summaryrefslogtreecommitdiffstats
path: root/drivers/usb/class/usbtmc.c
blob: b09a527f73411499e2ab712c0f4d1b6f7d2c1946 (plain)
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
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
/**
 * drivers/usb/class/usbtmc.c - USB Test & Measurment class driver
 *
 * Copyright (C) 2007 Stefan Kopp, Gechingen, Germany
 * Copyright (C) 2008 Novell, Inc.
 * Copyright (C) 2008 Greg Kroah-Hartman <gregkh@suse.de>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * The GNU General Public License is available at
 * http://www.gnu.org/copyleft/gpl.html.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/kref.h>
#include <linux/mutex.h>
#include <linux/usb.h>
#include <linux/usb/tmc.h>


#define USBTMC_MINOR_BASE	176

/*
 * Size of driver internal IO buffer. Must be multiple of 4 and at least as
 * large as wMaxPacketSize (which is usually 512 bytes).
 */
#define USBTMC_SIZE_IOBUFFER	2048

/* Default USB timeout (in milliseconds) */
#define USBTMC_TIMEOUT		10

/*
 * Maximum number of read cycles to empty bulk in endpoint during CLEAR and
 * ABORT_BULK_IN requests. Ends the loop if (for whatever reason) a short
 * packet is never read.
 */
#define USBTMC_MAX_READS_TO_CLEAR_BULK_IN	100

static struct usb_device_id usbtmc_devices[] = {
	{ USB_INTERFACE_INFO(USB_CLASS_APP_SPEC, 3, 0), },
	{ USB_INTERFACE_INFO(USB_CLASS_APP_SPEC, 3, 1), },
	{ 0, } /* terminating entry */
};
MODULE_DEVICE_TABLE(usb, usbtmc_devices);

/*
 * This structure is the capabilities for the device
 * See section 4.2.1.8 of the USBTMC specification for details.
 */
struct usbtmc_dev_capabilities {
	__u8 interface_capabilities;
	__u8 device_capabilities;
	__u8 usb488_interface_capabilities;
	__u8 usb488_device_capabilities;
};

/* This structure holds private data for each USBTMC device. One copy is
 * allocated for each USBTMC device in the driver's probe function.
 */
struct usbtmc_device_data {
	const struct usb_device_id *id;
	struct usb_device *usb_dev;
	struct usb_interface *intf;

	unsigned int bulk_in;
	unsigned int bulk_out;

	u8 bTag;
	u8 bTag_last_write;	/* needed for abort */
	u8 bTag_last_read;	/* needed for abort */

	/* attributes from the USB TMC spec for this device */
	u8 TermChar;
	bool TermCharEnabled;
	bool auto_abort;

	struct usbtmc_dev_capabilities	capabilities;
	struct kref kref;
	struct mutex io_mutex;	/* only one i/o function running at a time */
};
#define to_usbtmc_data(d) container_of(d, struct usbtmc_device_data, kref)

/* Forward declarations */
static struct usb_driver usbtmc_driver;

static void usbtmc_delete(struct kref *kref)
{
	struct usbtmc_device_data *data = to_usbtmc_data(kref);

	usb_put_dev(data->usb_dev);
	kfree(data);
}

static int usbtmc_open(struct inode *inode, struct file *filp)
{
	struct usb_interface *intf;
	struct usbtmc_device_data *data;
	int retval = 0;

	intf = usb_find_interface(&usbtmc_driver, iminor(inode));
	if (!intf) {
		printk(KERN_ERR KBUILD_MODNAME
		       ": can not find device for minor %d", iminor(inode));
		retval = -ENODEV;
		goto exit;
	}

	data = usb_get_intfdata(intf);
	kref_get(&data->kref);

