aboutsummaryrefslogtreecommitdiff
path: root/drivers/usb/serial/generic.c
blob: 83443d6306d60e03f5b60ea0f9c4b70ae01f292b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
/*
 * USB Serial Converter Generic functions
 *
 * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License version
 *	2 as published by the Free Software Foundation.
 *
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <linux/uaccess.h>
#include <linux/kfifo.h>

static int debug;

#ifdef CONFIG_USB_SERIAL_GENERIC

static int generic_probe(struct usb_interface *interface,
			 const struct usb_device_id *id);

static __u16 vendor  = 0x05f9;
static __u16 product = 0xffff;

module_param(vendor, ushort, 0);
MODULE_PARM_DESC(vendor, "User specified USB idVendor");

module_param(product, ushort, 0);
MODULE_PARM_DESC(product, "User specified USB idProduct");

static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */

/* we want to look at all devices, as the vendor/product id can change
 * depending on the command line argument */
static struct usb_device_id generic_serial_ids[] = {
	{.driver_info = 42},
	{}
};

static struct usb_driver generic_driver = {
	.name =		"usbserial_generic",
	.probe =	generic_probe,
	.disconnect =	usb_serial_disconnect,
	.id_table =	generic_serial_ids,
	.no_dynamic_id =	1,
};

/* All of the device info needed for the Generic Serial Converter */
struct usb_serial_driver usb_serial_generic_device = {
	.driver = {
		.owner =	THIS_MODULE,
		.name =		"generic",
	},
	.id_table =		generic_device_ids,
	.usb_driver = 		&generic_driver,
	.num_ports =		1,
	.disconnect =		usb_serial_generic_disconnect,
	.release =		usb_serial_generic_release,
	.throttle =		usb_serial_generic_throttle,
	.unthrottle =		usb_serial_generic_unthrottle,
	.resume =		usb_serial_generic_resume,
};

static int generic_probe(struct usb_interface *interface,
			       const struct usb_device_id *id)
{
	const struct usb_device_id *id_pattern;

	id_pattern = usb_match_id(interface, generic_device_ids);
	if (id_pattern != NULL)
		return usb_serial_probe(interface, id);
	return -ENODEV;
}
#endif

int usb_serial_generic_register(int _debug)
{
	int retval = 0;

	debug = _debug;
#ifdef CONFIG_USB_SERIAL_GENERIC
	generic_device_ids[0].idVendor = vendor;
	generic_device_ids[0].idProduct = product;
	generic_device_ids[0].match_flags =
		USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;

	/* register our generic driver with ourselves */
	retval = usb_serial_register(&usb_serial_generic_device);
	if (retval)
		goto exit;
	retval = usb_register(&generic_driver);
	if (retval)
		usb_serial_deregister(&usb_serial_generic_device);
exit:
#endif
	return retval;
}

void usb_serial_generic_deregister(void)
{
#ifdef CONFIG_USB_SERIAL_GENERIC
	/* remove our generic driver */
	usb_deregister(&generic_driver);
	usb_serial_deregister(&usb_serial_generic_device);
#endif
}

int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
{
	struct usb_serial *serial = port->serial;
	int result = 0;
	unsigned long flags;

	dbg("%s - port %d", __func__, port->number);

	/* clear the throttle flags */
	spin_lock_irqsave(&port->lock, flags);
	port->throttled = 0;
	port->throttle_req = 0;
	spin_unlock_irqrestore(&port->lock, flags);

	/* if we have a bulk endpoint, start reading from it */
	if (serial->num_bulk_in) {
		/* Start reading from the device */
		usb_fill_bulk_urb(port->read_urb, serial->dev,
				   usb_rcvbulkpipe(serial->dev,
						port->bulk_in_endpointAddress),
				   port->read_urb->transfer_buffer,
				   port->read_urb->transfer_buffer_length,
				   ((serial->type->read_bulk_callback) ?
				     serial->type->read_bulk_callback :
				     usb_serial_generic_read_bulk_callback),
				   port);
		result = usb_submit_urb(port->read_urb, GFP_KERNEL);
		if (result)
			dev_err(&port->dev,
			    "%s - failed resubmitting read urb, error %d\n",
							__func__, result);
	}

	return result;
}
EXPORT_SYMBOL_GPL(usb_serial_generic_open);

static void generic_cleanup(struct usb_serial_port *port)
{
	struct usb_serial *serial = port->serial;

	dbg("%s - port %d", __func__, port->number);

