xref: /openbmc/linux/drivers/bluetooth/hci_ldisc.c (revision 7f6964c5)
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 			skb = hu->proto->dequeue(hu);
107 
108 		percpu_up_read(&hu->proto_lock);
109 	} else {
110 		hu->tx_skb = NULL;
111 	}
112 
113 	return skb;
114 }
115 
116 int hci_uart_tx_wakeup(struct hci_uart *hu)
117 {
118 	/* This may be called in an IRQ context, so we can't sleep. Therefore
119 	 * we try to acquire the lock only, and if that fails we assume the
120 	 * tty is being closed because that is the only time the write lock is
121 	 * acquired. If, however, at some point in the future the write lock
122 	 * is also acquired in other situations, then this must be revisited.
123 	 */
124 	if (!percpu_down_read_trylock(&hu->proto_lock))
125 		return 0;
126 
127 	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags))
128 		goto no_schedule;
129 
130 	if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) {
131 		set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
132 		goto no_schedule;
133 	}
134 
135 	BT_DBG("");
136 
137 	schedule_work(&hu->write_work);
138 
139 no_schedule:
140 	percpu_up_read(&hu->proto_lock);
141 
142 	return 0;
143 }
144 EXPORT_SYMBOL_GPL(hci_uart_tx_wakeup);
145 
146 static void hci_uart_write_work(struct work_struct *work)
147 {
148 	struct hci_uart *hu = container_of(work, struct hci_uart, write_work);
149 	struct tty_struct *tty = hu->tty;
150 	struct hci_dev *hdev = hu->hdev;
151 	struct sk_buff *skb;
152 
153 	/* REVISIT: should we cope with bad skbs or ->write() returning
154 	 * and error value ?
155 	 */
156 
157 restart:
158 	clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
159 
160 	while ((skb = hci_uart_dequeue(hu))) {
161 		int len;
162 
163 		set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
164 		len = tty->ops->write(tty, skb->data, skb->len);
165 		hdev->stat.byte_tx += len;
166 
167 		skb_pull(skb, len);
168 		if (skb->len) {
169 			hu->tx_skb = skb;
170 			break;
171 		}
172 
173 		hci_uart_tx_complete(hu, hci_skb_pkt_type(skb));
174 		kfree_skb(skb);
175 	}
176 
177 	if (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state))
178 		goto restart;
179 
180 	clear_bit(HCI_UART_SENDING, &hu->tx_state);
181 }
182 
183 void hci_uart_init_work(struct work_struct *work)
184 {
185 	struct hci_uart *hu = container_of(work, struct hci_uart, init_ready);
186 	int err;
187 	struct hci_dev *hdev;
188 
189 	if (!test_and_clear_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
190 		return;
191 
192 	err = hci_register_dev(hu->hdev);
193 	if (err < 0) {
194 		BT_ERR("Can't register HCI device");
195 		clear_bit(HCI_UART_PROTO_READY, &hu->flags);
196 		hu->proto->close(hu);
197 		hdev = hu->hdev;
198 		hu->hdev = NULL;
199 		hci_free_dev(hdev);
200 		return;
201 	}
202 
203 	set_bit(HCI_UART_REGISTERED, &hu->flags);
204 }
205 
206 int hci_uart_init_ready(struct hci_uart *hu)
207 {
208 	if (!test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
209 		return -EALREADY;
210 
211 	schedule_work(&hu->init_ready);
212 
213 	return 0;
214 }
215 
216 /* ------- Interface to HCI layer ------ */
217 /* Reset device */
218 static int hci_uart_flush(struct hci_dev *hdev)
219 {
