xref: /linux/drivers/usb/class/usbtmc.c (revision 827634added7f38b7d724cab1dccdb2b004c13c3)
1 /**
2  * drivers/usb/class/usbtmc.c - USB Test & Measurement class driver
3  *
4  * Copyright (C) 2007 Stefan Kopp, Gechingen, Germany
5  * Copyright (C) 2008 Novell, Inc.
6  * Copyright (C) 2008 Greg Kroah-Hartman <gregkh@suse.de>
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License
10  * as published by the Free Software Foundation; either version 2
11  * of the License, or (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * The GNU General Public License is available at
19  * http://www.gnu.org/copyleft/gpl.html.
20  */
21 
22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23 
24 #include <linux/module.h>
25 #include <linux/kernel.h>
26 #include <linux/fs.h>
27 #include <linux/uaccess.h>
28 #include <linux/kref.h>
29 #include <linux/slab.h>
30 #include <linux/mutex.h>
31 #include <linux/usb.h>
32 #include <linux/usb/tmc.h>
33 
34 
35 #define RIGOL			1
36 #define USBTMC_HEADER_SIZE	12
37 #define USBTMC_MINOR_BASE	176
38 
39 /*
40  * Size of driver internal IO buffer. Must be multiple of 4 and at least as
41  * large as wMaxPacketSize (which is usually 512 bytes).
42  */
43 #define USBTMC_SIZE_IOBUFFER	2048
44 
45 /* Default USB timeout (in milliseconds) */
46 #define USBTMC_TIMEOUT		5000
47 
48 /*
49  * Maximum number of read cycles to empty bulk in endpoint during CLEAR and
50  * ABORT_BULK_IN requests. Ends the loop if (for whatever reason) a short
51  * packet is never read.
52  */
53 #define USBTMC_MAX_READS_TO_CLEAR_BULK_IN	100
54 
55 static const struct usb_device_id usbtmc_devices[] = {
56 	{ USB_INTERFACE_INFO(USB_CLASS_APP_SPEC, 3, 0), },
57 	{ USB_INTERFACE_INFO(USB_CLASS_APP_SPEC, 3, 1), },
58 	{ 0, } /* terminating entry */
59 };
60 MODULE_DEVICE_TABLE(usb, usbtmc_devices);
61 
62 /*
63  * This structure is the capabilities for the device
64  * See section 4.2.1.8 of the USBTMC specification,
65  * and section 4.2.2 of the USBTMC usb488 subclass
66  * specification for details.
67  */
68 struct usbtmc_dev_capabilities {
69 	__u8 interface_capabilities;
70 	__u8 device_capabilities;
71 	__u8 usb488_interface_capabilities;
72 	__u8 usb488_device_capabilities;
73 };
74 
75 /* This structure holds private data for each USBTMC device. One copy is
76  * allocated for each USBTMC device in the driver's probe function.
77  */
78 struct usbtmc_device_data {
79 	const struct usb_device_id *id;
80 	struct usb_device *usb_dev;
81 	struct usb_interface *intf;
82 
83 	unsigned int bulk_in;
84 	unsigned int bulk_out;
85 
86 	u8 bTag;
87 	u8 bTag_last_write;	/* needed for abort */
88 	u8 bTag_last_read;	/* needed for abort */
89 
90 	u8 rigol_quirk;
91 
92 	/* attributes from the USB TMC spec for this device */
93 	u8 TermChar;
94 	bool TermCharEnabled;
95 	bool auto_abort;
96 
97 	bool zombie; /* fd of disconnected device */
98 
99 	struct usbtmc_dev_capabilities	capabilities;
100 	struct kref kref;
101 	struct mutex io_mutex;	/* only one i/o function running at a time */
102 };
103 #define to_usbtmc_data(d) container_of(d, struct usbtmc_device_data, kref)
104 
105 struct usbtmc_ID_rigol_quirk {
106 	__u16 idVendor;
107 	__u16 idProduct;
108 };
109 
110 static const struct usbtmc_ID_rigol_quirk usbtmc_id_quirk[] = {
111 	{ 0x1ab1, 0x0588 },
112 	{ 0, 0 }
113 };
114 
115 /* Forward declarations */
116 static struct usb_driver usbtmc_driver;
117 
118 static void usbtmc_delete(struct kref *kref)
119 {
120 	struct usbtmc_device_data *data = to_usbtmc_data(kref);
121 
122 	usb_put_dev(data->usb_dev);
123 }
124 
125 static int usbtmc_open(struct inode *inode, struct file *filp)
126 {
127 	struct usb_interface *intf;
128 	struct usbtmc_device_data *data;
129 	int retval = 0;
130 
131 	intf = usb_find_interface(&usbtmc_driver, iminor(inode));
132 	if (!intf) {
133 		pr_err("can not find device for minor %d", iminor(inode));
134 		return -ENODEV;
135 	}
136 
137 	data = usb_get_intfdata(intf);
138 	kref_get(&data->kref);
139 
140 	/* Store pointer in file structure's private data field */
141 	filp->private_data = data;
142 
143 	return retval;
144 }
145 
146 static int usbtmc_release(struct inode *inode, struct file *file)
147 {
148 	struct usbtmc_device_data *data = file->private_data;
149 
150 	kref_put(&data->kref, usbtmc_delete);
151 	return 0;
152 }
153 
154 static int usbtmc_ioctl_abort_bulk_in(struct usbtmc_device_data *data)
155 {
156 	u8 *buffer;
157 	struct device *dev;
158 	int rv;
159 	int n;
160 	int actual;
161 	struct usb_host_interface *current_setting;
162 	int max_size;
163 
164 	dev = &data->intf->dev;
165 	buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
166 	if (!buffer)
167 		return -ENOMEM;
168 
169 	rv = usb_control_msg(data->usb_dev,
170 			     usb_rcvctrlpipe(data->usb_dev, 0),
171 			     USBTMC_REQUEST_INITIATE_ABORT_BULK_IN,
172 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
173 			     data->bTag_last_read, data->bulk_in,
174 			     buffer, 2, USBTMC_TIMEOUT);
175 
176 	if (rv < 0) {
177 		dev_err(dev, "usb_control_msg returned %d\n", rv);
178 		goto exit;
179 	}
180 
181 	dev_dbg(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
182 
