Free Electrons

Embedded Linux Experts

  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
/* 
	pg.c    (c) 1998  Grant R. Guenther <grant@torque.net>
			  Under the terms of the GNU General Public License.

	The pg driver provides a simple character device interface for
	sending ATAPI commands to a device.  With the exception of the
	ATAPI reset operation, all operations are performed by a pair
	of read and write operations to the appropriate /dev/pgN device.
	A write operation delivers a command and any outbound data in
	a single buffer.  Normally, the write will succeed unless the
	device is offline or malfunctioning, or there is already another
	command pending.  If the write succeeds, it should be followed
	immediately by a read operation, to obtain any returned data and
	status information.  A read will fail if there is no operation
	in progress.

	As a special case, the device can be reset with a write operation,
	and in this case, no following read is expected, or permitted.

	There are no ioctl() operations.  Any single operation
	may transfer at most PG_MAX_DATA bytes.  Note that the driver must
	copy the data through an internal buffer.  In keeping with all
	current ATAPI devices, command packets are assumed to be exactly
	12 bytes in length.

	To permit future changes to this interface, the headers in the
	read and write buffers contain a single character "magic" flag.
	Currently this flag must be the character "P".

	By default, the driver will autoprobe for a single parallel
	port ATAPI device, but if their individual parameters are
	specified, the driver can handle up to 4 devices.

	To use this device, you must have the following device 
	special files defined:

		/dev/pg0 c 97 0
		/dev/pg1 c 97 1
		/dev/pg2 c 97 2
		/dev/pg3 c 97 3

	(You'll need to change the 97 to something else if you use
	the 'major' parameter to install the driver on a different
	major number.)

	The behaviour of the pg driver can be altered by setting
	some parameters from the insmod command line.  The following
	parameters are adjustable:

	    drive0      These four arguments can be arrays of       
	    drive1      1-6 integers as follows:
	    drive2
	    drive3      <prt>,<pro>,<uni>,<mod>,<slv>,<dly>

			Where,

		<prt>   is the base of the parallel port address for
			the corresponding drive.  (required)

		<pro>   is the protocol number for the adapter that
			supports this drive.  These numbers are
			logged by 'paride' when the protocol modules
			are initialised.  (0 if not given)

		<uni>   for those adapters that support chained
			devices, this is the unit selector for the
			chain of devices on the given port.  It should
			be zero for devices that don't support chaining.
			(0 if not given)

		<mod>   this can be -1 to choose the best mode, or one
			of the mode numbers supported by the adapter.
			(-1 if not given)

		<slv>   ATAPI devices can be jumpered to master or slave.
			Set this to 0 to choose the master drive, 1 to
			choose the slave, -1 (the default) to choose the
			first drive found.

		<dly>   some parallel ports require the driver to 
			go more slowly.  -1 sets a default value that
			should work with the chosen protocol.  Otherwise,
			set this to a small integer, the larger it is
			the slower the port i/o.  In some cases, setting
			this to zero will speed up the device. (default -1)

	    major	You may use this parameter to overide the
			default major number (97) that this driver
			will use.  Be sure to change the device
			name as well.

	    name	This parameter is a character string that
			contains the name the kernel will use for this
			device (in /proc output, for instance).
			(default "pg").

	    verbose     This parameter controls the amount of logging
			that is done by the driver.  Set it to 0 for 
			quiet operation, to 1 to enable progress
			messages while the driver probes for devices,
			or to 2 for full debug logging.  (default 0)

	If this driver is built into the kernel, you can use 
	the following command line parameters, with the same values
	as the corresponding module parameters listed above:

	    pg.drive0
	    pg.drive1
	    pg.drive2
	    pg.drive3

	In addition, you can use the parameter pg.disable to disable
	the driver entirely.

*/

/* Changes:

	1.01	GRG 1998.06.16	Bug fixes
	1.02    GRG 1998.09.24  Added jumbo support

*/

#define PG_VERSION      "1.02"
#define PG_MAJOR	97
#define PG_NAME		"pg"
#define PG_UNITS	4

#ifndef PI_PG
#define PI_PG	4
#endif

/* Here are things one can override from the insmod command.
   Most are autoprobed by paride unless set here.  Verbose is 0
   by default.

