xref: /linux/drivers/usb/class/usbtmc.c (revision 5fd54ace4721fc5ce2bb5aef6318fcf17f421460)
1 // SPDX-License-Identifier: GPL-2.0+
2 /**
3  * drivers/usb/class/usbtmc.c - USB Test & Measurement class driver
4  *
5  * Copyright (C) 2007 Stefan Kopp, Gechingen, Germany
6  * Copyright (C) 2008 Novell, Inc.
7  * Copyright (C) 2008 Greg Kroah-Hartman <gregkh@suse.de>
8  *
9  * This program is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU General Public License
11  * as published by the Free Software Foundation; either version 2
12  * of the License, or (at your option) any later version.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  *
19  * The GNU General Public License is available at
20  * http://www.gnu.org/copyleft/gpl.html.
21  */
22 
23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
24 
25 #include <linux/module.h>
26 #include <linux/kernel.h>
27 #include <linux/fs.h>
28 #include <linux/uaccess.h>
29 #include <linux/kref.h>
30 #include <linux/slab.h>
31 #include <linux/poll.h>
32 #include <linux/mutex.h>
33 #include <linux/usb.h>
34 #include <linux/usb/tmc.h>
35 
36 
37 #define RIGOL			1
38 #define USBTMC_HEADER_SIZE	12
39 #define USBTMC_MINOR_BASE	176
40 
41 /*
42  * Size of driver internal IO buffer. Must be multiple of 4 and at least as
43  * large as wMaxPacketSize (which is usually 512 bytes).
44  */
45 #define USBTMC_SIZE_IOBUFFER	2048
46 
47 /* Default USB timeout (in milliseconds) */
48 #define USBTMC_TIMEOUT		5000
49 
50 /*
51  * Maximum number of read cycles to empty bulk in endpoint during CLEAR and
52  * ABORT_BULK_IN requests. Ends the loop if (for whatever reason) a short
53  * packet is never read.
54  */
55 #define USBTMC_MAX_READS_TO_CLEAR_BULK_IN	100
56 
57 static const struct usb_device_id usbtmc_devices[] = {
58 	{ USB_INTERFACE_INFO(USB_CLASS_APP_SPEC, 3, 0), },
59 	{ USB_INTERFACE_INFO(USB_CLASS_APP_SPEC, 3, 1), },
60 	{ 0, } /* terminating entry */
61 };
62 MODULE_DEVICE_TABLE(usb, usbtmc_devices);
63 
64 /*
65  * This structure is the capabilities for the device
66  * See section 4.2.1.8 of the USBTMC specification,
67  * and section 4.2.2 of the USBTMC usb488 subclass
68  * specification for details.
69  */
70 struct usbtmc_dev_capabilities {
71 	__u8 interface_capabilities;
72 	__u8 device_capabilities;
73 	__u8 usb488_interface_capabilities;
74 	__u8 usb488_device_capabilities;
75 };
76 
77 /* This structure holds private data for each USBTMC device. One copy is
78  * allocated for each USBTMC device in the driver's probe function.
79  */
80 struct usbtmc_device_data {
81 	const struct usb_device_id *id;
82 	struct usb_device *usb_dev;
83 	struct usb_interface *intf;
84 
85 	unsigned int bulk_in;
86 	unsigned int bulk_out;
87 
88 	u8 bTag;
89 	u8 bTag_last_write;	/* needed for abort */
90 	u8 bTag_last_read;	/* needed for abort */
91 
92 	/* data for interrupt in endpoint handling */
93 	u8             bNotify1;
94 	u8             bNotify2;
95 	u16            ifnum;
96 	u8             iin_bTag;
97 	u8            *iin_buffer;
98 	atomic_t       iin_data_valid;
99 	unsigned int   iin_ep;
100 	int            iin_ep_present;
101 	int            iin_interval;
102 	struct urb    *iin_urb;
103 	u16            iin_wMaxPacketSize;
104 	atomic_t       srq_asserted;
105 
106 	/* coalesced usb488_caps from usbtmc_dev_capabilities */
107 	__u8 usb488_caps;
108 
109 	u8 rigol_quirk;
110 
111 	/* attributes from the USB TMC spec for this device */
112 	u8 TermChar;
113 	bool TermCharEnabled;
114 	bool auto_abort;
115 
116 	bool zombie; /* fd of disconnected device */
117 
118 	struct usbtmc_dev_capabilities	capabilities;
119 	struct kref kref;
120 	struct mutex io_mutex;	/* only one i/o function running at a time */
121 	wait_queue_head_t waitq;
122 	struct fasync_struct *fasync;
123 };
124 #define to_usbtmc_data(d) container_of(d, struct usbtmc_device_data, kref)
125 
126 struct usbtmc_ID_rigol_quirk {
127 	__u16 idVendor;
128 	__u16 idProduct;
129 };
130 
131 static const struct usbtmc_ID_rigol_quirk usbtmc_id_quirk[] = {
132 	{ 0x1ab1, 0x0588 },
133 	{ 0x1ab1, 0x04b0 },
134 	{ 0, 0 }
135 };
136 
137 /* Forward declarations */
138 static struct usb_driver usbtmc_driver;
139 
140 static void usbtmc_delete(struct kref *kref)
141 {
142 	struct usbtmc_device_data *data = to_usbtmc_data(kref);
143 
144 	usb_put_dev(data->usb_dev);
145 	kfree(data);
146 }
147 
148 static int usbtmc_open(struct inode *inode, struct file *filp)
149 {
150 	struct usb_interface *intf;
151 	struct usbtmc_device_data *data;
152 	int retval = 0;
153 
154 	intf = usb_find_interface(&usbtmc_driver, iminor(inode));
155 	if (!intf) {
156 		pr_err("can not find device for minor %d", iminor(inode));
157 		return -ENODEV;
158 	}
159 
160 	data = usb_get_intfdata(intf);
161 	/* Protect reference to data from file structure until release */
162 	kref_get(&data->kref);
163 
164 	/* Store pointer in file structure's private data field */
165 	filp->private_data = data;
166 
167 	return retval;
168 }
169 
170 static int usbtmc_release(struct inode *inode, struct file *file)
171 {
172 	struct usbtmc_device_data *data = file->private_data;
173 
174 	kref_put(&data->kref, usbtmc_delete);
175 	return 0;
176 }
177 
178 static int usbtmc_ioctl_abort_bulk_in(struct usbtmc_device_data *data)
179 {
180 	u8 *buffer;
181 	struct device *dev;
182 	int rv;
183 	int n;
184 	int actual;
185 	struct usb_host_interface *current_setting;
186 	int max_size;
187 
188 	dev = &data->intf->dev;
189 	buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
190 	if (!buffer)
191 		return -ENOMEM;
192 
193 	rv = usb_control_msg(data->usb_dev,
