xref: /linux/drivers/bluetooth/hci_nokia.c (revision e58e871becec2d3b04ed91c0c16fe8deac9c9dfa)
1 /*
2  *  Bluetooth HCI UART H4 driver with Nokia Extensions AKA Nokia H4+
3  *
4  *  Copyright (C) 2015 Marcel Holtmann <marcel@holtmann.org>
5  *  Copyright (C) 2015-2017 Sebastian Reichel <sre@kernel.org>
6  *
7  *  This program is free software; you can redistribute it and/or modify
8  *  it under the terms of the GNU General Public License as published by
9  *  the Free Software Foundation; either version 2 of the License, or
10  *  (at your option) any later version.
11  *
12  *  This program is distributed in the hope that it will be useful,
13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  *  GNU General Public License for more details.
16  */
17 
18 #include <linux/clk.h>
19 #include <linux/errno.h>
20 #include <linux/firmware.h>
21 #include <linux/gpio/consumer.h>
22 #include <linux/interrupt.h>
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/of.h>
26 #include <linux/pm_runtime.h>
27 #include <linux/serdev.h>
28 #include <linux/skbuff.h>
29 #include <linux/slab.h>
30 #include <linux/string.h>
31 #include <linux/types.h>
32 #include <linux/unaligned/le_struct.h>
33 #include <net/bluetooth/bluetooth.h>
34 #include <net/bluetooth/hci_core.h>
35 
36 #include "hci_uart.h"
37 #include "btbcm.h"
38 
39 #define VERSION "0.1"
40 
41 #define NOKIA_ID_BCM2048	0x04
42 #define NOKIA_ID_TI1271		0x31
43 
44 #define FIRMWARE_BCM2048	"nokia/bcmfw.bin"
45 #define FIRMWARE_TI1271		"nokia/ti1273.bin"
46 
47 #define HCI_NOKIA_NEG_PKT	0x06
48 #define HCI_NOKIA_ALIVE_PKT	0x07
49 #define HCI_NOKIA_RADIO_PKT	0x08
50 
51 #define HCI_NOKIA_NEG_HDR_SIZE		1
52 #define HCI_NOKIA_MAX_NEG_SIZE		255
53 #define HCI_NOKIA_ALIVE_HDR_SIZE	1
54 #define HCI_NOKIA_MAX_ALIVE_SIZE	255
55 #define HCI_NOKIA_RADIO_HDR_SIZE	2
56 #define HCI_NOKIA_MAX_RADIO_SIZE	255
57 
58 #define NOKIA_PROTO_PKT		0x44
59 #define NOKIA_PROTO_BYTE	0x4c
60 
61 #define NOKIA_NEG_REQ		0x00
62 #define NOKIA_NEG_ACK		0x20
63 #define NOKIA_NEG_NAK		0x40
64 
65 #define H4_TYPE_SIZE		1
66 
67 #define NOKIA_RECV_ALIVE \
68 	.type = HCI_NOKIA_ALIVE_PKT, \
69 	.hlen = HCI_NOKIA_ALIVE_HDR_SIZE, \
70 	.loff = 0, \
71 	.lsize = 1, \
72 	.maxlen = HCI_NOKIA_MAX_ALIVE_SIZE \
73 
74 #define NOKIA_RECV_NEG \
75 	.type = HCI_NOKIA_NEG_PKT, \
76 	.hlen = HCI_NOKIA_NEG_HDR_SIZE, \
77 	.loff = 0, \
78 	.lsize = 1, \
79 	.maxlen = HCI_NOKIA_MAX_NEG_SIZE \
80 
81 #define NOKIA_RECV_RADIO \
82 	.type = HCI_NOKIA_RADIO_PKT, \
83 	.hlen = HCI_NOKIA_RADIO_HDR_SIZE, \
84 	.loff = 1, \
85 	.lsize = 1, \
86 	.maxlen = HCI_NOKIA_MAX_RADIO_SIZE \
87 
88 struct hci_nokia_neg_hdr {
89 	u8	dlen;
90 } __packed;
91 
92 struct hci_nokia_neg_cmd {
93 	u8	ack;
94 	u16	baud;
95 	u16	unused1;
96 	u8	proto;
97 	u16	sys_clk;
98 	u16	unused2;
99 } __packed;
100 
101 #define NOKIA_ALIVE_REQ   0x55
