1 /*
2 * AIRcable USB Bluetooth Dongle Driver.
3 *
4 * Copyright (C) 2006 Manuel Francisco Naranjo (naranjo.manuel@gmail.com)
5 * This program is free software; you can redistribute it and/or modify it under
6 * the terms of the GNU General Public License version 2 as published by the
7 * Free Software Foundation.
8 *
9 * The device works as an standard CDC device, it has 2 interfaces, the first
10 * one is for firmware access and the second is the serial one.
11 * The protocol is very simply, there are two posibilities reading or writing.
12 * When writing the first urb must have a Header that starts with 0x20 0x29 the
13 * next two bytes must say how much data will be sended.
14 * When reading the process is almost equal except that the header starts with
15 * 0x00 0x20.
16 *
17 * The device simply need some stuff to understand data comming from the usb
18 * buffer: The First and Second byte is used for a Header, the Third and Fourth
19 * tells the device the amount of information the package holds.
20 * Packages are 60 bytes long Header Stuff.
21 * When writing to the device the first two bytes of the header are 0x20 0x29
22 * When reading the bytes are 0x00 0x20, or 0x00 0x10, there is an strange
23 * situation, when too much data arrives to the device because it sends the data
24 * but with out the header. I will use a simply hack to override this situation,
25 * if there is data coming that does not contain any header, then that is data
26 * that must go directly to the tty, as there is no documentation about if there
27 * is any other control code, I will simply check for the first
28 * one.
29 *
30 * The driver registers himself with the USB-serial core and the USB Core. I had
31 * to implement a probe function agains USB-serial, because other way, the
32 * driver was attaching himself to both interfaces. I have tryed with different
33 * configurations of usb_serial_driver with out exit, only the probe function
34 * could handle this correctly.
35 *
36 * I have taken some info from a Greg Kroah-Hartman article:
37 * http://www.linuxjournal.com/article/6573
38 * And from Linux Device Driver Kit CD, which is a great work, the authors taken
39 * the work to recompile lots of information an knowladge in drivers development
40 * and made it all avaible inside a cd.
41 * URL: http://kernel.org/pub/linux/kernel/people/gregkh/ddk/
42 *
43 */
44
45 #include <linux/tty.h>
46 #include <linux/tty_flip.h>
47 #include <linux/circ_buf.h>
48 #include <linux/usb.h>
49 #include <linux/usb/serial.h>
50
51 static int debug;
52
53 /* Vendor and Product ID */
54 #define AIRCABLE_VID 0x16CA
55 #define AIRCABLE_USB_PID 0x1502
56
57 /* write buffer size defines */
58 #define AIRCABLE_BUF_SIZE 2048
59
60 /* Protocol Stuff */
61 #define HCI_HEADER_LENGTH 0x4
62 #define TX_HEADER_0 0x20
63 #define TX_HEADER_1 0x29
64 #define RX_HEADER_0 0x00
65 #define RX_HEADER_1 0x20
66 #define MAX_HCI_FRAMESIZE 60
67 #define HCI_COMPLETE_FRAME 64
68
69 /* rx_flags */
70 #define THROTTLED 0x01
71 #define ACTUALLY_THROTTLED 0x02
72
73 /*
74 * Version Information
75 */
76 #define DRIVER_VERSION "v1.0b2"
77 #define DRIVER_AUTHOR "Naranjo, Manuel Francisco <naranjo.manuel@gmail.com>"
78 #define DRIVER_DESC "AIRcable USB Driver"
79
80 /* ID table that will be registered with USB core */
81 static struct usb_device_id id_table [] = {
82 { USB_DEVICE(AIRCABLE_VID, AIRCABLE_USB_PID) },
83 { },
84 };
85 MODULE_DEVICE_TABLE(usb, id_table);
86
87
88 /* Internal Structure */
89 struct aircable_private {
90 spinlock_t rx_lock; /* spinlock for the receive lines */
91 struct circ_buf *tx_buf; /* write buffer */
92 struct circ_buf *rx_buf; /* read buffer */
93 int rx_flags; /* for throttilng */
94 struct work_struct rx_work; /* work cue for the receiving line */
95 struct usb_serial_port *port; /* USB port with which associated */
96 };
97
98 /* Private methods */
99
100 /* Circular Buffer Methods, code from ti_usb_3410_5052 used */
101 /*
102 * serial_buf_clear
103 *
104 * Clear out all data in the circular buffer.
