xref: /linux/drivers/bluetooth/hci_ldisc.c (revision 985d4a55e64e43bd86eeb896b81ceba453301989)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *
4  *  Bluetooth HCI UART driver
5  *
6  *  Copyright (C) 2000-2001  Qualcomm Incorporated
7  *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
8  *  Copyright (C) 2004-2005  Marcel Holtmann <marcel@holtmann.org>
9  */
10 
11 #include <linux/module.h>
12 
13 #include <linux/kernel.h>
14 #include <linux/init.h>
15 #include <linux/types.h>
16 #include <linux/fcntl.h>
17 #include <linux/interrupt.h>
18 #include <linux/ptrace.h>
19 #include <linux/poll.h>
20 
21 #include <linux/slab.h>
22 #include <linux/tty.h>
23 #include <linux/errno.h>
24 #include <linux/string.h>
25 #include <linux/signal.h>
26 #include <linux/ioctl.h>
27 #include <linux/skbuff.h>
28 #include <linux/firmware.h>
29 #include <linux/serdev.h>
30 
31 #include <net/bluetooth/bluetooth.h>
32 #include <net/bluetooth/hci_core.h>
33 
34 #include "btintel.h"
35 #include "btbcm.h"
36 #include "hci_uart.h"
37 
38 #define VERSION "2.3"
39 
40 static const struct hci_uart_proto *hup[HCI_UART_MAX_PROTO];
41 
42 int hci_uart_register_proto(const struct hci_uart_proto *p)
43 {
44 	if (p->id >= HCI_UART_MAX_PROTO)
45 		return -EINVAL;
46 
47 	if (hup[p->id])
48 		return -EEXIST;
49 
50 	hup[p->id] = p;
51 
52 	BT_INFO("HCI UART protocol %s registered", p->name);
53 
54 	return 0;
55 }
56 
57 int hci_uart_unregister_proto(const struct hci_uart_proto *p)
58 {
59 	if (p->id >= HCI_UART_MAX_PROTO)
60 		return -EINVAL;
61 
62 	if (!hup[p->id])
63 		return -EINVAL;
64 
65 	hup[p->id] = NULL;
66 
67 	return 0;
68 }
69 
70 static const struct hci_uart_proto *hci_uart_get_proto(unsigned int id)
71 {
72 	if (id >= HCI_UART_MAX_PROTO)
73 		return NULL;
74 
75 	return hup[id];
76 }
77 
78 static inline void hci_uart_tx_complete(struct hci_uart *hu, int pkt_type)
79 {
80 	struct hci_dev *hdev = hu->hdev;
81 
82 	/* Update HCI stat counters */
83 	switch (pkt_type) {
84 	case HCI_COMMAND_PKT:
85 		hdev->stat.cmd_tx++;
86 		break;
87 
88 	case HCI_ACLDATA_PKT:
89 		hdev->stat.acl_tx++;
90 		break;
91 
92 	case HCI_SCODATA_PKT:
93 		hdev->stat.sco_tx++;
94 		break;
95 	}
96 }
97 
98 static inline struct sk_buff *hci_uart_dequeue(struct hci_uart *hu)
99 {
100 	struct sk_buff *skb = hu->tx_skb;
101 
102 	if (!skb) {
103 		percpu_down_read(&hu->proto_lock);
104 
105 		if (test_bit(HCI_UART_PROTO_READY, &hu->flags) ||
106 		    test_bit(HCI_UART_PROTO_INIT, &hu->flags))
107 			skb = hu->proto->dequeue(hu);
108 
109 		percpu_up_read(&hu->proto_lock);
110 	} else {
111 		hu->tx_skb = NULL;
112 	}
113 
114 	return skb;
115 }
116 
117 int hci_uart_tx_wakeup(struct hci_uart *hu)
118 {
119 	/* This may be called in an IRQ context, so we can't sleep. Therefore
120 	 * we try to acquire the lock only, and if that fails we assume the
121 	 * tty is being closed because that is the only time the write lock is
122 	 * acquired. If, however, at some point in the future the write lock
123 	 * is also acquired in other situations, then this must be revisited.