	/* Store pointer in file structure's private data field */
	filp->private_data = data;

exit:
	return retval;
}

static int usbtmc_release(struct inode *inode, struct file *file)
{
	struct usbtmc_device_data *data = file->private_data;

	kref_put(&data->kref, usbtmc_delete);
	return 0;
}

static int usbtmc_ioctl_abort_bulk_in(struct usbtmc_device_data *data)
{
	u8 *buffer;
	struct device *dev;
	int rv;
	int n;
	int actual;
	struct usb_host_interface *current_setting;
	int max_size;

	dev = &data->intf->dev;
	buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
	if (!buffer)
		return -ENOMEM;

	rv = usb_control_msg(data->usb_dev,
			     usb_rcvctrlpipe(data->usb_dev, 0),
			     USBTMC_REQUEST_INITIATE_ABORT_BULK_IN,
			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
			     data->bTag_last_read, data->bulk_in,
			     buffer, 2, USBTMC_TIMEOUT);

	if (rv < 0) {
		dev_err(dev, "usb_control_msg returned %d\n", rv);
		goto exit;
	}

	dev_dbg(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);

	if (buffer[0] == USBTMC_STATUS_FAILED) {
		rv = 0;
		goto exit;
	}

	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
		dev_err(dev, "INITIATE_ABORT_BULK_IN returned %x\n",
			buffer[0]);
		rv = -EPERM;
		goto exit;
	}

	max_size = 0;
	current_setting = data->intf->cur_altsetting;
	for (n = 0; n < current_setting->desc.bNumEndpoints; n++)
		if (current_setting->endpoint[n].desc.bEndpointAddress ==
			data->bulk_in)
			max_size = le16_to_cpu(current_setting->endpoint[n].
						desc.wMaxPacketSize);

	if (max_size == 0) {
		dev_err(dev, "Couldn't get wMaxPacketSize\n");
		rv = -EPERM;
		goto exit;
	}

	dev_dbg(&data->intf->dev, "wMaxPacketSize is %d\n", max_size);

	n = 0;

	do {
		dev_dbg(dev, "Reading from bulk in EP\n");

		rv = usb_bulk_msg(data->usb_dev,
				  usb_rcvbulkpipe(data->usb_dev,
						  data->bulk_in),
				  buffer, USBTMC_SIZE_IOBUFFER,
				  &actual, USBTMC_TIMEOUT);

		n++;

		if (rv < 0) {
			dev_err(dev, "usb_bulk_msg returned %d\n", rv);
			goto exit;
		}
	} while ((actual == max_size) &&
		 (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));

	if (actual == max_size) {
		dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
			USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
		rv = -EPERM;
		goto exit;
	}

	n = 0;

usbtmc_abort_bulk_in_status:
	rv = usb_control_msg(data->usb_dev,
			     usb_rcvctrlpipe(data->usb_dev, 0),
			     USBTMC_REQUEST_CHECK_ABORT_BULK_IN_STATUS,
			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
			     0, data->bulk_in, buffer, 0x08,
			     USBTMC_TIMEOUT);

	if (rv < 0) {
		dev_err(dev, "usb_control_msg returned %d\n", rv);
		goto exit;
	}

	dev_dbg(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);

	if (buffer[0] == USBTMC_STATUS_SUCCESS) {
		rv = 0;
		goto exit;
	}

	if (buffer[0] != USBTMC_STATUS_PENDING) {
		dev_err(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
		rv = -EPERM;
		goto exit;
	}

	if (buffer[1] == 1)
		do {
			dev_dbg(dev, "Reading from bulk in EP\n");

			rv = usb_bulk_msg(data->usb_dev,
					  usb_rcvbulkpipe(data->usb_dev,
							  data->bulk_in),
					  buffer, USBTMC_SIZE_IOBUFFER,
					  &actual, USBTMC_TIMEOUT);

			n++;

			if (rv < 0) {
				dev_err(dev, "usb_bulk_msg returned %d\n", rv);
				goto exit;
			}
		} while ((actual = max_size) &&
			 (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));

	if (actual == max_size) {
		dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
			USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
		rv = -EPERM;
		goto exit;
	}

	goto usbtmc_abort_bulk_in_status;

exit:
	kfree(buffer);
	return rv;

}

static int usbtmc_ioctl_abort_bulk_out(struct usbtmc_device_data *data)
{
	struct device *dev;
	u8 *buffer;
	int rv;
	int n;

	dev = &data->intf->dev;

	buffer = kmalloc(8, GFP_KERNEL);
	if (!buffer)
		return -ENOMEM;

	rv = usb_control_msg(data->usb_dev,
			     usb_rcvctrlpipe(data->usb_dev, 0),
			     USBTMC_REQUEST_INITIATE_ABORT_BULK_OUT,
			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
			     data->bTag_last_write, data->bulk_out,
			     buffer, 2, USBTMC_TIMEOUT);

	if (rv < 0) {
		dev_err(dev, "usb_control_msg returned %d\n", rv);
		goto exit;
	}

	dev_dbg(dev, "INITIATE_ABORT_BULK_OUT returned %x\n", buffer[0]);

