xref: /linux/drivers/bluetooth/btmtkuart.c (revision c4101e55974cc7d835fbd2d8e01553a3f61e9e75)
1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2018 MediaTek Inc.
3 
4 /*
5  * Bluetooth support for MediaTek serial devices
6  *
7  * Author: Sean Wang <sean.wang@mediatek.com>
8  *
9  */
10 
11 #include <asm/unaligned.h>
12 #include <linux/atomic.h>
13 #include <linux/clk.h>
14 #include <linux/firmware.h>
15 #include <linux/gpio/consumer.h>
16 #include <linux/iopoll.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/of.h>
20 #include <linux/pinctrl/consumer.h>
21 #include <linux/pm_runtime.h>
22 #include <linux/regulator/consumer.h>
23 #include <linux/serdev.h>
24 #include <linux/skbuff.h>
25 
26 #include <net/bluetooth/bluetooth.h>
27 #include <net/bluetooth/hci_core.h>
28 
29 #include "h4_recv.h"
30 #include "btmtk.h"
31 
32 #define VERSION "0.2"
33 
34 #define MTK_STP_TLR_SIZE	2
35 
36 #define BTMTKUART_TX_STATE_ACTIVE	1
37 #define BTMTKUART_TX_STATE_WAKEUP	2
38 #define BTMTKUART_TX_WAIT_VND_EVT	3
39 #define BTMTKUART_REQUIRED_WAKEUP	4
40 
41 #define BTMTKUART_FLAG_STANDALONE_HW	 BIT(0)
42 
43 struct mtk_stp_hdr {
44 	u8	prefix;
45 	__be16	dlen;
46 	u8	cs;
47 } __packed;
48 
49 struct btmtkuart_data {
50 	unsigned int flags;
51 	const char *fwname;
52 };
53 
54 struct btmtkuart_dev {
55 	struct hci_dev *hdev;
56 	struct serdev_device *serdev;
57 
58 	struct clk *clk;
59 	struct clk *osc;
60 	struct regulator *vcc;
61 	struct gpio_desc *reset;
62 	struct gpio_desc *boot;
63 	struct pinctrl *pinctrl;
64 	struct pinctrl_state *pins_runtime;
65 	struct pinctrl_state *pins_boot;
66 	speed_t	desired_speed;
67 	speed_t	curr_speed;
68 
69 	struct work_struct tx_work;
70 	unsigned long tx_state;
71 	struct sk_buff_head txq;
72 
73 	struct sk_buff *rx_skb;
74 	struct sk_buff *evt_skb;
75 
76 	u8	stp_pad[6];
77 	u8	stp_cursor;
78 	u16	stp_dlen;
79 
80 	const struct btmtkuart_data *data;
81 };
82 
83 #define btmtkuart_is_standalone(bdev)	\
84 	((bdev)->data->flags & BTMTKUART_FLAG_STANDALONE_HW)
85 #define btmtkuart_is_builtin_soc(bdev)	\
86 	!((bdev)->data->flags & BTMTKUART_FLAG_STANDALONE_HW)
87 
88 static int mtk_hci_wmt_sync(struct hci_dev *hdev,
89 			    struct btmtk_hci_wmt_params *wmt_params)
90 {
91 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
92 	struct btmtk_hci_wmt_evt_funcc *wmt_evt_funcc;
93 	u32 hlen, status = BTMTK_WMT_INVALID;
94 	struct btmtk_hci_wmt_evt *wmt_evt;
95 	struct btmtk_hci_wmt_cmd *wc;
96 	struct btmtk_wmt_hdr *hdr;
97 	int err;
98 
99 	/* Send the WMT command and wait until the WMT event returns */
100 	hlen = sizeof(*hdr) + wmt_params->dlen;
101 	if (hlen > 255) {
102 		err = -EINVAL;
103 		goto err_free_skb;
104 	}
105 
106 	wc = kzalloc(hlen, GFP_KERNEL);
107 	if (!wc) {
108 		err = -ENOMEM;
109 		goto err_free_skb;
110 	}
111 
112 	hdr = &wc->hdr;
113 	hdr->dir = 1;
114 	hdr->op = wmt_params->op;
115 	hdr->dlen = cpu_to_le16(wmt_params->dlen + 1);
116 	hdr->flag = wmt_params->flag;
117 	memcpy(wc->data, wmt_params->data, wmt_params->dlen);
118 
119 	set_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state);
120 
121 	err = __hci_cmd_send(hdev, 0xfc6f, hlen, wc);
122 	if (err < 0) {
123 		clear_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state);
124 		goto err_free_wc;
125 	}
126 
127 	/* The vendor specific WMT commands are all answered by a vendor
128 	 * specific event and will not have the Command Status or Command
129 	 * Complete as with usual HCI command flow control.
