USB: serial: refactor generic close
[linux-2.6.git] / drivers / usb / serial / generic.c
1 /*
2  * USB Serial Converter Generic functions
3  *
4  * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
5  *
6  *      This program is free software; you can redistribute it and/or
7  *      modify it under the terms of the GNU General Public License version
8  *      2 as published by the Free Software Foundation.
9  *
10  */
11
12 #include <linux/kernel.h>
13 #include <linux/errno.h>
14 #include <linux/slab.h>
15 #include <linux/sysrq.h>
16 #include <linux/tty.h>
17 #include <linux/tty_flip.h>
18 #include <linux/module.h>
19 #include <linux/moduleparam.h>
20 #include <linux/usb.h>
21 #include <linux/usb/serial.h>
22 #include <linux/uaccess.h>
23 #include <linux/kfifo.h>
24 #include <linux/serial.h>
25
26 static int debug;
27
28 #ifdef CONFIG_USB_SERIAL_GENERIC
29
30 static int generic_probe(struct usb_interface *interface,
31                          const struct usb_device_id *id);
32
33 static __u16 vendor  = 0x05f9;
34 static __u16 product = 0xffff;
35
36 module_param(vendor, ushort, 0);
37 MODULE_PARM_DESC(vendor, "User specified USB idVendor");
38
39 module_param(product, ushort, 0);
40 MODULE_PARM_DESC(product, "User specified USB idProduct");
41
42 static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */
43
44 /* we want to look at all devices, as the vendor/product id can change
45  * depending on the command line argument */
46 static const struct usb_device_id generic_serial_ids[] = {
47         {.driver_info = 42},
48         {}
49 };
50
51 static struct usb_driver generic_driver = {
52         .name =         "usbserial_generic",
53         .probe =        generic_probe,
54         .disconnect =   usb_serial_disconnect,
55         .id_table =     generic_serial_ids,
56         .no_dynamic_id =        1,
57 };
58
59 /* All of the device info needed for the Generic Serial Converter */
60 struct usb_serial_driver usb_serial_generic_device = {
61         .driver = {
62                 .owner =        THIS_MODULE,
63                 .name =         "generic",
64         },
65         .id_table =             generic_device_ids,
66         .usb_driver =           &generic_driver,
67         .num_ports =            1,
68         .disconnect =           usb_serial_generic_disconnect,
69         .release =              usb_serial_generic_release,
70         .throttle =             usb_serial_generic_throttle,
71         .unthrottle =           usb_serial_generic_unthrottle,
72         .resume =               usb_serial_generic_resume,
73 };
74
75 static int generic_probe(struct usb_interface *interface,
76                                const struct usb_device_id *id)
77 {
78         const struct usb_device_id *id_pattern;
79
80         id_pattern = usb_match_id(interface, generic_device_ids);
81         if (id_pattern != NULL)
82                 return usb_serial_probe(interface, id);
83         return -ENODEV;
84 }
85 #endif
86
87 int usb_serial_generic_register(int _debug)
88 {
89         int retval = 0;
90
91         debug = _debug;
92 #ifdef CONFIG_USB_SERIAL_GENERIC
93         generic_device_ids[0].idVendor = vendor;
94         generic_device_ids[0].idProduct = product;
95         generic_device_ids[0].match_flags =
96                 USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
97
98         /* register our generic driver with ourselves */
99         retval = usb_serial_register(&usb_serial_generic_device);
100         if (retval)
101                 goto exit;
102         retval = usb_register(&generic_driver);
103         if (retval)
104                 usb_serial_deregister(&usb_serial_generic_device);
105 exit:
106 #endif
107         return retval;
108 }
109
110 void usb_serial_generic_deregister(void)
111 {
112 #ifdef CONFIG_USB_SERIAL_GENERIC
113         /* remove our generic driver */
114         usb_deregister(&generic_driver);
115         usb_serial_deregister(&usb_serial_generic_device);
116 #endif
117 }
118
119 int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
120 {
121         struct usb_serial *serial = port->serial;
122         int result = 0;
123         unsigned long flags;
124
125         dbg("%s - port %d", __func__, port->number);
126
127         /* clear the throttle flags */
128         spin_lock_irqsave(&port->lock, flags);
129         port->throttled = 0;
130         port->throttle_req = 0;
131         spin_unlock_irqrestore(&port->lock, flags);
132
133         /* if we have a bulk endpoint, start reading from it */
134         if (port->bulk_in_size) {
135                 /* Start reading from the device */
136                 usb_fill_bulk_urb(port->read_urb, serial->dev,
137                                    usb_rcvbulkpipe(serial->dev,
138                                                 port->bulk_in_endpointAddress),
139                                    port->read_urb->transfer_buffer,
140                                    port->read_urb->transfer_buffer_length,
141                                    ((serial->type->read_bulk_callback) ?
