e4db5ad2bc55f1c37f2da2b15c086534e98248c7
[pandora-kernel.git] / drivers / usb / serial / generic.c
1 /*
2  * USB Serial Converter Generic functions
3  *
4  * Copyright (C) 2010 Johan Hovold (jhovold@gmail.com)
5  * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
6  *
7  *      This program is free software; you can redistribute it and/or
8  *      modify it under the terms of the GNU General Public License version
9  *      2 as published by the Free Software Foundation.
10  *
11  */
12
13 #include <linux/kernel.h>
14 #include <linux/errno.h>
15 #include <linux/slab.h>
16 #include <linux/sysrq.h>
17 #include <linux/tty.h>
18 #include <linux/tty_flip.h>
19 #include <linux/module.h>
20 #include <linux/moduleparam.h>
21 #include <linux/usb.h>
22 #include <linux/usb/serial.h>
23 #include <linux/uaccess.h>
24 #include <linux/kfifo.h>
25 #include <linux/serial.h>
26
27 static int debug;
28
29 #ifdef CONFIG_USB_SERIAL_GENERIC
30
31 static int generic_probe(struct usb_interface *interface,
32                          const struct usb_device_id *id);
33
34 static __u16 vendor  = 0x05f9;
35 static __u16 product = 0xffff;
36
37 module_param(vendor, ushort, 0);
38 MODULE_PARM_DESC(vendor, "User specified USB idVendor");
39
40 module_param(product, ushort, 0);
41 MODULE_PARM_DESC(product, "User specified USB idProduct");
42
43 static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */
44
45 /* we want to look at all devices, as the vendor/product id can change
46  * depending on the command line argument */
47 static const struct usb_device_id generic_serial_ids[] = {
48         {.driver_info = 42},
49         {}
50 };
51
52 static struct usb_driver generic_driver = {
53         .name =         "usbserial_generic",
54         .probe =        generic_probe,
55         .disconnect =   usb_serial_disconnect,
56         .id_table =     generic_serial_ids,
57         .no_dynamic_id =        1,
58 };
59
60 /* All of the device info needed for the Generic Serial Converter */
61 struct usb_serial_driver usb_serial_generic_device = {
62         .driver = {
63                 .owner =        THIS_MODULE,
64                 .name =         "generic",
65         },
66         .id_table =             generic_device_ids,
67         .usb_driver =           &generic_driver,
68         .num_ports =            1,
69         .disconnect =           usb_serial_generic_disconnect,
70         .release =              usb_serial_generic_release,
71         .throttle =             usb_serial_generic_throttle,
72         .unthrottle =           usb_serial_generic_unthrottle,
73         .resume =               usb_serial_generic_resume,
74 };
75
76 static int generic_probe(struct usb_interface *interface,
77                                const struct usb_device_id *id)
78 {
79         const struct usb_device_id *id_pattern;
80
81         id_pattern = usb_match_id(interface, generic_device_ids);
82         if (id_pattern != NULL)
83                 return usb_serial_probe(interface, id);
84         return -ENODEV;
85 }
86 #endif
87
88 int usb_serial_generic_register(int _debug)
89 {
90         int retval = 0;
91
92         debug = _debug;
93 #ifdef CONFIG_USB_SERIAL_GENERIC
94         generic_device_ids[0].idVendor = vendor;
95         generic_device_ids[0].idProduct = product;
96         generic_device_ids[0].match_flags =
97                 USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
98
99         /* register our generic driver with ourselves */
100         retval = usb_serial_register(&usb_serial_generic_device);
101         if (retval)
102                 goto exit;
103         retval = usb_register(&generic_driver);
104         if (retval)
105                 usb_serial_deregister(&usb_serial_generic_device);
106 exit:
107 #endif
108         return retval;
109 }
110
111 void usb_serial_generic_deregister(void)
112 {
113 #ifdef CONFIG_USB_SERIAL_GENERIC
114         /* remove our generic driver */
115         usb_deregister(&generic_driver);
116         usb_serial_deregister(&usb_serial_generic_device);
117 #endif
118 }
119
120 int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
121 {
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                 result = usb_serial_generic_submit_read_urb(port, GFP_KERNEL);
136
137         return result;
138 }
139 EXPORT_SYMBOL_GPL(usb_serial_generic_open);
140
141 static void generic_cleanup(struct usb_serial_port *port)