	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
		dev_err(dev, "INITIATE_ABORT_BULK_OUT returned %x\n",
			buffer[0]);
		rv = -EPERM;
		goto exit;
	}

	n = 0;

usbtmc_abort_bulk_out_check_status:
	rv = usb_control_msg(data->usb_dev,
			     usb_rcvctrlpipe(data->usb_dev, 0),
			     USBTMC_REQUEST_CHECK_ABORT_BULK_OUT_STATUS,
			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
			     0, data->bulk_out, buffer, 0x08,
			     USBTMC_TIMEOUT);
	n++;
	if (rv < 0) {
		dev_err(dev, "usb_control_msg returned %d\n", rv);
		goto exit;
	}

	dev_dbg(dev, "CHECK_ABORT_BULK_OUT returned %x\n", buffer[0]);

	if (buffer[0] == USBTMC_STATUS_SUCCESS)
		goto usbtmc_abort_bulk_out_clear_halt;

	if ((buffer[0] == USBTMC_STATUS_PENDING) &&
	    (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN))
		goto usbtmc_abort_bulk_out_check_status;

	rv = -EPERM;
	goto exit;

usbtmc_abort_bulk_out_clear_halt:
	rv = usb_control_msg(data->usb_dev,
			     usb_sndctrlpipe(data->usb_dev, 0),
			     USB_REQ_CLEAR_FEATURE,
			     USB_DIR_OUT | USB_TYPE_STANDARD |
			     USB_RECIP_ENDPOINT,
			     USB_ENDPOINT_HALT, data->bulk_out, buffer,
			     0, USBTMC_TIMEOUT);

	if (rv < 0) {
		dev_err(dev, "usb_control_msg returned %d\n", rv);
		goto exit;
	}
	rv = 0;

exit:
	kfree(buffer);
	return rv;
}

static ssize_t usbtmc_read(struct file *filp, char __user *buf,
			   size_t count, loff_t *f_pos)
{
	struct usbtmc_device_data *data;
	struct device *dev;
	unsigned long int n_characters;
	u8 *buffer;
	int actual;
	int done;
	int remaining;
	int retval;
	int this_part;

	/* Get pointer to private data structure */
	data = filp->private_data;
	dev = &data->intf->dev;

	buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
	if (!buffer)
		return -ENOMEM;

	mutex_lock(&data->io_mutex);

	remaining = count;
	done = 0;

	while (remaining > 0) {
		if (remaining > USBTMC_SIZE_IOBUFFER - 12 - 3)
			this_part = USBTMC_SIZE_IOBUFFER - 12 - 3;
		else
			this_part = remaining;

		/* Setup IO buffer for DEV_DEP_MSG_IN message
		 * Refer to class specs for details
		 */
		buffer[0] = 2;
		buffer[1] = data->bTag;
		buffer[2] = ~(data->bTag);
		buffer[3] = 0; /* Reserved */
		buffer[4] = (this_part - 12 - 3) & 255;
		buffer[5] = ((this_part - 12 - 3) >> 8) & 255;
		buffer[6] = ((this_part - 12 - 3) >> 16) & 255;
		buffer[7] = ((this_part - 12 - 3) >> 24) & 255;
		buffer[8] = data->TermCharEnabled * 2;
		/* Use term character? */
		buffer[9] = data->TermChar;
		buffer[10] = 0; /* Reserved */
		buffer[11] = 0; /* Reserved */

		/* Send bulk URB */
		retval = usb_bulk_msg(data->usb_dev,
				      usb_sndbulkpipe(data->usb_dev,
						      data->bulk_out),
				      buffer, 12, &actual, USBTMC_TIMEOUT);

		/* Store bTag (in case we need to abort) */
		data->bTag_last_write = data->bTag;

