aboutsummaryrefslogtreecommitdiff
path: root/sys/i386/isa/gsc.c
blob: 8d7ded32384ae8922e9b31f1c3dd98fcb8d13ba9 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
/* gsc.c - device driver for handy scanners
 *
 * Current version supports:
 *
 * 	- Genius GS-4500
 *
 * Copyright (c) 1995 Gunther Schadow.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by Gunther Schadow.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * $FreeBSD$
 *
 */

#include "gsc.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/uio.h>
#include <sys/bus.h>

#include <machine/gsc.h>

#include <i386/isa/isa.h>
#include <i386/isa/isa_device.h>
#include <i386/isa/gscreg.h>

#ifndef COMPAT_OLDISA
#error "The gsc device requires the old isa compatibility shims"
#endif

/***********************************************************************
 *
 * CONSTANTS & DEFINES
 *
 ***********************************************************************/

#define PROBE_FAIL    0
#define PROBE_SUCCESS IO_GSCSIZE
#define ATTACH_FAIL   0
#define ATTACH_SUCCESS 1
#define SUCCESS       0
#define FAIL         -1
#define INVALID       FAIL

#define DMA1_READY  0x08

#ifdef GSCDEBUG
#define lprintf(args)						\
		do {						\
			if (scu->flags & FLAG_DEBUG)		\
				printf args;			\
		} while (0)
#else
#define lprintf(args)
#endif

#define MIN(a, b)	(((a) < (b)) ? (a) : (b))

#define TIMEOUT (hz*15)  /* timeout while reading a buffer - default value */
#define LONG    (hz/60)  /* timesteps while reading a buffer */
#define GSCPRI  PRIBIO   /* priority while reading a buffer */

/***********************************************************************
 *
 * LAYOUT OF THE MINOR NUMBER
 *
 ***********************************************************************/

#define UNIT_MASK 0xc0    /* unit gsc0 .. gsc3 */
#define UNIT(x)   (x >> 6)
#define DBUG_MASK 0x20
#define FRMT_MASK 0x18    /* output format */
#define FRMT_RAW  0x00    /* output bits as read from scanner */
#define FRMT_GRAY 0x10    /* output graymap (not implemented yet) */
#define FRMT_PBM  0x08    /* output pbm format */
#define FRMT_PGM  0x18

/***********************************************************************
 *
 * THE GEMOMETRY TABLE
 *
 ***********************************************************************/

#define GEOMTAB_SIZE 7

static const struct gsc_geom {
  int dpi;     /* dots per inch */
  int dpl;     /* dots per line */
  int g_res;   /* get resolution value (status flag) */
  int s_res;   /* set resolution value (control register) */
} geomtab[GEOMTAB_SIZE] = {
  { 100,  424, GSC_RES_100, GSC_CNT_424},
  { 200,  840, GSC_RES_200, GSC_CNT_840},
  { 300, 1264, GSC_RES_300, GSC_CNT_1264},
  { 400, 1648, GSC_RES_400, GSC_CNT_1648},
  {  -1, 1696,          -1, GSC_CNT_1696},
  {  -2, 2644,          -2, GSC_CNT_2544},
  {  -3, 3648,          -3, GSC_CNT_3648},
};

#define NEW_GEOM { INVALID, INVALID, INVALID, INVALID }

/***********************************************************************
 *
 * THE TABLE OF UNITS
 *
 ***********************************************************************/

struct _sbuf {
  size_t  size;
  size_t  poi;
  char   *base;
};

struct gsc_unit {
  int channel;            /* DMA channel */
  int data;               /* - video port */
  int stat;               /* - status port */
  int ctrl;               /* - control port */
  int clrp;               /* - clear port */
  int flags;
#define ATTACHED 0x01
#define OPEN     0x02
#define READING  0x04
#define EOF      0x08
#define FLAG_DEBUG  0x10
#define PBM_MODE 0x20
  int     geometry;       /* resolution as geomtab index */
  int     blen;           /* length of buffer in lines */
  int     btime;          /* timeout of buffer in seconds/hz */
  struct  _sbuf sbuf;
  char    ctrl_byte;      /* the byte actually written to ctrl port */
  int     height;         /* height, for pnm modes */
  size_t  bcount;         /* bytes to read, for pnm modes */
  struct  _sbuf hbuf;     /* buffer for pnm header data */
};

static struct gsc_unit unittab[NGSC];

