aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/s390/char/tape_char.c
blob: 31566c55adfe18b7140c127bc87284a5a4353053 (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
/*
 *  drivers/s390/char/tape_char.c
 *    character device frontend for tape device driver
 *
 *  S390 and zSeries version
 *    Copyright IBM Corp. 2001,2006
 *    Author(s): Carsten Otte <cotte@de.ibm.com>
 *		 Michael Holzheu <holzheu@de.ibm.com>
 *		 Tuan Ngo-Anh <ngoanh@de.ibm.com>
 *		 Martin Schwidefsky <schwidefsky@de.ibm.com>
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/proc_fs.h>
#include <linux/mtio.h>
#include <linux/smp_lock.h>

#include <asm/uaccess.h>

#define TAPE_DBF_AREA	tape_core_dbf

#include "tape.h"
#include "tape_std.h"
#include "tape_class.h"

#define TAPECHAR_MAJOR		0	/* get dynamic major */

/*
 * file operation structure for tape character frontend
 */
static ssize_t tapechar_read(struct file *, char __user *, size_t, loff_t *);
static ssize_t tapechar_write(struct file *, const char __user *, size_t, loff_t *);
static int tapechar_open(struct inode *,struct file *);
static int tapechar_release(struct inode *,struct file *);
static int tapechar_ioctl(struct inode *, struct file *, unsigned int,
			  unsigned long);
static long tapechar_compat_ioctl(struct file *, unsigned int,
			  unsigned long);

static const struct file_operations tape_fops =
{
	.owner = THIS_MODULE,
	.read = tapechar_read,
	.write = tapechar_write,
	.ioctl = tapechar_ioctl,
	.compat_ioctl = tapechar_compat_ioctl,
	.open = tapechar_open,
	.release = tapechar_release,
};

static int tapechar_major = TAPECHAR_MAJOR;

/*
 * This function is called for every new tapedevice
 */
int
tapechar_setup_device(struct tape_device * device)
{
	char	device_name[20];

	sprintf(device_name, "ntibm%i", device->first_minor / 2);
	device->nt = register_tape_dev(
		&device->cdev->dev,
		MKDEV(tapechar_major, device->first_minor),
		&tape_fops,
		device_name,
		"non-rewinding"
	);
	device_name[0] = 'r';
	device->rt = register_tape_dev(
		&device->cdev->dev,
		MKDEV(tapechar_major, device->first_minor + 1),
		&tape_fops,
		device_name,
		"rewinding"
	);

	return 0;
}

void
tapechar_cleanup_device(struct tape_device *device)
{
	unregister_tape_dev(&device->cdev->dev, device->rt);
	device->rt = NULL;
	unregister_tape_dev(&device->cdev->dev, device->nt);
	device->nt = NULL;
}

static int
tapechar_check_idalbuffer(struct tape_device *device, size_t block_size)
{
	struct idal_buffer *new;

	if (device->char_data.idal_buf != NULL &&
	    device->char_data.idal_buf->size == block_size)
		return 0;

	if (block_size > MAX_BLOCKSIZE) {
		DBF_EVENT(3, "Invalid blocksize (%zd > %d)\n",
			block_size, MAX_BLOCKSIZE);
		return -EINVAL;
	}

	/* The current idal buffer is not correct. Allocate a new one. */
	new = idal_buffer_alloc(block_size, 0);
	if (IS_ERR(new))
		return -ENOMEM;

	if (device->char_data.idal_buf != NULL)
		idal_buffer_free(device->char_data.idal_buf);

	device->char_data.idal_buf = new;

	return 0;
}

/*
 * Tape device read function
 */
static ssize_t
tapechar_read(struct file *filp, char __user *data, size_t count, loff_t *ppos)
{
	struct tape_device *device;
	struct tape_request *request;
	size_t block_size;
	int rc;

	DBF_EVENT(6, "TCHAR:read\n");
	device = (struct tape_device *) filp->private_data;

	/*
	 * If the tape isn't terminated yet, do it now. And since we then
	 * are at the end of the tape there wouldn't be anything to read
	 * anyways. So we return immediatly.
	 */
	if(device->required_tapemarks) {
		return tape_std_terminate_write(device);
	}

	/* Find out block size to use */
	if (device->char_data.block_size != 0) {
		if (count < device->char_data.block_size) {
			DBF_EVENT(3, "TCHAR:read smaller than block "
				  "size was requested\n");
			return -EINVAL;
		}
		block_size = device->char_data.block_size;
	} else {
		block_size = count;
	}

	rc = tapechar_check_idalbuffer(device, block_size);
	if (rc)
		return rc;

#ifdef CONFIG_S390_TAPE_BLOCK
	/* Changes position. */
	device->blk_data.medium_changed = 1;
#endif