		/* Increment bTag -- and increment again if zero */
		data->bTag++;
		if (!data->bTag)
			(data->bTag)++;

		if (retval < 0) {
			dev_err(dev, "usb_bulk_msg returned %d\n", retval);
			if (data->auto_abort)
				usbtmc_ioctl_abort_bulk_out(data);
			goto exit;
		}

		/* Send bulk URB */
		retval = usb_bulk_msg(data->usb_dev,
				      usb_rcvbulkpipe(data->usb_dev,
						      data->bulk_in),
				      buffer, USBTMC_SIZE_IOBUFFER, &actual,
				      USBTMC_TIMEOUT);

		/* Store bTag (in case we need to abort) */
		data->bTag_last_read = data->bTag;

		if (retval < 0) {
			dev_err(dev, "Unable to read data, error %d\n", retval);
			if (data->auto_abort)
				usbtmc_ioctl_abort_bulk_in(data);
			goto exit;
		}

		/* How many characters did the instrument send? */
		n_characters = buffer[4] +
			       (buffer[5] << 8) +
			       (buffer[6] << 16) +
			       (buffer[7] << 24);

		/* Copy buffer to user space */
		if (copy_to_user(buf + done, &buffer[12], n_characters)) {
			/* There must have been an addressing problem */
			retval = -EFAULT;
			goto exit;
		}

		done += n_characters;
		if (n_characters < USBTMC_SIZE_IOBUFFER)
			remaining = 0;
	}

	/* Update file position value */
	*f_pos = *f_pos + done;
	retval = done;

exit:
	mutex_unlock(&data->io_mutex);
	kfree(buffer);
	return retval;
}

static ssize_t usbtmc_write(struct file *filp, const char __user *buf,
			    size_t count, loff_t *f_pos)
{
	struct usbtmc_device_data *data;
	u8 *buffer;
	int retval;
	int actual;
	unsigned long int n_bytes;
	int remaining;
	int done;
	int this_part;

	data = filp->private_data;

	buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
	if (!buffer)
		return -ENOMEM;

	mutex_lock(&data->io_mutex);

	remaining = count;
	done = 0;

	while (remaining > 0) {
		if (remaining > USBTMC_SIZE_IOBUFFER - 12) {
			this_part = USBTMC_SIZE_IOBUFFER - 12;
			buffer[8] = 0;
		} else {
			this_part = remaining;
			buffer[8] = 1;
		}

		/* Setup IO buffer for DEV_DEP_MSG_OUT message */
		buffer[0] = 1;
		buffer[1] = data->bTag;
		buffer[2] = ~(data->bTag);
		buffer[3] = 0; /* Reserved */
		buffer[4] = this_part & 255;
		buffer[5] = (this_part >> 8) & 255;
		buffer[6] = (this_part >> 16) & 255;
		buffer[7] = (this_part >> 24) & 255;
		/* buffer[8] is set above... */
		buffer[9] = 0; /* Reserved */
		buffer[10] = 0; /* Reserved */
		buffer[11] = 0; /* Reserved */

		if (copy_from_user(&buffer[12], buf + done, this_part)) {
			retval = -EFAULT;
			goto exit;
		}

		n_bytes = roundup(12 + this_part, 4);
		memset(buffer + 12 + this_part, 0, n_bytes - (12 + this_part));

		retval = usb_bulk_msg(data->usb_dev,
				      usb_sndbulkpipe(data->usb_dev,
						      data->bulk_out),
				      buffer, n_bytes, &actual, USBTMC_TIMEOUT);

		data->bTag_last_write = data->bTag;
		data->bTag++;

		if (!data->bTag)
			data->bTag++;

		if (retval < 0) {
			dev_err(&data->intf->dev,
				"Unable to send data, error %d\n", retval);
			if (data->auto_abort)
				usbtmc_ioctl_abort_bulk_out(data);
			goto exit;
		}

		remaining -= this_part;
		done += this_part;
	}

	retval = count;
exit:
	mutex_unlock(&data->io_mutex);
	kfree(buffer);
	return retval;
}

static int usbtmc_ioctl_clear(struct usbtmc_device_data *data)
{
	struct usb_host_interface *current_setting;
	struct usb_endpoint_descriptor *desc;
	struct device *dev;
	u8 *buffer;
	int rv;
	int n;
	int actual;
	int max_size;

