xref: /linux/drivers/usb/serial/usb-serial.c (revision e9f0878c4b2004ac19581274c1ae4c61ae3ca70e)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * USB Serial Converter driver
4  *
5  * Copyright (C) 2009 - 2013 Johan Hovold (jhovold@gmail.com)
6  * Copyright (C) 1999 - 2012 Greg Kroah-Hartman (greg@kroah.com)
7  * Copyright (C) 2000 Peter Berger (pberger@brimson.com)
8  * Copyright (C) 2000 Al Borchers (borchers@steinerpoint.com)
9  *
10  * This driver was originally based on the ACM driver by Armin Fuerst (which was
11  * based on a driver by Brad Keryan)
12  *
13  * See Documentation/usb/usb-serial.txt for more information on using this
14  * driver
15  */
16 
17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18 
19 #include <linux/kernel.h>
20 #include <linux/errno.h>
21 #include <linux/init.h>
22 #include <linux/slab.h>
23 #include <linux/tty.h>
24 #include <linux/tty_driver.h>
25 #include <linux/tty_flip.h>
26 #include <linux/module.h>
27 #include <linux/moduleparam.h>
28 #include <linux/seq_file.h>
29 #include <linux/spinlock.h>
30 #include <linux/mutex.h>
31 #include <linux/list.h>
32 #include <linux/uaccess.h>
33 #include <linux/serial.h>
34 #include <linux/usb.h>
35 #include <linux/usb/serial.h>
36 #include <linux/kfifo.h>
37 #include <linux/idr.h>
38 
39 #define DRIVER_AUTHOR "Greg Kroah-Hartman <gregkh@linuxfoundation.org>"
40 #define DRIVER_DESC "USB Serial Driver core"
41 
42 #define USB_SERIAL_TTY_MAJOR	188
43 #define USB_SERIAL_TTY_MINORS	512	/* should be enough for a while */
44 
45 /* There is no MODULE_DEVICE_TABLE for usbserial.c.  Instead
46    the MODULE_DEVICE_TABLE declarations in each serial driver
47    cause the "hotplug" program to pull in whatever module is necessary
48    via modprobe, and modprobe will load usbserial because the serial
49    drivers depend on it.
50 */
51 
52 static DEFINE_IDR(serial_minors);
53 static DEFINE_MUTEX(table_lock);
54 static LIST_HEAD(usb_serial_driver_list);
55 
56 /*
57  * Look up the serial port structure.  If it is found and it hasn't been
58  * disconnected, return with the parent usb_serial structure's disc_mutex held
59  * and its refcount incremented.  Otherwise return NULL.
60  */
61 struct usb_serial_port *usb_serial_port_get_by_minor(unsigned minor)
62 {
63 	struct usb_serial *serial;
64 	struct usb_serial_port *port;
65 
66 	mutex_lock(&table_lock);
67 	port = idr_find(&serial_minors, minor);
68 	if (!port)
69 		goto exit;
70 
71 	serial = port->serial;
72 	mutex_lock(&serial->disc_mutex);
73 	if (serial->disconnected) {
74 		mutex_unlock(&serial->disc_mutex);
75 		port = NULL;
76 	} else {
77 		kref_get(&serial->kref);
78 	}
79 exit:
80 	mutex_unlock(&table_lock);
81 	return port;
82 }
83 
84 static int allocate_minors(struct usb_serial *serial, int num_ports)
85 {
86 	struct usb_serial_port *port;
87 	unsigned int i, j;
88 	int minor;
89 
90 	dev_dbg(&serial->interface->dev, "%s %d\n", __func__, num_ports);
91 
92 	mutex_lock(&table_lock);
93 	for (i = 0; i < num_ports; ++i) {
94 		port = serial->port[i];
95 		minor = idr_alloc(&serial_minors, port, 0,
96 					USB_SERIAL_TTY_MINORS, GFP_KERNEL);
97 		if (minor < 0)
98 			goto error;
99 		port->minor = minor;
100 		port->port_number = i;
101 	}
102 	serial->minors_reserved = 1;
103 	mutex_unlock(&table_lock);
104 	return 0;
105 error:
106 	/* unwind the already allocated minors */
107 	for (j = 0; j < i; ++j)
108 		idr_remove(&serial_minors, serial->port[j]->minor);
109 	mutex_unlock(&table_lock);
110 	return minor;
111 }
112 
113 static void release_minors(struct usb_serial *serial)
114 {
115 	int i;
116 
117 	mutex_lock(&table_lock);
118 	for (i = 0; i < serial->num_ports; ++i)
119 		idr_remove(&serial_minors, serial->port[i]->minor);
120 	mutex_unlock(&table_lock);
121 	serial->minors_reserved = 0;
122 }
123 
124 static void destroy_serial(struct kref *kref)
125 {
126 	struct usb_serial *serial;
127 	struct usb_serial_port *port;
128 	int i;
129 
130 	serial = to_usb_serial(kref);
131 
132 	/* return the minor range that this device had */
133 	if (serial->minors_reserved)
134 		release_minors(serial);
135 
136 	if (serial->attached && serial->type->release)
137 		serial->type->release(serial);
138 
139 	/* Now that nothing is using the ports, they can be freed */
140 	for (i = 0; i < serial->num_port_pointers; ++i) {
141 		port = serial->port[i];
142 		if (port) {
143 			port->serial = NULL;
144 			put_device(&port->dev);
145 		}
146 	}
147 
148 	usb_put_intf(serial->interface);
149 	usb_put_dev(serial->dev);
150 	kfree(serial);
151 }
152 
153 void usb_serial_put(struct usb_serial *serial)
154 {
155 	kref_put(&serial->kref, destroy_serial);
156 }
157 
158 /*****************************************************************************
159  * Driver tty interface functions
160  *****************************************************************************/
161 
162 /**
163  * serial_install - install tty
164  * @driver: the driver (USB in our case)
165  * @tty: the tty being created
166  *
167  * Create the termios objects for this tty.  We use the default
168  * USB serial settings but permit them to be overridden by
169  * serial->type->init_termios.
170  *
171  * This is the first place a new tty gets used.  Hence this is where we
172  * acquire references to the usb_serial structure and the driver module,
173  * where we store a pointer to the port, and where we do an autoresume.
174  * All these actions are reversed in serial_cleanup().