142 {
143         struct usb_serial *serial = port->serial;
144         unsigned long flags;
145         int i;
146
147         dbg("%s - port %d", __func__, port->number);
148
149         if (serial->dev) {
150                 /* shutdown any bulk transfers that might be going on */
151                 if (port->bulk_out_size) {
152                         usb_kill_urb(port->write_urb);
153                         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
154                                 usb_kill_urb(port->write_urbs[i]);
155
156                         spin_lock_irqsave(&port->lock, flags);
157                         kfifo_reset_out(&port->write_fifo);
158                         spin_unlock_irqrestore(&port->lock, flags);
159                 }
160                 if (port->bulk_in_size)
161                         usb_kill_urb(port->read_urb);
162         }
163 }
164
165 void usb_serial_generic_close(struct usb_serial_port *port)
166 {
167         dbg("%s - port %d", __func__, port->number);
168         generic_cleanup(port);
169 }
170 EXPORT_SYMBOL_GPL(usb_serial_generic_close);
171
172 int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port,
173                                                 void *dest, size_t size)
174 {
175         return kfifo_out_locked(&port->write_fifo, dest, size, &port->lock);
176 }
177
178 /**
179  * usb_serial_generic_write_start - kick off an URB write
180  * @port:       Pointer to the &struct usb_serial_port data
181  *
182  * Returns zero on success, or a negative errno value
183  */
184 static int usb_serial_generic_write_start(struct usb_serial_port *port)
185 {
186         struct urb *urb;
187         int count, result;
188         unsigned long flags;
189         int i;
190
191         if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags))
192                 return 0;
193 retry:
194         spin_lock_irqsave(&port->lock, flags);
195         if (!port->write_urbs_free || !kfifo_len(&port->write_fifo)) {
196                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
197                 spin_unlock_irqrestore(&port->lock, flags);
198                 return 0;
199         }
200         i = (int)find_first_bit(&port->write_urbs_free,
201                                                 ARRAY_SIZE(port->write_urbs));
202         spin_unlock_irqrestore(&port->lock, flags);
203
204         urb = port->write_urbs[i];
205         count = port->serial->type->prepare_write_buffer(port,
206                                                 urb->transfer_buffer,
207                                                 port->bulk_out_size);
208         urb->transfer_buffer_length = count;
209         usb_serial_debug_data(debug, &port->dev, __func__, count,
210                                                 urb->transfer_buffer);
211         spin_lock_irqsave(&port->lock, flags);
212         port->tx_bytes += count;
213         spin_unlock_irqrestore(&port->lock, flags);
214
215         clear_bit(i, &port->write_urbs_free);
216         result = usb_submit_urb(urb, GFP_ATOMIC);
217         if (result) {
218                 dev_err(&port->dev, "%s - error submitting urb: %d\n",
219                                                 __func__, result);
220                 set_bit(i, &port->write_urbs_free);
221                 spin_lock_irqsave(&port->lock, flags);
222                 port->tx_bytes -= count;
223                 spin_unlock_irqrestore(&port->lock, flags);
224
225                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
226                 return result;
227         }
228
229         /* Try sending off another urb, unless in irq context (in which case
230          * there will be no free urb). */
231         if (!in_irq())
232                 goto retry;
233
234         clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
235
236         return 0;
237 }
238
239 /**
240  * usb_serial_generic_write - generic write function for serial USB devices
241  * @tty:        Pointer to &struct tty_struct for the device
242  * @port:       Pointer to the &usb_serial_port structure for the device
243  * @buf:        Pointer to the data to write
244  * @count:      Number of bytes to write
245  *
246  * Returns the number of characters actually written, which may be anything
247  * from zero to @count. If an error occurs, it returns the negative errno
248  * value.