142                                      serial->type->read_bulk_callback :
143                                      usb_serial_generic_read_bulk_callback),
144                                    port);
145                 result = usb_submit_urb(port->read_urb, GFP_KERNEL);
146                 if (result)
147                         dev_err(&port->dev,
148                             "%s - failed resubmitting read urb, error %d\n",
149                                                         __func__, result);
150         }
151
152         return result;
153 }
154 EXPORT_SYMBOL_GPL(usb_serial_generic_open);
155
156 static void generic_cleanup(struct usb_serial_port *port)
157 {
158         struct usb_serial *serial = port->serial;
159         unsigned long flags;
160
161         dbg("%s - port %d", __func__, port->number);
162
163         if (serial->dev) {
164                 /* shutdown any bulk transfers that might be going on */
165                 if (port->bulk_out_size) {
166                         usb_kill_urb(port->write_urb);
167
168                         spin_lock_irqsave(&port->lock, flags);
169                         kfifo_reset_out(&port->write_fifo);
170                         spin_unlock_irqrestore(&port->lock, flags);
171                 }
172                 if (port->bulk_in_size)
173                         usb_kill_urb(port->read_urb);
174         }
175 }
176
177 void usb_serial_generic_close(struct usb_serial_port *port)
178 {
179         dbg("%s - port %d", __func__, port->number);
180         generic_cleanup(port);
181 }
182 EXPORT_SYMBOL_GPL(usb_serial_generic_close);
183
184 static int usb_serial_multi_urb_write(struct tty_struct *tty,
185         struct usb_serial_port *port, const unsigned char *buf, int count)
186 {
187         unsigned long flags;
188         struct urb *urb;
189         unsigned char *buffer;
190         int status;
191         int towrite;
192         int bwrite = 0;
193
194         dbg("%s - port %d", __func__, port->number);
195
196         if (count == 0)
197                 dbg("%s - write request of 0 bytes", __func__);
198
199         while (count > 0) {
200                 towrite = (count > port->bulk_out_size) ?
201                         port->bulk_out_size : count;
202                 spin_lock_irqsave(&port->lock, flags);
203                 if (port->urbs_in_flight >
204                     port->serial->type->max_in_flight_urbs) {
205                         spin_unlock_irqrestore(&port->lock, flags);
206                         dbg("%s - write limit hit", __func__);
207                         return bwrite;
208                 }
209                 port->tx_bytes_flight += towrite;
210                 port->urbs_in_flight++;
211                 spin_unlock_irqrestore(&port->lock, flags);
212
213                 buffer = kmalloc(towrite, GFP_ATOMIC);
214                 if (!buffer) {
215                         dev_err(&port->dev,
216                         "%s ran out of kernel memory for urb ...\n", __func__);
217                         goto error_no_buffer;
218                 }
219
220                 urb = usb_alloc_urb(0, GFP_ATOMIC);
221                 if (!urb) {
222                         dev_err(&port->dev, "%s - no more free urbs\n",
223                                 __func__);
224                         goto error_no_urb;
225                 }
226
227                 /* Copy data */
228                 memcpy(buffer, buf + bwrite, towrite);
229                 usb_serial_debug_data(debug, &port->dev, __func__,
230                                       towrite, buffer);
231                 /* fill the buffer and send it */
232                 usb_fill_bulk_urb(urb, port->serial->dev,
233                         usb_sndbulkpipe(port->serial->dev,
234                                         port->bulk_out_endpointAddress),
235                         buffer, towrite,
236                         usb_serial_generic_write_bulk_callback, port);
237
238                 status = usb_submit_urb(urb, GFP_ATOMIC);
239                 if (status) {
240                         dev_err(&port->dev,
241                                 "%s - failed submitting write urb, error %d\n",
242                                 __func__, status);
243                         goto error;
244                 }
245
246                 /* This urb is the responsibility of the host driver now */
247                 usb_free_urb(urb);
248                 dbg("%s write: %d", __func__, towrite);
249                 count -= towrite;
250                 bwrite += towrite;
251         }
252         return bwrite;
253
254 error:
255         usb_free_urb(urb);
256 error_no_urb:
257         kfree(buffer);
258 error_no_buffer:
259         spin_lock_irqsave(&port->lock, flags);
260         port->urbs_in_flight--;
261         port->tx_bytes_flight -= towrite;