183 	if (buffer[0] == USBTMC_STATUS_FAILED) {
184 		rv = 0;
185 		goto exit;
186 	}
187 
188 	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
189 		dev_err(dev, "INITIATE_ABORT_BULK_IN returned %x\n",
190 			buffer[0]);
191 		rv = -EPERM;
192 		goto exit;
193 	}
194 
195 	max_size = 0;
196 	current_setting = data->intf->cur_altsetting;
197 	for (n = 0; n < current_setting->desc.bNumEndpoints; n++)
198 		if (current_setting->endpoint[n].desc.bEndpointAddress ==
199 			data->bulk_in)
200 			max_size = usb_endpoint_maxp(&current_setting->endpoint[n].desc);
201 
202 	if (max_size == 0) {
203 		dev_err(dev, "Couldn't get wMaxPacketSize\n");
204 		rv = -EPERM;
205 		goto exit;
206 	}
207 
208 	dev_dbg(&data->intf->dev, "wMaxPacketSize is %d\n", max_size);
209 
210 	n = 0;
211 
212 	do {
213 		dev_dbg(dev, "Reading from bulk in EP\n");
214 
215 		rv = usb_bulk_msg(data->usb_dev,
216 				  usb_rcvbulkpipe(data->usb_dev,
217 						  data->bulk_in),
218 				  buffer, USBTMC_SIZE_IOBUFFER,
219 				  &actual, USBTMC_TIMEOUT);
220 
221 		n++;
222 
223 		if (rv < 0) {
224 			dev_err(dev, "usb_bulk_msg returned %d\n", rv);
225 			goto exit;
226 		}
227 	} while ((actual == max_size) &&
228 		 (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));
229 
230 	if (actual == max_size) {
231 		dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
232 			USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
233 		rv = -EPERM;
234 		goto exit;
235 	}
236 
237 	n = 0;
238 
239 usbtmc_abort_bulk_in_status:
240 	rv = usb_control_msg(data->usb_dev,
241 			     usb_rcvctrlpipe(data->usb_dev, 0),
242 			     USBTMC_REQUEST_CHECK_ABORT_BULK_IN_STATUS,
243 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
244 			     0, data->bulk_in, buffer, 0x08,
245 			     USBTMC_TIMEOUT);
246 
247 	if (rv < 0) {
248 		dev_err(dev, "usb_control_msg returned %d\n", rv);
249 		goto exit;
250 	}
251 
252 	dev_dbg(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
253 
254 	if (buffer[0] == USBTMC_STATUS_SUCCESS) {
255 		rv = 0;
256 		goto exit;
257 	}
258 
259 	if (buffer[0] != USBTMC_STATUS_PENDING) {
260 		dev_err(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
261 		rv = -EPERM;
262 		goto exit;
263 	}
264 
265 	if (buffer[1] == 1)
266 		do {
267 			dev_dbg(dev, "Reading from bulk in EP\n");
268 
269 			rv = usb_bulk_msg(data->usb_dev,
270 					  usb_rcvbulkpipe(data->usb_dev,
271 							  data->bulk_in),
272 					  buffer, USBTMC_SIZE_IOBUFFER,
273 					  &actual, USBTMC_TIMEOUT);
274 
275 			n++;
276 
277 			if (rv < 0) {
278 				dev_err(dev, "usb_bulk_msg returned %d\n", rv);
279 				goto exit;
280 			}
281 		} while ((actual == max_size) &&
282 			 (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));
283 
284 	if (actual == max_size) {
285 		dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
286 			USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
287 		rv = -EPERM;
288 		goto exit;
289 	}
290 
291 	goto usbtmc_abort_bulk_in_status;
292 
293 exit:
294 	kfree(buffer);
295 	return rv;
296 
297 }
298 
299 static int usbtmc_ioctl_abort_bulk_out(struct usbtmc_device_data *data)
300 {
301 	struct device *dev;
302 	u8 *buffer;
303 	int rv;
304 	int n;
305 
306 	dev = &data->intf->dev;
307 
308 	buffer = kmalloc(8, GFP_KERNEL);
309 	if (!buffer)
310 		return -ENOMEM;
311 
312 	rv = usb_control_msg(data->usb_dev,
313 			     usb_rcvctrlpipe(data->usb_dev, 0),
314 			     USBTMC_REQUEST_INITIATE_ABORT_BULK_OUT,
315 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
316 			     data->bTag_last_write, data->bulk_out,
317 			     buffer, 2, USBTMC_TIMEOUT);
318 
319 	if (rv < 0) {
320 		dev_err(dev, "usb_control_msg returned %d\n", rv);
321 		goto exit;
322 	}
323 
324 	dev_dbg(dev, "INITIATE_ABORT_BULK_OUT returned %x\n", buffer[0]);
325 
326 	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
327 		dev_err(dev, "INITIATE_ABORT_BULK_OUT returned %x\n",
328 			buffer[0]);
329 		rv = -EPERM;
330 		goto exit;
331 	}
332 
333 	n = 0;
334 
335 usbtmc_abort_bulk_out_check_status:
336 	rv = usb_control_msg(data->usb_dev,
337 			     usb_rcvctrlpipe(data->usb_dev, 0),
338 			     USBTMC_REQUEST_CHECK_ABORT_BULK_OUT_STATUS,
339 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
340 			     0, data->bulk_out, buffer, 0x08,
341 			     USBTMC_TIMEOUT);
342 	n++;
343 	if (rv < 0) {
344 		dev_err(dev, "usb_control_msg returned %d\n", rv);
345 		goto exit;
346 	}
347 
348 	dev_dbg(dev, "CHECK_ABORT_BULK_OUT returned %x\n", buffer[0]);
349 
350 	if (buffer[0] == USBTMC_STATUS_SUCCESS)
351 		goto usbtmc_abort_bulk_out_clear_halt;
352 
353 	if ((buffer[0] == USBTMC_STATUS_PENDING) &&
354 	    (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN))
355 		goto usbtmc_abort_bulk_out_check_status;
356 
357 	rv = -EPERM;
358 	goto exit;
359 
360 usbtmc_abort_bulk_out_clear_halt:
361 	rv = usb_clear_halt(data->usb_dev,
362 			    usb_sndbulkpipe(data->usb_dev, data->bulk_out));
363 
364 	if (rv < 0) {
365 		dev_err(dev, "usb_control_msg returned %d\n", rv);
366 		goto exit;
367 	}
368 	rv = 0;
369 
370 exit:
371 	kfree(buffer);
372 	return rv;
373 }
374 
375 /*
376  * Sends a REQUEST_DEV_DEP_MSG_IN message on the Bulk-IN endpoint.
