xref: /openbmc/linux/drivers/bluetooth/hci_ldisc.c (revision b6dcefde)
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 int reset = 0;
52 
53 static struct hci_uart_proto *hup[HCI_UART_MAX_PROTO];
54 
55 int hci_uart_register_proto(struct hci_uart_proto *p)
56 {
57 	if (p->id >= HCI_UART_MAX_PROTO)
58 		return -EINVAL;
59 
60 	if (hup[p->id])
61 		return -EEXIST;
62 
63 	hup[p->id] = p;
64 
65 	return 0;
66 }
67 
68 int hci_uart_unregister_proto(struct hci_uart_proto *p)
69 {
70 	if (p->id >= HCI_UART_MAX_PROTO)
71 		return -EINVAL;
72 
73 	if (!hup[p->id])
74 		return -EINVAL;
75 
76 	hup[p->id] = NULL;
77 
78 	return 0;
79 }
80 
81 static struct hci_uart_proto *hci_uart_get_proto(unsigned int id)
82 {
83 	if (id >= HCI_UART_MAX_PROTO)
84 		return NULL;
85 
86 	return hup[id];
87 }
88 
89 static inline void hci_uart_tx_complete(struct hci_uart *hu, int pkt_type)
90 {
91 	struct hci_dev *hdev = hu->hdev;
92 
93 	/* Update HCI stat counters */
94 	switch (pkt_type) {
95 	case HCI_COMMAND_PKT:
96 		hdev->stat.cmd_tx++;
97 		break;
98 
99 	case HCI_ACLDATA_PKT:
100 		hdev->stat.acl_tx++;
101 		break;
102 
103 	case HCI_SCODATA_PKT:
104 		hdev->stat.cmd_tx++;
105 		break;
106 	}
107 }
108 
109 static inline struct sk_buff *hci_uart_dequeue(struct hci_uart *hu)
110 {
111 	struct sk_buff *skb = hu->tx_skb;
112 
113 	if (!skb)
114 		skb = hu->proto->dequeue(hu);
115 	else
116 		hu->tx_skb = NULL;
117 
118 	return skb;
119 }
120 
121 int hci_uart_tx_wakeup(struct hci_uart *hu)
122 {
123 	struct tty_struct *tty = hu->tty;
124 	struct hci_dev *hdev = hu->hdev;
125 	struct sk_buff *skb;
126 
127 	if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) {
128 		set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
129 		return 0;
130 	}
131 
132 	BT_DBG("");
133 
134 restart:
135 	clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
136 
137 	while ((skb = hci_uart_dequeue(hu))) {
138 		int len;
139 
140 		set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
141 		len = tty->ops->write(tty, skb->data, skb->len);
142 		hdev->stat.byte_tx += len;
143 
144 		skb_pull(skb, len);
145 		if (skb->len) {
146 			hu->tx_skb = skb;
147 			break;
148 		}
149 
150 		hci_uart_tx_complete(hu, bt_cb(skb)->pkt_type);
151 		kfree_skb(skb);
152 	}
153 
154 	if (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state))
155 		goto restart;
156 
157 	clear_bit(HCI_UART_SENDING, &hu->tx_state);
158 	return 0;
159 }
160 
161 /* ------- Interface to HCI layer ------ */
162 /* Initialize device */
163 static int hci_uart_open(struct hci_dev *hdev)
164 {
165 	BT_DBG("%s %p", hdev->name, hdev);
166 
167 	/* Nothing to do for UART driver */
168 
169 	set_bit(HCI_RUNNING, &hdev->flags);
170 
171 	return 0;
172 }
173 
174 /* Reset device */
175 static int hci_uart_flush(struct hci_dev *hdev)
176 {
177 	struct hci_uart *hu  = (struct hci_uart *) hdev->driver_data;
178 	struct tty_struct *tty = hu->tty;
179 
180 	BT_DBG("hdev %p tty %p", hdev, tty);
181 
182 	if (hu->tx_skb) {
183 		kfree_skb(hu->tx_skb); hu->tx_skb = NULL;
184 	}
185 
186 	/* Flush any pending characters in the driver and discipline. */
187 	tty_ldisc_flush(tty);