175  */
176 static int serial_install(struct tty_driver *driver, struct tty_struct *tty)
177 {
178 	int idx = tty->index;
179 	struct usb_serial *serial;
180 	struct usb_serial_port *port;
181 	int retval = -ENODEV;
182 
183 	port = usb_serial_port_get_by_minor(idx);
184 	if (!port)
185 		return retval;
186 
187 	serial = port->serial;
188 	if (!try_module_get(serial->type->driver.owner))
189 		goto error_module_get;
190 
191 	retval = usb_autopm_get_interface(serial->interface);
192 	if (retval)
193 		goto error_get_interface;
194 
195 	retval = tty_standard_install(driver, tty);
196 	if (retval)
197 		goto error_init_termios;
198 
199 	mutex_unlock(&serial->disc_mutex);
200 
201 	/* allow the driver to update the settings */
202 	if (serial->type->init_termios)
203 		serial->type->init_termios(tty);
204 
205 	tty->driver_data = port;
206 
207 	return retval;
208 
209  error_init_termios:
210 	usb_autopm_put_interface(serial->interface);
211  error_get_interface:
212 	module_put(serial->type->driver.owner);
213  error_module_get:
214 	usb_serial_put(serial);
215 	mutex_unlock(&serial->disc_mutex);
216 	return retval;
217 }
218 
219 static int serial_port_activate(struct tty_port *tport, struct tty_struct *tty)
220 {
221 	struct usb_serial_port *port =
222 		container_of(tport, struct usb_serial_port, port);
223 	struct usb_serial *serial = port->serial;
224 	int retval;
225 
226 	mutex_lock(&serial->disc_mutex);
227 	if (serial->disconnected)
228 		retval = -ENODEV;
229 	else
230 		retval = port->serial->type->open(tty, port);
231 	mutex_unlock(&serial->disc_mutex);
232 
233 	if (retval < 0)
234 		retval = usb_translate_errors(retval);
235 
236 	return retval;
237 }
238 
239 static int serial_open(struct tty_struct *tty, struct file *filp)
240 {
241 	struct usb_serial_port *port = tty->driver_data;
242 
243 	dev_dbg(tty->dev, "%s\n", __func__);
244 
245 	return tty_port_open(&port->port, tty, filp);
246 }
247 
248 /**
249  * serial_port_shutdown - shut down hardware
250  * @tport: tty port to shut down
251  *
252  * Shut down a USB serial port. Serialized against activate by the
253  * tport mutex and kept to matching open/close pairs
254  * of calls by the initialized flag.
255  *
256  * Not called if tty is console.
257  */
258 static void serial_port_shutdown(struct tty_port *tport)
259 {
260 	struct usb_serial_port *port =
261 		container_of(tport, struct usb_serial_port, port);
262 	struct usb_serial_driver *drv = port->serial->type;
263 
264 	if (drv->close)
265 		drv->close(port);
266 }
267 
268 static void serial_hangup(struct tty_struct *tty)
269 {
270 	struct usb_serial_port *port = tty->driver_data;
271 
272 	dev_dbg(tty->dev, "%s\n", __func__);
273 
274 	tty_port_hangup(&port->port);
275 }
276 
277 static void serial_close(struct tty_struct *tty, struct file *filp)
278 {
279 	struct usb_serial_port *port = tty->driver_data;
280 
281 	dev_dbg(tty->dev, "%s\n", __func__);
282 
283 	tty_port_close(&port->port, tty, filp);
284 }
285 
286 /**
287  * serial_cleanup - free resources post close/hangup
288  * @port: port to free up
289  *
290  * Do the resource freeing and refcount dropping for the port.
291  * Avoid freeing the console.
292  *
293  * Called asynchronously after the last tty kref is dropped.
294  */
295 static void serial_cleanup(struct tty_struct *tty)
296 {
297 	struct usb_serial_port *port = tty->driver_data;
298 	struct usb_serial *serial;
299 	struct module *owner;
300 
301 	dev_dbg(tty->dev, "%s\n", __func__);
302 
303 	/* The console is magical.  Do not hang up the console hardware
304 	 * or there will be tears.
305 	 */
306 	if (port->port.console)
307 		return;
308 
309 	tty->driver_data = NULL;
310 
311 	serial = port->serial;
312 	owner = serial->type->driver.owner;
313 
314 	mutex_lock(&serial->disc_mutex);
315 	if (!serial->disconnected)
316 		usb_autopm_put_interface(serial->interface);
317 	mutex_unlock(&serial->disc_mutex);
318 
319 	usb_serial_put(serial);
320 	module_put(owner);
321 }
322 
323 static int serial_write(struct tty_struct *tty, const unsigned char *buf,
324 								int count)
325 {
326 	struct usb_serial_port *port = tty->driver_data;
327 	int retval = -ENODEV;
328 
329 	if (port->serial->dev->state == USB_STATE_NOTATTACHED)
330 		goto exit;
331 
332 	dev_dbg(tty->dev, "%s - %d byte(s)\n", __func__, count);
333 
334 	retval = port->serial->type->write(tty, port, buf, count);
335 	if (retval < 0)
336 		retval = usb_translate_errors(retval);
337 exit:
338 	return retval;
339 }
340 
341 static int serial_write_room(struct tty_struct *tty)
342 {
343 	struct usb_serial_port *port = tty->driver_data;
344 
345 	dev_dbg(tty->dev, "%s\n", __func__);
346 
347 	return port->serial->type->write_room(tty);
348 }
349 
350 static int serial_chars_in_buffer(struct tty_struct *tty)
351 {
352 	struct usb_serial_port *port = tty->driver_data;
353 	struct usb_serial *serial = port->serial;
354 
355 	dev_dbg(tty->dev, "%s\n", __func__);
356 
357 	if (serial->disconnected)
358 		return 0;
359 
360 	return serial->type->chars_in_buffer(tty);
361 }
362 
363 static void serial_wait_until_sent(struct tty_struct *tty, int timeout)
364 {
365 	struct usb_serial_port *port = tty->driver_data;
366 	struct usb_serial *serial = port->serial;
367 
368 	dev_dbg(tty->dev, "%s\n", __func__);
369 
370 	if (!port->serial->type->wait_until_sent)
371 		return;
372 
373 	mutex_lock(&serial->disc_mutex);
374 	if (!serial->disconnected)
375 		port->serial->type->wait_until_sent(tty, timeout);
376 	mutex_unlock(&serial->disc_mutex);
377 }
378 
379 static void serial_throttle(struct tty_struct *tty)
380 {
381 	struct usb_serial_port *port = tty->driver_data;
382 
383 	dev_dbg(tty->dev, "%s\n", __func__);
384 
385 	if (port->serial->type->throttle)