130 	 *
131 	 * After sending the command, wait for BTMTKUART_TX_WAIT_VND_EVT
132 	 * state to be cleared. The driver specific event receive routine
133 	 * will clear that state and with that indicate completion of the
134 	 * WMT command.
135 	 */
136 	err = wait_on_bit_timeout(&bdev->tx_state, BTMTKUART_TX_WAIT_VND_EVT,
137 				  TASK_INTERRUPTIBLE, HCI_INIT_TIMEOUT);
138 	if (err == -EINTR) {
139 		bt_dev_err(hdev, "Execution of wmt command interrupted");
140 		clear_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state);
141 		goto err_free_wc;
142 	}
143 
144 	if (err) {
145 		bt_dev_err(hdev, "Execution of wmt command timed out");
146 		clear_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state);
147 		err = -ETIMEDOUT;
148 		goto err_free_wc;
149 	}
150 
151 	/* Parse and handle the return WMT event */
152 	wmt_evt = (struct btmtk_hci_wmt_evt *)bdev->evt_skb->data;
153 	if (wmt_evt->whdr.op != hdr->op) {
154 		bt_dev_err(hdev, "Wrong op received %d expected %d",
155 			   wmt_evt->whdr.op, hdr->op);
156 		err = -EIO;
157 		goto err_free_wc;
158 	}
159 
160 	switch (wmt_evt->whdr.op) {
161 	case BTMTK_WMT_SEMAPHORE:
162 		if (wmt_evt->whdr.flag == 2)
163 			status = BTMTK_WMT_PATCH_UNDONE;
164 		else
165 			status = BTMTK_WMT_PATCH_DONE;
166 		break;
167 	case BTMTK_WMT_FUNC_CTRL:
168 		wmt_evt_funcc = (struct btmtk_hci_wmt_evt_funcc *)wmt_evt;
169 		if (be16_to_cpu(wmt_evt_funcc->status) == 0x404)
170 			status = BTMTK_WMT_ON_DONE;
171 		else if (be16_to_cpu(wmt_evt_funcc->status) == 0x420)
172 			status = BTMTK_WMT_ON_PROGRESS;
173 		else
174 			status = BTMTK_WMT_ON_UNDONE;
175 		break;
176 	}
177 
178 	if (wmt_params->status)
179 		*wmt_params->status = status;
180 
181 err_free_wc:
182 	kfree(wc);
183 err_free_skb:
184 	kfree_skb(bdev->evt_skb);
185 	bdev->evt_skb = NULL;
186 
187 	return err;
188 }
189 
190 static int btmtkuart_recv_event(struct hci_dev *hdev, struct sk_buff *skb)
191 {
192 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
193 	struct hci_event_hdr *hdr = (void *)skb->data;
194 	int err;
195 
196 	/* When someone waits for the WMT event, the skb is being cloned
197 	 * and being processed the events from there then.
198 	 */
199 	if (test_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state)) {
200 		bdev->evt_skb = skb_clone(skb, GFP_KERNEL);
201 		if (!bdev->evt_skb) {
202 			err = -ENOMEM;
203 			goto err_out;
204 		}
205 	}
206 
207 	err = hci_recv_frame(hdev, skb);
208 	if (err < 0)
209 		goto err_free_skb;
210 
211 	if (hdr->evt == HCI_EV_WMT) {
212 		if (test_and_clear_bit(BTMTKUART_TX_WAIT_VND_EVT,
213 				       &bdev->tx_state)) {
214 			/* Barrier to sync with other CPUs */
215 			smp_mb__after_atomic();
216 			wake_up_bit(&bdev->tx_state, BTMTKUART_TX_WAIT_VND_EVT);
217 		}
218 	}
219 
220 	return 0;
221 
222 err_free_skb:
223 	kfree_skb(bdev->evt_skb);
224 	bdev->evt_skb = NULL;
225 
226 err_out:
227 	return err;
228 }
229 
230 static const struct h4_recv_pkt mtk_recv_pkts[] = {
231 	{ H4_RECV_ACL,      .recv = hci_recv_frame },
232 	{ H4_RECV_SCO,      .recv = hci_recv_frame },
233 	{ H4_RECV_EVENT,    .recv = btmtkuart_recv_event },
234 };
235 
236 static void btmtkuart_tx_work(struct work_struct *work)
237 {
238 	struct btmtkuart_dev *bdev = container_of(work, struct btmtkuart_dev,
239 						   tx_work);
240 	struct serdev_device *serdev = bdev->serdev;
241 	struct hci_dev *hdev = bdev->hdev;
242 
243 	while (1) {
244 		clear_bit(BTMTKUART_TX_STATE_WAKEUP, &bdev->tx_state);
245 
246 		while (1) {