	DBF_EVENT(6, "TCHAR:nbytes: %lx\n", block_size);
	/* Let the discipline build the ccw chain. */
	request = device->discipline->read_block(device, block_size);
	if (IS_ERR(request))
		return PTR_ERR(request);
	/* Execute it. */
	rc = tape_do_io(device, request);
	if (rc == 0) {
		rc = block_size - request->rescnt;
		DBF_EVENT(6, "TCHAR:rbytes:  %x\n", rc);
		filp->f_pos += rc;
		/* Copy data from idal buffer to user space. */
		if (idal_buffer_to_user(device->char_data.idal_buf,
					data, rc) != 0)
			rc = -EFAULT;
	}
	tape_free_request(request);
	return rc;
}

/*
 * Tape device write function
 */
static ssize_t
tapechar_write(struct file *filp, const char __user *data, size_t count, loff_t *ppos)
{
	struct tape_device *device;
	struct tape_request *request;
	size_t block_size;
	size_t written;
	int nblocks;
	int i, rc;

	DBF_EVENT(6, "TCHAR:write\n");
	device = (struct tape_device *) filp->private_data;
	/* Find out block size and number of blocks */
	if (device->char_data.block_size != 0) {
		if (count < device->char_data.block_size) {
			DBF_EVENT(3, "TCHAR:write smaller than block "
				  "size was requested\n");
			return -EINVAL;
		}
		block_size = device->char_data.block_size;
		nblocks = count / block_size;
	} else {
		block_size = count;
		nblocks = 1;
	}

	rc = tapechar_check_idalbuffer(device, block_size);
	if (rc)
		return rc;

#ifdef CONFIG_S390_TAPE_BLOCK
	/* Changes position. */
	device->blk_data.medium_changed = 1;
#endif

	DBF_EVENT(6,"TCHAR:nbytes: %lx\n", block_size);
	DBF_EVENT(6, "TCHAR:nblocks: %x\n", nblocks);
	/* Let the discipline build the ccw chain. */
	request = device->discipline->write_block(device, block_size);
	if (IS_ERR(request))
		return PTR_ERR(request);
	rc = 0;
	written = 0;
	for (i = 0; i < nblocks; i++) {
		/* Copy data from user space to idal buffer. */
		if (idal_buffer_from_user(device->char_data.idal_buf,
					  data, block_size)) {
			rc = -EFAULT;
			break;
		}
		rc = tape_do_io(device, request);
		if (rc)
			break;
		DBF_EVENT(6, "TCHAR:wbytes: %lx\n",
			  block_size - request->rescnt);
		filp->f_pos += block_size - request->rescnt;
		written += block_size - request->rescnt;
		if (request->rescnt != 0)
			break;
		data += block_size;
	}
	tape_free_request(request);
	if (rc == -ENOSPC) {
		/*
		 * Ok, the device has no more space. It has NOT written
		 * the block.
		 */
		if (device->discipline->process_eov)
			device->discipline->process_eov(device);
		if (written > 0)
			rc = 0;

	}

	/*
	 * After doing a write we always need two tapemarks to correctly
	 * terminate the tape (one to terminate the file, the second to
	 * flag the end of recorded data.
	 * Since process_eov positions the tape in front of the written
	 * tapemark it doesn't hurt to write two marks again.
	 */
	if (!rc)
		device->required_tapemarks = 2;

	return rc ? rc : written;
}

/*
 * Character frontend tape device open function.
 */
static int
tapechar_open (struct inode *inode, struct file *filp)
{
	struct tape_device *device;
	int minor, rc;

	DBF_EVENT(6, "TCHAR:open: %i:%i\n",
		imajor(filp->f_path.dentry->d_inode),
		iminor(filp->f_path.dentry->d_inode));

	if (imajor(filp->f_path.dentry->d_inode) != tapechar_major)
		return -ENODEV;

	lock_kernel();
	minor = iminor(filp->f_path.dentry->d_inode);
	device = tape_get_device(minor / TAPE_MINORS_PER_DEV);
	if (IS_ERR(device)) {
		DBF_EVENT(3, "TCHAR:open: tape_get_device() failed\n");
		rc = PTR_ERR(device);
		goto out;
	}


	rc = tape_open(device);
	if (rc == 0) {
		filp->private_data = device;
		rc = nonseekable_open(inode, filp);
	}
	else
		tape_put_device(device);

out:
	unlock_kernel();
	return rc;
}

/*
 * Character frontend tape device release function.
 */

static int
tapechar_release(struct inode *inode, struct file *filp)
{
	struct tape_device *device;

	DBF_EVENT(6, "TCHAR:release: %x\n", iminor(inode));
	device = (struct tape_device *) filp->private_data;

