xref: /openbmc/linux/drivers/bluetooth/hci_ldisc.c (revision d2999e1b)
1 /*
2  *
3  *  Bluetooth HCI UART driver
4  *
5  *  Copyright (C) 2000-2001  Qualcomm Incorporated
6  *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
7  *  Copyright (C) 2004-2005  Marcel Holtmann <marcel@holtmann.org>
8  *
9  *
10  *  This program is free software; you can redistribute it and/or modify
11  *  it under the terms of the GNU General Public License as published by
12  *  the Free Software Foundation; either version 2 of the License, or
13  *  (at your option) any later version.
14  *
15  *  This program is distributed in the hope that it will be useful,
16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  *  GNU General Public License for more details.
19  *
20  *  You should have received a copy of the GNU General Public License
21  *  along with this program; if not, write to the Free Software
22  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
23  *
24  */
25 
26 #include <linux/module.h>
27 
28 #include <linux/kernel.h>
29 #include <linux/init.h>
30 #include <linux/types.h>
31 #include <linux/fcntl.h>
32 #include <linux/interrupt.h>
33 #include <linux/ptrace.h>
34 #include <linux/poll.h>
35 
36 #include <linux/slab.h>
37 #include <linux/tty.h>
38 #include <linux/errno.h>
39 #include <linux/string.h>
40 #include <linux/signal.h>
41 #include <linux/ioctl.h>
42 #include <linux/skbuff.h>
43 
44 #include <net/bluetooth/bluetooth.h>
45 #include <net/bluetooth/hci_core.h>
46 
47 #include "hci_uart.h"
48 
49 #define VERSION "2.2"
50 
51 static struct hci_uart_proto *hup[HCI_UART_MAX_PROTO];
52 
53 int hci_uart_register_proto(struct hci_uart_proto *p)
54 {
55 	if (p->id >= HCI_UART_MAX_PROTO)
56 		return -EINVAL;
57 
58 	if (hup[p->id])
59 		return -EEXIST;
60 
61 	hup[p->id] = p;
62 
63 	return 0;
64 }
65 
66 int hci_uart_unregister_proto(struct hci_uart_proto *p)
67 {
68 	if (p->id >= HCI_UART_MAX_PROTO)
69 		return -EINVAL;
70 
71 	if (!hup[p->id])
72 		return -EINVAL;
73 
74 	hup[p->id] = NULL;
75 
76 	return 0;
77 }
78 
79 static struct hci_uart_proto *hci_uart_get_proto(unsigned int id)
80 {
81 	if (id >= HCI_UART_MAX_PROTO)
82 		return NULL;
83 
84 	return hup[id];
85 }
86 
87 static inline void hci_uart_tx_complete(struct hci_uart *hu, int pkt_type)
88 {
89 	struct hci_dev *hdev = hu->hdev;
90 
91 	/* Update HCI stat counters */
92 	switch (pkt_type) {
93 	case HCI_COMMAND_PKT:
94 		hdev->stat.cmd_tx++;
95 		break;
96 
97 	case HCI_ACLDATA_PKT:
98 		hdev->stat.acl_tx++;
99 		break;
100 
101 	case HCI_SCODATA_PKT:
102 		hdev->stat.sco_tx++;
103 		break;
104 	}
105 }
106 
107 static inline struct sk_buff *hci_uart_dequeue(struct hci_uart *hu)
108 {
109 	struct sk_buff *skb = hu->tx_skb;
110 
111 	if (!skb)
112 		skb = hu->proto->dequeue(hu);
113 	else
114 		hu->tx_skb = NULL;
115 
116 	return skb;
117 }
118 
119 int hci_uart_tx_wakeup(struct hci_uart *hu)
120 {
121 	if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) {
122 		set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
123 		return 0;
124 	}
125 
126 	BT_DBG("");
127 
128 	schedule_work(&hu->write_work);
129 
130 	return 0;
131 }
132 
133 static void hci_uart_write_work(struct work_struct *work)
134 {
135 	struct hci_uart *hu = container_of(work, struct hci_uart, write_work);
136 	struct tty_struct *tty = hu->tty;
137 	struct hci_dev *hdev = hu->hdev;
138 	struct sk_buff *skb;
139 
140 	/* REVISIT: should we cope with bad skbs or ->write() returning
141 	 * and error value ?