194 			     usb_rcvctrlpipe(data->usb_dev, 0),
195 			     USBTMC_REQUEST_INITIATE_ABORT_BULK_IN,
196 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
197 			     data->bTag_last_read, data->bulk_in,
198 			     buffer, 2, USBTMC_TIMEOUT);
199 
200 	if (rv < 0) {
201 		dev_err(dev, "usb_control_msg returned %d\n", rv);
202 		goto exit;
203 	}
204 
205 	dev_dbg(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
206 
207 	if (buffer[0] == USBTMC_STATUS_FAILED) {
208 		rv = 0;
209 		goto exit;
210 	}
211 
212 	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
213 		dev_err(dev, "INITIATE_ABORT_BULK_IN returned %x\n",
214 			buffer[0]);
215 		rv = -EPERM;
216 		goto exit;
217 	}
218 
219 	max_size = 0;
220 	current_setting = data->intf->cur_altsetting;
221 	for (n = 0; n < current_setting->desc.bNumEndpoints; n++)
222 		if (current_setting->endpoint[n].desc.bEndpointAddress ==
223 			data->bulk_in)
224 			max_size = usb_endpoint_maxp(&current_setting->endpoint[n].desc);
225 
226 	if (max_size == 0) {
227 		dev_err(dev, "Couldn't get wMaxPacketSize\n");
228 		rv = -EPERM;
229 		goto exit;
230 	}
231 
232 	dev_dbg(&data->intf->dev, "wMaxPacketSize is %d\n", max_size);
233 
234 	n = 0;
235 
236 	do {
237 		dev_dbg(dev, "Reading from bulk in EP\n");
238 
239 		rv = usb_bulk_msg(data->usb_dev,
240 				  usb_rcvbulkpipe(data->usb_dev,
241 						  data->bulk_in),
242 				  buffer, USBTMC_SIZE_IOBUFFER,
243 				  &actual, USBTMC_TIMEOUT);
244 
245 		n++;
246 
247 		if (rv < 0) {
248 			dev_err(dev, "usb_bulk_msg returned %d\n", rv);
249 			goto exit;
250 		}
251 	} while ((actual == max_size) &&
252 		 (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));
253 
254 	if (actual == max_size) {
255 		dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
256 			USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
257 		rv = -EPERM;
258 		goto exit;
259 	}
260 
261 	n = 0;
262 
263 usbtmc_abort_bulk_in_status:
264 	rv = usb_control_msg(data->usb_dev,
265 			     usb_rcvctrlpipe(data->usb_dev, 0),
266 			     USBTMC_REQUEST_CHECK_ABORT_BULK_IN_STATUS,
267 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
268 			     0, data->bulk_in, buffer, 0x08,
269 			     USBTMC_TIMEOUT);
270 
271 	if (rv < 0) {
272 		dev_err(dev, "usb_control_msg returned %d\n", rv);
273 		goto exit;
274 	}
275 
276 	dev_dbg(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
277 
278 	if (buffer[0] == USBTMC_STATUS_SUCCESS) {
279 		rv = 0;
280 		goto exit;
281 	}
282 
283 	if (buffer[0] != USBTMC_STATUS_PENDING) {
284 		dev_err(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
285 		rv = -EPERM;
286 		goto exit;
287 	}
288 
289 	if (buffer[1] == 1)
290 		do {
291 			dev_dbg(dev, "Reading from bulk in EP\n");
292 
293 			rv = usb_bulk_msg(data->usb_dev,
294 					  usb_rcvbulkpipe(data->usb_dev,
295 							  data->bulk_in),
296 					  buffer, USBTMC_SIZE_IOBUFFER,
297 					  &actual, USBTMC_TIMEOUT);
298 
299 			n++;
300 
301 			if (rv < 0) {
302 				dev_err(dev, "usb_bulk_msg returned %d\n", rv);
303 				goto exit;
304 			}
305 		} while ((actual == max_size) &&
306 			 (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));
307 
308 	if (actual == max_size) {
309 		dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
310 			USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
311 		rv = -EPERM;
312 		goto exit;
313 	}
314 
315 	goto usbtmc_abort_bulk_in_status;
316 
317 exit:
318 	kfree(buffer);
319 	return rv;
320 
321 }
322 
323 static int usbtmc_ioctl_abort_bulk_out(struct usbtmc_device_data *data)
324 {
325 	struct device *dev;
326 	u8 *buffer;
327 	int rv;
328 	int n;
329 
330 	dev = &data->intf->dev;
331 
332 	buffer = kmalloc(8, GFP_KERNEL);
333 	if (!buffer)
334 		return -ENOMEM;
335 
336 	rv = usb_control_msg(data->usb_dev,
337 			     usb_rcvctrlpipe(data->usb_dev, 0),
338 			     USBTMC_REQUEST_INITIATE_ABORT_BULK_OUT,
339 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
340 			     data->bTag_last_write, data->bulk_out,
341 			     buffer, 2, USBTMC_TIMEOUT);
342 
343 	if (rv < 0) {
344 		dev_err(dev, "usb_control_msg returned %d\n", rv);
345 		goto exit;
346 	}
347 
348 	dev_dbg(dev, "INITIATE_ABORT_BULK_OUT returned %x\n", buffer[0]);
349 
350 	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
351 		dev_err(dev, "INITIATE_ABORT_BULK_OUT returned %x\n",
352 			buffer[0]);
353 		rv = -EPERM;
354 		goto exit;
355 	}
356 
357 	n = 0;
358 
359 usbtmc_abort_bulk_out_check_status:
360 	rv = usb_control_msg(data->usb_dev,
361 			     usb_rcvctrlpipe(data->usb_dev, 0),
362 			     USBTMC_REQUEST_CHECK_ABORT_BULK_OUT_STATUS,
363 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
364 			     0, data->bulk_out, buffer, 0x08,
365 			     USBTMC_TIMEOUT);
366 	n++;
367 	if (rv < 0) {
368 		dev_err(dev, "usb_control_msg returned %d\n", rv);
369 		goto exit;
370 	}
371 
372 	dev_dbg(dev, "CHECK_ABORT_BULK_OUT returned %x\n", buffer[0]);
373 
374 	if (buffer[0] == USBTMC_STATUS_SUCCESS)
375 		goto usbtmc_abort_bulk_out_clear_halt;
376 
377 	if ((buffer[0] == USBTMC_STATUS_PENDING) &&
378 	    (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN))
379 		goto usbtmc_abort_bulk_out_check_status;
380 
381 	rv = -EPERM;
382 	goto exit;
383 
384 usbtmc_abort_bulk_out_clear_halt:
385 	rv = usb_clear_halt(data->usb_dev,
386 			    usb_sndbulkpipe(data->usb_dev, data->bulk_out));
387 
388 	if (rv < 0) {
389 		dev_err(dev, "usb_control_msg returned %d\n", rv);
390 		goto exit;
391 	}
392 	rv = 0;
393 
394 exit:
395 	kfree(buffer);
396 	return rv;
397 }
398 
399 static int usbtmc488_ioctl_read_stb(struct usbtmc_device_data *data,
400 				void __user *arg)
401 {