377  * @transfer_size: number of bytes to request from the device.
378  *
379  * See the USBTMC specification, Table 4.
380  *
381  * Also updates bTag_last_write.
382  */
383 static int send_request_dev_dep_msg_in(struct usbtmc_device_data *data, size_t transfer_size)
384 {
385 	int retval;
386 	u8 *buffer;
387 	int actual;
388 
389 	buffer = kmalloc(USBTMC_HEADER_SIZE, GFP_KERNEL);
390 	if (!buffer)
391 		return -ENOMEM;
392 	/* Setup IO buffer for REQUEST_DEV_DEP_MSG_IN message
393 	 * Refer to class specs for details
394 	 */
395 	buffer[0] = 2;
396 	buffer[1] = data->bTag;
397 	buffer[2] = ~data->bTag;
398 	buffer[3] = 0; /* Reserved */
399 	buffer[4] = transfer_size >> 0;
400 	buffer[5] = transfer_size >> 8;
401 	buffer[6] = transfer_size >> 16;
402 	buffer[7] = transfer_size >> 24;
403 	buffer[8] = data->TermCharEnabled * 2;
404 	/* Use term character? */
405 	buffer[9] = data->TermChar;
406 	buffer[10] = 0; /* Reserved */
407 	buffer[11] = 0; /* Reserved */
408 
409 	/* Send bulk URB */
410 	retval = usb_bulk_msg(data->usb_dev,
411 			      usb_sndbulkpipe(data->usb_dev,
412 					      data->bulk_out),
413 			      buffer, USBTMC_HEADER_SIZE, &actual, USBTMC_TIMEOUT);
414 
415 	/* Store bTag (in case we need to abort) */
416 	data->bTag_last_write = data->bTag;
417 
418 	/* Increment bTag -- and increment again if zero */
419 	data->bTag++;
420 	if (!data->bTag)
421 		data->bTag++;
422 
423 	kfree(buffer);
424 	if (retval < 0) {
425 		dev_err(&data->intf->dev, "usb_bulk_msg in send_request_dev_dep_msg_in() returned %d\n", retval);
426 		return retval;
427 	}
428 
429 	return 0;
430 }
431 
432 static ssize_t usbtmc_read(struct file *filp, char __user *buf,
433 			   size_t count, loff_t *f_pos)
434 {
435 	struct usbtmc_device_data *data;
436 	struct device *dev;
437 	u32 n_characters;
438 	u8 *buffer;
439 	int actual;
440 	size_t done;
441 	size_t remaining;
442 	int retval;
443 	size_t this_part;
444 
445 	/* Get pointer to private data structure */
446 	data = filp->private_data;
447 	dev = &data->intf->dev;
448 
449 	buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
450 	if (!buffer)
451 		return -ENOMEM;
452 
453 	mutex_lock(&data->io_mutex);
454 	if (data->zombie) {
455 		retval = -ENODEV;
456 		goto exit;
457 	}
458 
459 	if (data->rigol_quirk) {
460 		dev_dbg(dev, "usb_bulk_msg_in: count(%zu)\n", count);
461 
462 		retval = send_request_dev_dep_msg_in(data, count);
463 
464 		if (retval < 0) {
465 			if (data->auto_abort)
466 				usbtmc_ioctl_abort_bulk_out(data);
467 			goto exit;
468 		}
469 	}
470 
471 	/* Loop until we have fetched everything we requested */
472 	remaining = count;
473 	this_part = remaining;
474 	done = 0;
475 
476 	while (remaining > 0) {
477 		if (!data->rigol_quirk) {
478 			dev_dbg(dev, "usb_bulk_msg_in: remaining(%zu), count(%zu)\n", remaining, count);
479 
480 			if (remaining > USBTMC_SIZE_IOBUFFER - USBTMC_HEADER_SIZE - 3)
481 				this_part = USBTMC_SIZE_IOBUFFER - USBTMC_HEADER_SIZE - 3;
482 			else
483 				this_part = remaining;
484 
485 			retval = send_request_dev_dep_msg_in(data, this_part);
486 			if (retval < 0) {
487 			dev_err(dev, "usb_bulk_msg returned %d\n", retval);
488 				if (data->auto_abort)
489 					usbtmc_ioctl_abort_bulk_out(data);
490 				goto exit;
491 			}
492 		}
493 
494 		/* Send bulk URB */
495 		retval = usb_bulk_msg(data->usb_dev,
496 				      usb_rcvbulkpipe(data->usb_dev,
497 						      data->bulk_in),
498 				      buffer, USBTMC_SIZE_IOBUFFER, &actual,
499 				      USBTMC_TIMEOUT);
500 
501 		dev_dbg(dev, "usb_bulk_msg: retval(%u), done(%zu), remaining(%zu), actual(%d)\n", retval, done, remaining, actual);
502 
503 		/* Store bTag (in case we need to abort) */
504 		data->bTag_last_read = data->bTag;
505 
506 		if (retval < 0) {
507 			dev_dbg(dev, "Unable to read data, error %d\n", retval);
508 			if (data->auto_abort)
509 				usbtmc_ioctl_abort_bulk_in(data);
510 			goto exit;
511 		}
512 
513 		/* Parse header in first packet */
514 		if ((done == 0) || !data->rigol_quirk) {
515 			/* Sanity checks for the header */
516 			if (actual < USBTMC_HEADER_SIZE) {
517 				dev_err(dev, "Device sent too small first packet: %u < %u\n", actual, USBTMC_HEADER_SIZE);