*/

static int verbose = 0;
static int major = PG_MAJOR;
static char *name = PG_NAME;
static int disable = 0;

static int drive0[6] = { 0, 0, 0, -1, -1, -1 };
static int drive1[6] = { 0, 0, 0, -1, -1, -1 };
static int drive2[6] = { 0, 0, 0, -1, -1, -1 };
static int drive3[6] = { 0, 0, 0, -1, -1, -1 };

static int (*drives[4])[6] = {&drive0, &drive1, &drive2, &drive3};
static int pg_drive_count;

enum {D_PRT, D_PRO, D_UNI, D_MOD, D_SLV, D_DLY};

/* end of parameters */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/mtio.h>
#include <linux/pg.h>
#include <linux/device.h>
#include <linux/sched.h>	/* current, TASK_* */
#include <linux/mutex.h>
#include <linux/jiffies.h>

#include <asm/uaccess.h>

module_param(verbose, bool, 0644);
module_param(major, int, 0);
module_param(name, charp, 0);
module_param_array(drive0, int, NULL, 0);
module_param_array(drive1, int, NULL, 0);
module_param_array(drive2, int, NULL, 0);
module_param_array(drive3, int, NULL, 0);

#include "paride.h"

#define PG_SPIN_DEL     50	/* spin delay in micro-seconds  */
#define PG_SPIN         200
#define PG_TMO		HZ
#define PG_RESET_TMO	10*HZ

#define STAT_ERR        0x01
#define STAT_INDEX      0x02
#define STAT_ECC        0x04
#define STAT_DRQ        0x08
#define STAT_SEEK       0x10
#define STAT_WRERR      0x20
#define STAT_READY      0x40
#define STAT_BUSY       0x80

#define ATAPI_IDENTIFY		0x12

static DEFINE_MUTEX(pg_mutex);
static int pg_open(struct inode *inode, struct file *file);
static int pg_release(struct inode *inode, struct file *file);
static ssize_t pg_read(struct file *filp, char __user *buf,
		       size_t count, loff_t * ppos);
static ssize_t pg_write(struct file *filp, const char __user *buf,
			size_t count, loff_t * ppos);
static int pg_detect(void);

#define PG_NAMELEN      8

struct pg {
	struct pi_adapter pia;	/* interface to paride layer */
	struct pi_adapter *pi;
	int busy;		/* write done, read expected */
	int start;		/* jiffies at command start */
	int dlen;		/* transfer size requested */
	unsigned long timeout;	/* timeout requested */
	int status;		/* last sense key */
	int drive;		/* drive */
	unsigned long access;	/* count of active opens ... */
	int present;		/* device present ? */
	char *bufptr;
	char name[PG_NAMELEN];	/* pg0, pg1, ... */
};

static struct pg devices[PG_UNITS];

static int pg_identify(struct pg *dev, int log);

static char pg_scratch[512];	/* scratch block buffer */

static struct class *pg_class;

/* kernel glue structures */

static const struct file_operations pg_fops = {
	.owner = THIS_MODULE,
	.read = pg_read,
	.write = pg_write,
	.open = pg_open,
	.release = pg_release,
	.llseek = noop_llseek,
};

static void pg_init_units(void)
{
	int unit;

	pg_drive_count = 0;
	for (unit = 0; unit < PG_UNITS; unit++) {
		int *parm = *drives[unit];
		struct pg *dev = &devices[unit];
		dev->pi = &dev->pia;
		clear_bit(0, &dev->access);
		dev->busy = 0;
		dev->present = 0;
		dev->bufptr = NULL;
		dev->drive = parm[D_SLV];
		snprintf(dev->name, PG_NAMELEN, "%s%c", name, 'a'+unit);
		if (parm[D_PRT])
			pg_drive_count++;
	}
}

static inline int status_reg(struct pg *dev)
{
	return pi_read_regr(dev->pi, 1, 6);
}

static inline int read_reg(struct pg *dev, int reg)
{
	return pi_read_regr(dev->pi, 0, reg);
}

static inline void write_reg(struct pg *dev, int reg, int val)
{
	pi_write_regr(dev->pi, 0, reg, val);
}