124 	 */
125 	if (!percpu_down_read_trylock(&hu->proto_lock))
126 		return 0;
127 
128 	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags) &&
129 	    !test_bit(HCI_UART_PROTO_INIT, &hu->flags))
130 		goto no_schedule;
131 
132 	set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
133 	if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state))
134 		goto no_schedule;
135 
136 	BT_DBG("");
137 
138 	schedule_work(&hu->write_work);
139 
140 no_schedule:
141 	percpu_up_read(&hu->proto_lock);
142 
143 	return 0;
144 }
145 EXPORT_SYMBOL_GPL(hci_uart_tx_wakeup);
146 
147 static void hci_uart_write_work(struct work_struct *work)
148 {
149 	struct hci_uart *hu = container_of(work, struct hci_uart, write_work);
150 	struct tty_struct *tty = hu->tty;
151 	struct hci_dev *hdev = hu->hdev;
152 	struct sk_buff *skb;
153 
154 	/* REVISIT: should we cope with bad skbs or ->write() returning
155 	 * and error value ?
156 	 */
157 
158 restart:
159 	clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
160 
161 	while ((skb = hci_uart_dequeue(hu))) {
162 		int len;
163 
164 		set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
165 		len = tty->ops->write(tty, skb->data, skb->len);
166 		hdev->stat.byte_tx += len;
167 
168 		skb_pull(skb, len);
169 		if (skb->len) {
170 			hu->tx_skb = skb;
171 			break;
172 		}
173 
174 		hci_uart_tx_complete(hu, hci_skb_pkt_type(skb));
175 		kfree_skb(skb);
176 	}
177 
178 	clear_bit(HCI_UART_SENDING, &hu->tx_state);
179 	if (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state))
180 		goto restart;
181 
182 	wake_up_bit(&hu->tx_state, HCI_UART_SENDING);
183 }
184 
185 void hci_uart_init_work(struct work_struct *work)
186 {
187 	struct hci_uart *hu = container_of(work, struct hci_uart, init_ready);
188 	int err;
189 	struct hci_dev *hdev;
190 
191 	if (!test_and_clear_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
192 		return;
193 
194 	err = hci_register_dev(hu->hdev);
195 	if (err < 0) {
196 		BT_ERR("Can't register HCI device");
197 
198 		percpu_down_write(&hu->proto_lock);
199 		clear_bit(HCI_UART_PROTO_READY, &hu->flags);
200 		percpu_up_write(&hu->proto_lock);
201 
202 		/* Safely cancel work after clearing flags */
203 		cancel_work_sync(&hu->write_work);
204 
205 		/* Close protocol before freeing hdev */
206 		hu->proto->close(hu);
207 		hdev = hu->hdev;
208 		hu->hdev = NULL;
209 		hci_free_dev(hdev);
210 		return;
211 	}
212 
213 	set_bit(HCI_UART_REGISTERED, &hu->flags);
214 }
215 
216 int hci_uart_init_ready(struct hci_uart *hu)
217 {
218 	if (!test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
219 		return -EALREADY;
220 
221 	schedule_work(&hu->init_ready);
222 
223 	return 0;
224 }
225 
226 int hci_uart_wait_until_sent(struct hci_uart *hu)
227 {
228 	return wait_on_bit_timeout(&hu->tx_state, HCI_UART_SENDING,
229 				   TASK_INTERRUPTIBLE,
230 				   msecs_to_jiffies(2000));
231 }
232 
233 /* ------- Interface to HCI layer ------ */
234 /* Reset device */
235 static int hci_uart_flush(struct hci_dev *hdev)
236 {
237 	struct hci_uart *hu  = hci_get_drvdata(hdev);
238 	struct tty_struct *tty = hu->tty;
239 
240 	BT_DBG("hdev %p tty %p", hdev, tty);
241 
242 	if (hu->tx_skb) {
243 		kfree_skb(hu->tx_skb); hu->tx_skb = NULL;
244 	}
245 
246 	/* Flush any pending characters in the driver and discipline. */
247 	tty_ldisc_flush(tty);