247 			struct sk_buff *skb = skb_dequeue(&bdev->txq);
248 			int len;
249 
250 			if (!skb)
251 				break;
252 
253 			len = serdev_device_write_buf(serdev, skb->data,
254 						      skb->len);
255 			hdev->stat.byte_tx += len;
256 
257 			skb_pull(skb, len);
258 			if (skb->len > 0) {
259 				skb_queue_head(&bdev->txq, skb);
260 				break;
261 			}
262 
263 			switch (hci_skb_pkt_type(skb)) {
264 			case HCI_COMMAND_PKT:
265 				hdev->stat.cmd_tx++;
266 				break;
267 			case HCI_ACLDATA_PKT:
268 				hdev->stat.acl_tx++;
269 				break;
270 			case HCI_SCODATA_PKT:
271 				hdev->stat.sco_tx++;
272 				break;
273 			}
274 
275 			kfree_skb(skb);
276 		}
277 
278 		if (!test_bit(BTMTKUART_TX_STATE_WAKEUP, &bdev->tx_state))
279 			break;
280 	}
281 
282 	clear_bit(BTMTKUART_TX_STATE_ACTIVE, &bdev->tx_state);
283 }
284 
285 static void btmtkuart_tx_wakeup(struct btmtkuart_dev *bdev)
286 {
287 	if (test_and_set_bit(BTMTKUART_TX_STATE_ACTIVE, &bdev->tx_state))
288 		set_bit(BTMTKUART_TX_STATE_WAKEUP, &bdev->tx_state);
289 
290 	schedule_work(&bdev->tx_work);
291 }
292 
293 static const unsigned char *
294 mtk_stp_split(struct btmtkuart_dev *bdev, const unsigned char *data, int count,
295 	      int *sz_h4)
296 {
297 	struct mtk_stp_hdr *shdr;
298 
299 	/* The cursor is reset when all the data of STP is consumed out */
300 	if (!bdev->stp_dlen && bdev->stp_cursor >= 6)
301 		bdev->stp_cursor = 0;
302 
303 	/* Filling pad until all STP info is obtained */
304 	while (bdev->stp_cursor < 6 && count > 0) {
305 		bdev->stp_pad[bdev->stp_cursor] = *data;
306 		bdev->stp_cursor++;
307 		data++;
308 		count--;
309 	}
310 
311 	/* Retrieve STP info and have a sanity check */
312 	if (!bdev->stp_dlen && bdev->stp_cursor >= 6) {
313 		shdr = (struct mtk_stp_hdr *)&bdev->stp_pad[2];
314 		bdev->stp_dlen = be16_to_cpu(shdr->dlen) & 0x0fff;
315 
316 		/* Resync STP when unexpected data is being read */
317 		if (shdr->prefix != 0x80 || bdev->stp_dlen > 2048) {
318 			bt_dev_err(bdev->hdev, "stp format unexpect (%d, %d)",
319 				   shdr->prefix, bdev->stp_dlen);
320 			bdev->stp_cursor = 2;
321 			bdev->stp_dlen = 0;
322 		}
323 	}
324 
325 	/* Directly quit when there's no data found for H4 can process */
326 	if (count <= 0)
327 		return NULL;
328 
329 	/* Tranlate to how much the size of data H4 can handle so far */
330 	*sz_h4 = min_t(int, count, bdev->stp_dlen);
331 
332 	/* Update the remaining size of STP packet */
333 	bdev->stp_dlen -= *sz_h4;
334 
335 	/* Data points to STP payload which can be handled by H4 */
336 	return data;
337 }
338 
339 static void btmtkuart_recv(struct hci_dev *hdev, const u8 *data, size_t count)
340 {
341 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
342 	const unsigned char *p_left = data, *p_h4;
343 	int sz_left = count, sz_h4, adv;
344 	int err;
345 
346 	while (sz_left > 0) {
347 		/*  The serial data received from MT7622 BT controller is
348 		 *  at all time padded around with the STP header and tailer.
349 		 *
350 		 *  A full STP packet is looking like
351 		 *   -----------------------------------
352 		 *  | STP header  |  H:4   | STP tailer |
353 		 *   -----------------------------------
354 		 *  but it doesn't guarantee to contain a full H:4 packet which
355 		 *  means that it's possible for multiple STP packets forms a
356 		 *  full H:4 packet that means extra STP header + length doesn't
357 		 *  indicate a full H:4 frame, things can fragment. Whose length
358 		 *  recorded in STP header just shows up the most length the
359 		 *  H:4 engine can handle currently.
