
   /* while controller status & mask == bits continue waiting */
   static int
   wtpoll (wtinfo_t *t, int mask, int bits)
   {
           int s, i;
   
           /* Poll status port, waiting for specified bits. */
           for (i=0; i<1000; ++i) {                        /* up to 1 msec */
                   s = inb (t->STATPORT);
                   if ((s & mask) != bits)
                           return (s);
                   DELAY (1);
           }
           for (i=0; i<100; ++i) {                         /* up to 10 msec */
                   s = inb (t->STATPORT);
                   if ((s & mask) != bits)
                           return (s);
                   DELAY (100);
           }
           for (;;) {                                      /* forever */
                   s = inb (t->STATPORT);
                   if ((s & mask) != bits)
                           return (s);
                   tsleep ((caddr_t)wtpoll, WTPRI, "wtpoll", 1); /* timeout: 1 tick */
           }
   }
   
   /* execute QIC command */
   static int
   wtcmd (wtinfo_t *t, int cmd)
   {
           int s, x;
   
           TRACE (("wtcmd() cmd=0x%x\n", cmd));
           x = splbio();
           s = wtpoll (t, t->BUSY | t->NOEXCEP, t->BUSY | t->NOEXCEP); /* ready? */
           if (! (s & t->NOEXCEP)) {                       /* error */
                   splx(x);
                   return (0);
           }
   
           outb (t->CMDPORT, cmd);                         /* output the command */
   
           outb (t->CTLPORT, t->REQUEST | t->ONLINE);      /* set request */
           wtpoll (t, t->BUSY, t->BUSY);                   /* wait for ready */
           outb (t->CTLPORT, t->IEN | t->ONLINE);          /* reset request */
           wtpoll (t, t->BUSY, 0);                         /* wait for not ready */
           splx(x);
           return (1);
   }
   
   /* wait for the end of i/o, seeking marker or rewind operation */
   static int
   wtwait (wtinfo_t *t, int catch, char *msg)
   {
           int error;
   
           TRACE (("wtwait() `%s'\n", msg));
           while (t->flags & (TPACTIVE | TPREW | TPRMARK | TPWMARK))
                   if (error = tsleep ((caddr_t)t, WTPRI | catch, msg, 0))
                           return (error);
           return (0);
   }
   
   /* initialize dma for the i/o operation */
   static void
   wtdma (wtinfo_t *t)
   {
           t->flags |= TPACTIVE;
           wtclock (t);
   
           if (t->type == ARCHIVE)
                   outb (t->SDMAPORT, 0);          /* set dma */
   
           if ((t->dmaflags & B_READ) && (t->dmatotal - t->dmacount) < t->bsize)
                   /* Reading short block.  Do it through the internal buffer. */
                   isa_dmastart (t->dmaflags, t->buf, t->bsize, t->chan);
           else
                   isa_dmastart (t->dmaflags, t->dmavaddr, t->bsize, t->chan);
   }
   
   /* start i/o operation */
   static int
   wtstart (wtinfo_t *t, unsigned flags, void *vaddr, unsigned len)
   {
           int s, x;
   
           TRACE (("wtstart()\n"));
           x = splbio();
           s = wtpoll (t, t->BUSY | t->NOEXCEP, t->BUSY | t->NOEXCEP); /* ready? */
           if (! (s & t->NOEXCEP)) {
                   t->flags |= TPEXCEP;            /* error */
                   splx(x);
                   return (0);
           }
           t->flags &= ~TPEXCEP;                   /* clear exception flag */
           t->dmavaddr = vaddr;
           t->dmatotal = len;
           t->dmacount = 0;
           t->dmaflags = flags;
           wtdma (t);
           splx(x);
           return (1);
   }
   
   /* start timer */
   static void
   wtclock (wtinfo_t *t)
   {
           if (! (t->flags & TPTIMER)) {
                   t->flags |= TPTIMER;
                   /* Some controllers seem to lose dma interrupts too often.
                    * To make the tape stream we need 1 tick timeout. */
                   timeout (wtimer, (caddr_t)t, (t->flags & TPACTIVE) ? 1 : hz);
           }
   }
   
   /*
    * Simulate an interrupt periodically while i/o is going.
    * This is necessary in case interrupts get eaten due to
    * multiple devices on a single IRQ line.
    */
   static void
   wtimer (void *xt)
   {
           wtinfo_t *t = (wtinfo_t *)xt;
           int s;
   
           t->flags &= ~TPTIMER;
           if (! (t->flags & (TPACTIVE | TPREW | TPRMARK | TPWMARK)))
                   return;
   
           /* If i/o going, simulate interrupt. */
           s = splbio ();
           if ((inb (t->STATPORT) & (t->BUSY | t->NOEXCEP)) != (t->BUSY | t->NOEXCEP)) {
                   TRACE (("wtimer() -- "));
                   wtintr (t->unit);
           }
           splx (s);
   
