xref: /linux/drivers/bluetooth/hci_ll.c (revision b2d0f5d5dc53532e6f07bc546a476a55ebdfe0f3)
1 /*
2  *  Texas Instruments' Bluetooth HCILL UART protocol
3  *
4  *  HCILL (HCI Low Level) is a Texas Instruments' power management
5  *  protocol extension to H4.
6  *
7  *  Copyright (C) 2007 Texas Instruments, Inc.
8  *
9  *  Written by Ohad Ben-Cohen <ohad@bencohen.org>
10  *
11  *  Acknowledgements:
12  *  This file is based on hci_h4.c, which was written
13  *  by Maxim Krasnyansky and Marcel Holtmann.
14  *
15  *  This program is free software; you can redistribute it and/or modify
16  *  it under the terms of the GNU General Public License version 2
17  *  as published by the Free Software Foundation
18  *
19  *  This program is distributed in the hope that it will be useful,
20  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
21  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22  *  GNU General Public License for more details.
23  *
24  *  You should have received a copy of the GNU General Public License
25  *  along with this program; if not, write to the Free Software
26  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
27  *
28  */
29 
30 #include <linux/module.h>
31 #include <linux/kernel.h>
32 
33 #include <linux/init.h>
34 #include <linux/sched.h>
35 #include <linux/types.h>
36 #include <linux/fcntl.h>
37 #include <linux/firmware.h>
38 #include <linux/interrupt.h>
39 #include <linux/ptrace.h>
40 #include <linux/poll.h>
41 
42 #include <linux/slab.h>
43 #include <linux/errno.h>
44 #include <linux/string.h>
45 #include <linux/signal.h>
46 #include <linux/ioctl.h>
47 #include <linux/of.h>
48 #include <linux/serdev.h>
49 #include <linux/skbuff.h>
50 #include <linux/ti_wilink_st.h>
51 #include <linux/clk.h>
52 
53 #include <net/bluetooth/bluetooth.h>
54 #include <net/bluetooth/hci_core.h>
55 #include <linux/gpio/consumer.h>
56 
57 #include "hci_uart.h"
58 
59 /* HCILL commands */
60 #define HCILL_GO_TO_SLEEP_IND	0x30
61 #define HCILL_GO_TO_SLEEP_ACK	0x31
62 #define HCILL_WAKE_UP_IND	0x32
63 #define HCILL_WAKE_UP_ACK	0x33
64 
65 /* HCILL receiver States */
66 #define HCILL_W4_PACKET_TYPE	0
67 #define HCILL_W4_EVENT_HDR	1
68 #define HCILL_W4_ACL_HDR	2
69 #define HCILL_W4_SCO_HDR	3
70 #define HCILL_W4_DATA		4
71 
72 /* HCILL states */
73 enum hcill_states_e {
74 	HCILL_ASLEEP,
75 	HCILL_ASLEEP_TO_AWAKE,
76 	HCILL_AWAKE,
77 	HCILL_AWAKE_TO_ASLEEP
78 };
79 
80 struct hcill_cmd {
81 	u8 cmd;
82 } __packed;
83 
84 struct ll_device {
85 	struct hci_uart hu;
86 	struct serdev_device *serdev;
87 	struct gpio_desc *enable_gpio;
88 	struct clk *ext_clk;
89 };
90 
91 struct ll_struct {
92 	unsigned long rx_state;
93 	unsigned long rx_count;
94 	struct sk_buff *rx_skb;
95 	struct sk_buff_head txq;
96 	spinlock_t hcill_lock;		/* HCILL state lock	*/
97 	unsigned long hcill_state;	/* HCILL power state	*/
98 	struct sk_buff_head tx_wait_q;	/* HCILL wait queue	*/
99 };
100 
101 /*
102  * Builds and sends an HCILL command packet.