518 				if (data->auto_abort)
519 					usbtmc_ioctl_abort_bulk_in(data);
520 				goto exit;
521 			}
522 
523 			if (buffer[0] != 2) {
524 				dev_err(dev, "Device sent reply with wrong MsgID: %u != 2\n", buffer[0]);
525 				if (data->auto_abort)
526 					usbtmc_ioctl_abort_bulk_in(data);
527 				goto exit;
528 			}
529 
530 			if (buffer[1] != data->bTag_last_write) {
531 				dev_err(dev, "Device sent reply with wrong bTag: %u != %u\n", buffer[1], data->bTag_last_write);
532 				if (data->auto_abort)
533 					usbtmc_ioctl_abort_bulk_in(data);
534 				goto exit;
535 			}
536 
537 			/* How many characters did the instrument send? */
538 			n_characters = buffer[4] +
539 				       (buffer[5] << 8) +
540 				       (buffer[6] << 16) +
541 				       (buffer[7] << 24);
542 
543 			if (n_characters > this_part) {
544 				dev_err(dev, "Device wants to return more data than requested: %u > %zu\n", n_characters, count);
545 				if (data->auto_abort)
546 					usbtmc_ioctl_abort_bulk_in(data);
547 				goto exit;
548 			}
549 
550 			/* Remove the USBTMC header */
551 			actual -= USBTMC_HEADER_SIZE;
552 
553 			/* Check if the message is smaller than requested */
554 			if (data->rigol_quirk) {
555 				if (remaining > n_characters)
556 					remaining = n_characters;
557 				/* Remove padding if it exists */
558 				if (actual > remaining)
559 					actual = remaining;
560 			}
561 			else {
562 				if (this_part > n_characters)
563 					this_part = n_characters;
564 				/* Remove padding if it exists */
565 				if (actual > this_part)
566 					actual = this_part;
567 			}
568 
569 			dev_dbg(dev, "Bulk-IN header: N_characters(%u), bTransAttr(%u)\n", n_characters, buffer[8]);
570 
571 			remaining -= actual;
572 
573 			/* Terminate if end-of-message bit received from device */
574 			if ((buffer[8] & 0x01) && (actual >= n_characters))
575 				remaining = 0;
576 
577 			dev_dbg(dev, "Bulk-IN header: remaining(%zu), buf(%p), buffer(%p) done(%zu)\n", remaining,buf,buffer,done);
578 
579 
580 			/* Copy buffer to user space */
581 			if (copy_to_user(buf + done, &buffer[USBTMC_HEADER_SIZE], actual)) {
582 				/* There must have been an addressing problem */
583 				retval = -EFAULT;
584 				goto exit;
585 			}
586 			done += actual;
587 		}
588 		else  {
589 			if (actual > remaining)
590 				actual = remaining;
591 
592 			remaining -= actual;
593 
594 			dev_dbg(dev, "Bulk-IN header cont: actual(%u), done(%zu), remaining(%zu), buf(%p), buffer(%p)\n", actual, done, remaining,buf,buffer);
595 
596 			/* Copy buffer to user space */
597 			if (copy_to_user(buf + done, buffer, actual)) {
598 				/* There must have been an addressing problem */
599 				retval = -EFAULT;
600 				goto exit;
601 			}
602 			done += actual;
603 		}
604 	}
605 
606 	/* Update file position value */
607 	*f_pos = *f_pos + done;
608 	retval = done;
609 
610 exit:
611 	mutex_unlock(&data->io_mutex);
612 	kfree(buffer);
613 	return retval;
614 }
615 
616 static ssize_t usbtmc_write(struct file *filp, const char __user *buf,
617 			    size_t count, loff_t *f_pos)
618 {
619 	struct usbtmc_device_data *data;
620 	u8 *buffer;
621 	int retval;
622 	int actual;
623 	unsigned long int n_bytes;
624 	int remaining;
625 	int done;
626 	int this_part;
627 
628 	data = filp->private_data;
629 
630 	buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
631 	if (!buffer)
632 		return -ENOMEM;
633 
634 	mutex_lock(&data->io_mutex);
635 	if (data->zombie) {
636 		retval = -ENODEV;
637 		goto exit;
638 	}
639 
640 	remaining = count;
641 	done = 0;
642 
643 	while (remaining > 0) {
644 		if (remaining > USBTMC_SIZE_IOBUFFER - USBTMC_HEADER_SIZE) {
645 			this_part = USBTMC_SIZE_IOBUFFER - USBTMC_HEADER_SIZE;
646 			buffer[8] = 0;
647 		} else {
648 			this_part = remaining;
649 			buffer[8] = 1;
650 		}
651 
652 		/* Setup IO buffer for DEV_DEP_MSG_OUT message */
653 		buffer[0] = 1;
654 		buffer[1] = data->bTag;
655 		buffer[2] = ~data->bTag;
656 		buffer[3] = 0; /* Reserved */
657 		buffer[4] = this_part >> 0;
658 		buffer[5] = this_part >> 8;
659 		buffer[6] = this_part >> 16;
660 		buffer[7] = this_part >> 24;
