xref: /openbmc/linux/drivers/usb/class/usbtmc.c (revision 80ecbd24)
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 #include <linux/init.h>
23 #include <linux/module.h>
24 #include <linux/kernel.h>
25 #include <linux/fs.h>
26 #include <linux/uaccess.h>
27 #include <linux/kref.h>
28 #include <linux/slab.h>
29 #include <linux/mutex.h>
30 #include <linux/usb.h>
31 #include <linux/usb/tmc.h>
32 
33 
34 #define RIGOL			1
35 #define USBTMC_HEADER_SIZE	12
36 #define USBTMC_MINOR_BASE	176
37 
38 /*
39  * Size of driver internal IO buffer. Must be multiple of 4 and at least as
40  * large as wMaxPacketSize (which is usually 512 bytes).
41  */
42 #define USBTMC_SIZE_IOBUFFER	2048
43 
44 /* Default USB timeout (in milliseconds) */
45 #define USBTMC_TIMEOUT		5000
46 
47 /*
48  * Maximum number of read cycles to empty bulk in endpoint during CLEAR and
49  * ABORT_BULK_IN requests. Ends the loop if (for whatever reason) a short
50  * packet is never read.
51  */
52 #define USBTMC_MAX_READS_TO_CLEAR_BULK_IN	100
53 
54 static const struct usb_device_id usbtmc_devices[] = {
55 	{ USB_INTERFACE_INFO(USB_CLASS_APP_SPEC, 3, 0), },
56 	{ USB_INTERFACE_INFO(USB_CLASS_APP_SPEC, 3, 1), },
57 	{ 0, } /* terminating entry */
58 };
59 MODULE_DEVICE_TABLE(usb, usbtmc_devices);
60 
61 /*
62  * This structure is the capabilities for the device
63  * See section 4.2.1.8 of the USBTMC specification,
64  * and section 4.2.2 of the USBTMC usb488 subclass
65  * specification for details.
66  */
67 struct usbtmc_dev_capabilities {
68 	__u8 interface_capabilities;
69 	__u8 device_capabilities;
70 	__u8 usb488_interface_capabilities;
71 	__u8 usb488_device_capabilities;
72 };
73 
74 /* This structure holds private data for each USBTMC device. One copy is
75  * allocated for each USBTMC device in the driver's probe function.
76  */
77 struct usbtmc_device_data {
78 	const struct usb_device_id *id;
79 	struct usb_device *usb_dev;
80 	struct usb_interface *intf;
81 
82 	unsigned int bulk_in;
83 	unsigned int bulk_out;
84 
85 	u8 bTag;
86 	u8 bTag_last_write;	/* needed for abort */
87 	u8 bTag_last_read;	/* needed for abort */
88 
89 	u8 rigol_quirk;
90 
91 	/* attributes from the USB TMC spec for this device */
92 	u8 TermChar;
93 	bool TermCharEnabled;
94 	bool auto_abort;
95 
96 	bool zombie; /* fd of disconnected device */
97 
98 	struct usbtmc_dev_capabilities	capabilities;
99 	struct kref kref;
100 	struct mutex io_mutex;	/* only one i/o function running at a time */
101 };
102 #define to_usbtmc_data(d) container_of(d, struct usbtmc_device_data, kref)
103 
104 struct usbtmc_ID_rigol_quirk {
105 	__u16 idVendor;
106 	__u16 idProduct;
107 };
108 
109 static const struct usbtmc_ID_rigol_quirk usbtmc_id_quirk[] = {
110 	{ 0x1ab1, 0x0588 },
111 	{ 0, 0 }
112 };
113 
114 /* Forward declarations */
115 static struct usb_driver usbtmc_driver;
116 
117 static void usbtmc_delete(struct kref *kref)
118 {
119 	struct usbtmc_device_data *data = to_usbtmc_data(kref);
120 
121 	usb_put_dev(data->usb_dev);
122 	kfree(data);
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 		printk(KERN_ERR KBUILD_MODNAME
134 		       ": can not find device for minor %d", iminor(inode));
135 		retval = -ENODEV;
136 		goto exit;
137 	}
138 
139 	data = usb_get_intfdata(intf);
140 	kref_get(&data->kref);
141 
142 	/* Store pointer in file structure's private data field */
143 	filp->private_data = data;
144 
145 exit:
146 	return retval;
147 }
148 
149 static int usbtmc_release(struct inode *inode, struct file *file)
150 {
151 	struct usbtmc_device_data *data = file->private_data;
152 
153 	kref_put(&data->kref, usbtmc_delete);
154 	return 0;
155 }
156 
157 static int usbtmc_ioctl_abort_bulk_in(struct usbtmc_device_data *data)
158 {
159 	u8 *buffer;
160 	struct device *dev;
161 	int rv;
162 	int n;
163 	int actual;
164 	struct usb_host_interface *current_setting;
165 	int max_size;
166 
167 	dev = &data->intf->dev;
168 	buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
169 	if (!buffer)
170 		return -ENOMEM;
171 
172 	rv = usb_control_msg(data->usb_dev,
173 			     usb_rcvctrlpipe(data->usb_dev, 0),
174 			     USBTMC_REQUEST_INITIATE_ABORT_BULK_IN,
175 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
176 			     data->bTag_last_read, data->bulk_in,
177 			     buffer, 2, USBTMC_TIMEOUT);
178 
179 	if (rv < 0) {
180 		dev_err(dev, "usb_control_msg returned %d\n", rv);
181 		goto exit;
182 	}
183 
184 	dev_dbg(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
185 
186 	if (buffer[0] == USBTMC_STATUS_FAILED) {
187 		rv = 0;
188 		goto exit;
189 	}
190 
191 	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
192 		dev_err(dev, "INITIATE_ABORT_BULK_IN returned %x\n",
193 			buffer[0]);
194 		rv = -EPERM;
195 		goto exit;
196 	}
197 
198 	max_size = 0;
199 	current_setting = data->intf->cur_altsetting;