103  * These are very simple packets with only 1 cmd byte
104  */
105 static int send_hcill_cmd(u8 cmd, struct hci_uart *hu)
106 {
107 	int err = 0;
108 	struct sk_buff *skb = NULL;
109 	struct ll_struct *ll = hu->priv;
110 	struct hcill_cmd *hcill_packet;
111 
112 	BT_DBG("hu %p cmd 0x%x", hu, cmd);
113 
114 	/* allocate packet */
115 	skb = bt_skb_alloc(1, GFP_ATOMIC);
116 	if (!skb) {
117 		BT_ERR("cannot allocate memory for HCILL packet");
118 		err = -ENOMEM;
119 		goto out;
120 	}
121 
122 	/* prepare packet */
123 	hcill_packet = skb_put(skb, 1);
124 	hcill_packet->cmd = cmd;
125 
126 	/* send packet */
127 	skb_queue_tail(&ll->txq, skb);
128 out:
129 	return err;
130 }
131 
132 /* Initialize protocol */
133 static int ll_open(struct hci_uart *hu)
134 {
135 	struct ll_struct *ll;
136 
137 	BT_DBG("hu %p", hu);
138 
139 	ll = kzalloc(sizeof(*ll), GFP_KERNEL);
140 	if (!ll)
141 		return -ENOMEM;
142 
143 	skb_queue_head_init(&ll->txq);
144 	skb_queue_head_init(&ll->tx_wait_q);
145 	spin_lock_init(&ll->hcill_lock);
146 
147 	ll->hcill_state = HCILL_AWAKE;
148 
149 	hu->priv = ll;
150 
151 	if (hu->serdev) {
152 		struct ll_device *lldev = serdev_device_get_drvdata(hu->serdev);
153 		serdev_device_open(hu->serdev);
154 		if (!IS_ERR(lldev->ext_clk))
155 			clk_prepare_enable(lldev->ext_clk);
156 	}
157 
158 	return 0;
159 }
160 
161 /* Flush protocol data */
162 static int ll_flush(struct hci_uart *hu)
163 {
164 	struct ll_struct *ll = hu->priv;
165 
166 	BT_DBG("hu %p", hu);
167 
168 	skb_queue_purge(&ll->tx_wait_q);
169 	skb_queue_purge(&ll->txq);
170 
171 	return 0;
172 }
173 
174 /* Close protocol */
175 static int ll_close(struct hci_uart *hu)
176 {
177 	struct ll_struct *ll = hu->priv;
178 
179 	BT_DBG("hu %p", hu);
180 
181 	skb_queue_purge(&ll->tx_wait_q);
182 	skb_queue_purge(&ll->txq);
183 
184 	kfree_skb(ll->rx_skb);
185 
186 	if (hu->serdev) {
187 		struct ll_device *lldev = serdev_device_get_drvdata(hu->serdev);
188 		gpiod_set_value_cansleep(lldev->enable_gpio, 0);
189 
190 		clk_disable_unprepare(lldev->ext_clk);
191 
192 		serdev_device_close(hu->serdev);
193 	}
194 
195 	hu->priv = NULL;
196 
197 	kfree(ll);
198 
199 	return 0;
200 }
201 
202 /*
203  * internal function, which does common work of the device wake up process:
204  * 1. places all pending packets (waiting in tx_wait_q list) in txq list.
205  * 2. changes internal state to HCILL_AWAKE.
206  * Note: assumes that hcill_lock spinlock is taken,
207  * shouldn't be called otherwise!
208  */
209 static void __ll_do_awake(struct ll_struct *ll)
210 {
211 	struct sk_buff *skb = NULL;
212 
213 	while ((skb = skb_dequeue(&ll->tx_wait_q)))
214 		skb_queue_tail(&ll->txq, skb);
215 
216 	ll->hcill_state = HCILL_AWAKE;
217 }
218 
219 /*
220  * Called upon a wake-up-indication from the device
221  */
222 static void ll_device_want_to_wakeup(struct hci_uart *hu)
223 {
224 	unsigned long flags;
225 	struct ll_struct *ll = hu->priv;
226 
227 	BT_DBG("hu %p", hu);
228 
229 	/* lock hcill state */
230 	spin_lock_irqsave(&ll->hcill_lock, flags);
231 
232 	switch (ll->hcill_state) {
233 	case HCILL_ASLEEP_TO_AWAKE:
234 		/*
235 		 * This state means that both the host and the BRF chip
236 		 * have simultaneously sent a wake-up-indication packet.
237 		 * Traditionally, in this case, receiving a wake-up-indication
238 		 * was enough and an additional wake-up-ack wasn't needed.
239 		 * This has changed with the BRF6350, which does require an
240 		 * explicit wake-up-ack. Other BRF versions, which do not
241 		 * require an explicit ack here, do accept it, thus it is
242 		 * perfectly safe to always send one.
243 		 */
244 		BT_DBG("dual wake-up-indication");
245 		/* fall through */
246 	case HCILL_ASLEEP:
247 		/* acknowledge device wake up */
248 		if (send_hcill_cmd(HCILL_WAKE_UP_ACK, hu) < 0) {
249 			BT_ERR("cannot acknowledge device wake up");
250 			goto out;
251 		}
252 		break;
253 	default:
254 		/* any other state is illegal */
255 		BT_ERR("received HCILL_WAKE_UP_IND in state %ld", ll->hcill_state);
256 		break;
257 	}
258 
259 	/* send pending packets and change state to HCILL_AWAKE */
260 	__ll_do_awake(ll);
261 
262 out:
263 	spin_unlock_irqrestore(&ll->hcill_lock, flags);
264 
265 	/* actually send the packets */
266 	hci_uart_tx_wakeup(hu);
267 }
268 
269 /*
270  * Called upon a sleep-indication from the device
271  */
272 static void ll_device_want_to_sleep(struct hci_uart *hu)
273 {
274 	unsigned long flags;
275 	struct ll_struct *ll = hu->priv;
276 
277 	BT_DBG("hu %p", hu);
278 
279 	/* lock hcill state */
280 	spin_lock_irqsave(&ll->hcill_lock, flags);
281 
282 	/* sanity check */
283 	if (ll->hcill_state != HCILL_AWAKE)
284 		BT_ERR("ERR: HCILL_GO_TO_SLEEP_IND in state %ld", ll->hcill_state);
285 
286 	/* acknowledge device sleep */
287 	if (send_hcill_cmd(HCILL_GO_TO_SLEEP_ACK, hu) < 0) {
288 		BT_ERR("cannot acknowledge device sleep");
289 		goto out;
290 	}
291 
292 	/* update state */
293 	ll->hcill_state = HCILL_ASLEEP;
294 
295 out:
296 	spin_unlock_irqrestore(&ll->hcill_lock, flags);
297 
298 	/* actually send the sleep ack packet */
299 	hci_uart_tx_wakeup(hu);
300 }
301 
302 /*
303  * Called upon wake-up-acknowledgement from the device
304  */
305 static void ll_device_woke_up(struct hci_uart *hu)
306 {
307 	unsigned long flags;
308 	struct ll_struct *ll = hu->priv;
309 
310 	BT_DBG("hu %p", hu);
311 
312 	/* lock hcill state */
313 	spin_lock_irqsave(&ll->hcill_lock, flags);
314 
315 	/* sanity check */
316 	if (ll->hcill_state != HCILL_ASLEEP_TO_AWAKE)
317 		BT_ERR("received HCILL_WAKE_UP_ACK in state %ld", ll->hcill_state);
318 
319 	/* send pending packets and change state to HCILL_AWAKE */
320 	__ll_do_awake(ll);
321 
322 	spin_unlock_irqrestore(&ll->hcill_lock, flags);
323 
324 	/* actually send the packets */
325 	hci_uart_tx_wakeup(hu);
326 }
327 
328 /* Enqueue frame for transmittion (padding, crc, etc) */
329 /* may be called from two simultaneous tasklets */
330 static int ll_enqueue(struct hci_uart *hu, struct sk_buff *skb)
331 {
332 	unsigned long flags = 0;
333 	struct ll_struct *ll = hu->priv;
334 
335 	BT_DBG("hu %p skb %p", hu, skb);
336 
337 	/* Prepend skb with frame type */
338 	memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);
339 
340 	/* lock hcill state */
341 	spin_lock_irqsave(&ll->hcill_lock, flags);
342 
343 	/* act according to current state */
344 	switch (ll->hcill_state) {
345 	case HCILL_AWAKE:
346 		BT_DBG("device awake, sending normally");
347 		skb_queue_tail(&ll->txq, skb);
348 		break;
349 	case HCILL_ASLEEP:
350 		BT_DBG("device asleep, waking up and queueing packet");
351 		/* save packet for later */
352 		skb_queue_tail(&ll->tx_wait_q, skb);
353 		/* awake device */
354 		if (send_hcill_cmd(HCILL_WAKE_UP_IND, hu) < 0) {
355 			BT_ERR("cannot wake up device");
356 			break;
357 		}
358 		ll->hcill_state = HCILL_ASLEEP_TO_AWAKE;
359 		break;
360 	case HCILL_ASLEEP_TO_AWAKE:
361 		BT_DBG("device waking up, queueing packet");
362 		/* transient state; just keep packet for later */
363 		skb_queue_tail(&ll->tx_wait_q, skb);
364 		break;
365 	default:
366 		BT_ERR("illegal hcill state: %ld (losing packet)", ll->hcill_state);
367 		kfree_skb(skb);
368 		break;
369 	}
370 
371 	spin_unlock_irqrestore(&ll->hcill_lock, flags);
372 
373 	return 0;
374 }
375 
376 static inline int ll_check_data_len(struct hci_dev *hdev, struct ll_struct *ll, int len)
377 {
378 	int room = skb_tailroom(ll->rx_skb);
379 
380 	BT_DBG("len %d room %d", len, room);
381 
382 	if (!len) {
383 		hci_recv_frame(hdev, ll->rx_skb);
384 	} else if (len > room) {
385 		BT_ERR("Data length is too large");
386 		kfree_skb(ll->rx_skb);
387 	} else {
388 		ll->rx_state = HCILL_W4_DATA;
389 		ll->rx_count = len;
390 		return len;
391 	}
392 
393 	ll->rx_state = HCILL_W4_PACKET_TYPE;
394 	ll->rx_skb   = NULL;
395 	ll->rx_count = 0;
396 
397 	return 0;
398 }
399 
400 /* Recv data */
401 static int ll_recv(struct hci_uart *hu, const void *data, int count)
402 {
403 	struct ll_struct *ll = hu->priv;
404 	const char *ptr;
405 	struct hci_event_hdr *eh;
406 	struct hci_acl_hdr   *ah;
407 	struct hci_sco_hdr   *sh;
408 	int len, type, dlen;
409 
410 	BT_DBG("hu %p count %d rx_state %ld rx_count %ld", hu, count, ll->rx_state, ll->rx_count);
411 
412 	ptr = data;
413 	while (count) {
414 		if (ll->rx_count) {
415 			len = min_t(unsigned int, ll->rx_count, count);
416 			skb_put_data(ll->rx_skb, ptr, len);
417 			ll->rx_count -= len; count -= len; ptr += len;
418 
419 			if (ll->rx_count)
420 				continue;
421 
422 			switch (ll->rx_state) {
423 			case HCILL_W4_DATA:
424 				BT_DBG("Complete data");
425 				hci_recv_frame(hu->hdev, ll->rx_skb);
426 
427 				ll->rx_state = HCILL_W4_PACKET_TYPE;
428 				ll->rx_skb = NULL;
429 				continue;
430 
431 			case HCILL_W4_EVENT_HDR:
432 				eh = hci_event_hdr(ll->rx_skb);
433 
434 				BT_DBG("Event header: evt 0x%2.2x plen %d", eh->evt, eh->plen);
435 
436 				ll_check_data_len(hu->hdev, ll, eh->plen);
437 				continue;
438 
439 			case HCILL_W4_ACL_HDR:
440 				ah = hci_acl_hdr(ll->rx_skb);
441 				dlen = __le16_to_cpu(ah->dlen);
442 
443 				BT_DBG("ACL header: dlen %d", dlen);
444 
445 				ll_check_data_len(hu->hdev, ll, dlen);
446 				continue;
447 
448 			case HCILL_W4_SCO_HDR:
449 				sh = hci_sco_hdr(ll->rx_skb);
450 
451 				BT_DBG("SCO header: dlen %d", sh->dlen);
452 
453 				ll_check_data_len(hu->hdev, ll, sh->dlen);
454 				continue;
455 			}
456 		}
457 
458 		/* HCILL_W4_PACKET_TYPE */
459 		switch (*ptr) {
460 		case HCI_EVENT_PKT:
461 			BT_DBG("Event packet");
462 			ll->rx_state = HCILL_W4_EVENT_HDR;
463 			ll->rx_count = HCI_EVENT_HDR_SIZE;
464 			type = HCI_EVENT_PKT;
465 			break;
466 
467 		case HCI_ACLDATA_PKT:
468 			BT_DBG("ACL packet");
469 			ll->rx_state = HCILL_W4_ACL_HDR;
470 			ll->rx_count = HCI_ACL_HDR_SIZE;
471 			type = HCI_ACLDATA_PKT;
472 			break;
473 
474 		case HCI_SCODATA_PKT:
475 			BT_DBG("SCO packet");
476 			ll->rx_state = HCILL_W4_SCO_HDR;
477 			ll->rx_count = HCI_SCO_HDR_SIZE;
478 			type = HCI_SCODATA_PKT;
479 			break;
480 
481 		/* HCILL signals */
482 		case HCILL_GO_TO_SLEEP_IND:
483 			BT_DBG("HCILL_GO_TO_SLEEP_IND packet");
484 			ll_device_want_to_sleep(hu);
485 			ptr++; count--;
486 			continue;
487 
488 		case HCILL_GO_TO_SLEEP_ACK:
489 			/* shouldn't happen */
490 			BT_ERR("received HCILL_GO_TO_SLEEP_ACK (in state %ld)", ll->hcill_state);
491 			ptr++; count--;
492 			continue;
493 
494 		case HCILL_WAKE_UP_IND:
495 			BT_DBG("HCILL_WAKE_UP_IND packet");
496 			ll_device_want_to_wakeup(hu);
497 			ptr++; count--;
498 			continue;
499 
500 		case HCILL_WAKE_UP_ACK:
501 			BT_DBG("HCILL_WAKE_UP_ACK packet");
502 			ll_device_woke_up(hu);
503 			ptr++; count--;
504 			continue;
505 
506 		default:
507 			BT_ERR("Unknown HCI packet type %2.2x", (__u8)*ptr);
508 			hu->hdev->stat.err_rx++;
509 			ptr++; count--;
510 			continue;
511 		}
512 
513 		ptr++; count--;
514 
515 		/* Allocate packet */
516 		ll->rx_skb = bt_skb_alloc(HCI_MAX_FRAME_SIZE, GFP_ATOMIC);
517 		if (!ll->rx_skb) {
518 			BT_ERR("Can't allocate mem for new packet");
519 			ll->rx_state = HCILL_W4_PACKET_TYPE;
520 			ll->rx_count = 0;
521 			return -ENOMEM;
522 		}
523 
524 		hci_skb_pkt_type(ll->rx_skb) = type;
525 	}
526 
527 	return count;
528 }
529 
530 static struct sk_buff *ll_dequeue(struct hci_uart *hu)
531 {
532 	struct ll_struct *ll = hu->priv;
533 	return skb_dequeue(&ll->txq);
534 }
535 
536 #if IS_ENABLED(CONFIG_SERIAL_DEV_BUS)
537 static int read_local_version(struct hci_dev *hdev)
538 {
539 	int err = 0;
540 	unsigned short version = 0;
541 	struct sk_buff *skb;
542 	struct hci_rp_read_local_version *ver;
543 
544 	skb = __hci_cmd_sync(hdev, HCI_OP_READ_LOCAL_VERSION, 0, NULL, HCI_INIT_TIMEOUT);
545 	if (IS_ERR(skb)) {
546 		bt_dev_err(hdev, "Reading TI version information failed (%ld)",
547 			   PTR_ERR(skb));
548 		return PTR_ERR(skb);
549 	}
550 	if (skb->len != sizeof(*ver)) {
551 		err = -EILSEQ;
552 		goto out;
553 	}
554 
555 	ver = (struct hci_rp_read_local_version *)skb->data;
556 	if (le16_to_cpu(ver->manufacturer) != 13) {
557 		err = -ENODEV;
558 		goto out;
559 	}
560 
561 	version = le16_to_cpu(ver->lmp_subver);
562 
563 out:
564 	if (err) bt_dev_err(hdev, "Failed to read TI version info: %d", err);
565 	kfree_skb(skb);
566 	return err ? err : version;
567 }
568 
569 /**
570  * download_firmware -
571  *	internal function which parses through the .bts firmware
572  *	script file intreprets SEND, DELAY actions only as of now
573  */
574 static int download_firmware(struct ll_device *lldev)
575 {
576 	unsigned short chip, min_ver, maj_ver;
577 	int version, err, len;
578 	unsigned char *ptr, *action_ptr;
579 	unsigned char bts_scr_name[40];	/* 40 char long bts scr name? */
580 	const struct firmware *fw;
581 	struct sk_buff *skb;
582 	struct hci_command *cmd;
583 
584 	version = read_local_version(lldev->hu.hdev);
585 	if (version < 0)
586 		return version;
587 
588 	chip = (version & 0x7C00) >> 10;
589 	min_ver = (version & 0x007F);
590 	maj_ver = (version & 0x0380) >> 7;
591 	if (version & 0x8000)
592 		maj_ver |= 0x0008;
593 
594 	snprintf(bts_scr_name, sizeof(bts_scr_name),
595 		 "ti-connectivity/TIInit_%d.%d.%d.bts",
596 		 chip, maj_ver, min_ver);
597 
598 	err = request_firmware(&fw, bts_scr_name, &lldev->serdev->dev);
599 	if (err || !fw->data || !fw->size) {
600 		bt_dev_err(lldev->hu.hdev, "request_firmware failed(errno %d) for %s",
601 			   err, bts_scr_name);
602 		return -EINVAL;
603 	}
604 	ptr = (void *)fw->data;
605 	len = fw->size;
606 	/* bts_header to remove out magic number and
607 	 * version
608 	 */
609 	ptr += sizeof(struct bts_header);
610 	len -= sizeof(struct bts_header);
611 
612 	while (len > 0 && ptr) {
613 		bt_dev_dbg(lldev->hu.hdev, " action size %d, type %d ",
614 			   ((struct bts_action *)ptr)->size,
615 			   ((struct bts_action *)ptr)->type);
616 
617 		action_ptr = &(((struct bts_action *)ptr)->data[0]);
618 
619 		switch (((struct bts_action *)ptr)->type) {
620 		case ACTION_SEND_COMMAND:	/* action send */
621 			bt_dev_dbg(lldev->hu.hdev, "S");
622 			cmd = (struct hci_command *)action_ptr;
623 			if (cmd->opcode == 0xff36) {
624 				/* ignore remote change
625 				 * baud rate HCI VS command
626 				 */
627 				bt_dev_warn(lldev->hu.hdev, "change remote baud rate command in firmware");
628 				break;
629 			}
630 			if (cmd->prefix != 1)
631 				bt_dev_dbg(lldev->hu.hdev, "command type %d\n", cmd->prefix);
632 
633 			skb = __hci_cmd_sync(lldev->hu.hdev, cmd->opcode, cmd->plen, &cmd->speed, HCI_INIT_TIMEOUT);
634 			if (IS_ERR(skb)) {
635 				bt_dev_err(lldev->hu.hdev, "send command failed\n");
636 				err = PTR_ERR(skb);
637 				goto out_rel_fw;
638 			}
639 			kfree_skb(skb);
640 			break;
641 		case ACTION_WAIT_EVENT:  /* wait */
642 			/* no need to wait as command was synchronous */
643 			bt_dev_dbg(lldev->hu.hdev, "W");
644 			break;
645 		case ACTION_DELAY:	/* sleep */
646 			bt_dev_info(lldev->hu.hdev, "sleep command in scr");
647 			mdelay(((struct bts_action_delay *)action_ptr)->msec);
648 			break;
649 		}
650 		len -= (sizeof(struct bts_action) +
651 			((struct bts_action *)ptr)->size);
652 		ptr += sizeof(struct bts_action) +
653 			((struct bts_action *)ptr)->size;
654 	}
655 
656 out_rel_fw:
657 	/* fw download complete */
658 	release_firmware(fw);
659 	return err;
660 }
661 
662 static int ll_setup(struct hci_uart *hu)
663 {
664 	int err, retry = 3;
665 	struct ll_device *lldev;
666 	struct serdev_device *serdev = hu->serdev;
667 	u32 speed;
668 
669 	if (!serdev)
670 		return 0;
671 
672 	lldev = serdev_device_get_drvdata(serdev);
673 
674 	serdev_device_set_flow_control(serdev, true);
675 
676 	do {
677 		/* Configure BT_EN to HIGH state */
678 		gpiod_set_value_cansleep(lldev->enable_gpio, 0);
679 		msleep(5);
680 		gpiod_set_value_cansleep(lldev->enable_gpio, 1);
681 		msleep(100);
682 
683 		err = download_firmware(lldev);
684 		if (!err)
685 			break;
686 
687 		/* Toggle BT_EN and retry */
688 		bt_dev_err(hu->hdev, "download firmware failed, retrying...");
689 	} while (retry--);
690 
691 	if (err)
692 		return err;
693 
694 	/* Operational speed if any */
695 	if (hu->oper_speed)
696 		speed = hu->oper_speed;
697 	else if (hu->proto->oper_speed)
698 		speed = hu->proto->oper_speed;
699 	else
700 		speed = 0;
701 
702 	if (speed) {
703 		struct sk_buff *skb = __hci_cmd_sync(hu->hdev, 0xff36, sizeof(speed), &speed, HCI_INIT_TIMEOUT);
704 		if (!IS_ERR(skb)) {
705 			kfree_skb(skb);
706 			serdev_device_set_baudrate(serdev, speed);
707 		}
708 	}
709 
710 	return 0;
711 }
712 
713 static const struct hci_uart_proto llp;
714 
715 static int hci_ti_probe(struct serdev_device *serdev)
716 {
717 	struct hci_uart *hu;
718 	struct ll_device *lldev;
719 	u32 max_speed = 3000000;
720 
721 	lldev = devm_kzalloc(&serdev->dev, sizeof(struct ll_device), GFP_KERNEL);
722 	if (!lldev)
723 		return -ENOMEM;
724 	hu = &lldev->hu;
725 
726 	serdev_device_set_drvdata(serdev, lldev);
727 	lldev->serdev = hu->serdev = serdev;
728 
729 	lldev->enable_gpio = devm_gpiod_get_optional(&serdev->dev, "enable", GPIOD_OUT_LOW);
730 	if (IS_ERR(lldev->enable_gpio))
731 		return PTR_ERR(lldev->enable_gpio);
732 
733 	lldev->ext_clk = devm_clk_get(&serdev->dev, "ext_clock");
734 	if (IS_ERR(lldev->ext_clk) && PTR_ERR(lldev->ext_clk) != -ENOENT)
735 		return PTR_ERR(lldev->ext_clk);
736 
737 	of_property_read_u32(serdev->dev.of_node, "max-speed", &max_speed);
738 	hci_uart_set_speeds(hu, 115200, max_speed);
739 
740 	return hci_uart_register_device(hu, &llp);
741 }
742 
743 static void hci_ti_remove(struct serdev_device *serdev)
744 {
745 	struct ll_device *lldev = serdev_device_get_drvdata(serdev);
746 
747 	hci_uart_unregister_device(&lldev->hu);
748 }
749 
750 static const struct of_device_id hci_ti_of_match[] = {
751 	{ .compatible = "ti,wl1271-st" },
752 	{ .compatible = "ti,wl1273-st" },
753 	{ .compatible = "ti,wl1281-st" },
754 	{ .compatible = "ti,wl1283-st" },
755 	{ .compatible = "ti,wl1285-st" },
756 	{ .compatible = "ti,wl1801-st" },
757 	{ .compatible = "ti,wl1805-st" },
758 	{ .compatible = "ti,wl1807-st" },
759 	{ .compatible = "ti,wl1831-st" },
760 	{ .compatible = "ti,wl1835-st" },
761 	{ .compatible = "ti,wl1837-st" },
762 	{},
763 };
764 MODULE_DEVICE_TABLE(of, hci_ti_of_match);
765 
766 static struct serdev_device_driver hci_ti_drv = {
767 	.driver		= {
768 		.name	= "hci-ti",
769 		.of_match_table = of_match_ptr(hci_ti_of_match),
770 	},
771 	.probe	= hci_ti_probe,
772 	.remove	= hci_ti_remove,
773 };
774 #else
775 #define ll_setup NULL
776 #endif
777 
778 static const struct hci_uart_proto llp = {
779 	.id		= HCI_UART_LL,
780 	.name		= "LL",
781 	.setup		= ll_setup,
782 	.open		= ll_open,
783 	.close		= ll_close,
784 	.recv		= ll_recv,
785 	.enqueue	= ll_enqueue,
786 	.dequeue	= ll_dequeue,
787 	.flush		= ll_flush,
788 };
789 
790 int __init ll_init(void)
791 {
792 	serdev_device_driver_register(&hci_ti_drv);
793 
794 	return hci_uart_register_proto(&llp);
795 }
796 
797 int __exit ll_deinit(void)
798 {
799 	serdev_device_driver_unregister(&hci_ti_drv);
800 
801 	return hci_uart_unregister_proto(&llp);
802 }
803