	dev = &data->intf->dev;

	dev_dbg(dev, "Sending INITIATE_CLEAR request\n");

	buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
	if (!buffer)
		return -ENOMEM;

	rv = usb_control_msg(data->usb_dev,
			     usb_rcvctrlpipe(data->usb_dev, 0),
			     USBTMC_REQUEST_INITIATE_CLEAR,
			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
			     0, 0, buffer, 1, USBTMC_TIMEOUT);
	if (rv < 0) {
		dev_err(dev, "usb_control_msg returned %d\n", rv);
		goto exit;
	}

	dev_dbg(dev, "INITIATE_CLEAR returned %x\n", buffer[0]);

	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
		dev_err(dev, "INITIATE_CLEAR returned %x\n", buffer[0]);
		rv = -EPERM;
		goto exit;
	}

	max_size = 0;
	current_setting = data->intf->cur_altsetting;
	for (n = 0; n < current_setting->desc.bNumEndpoints; n++) {
		desc = &current_setting->endpoint[n].desc;
		if (desc->bEndpointAddress == data->bulk_in)
			max_size = le16_to_cpu(desc->wMaxPacketSize);
	}

	if (max_size == 0) {
		dev_err(dev, "Couldn't get wMaxPacketSize\n");
		rv = -EPERM;
		goto exit;
	}

	dev_dbg(dev, "wMaxPacketSize is %d\n", max_size);

	n = 0;

usbtmc_clear_check_status:

	dev_dbg(dev, "Sending CHECK_CLEAR_STATUS request\n");

	rv = usb_control_msg(data->usb_dev,
			     usb_rcvctrlpipe(data->usb_dev, 0),
			     USBTMC_REQUEST_CHECK_CLEAR_STATUS,
			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
			     0, 0, buffer, 2, USBTMC_TIMEOUT);
	if (rv < 0) {
		dev_err(dev, "usb_control_msg returned %d\n", rv);
		goto exit;
	}

	dev_dbg(dev, "CHECK_CLEAR_STATUS returned %x\n", buffer[0]);

	if (buffer[0] == USBTMC_STATUS_SUCCESS)
		goto usbtmc_clear_bulk_out_halt;

	if (buffer[0] != USBTMC_STATUS_PENDING) {
		dev_err(dev, "CHECK_CLEAR_STATUS returned %x\n", buffer[0]);
		rv = -EPERM;
		goto exit;
	}

	if (buffer[1] == 1)
		do {
			dev_dbg(dev, "Reading from bulk in EP\n");

			rv = usb_bulk_msg(data->usb_dev,
					  usb_rcvbulkpipe(data->usb_dev,
							  data->bulk_in),
					  buffer, USBTMC_SIZE_IOBUFFER,
					  &actual, USBTMC_TIMEOUT);
			n++;

			if (rv < 0) {
				dev_err(dev, "usb_control_msg returned %d\n",
					rv);
				goto exit;
			}
		} while ((actual == max_size) &&
			  (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));

	if (actual == max_size) {
		dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
			USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
		rv = -EPERM;
		goto exit;
	}

	goto usbtmc_clear_check_status;

usbtmc_clear_bulk_out_halt:

	rv = usb_control_msg(data->usb_dev,
			     usb_sndctrlpipe(data->usb_dev, 0),
			     USB_REQ_CLEAR_FEATURE,
			     USB_DIR_OUT | USB_TYPE_STANDARD |
			     USB_RECIP_ENDPOINT,
			     USB_ENDPOINT_HALT,
			     data->bulk_out, buffer, 0,
			     USBTMC_TIMEOUT);
	if (rv < 0) {
		dev_err(dev, "usb_control_msg returned %d\n", rv);
		goto exit;
	}
	rv = 0;

exit:
	kfree(buffer);
	return rv;
}

static int usbtmc_ioctl_clear_out_halt(struct usbtmc_device_data *data)
{
	u8 *buffer;
	int rv;

	buffer = kmalloc(2, GFP_KERNEL);
	if (!buffer)
		return -ENOMEM;