402 	struct device *dev = &data->intf->dev;
403 	u8 *buffer;
404 	u8 tag;
405 	__u8 stb;
406 	int rv;
407 
408 	dev_dbg(dev, "Enter ioctl_read_stb iin_ep_present: %d\n",
409 		data->iin_ep_present);
410 
411 	buffer = kmalloc(8, GFP_KERNEL);
412 	if (!buffer)
413 		return -ENOMEM;
414 
415 	atomic_set(&data->iin_data_valid, 0);
416 
417 	/* must issue read_stb before using poll or select */
418 	atomic_set(&data->srq_asserted, 0);
419 
420 	rv = usb_control_msg(data->usb_dev,
421 			usb_rcvctrlpipe(data->usb_dev, 0),
422 			USBTMC488_REQUEST_READ_STATUS_BYTE,
423 			USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
424 			data->iin_bTag,
425 			data->ifnum,
426 			buffer, 0x03, USBTMC_TIMEOUT);
427 	if (rv < 0) {
428 		dev_err(dev, "stb usb_control_msg returned %d\n", rv);
429 		goto exit;
430 	}
431 
432 	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
433 		dev_err(dev, "control status returned %x\n", buffer[0]);
434 		rv = -EIO;
435 		goto exit;
436 	}
437 
438 	if (data->iin_ep_present) {
439 		rv = wait_event_interruptible_timeout(
440 			data->waitq,
441 			atomic_read(&data->iin_data_valid) != 0,
442 			USBTMC_TIMEOUT);
443 		if (rv < 0) {
444 			dev_dbg(dev, "wait interrupted %d\n", rv);
445 			goto exit;
446 		}
447 
448 		if (rv == 0) {
449 			dev_dbg(dev, "wait timed out\n");
450 			rv = -ETIME;
451 			goto exit;
452 		}
453 
454 		tag = data->bNotify1 & 0x7f;
455 		if (tag != data->iin_bTag) {
456 			dev_err(dev, "expected bTag %x got %x\n",
457 				data->iin_bTag, tag);
458 		}
459 
460 		stb = data->bNotify2;
461 	} else {
462 		stb = buffer[2];
463 	}
464 
465 	rv = copy_to_user(arg, &stb, sizeof(stb));
466 	if (rv)
467 		rv = -EFAULT;
468 
469  exit:
470 	/* bump interrupt bTag */
471 	data->iin_bTag += 1;
472 	if (data->iin_bTag > 127)
473 		/* 1 is for SRQ see USBTMC-USB488 subclass spec section 4.3.1 */
474 		data->iin_bTag = 2;
475 
476 	kfree(buffer);
477 	return rv;
478 }
479 
480 static int usbtmc488_ioctl_simple(struct usbtmc_device_data *data,
481 				void __user *arg, unsigned int cmd)
482 {
483 	struct device *dev = &data->intf->dev;
484 	__u8 val;
485 	u8 *buffer;
486 	u16 wValue;
487 	int rv;
488 
489 	if (!(data->usb488_caps & USBTMC488_CAPABILITY_SIMPLE))
490 		return -EINVAL;
491 
492 	buffer = kmalloc(8, GFP_KERNEL);
493 	if (!buffer)
494 		return -ENOMEM;
495 
496 	if (cmd == USBTMC488_REQUEST_REN_CONTROL) {
497 		rv = copy_from_user(&val, arg, sizeof(val));
498 		if (rv) {
499 			rv = -EFAULT;
500 			goto exit;
501 		}
502 		wValue = val ? 1 : 0;
503 	} else {
504 		wValue = 0;
505 	}
506 
507 	rv = usb_control_msg(data->usb_dev,
508 			usb_rcvctrlpipe(data->usb_dev, 0),
509 			cmd,
510 			USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
511 			wValue,
512 			data->ifnum,
513 			buffer, 0x01, USBTMC_TIMEOUT);
514 	if (rv < 0) {
515 		dev_err(dev, "simple usb_control_msg failed %d\n", rv);
516 		goto exit;
517 	} else if (rv != 1) {
518 		dev_warn(dev, "simple usb_control_msg returned %d\n", rv);
519 		rv = -EIO;
520 		goto exit;
521 	}
522 
523 	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
524 		dev_err(dev, "simple control status returned %x\n", buffer[0]);
525 		rv = -EIO;
526 		goto exit;
527 	}
528 	rv = 0;
529 
530  exit:
531 	kfree(buffer);
532 	return rv;
533 }
534 
535 /*
536  * Sends a REQUEST_DEV_DEP_MSG_IN message on the Bulk-OUT endpoint.
537  * @transfer_size: number of bytes to request from the device.
538  *
539  * See the USBTMC specification, Table 4.
540  *
541  * Also updates bTag_last_write.
542  */
543 static int send_request_dev_dep_msg_in(struct usbtmc_device_data *data, size_t transfer_size)
544 {
545 	int retval;
546 	u8 *buffer;
547 	int actual;
548 
549 	buffer = kmalloc(USBTMC_HEADER_SIZE, GFP_KERNEL);
550 	if (!buffer)
551 		return -ENOMEM;
552 	/* Setup IO buffer for REQUEST_DEV_DEP_MSG_IN message
553 	 * Refer to class specs for details
554 	 */
555 	buffer[0] = 2;
556 	buffer[1] = data->bTag;
557 	buffer[2] = ~data->bTag;
558 	buffer[3] = 0; /* Reserved */
559 	buffer[4] = transfer_size >> 0;
560 	buffer[5] = transfer_size >> 8;
561 	buffer[6] = transfer_size >> 16;
562 	buffer[7] = transfer_size >> 24;
563 	buffer[8] = data->TermCharEnabled * 2;
564 	/* Use term character? */
565 	buffer[9] = data->TermChar;
566 	buffer[10] = 0; /* Reserved */
567 	buffer[11] = 0; /* Reserved */
568 
569 	/* Send bulk URB */
570 	retval = usb_bulk_msg(data->usb_dev,
571 			      usb_sndbulkpipe(data->usb_dev,
572 					      data->bulk_out),
573 			      buffer, USBTMC_HEADER_SIZE, &actual, USBTMC_TIMEOUT);
574 
575 	/* Store bTag (in case we need to abort) */
576 	data->bTag_last_write = data->bTag;
577 
578 	/* Increment bTag -- and increment again if zero */
579 	data->bTag++;
580 	if (!data->bTag)
581 		data->bTag++;
582 
583 	kfree(buffer);
584 	if (retval < 0) {
585 		dev_err(&data->intf->dev, "usb_bulk_msg in send_request_dev_dep_msg_in() returned %d\n", retval);
586 		return retval;
587 	}
588 
589 	return 0;
590 }
591 
592 static ssize_t usbtmc_read(struct file *filp, char __user *buf,
593 			   size_t count, loff_t *f_pos)
594 {
595 	struct usbtmc_device_data *data;
596 	struct device *dev;
597 	u32 n_characters;
598 	u8 *buffer;
599 	int actual;
600 	size_t done;
601 	size_t remaining;
602 	int retval;
603 	size_t this_part;
604 
605 	/* Get pointer to private data structure */
606 	data = filp->private_data;
607 	dev = &data->intf->dev;
608 
609 	buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
610 	if (!buffer)
611 		return -ENOMEM;
612 
613 	mutex_lock(&data->io_mutex);
614 	if (data->zombie) {
615 		retval = -ENODEV;
616 		goto exit;
617 	}