661 		/* buffer[8] is set above... */
662 		buffer[9] = 0; /* Reserved */
663 		buffer[10] = 0; /* Reserved */
664 		buffer[11] = 0; /* Reserved */
665 
666 		if (copy_from_user(&buffer[USBTMC_HEADER_SIZE], buf + done, this_part)) {
667 			retval = -EFAULT;
668 			goto exit;
669 		}
670 
671 		n_bytes = roundup(USBTMC_HEADER_SIZE + this_part, 4);
672 		memset(buffer + USBTMC_HEADER_SIZE + this_part, 0, n_bytes - (USBTMC_HEADER_SIZE + this_part));
673 
674 		do {
675 			retval = usb_bulk_msg(data->usb_dev,
676 					      usb_sndbulkpipe(data->usb_dev,
677 							      data->bulk_out),
678 					      buffer, n_bytes,
679 					      &actual, USBTMC_TIMEOUT);
680 			if (retval != 0)
681 				break;
682 			n_bytes -= actual;
683 		} while (n_bytes);
684 
685 		data->bTag_last_write = data->bTag;
686 		data->bTag++;
687 
688 		if (!data->bTag)
689 			data->bTag++;
690 
691 		if (retval < 0) {
692 			dev_err(&data->intf->dev,
693 				"Unable to send data, error %d\n", retval);
694 			if (data->auto_abort)
695 				usbtmc_ioctl_abort_bulk_out(data);
696 			goto exit;
697 		}
698 
699 		remaining -= this_part;
700 		done += this_part;
701 	}
702 
703 	retval = count;
704 exit:
705 	mutex_unlock(&data->io_mutex);
706 	kfree(buffer);
707 	return retval;
708 }
709 
710 static int usbtmc_ioctl_clear(struct usbtmc_device_data *data)
711 {
712 	struct usb_host_interface *current_setting;
713 	struct usb_endpoint_descriptor *desc;
714 	struct device *dev;
715 	u8 *buffer;
716 	int rv;
717 	int n;
718 	int actual = 0;
719 	int max_size;
720 
721 	dev = &data->intf->dev;
722 
723 	dev_dbg(dev, "Sending INITIATE_CLEAR request\n");
724 
725 	buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
726 	if (!buffer)
727 		return -ENOMEM;
728 
729 	rv = usb_control_msg(data->usb_dev,
730 			     usb_rcvctrlpipe(data->usb_dev, 0),
731 			     USBTMC_REQUEST_INITIATE_CLEAR,
732 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
733 			     0, 0, buffer, 1, USBTMC_TIMEOUT);
734 	if (rv < 0) {
735 		dev_err(dev, "usb_control_msg returned %d\n", rv);
736 		goto exit;
737 	}
738 
739 	dev_dbg(dev, "INITIATE_CLEAR returned %x\n", buffer[0]);
740 
741 	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
742 		dev_err(dev, "INITIATE_CLEAR returned %x\n", buffer[0]);
743 		rv = -EPERM;
744 		goto exit;
745 	}
746 
747 	max_size = 0;
748 	current_setting = data->intf->cur_altsetting;
749 	for (n = 0; n < current_setting->desc.bNumEndpoints; n++) {
750 		desc = &current_setting->endpoint[n].desc;
751 		if (desc->bEndpointAddress == data->bulk_in)
752 			max_size = usb_endpoint_maxp(desc);
753 	}
754 
755 	if (max_size == 0) {
756 		dev_err(dev, "Couldn't get wMaxPacketSize\n");
757 		rv = -EPERM;
758 		goto exit;
759 	}
760 
761 	dev_dbg(dev, "wMaxPacketSize is %d\n", max_size);
762 
763 	n = 0;
764 
765 usbtmc_clear_check_status:
766 
767 	dev_dbg(dev, "Sending CHECK_CLEAR_STATUS request\n");
768 
769 	rv = usb_control_msg(data->usb_dev,
770 			     usb_rcvctrlpipe(data->usb_dev, 0),
771 			     USBTMC_REQUEST_CHECK_CLEAR_STATUS,
772 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
773 			     0, 0, buffer, 2, USBTMC_TIMEOUT);
774 	if (rv < 0) {
775 		dev_err(dev, "usb_control_msg returned %d\n", rv);
776 		goto exit;
777 	}
778 
779 	dev_dbg(dev, "CHECK_CLEAR_STATUS returned %x\n", buffer[0]);
780 
781 	if (buffer[0] == USBTMC_STATUS_SUCCESS)
782 		goto usbtmc_clear_bulk_out_halt;
783 
784 	if (buffer[0] != USBTMC_STATUS_PENDING) {
785 		dev_err(dev, "CHECK_CLEAR_STATUS returned %x\n", buffer[0]);
786 		rv = -EPERM;
787 		goto exit;
788 	}
789 
790 	if (buffer[1] == 1)
791 		do {
792 			dev_dbg(dev, "Reading from bulk in EP\n");
793 
794 			rv = usb_bulk_msg(data->usb_dev,
795 					  usb_rcvbulkpipe(data->usb_dev,
796 							  data->bulk_in),
797 					  buffer, USBTMC_SIZE_IOBUFFER,
798 					  &actual, USBTMC_TIMEOUT);
799 			n++;
800 
801 			if (rv < 0) {
802 				dev_err(dev, "usb_control_msg returned %d\n",
803 					rv);
804 				goto exit;
805 			}
806 		} while ((actual == max_size) &&
807 			  (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));
808 
809 	if (actual == max_size) {
810 		dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