188 	tty_driver_flush_buffer(tty);
189 
190 	if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
191 		hu->proto->flush(hu);
192 
193 	return 0;
194 }
195 
196 /* Close device */
197 static int hci_uart_close(struct hci_dev *hdev)
198 {
199 	BT_DBG("hdev %p", hdev);
200 
201 	if (!test_and_clear_bit(HCI_RUNNING, &hdev->flags))
202 		return 0;
203 
204 	hci_uart_flush(hdev);
205 	hdev->flush = NULL;
206 	return 0;
207 }
208 
209 /* Send frames from HCI layer */
210 static int hci_uart_send_frame(struct sk_buff *skb)
211 {
212 	struct hci_dev* hdev = (struct hci_dev *) skb->dev;
213 	struct tty_struct *tty;
214 	struct hci_uart *hu;
215 
216 	if (!hdev) {
217 		BT_ERR("Frame for unknown device (hdev=NULL)");
218 		return -ENODEV;
219 	}
220 
221 	if (!test_bit(HCI_RUNNING, &hdev->flags))
222 		return -EBUSY;
223 
224 	hu = (struct hci_uart *) hdev->driver_data;
225 	tty = hu->tty;
226 
227 	BT_DBG("%s: type %d len %d", hdev->name, bt_cb(skb)->pkt_type, skb->len);
228 
229 	hu->proto->enqueue(hu, skb);
230 
231 	hci_uart_tx_wakeup(hu);
232 
233 	return 0;
234 }
235 
236 static void hci_uart_destruct(struct hci_dev *hdev)
237 {
238 	if (!hdev)
239 		return;
240 
241 	BT_DBG("%s", hdev->name);
242 	kfree(hdev->driver_data);
243 }
244 
245 /* ------ LDISC part ------ */
246 /* hci_uart_tty_open
247  *
248  *     Called when line discipline changed to HCI_UART.
249  *
250  * Arguments:
251  *     tty    pointer to tty info structure
252  * Return Value:
253  *     0 if success, otherwise error code
254  */
255 static int hci_uart_tty_open(struct tty_struct *tty)
256 {
257 	struct hci_uart *hu = (void *) tty->disc_data;
258 
259 	BT_DBG("tty %p", tty);
260 
261 	if (hu)
262 		return -EEXIST;
263 
264 	if (!(hu = kzalloc(sizeof(struct hci_uart), GFP_KERNEL))) {
265 		BT_ERR("Can't allocate control structure");
266 		return -ENFILE;
267 	}
268 
269 	tty->disc_data = hu;
270 	hu->tty = tty;
271 	tty->receive_room = 65536;
272 
273 	spin_lock_init(&hu->rx_lock);
274 
275 	/* Flush any pending characters in the driver and line discipline. */
276 
277 	/* FIXME: why is this needed. Note don't use ldisc_ref here as the
278 	   open path is before the ldisc is referencable */
279 
280 	if (tty->ldisc->ops->flush_buffer)
281 		tty->ldisc->ops->flush_buffer(tty);
282 	tty_driver_flush_buffer(tty);
283 
284 	return 0;
285 }
286 
287 /* hci_uart_tty_close()
288  *
289  *    Called when the line discipline is changed to something
290  *    else, the tty is closed, or the tty detects a hangup.
291  */
292 static void hci_uart_tty_close(struct tty_struct *tty)
293 {
294 	struct hci_uart *hu = (void *)tty->disc_data;
295 
296 	BT_DBG("tty %p", tty);
297 
298 	/* Detach from the tty */
299 	tty->disc_data = NULL;
300 
301 	if (hu) {
302 		struct hci_dev *hdev = hu->hdev;
303 
304 		if (hdev)
305 			hci_uart_close(hdev);
306 
307 		if (test_and_clear_bit(HCI_UART_PROTO_SET, &hu->flags)) {
308 			hu->proto->close(hu);
309 			hci_unregister_dev(hdev);
310 			hci_free_dev(hdev);
311 		}
312 	}
313 }
314 
315 /* hci_uart_tty_wakeup()
316  *
317  *    Callback for transmit wakeup. Called when low level
318  *    device driver can accept more send data.