static inline u8 DRIVE(struct pg *dev)
{
	return 0xa0+0x10*dev->drive;
}

static void pg_sleep(int cs)
{
	schedule_timeout_interruptible(cs);
}

static int pg_wait(struct pg *dev, int go, int stop, unsigned long tmo, char *msg)
{
	int j, r, e, s, p, to;

	dev->status = 0;

	j = 0;
	while ((((r = status_reg(dev)) & go) || (stop && (!(r & stop))))
	       && time_before(jiffies, tmo)) {
		if (j++ < PG_SPIN)
			udelay(PG_SPIN_DEL);
		else
			pg_sleep(1);
	}

	to = time_after_eq(jiffies, tmo);

	if ((r & (STAT_ERR & stop)) || to) {
		s = read_reg(dev, 7);
		e = read_reg(dev, 1);
		p = read_reg(dev, 2);
		if (verbose > 1)
			printk("%s: %s: stat=0x%x err=0x%x phase=%d%s\n",
			       dev->name, msg, s, e, p, to ? " timeout" : "");
		if (to)
			e |= 0x100;
		dev->status = (e >> 4) & 0xff;
		return -1;
	}
	return 0;
}

static int pg_command(struct pg *dev, char *cmd, int dlen, unsigned long tmo)
{
	int k;

	pi_connect(dev->pi);

	write_reg(dev, 6, DRIVE(dev));

	if (pg_wait(dev, STAT_BUSY | STAT_DRQ, 0, tmo, "before command"))
		goto fail;

	write_reg(dev, 4, dlen % 256);
	write_reg(dev, 5, dlen / 256);
	write_reg(dev, 7, 0xa0);	/* ATAPI packet command */

	if (pg_wait(dev, STAT_BUSY, STAT_DRQ, tmo, "command DRQ"))
		goto fail;

	if (read_reg(dev, 2) != 1) {
		printk("%s: command phase error\n", dev->name);
		goto fail;
	}

	pi_write_block(dev->pi, cmd, 12);

	if (verbose > 1) {
		printk("%s: Command sent, dlen=%d packet= ", dev->name, dlen);
		for (k = 0; k < 12; k++)
			printk("%02x ", cmd[k] & 0xff);
		printk("\n");
	}
	return 0;
fail:
	pi_disconnect(dev->pi);
	return -1;
}

static int pg_completion(struct pg *dev, char *buf, unsigned long tmo)
{
	int r, d, n, p;

	r = pg_wait(dev, STAT_BUSY, STAT_DRQ | STAT_READY | STAT_ERR,
		    tmo, "completion");

	dev->dlen = 0;

	while (read_reg(dev, 7) & STAT_DRQ) {
		d = (read_reg(dev, 4) + 256 * read_reg(dev, 5));
		n = ((d + 3) & 0xfffc);
		p = read_reg(dev, 2) & 3;
		if (p == 0)
			pi_write_block(dev->pi, buf, n);
		if (p == 2)
			pi_read_block(dev->pi, buf, n);
		if (verbose > 1)
			printk("%s: %s %d bytes\n", dev->name,
			       p ? "Read" : "Write", n);
		dev->dlen += (1 - p) * d;
		buf += d;
		r = pg_wait(dev, STAT_BUSY, STAT_DRQ | STAT_READY | STAT_ERR,
			    tmo, "completion");
	}

	pi_disconnect(dev->pi);

	return r;
}

static int pg_reset(struct pg *dev)
{
	int i, k, err;
	int expect[5] = { 1, 1, 1, 0x14, 0xeb };
	int got[5];

	pi_connect(dev->pi);
	write_reg(dev, 6, DRIVE(dev));
	write_reg(dev, 7, 8);

	pg_sleep(20 * HZ / 1000);

	k = 0;
	while ((k++ < PG_RESET_TMO) && (status_reg(dev) & STAT_BUSY))
		pg_sleep(1);

	for (i = 0; i < 5; i++)
		got[i] = read_reg(dev, i + 1);

	err = memcmp(expect, got, sizeof(got)) ? -1 : 0;