	if (serial->dev) {
		/* shutdown any bulk reads that might be going on */
		if (serial->num_bulk_out)
			usb_kill_urb(port->write_urb);
		if (serial->num_bulk_in)
			usb_kill_urb(port->read_urb);
	}
}

void usb_serial_generic_close(struct usb_serial_port *port)
{
	dbg("%s - port %d", __func__, port->number);
	generic_cleanup(port);
}

static int usb_serial_multi_urb_write(struct tty_struct *tty,
	struct usb_serial_port *port, const unsigned char *buf, int count)
{
	unsigned long flags;
	struct urb *urb;
	unsigned char *buffer;
	int status;
	int towrite;
	int bwrite = 0;

	dbg("%s - port %d", __func__, port->number);

	if (count == 0)
		dbg("%s - write request of 0 bytes", __func__);

	while (count > 0) {
		towrite = (count > port->bulk_out_size) ?
			port->bulk_out_size : count;
		spin_lock_irqsave(&port->lock, flags);
		if (port->urbs_in_flight >
		    port->serial->type->max_in_flight_urbs) {
			spin_unlock_irqrestore(&port->lock, flags);
			dbg("%s - write limit hit\n", __func__);
			return bwrite;
		}
		port->tx_bytes_flight += towrite;
		port->urbs_in_flight++;
		spin_unlock_irqrestore(&port->lock, flags);

		buffer = kmalloc(towrite, GFP_ATOMIC);
		if (!buffer) {
			dev_err(&port->dev,
			"%s ran out of kernel memory for urb ...\n", __func__);
			goto error_no_buffer;
		}

		urb = usb_alloc_urb(0, GFP_ATOMIC);
		if (!urb) {
			dev_err(&port->dev, "%s - no more free urbs\n",
				__func__);
			goto error_no_urb;
		}

		/* Copy data */
		memcpy(buffer, buf + bwrite, towrite);
		usb_serial_debug_data(debug, &port->dev, __func__,
				      towrite, buffer);
		/* fill the buffer and send it */
		usb_fill_bulk_urb(urb, port->serial->dev,
			usb_sndbulkpipe(port->serial->dev,
					port->bulk_out_endpointAddress),
			buffer, towrite,
			usb_serial_generic_write_bulk_callback, port);

		status = usb_submit_urb(urb, GFP_ATOMIC);
		if (status) {
			dev_err(&port->dev,
				"%s - failed submitting write urb, error %d\n",
				__func__, status);
			goto error;
		}

		/* This urb is the responsibility of the host driver now */
		usb_free_urb(urb);
		dbg("%s write: %d", __func__, towrite);
		count -= towrite;
		bwrite += towrite;
	}
	return bwrite;

error:
	usb_free_urb(urb);
error_no_urb:
	kfree(buffer);
error_no_buffer:
	spin_lock_irqsave(&port->lock, flags);
	port->urbs_in_flight--;
	port->tx_bytes_flight -= towrite;
	spin_unlock_irqrestore(&port->lock, flags);
	return bwrite;
}

/**
 * usb_serial_generic_write_start - kick off an URB write
 * @port:	Pointer to the &struct usb_serial_port data
 *
 * Returns the number of bytes queued on success. This will be zero if there
 * was nothing to send. Otherwise, it returns a negative errno value
 */
static int usb_serial_generic_write_start(struct usb_serial_port *port)
{
	struct usb_serial *serial = port->serial;
	unsigned char *data;
	int result;
	int count;
	unsigned long flags;
	bool start_io;

	/* Atomically determine whether we can and need to start a USB
	 * operation. */
	spin_lock_irqsave(&port->lock, flags);
	if (port->write_urb_busy)
		start_io = false;
	else {
		start_io = (kfifo_len(&port->write_fifo) != 0);
		port->write_urb_busy = start_io;
	}
	spin_unlock_irqrestore(&port->lock, flags);

	if (!start_io)
		return 0;

	data = port->write_urb->transfer_buffer;
	count = kfifo_out_locked(&port->write_fifo, data, port->bulk_out_size, &port->lock);
	usb_serial_debug_data(debug, &port->dev, __func__, count, data);

	/* set up our urb */
	usb_fill_bulk_urb(port->write_urb, serial->dev,
			   usb_sndbulkpipe(serial->dev,
				port->bulk_out_endpointAddress),
			   port->write_urb->transfer_buffer, count,
			   ((serial->type->write_bulk_callback) ?
			     serial->type->write_bulk_callback :
			     usb_serial_generic_write_bulk_callback),
			   port);