249  */
250 int usb_serial_generic_write(struct tty_struct *tty,
251         struct usb_serial_port *port, const unsigned char *buf, int count)
252 {
253         int result;
254
255         dbg("%s - port %d", __func__, port->number);
256
257         /* only do something if we have a bulk out endpoint */
258         if (!port->bulk_out_size)
259                 return -ENODEV;
260
261         if (!count)
262                 return 0;
263
264         count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
265         result = usb_serial_generic_write_start(port);
266         if (result)
267                 return result;
268
269         return count;
270 }
271 EXPORT_SYMBOL_GPL(usb_serial_generic_write);
272
273 int usb_serial_generic_write_room(struct tty_struct *tty)
274 {
275         struct usb_serial_port *port = tty->driver_data;
276         unsigned long flags;
277         int room;
278
279         dbg("%s - port %d", __func__, port->number);
280
281         if (!port->bulk_out_size)
282                 return 0;
283
284         spin_lock_irqsave(&port->lock, flags);
285         room = kfifo_avail(&port->write_fifo);
286         spin_unlock_irqrestore(&port->lock, flags);
287
288         dbg("%s - returns %d", __func__, room);
289         return room;
290 }
291
292 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
293 {
294         struct usb_serial_port *port = tty->driver_data;
295         unsigned long flags;
296         int chars;
297
298         dbg("%s - port %d", __func__, port->number);
299
300         if (!port->bulk_out_size)
301                 return 0;
302
303         spin_lock_irqsave(&port->lock, flags);
304         chars = kfifo_len(&port->write_fifo) + port->tx_bytes;
305         spin_unlock_irqrestore(&port->lock, flags);
306
307         dbg("%s - returns %d", __func__, chars);
308         return chars;
309 }
310
311 int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
312                                         gfp_t mem_flags)
313 {
314         int result;
315
316         result = usb_submit_urb(port->read_urb, mem_flags);
317         if (result && result != -EPERM) {
318                 dev_err(&port->dev, "%s - error submitting urb: %d\n",
319                                                         __func__, result);
320         }
321         return result;
322 }
323 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urb);
324
325 void usb_serial_generic_process_read_urb(struct urb *urb)
326 {
327         struct usb_serial_port *port = urb->context;
328         struct tty_struct *tty;
329         char *ch = (char *)urb->transfer_buffer;
330         int i;
331
332         if (!urb->actual_length)
333                 return;
334
335         tty = tty_port_tty_get(&port->port);
336         if (!tty)
337                 return;
338
339         /* The per character mucking around with sysrq path it too slow for
340            stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
341            where the USB serial is not a console anyway */
342         if (!port->port.console || !port->sysrq)
343                 tty_insert_flip_string(tty, ch, urb->actual_length);
344         else {
345                 for (i = 0; i < urb->actual_length; i++, ch++) {
346                         if (!usb_serial_handle_sysrq_char(port, *ch))
347                                 tty_insert_flip_char(tty, *ch, TTY_NORMAL);
348                 }
349         }
350         tty_flip_buffer_push(tty);
351         tty_kref_put(tty);
352 }
353 EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb);
354
355 void usb_serial_generic_read_bulk_callback(struct urb *urb)
356 {
357         struct usb_serial_port *port = urb->context;
358         unsigned char *data = urb->transfer_buffer;
359         int status = urb->status;
360         unsigned long flags;
361
362         dbg("%s - port %d", __func__, port->number);
363
364         if (unlikely(status != 0)) {
365                 dbg("%s - nonzero read bulk status received: %d",
366                     __func__, status);
367                 return;
368         }
369
370         usb_serial_debug_data(debug, &port->dev, __func__,
371                                                 urb->actual_length, data);
372         port->serial->type->process_read_urb(urb);
373
374         /* Throttle the device if requested by tty */
375         spin_lock_irqsave(&port->lock, flags);
376         port->throttled = port->throttle_req;
377         if (!port->throttled) {
378                 spin_unlock_irqrestore(&port->lock, flags);
379                 usb_serial_generic_submit_read_urb(port, GFP_ATOMIC);
380         } else
381                 spin_unlock_irqrestore(&port->lock, flags);
382 }
383 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
384
385 void usb_serial_generic_write_bulk_callback(struct urb *urb)
386 {
387         unsigned long flags;
388         struct usb_serial_port *port = urb->context;
389         int status = urb->status;
390         int i;
391
392         dbg("%s - port %d", __func__, port->number);
393
394         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
