xref: /openbmc/linux/drivers/bluetooth/btmtkuart.c (revision 63705da3)
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/of_device.h>
21 #include <linux/pinctrl/consumer.h>
22 #include <linux/pm_runtime.h>
23 #include <linux/regulator/consumer.h>
24 #include <linux/serdev.h>
25 #include <linux/skbuff.h>
26 
27 #include <net/bluetooth/bluetooth.h>
28 #include <net/bluetooth/hci_core.h>
29 
30 #include "h4_recv.h"
31 
32 #define VERSION "0.2"
33 
34 #define FIRMWARE_MT7622		"mediatek/mt7622pr2h.bin"
35 #define FIRMWARE_MT7663		"mediatek/mt7663pr2h.bin"
36 #define FIRMWARE_MT7668		"mediatek/mt7668pr2h.bin"
37 
38 #define MTK_STP_TLR_SIZE	2
39 
40 #define BTMTKUART_TX_STATE_ACTIVE	1
41 #define BTMTKUART_TX_STATE_WAKEUP	2
42 #define BTMTKUART_TX_WAIT_VND_EVT	3
43 #define BTMTKUART_REQUIRED_WAKEUP	4
44 
45 #define BTMTKUART_FLAG_STANDALONE_HW	 BIT(0)
46 
47 enum {
48 	MTK_WMT_PATCH_DWNLD = 0x1,
49 	MTK_WMT_TEST = 0x2,
50 	MTK_WMT_WAKEUP = 0x3,
51 	MTK_WMT_HIF = 0x4,
52 	MTK_WMT_FUNC_CTRL = 0x6,
53 	MTK_WMT_RST = 0x7,
54 	MTK_WMT_SEMAPHORE = 0x17,
55 };
56 
57 enum {
58 	BTMTK_WMT_INVALID,
59 	BTMTK_WMT_PATCH_UNDONE,
60 	BTMTK_WMT_PATCH_DONE,
61 	BTMTK_WMT_ON_UNDONE,
62 	BTMTK_WMT_ON_DONE,
63 	BTMTK_WMT_ON_PROGRESS,
64 };
65 
66 struct mtk_stp_hdr {
67 	u8	prefix;
68 	__be16	dlen;
69 	u8	cs;
70 } __packed;
71 
72 struct btmtkuart_data {
73 	unsigned int flags;
74 	const char *fwname;
75 };
76 
77 struct mtk_wmt_hdr {
78 	u8	dir;
79 	u8	op;
80 	__le16	dlen;
81 	u8	flag;
82 } __packed;
83 
84 struct mtk_hci_wmt_cmd {
85 	struct mtk_wmt_hdr hdr;
86 	u8 data[256];
87 } __packed;
88 
89 struct btmtk_hci_wmt_evt {
90 	struct hci_event_hdr hhdr;
91 	struct mtk_wmt_hdr whdr;
92 } __packed;
93 
94 struct btmtk_hci_wmt_evt_funcc {
95 	struct btmtk_hci_wmt_evt hwhdr;
96 	__be16 status;
97 } __packed;
98 
99 struct btmtk_tci_sleep {
100 	u8 mode;
101 	__le16 duration;
102 	__le16 host_duration;
103 	u8 host_wakeup_pin;
104 	u8 time_compensation;
105 } __packed;
106 
107 struct btmtk_hci_wmt_params {
108 	u8 op;
109 	u8 flag;
110 	u16 dlen;
111 	const void *data;
112 	u32 *status;
113 };
114 
115 struct btmtkuart_dev {
116 	struct hci_dev *hdev;
117 	struct serdev_device *serdev;
118 
119 	struct clk *clk;
120 	struct clk *osc;
121 	struct regulator *vcc;
122 	struct gpio_desc *reset;
123 	struct gpio_desc *boot;
124 	struct pinctrl *pinctrl;
125 	struct pinctrl_state *pins_runtime;
126 	struct pinctrl_state *pins_boot;
127 	speed_t	desired_speed;
128 	speed_t	curr_speed;
129 
130 	struct work_struct tx_work;
131 	unsigned long tx_state;
132 	struct sk_buff_head txq;
133 
134 	struct sk_buff *rx_skb;
135 	struct sk_buff *evt_skb;
136 
137 	u8	stp_pad[6];
138 	u8	stp_cursor;
139 	u16	stp_dlen;
140 
141 	const struct btmtkuart_data *data;
142 };
143 
144 #define btmtkuart_is_standalone(bdev)	\
145 	((bdev)->data->flags & BTMTKUART_FLAG_STANDALONE_HW)
146 #define btmtkuart_is_builtin_soc(bdev)	\
147 	!((bdev)->data->flags & BTMTKUART_FLAG_STANDALONE_HW)
148 
149 static int mtk_hci_wmt_sync(struct hci_dev *hdev,
150 			    struct btmtk_hci_wmt_params *wmt_params)
151 {
152 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
153 	struct btmtk_hci_wmt_evt_funcc *wmt_evt_funcc;
154 	u32 hlen, status = BTMTK_WMT_INVALID;
155 	struct btmtk_hci_wmt_evt *wmt_evt;
156 	struct mtk_hci_wmt_cmd wc;
157 	struct mtk_wmt_hdr *hdr;
158 	int err;
159 
160 	hlen = sizeof(*hdr) + wmt_params->dlen;
161 	if (hlen > 255) {
162 		err = -EINVAL;
163 		goto err_free_skb;
164 	}
165 
166 	hdr = (struct mtk_wmt_hdr *)&wc;
167 	hdr->dir = 1;
168 	hdr->op = wmt_params->op;
169 	hdr->dlen = cpu_to_le16(wmt_params->dlen + 1);
170 	hdr->flag = wmt_params->flag;
171 	memcpy(wc.data, wmt_params->data, wmt_params->dlen);
172 
173 	set_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state);
174 
175 	err = __hci_cmd_send(hdev, 0xfc6f, hlen, &wc);
176 	if (err < 0) {
177 		clear_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state);
178 		goto err_free_skb;
179 	}
180 
181 	/* The vendor specific WMT commands are all answered by a vendor
182 	 * specific event and will not have the Command Status or Command
183 	 * Complete as with usual HCI command flow control.