	/*
	 * If this is the rewinding tape minor then rewind. In that case we
	 * write all required tapemarks. Otherwise only one to terminate the
	 * file.
	 */
	if ((iminor(inode) & 1) != 0) {
		if (device->required_tapemarks)
			tape_std_terminate_write(device);
		tape_mtop(device, MTREW, 1);
	} else {
		if (device->required_tapemarks > 1) {
			if (tape_mtop(device, MTWEOF, 1) == 0)
				device->required_tapemarks--;
		}
	}

	if (device->char_data.idal_buf != NULL) {
		idal_buffer_free(device->char_data.idal_buf);
		device->char_data.idal_buf = NULL;
	}
	tape_release(device);
	filp->private_data = tape_put_device(device);

	return 0;
}

/*
 * Tape device io controls.
 */
static int
tapechar_ioctl(struct inode *inp, struct file *filp,
	       unsigned int no, unsigned long data)
{
	struct tape_device *device;
	int rc;

	DBF_EVENT(6, "TCHAR:ioct\n");

	device = (struct tape_device *) filp->private_data;

	if (no == MTIOCTOP) {
		struct mtop op;

		if (copy_from_user(&op, (char __user *) data, sizeof(op)) != 0)
			return -EFAULT;
		if (op.mt_count < 0)
			return -EINVAL;

		/*
		 * Operations that change tape position should write final
		 * tapemarks.
		 */
		switch (op.mt_op) {
			case MTFSF:
			case MTBSF:
			case MTFSR:
			case MTBSR:
			case MTREW:
			case MTOFFL:
			case MTEOM:
			case MTRETEN:
			case MTBSFM:
			case MTFSFM:
			case MTSEEK:
#ifdef CONFIG_S390_TAPE_BLOCK
				device->blk_data.medium_changed = 1;
#endif
				if (device->required_tapemarks)
					tape_std_terminate_write(device);
			default:
				;
		}
		rc = tape_mtop(device, op.mt_op, op.mt_count);

		if (op.mt_op == MTWEOF && rc == 0) {
			if (op.mt_count > device->required_tapemarks)
				device->required_tapemarks = 0;
			else
				device->required_tapemarks -= op.mt_count;
		}
		return rc;
	}
	if (no == MTIOCPOS) {
		/* MTIOCPOS: query the tape position. */
		struct mtpos pos;

		rc = tape_mtop(device, MTTELL, 1);
		if (rc < 0)
			return rc;
		pos.mt_blkno = rc;
		if (copy_to_user((char __user *) data, &pos, sizeof(pos)) != 0)
			return -EFAULT;
		return 0;
	}
	if (no == MTIOCGET) {
		/* MTIOCGET: query the tape drive status. */
		struct mtget get;

		memset(&get, 0, sizeof(get));
		get.mt_type = MT_ISUNKNOWN;
		get.mt_resid = 0 /* device->devstat.rescnt */;
		get.mt_dsreg = device->tape_state;
		/* FIXME: mt_gstat, mt_erreg, mt_fileno */
		get.mt_gstat = 0;
		get.mt_erreg = 0;
		get.mt_fileno = 0;
		get.mt_gstat  = device->tape_generic_status;

		if (device->medium_state == MS_LOADED) {
			rc = tape_mtop(device, MTTELL, 1);

			if (rc < 0)
				return rc;

			if (rc == 0)
				get.mt_gstat |= GMT_BOT(~0);

			get.mt_blkno = rc;
		}

		if (copy_to_user((char __user *) data, &get, sizeof(get)) != 0)
			return -EFAULT;

		return 0;
	}
	/* Try the discipline ioctl function. */
	if (device->discipline->ioctl_fn == NULL)
		return -EINVAL;
	return device->discipline->ioctl_fn(device, no, data);
}

static long
tapechar_compat_ioctl(struct file *filp, unsigned int no, unsigned long data)
{
	struct tape_device *device = filp->private_data;
	int rval = -ENOIOCTLCMD;

	if (device->discipline->ioctl_fn) {
		lock_kernel();
		rval = device->discipline->ioctl_fn(device, no, data);
		unlock_kernel();
		if (rval == -EINVAL)
			rval = -ENOIOCTLCMD;
	}

	return rval;
}

/*
 * Initialize character device frontend.
 */
int
tapechar_init (void)
{
	dev_t	dev;

	if (alloc_chrdev_region(&dev, 0, 256, "tape") != 0)
		return -1;

	tapechar_major = MAJOR(dev);

	return 0;
}

/*
 * cleanup
 */
void
tapechar_exit(void)
{
	unregister_chrdev_region(MKDEV(tapechar_major, 0), 256);
}