262         spin_unlock_irqrestore(&port->lock, flags);
263         return bwrite;
264 }
265
266 /**
267  * usb_serial_generic_write_start - kick off an URB write
268  * @port:       Pointer to the &struct usb_serial_port data
269  *
270  * Returns the number of bytes queued on success. This will be zero if there
271  * was nothing to send. Otherwise, it returns a negative errno value
272  */
273 static int usb_serial_generic_write_start(struct usb_serial_port *port)
274 {
275         struct usb_serial *serial = port->serial;
276         unsigned char *data;
277         int result;
278         int count;
279         unsigned long flags;
280         bool start_io;
281
282         /* Atomically determine whether we can and need to start a USB
283          * operation. */
284         spin_lock_irqsave(&port->lock, flags);
285         if (port->write_urb_busy)
286                 start_io = false;
287         else {
288                 start_io = (kfifo_len(&port->write_fifo) != 0);
289                 port->write_urb_busy = start_io;
290         }
291         spin_unlock_irqrestore(&port->lock, flags);
292
293         if (!start_io)
294                 return 0;
295
296         data = port->write_urb->transfer_buffer;
297         count = kfifo_out_locked(&port->write_fifo, data, port->bulk_out_size, &port->lock);
298         usb_serial_debug_data(debug, &port->dev, __func__, count, data);
299
300         /* set up our urb */
301         usb_fill_bulk_urb(port->write_urb, serial->dev,
302                            usb_sndbulkpipe(serial->dev,
303                                 port->bulk_out_endpointAddress),
304                            port->write_urb->transfer_buffer, count,
305                            ((serial->type->write_bulk_callback) ?
306                              serial->type->write_bulk_callback :
307                              usb_serial_generic_write_bulk_callback),
308                            port);
309
310         /* send the data out the bulk port */
311         result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
312         if (result) {
313                 dev_err(&port->dev,
314                         "%s - failed submitting write urb, error %d\n",
315                                                 __func__, result);
316                 /* don't have to grab the lock here, as we will
317                    retry if != 0 */
318                 port->write_urb_busy = 0;
319                 return result;
320         }
321
322         spin_lock_irqsave(&port->lock, flags);
323         port->tx_bytes_flight += count;
324         spin_unlock_irqrestore(&port->lock, flags);
325
326         return count;
327 }
328
329 /**
330  * usb_serial_generic_write - generic write function for serial USB devices
331  * @tty:        Pointer to &struct tty_struct for the device
332  * @port:       Pointer to the &usb_serial_port structure for the device
333  * @buf:        Pointer to the data to write
334  * @count:      Number of bytes to write
335  *
336  * Returns the number of characters actually written, which may be anything
337  * from zero to @count. If an error occurs, it returns the negative errno
338  * value.
339  */
340 int usb_serial_generic_write(struct tty_struct *tty,
341         struct usb_serial_port *port, const unsigned char *buf, int count)
342 {
343         struct usb_serial *serial = port->serial;
344         int result;
345
346         dbg("%s - port %d", __func__, port->number);
347
348         /* only do something if we have a bulk out endpoint */
349         if (!port->bulk_out_size)
350                 return -ENODEV;
351
352         if (count == 0) {
353                 dbg("%s - write request of 0 bytes", __func__);
354                 return 0;
355         }
356
357         if (serial->type->max_in_flight_urbs)
358                 return usb_serial_multi_urb_write(tty, port,
359                                                   buf, count);
360
361         count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
362         result = usb_serial_generic_write_start(port);
363
364         if (result >= 0)
365                 result = count;
366
367         return result;
368 }
369 EXPORT_SYMBOL_GPL(usb_serial_generic_write);
370
371 int usb_serial_generic_write_room(struct tty_struct *tty)
372 {
373         struct usb_serial_port *port = tty->driver_data;
374         struct usb_serial *serial = port->serial;
375         unsigned long flags;
376         int room = 0;
377
378         dbg("%s - port %d", __func__, port->number);
379
380         if (!port->bulk_out_size)
381                 return 0;
382
383         spin_lock_irqsave(&port->lock, flags);
384         if (serial->type->max_in_flight_urbs) {
385                 if (port->urbs_in_flight < serial->type->max_in_flight_urbs)
386                         room = port->bulk_out_size *
387                                 (serial->type->max_in_flight_urbs -