200 	for (n = 0; n < current_setting->desc.bNumEndpoints; n++)
201 		if (current_setting->endpoint[n].desc.bEndpointAddress ==
202 			data->bulk_in)
203 			max_size = usb_endpoint_maxp(&current_setting->endpoint[n].desc);
204 
205 	if (max_size == 0) {
206 		dev_err(dev, "Couldn't get wMaxPacketSize\n");
207 		rv = -EPERM;
208 		goto exit;
209 	}
210 
211 	dev_dbg(&data->intf->dev, "wMaxPacketSize is %d\n", max_size);
212 
213 	n = 0;
214 
215 	do {
216 		dev_dbg(dev, "Reading from bulk in EP\n");
217 
218 		rv = usb_bulk_msg(data->usb_dev,
219 				  usb_rcvbulkpipe(data->usb_dev,
220 						  data->bulk_in),
221 				  buffer, USBTMC_SIZE_IOBUFFER,
222 				  &actual, USBTMC_TIMEOUT);
223 
224 		n++;
225 
226 		if (rv < 0) {
227 			dev_err(dev, "usb_bulk_msg returned %d\n", rv);
228 			goto exit;
229 		}
230 	} while ((actual == max_size) &&
231 		 (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));
232 
233 	if (actual == max_size) {
234 		dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
235 			USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
236 		rv = -EPERM;
237 		goto exit;
238 	}
239 
240 	n = 0;
241 
242 usbtmc_abort_bulk_in_status:
243 	rv = usb_control_msg(data->usb_dev,
244 			     usb_rcvctrlpipe(data->usb_dev, 0),
245 			     USBTMC_REQUEST_CHECK_ABORT_BULK_IN_STATUS,
246 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
247 			     0, data->bulk_in, buffer, 0x08,
248 			     USBTMC_TIMEOUT);
249 
250 	if (rv < 0) {
251 		dev_err(dev, "usb_control_msg returned %d\n", rv);
252 		goto exit;
253 	}
254 
255 	dev_dbg(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
256 
257 	if (buffer[0] == USBTMC_STATUS_SUCCESS) {
258 		rv = 0;
259 		goto exit;
260 	}
261 
262 	if (buffer[0] != USBTMC_STATUS_PENDING) {
263 		dev_err(dev, "INITIATE_ABORT_BULK_IN returned %x\n", buffer[0]);
264 		rv = -EPERM;
265 		goto exit;
266 	}
267 
268 	if (buffer[1] == 1)
269 		do {
270 			dev_dbg(dev, "Reading from bulk in EP\n");
271 
272 			rv = usb_bulk_msg(data->usb_dev,
273 					  usb_rcvbulkpipe(data->usb_dev,
274 							  data->bulk_in),
275 					  buffer, USBTMC_SIZE_IOBUFFER,
276 					  &actual, USBTMC_TIMEOUT);
277 
278 			n++;
279 
280 			if (rv < 0) {
281 				dev_err(dev, "usb_bulk_msg returned %d\n", rv);
282 				goto exit;
283 			}
284 		} while ((actual == max_size) &&
285 			 (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));
286 
287 	if (actual == max_size) {
288 		dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
289 			USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
290 		rv = -EPERM;
291 		goto exit;
292 	}
293 
294 	goto usbtmc_abort_bulk_in_status;
295 
296 exit:
297 	kfree(buffer);
298 	return rv;
299 
300 }
301 
302 static int usbtmc_ioctl_abort_bulk_out(struct usbtmc_device_data *data)
303 {
304 	struct device *dev;
305 	u8 *buffer;
306 	int rv;
307 	int n;
308 
309 	dev = &data->intf->dev;
310 
311 	buffer = kmalloc(8, GFP_KERNEL);
312 	if (!buffer)
313 		return -ENOMEM;
314 
315 	rv = usb_control_msg(data->usb_dev,
316 			     usb_rcvctrlpipe(data->usb_dev, 0),
317 			     USBTMC_REQUEST_INITIATE_ABORT_BULK_OUT,
318 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
319 			     data->bTag_last_write, data->bulk_out,
320 			     buffer, 2, USBTMC_TIMEOUT);
321 
322 	if (rv < 0) {
323 		dev_err(dev, "usb_control_msg returned %d\n", rv);
324 		goto exit;
325 	}
326 
327 	dev_dbg(dev, "INITIATE_ABORT_BULK_OUT returned %x\n", buffer[0]);
328 
329 	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
330 		dev_err(dev, "INITIATE_ABORT_BULK_OUT returned %x\n",
331 			buffer[0]);
332 		rv = -EPERM;
333 		goto exit;
334 	}
335 
336 	n = 0;
337 
338 usbtmc_abort_bulk_out_check_status:
339 	rv = usb_control_msg(data->usb_dev,
340 			     usb_rcvctrlpipe(data->usb_dev, 0),
341 			     USBTMC_REQUEST_CHECK_ABORT_BULK_OUT_STATUS,
342 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_ENDPOINT,
343 			     0, data->bulk_out, buffer, 0x08,
344 			     USBTMC_TIMEOUT);
345 	n++;
346 	if (rv < 0) {
347 		dev_err(dev, "usb_control_msg returned %d\n", rv);
348 		goto exit;
349 	}
350 
351 	dev_dbg(dev, "CHECK_ABORT_BULK_OUT returned %x\n", buffer[0]);
352 
353 	if (buffer[0] == USBTMC_STATUS_SUCCESS)
354 		goto usbtmc_abort_bulk_out_clear_halt;
355 
356 	if ((buffer[0] == USBTMC_STATUS_PENDING) &&
357 	    (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN))
358 		goto usbtmc_abort_bulk_out_check_status;
359 
360 	rv = -EPERM;
361 	goto exit;
362 
363 usbtmc_abort_bulk_out_clear_halt:
364 	rv = usb_clear_halt(data->usb_dev,
365 			    usb_sndbulkpipe(data->usb_dev, data->bulk_out));
366 
367 	if (rv < 0) {
368 		dev_err(dev, "usb_control_msg returned %d\n", rv);
369 		goto exit;
370 	}
371 	rv = 0;
372 
373 exit:
374 	kfree(buffer);
375 	return rv;
376 }
377 
378 /*
379  * Sends a REQUEST_DEV_DEP_MSG_IN message on the Bulk-IN endpoint.