/* I could not find a reasonable buffer size limit other than by
 * experiments. MAXPHYS is obviously too much, while DEV_BSIZE and
 * PAGE_SIZE are really too small. There must be something wrong
 * with isa_dmastart/isa_dmarangecheck HELP!!!
 */
#define MAX_BUFSIZE 0x3000
#define DEFAULT_BLEN 59

/***********************************************************************
 *
 * THE PER-DRIVER RECORD FOR ISA.C
 *
 ***********************************************************************/

static	int gscprobe (struct isa_device *isdp);
static	int gscattach(struct isa_device *isdp);

struct isa_driver gscdriver = {
	INTR_TYPE_TTY,
	gscprobe,
	gscattach,
	"gsc"
};
COMPAT_ISA_DRIVER(gsc, gscdriver);

static	d_open_t	gscopen;
static	d_close_t	gscclose;
static	d_read_t	gscread;
static	d_ioctl_t	gscioctl;

#define CDEV_MAJOR 47
static struct cdevsw gsc_cdevsw = {
	/* open */	gscopen,
	/* close */	gscclose,
	/* read */	gscread,
	/* write */	nowrite,
	/* ioctl */	gscioctl,
	/* poll */	nopoll,
	/* mmap */	nommap,
	/* strategy */	nostrategy,
	/* name */	"gsc",
	/* maj */	CDEV_MAJOR,
	/* dump */	nodump,
	/* psize */	nopsize,
	/* flags */	0,
};


/***********************************************************************
 *
 * LOCALLY USED SUBROUTINES
 *
 ***********************************************************************/

/***********************************************************************
 *
 * lookup_geometry -- lookup a record in the geometry table by pattern
 *
 * The caller supplies a geometry record pattern, where INVALID
 * matches anything. Returns the index in the table or INVALID if
 * lookup fails.
 */

static int
lookup_geometry(struct gsc_geom geom, const struct gsc_unit *scu)
{
  struct gsc_geom tab;
  int i;

  for(i=0; i<GEOMTAB_SIZE; i++)
    {
      tab = geomtab[i];

      if ( ( ( geom.dpi   != INVALID ) && ( tab.dpi   == geom.dpi   ) ) ||
	   ( ( geom.dpl   != INVALID ) && ( tab.dpl   == geom.dpl   ) ) ||
	   ( ( geom.g_res != INVALID ) && ( tab.g_res == geom.g_res ) ) ||
	   ( ( geom.s_res != INVALID ) && ( tab.s_res == geom.s_res ) ) )
	{
	  lprintf(("gsc.lookup_geometry: "
		 "geometry lookup found: %ddpi, %ddpl\n",
		 tab.dpi, tab.dpl));
	  return i;
	}
    }

  lprintf(("gsc.lookup_geometry: "
	 "geometry lookup failed on {%d, %d, 0x%02x, 0x%02x}\n",
	 geom.dpi, geom.dpl, geom.g_res, geom.s_res));

  return INVALID;
}

/***********************************************************************
 *
 * get_geometry -- read geometry from status port
 *
 * Returns the index into geometry table or INVALID if it fails to
 * either read the status byte or lookup the record.
 */

static int
get_geometry(const struct gsc_unit *scu)
{
  struct gsc_geom geom = NEW_GEOM;

  lprintf(("gsc.get_geometry: get geometry at 0x%03x\n", scu->stat));

  if ( ( geom.g_res = inb(scu->stat) ) == FAIL )
    return INVALID;

  geom.g_res &= GSC_RES_MASK;

  return lookup_geometry(geom, scu);
}

/***********************************************************************
 *
 * buffer_allocate -- allocate/reallocate a buffer
 * Now just checks that the preallocated buffer is large enough.
 */

static int
buffer_allocate(struct gsc_unit *scu)
{
  size_t size;

  size = scu->blen * geomtab[scu->geometry].dpl / 8;

  lprintf(("gsc.buffer_allocate: need 0x%x bytes\n", size));

  if ( size > MAX_BUFSIZE )
    {
      lprintf(("gsc.buffer_allocate: 0x%x bytes are too much\n", size));
      return ENOMEM;
    }

  scu->sbuf.size = size;
  scu->sbuf.poi  = size;

  lprintf(("gsc.buffer_allocate: ok\n"));

  return SUCCESS;
}

/***********************************************************************
 *
 * buffer_read -- scan a buffer
 */