618 
619 	if (data->rigol_quirk) {
620 		dev_dbg(dev, "usb_bulk_msg_in: count(%zu)\n", count);
621 
622 		retval = send_request_dev_dep_msg_in(data, count);
623 
624 		if (retval < 0) {
625 			if (data->auto_abort)
626 				usbtmc_ioctl_abort_bulk_out(data);
627 			goto exit;
628 		}
629 	}
630 
631 	/* Loop until we have fetched everything we requested */
632 	remaining = count;
633 	this_part = remaining;
634 	done = 0;
635 
636 	while (remaining > 0) {
637 		if (!data->rigol_quirk) {
638 			dev_dbg(dev, "usb_bulk_msg_in: remaining(%zu), count(%zu)\n", remaining, count);
639 
640 			if (remaining > USBTMC_SIZE_IOBUFFER - USBTMC_HEADER_SIZE - 3)
641 				this_part = USBTMC_SIZE_IOBUFFER - USBTMC_HEADER_SIZE - 3;
642 			else
643 				this_part = remaining;
644 
645 			retval = send_request_dev_dep_msg_in(data, this_part);
646 			if (retval < 0) {
647 			dev_err(dev, "usb_bulk_msg returned %d\n", retval);
648 				if (data->auto_abort)
649 					usbtmc_ioctl_abort_bulk_out(data);
650 				goto exit;
651 			}
652 		}
653 
654 		/* Send bulk URB */
655 		retval = usb_bulk_msg(data->usb_dev,
656 				      usb_rcvbulkpipe(data->usb_dev,
657 						      data->bulk_in),
658 				      buffer, USBTMC_SIZE_IOBUFFER, &actual,
659 				      USBTMC_TIMEOUT);
660 
661 		dev_dbg(dev, "usb_bulk_msg: retval(%u), done(%zu), remaining(%zu), actual(%d)\n", retval, done, remaining, actual);
662 
663 		/* Store bTag (in case we need to abort) */
664 		data->bTag_last_read = data->bTag;
665 
666 		if (retval < 0) {
667 			dev_dbg(dev, "Unable to read data, error %d\n", retval);
668 			if (data->auto_abort)
669 				usbtmc_ioctl_abort_bulk_in(data);
670 			goto exit;
671 		}
672 
673 		/* Parse header in first packet */
674 		if ((done == 0) || !data->rigol_quirk) {
675 			/* Sanity checks for the header */
676 			if (actual < USBTMC_HEADER_SIZE) {
677 				dev_err(dev, "Device sent too small first packet: %u < %u\n", actual, USBTMC_HEADER_SIZE);
678 				if (data->auto_abort)
679 					usbtmc_ioctl_abort_bulk_in(data);
680 				goto exit;
681 			}
682 
683 			if (buffer[0] != 2) {
684 				dev_err(dev, "Device sent reply with wrong MsgID: %u != 2\n", buffer[0]);
685 				if (data->auto_abort)
686 					usbtmc_ioctl_abort_bulk_in(data);
687 				goto exit;
688 			}
689 
690 			if (buffer[1] != data->bTag_last_write) {
691 				dev_err(dev, "Device sent reply with wrong bTag: %u != %u\n", buffer[1], data->bTag_last_write);
692 				if (data->auto_abort)
693 					usbtmc_ioctl_abort_bulk_in(data);
694 				goto exit;
695 			}
696 
697 			/* How many characters did the instrument send? */
698 			n_characters = buffer[4] +
699 				       (buffer[5] << 8) +
700 				       (buffer[6] << 16) +
701 				       (buffer[7] << 24);
702 
703 			if (n_characters > this_part) {
704 				dev_err(dev, "Device wants to return more data than requested: %u > %zu\n", n_characters, count);
705 				if (data->auto_abort)
706 					usbtmc_ioctl_abort_bulk_in(data);
707 				goto exit;
708 			}
709 
710 			/* Remove the USBTMC header */
711 			actual -= USBTMC_HEADER_SIZE;
712 
713 			/* Check if the message is smaller than requested */
714 			if (data->rigol_quirk) {
715 				if (remaining > n_characters)
716 					remaining = n_characters;
717 				/* Remove padding if it exists */
718 				if (actual > remaining)
719 					actual = remaining;
720 			}
721 			else {
722 				if (this_part > n_characters)
723 					this_part = n_characters;
724 				/* Remove padding if it exists */
725 				if (actual > this_part)
726 					actual = this_part;
727 			}
728 
729 			dev_dbg(dev, "Bulk-IN header: N_characters(%u), bTransAttr(%u)\n", n_characters, buffer[8]);
730 
731 			remaining -= actual;
732 
733 			/* Terminate if end-of-message bit received from device */
734 			if ((buffer[8] & 0x01) && (actual >= n_characters))
735 				remaining = 0;
736 
737 			dev_dbg(dev, "Bulk-IN header: remaining(%zu), buf(%p), buffer(%p) done(%zu)\n", remaining,buf,buffer,done);
738 
739 
740 			/* Copy buffer to user space */
741 			if (copy_to_user(buf + done, &buffer[USBTMC_HEADER_SIZE], actual)) {
742 				/* There must have been an addressing problem */
743 				retval = -EFAULT;
744 				goto exit;
745 			}
746 			done += actual;
747 		}
748 		else  {
749 			if (actual > remaining)
750 				actual = remaining;
751 
752 			remaining -= actual;
753 
754 			dev_dbg(dev, "Bulk-IN header cont: actual(%u), done(%zu), remaining(%zu), buf(%p), buffer(%p)\n", actual, done, remaining,buf,buffer);
755 
756 			/* Copy buffer to user space */
757 			if (copy_to_user(buf + done, buffer, actual)) {
758 				/* There must have been an addressing problem */
759 				retval = -EFAULT;
760 				goto exit;
761 			}
762 			done += actual;
763 		}
764 	}
765 
766 	/* Update file position value */
767 	*f_pos = *f_pos + done;
768 	retval = done;
769 
770 exit:
771 	mutex_unlock(&data->io_mutex);
772 	kfree(buffer);
773 	return retval;
774 }
775 
776 static ssize_t usbtmc_write(struct file *filp, const char __user *buf,
777 			    size_t count, loff_t *f_pos)
778 {
779 	struct usbtmc_device_data *data;
780 	u8 *buffer;
781 	int retval;
782 	int actual;
783 	unsigned long int n_bytes;
784 	int remaining;
785 	int done;
786 	int this_part;
787 
788 	data = filp->private_data;
789 
790 	buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
791 	if (!buffer)
792 		return -ENOMEM;
793 
794 	mutex_lock(&data->io_mutex);
795 	if (data->zombie) {
796 		retval = -ENODEV;
797 		goto exit;
798 	}
799 
800 	remaining = count;
801 	done = 0;
802 
803 	while (remaining > 0) {
804 		if (remaining > USBTMC_SIZE_IOBUFFER - USBTMC_HEADER_SIZE) {
805 			this_part = USBTMC_SIZE_IOBUFFER - USBTMC_HEADER_SIZE;