220 	struct hci_uart *hu  = hci_get_drvdata(hdev);
221 	struct tty_struct *tty = hu->tty;
222 
223 	BT_DBG("hdev %p tty %p", hdev, tty);
224 
225 	if (hu->tx_skb) {
226 		kfree_skb(hu->tx_skb); hu->tx_skb = NULL;
227 	}
228 
229 	/* Flush any pending characters in the driver and discipline. */
230 	tty_ldisc_flush(tty);
231 	tty_driver_flush_buffer(tty);
232 
233 	percpu_down_read(&hu->proto_lock);
234 
235 	if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
236 		hu->proto->flush(hu);
237 
238 	percpu_up_read(&hu->proto_lock);
239 
240 	return 0;
241 }
242 
243 /* Initialize device */
244 static int hci_uart_open(struct hci_dev *hdev)
245 {
246 	BT_DBG("%s %p", hdev->name, hdev);
247 
248 	/* Undo clearing this from hci_uart_close() */
249 	hdev->flush = hci_uart_flush;
250 
251 	return 0;
252 }
253 
254 /* Close device */
255 static int hci_uart_close(struct hci_dev *hdev)
256 {
257 	BT_DBG("hdev %p", hdev);
258 
259 	hci_uart_flush(hdev);
260 	hdev->flush = NULL;
261 	return 0;
262 }
263 
264 /* Send frames from HCI layer */
265 static int hci_uart_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
266 {
267 	struct hci_uart *hu = hci_get_drvdata(hdev);
268 
269 	BT_DBG("%s: type %d len %d", hdev->name, hci_skb_pkt_type(skb),
270 	       skb->len);
271 
272 	percpu_down_read(&hu->proto_lock);
273 
274 	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
275 		percpu_up_read(&hu->proto_lock);
276 		return -EUNATCH;
277 	}
278 
279 	hu->proto->enqueue(hu, skb);
280 	percpu_up_read(&hu->proto_lock);
281 
282 	hci_uart_tx_wakeup(hu);
283 
284 	return 0;
285 }
286 
287 /* Flow control or un-flow control the device */
288 void hci_uart_set_flow_control(struct hci_uart *hu, bool enable)
289 {
290 	struct tty_struct *tty = hu->tty;
291 	struct ktermios ktermios;
292 	int status;
293 	unsigned int set = 0;
294 	unsigned int clear = 0;
295 
296 	if (hu->serdev) {
297 		serdev_device_set_flow_control(hu->serdev, !enable);
298 		serdev_device_set_rts(hu->serdev, !enable);
299 		return;
300 	}
301 
302 	if (enable) {
303 		/* Disable hardware flow control */
304 		ktermios = tty->termios;
305 		ktermios.c_cflag &= ~CRTSCTS;
306 		status = tty_set_termios(tty, &ktermios);
307 		BT_DBG("Disabling hardware flow control: %s",
308 		       status ? "failed" : "success");
309 
310 		/* Clear RTS to prevent the device from sending */
311 		/* Most UARTs need OUT2 to enable interrupts */
312 		status = tty->driver->ops->tiocmget(tty);
313 		BT_DBG("Current tiocm 0x%x", status);
314 
315 		set &= ~(TIOCM_OUT2 | TIOCM_RTS);
316 		clear = ~set;
317 		set &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
318 		       TIOCM_OUT2 | TIOCM_LOOP;
319 		clear &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
320 			 TIOCM_OUT2 | TIOCM_LOOP;
321 		status = tty->driver->ops->tiocmset(tty, set, clear);
322 		BT_DBG("Clearing RTS: %s", status ? "failed" : "success");
323 	} else {
324 		/* Set RTS to allow the device to send again */
325 		status = tty->driver->ops->tiocmget(tty);
326 		BT_DBG("Current tiocm 0x%x", status);
327 
328 		set |= (TIOCM_OUT2 | TIOCM_RTS);
329 		clear = ~set;
330 		set &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
331 		       TIOCM_OUT2 | TIOCM_LOOP;