static int
buffer_read(struct gsc_unit *scu)
{
  int stb;
  int res = SUCCESS;
  int chan_bit;
  char *p;
  int sps;
  int delay;

  lprintf(("gsc.buffer_read: begin\n"));

  if (scu->ctrl_byte == INVALID)
    {
      lprintf(("gsc.buffer_read: invalid ctrl_byte\n"));
      return EIO;
    }

  sps=splbio();

  outb( scu->ctrl, scu->ctrl_byte | GSC_POWER_ON );
  outb( scu->clrp, 0 );
  stb = inb( scu->stat );

  isa_dmastart(ISADMA_READ, scu->sbuf.base, scu->sbuf.size, scu->channel);

  chan_bit = 0x01 << scu->channel;

  for(delay=0; !(inb(DMA1_READY) & 0x01 << scu->channel); delay += LONG)
    {
      if(delay >= scu->btime)
	{
	  splx(sps);
	  lprintf(("gsc.buffer_read: timeout\n"));
	  res = EWOULDBLOCK;
	  break;
	}
      res = tsleep((caddr_t)scu, GSCPRI | PCATCH, "gscread", LONG);
      if ( ( res == 0 ) || ( res == EWOULDBLOCK ) )
	res = SUCCESS;
      else
	break;
    }
  splx(sps);
  isa_dmadone(ISADMA_READ, scu->sbuf.base, scu->sbuf.size, scu->channel);
  outb( scu->clrp, 0 );

  if(res != SUCCESS)
    {
      lprintf(("gsc.buffer_read: aborted with %d\n", res));
      return res;
    }

  lprintf(("gsc.buffer_read: invert buffer\n"));
  for(p = scu->sbuf.base + scu->sbuf.size - 1; p >= scu->sbuf.base; p--)
    *p = ~*p;

  scu->sbuf.poi = 0;
  lprintf(("gsc.buffer_read: ok\n"));
  return SUCCESS;
}

/***********************************************************************
 *
 * the main functions
 *
 ***********************************************************************/

/***********************************************************************
 *
 * gscprobe
 *
 * read status port and check for proper configuration:
 *  - if address group matches (status byte has reasonable value)
 *  - if DMA channel matches   (status byte has correct value)
 */

static int
gscprobe (struct isa_device *isdp)
{
  int unit = isdp->id_unit;
  struct gsc_unit *scu = unittab + unit;
  int stb;
  struct gsc_geom geom = NEW_GEOM;
  static int once;

  if (!once++)
	cdevsw_add(&gsc_cdevsw);

  scu->flags = FLAG_DEBUG;

  lprintf(("gsc%d.probe "
	 "on iobase 0x%03x, irq %d, drq %d, addr %p, size %d\n",
	 unit,
	 isdp->id_iobase,
	 isdp->id_irq,
	 isdp->id_drq,
	 isdp->id_maddr,
	 isdp->id_msize));

  if ( isdp->id_iobase < 0 )
    {
      lprintf(("gsc%d.probe: no iobase given\n", unit));
      return PROBE_FAIL;
    }

  stb = inb( GSC_STAT(isdp->id_iobase) );
  if (stb == FAIL)
    {
      lprintf(("gsc%d.probe: get status byte failed\n", unit));
      return PROBE_FAIL;
    }

  scu->data = GSC_DATA(isdp->id_iobase);
  scu->stat = GSC_STAT(isdp->id_iobase);
  scu->ctrl = GSC_CTRL(isdp->id_iobase);
  scu->clrp = GSC_CLRP(isdp->id_iobase);

  outb(scu->clrp,stb);
  stb = inb(scu->stat);

  switch(stb & GSC_CNF_MASK) {
  case GSC_CNF_DMA1:
    lprintf(("gsc%d.probe: DMA 1\n", unit));
    scu->channel = 1;
    break;

  case GSC_CNF_DMA3:
    lprintf(("gsc%d.probe: DMA 3\n", unit));
    scu->channel = 3;
    break;

  case GSC_CNF_IRQ3:
    lprintf(("gsc%d.probe: IRQ 3\n", unit));
    goto probe_noirq;
  case GSC_CNF_IRQ5:
    lprintf(("gsc%d.probe: IRQ 5\n", unit));
  probe_noirq:
    lprintf(("gsc%d.probe: sorry, can't use IRQ yet\n", unit));
    return PROBE_FAIL;
  default:
    lprintf(("gsc%d.probe: invalid status byte 0x%02x\n", unit, (u_char) stb));
    return PROBE_FAIL;
  }