806 			buffer[8] = 0;
807 		} else {
808 			this_part = remaining;
809 			buffer[8] = 1;
810 		}
811 
812 		/* Setup IO buffer for DEV_DEP_MSG_OUT message */
813 		buffer[0] = 1;
814 		buffer[1] = data->bTag;
815 		buffer[2] = ~data->bTag;
816 		buffer[3] = 0; /* Reserved */
817 		buffer[4] = this_part >> 0;
818 		buffer[5] = this_part >> 8;
819 		buffer[6] = this_part >> 16;
820 		buffer[7] = this_part >> 24;
821 		/* buffer[8] is set above... */
822 		buffer[9] = 0; /* Reserved */
823 		buffer[10] = 0; /* Reserved */
824 		buffer[11] = 0; /* Reserved */
825 
826 		if (copy_from_user(&buffer[USBTMC_HEADER_SIZE], buf + done, this_part)) {
827 			retval = -EFAULT;
828 			goto exit;
829 		}
830 
831 		n_bytes = roundup(USBTMC_HEADER_SIZE + this_part, 4);
832 		memset(buffer + USBTMC_HEADER_SIZE + this_part, 0, n_bytes - (USBTMC_HEADER_SIZE + this_part));
833 
834 		do {
835 			retval = usb_bulk_msg(data->usb_dev,
836 					      usb_sndbulkpipe(data->usb_dev,
837 							      data->bulk_out),
838 					      buffer, n_bytes,
839 					      &actual, USBTMC_TIMEOUT);
840 			if (retval != 0)
841 				break;
842 			n_bytes -= actual;
843 		} while (n_bytes);
844 
845 		data->bTag_last_write = data->bTag;
846 		data->bTag++;
847 
848 		if (!data->bTag)
849 			data->bTag++;
850 
851 		if (retval < 0) {
852 			dev_err(&data->intf->dev,
853 				"Unable to send data, error %d\n", retval);
854 			if (data->auto_abort)
855 				usbtmc_ioctl_abort_bulk_out(data);
856 			goto exit;
857 		}
858 
859 		remaining -= this_part;
860 		done += this_part;
861 	}
862 
863 	retval = count;
864 exit:
865 	mutex_unlock(&data->io_mutex);
866 	kfree(buffer);
867 	return retval;
868 }
869 
870 static int usbtmc_ioctl_clear(struct usbtmc_device_data *data)
871 {
872 	struct usb_host_interface *current_setting;
873 	struct usb_endpoint_descriptor *desc;
874 	struct device *dev;
875 	u8 *buffer;
876 	int rv;
877 	int n;
878 	int actual = 0;
879 	int max_size;
880 
881 	dev = &data->intf->dev;
882 
883 	dev_dbg(dev, "Sending INITIATE_CLEAR request\n");
884 
885 	buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
886 	if (!buffer)
887 		return -ENOMEM;
888 
889 	rv = usb_control_msg(data->usb_dev,
890 			     usb_rcvctrlpipe(data->usb_dev, 0),
891 			     USBTMC_REQUEST_INITIATE_CLEAR,
892 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
893 			     0, 0, buffer, 1, USBTMC_TIMEOUT);
894 	if (rv < 0) {
895 		dev_err(dev, "usb_control_msg returned %d\n", rv);
896 		goto exit;
897 	}
898 
899 	dev_dbg(dev, "INITIATE_CLEAR returned %x\n", buffer[0]);
900 
901 	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
902 		dev_err(dev, "INITIATE_CLEAR returned %x\n", buffer[0]);
903 		rv = -EPERM;
904 		goto exit;
905 	}
906 
907 	max_size = 0;
908 	current_setting = data->intf->cur_altsetting;
909 	for (n = 0; n < current_setting->desc.bNumEndpoints; n++) {
910 		desc = &current_setting->endpoint[n].desc;
911 		if (desc->bEndpointAddress == data->bulk_in)
912 			max_size = usb_endpoint_maxp(desc);
913 	}
914 
915 	if (max_size == 0) {
916 		dev_err(dev, "Couldn't get wMaxPacketSize\n");
917 		rv = -EPERM;
918 		goto exit;
919 	}
920 
921 	dev_dbg(dev, "wMaxPacketSize is %d\n", max_size);
922 
923 	n = 0;
924 
925 usbtmc_clear_check_status:
926 
927 	dev_dbg(dev, "Sending CHECK_CLEAR_STATUS request\n");
928 
929 	rv = usb_control_msg(data->usb_dev,
930 			     usb_rcvctrlpipe(data->usb_dev, 0),
931 			     USBTMC_REQUEST_CHECK_CLEAR_STATUS,
932 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
933 			     0, 0, buffer, 2, USBTMC_TIMEOUT);
934 	if (rv < 0) {
935 		dev_err(dev, "usb_control_msg returned %d\n", rv);
936 		goto exit;
937 	}
938 
939 	dev_dbg(dev, "CHECK_CLEAR_STATUS returned %x\n", buffer[0]);
940 
941 	if (buffer[0] == USBTMC_STATUS_SUCCESS)
942 		goto usbtmc_clear_bulk_out_halt;
943 
944 	if (buffer[0] != USBTMC_STATUS_PENDING) {
945 		dev_err(dev, "CHECK_CLEAR_STATUS returned %x\n", buffer[0]);
946 		rv = -EPERM;
947 		goto exit;
948 	}
949 
950 	if (buffer[1] == 1)
951 		do {
952 			dev_dbg(dev, "Reading from bulk in EP\n");
953 
954 			rv = usb_bulk_msg(data->usb_dev,
955 					  usb_rcvbulkpipe(data->usb_dev,
956 							  data->bulk_in),
957 					  buffer, USBTMC_SIZE_IOBUFFER,
958 					  &actual, USBTMC_TIMEOUT);
959 			n++;
960 
961 			if (rv < 0) {
962 				dev_err(dev, "usb_control_msg returned %d\n",
963 					rv);
964 				goto exit;
965 			}
966 		} while ((actual == max_size) &&
967 			  (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));
968 
969 	if (actual == max_size) {
970 		dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
971 			USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
972 		rv = -EPERM;
973 		goto exit;
974 	}
975 
976 	goto usbtmc_clear_check_status;
977 
978 usbtmc_clear_bulk_out_halt:
979 
980 	rv = usb_clear_halt(data->usb_dev,
981 			    usb_sndbulkpipe(data->usb_dev, data->bulk_out));
982 	if (rv < 0) {
983 		dev_err(dev, "usb_control_msg returned %d\n", rv);
984 		goto exit;
985 	}
986 	rv = 0;
987 
988 exit:
989 	kfree(buffer);
990 	return rv;
991 }
992 
993 static int usbtmc_ioctl_clear_out_halt(struct usbtmc_device_data *data)
994 {
995 	int rv;
996 
997 	rv = usb_clear_halt(data->usb_dev,
998 			    usb_sndbulkpipe(data->usb_dev, data->bulk_out));
999 
1000 	if (rv < 0) {
1001 		dev_err(&data->usb_dev->dev, "usb_control_msg returned %d\n",
1002 			rv);
1003 		return rv;
1004 	}
1005 	return 0;
1006 }
1007 
1008 static int usbtmc_ioctl_clear_in_halt(struct usbtmc_device_data *data)
1009 {
1010 	int rv;
1011 
1012 	rv = usb_clear_halt(data->usb_dev,