332 		clear &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
333 			 TIOCM_OUT2 | TIOCM_LOOP;
334 		status = tty->driver->ops->tiocmset(tty, set, clear);
335 		BT_DBG("Setting RTS: %s", status ? "failed" : "success");
336 
337 		/* Re-enable hardware flow control */
338 		ktermios = tty->termios;
339 		ktermios.c_cflag |= CRTSCTS;
340 		status = tty_set_termios(tty, &ktermios);
341 		BT_DBG("Enabling hardware flow control: %s",
342 		       status ? "failed" : "success");
343 	}
344 }
345 
346 void hci_uart_set_speeds(struct hci_uart *hu, unsigned int init_speed,
347 			 unsigned int oper_speed)
348 {
349 	hu->init_speed = init_speed;
350 	hu->oper_speed = oper_speed;
351 }
352 
353 void hci_uart_set_baudrate(struct hci_uart *hu, unsigned int speed)
354 {
355 	struct tty_struct *tty = hu->tty;
356 	struct ktermios ktermios;
357 
358 	ktermios = tty->termios;
359 	ktermios.c_cflag &= ~CBAUD;
360 	tty_termios_encode_baud_rate(&ktermios, speed, speed);
361 
362 	/* tty_set_termios() return not checked as it is always 0 */
363 	tty_set_termios(tty, &ktermios);
364 
365 	BT_DBG("%s: New tty speeds: %d/%d", hu->hdev->name,
366 	       tty->termios.c_ispeed, tty->termios.c_ospeed);
367 }
368 
369 static int hci_uart_setup(struct hci_dev *hdev)
370 {
371 	struct hci_uart *hu = hci_get_drvdata(hdev);
372 	struct hci_rp_read_local_version *ver;
373 	struct sk_buff *skb;
374 	unsigned int speed;
375 	int err;
376 
377 	/* Init speed if any */
378 	if (hu->init_speed)
379 		speed = hu->init_speed;
380 	else if (hu->proto->init_speed)
381 		speed = hu->proto->init_speed;
382 	else
383 		speed = 0;
384 
385 	if (speed)
386 		hci_uart_set_baudrate(hu, speed);
387 
388 	/* Operational speed if any */
389 	if (hu->oper_speed)
390 		speed = hu->oper_speed;
391 	else if (hu->proto->oper_speed)
392 		speed = hu->proto->oper_speed;
393 	else
394 		speed = 0;
395 
396 	if (hu->proto->set_baudrate && speed) {
397 		err = hu->proto->set_baudrate(hu, speed);
398 		if (!err)
399 			hci_uart_set_baudrate(hu, speed);
400 	}
401 
402 	if (hu->proto->setup)
403 		return hu->proto->setup(hu);
404 
405 	if (!test_bit(HCI_UART_VND_DETECT, &hu->hdev_flags))
406 		return 0;
407 
408 	skb = __hci_cmd_sync(hdev, HCI_OP_READ_LOCAL_VERSION, 0, NULL,
409 			     HCI_INIT_TIMEOUT);
410 	if (IS_ERR(skb)) {
411 		BT_ERR("%s: Reading local version information failed (%ld)",
412 		       hdev->name, PTR_ERR(skb));
413 		return 0;
414 	}
415 
416 	if (skb->len != sizeof(*ver)) {
417 		BT_ERR("%s: Event length mismatch for version information",
418 		       hdev->name);
419 		goto done;
420 	}
421 
422 	ver = (struct hci_rp_read_local_version *)skb->data;
423 
424 	switch (le16_to_cpu(ver->manufacturer)) {
425 #ifdef CONFIG_BT_HCIUART_INTEL
426 	case 2:
427 		hdev->set_bdaddr = btintel_set_bdaddr;
428 		btintel_check_bdaddr(hdev);
429 		break;
430 #endif
431 #ifdef CONFIG_BT_HCIUART_BCM
432 	case 15:
433 		hdev->set_bdaddr = btbcm_set_bdaddr;
434 		btbcm_check_bdaddr(hdev);
435 		break;
436 #endif
437 	default:
438 		break;
439 	}
440 
441 done:
442 	kfree_skb(skb);
443 	return 0;
444 }
445 
446 /* ------ LDISC part ------ */
447 /* hci_uart_tty_open
448  *
449  *     Called when line discipline changed to HCI_UART.