  if (isdp->id_drq < 0)
    isdp->id_drq = scu->channel;
  if (scu->channel != isdp->id_drq)
    {
      lprintf(("gsc%d.probe: drq mismatch: config: %d; hardware: %d\n",
	      unit, isdp->id_drq, scu->channel));
      return PROBE_FAIL;
    }

  geom.g_res = stb & GSC_RES_MASK;
  scu->geometry = lookup_geometry(geom, scu);
  if (scu->geometry == INVALID)
    {
      lprintf(("gsc%d.probe: geometry lookup failed\n", unit));
      return PROBE_FAIL;
    }
  else
    {
      scu->ctrl_byte = geomtab[scu->geometry].s_res;
      outb(scu->ctrl, scu->ctrl_byte | GSC_POWER_ON);

      lprintf(("gsc%d.probe: status 0x%02x, %ddpi\n",
	     unit, stb, geomtab[scu->geometry].dpi));

      outb(scu->ctrl, scu->ctrl_byte & ~GSC_POWER_ON);
    }

  lprintf(("gsc%d.probe: ok\n", unit));

  scu->flags &= ~FLAG_DEBUG;

  return PROBE_SUCCESS;
}

/***********************************************************************
 *
 * gscattach
 *
 * finish initialization of unit structure
 * get geometry value
 */

static int
gscattach(struct isa_device *isdp)
{
  int unit = isdp->id_unit;
  struct gsc_unit *scu = unittab + unit;

  scu->flags |= FLAG_DEBUG;

  lprintf(("gsc%d.attach: "
	 "iobase 0x%03x, irq %d, drq %d, addr %p, size %d\n",
	 unit,
	 isdp->id_iobase,
	 isdp->id_irq,
	 isdp->id_drq,
	 isdp->id_maddr,
	 isdp->id_msize));

  printf("gsc%d: GeniScan GS-4500 at %ddpi\n",
	 unit, geomtab[scu->geometry].dpi);

  /*
   * Initialize buffer structure.
   * XXX this must be done early to give a good chance of getting a
   * contiguous buffer.  This wastes memory.
   */
  scu->sbuf.base = contigmalloc((unsigned long)MAX_BUFSIZE, M_DEVBUF, M_NOWAIT,
				0ul, 0xfffffful, 1ul, 0x10000ul);
  if ( scu->sbuf.base == NULL )
    {
      lprintf(("gsc%d.attach: buffer allocation failed\n", unit));
      return ATTACH_FAIL;	/* XXX attach must not fail */
    }
  scu->sbuf.size = INVALID;
  scu->sbuf.poi  = INVALID;

  scu->blen = DEFAULT_BLEN;
  scu->btime = TIMEOUT;

  scu->flags |= ATTACHED;
  lprintf(("gsc%d.attach: ok\n", unit));
  scu->flags &= ~FLAG_DEBUG;
#define GSC_UID 0
#define GSC_GID 13
  make_dev(&gsc_cdevsw, unit<<6, GSC_UID, GSC_GID, 0666, "gsc%d", unit);
  make_dev(&gsc_cdevsw, ((unit<<6) + FRMT_PBM),
     GSC_UID,  GSC_GID, 0666, "gsc%dp", unit);
  make_dev(&gsc_cdevsw, ((unit<<6) + DBUG_MASK),
     GSC_UID,  GSC_GID, 0666, "gsc%dd", unit);
  make_dev(&gsc_cdevsw, ((unit<<6) + DBUG_MASK+FRMT_PBM),
     GSC_UID,  GSC_GID, 0666, "gsc%dpd", unit);

  return ATTACH_SUCCESS;
}

/***********************************************************************
 *
 * gscopen
 *
 * set open flag
 * set modes according to minor number
 * don't switch scanner on, wait until first read ioctls go before
 */

static	int
gscopen  (dev_t dev, int flags, int fmt, struct proc *p)
{
  struct gsc_unit *scu;
  int unit;

  unit = UNIT(minor(dev)) & UNIT_MASK;
  if ( unit >= NGSC )
    {
#ifdef GSCDEBUG
      /* XXX lprintf isn't valid here since there is no scu. */
      printf("gsc%d.open: unconfigured unit number (max %d)\n", unit, NGSC);
#endif
      return ENXIO;
    }
  scu = unittab + unit;
  if ( !( scu->flags & ATTACHED ) )
    {
      lprintf(("gsc%d.open: unit was not attached successfully 0x%04x\n",
	     unit, scu->flags));
      return ENXIO;
    }