380  * @transfer_size: number of bytes to request from the device.
381  *
382  * See the USBTMC specification, Table 4.
383  *
384  * Also updates bTag_last_write.
385  */
386 static int send_request_dev_dep_msg_in(struct usbtmc_device_data *data, size_t transfer_size)
387 {
388 	int retval;
389 	u8 buffer[USBTMC_HEADER_SIZE];
390 	int actual;
391 
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) & 255;
400 	buffer[5] = ((transfer_size) >> 8) & 255;
401 	buffer[6] = ((transfer_size) >> 16) & 255;
402 	buffer[7] = ((transfer_size) >> 24) & 255;
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 	if (retval < 0) {
424 		dev_err(&data->intf->dev, "usb_bulk_msg in send_request_dev_dep_msg_in() returned %d\n", retval);
425 		return retval;
426 	}
427 
428 	return 0;
429 }
430 
431 static ssize_t usbtmc_read(struct file *filp, char __user *buf,
432 			   size_t count, loff_t *f_pos)
433 {
434 	struct usbtmc_device_data *data;
435 	struct device *dev;
436 	u32 n_characters;
437 	u8 *buffer;
438 	int actual;
439 	size_t done;
440 	size_t remaining;
441 	int retval;
442 	size_t this_part;
443 
444 	/* Get pointer to private data structure */
445 	data = filp->private_data;
446 	dev = &data->intf->dev;
447 
448 	buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
449 	if (!buffer)
450 		return -ENOMEM;
451 
452 	mutex_lock(&data->io_mutex);
453 	if (data->zombie) {
454 		retval = -ENODEV;
455 		goto exit;
456 	}
457 
458 	if (data->rigol_quirk) {
459 		dev_dbg(dev, "usb_bulk_msg_in: count(%zu)\n", count);
460 
461 		retval = send_request_dev_dep_msg_in(data, count);
462 
463 		if (retval < 0) {
464 			if (data->auto_abort)
465 				usbtmc_ioctl_abort_bulk_out(data);
466 			goto exit;
467 		}
468 	}
469 
470 	/* Loop until we have fetched everything we requested */
471 	remaining = count;
472 	this_part = remaining;
473 	done = 0;
474 
475 	while (remaining > 0) {
476 		if (!(data->rigol_quirk)) {
477 			dev_dbg(dev, "usb_bulk_msg_in: remaining(%zu), count(%zu)\n", remaining, count);
478 
479 			if (remaining > USBTMC_SIZE_IOBUFFER - USBTMC_HEADER_SIZE - 3)
480 				this_part = USBTMC_SIZE_IOBUFFER - USBTMC_HEADER_SIZE - 3;
481 			else
482 				this_part = remaining;
483 
484 			retval = send_request_dev_dep_msg_in(data, this_part);
485 			if (retval < 0) {
486 			dev_err(dev, "usb_bulk_msg returned %d\n", retval);
487 				if (data->auto_abort)
488 					usbtmc_ioctl_abort_bulk_out(data);
489 				goto exit;
490 			}
491 		}
492 
493 		/* Send bulk URB */
494 		retval = usb_bulk_msg(data->usb_dev,
495 				      usb_rcvbulkpipe(data->usb_dev,
496 						      data->bulk_in),
497 				      buffer, USBTMC_SIZE_IOBUFFER, &actual,
498 				      USBTMC_TIMEOUT);
499 
500 		dev_dbg(dev, "usb_bulk_msg: retval(%u), done(%zu), remaining(%zu), actual(%d)\n", retval, done, remaining, actual);
501 
502 		/* Store bTag (in case we need to abort) */
503 		data->bTag_last_read = data->bTag;
504 
505 		if (retval < 0) {
506 			dev_dbg(dev, "Unable to read data, error %d\n", retval);
507 			if (data->auto_abort)
508 				usbtmc_ioctl_abort_bulk_in(data);
509 			goto exit;
510 		}
511 
512 		/* Parse header in first packet */
513 		if ((done == 0) || (!(data->rigol_quirk))) {
514 			/* Sanity checks for the header */
515 			if (actual < USBTMC_HEADER_SIZE) {
516 				dev_err(dev, "Device sent too small first packet: %u < %u\n", actual, USBTMC_HEADER_SIZE);
517 				if (data->auto_abort)
518 					usbtmc_ioctl_abort_bulk_in(data);
519 				goto exit;
520 			}
521 
522 			if (buffer[0] != 2) {
523 				dev_err(dev, "Device sent reply with wrong MsgID: %u != 2\n", buffer[0]);
524 				if (data->auto_abort)
525 					usbtmc_ioctl_abort_bulk_in(data);
526 				goto exit;
527 			}
528 
529 			if (buffer[1] != data->bTag_last_write) {
530 				dev_err(dev, "Device sent reply with wrong bTag: %u != %u\n", buffer[1], data->bTag_last_write);
531 				if (data->auto_abort)
532 					usbtmc_ioctl_abort_bulk_in(data);
533 				goto exit;
534 			}
535 
536 			/* How many characters did the instrument send? */
537 			n_characters = buffer[4] +