184 	 *
185 	 * After sending the command, wait for BTMTKUART_TX_WAIT_VND_EVT
186 	 * state to be cleared. The driver specific event receive routine
187 	 * will clear that state and with that indicate completion of the
188 	 * WMT command.
189 	 */
190 	err = wait_on_bit_timeout(&bdev->tx_state, BTMTKUART_TX_WAIT_VND_EVT,
191 				  TASK_INTERRUPTIBLE, HCI_INIT_TIMEOUT);
192 	if (err == -EINTR) {
193 		bt_dev_err(hdev, "Execution of wmt command interrupted");
194 		clear_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state);
195 		goto err_free_skb;
196 	}
197 
198 	if (err) {
199 		bt_dev_err(hdev, "Execution of wmt command timed out");
200 		clear_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state);
201 		err = -ETIMEDOUT;
202 		goto err_free_skb;
203 	}
204 
205 	/* Parse and handle the return WMT event */
206 	wmt_evt = (struct btmtk_hci_wmt_evt *)bdev->evt_skb->data;
207 	if (wmt_evt->whdr.op != hdr->op) {
208 		bt_dev_err(hdev, "Wrong op received %d expected %d",
209 			   wmt_evt->whdr.op, hdr->op);
210 		err = -EIO;
211 		goto err_free_skb;
212 	}
213 
214 	switch (wmt_evt->whdr.op) {
215 	case MTK_WMT_SEMAPHORE:
216 		if (wmt_evt->whdr.flag == 2)
217 			status = BTMTK_WMT_PATCH_UNDONE;
218 		else
219 			status = BTMTK_WMT_PATCH_DONE;
220 		break;
221 	case MTK_WMT_FUNC_CTRL:
222 		wmt_evt_funcc = (struct btmtk_hci_wmt_evt_funcc *)wmt_evt;
223 		if (be16_to_cpu(wmt_evt_funcc->status) == 0x404)
224 			status = BTMTK_WMT_ON_DONE;
225 		else if (be16_to_cpu(wmt_evt_funcc->status) == 0x420)
226 			status = BTMTK_WMT_ON_PROGRESS;
227 		else
228 			status = BTMTK_WMT_ON_UNDONE;
229 		break;
230 	}
231 
232 	if (wmt_params->status)
233 		*wmt_params->status = status;
234 
235 err_free_skb:
236 	kfree_skb(bdev->evt_skb);
237 	bdev->evt_skb = NULL;
238 
239 	return err;
240 }
241 
242 static int mtk_setup_firmware(struct hci_dev *hdev, const char *fwname)
243 {
244 	struct btmtk_hci_wmt_params wmt_params;
245 	const struct firmware *fw;
246 	const u8 *fw_ptr;
247 	size_t fw_size;
248 	int err, dlen;
249 	u8 flag;
250 
251 	err = request_firmware(&fw, fwname, &hdev->dev);
252 	if (err < 0) {
253 		bt_dev_err(hdev, "Failed to load firmware file (%d)", err);
254 		return err;
255 	}
256 
257 	fw_ptr = fw->data;
258 	fw_size = fw->size;
259 
260 	/* The size of patch header is 30 bytes, should be skip */
261 	if (fw_size < 30) {
262 		err = -EINVAL;
263 		goto free_fw;
264 	}
265 
266 	fw_size -= 30;
267 	fw_ptr += 30;
268 	flag = 1;
269 
270 	wmt_params.op = MTK_WMT_PATCH_DWNLD;
271 	wmt_params.status = NULL;
272 
273 	while (fw_size > 0) {
274 		dlen = min_t(int, 250, fw_size);
275 
276 		/* Tell device the position in sequence */
277 		if (fw_size - dlen <= 0)
278 			flag = 3;
279 		else if (fw_size < fw->size - 30)
280 			flag = 2;
281 
282 		wmt_params.flag = flag;
283 		wmt_params.dlen = dlen;
284 		wmt_params.data = fw_ptr;
285 
286 		err = mtk_hci_wmt_sync(hdev, &wmt_params);
287 		if (err < 0) {
288 			bt_dev_err(hdev, "Failed to send wmt patch dwnld (%d)",
289 				   err);
290 			goto free_fw;
291 		}
292 
293 		fw_size -= dlen;
294 		fw_ptr += dlen;
295 	}
296 
297 	wmt_params.op = MTK_WMT_RST;
298 	wmt_params.flag = 4;
299 	wmt_params.dlen = 0;
300 	wmt_params.data = NULL;
301 	wmt_params.status = NULL;
302 
303 	/* Activate funciton the firmware providing to */
304 	err = mtk_hci_wmt_sync(hdev, &wmt_params);
305 	if (err < 0) {
306 		bt_dev_err(hdev, "Failed to send wmt rst (%d)", err);
307 		goto free_fw;
308 	}
309 
310 	/* Wait a few moments for firmware activation done */
311 	usleep_range(10000, 12000);
312 
313 free_fw:
314 	release_firmware(fw);
315 	return err;
316 }
317 
318 static int btmtkuart_recv_event(struct hci_dev *hdev, struct sk_buff *skb)
319 {
320 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
321 	struct hci_event_hdr *hdr = (void *)skb->data;
322 	int err;
323 
324 	/* Fix up the vendor event id with 0xff for vendor specific instead
325 	 * of 0xe4 so that event send via monitoring socket can be parsed
326 	 * properly.