	rv = usb_control_msg(data->usb_dev,
			     usb_sndctrlpipe(data->usb_dev, 0),
			     USB_REQ_CLEAR_FEATURE,
			     USB_DIR_OUT | USB_TYPE_STANDARD |
			     USB_RECIP_ENDPOINT,
			     USB_ENDPOINT_HALT, data->bulk_out,
			     buffer, 0, USBTMC_TIMEOUT);

	if (rv < 0) {
		dev_err(&data->usb_dev->dev, "usb_control_msg returned %d\n",
			rv);
		goto exit;
	}
	rv = 0;

exit:
	kfree(buffer);
	return rv;
}

static int usbtmc_ioctl_clear_in_halt(struct usbtmc_device_data *data)
{
	u8 *buffer;
	int rv;

	buffer = kmalloc(2, GFP_KERNEL);
	if (!buffer)
		return -ENOMEM;

	rv = usb_control_msg(data->usb_dev, usb_sndctrlpipe(data->usb_dev, 0),
			     USB_REQ_CLEAR_FEATURE,
			     USB_DIR_OUT | USB_TYPE_STANDARD |
			     USB_RECIP_ENDPOINT,
			     USB_ENDPOINT_HALT, data->bulk_in, buffer, 0,
			     USBTMC_TIMEOUT);

	if (rv < 0) {
		dev_err(&data->usb_dev->dev, "usb_control_msg returned %d\n",
			rv);
		goto exit;
	}
	rv = 0;

exit:
	kfree(buffer);
	return rv;
}

static int get_capabilities(struct usbtmc_device_data *data)
{
	struct device *dev = &data->usb_dev->dev;
	char *buffer;
	int rv = 0;

	buffer = kmalloc(0x18, GFP_KERNEL);
	if (!buffer)
		return -ENOMEM;

	rv = usb_control_msg(data->usb_dev, usb_rcvctrlpipe(data->usb_dev, 0),
			     USBTMC_REQUEST_GET_CAPABILITIES,
			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
			     0, 0, buffer, 0x18, USBTMC_TIMEOUT);
	if (rv < 0) {
		dev_err(dev, "usb_control_msg returned %d\n", rv);
		goto err_out;
	}

	dev_dbg(dev, "GET_CAPABILITIES returned %x\n", buffer[0]);
	dev_dbg(dev, "Interface capabilities are %x\n", buffer[4]);
	dev_dbg(dev, "Device capabilities are %x\n", buffer[5]);
	dev_dbg(dev, "USB488 interface capabilities are %x\n", buffer[14]);
	dev_dbg(dev, "USB488 device capabilities are %x\n", buffer[15]);
	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
		dev_err(dev, "GET_CAPABILITIES returned %x\n", buffer[0]);
		rv = -EPERM;
		goto err_out;
	}

	data->capabilities.interface_capabilities = buffer[4];
	data->capabilities.device_capabilities = buffer[5];
	data->capabilities.usb488_interface_capabilities = buffer[14];
	data->capabilities.usb488_device_capabilities = buffer[15];

err_out:
	kfree(buffer);
	return rv;
}

#define capability_attribute(name)					\
static ssize_t show_##name(struct device *dev,				\
			   struct device_attribute *attr, char *buf)	\
{									\
	struct usb_interface *intf = to_usb_interface(dev);		\
	struct usbtmc_device_data *data = usb_get_intfdata(intf);	\
									\
	return sprintf(buf, "%d\n", data->capabilities.name);		\
}									\
static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)

capability_attribute(interface_capabilities);
capability_attribute(device_capabilities);
capability_attribute(usb488_interface_capabilities);
capability_attribute(usb488_device_capabilities);

static struct attribute *capability_attrs[] = {
	&dev_attr_interface_capabilities.attr,
	&dev_attr_device_capabilities.attr,
	&dev_attr_usb488_interface_capabilities.attr,
	&dev_attr_usb488_device_capabilities.attr,
	NULL,
};

static struct attribute_group capability_attr_grp = {
	.attrs = capability_attrs,
};

static ssize_t show_TermChar(struct device *dev,
			     struct device_attribute *attr, char *buf)
{
	struct usb_interface *intf = to_usb_interface(dev);
	struct usbtmc_device_data *data = usb_get_intfdata(intf);

	return sprintf(buf, "%c\n", data->TermChar);
}

static ssize_t store_TermChar(struct device *dev,
			      struct device_attribute *attr,
			      const char *buf, size_t count)
{
	struct usb_interface *intf = to_usb_interface(dev);
	struct usbtmc_device_data *data = usb_get_intfdata(intf);

	if (count < 1)
		return -EINVAL;
	data->TermChar = buf[0];
	return count;
}
static DEVICE_ATTR(TermChar, S_IRUGO, show_TermChar, store_TermChar);