1013 			    usb_rcvbulkpipe(data->usb_dev, data->bulk_in));
1014 
1015 	if (rv < 0) {
1016 		dev_err(&data->usb_dev->dev, "usb_control_msg returned %d\n",
1017 			rv);
1018 		return rv;
1019 	}
1020 	return 0;
1021 }
1022 
1023 static int get_capabilities(struct usbtmc_device_data *data)
1024 {
1025 	struct device *dev = &data->usb_dev->dev;
1026 	char *buffer;
1027 	int rv = 0;
1028 
1029 	buffer = kmalloc(0x18, GFP_KERNEL);
1030 	if (!buffer)
1031 		return -ENOMEM;
1032 
1033 	rv = usb_control_msg(data->usb_dev, usb_rcvctrlpipe(data->usb_dev, 0),
1034 			     USBTMC_REQUEST_GET_CAPABILITIES,
1035 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
1036 			     0, 0, buffer, 0x18, USBTMC_TIMEOUT);
1037 	if (rv < 0) {
1038 		dev_err(dev, "usb_control_msg returned %d\n", rv);
1039 		goto err_out;
1040 	}
1041 
1042 	dev_dbg(dev, "GET_CAPABILITIES returned %x\n", buffer[0]);
1043 	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
1044 		dev_err(dev, "GET_CAPABILITIES returned %x\n", buffer[0]);
1045 		rv = -EPERM;
1046 		goto err_out;
1047 	}
1048 	dev_dbg(dev, "Interface capabilities are %x\n", buffer[4]);
1049 	dev_dbg(dev, "Device capabilities are %x\n", buffer[5]);
1050 	dev_dbg(dev, "USB488 interface capabilities are %x\n", buffer[14]);
1051 	dev_dbg(dev, "USB488 device capabilities are %x\n", buffer[15]);
1052 
1053 	data->capabilities.interface_capabilities = buffer[4];
1054 	data->capabilities.device_capabilities = buffer[5];
1055 	data->capabilities.usb488_interface_capabilities = buffer[14];
1056 	data->capabilities.usb488_device_capabilities = buffer[15];
1057 	data->usb488_caps = (buffer[14] & 0x07) | ((buffer[15] & 0x0f) << 4);
1058 	rv = 0;
1059 
1060 err_out:
1061 	kfree(buffer);
1062 	return rv;
1063 }
1064 
1065 #define capability_attribute(name)					\
1066 static ssize_t name##_show(struct device *dev,				\
1067 			   struct device_attribute *attr, char *buf)	\
1068 {									\
1069 	struct usb_interface *intf = to_usb_interface(dev);		\
1070 	struct usbtmc_device_data *data = usb_get_intfdata(intf);	\
1071 									\
1072 	return sprintf(buf, "%d\n", data->capabilities.name);		\
1073 }									\
1074 static DEVICE_ATTR_RO(name)
1075 
1076 capability_attribute(interface_capabilities);
1077 capability_attribute(device_capabilities);
1078 capability_attribute(usb488_interface_capabilities);
1079 capability_attribute(usb488_device_capabilities);
1080 
1081 static struct attribute *capability_attrs[] = {
1082 	&dev_attr_interface_capabilities.attr,
1083 	&dev_attr_device_capabilities.attr,
1084 	&dev_attr_usb488_interface_capabilities.attr,
1085 	&dev_attr_usb488_device_capabilities.attr,
1086 	NULL,
1087 };
1088 
1089 static const struct attribute_group capability_attr_grp = {
1090 	.attrs = capability_attrs,
1091 };
1092 
1093 static ssize_t TermChar_show(struct device *dev,
1094 			     struct device_attribute *attr, char *buf)
1095 {
1096 	struct usb_interface *intf = to_usb_interface(dev);
1097 	struct usbtmc_device_data *data = usb_get_intfdata(intf);
1098 
1099 	return sprintf(buf, "%c\n", data->TermChar);
1100 }
1101 
1102 static ssize_t TermChar_store(struct device *dev,
1103 			      struct device_attribute *attr,
1104 			      const char *buf, size_t count)
1105 {
1106 	struct usb_interface *intf = to_usb_interface(dev);
1107 	struct usbtmc_device_data *data = usb_get_intfdata(intf);
1108 
1109 	if (count < 1)
1110 		return -EINVAL;
1111 	data->TermChar = buf[0];
1112 	return count;
1113 }
1114 static DEVICE_ATTR_RW(TermChar);
1115 
1116 #define data_attribute(name)						\
1117 static ssize_t name##_show(struct device *dev,				\
1118 			   struct device_attribute *attr, char *buf)	\
1119 {									\
1120 	struct usb_interface *intf = to_usb_interface(dev);		\
1121 	struct usbtmc_device_data *data = usb_get_intfdata(intf);	\
1122 									\
1123 	return sprintf(buf, "%d\n", data->name);			\
1124 }									\
1125 static ssize_t name##_store(struct device *dev,				\
1126 			    struct device_attribute *attr,		\
1127 			    const char *buf, size_t count)		\
1128 {									\
1129 	struct usb_interface *intf = to_usb_interface(dev);		\
1130 	struct usbtmc_device_data *data = usb_get_intfdata(intf);	\
1131 	ssize_t result;							\
1132 	unsigned val;							\
1133 									\
1134 	result = sscanf(buf, "%u\n", &val);				\
1135 	if (result != 1)						\
1136 		result = -EINVAL;					\
1137 	data->name = val;						\
1138 	if (result < 0)							\
1139 		return result;						\
1140 	else								\
1141 		return count;						\
1142 }									\
1143 static DEVICE_ATTR_RW(name)
1144 
1145 data_attribute(TermCharEnabled);
1146 data_attribute(auto_abort);
1147 
1148 static struct attribute *data_attrs[] = {
1149 	&dev_attr_TermChar.attr,
1150 	&dev_attr_TermCharEnabled.attr,
1151 	&dev_attr_auto_abort.attr,
1152 	NULL,
1153 };
1154 
1155 static const struct attribute_group data_attr_grp = {
1156 	.attrs = data_attrs,
1157 };
1158 
1159 static int usbtmc_ioctl_indicator_pulse(struct usbtmc_device_data *data)
1160 {
1161 	struct device *dev;
1162 	u8 *buffer;
1163 	int rv;
1164 
1165 	dev = &data->intf->dev;
1166 
1167 	buffer = kmalloc(2, GFP_KERNEL);
1168 	if (!buffer)
1169 		return -ENOMEM;
1170 
1171 	rv = usb_control_msg(data->usb_dev,
1172 			     usb_rcvctrlpipe(data->usb_dev, 0),
1173 			     USBTMC_REQUEST_INDICATOR_PULSE,
1174 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
1175 			     0, 0, buffer, 0x01, USBTMC_TIMEOUT);
1176 
1177 	if (rv < 0) {
1178 		dev_err(dev, "usb_control_msg returned %d\n", rv);
1179 		goto exit;
1180 	}
1181 
1182 	dev_dbg(dev, "INDICATOR_PULSE returned %x\n", buffer[0]);
1183 
1184 	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