811 			USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
812 		rv = -EPERM;
813 		goto exit;
814 	}
815 
816 	goto usbtmc_clear_check_status;
817 
818 usbtmc_clear_bulk_out_halt:
819 
820 	rv = usb_clear_halt(data->usb_dev,
821 			    usb_sndbulkpipe(data->usb_dev, data->bulk_out));
822 	if (rv < 0) {
823 		dev_err(dev, "usb_control_msg returned %d\n", rv);
824 		goto exit;
825 	}
826 	rv = 0;
827 
828 exit:
829 	kfree(buffer);
830 	return rv;
831 }
832 
833 static int usbtmc_ioctl_clear_out_halt(struct usbtmc_device_data *data)
834 {
835 	int rv;
836 
837 	rv = usb_clear_halt(data->usb_dev,
838 			    usb_sndbulkpipe(data->usb_dev, data->bulk_out));
839 
840 	if (rv < 0) {
841 		dev_err(&data->usb_dev->dev, "usb_control_msg returned %d\n",
842 			rv);
843 		return rv;
844 	}
845 	return 0;
846 }
847 
848 static int usbtmc_ioctl_clear_in_halt(struct usbtmc_device_data *data)
849 {
850 	int rv;
851 
852 	rv = usb_clear_halt(data->usb_dev,
853 			    usb_rcvbulkpipe(data->usb_dev, data->bulk_in));
854 
855 	if (rv < 0) {
856 		dev_err(&data->usb_dev->dev, "usb_control_msg returned %d\n",
857 			rv);
858 		return rv;
859 	}
860 	return 0;
861 }
862 
863 static int get_capabilities(struct usbtmc_device_data *data)
864 {
865 	struct device *dev = &data->usb_dev->dev;
866 	char *buffer;
867 	int rv = 0;
868 
869 	buffer = kmalloc(0x18, GFP_KERNEL);
870 	if (!buffer)
871 		return -ENOMEM;
872 
873 	rv = usb_control_msg(data->usb_dev, usb_rcvctrlpipe(data->usb_dev, 0),
874 			     USBTMC_REQUEST_GET_CAPABILITIES,
875 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
876 			     0, 0, buffer, 0x18, USBTMC_TIMEOUT);
877 	if (rv < 0) {
878 		dev_err(dev, "usb_control_msg returned %d\n", rv);
879 		goto err_out;
880 	}
881 
882 	dev_dbg(dev, "GET_CAPABILITIES returned %x\n", buffer[0]);
883 	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
884 		dev_err(dev, "GET_CAPABILITIES returned %x\n", buffer[0]);
885 		rv = -EPERM;
886 		goto err_out;
887 	}
888 	dev_dbg(dev, "Interface capabilities are %x\n", buffer[4]);
889 	dev_dbg(dev, "Device capabilities are %x\n", buffer[5]);
890 	dev_dbg(dev, "USB488 interface capabilities are %x\n", buffer[14]);
891 	dev_dbg(dev, "USB488 device capabilities are %x\n", buffer[15]);
892 
893 	data->capabilities.interface_capabilities = buffer[4];
894 	data->capabilities.device_capabilities = buffer[5];
895 	data->capabilities.usb488_interface_capabilities = buffer[14];
896 	data->capabilities.usb488_device_capabilities = buffer[15];
897 	rv = 0;
898 
899 err_out:
900 	kfree(buffer);
901 	return rv;
902 }
903 
904 #define capability_attribute(name)					\
905 static ssize_t name##_show(struct device *dev,				\
906 			   struct device_attribute *attr, char *buf)	\
907 {									\
908 	struct usb_interface *intf = to_usb_interface(dev);		\
909 	struct usbtmc_device_data *data = usb_get_intfdata(intf);	\
910 									\
911 	return sprintf(buf, "%d\n", data->capabilities.name);		\
912 }									\
913 static DEVICE_ATTR_RO(name)
914 
915 capability_attribute(interface_capabilities);
916 capability_attribute(device_capabilities);
917 capability_attribute(usb488_interface_capabilities);
918 capability_attribute(usb488_device_capabilities);
919 
920 static struct attribute *capability_attrs[] = {
921 	&dev_attr_interface_capabilities.attr,
922 	&dev_attr_device_capabilities.attr,
923 	&dev_attr_usb488_interface_capabilities.attr,
924 	&dev_attr_usb488_device_capabilities.attr,
925 	NULL,
926 };
927 
928 static struct attribute_group capability_attr_grp = {
929 	.attrs = capability_attrs,
930 };
931 
932 static ssize_t TermChar_show(struct device *dev,
933 			     struct device_attribute *attr, char *buf)
934 {
935 	struct usb_interface *intf = to_usb_interface(dev);
936 	struct usbtmc_device_data *data = usb_get_intfdata(intf);
937 
938 	return sprintf(buf, "%c\n", data->TermChar);
939 }
940 
941 static ssize_t TermChar_store(struct device *dev,
942 			      struct device_attribute *attr,
943 			      const char *buf, size_t count)
944 {
945 	struct usb_interface *intf = to_usb_interface(dev);
946 	struct usbtmc_device_data *data = usb_get_intfdata(intf);
