drivers/bluetooth/btmtkuart.c - kernel/msm-5.4 - Gitiles

 // SPDX-License-Identifier: GPL-2.0
 // Copyright (c) 2018 MediaTek Inc.

 /*
  * Bluetooth support for MediaTek serial devices
  *
  * Author: Sean Wang <sean.wang@mediatek.com>
  *
  */

 #include <asm/unaligned.h>
 #include <linux/atomic.h>
 #include <linux/clk.h>
 #include <linux/firmware.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/pm_runtime.h>
 #include <linux/serdev.h>
 #include <linux/skbuff.h>

 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>

 #include "h4_recv.h"

 #define VERSION "0.1"

 #define FIRMWARE_MT7622		"mediatek/mt7622pr2h.bin"

 #define MTK_STP_TLR_SIZE	2

 #define BTMTKUART_TX_STATE_ACTIVE	1
 #define BTMTKUART_TX_STATE_WAKEUP	2
 #define BTMTKUART_TX_WAIT_VND_EVT	3

 enum {
 	MTK_WMT_PATCH_DWNLD = 0x1,
 	MTK_WMT_FUNC_CTRL = 0x6,
 	MTK_WMT_RST = 0x7
 };

 struct mtk_stp_hdr {
 	u8	prefix;
 	__be16	dlen;
 	u8	cs;
 } __packed;

 struct mtk_wmt_hdr {
 	u8	dir;
 	u8	op;
 	__le16	dlen;
 	u8	flag;
 } __packed;

 struct mtk_hci_wmt_cmd {
 	struct mtk_wmt_hdr hdr;
 	u8 data[256];
 } __packed;

 struct btmtkuart_dev {
 	struct hci_dev *hdev;
 	struct serdev_device *serdev;
 	struct clk *clk;

 	struct work_struct tx_work;
 	unsigned long tx_state;
 	struct sk_buff_head txq;

 	struct sk_buff *rx_skb;

 	u8	stp_pad[6];
 	u8	stp_cursor;
 	u16	stp_dlen;
 };

 static int mtk_hci_wmt_sync(struct hci_dev *hdev, u8 op, u8 flag, u16 plen,
 			    const void *param)
 {
 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
 	struct mtk_hci_wmt_cmd wc;
 	struct mtk_wmt_hdr *hdr;
 	u32 hlen;
 	int err;

 	hlen = sizeof(*hdr) + plen;
 	if (hlen > 255)
 		return -EINVAL;

 	hdr = (struct mtk_wmt_hdr *)&wc;
 	hdr->dir = 1;
 	hdr->op = op;
 	hdr->dlen = cpu_to_le16(plen + 1);
 	hdr->flag = flag;
 	memcpy(wc.data, param, plen);

 	set_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state);

 	err = __hci_cmd_send(hdev, 0xfc6f, hlen, &wc);
 	if (err < 0) {
 		clear_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state);
 		return err;
 	}

 	/* The vendor specific WMT commands are all answered by a vendor
 	 * specific event and will not have the Command Status or Command
 	 * Complete as with usual HCI command flow control.
 	 *
 	 * After sending the command, wait for BTMTKUART_TX_WAIT_VND_EVT
 	 * state to be cleared. The driver speicfic event receive routine
 	 * will clear that state and with that indicate completion of the
 	 * WMT command.
 	 */
 	err = wait_on_bit_timeout(&bdev->tx_state, BTMTKUART_TX_WAIT_VND_EVT,
 				  TASK_INTERRUPTIBLE, HCI_INIT_TIMEOUT);
 	if (err == -EINTR) {
 		bt_dev_err(hdev, "Execution of wmt command interrupted");
 		return err;
 	}

 	if (err) {
 		bt_dev_err(hdev, "Execution of wmt command timed out");
 		return -ETIMEDOUT;
 	}

 	return 0;
 }

 static int mtk_setup_fw(struct hci_dev *hdev)
 {
 	const struct firmware *fw;
 	const u8 *fw_ptr;
 	size_t fw_size;
 	int err, dlen;
 	u8 flag;

 	err = request_firmware(&fw, FIRMWARE_MT7622, &hdev->dev);
 	if (err < 0) {
 		bt_dev_err(hdev, "Failed to load firmware file (%d)", err);
 		return err;
 	}

 	fw_ptr = fw->data;
 	fw_size = fw->size;