386 		port->serial->type->throttle(tty);
387 }
388 
389 static void serial_unthrottle(struct tty_struct *tty)
390 {
391 	struct usb_serial_port *port = tty->driver_data;
392 
393 	dev_dbg(tty->dev, "%s\n", __func__);
394 
395 	if (port->serial->type->unthrottle)
396 		port->serial->type->unthrottle(tty);
397 }
398 
399 static int serial_ioctl(struct tty_struct *tty,
400 					unsigned int cmd, unsigned long arg)
401 {
402 	struct usb_serial_port *port = tty->driver_data;
403 	int retval = -ENOIOCTLCMD;
404 
405 	dev_dbg(tty->dev, "%s - cmd 0x%04x\n", __func__, cmd);
406 
407 	switch (cmd) {
408 	case TIOCMIWAIT:
409 		if (port->serial->type->tiocmiwait)
410 			retval = port->serial->type->tiocmiwait(tty, arg);
411 		break;
412 	default:
413 		if (port->serial->type->ioctl)
414 			retval = port->serial->type->ioctl(tty, cmd, arg);
415 	}
416 
417 	return retval;
418 }
419 
420 static void serial_set_termios(struct tty_struct *tty, struct ktermios *old)
421 {
422 	struct usb_serial_port *port = tty->driver_data;
423 
424 	dev_dbg(tty->dev, "%s\n", __func__);
425 
426 	if (port->serial->type->set_termios)
427 		port->serial->type->set_termios(tty, port, old);
428 	else
429 		tty_termios_copy_hw(&tty->termios, old);
430 }
431 
432 static int serial_break(struct tty_struct *tty, int break_state)
433 {
434 	struct usb_serial_port *port = tty->driver_data;
435 
436 	dev_dbg(tty->dev, "%s\n", __func__);
437 
438 	if (port->serial->type->break_ctl)
439 		port->serial->type->break_ctl(tty, break_state);
440 
441 	return 0;
442 }
443 
444 static int serial_proc_show(struct seq_file *m, void *v)
445 {
446 	struct usb_serial *serial;
447 	struct usb_serial_port *port;
448 	int i;
449 	char tmp[40];
450 
451 	seq_puts(m, "usbserinfo:1.0 driver:2.0\n");
452 	for (i = 0; i < USB_SERIAL_TTY_MINORS; ++i) {
453 		port = usb_serial_port_get_by_minor(i);
454 		if (port == NULL)
455 			continue;
456 		serial = port->serial;
457 
458 		seq_printf(m, "%d:", i);
459 		if (serial->type->driver.owner)
460 			seq_printf(m, " module:%s",
461 				module_name(serial->type->driver.owner));
462 		seq_printf(m, " name:\"%s\"",
463 				serial->type->description);
464 		seq_printf(m, " vendor:%04x product:%04x",
465 			le16_to_cpu(serial->dev->descriptor.idVendor),
466 			le16_to_cpu(serial->dev->descriptor.idProduct));
467 		seq_printf(m, " num_ports:%d", serial->num_ports);
468 		seq_printf(m, " port:%d", port->port_number);
469 		usb_make_path(serial->dev, tmp, sizeof(tmp));
470 		seq_printf(m, " path:%s", tmp);
471 
472 		seq_putc(m, '\n');
473 		usb_serial_put(serial);
474 		mutex_unlock(&serial->disc_mutex);
475 	}
476 	return 0;
477 }
478 
479 static int serial_tiocmget(struct tty_struct *tty)
480 {
481 	struct usb_serial_port *port = tty->driver_data;
482 
483 	dev_dbg(tty->dev, "%s\n", __func__);
484 
485 	if (port->serial->type->tiocmget)
486 		return port->serial->type->tiocmget(tty);
487 	return -EINVAL;
488 }
489 
490 static int serial_tiocmset(struct tty_struct *tty,
491 			    unsigned int set, unsigned int clear)
492 {
493 	struct usb_serial_port *port = tty->driver_data;
494 
495 	dev_dbg(tty->dev, "%s\n", __func__);
496 
497 	if (port->serial->type->tiocmset)
498 		return port->serial->type->tiocmset(tty, set, clear);
499 	return -EINVAL;
500 }
501 
502 static int serial_get_icount(struct tty_struct *tty,
503 				struct serial_icounter_struct *icount)
504 {
505 	struct usb_serial_port *port = tty->driver_data;
506 
507 	dev_dbg(tty->dev, "%s\n", __func__);
508 
509 	if (port->serial->type->get_icount)
510 		return port->serial->type->get_icount(tty, icount);
511 	return -EINVAL;
512 }
513 
514 /*
515  * We would be calling tty_wakeup here, but unfortunately some line
516  * disciplines have an annoying habit of calling tty->write from
517  * the write wakeup callback (e.g. n_hdlc.c).
518  */
519 void usb_serial_port_softint(struct usb_serial_port *port)
520 {
521 	schedule_work(&port->work);
522 }
523 EXPORT_SYMBOL_GPL(usb_serial_port_softint);
524 
525 static void usb_serial_port_work(struct work_struct *work)
526 {
527 	struct usb_serial_port *port =
528 		container_of(work, struct usb_serial_port, work);
529 
530 	tty_port_tty_wakeup(&port->port);
531 }
532 
533 static void usb_serial_port_poison_urbs(struct usb_serial_port *port)
534 {
535 	int i;
536 
537 	for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
538 		usb_poison_urb(port->read_urbs[i]);
539 	for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
540 		usb_poison_urb(port->write_urbs[i]);
541 
542 	usb_poison_urb(port->interrupt_in_urb);
543 	usb_poison_urb(port->interrupt_out_urb);
544 }
545 
546 static void usb_serial_port_unpoison_urbs(struct usb_serial_port *port)
547 {
548 	int i;
549 
550 	for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
551 		usb_unpoison_urb(port->read_urbs[i]);
552 	for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
553 		usb_unpoison_urb(port->write_urbs[i]);
554 
555 	usb_unpoison_urb(port->interrupt_in_urb);
556 	usb_unpoison_urb(port->interrupt_out_urb);
557 }
558 
559 static void usb_serial_port_release(struct device *dev)
560 {
561 	struct usb_serial_port *port = to_usb_serial_port(dev);
562 	int i;
563 
564 	dev_dbg(dev, "%s\n", __func__);
565 
566 	usb_free_urb(port->interrupt_in_urb);
567 	usb_free_urb(port->interrupt_out_urb);
568 	for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
569 		usb_free_urb(port->read_urbs[i]);
570 		kfree(port->bulk_in_buffers[i]);
571 	}
572 	for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) {
573 		usb_free_urb(port->write_urbs[i]);
574 		kfree(port->bulk_out_buffers[i]);
575 	}
576 	kfifo_free(&port->write_fifo);
577 	kfree(port->interrupt_in_buffer);