947 
948 	if (count < 1)
949 		return -EINVAL;
950 	data->TermChar = buf[0];
951 	return count;
952 }
953 static DEVICE_ATTR_RW(TermChar);
954 
955 #define data_attribute(name)						\
956 static ssize_t name##_show(struct device *dev,				\
957 			   struct device_attribute *attr, char *buf)	\
958 {									\
959 	struct usb_interface *intf = to_usb_interface(dev);		\
960 	struct usbtmc_device_data *data = usb_get_intfdata(intf);	\
961 									\
962 	return sprintf(buf, "%d\n", data->name);			\
963 }									\
964 static ssize_t name##_store(struct device *dev,				\
965 			    struct device_attribute *attr,		\
966 			    const char *buf, size_t count)		\
967 {									\
968 	struct usb_interface *intf = to_usb_interface(dev);		\
969 	struct usbtmc_device_data *data = usb_get_intfdata(intf);	\
970 	ssize_t result;							\
971 	unsigned val;							\
972 									\
973 	result = sscanf(buf, "%u\n", &val);				\
974 	if (result != 1)						\
975 		result = -EINVAL;					\
976 	data->name = val;						\
977 	if (result < 0)							\
978 		return result;						\
979 	else								\
980 		return count;						\
981 }									\
982 static DEVICE_ATTR_RW(name)
983 
984 data_attribute(TermCharEnabled);
985 data_attribute(auto_abort);
986 
987 static struct attribute *data_attrs[] = {
988 	&dev_attr_TermChar.attr,
989 	&dev_attr_TermCharEnabled.attr,
990 	&dev_attr_auto_abort.attr,
991 	NULL,
992 };
993 
994 static struct attribute_group data_attr_grp = {
995 	.attrs = data_attrs,
996 };
997 
998 static int usbtmc_ioctl_indicator_pulse(struct usbtmc_device_data *data)
999 {
1000 	struct device *dev;
1001 	u8 *buffer;
1002 	int rv;
1003 
1004 	dev = &data->intf->dev;
1005 
1006 	buffer = kmalloc(2, GFP_KERNEL);
1007 	if (!buffer)
1008 		return -ENOMEM;
1009 
1010 	rv = usb_control_msg(data->usb_dev,
1011 			     usb_rcvctrlpipe(data->usb_dev, 0),
1012 			     USBTMC_REQUEST_INDICATOR_PULSE,
1013 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
1014 			     0, 0, buffer, 0x01, USBTMC_TIMEOUT);
1015 
1016 	if (rv < 0) {
1017 		dev_err(dev, "usb_control_msg returned %d\n", rv);
1018 		goto exit;
1019 	}
1020 
1021 	dev_dbg(dev, "INDICATOR_PULSE returned %x\n", buffer[0]);
1022 
1023 	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
1024 		dev_err(dev, "INDICATOR_PULSE returned %x\n", buffer[0]);
1025 		rv = -EPERM;
1026 		goto exit;
1027 	}
1028 	rv = 0;
1029 
1030 exit:
1031 	kfree(buffer);
1032 	return rv;
1033 }
1034 
1035 static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1036 {
1037 	struct usbtmc_device_data *data;
1038 	int retval = -EBADRQC;
1039 
1040 	data = file->private_data;
1041 	mutex_lock(&data->io_mutex);
1042 	if (data->zombie) {
1043 		retval = -ENODEV;
1044 		goto skip_io_on_zombie;
1045 	}
1046 
1047 	switch (cmd) {
1048 	case USBTMC_IOCTL_CLEAR_OUT_HALT:
1049 		retval = usbtmc_ioctl_clear_out_halt(data);
1050 		break;
1051 
1052 	case USBTMC_IOCTL_CLEAR_IN_HALT:
1053 		retval = usbtmc_ioctl_clear_in_halt(data);
1054 		break;
1055 
1056 	case USBTMC_IOCTL_INDICATOR_PULSE:
1057 		retval = usbtmc_ioctl_indicator_pulse(data);
1058 		break;
1059 
1060 	case USBTMC_IOCTL_CLEAR:
1061 		retval = usbtmc_ioctl_clear(data);
1062 		break;
1063 
1064 	case USBTMC_IOCTL_ABORT_BULK_OUT:
1065 		retval = usbtmc_ioctl_abort_bulk_out(data);
1066 		break;
1067 
1068 	case USBTMC_IOCTL_ABORT_BULK_IN:
1069 		retval = usbtmc_ioctl_abort_bulk_in(data);
1070 		break;
1071 	}
1072 
1073 skip_io_on_zombie:
1074 	mutex_unlock(&data->io_mutex);
1075 	return retval;
1076 }
1077 
1078 static const struct file_operations fops = {
1079 	.owner		= THIS_MODULE,
1080 	.read		= usbtmc_read,
1081 	.write		= usbtmc_write,
1082 	.open		= usbtmc_open,
1083 	.release	= usbtmc_release,
1084 	.unlocked_ioctl	= usbtmc_ioctl,
1085 	.llseek		= default_llseek,
1086 };
1087 
1088 static struct usb_class_driver usbtmc_class = {
1089 	.name =		"usbtmc%d",
1090 	.fops =		&fops,
1091 	.minor_base =	USBTMC_MINOR_BASE,
1092 };
1093 
1094 
1095 static int usbtmc_probe(struct usb_interface *intf,
1096 			const struct usb_device_id *id)
1097 {
1098 	struct usbtmc_device_data *data;
1099 	struct usb_host_interface *iface_desc;