248 	tty_driver_flush_buffer(tty);
249 
250 	percpu_down_read(&hu->proto_lock);
251 
252 	if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
253 		hu->proto->flush(hu);
254 
255 	percpu_up_read(&hu->proto_lock);
256 
257 	return 0;
258 }
259 
260 /* Initialize device */
261 static int hci_uart_open(struct hci_dev *hdev)
262 {
263 	BT_DBG("%s %p", hdev->name, hdev);
264 
265 	/* Undo clearing this from hci_uart_close() */
266 	hdev->flush = hci_uart_flush;
267 
268 	return 0;
269 }
270 
271 /* Close device */
272 static int hci_uart_close(struct hci_dev *hdev)
273 {
274 	struct hci_uart *hu = hci_get_drvdata(hdev);
275 
276 	BT_DBG("hdev %p", hdev);
277 
278 	cancel_work_sync(&hu->write_work);
279 
280 	hci_uart_flush(hdev);
281 	hdev->flush = NULL;
282 	return 0;
283 }
284 
285 /* Send frames from HCI layer */
286 static int hci_uart_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
287 {
288 	struct hci_uart *hu = hci_get_drvdata(hdev);
289 
290 	BT_DBG("%s: type %d len %d", hdev->name, hci_skb_pkt_type(skb),
291 	       skb->len);
292 
293 	percpu_down_read(&hu->proto_lock);
294 
295 	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags) &&
296 	    !test_bit(HCI_UART_PROTO_INIT, &hu->flags)) {
297 		percpu_up_read(&hu->proto_lock);
298 		return -EUNATCH;
299 	}
300 
301 	hu->proto->enqueue(hu, skb);
302 	percpu_up_read(&hu->proto_lock);
303 
304 	hci_uart_tx_wakeup(hu);
305 
306 	return 0;
307 }
308 
309 /* Check the underlying device or tty has flow control support */
310 bool hci_uart_has_flow_control(struct hci_uart *hu)
311 {
312 	/* serdev nodes check if the needed operations are present */
313 	if (hu->serdev)
314 		return true;
315 
316 	if (hu->tty->driver->ops->tiocmget && hu->tty->driver->ops->tiocmset)
317 		return true;
318 
319 	return false;
320 }
321 
322 /* Flow control or un-flow control the device */
323 void hci_uart_set_flow_control(struct hci_uart *hu, bool enable)
324 {
325 	struct tty_struct *tty = hu->tty;
326 	struct ktermios ktermios;
327 	int status;
328 	unsigned int set = 0;
329 	unsigned int clear = 0;
330 
331 	if (hu->serdev) {
332 		serdev_device_set_flow_control(hu->serdev, !enable);
333 		serdev_device_set_rts(hu->serdev, !enable);
334 		return;
335 	}
336 
337 	if (enable) {
338 		/* Disable hardware flow control */
339 		ktermios = tty->termios;
340 		ktermios.c_cflag &= ~CRTSCTS;
341 		tty_set_termios(tty, &ktermios);
342 		BT_DBG("Disabling hardware flow control: %s",
343 		       (tty->termios.c_cflag & CRTSCTS) ? "failed" : "success");
344 
345 		/* Clear RTS to prevent the device from sending */
346 		/* Most UARTs need OUT2 to enable interrupts */
347 		status = tty->driver->ops->tiocmget(tty);
348 		BT_DBG("Current tiocm 0x%x", status);
349 
350 		set &= ~(TIOCM_OUT2 | TIOCM_RTS);
351 		clear = ~set;
352 		set &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
353 		       TIOCM_OUT2 | TIOCM_LOOP;
354 		clear &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
355 			 TIOCM_OUT2 | TIOCM_LOOP;
356 		status = tty->driver->ops->tiocmset(tty, set, clear);
357 		BT_DBG("Clearing RTS: %s", status ? "failed" : "success");
358 	} else {
359 		/* Set RTS to allow the device to send again */
360 		status = tty->driver->ops->tiocmget(tty);
361 		BT_DBG("Current tiocm 0x%x", status);
362 
363 		set |= (TIOCM_OUT2 | TIOCM_RTS);
364 		clear = ~set;