1185 		dev_err(dev, "INDICATOR_PULSE returned %x\n", buffer[0]);
1186 		rv = -EPERM;
1187 		goto exit;
1188 	}
1189 	rv = 0;
1190 
1191 exit:
1192 	kfree(buffer);
1193 	return rv;
1194 }
1195 
1196 static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1197 {
1198 	struct usbtmc_device_data *data;
1199 	int retval = -EBADRQC;
1200 
1201 	data = file->private_data;
1202 	mutex_lock(&data->io_mutex);
1203 	if (data->zombie) {
1204 		retval = -ENODEV;
1205 		goto skip_io_on_zombie;
1206 	}
1207 
1208 	switch (cmd) {
1209 	case USBTMC_IOCTL_CLEAR_OUT_HALT:
1210 		retval = usbtmc_ioctl_clear_out_halt(data);
1211 		break;
1212 
1213 	case USBTMC_IOCTL_CLEAR_IN_HALT:
1214 		retval = usbtmc_ioctl_clear_in_halt(data);
1215 		break;
1216 
1217 	case USBTMC_IOCTL_INDICATOR_PULSE:
1218 		retval = usbtmc_ioctl_indicator_pulse(data);
1219 		break;
1220 
1221 	case USBTMC_IOCTL_CLEAR:
1222 		retval = usbtmc_ioctl_clear(data);
1223 		break;
1224 
1225 	case USBTMC_IOCTL_ABORT_BULK_OUT:
1226 		retval = usbtmc_ioctl_abort_bulk_out(data);
1227 		break;
1228 
1229 	case USBTMC_IOCTL_ABORT_BULK_IN:
1230 		retval = usbtmc_ioctl_abort_bulk_in(data);
1231 		break;
1232 
1233 	case USBTMC488_IOCTL_GET_CAPS:
1234 		retval = copy_to_user((void __user *)arg,
1235 				&data->usb488_caps,
1236 				sizeof(data->usb488_caps));
1237 		if (retval)
1238 			retval = -EFAULT;
1239 		break;
1240 
1241 	case USBTMC488_IOCTL_READ_STB:
1242 		retval = usbtmc488_ioctl_read_stb(data, (void __user *)arg);
1243 		break;
1244 
1245 	case USBTMC488_IOCTL_REN_CONTROL:
1246 		retval = usbtmc488_ioctl_simple(data, (void __user *)arg,
1247 						USBTMC488_REQUEST_REN_CONTROL);
1248 		break;
1249 
1250 	case USBTMC488_IOCTL_GOTO_LOCAL:
1251 		retval = usbtmc488_ioctl_simple(data, (void __user *)arg,
1252 						USBTMC488_REQUEST_GOTO_LOCAL);
1253 		break;
1254 
1255 	case USBTMC488_IOCTL_LOCAL_LOCKOUT:
1256 		retval = usbtmc488_ioctl_simple(data, (void __user *)arg,
1257 						USBTMC488_REQUEST_LOCAL_LOCKOUT);
1258 		break;
1259 	}
1260 
1261 skip_io_on_zombie:
1262 	mutex_unlock(&data->io_mutex);
1263 	return retval;
1264 }
1265 
1266 static int usbtmc_fasync(int fd, struct file *file, int on)
1267 {
1268 	struct usbtmc_device_data *data = file->private_data;
1269 
1270 	return fasync_helper(fd, file, on, &data->fasync);
1271 }
1272 
1273 static unsigned int usbtmc_poll(struct file *file, poll_table *wait)
1274 {
1275 	struct usbtmc_device_data *data = file->private_data;
1276 	unsigned int mask;
1277 
1278 	mutex_lock(&data->io_mutex);
1279 
1280 	if (data->zombie) {
1281 		mask = POLLHUP | POLLERR;
1282 		goto no_poll;
1283 	}
1284 
1285 	poll_wait(file, &data->waitq, wait);
1286 
1287 	mask = (atomic_read(&data->srq_asserted)) ? POLLIN | POLLRDNORM : 0;
1288 
1289 no_poll:
1290 	mutex_unlock(&data->io_mutex);
1291 	return mask;
1292 }
1293 
1294 static const struct file_operations fops = {
1295 	.owner		= THIS_MODULE,
1296 	.read		= usbtmc_read,
1297 	.write		= usbtmc_write,
1298 	.open		= usbtmc_open,
1299 	.release	= usbtmc_release,
1300 	.unlocked_ioctl	= usbtmc_ioctl,
1301 	.fasync         = usbtmc_fasync,
1302 	.poll           = usbtmc_poll,
1303 	.llseek		= default_llseek,
1304 };
1305 
1306 static struct usb_class_driver usbtmc_class = {
1307 	.name =		"usbtmc%d",
1308 	.fops =		&fops,
1309 	.minor_base =	USBTMC_MINOR_BASE,
1310 };
1311 
1312 static void usbtmc_interrupt(struct urb *urb)
1313 {
1314 	struct usbtmc_device_data *data = urb->context;
1315 	struct device *dev = &data->intf->dev;
1316 	int status = urb->status;
1317 	int rv;
1318 
1319 	dev_dbg(&data->intf->dev, "int status: %d len %d\n",
1320 		status, urb->actual_length);
1321 
1322 	switch (status) {
1323 	case 0: /* SUCCESS */
1324 		/* check for valid STB notification */
1325 		if (data->iin_buffer[0] > 0x81) {
1326 			data->bNotify1 = data->iin_buffer[0];
1327 			data->bNotify2 = data->iin_buffer[1];
1328 			atomic_set(&data->iin_data_valid, 1);
1329 			wake_up_interruptible(&data->waitq);
1330 			goto exit;
1331 		}
1332 		/* check for SRQ notification */
1333 		if (data->iin_buffer[0] == 0x81) {
1334 			if (data->fasync)
1335 				kill_fasync(&data->fasync,
1336 					SIGIO, POLL_IN);
1337 
1338 			atomic_set(&data->srq_asserted, 1);
1339 			wake_up_interruptible(&data->waitq);
1340 			goto exit;
1341 		}
1342 		dev_warn(dev, "invalid notification: %x\n", data->iin_buffer[0]);
1343 		break;
1344 	case -EOVERFLOW:
1345 		dev_err(dev, "overflow with length %d, actual length is %d\n",
1346 			data->iin_wMaxPacketSize, urb->actual_length);
1347 		/* fall through */
1348 	case -ECONNRESET:
1349 	case -ENOENT:
1350 	case -ESHUTDOWN:
1351 	case -EILSEQ:
1352 	case -ETIME:
1353 		/* urb terminated, clean up */
1354 		dev_dbg(dev, "urb terminated, status: %d\n", status);
1355 		return;
1356 	default:
1357 		dev_err(dev, "unknown status received: %d\n", status);
1358 	}
1359 exit:
1360 	rv = usb_submit_urb(urb, GFP_ATOMIC);
1361 	if (rv)
1362 		dev_err(dev, "usb_submit_urb failed: %d\n", rv);
1363 }
1364 
1365 static void usbtmc_free_int(struct usbtmc_device_data *data)
1366 {
1367 	if (!data->iin_ep_present || !data->iin_urb)
1368 		return;
1369 	usb_kill_urb(data->iin_urb);
1370 	kfree(data->iin_buffer);
1371 	usb_free_urb(data->iin_urb);
1372 	kref_put(&data->kref, usbtmc_delete);
1373 }
1374 
1375 static int usbtmc_probe(struct usb_interface *intf,
1376 			const struct usb_device_id *id)
1377 {
1378 	struct usbtmc_device_data *data;
1379 	struct usb_host_interface *iface_desc;
1380 	struct usb_endpoint_descriptor *bulk_in, *bulk_out, *int_in;
1381 	int n;
1382 	int retcode;
1383 