327 	 */
328 	if (hdr->evt == 0xe4)
329 		hdr->evt = HCI_EV_VENDOR;
330 
331 	/* When someone waits for the WMT event, the skb is being cloned
332 	 * and being processed the events from there then.
333 	 */
334 	if (test_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state)) {
335 		bdev->evt_skb = skb_clone(skb, GFP_KERNEL);
336 		if (!bdev->evt_skb) {
337 			err = -ENOMEM;
338 			goto err_out;
339 		}
340 	}
341 
342 	err = hci_recv_frame(hdev, skb);
343 	if (err < 0)
344 		goto err_free_skb;
345 
346 	if (hdr->evt == HCI_EV_VENDOR) {
347 		if (test_and_clear_bit(BTMTKUART_TX_WAIT_VND_EVT,
348 				       &bdev->tx_state)) {
349 			/* Barrier to sync with other CPUs */
350 			smp_mb__after_atomic();
351 			wake_up_bit(&bdev->tx_state, BTMTKUART_TX_WAIT_VND_EVT);
352 		}
353 	}
354 
355 	return 0;
356 
357 err_free_skb:
358 	kfree_skb(bdev->evt_skb);
359 	bdev->evt_skb = NULL;
360 
361 err_out:
362 	return err;
363 }
364 
365 static const struct h4_recv_pkt mtk_recv_pkts[] = {
366 	{ H4_RECV_ACL,      .recv = hci_recv_frame },
367 	{ H4_RECV_SCO,      .recv = hci_recv_frame },
368 	{ H4_RECV_EVENT,    .recv = btmtkuart_recv_event },
369 };
370 
371 static void btmtkuart_tx_work(struct work_struct *work)
372 {
373 	struct btmtkuart_dev *bdev = container_of(work, struct btmtkuart_dev,
374 						   tx_work);
375 	struct serdev_device *serdev = bdev->serdev;
376 	struct hci_dev *hdev = bdev->hdev;
377 
378 	while (1) {
379 		clear_bit(BTMTKUART_TX_STATE_WAKEUP, &bdev->tx_state);
380 
381 		while (1) {
382 			struct sk_buff *skb = skb_dequeue(&bdev->txq);
383 			int len;
384 
385 			if (!skb)
386 				break;
387 
388 			len = serdev_device_write_buf(serdev, skb->data,
389 						      skb->len);
390 			hdev->stat.byte_tx += len;
391 
392 			skb_pull(skb, len);
393 			if (skb->len > 0) {
394 				skb_queue_head(&bdev->txq, skb);
395 				break;
396 			}
397 
398 			switch (hci_skb_pkt_type(skb)) {
399 			case HCI_COMMAND_PKT:
400 				hdev->stat.cmd_tx++;
401 				break;
402 			case HCI_ACLDATA_PKT:
403 				hdev->stat.acl_tx++;
404 				break;
405 			case HCI_SCODATA_PKT:
406 				hdev->stat.sco_tx++;
407 				break;
408 			}
409 
410 			kfree_skb(skb);
411 		}
412 
413 		if (!test_bit(BTMTKUART_TX_STATE_WAKEUP, &bdev->tx_state))
414 			break;
415 	}
416 
417 	clear_bit(BTMTKUART_TX_STATE_ACTIVE, &bdev->tx_state);
418 }
419 
420 static void btmtkuart_tx_wakeup(struct btmtkuart_dev *bdev)
421 {
422 	if (test_and_set_bit(BTMTKUART_TX_STATE_ACTIVE, &bdev->tx_state))
423 		set_bit(BTMTKUART_TX_STATE_WAKEUP, &bdev->tx_state);
424 
425 	schedule_work(&bdev->tx_work);
426 }
427 
428 static const unsigned char *
429 mtk_stp_split(struct btmtkuart_dev *bdev, const unsigned char *data, int count,
430 	      int *sz_h4)
431 {
432 	struct mtk_stp_hdr *shdr;
433 
434 	/* The cursor is reset when all the data of STP is consumed out */
435 	if (!bdev->stp_dlen && bdev->stp_cursor >= 6)
436 		bdev->stp_cursor = 0;
437 
438 	/* Filling pad until all STP info is obtained */
439 	while (bdev->stp_cursor < 6 && count > 0) {
440 		bdev->stp_pad[bdev->stp_cursor] = *data;
441 		bdev->stp_cursor++;
442 		data++;
443 		count--;
444 	}
445 
446 	/* Retrieve STP info and have a sanity check */
447 	if (!bdev->stp_dlen && bdev->stp_cursor >= 6) {
448 		shdr = (struct mtk_stp_hdr *)&bdev->stp_pad[2];
449 		bdev->stp_dlen = be16_to_cpu(shdr->dlen) & 0x0fff;
450 
451 		/* Resync STP when unexpected data is being read */
452 		if (shdr->prefix != 0x80 || bdev->stp_dlen > 2048) {
453 			bt_dev_err(bdev->hdev, "stp format unexpect (%d, %d)",
454 				   shdr->prefix, bdev->stp_dlen);
455 			bdev->stp_cursor = 2;
456 			bdev->stp_dlen = 0;
457 		}
458 	}
459 
460 	/* Directly quit when there's no data found for H4 can process */
461 	if (count <= 0)
462 		return NULL;
463 
464 	/* Tranlate to how much the size of data H4 can handle so far */