 	/* The size of patch header is 30 bytes, should be skip */
 	if (fw_size < 30)
 		return -EINVAL;

 	fw_size -= 30;
 	fw_ptr += 30;
 	flag = 1;

 	while (fw_size > 0) {
 		dlen = min_t(int, 250, fw_size);

 		/* Tell device the position in sequence */
 		if (fw_size - dlen <= 0)
 			flag = 3;
 		else if (fw_size < fw->size - 30)
 			flag = 2;

 		err = mtk_hci_wmt_sync(hdev, MTK_WMT_PATCH_DWNLD, flag, dlen,
 				       fw_ptr);
 		if (err < 0) {
 			bt_dev_err(hdev, "Failed to send wmt patch dwnld (%d)",
 				   err);
 			break;
 		}

 		fw_size -= dlen;
 		fw_ptr += dlen;
 	}

 	release_firmware(fw);

 	return err;
 }

 static int btmtkuart_recv_event(struct hci_dev *hdev, struct sk_buff *skb)
 {
 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
 	struct hci_event_hdr *hdr = (void *)skb->data;
 	int err;

 	/* Fix up the vendor event id with 0xff for vendor specific instead
 	 * of 0xe4 so that event send via monitoring socket can be parsed
 	 * properly.
 	 */
 	if (hdr->evt == 0xe4)
 		hdr->evt = HCI_EV_VENDOR;

 	err = hci_recv_frame(hdev, skb);

 	if (hdr->evt == HCI_EV_VENDOR) {
 		if (test_and_clear_bit(BTMTKUART_TX_WAIT_VND_EVT,
 				       &bdev->tx_state)) {
 			/* Barrier to sync with other CPUs */
 			smp_mb__after_atomic();
 			wake_up_bit(&bdev->tx_state, BTMTKUART_TX_WAIT_VND_EVT);
 		}
 	}

 	return err;
 }

 static const struct h4_recv_pkt mtk_recv_pkts[] = {
 	{ H4_RECV_ACL,      .recv = hci_recv_frame },
 	{ H4_RECV_SCO,      .recv = hci_recv_frame },
 	{ H4_RECV_EVENT,    .recv = btmtkuart_recv_event },
 };

 static void btmtkuart_tx_work(struct work_struct *work)
 {
 	struct btmtkuart_dev *bdev = container_of(work, struct btmtkuart_dev,
 						   tx_work);
 	struct serdev_device *serdev = bdev->serdev;
 	struct hci_dev *hdev = bdev->hdev;

 	while (1) {
 		clear_bit(BTMTKUART_TX_STATE_WAKEUP, &bdev->tx_state);

 		while (1) {
 			struct sk_buff *skb = skb_dequeue(&bdev->txq);
 			int len;

 			if (!skb)
 				break;

 			len = serdev_device_write_buf(serdev, skb->data,
 						      skb->len);
 			hdev->stat.byte_tx += len;

 			skb_pull(skb, len);
 			if (skb->len > 0) {
 				skb_queue_head(&bdev->txq, skb);
 				break;
 			}

 			switch (hci_skb_pkt_type(skb)) {
 			case HCI_COMMAND_PKT:
 				hdev->stat.cmd_tx++;
 				break;
 			case HCI_ACLDATA_PKT:
 				hdev->stat.acl_tx++;
 				break;
 			case HCI_SCODATA_PKT:
 				hdev->stat.sco_tx++;
 				break;
 			}

 			kfree_skb(skb);
 		}

 		if (!test_bit(BTMTKUART_TX_STATE_WAKEUP, &bdev->tx_state))
 			break;
 	}

 	clear_bit(BTMTKUART_TX_STATE_ACTIVE, &bdev->tx_state);
 }

 static void btmtkuart_tx_wakeup(struct btmtkuart_dev *bdev)
 {
 	if (test_and_set_bit(BTMTKUART_TX_STATE_ACTIVE, &bdev->tx_state))
 		set_bit(BTMTKUART_TX_STATE_WAKEUP, &bdev->tx_state);

 	schedule_work(&bdev->tx_work);
 }

 static const unsigned char *
 mtk_stp_split(struct btmtkuart_dev *bdev, const unsigned char *data, int count,
 	      int *sz_h4)
 {
 	struct mtk_stp_hdr *shdr;