360 		 */
361 
362 		p_h4 = mtk_stp_split(bdev, p_left, sz_left, &sz_h4);
363 		if (!p_h4)
364 			break;
365 
366 		adv = p_h4 - p_left;
367 		sz_left -= adv;
368 		p_left += adv;
369 
370 		bdev->rx_skb = h4_recv_buf(bdev->hdev, bdev->rx_skb, p_h4,
371 					   sz_h4, mtk_recv_pkts,
372 					   ARRAY_SIZE(mtk_recv_pkts));
373 		if (IS_ERR(bdev->rx_skb)) {
374 			err = PTR_ERR(bdev->rx_skb);
375 			bt_dev_err(bdev->hdev,
376 				   "Frame reassembly failed (%d)", err);
377 			bdev->rx_skb = NULL;
378 			return;
379 		}
380 
381 		sz_left -= sz_h4;
382 		p_left += sz_h4;
383 	}
384 }
385 
386 static int btmtkuart_receive_buf(struct serdev_device *serdev, const u8 *data,
387 				 size_t count)
388 {
389 	struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev);
390 
391 	btmtkuart_recv(bdev->hdev, data, count);
392 
393 	bdev->hdev->stat.byte_rx += count;
394 
395 	return count;
396 }
397 
398 static void btmtkuart_write_wakeup(struct serdev_device *serdev)
399 {
400 	struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev);
401 
402 	btmtkuart_tx_wakeup(bdev);
403 }
404 
405 static const struct serdev_device_ops btmtkuart_client_ops = {
406 	.receive_buf = btmtkuart_receive_buf,
407 	.write_wakeup = btmtkuart_write_wakeup,
408 };
409 
410 static int btmtkuart_open(struct hci_dev *hdev)
411 {
412 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
413 	struct device *dev;
414 	int err;
415 
416 	err = serdev_device_open(bdev->serdev);
417 	if (err) {
418 		bt_dev_err(hdev, "Unable to open UART device %s",
419 			   dev_name(&bdev->serdev->dev));
420 		goto err_open;
421 	}
422 
423 	if (btmtkuart_is_standalone(bdev)) {
424 		if (bdev->curr_speed != bdev->desired_speed)
425 			err = serdev_device_set_baudrate(bdev->serdev,
426 							 115200);
427 		else
428 			err = serdev_device_set_baudrate(bdev->serdev,
429 							 bdev->desired_speed);
430 
431 		if (err < 0) {
432 			bt_dev_err(hdev, "Unable to set baudrate UART device %s",
433 				   dev_name(&bdev->serdev->dev));
434 			goto  err_serdev_close;
435 		}
436 
437 		serdev_device_set_flow_control(bdev->serdev, false);
438 	}
439 
440 	bdev->stp_cursor = 2;
441 	bdev->stp_dlen = 0;
442 
443 	dev = &bdev->serdev->dev;
444 
445 	/* Enable the power domain and clock the device requires */
446 	pm_runtime_enable(dev);
447 	err = pm_runtime_resume_and_get(dev);
448 	if (err < 0)
449 		goto err_disable_rpm;
450 
451 	err = clk_prepare_enable(bdev->clk);
452 	if (err < 0)
453 		goto err_put_rpm;
454 
455 	return 0;
456 
457 err_put_rpm:
458 	pm_runtime_put_sync(dev);
459 err_disable_rpm:
460 	pm_runtime_disable(dev);
461 err_serdev_close:
462 	serdev_device_close(bdev->serdev);
463 err_open:
464 	return err;
465 }
466 
467 static int btmtkuart_close(struct hci_dev *hdev)
468 {
469 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
470 	struct device *dev = &bdev->serdev->dev;
471 
472 	/* Shutdown the clock and power domain the device requires */
473 	clk_disable_unprepare(bdev->clk);
474 	pm_runtime_put_sync(dev);
475 	pm_runtime_disable(dev);
476 
477 	serdev_device_close(bdev->serdev);
478 
479 	return 0;
480 }
481 
482 static int btmtkuart_flush(struct hci_dev *hdev)
483 {
484 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
485 
486 	/* Flush any pending characters */
487 	serdev_device_write_flush(bdev->serdev);
488 	skb_queue_purge(&bdev->txq);
489 
490 	cancel_work_sync(&bdev->tx_work);
491 
492 	kfree_skb(bdev->rx_skb);
493 	bdev->rx_skb = NULL;
494 
495 	bdev->stp_cursor = 2;
496 	bdev->stp_dlen = 0;
497 
498 	return 0;
499 }
500 
501 static int btmtkuart_func_query(struct hci_dev *hdev)
502 {
503 	struct btmtk_hci_wmt_params wmt_params;
504 	int status, err;
505 	u8 param = 0;
506 
507 	/* Query whether the function is enabled */
508 	wmt_params.op = BTMTK_WMT_FUNC_CTRL;
509 	wmt_params.flag = 4;
510 	wmt_params.dlen = sizeof(param);
511 	wmt_params.data = &param;
512 	wmt_params.status = &status;
513 
514 	err = mtk_hci_wmt_sync(hdev, &wmt_params);
515 	if (err < 0) {
516 		bt_dev_err(hdev, "Failed to query function status (%d)", err);
517 		return err;
518 	}
519 
520 	return status;
521 }
522 
523 static int btmtkuart_change_baudrate(struct hci_dev *hdev)
524 {
525 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
526 	struct btmtk_hci_wmt_params wmt_params;
527 	__le32 baudrate;
528 	u8 param;
529 	int err;
530 
531 	/* Indicate the device to enter the probe state the host is
532 	 * ready to change a new baudrate.