465 	*sz_h4 = min_t(int, count, bdev->stp_dlen);
466 
467 	/* Update the remaining size of STP packet */
468 	bdev->stp_dlen -= *sz_h4;
469 
470 	/* Data points to STP payload which can be handled by H4 */
471 	return data;
472 }
473 
474 static int btmtkuart_recv(struct hci_dev *hdev, const u8 *data, size_t count)
475 {
476 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
477 	const unsigned char *p_left = data, *p_h4;
478 	int sz_left = count, sz_h4, adv;
479 	int err;
480 
481 	while (sz_left > 0) {
482 		/*  The serial data received from MT7622 BT controller is
483 		 *  at all time padded around with the STP header and tailer.
484 		 *
485 		 *  A full STP packet is looking like
486 		 *   -----------------------------------
487 		 *  | STP header  |  H:4   | STP tailer |
488 		 *   -----------------------------------
489 		 *  but it doesn't guarantee to contain a full H:4 packet which
490 		 *  means that it's possible for multiple STP packets forms a
491 		 *  full H:4 packet that means extra STP header + length doesn't
492 		 *  indicate a full H:4 frame, things can fragment. Whose length
493 		 *  recorded in STP header just shows up the most length the
494 		 *  H:4 engine can handle currently.
495 		 */
496 
497 		p_h4 = mtk_stp_split(bdev, p_left, sz_left, &sz_h4);
498 		if (!p_h4)
499 			break;
500 
501 		adv = p_h4 - p_left;
502 		sz_left -= adv;
503 		p_left += adv;
504 
505 		bdev->rx_skb = h4_recv_buf(bdev->hdev, bdev->rx_skb, p_h4,
506 					   sz_h4, mtk_recv_pkts,
507 					   ARRAY_SIZE(mtk_recv_pkts));
508 		if (IS_ERR(bdev->rx_skb)) {
509 			err = PTR_ERR(bdev->rx_skb);
510 			bt_dev_err(bdev->hdev,
511 				   "Frame reassembly failed (%d)", err);
512 			bdev->rx_skb = NULL;
513 			return err;
514 		}
515 
516 		sz_left -= sz_h4;
517 		p_left += sz_h4;
518 	}
519 
520 	return 0;
521 }
522 
523 static int btmtkuart_receive_buf(struct serdev_device *serdev, const u8 *data,
524 				 size_t count)
525 {
526 	struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev);
527 	int err;
528 
529 	err = btmtkuart_recv(bdev->hdev, data, count);
530 	if (err < 0)
531 		return err;
532 
533 	bdev->hdev->stat.byte_rx += count;
534 
535 	return count;
536 }
537 
538 static void btmtkuart_write_wakeup(struct serdev_device *serdev)
539 {
540 	struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev);
541 
542 	btmtkuart_tx_wakeup(bdev);
543 }
544 
545 static const struct serdev_device_ops btmtkuart_client_ops = {
546 	.receive_buf = btmtkuart_receive_buf,
547 	.write_wakeup = btmtkuart_write_wakeup,
548 };
549 
550 static int btmtkuart_open(struct hci_dev *hdev)
551 {
552 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
553 	struct device *dev;
554 	int err;
555 
556 	err = serdev_device_open(bdev->serdev);
557 	if (err) {
558 		bt_dev_err(hdev, "Unable to open UART device %s",
559 			   dev_name(&bdev->serdev->dev));
560 		goto err_open;
561 	}
562 
563 	if (btmtkuart_is_standalone(bdev)) {
564 		if (bdev->curr_speed != bdev->desired_speed)
565 			err = serdev_device_set_baudrate(bdev->serdev,
566 							 115200);
567 		else
568 			err = serdev_device_set_baudrate(bdev->serdev,
569 							 bdev->desired_speed);
570 
571 		if (err < 0) {
572 			bt_dev_err(hdev, "Unable to set baudrate UART device %s",
573 				   dev_name(&bdev->serdev->dev));
574 			goto  err_serdev_close;
575 		}
576 
577 		serdev_device_set_flow_control(bdev->serdev, false);
578 	}
579 
580 	bdev->stp_cursor = 2;
581 	bdev->stp_dlen = 0;
582 
583 	dev = &bdev->serdev->dev;
584 
585 	/* Enable the power domain and clock the device requires */
586 	pm_runtime_enable(dev);
587 	err = pm_runtime_resume_and_get(dev);
588 	if (err < 0)
589 		goto err_disable_rpm;
590 
591 	err = clk_prepare_enable(bdev->clk);
592 	if (err < 0)
593 		goto err_put_rpm;
594 