 	/* The cursor is reset when all the data of STP is consumed out */
 	if (!bdev->stp_dlen && bdev->stp_cursor >= 6)
 		bdev->stp_cursor = 0;

 	/* Filling pad until all STP info is obtained */
 	while (bdev->stp_cursor < 6 && count > 0) {
 		bdev->stp_pad[bdev->stp_cursor] = *data;
 		bdev->stp_cursor++;
 		data++;
 		count--;
 	}

 	/* Retrieve STP info and have a sanity check */
 	if (!bdev->stp_dlen && bdev->stp_cursor >= 6) {
 		shdr = (struct mtk_stp_hdr *)&bdev->stp_pad[2];
 		bdev->stp_dlen = be16_to_cpu(shdr->dlen) & 0x0fff;

 		/* Resync STP when unexpected data is being read */
 		if (shdr->prefix != 0x80 || bdev->stp_dlen > 2048) {
 			bt_dev_err(bdev->hdev, "stp format unexpect (%d, %d)",
 				   shdr->prefix, bdev->stp_dlen);
 			bdev->stp_cursor = 2;
 			bdev->stp_dlen = 0;
 		}
 	}

 	/* Directly quit when there's no data found for H4 can process */
 	if (count <= 0)
 		return NULL;

 	/* Tranlate to how much the size of data H4 can handle so far */
 	*sz_h4 = min_t(int, count, bdev->stp_dlen);

 	/* Update the remaining size of STP packet */
 	bdev->stp_dlen -= *sz_h4;

 	/* Data points to STP payload which can be handled by H4 */
 	return data;
 }

 static int btmtkuart_recv(struct hci_dev *hdev, const u8 *data, size_t count)
 {
 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
 	const unsigned char *p_left = data, *p_h4;
 	int sz_left = count, sz_h4, adv;
 	int err;

 	while (sz_left > 0) {
 		/*  The serial data received from MT7622 BT controller is
 		 *  at all time padded around with the STP header and tailer.
 		 *
 		 *  A full STP packet is looking like
 		 *   -----------------------------------
 		 *  | STP header  |  H:4   | STP tailer |
 		 *   -----------------------------------
 		 *  but it doesn't guarantee to contain a full H:4 packet which
 		 *  means that it's possible for multiple STP packets forms a
 		 *  full H:4 packet that means extra STP header + length doesn't
 		 *  indicate a full H:4 frame, things can fragment. Whose length
 		 *  recorded in STP header just shows up the most length the
 		 *  H:4 engine can handle currently.
 		 */

 		p_h4 = mtk_stp_split(bdev, p_left, sz_left, &sz_h4);
 		if (!p_h4)
 			break;

 		adv = p_h4 - p_left;
 		sz_left -= adv;
 		p_left += adv;

 		bdev->rx_skb = h4_recv_buf(bdev->hdev, bdev->rx_skb, p_h4,
 					   sz_h4, mtk_recv_pkts,
 					   ARRAY_SIZE(mtk_recv_pkts));
 		if (IS_ERR(bdev->rx_skb)) {
 			err = PTR_ERR(bdev->rx_skb);
 			bt_dev_err(bdev->hdev,
 				   "Frame reassembly failed (%d)", err);
 			bdev->rx_skb = NULL;
 			return err;
 		}

 		sz_left -= sz_h4;
 		p_left += sz_h4;
 	}

 	return 0;
 }

 static int btmtkuart_receive_buf(struct serdev_device *serdev, const u8 *data,
 				 size_t count)
 {
 	struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev);
 	int err;

 	err = btmtkuart_recv(bdev->hdev, data, count);
 	if (err < 0)
 		return err;

 	bdev->hdev->stat.byte_rx += count;

 	return count;
 }

 static void btmtkuart_write_wakeup(struct serdev_device *serdev)
 {
 	struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev);

 	btmtkuart_tx_wakeup(bdev);
 }

 static const struct serdev_device_ops btmtkuart_client_ops = {
 	.receive_buf = btmtkuart_receive_buf,
 	.write_wakeup = btmtkuart_write_wakeup,
 };

 static int btmtkuart_open(struct hci_dev *hdev)
 {
 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
 	struct device *dev;
 	int err;

 	err = serdev_device_open(bdev->serdev);
 	if (err) {
 		bt_dev_err(hdev, "Unable to open UART device %s",
 			   dev_name(&bdev->serdev->dev));
 		goto err_open;
 	}

 	bdev->stp_cursor = 2;
 	bdev->stp_dlen = 0;

 	dev = &bdev->serdev->dev;