  if ( minor(dev) & DBUG_MASK )
    scu->flags |= FLAG_DEBUG;
  else
    scu->flags &= ~FLAG_DEBUG;

  switch(minor(dev) & FRMT_MASK) {
  case FRMT_PBM:
    scu->flags |= PBM_MODE;
    lprintf(("gsc%d.open: pbm mode\n", unit));
    break;
  case FRMT_RAW:
    lprintf(("gsc%d.open: raw mode\n", unit));
    scu->flags &= ~PBM_MODE;
    break;
  default:
    lprintf(("gsc%d.open: gray maps are not yet supported", unit));
    return ENXIO;
  }

  lprintf(("gsc%d.open: minor %d\n",
	 unit, minor(dev)));

  if ( scu->flags & OPEN )
    {
      lprintf(("gsc%d.open: already open", unit));
      return EBUSY;
    }

  if (isa_dma_acquire(scu->channel))
      return(EBUSY);

  scu->flags |= OPEN;

  return SUCCESS;
}

/***********************************************************************
 *
 * gscclose
 *
 * turn off scanner
 * release the buffer
 */

static	int
gscclose (dev_t dev, int flags, int fmt, struct proc *p)
{
  int unit = UNIT(minor(dev));
  struct gsc_unit *scu = unittab + unit;

  lprintf(("gsc%d.close: minor %d\n",
	 unit, minor(dev)));

  if ( unit >= NGSC || !( scu->flags & ATTACHED ) )
    {
      lprintf(("gsc%d.read: unit was not attached successfully 0x%04x\n",
	     unit, scu->flags));
      return ENXIO;
    }

  outb(scu->ctrl, scu->ctrl_byte & ~GSC_POWER_ON);

  scu->sbuf.size = INVALID;
  scu->sbuf.poi  = INVALID;

  isa_dma_release(scu->channel);

  scu->flags &= ~(FLAG_DEBUG | OPEN | READING);

  return SUCCESS;
}

/***********************************************************************
 *
 * gscread
 */

static	int
gscread  (dev_t dev, struct uio *uio, int ioflag)
{
  int unit = UNIT(minor(dev));
  struct gsc_unit *scu = unittab + unit;
  size_t nbytes;
  int res;

  lprintf(("gsc%d.read: minor %d\n", unit, minor(dev)));

  if ( unit >= NGSC || !( scu->flags & ATTACHED ) )
    {
      lprintf(("gsc%d.read: unit was not attached successfully 0x%04x\n",
	     unit, scu->flags));
      return ENXIO;
    }

  if ( !(scu->flags & READING) )
    {
      res = buffer_allocate(scu);
      if ( res == SUCCESS )
	scu->flags |= READING;
      else
	return res;

      scu->ctrl_byte = geomtab[scu->geometry].s_res;

      /* initialize for pbm mode */
      if ( scu->flags & PBM_MODE )
	{
	  char *p;
	  int width = geomtab[scu->geometry].dpl;

	  sprintf(scu->sbuf.base,"P4 %d %d\n", width, scu->height);
	  scu->bcount = scu->height * width / 8;

	  lprintf(("gsc%d.read: initializing pbm mode: `%s', bcount: 0x%x\n",
		  unit, scu->sbuf.base, scu->bcount));

	  /* move header to end of sbuf */
	  for(p=scu->sbuf.base; *p; p++);
	  while(--p >= scu->sbuf.base)
	    {
	      *(char *)(scu->sbuf.base + --scu->sbuf.poi) = *p;
	      scu->bcount++;
	    }
	}
    }

  lprintf(("gsc%d.read(before buffer_read): "
	  "size 0x%x, pointer 0x%x, bcount 0x%x, ok\n",
	  unit, scu->sbuf.size, scu->sbuf.poi, scu->bcount));

  if ( scu->sbuf.poi == scu->sbuf.size )
    if ( (res = buffer_read(scu)) != SUCCESS )
      return res;

  lprintf(("gsc%d.read(after buffer_read): "
	  "size 0x%x, pointer 0x%x, bcount 0x%x, ok\n",
	  unit, scu->sbuf.size, scu->sbuf.poi, scu->bcount));

  nbytes = MIN( uio->uio_resid, scu->sbuf.size - scu->sbuf.poi );