142 	 */
143 
144 restart:
145 	clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
146 
147 	while ((skb = hci_uart_dequeue(hu))) {
148 		int len;
149 
150 		set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
151 		len = tty->ops->write(tty, skb->data, skb->len);
152 		hdev->stat.byte_tx += len;
153 
154 		skb_pull(skb, len);
155 		if (skb->len) {
156 			hu->tx_skb = skb;
157 			break;
158 		}
159 
160 		hci_uart_tx_complete(hu, bt_cb(skb)->pkt_type);
161 		kfree_skb(skb);
162 	}
163 
164 	if (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state))
165 		goto restart;
166 
167 	clear_bit(HCI_UART_SENDING, &hu->tx_state);
168 }
169 
170 static void hci_uart_init_work(struct work_struct *work)
171 {
172 	struct hci_uart *hu = container_of(work, struct hci_uart, init_ready);
173 	int err;
174 
175 	if (!test_and_clear_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
176 		return;
177 
178 	err = hci_register_dev(hu->hdev);
179 	if (err < 0) {
180 		BT_ERR("Can't register HCI device");
181 		hci_free_dev(hu->hdev);
182 		hu->hdev = NULL;
183 		hu->proto->close(hu);
184 	}
185 
186 	set_bit(HCI_UART_REGISTERED, &hu->flags);
187 }
188 
189 int hci_uart_init_ready(struct hci_uart *hu)
190 {
191 	if (!test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
192 		return -EALREADY;
193 
194 	schedule_work(&hu->init_ready);
195 
196 	return 0;
197 }
198 
199 /* ------- Interface to HCI layer ------ */
200 /* Initialize device */
201 static int hci_uart_open(struct hci_dev *hdev)
202 {
203 	BT_DBG("%s %p", hdev->name, hdev);
204 
205 	/* Nothing to do for UART driver */
206 
207 	set_bit(HCI_RUNNING, &hdev->flags);
208 
209 	return 0;
210 }
211 
212 /* Reset device */
213 static int hci_uart_flush(struct hci_dev *hdev)
214 {
215 	struct hci_uart *hu  = hci_get_drvdata(hdev);
216 	struct tty_struct *tty = hu->tty;
217 
218 	BT_DBG("hdev %p tty %p", hdev, tty);
219 
220 	if (hu->tx_skb) {
221 		kfree_skb(hu->tx_skb); hu->tx_skb = NULL;
222 	}
223 
224 	/* Flush any pending characters in the driver and discipline. */
225 	tty_ldisc_flush(tty);
226 	tty_driver_flush_buffer(tty);
227 
228 	if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
229 		hu->proto->flush(hu);
230 
231 	return 0;
232 }
233 
234 /* Close device */
235 static int hci_uart_close(struct hci_dev *hdev)
236 {
237 	BT_DBG("hdev %p", hdev);
238 
239 	if (!test_and_clear_bit(HCI_RUNNING, &hdev->flags))
240 		return 0;
241 
242 	hci_uart_flush(hdev);
243 	hdev->flush = NULL;
244 	return 0;
245 }
246 
247 /* Send frames from HCI layer */
248 static int hci_uart_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
249 {
250 	struct hci_uart *hu = hci_get_drvdata(hdev);
251 
252 	if (!test_bit(HCI_RUNNING, &hdev->flags))
253 		return -EBUSY;
254 
255 	BT_DBG("%s: type %d len %d", hdev->name, bt_cb(skb)->pkt_type, skb->len);
256 
257 	hu->proto->enqueue(hu, skb);
258 
259 	hci_uart_tx_wakeup(hu);
260 
261 	return 0;
262 }
263 
264 /* ------ LDISC part ------ */
265 /* hci_uart_tty_open
266  *
267  *     Called when line discipline changed to HCI_UART.