533 	 */
534 	baudrate = cpu_to_le32(bdev->desired_speed);
535 	wmt_params.op = BTMTK_WMT_HIF;
536 	wmt_params.flag = 1;
537 	wmt_params.dlen = 4;
538 	wmt_params.data = &baudrate;
539 	wmt_params.status = NULL;
540 
541 	err = mtk_hci_wmt_sync(hdev, &wmt_params);
542 	if (err < 0) {
543 		bt_dev_err(hdev, "Failed to device baudrate (%d)", err);
544 		return err;
545 	}
546 
547 	err = serdev_device_set_baudrate(bdev->serdev,
548 					 bdev->desired_speed);
549 	if (err < 0) {
550 		bt_dev_err(hdev, "Failed to set up host baudrate (%d)",
551 			   err);
552 		return err;
553 	}
554 
555 	serdev_device_set_flow_control(bdev->serdev, false);
556 
557 	/* Send a dummy byte 0xff to activate the new baudrate */
558 	param = 0xff;
559 	err = serdev_device_write_buf(bdev->serdev, &param, sizeof(param));
560 	if (err < 0 || err < sizeof(param))
561 		return err;
562 
563 	serdev_device_wait_until_sent(bdev->serdev, 0);
564 
565 	/* Wait some time for the device changing baudrate done */
566 	usleep_range(20000, 22000);
567 
568 	/* Test the new baudrate */
569 	wmt_params.op = BTMTK_WMT_TEST;
570 	wmt_params.flag = 7;
571 	wmt_params.dlen = 0;
572 	wmt_params.data = NULL;
573 	wmt_params.status = NULL;
574 
575 	err = mtk_hci_wmt_sync(hdev, &wmt_params);
576 	if (err < 0) {
577 		bt_dev_err(hdev, "Failed to test new baudrate (%d)",
578 			   err);
579 		return err;
580 	}
581 
582 	bdev->curr_speed = bdev->desired_speed;
583 
584 	return 0;
585 }
586 
587 static int btmtkuart_setup(struct hci_dev *hdev)
588 {
589 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
590 	struct btmtk_hci_wmt_params wmt_params;
591 	ktime_t calltime, delta, rettime;
592 	struct btmtk_tci_sleep tci_sleep;
593 	unsigned long long duration;
594 	struct sk_buff *skb;
595 	int err, status;
596 	u8 param = 0x1;
597 
598 	calltime = ktime_get();
599 
600 	/* Wakeup MCUSYS is required for certain devices before we start to
601 	 * do any setups.