  if ( (scu->flags & PBM_MODE) )
    nbytes = MIN( nbytes, scu->bcount );

  lprintf(("gsc%d.read: transferring 0x%x bytes", unit, nbytes));

  res = uiomove(scu->sbuf.base + scu->sbuf.poi, nbytes, uio);
  if ( res != SUCCESS )
    {
      lprintf(("gsc%d.read: uiomove failed %d", unit, res));
      return res;
    }

  scu->sbuf.poi += nbytes;
  if ( scu->flags & PBM_MODE ) scu->bcount -= nbytes;

  lprintf(("gsc%d.read: size 0x%x, pointer 0x%x, bcount 0x%x, ok\n",
	  unit, scu->sbuf.size, scu->sbuf.poi, scu->bcount));

  return SUCCESS;
}

/***********************************************************************
 *
 * gscioctl
 *
 */

static	int
gscioctl (dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
{
  int unit = UNIT(minor(dev));
  struct gsc_unit *scu = unittab + unit;

  lprintf(("gsc%d.ioctl: minor %d\n",
	 unit, minor(dev)));

  if ( unit >= NGSC || !( scu->flags & ATTACHED ) )
    {
      lprintf(("gsc%d.ioctl: unit was not attached successfully 0x%04x\n",
	     unit, scu->flags));
      return ENXIO;
    }

  switch(cmd) {
  case GSC_SRESSW:
    lprintf(("gsc%d.ioctl:GSC_SRESSW\n", unit));
    if ( scu->flags & READING )
      {
	lprintf(("gsc%d:ioctl on already reading unit\n", unit));
	return EBUSY;
      }
    scu->geometry = get_geometry(scu);
    return SUCCESS;
  case GSC_GRES:
    *(int *)data=geomtab[scu->geometry].dpi;
    lprintf(("gsc%d.ioctl:GSC_GRES %ddpi\n", unit, *(int *)data));
    return SUCCESS;
  case GSC_GWIDTH:
    *(int *)data=geomtab[scu->geometry].dpl;
    lprintf(("gsc%d.ioctl:GSC_GWIDTH %d\n", unit, *(int *)data));
    return SUCCESS;
  case GSC_SRES:
  case GSC_SWIDTH:
    lprintf(("gsc%d.ioctl:GSC_SRES or GSC_SWIDTH %d\n",
	   unit, *(int *)data));
    { int g;
      struct gsc_geom geom = NEW_GEOM;
      if ( cmd == GSC_SRES )
	geom.dpi = *(int *)data;
      else
	geom.dpl = *(int *)data;
      if ( ( g = lookup_geometry(geom, scu) ) == INVALID )
	return EINVAL;
      scu->geometry = g;
      return SUCCESS;
    }
  case GSC_GHEIGHT:
    *(int *)data=scu->height;
    lprintf(("gsc%d.ioctl:GSC_GHEIGHT %d\n", unit, *(int *)data));
    return SUCCESS;
  case GSC_SHEIGHT:
    lprintf(("gsc%d.ioctl:GSC_SHEIGHT %d\n", unit, *(int *)data));
    if ( scu->flags & READING )
      {
	lprintf(("gsc%d:ioctl on already reading unit\n", unit));
	return EBUSY;
      }
    scu->height=*(int *)data;
    return SUCCESS;
  case GSC_GBLEN:
    *(int *)data=scu->blen;
    lprintf(("gsc%d.ioctl:GSC_GBLEN %d\n", unit, *(int *)data));
    return SUCCESS;
  case GSC_SBLEN:
    lprintf(("gsc%d.ioctl:GSC_SBLEN %d\n", unit, *(int *)data));
    if (*(int *)data * geomtab[scu->geometry].dpl / 8 > MAX_BUFSIZE)
      {
	lprintf(("gsc%d:ioctl buffer size too high\n", unit));
	return ENOMEM;
      }
    scu->blen=*(int *)data;
    return SUCCESS;
  case GSC_GBTIME:
    *(int *)data = scu->btime / hz;
    lprintf(("gsc%d.ioctl:GSC_GBTIME %d\n", unit, *(int *)data));
    return SUCCESS;
  case GSC_SBTIME:
    scu->btime = *(int *)data * hz;
    lprintf(("gsc%d.ioctl:GSC_SBTIME %d\n", unit, *(int *)data));
    return SUCCESS;
  default: return ENOTTY;
  }
}