105 */
106 static void serial_buf_clear(struct circ_buf *cb)
107 {
108 cb->head = cb->tail = 0;
109 }
110
111 /*
112 * serial_buf_alloc
113 *
114 * Allocate a circular buffer and all associated memory.
115 */
116 static struct circ_buf *serial_buf_alloc(void)
117 {
118 struct circ_buf *cb;
119 cb = kmalloc(sizeof(struct circ_buf), GFP_KERNEL);
120 if (cb == NULL)
121 return NULL;
122 cb->buf = kmalloc(AIRCABLE_BUF_SIZE, GFP_KERNEL);
123 if (cb->buf == NULL) {
124 kfree(cb);
125 return NULL;
126 }
127 serial_buf_clear(cb);
128 return cb;
129 }
130
131 /*
132 * serial_buf_free
133 *
134 * Free the buffer and all associated memory.
135 */
136 static void serial_buf_free(struct circ_buf *cb)
137 {
138 kfree(cb->buf);
139 kfree(cb);
140 }
141
142 /*
143 * serial_buf_data_avail
144 *
145 * Return the number of bytes of data available in the circular
146 * buffer.
147 */
148 static int serial_buf_data_avail(struct circ_buf *cb)
149 {
150 return CIRC_CNT(cb->head, cb->tail, AIRCABLE_BUF_SIZE);
151 }
152
153 /*
154 * serial_buf_put
155 *
156 * Copy data data from a user buffer and put it into the circular buffer.
157 * Restrict to the amount of space available.
158 *
159 * Return the number of bytes copied.
160 */
161 static int serial_buf_put(struct circ_buf *cb, const char *buf, int count)
162 {
163 int c, ret = 0;
164 while (1) {
165 c = CIRC_SPACE_TO_END(cb->head, cb->tail, AIRCABLE_BUF_SIZE);
166 if (count < c)
167 c = count;
168 if (c <= 0)
169 break;
170 memcpy(cb->buf + cb->head, buf, c);
171 cb->head = (cb->head + c) & (AIRCABLE_BUF_SIZE-1);
172 buf += c;
173 count -= c;
174 ret = c;
175 }
176 return ret;
177 }
178
179 /*
180 * serial_buf_get
181 *
182 * Get data from the circular buffer and copy to the given buffer.
183 * Restrict to the amount of data available.
184 *
185 * Return the number of bytes copied.
186 */
187 static int serial_buf_get(struct circ_buf *cb, char *buf, int count)
188 {
189 int c, ret = 0;
190 while (1) {
191 c = CIRC_CNT_TO_END(cb->head, cb->tail, AIRCABLE_BUF_SIZE);
192 if (count < c)
193 c = count;
194 if (c <= 0)
195 break;
196 memcpy(buf, cb->buf + cb->tail, c);
197 cb->tail = (cb->tail + c) & (AIRCABLE_BUF_SIZE-1);
198 buf += c;
199 count -= c;
200 ret = c;
201 }
202 return ret;
203 }
204
205 /* End of circula buffer methods */
206
207 static void aircable_send(struct usb_serial_port *port)
208 {
209 int count, result;
210 struct aircable_private *priv = usb_get_serial_port_data(port);
211 unsigned char *buf;
212 __le16 *dbuf;
213 dbg("%s - port %d", __func__, port->number);
214 if (port->write_urb_busy)
215 return;
216
217 count = min(serial_buf_data_avail(priv->tx_buf), MAX_HCI_FRAMESIZE);
218 if (count == 0)
219 return;
220
221 buf = kzalloc(count + HCI_HEADER_LENGTH, GFP_ATOMIC);
222 if (!buf) {
223 dev_err(&port->dev, "%s- kzalloc(%d) failed.\n",
224 __func__, count + HCI_HEADER_LENGTH);
225 return;
226 }
227
228 buf[0] = TX_HEADER_0;
229 buf[1] = TX_HEADER_1;
230 dbuf = (__le16 *)&buf[2];
231 *dbuf = cpu_to_le16((u16)count);
232 serial_buf_get(priv->tx_buf, buf + HCI_HEADER_LENGTH,
233 MAX_HCI_FRAMESIZE);
234
235 memcpy(port->write_urb->transfer_buffer, buf,
236 count + HCI_HEADER_LENGTH);
237
238 kfree(buf);
239 port->write_urb_busy = 1;
240 usb_serial_debug_data(debug, &port->dev, __func__,
241 count + HCI_HEADER_LENGTH,
242 port->write_urb->transfer_buffer);
243 port->write_urb->transfer_buffer_length = count + HCI_HEADER_LENGTH;
244 port->write_urb->dev = port->serial->dev;
245 result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
246
247 if (result) {
248 dev_err(&port->dev,
249 "%s - failed submitting write urb, error %d\n",
250 __func__, result);
251 port->write_urb_busy = 0;
252 }
253
254 schedule_work(&port->work);
255 }
256
257 static void aircable_read(struct work_struct *work)
258 {
259 struct aircable_private *priv =
260 container_of(work, struct aircable_private, rx_work);
261 struct usb_serial_port *port = priv->port;
262 struct tty_struct *tty;
263 unsigned char *data;
264 int count;
265 if (priv->rx_flags & THROTTLED) {
266 if (priv->rx_flags & ACTUALLY_THROTTLED)
267 schedule_work(&priv->rx_work);
268 return;
269 }
270
271 /* By now I will flush data to the tty in packages of no more than
272 * 64 bytes, to ensure I do not get throttled.