 	/* Enable the power domain and clock the device requires */
 	pm_runtime_enable(dev);
 	err = pm_runtime_get_sync(dev);
 	if (err < 0) {
 		pm_runtime_put_noidle(dev);
 		goto err_disable_rpm;
 	}

 	err = clk_prepare_enable(bdev->clk);
 	if (err < 0)
 		goto err_put_rpm;

 	return 0;

 err_put_rpm:
 	pm_runtime_put_sync(dev);
 err_disable_rpm:
 	pm_runtime_disable(dev);
 err_open:
 	return err;
 }

 static int btmtkuart_close(struct hci_dev *hdev)
 {
 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
 	struct device *dev = &bdev->serdev->dev;

 	/* Shutdown the clock and power domain the device requires */
 	clk_disable_unprepare(bdev->clk);
 	pm_runtime_put_sync(dev);
 	pm_runtime_disable(dev);

 	serdev_device_close(bdev->serdev);

 	return 0;
 }

 static int btmtkuart_flush(struct hci_dev *hdev)
 {
 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);

 	/* Flush any pending characters */
 	serdev_device_write_flush(bdev->serdev);
 	skb_queue_purge(&bdev->txq);

 	cancel_work_sync(&bdev->tx_work);

 	kfree_skb(bdev->rx_skb);
 	bdev->rx_skb = NULL;

 	bdev->stp_cursor = 2;
 	bdev->stp_dlen = 0;

 	return 0;
 }

 static int btmtkuart_setup(struct hci_dev *hdev)
 {
 	u8 param = 0x1;
 	int err = 0;

 	/* Setup a firmware which the device definitely requires */
 	err = mtk_setup_fw(hdev);
 	if (err < 0)
 		return err;

 	/* Activate function the firmware providing to */
 	err = mtk_hci_wmt_sync(hdev, MTK_WMT_RST, 0x4, 0, 0);
 	if (err < 0) {
 		bt_dev_err(hdev, "Failed to send wmt rst (%d)", err);
 		return err;
 	}

 	/* Enable Bluetooth protocol */
 	err = mtk_hci_wmt_sync(hdev, MTK_WMT_FUNC_CTRL, 0x0, sizeof(param),
 			       &param);
 	if (err < 0) {
 		bt_dev_err(hdev, "Failed to send wmt func ctrl (%d)", err);
 		return err;
 	}

 	return 0;
 }

 static int btmtkuart_shutdown(struct hci_dev *hdev)
 {
 	u8 param = 0x0;
 	int err;

 	/* Disable the device */
 	err = mtk_hci_wmt_sync(hdev, MTK_WMT_FUNC_CTRL, 0x0, sizeof(param),
 			       &param);
 	if (err < 0) {
 		bt_dev_err(hdev, "Failed to send wmt func ctrl (%d)", err);
 		return err;
 	}

 	return 0;
 }

 static int btmtkuart_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
 {
 	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
 	struct mtk_stp_hdr *shdr;
 	int err, dlen, type = 0;

 	/* Prepend skb with frame type */
 	memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);

 	/* Make sure that there is enough rooms for STP header and trailer */
 	if (unlikely(skb_headroom(skb) < sizeof(*shdr)) ||
 	    (skb_tailroom(skb) < MTK_STP_TLR_SIZE)) {
 		err = pskb_expand_head(skb, sizeof(*shdr), MTK_STP_TLR_SIZE,
 				       GFP_ATOMIC);
 		if (err < 0)
 			return err;
 	}

 	/* Add the STP header */
 	dlen = skb->len;
 	shdr = skb_push(skb, sizeof(*shdr));
 	shdr->prefix = 0x80;
 	shdr->dlen = cpu_to_be16((dlen & 0x0fff) | (type << 12));
 	shdr->cs = 0;		/* MT7622 doesn't care about checksum value */