595 	return 0;
596 
597 err_put_rpm:
598 	pm_runtime_put_sync(dev);
599 err_disable_rpm:
600 	pm_runtime_disable(dev);
601 err_serdev_close:
602 	serdev_device_close(bdev->serdev);
603 err_open:
604 	return err;
605 }
606 
607 static int btmtkuart_close(struct hci_dev *hdev)
608 {
609 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
610 	struct device *dev = &bdev->serdev->dev;
611 
612 	/* Shutdown the clock and power domain the device requires */
613 	clk_disable_unprepare(bdev->clk);
614 	pm_runtime_put_sync(dev);
615 	pm_runtime_disable(dev);
616 
617 	serdev_device_close(bdev->serdev);
618 
619 	return 0;
620 }
621 
622 static int btmtkuart_flush(struct hci_dev *hdev)
623 {
624 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
625 
626 	/* Flush any pending characters */
627 	serdev_device_write_flush(bdev->serdev);
628 	skb_queue_purge(&bdev->txq);
629 
630 	cancel_work_sync(&bdev->tx_work);
631 
632 	kfree_skb(bdev->rx_skb);
633 	bdev->rx_skb = NULL;
634 
635 	bdev->stp_cursor = 2;
636 	bdev->stp_dlen = 0;
637 
638 	return 0;
639 }
640 
641 static int btmtkuart_func_query(struct hci_dev *hdev)
642 {
643 	struct btmtk_hci_wmt_params wmt_params;
644 	int status, err;
645 	u8 param = 0;
646 
647 	/* Query whether the function is enabled */
648 	wmt_params.op = MTK_WMT_FUNC_CTRL;
649 	wmt_params.flag = 4;
650 	wmt_params.dlen = sizeof(param);
651 	wmt_params.data = &param;
652 	wmt_params.status = &status;
653 
654 	err = mtk_hci_wmt_sync(hdev, &wmt_params);
655 	if (err < 0) {
656 		bt_dev_err(hdev, "Failed to query function status (%d)", err);
657 		return err;
658 	}
659 
660 	return status;
661 }
662 
663 static int btmtkuart_change_baudrate(struct hci_dev *hdev)
664 {
665 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
666 	struct btmtk_hci_wmt_params wmt_params;
667 	__le32 baudrate;
668 	u8 param;
669 	int err;
670 
671 	/* Indicate the device to enter the probe state the host is
672 	 * ready to change a new baudrate.
673 	 */
674 	baudrate = cpu_to_le32(bdev->desired_speed);
675 	wmt_params.op = MTK_WMT_HIF;
676 	wmt_params.flag = 1;
677 	wmt_params.dlen = 4;
678 	wmt_params.data = &baudrate;
679 	wmt_params.status = NULL;
680 
681 	err = mtk_hci_wmt_sync(hdev, &wmt_params);
682 	if (err < 0) {
683 		bt_dev_err(hdev, "Failed to device baudrate (%d)", err);
684 		return err;
685 	}
686 
687 	err = serdev_device_set_baudrate(bdev->serdev,
688 					 bdev->desired_speed);
689 	if (err < 0) {
690 		bt_dev_err(hdev, "Failed to set up host baudrate (%d)",
691 			   err);
692 		return err;
693 	}
694 
695 	serdev_device_set_flow_control(bdev->serdev, false);
696 
697 	/* Send a dummy byte 0xff to activate the new baudrate */
698 	param = 0xff;
699 	err = serdev_device_write_buf(bdev->serdev, &param, sizeof(param));
700 	if (err < 0 || err < sizeof(param))
701 		return err;
702 
703 	serdev_device_wait_until_sent(bdev->serdev, 0);
704 
705 	/* Wait some time for the device changing baudrate done */
706 	usleep_range(20000, 22000);
707 
708 	/* Test the new baudrate */
709 	wmt_params.op = MTK_WMT_TEST;
710 	wmt_params.flag = 7;
711 	wmt_params.dlen = 0;
712 	wmt_params.data = NULL;
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 test new baudrate (%d)",
718 			   err);
719 		return err;
720 	}
721 
722 	bdev->curr_speed = bdev->desired_speed;
723 
724 	return 0;
725 }
726 
727 static int btmtkuart_setup(struct hci_dev *hdev)
728 {
729 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
730 	struct btmtk_hci_wmt_params wmt_params;
731 	ktime_t calltime, delta, rettime;
732 	struct btmtk_tci_sleep tci_sleep;
733 	unsigned long long duration;
734 	struct sk_buff *skb;
735 	int err, status;
736 	u8 param = 0x1;
737 
738 	calltime = ktime_get();
739 
740 	/* Wakeup MCUSYS is required for certain devices before we start to
741 	 * do any setups.