538 				       (buffer[5] << 8) +
539 				       (buffer[6] << 16) +
540 				       (buffer[7] << 24);
541 
542 			if (n_characters > this_part) {
543 				dev_err(dev, "Device wants to return more data than requested: %u > %zu\n", n_characters, count);
544 				if (data->auto_abort)
545 					usbtmc_ioctl_abort_bulk_in(data);
546 				goto exit;
547 			}
548 
549 			/* Remove the USBTMC header */
550 			actual -= USBTMC_HEADER_SIZE;
551 
552 			/* Check if the message is smaller than requested */
553 			if (data->rigol_quirk) {
554 				if (remaining > n_characters)
555 					remaining = n_characters;
556 				/* Remove padding if it exists */
557 				if (actual > remaining)
558 					actual = remaining;
559 			}
560 			else {
561 				if (this_part > n_characters)
562 					this_part = n_characters;
563 				/* Remove padding if it exists */
564 				if (actual > this_part)
565 					actual = this_part;
566 			}
567 
568 			dev_dbg(dev, "Bulk-IN header: N_characters(%u), bTransAttr(%u)\n", n_characters, buffer[8]);
569 
570 			remaining -= actual;
571 
572 			/* Terminate if end-of-message bit received from device */
573 			if ((buffer[8] &  0x01) && (actual >= n_characters))
574 				remaining = 0;
575 
576 			dev_dbg(dev, "Bulk-IN header: remaining(%zu), buf(%p), buffer(%p) done(%zu)\n", remaining,buf,buffer,done);
577 
578 
579 			/* Copy buffer to user space */
580 			if (copy_to_user(buf + done, &buffer[USBTMC_HEADER_SIZE], actual)) {
581 				/* There must have been an addressing problem */
582 				retval = -EFAULT;
583 				goto exit;
584 			}
585 			done += actual;
586 		}
587 		else  {
588 			if (actual > remaining)
589 				actual = remaining;
590 
591 			remaining -= actual;
592 
593 			dev_dbg(dev, "Bulk-IN header cont: actual(%u), done(%zu), remaining(%zu), buf(%p), buffer(%p)\n", actual, done, remaining,buf,buffer);
594 
595 			/* Copy buffer to user space */
596 			if (copy_to_user(buf + done, buffer, actual)) {
597 				/* There must have been an addressing problem */
598 				retval = -EFAULT;
599 				goto exit;
600 			}
601 			done += actual;
602 		}
603 	}
604 
605 	/* Update file position value */
606 	*f_pos = *f_pos + done;
607 	retval = done;
608 
609 exit:
610 	mutex_unlock(&data->io_mutex);
611 	kfree(buffer);
612 	return retval;
613 }
614 
615 static ssize_t usbtmc_write(struct file *filp, const char __user *buf,
616 			    size_t count, loff_t *f_pos)
617 {
618 	struct usbtmc_device_data *data;
619 	u8 *buffer;
620 	int retval;
621 	int actual;
622 	unsigned long int n_bytes;
623 	int remaining;
624 	int done;
625 	int this_part;
626 
627 	data = filp->private_data;
628 
629 	buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
630 	if (!buffer)
631 		return -ENOMEM;
632 
633 	mutex_lock(&data->io_mutex);
634 	if (data->zombie) {
635 		retval = -ENODEV;
636 		goto exit;
637 	}
638 
639 	remaining = count;
640 	done = 0;
641 
642 	while (remaining > 0) {
643 		if (remaining > USBTMC_SIZE_IOBUFFER - USBTMC_HEADER_SIZE) {
644 			this_part = USBTMC_SIZE_IOBUFFER - USBTMC_HEADER_SIZE;
645 			buffer[8] = 0;
646 		} else {
647 			this_part = remaining;
648 			buffer[8] = 1;
649 		}
650 
651 		/* Setup IO buffer for DEV_DEP_MSG_OUT message */
652 		buffer[0] = 1;
653 		buffer[1] = data->bTag;
654 		buffer[2] = ~(data->bTag);
655 		buffer[3] = 0; /* Reserved */
656 		buffer[4] = this_part & 255;
657 		buffer[5] = (this_part >> 8) & 255;
658 		buffer[6] = (this_part >> 16) & 255;
659 		buffer[7] = (this_part >> 24) & 255;
660 		/* buffer[8] is set above... */
661 		buffer[9] = 0; /* Reserved */
662 		buffer[10] = 0; /* Reserved */
663 		buffer[11] = 0; /* Reserved */
664 
665 		if (copy_from_user(&buffer[USBTMC_HEADER_SIZE], buf + done, this_part)) {
666 			retval = -EFAULT;
667 			goto exit;
668 		}
669 
670 		n_bytes = roundup(USBTMC_HEADER_SIZE + this_part, 4);
671 		memset(buffer + USBTMC_HEADER_SIZE + this_part, 0, n_bytes - (USBTMC_HEADER_SIZE + this_part));
672 
673 		do {
674 			retval = usb_bulk_msg(data->usb_dev,
675 					      usb_sndbulkpipe(data->usb_dev,
676 							      data->bulk_out),