	/* send the data out the bulk port */
	result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
	if (result) {
		dev_err(&port->dev,
			"%s - failed submitting write urb, error %d\n",
						__func__, result);
		/* don't have to grab the lock here, as we will
		   retry if != 0 */
		port->write_urb_busy = 0;
	} else
		result = count;

	return result;
}

/**
 * usb_serial_generic_write - generic write function for serial USB devices
 * @tty:	Pointer to &struct tty_struct for the device
 * @port:	Pointer to the &usb_serial_port structure for the device
 * @buf:	Pointer to the data to write
 * @count:	Number of bytes to write
 *
 * Returns the number of characters actually written, which may be anything
 * from zero to @count. If an error occurs, it returns the negative errno
 * value.
 */
int usb_serial_generic_write(struct tty_struct *tty,
	struct usb_serial_port *port, const unsigned char *buf, int count)
{
	struct usb_serial *serial = port->serial;
	int result;

	dbg("%s - port %d", __func__, port->number);

	if (count == 0) {
		dbg("%s - write request of 0 bytes", __func__);
		return 0;
	}

	/* only do something if we have a bulk out endpoint */
	if (!serial->num_bulk_out)
		return 0;

	if (serial->type->max_in_flight_urbs)
		return usb_serial_multi_urb_write(tty, port,
						  buf, count);

	count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
	result = usb_serial_generic_write_start(port);

	if (result >= 0)
		result = count;

	return result;
}
EXPORT_SYMBOL_GPL(usb_serial_generic_write);

int usb_serial_generic_write_room(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct usb_serial *serial = port->serial;
	unsigned long flags;
	int room = 0;

	dbg("%s - port %d", __func__, port->number);
	spin_lock_irqsave(&port->lock, flags);
	if (serial->type->max_in_flight_urbs) {
		if (port->urbs_in_flight < serial->type->max_in_flight_urbs)
			room = port->bulk_out_size *
				(serial->type->max_in_flight_urbs -
				 port->urbs_in_flight);
	} else if (serial->num_bulk_out)
		room = kfifo_avail(&port->write_fifo);
	spin_unlock_irqrestore(&port->lock, flags);

	dbg("%s - returns %d", __func__, room);
	return room;
}

int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct usb_serial *serial = port->serial;
	int chars = 0;
	unsigned long flags;

	dbg("%s - port %d", __func__, port->number);

	spin_lock_irqsave(&port->lock, flags);
	if (serial->type->max_in_flight_urbs)
		chars = port->tx_bytes_flight;
	else if (serial->num_bulk_out)
		chars = kfifo_len(&port->write_fifo);
	spin_unlock_irqrestore(&port->lock, flags);

	dbg("%s - returns %d", __func__, chars);
	return chars;
}


void usb_serial_generic_resubmit_read_urb(struct usb_serial_port *port,
			gfp_t mem_flags)
{
	struct urb *urb = port->read_urb;
	struct usb_serial *serial = port->serial;
	int result;

	/* Continue reading from device */
	usb_fill_bulk_urb(urb, serial->dev,
			   usb_rcvbulkpipe(serial->dev,
					port->bulk_in_endpointAddress),
			   urb->transfer_buffer,
			   urb->transfer_buffer_length,
			   ((serial->type->read_bulk_callback) ?
			     serial->type->read_bulk_callback :
			     usb_serial_generic_read_bulk_callback), port);
	result = usb_submit_urb(urb, mem_flags);
	if (result)
		dev_err(&port->dev,
			"%s - failed resubmitting read urb, error %d\n",
							__func__, result);
}
EXPORT_SYMBOL_GPL(usb_serial_generic_resubmit_read_urb);

/* Push data to tty layer and resubmit the bulk read URB */
static void flush_and_resubmit_read_urb(struct usb_serial_port *port)
{
	struct urb *urb = port->read_urb;
	struct tty_struct *tty = tty_port_tty_get(&port->port);
	char *ch = (char *)urb->transfer_buffer;
	int i;

	if (!tty)
		goto done;

	/* The per character mucking around with sysrq path it too slow for
	   stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
	   where the USB serial is not a console anyway */
	if (!port->console || !port->sysrq)
		tty_insert_flip_string(tty, ch, urb->actual_length);
	else {
		/* Push data to tty */
		for (i = 0; i < urb->actual_length; i++, ch++) {
			if (!usb_serial_handle_sysrq_char(tty, port, *ch))
				tty_insert_flip_char(tty, *ch, TTY_NORMAL);
		}
	}
	tty_flip_buffer_push(tty);
	tty_kref_put(tty);
done:
	usb_serial_generic_resubmit_read_urb(port, GFP_ATOMIC);
}

void usb_serial_generic_read_bulk_callback(struct urb *urb)
{
	struct usb_serial_port *port = urb->context;
	unsigned char *data = urb->transfer_buffer;
	int status = urb->status;
	unsigned long flags;

	dbg("%s - port %d", __func__, port->number);

	if (unlikely(status != 0)) {
		dbg("%s - nonzero read bulk status received: %d",
		    __func__, status);
		return;
	}

	usb_serial_debug_data(debug, &port->dev, __func__,
						urb->actual_length, data);