268  *
269  * Arguments:
270  *     tty    pointer to tty info structure
271  * Return Value:
272  *     0 if success, otherwise error code
273  */
274 static int hci_uart_tty_open(struct tty_struct *tty)
275 {
276 	struct hci_uart *hu;
277 
278 	BT_DBG("tty %p", tty);
279 
280 	/* Error if the tty has no write op instead of leaving an exploitable
281 	   hole */
282 	if (tty->ops->write == NULL)
283 		return -EOPNOTSUPP;
284 
285 	hu = kzalloc(sizeof(struct hci_uart), GFP_KERNEL);
286 	if (!hu) {
287 		BT_ERR("Can't allocate control structure");
288 		return -ENFILE;
289 	}
290 
291 	tty->disc_data = hu;
292 	hu->tty = tty;
293 	tty->receive_room = 65536;
294 
295 	INIT_WORK(&hu->init_ready, hci_uart_init_work);
296 	INIT_WORK(&hu->write_work, hci_uart_write_work);
297 
298 	spin_lock_init(&hu->rx_lock);
299 
300 	/* Flush any pending characters in the driver and line discipline. */
301 
302 	/* FIXME: why is this needed. Note don't use ldisc_ref here as the
303 	   open path is before the ldisc is referencable */
304 
305 	if (tty->ldisc->ops->flush_buffer)
306 		tty->ldisc->ops->flush_buffer(tty);
307 	tty_driver_flush_buffer(tty);
308 
309 	return 0;
310 }
311 
312 /* hci_uart_tty_close()
313  *
314  *    Called when the line discipline is changed to something
315  *    else, the tty is closed, or the tty detects a hangup.
316  */
317 static void hci_uart_tty_close(struct tty_struct *tty)
318 {
319 	struct hci_uart *hu = (void *)tty->disc_data;
320 	struct hci_dev *hdev;
321 
322 	BT_DBG("tty %p", tty);
323 
324 	/* Detach from the tty */
325 	tty->disc_data = NULL;
326 
327 	if (!hu)
328 		return;
329 
330 	hdev = hu->hdev;
331 	if (hdev)
332 		hci_uart_close(hdev);
333 
334 	cancel_work_sync(&hu->write_work);
335 
336 	if (test_and_clear_bit(HCI_UART_PROTO_SET, &hu->flags)) {
337 		if (hdev) {
338 			if (test_bit(HCI_UART_REGISTERED, &hu->flags))
339 				hci_unregister_dev(hdev);
340 			hci_free_dev(hdev);
341 		}
342 		hu->proto->close(hu);
343 	}
344 
345 	kfree(hu);
346 }
347 
348 /* hci_uart_tty_wakeup()
349  *
350  *    Callback for transmit wakeup. Called when low level
351  *    device driver can accept more send data.
352  *
353  * Arguments:        tty    pointer to associated tty instance data
354  * Return Value:    None
355  */
356 static void hci_uart_tty_wakeup(struct tty_struct *tty)
357 {
358 	struct hci_uart *hu = (void *)tty->disc_data;
359 
360 	BT_DBG("");
361 
362 	if (!hu)
363 		return;
364 
365 	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
366 
367 	if (tty != hu->tty)
368 		return;
369 
370 	if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
371 		hci_uart_tx_wakeup(hu);
372 }
373 
374 /* hci_uart_tty_receive()
375  *
376  *     Called by tty low level driver when receive data is
377  *     available.