677 					      buffer, n_bytes,
678 					      &actual, USBTMC_TIMEOUT);
679 			if (retval != 0)
680 				break;
681 			n_bytes -= actual;
682 		} while (n_bytes);
683 
684 		data->bTag_last_write = data->bTag;
685 		data->bTag++;
686 
687 		if (!data->bTag)
688 			data->bTag++;
689 
690 		if (retval < 0) {
691 			dev_err(&data->intf->dev,
692 				"Unable to send data, error %d\n", retval);
693 			if (data->auto_abort)
694 				usbtmc_ioctl_abort_bulk_out(data);
695 			goto exit;
696 		}
697 
698 		remaining -= this_part;
699 		done += this_part;
700 	}
701 
702 	retval = count;
703 exit:
704 	mutex_unlock(&data->io_mutex);
705 	kfree(buffer);
706 	return retval;
707 }
708 
709 static int usbtmc_ioctl_clear(struct usbtmc_device_data *data)
710 {
711 	struct usb_host_interface *current_setting;
712 	struct usb_endpoint_descriptor *desc;
713 	struct device *dev;
714 	u8 *buffer;
715 	int rv;
716 	int n;
717 	int actual;
718 	int max_size;
719 
720 	dev = &data->intf->dev;
721 
722 	dev_dbg(dev, "Sending INITIATE_CLEAR request\n");
723 
724 	buffer = kmalloc(USBTMC_SIZE_IOBUFFER, GFP_KERNEL);
725 	if (!buffer)
726 		return -ENOMEM;
727 
728 	rv = usb_control_msg(data->usb_dev,
729 			     usb_rcvctrlpipe(data->usb_dev, 0),
730 			     USBTMC_REQUEST_INITIATE_CLEAR,
731 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
732 			     0, 0, buffer, 1, USBTMC_TIMEOUT);
733 	if (rv < 0) {
734 		dev_err(dev, "usb_control_msg returned %d\n", rv);
735 		goto exit;
736 	}
737 
738 	dev_dbg(dev, "INITIATE_CLEAR returned %x\n", buffer[0]);
739 
740 	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
741 		dev_err(dev, "INITIATE_CLEAR returned %x\n", buffer[0]);
742 		rv = -EPERM;
743 		goto exit;
744 	}
745 
746 	max_size = 0;
747 	current_setting = data->intf->cur_altsetting;
748 	for (n = 0; n < current_setting->desc.bNumEndpoints; n++) {
749 		desc = &current_setting->endpoint[n].desc;
750 		if (desc->bEndpointAddress == data->bulk_in)
751 			max_size = usb_endpoint_maxp(desc);
752 	}
753 
754 	if (max_size == 0) {
755 		dev_err(dev, "Couldn't get wMaxPacketSize\n");
756 		rv = -EPERM;
757 		goto exit;
758 	}
759 
760 	dev_dbg(dev, "wMaxPacketSize is %d\n", max_size);
761 
762 	n = 0;
763 
764 usbtmc_clear_check_status:
765 
766 	dev_dbg(dev, "Sending CHECK_CLEAR_STATUS request\n");
767 
768 	rv = usb_control_msg(data->usb_dev,
769 			     usb_rcvctrlpipe(data->usb_dev, 0),
770 			     USBTMC_REQUEST_CHECK_CLEAR_STATUS,
771 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
772 			     0, 0, buffer, 2, USBTMC_TIMEOUT);
773 	if (rv < 0) {
774 		dev_err(dev, "usb_control_msg returned %d\n", rv);
775 		goto exit;
776 	}
777 
778 	dev_dbg(dev, "CHECK_CLEAR_STATUS returned %x\n", buffer[0]);
779 
780 	if (buffer[0] == USBTMC_STATUS_SUCCESS)
781 		goto usbtmc_clear_bulk_out_halt;
782 
783 	if (buffer[0] != USBTMC_STATUS_PENDING) {
784 		dev_err(dev, "CHECK_CLEAR_STATUS returned %x\n", buffer[0]);
785 		rv = -EPERM;
786 		goto exit;
787 	}
788 
789 	if (buffer[1] == 1)
790 		do {
791 			dev_dbg(dev, "Reading from bulk in EP\n");
792 
793 			rv = usb_bulk_msg(data->usb_dev,
794 					  usb_rcvbulkpipe(data->usb_dev,
795 							  data->bulk_in),
796 					  buffer, USBTMC_SIZE_IOBUFFER,
797 					  &actual, USBTMC_TIMEOUT);
798 			n++;
799 
800 			if (rv < 0) {
801 				dev_err(dev, "usb_control_msg returned %d\n",
802 					rv);
803 				goto exit;
804 			}
805 		} while ((actual == max_size) &&
806 			  (n < USBTMC_MAX_READS_TO_CLEAR_BULK_IN));
807 
808 	if (actual == max_size) {
809 		dev_err(dev, "Couldn't clear device buffer within %d cycles\n",
810 			USBTMC_MAX_READS_TO_CLEAR_BULK_IN);
811 		rv = -EPERM;
812 		goto exit;
813 	}
814 
815 	goto usbtmc_clear_check_status;
816 
817 usbtmc_clear_bulk_out_halt:
818 
819 	rv = usb_clear_halt(data->usb_dev,
820 			    usb_sndbulkpipe(data->usb_dev, data->bulk_out));
821 	if (rv < 0) {
822 		dev_err(dev, "usb_control_msg returned %d\n", rv);
823 		goto exit;
824 	}
825 	rv = 0;
826 
827 exit:
828 	kfree(buffer);
829 	return rv;
830 }
831 