	/* Throttle the device if requested by tty */
	spin_lock_irqsave(&port->lock, flags);
	port->throttled = port->throttle_req;
	if (!port->throttled) {
		spin_unlock_irqrestore(&port->lock, flags);
		flush_and_resubmit_read_urb(port);
	} else
		spin_unlock_irqrestore(&port->lock, flags);
}
EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);

void usb_serial_generic_write_bulk_callback(struct urb *urb)
{
	unsigned long flags;
	struct usb_serial_port *port = urb->context;
	int status = urb->status;

	dbg("%s - port %d", __func__, port->number);

	if (port->serial->type->max_in_flight_urbs) {
		kfree(urb->transfer_buffer);

		spin_lock_irqsave(&port->lock, flags);
		--port->urbs_in_flight;
		port->tx_bytes_flight -= urb->transfer_buffer_length;
		if (port->urbs_in_flight < 0)
			port->urbs_in_flight = 0;
		spin_unlock_irqrestore(&port->lock, flags);

		if (status) {
			dbg("%s - nonzero multi-urb write bulk status "
				"received: %d", __func__, status);
			return;
		}
	} else {
		port->write_urb_busy = 0;

		if (status) {
			dbg("%s - nonzero multi-urb write bulk status "
				"received: %d", __func__, status);
			kfifo_reset_out(&port->write_fifo);
		} else
			usb_serial_generic_write_start(port);
	}

	usb_serial_port_softint(port);
}
EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);

void usb_serial_generic_throttle(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	unsigned long flags;

	dbg("%s - port %d", __func__, port->number);

	/* Set the throttle request flag. It will be picked up
	 * by usb_serial_generic_read_bulk_callback(). */
	spin_lock_irqsave(&port->lock, flags);
	port->throttle_req = 1;
	spin_unlock_irqrestore(&port->lock, flags);
}

void usb_serial_generic_unthrottle(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	int was_throttled;
	unsigned long flags;

	dbg("%s - port %d", __func__, port->number);

	/* Clear the throttle flags */
	spin_lock_irqsave(&port->lock, flags);
	was_throttled = port->throttled;
	port->throttled = port->throttle_req = 0;
	spin_unlock_irqrestore(&port->lock, flags);

	if (was_throttled) {
		/* Resume reading from device */
		flush_and_resubmit_read_urb(port);
	}
}

int usb_serial_handle_sysrq_char(struct tty_struct *tty,
			struct usb_serial_port *port, unsigned int ch)
{
	if (port->sysrq && port->console) {
		if (ch && time_before(jiffies, port->sysrq)) {
			handle_sysrq(ch, tty);
			port->sysrq = 0;
			return 1;
		}
		port->sysrq = 0;
	}
	return 0;
}
EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);

int usb_serial_handle_break(struct usb_serial_port *port)
{
	if (!port->sysrq) {
		port->sysrq = jiffies + HZ*5;
		return 1;
	}
	port->sysrq = 0;
	return 0;
}
EXPORT_SYMBOL_GPL(usb_serial_handle_break);

int usb_serial_generic_resume(struct usb_serial *serial)
{
	struct usb_serial_port *port;
	int i, c = 0, r;

	for (i = 0; i < serial->num_ports; i++) {
		port = serial->port[i];
		if (!port->port.count)
			continue;

		if (port->read_urb) {
			r = usb_submit_urb(port->read_urb, GFP_NOIO);
			if (r < 0)
				c++;
		}

		if (port->write_urb) {
			r = usb_serial_generic_write_start(port);
			if (r < 0)
				c++;
		}
	}

	return c ? -EIO : 0;
}
EXPORT_SYMBOL_GPL(usb_serial_generic_resume);

void usb_serial_generic_disconnect(struct usb_serial *serial)
{
	int i;

	dbg("%s", __func__);

	/* stop reads and writes on all ports */
	for (i = 0; i < serial->num_ports; ++i)
		generic_cleanup(serial->port[i]);
}

void usb_serial_generic_release(struct usb_serial *serial)
{
	dbg("%s", __func__);
}