388                                  port->urbs_in_flight);
389         } else {
390                 room = kfifo_avail(&port->write_fifo);
391         }
392         spin_unlock_irqrestore(&port->lock, flags);
393
394         dbg("%s - returns %d", __func__, room);
395         return room;
396 }
397
398 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
399 {
400         struct usb_serial_port *port = tty->driver_data;
401         struct usb_serial *serial = port->serial;
402         unsigned long flags;
403         int chars;
404
405         dbg("%s - port %d", __func__, port->number);
406
407         if (!port->bulk_out_size)
408                 return 0;
409
410         spin_lock_irqsave(&port->lock, flags);
411         if (serial->type->max_in_flight_urbs)
412                 chars = port->tx_bytes_flight;
413         else
414                 chars = kfifo_len(&port->write_fifo) + port->tx_bytes_flight;
415         spin_unlock_irqrestore(&port->lock, flags);
416
417         dbg("%s - returns %d", __func__, chars);
418         return chars;
419 }
420
421
422 void usb_serial_generic_resubmit_read_urb(struct usb_serial_port *port,
423                         gfp_t mem_flags)
424 {
425         struct urb *urb = port->read_urb;
426         struct usb_serial *serial = port->serial;
427         int result;
428
429         /* Continue reading from device */
430         usb_fill_bulk_urb(urb, serial->dev,
431                            usb_rcvbulkpipe(serial->dev,
432                                         port->bulk_in_endpointAddress),
433                            urb->transfer_buffer,
434                            urb->transfer_buffer_length,
435                            ((serial->type->read_bulk_callback) ?
436                              serial->type->read_bulk_callback :
437                              usb_serial_generic_read_bulk_callback), port);
438
439         result = usb_submit_urb(urb, mem_flags);
440         if (result && result != -EPERM) {
441                 dev_err(&port->dev,
442                         "%s - failed resubmitting read urb, error %d\n",
443                                                         __func__, result);
444         }
445 }
446 EXPORT_SYMBOL_GPL(usb_serial_generic_resubmit_read_urb);
447
448 /* Push data to tty layer and resubmit the bulk read URB */
449 static void flush_and_resubmit_read_urb(struct usb_serial_port *port)
450 {
451         struct urb *urb = port->read_urb;
452         struct tty_struct *tty = tty_port_tty_get(&port->port);
453         char *ch = (char *)urb->transfer_buffer;
454         int i;
455
456         if (!tty)
457                 goto done;
458
459         /* The per character mucking around with sysrq path it too slow for
460            stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
461            where the USB serial is not a console anyway */
462         if (!port->port.console || !port->sysrq)
463                 tty_insert_flip_string(tty, ch, urb->actual_length);
464         else {
465                 /* Push data to tty */
466                 for (i = 0; i < urb->actual_length; i++, ch++) {
467                         if (!usb_serial_handle_sysrq_char(tty, port, *ch))
468                                 tty_insert_flip_char(tty, *ch, TTY_NORMAL);
469                 }
470         }
471         tty_flip_buffer_push(tty);
472         tty_kref_put(tty);
473 done:
474         usb_serial_generic_resubmit_read_urb(port, GFP_ATOMIC);
475 }
476
477 void usb_serial_generic_read_bulk_callback(struct urb *urb)
478 {
479         struct usb_serial_port *port = urb->context;
480         unsigned char *data = urb->transfer_buffer;
481         int status = urb->status;
482         unsigned long flags;
483
484         dbg("%s - port %d", __func__, port->number);
485
486         if (unlikely(status != 0)) {
487                 dbg("%s - nonzero read bulk status received: %d",
488                     __func__, status);
489                 return;
490         }
491
492         usb_serial_debug_data(debug, &port->dev, __func__,
493                                                 urb->actual_length, data);
494
495         /* Throttle the device if requested by tty */
496         spin_lock_irqsave(&port->lock, flags);
497         port->throttled = port->throttle_req;
498         if (!port->throttled) {
499                 spin_unlock_irqrestore(&port->lock, flags);
500                 flush_and_resubmit_read_urb(port);
501         } else
502                 spin_unlock_irqrestore(&port->lock, flags);
503 }
504 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
505
506 void usb_serial_generic_write_bulk_callback(struct urb *urb)
507 {
508         unsigned long flags;
509         struct usb_serial_port *port = urb->context;
510         int status = urb->status;
511
512         dbg("%s - port %d", __func__, port->number);
513