832 static int usbtmc_ioctl_clear_out_halt(struct usbtmc_device_data *data)
833 {
834 	int rv;
835 
836 	rv = usb_clear_halt(data->usb_dev,
837 			    usb_sndbulkpipe(data->usb_dev, data->bulk_out));
838 
839 	if (rv < 0) {
840 		dev_err(&data->usb_dev->dev, "usb_control_msg returned %d\n",
841 			rv);
842 		return rv;
843 	}
844 	return 0;
845 }
846 
847 static int usbtmc_ioctl_clear_in_halt(struct usbtmc_device_data *data)
848 {
849 	int rv;
850 
851 	rv = usb_clear_halt(data->usb_dev,
852 			    usb_rcvbulkpipe(data->usb_dev, data->bulk_in));
853 
854 	if (rv < 0) {
855 		dev_err(&data->usb_dev->dev, "usb_control_msg returned %d\n",
856 			rv);
857 		return rv;
858 	}
859 	return 0;
860 }
861 
862 static int get_capabilities(struct usbtmc_device_data *data)
863 {
864 	struct device *dev = &data->usb_dev->dev;
865 	char *buffer;
866 	int rv = 0;
867 
868 	buffer = kmalloc(0x18, GFP_KERNEL);
869 	if (!buffer)
870 		return -ENOMEM;
871 
872 	rv = usb_control_msg(data->usb_dev, usb_rcvctrlpipe(data->usb_dev, 0),
873 			     USBTMC_REQUEST_GET_CAPABILITIES,
874 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
875 			     0, 0, buffer, 0x18, USBTMC_TIMEOUT);
876 	if (rv < 0) {
877 		dev_err(dev, "usb_control_msg returned %d\n", rv);
878 		goto err_out;
879 	}
880 
881 	dev_dbg(dev, "GET_CAPABILITIES returned %x\n", buffer[0]);
882 	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
883 		dev_err(dev, "GET_CAPABILITIES returned %x\n", buffer[0]);
884 		rv = -EPERM;
885 		goto err_out;
886 	}
887 	dev_dbg(dev, "Interface capabilities are %x\n", buffer[4]);
888 	dev_dbg(dev, "Device capabilities are %x\n", buffer[5]);
889 	dev_dbg(dev, "USB488 interface capabilities are %x\n", buffer[14]);
890 	dev_dbg(dev, "USB488 device capabilities are %x\n", buffer[15]);
891 
892 	data->capabilities.interface_capabilities = buffer[4];
893 	data->capabilities.device_capabilities = buffer[5];
894 	data->capabilities.usb488_interface_capabilities = buffer[14];
895 	data->capabilities.usb488_device_capabilities = buffer[15];
896 	rv = 0;
897 
898 err_out:
899 	kfree(buffer);
900 	return rv;
901 }
902 
903 #define capability_attribute(name)					\
904 static ssize_t show_##name(struct device *dev,				\
905 			   struct device_attribute *attr, char *buf)	\
906 {									\
907 	struct usb_interface *intf = to_usb_interface(dev);		\
908 	struct usbtmc_device_data *data = usb_get_intfdata(intf);	\
909 									\
910 	return sprintf(buf, "%d\n", data->capabilities.name);		\
911 }									\
912 static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
913 
914 capability_attribute(interface_capabilities);
915 capability_attribute(device_capabilities);
916 capability_attribute(usb488_interface_capabilities);
917 capability_attribute(usb488_device_capabilities);
918 
919 static struct attribute *capability_attrs[] = {
920 	&dev_attr_interface_capabilities.attr,
921 	&dev_attr_device_capabilities.attr,
922 	&dev_attr_usb488_interface_capabilities.attr,
923 	&dev_attr_usb488_device_capabilities.attr,
924 	NULL,
925 };
926 
927 static struct attribute_group capability_attr_grp = {
928 	.attrs = capability_attrs,
929 };
930 
931 static ssize_t show_TermChar(struct device *dev,
932 			     struct device_attribute *attr, char *buf)
933 {
934 	struct usb_interface *intf = to_usb_interface(dev);
935 	struct usbtmc_device_data *data = usb_get_intfdata(intf);
936 
937 	return sprintf(buf, "%c\n", data->TermChar);
938 }
939 
940 static ssize_t store_TermChar(struct device *dev,
941 			      struct device_attribute *attr,
942 			      const char *buf, size_t count)
943 {
944 	struct usb_interface *intf = to_usb_interface(dev);
945 	struct usbtmc_device_data *data = usb_get_intfdata(intf);
946 
947 	if (count < 1)
948 		return -EINVAL;
949 	data->TermChar = buf[0];
950 	return count;
951 }
952 static DEVICE_ATTR(TermChar, S_IRUGO, show_TermChar, store_TermChar);
953 
954 #define data_attribute(name)						\
955 static ssize_t show_##name(struct device *dev,				\
956 			   struct device_attribute *attr, char *buf)	\
957 {									\