	if (verbose) {
		printk("%s: Reset (%d) signature = ", dev->name, k);
		for (i = 0; i < 5; i++)
			printk("%3x", got[i]);
		if (err)
			printk(" (incorrect)");
		printk("\n");
	}

	pi_disconnect(dev->pi);
	return err;
}

static void xs(char *buf, char *targ, int len)
{
	char l = '\0';
	int k;

	for (k = 0; k < len; k++) {
		char c = *buf++;
		if (c != ' ' && c != l)
			l = *targ++ = c;
	}
	if (l == ' ')
		targ--;
	*targ = '\0';
}

static int pg_identify(struct pg *dev, int log)
{
	int s;
	char *ms[2] = { "master", "slave" };
	char mf[10], id[18];
	char id_cmd[12] = { ATAPI_IDENTIFY, 0, 0, 0, 36, 0, 0, 0, 0, 0, 0, 0 };
	char buf[36];

	s = pg_command(dev, id_cmd, 36, jiffies + PG_TMO);
	if (s)
		return -1;
	s = pg_completion(dev, buf, jiffies + PG_TMO);
	if (s)
		return -1;

	if (log) {
		xs(buf + 8, mf, 8);
		xs(buf + 16, id, 16);
		printk("%s: %s %s, %s\n", dev->name, mf, id, ms[dev->drive]);
	}

	return 0;
}

/*
 * returns  0, with id set if drive is detected
 *	   -1, if drive detection failed
 */
static int pg_probe(struct pg *dev)
{
	if (dev->drive == -1) {
		for (dev->drive = 0; dev->drive <= 1; dev->drive++)
			if (!pg_reset(dev))
				return pg_identify(dev, 1);
	} else {
		if (!pg_reset(dev))
			return pg_identify(dev, 1);
	}
	return -1;
}

static int pg_detect(void)
{
	struct pg *dev = &devices[0];
	int k, unit;

	printk("%s: %s version %s, major %d\n", name, name, PG_VERSION, major);

	k = 0;
	if (pg_drive_count == 0) {
		if (pi_init(dev->pi, 1, -1, -1, -1, -1, -1, pg_scratch,
			    PI_PG, verbose, dev->name)) {
			if (!pg_probe(dev)) {
				dev->present = 1;
				k++;
			} else
				pi_release(dev->pi);
		}

	} else
		for (unit = 0; unit < PG_UNITS; unit++, dev++) {
			int *parm = *drives[unit];
			if (!parm[D_PRT])
				continue;
			if (pi_init(dev->pi, 0, parm[D_PRT], parm[D_MOD],
				    parm[D_UNI], parm[D_PRO], parm[D_DLY],
				    pg_scratch, PI_PG, verbose, dev->name)) {
				if (!pg_probe(dev)) {
					dev->present = 1;
					k++;
				} else
					pi_release(dev->pi);
			}
		}

	if (k)
		return 0;

	printk("%s: No ATAPI device detected\n", name);
	return -1;
}

static int pg_open(struct inode *inode, struct file *file)
{
	int unit = iminor(inode) & 0x7f;
	struct pg *dev = &devices[unit];
	int ret = 0;

	mutex_lock(&pg_mutex);
	if ((unit >= PG_UNITS) || (!dev->present)) {
		ret = -ENODEV;
		goto out;
	}

	if (test_and_set_bit(0, &dev->access)) {
		ret = -EBUSY;
		goto out;
	}

	if (dev->busy) {
		pg_reset(dev);
		dev->busy = 0;
	}

	pg_identify(dev, (verbose > 1));

	dev->bufptr = kmalloc(PG_MAX_DATA, GFP_KERNEL);
	if (dev->bufptr == NULL) {
		clear_bit(0, &dev->access);
		printk("%s: buffer allocation failed\n", dev->name);
		ret = -ENOMEM;
		goto out;
	}

	file->private_data = dev;

out:
	mutex_unlock(&pg_mutex);
	return ret;
}

static int pg_release(struct inode *inode, struct file *file)
{
	struct pg *dev = file->private_data;

	kfree(dev->bufptr);
	dev->bufptr = NULL;
	clear_bit(0, &dev->access);