514         if (port->serial->type->max_in_flight_urbs) {
515                 kfree(urb->transfer_buffer);
516
517                 spin_lock_irqsave(&port->lock, flags);
518                 --port->urbs_in_flight;
519                 port->tx_bytes_flight -= urb->transfer_buffer_length;
520                 if (port->urbs_in_flight < 0)
521                         port->urbs_in_flight = 0;
522                 spin_unlock_irqrestore(&port->lock, flags);
523         } else {
524                 spin_lock_irqsave(&port->lock, flags);
525                 port->tx_bytes_flight -= urb->transfer_buffer_length;
526                 port->write_urb_busy = 0;
527                 spin_unlock_irqrestore(&port->lock, flags);
528
529                 if (status) {
530                         spin_lock_irqsave(&port->lock, flags);
531                         kfifo_reset_out(&port->write_fifo);
532                         spin_unlock_irqrestore(&port->lock, flags);
533                 } else {
534                         usb_serial_generic_write_start(port);
535                 }
536         }
537
538         if (status)
539                 dbg("%s - non-zero urb status: %d", __func__, status);
540
541         usb_serial_port_softint(port);
542 }
543 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
544
545 void usb_serial_generic_throttle(struct tty_struct *tty)
546 {
547         struct usb_serial_port *port = tty->driver_data;
548         unsigned long flags;
549
550         dbg("%s - port %d", __func__, port->number);
551
552         /* Set the throttle request flag. It will be picked up
553          * by usb_serial_generic_read_bulk_callback(). */
554         spin_lock_irqsave(&port->lock, flags);
555         port->throttle_req = 1;
556         spin_unlock_irqrestore(&port->lock, flags);
557 }
558
559 void usb_serial_generic_unthrottle(struct tty_struct *tty)
560 {
561         struct usb_serial_port *port = tty->driver_data;
562         int was_throttled;
563         unsigned long flags;
564
565         dbg("%s - port %d", __func__, port->number);
566
567         /* Clear the throttle flags */
568         spin_lock_irqsave(&port->lock, flags);
569         was_throttled = port->throttled;
570         port->throttled = port->throttle_req = 0;
571         spin_unlock_irqrestore(&port->lock, flags);
572
573         if (was_throttled) {
574                 /* Resume reading from device */
575                 flush_and_resubmit_read_urb(port);
576         }
577 }
578
579 #ifdef CONFIG_MAGIC_SYSRQ
580 int usb_serial_handle_sysrq_char(struct tty_struct *tty,
581                         struct usb_serial_port *port, unsigned int ch)
582 {
583         if (port->sysrq && port->port.console) {
584                 if (ch && time_before(jiffies, port->sysrq)) {
585                         handle_sysrq(ch, tty);
586                         port->sysrq = 0;
587                         return 1;
588                 }
589                 port->sysrq = 0;
590         }
591         return 0;
592 }
593 #else
594 int usb_serial_handle_sysrq_char(struct tty_struct *tty,
595                         struct usb_serial_port *port, unsigned int ch)
596 {
597         return 0;
598 }
599 #endif
600 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
601
602 int usb_serial_handle_break(struct usb_serial_port *port)
603 {
604         if (!port->sysrq) {
605                 port->sysrq = jiffies + HZ*5;
606                 return 1;
607         }
608         port->sysrq = 0;
609         return 0;
610 }
611 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
612
613 int usb_serial_generic_resume(struct usb_serial *serial)
614 {
615         struct usb_serial_port *port;
616         int i, c = 0, r;
617
618         for (i = 0; i < serial->num_ports; i++) {
619                 port = serial->port[i];
620                 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
621                         continue;
622
623                 if (port->read_urb) {
624                         r = usb_submit_urb(port->read_urb, GFP_NOIO);
625                         if (r < 0)
626                                 c++;
627                 }
628
629                 if (port->write_urb) {
630                         r = usb_serial_generic_write_start(port);
631                         if (r < 0)
632                                 c++;
633                 }
634         }
635
636         return c ? -EIO : 0;
637 }
638 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);
639
640 void usb_serial_generic_disconnect(struct usb_serial *serial)
641 {
642         int i;
643
644         dbg("%s", __func__);
645
646         /* stop reads and writes on all ports */
647         for (i = 0; i < serial->num_ports; ++i)
648                 generic_cleanup(serial->port[i]);
649 }
650
651 void usb_serial_generic_release(struct usb_serial *serial)
652 {
653         dbg("%s", __func__);
654 }