958 	struct usb_interface *intf = to_usb_interface(dev);		\
959 	struct usbtmc_device_data *data = usb_get_intfdata(intf);	\
960 									\
961 	return sprintf(buf, "%d\n", data->name);			\
962 }									\
963 static ssize_t store_##name(struct device *dev,				\
964 			    struct device_attribute *attr,		\
965 			    const char *buf, size_t count)		\
966 {									\
967 	struct usb_interface *intf = to_usb_interface(dev);		\
968 	struct usbtmc_device_data *data = usb_get_intfdata(intf);	\
969 	ssize_t result;							\
970 	unsigned val;							\
971 									\
972 	result = sscanf(buf, "%u\n", &val);				\
973 	if (result != 1)						\
974 		result = -EINVAL;					\
975 	data->name = val;						\
976 	if (result < 0)							\
977 		return result;						\
978 	else								\
979 		return count;						\
980 }									\
981 static DEVICE_ATTR(name, S_IRUGO, show_##name, store_##name)
982 
983 data_attribute(TermCharEnabled);
984 data_attribute(auto_abort);
985 
986 static struct attribute *data_attrs[] = {
987 	&dev_attr_TermChar.attr,
988 	&dev_attr_TermCharEnabled.attr,
989 	&dev_attr_auto_abort.attr,
990 	NULL,
991 };
992 
993 static struct attribute_group data_attr_grp = {
994 	.attrs = data_attrs,
995 };
996 
997 static int usbtmc_ioctl_indicator_pulse(struct usbtmc_device_data *data)
998 {
999 	struct device *dev;
1000 	u8 *buffer;
1001 	int rv;
1002 
1003 	dev = &data->intf->dev;
1004 
1005 	buffer = kmalloc(2, GFP_KERNEL);
1006 	if (!buffer)
1007 		return -ENOMEM;
1008 
1009 	rv = usb_control_msg(data->usb_dev,
1010 			     usb_rcvctrlpipe(data->usb_dev, 0),
1011 			     USBTMC_REQUEST_INDICATOR_PULSE,
1012 			     USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
1013 			     0, 0, buffer, 0x01, USBTMC_TIMEOUT);
1014 
1015 	if (rv < 0) {
1016 		dev_err(dev, "usb_control_msg returned %d\n", rv);
1017 		goto exit;
1018 	}
1019 
1020 	dev_dbg(dev, "INDICATOR_PULSE returned %x\n", buffer[0]);
1021 
1022 	if (buffer[0] != USBTMC_STATUS_SUCCESS) {
1023 		dev_err(dev, "INDICATOR_PULSE returned %x\n", buffer[0]);
1024 		rv = -EPERM;
1025 		goto exit;
1026 	}
1027 	rv = 0;
1028 
1029 exit:
1030 	kfree(buffer);
1031 	return rv;
1032 }
1033 
1034 static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
1035 {
1036 	struct usbtmc_device_data *data;
1037 	int retval = -EBADRQC;
1038 
1039 	data = file->private_data;
1040 	mutex_lock(&data->io_mutex);
1041 	if (data->zombie) {
1042 		retval = -ENODEV;
1043 		goto skip_io_on_zombie;
1044 	}
1045 
1046 	switch (cmd) {
1047 	case USBTMC_IOCTL_CLEAR_OUT_HALT:
1048 		retval = usbtmc_ioctl_clear_out_halt(data);
1049 		break;
1050 
1051 	case USBTMC_IOCTL_CLEAR_IN_HALT:
1052 		retval = usbtmc_ioctl_clear_in_halt(data);
1053 		break;
1054 
1055 	case USBTMC_IOCTL_INDICATOR_PULSE:
1056 		retval = usbtmc_ioctl_indicator_pulse(data);
1057 		break;
1058 
1059 	case USBTMC_IOCTL_CLEAR:
1060 		retval = usbtmc_ioctl_clear(data);
1061 		break;
1062 
1063 	case USBTMC_IOCTL_ABORT_BULK_OUT:
1064 		retval = usbtmc_ioctl_abort_bulk_out(data);
1065 		break;
1066 
1067 	case USBTMC_IOCTL_ABORT_BULK_IN:
1068 		retval = usbtmc_ioctl_abort_bulk_in(data);
1069 		break;
1070 	}
1071 
1072 skip_io_on_zombie:
1073 	mutex_unlock(&data->io_mutex);
1074 	return retval;
1075 }
1076 
1077 static const struct file_operations fops = {
1078 	.owner		= THIS_MODULE,
1079 	.read		= usbtmc_read,
1080 	.write		= usbtmc_write,
1081 	.open		= usbtmc_open,
1082 	.release	= usbtmc_release,
1083 	.unlocked_ioctl	= usbtmc_ioctl,
1084 	.llseek		= default_llseek,
1085 };
1086 
1087 static struct usb_class_driver usbtmc_class = {
1088 	.name =		"usbtmc%d",
1089 	.fops =		&fops,
1090 	.minor_base =	USBTMC_MINOR_BASE,
1091 };
1092 
1093 
1094 static int usbtmc_probe(struct usb_interface *intf,
1095 			const struct usb_device_id *id)
1096 {
1097 	struct usbtmc_device_data *data;
1098 	struct usb_host_interface *iface_desc;
1099 	struct usb_endpoint_descriptor *endpoint;
1100 	int n;
1101 	int retcode;
1102 
1103 	dev_dbg(&intf->dev, "%s called\n", __func__);
1104 
1105 	data = kmalloc(sizeof(struct usbtmc_device_data), GFP_KERNEL);