742 	 */
743 	if (test_bit(BTMTKUART_REQUIRED_WAKEUP, &bdev->tx_state)) {
744 		wmt_params.op = MTK_WMT_WAKEUP;
745 		wmt_params.flag = 3;
746 		wmt_params.dlen = 0;
747 		wmt_params.data = NULL;
748 		wmt_params.status = NULL;
749 
750 		err = mtk_hci_wmt_sync(hdev, &wmt_params);
751 		if (err < 0) {
752 			bt_dev_err(hdev, "Failed to wakeup the chip (%d)", err);
753 			return err;
754 		}
755 
756 		clear_bit(BTMTKUART_REQUIRED_WAKEUP, &bdev->tx_state);
757 	}
758 
759 	if (btmtkuart_is_standalone(bdev))
760 		btmtkuart_change_baudrate(hdev);
761 
762 	/* Query whether the firmware is already download */
763 	wmt_params.op = MTK_WMT_SEMAPHORE;
764 	wmt_params.flag = 1;
765 	wmt_params.dlen = 0;
766 	wmt_params.data = NULL;
767 	wmt_params.status = &status;
768 
769 	err = mtk_hci_wmt_sync(hdev, &wmt_params);
770 	if (err < 0) {
771 		bt_dev_err(hdev, "Failed to query firmware status (%d)", err);
772 		return err;
773 	}
774 
775 	if (status == BTMTK_WMT_PATCH_DONE) {
776 		bt_dev_info(hdev, "Firmware already downloaded");
777 		goto ignore_setup_fw;
778 	}
779 
780 	/* Setup a firmware which the device definitely requires */
781 	err = mtk_setup_firmware(hdev, bdev->data->fwname);
782 	if (err < 0)
783 		return err;
784 
785 ignore_setup_fw:
786 	/* Query whether the device is already enabled */
787 	err = readx_poll_timeout(btmtkuart_func_query, hdev, status,
788 				 status < 0 || status != BTMTK_WMT_ON_PROGRESS,
789 				 2000, 5000000);
790 	/* -ETIMEDOUT happens */
791 	if (err < 0)
792 		return err;
793 
794 	/* The other errors happen in btusb_mtk_func_query */
795 	if (status < 0)
796 		return status;
797 
798 	if (status == BTMTK_WMT_ON_DONE) {
799 		bt_dev_info(hdev, "function already on");
800 		goto ignore_func_on;
801 	}
802 
803 	/* Enable Bluetooth protocol */
804 	wmt_params.op = MTK_WMT_FUNC_CTRL;
805 	wmt_params.flag = 0;
806 	wmt_params.dlen = sizeof(param);
807 	wmt_params.data = &param;
808 	wmt_params.status = NULL;
809 
810 	err = mtk_hci_wmt_sync(hdev, &wmt_params);
811 	if (err < 0) {
812 		bt_dev_err(hdev, "Failed to send wmt func ctrl (%d)", err);
813 		return err;
814 	}
815 
816 ignore_func_on:
817 	/* Apply the low power environment setup */
818 	tci_sleep.mode = 0x5;
819 	tci_sleep.duration = cpu_to_le16(0x640);
820 	tci_sleep.host_duration = cpu_to_le16(0x640);
821 	tci_sleep.host_wakeup_pin = 0;
822 	tci_sleep.time_compensation = 0;
823 
824 	skb = __hci_cmd_sync(hdev, 0xfc7a, sizeof(tci_sleep), &tci_sleep,
825 			     HCI_INIT_TIMEOUT);
826 	if (IS_ERR(skb)) {
827 		err = PTR_ERR(skb);
828 		bt_dev_err(hdev, "Failed to apply low power setting (%d)", err);
829 		return err;
830 	}
831 	kfree_skb(skb);
832 
833 	rettime = ktime_get();
834 	delta = ktime_sub(rettime, calltime);
835 	duration = (unsigned long long)ktime_to_ns(delta) >> 10;
836 
837 	bt_dev_info(hdev, "Device setup in %llu usecs", duration);
838 
839 	return 0;
840 }
841 
842 static int btmtkuart_shutdown(struct hci_dev *hdev)
843 {
844 	struct btmtk_hci_wmt_params wmt_params;
845 	u8 param = 0x0;
846 	int err;
847 
848 	/* Disable the device */
849 	wmt_params.op = MTK_WMT_FUNC_CTRL;
850 	wmt_params.flag = 0;
851 	wmt_params.dlen = sizeof(param);
852 	wmt_params.data = &param;
853 	wmt_params.status = NULL;
854 
855 	err = mtk_hci_wmt_sync(hdev, &wmt_params);
856 	if (err < 0) {
857 		bt_dev_err(hdev, "Failed to send wmt func ctrl (%d)", err);
858 		return err;
859 	}
860 
861 	return 0;
862 }
863 
864 static int btmtkuart_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
865 {
866 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
867 	struct mtk_stp_hdr *shdr;
868 	int err, dlen, type = 0;
869 
870 	/* Prepend skb with frame type */
871 	memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);
872 
873 	/* Make sure that there is enough rooms for STP header and trailer */
874 	if (unlikely(skb_headroom(skb) < sizeof(*shdr)) ||
875 	    (skb_tailroom(skb) < MTK_STP_TLR_SIZE)) {
876 		err = pskb_expand_head(skb, sizeof(*shdr), MTK_STP_TLR_SIZE,
877 				       GFP_ATOMIC);
878 		if (err < 0)
879 			return err;