378  *
379  * Arguments:  tty          pointer to tty isntance data
380  *             data         pointer to received data
381  *             flags        pointer to flags for data
382  *             count        count of received data in bytes
383  *
384  * Return Value:    None
385  */
386 static void hci_uart_tty_receive(struct tty_struct *tty, const u8 *data, char *flags, int count)
387 {
388 	struct hci_uart *hu = (void *)tty->disc_data;
389 
390 	if (!hu || tty != hu->tty)
391 		return;
392 
393 	if (!test_bit(HCI_UART_PROTO_SET, &hu->flags))
394 		return;
395 
396 	spin_lock(&hu->rx_lock);
397 	hu->proto->recv(hu, (void *) data, count);
398 
399 	if (hu->hdev)
400 		hu->hdev->stat.byte_rx += count;
401 
402 	spin_unlock(&hu->rx_lock);
403 
404 	tty_unthrottle(tty);
405 }
406 
407 static int hci_uart_register_dev(struct hci_uart *hu)
408 {
409 	struct hci_dev *hdev;
410 
411 	BT_DBG("");
412 
413 	/* Initialize and register HCI device */
414 	hdev = hci_alloc_dev();
415 	if (!hdev) {
416 		BT_ERR("Can't allocate HCI device");
417 		return -ENOMEM;
418 	}
419 
420 	hu->hdev = hdev;
421 
422 	hdev->bus = HCI_UART;
423 	hci_set_drvdata(hdev, hu);
424 
425 	hdev->open  = hci_uart_open;
426 	hdev->close = hci_uart_close;
427 	hdev->flush = hci_uart_flush;
428 	hdev->send  = hci_uart_send_frame;
429 	SET_HCIDEV_DEV(hdev, hu->tty->dev);
430 
431 	if (test_bit(HCI_UART_RAW_DEVICE, &hu->hdev_flags))
432 		set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
433 
434 	if (!test_bit(HCI_UART_RESET_ON_INIT, &hu->hdev_flags))
435 		set_bit(HCI_QUIRK_RESET_ON_CLOSE, &hdev->quirks);
436 
437 	if (test_bit(HCI_UART_CREATE_AMP, &hu->hdev_flags))
438 		hdev->dev_type = HCI_AMP;
439 	else
440 		hdev->dev_type = HCI_BREDR;
441 
442 	if (test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
443 		return 0;
444 
445 	if (hci_register_dev(hdev) < 0) {
446 		BT_ERR("Can't register HCI device");
447 		hci_free_dev(hdev);
448 		return -ENODEV;
449 	}
450 
451 	set_bit(HCI_UART_REGISTERED, &hu->flags);
452 
453 	return 0;
454 }
455 
456 static int hci_uart_set_proto(struct hci_uart *hu, int id)
457 {
458 	struct hci_uart_proto *p;
459 	int err;
460 
461 	p = hci_uart_get_proto(id);
462 	if (!p)
463 		return -EPROTONOSUPPORT;
464 
465 	err = p->open(hu);
466 	if (err)
467 		return err;
468 
469 	hu->proto = p;
470 
471 	err = hci_uart_register_dev(hu);
472 	if (err) {
473 		p->close(hu);
474 		return err;
475 	}
476 
477 	return 0;
478 }
479 
480 /* hci_uart_tty_ioctl()
481  *
482  *    Process IOCTL system call for the tty device.
483  *
484  * Arguments:
485  *
486  *    tty        pointer to tty instance data
487  *    file       pointer to open file object for device
488  *    cmd        IOCTL command code
489  *    arg        argument for IOCTL call (cmd dependent)
490  *
491  * Return Value:    Command dependent
492  */
493 static int hci_uart_tty_ioctl(struct tty_struct *tty, struct file * file,
494 					unsigned int cmd, unsigned long arg)
495 {
496 	struct hci_uart *hu = (void *)tty->disc_data;
497 	int err = 0;
498 
499 	BT_DBG("");
500 
501 	/* Verify the status of the device */
502 	if (!hu)
503 		return -EBADF;
504 
505 	switch (cmd) {
506 	case HCIUARTSETPROTO:
507 		if (!test_and_set_bit(HCI_UART_PROTO_SET, &hu->flags)) {
508 			err = hci_uart_set_proto(hu, arg);
509 			if (err) {
510 				clear_bit(HCI_UART_PROTO_SET, &hu->flags);
511 				return err;
512 			}
513 		} else
514 			return -EBUSY;
515 		break;
516 
517 	case HCIUARTGETPROTO:
518 		if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
519 			return hu->proto->id;
520 		return -EUNATCH;
521 
522 	case HCIUARTGETDEVICE:
523 		if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
524 			return hu->hdev->id;
525 		return -EUNATCH;
526 
527 	case HCIUARTSETFLAGS:
528 		if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
529 			return -EBUSY;
530 		hu->hdev_flags = arg;
531 		break;
532 
533 	case HCIUARTGETFLAGS:
534 		return hu->hdev_flags;
535 
536 	default:
537 		err = n_tty_ioctl_helper(tty, file, cmd, arg);
538 		break;
539 	}
540 
541 	return err;
542 }
543 
544 /*
545  * We don't provide read/write/poll interface for user space.
546  */
547 static ssize_t hci_uart_tty_read(struct tty_struct *tty, struct file *file,
548 					unsigned char __user *buf, size_t nr)
549 {
550 	return 0;
551 }
552 
553 static ssize_t hci_uart_tty_write(struct tty_struct *tty, struct file *file,
554 					const unsigned char *data, size_t count)
555 {
556 	return 0;
557 }
558 
559 static unsigned int hci_uart_tty_poll(struct tty_struct *tty,
560 					struct file *filp, poll_table *wait)
561 {
562 	return 0;
563 }
564 
565 static int __init hci_uart_init(void)
566 {
567 	static struct tty_ldisc_ops hci_uart_ldisc;
568 	int err;
569 
570 	BT_INFO("HCI UART driver ver %s", VERSION);
571 
572 	/* Register the tty discipline */
573 
574 	memset(&hci_uart_ldisc, 0, sizeof (hci_uart_ldisc));
575 	hci_uart_ldisc.magic		= TTY_LDISC_MAGIC;
576 	hci_uart_ldisc.name		= "n_hci";
577 	hci_uart_ldisc.open		= hci_uart_tty_open;
578 	hci_uart_ldisc.close		= hci_uart_tty_close;
579 	hci_uart_ldisc.read		= hci_uart_tty_read;
580 	hci_uart_ldisc.write		= hci_uart_tty_write;
581 	hci_uart_ldisc.ioctl		= hci_uart_tty_ioctl;
582 	hci_uart_ldisc.poll		= hci_uart_tty_poll;
583 	hci_uart_ldisc.receive_buf	= hci_uart_tty_receive;
584 	hci_uart_ldisc.write_wakeup	= hci_uart_tty_wakeup;
585 	hci_uart_ldisc.owner		= THIS_MODULE;
586 
587 	err = tty_register_ldisc(N_HCI, &hci_uart_ldisc);
588 	if (err) {
589 		BT_ERR("HCI line discipline registration failed. (%d)", err);
590 		return err;
591 	}
592 
593 #ifdef CONFIG_BT_HCIUART_H4
594 	h4_init();
595 #endif
596 #ifdef CONFIG_BT_HCIUART_BCSP
597 	bcsp_init();
598 #endif
599 #ifdef CONFIG_BT_HCIUART_LL
600 	ll_init();
601 #endif
602 #ifdef CONFIG_BT_HCIUART_ATH3K
603 	ath_init();
604 #endif
605 #ifdef CONFIG_BT_HCIUART_3WIRE
606 	h5_init();
607 #endif
608 
609 	return 0;
610 }
611 
612 static void __exit hci_uart_exit(void)
613 {
614 	int err;
615 
616 #ifdef CONFIG_BT_HCIUART_H4
617 	h4_deinit();
618 #endif
619 #ifdef CONFIG_BT_HCIUART_BCSP
620 	bcsp_deinit();
621 #endif
622 #ifdef CONFIG_BT_HCIUART_LL
623 	ll_deinit();
624 #endif
625 #ifdef CONFIG_BT_HCIUART_ATH3K
626 	ath_deinit();
627 #endif
628 #ifdef CONFIG_BT_HCIUART_3WIRE
629 	h5_deinit();
630 #endif
631 
632 	/* Release tty registration of line discipline */
633 	err = tty_unregister_ldisc(N_HCI);
634 	if (err)
635 		BT_ERR("Can't unregister HCI line discipline (%d)", err);
636 }
637 
638 module_init(hci_uart_init);
639 module_exit(hci_uart_exit);
640 
641 MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
642 MODULE_DESCRIPTION("Bluetooth HCI UART driver ver " VERSION);
643 MODULE_VERSION(VERSION);
644 MODULE_LICENSE("GPL");
645 MODULE_ALIAS_LDISC(N_HCI);
646