602 	 */
603 	if (test_bit(BTMTKUART_REQUIRED_WAKEUP, &bdev->tx_state)) {
604 		wmt_params.op = BTMTK_WMT_WAKEUP;
605 		wmt_params.flag = 3;
606 		wmt_params.dlen = 0;
607 		wmt_params.data = NULL;
608 		wmt_params.status = NULL;
609 
610 		err = mtk_hci_wmt_sync(hdev, &wmt_params);
611 		if (err < 0) {
612 			bt_dev_err(hdev, "Failed to wakeup the chip (%d)", err);
613 			return err;
614 		}
615 
616 		clear_bit(BTMTKUART_REQUIRED_WAKEUP, &bdev->tx_state);
617 	}
618 
619 	if (btmtkuart_is_standalone(bdev))
620 		btmtkuart_change_baudrate(hdev);
621 
622 	/* Query whether the firmware is already download */
623 	wmt_params.op = BTMTK_WMT_SEMAPHORE;
624 	wmt_params.flag = 1;
625 	wmt_params.dlen = 0;
626 	wmt_params.data = NULL;
627 	wmt_params.status = &status;
628 
629 	err = mtk_hci_wmt_sync(hdev, &wmt_params);
630 	if (err < 0) {
631 		bt_dev_err(hdev, "Failed to query firmware status (%d)", err);
632 		return err;
633 	}
634 
635 	if (status == BTMTK_WMT_PATCH_DONE) {
636 		bt_dev_info(hdev, "Firmware already downloaded");
637 		goto ignore_setup_fw;
638 	}
639 
640 	/* Setup a firmware which the device definitely requires */
641 	err = btmtk_setup_firmware(hdev, bdev->data->fwname, mtk_hci_wmt_sync);
642 	if (err < 0)
643 		return err;
644 
645 ignore_setup_fw:
646 	/* Query whether the device is already enabled */
647 	err = readx_poll_timeout(btmtkuart_func_query, hdev, status,
648 				 status < 0 || status != BTMTK_WMT_ON_PROGRESS,
649 				 2000, 5000000);
650 	/* -ETIMEDOUT happens */
651 	if (err < 0)
652 		return err;
653 
654 	/* The other errors happen in btusb_mtk_func_query */
655 	if (status < 0)
656 		return status;
657 
658 	if (status == BTMTK_WMT_ON_DONE) {
659 		bt_dev_info(hdev, "function already on");
660 		goto ignore_func_on;
661 	}
662 
663 	/* Enable Bluetooth protocol */
664 	wmt_params.op = BTMTK_WMT_FUNC_CTRL;
665 	wmt_params.flag = 0;
666 	wmt_params.dlen = sizeof(param);
667 	wmt_params.data = &param;
668 	wmt_params.status = NULL;
669 
670 	err = mtk_hci_wmt_sync(hdev, &wmt_params);
671 	if (err < 0) {
672 		bt_dev_err(hdev, "Failed to send wmt func ctrl (%d)", err);
673 		return err;
674 	}
675 
676 ignore_func_on:
677 	/* Apply the low power environment setup */
678 	tci_sleep.mode = 0x5;
679 	tci_sleep.duration = cpu_to_le16(0x640);
680 	tci_sleep.host_duration = cpu_to_le16(0x640);
681 	tci_sleep.host_wakeup_pin = 0;
682 	tci_sleep.time_compensation = 0;
683 
684 	skb = __hci_cmd_sync(hdev, 0xfc7a, sizeof(tci_sleep), &tci_sleep,
685 			     HCI_INIT_TIMEOUT);
686 	if (IS_ERR(skb)) {
687 		err = PTR_ERR(skb);
688 		bt_dev_err(hdev, "Failed to apply low power setting (%d)", err);
689 		return err;
690 	}
691 	kfree_skb(skb);
692 
693 	rettime = ktime_get();
694 	delta = ktime_sub(rettime, calltime);
695 	duration = (unsigned long long)ktime_to_ns(delta) >> 10;
696 
697 	bt_dev_info(hdev, "Device setup in %llu usecs", duration);
698 
699 	return 0;
700 }
701 
702 static int btmtkuart_shutdown(struct hci_dev *hdev)
703 {
704 	struct btmtk_hci_wmt_params wmt_params;
705 	u8 param = 0x0;
706 	int err;
707 
708 	/* Disable the device */
709 	wmt_params.op = BTMTK_WMT_FUNC_CTRL;
710 	wmt_params.flag = 0;
711 	wmt_params.dlen = sizeof(param);
712 	wmt_params.data = &param;
713 	wmt_params.status = NULL;
714 
715 	err = mtk_hci_wmt_sync(hdev, &wmt_params);
716 	if (err < 0) {
717 		bt_dev_err(hdev, "Failed to send wmt func ctrl (%d)", err);
718 		return err;
719 	}
720 
721 	return 0;
722 }
723 
724 static int btmtkuart_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
725 {
726 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
727 	struct mtk_stp_hdr *shdr;
728 	int err, dlen, type = 0;
729 
730 	/* Prepend skb with frame type */
731 	memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);
732 
733 	/* Make sure that there is enough rooms for STP header and trailer */
734 	if (unlikely(skb_headroom(skb) < sizeof(*shdr)) ||
735 	    (skb_tailroom(skb) < MTK_STP_TLR_SIZE)) {
736 		err = pskb_expand_head(skb, sizeof(*shdr), MTK_STP_TLR_SIZE,
737 				       GFP_ATOMIC);
738 		if (err < 0)