1384 	dev_dbg(&intf->dev, "%s called\n", __func__);
1385 
1386 	data = kzalloc(sizeof(*data), GFP_KERNEL);
1387 	if (!data)
1388 		return -ENOMEM;
1389 
1390 	data->intf = intf;
1391 	data->id = id;
1392 	data->usb_dev = usb_get_dev(interface_to_usbdev(intf));
1393 	usb_set_intfdata(intf, data);
1394 	kref_init(&data->kref);
1395 	mutex_init(&data->io_mutex);
1396 	init_waitqueue_head(&data->waitq);
1397 	atomic_set(&data->iin_data_valid, 0);
1398 	atomic_set(&data->srq_asserted, 0);
1399 	data->zombie = 0;
1400 
1401 	/* Determine if it is a Rigol or not */
1402 	data->rigol_quirk = 0;
1403 	dev_dbg(&intf->dev, "Trying to find if device Vendor 0x%04X Product 0x%04X has the RIGOL quirk\n",
1404 		le16_to_cpu(data->usb_dev->descriptor.idVendor),
1405 		le16_to_cpu(data->usb_dev->descriptor.idProduct));
1406 	for(n = 0; usbtmc_id_quirk[n].idVendor > 0; n++) {
1407 		if ((usbtmc_id_quirk[n].idVendor == le16_to_cpu(data->usb_dev->descriptor.idVendor)) &&
1408 		    (usbtmc_id_quirk[n].idProduct == le16_to_cpu(data->usb_dev->descriptor.idProduct))) {
1409 			dev_dbg(&intf->dev, "Setting this device as having the RIGOL quirk\n");
1410 			data->rigol_quirk = 1;
1411 			break;
1412 		}
1413 	}
1414 
1415 	/* Initialize USBTMC bTag and other fields */
1416 	data->bTag	= 1;
1417 	data->TermCharEnabled = 0;
1418 	data->TermChar = '\n';
1419 	/*  2 <= bTag <= 127   USBTMC-USB488 subclass specification 4.3.1 */
1420 	data->iin_bTag = 2;
1421 
1422 	/* USBTMC devices have only one setting, so use that */
1423 	iface_desc = data->intf->cur_altsetting;
1424 	data->ifnum = iface_desc->desc.bInterfaceNumber;
1425 
1426 	/* Find bulk endpoints */
1427 	retcode = usb_find_common_endpoints(iface_desc,
1428 			&bulk_in, &bulk_out, NULL, NULL);
1429 	if (retcode) {
1430 		dev_err(&intf->dev, "bulk endpoints not found\n");
1431 		goto err_put;
1432 	}
1433 
1434 	data->bulk_in = bulk_in->bEndpointAddress;
1435 	dev_dbg(&intf->dev, "Found bulk in endpoint at %u\n", data->bulk_in);
1436 
1437 	data->bulk_out = bulk_out->bEndpointAddress;
1438 	dev_dbg(&intf->dev, "Found Bulk out endpoint at %u\n", data->bulk_out);
1439 
1440 	/* Find int endpoint */
1441 	retcode = usb_find_int_in_endpoint(iface_desc, &int_in);
1442 	if (!retcode) {
1443 		data->iin_ep_present = 1;
1444 		data->iin_ep = int_in->bEndpointAddress;
1445 		data->iin_wMaxPacketSize = usb_endpoint_maxp(int_in);
1446 		data->iin_interval = int_in->bInterval;
1447 		dev_dbg(&intf->dev, "Found Int in endpoint at %u\n",
1448 				data->iin_ep);
1449 	}
1450 
1451 	retcode = get_capabilities(data);
1452 	if (retcode)
1453 		dev_err(&intf->dev, "can't read capabilities\n");
1454 	else
1455 		retcode = sysfs_create_group(&intf->dev.kobj,
1456 					     &capability_attr_grp);
1457 
1458 	if (data->iin_ep_present) {
1459 		/* allocate int urb */
1460 		data->iin_urb = usb_alloc_urb(0, GFP_KERNEL);
1461 		if (!data->iin_urb) {
1462 			retcode = -ENOMEM;
1463 			goto error_register;
1464 		}
1465 
1466 		/* Protect interrupt in endpoint data until iin_urb is freed */
1467 		kref_get(&data->kref);
1468 
1469 		/* allocate buffer for interrupt in */
1470 		data->iin_buffer = kmalloc(data->iin_wMaxPacketSize,
1471 					GFP_KERNEL);
1472 		if (!data->iin_buffer) {
1473 			retcode = -ENOMEM;
1474 			goto error_register;
1475 		}
1476 
1477 		/* fill interrupt urb */
1478 		usb_fill_int_urb(data->iin_urb, data->usb_dev,
1479 				usb_rcvintpipe(data->usb_dev, data->iin_ep),
1480 				data->iin_buffer, data->iin_wMaxPacketSize,
1481 				usbtmc_interrupt,
1482 				data, data->iin_interval);
1483 
1484 		retcode = usb_submit_urb(data->iin_urb, GFP_KERNEL);
1485 		if (retcode) {
1486 			dev_err(&intf->dev, "Failed to submit iin_urb\n");
1487 			goto error_register;
1488 		}
1489 	}
1490 
1491 	retcode = sysfs_create_group(&intf->dev.kobj, &data_attr_grp);
1492 
1493 	retcode = usb_register_dev(intf, &usbtmc_class);
1494 	if (retcode) {
1495 		dev_err(&intf->dev, "Not able to get a minor"
1496 			" (base %u, slice default): %d\n", USBTMC_MINOR_BASE,
1497 			retcode);
1498 		goto error_register;
1499 	}
1500 	dev_dbg(&intf->dev, "Using minor number %d\n", intf->minor);
1501 
1502 	return 0;
1503 
1504 error_register:
1505 	sysfs_remove_group(&intf->dev.kobj, &capability_attr_grp);
1506 	sysfs_remove_group(&intf->dev.kobj, &data_attr_grp);
1507 	usbtmc_free_int(data);
1508 err_put:
1509 	kref_put(&data->kref, usbtmc_delete);
1510 	return retcode;
1511 }
1512 
1513 static void usbtmc_disconnect(struct usb_interface *intf)
1514 {
1515 	struct usbtmc_device_data *data;
1516 
1517 	dev_dbg(&intf->dev, "usbtmc_disconnect called\n");
1518 
1519 	data = usb_get_intfdata(intf);
1520 	usb_deregister_dev(intf, &usbtmc_class);
1521 	sysfs_remove_group(&intf->dev.kobj, &capability_attr_grp);
1522 	sysfs_remove_group(&intf->dev.kobj, &data_attr_grp);
1523 	mutex_lock(&data->io_mutex);
1524 	data->zombie = 1;
1525 	wake_up_all(&data->waitq);
1526 	mutex_unlock(&data->io_mutex);
1527 	usbtmc_free_int(data);
1528 	kref_put(&data->kref, usbtmc_delete);
1529 }
1530 
1531 static int usbtmc_suspend(struct usb_interface *intf, pm_message_t message)
1532 {
1533 	/* this driver does not have pending URBs */
1534 	return 0;
1535 }
1536 
1537 static int usbtmc_resume(struct usb_interface *intf)
1538 {
1539 	return 0;
1540 }
1541 
1542 static struct usb_driver usbtmc_driver = {
1543 	.name		= "usbtmc",
1544 	.id_table	= usbtmc_devices,
1545 	.probe		= usbtmc_probe,
1546 	.disconnect	= usbtmc_disconnect,
1547 	.suspend	= usbtmc_suspend,
1548 	.resume		= usbtmc_resume,
1549 };
1550 
1551 module_usb_driver(usbtmc_driver);
1552 
1553 MODULE_LICENSE("GPL");
1554