102 #define NOKIA_ALIVE_RESP  0xcc
103 
104 struct hci_nokia_alive_hdr {
105 	u8	dlen;
106 } __packed;
107 
108 struct hci_nokia_alive_pkt {
109 	u8	mid;
110 	u8	unused;
111 } __packed;
112 
113 struct hci_nokia_neg_evt {
114 	u8	ack;
115 	u16	baud;
116 	u16	unused1;
117 	u8	proto;
118 	u16	sys_clk;
119 	u16	unused2;
120 	u8	man_id;
121 	u8	ver_id;
122 } __packed;
123 
124 #define MAX_BAUD_RATE		3692300
125 #define SETUP_BAUD_RATE		921600
126 #define INIT_BAUD_RATE		120000
127 
128 struct hci_nokia_radio_hdr {
129 	u8	evt;
130 	u8	dlen;
131 } __packed;
132 
133 struct nokia_bt_dev {
134 	struct hci_uart hu;
135 	struct serdev_device *serdev;
136 
137 	struct gpio_desc *reset;
138 	struct gpio_desc *wakeup_host;
139 	struct gpio_desc *wakeup_bt;
140 	unsigned long sysclk_speed;
141 
142 	int wake_irq;
143 	struct sk_buff *rx_skb;
144 	struct sk_buff_head txq;
145 	bdaddr_t bdaddr;
146 
147 	int init_error;
148 	struct completion init_completion;
149 
150 	u8 man_id;
151 	u8 ver_id;
152 
153 	bool initialized;
154 	bool tx_enabled;
155 	bool rx_enabled;
156 };
157 
158 static int nokia_enqueue(struct hci_uart *hu, struct sk_buff *skb);
159 
160 static void nokia_flow_control(struct serdev_device *serdev, bool enable)
161 {
162 	if (enable) {
163 		serdev_device_set_rts(serdev, true);
164 		serdev_device_set_flow_control(serdev, true);
165 	} else {
166 		serdev_device_set_flow_control(serdev, false);
167 		serdev_device_set_rts(serdev, false);
168 	}
169 }
170 
171 static irqreturn_t wakeup_handler(int irq, void *data)
172 {
173 	struct nokia_bt_dev *btdev = data;
174 	struct device *dev = &btdev->serdev->dev;
175 	int wake_state = gpiod_get_value(btdev->wakeup_host);
176 
177 	if (btdev->rx_enabled == wake_state)
178 		return IRQ_HANDLED;
179 
180 	if (wake_state)
181 		pm_runtime_get(dev);
182 	else
183 		pm_runtime_put(dev);
184 
185 	btdev->rx_enabled = wake_state;
186 
187 	return IRQ_HANDLED;
188 }
189 
190 static int nokia_reset(struct hci_uart *hu)
191 {
192 	struct nokia_bt_dev *btdev = hu->priv;
193 	struct device *dev = &btdev->serdev->dev;
194 	int err;
195 
196 	/* reset routine */
197 	gpiod_set_value_cansleep(btdev->reset, 1);
198 	gpiod_set_value_cansleep(btdev->wakeup_bt, 1);
199 
200 	msleep(100);
201 
202 	/* safety check */
203 	err = gpiod_get_value_cansleep(btdev->wakeup_host);
204 	if (err == 1) {
205 		dev_err(dev, "reset: host wakeup not low!");
206 		return -EPROTO;
207 	}
208 
209 	/* flush queue */
210 	serdev_device_write_flush(btdev->serdev);
211 
212 	/* init uart */
213 	nokia_flow_control(btdev->serdev, false);
214 	serdev_device_set_baudrate(btdev->serdev, INIT_BAUD_RATE);
215 
216 	gpiod_set_value_cansleep(btdev->reset, 0);
217 
218 	/* wait for cts */
219 	err = serdev_device_wait_for_cts(btdev->serdev, true, 200);
220 	if (err < 0) {
221 		dev_err(dev, "CTS not received: %d", err);
222 		return err;
223 	}
224 
225 	nokia_flow_control(btdev->serdev, true);
226 
227 	return 0;
228 }
229 
230 static int nokia_send_alive_packet(struct hci_uart *hu)
231 {
232 	struct nokia_bt_dev *btdev = hu->priv;
233 	struct device *dev = &btdev->serdev->dev;
234 	struct hci_nokia_alive_hdr *hdr;
235 	struct hci_nokia_alive_pkt *pkt;
236 	struct sk_buff *skb;
237 	int len;
238 
239 	init_completion(&btdev->init_completion);
240 
241 	len = H4_TYPE_SIZE + sizeof(*hdr) + sizeof(*pkt);
242 	skb = bt_skb_alloc(len, GFP_KERNEL);
243 	if (!skb)
244 		return -ENOMEM;
245 
246 	hci_skb_pkt_type(skb) = HCI_NOKIA_ALIVE_PKT;
247 	memset(skb->data, 0x00, len);
248 
249 	hdr = (struct hci_nokia_alive_hdr *)skb_put(skb, sizeof(*hdr));
250 	hdr->dlen = sizeof(*pkt);
251 	pkt = (struct hci_nokia_alive_pkt *)skb_put(skb, sizeof(*pkt));
252 	pkt->mid = NOKIA_ALIVE_REQ;
253 
254 	nokia_enqueue(hu, skb);
255 	hci_uart_tx_wakeup(hu);
256 
257 	dev_dbg(dev, "Alive sent");
258 
259 	if (!wait_for_completion_interruptible_timeout(&btdev->init_completion,
260 		msecs_to_jiffies(1000))) {
261 		return -ETIMEDOUT;
262 	}
263 
264 	if (btdev->init_error < 0)
265 		return btdev->init_error;
266 
267 	return 0;
268 }
269 
270 static int nokia_send_negotiation(struct hci_uart *hu)
271 {
272 	struct nokia_bt_dev *btdev = hu->priv;
273 	struct device *dev = &btdev->serdev->dev;
274 	struct hci_nokia_neg_cmd *neg_cmd;
275 	struct hci_nokia_neg_hdr *neg_hdr;
276 	struct sk_buff *skb;
277 	int len, err;
278 	u16 baud = DIV_ROUND_CLOSEST(btdev->sysclk_speed * 10, SETUP_BAUD_RATE);
279 	int sysclk = btdev->sysclk_speed / 1000;
280 
281 	len = H4_TYPE_SIZE + sizeof(*neg_hdr) + sizeof(*neg_cmd);
282 	skb = bt_skb_alloc(len, GFP_KERNEL);
283 	if (!skb)
284 		return -ENOMEM;
285 
286 	hci_skb_pkt_type(skb) = HCI_NOKIA_NEG_PKT;
287 
288 	neg_hdr = (struct hci_nokia_neg_hdr *)skb_put(skb, sizeof(*neg_hdr));
289 	neg_hdr->dlen = sizeof(*neg_cmd);
290 
291 	neg_cmd = (struct hci_nokia_neg_cmd *)skb_put(skb, sizeof(*neg_cmd));
292 	neg_cmd->ack = NOKIA_NEG_REQ;
293 	neg_cmd->baud = cpu_to_le16(baud);
294 	neg_cmd->unused1 = 0x0000;
295 	neg_cmd->proto = NOKIA_PROTO_BYTE;
296 	neg_cmd->sys_clk = cpu_to_le16(sysclk);
297 	neg_cmd->unused2 = 0x0000;
298 
299 	btdev->init_error = 0;
300 	init_completion(&btdev->init_completion);
301 
302 	nokia_enqueue(hu, skb);
303 	hci_uart_tx_wakeup(hu);
304 
305 	dev_dbg(dev, "Negotiation sent");
306 
307 	if (!wait_for_completion_interruptible_timeout(&btdev->init_completion,
308 		msecs_to_jiffies(10000))) {
309 		return -ETIMEDOUT;
310 	}
311 
312 	if (btdev->init_error < 0)
313 		return btdev->init_error;
314 
315 	/* Change to previously negotiated speed. Flow Control
316 	 * is disabled until bluetooth adapter is ready to avoid
317 	 * broken bytes being received.
318 	 */
319 	nokia_flow_control(btdev->serdev, false);
320 	serdev_device_set_baudrate(btdev->serdev, SETUP_BAUD_RATE);
321 	err = serdev_device_wait_for_cts(btdev->serdev, true, 200);
322 	if (err < 0) {
323 		dev_err(dev, "CTS not received: %d", err);
324 		return err;
325 	}
326 	nokia_flow_control(btdev->serdev, true);
327 
328 	dev_dbg(dev, "Negotiation successful");
329 
330 	return 0;
331 }
332 
333 static int nokia_setup_fw(struct hci_uart *hu)
334 {
335 	struct nokia_bt_dev *btdev = hu->priv;
336 	struct device *dev = &btdev->serdev->dev;
337 	const char *fwname;
338 	const struct firmware *fw;
339 	const u8 *fw_ptr;
340 	size_t fw_size;
341 	int err;
342 
343 	dev_dbg(dev, "setup firmware");
344 
345 	if (btdev->man_id == NOKIA_ID_BCM2048) {
346 		fwname = FIRMWARE_BCM2048;
347 	} else if (btdev->man_id == NOKIA_ID_TI1271) {
348 		fwname = FIRMWARE_TI1271;
349 	} else {
350 		dev_err(dev, "Unsupported bluetooth device!");
351 		return -ENODEV;
352 	}
353 
354 	err = request_firmware(&fw, fwname, dev);
355 	if (err < 0) {
356 		dev_err(dev, "%s: Failed to load Nokia firmware file (%d)",
357 			hu->hdev->name, err);
358 		return err;
359 	}
360 
361 	fw_ptr = fw->data;
362 	fw_size = fw->size;
363 
364 	while (fw_size >= 4) {
365 		u16 pkt_size = get_unaligned_le16(fw_ptr);
366 		u8 pkt_type = fw_ptr[2];
367 		const struct hci_command_hdr *cmd;
368 		u16 opcode;
369 		struct sk_buff *skb;
370 
371 		switch (pkt_type) {
372 		case HCI_COMMAND_PKT:
373 			cmd = (struct hci_command_hdr *)(fw_ptr + 3);
374 			opcode = le16_to_cpu(cmd->opcode);
375 
376 			skb = __hci_cmd_sync(hu->hdev, opcode, cmd->plen,
377 					     fw_ptr + 3 + HCI_COMMAND_HDR_SIZE,
378 					     HCI_INIT_TIMEOUT);
379 			if (IS_ERR(skb)) {
380 				err = PTR_ERR(skb);
381 				dev_err(dev, "%s: FW command %04x failed (%d)",
382 				       hu->hdev->name, opcode, err);
383 				goto done;
384 			}
385 			kfree_skb(skb);
386 			break;
387 		case HCI_NOKIA_RADIO_PKT:
388 		case HCI_NOKIA_NEG_PKT:
389 		case HCI_NOKIA_ALIVE_PKT:
390 			break;
391 		}
392 
393 		fw_ptr += pkt_size + 2;
394 		fw_size -= pkt_size + 2;
395 	}
396 
397 done:
398 	release_firmware(fw);
399 	return err;
400 }
401 
402 static int nokia_setup(struct hci_uart *hu)
403 {
404 	struct nokia_bt_dev *btdev = hu->priv;
405 	struct device *dev = &btdev->serdev->dev;
406 	int err;
407 
408 	btdev->initialized = false;
409 
410 	nokia_flow_control(btdev->serdev, false);
411 
412 	pm_runtime_get_sync(dev);
413 
414 	if (btdev->tx_enabled) {
415 		gpiod_set_value_cansleep(btdev->wakeup_bt, 0);
416 		pm_runtime_put(&btdev->serdev->dev);
417 		btdev->tx_enabled = false;
418 	}
419 
420 	dev_dbg(dev, "protocol setup");
421 
422 	/* 0. reset connection */
423 	err = nokia_reset(hu);
424 	if (err < 0) {
425 		dev_err(dev, "Reset failed: %d", err);
426 		goto out;
427 	}
428 
429 	/* 1. negotiate speed etc */
430 	err = nokia_send_negotiation(hu);
431 	if (err < 0) {
432 		dev_err(dev, "Negotiation failed: %d", err);
433 		goto out;
434 	}
435 
436 	/* 2. verify correct setup using alive packet */
437 	err = nokia_send_alive_packet(hu);
438 	if (err < 0) {
439 		dev_err(dev, "Alive check failed: %d", err);
440 		goto out;
441 	}
442 
443 	/* 3. send firmware */
444 	err = nokia_setup_fw(hu);
445 	if (err < 0) {
446 		dev_err(dev, "Could not setup FW: %d", err);
447 		goto out;
448 	}
449 
450 	nokia_flow_control(btdev->serdev, false);
451 	serdev_device_set_baudrate(btdev->serdev, MAX_BAUD_RATE);
452 	nokia_flow_control(btdev->serdev, true);
453 
454 	if (btdev->man_id == NOKIA_ID_BCM2048) {
455 		hu->hdev->set_bdaddr = btbcm_set_bdaddr;
456 		set_bit(HCI_QUIRK_INVALID_BDADDR, &hu->hdev->quirks);
457 		dev_dbg(dev, "bcm2048 has invalid bluetooth address!");
458 	}
459 
460 	dev_dbg(dev, "protocol setup done!");
461 
462 	gpiod_set_value_cansleep(btdev->wakeup_bt, 0);
463 	pm_runtime_put(dev);
464 	btdev->tx_enabled = false;
465 	btdev->initialized = true;
466 
467 	return 0;
468 out:
469 	pm_runtime_put(dev);
470 
471 	return err;
472 }
473 
474 static int nokia_open(struct hci_uart *hu)
475 {
476 	struct device *dev = &hu->serdev->dev;
477 
478 	dev_dbg(dev, "protocol open");
479 
480 	serdev_device_open(hu->serdev);
481 
482 	pm_runtime_enable(dev);
483 
484 	return 0;
485 }
486 
487 static int nokia_flush(struct hci_uart *hu)
488 {
489 	struct nokia_bt_dev *btdev = hu->priv;
490 
491 	dev_dbg(&btdev->serdev->dev, "flush device");
492 
493 	skb_queue_purge(&btdev->txq);
494 
495 	return 0;
496 }
497 
498 static int nokia_close(struct hci_uart *hu)
499 {
500 	struct nokia_bt_dev *btdev = hu->priv;
501 	struct device *dev = &btdev->serdev->dev;
502 
503 	dev_dbg(dev, "close device");
504 
505 	btdev->initialized = false;
506 
507 	skb_queue_purge(&btdev->txq);
508 
509 	kfree_skb(btdev->rx_skb);
510 
511 	/* disable module */
512 	gpiod_set_value(btdev->reset, 1);
513 	gpiod_set_value(btdev->wakeup_bt, 0);
514 
515 	pm_runtime_disable(&btdev->serdev->dev);
516 	serdev_device_close(btdev->serdev);
517 
518 	return 0;
519 }
520 
521 /* Enqueue frame for transmittion (padding, crc, etc) */
522 static int nokia_enqueue(struct hci_uart *hu, struct sk_buff *skb)
523 {
524 	struct nokia_bt_dev *btdev = hu->priv;
525 	int err;
526 
527 	/* Prepend skb with frame type */
528 	memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);
529 
530 	/* Packets must be word aligned */
531 	if (skb->len % 2) {
532 		err = skb_pad(skb, 1);
533 		if (err)
534 			return err;
535 		*skb_put(skb, 1) = 0x00;
536 	}
537 
538 	skb_queue_tail(&btdev->txq, skb);
539 
540 	return 0;
541 }
542 
543 static int nokia_recv_negotiation_packet(struct hci_dev *hdev,
544 					 struct sk_buff *skb)
545 {
546 	struct hci_uart *hu = hci_get_drvdata(hdev);
547 	struct nokia_bt_dev *btdev = hu->priv;
548 	struct device *dev = &btdev->serdev->dev;
549 	struct hci_nokia_neg_hdr *hdr;
550 	struct hci_nokia_neg_evt *evt;
551 	int ret = 0;
552 
553 	hdr = (struct hci_nokia_neg_hdr *)skb->data;
554 	if (hdr->dlen != sizeof(*evt)) {
555 		btdev->init_error = -EIO;
556 		ret = -EIO;
557 		goto finish_neg;
558 	}
559 
560 	evt = (struct hci_nokia_neg_evt *)skb_pull(skb, sizeof(*hdr));
561 
562 	if (evt->ack != NOKIA_NEG_ACK) {
563 		dev_err(dev, "Negotiation received: wrong reply");
564 		btdev->init_error = -EINVAL;
565 		ret = -EINVAL;
566 		goto finish_neg;
567 	}
568 
569 	btdev->man_id = evt->man_id;
570 	btdev->ver_id = evt->ver_id;
571 
572 	dev_dbg(dev, "Negotiation received: baud=%u:clk=%u:manu=%u:vers=%u",
573 		evt->baud, evt->sys_clk, evt->man_id, evt->ver_id);
574 
575 finish_neg:
576 	complete(&btdev->init_completion);
577 	kfree_skb(skb);
578 	return ret;
579 }
580 
581 static int nokia_recv_alive_packet(struct hci_dev *hdev, struct sk_buff *skb)
582 {
583 	struct hci_uart *hu = hci_get_drvdata(hdev);
584 	struct nokia_bt_dev *btdev = hu->priv;
585 	struct device *dev = &btdev->serdev->dev;
586 	struct hci_nokia_alive_hdr *hdr;
587 	struct hci_nokia_alive_pkt *pkt;
588 	int ret = 0;
589 
590 	hdr = (struct hci_nokia_alive_hdr *)skb->data;
591 	if (hdr->dlen != sizeof(*pkt)) {
592 		dev_err(dev, "Corrupted alive message");
593 		btdev->init_error = -EIO;
594 		ret = -EIO;
595 		goto finish_alive;
596 	}
597 
598 	pkt = (struct hci_nokia_alive_pkt *)skb_pull(skb, sizeof(*hdr));
599 
600 	if (pkt->mid != NOKIA_ALIVE_RESP) {
601 		dev_err(dev, "Alive received: invalid response: 0x%02x!",
602 			pkt->mid);
603 		btdev->init_error = -EINVAL;
604 		ret = -EINVAL;
605 		goto finish_alive;
606 	}
607 
608 	dev_dbg(dev, "Alive received");
609 
610 finish_alive:
611 	complete(&btdev->init_completion);
612 	kfree_skb(skb);
613 	return ret;
614 }
615 
616 static int nokia_recv_radio(struct hci_dev *hdev, struct sk_buff *skb)
617 {
618 	/* Packets received on the dedicated radio channel are
619 	 * HCI events and so feed them back into the core.
620 	 */
621 	hci_skb_pkt_type(skb) = HCI_EVENT_PKT;
622 	return hci_recv_frame(hdev, skb);
623 }
624 
625 /* Recv data */
626 static const struct h4_recv_pkt nokia_recv_pkts[] = {
627 	{ H4_RECV_ACL,		.recv = hci_recv_frame },
628 	{ H4_RECV_SCO,		.recv = hci_recv_frame },
629 	{ H4_RECV_EVENT,	.recv = hci_recv_frame },
630 	{ NOKIA_RECV_ALIVE,	.recv = nokia_recv_alive_packet },
631 	{ NOKIA_RECV_NEG,	.recv = nokia_recv_negotiation_packet },
632 	{ NOKIA_RECV_RADIO,	.recv = nokia_recv_radio },
633 };
634 
635 static int nokia_recv(struct hci_uart *hu, const void *data, int count)
636 {
637 	struct nokia_bt_dev *btdev = hu->priv;
638 	struct device *dev = &btdev->serdev->dev;
639 	int err;
640 
641 	if (!test_bit(HCI_UART_REGISTERED, &hu->flags))
642 		return -EUNATCH;
643 
644 	btdev->rx_skb = h4_recv_buf(hu->hdev, btdev->rx_skb, data, count,
645 				  nokia_recv_pkts, ARRAY_SIZE(nokia_recv_pkts));
646 	if (IS_ERR(btdev->rx_skb)) {
647 		err = PTR_ERR(btdev->rx_skb);
648 		dev_err(dev, "Frame reassembly failed (%d)", err);
649 		btdev->rx_skb = NULL;
650 		return err;
651 	}
652 
653 	return count;
654 }
655 
656 static struct sk_buff *nokia_dequeue(struct hci_uart *hu)
657 {
658 	struct nokia_bt_dev *btdev = hu->priv;
659 	struct device *dev = &btdev->serdev->dev;
660 	struct sk_buff *result = skb_dequeue(&btdev->txq);
661 
662 	if (!btdev->initialized)
663 		return result;
664 
665 	if (btdev->tx_enabled == !!result)
666 		return result;
667 
668 	if (result) {
669 		pm_runtime_get_sync(dev);
670 		gpiod_set_value_cansleep(btdev->wakeup_bt, 1);
671 	} else {
672 		serdev_device_wait_until_sent(btdev->serdev, 0);
673 		gpiod_set_value_cansleep(btdev->wakeup_bt, 0);
674 		pm_runtime_put(dev);
675 	}
676 
677 	btdev->tx_enabled = !!result;
678 
679 	return result;
680 }
681 
682 static const struct hci_uart_proto nokia_proto = {
683 	.id		= HCI_UART_NOKIA,
684 	.name		= "Nokia",
685 	.open		= nokia_open,
686 	.close		= nokia_close,
687 	.recv		= nokia_recv,
688 	.enqueue	= nokia_enqueue,
689 	.dequeue	= nokia_dequeue,
690 	.flush		= nokia_flush,
691 	.setup		= nokia_setup,
692 	.manufacturer	= 1,
693 };
694 
695 static int nokia_bluetooth_serdev_probe(struct serdev_device *serdev)
696 {
697 	struct device *dev = &serdev->dev;
698 	struct nokia_bt_dev *btdev;
699 	struct clk *sysclk;
700 	int err = 0;
701 
702 	btdev = devm_kzalloc(dev, sizeof(*btdev), GFP_KERNEL);
703 	if (!btdev)
704 		return -ENOMEM;
705 
706 	btdev->hu.serdev = btdev->serdev = serdev;
707 	serdev_device_set_drvdata(serdev, btdev);
708 
709 	btdev->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
710 	if (IS_ERR(btdev->reset)) {
711 		err = PTR_ERR(btdev->reset);
712 		dev_err(dev, "could not get reset gpio: %d", err);
713 		return err;
714 	}
715 
716 	btdev->wakeup_host = devm_gpiod_get(dev, "host-wakeup", GPIOD_IN);
717 	if (IS_ERR(btdev->wakeup_host)) {
718 		err = PTR_ERR(btdev->wakeup_host);
719 		dev_err(dev, "could not get host wakeup gpio: %d", err);
720 		return err;
721 	}
722 
723 	btdev->wake_irq = gpiod_to_irq(btdev->wakeup_host);
724 
725 	err = devm_request_threaded_irq(dev, btdev->wake_irq, NULL,
726 		wakeup_handler,
727 		IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
728 		"wakeup", btdev);
729 	if (err) {
730 		dev_err(dev, "could request wakeup irq: %d", err);
731 		return err;
732 	}
733 
734 	btdev->wakeup_bt = devm_gpiod_get(dev, "bluetooth-wakeup",
735 					   GPIOD_OUT_LOW);
736 	if (IS_ERR(btdev->wakeup_bt)) {
737 		err = PTR_ERR(btdev->wakeup_bt);
738 		dev_err(dev, "could not get BT wakeup gpio: %d", err);
739 		return err;
740 	}
741 
742 	sysclk = devm_clk_get(dev, "sysclk");
743 	if (IS_ERR(sysclk)) {
744 		err = PTR_ERR(sysclk);
745 		dev_err(dev, "could not get sysclk: %d", err);
746 		return err;
747 	}
748 
749 	clk_prepare_enable(sysclk);
750 	btdev->sysclk_speed = clk_get_rate(sysclk);
751 	clk_disable_unprepare(sysclk);
752 
753 	skb_queue_head_init(&btdev->txq);
754 
755 	btdev->hu.priv = btdev;
756 	btdev->hu.alignment = 2; /* Nokia H4+ is word aligned */
757 
758 	err = hci_uart_register_device(&btdev->hu, &nokia_proto);
759 	if (err) {
760 		dev_err(dev, "could not register bluetooth uart: %d", err);
761 		return err;
762 	}
763 
764 	return 0;
765 }
766 
767 static void nokia_bluetooth_serdev_remove(struct serdev_device *serdev)
768 {
769 	struct nokia_bt_dev *btdev = serdev_device_get_drvdata(serdev);
770 	struct hci_uart *hu = &btdev->hu;
771 	struct hci_dev *hdev = hu->hdev;
772 
773 	cancel_work_sync(&hu->write_work);
774 
775 	hci_unregister_dev(hdev);
776 	hci_free_dev(hdev);
777 	hu->proto->close(hu);
778 
779 	pm_runtime_disable(&btdev->serdev->dev);
780 }
781 
782 static int nokia_bluetooth_runtime_suspend(struct device *dev)
783 {
784 	struct serdev_device *serdev = to_serdev_device(dev);
785 
786 	nokia_flow_control(serdev, false);
787 	return 0;
788 }
789 
790 static int nokia_bluetooth_runtime_resume(struct device *dev)
791 {
792 	struct serdev_device *serdev = to_serdev_device(dev);
793 
794 	nokia_flow_control(serdev, true);
795 	return 0;
796 }
797 
798 static const struct dev_pm_ops nokia_bluetooth_pm_ops = {
799 	SET_RUNTIME_PM_OPS(nokia_bluetooth_runtime_suspend,
800 			   nokia_bluetooth_runtime_resume,
801 			   NULL)
802 };
803 
804 #ifdef CONFIG_OF
805 static const struct of_device_id nokia_bluetooth_of_match[] = {
806 	{ .compatible = "nokia,h4p-bluetooth", },
807 	{},
808 };
809 MODULE_DEVICE_TABLE(of, nokia_bluetooth_of_match);
810 #endif
811 
812 static struct serdev_device_driver nokia_bluetooth_serdev_driver = {
813 	.probe = nokia_bluetooth_serdev_probe,
814 	.remove = nokia_bluetooth_serdev_remove,
815 	.driver = {
816 		.name = "nokia-bluetooth",
817 		.pm = &nokia_bluetooth_pm_ops,
818 		.of_match_table = of_match_ptr(nokia_bluetooth_of_match),
819 	},
820 };
821 
822 module_serdev_device_driver(nokia_bluetooth_serdev_driver);
823 
824 MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
825 MODULE_DESCRIPTION("Bluetooth HCI UART Nokia H4+ driver ver " VERSION);
826 MODULE_VERSION(VERSION);
827 MODULE_LICENSE("GPL");
828