273 * Ask USB mailing list for better aproach.
274 */
275 tty = tty_port_tty_get(&port->port);
276
277 if (!tty) {
278 schedule_work(&priv->rx_work);
279 dev_err(&port->dev, "%s - No tty available\n", __func__);
280 return ;
281 }
282
283 count = min(64, serial_buf_data_avail(priv->rx_buf));
284
285 if (count <= 0)
286 goto out; /* We have finished sending everything. */
287
288 tty_prepare_flip_string(tty, &data, count);
289 if (!data) {
290 dev_err(&port->dev, "%s- kzalloc(%d) failed.",
291 __func__, count);
292 goto out;
293 }
294
295 serial_buf_get(priv->rx_buf, data, count);
296
297 tty_flip_buffer_push(tty);
298
299 if (serial_buf_data_avail(priv->rx_buf))
300 schedule_work(&priv->rx_work);
301 out:
302 tty_kref_put(tty);
303 return;
304 }
305 /* End of private methods */
306
307 static int aircable_probe(struct usb_serial *serial,
308 const struct usb_device_id *id)
309 {
310 struct usb_host_interface *iface_desc = serial->interface->
311 cur_altsetting;
312 struct usb_endpoint_descriptor *endpoint;
313 int num_bulk_out = 0;
314 int i;
315
316 for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
317 endpoint = &iface_desc->endpoint[i].desc;
318 if (usb_endpoint_is_bulk_out(endpoint)) {
319 dbg("found bulk out on endpoint %d", i);
320 ++num_bulk_out;
321 }
322 }
323
324 if (num_bulk_out == 0) {
325 dbg("Invalid interface, discarding");
326 return -ENODEV;
327 }
328
329 return 0;
330 }
331
332 static int aircable_attach(struct usb_serial *serial)
333 {
334 struct usb_serial_port *port = serial->port[0];
335 struct aircable_private *priv;
336
337 priv = kzalloc(sizeof(struct aircable_private), GFP_KERNEL);
338 if (!priv) {
339 dev_err(&port->dev, "%s- kmalloc(%Zd) failed.\n", __func__,
340 sizeof(struct aircable_private));
341 return -ENOMEM;
342 }
343
344 /* Allocation of Circular Buffers */
345 priv->tx_buf = serial_buf_alloc();
346 if (priv->tx_buf == NULL) {
347 kfree(priv);
348 return -ENOMEM;
349 }
350
351 priv->rx_buf = serial_buf_alloc();
352 if (priv->rx_buf == NULL) {
353 kfree(priv->tx_buf);
354 kfree(priv);
355 return -ENOMEM;
356 }
357
358 priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED);
359 priv->port = port;
360 INIT_WORK(&priv->rx_work, aircable_read);
361
362 usb_set_serial_port_data(serial->port[0], priv);
363
364 return 0;
365 }
366
367 static void aircable_release(struct usb_serial *serial)
368 {
369
370 struct usb_serial_port *port = serial->port[0];
371 struct aircable_private *priv = usb_get_serial_port_data(port);
372
373 dbg("%s", __func__);
374
375 if (priv) {
376 serial_buf_free(priv->tx_buf);
377 serial_buf_free(priv->rx_buf);
378 kfree(priv);
379 }
380 }
381
382 static int aircable_write_room(struct tty_struct *tty)
383 {
384 struct usb_serial_port *port = tty->driver_data;
385 struct aircable_private *priv = usb_get_serial_port_data(port);
386 return serial_buf_data_avail(priv->tx_buf);
387 }
388
389 static int aircable_write(struct tty_struct *tty, struct usb_serial_port *port,
390 const unsigned char *source, int count)
391 {
392 struct aircable_private *priv = usb_get_serial_port_data(port);
393 int temp;
394
395 dbg("%s - port %d, %d bytes", __func__, port->number, count);
396
397 usb_serial_debug_data(debug, &port->dev, __func__, count, source);
398
399 if (!count) {
400 dbg("%s - write request of 0 bytes", __func__);
401 return count;
402 }
403
404 temp = serial_buf_put(priv->tx_buf, source, count);