1100 	struct usb_endpoint_descriptor *endpoint;
1101 	int n;
1102 	int retcode;
1103 
1104 	dev_dbg(&intf->dev, "%s called\n", __func__);
1105 
1106 	data = devm_kzalloc(&intf->dev, sizeof(*data), GFP_KERNEL);
1107 	if (!data)
1108 		return -ENOMEM;
1109 
1110 	data->intf = intf;
1111 	data->id = id;
1112 	data->usb_dev = usb_get_dev(interface_to_usbdev(intf));
1113 	usb_set_intfdata(intf, data);
1114 	kref_init(&data->kref);
1115 	mutex_init(&data->io_mutex);
1116 	data->zombie = 0;
1117 
1118 	/* Determine if it is a Rigol or not */
1119 	data->rigol_quirk = 0;
1120 	dev_dbg(&intf->dev, "Trying to find if device Vendor 0x%04X Product 0x%04X has the RIGOL quirk\n",
1121 		le16_to_cpu(data->usb_dev->descriptor.idVendor),
1122 		le16_to_cpu(data->usb_dev->descriptor.idProduct));
1123 	for(n = 0; usbtmc_id_quirk[n].idVendor > 0; n++) {
1124 		if ((usbtmc_id_quirk[n].idVendor == le16_to_cpu(data->usb_dev->descriptor.idVendor)) &&
1125 		    (usbtmc_id_quirk[n].idProduct == le16_to_cpu(data->usb_dev->descriptor.idProduct))) {
1126 			dev_dbg(&intf->dev, "Setting this device as having the RIGOL quirk\n");
1127 			data->rigol_quirk = 1;
1128 			break;
1129 		}
1130 	}
1131 
1132 	/* Initialize USBTMC bTag and other fields */
1133 	data->bTag	= 1;
1134 	data->TermCharEnabled = 0;
1135 	data->TermChar = '\n';
1136 
1137 	/* USBTMC devices have only one setting, so use that */
1138 	iface_desc = data->intf->cur_altsetting;
1139 
1140 	/* Find bulk in endpoint */
1141 	for (n = 0; n < iface_desc->desc.bNumEndpoints; n++) {
1142 		endpoint = &iface_desc->endpoint[n].desc;
1143 
1144 		if (usb_endpoint_is_bulk_in(endpoint)) {
1145 			data->bulk_in = endpoint->bEndpointAddress;
1146 			dev_dbg(&intf->dev, "Found bulk in endpoint at %u\n",
1147 				data->bulk_in);
1148 			break;
1149 		}
1150 	}
1151 
1152 	/* Find bulk out endpoint */
1153 	for (n = 0; n < iface_desc->desc.bNumEndpoints; n++) {
1154 		endpoint = &iface_desc->endpoint[n].desc;
1155 
1156 		if (usb_endpoint_is_bulk_out(endpoint)) {
1157 			data->bulk_out = endpoint->bEndpointAddress;
1158 			dev_dbg(&intf->dev, "Found Bulk out endpoint at %u\n",
1159 				data->bulk_out);
1160 			break;
1161 		}
1162 	}
1163 
1164 	retcode = get_capabilities(data);
1165 	if (retcode)
1166 		dev_err(&intf->dev, "can't read capabilities\n");
1167 	else
1168 		retcode = sysfs_create_group(&intf->dev.kobj,
1169 					     &capability_attr_grp);
1170 
1171 	retcode = sysfs_create_group(&intf->dev.kobj, &data_attr_grp);
1172 
1173 	retcode = usb_register_dev(intf, &usbtmc_class);
1174 	if (retcode) {
1175 		dev_err(&intf->dev, "Not able to get a minor"
1176 			" (base %u, slice default): %d\n", USBTMC_MINOR_BASE,
1177 			retcode);
1178 		goto error_register;
1179 	}
1180 	dev_dbg(&intf->dev, "Using minor number %d\n", intf->minor);
1181 
1182 	return 0;
1183 
1184 error_register:
1185 	sysfs_remove_group(&intf->dev.kobj, &capability_attr_grp);
1186 	sysfs_remove_group(&intf->dev.kobj, &data_attr_grp);
1187 	kref_put(&data->kref, usbtmc_delete);
1188 	return retcode;
1189 }
1190 
1191 static void usbtmc_disconnect(struct usb_interface *intf)
1192 {
1193 	struct usbtmc_device_data *data;
1194 
1195 	dev_dbg(&intf->dev, "usbtmc_disconnect called\n");
1196 
1197 	data = usb_get_intfdata(intf);
1198 	usb_deregister_dev(intf, &usbtmc_class);
1199 	sysfs_remove_group(&intf->dev.kobj, &capability_attr_grp);
1200 	sysfs_remove_group(&intf->dev.kobj, &data_attr_grp);
1201 	mutex_lock(&data->io_mutex);
1202 	data->zombie = 1;
1203 	mutex_unlock(&data->io_mutex);
1204 	kref_put(&data->kref, usbtmc_delete);
1205 }
1206 
1207 static int usbtmc_suspend(struct usb_interface *intf, pm_message_t message)
1208 {
1209 	/* this driver does not have pending URBs */
1210 	return 0;
1211 }
1212 
1213 static int usbtmc_resume(struct usb_interface *intf)
1214 {
1215 	return 0;
1216 }
1217 
1218 static struct usb_driver usbtmc_driver = {
1219 	.name		= "usbtmc",
1220 	.id_table	= usbtmc_devices,
1221 	.probe		= usbtmc_probe,
1222 	.disconnect	= usbtmc_disconnect,
1223 	.suspend	= usbtmc_suspend,
1224 	.resume		= usbtmc_resume,
1225 };
1226 
1227 module_usb_driver(usbtmc_driver);
1228 
1229 MODULE_LICENSE("GPL");
1230