880 	}
881 
882 	/* Add the STP header */
883 	dlen = skb->len;
884 	shdr = skb_push(skb, sizeof(*shdr));
885 	shdr->prefix = 0x80;
886 	shdr->dlen = cpu_to_be16((dlen & 0x0fff) | (type << 12));
887 	shdr->cs = 0;		/* MT7622 doesn't care about checksum value */
888 
889 	/* Add the STP trailer */
890 	skb_put_zero(skb, MTK_STP_TLR_SIZE);
891 
892 	skb_queue_tail(&bdev->txq, skb);
893 
894 	btmtkuart_tx_wakeup(bdev);
895 	return 0;
896 }
897 
898 static int btmtkuart_parse_dt(struct serdev_device *serdev)
899 {
900 	struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev);
901 	struct device_node *node = serdev->dev.of_node;
902 	u32 speed = 921600;
903 	int err;
904 
905 	if (btmtkuart_is_standalone(bdev)) {
906 		of_property_read_u32(node, "current-speed", &speed);
907 
908 		bdev->desired_speed = speed;
909 
910 		bdev->vcc = devm_regulator_get(&serdev->dev, "vcc");
911 		if (IS_ERR(bdev->vcc)) {
912 			err = PTR_ERR(bdev->vcc);
913 			return err;
914 		}
915 
916 		bdev->osc = devm_clk_get_optional(&serdev->dev, "osc");
917 		if (IS_ERR(bdev->osc)) {
918 			err = PTR_ERR(bdev->osc);
919 			return err;
920 		}
921 
922 		bdev->boot = devm_gpiod_get_optional(&serdev->dev, "boot",
923 						     GPIOD_OUT_LOW);
924 		if (IS_ERR(bdev->boot)) {
925 			err = PTR_ERR(bdev->boot);
926 			return err;
927 		}
928 
929 		bdev->pinctrl = devm_pinctrl_get(&serdev->dev);
930 		if (IS_ERR(bdev->pinctrl)) {
931 			err = PTR_ERR(bdev->pinctrl);
932 			return err;
933 		}
934 
935 		bdev->pins_boot = pinctrl_lookup_state(bdev->pinctrl,
936 						       "default");
937 		if (IS_ERR(bdev->pins_boot) && !bdev->boot) {
938 			err = PTR_ERR(bdev->pins_boot);
939 			dev_err(&serdev->dev,
940 				"Should assign RXD to LOW at boot stage\n");
941 			return err;
942 		}
943 
944 		bdev->pins_runtime = pinctrl_lookup_state(bdev->pinctrl,
945 							  "runtime");
946 		if (IS_ERR(bdev->pins_runtime)) {
947 			err = PTR_ERR(bdev->pins_runtime);
948 			return err;
949 		}
950 
951 		bdev->reset = devm_gpiod_get_optional(&serdev->dev, "reset",
952 						      GPIOD_OUT_LOW);
953 		if (IS_ERR(bdev->reset)) {
954 			err = PTR_ERR(bdev->reset);
955 			return err;
956 		}
957 	} else if (btmtkuart_is_builtin_soc(bdev)) {
958 		bdev->clk = devm_clk_get(&serdev->dev, "ref");
959 		if (IS_ERR(bdev->clk))
960 			return PTR_ERR(bdev->clk);
961 	}
962 
963 	return 0;
964 }
965 
966 static int btmtkuart_probe(struct serdev_device *serdev)
967 {
968 	struct btmtkuart_dev *bdev;
969 	struct hci_dev *hdev;
970 	int err;
971 
972 	bdev = devm_kzalloc(&serdev->dev, sizeof(*bdev), GFP_KERNEL);
973 	if (!bdev)
974 		return -ENOMEM;
975 
976 	bdev->data = of_device_get_match_data(&serdev->dev);
977 	if (!bdev->data)
978 		return -ENODEV;
979 
980 	bdev->serdev = serdev;
981 	serdev_device_set_drvdata(serdev, bdev);
982 
983 	serdev_device_set_client_ops(serdev, &btmtkuart_client_ops);
984 
985 	err = btmtkuart_parse_dt(serdev);
986 	if (err < 0)
987 		return err;
988 
989 	INIT_WORK(&bdev->tx_work, btmtkuart_tx_work);
990 	skb_queue_head_init(&bdev->txq);
991 
992 	/* Initialize and register HCI device */
993 	hdev = hci_alloc_dev();
994 	if (!hdev) {
995 		dev_err(&serdev->dev, "Can't allocate HCI device\n");
996 		return -ENOMEM;
997 	}
998 
999 	bdev->hdev = hdev;
1000 
1001 	hdev->bus = HCI_UART;
1002 	hci_set_drvdata(hdev, bdev);
1003 
1004 	hdev->open     = btmtkuart_open;
1005 	hdev->close    = btmtkuart_close;
1006 	hdev->flush    = btmtkuart_flush;
1007 	hdev->setup    = btmtkuart_setup;
1008 	hdev->shutdown = btmtkuart_shutdown;
1009 	hdev->send     = btmtkuart_send_frame;
1010 	SET_HCIDEV_DEV(hdev, &serdev->dev);
1011 
1012 	hdev->manufacturer = 70;
1013 	set_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks);
1014 
1015 	if (btmtkuart_is_standalone(bdev)) {
1016 		err = clk_prepare_enable(bdev->osc);
1017 		if (err < 0)
1018 			goto err_hci_free_dev;
1019 
1020 		if (bdev->boot) {
1021 			gpiod_set_value_cansleep(bdev->boot, 1);
1022 		} else {
1023 			/* Switch to the specific pin state for the booting
1024 			 * requires.