1106 	if (!data) {
1107 		dev_err(&intf->dev, "Unable to allocate kernel memory\n");
1108 		return -ENOMEM;
1109 	}
1110 
1111 	data->intf = intf;
1112 	data->id = id;
1113 	data->usb_dev = usb_get_dev(interface_to_usbdev(intf));
1114 	usb_set_intfdata(intf, data);
1115 	kref_init(&data->kref);
1116 	mutex_init(&data->io_mutex);
1117 	data->zombie = 0;
1118 
1119 	/* Determine if it is a Rigol or not */
1120 	data->rigol_quirk = 0;
1121 	dev_dbg(&intf->dev, "Trying to find if device Vendor 0x%04X Product 0x%04X has the RIGOL quirk\n",
1122 		le16_to_cpu(data->usb_dev->descriptor.idVendor),
1123 		le16_to_cpu(data->usb_dev->descriptor.idProduct));
1124 	for(n = 0; usbtmc_id_quirk[n].idVendor > 0; n++) {
1125 		if ((usbtmc_id_quirk[n].idVendor == le16_to_cpu(data->usb_dev->descriptor.idVendor)) &&
1126 		    (usbtmc_id_quirk[n].idProduct == le16_to_cpu(data->usb_dev->descriptor.idProduct))) {
1127 			dev_dbg(&intf->dev, "Setting this device as having the RIGOL quirk\n");
1128 			data->rigol_quirk = 1;
1129 			break;
1130 		}
1131 	}
1132 
1133 	/* Initialize USBTMC bTag and other fields */
1134 	data->bTag	= 1;
1135 	data->TermCharEnabled = 0;
1136 	data->TermChar = '\n';
1137 
1138 	/* USBTMC devices have only one setting, so use that */
1139 	iface_desc = data->intf->cur_altsetting;
1140 
1141 	/* Find bulk in endpoint */
1142 	for (n = 0; n < iface_desc->desc.bNumEndpoints; n++) {
1143 		endpoint = &iface_desc->endpoint[n].desc;
1144 
1145 		if (usb_endpoint_is_bulk_in(endpoint)) {
1146 			data->bulk_in = endpoint->bEndpointAddress;
1147 			dev_dbg(&intf->dev, "Found bulk in endpoint at %u\n",
1148 				data->bulk_in);
1149 			break;
1150 		}
1151 	}
1152 
1153 	/* Find bulk out endpoint */
1154 	for (n = 0; n < iface_desc->desc.bNumEndpoints; n++) {
1155 		endpoint = &iface_desc->endpoint[n].desc;
1156 
1157 		if (usb_endpoint_is_bulk_out(endpoint)) {
1158 			data->bulk_out = endpoint->bEndpointAddress;
1159 			dev_dbg(&intf->dev, "Found Bulk out endpoint at %u\n",
1160 				data->bulk_out);
1161 			break;
1162 		}
1163 	}
1164 
1165 	retcode = get_capabilities(data);
1166 	if (retcode)
1167 		dev_err(&intf->dev, "can't read capabilities\n");
1168 	else
1169 		retcode = sysfs_create_group(&intf->dev.kobj,
1170 					     &capability_attr_grp);
1171 
1172 	retcode = sysfs_create_group(&intf->dev.kobj, &data_attr_grp);
1173 
1174 	retcode = usb_register_dev(intf, &usbtmc_class);
1175 	if (retcode) {
1176 		dev_err(&intf->dev, "Not able to get a minor"
1177 			" (base %u, slice default): %d\n", USBTMC_MINOR_BASE,
1178 			retcode);
1179 		goto error_register;
1180 	}
1181 	dev_dbg(&intf->dev, "Using minor number %d\n", intf->minor);
1182 
1183 	return 0;
1184 
1185 error_register:
1186 	sysfs_remove_group(&intf->dev.kobj, &capability_attr_grp);
1187 	sysfs_remove_group(&intf->dev.kobj, &data_attr_grp);
1188 	kref_put(&data->kref, usbtmc_delete);
1189 	return retcode;
1190 }
1191 
1192 static void usbtmc_disconnect(struct usb_interface *intf)
1193 {
1194 	struct usbtmc_device_data *data;
1195 
1196 	dev_dbg(&intf->dev, "usbtmc_disconnect called\n");
1197 
1198 	data = usb_get_intfdata(intf);
1199 	usb_deregister_dev(intf, &usbtmc_class);
1200 	sysfs_remove_group(&intf->dev.kobj, &capability_attr_grp);
1201 	sysfs_remove_group(&intf->dev.kobj, &data_attr_grp);
1202 	mutex_lock(&data->io_mutex);
1203 	data->zombie = 1;
1204 	mutex_unlock(&data->io_mutex);
1205 	kref_put(&data->kref, usbtmc_delete);
1206 }
1207 
1208 static int usbtmc_suspend(struct usb_interface *intf, pm_message_t message)
1209 {
1210 	/* this driver does not have pending URBs */
1211 	return 0;
1212 }
1213 
1214 static int usbtmc_resume(struct usb_interface *intf)
1215 {
1216 	return 0;
1217 }
1218 
1219 static struct usb_driver usbtmc_driver = {
1220 	.name		= "usbtmc",
1221 	.id_table	= usbtmc_devices,
1222 	.probe		= usbtmc_probe,
1223 	.disconnect	= usbtmc_disconnect,
1224 	.suspend	= usbtmc_suspend,
1225 	.resume		= usbtmc_resume,
1226 };
1227 
1228 module_usb_driver(usbtmc_driver);
1229 
1230 MODULE_LICENSE("GPL");
1231