405
406 aircable_send(port);
407
408 if (count > AIRCABLE_BUF_SIZE)
409 count = AIRCABLE_BUF_SIZE;
410
411 return count;
412
413 }
414
415 static void aircable_write_bulk_callback(struct urb *urb)
416 {
417 struct usb_serial_port *port = urb->context;
418 int status = urb->status;
419 int result;
420
421 dbg("%s - urb status: %d", __func__ , status);
422
423 /* This has been taken from cypress_m8.c cypress_write_int_callback */
424 switch (status) {
425 case 0:
426 /* success */
427 break;
428 case -ECONNRESET:
429 case -ENOENT:
430 case -ESHUTDOWN:
431 /* this urb is terminated, clean up */
432 dbg("%s - urb shutting down with status: %d",
433 __func__, status);
434 port->write_urb_busy = 0;
435 return;
436 default:
437 /* error in the urb, so we have to resubmit it */
438 dbg("%s - Overflow in write", __func__);
439 dbg("%s - nonzero write bulk status received: %d",
440 __func__, status);
441 port->write_urb->transfer_buffer_length = 1;
442 port->write_urb->dev = port->serial->dev;
443 result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
444 if (result)
445 dev_err(&urb->dev->dev,
446 "%s - failed resubmitting write urb, error %d\n",
447 __func__, result);
448 else
449 return;
450 }
451
452 port->write_urb_busy = 0;
453
454 aircable_send(port);
455 }
456
457 static void aircable_read_bulk_callback(struct urb *urb)
458 {
459 struct usb_serial_port *port = urb->context;
460 struct aircable_private *priv = usb_get_serial_port_data(port);
461 struct tty_struct *tty;
462 unsigned long no_packages, remaining, package_length, i;
463 int result, shift = 0;
464 unsigned char *temp;
465 int status = urb->status;
466
467 dbg("%s - port %d", __func__, port->number);
468
469 if (status) {
470 dbg("%s - urb status = %d", __func__, status);
471 if (!port->port.count) {
472 dbg("%s - port is closed, exiting.", __func__);
473 return;
474 }
475 if (status == -EPROTO) {
476 dbg("%s - caught -EPROTO, resubmitting the urb",
477 __func__);
478 usb_fill_bulk_urb(port->read_urb, port->serial->dev,
479 usb_rcvbulkpipe(port->serial->dev,
480 port->bulk_in_endpointAddress),
481 port->read_urb->transfer_buffer,
482 port->read_urb->transfer_buffer_length,
483 aircable_read_bulk_callback, port);
484
485 result = usb_submit_urb(urb, GFP_ATOMIC);
486 if (result)
487 dev_err(&urb->dev->dev,
488 "%s - failed resubmitting read urb, error %d\n",
489 __func__, result);
490 return;
491 }
492 dbg("%s - unable to handle the error, exiting.", __func__);
493 return;
494 }
495
496 usb_serial_debug_data(debug, &port->dev, __func__,
497 urb->actual_length, urb->transfer_buffer);
498
499 tty = tty_port_tty_get(&port->port);
500 if (tty && urb->actual_length) {
501 if (urb->actual_length <= 2) {
502 /* This is an incomplete package */
503 serial_buf_put(priv->rx_buf, urb->transfer_buffer,
504 urb->actual_length);
505 } else {
506 temp = urb->transfer_buffer;
507 if (temp[0] == RX_HEADER_0)
508 shift = HCI_HEADER_LENGTH;
509
510 remaining = urb->actual_length;
511 no_packages = urb->actual_length / (HCI_COMPLETE_FRAME);
512
513 if (urb->actual_length % HCI_COMPLETE_FRAME != 0)
514 no_packages++;
515
516 for (i = 0; i < no_packages; i++) {
517 if (remaining > (HCI_COMPLETE_FRAME))
518 package_length = HCI_COMPLETE_FRAME;
519 else
520 package_length = remaining;
521 remaining -= package_length;
522
523 serial_buf_put(priv->rx_buf,
524 urb->transfer_buffer + shift +
525 (HCI_COMPLETE_FRAME) * (i),
526 package_length - shift);
527 }
528 }
529 aircable_read(&priv->rx_work);
530 }
531 tty_kref_put(tty);
532
533 /* Schedule the next read _if_ we are still open */
534 if (port->port.count) {
535 usb_fill_bulk_urb(port->read_urb, port->serial->dev,
536 usb_rcvbulkpipe(port->serial->dev,
537 port->bulk_in_endpointAddress),
538 port->read_urb->transfer_buffer,
539 port->read_urb->transfer_buffer_length,
540 aircable_read_bulk_callback, port);
541
542 result = usb_submit_urb(urb, GFP_ATOMIC);
543 if (result)
544 dev_err(&urb->dev->dev,
545 "%s - failed resubmitting read urb, error %d\n",
546 __func__, result);
547 }
548
549 return;
550 }
551
552 /* Based on ftdi_sio.c throttle */
553 static void aircable_throttle(struct tty_struct *tty)
554 {
555 struct usb_serial_port *port = tty->driver_data;
556 struct aircable_private *priv = usb_get_serial_port_data(port);
557 unsigned long flags;
558
559 dbg("%s - port %d", __func__, port->number);
560
561 spin_lock_irqsave(&priv->rx_lock, flags);
562 priv->rx_flags |= THROTTLED;
563 spin_unlock_irqrestore(&priv->rx_lock, flags);
564 }
565
566 /* Based on ftdi_sio.c unthrottle */
567 static void aircable_unthrottle(struct tty_struct *tty)
568 {
569 struct usb_serial_port *port = tty->driver_data;
570 struct aircable_private *priv = usb_get_serial_port_data(port);
571 int actually_throttled;
572 unsigned long flags;
573
574 dbg("%s - port %d", __func__, port->number);
575
576 spin_lock_irqsave(&priv->rx_lock, flags);
577 actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED;
578 priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED);
579 spin_unlock_irqrestore(&priv->rx_lock, flags);
580
581 if (actually_throttled)
582 schedule_work(&priv->rx_work);
583 }
584
585 static struct usb_driver aircable_driver = {
586 .name = "aircable",
587 .probe = usb_serial_probe,
588 .disconnect = usb_serial_disconnect,
589 .id_table = id_table,
590 .no_dynamic_id = 1,
591 };
592
593 static struct usb_serial_driver aircable_device = {
594 .driver = {
595 .owner = THIS_MODULE,
596 .name = "aircable",
597 },
598 .usb_driver = &aircable_driver,
599 .id_table = id_table,
600 .num_ports = 1,
601 .attach = aircable_attach,
602 .probe = aircable_probe,
603 .release = aircable_release,
604 .write = aircable_write,
605 .write_room = aircable_write_room,
606 .write_bulk_callback = aircable_write_bulk_callback,
607 .read_bulk_callback = aircable_read_bulk_callback,
608 .throttle = aircable_throttle,
609 .unthrottle = aircable_unthrottle,
610 };
611
612 static int __init aircable_init(void)
613 {
614 int retval;
615 retval = usb_serial_register(&aircable_device);
616 if (retval)
617 goto failed_serial_register;
618 retval = usb_register(&aircable_driver);
619 if (retval)
620 goto failed_usb_register;
621 return 0;
622
623 failed_usb_register:
624 usb_serial_deregister(&aircable_device);
625 failed_serial_register:
626 return retval;
627 }
628
629 static void __exit aircable_exit(void)
630 {
631 usb_deregister(&aircable_driver);
632 usb_serial_deregister(&aircable_device);
633 }
634
635 MODULE_AUTHOR(DRIVER_AUTHOR);
636 MODULE_DESCRIPTION(DRIVER_DESC);
637 MODULE_VERSION(DRIVER_VERSION);
638 MODULE_LICENSE("GPL");
639
640 module_init(aircable_init);
641 module_exit(aircable_exit);
642
643 module_param(debug, bool, S_IRUGO | S_IWUSR);
644 MODULE_PARM_DESC(debug, "Debug enabled or not");
645
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