           /* Restart timer if i/o pending. */
           if (t->flags & (TPACTIVE | TPREW | TPRMARK | TPWMARK))
                   wtclock (t);
   }
   
   /* reset the controller */
   static int
   wtreset (wtinfo_t *t)
   {
           /* Perform QIC-02 and QIC-36 compatible reset sequence. */
           /* Thanks to Mikael Hybsch <micke@dynas.se>. */
           int s, i;
   
           outb (t->CTLPORT, t->RESET | t->ONLINE); /* send reset */
           DELAY (30);
           outb (t->CTLPORT, t->ONLINE);           /* turn off reset */
           DELAY (30);
   
           /* Read the controller status. */
           s = inb (t->STATPORT);
           if (s == 0xff)                          /* no port at this address? */
                   return (0);
   
           /* Wait 3 sec for reset to complete. Needed for QIC-36 boards? */
           for (i=0; i<3000; ++i) {
                   if (! (s & t->BUSY) || ! (s & t->NOEXCEP))
                           break;
                   DELAY (1000);
                   s = inb (t->STATPORT);
           }
           return ((s & t->RESETMASK) == t->RESETVAL);
   }
   
   /* get controller status information */
   /* return 0 if user i/o request should receive an i/o error code */
   static int
   wtsense (wtinfo_t *t, int verb, int ignor)
   {
           char *msg = 0;
           int err;
   
           TRACE (("wtsense() ignor=0x%x\n", ignor));
           t->flags &= ~(TPRO | TPWO);
           if (! wtstatus (t))
                   return (0);
           if (! (t->error.err & TP_ST0))
                   t->error.err &= ~TP_ST0MASK;
           if (! (t->error.err & TP_ST1))
                   t->error.err &= ~TP_ST1MASK;
           t->error.err &= ~ignor;         /* ignore certain errors */
           err = t->error.err & (TP_FIL | TP_BNL | TP_UDA | TP_EOM | TP_WRP |
                   TP_USL | TP_CNI | TP_MBD | TP_NDT | TP_ILL);
           if (! err)
                   return (1);
           if (! verb)
                   return (0);
   
           /* lifted from tdriver.c from Wangtek */
           if      (err & TP_USL)  msg = "Drive not online";
           else if (err & TP_CNI)  msg = "No cartridge";
           else if ((err & TP_WRP) && !(t->flags & TPWP)) {
                   msg = "Tape is write protected";
                   t->flags |= TPWP;
           }
           else if (err & TP_FIL)  msg = 0 /*"Filemark detected"*/;
           else if (err & TP_EOM)  msg = 0 /*"End of tape"*/;
           else if (err & TP_BNL)  msg = "Block not located";
           else if (err & TP_UDA)  msg = "Unrecoverable data error";
           else if (err & TP_NDT)  msg = "No data detected";
           else if (err & TP_ILL)  msg = "Illegal command";
           if (msg)
                   printf ("wt%d: %s\n", t->unit, msg);
           return (0);
   }
   
   /* get controller status information */
   static int
   wtstatus (wtinfo_t *t)
   {
           char *p;
           int x;
   
           x = splbio();
           wtpoll (t, t->BUSY | t->NOEXCEP, t->BUSY | t->NOEXCEP); /* ready? */
           outb (t->CMDPORT, QIC_RDSTAT);  /* send `read status' command */
   
           outb (t->CTLPORT, t->REQUEST | t->ONLINE);      /* set request */
           wtpoll (t, t->BUSY, t->BUSY);                   /* wait for ready */
           outb (t->CTLPORT, t->ONLINE);                   /* reset request */
           wtpoll (t, t->BUSY, 0);                         /* wait for not ready */
   
           p = (char*) &t->error;
           while (p < (char*)&t->error + 6) {
                   int s = wtpoll (t, t->BUSY | t->NOEXCEP, t->BUSY | t->NOEXCEP);
                   if (! (s & t->NOEXCEP)) {               /* error */
                           splx(x);
                           return (0);
                   }
   
                   *p++ = inb (t->DATAPORT);               /* read status byte */
   
                   outb (t->CTLPORT, t->REQUEST | t->ONLINE); /* set request */
                   wtpoll (t, t->BUSY, 0);                 /* wait for not ready */
                   DELAY(20);
                   outb (t->CTLPORT, t->ONLINE);           /* unset request */
           }
           splx(x);
           return (1);
   }
   
   
   static wt_devsw_installed = 0;
   
   static void 
   wt_drvinit(void *unused)
   {
   
           if( ! wt_devsw_installed ) {
                   bdevsw_add_generic(BDEV_MAJOR,CDEV_MAJOR, &wt_bdevsw);
                   wt_devsw_installed = 1;
           }
   }
  
  SYSINIT(wtdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,wt_drvinit,NULL)
  
  
  #endif /* NWT */

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