739 			return err;
740 	}
741 
742 	/* Add the STP header */
743 	dlen = skb->len;
744 	shdr = skb_push(skb, sizeof(*shdr));
745 	shdr->prefix = 0x80;
746 	shdr->dlen = cpu_to_be16((dlen & 0x0fff) | (type << 12));
747 	shdr->cs = 0;		/* MT7622 doesn't care about checksum value */
748 
749 	/* Add the STP trailer */
750 	skb_put_zero(skb, MTK_STP_TLR_SIZE);
751 
752 	skb_queue_tail(&bdev->txq, skb);
753 
754 	btmtkuart_tx_wakeup(bdev);
755 	return 0;
756 }
757 
758 static int btmtkuart_parse_dt(struct serdev_device *serdev)
759 {
760 	struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev);
761 	struct device_node *node = serdev->dev.of_node;
762 	u32 speed = 921600;
763 	int err;
764 
765 	if (btmtkuart_is_standalone(bdev)) {
766 		of_property_read_u32(node, "current-speed", &speed);
767 
768 		bdev->desired_speed = speed;
769 
770 		bdev->vcc = devm_regulator_get(&serdev->dev, "vcc");
771 		if (IS_ERR(bdev->vcc)) {
772 			err = PTR_ERR(bdev->vcc);
773 			return err;
774 		}
775 
776 		bdev->osc = devm_clk_get_optional(&serdev->dev, "osc");
777 		if (IS_ERR(bdev->osc)) {
778 			err = PTR_ERR(bdev->osc);
779 			return err;
780 		}
781 
782 		bdev->boot = devm_gpiod_get_optional(&serdev->dev, "boot",
783 						     GPIOD_OUT_LOW);
784 		if (IS_ERR(bdev->boot)) {
785 			err = PTR_ERR(bdev->boot);
786 			return err;
787 		}
788 
789 		bdev->pinctrl = devm_pinctrl_get(&serdev->dev);
790 		if (IS_ERR(bdev->pinctrl)) {
791 			err = PTR_ERR(bdev->pinctrl);
792 			return err;
793 		}
794 
795 		bdev->pins_boot = pinctrl_lookup_state(bdev->pinctrl,
796 						       "default");
797 		if (IS_ERR(bdev->pins_boot) && !bdev->boot) {
798 			err = PTR_ERR(bdev->pins_boot);
799 			dev_err(&serdev->dev,
800 				"Should assign RXD to LOW at boot stage\n");
801 			return err;
802 		}
803 
804 		bdev->pins_runtime = pinctrl_lookup_state(bdev->pinctrl,
805 							  "runtime");
806 		if (IS_ERR(bdev->pins_runtime)) {
807 			err = PTR_ERR(bdev->pins_runtime);
808 			return err;
809 		}
810 
811 		bdev->reset = devm_gpiod_get_optional(&serdev->dev, "reset",
812 						      GPIOD_OUT_LOW);
813 		if (IS_ERR(bdev->reset)) {
814 			err = PTR_ERR(bdev->reset);
815 			return err;
816 		}
817 	} else if (btmtkuart_is_builtin_soc(bdev)) {
818 		bdev->clk = devm_clk_get(&serdev->dev, "ref");
819 		if (IS_ERR(bdev->clk))
820 			return PTR_ERR(bdev->clk);
821 	}
822 
823 	return 0;
824 }
825 
826 static int btmtkuart_probe(struct serdev_device *serdev)
827 {
828 	struct btmtkuart_dev *bdev;
829 	struct hci_dev *hdev;
830 	int err;
831 
832 	bdev = devm_kzalloc(&serdev->dev, sizeof(*bdev), GFP_KERNEL);
833 	if (!bdev)
834 		return -ENOMEM;
835 
836 	bdev->data = of_device_get_match_data(&serdev->dev);
837 	if (!bdev->data)
838 		return -ENODEV;
839 
840 	bdev->serdev = serdev;
841 	serdev_device_set_drvdata(serdev, bdev);
842 
843 	serdev_device_set_client_ops(serdev, &btmtkuart_client_ops);
844 
845 	err = btmtkuart_parse_dt(serdev);
846 	if (err < 0)
847 		return err;
848 
849 	INIT_WORK(&bdev->tx_work, btmtkuart_tx_work);
850 	skb_queue_head_init(&bdev->txq);
851 
852 	/* Initialize and register HCI device */
853 	hdev = hci_alloc_dev();
854 	if (!hdev) {
855 		dev_err(&serdev->dev, "Can't allocate HCI device\n");
856 		return -ENOMEM;
857 	}
858 
859 	bdev->hdev = hdev;
860 
861 	hdev->bus = HCI_UART;
862 	hci_set_drvdata(hdev, bdev);
863 
864 	hdev->open     = btmtkuart_open;
865 	hdev->close    = btmtkuart_close;
866 	hdev->flush    = btmtkuart_flush;
867 	hdev->setup    = btmtkuart_setup;
868 	hdev->shutdown = btmtkuart_shutdown;
869 	hdev->send     = btmtkuart_send_frame;
870 	hdev->set_bdaddr = btmtk_set_bdaddr;
871 	SET_HCIDEV_DEV(hdev, &serdev->dev);
872 
873 	hdev->manufacturer = 70;
874 	set_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks);
875 
876 	if (btmtkuart_is_standalone(bdev)) {
877 		err = clk_prepare_enable(bdev->osc);
878 		if (err < 0)
879 			goto err_hci_free_dev;
880 
881 		if (bdev->boot) {
882 			gpiod_set_value_cansleep(bdev->boot, 1);
883 		} else {
884 			/* Switch to the specific pin state for the booting
885 			 * requires.
886 			 */
887 			pinctrl_select_state(bdev->pinctrl, bdev->pins_boot);
888 		}
889 
890 		/* Power on */
891 		err = regulator_enable(bdev->vcc);
892 		if (err < 0)
893 			goto err_clk_disable_unprepare;
894 
895 		/* Reset if the reset-gpios is available otherwise the board
896 		 * -level design should be guaranteed.
897 		 */
898 		if (bdev->reset) {
899 			gpiod_set_value_cansleep(bdev->reset, 1);
900 			usleep_range(1000, 2000);
901 			gpiod_set_value_cansleep(bdev->reset, 0);
902 		}
903 
904 		/* Wait some time until device got ready and switch to the pin
905 		 * mode the device requires for UART transfers.
906 		 */
907 		msleep(50);
908 
909 		if (bdev->boot)
910 			devm_gpiod_put(&serdev->dev, bdev->boot);
911 
912 		pinctrl_select_state(bdev->pinctrl, bdev->pins_runtime);
913 
914 		/* A standalone device doesn't depends on power domain on SoC,
915 		 * so mark it as no callbacks.
916 		 */
917 		pm_runtime_no_callbacks(&serdev->dev);
918 
919 		set_bit(BTMTKUART_REQUIRED_WAKEUP, &bdev->tx_state);
920 	}
921 
922 	err = hci_register_dev(hdev);
923 	if (err < 0) {
924 		dev_err(&serdev->dev, "Can't register HCI device\n");
925 		goto err_regulator_disable;
926 	}
927 
928 	return 0;
929 
930 err_regulator_disable:
931 	if (btmtkuart_is_standalone(bdev))
932 		regulator_disable(bdev->vcc);
933 err_clk_disable_unprepare:
934 	if (btmtkuart_is_standalone(bdev))
935 		clk_disable_unprepare(bdev->osc);
936 err_hci_free_dev:
937 	hci_free_dev(hdev);
938 
939 	return err;
940 }
941 
942 static void btmtkuart_remove(struct serdev_device *serdev)
943 {
944 	struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev);
945 	struct hci_dev *hdev = bdev->hdev;
946 
947 	if (btmtkuart_is_standalone(bdev)) {
948 		regulator_disable(bdev->vcc);
949 		clk_disable_unprepare(bdev->osc);
950 	}
951 
952 	hci_unregister_dev(hdev);
953 	hci_free_dev(hdev);
954 }
955 
956 static const struct btmtkuart_data mt7622_data __maybe_unused = {
957 	.fwname = FIRMWARE_MT7622,
958 };
959 
960 static const struct btmtkuart_data mt7663_data __maybe_unused = {
961 	.flags = BTMTKUART_FLAG_STANDALONE_HW,
962 	.fwname = FIRMWARE_MT7663,
963 };
964 
965 static const struct btmtkuart_data mt7668_data __maybe_unused = {
966 	.flags = BTMTKUART_FLAG_STANDALONE_HW,
967 	.fwname = FIRMWARE_MT7668,
968 };
969 
970 #ifdef CONFIG_OF
971 static const struct of_device_id mtk_of_match_table[] = {
972 	{ .compatible = "mediatek,mt7622-bluetooth", .data = &mt7622_data},
973 	{ .compatible = "mediatek,mt7663u-bluetooth", .data = &mt7663_data},
974 	{ .compatible = "mediatek,mt7668u-bluetooth", .data = &mt7668_data},
975 	{ }
976 };
977 MODULE_DEVICE_TABLE(of, mtk_of_match_table);
978 #endif
979 
980 static struct serdev_device_driver btmtkuart_driver = {
981 	.probe = btmtkuart_probe,
982 	.remove = btmtkuart_remove,
983 	.driver = {
984 		.name = "btmtkuart",
985 		.of_match_table = of_match_ptr(mtk_of_match_table),
986 	},
987 };
988 
989 module_serdev_device_driver(btmtkuart_driver);
990 
991 MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
992 MODULE_DESCRIPTION("MediaTek Bluetooth Serial driver ver " VERSION);
993 MODULE_VERSION(VERSION);
994 MODULE_LICENSE("GPL");
995