319  *
320  * Arguments:        tty    pointer to associated tty instance data
321  * Return Value:    None
322  */
323 static void hci_uart_tty_wakeup(struct tty_struct *tty)
324 {
325 	struct hci_uart *hu = (void *)tty->disc_data;
326 
327 	BT_DBG("");
328 
329 	if (!hu)
330 		return;
331 
332 	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
333 
334 	if (tty != hu->tty)
335 		return;
336 
337 	if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
338 		hci_uart_tx_wakeup(hu);
339 }
340 
341 /* hci_uart_tty_receive()
342  *
343  *     Called by tty low level driver when receive data is
344  *     available.
345  *
346  * Arguments:  tty          pointer to tty isntance data
347  *             data         pointer to received data
348  *             flags        pointer to flags for data
349  *             count        count of received data in bytes
350  *
351  * Return Value:    None
352  */
353 static void hci_uart_tty_receive(struct tty_struct *tty, const u8 *data, char *flags, int count)
354 {
355 	struct hci_uart *hu = (void *)tty->disc_data;
356 
357 	if (!hu || tty != hu->tty)
358 		return;
359 
360 	if (!test_bit(HCI_UART_PROTO_SET, &hu->flags))
361 		return;
362 
363 	spin_lock(&hu->rx_lock);
364 	hu->proto->recv(hu, (void *) data, count);
365 	hu->hdev->stat.byte_rx += count;
366 	spin_unlock(&hu->rx_lock);
367 
368 	tty_unthrottle(tty);
369 }
370 
371 static int hci_uart_register_dev(struct hci_uart *hu)
372 {
373 	struct hci_dev *hdev;
374 
375 	BT_DBG("");
376 
377 	/* Initialize and register HCI device */
378 	hdev = hci_alloc_dev();
379 	if (!hdev) {
380 		BT_ERR("Can't allocate HCI device");
381 		return -ENOMEM;
382 	}
383 
384 	hu->hdev = hdev;
385 
386 	hdev->type = HCI_UART;
387 	hdev->driver_data = hu;
388 
389 	hdev->open  = hci_uart_open;
390 	hdev->close = hci_uart_close;
391 	hdev->flush = hci_uart_flush;
392 	hdev->send  = hci_uart_send_frame;
393 	hdev->destruct = hci_uart_destruct;
394 
395 	hdev->owner = THIS_MODULE;
396 
397 	if (!reset)
398 		set_bit(HCI_QUIRK_NO_RESET, &hdev->quirks);
399 
400 	if (hci_register_dev(hdev) < 0) {
401 		BT_ERR("Can't register HCI device");
402 		hci_free_dev(hdev);
403 		return -ENODEV;
404 	}
405 
406 	return 0;
407 }
408 
409 static int hci_uart_set_proto(struct hci_uart *hu, int id)
410 {
411 	struct hci_uart_proto *p;
412 	int err;
413 
414 	p = hci_uart_get_proto(id);
415 	if (!p)
416 		return -EPROTONOSUPPORT;
417 
418 	err = p->open(hu);
419 	if (err)
420 		return err;
421 
422 	hu->proto = p;
423 
424 	err = hci_uart_register_dev(hu);
425 	if (err) {
426 		p->close(hu);
427 		return err;
428 	}
429 
430 	return 0;
431 }
432 
433 /* hci_uart_tty_ioctl()
434  *
435  *    Process IOCTL system call for the tty device.
436  *
437  * Arguments:
438  *
439  *    tty        pointer to tty instance data
440  *    file       pointer to open file object for device
441  *    cmd        IOCTL command code
442  *    arg        argument for IOCTL call (cmd dependent)
443  *
444  * Return Value:    Command dependent
445  */
446 static int hci_uart_tty_ioctl(struct tty_struct *tty, struct file * file,
447 					unsigned int cmd, unsigned long arg)
448 {
449 	struct hci_uart *hu = (void *)tty->disc_data;
450 	int err = 0;
451 
452 	BT_DBG("");
453 
454 	/* Verify the status of the device */
455 	if (!hu)
456 		return -EBADF;
457 
458 	switch (cmd) {
459 	case HCIUARTSETPROTO:
460 		if (!test_and_set_bit(HCI_UART_PROTO_SET, &hu->flags)) {
461 			err = hci_uart_set_proto(hu, arg);
462 			if (err) {
463 				clear_bit(HCI_UART_PROTO_SET, &hu->flags);
464 				return err;
465 			}
466 		} else
467 			return -EBUSY;
468 		break;
469 
470 	case HCIUARTGETPROTO:
471 		if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
472 			return hu->proto->id;
473 		return -EUNATCH;
474 
475 	case HCIUARTGETDEVICE:
476 		if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
477 			return hu->hdev->id;
478 		return -EUNATCH;
479 
480 	default:
481 		err = n_tty_ioctl_helper(tty, file, cmd, arg);
482 		break;
483 	};
484 
485 	return err;
486 }
487 
488 /*
489  * We don't provide read/write/poll interface for user space.