1025 			 */
1026 			pinctrl_select_state(bdev->pinctrl, bdev->pins_boot);
1027 		}
1028 
1029 		/* Power on */
1030 		err = regulator_enable(bdev->vcc);
1031 		if (err < 0)
1032 			goto err_clk_disable_unprepare;
1033 
1034 		/* Reset if the reset-gpios is available otherwise the board
1035 		 * -level design should be guaranteed.
1036 		 */
1037 		if (bdev->reset) {
1038 			gpiod_set_value_cansleep(bdev->reset, 1);
1039 			usleep_range(1000, 2000);
1040 			gpiod_set_value_cansleep(bdev->reset, 0);
1041 		}
1042 
1043 		/* Wait some time until device got ready and switch to the pin
1044 		 * mode the device requires for UART transfers.
1045 		 */
1046 		msleep(50);
1047 
1048 		if (bdev->boot)
1049 			devm_gpiod_put(&serdev->dev, bdev->boot);
1050 
1051 		pinctrl_select_state(bdev->pinctrl, bdev->pins_runtime);
1052 
1053 		/* A standalone device doesn't depends on power domain on SoC,
1054 		 * so mark it as no callbacks.
1055 		 */
1056 		pm_runtime_no_callbacks(&serdev->dev);
1057 
1058 		set_bit(BTMTKUART_REQUIRED_WAKEUP, &bdev->tx_state);
1059 	}
1060 
1061 	err = hci_register_dev(hdev);
1062 	if (err < 0) {
1063 		dev_err(&serdev->dev, "Can't register HCI device\n");
1064 		goto err_regulator_disable;
1065 	}
1066 
1067 	return 0;
1068 
1069 err_regulator_disable:
1070 	if (btmtkuart_is_standalone(bdev))
1071 		regulator_disable(bdev->vcc);
1072 err_clk_disable_unprepare:
1073 	if (btmtkuart_is_standalone(bdev))
1074 		clk_disable_unprepare(bdev->osc);
1075 err_hci_free_dev:
1076 	hci_free_dev(hdev);
1077 
1078 	return err;
1079 }
1080 
1081 static void btmtkuart_remove(struct serdev_device *serdev)
1082 {
1083 	struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev);
1084 	struct hci_dev *hdev = bdev->hdev;
1085 
1086 	if (btmtkuart_is_standalone(bdev)) {
1087 		regulator_disable(bdev->vcc);
1088 		clk_disable_unprepare(bdev->osc);
1089 	}
1090 
1091 	hci_unregister_dev(hdev);
1092 	hci_free_dev(hdev);
1093 }
1094 
1095 static const struct btmtkuart_data mt7622_data = {
1096 	.fwname = FIRMWARE_MT7622,
1097 };
1098 
1099 static const struct btmtkuart_data mt7663_data = {
1100 	.flags = BTMTKUART_FLAG_STANDALONE_HW,
1101 	.fwname = FIRMWARE_MT7663,
1102 };
1103 
1104 static const struct btmtkuart_data mt7668_data = {
1105 	.flags = BTMTKUART_FLAG_STANDALONE_HW,
1106 	.fwname = FIRMWARE_MT7668,
1107 };
1108 
1109 #ifdef CONFIG_OF
1110 static const struct of_device_id mtk_of_match_table[] = {
1111 	{ .compatible = "mediatek,mt7622-bluetooth", .data = &mt7622_data},
1112 	{ .compatible = "mediatek,mt7663u-bluetooth", .data = &mt7663_data},
1113 	{ .compatible = "mediatek,mt7668u-bluetooth", .data = &mt7668_data},
1114 	{ }
1115 };
1116 MODULE_DEVICE_TABLE(of, mtk_of_match_table);
1117 #endif
1118 
1119 static struct serdev_device_driver btmtkuart_driver = {
1120 	.probe = btmtkuart_probe,
1121 	.remove = btmtkuart_remove,
1122 	.driver = {
1123 		.name = "btmtkuart",
1124 		.of_match_table = of_match_ptr(mtk_of_match_table),
1125 	},
1126 };
1127 
1128 module_serdev_device_driver(btmtkuart_driver);
1129 
1130 MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
1131 MODULE_DESCRIPTION("MediaTek Bluetooth Serial driver ver " VERSION);
1132 MODULE_VERSION(VERSION);
1133 MODULE_LICENSE("GPL");
1134 MODULE_FIRMWARE(FIRMWARE_MT7622);
1135 MODULE_FIRMWARE(FIRMWARE_MT7663);
1136 MODULE_FIRMWARE(FIRMWARE_MT7668);
1137