#define data_attribute(name)						\
static ssize_t show_##name(struct device *dev,				\
			   struct device_attribute *attr, char *buf)	\
{									\
	struct usb_interface *intf = to_usb_interface(dev);		\
	struct usbtmc_device_data *data = usb_get_intfdata(intf);	\
									\
	return sprintf(buf, "%d\n", data->name);			\
}									\
static ssize_t store_##name(struct device *dev,				\
			    struct device_attribute *attr,		\
			    const char *buf, size_t count)		\
{									\
	struct usb_interface *intf = to_usb_interface(dev);		\
	struct usbtmc_device_data *data = usb_get_intfdata(intf);	\
	ssize_t result;							\
	unsigned val;							\
									\
	result = sscanf(buf, "%u\n", &val);				\
	if (result != 1)						\
		result = -EINVAL;					\
	data->name = val;						\
	if (result < 0)							\
		return result;						\
	else								\
		return count;						\
}									\
static DEVICE_ATTR(name, S_IRUGO, show_##name, store_##name)

data_attribute(TermCharEnabled);
data_attribute(auto_abort);

static struct attribute *data_attrs[] = {
	&dev_attr_TermChar.attr,
	&dev_attr_TermCharEnabled.attr,
	&dev_attr_auto_abort.attr,
	NULL,
};

static struct attribute_group data_attr_grp = {
	.attrs = data_attrs,
};

static int usbtmc_ioctl_indicator_pulse(struct usbtmc_device_data *data)
{
	struct device *dev;
	u8 *buffer;
	int rv;

	dev = &data->intf->dev;

	buffer = kmalloc(2, GFP_KERNEL);
	if (!buffer)
		return -ENOMEM;

	rv = usb_control_msg(data->usb_dev,
			     usb_rcvctrlpipe(data->usb_dev, 0),
			     USBTMC_REQUEST_INDICATOR_PULSE,
			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
			     0, 0, buffer, 0x01, USBTMC_TIMEOUT);

	if (rv < 0) {
		dev_err(dev, "usb_control_msg returned %d\n", rv);
		goto exit;
	}

	dev_dbg(dev, "INDICATOR_PULSE returned %x\n", buffer[0]);

	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
		dev_err(dev, "INDICATOR_PULSE returned %x\n", buffer[0]);
		rv = -EPERM;
		goto exit;
	}
	rv = 0;

exit:
	kfree(buffer);
	return rv;
}

static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	struct usbtmc_device_data *data;
	int retval = -EBADRQC;

	data = file->private_data;
	mutex_lock(&data->io_mutex);

	switch (cmd) {
	case USBTMC_IOCTL_CLEAR_OUT_HALT:
		retval = usbtmc_ioctl_clear_out_halt(data);
		break;

	case USBTMC_IOCTL_CLEAR_IN_HALT:
		retval = usbtmc_ioctl_clear_in_halt(data);
		break;

	case USBTMC_IOCTL_INDICATOR_PULSE:
		retval = usbtmc_ioctl_indicator_pulse(data);
		break;

	case USBTMC_IOCTL_CLEAR:
		retval = usbtmc_ioctl_clear(data);
		break;

	case USBTMC_IOCTL_ABORT_BULK_OUT:
		retval = usbtmc_ioctl_abort_bulk_out(data);
		break;

	case USBTMC_IOCTL_ABORT_BULK_IN:
		retval = usbtmc_ioctl_abort_bulk_in(data);
		break;
	}

	mutex_unlock(&data->io_mutex);
	return retval;
}

static struct file_operations fops = {
	.owner		= THIS_MODULE,
	.read		= usbtmc_read,
	.write		= usbtmc_write,
	.open		= usbtmc_open,
	.release	= usbtmc_release,
	.unlocked_ioctl	= usbtmc_ioctl,
};