	return 0;
}

static ssize_t pg_write(struct file *filp, const char __user *buf, size_t count, loff_t *ppos)
{
	struct pg *dev = filp->private_data;
	struct pg_write_hdr hdr;
	int hs = sizeof (hdr);

	if (dev->busy)
		return -EBUSY;
	if (count < hs)
		return -EINVAL;

	if (copy_from_user(&hdr, buf, hs))
		return -EFAULT;

	if (hdr.magic != PG_MAGIC)
		return -EINVAL;
	if (hdr.dlen > PG_MAX_DATA)
		return -EINVAL;
	if ((count - hs) > PG_MAX_DATA)
		return -EINVAL;

	if (hdr.func == PG_RESET) {
		if (count != hs)
			return -EINVAL;
		if (pg_reset(dev))
			return -EIO;
		return count;
	}

	if (hdr.func != PG_COMMAND)
		return -EINVAL;

	dev->start = jiffies;
	dev->timeout = hdr.timeout * HZ + HZ / 2 + jiffies;

	if (pg_command(dev, hdr.packet, hdr.dlen, jiffies + PG_TMO)) {
		if (dev->status & 0x10)
			return -ETIME;
		return -EIO;
	}

	dev->busy = 1;

	if (copy_from_user(dev->bufptr, buf + hs, count - hs))
		return -EFAULT;
	return count;
}

static ssize_t pg_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
{
	struct pg *dev = filp->private_data;
	struct pg_read_hdr hdr;
	int hs = sizeof (hdr);
	int copy;

	if (!dev->busy)
		return -EINVAL;
	if (count < hs)
		return -EINVAL;

	dev->busy = 0;

	if (pg_completion(dev, dev->bufptr, dev->timeout))
		if (dev->status & 0x10)
			return -ETIME;

	hdr.magic = PG_MAGIC;
	hdr.dlen = dev->dlen;
	copy = 0;

	if (hdr.dlen < 0) {
		hdr.dlen = -1 * hdr.dlen;
		copy = hdr.dlen;
		if (copy > (count - hs))
			copy = count - hs;
	}

	hdr.duration = (jiffies - dev->start + HZ / 2) / HZ;
	hdr.scsi = dev->status & 0x0f;

	if (copy_to_user(buf, &hdr, hs))
		return -EFAULT;
	if (copy > 0)
		if (copy_to_user(buf + hs, dev->bufptr, copy))
			return -EFAULT;
	return copy + hs;
}

static int __init pg_init(void)
{
	int unit;
	int err;

	if (disable){
		err = -EINVAL;
		goto out;
	}

	pg_init_units();

	if (pg_detect()) {
		err = -ENODEV;
		goto out;
	}

	err = register_chrdev(major, name, &pg_fops);
	if (err < 0) {
		printk("pg_init: unable to get major number %d\n", major);
		for (unit = 0; unit < PG_UNITS; unit++) {
			struct pg *dev = &devices[unit];
			if (dev->present)
				pi_release(dev->pi);
		}
		goto out;
	}
	major = err;	/* In case the user specified `major=0' (dynamic) */
	pg_class = class_create(THIS_MODULE, "pg");
	if (IS_ERR(pg_class)) {
		err = PTR_ERR(pg_class);
		goto out_chrdev;
	}
	for (unit = 0; unit < PG_UNITS; unit++) {
		struct pg *dev = &devices[unit];
		if (dev->present)
			device_create(pg_class, NULL, MKDEV(major, unit), NULL,
				      "pg%u", unit);
	}
	err = 0;
	goto out;

out_chrdev:
	unregister_chrdev(major, "pg");
out:
	return err;
}

static void __exit pg_exit(void)
{
	int unit;

	for (unit = 0; unit < PG_UNITS; unit++) {
		struct pg *dev = &devices[unit];
		if (dev->present)
			device_destroy(pg_class, MKDEV(major, unit));
	}
	class_destroy(pg_class);
	unregister_chrdev(major, name);

	for (unit = 0; unit < PG_UNITS; unit++) {
		struct pg *dev = &devices[unit];
		if (dev->present)
			pi_release(dev->pi);
	}
}

MODULE_LICENSE("GPL");
module_init(pg_init)
module_exit(pg_exit)