578 	kfree(port->interrupt_out_buffer);
579 	tty_port_destroy(&port->port);
580 	kfree(port);
581 }
582 
583 static struct usb_serial *create_serial(struct usb_device *dev,
584 					struct usb_interface *interface,
585 					struct usb_serial_driver *driver)
586 {
587 	struct usb_serial *serial;
588 
589 	serial = kzalloc(sizeof(*serial), GFP_KERNEL);
590 	if (!serial)
591 		return NULL;
592 	serial->dev = usb_get_dev(dev);
593 	serial->type = driver;
594 	serial->interface = usb_get_intf(interface);
595 	kref_init(&serial->kref);
596 	mutex_init(&serial->disc_mutex);
597 	serial->minors_reserved = 0;
598 
599 	return serial;
600 }
601 
602 static const struct usb_device_id *match_dynamic_id(struct usb_interface *intf,
603 					    struct usb_serial_driver *drv)
604 {
605 	struct usb_dynid *dynid;
606 
607 	spin_lock(&drv->dynids.lock);
608 	list_for_each_entry(dynid, &drv->dynids.list, node) {
609 		if (usb_match_one_id(intf, &dynid->id)) {
610 			spin_unlock(&drv->dynids.lock);
611 			return &dynid->id;
612 		}
613 	}
614 	spin_unlock(&drv->dynids.lock);
615 	return NULL;
616 }
617 
618 static const struct usb_device_id *get_iface_id(struct usb_serial_driver *drv,
619 						struct usb_interface *intf)
620 {
621 	const struct usb_device_id *id;
622 
623 	id = usb_match_id(intf, drv->id_table);
624 	if (id) {
625 		dev_dbg(&intf->dev, "static descriptor matches\n");
626 		goto exit;
627 	}
628 	id = match_dynamic_id(intf, drv);
629 	if (id)
630 		dev_dbg(&intf->dev, "dynamic descriptor matches\n");
631 exit:
632 	return id;
633 }
634 
635 /* Caller must hold table_lock */
636 static struct usb_serial_driver *search_serial_device(
637 					struct usb_interface *iface)
638 {
639 	const struct usb_device_id *id = NULL;
640 	struct usb_serial_driver *drv;
641 	struct usb_driver *driver = to_usb_driver(iface->dev.driver);
642 
643 	/* Check if the usb id matches a known device */
644 	list_for_each_entry(drv, &usb_serial_driver_list, driver_list) {
645 		if (drv->usb_driver == driver)
646 			id = get_iface_id(drv, iface);
647 		if (id)
648 			return drv;
649 	}
650 
651 	return NULL;
652 }
653 
654 static int serial_port_carrier_raised(struct tty_port *port)
655 {
656 	struct usb_serial_port *p = container_of(port, struct usb_serial_port, port);
657 	struct usb_serial_driver *drv = p->serial->type;
658 
659 	if (drv->carrier_raised)
660 		return drv->carrier_raised(p);
661 	/* No carrier control - don't block */
662 	return 1;
663 }
664 
665 static void serial_port_dtr_rts(struct tty_port *port, int on)
666 {
667 	struct usb_serial_port *p = container_of(port, struct usb_serial_port, port);
668 	struct usb_serial_driver *drv = p->serial->type;
669 
670 	if (drv->dtr_rts)
671 		drv->dtr_rts(p, on);
672 }
673 
674 static ssize_t port_number_show(struct device *dev,
675 				struct device_attribute *attr, char *buf)
676 {
677 	struct usb_serial_port *port = to_usb_serial_port(dev);
678 
679 	return sprintf(buf, "%u\n", port->port_number);
680 }
681 static DEVICE_ATTR_RO(port_number);
682 
683 static struct attribute *usb_serial_port_attrs[] = {
684 	&dev_attr_port_number.attr,
685 	NULL
686 };
687 ATTRIBUTE_GROUPS(usb_serial_port);
688 
689 static const struct tty_port_operations serial_port_ops = {
690 	.carrier_raised		= serial_port_carrier_raised,
691 	.dtr_rts		= serial_port_dtr_rts,
692 	.activate		= serial_port_activate,
693 	.shutdown		= serial_port_shutdown,
694 };
695 
696 static void find_endpoints(struct usb_serial *serial,
697 					struct usb_serial_endpoints *epds)
698 {
699 	struct device *dev = &serial->interface->dev;
700 	struct usb_host_interface *iface_desc;
701 	struct usb_endpoint_descriptor *epd;
702 	unsigned int i;
703 
704 	BUILD_BUG_ON(ARRAY_SIZE(epds->bulk_in) < USB_MAXENDPOINTS / 2);
705 	BUILD_BUG_ON(ARRAY_SIZE(epds->bulk_out) < USB_MAXENDPOINTS / 2);
706 	BUILD_BUG_ON(ARRAY_SIZE(epds->interrupt_in) < USB_MAXENDPOINTS / 2);
707 	BUILD_BUG_ON(ARRAY_SIZE(epds->interrupt_out) < USB_MAXENDPOINTS / 2);
708 
709 	iface_desc = serial->interface->cur_altsetting;
710 	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
711 		epd = &iface_desc->endpoint[i].desc;
712 
713 		if (usb_endpoint_is_bulk_in(epd)) {
714 			dev_dbg(dev, "found bulk in on endpoint %u\n", i);
715 			epds->bulk_in[epds->num_bulk_in++] = epd;
716 		} else if (usb_endpoint_is_bulk_out(epd)) {
717 			dev_dbg(dev, "found bulk out on endpoint %u\n", i);
718 			epds->bulk_out[epds->num_bulk_out++] = epd;
719 		} else if (usb_endpoint_is_int_in(epd)) {
720 			dev_dbg(dev, "found interrupt in on endpoint %u\n", i);
721 			epds->interrupt_in[epds->num_interrupt_in++] = epd;
722 		} else if (usb_endpoint_is_int_out(epd)) {
723 			dev_dbg(dev, "found interrupt out on endpoint %u\n", i);
724 			epds->interrupt_out[epds->num_interrupt_out++] = epd;
725 		}
726 	}
727 }
728 
729 static int setup_port_bulk_in(struct usb_serial_port *port,
730 					struct usb_endpoint_descriptor *epd)
731 {
732 	struct usb_serial_driver *type = port->serial->type;
733 	struct usb_device *udev = port->serial->dev;
734 	int buffer_size;
735 	int i;
736 
737 	buffer_size = max_t(int, type->bulk_in_size, usb_endpoint_maxp(epd));
738 	port->bulk_in_size = buffer_size;
739 	port->bulk_in_endpointAddress = epd->bEndpointAddress;
740 
741 	for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
742 		set_bit(i, &port->read_urbs_free);
743 		port->read_urbs[i] = usb_alloc_urb(0, GFP_KERNEL);
744 		if (!port->read_urbs[i])
745 			return -ENOMEM;
746 		port->bulk_in_buffers[i] = kmalloc(buffer_size, GFP_KERNEL);
747 		if (!port->bulk_in_buffers[i])
748 			return -ENOMEM;
749 		usb_fill_bulk_urb(port->read_urbs[i], udev,
750 				usb_rcvbulkpipe(udev, epd->bEndpointAddress),
751 				port->bulk_in_buffers[i], buffer_size,
752 				type->read_bulk_callback, port);
753 	}
754 
755 	port->read_urb = port->read_urbs[0];
756 	port->bulk_in_buffer = port->bulk_in_buffers[0];
757 
758 	return 0;
759 }
760 
761 static int setup_port_bulk_out(struct usb_serial_port *port,
762 					struct usb_endpoint_descriptor *epd)
763 {
764 	struct usb_serial_driver *type = port->serial->type;
765 	struct usb_device *udev = port->serial->dev;
766 	int buffer_size;
767 	int i;
768 
769 	if (kfifo_alloc(&port->write_fifo, PAGE_SIZE, GFP_KERNEL))
770 		return -ENOMEM;
771 	if (type->bulk_out_size)
772 		buffer_size = type->bulk_out_size;
773 	else
774 		buffer_size = usb_endpoint_maxp(epd);
775 	port->bulk_out_size = buffer_size;
776 	port->bulk_out_endpointAddress = epd->bEndpointAddress;
777 
778 	for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) {
779 		set_bit(i, &port->write_urbs_free);
780 		port->write_urbs[i] = usb_alloc_urb(0, GFP_KERNEL);
781 		if (!port->write_urbs[i])
782 			return -ENOMEM;
783 		port->bulk_out_buffers[i] = kmalloc(buffer_size, GFP_KERNEL);
784 		if (!port->bulk_out_buffers[i])
785 			return -ENOMEM;
786 		usb_fill_bulk_urb(port->write_urbs[i], udev,
787 				usb_sndbulkpipe(udev, epd->bEndpointAddress),
788 				port->bulk_out_buffers[i], buffer_size,
789 				type->write_bulk_callback, port);
790 	}
791 
792 	port->write_urb = port->write_urbs[0];
793 	port->bulk_out_buffer = port->bulk_out_buffers[0];
794 
795 	return 0;
796 }
797 
798 static int setup_port_interrupt_in(struct usb_serial_port *port,
799 					struct usb_endpoint_descriptor *epd)
800 {
801 	struct usb_serial_driver *type = port->serial->type;
802 	struct usb_device *udev = port->serial->dev;
803 	int buffer_size;
804 
805 	port->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
806 	if (!port->interrupt_in_urb)
807 		return -ENOMEM;
808 	buffer_size = usb_endpoint_maxp(epd);
809 	port->interrupt_in_endpointAddress = epd->bEndpointAddress;
810 	port->interrupt_in_buffer = kmalloc(buffer_size, GFP_KERNEL);
811 	if (!port->interrupt_in_buffer)
812 		return -ENOMEM;
813 	usb_fill_int_urb(port->interrupt_in_urb, udev,
814 			usb_rcvintpipe(udev, epd->bEndpointAddress),
815 			port->interrupt_in_buffer, buffer_size,
816 			type->read_int_callback, port,
817 			epd->bInterval);
818 
819 	return 0;
820 }
821 
822 static int setup_port_interrupt_out(struct usb_serial_port *port,
823 					struct usb_endpoint_descriptor *epd)
824 {
825 	struct usb_serial_driver *type = port->serial->type;
826 	struct usb_device *udev = port->serial->dev;
827 	int buffer_size;
828 
829 	port->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
830 	if (!port->interrupt_out_urb)
831 		return -ENOMEM;
832 	buffer_size = usb_endpoint_maxp(epd);
833 	port->interrupt_out_size = buffer_size;
834 	port->interrupt_out_endpointAddress = epd->bEndpointAddress;
835 	port->interrupt_out_buffer = kmalloc(buffer_size, GFP_KERNEL);
836 	if (!port->interrupt_out_buffer)
837 		return -ENOMEM;
838 	usb_fill_int_urb(port->interrupt_out_urb, udev,
839 			usb_sndintpipe(udev, epd->bEndpointAddress),
840 			port->interrupt_out_buffer, buffer_size,
841 			type->write_int_callback, port,
842 			epd->bInterval);
843 
844 	return 0;
845 }
846 
847 static int usb_serial_probe(struct usb_interface *interface,
848 			       const struct usb_device_id *id)
849 {
850 	struct device *ddev = &interface->dev;
851 	struct usb_device *dev = interface_to_usbdev(interface);
852 	struct usb_serial *serial = NULL;
853 	struct usb_serial_port *port;
854 	struct usb_serial_endpoints *epds;
855 	struct usb_serial_driver *type = NULL;
856 	int retval;
857 	int i;
858 	int num_ports = 0;
859 	unsigned char max_endpoints;
860 
861 	mutex_lock(&table_lock);
862 	type = search_serial_device(interface);
863 	if (!type) {
864 		mutex_unlock(&table_lock);
865 		dev_dbg(ddev, "none matched\n");
866 		return -ENODEV;
867 	}
868 
869 	if (!try_module_get(type->driver.owner)) {
870 		mutex_unlock(&table_lock);
871 		dev_err(ddev, "module get failed, exiting\n");
872 		return -EIO;
873 	}
874 	mutex_unlock(&table_lock);
875 
876 	serial = create_serial(dev, interface, type);
877 	if (!serial) {
878 		retval = -ENOMEM;
879 		goto err_put_module;
880 	}
881 
882 	/* if this device type has a probe function, call it */
883 	if (type->probe) {
884 		const struct usb_device_id *id;
885 
886 		id = get_iface_id(type, interface);
887 		retval = type->probe(serial, id);
888 
889 		if (retval) {
890 			dev_dbg(ddev, "sub driver rejected device\n");
891 			goto err_put_serial;
892 		}
893 	}
894 
895 	/* descriptor matches, let's find the endpoints needed */
896 	epds = kzalloc(sizeof(*epds), GFP_KERNEL);
897 	if (!epds) {
898 		retval = -ENOMEM;
899 		goto err_put_serial;
900 	}
901 
902 	find_endpoints(serial, epds);
903 
904 	if (epds->num_bulk_in < type->num_bulk_in ||
905 			epds->num_bulk_out < type->num_bulk_out ||
906 			epds->num_interrupt_in < type->num_interrupt_in ||
907 			epds->num_interrupt_out < type->num_interrupt_out) {
908 		dev_err(ddev, "required endpoints missing\n");
909 		retval = -ENODEV;
910 		goto err_free_epds;
911 	}
912 
913 	if (type->calc_num_ports) {
914 		retval = type->calc_num_ports(serial, epds);
915 		if (retval < 0)
916 			goto err_free_epds;
917 		num_ports = retval;
918 	}
919 
920 	if (!num_ports)
921 		num_ports = type->num_ports;
922 
923 	if (num_ports > MAX_NUM_PORTS) {
924 		dev_warn(ddev, "too many ports requested: %d\n", num_ports);
925 		num_ports = MAX_NUM_PORTS;
926 	}
927 
928 	serial->num_ports = (unsigned char)num_ports;
929 	serial->num_bulk_in = epds->num_bulk_in;
930 	serial->num_bulk_out = epds->num_bulk_out;
931 	serial->num_interrupt_in = epds->num_interrupt_in;
932 	serial->num_interrupt_out = epds->num_interrupt_out;
933 
934 	/* found all that we need */
935 	dev_info(ddev, "%s converter detected\n", type->description);
936 
937 	/* create our ports, we need as many as the max endpoints */
938 	/* we don't use num_ports here because some devices have more
939 	   endpoint pairs than ports */
940 	max_endpoints = max(epds->num_bulk_in, epds->num_bulk_out);
941 	max_endpoints = max(max_endpoints, epds->num_interrupt_in);
942 	max_endpoints = max(max_endpoints, epds->num_interrupt_out);
943 	max_endpoints = max(max_endpoints, serial->num_ports);
944 	serial->num_port_pointers = max_endpoints;
945 
946 	dev_dbg(ddev, "setting up %d port structure(s)\n", max_endpoints);
947 	for (i = 0; i < max_endpoints; ++i) {
948 		port = kzalloc(sizeof(struct usb_serial_port), GFP_KERNEL);
949 		if (!port) {
950 			retval = -ENOMEM;
951 			goto err_free_epds;
952 		}
953 		tty_port_init(&port->port);
954 		port->port.ops = &serial_port_ops;
955 		port->serial = serial;
956 		spin_lock_init(&port->lock);
957 		/* Keep this for private driver use for the moment but
958 		   should probably go away */
959 		INIT_WORK(&port->work, usb_serial_port_work);
960 		serial->port[i] = port;
961 		port->dev.parent = &interface->dev;
962 		port->dev.driver = NULL;
963 		port->dev.bus = &usb_serial_bus_type;
964 		port->dev.release = &usb_serial_port_release;
965 		port->dev.groups = usb_serial_port_groups;
966 		device_initialize(&port->dev);
967 	}
968 
969 	/* set up the endpoint information */
970 	for (i = 0; i < epds->num_bulk_in; ++i) {
971 		retval = setup_port_bulk_in(serial->port[i], epds->bulk_in[i]);
972 		if (retval)
973 			goto err_free_epds;
974 	}
975 
976 	for (i = 0; i < epds->num_bulk_out; ++i) {
977 		retval = setup_port_bulk_out(serial->port[i],
978 				epds->bulk_out[i]);
979 		if (retval)
980 			goto err_free_epds;
981 	}
982 
983 	if (serial->type->read_int_callback) {
984 		for (i = 0; i < epds->num_interrupt_in; ++i) {
985 			retval = setup_port_interrupt_in(serial->port[i],
986 					epds->interrupt_in[i]);
987 			if (retval)
988 				goto err_free_epds;
989 		}
990 	} else if (epds->num_interrupt_in) {
991 		dev_dbg(ddev, "The device claims to support interrupt in transfers, but read_int_callback is not defined\n");
992 	}
993 
994 	if (serial->type->write_int_callback) {
995 		for (i = 0; i < epds->num_interrupt_out; ++i) {
996 			retval = setup_port_interrupt_out(serial->port[i],
997 					epds->interrupt_out[i]);
998 			if (retval)
999 				goto err_free_epds;
1000 		}
1001 	} else if (epds->num_interrupt_out) {
1002 		dev_dbg(ddev, "The device claims to support interrupt out transfers, but write_int_callback is not defined\n");
1003 	}
1004 
1005 	usb_set_intfdata(interface, serial);
1006 
1007 	/* if this device type has an attach function, call it */
1008 	if (type->attach) {
1009 		retval = type->attach(serial);
1010 		if (retval < 0)
1011 			goto err_free_epds;
1012 		serial->attached = 1;
1013 		if (retval > 0) {
1014 			/* quietly accept this device, but don't bind to a
1015 			   serial port as it's about to disappear */
1016 			serial->num_ports = 0;
1017 			goto exit;
1018 		}
1019 	} else {
1020 		serial->attached = 1;
1021 	}
1022 
1023 	retval = allocate_minors(serial, num_ports);
1024 	if (retval) {
1025 		dev_err(ddev, "No more free serial minor numbers\n");
1026 		goto err_free_epds;
1027 	}
1028 
1029 	/* register all of the individual ports with the driver core */
1030 	for (i = 0; i < num_ports; ++i) {
1031 		port = serial->port[i];
1032 		dev_set_name(&port->dev, "ttyUSB%d", port->minor);
1033 		dev_dbg(ddev, "registering %s\n", dev_name(&port->dev));
1034 		device_enable_async_suspend(&port->dev);
1035 
1036 		retval = device_add(&port->dev);
1037 		if (retval)
1038 			dev_err(ddev, "Error registering port device, continuing\n");
1039 	}
1040 
1041 	if (num_ports > 0)
1042 		usb_serial_console_init(serial->port[0]->minor);
1043 exit:
1044 	kfree(epds);
1045 	module_put(type->driver.owner);
1046 	return 0;
1047 
1048 err_free_epds:
1049 	kfree(epds);
1050 err_put_serial:
1051 	usb_serial_put(serial);
1052 err_put_module:
1053 	module_put(type->driver.owner);
1054 
1055 	return retval;
1056 }
1057 
1058 static void usb_serial_disconnect(struct usb_interface *interface)
1059 {
1060 	int i;
1061 	struct usb_serial *serial = usb_get_intfdata(interface);
1062 	struct device *dev = &interface->dev;
1063 	struct usb_serial_port *port;
1064 	struct tty_struct *tty;
1065 
1066 	usb_serial_console_disconnect(serial);
1067 
1068 	mutex_lock(&serial->disc_mutex);
1069 	/* must set a flag, to signal subdrivers */
1070 	serial->disconnected = 1;
1071 	mutex_unlock(&serial->disc_mutex);
1072 
1073 	for (i = 0; i < serial->num_ports; ++i) {
1074 		port = serial->port[i];
1075 		tty = tty_port_tty_get(&port->port);
1076 		if (tty) {
1077 			tty_vhangup(tty);
1078 			tty_kref_put(tty);
1079 		}
1080 		usb_serial_port_poison_urbs(port);
1081 		wake_up_interruptible(&port->port.delta_msr_wait);
1082 		cancel_work_sync(&port->work);
1083 		if (device_is_registered(&port->dev))
1084 			device_del(&port->dev);
1085 	}
1086 	if (serial->type->disconnect)
1087 		serial->type->disconnect(serial);
1088 
1089 	/* let the last holder of this object cause it to be cleaned up */
1090 	usb_serial_put(serial);
1091 	dev_info(dev, "device disconnected\n");
1092 }
1093 
1094 int usb_serial_suspend(struct usb_interface *intf, pm_message_t message)
1095 {
1096 	struct usb_serial *serial = usb_get_intfdata(intf);
1097 	int i, r = 0;
1098 
1099 	serial->suspending = 1;
1100 
1101 	/*
1102 	 * serial->type->suspend() MUST return 0 in system sleep context,
1103 	 * otherwise, the resume callback has to recover device from
1104 	 * previous suspend failure.
1105 	 */
1106 	if (serial->type->suspend) {
1107 		r = serial->type->suspend(serial, message);
1108 		if (r < 0) {
1109 			serial->suspending = 0;
1110 			goto err_out;
1111 		}
1112 	}
1113 
1114 	for (i = 0; i < serial->num_ports; ++i)
1115 		usb_serial_port_poison_urbs(serial->port[i]);
1116 err_out:
1117 	return r;
1118 }
1119 EXPORT_SYMBOL(usb_serial_suspend);
1120 
1121 static void usb_serial_unpoison_port_urbs(struct usb_serial *serial)
1122 {
1123 	int i;
1124 
1125 	for (i = 0; i < serial->num_ports; ++i)
1126 		usb_serial_port_unpoison_urbs(serial->port[i]);
1127 }
1128 
1129 int usb_serial_resume(struct usb_interface *intf)
1130 {
1131 	struct usb_serial *serial = usb_get_intfdata(intf);
1132 	int rv;
1133 
1134 	usb_serial_unpoison_port_urbs(serial);
1135 
1136 	serial->suspending = 0;
1137 	if (serial->type->resume)
1138 		rv = serial->type->resume(serial);
1139 	else
1140 		rv = usb_serial_generic_resume(serial);
1141 
1142 	return rv;
1143 }
1144 EXPORT_SYMBOL(usb_serial_resume);
1145 
1146 static int usb_serial_reset_resume(struct usb_interface *intf)
1147 {
1148 	struct usb_serial *serial = usb_get_intfdata(intf);
1149 	int rv;
1150 
1151 	usb_serial_unpoison_port_urbs(serial);
1152 
1153 	serial->suspending = 0;
1154 	if (serial->type->reset_resume) {
1155 		rv = serial->type->reset_resume(serial);
1156 	} else {
1157 		rv = -EOPNOTSUPP;
1158 		intf->needs_binding = 1;
1159 	}
1160 
1161 	return rv;
1162 }
1163 
1164 static const struct tty_operations serial_ops = {
1165 	.open =			serial_open,
1166 	.close =		serial_close,
1167 	.write =		serial_write,
1168 	.hangup =		serial_hangup,
1169 	.write_room =		serial_write_room,
1170 	.ioctl =		serial_ioctl,
1171 	.set_termios =		serial_set_termios,
1172 	.throttle =		serial_throttle,
1173 	.unthrottle =		serial_unthrottle,
1174 	.break_ctl =		serial_break,
1175 	.chars_in_buffer =	serial_chars_in_buffer,
1176 	.wait_until_sent =	serial_wait_until_sent,
1177 	.tiocmget =		serial_tiocmget,
1178 	.tiocmset =		serial_tiocmset,
1179 	.get_icount =		serial_get_icount,
1180 	.cleanup =		serial_cleanup,
1181 	.install =		serial_install,
1182 	.proc_show =		serial_proc_show,
1183 };
1184 
1185 
1186 struct tty_driver *usb_serial_tty_driver;
1187 
1188 static int __init usb_serial_init(void)
1189 {
1190 	int result;
1191 
1192 	usb_serial_tty_driver = alloc_tty_driver(USB_SERIAL_TTY_MINORS);
1193 	if (!usb_serial_tty_driver)
1194 		return -ENOMEM;
1195 
1196 	/* Initialize our global data */
1197 	result = bus_register(&usb_serial_bus_type);
1198 	if (result) {
1199 		pr_err("%s - registering bus driver failed\n", __func__);
1200 		goto exit_bus;
1201 	}
1202 
1203 	usb_serial_tty_driver->driver_name = "usbserial";
1204 	usb_serial_tty_driver->name = "ttyUSB";
1205 	usb_serial_tty_driver->major = USB_SERIAL_TTY_MAJOR;
1206 	usb_serial_tty_driver->minor_start = 0;
1207 	usb_serial_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
1208 	usb_serial_tty_driver->subtype = SERIAL_TYPE_NORMAL;
1209 	usb_serial_tty_driver->flags = TTY_DRIVER_REAL_RAW |
1210 						TTY_DRIVER_DYNAMIC_DEV;
1211 	usb_serial_tty_driver->init_termios = tty_std_termios;
1212 	usb_serial_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD
1213 							| HUPCL | CLOCAL;
1214 	usb_serial_tty_driver->init_termios.c_ispeed = 9600;
1215 	usb_serial_tty_driver->init_termios.c_ospeed = 9600;
1216 	tty_set_operations(usb_serial_tty_driver, &serial_ops);
1217 	result = tty_register_driver(usb_serial_tty_driver);
1218 	if (result) {
1219 		pr_err("%s - tty_register_driver failed\n", __func__);
1220 		goto exit_reg_driver;
1221 	}
1222 
1223 	/* register the generic driver, if we should */
1224 	result = usb_serial_generic_register();
1225 	if (result < 0) {
1226 		pr_err("%s - registering generic driver failed\n", __func__);
1227 		goto exit_generic;
1228 	}
1229 
1230 	return result;
1231 
1232 exit_generic:
1233 	tty_unregister_driver(usb_serial_tty_driver);
1234 
1235 exit_reg_driver:
1236 	bus_unregister(&usb_serial_bus_type);
1237 
1238 exit_bus:
1239 	pr_err("%s - returning with error %d\n", __func__, result);
1240 	put_tty_driver(usb_serial_tty_driver);
1241 	return result;
1242 }
1243 
1244 
1245 static void __exit usb_serial_exit(void)
1246 {
1247 	usb_serial_console_exit();
1248 
1249 	usb_serial_generic_deregister();
1250 
1251 	tty_unregister_driver(usb_serial_tty_driver);
1252 	put_tty_driver(usb_serial_tty_driver);
1253 	bus_unregister(&usb_serial_bus_type);
1254 	idr_destroy(&serial_minors);
1255 }
1256 
1257 
1258 module_init(usb_serial_init);
1259 module_exit(usb_serial_exit);
1260 
1261 #define set_to_generic_if_null(type, function)				\
1262 	do {								\
1263 		if (!type->function) {					\
1264 			type->function = usb_serial_generic_##function;	\
1265 			pr_debug("%s: using generic " #function	"\n",	\
1266 						type->driver.name);	\
1267 		}							\
1268 	} while (0)
1269 
1270 static void usb_serial_operations_init(struct usb_serial_driver *device)
1271 {
1272 	set_to_generic_if_null(device, open);
1273 	set_to_generic_if_null(device, write);
1274 	set_to_generic_if_null(device, close);
1275 	set_to_generic_if_null(device, write_room);
1276 	set_to_generic_if_null(device, chars_in_buffer);
1277 	if (device->tx_empty)
1278 		set_to_generic_if_null(device, wait_until_sent);
1279 	set_to_generic_if_null(device, read_bulk_callback);
1280 	set_to_generic_if_null(device, write_bulk_callback);
1281 	set_to_generic_if_null(device, process_read_urb);
1282 	set_to_generic_if_null(device, prepare_write_buffer);
1283 }
1284 
1285 static int usb_serial_register(struct usb_serial_driver *driver)
1286 {
1287 	int retval;
1288 
1289 	if (usb_disabled())
1290 		return -ENODEV;
1291 
1292 	if (!driver->description)
1293 		driver->description = driver->driver.name;
1294 	if (!driver->usb_driver) {
1295 		WARN(1, "Serial driver %s has no usb_driver\n",
1296 				driver->description);
1297 		return -EINVAL;
1298 	}
1299 
1300 	usb_serial_operations_init(driver);
1301 
1302 	/* Add this device to our list of devices */
1303 	mutex_lock(&table_lock);
1304 	list_add(&driver->driver_list, &usb_serial_driver_list);
1305 
1306 	retval = usb_serial_bus_register(driver);
1307 	if (retval) {
1308 		pr_err("problem %d when registering driver %s\n", retval, driver->description);
1309 		list_del(&driver->driver_list);
1310 	} else {
1311 		pr_info("USB Serial support registered for %s\n", driver->description);
1312 	}
1313 	mutex_unlock(&table_lock);
1314 	return retval;
1315 }
1316 
1317 static void usb_serial_deregister(struct usb_serial_driver *device)
1318 {
1319 	pr_info("USB Serial deregistering driver %s\n", device->description);
1320 
1321 	mutex_lock(&table_lock);
1322 	list_del(&device->driver_list);
1323 	mutex_unlock(&table_lock);
1324 
1325 	usb_serial_bus_deregister(device);
1326 }
1327 
1328 /**
1329  * usb_serial_register_drivers - register drivers for a usb-serial module
1330  * @serial_drivers: NULL-terminated array of pointers to drivers to be registered
1331  * @name: name of the usb_driver for this set of @serial_drivers
1332  * @id_table: list of all devices this @serial_drivers set binds to
1333  *
1334  * Registers all the drivers in the @serial_drivers array, and dynamically
1335  * creates a struct usb_driver with the name @name and id_table of @id_table.
1336  */
1337 int usb_serial_register_drivers(struct usb_serial_driver *const serial_drivers[],
1338 				const char *name,
1339 				const struct usb_device_id *id_table)
1340 {
1341 	int rc;
1342 	struct usb_driver *udriver;
1343 	struct usb_serial_driver * const *sd;
1344 
1345 	/*
1346 	 * udriver must be registered before any of the serial drivers,
1347 	 * because the store_new_id() routine for the serial drivers (in
1348 	 * bus.c) probes udriver.
1349 	 *
1350 	 * Performance hack: We don't want udriver to be probed until
1351 	 * the serial drivers are registered, because the probe would
1352 	 * simply fail for lack of a matching serial driver.
1353 	 * So we leave udriver's id_table set to NULL until we are all set.
1354 	 *
1355 	 * Suspend/resume support is implemented in the usb-serial core,
1356 	 * so fill in the PM-related fields in udriver.
1357 	 */
1358 	udriver = kzalloc(sizeof(*udriver), GFP_KERNEL);
1359 	if (!udriver)
1360 		return -ENOMEM;
1361 
1362 	udriver->name = name;
1363 	udriver->no_dynamic_id = 1;
1364 	udriver->supports_autosuspend = 1;
1365 	udriver->suspend = usb_serial_suspend;
1366 	udriver->resume = usb_serial_resume;
1367 	udriver->probe = usb_serial_probe;
1368 	udriver->disconnect = usb_serial_disconnect;
1369 
1370 	/* we only set the reset_resume field if the serial_driver has one */
1371 	for (sd = serial_drivers; *sd; ++sd) {
1372 		if ((*sd)->reset_resume) {
1373 			udriver->reset_resume = usb_serial_reset_resume;
1374 			break;
1375 		}
1376 	}
1377 
1378 	rc = usb_register(udriver);
1379 	if (rc)
1380 		goto failed_usb_register;
1381 
1382 	for (sd = serial_drivers; *sd; ++sd) {
1383 		(*sd)->usb_driver = udriver;
1384 		rc = usb_serial_register(*sd);
1385 		if (rc)
1386 			goto failed;
1387 	}
1388 
1389 	/* Now set udriver's id_table and look for matches */
1390 	udriver->id_table = id_table;
1391 	rc = driver_attach(&udriver->drvwrap.driver);
1392 	return 0;
1393 
1394  failed:
1395 	while (sd-- > serial_drivers)
1396 		usb_serial_deregister(*sd);
1397 	usb_deregister(udriver);
1398 failed_usb_register:
1399 	kfree(udriver);
1400 	return rc;
1401 }
1402 EXPORT_SYMBOL_GPL(usb_serial_register_drivers);
1403 
1404 /**
1405  * usb_serial_deregister_drivers - deregister drivers for a usb-serial module
1406  * @serial_drivers: NULL-terminated array of pointers to drivers to be deregistered
1407  *
1408  * Deregisters all the drivers in the @serial_drivers array and deregisters and
1409  * frees the struct usb_driver that was created by the call to
1410  * usb_serial_register_drivers().
1411  */
1412 void usb_serial_deregister_drivers(struct usb_serial_driver *const serial_drivers[])
1413 {
1414 	struct usb_driver *udriver = (*serial_drivers)->usb_driver;
1415 
1416 	for (; *serial_drivers; ++serial_drivers)
1417 		usb_serial_deregister(*serial_drivers);
1418 	usb_deregister(udriver);
1419 	kfree(udriver);
1420 }
1421 EXPORT_SYMBOL_GPL(usb_serial_deregister_drivers);
1422 
1423 MODULE_AUTHOR(DRIVER_AUTHOR);
1424 MODULE_DESCRIPTION(DRIVER_DESC);
1425 MODULE_LICENSE("GPL v2");
1426