395                 if (port->write_urbs[i] == urb)
396                         break;
397
398         spin_lock_irqsave(&port->lock, flags);
399         port->tx_bytes -= urb->transfer_buffer_length;
400         set_bit(i, &port->write_urbs_free);
401         spin_unlock_irqrestore(&port->lock, flags);
402
403         if (status) {
404                 dbg("%s - non-zero urb status: %d", __func__, status);
405
406                 spin_lock_irqsave(&port->lock, flags);
407                 kfifo_reset_out(&port->write_fifo);
408                 spin_unlock_irqrestore(&port->lock, flags);
409         } else {
410                 usb_serial_generic_write_start(port);
411         }
412
413         usb_serial_port_softint(port);
414 }
415 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
416
417 void usb_serial_generic_throttle(struct tty_struct *tty)
418 {
419         struct usb_serial_port *port = tty->driver_data;
420         unsigned long flags;
421
422         dbg("%s - port %d", __func__, port->number);
423
424         /* Set the throttle request flag. It will be picked up
425          * by usb_serial_generic_read_bulk_callback(). */
426         spin_lock_irqsave(&port->lock, flags);
427         port->throttle_req = 1;
428         spin_unlock_irqrestore(&port->lock, flags);
429 }
430 EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
431
432 void usb_serial_generic_unthrottle(struct tty_struct *tty)
433 {
434         struct usb_serial_port *port = tty->driver_data;
435         int was_throttled;
436
437         dbg("%s - port %d", __func__, port->number);
438
439         /* Clear the throttle flags */
440         spin_lock_irq(&port->lock);
441         was_throttled = port->throttled;
442         port->throttled = port->throttle_req = 0;
443         spin_unlock_irq(&port->lock);
444
445         if (was_throttled)
446                 usb_serial_generic_submit_read_urb(port, GFP_KERNEL);
447 }
448 EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
449
450 #ifdef CONFIG_MAGIC_SYSRQ
451 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
452 {
453         if (port->sysrq && port->port.console) {
454                 if (ch && time_before(jiffies, port->sysrq)) {
455                         handle_sysrq(ch);
456                         port->sysrq = 0;
457                         return 1;
458                 }
459                 port->sysrq = 0;
460         }
461         return 0;
462 }
463 #else
464 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
465 {
466         return 0;
467 }
468 #endif
469 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
470
471 int usb_serial_handle_break(struct usb_serial_port *port)
472 {
473         if (!port->sysrq) {
474                 port->sysrq = jiffies + HZ*5;
475                 return 1;
476         }
477         port->sysrq = 0;
478         return 0;
479 }
480 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
481
482 /**
483  *      usb_serial_handle_dcd_change - handle a change of carrier detect state
484  *      @port: usb_serial_port structure for the open port
485  *      @tty: tty_struct structure for the port
486  *      @status: new carrier detect status, nonzero if active
487  */
488 void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
489                                 struct tty_struct *tty, unsigned int status)
490 {
491         struct tty_port *port = &usb_port->port;
492
493         dbg("%s - port %d, status %d", __func__, usb_port->number, status);
494
495         if (status)
496                 wake_up_interruptible(&port->open_wait);
497         else if (tty && !C_CLOCAL(tty))
498                 tty_hangup(tty);
499 }
500 EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);
501
502 int usb_serial_generic_resume(struct usb_serial *serial)
503 {
504         struct usb_serial_port *port;
505         int i, c = 0, r;
506
507         for (i = 0; i < serial->num_ports; i++) {
508                 port = serial->port[i];
509                 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
510                         continue;
511
512                 if (port->read_urb) {
513                         r = usb_submit_urb(port->read_urb, GFP_NOIO);
514                         if (r < 0)
515                                 c++;
516                 }
517
518                 if (port->bulk_out_size) {
519                         r = usb_serial_generic_write_start(port);
520                         if (r < 0)
521                                 c++;
522                 }
523         }
524
525         return c ? -EIO : 0;
526 }
527 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);
528
529 void usb_serial_generic_disconnect(struct usb_serial *serial)
530 {
531         int i;
532
533         dbg("%s", __func__);
534
535         /* stop reads and writes on all ports */
536         for (i = 0; i < serial->num_ports; ++i)
537                 generic_cleanup(serial->port[i]);
538 }
539 EXPORT_SYMBOL_GPL(usb_serial_generic_disconnect);
540
541 void usb_serial_generic_release(struct usb_serial *serial)
542 {
543         dbg("%s", __func__);
544 }