365 		set &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
366 		       TIOCM_OUT2 | TIOCM_LOOP;
367 		clear &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
368 			 TIOCM_OUT2 | TIOCM_LOOP;
369 		status = tty->driver->ops->tiocmset(tty, set, clear);
370 		BT_DBG("Setting RTS: %s", status ? "failed" : "success");
371 
372 		/* Re-enable hardware flow control */
373 		ktermios = tty->termios;
374 		ktermios.c_cflag |= CRTSCTS;
375 		tty_set_termios(tty, &ktermios);
376 		BT_DBG("Enabling hardware flow control: %s",
377 		       !(tty->termios.c_cflag & CRTSCTS) ? "failed" : "success");
378 	}
379 }
380 
381 void hci_uart_set_speeds(struct hci_uart *hu, unsigned int init_speed,
382 			 unsigned int oper_speed)
383 {
384 	hu->init_speed = init_speed;
385 	hu->oper_speed = oper_speed;
386 }
387 
388 void hci_uart_set_baudrate(struct hci_uart *hu, unsigned int speed)
389 {
390 	struct tty_struct *tty = hu->tty;
391 	struct ktermios ktermios;
392 
393 	ktermios = tty->termios;
394 	ktermios.c_cflag &= ~CBAUD;
395 	tty_termios_encode_baud_rate(&ktermios, speed, speed);
396 
397 	/* tty_set_termios() return not checked as it is always 0 */
398 	tty_set_termios(tty, &ktermios);
399 
400 	BT_DBG("%s: New tty speeds: %d/%d", hu->hdev->name,
401 	       tty->termios.c_ispeed, tty->termios.c_ospeed);
402 }
403 
404 static int hci_uart_setup(struct hci_dev *hdev)
405 {
406 	struct hci_uart *hu = hci_get_drvdata(hdev);
407 	struct hci_rp_read_local_version *ver;
408 	struct sk_buff *skb;
409 	unsigned int speed;
410 	int err;
411 
412 	/* Init speed if any */
413 	if (hu->init_speed)
414 		speed = hu->init_speed;
415 	else if (hu->proto->init_speed)
416 		speed = hu->proto->init_speed;
417 	else
418 		speed = 0;
419 
420 	if (speed)
421 		hci_uart_set_baudrate(hu, speed);
422 
423 	/* Operational speed if any */
424 	if (hu->oper_speed)
425 		speed = hu->oper_speed;
426 	else if (hu->proto->oper_speed)
427 		speed = hu->proto->oper_speed;
428 	else
429 		speed = 0;
430 
431 	if (hu->proto->set_baudrate && speed) {
432 		err = hu->proto->set_baudrate(hu, speed);
433 		if (!err)
434 			hci_uart_set_baudrate(hu, speed);
435 	}
436 
437 	if (hu->proto->setup)
438 		return hu->proto->setup(hu);
439 
440 	if (!test_bit(HCI_UART_VND_DETECT, &hu->hdev_flags))
441 		return 0;
442 
443 	skb = __hci_cmd_sync(hdev, HCI_OP_READ_LOCAL_VERSION, 0, NULL,
444 			     HCI_INIT_TIMEOUT);
445 	if (IS_ERR(skb)) {
446 		BT_ERR("%s: Reading local version information failed (%ld)",
447 		       hdev->name, PTR_ERR(skb));
448 		return 0;
449 	}
450 
451 	if (skb->len != sizeof(*ver)) {
452 		BT_ERR("%s: Event length mismatch for version information",
453 		       hdev->name);
454 		goto done;
455 	}
456 
457 	ver = (struct hci_rp_read_local_version *)skb->data;
458 
459 	switch (le16_to_cpu(ver->manufacturer)) {
460 #ifdef CONFIG_BT_HCIUART_INTEL
461 	case 2:
462 		hdev->set_bdaddr = btintel_set_bdaddr;
463 		btintel_check_bdaddr(hdev);
464 		break;
465 #endif
466 #ifdef CONFIG_BT_HCIUART_BCM
467 	case 15:
468 		hdev->set_bdaddr = btbcm_set_bdaddr;
469 		btbcm_check_bdaddr(hdev);
470 		break;
471 #endif
472 	default:
473 		break;
474 	}
475 
476 done:
477 	kfree_skb(skb);
478 	return 0;
479 }
480 
481 /* ------ LDISC part ------ */
482 /* hci_uart_tty_open
483  *
484  *     Called when line discipline changed to HCI_UART.
485  *
486  * Arguments:
487  *     tty    pointer to tty info structure
488  * Return Value:
489  *     0 if success, otherwise error code
490  */
491 static int hci_uart_tty_open(struct tty_struct *tty)
492 {
493 	struct hci_uart *hu;
494 
495 	BT_DBG("tty %p", tty);
496 
497 	if (!capable(CAP_NET_ADMIN))
498 		return -EPERM;
499 
500 	/* Error if the tty has no write op instead of leaving an exploitable
501 	 * hole
502 	 */
503 	if (tty->ops->write == NULL)
504 		return -EOPNOTSUPP;
505 
506 	hu = kzalloc_obj(*hu);
507 	if (!hu) {
508 		BT_ERR("Can't allocate control structure");
509 		return -ENFILE;
510 	}
511 	if (percpu_init_rwsem(&hu->proto_lock)) {
512 		BT_ERR("Can't allocate semaphore structure");
513 		kfree(hu);
514 		return -ENOMEM;
515 	}
516 
517 	tty->disc_data = hu;
518 	hu->tty = tty;
519 	tty->receive_room = 65536;
520 
521 	/* disable alignment support by default */
522 	hu->alignment = 1;
523 	hu->padding = 0;
524 
525 	/* Use serial port speed as oper_speed */
526 	hu->oper_speed = tty->termios.c_ospeed;
527 
528 	INIT_WORK(&hu->init_ready, hci_uart_init_work);
529 	INIT_WORK(&hu->write_work, hci_uart_write_work);
530 
531 	/* Flush any pending characters in the driver */
532 	tty_driver_flush_buffer(tty);
533 
534 	return 0;
535 }
536 
537 /* hci_uart_tty_close()
538  *
539  *    Called when the line discipline is changed to something
540  *    else, the tty is closed, or the tty detects a hangup.
541  */
542 static void hci_uart_tty_close(struct tty_struct *tty)
543 {
544 	struct hci_uart *hu = tty->disc_data;
545 	struct hci_dev *hdev;
546 	bool proto_ready;
547 
548 	BT_DBG("tty %p", tty);
549 
550 	/* Detach from the tty */
551 	tty->disc_data = NULL;
552 
553 	if (!hu)
554 		return;
555 
556 	/* Wait for init_ready to finish to prevent registration races */
557 	cancel_work_sync(&hu->init_ready);
558 
559 	proto_ready = test_bit(HCI_UART_PROTO_READY, &hu->flags);
560 	if (proto_ready) {
561 		percpu_down_write(&hu->proto_lock);
562 		clear_bit(HCI_UART_PROTO_READY, &hu->flags);
563 		percpu_up_write(&hu->proto_lock);
564 	}
565 
566 	/*
567 	 * Unconditionally cancel write_work AFTER clearing PROTO_READY.
568 	 * This ensures that concurrent protocol timers cannot requeue
569 	 * write_work via hci_uart_tx_wakeup(), permanently preventing
570 	 * double-free races and UAFs.
571 	 */
572 	cancel_work_sync(&hu->write_work);
573 
574 	hdev = hu->hdev;
575 	if (hdev)
576 		hci_uart_close(hdev); /* proto->flush is safely skipped */
577 
578 	if (proto_ready) {
579 		if (hdev) {
580 			if (test_bit(HCI_UART_REGISTERED, &hu->flags))
581 				hci_unregister_dev(hdev);
582 		}
583 		/* Close protocol before freeing hdev (intrinsically purges queues) */
584 		hu->proto->close(hu);
585 
586 		if (hdev)
587 			hci_free_dev(hdev);
588 	}
589 	clear_bit(HCI_UART_PROTO_SET, &hu->flags);
590 
591 	percpu_free_rwsem(&hu->proto_lock);
592 
593 	kfree(hu);
594 }
595 
596 /* hci_uart_tty_wakeup()
597  *
598  *    Callback for transmit wakeup. Called when low level
599  *    device driver can accept more send data.
600  *
601  * Arguments:        tty    pointer to associated tty instance data
602  * Return Value:    None
603  */
604 static void hci_uart_tty_wakeup(struct tty_struct *tty)
605 {
606 	struct hci_uart *hu = tty->disc_data;
607 
608 	BT_DBG("");
609 
610 	if (!hu)
611 		return;
612 
613 	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
614 
615 	if (tty != hu->tty)
616 		return;
617 
618 	if (test_bit(HCI_UART_PROTO_READY, &hu->flags) ||
619 	    test_bit(HCI_UART_PROTO_INIT, &hu->flags))
620 		hci_uart_tx_wakeup(hu);
621 }
622 
623 /* hci_uart_tty_receive()
624  *
625  *     Called by tty low level driver when receive data is
626  *     available.
627  *
628  * Arguments:  tty          pointer to tty instance data
629  *             data         pointer to received data
630  *             flags        pointer to flags for data
631  *             count        count of received data in bytes
632  *
633  * Return Value:    None
634  */
635 static void hci_uart_tty_receive(struct tty_struct *tty, const u8 *data,
636 				 const u8 *flags, size_t count)
637 {
638 	struct hci_uart *hu = tty->disc_data;
639 
640 	if (!hu || tty != hu->tty)
641 		return;
642 
643 	percpu_down_read(&hu->proto_lock);
644 
645 	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags) &&
646 	    !test_bit(HCI_UART_PROTO_INIT, &hu->flags)) {
647 		percpu_up_read(&hu->proto_lock);
648 		return;
649 	}
650 
651 	/* It does not need a lock here as it is already protected by a mutex in
652 	 * tty caller
653 	 */
654 	hu->proto->recv(hu, data, count);
655 
656 	if (hu->hdev)
657 		hu->hdev->stat.byte_rx += count;
658 
659 	percpu_up_read(&hu->proto_lock);
660 
661 	tty_unthrottle(tty);
662 }
663 
664 static int hci_uart_register_dev(struct hci_uart *hu)
665 {
666 	struct hci_dev *hdev;
667 	int err;
668 
669 	BT_DBG("");
670 
671 	/* Initialize and register HCI device */
672 	hdev = hci_alloc_dev();
673 	if (!hdev) {
674 		BT_ERR("Can't allocate HCI device");
675 		return -ENOMEM;
676 	}
677 
678 	hu->hdev = hdev;
679 
680 	hdev->bus = HCI_UART;
681 	hci_set_drvdata(hdev, hu);
682 
683 	/* Only when vendor specific setup callback is provided, consider
684 	 * the manufacturer information valid. This avoids filling in the
685 	 * value for Ericsson when nothing is specified.
686 	 */
687 	if (hu->proto->setup)
688 		hdev->manufacturer = hu->proto->manufacturer;
689 
690 	hdev->open  = hci_uart_open;
691 	hdev->close = hci_uart_close;
692 	hdev->flush = hci_uart_flush;
693 	hdev->send  = hci_uart_send_frame;
694 	hdev->setup = hci_uart_setup;
695 	SET_HCIDEV_DEV(hdev, hu->tty->dev);
696 
697 	if (test_bit(HCI_UART_RAW_DEVICE, &hu->hdev_flags))
698 		hci_set_quirk(hdev, HCI_QUIRK_RAW_DEVICE);
699 
700 	if (test_bit(HCI_UART_EXT_CONFIG, &hu->hdev_flags))
701 		hci_set_quirk(hdev, HCI_QUIRK_EXTERNAL_CONFIG);
702 
703 	if (!test_bit(HCI_UART_RESET_ON_INIT, &hu->hdev_flags))
704 		hci_set_quirk(hdev, HCI_QUIRK_RESET_ON_CLOSE);
705 
706 	/* Only call open() for the protocol after hdev is fully initialized as
707 	 * open() (or a timer/workqueue it starts) may attempt to reference it.
708 	 */
709 	err = hu->proto->open(hu);
710 	if (err) {
711 		hu->hdev = NULL;
712 		hci_free_dev(hdev);
713 		return err;
714 	}
715 
716 	set_bit(HCI_UART_PROTO_INIT, &hu->flags);
717 
718 	if (test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
719 		return 0;
720 
721 	if (hci_register_dev(hdev) < 0) {
722 		BT_ERR("Can't register HCI device");
723 		percpu_down_write(&hu->proto_lock);
724 		clear_bit(HCI_UART_PROTO_INIT, &hu->flags);
725 		percpu_up_write(&hu->proto_lock);
726 		/* Cancel work after clearing flags */
727 		cancel_work_sync(&hu->write_work);
728 
729 		/* Close protocol before freeing hdev */
730 		hu->proto->close(hu);
731 		hu->hdev = NULL;
732 		hci_free_dev(hdev);
733 		return -ENODEV;
734 	}
735 
736 	set_bit(HCI_UART_REGISTERED, &hu->flags);
737 
738 	return 0;
739 }
740 
741 static int hci_uart_set_proto(struct hci_uart *hu, int id)
742 {
743 	const struct hci_uart_proto *p;
744 	int err;
745 
746 	p = hci_uart_get_proto(id);
747 	if (!p)
748 		return -EPROTONOSUPPORT;
749 
750 	hu->proto = p;
751 
752 	err = hci_uart_register_dev(hu);
753 	if (err) {
754 		return err;
755 	}
756 
757 	set_bit(HCI_UART_PROTO_READY, &hu->flags);
758 	clear_bit(HCI_UART_PROTO_INIT, &hu->flags);
759 
760 	return 0;
761 }
762 
763 static int hci_uart_set_flags(struct hci_uart *hu, unsigned long flags)
764 {
765 	unsigned long valid_flags = BIT(HCI_UART_RAW_DEVICE) |
766 				    BIT(HCI_UART_RESET_ON_INIT) |
767 				    BIT(HCI_UART_INIT_PENDING) |
768 				    BIT(HCI_UART_EXT_CONFIG) |
769 				    BIT(HCI_UART_VND_DETECT);
770 
771 	if (flags & ~valid_flags)
772 		return -EINVAL;
773 
774 	hu->hdev_flags = flags;
775 
776 	return 0;
777 }
778 
779 /* hci_uart_tty_ioctl()
780  *
781  *    Process IOCTL system call for the tty device.
782  *
783  * Arguments:
784  *
785  *    tty        pointer to tty instance data
786  *    cmd        IOCTL command code
787  *    arg        argument for IOCTL call (cmd dependent)
788  *
789  * Return Value:    Command dependent
790  */
791 static int hci_uart_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
792 			      unsigned long arg)
793 {
794 	struct hci_uart *hu = tty->disc_data;
795 	int err = 0;
796 
797 	BT_DBG("");
798 
799 	/* Verify the status of the device */
800 	if (!hu)
801 		return -EBADF;
802 
803 	switch (cmd) {
804 	case HCIUARTSETPROTO:
805 		if (!test_and_set_bit(HCI_UART_PROTO_SET, &hu->flags)) {
806 			err = hci_uart_set_proto(hu, arg);
807 			if (err)
808 				clear_bit(HCI_UART_PROTO_SET, &hu->flags);
809 		} else
810 			err = -EBUSY;
811 		break;
812 
813 	case HCIUARTGETPROTO:
814 		if (test_bit(HCI_UART_PROTO_SET, &hu->flags) &&
815 		    test_bit(HCI_UART_PROTO_READY, &hu->flags))
816 			err = hu->proto->id;
817 		else
818 			err = -EUNATCH;
819 		break;
820 
821 	case HCIUARTGETDEVICE:
822 		if (test_bit(HCI_UART_REGISTERED, &hu->flags))
823 			err = hu->hdev->id;
824 		else
825 			err = -EUNATCH;
826 		break;
827 
828 	case HCIUARTSETFLAGS:
829 		if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
830 			err = -EBUSY;
831 		else
832 			err = hci_uart_set_flags(hu, arg);
833 		break;
834 
835 	case HCIUARTGETFLAGS:
836 		err = hu->hdev_flags;
837 		break;
838 
839 	default:
840 		err = n_tty_ioctl_helper(tty, cmd, arg);
841 		break;
842 	}
843 
844 	return err;
845 }
846 
847 /*
848  * We don't provide read/write/poll interface for user space.
849  */
850 static ssize_t hci_uart_tty_read(struct tty_struct *tty, struct file *file,
851 				 u8 *buf, size_t nr, void **cookie,
852 				 unsigned long offset)
853 {
854 	return 0;
855 }
856 
857 static ssize_t hci_uart_tty_write(struct tty_struct *tty, struct file *file,
858 				  const u8 *data, size_t count)
859 {
860 	return 0;
861 }
862 
863 static struct tty_ldisc_ops hci_uart_ldisc = {
864 	.owner		= THIS_MODULE,
865 	.num		= N_HCI,
866 	.name		= "n_hci",
867 	.open		= hci_uart_tty_open,
868 	.close		= hci_uart_tty_close,
869 	.read		= hci_uart_tty_read,
870 	.write		= hci_uart_tty_write,
871 	.ioctl		= hci_uart_tty_ioctl,
872 	.compat_ioctl	= hci_uart_tty_ioctl,
873 	.receive_buf	= hci_uart_tty_receive,
874 	.write_wakeup	= hci_uart_tty_wakeup,
875 };
876 
877 static int __init hci_uart_init(void)
878 {
879 	int err;
880 
881 	BT_INFO("HCI UART driver ver %s", VERSION);
882 
883 	/* Register the tty discipline */
884 	err = tty_register_ldisc(&hci_uart_ldisc);
885 	if (err) {
886 		BT_ERR("HCI line discipline registration failed. (%d)", err);
887 		return err;
888 	}
889 
890 #ifdef CONFIG_BT_HCIUART_H4
891 	h4_init();
892 #endif
893 #ifdef CONFIG_BT_HCIUART_BCSP
894 	bcsp_init();
895 #endif
896 #ifdef CONFIG_BT_HCIUART_LL
897 	ll_init();
898 #endif
899 #ifdef CONFIG_BT_HCIUART_ATH3K
900 	ath_init();
901 #endif
902 #ifdef CONFIG_BT_HCIUART_3WIRE
903 	h5_init();
904 #endif
905 #ifdef CONFIG_BT_HCIUART_INTEL
906 	intel_init();
907 #endif
908 #ifdef CONFIG_BT_HCIUART_BCM
909 	bcm_init();
910 #endif
911 #ifdef CONFIG_BT_HCIUART_QCA
912 	qca_init();
913 #endif
914 #ifdef CONFIG_BT_HCIUART_AG6XX
915 	ag6xx_init();
916 #endif
917 #ifdef CONFIG_BT_HCIUART_MRVL
918 	mrvl_init();
919 #endif
920 #ifdef CONFIG_BT_HCIUART_AML
921 	aml_init();
922 #endif
923 	return 0;
924 }
925 
926 static void __exit hci_uart_exit(void)
927 {
928 #ifdef CONFIG_BT_HCIUART_H4
929 	h4_deinit();
930 #endif
931 #ifdef CONFIG_BT_HCIUART_BCSP
932 	bcsp_deinit();
933 #endif
934 #ifdef CONFIG_BT_HCIUART_LL
935 	ll_deinit();
936 #endif
937 #ifdef CONFIG_BT_HCIUART_ATH3K
938 	ath_deinit();
939 #endif
940 #ifdef CONFIG_BT_HCIUART_3WIRE
941 	h5_deinit();
942 #endif
943 #ifdef CONFIG_BT_HCIUART_INTEL
944 	intel_deinit();
945 #endif
946 #ifdef CONFIG_BT_HCIUART_BCM
947 	bcm_deinit();
948 #endif
949 #ifdef CONFIG_BT_HCIUART_QCA
950 	qca_deinit();
951 #endif
952 #ifdef CONFIG_BT_HCIUART_AG6XX
953 	ag6xx_deinit();
954 #endif
955 #ifdef CONFIG_BT_HCIUART_MRVL
956 	mrvl_deinit();
957 #endif
958 #ifdef CONFIG_BT_HCIUART_AML
959 	aml_deinit();
960 #endif
961 	tty_unregister_ldisc(&hci_uart_ldisc);
962 }
963 
964 module_init(hci_uart_init);
965 module_exit(hci_uart_exit);
966 
967 MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
968 MODULE_DESCRIPTION("Bluetooth HCI UART driver ver " VERSION);
969 MODULE_VERSION(VERSION);
970 MODULE_LICENSE("GPL");
971 MODULE_ALIAS_LDISC(N_HCI);
972