490  */
491 static ssize_t hci_uart_tty_read(struct tty_struct *tty, struct file *file,
492 					unsigned char __user *buf, size_t nr)
493 {
494 	return 0;
495 }
496 
497 static ssize_t hci_uart_tty_write(struct tty_struct *tty, struct file *file,
498 					const unsigned char *data, size_t count)
499 {
500 	return 0;
501 }
502 
503 static unsigned int hci_uart_tty_poll(struct tty_struct *tty,
504 					struct file *filp, poll_table *wait)
505 {
506 	return 0;
507 }
508 
509 static int __init hci_uart_init(void)
510 {
511 	static struct tty_ldisc_ops hci_uart_ldisc;
512 	int err;
513 
514 	BT_INFO("HCI UART driver ver %s", VERSION);
515 
516 	/* Register the tty discipline */
517 
518 	memset(&hci_uart_ldisc, 0, sizeof (hci_uart_ldisc));
519 	hci_uart_ldisc.magic		= TTY_LDISC_MAGIC;
520 	hci_uart_ldisc.name		= "n_hci";
521 	hci_uart_ldisc.open		= hci_uart_tty_open;
522 	hci_uart_ldisc.close		= hci_uart_tty_close;
523 	hci_uart_ldisc.read		= hci_uart_tty_read;
524 	hci_uart_ldisc.write		= hci_uart_tty_write;
525 	hci_uart_ldisc.ioctl		= hci_uart_tty_ioctl;
526 	hci_uart_ldisc.poll		= hci_uart_tty_poll;
527 	hci_uart_ldisc.receive_buf	= hci_uart_tty_receive;
528 	hci_uart_ldisc.write_wakeup	= hci_uart_tty_wakeup;
529 	hci_uart_ldisc.owner		= THIS_MODULE;
530 
531 	if ((err = tty_register_ldisc(N_HCI, &hci_uart_ldisc))) {
532 		BT_ERR("HCI line discipline registration failed. (%d)", err);
533 		return err;
534 	}
535 
536 #ifdef CONFIG_BT_HCIUART_H4
537 	h4_init();
538 #endif
539 #ifdef CONFIG_BT_HCIUART_BCSP
540 	bcsp_init();
541 #endif
542 #ifdef CONFIG_BT_HCIUART_LL
543 	ll_init();
544 #endif
545 
546 	return 0;
547 }
548 
549 static void __exit hci_uart_exit(void)
550 {
551 	int err;
552 
553 #ifdef CONFIG_BT_HCIUART_H4
554 	h4_deinit();
555 #endif
556 #ifdef CONFIG_BT_HCIUART_BCSP
557 	bcsp_deinit();
558 #endif
559 #ifdef CONFIG_BT_HCIUART_LL
560 	ll_deinit();
561 #endif
562 
563 	/* Release tty registration of line discipline */
564 	if ((err = tty_unregister_ldisc(N_HCI)))
565 		BT_ERR("Can't unregister HCI line discipline (%d)", err);
566 }
567 
568 module_init(hci_uart_init);
569 module_exit(hci_uart_exit);
570 
571 module_param(reset, bool, 0644);
572 MODULE_PARM_DESC(reset, "Send HCI reset command on initialization");
573 
574 MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
575 MODULE_DESCRIPTION("Bluetooth HCI UART driver ver " VERSION);
576 MODULE_VERSION(VERSION);
577 MODULE_LICENSE("GPL");
578 MODULE_ALIAS_LDISC(N_HCI);
579