450  *
451  * Arguments:
452  *     tty    pointer to tty info structure
453  * Return Value:
454  *     0 if success, otherwise error code
455  */
456 static int hci_uart_tty_open(struct tty_struct *tty)
457 {
458 	struct hci_uart *hu;
459 
460 	BT_DBG("tty %p", tty);
461 
462 	/* Error if the tty has no write op instead of leaving an exploitable
463 	 * hole
464 	 */
465 	if (tty->ops->write == NULL)
466 		return -EOPNOTSUPP;
467 
468 	hu = kzalloc(sizeof(struct hci_uart), GFP_KERNEL);
469 	if (!hu) {
470 		BT_ERR("Can't allocate control structure");
471 		return -ENFILE;
472 	}
473 
474 	tty->disc_data = hu;
475 	hu->tty = tty;
476 	tty->receive_room = 65536;
477 
478 	/* disable alignment support by default */
479 	hu->alignment = 1;
480 	hu->padding = 0;
481 
482 	INIT_WORK(&hu->init_ready, hci_uart_init_work);
483 	INIT_WORK(&hu->write_work, hci_uart_write_work);
484 
485 	percpu_init_rwsem(&hu->proto_lock);
486 
487 	/* Flush any pending characters in the driver */
488 	tty_driver_flush_buffer(tty);
489 
490 	return 0;
491 }
492 
493 /* hci_uart_tty_close()
494  *
495  *    Called when the line discipline is changed to something
496  *    else, the tty is closed, or the tty detects a hangup.
497  */
498 static void hci_uart_tty_close(struct tty_struct *tty)
499 {
500 	struct hci_uart *hu = tty->disc_data;
501 	struct hci_dev *hdev;
502 
503 	BT_DBG("tty %p", tty);
504 
505 	/* Detach from the tty */
506 	tty->disc_data = NULL;
507 
508 	if (!hu)
509 		return;
510 
511 	hdev = hu->hdev;
512 	if (hdev)
513 		hci_uart_close(hdev);
514 
515 	if (test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
516 		percpu_down_write(&hu->proto_lock);
517 		clear_bit(HCI_UART_PROTO_READY, &hu->flags);
518 		percpu_up_write(&hu->proto_lock);
519 
520 		cancel_work_sync(&hu->write_work);
521 
522 		if (hdev) {
523 			if (test_bit(HCI_UART_REGISTERED, &hu->flags))
524 				hci_unregister_dev(hdev);
525 			hci_free_dev(hdev);
526 		}
527 		hu->proto->close(hu);
528 	}
529 	clear_bit(HCI_UART_PROTO_SET, &hu->flags);
530 
531 	percpu_free_rwsem(&hu->proto_lock);
532 
533 	kfree(hu);
534 }
535 
536 /* hci_uart_tty_wakeup()
537  *
538  *    Callback for transmit wakeup. Called when low level
539  *    device driver can accept more send data.
540  *
541  * Arguments:        tty    pointer to associated tty instance data
542  * Return Value:    None
543  */
544 static void hci_uart_tty_wakeup(struct tty_struct *tty)
545 {
546 	struct hci_uart *hu = tty->disc_data;
547 
548 	BT_DBG("");
549 
550 	if (!hu)
551 		return;
552 
553 	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
554 
555 	if (tty != hu->tty)
556 		return;
557 
558 	if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
559 		hci_uart_tx_wakeup(hu);
560 }
561 
562 /* hci_uart_tty_receive()
563  *
564  *     Called by tty low level driver when receive data is
565  *     available.
566  *
567  * Arguments:  tty          pointer to tty isntance data
568  *             data         pointer to received data
569  *             flags        pointer to flags for data
570  *             count        count of received data in bytes
571  *
572  * Return Value:    None
573  */
574 static void hci_uart_tty_receive(struct tty_struct *tty, const u8 *data,
575 				 char *flags, int count)
576 {
577 	struct hci_uart *hu = tty->disc_data;
578 
579 	if (!hu || tty != hu->tty)
580 		return;
581 
582 	percpu_down_read(&hu->proto_lock);
583 
584 	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
585 		percpu_up_read(&hu->proto_lock);
586 		return;
587 	}
588 
589 	/* It does not need a lock here as it is already protected by a mutex in
590 	 * tty caller
591 	 */
592 	hu->proto->recv(hu, data, count);
593 	percpu_up_read(&hu->proto_lock);
594 
595 	if (hu->hdev)
596 		hu->hdev->stat.byte_rx += count;
597 
598 	tty_unthrottle(tty);
599 }
600 
601 static int hci_uart_register_dev(struct hci_uart *hu)
602 {
603 	struct hci_dev *hdev;
604 	int err;
605 
606 	BT_DBG("");
607 
608 	/* Initialize and register HCI device */
609 	hdev = hci_alloc_dev();
610 	if (!hdev) {
611 		BT_ERR("Can't allocate HCI device");
612 		return -ENOMEM;
613 	}
614 
615 	hu->hdev = hdev;
616 
617 	hdev->bus = HCI_UART;
618 	hci_set_drvdata(hdev, hu);
619 
620 	/* Only when vendor specific setup callback is provided, consider
621 	 * the manufacturer information valid. This avoids filling in the
622 	 * value for Ericsson when nothing is specified.
623 	 */
624 	if (hu->proto->setup)
625 		hdev->manufacturer = hu->proto->manufacturer;
626 
627 	hdev->open  = hci_uart_open;
628 	hdev->close = hci_uart_close;
629 	hdev->flush = hci_uart_flush;
630 	hdev->send  = hci_uart_send_frame;
631 	hdev->setup = hci_uart_setup;
632 	SET_HCIDEV_DEV(hdev, hu->tty->dev);
633 
634 	if (test_bit(HCI_UART_RAW_DEVICE, &hu->hdev_flags))
635 		set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
636 
637 	if (test_bit(HCI_UART_EXT_CONFIG, &hu->hdev_flags))
638 		set_bit(HCI_QUIRK_EXTERNAL_CONFIG, &hdev->quirks);
639 
640 	if (!test_bit(HCI_UART_RESET_ON_INIT, &hu->hdev_flags))
641 		set_bit(HCI_QUIRK_RESET_ON_CLOSE, &hdev->quirks);
642 
643 	if (test_bit(HCI_UART_CREATE_AMP, &hu->hdev_flags))
644 		hdev->dev_type = HCI_AMP;
645 	else
646 		hdev->dev_type = HCI_PRIMARY;
647 
648 	/* Only call open() for the protocol after hdev is fully initialized as
649 	 * open() (or a timer/workqueue it starts) may attempt to reference it.
650 	 */
651 	err = hu->proto->open(hu);
652 	if (err) {
653 		hu->hdev = NULL;
654 		hci_free_dev(hdev);
655 		return err;
656 	}
657 
658 	if (test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
659 		return 0;
660 
661 	if (hci_register_dev(hdev) < 0) {
662 		BT_ERR("Can't register HCI device");
663 		hu->proto->close(hu);
664 		hu->hdev = NULL;
665 		hci_free_dev(hdev);
666 		return -ENODEV;
667 	}
668 
669 	set_bit(HCI_UART_REGISTERED, &hu->flags);
670 
671 	return 0;
672 }
673 
674 static int hci_uart_set_proto(struct hci_uart *hu, int id)
675 {
676 	const struct hci_uart_proto *p;
677 	int err;
678 
679 	p = hci_uart_get_proto(id);
680 	if (!p)
681 		return -EPROTONOSUPPORT;
682 
683 	hu->proto = p;
684 
685 	err = hci_uart_register_dev(hu);
686 	if (err) {
687 		return err;
688 	}
689 
690 	set_bit(HCI_UART_PROTO_READY, &hu->flags);
691 	return 0;
692 }
693 
694 static int hci_uart_set_flags(struct hci_uart *hu, unsigned long flags)
695 {
696 	unsigned long valid_flags = BIT(HCI_UART_RAW_DEVICE) |
697 				    BIT(HCI_UART_RESET_ON_INIT) |
698 				    BIT(HCI_UART_CREATE_AMP) |
699 				    BIT(HCI_UART_INIT_PENDING) |
700 				    BIT(HCI_UART_EXT_CONFIG) |
701 				    BIT(HCI_UART_VND_DETECT);
702 
703 	if (flags & ~valid_flags)
704 		return -EINVAL;
705 
706 	hu->hdev_flags = flags;
707 
708 	return 0;
709 }
710 
711 /* hci_uart_tty_ioctl()
712  *
713  *    Process IOCTL system call for the tty device.
714  *
715  * Arguments:
716  *
717  *    tty        pointer to tty instance data
718  *    file       pointer to open file object for device
719  *    cmd        IOCTL command code
720  *    arg        argument for IOCTL call (cmd dependent)
721  *
722  * Return Value:    Command dependent
723  */
724 static int hci_uart_tty_ioctl(struct tty_struct *tty, struct file *file,
725 			      unsigned int cmd, unsigned long arg)
726 {
727 	struct hci_uart *hu = tty->disc_data;
728 	int err = 0;
729 
730 	BT_DBG("");
731 
732 	/* Verify the status of the device */
733 	if (!hu)
734 		return -EBADF;
735 
736 	switch (cmd) {
737 	case HCIUARTSETPROTO:
738 		if (!test_and_set_bit(HCI_UART_PROTO_SET, &hu->flags)) {
739 			err = hci_uart_set_proto(hu, arg);
740 			if (err)
741 				clear_bit(HCI_UART_PROTO_SET, &hu->flags);
742 		} else
743 			err = -EBUSY;
744 		break;
745 
746 	case HCIUARTGETPROTO:
747 		if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
748 			err = hu->proto->id;
749 		else
750 			err = -EUNATCH;
751 		break;
752 
753 	case HCIUARTGETDEVICE:
754 		if (test_bit(HCI_UART_REGISTERED, &hu->flags))
755 			err = hu->hdev->id;
756 		else
757 			err = -EUNATCH;
758 		break;
759 
760 	case HCIUARTSETFLAGS:
761 		if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
762 			err = -EBUSY;
763 		else
764 			err = hci_uart_set_flags(hu, arg);
765 		break;
766 
767 	case HCIUARTGETFLAGS:
768 		err = hu->hdev_flags;
769 		break;
770 
771 	default:
772 		err = n_tty_ioctl_helper(tty, file, cmd, arg);
773 		break;
774 	}
775 
776 	return err;
777 }
778 
779 /*
780  * We don't provide read/write/poll interface for user space.
781  */
782 static ssize_t hci_uart_tty_read(struct tty_struct *tty, struct file *file,
783 				 unsigned char __user *buf, size_t nr)
784 {
785 	return 0;
786 }
787 
788 static ssize_t hci_uart_tty_write(struct tty_struct *tty, struct file *file,
789 				  const unsigned char *data, size_t count)
790 {
791 	return 0;
792 }
793 
794 static __poll_t hci_uart_tty_poll(struct tty_struct *tty,
795 				      struct file *filp, poll_table *wait)
796 {
797 	return 0;
798 }
799 
800 static int __init hci_uart_init(void)
801 {
802 	static struct tty_ldisc_ops hci_uart_ldisc;
803 	int err;
804 
805 	BT_INFO("HCI UART driver ver %s", VERSION);
806 
807 	/* Register the tty discipline */
808 
809 	memset(&hci_uart_ldisc, 0, sizeof(hci_uart_ldisc));
810 	hci_uart_ldisc.magic		= TTY_LDISC_MAGIC;
811 	hci_uart_ldisc.name		= "n_hci";
812 	hci_uart_ldisc.open		= hci_uart_tty_open;
813 	hci_uart_ldisc.close		= hci_uart_tty_close;
814 	hci_uart_ldisc.read		= hci_uart_tty_read;
815 	hci_uart_ldisc.write		= hci_uart_tty_write;
816 	hci_uart_ldisc.ioctl		= hci_uart_tty_ioctl;
817 	hci_uart_ldisc.compat_ioctl	= hci_uart_tty_ioctl;
818 	hci_uart_ldisc.poll		= hci_uart_tty_poll;
819 	hci_uart_ldisc.receive_buf	= hci_uart_tty_receive;
820 	hci_uart_ldisc.write_wakeup	= hci_uart_tty_wakeup;
821 	hci_uart_ldisc.owner		= THIS_MODULE;
822 
823 	err = tty_register_ldisc(N_HCI, &hci_uart_ldisc);
824 	if (err) {
825 		BT_ERR("HCI line discipline registration failed. (%d)", err);
826 		return err;
827 	}
828 
829 #ifdef CONFIG_BT_HCIUART_H4
830 	h4_init();
831 #endif
832 #ifdef CONFIG_BT_HCIUART_BCSP
833 	bcsp_init();
834 #endif
835 #ifdef CONFIG_BT_HCIUART_LL
836 	ll_init();
837 #endif
838 #ifdef CONFIG_BT_HCIUART_ATH3K
839 	ath_init();
840 #endif
841 #ifdef CONFIG_BT_HCIUART_3WIRE
842 	h5_init();
843 #endif
844 #ifdef CONFIG_BT_HCIUART_INTEL
845 	intel_init();
846 #endif
847 #ifdef CONFIG_BT_HCIUART_BCM
848 	bcm_init();
849 #endif
850 #ifdef CONFIG_BT_HCIUART_QCA
851 	qca_init();
852 #endif
853 #ifdef CONFIG_BT_HCIUART_AG6XX
854 	ag6xx_init();
855 #endif
856 #ifdef CONFIG_BT_HCIUART_MRVL
857 	mrvl_init();
858 #endif
859 
860 	return 0;
861 }
862 
863 static void __exit hci_uart_exit(void)
864 {
865 	int err;
866 
867 #ifdef CONFIG_BT_HCIUART_H4
868 	h4_deinit();
869 #endif
870 #ifdef CONFIG_BT_HCIUART_BCSP
871 	bcsp_deinit();
872 #endif
873 #ifdef CONFIG_BT_HCIUART_LL
874 	ll_deinit();
875 #endif
876 #ifdef CONFIG_BT_HCIUART_ATH3K
877 	ath_deinit();
878 #endif
879 #ifdef CONFIG_BT_HCIUART_3WIRE
880 	h5_deinit();
881 #endif
882 #ifdef CONFIG_BT_HCIUART_INTEL
883 	intel_deinit();
884 #endif
885 #ifdef CONFIG_BT_HCIUART_BCM
886 	bcm_deinit();
887 #endif
888 #ifdef CONFIG_BT_HCIUART_QCA
889 	qca_deinit();
890 #endif
891 #ifdef CONFIG_BT_HCIUART_AG6XX
892 	ag6xx_deinit();
893 #endif
894 #ifdef CONFIG_BT_HCIUART_MRVL
895 	mrvl_deinit();
896 #endif
897 
898 	/* Release tty registration of line discipline */
899 	err = tty_unregister_ldisc(N_HCI);
900 	if (err)
901 		BT_ERR("Can't unregister HCI line discipline (%d)", err);
902 }
903 
904 module_init(hci_uart_init);
905 module_exit(hci_uart_exit);
906 
907 MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
908 MODULE_DESCRIPTION("Bluetooth HCI UART driver ver " VERSION);
909 MODULE_VERSION(VERSION);
910 MODULE_LICENSE("GPL");
911 MODULE_ALIAS_LDISC(N_HCI);
912