static struct usb_class_driver usbtmc_class = {
	.name =		"usbtmc%d",
	.fops =		&fops,
	.minor_base =	USBTMC_MINOR_BASE,
};


static int usbtmc_probe(struct usb_interface *intf,
			const struct usb_device_id *id)
{
	struct usbtmc_device_data *data;
	struct usb_host_interface *iface_desc;
	struct usb_endpoint_descriptor *endpoint;
	int n;
	int retcode;

	dev_dbg(&intf->dev, "%s called\n", __func__);

	data = kmalloc(sizeof(struct usbtmc_device_data), GFP_KERNEL);
	if (!data) {
		dev_err(&intf->dev, "Unable to allocate kernel memory\n");
		return -ENOMEM;
	}

	data->intf = intf;
	data->id = id;
	data->usb_dev = usb_get_dev(interface_to_usbdev(intf));
	usb_set_intfdata(intf, data);
	kref_init(&data->kref);
	mutex_init(&data->io_mutex);

	/* Initialize USBTMC bTag and other fields */
	data->bTag	= 1;
	data->TermCharEnabled = 0;
	data->TermChar = '\n';

	/* USBTMC devices have only one setting, so use that */
	iface_desc = data->intf->cur_altsetting;

	/* Find bulk in endpoint */
	for (n = 0; n < iface_desc->desc.bNumEndpoints; n++) {
		endpoint = &iface_desc->endpoint[n].desc;

		if (usb_endpoint_is_bulk_in(endpoint)) {
			data->bulk_in = endpoint->bEndpointAddress;
			dev_dbg(&intf->dev, "Found bulk in endpoint at %u\n",
				data->bulk_in);
			break;
		}
	}

	/* Find bulk out endpoint */
	for (n = 0; n < iface_desc->desc.bNumEndpoints; n++) {
		endpoint = &iface_desc->endpoint[n].desc;

		if (usb_endpoint_is_bulk_out(endpoint)) {
			data->bulk_out = endpoint->bEndpointAddress;
			dev_dbg(&intf->dev, "Found Bulk out endpoint at %u\n",
				data->bulk_out);
			break;
		}
	}

	retcode = get_capabilities(data);
	if (retcode)
		dev_err(&intf->dev, "can't read capabilities\n");
	else
		retcode = sysfs_create_group(&intf->dev.kobj,
					     &capability_attr_grp);

	retcode = sysfs_create_group(&intf->dev.kobj, &data_attr_grp);

	retcode = usb_register_dev(intf, &usbtmc_class);
	if (retcode) {
		dev_err(&intf->dev, "Not able to get a minor"
			" (base %u, slice default): %d\n", USBTMC_MINOR_BASE,
			retcode);
		goto error_register;
	}
	dev_dbg(&intf->dev, "Using minor number %d\n", intf->minor);

	return 0;

error_register:
	sysfs_remove_group(&intf->dev.kobj, &capability_attr_grp);
	sysfs_remove_group(&intf->dev.kobj, &data_attr_grp);
	kref_put(&data->kref, usbtmc_delete);
	return retcode;
}

static void usbtmc_disconnect(struct usb_interface *intf)
{
	struct usbtmc_device_data *data;

	dev_dbg(&intf->dev, "usbtmc_disconnect called\n");

	data = usb_get_intfdata(intf);
	usb_deregister_dev(intf, &usbtmc_class);
	sysfs_remove_group(&intf->dev.kobj, &capability_attr_grp);
	sysfs_remove_group(&intf->dev.kobj, &data_attr_grp);
	kref_put(&data->kref, usbtmc_delete);
}

static struct usb_driver usbtmc_driver = {
	.name		= "usbtmc",
	.id_table	= usbtmc_devices,
	.probe		= usbtmc_probe,
	.disconnect	= usbtmc_disconnect
};

static int __init usbtmc_init(void)
{
	int retcode;

	retcode = usb_register(&usbtmc_driver);
	if (retcode)
		printk(KERN_ERR KBUILD_MODNAME": Unable to register driver\n");
	return retcode;
}
module_init(usbtmc_init);

static void __exit usbtmc_exit(void)
{
	usb_deregister(&usbtmc_driver);
}
module_exit(usbtmc_exit);

MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud