xref: /linux/drivers/usb/serial/usb-serial.c (revision 3932b9ca55b0be314a36d3e84faff3e823c081f5)
1 /*
2  * USB Serial Converter driver
3  *
4  * Copyright (C) 2009 - 2013 Johan Hovold (jhovold@gmail.com)
5  * Copyright (C) 1999 - 2012 Greg Kroah-Hartman (greg@kroah.com)
6  * Copyright (C) 2000 Peter Berger (pberger@brimson.com)
7  * Copyright (C) 2000 Al Borchers (borchers@steinerpoint.com)
8  *
9  *	This program is free software; you can redistribute it and/or
10  *	modify it under the terms of the GNU General Public License version
11  *	2 as published by the Free Software Foundation.
12  *
13  * This driver was originally based on the ACM driver by Armin Fuerst (which was
14  * based on a driver by Brad Keryan)
15  *
16  * See Documentation/usb/usb-serial.txt for more information on using this
17  * driver
18  */
19 
20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21 
22 #include <linux/kernel.h>
23 #include <linux/errno.h>
24 #include <linux/init.h>
25 #include <linux/slab.h>
26 #include <linux/tty.h>
27 #include <linux/tty_driver.h>
28 #include <linux/tty_flip.h>
29 #include <linux/module.h>
30 #include <linux/moduleparam.h>
31 #include <linux/seq_file.h>
32 #include <linux/spinlock.h>
33 #include <linux/mutex.h>
34 #include <linux/list.h>
35 #include <linux/uaccess.h>
36 #include <linux/serial.h>
37 #include <linux/usb.h>
38 #include <linux/usb/serial.h>
39 #include <linux/kfifo.h>
40 #include <linux/idr.h>
41 #include "pl2303.h"
42 
43 #define DRIVER_AUTHOR "Greg Kroah-Hartman <gregkh@linuxfoundation.org>"
44 #define DRIVER_DESC "USB Serial Driver core"
45 
46 #define USB_SERIAL_TTY_MAJOR	188
47 #define USB_SERIAL_TTY_MINORS	512	/* should be enough for a while */
48 
49 /* There is no MODULE_DEVICE_TABLE for usbserial.c.  Instead
50    the MODULE_DEVICE_TABLE declarations in each serial driver
51    cause the "hotplug" program to pull in whatever module is necessary
52    via modprobe, and modprobe will load usbserial because the serial
53    drivers depend on it.
54 */
55 
56 static DEFINE_IDR(serial_minors);
57 static DEFINE_MUTEX(table_lock);
58 static LIST_HEAD(usb_serial_driver_list);
59 
60 /*
61  * Look up the serial port structure.  If it is found and it hasn't been
62  * disconnected, return with the parent usb_serial structure's disc_mutex held
63  * and its refcount incremented.  Otherwise return NULL.
64  */
65 struct usb_serial_port *usb_serial_port_get_by_minor(unsigned minor)
66 {
67 	struct usb_serial *serial;
68 	struct usb_serial_port *port;
69 
70 	mutex_lock(&table_lock);
71 	port = idr_find(&serial_minors, minor);
72 	if (!port)
73 		goto exit;
74 
75 	serial = port->serial;
76 	mutex_lock(&serial->disc_mutex);
77 	if (serial->disconnected) {
78 		mutex_unlock(&serial->disc_mutex);
79 		port = NULL;
80 	} else {
81 		kref_get(&serial->kref);
82 	}
83 exit:
84 	mutex_unlock(&table_lock);
85 	return port;
86 }
87 
88 static int allocate_minors(struct usb_serial *serial, int num_ports)
89 {
90 	struct usb_serial_port *port;
91 	unsigned int i, j;
92 	int minor;
93 
94 	dev_dbg(&serial->interface->dev, "%s %d\n", __func__, num_ports);
95 
96 	mutex_lock(&table_lock);
97 	for (i = 0; i < num_ports; ++i) {
98 		port = serial->port[i];
99 		minor = idr_alloc(&serial_minors, port, 0, 0, GFP_KERNEL);
100 		if (minor < 0)
101 			goto error;
102 		port->minor = minor;
103 		port->port_number = i;
104 	}
105 	serial->minors_reserved = 1;
106 	mutex_unlock(&table_lock);
107 	return 0;
108 error:
109 	/* unwind the already allocated minors */
110 	for (j = 0; j < i; ++j)
111 		idr_remove(&serial_minors, serial->port[j]->minor);
112 	mutex_unlock(&table_lock);
113 	return minor;
114 }
115 
116 static void release_minors(struct usb_serial *serial)
117 {
118 	int i;
119 
120 	mutex_lock(&table_lock);
121 	for (i = 0; i < serial->num_ports; ++i)
122 		idr_remove(&serial_minors, serial->port[i]->minor);
123 	mutex_unlock(&table_lock);
124 	serial->minors_reserved = 0;
125 }
126 
127 static void destroy_serial(struct kref *kref)
128 {
129 	struct usb_serial *serial;
130 	struct usb_serial_port *port;
131 	int i;
132 
133 	serial = to_usb_serial(kref);
134 
135 	/* return the minor range that this device had */
136 	if (serial->minors_reserved)
137 		release_minors(serial);
138 
139 	if (serial->attached && serial->type->release)
140 		serial->type->release(serial);
141 
142 	/* Now that nothing is using the ports, they can be freed */
143 	for (i = 0; i < serial->num_port_pointers; ++i) {
144 		port = serial->port[i];
145 		if (port) {
146 			port->serial = NULL;
147 			put_device(&port->dev);
148 		}
149 	}
150 
151 	usb_put_intf(serial->interface);
152 	usb_put_dev(serial->dev);
153 	kfree(serial);
154 }
155 
156 void usb_serial_put(struct usb_serial *serial)
157 {
158 	kref_put(&serial->kref, destroy_serial);
159 }
160 
161 /*****************************************************************************
162  * Driver tty interface functions
163  *****************************************************************************/
164 
165 /**
166  * serial_install - install tty
167  * @driver: the driver (USB in our case)
168  * @tty: the tty being created
169  *
170  * Create the termios objects for this tty.  We use the default
171  * USB serial settings but permit them to be overridden by
172  * serial->type->init_termios.
173  *
174  * This is the first place a new tty gets used.  Hence this is where we
175  * acquire references to the usb_serial structure and the driver module,
176  * where we store a pointer to the port, and where we do an autoresume.
177  * All these actions are reversed in serial_cleanup().
178  */
179 static int serial_install(struct tty_driver *driver, struct tty_struct *tty)
180 {
181 	int idx = tty->index;
182 	struct usb_serial *serial;
183 	struct usb_serial_port *port;
184 	int retval = -ENODEV;
185 
186 	port = usb_serial_port_get_by_minor(idx);
187 	if (!port)
188 		return retval;
189 
190 	serial = port->serial;
191 	if (!try_module_get(serial->type->driver.owner))
192 		goto error_module_get;
193 
194 	retval = usb_autopm_get_interface(serial->interface);
195 	if (retval)
196 		goto error_get_interface;
197 
198 	retval = tty_port_install(&port->port, driver, tty);
199 	if (retval)
200 		goto error_init_termios;
201 
202 	mutex_unlock(&serial->disc_mutex);
203 
204 	/* allow the driver to update the settings */
205 	if (serial->type->init_termios)
206 		serial->type->init_termios(tty);
207 
208 	tty->driver_data = port;
209 
210 	return retval;
211 
212  error_init_termios:
213 	usb_autopm_put_interface(serial->interface);
214  error_get_interface:
215 	module_put(serial->type->driver.owner);
216  error_module_get:
217 	usb_serial_put(serial);
218 	mutex_unlock(&serial->disc_mutex);
219 	return retval;
220 }
221 
222 static int serial_port_activate(struct tty_port *tport, struct tty_struct *tty)
223 {
224 	struct usb_serial_port *port =
225 		container_of(tport, struct usb_serial_port, port);
226 	struct usb_serial *serial = port->serial;
227 	int retval;
228 
229 	mutex_lock(&serial->disc_mutex);
230 	if (serial->disconnected)
231 		retval = -ENODEV;
232 	else
233 		retval = port->serial->type->open(tty, port);
234 	mutex_unlock(&serial->disc_mutex);
235 
236 	if (retval < 0)
237 		retval = usb_translate_errors(retval);
238 
239 	return retval;
240 }
241 
242 static int serial_open(struct tty_struct *tty, struct file *filp)
243 {
244 	struct usb_serial_port *port = tty->driver_data;
245 
246 	dev_dbg(tty->dev, "%s\n", __func__);
247 
248 	return tty_port_open(&port->port, tty, filp);
249 }
250 
251 /**
252  * serial_port_shutdown - shut down hardware
253  * @tport: tty port to shut down
254  *
255  * Shut down a USB serial port. Serialized against activate by the
256  * tport mutex and kept to matching open/close pairs
257  * of calls by the ASYNCB_INITIALIZED flag.
258  *
259  * Not called if tty is console.
260  */
261 static void serial_port_shutdown(struct tty_port *tport)
262 {
263 	struct usb_serial_port *port =
264 		container_of(tport, struct usb_serial_port, port);
265 	struct usb_serial_driver *drv = port->serial->type;
266 
267 	if (drv->close)
268 		drv->close(port);
269 }
270 
271 static void serial_hangup(struct tty_struct *tty)
272 {
273 	struct usb_serial_port *port = tty->driver_data;
274 
275 	dev_dbg(tty->dev, "%s\n", __func__);
276 
277 	tty_port_hangup(&port->port);
278 }
279 
280 static void serial_close(struct tty_struct *tty, struct file *filp)
281 {
282 	struct usb_serial_port *port = tty->driver_data;
283 
284 	dev_dbg(tty->dev, "%s\n", __func__);
285 
286 	tty_port_close(&port->port, tty, filp);
287 }
288 
289 /**
290  * serial_cleanup - free resources post close/hangup
291  * @port: port to free up
292  *
293  * Do the resource freeing and refcount dropping for the port.
294  * Avoid freeing the console.
295  *
296  * Called asynchronously after the last tty kref is dropped.
297  */
298 static void serial_cleanup(struct tty_struct *tty)
299 {
300 	struct usb_serial_port *port = tty->driver_data;
301 	struct usb_serial *serial;
302 	struct module *owner;
303 
304 	dev_dbg(tty->dev, "%s\n", __func__);
305 
306 	/* The console is magical.  Do not hang up the console hardware
307 	 * or there will be tears.
308 	 */
309 	if (port->port.console)
310 		return;
311 
312 	tty->driver_data = NULL;
313 
314 	serial = port->serial;
315 	owner = serial->type->driver.owner;
316 
317 	mutex_lock(&serial->disc_mutex);
318 	if (!serial->disconnected)
319 		usb_autopm_put_interface(serial->interface);
320 	mutex_unlock(&serial->disc_mutex);
321 
322 	usb_serial_put(serial);
323 	module_put(owner);
324 }
325 
326 static int serial_write(struct tty_struct *tty, const unsigned char *buf,
327 								int count)
328 {
329 	struct usb_serial_port *port = tty->driver_data;
330 	int retval = -ENODEV;
331 
332 	if (port->serial->dev->state == USB_STATE_NOTATTACHED)
333 		goto exit;
334 
335 	dev_dbg(tty->dev, "%s - %d byte(s)\n", __func__, count);
336 
337 	retval = port->serial->type->write(tty, port, buf, count);
338 	if (retval < 0)
339 		retval = usb_translate_errors(retval);
340 exit:
341 	return retval;
342 }
343 
344 static int serial_write_room(struct tty_struct *tty)
345 {
346 	struct usb_serial_port *port = tty->driver_data;
347 
348 	dev_dbg(tty->dev, "%s\n", __func__);
349 
350 	return port->serial->type->write_room(tty);
351 }
352 
353 static int serial_chars_in_buffer(struct tty_struct *tty)
354 {
355 	struct usb_serial_port *port = tty->driver_data;
356 	struct usb_serial *serial = port->serial;
357 
358 	dev_dbg(tty->dev, "%s\n", __func__);
359 
360 	if (serial->disconnected)
361 		return 0;
362 
363 	return serial->type->chars_in_buffer(tty);
364 }
365 
366 static void serial_wait_until_sent(struct tty_struct *tty, int timeout)
367 {
368 	struct usb_serial_port *port = tty->driver_data;
369 	struct usb_serial *serial = port->serial;
370 
371 	dev_dbg(tty->dev, "%s\n", __func__);
372 
373 	if (!port->serial->type->wait_until_sent)
374 		return;
375 
376 	mutex_lock(&serial->disc_mutex);
377 	if (!serial->disconnected)
378 		port->serial->type->wait_until_sent(tty, timeout);
379 	mutex_unlock(&serial->disc_mutex);
380 }
381 
382 static void serial_throttle(struct tty_struct *tty)
383 {
384 	struct usb_serial_port *port = tty->driver_data;
385 
386 	dev_dbg(tty->dev, "%s\n", __func__);
387 
388 	if (port->serial->type->throttle)
389 		port->serial->type->throttle(tty);
390 }
391 
392 static void serial_unthrottle(struct tty_struct *tty)
393 {
394 	struct usb_serial_port *port = tty->driver_data;
395 
396 	dev_dbg(tty->dev, "%s\n", __func__);
397 
398 	if (port->serial->type->unthrottle)
399 		port->serial->type->unthrottle(tty);
400 }
401 
402 static int serial_ioctl(struct tty_struct *tty,
403 					unsigned int cmd, unsigned long arg)
404 {
405 	struct usb_serial_port *port = tty->driver_data;
406 	int retval = -ENOIOCTLCMD;
407 
408 	dev_dbg(tty->dev, "%s - cmd 0x%04x\n", __func__, cmd);
409 
410 	switch (cmd) {
411 	case TIOCMIWAIT:
412 		if (port->serial->type->tiocmiwait)
413 			retval = port->serial->type->tiocmiwait(tty, arg);
414 		break;
415 	default:
416 		if (port->serial->type->ioctl)
417 			retval = port->serial->type->ioctl(tty, cmd, arg);
418 	}
419 
420 	return retval;
421 }
422 
423 static void serial_set_termios(struct tty_struct *tty, struct ktermios *old)
424 {
425 	struct usb_serial_port *port = tty->driver_data;
426 
427 	dev_dbg(tty->dev, "%s\n", __func__);
428 
429 	if (port->serial->type->set_termios)
430 		port->serial->type->set_termios(tty, port, old);
431 	else
432 		tty_termios_copy_hw(&tty->termios, old);
433 }
434 
435 static int serial_break(struct tty_struct *tty, int break_state)
436 {
437 	struct usb_serial_port *port = tty->driver_data;
438 
439 	dev_dbg(tty->dev, "%s\n", __func__);
440 
441 	if (port->serial->type->break_ctl)
442 		port->serial->type->break_ctl(tty, break_state);
443 
444 	return 0;
445 }
446 
447 static int serial_proc_show(struct seq_file *m, void *v)
448 {
449 	struct usb_serial *serial;
450 	struct usb_serial_port *port;
451 	int i;
452 	char tmp[40];
453 
454 	seq_puts(m, "usbserinfo:1.0 driver:2.0\n");
455 	for (i = 0; i < USB_SERIAL_TTY_MINORS; ++i) {
456 		port = usb_serial_port_get_by_minor(i);
457 		if (port == NULL)
458 			continue;
459 		serial = port->serial;
460 
461 		seq_printf(m, "%d:", i);
462 		if (serial->type->driver.owner)
463 			seq_printf(m, " module:%s",
464 				module_name(serial->type->driver.owner));
465 		seq_printf(m, " name:\"%s\"",
466 				serial->type->description);
467 		seq_printf(m, " vendor:%04x product:%04x",
468 			le16_to_cpu(serial->dev->descriptor.idVendor),
469 			le16_to_cpu(serial->dev->descriptor.idProduct));
470 		seq_printf(m, " num_ports:%d", serial->num_ports);
471 		seq_printf(m, " port:%d", port->port_number);
472 		usb_make_path(serial->dev, tmp, sizeof(tmp));
473 		seq_printf(m, " path:%s", tmp);
474 
475 		seq_putc(m, '\n');
476 		usb_serial_put(serial);
477 		mutex_unlock(&serial->disc_mutex);
478 	}
479 	return 0;
480 }
481 
482 static int serial_proc_open(struct inode *inode, struct file *file)
483 {
484 	return single_open(file, serial_proc_show, NULL);
485 }
486 
487 static const struct file_operations serial_proc_fops = {
488 	.owner		= THIS_MODULE,
489 	.open		= serial_proc_open,
490 	.read		= seq_read,
491 	.llseek		= seq_lseek,
492 	.release	= single_release,
493 };
494 
495 static int serial_tiocmget(struct tty_struct *tty)
496 {
497 	struct usb_serial_port *port = tty->driver_data;
498 
499 	dev_dbg(tty->dev, "%s\n", __func__);
500 
501 	if (port->serial->type->tiocmget)
502 		return port->serial->type->tiocmget(tty);
503 	return -EINVAL;
504 }
505 
506 static int serial_tiocmset(struct tty_struct *tty,
507 			    unsigned int set, unsigned int clear)
508 {
509 	struct usb_serial_port *port = tty->driver_data;
510 
511 	dev_dbg(tty->dev, "%s\n", __func__);
512 
513 	if (port->serial->type->tiocmset)
514 		return port->serial->type->tiocmset(tty, set, clear);
515 	return -EINVAL;
516 }
517 
518 static int serial_get_icount(struct tty_struct *tty,
519 				struct serial_icounter_struct *icount)
520 {
521 	struct usb_serial_port *port = tty->driver_data;
522 
523 	dev_dbg(tty->dev, "%s\n", __func__);
524 
525 	if (port->serial->type->get_icount)
526 		return port->serial->type->get_icount(tty, icount);
527 	return -EINVAL;
528 }
529 
530 /*
531  * We would be calling tty_wakeup here, but unfortunately some line
532  * disciplines have an annoying habit of calling tty->write from
533  * the write wakeup callback (e.g. n_hdlc.c).
534  */
535 void usb_serial_port_softint(struct usb_serial_port *port)
536 {
537 	schedule_work(&port->work);
538 }
539 EXPORT_SYMBOL_GPL(usb_serial_port_softint);
540 
541 static void usb_serial_port_work(struct work_struct *work)
542 {
543 	struct usb_serial_port *port =
544 		container_of(work, struct usb_serial_port, work);
545 
546 	tty_port_tty_wakeup(&port->port);
547 }
548 
549 static void usb_serial_port_poison_urbs(struct usb_serial_port *port)
550 {
551 	int i;
552 
553 	for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
554 		usb_poison_urb(port->read_urbs[i]);
555 	for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
556 		usb_poison_urb(port->write_urbs[i]);
557 
558 	usb_poison_urb(port->interrupt_in_urb);
559 	usb_poison_urb(port->interrupt_out_urb);
560 }
561 
562 static void usb_serial_port_unpoison_urbs(struct usb_serial_port *port)
563 {
564 	int i;
565 
566 	for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
567 		usb_unpoison_urb(port->read_urbs[i]);
568 	for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
569 		usb_unpoison_urb(port->write_urbs[i]);
570 
571 	usb_unpoison_urb(port->interrupt_in_urb);
572 	usb_unpoison_urb(port->interrupt_out_urb);
573 }
574 
575 static void usb_serial_port_release(struct device *dev)
576 {
577 	struct usb_serial_port *port = to_usb_serial_port(dev);
578 	int i;
579 
580 	dev_dbg(dev, "%s\n", __func__);
581 
582 	usb_free_urb(port->interrupt_in_urb);
583 	usb_free_urb(port->interrupt_out_urb);
584 	for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
585 		usb_free_urb(port->read_urbs[i]);
586 		kfree(port->bulk_in_buffers[i]);
587 	}
588 	for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) {
589 		usb_free_urb(port->write_urbs[i]);
590 		kfree(port->bulk_out_buffers[i]);
591 	}
592 	kfifo_free(&port->write_fifo);
593 	kfree(port->interrupt_in_buffer);
594 	kfree(port->interrupt_out_buffer);
595 	tty_port_destroy(&port->port);
596 	kfree(port);
597 }
598 
599 static struct usb_serial *create_serial(struct usb_device *dev,
600 					struct usb_interface *interface,
601 					struct usb_serial_driver *driver)
602 {
603 	struct usb_serial *serial;
604 
605 	serial = kzalloc(sizeof(*serial), GFP_KERNEL);
606 	if (!serial)
607 		return NULL;
608 	serial->dev = usb_get_dev(dev);
609 	serial->type = driver;
610 	serial->interface = usb_get_intf(interface);
611 	kref_init(&serial->kref);
612 	mutex_init(&serial->disc_mutex);
613 	serial->minors_reserved = 0;
614 
615 	return serial;
616 }
617 
618 static const struct usb_device_id *match_dynamic_id(struct usb_interface *intf,
619 					    struct usb_serial_driver *drv)
620 {
621 	struct usb_dynid *dynid;
622 
623 	spin_lock(&drv->dynids.lock);
624 	list_for_each_entry(dynid, &drv->dynids.list, node) {
625 		if (usb_match_one_id(intf, &dynid->id)) {
626 			spin_unlock(&drv->dynids.lock);
627 			return &dynid->id;
628 		}
629 	}
630 	spin_unlock(&drv->dynids.lock);
631 	return NULL;
632 }
633 
634 static const struct usb_device_id *get_iface_id(struct usb_serial_driver *drv,
635 						struct usb_interface *intf)
636 {
637 	const struct usb_device_id *id;
638 
639 	id = usb_match_id(intf, drv->id_table);
640 	if (id) {
641 		dev_dbg(&intf->dev, "static descriptor matches\n");
642 		goto exit;
643 	}
644 	id = match_dynamic_id(intf, drv);
645 	if (id)
646 		dev_dbg(&intf->dev, "dynamic descriptor matches\n");
647 exit:
648 	return id;
649 }
650 
651 /* Caller must hold table_lock */
652 static struct usb_serial_driver *search_serial_device(
653 					struct usb_interface *iface)
654 {
655 	const struct usb_device_id *id = NULL;
656 	struct usb_serial_driver *drv;
657 	struct usb_driver *driver = to_usb_driver(iface->dev.driver);
658 
659 	/* Check if the usb id matches a known device */
660 	list_for_each_entry(drv, &usb_serial_driver_list, driver_list) {
661 		if (drv->usb_driver == driver)
662 			id = get_iface_id(drv, iface);
663 		if (id)
664 			return drv;
665 	}
666 
667 	return NULL;
668 }
669 
670 static int serial_port_carrier_raised(struct tty_port *port)
671 {
672 	struct usb_serial_port *p = container_of(port, struct usb_serial_port, port);
673 	struct usb_serial_driver *drv = p->serial->type;
674 
675 	if (drv->carrier_raised)
676 		return drv->carrier_raised(p);
677 	/* No carrier control - don't block */
678 	return 1;
679 }
680 
681 static void serial_port_dtr_rts(struct tty_port *port, int on)
682 {
683 	struct usb_serial_port *p = container_of(port, struct usb_serial_port, port);
684 	struct usb_serial_driver *drv = p->serial->type;
685 
686 	if (drv->dtr_rts)
687 		drv->dtr_rts(p, on);
688 }
689 
690 static const struct tty_port_operations serial_port_ops = {
691 	.carrier_raised		= serial_port_carrier_raised,
692 	.dtr_rts		= serial_port_dtr_rts,
693 	.activate		= serial_port_activate,
694 	.shutdown		= serial_port_shutdown,
695 };
696 
697 static int usb_serial_probe(struct usb_interface *interface,
698 			       const struct usb_device_id *id)
699 {
700 	struct device *ddev = &interface->dev;
701 	struct usb_device *dev = interface_to_usbdev(interface);
702 	struct usb_serial *serial = NULL;
703 	struct usb_serial_port *port;
704 	struct usb_host_interface *iface_desc;
705 	struct usb_endpoint_descriptor *endpoint;
706 	struct usb_endpoint_descriptor *interrupt_in_endpoint[MAX_NUM_PORTS];
707 	struct usb_endpoint_descriptor *interrupt_out_endpoint[MAX_NUM_PORTS];
708 	struct usb_endpoint_descriptor *bulk_in_endpoint[MAX_NUM_PORTS];
709 	struct usb_endpoint_descriptor *bulk_out_endpoint[MAX_NUM_PORTS];
710 	struct usb_serial_driver *type = NULL;
711 	int retval;
712 	int buffer_size;
713 	int i;
714 	int j;
715 	int num_interrupt_in = 0;
716 	int num_interrupt_out = 0;
717 	int num_bulk_in = 0;
718 	int num_bulk_out = 0;
719 	int num_ports = 0;
720 	int max_endpoints;
721 
722 	mutex_lock(&table_lock);
723 	type = search_serial_device(interface);
724 	if (!type) {
725 		mutex_unlock(&table_lock);
726 		dev_dbg(ddev, "none matched\n");
727 		return -ENODEV;
728 	}
729 
730 	if (!try_module_get(type->driver.owner)) {
731 		mutex_unlock(&table_lock);
732 		dev_err(ddev, "module get failed, exiting\n");
733 		return -EIO;
734 	}
735 	mutex_unlock(&table_lock);
736 
737 	serial = create_serial(dev, interface, type);
738 	if (!serial) {
739 		module_put(type->driver.owner);
740 		return -ENOMEM;
741 	}
742 
743 	/* if this device type has a probe function, call it */
744 	if (type->probe) {
745 		const struct usb_device_id *id;
746 
747 		id = get_iface_id(type, interface);
748 		retval = type->probe(serial, id);
749 
750 		if (retval) {
751 			dev_dbg(ddev, "sub driver rejected device\n");
752 			usb_serial_put(serial);
753 			module_put(type->driver.owner);
754 			return retval;
755 		}
756 	}
757 
758 	/* descriptor matches, let's find the endpoints needed */
759 	/* check out the endpoints */
760 	iface_desc = interface->cur_altsetting;
761 	for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
762 		endpoint = &iface_desc->endpoint[i].desc;
763 
764 		if (usb_endpoint_is_bulk_in(endpoint)) {
765 			/* we found a bulk in endpoint */
766 			dev_dbg(ddev, "found bulk in on endpoint %d\n", i);
767 			if (num_bulk_in < MAX_NUM_PORTS) {
768 				bulk_in_endpoint[num_bulk_in] = endpoint;
769 				++num_bulk_in;
770 			}
771 		}
772 
773 		if (usb_endpoint_is_bulk_out(endpoint)) {
774 			/* we found a bulk out endpoint */
775 			dev_dbg(ddev, "found bulk out on endpoint %d\n", i);
776 			if (num_bulk_out < MAX_NUM_PORTS) {
777 				bulk_out_endpoint[num_bulk_out] = endpoint;
778 				++num_bulk_out;
779 			}
780 		}
781 
782 		if (usb_endpoint_is_int_in(endpoint)) {
783 			/* we found a interrupt in endpoint */
784 			dev_dbg(ddev, "found interrupt in on endpoint %d\n", i);
785 			if (num_interrupt_in < MAX_NUM_PORTS) {
786 				interrupt_in_endpoint[num_interrupt_in] =
787 						endpoint;
788 				++num_interrupt_in;
789 			}
790 		}
791 
792 		if (usb_endpoint_is_int_out(endpoint)) {
793 			/* we found an interrupt out endpoint */
794 			dev_dbg(ddev, "found interrupt out on endpoint %d\n", i);
795 			if (num_interrupt_out < MAX_NUM_PORTS) {
796 				interrupt_out_endpoint[num_interrupt_out] =
797 						endpoint;
798 				++num_interrupt_out;
799 			}
800 		}
801 	}
802 
803 #if defined(CONFIG_USB_SERIAL_PL2303) || defined(CONFIG_USB_SERIAL_PL2303_MODULE)
804 	/* BEGIN HORRIBLE HACK FOR PL2303 */
805 	/* this is needed due to the looney way its endpoints are set up */
806 	if (((le16_to_cpu(dev->descriptor.idVendor) == PL2303_VENDOR_ID) &&
807 	     (le16_to_cpu(dev->descriptor.idProduct) == PL2303_PRODUCT_ID)) ||
808 	    ((le16_to_cpu(dev->descriptor.idVendor) == ATEN_VENDOR_ID) &&
809 	     (le16_to_cpu(dev->descriptor.idProduct) == ATEN_PRODUCT_ID)) ||
810 	    ((le16_to_cpu(dev->descriptor.idVendor) == ALCOR_VENDOR_ID) &&
811 	     (le16_to_cpu(dev->descriptor.idProduct) == ALCOR_PRODUCT_ID)) ||
812 	    ((le16_to_cpu(dev->descriptor.idVendor) == SIEMENS_VENDOR_ID) &&
813 	     (le16_to_cpu(dev->descriptor.idProduct) == SIEMENS_PRODUCT_ID_EF81))) {
814 		if (interface != dev->actconfig->interface[0]) {
815 			/* check out the endpoints of the other interface*/
816 			iface_desc = dev->actconfig->interface[0]->cur_altsetting;
817 			for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
818 				endpoint = &iface_desc->endpoint[i].desc;
819 				if (usb_endpoint_is_int_in(endpoint)) {
820 					/* we found a interrupt in endpoint */
821 					dev_dbg(ddev, "found interrupt in for Prolific device on separate interface\n");
822 					if (num_interrupt_in < MAX_NUM_PORTS) {
823 						interrupt_in_endpoint[num_interrupt_in] = endpoint;
824 						++num_interrupt_in;
825 					}
826 				}
827 			}
828 		}
829 
830 		/* Now make sure the PL-2303 is configured correctly.
831 		 * If not, give up now and hope this hack will work
832 		 * properly during a later invocation of usb_serial_probe
833 		 */
834 		if (num_bulk_in == 0 || num_bulk_out == 0) {
835 			dev_info(ddev, "PL-2303 hack: descriptors matched but endpoints did not\n");
836 			usb_serial_put(serial);
837 			module_put(type->driver.owner);
838 			return -ENODEV;
839 		}
840 	}
841 	/* END HORRIBLE HACK FOR PL2303 */
842 #endif
843 
844 #ifdef CONFIG_USB_SERIAL_GENERIC
845 	if (type == &usb_serial_generic_device) {
846 		num_ports = num_bulk_out;
847 		if (num_ports == 0) {
848 			dev_err(ddev, "Generic device with no bulk out, not allowed.\n");
849 			usb_serial_put(serial);
850 			module_put(type->driver.owner);
851 			return -EIO;
852 		}
853 		dev_info(ddev, "The \"generic\" usb-serial driver is only for testing and one-off prototypes.\n");
854 		dev_info(ddev, "Tell linux-usb@vger.kernel.org to add your device to a proper driver.\n");
855 	}
856 #endif
857 	if (!num_ports) {
858 		/* if this device type has a calc_num_ports function, call it */
859 		if (type->calc_num_ports)
860 			num_ports = type->calc_num_ports(serial);
861 		if (!num_ports)
862 			num_ports = type->num_ports;
863 	}
864 
865 	if (num_ports > MAX_NUM_PORTS) {
866 		dev_warn(ddev, "too many ports requested: %d\n", num_ports);
867 		num_ports = MAX_NUM_PORTS;
868 	}
869 
870 	serial->num_ports = num_ports;
871 	serial->num_bulk_in = num_bulk_in;
872 	serial->num_bulk_out = num_bulk_out;
873 	serial->num_interrupt_in = num_interrupt_in;
874 	serial->num_interrupt_out = num_interrupt_out;
875 
876 	/* found all that we need */
877 	dev_info(ddev, "%s converter detected\n", type->description);
878 
879 	/* create our ports, we need as many as the max endpoints */
880 	/* we don't use num_ports here because some devices have more
881 	   endpoint pairs than ports */
882 	max_endpoints = max(num_bulk_in, num_bulk_out);
883 	max_endpoints = max(max_endpoints, num_interrupt_in);
884 	max_endpoints = max(max_endpoints, num_interrupt_out);
885 	max_endpoints = max(max_endpoints, (int)serial->num_ports);
886 	serial->num_port_pointers = max_endpoints;
887 
888 	dev_dbg(ddev, "setting up %d port structure(s)\n", max_endpoints);
889 	for (i = 0; i < max_endpoints; ++i) {
890 		port = kzalloc(sizeof(struct usb_serial_port), GFP_KERNEL);
891 		if (!port)
892 			goto probe_error;
893 		tty_port_init(&port->port);
894 		port->port.ops = &serial_port_ops;
895 		port->serial = serial;
896 		spin_lock_init(&port->lock);
897 		/* Keep this for private driver use for the moment but
898 		   should probably go away */
899 		INIT_WORK(&port->work, usb_serial_port_work);
900 		serial->port[i] = port;
901 		port->dev.parent = &interface->dev;
902 		port->dev.driver = NULL;
903 		port->dev.bus = &usb_serial_bus_type;
904 		port->dev.release = &usb_serial_port_release;
905 		device_initialize(&port->dev);
906 	}
907 
908 	/* set up the endpoint information */
909 	for (i = 0; i < num_bulk_in; ++i) {
910 		endpoint = bulk_in_endpoint[i];
911 		port = serial->port[i];
912 		buffer_size = max_t(int, serial->type->bulk_in_size,
913 				usb_endpoint_maxp(endpoint));
914 		port->bulk_in_size = buffer_size;
915 		port->bulk_in_endpointAddress = endpoint->bEndpointAddress;
916 
917 		for (j = 0; j < ARRAY_SIZE(port->read_urbs); ++j) {
918 			set_bit(j, &port->read_urbs_free);
919 			port->read_urbs[j] = usb_alloc_urb(0, GFP_KERNEL);
920 			if (!port->read_urbs[j])
921 				goto probe_error;
922 			port->bulk_in_buffers[j] = kmalloc(buffer_size,
923 								GFP_KERNEL);
924 			if (!port->bulk_in_buffers[j])
925 				goto probe_error;
926 			usb_fill_bulk_urb(port->read_urbs[j], dev,
927 					usb_rcvbulkpipe(dev,
928 						endpoint->bEndpointAddress),
929 					port->bulk_in_buffers[j], buffer_size,
930 					serial->type->read_bulk_callback,
931 					port);
932 		}
933 
934 		port->read_urb = port->read_urbs[0];
935 		port->bulk_in_buffer = port->bulk_in_buffers[0];
936 	}
937 
938 	for (i = 0; i < num_bulk_out; ++i) {
939 		endpoint = bulk_out_endpoint[i];
940 		port = serial->port[i];
941 		if (kfifo_alloc(&port->write_fifo, PAGE_SIZE, GFP_KERNEL))
942 			goto probe_error;
943 		buffer_size = max_t(int, serial->type->bulk_out_size,
944 						usb_endpoint_maxp(endpoint));
945 		port->bulk_out_size = buffer_size;
946 		port->bulk_out_endpointAddress = endpoint->bEndpointAddress;
947 
948 		for (j = 0; j < ARRAY_SIZE(port->write_urbs); ++j) {
949 			set_bit(j, &port->write_urbs_free);
950 			port->write_urbs[j] = usb_alloc_urb(0, GFP_KERNEL);
951 			if (!port->write_urbs[j])
952 				goto probe_error;
953 			port->bulk_out_buffers[j] = kmalloc(buffer_size,
954 								GFP_KERNEL);
955 			if (!port->bulk_out_buffers[j])
956 				goto probe_error;
957 			usb_fill_bulk_urb(port->write_urbs[j], dev,
958 					usb_sndbulkpipe(dev,
959 						endpoint->bEndpointAddress),
960 					port->bulk_out_buffers[j], buffer_size,
961 					serial->type->write_bulk_callback,
962 					port);
963 		}
964 
965 		port->write_urb = port->write_urbs[0];
966 		port->bulk_out_buffer = port->bulk_out_buffers[0];
967 	}
968 
969 	if (serial->type->read_int_callback) {
970 		for (i = 0; i < num_interrupt_in; ++i) {
971 			endpoint = interrupt_in_endpoint[i];
972 			port = serial->port[i];
973 			port->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
974 			if (!port->interrupt_in_urb)
975 				goto probe_error;
976 			buffer_size = usb_endpoint_maxp(endpoint);
977 			port->interrupt_in_endpointAddress =
978 						endpoint->bEndpointAddress;
979 			port->interrupt_in_buffer = kmalloc(buffer_size,
980 								GFP_KERNEL);
981 			if (!port->interrupt_in_buffer)
982 				goto probe_error;
983 			usb_fill_int_urb(port->interrupt_in_urb, dev,
984 				usb_rcvintpipe(dev,
985 						endpoint->bEndpointAddress),
986 				port->interrupt_in_buffer, buffer_size,
987 				serial->type->read_int_callback, port,
988 				endpoint->bInterval);
989 		}
990 	} else if (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 < num_interrupt_out; ++i) {
996 			endpoint = interrupt_out_endpoint[i];
997 			port = serial->port[i];
998 			port->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
999 			if (!port->interrupt_out_urb)
1000 				goto probe_error;
1001 			buffer_size = usb_endpoint_maxp(endpoint);
1002 			port->interrupt_out_size = buffer_size;
1003 			port->interrupt_out_endpointAddress =
1004 						endpoint->bEndpointAddress;
1005 			port->interrupt_out_buffer = kmalloc(buffer_size,
1006 								GFP_KERNEL);
1007 			if (!port->interrupt_out_buffer)
1008 				goto probe_error;
1009 			usb_fill_int_urb(port->interrupt_out_urb, dev,
1010 				usb_sndintpipe(dev,
1011 						  endpoint->bEndpointAddress),
1012 				port->interrupt_out_buffer, buffer_size,
1013 				serial->type->write_int_callback, port,
1014 				endpoint->bInterval);
1015 		}
1016 	} else if (num_interrupt_out) {
1017 		dev_dbg(ddev, "The device claims to support interrupt out transfers, but write_int_callback is not defined\n");
1018 	}
1019 
1020 	usb_set_intfdata(interface, serial);
1021 
1022 	/* if this device type has an attach function, call it */
1023 	if (type->attach) {
1024 		retval = type->attach(serial);
1025 		if (retval < 0)
1026 			goto probe_error;
1027 		serial->attached = 1;
1028 		if (retval > 0) {
1029 			/* quietly accept this device, but don't bind to a
1030 			   serial port as it's about to disappear */
1031 			serial->num_ports = 0;
1032 			goto exit;
1033 		}
1034 	} else {
1035 		serial->attached = 1;
1036 	}
1037 
1038 	/* Avoid race with tty_open and serial_install by setting the
1039 	 * disconnected flag and not clearing it until all ports have been
1040 	 * registered.
1041 	 */
1042 	serial->disconnected = 1;
1043 
1044 	if (allocate_minors(serial, num_ports)) {
1045 		dev_err(ddev, "No more free serial minor numbers\n");
1046 		goto probe_error;
1047 	}
1048 
1049 	/* register all of the individual ports with the driver core */
1050 	for (i = 0; i < num_ports; ++i) {
1051 		port = serial->port[i];
1052 		dev_set_name(&port->dev, "ttyUSB%d", port->minor);
1053 		dev_dbg(ddev, "registering %s\n", dev_name(&port->dev));
1054 		device_enable_async_suspend(&port->dev);
1055 
1056 		retval = device_add(&port->dev);
1057 		if (retval)
1058 			dev_err(ddev, "Error registering port device, continuing\n");
1059 	}
1060 
1061 	serial->disconnected = 0;
1062 
1063 	usb_serial_console_init(serial->port[0]->minor);
1064 exit:
1065 	module_put(type->driver.owner);
1066 	return 0;
1067 
1068 probe_error:
1069 	usb_serial_put(serial);
1070 	module_put(type->driver.owner);
1071 	return -EIO;
1072 }
1073 
1074 static void usb_serial_disconnect(struct usb_interface *interface)
1075 {
1076 	int i;
1077 	struct usb_serial *serial = usb_get_intfdata(interface);
1078 	struct device *dev = &interface->dev;
1079 	struct usb_serial_port *port;
1080 	struct tty_struct *tty;
1081 
1082 	usb_serial_console_disconnect(serial);
1083 
1084 	mutex_lock(&serial->disc_mutex);
1085 	/* must set a flag, to signal subdrivers */
1086 	serial->disconnected = 1;
1087 	mutex_unlock(&serial->disc_mutex);
1088 
1089 	for (i = 0; i < serial->num_ports; ++i) {
1090 		port = serial->port[i];
1091 		tty = tty_port_tty_get(&port->port);
1092 		if (tty) {
1093 			tty_vhangup(tty);
1094 			tty_kref_put(tty);
1095 		}
1096 		usb_serial_port_poison_urbs(port);
1097 		wake_up_interruptible(&port->port.delta_msr_wait);
1098 		cancel_work_sync(&port->work);
1099 		if (device_is_registered(&port->dev))
1100 			device_del(&port->dev);
1101 	}
1102 	if (serial->type->disconnect)
1103 		serial->type->disconnect(serial);
1104 
1105 	/* let the last holder of this object cause it to be cleaned up */
1106 	usb_serial_put(serial);
1107 	dev_info(dev, "device disconnected\n");
1108 }
1109 
1110 int usb_serial_suspend(struct usb_interface *intf, pm_message_t message)
1111 {
1112 	struct usb_serial *serial = usb_get_intfdata(intf);
1113 	int i, r = 0;
1114 
1115 	serial->suspending = 1;
1116 
1117 	/*
1118 	 * serial->type->suspend() MUST return 0 in system sleep context,
1119 	 * otherwise, the resume callback has to recover device from
1120 	 * previous suspend failure.
1121 	 */
1122 	if (serial->type->suspend) {
1123 		r = serial->type->suspend(serial, message);
1124 		if (r < 0) {
1125 			serial->suspending = 0;
1126 			goto err_out;
1127 		}
1128 	}
1129 
1130 	for (i = 0; i < serial->num_ports; ++i)
1131 		usb_serial_port_poison_urbs(serial->port[i]);
1132 err_out:
1133 	return r;
1134 }
1135 EXPORT_SYMBOL(usb_serial_suspend);
1136 
1137 static void usb_serial_unpoison_port_urbs(struct usb_serial *serial)
1138 {
1139 	int i;
1140 
1141 	for (i = 0; i < serial->num_ports; ++i)
1142 		usb_serial_port_unpoison_urbs(serial->port[i]);
1143 }
1144 
1145 int usb_serial_resume(struct usb_interface *intf)
1146 {
1147 	struct usb_serial *serial = usb_get_intfdata(intf);
1148 	int rv;
1149 
1150 	usb_serial_unpoison_port_urbs(serial);
1151 
1152 	serial->suspending = 0;
1153 	if (serial->type->resume)
1154 		rv = serial->type->resume(serial);
1155 	else
1156 		rv = usb_serial_generic_resume(serial);
1157 
1158 	return rv;
1159 }
1160 EXPORT_SYMBOL(usb_serial_resume);
1161 
1162 static int usb_serial_reset_resume(struct usb_interface *intf)
1163 {
1164 	struct usb_serial *serial = usb_get_intfdata(intf);
1165 	int rv;
1166 
1167 	usb_serial_unpoison_port_urbs(serial);
1168 
1169 	serial->suspending = 0;
1170 	if (serial->type->reset_resume) {
1171 		rv = serial->type->reset_resume(serial);
1172 	} else {
1173 		rv = -EOPNOTSUPP;
1174 		intf->needs_binding = 1;
1175 	}
1176 
1177 	return rv;
1178 }
1179 
1180 static const struct tty_operations serial_ops = {
1181 	.open =			serial_open,
1182 	.close =		serial_close,
1183 	.write =		serial_write,
1184 	.hangup =		serial_hangup,
1185 	.write_room =		serial_write_room,
1186 	.ioctl =		serial_ioctl,
1187 	.set_termios =		serial_set_termios,
1188 	.throttle =		serial_throttle,
1189 	.unthrottle =		serial_unthrottle,
1190 	.break_ctl =		serial_break,
1191 	.chars_in_buffer =	serial_chars_in_buffer,
1192 	.wait_until_sent =	serial_wait_until_sent,
1193 	.tiocmget =		serial_tiocmget,
1194 	.tiocmset =		serial_tiocmset,
1195 	.get_icount =		serial_get_icount,
1196 	.cleanup =		serial_cleanup,
1197 	.install =		serial_install,
1198 	.proc_fops =		&serial_proc_fops,
1199 };
1200 
1201 
1202 struct tty_driver *usb_serial_tty_driver;
1203 
1204 /* Driver structure we register with the USB core */
1205 static struct usb_driver usb_serial_driver = {
1206 	.name =		"usbserial",
1207 	.probe =	usb_serial_probe,
1208 	.disconnect =	usb_serial_disconnect,
1209 	.suspend =	usb_serial_suspend,
1210 	.resume =	usb_serial_resume,
1211 	.no_dynamic_id =	1,
1212 	.supports_autosuspend =	1,
1213 };
1214 
1215 static int __init usb_serial_init(void)
1216 {
1217 	int result;
1218 
1219 	usb_serial_tty_driver = alloc_tty_driver(USB_SERIAL_TTY_MINORS);
1220 	if (!usb_serial_tty_driver)
1221 		return -ENOMEM;
1222 
1223 	/* Initialize our global data */
1224 	result = bus_register(&usb_serial_bus_type);
1225 	if (result) {
1226 		pr_err("%s - registering bus driver failed\n", __func__);
1227 		goto exit_bus;
1228 	}
1229 
1230 	usb_serial_tty_driver->driver_name = "usbserial";
1231 	usb_serial_tty_driver->name = "ttyUSB";
1232 	usb_serial_tty_driver->major = USB_SERIAL_TTY_MAJOR;
1233 	usb_serial_tty_driver->minor_start = 0;
1234 	usb_serial_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
1235 	usb_serial_tty_driver->subtype = SERIAL_TYPE_NORMAL;
1236 	usb_serial_tty_driver->flags = TTY_DRIVER_REAL_RAW |
1237 						TTY_DRIVER_DYNAMIC_DEV;
1238 	usb_serial_tty_driver->init_termios = tty_std_termios;
1239 	usb_serial_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD
1240 							| HUPCL | CLOCAL;
1241 	usb_serial_tty_driver->init_termios.c_ispeed = 9600;
1242 	usb_serial_tty_driver->init_termios.c_ospeed = 9600;
1243 	tty_set_operations(usb_serial_tty_driver, &serial_ops);
1244 	result = tty_register_driver(usb_serial_tty_driver);
1245 	if (result) {
1246 		pr_err("%s - tty_register_driver failed\n", __func__);
1247 		goto exit_reg_driver;
1248 	}
1249 
1250 	/* register the USB driver */
1251 	result = usb_register(&usb_serial_driver);
1252 	if (result < 0) {
1253 		pr_err("%s - usb_register failed\n", __func__);
1254 		goto exit_tty;
1255 	}
1256 
1257 	/* register the generic driver, if we should */
1258 	result = usb_serial_generic_register();
1259 	if (result < 0) {
1260 		pr_err("%s - registering generic driver failed\n", __func__);
1261 		goto exit_generic;
1262 	}
1263 
1264 	return result;
1265 
1266 exit_generic:
1267 	usb_deregister(&usb_serial_driver);
1268 
1269 exit_tty:
1270 	tty_unregister_driver(usb_serial_tty_driver);
1271 
1272 exit_reg_driver:
1273 	bus_unregister(&usb_serial_bus_type);
1274 
1275 exit_bus:
1276 	pr_err("%s - returning with error %d\n", __func__, result);
1277 	put_tty_driver(usb_serial_tty_driver);
1278 	return result;
1279 }
1280 
1281 
1282 static void __exit usb_serial_exit(void)
1283 {
1284 	usb_serial_console_exit();
1285 
1286 	usb_serial_generic_deregister();
1287 
1288 	usb_deregister(&usb_serial_driver);
1289 	tty_unregister_driver(usb_serial_tty_driver);
1290 	put_tty_driver(usb_serial_tty_driver);
1291 	bus_unregister(&usb_serial_bus_type);
1292 }
1293 
1294 
1295 module_init(usb_serial_init);
1296 module_exit(usb_serial_exit);
1297 
1298 #define set_to_generic_if_null(type, function)				\
1299 	do {								\
1300 		if (!type->function) {					\
1301 			type->function = usb_serial_generic_##function;	\
1302 			pr_debug("%s: using generic " #function	"\n",	\
1303 						type->driver.name);	\
1304 		}							\
1305 	} while (0)
1306 
1307 static void usb_serial_operations_init(struct usb_serial_driver *device)
1308 {
1309 	set_to_generic_if_null(device, open);
1310 	set_to_generic_if_null(device, write);
1311 	set_to_generic_if_null(device, close);
1312 	set_to_generic_if_null(device, write_room);
1313 	set_to_generic_if_null(device, chars_in_buffer);
1314 	if (device->tx_empty)
1315 		set_to_generic_if_null(device, wait_until_sent);
1316 	set_to_generic_if_null(device, read_bulk_callback);
1317 	set_to_generic_if_null(device, write_bulk_callback);
1318 	set_to_generic_if_null(device, process_read_urb);
1319 	set_to_generic_if_null(device, prepare_write_buffer);
1320 }
1321 
1322 static int usb_serial_register(struct usb_serial_driver *driver)
1323 {
1324 	int retval;
1325 
1326 	if (usb_disabled())
1327 		return -ENODEV;
1328 
1329 	if (!driver->description)
1330 		driver->description = driver->driver.name;
1331 	if (!driver->usb_driver) {
1332 		WARN(1, "Serial driver %s has no usb_driver\n",
1333 				driver->description);
1334 		return -EINVAL;
1335 	}
1336 
1337 	usb_serial_operations_init(driver);
1338 
1339 	/* Add this device to our list of devices */
1340 	mutex_lock(&table_lock);
1341 	list_add(&driver->driver_list, &usb_serial_driver_list);
1342 
1343 	retval = usb_serial_bus_register(driver);
1344 	if (retval) {
1345 		pr_err("problem %d when registering driver %s\n", retval, driver->description);
1346 		list_del(&driver->driver_list);
1347 	} else {
1348 		pr_info("USB Serial support registered for %s\n", driver->description);
1349 	}
1350 	mutex_unlock(&table_lock);
1351 	return retval;
1352 }
1353 
1354 static void usb_serial_deregister(struct usb_serial_driver *device)
1355 {
1356 	pr_info("USB Serial deregistering driver %s\n", device->description);
1357 
1358 	mutex_lock(&table_lock);
1359 	list_del(&device->driver_list);
1360 	mutex_unlock(&table_lock);
1361 
1362 	usb_serial_bus_deregister(device);
1363 }
1364 
1365 /**
1366  * usb_serial_register_drivers - register drivers for a usb-serial module
1367  * @serial_drivers: NULL-terminated array of pointers to drivers to be registered
1368  * @name: name of the usb_driver for this set of @serial_drivers
1369  * @id_table: list of all devices this @serial_drivers set binds to
1370  *
1371  * Registers all the drivers in the @serial_drivers array, and dynamically
1372  * creates a struct usb_driver with the name @name and id_table of @id_table.
1373  */
1374 int usb_serial_register_drivers(struct usb_serial_driver *const serial_drivers[],
1375 				const char *name,
1376 				const struct usb_device_id *id_table)
1377 {
1378 	int rc;
1379 	struct usb_driver *udriver;
1380 	struct usb_serial_driver * const *sd;
1381 
1382 	/*
1383 	 * udriver must be registered before any of the serial drivers,
1384 	 * because the store_new_id() routine for the serial drivers (in
1385 	 * bus.c) probes udriver.
1386 	 *
1387 	 * Performance hack: We don't want udriver to be probed until
1388 	 * the serial drivers are registered, because the probe would
1389 	 * simply fail for lack of a matching serial driver.
1390 	 * So we leave udriver's id_table set to NULL until we are all set.
1391 	 *
1392 	 * Suspend/resume support is implemented in the usb-serial core,
1393 	 * so fill in the PM-related fields in udriver.
1394 	 */
1395 	udriver = kzalloc(sizeof(*udriver), GFP_KERNEL);
1396 	if (!udriver)
1397 		return -ENOMEM;
1398 
1399 	udriver->name = name;
1400 	udriver->no_dynamic_id = 1;
1401 	udriver->supports_autosuspend = 1;
1402 	udriver->suspend = usb_serial_suspend;
1403 	udriver->resume = usb_serial_resume;
1404 	udriver->probe = usb_serial_probe;
1405 	udriver->disconnect = usb_serial_disconnect;
1406 
1407 	/* we only set the reset_resume field if the serial_driver has one */
1408 	for (sd = serial_drivers; *sd; ++sd) {
1409 		if ((*sd)->reset_resume) {
1410 			udriver->reset_resume = usb_serial_reset_resume;
1411 			break;
1412 		}
1413 	}
1414 
1415 	rc = usb_register(udriver);
1416 	if (rc)
1417 		return rc;
1418 
1419 	for (sd = serial_drivers; *sd; ++sd) {
1420 		(*sd)->usb_driver = udriver;
1421 		rc = usb_serial_register(*sd);
1422 		if (rc)
1423 			goto failed;
1424 	}
1425 
1426 	/* Now set udriver's id_table and look for matches */
1427 	udriver->id_table = id_table;
1428 	rc = driver_attach(&udriver->drvwrap.driver);
1429 	return 0;
1430 
1431  failed:
1432 	while (sd-- > serial_drivers)
1433 		usb_serial_deregister(*sd);
1434 	usb_deregister(udriver);
1435 	return rc;
1436 }
1437 EXPORT_SYMBOL_GPL(usb_serial_register_drivers);
1438 
1439 /**
1440  * usb_serial_deregister_drivers - deregister drivers for a usb-serial module
1441  * @serial_drivers: NULL-terminated array of pointers to drivers to be deregistered
1442  *
1443  * Deregisters all the drivers in the @serial_drivers array and deregisters and
1444  * frees the struct usb_driver that was created by the call to
1445  * usb_serial_register_drivers().
1446  */
1447 void usb_serial_deregister_drivers(struct usb_serial_driver *const serial_drivers[])
1448 {
1449 	struct usb_driver *udriver = (*serial_drivers)->usb_driver;
1450 
1451 	for (; *serial_drivers; ++serial_drivers)
1452 		usb_serial_deregister(*serial_drivers);
1453 	usb_deregister(udriver);
1454 	kfree(udriver);
1455 }
1456 EXPORT_SYMBOL_GPL(usb_serial_deregister_drivers);
1457 
1458 MODULE_AUTHOR(DRIVER_AUTHOR);
1459 MODULE_DESCRIPTION(DRIVER_DESC);
1460 MODULE_LICENSE("GPL");
1461