 	/* Add the STP trailer */
 	skb_put_zero(skb, MTK_STP_TLR_SIZE);

 	skb_queue_tail(&bdev->txq, skb);

 	btmtkuart_tx_wakeup(bdev);
 	return 0;
 }

 static int btmtkuart_probe(struct serdev_device *serdev)
 {
 	struct btmtkuart_dev *bdev;
 	struct hci_dev *hdev;

 	bdev = devm_kzalloc(&serdev->dev, sizeof(*bdev), GFP_KERNEL);
 	if (!bdev)
 		return -ENOMEM;

 	bdev->clk = devm_clk_get(&serdev->dev, "ref");
 	if (IS_ERR(bdev->clk))
 		return PTR_ERR(bdev->clk);

 	bdev->serdev = serdev;
 	serdev_device_set_drvdata(serdev, bdev);

 	serdev_device_set_client_ops(serdev, &btmtkuart_client_ops);

 	INIT_WORK(&bdev->tx_work, btmtkuart_tx_work);
 	skb_queue_head_init(&bdev->txq);

 	/* Initialize and register HCI device */
 	hdev = hci_alloc_dev();
 	if (!hdev) {
 		dev_err(&serdev->dev, "Can't allocate HCI device\n");
 		return -ENOMEM;
 	}

 	bdev->hdev = hdev;

 	hdev->bus = HCI_UART;
 	hci_set_drvdata(hdev, bdev);

 	hdev->open     = btmtkuart_open;
 	hdev->close    = btmtkuart_close;
 	hdev->flush    = btmtkuart_flush;
 	hdev->setup    = btmtkuart_setup;
 	hdev->shutdown = btmtkuart_shutdown;
 	hdev->send     = btmtkuart_send_frame;
 	SET_HCIDEV_DEV(hdev, &serdev->dev);

 	hdev->manufacturer = 70;
 	set_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks);

 	if (hci_register_dev(hdev) < 0) {
 		dev_err(&serdev->dev, "Can't register HCI device\n");
 		hci_free_dev(hdev);
 		return -ENODEV;
 	}

 	return 0;
 }

 static void btmtkuart_remove(struct serdev_device *serdev)
 {
 	struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev);
 	struct hci_dev *hdev = bdev->hdev;

 	hci_unregister_dev(hdev);
 	hci_free_dev(hdev);
 }

 #ifdef CONFIG_OF
 static const struct of_device_id mtk_of_match_table[] = {
 	{ .compatible = "mediatek,mt7622-bluetooth"},
 	{ }
 };
 MODULE_DEVICE_TABLE(of, mtk_of_match_table);
 #endif

 static struct serdev_device_driver btmtkuart_driver = {
 	.probe = btmtkuart_probe,
 	.remove = btmtkuart_remove,
 	.driver = {
 		.name = "btmtkuart",
 		.of_match_table = of_match_ptr(mtk_of_match_table),
 	},
 };

 module_serdev_device_driver(btmtkuart_driver);

 MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
 MODULE_DESCRIPTION("MediaTek Bluetooth Serial driver ver " VERSION);
 MODULE_VERSION(VERSION);
 MODULE_LICENSE("GPL");
 MODULE_FIRMWARE(FIRMWARE_MT7622);
	// SPDX-License-Identifier: GPL-2.0
	// Copyright (c) 2018 MediaTek Inc.

	/*
	* Bluetooth support for MediaTek serial devices
	*
	* Author: Sean Wang <sean.wang@mediatek.com>
	*
	*/

	#include <asm/unaligned.h>
	#include <linux/atomic.h>
	#include <linux/clk.h>
	#include <linux/firmware.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/pm_runtime.h>
	#include <linux/serdev.h>
	#include <linux/skbuff.h>

	#include <net/bluetooth/bluetooth.h>
	#include <net/bluetooth/hci_core.h>

	#include "h4_recv.h"

	#define VERSION "0.1"

	#define FIRMWARE_MT7622 "mediatek/mt7622pr2h.bin"

	#define MTK_STP_TLR_SIZE 2

	#define BTMTKUART_TX_STATE_ACTIVE 1
	#define BTMTKUART_TX_STATE_WAKEUP 2
	#define BTMTKUART_TX_WAIT_VND_EVT 3

	enum {
	MTK_WMT_PATCH_DWNLD = 0x1,
	MTK_WMT_FUNC_CTRL = 0x6,
	MTK_WMT_RST = 0x7
	};

	struct mtk_stp_hdr {
	u8 prefix;
	__be16 dlen;
	u8 cs;
	} __packed;

	struct mtk_wmt_hdr {
	u8 dir;
	u8 op;
	__le16 dlen;
	u8 flag;
	} __packed;

	struct mtk_hci_wmt_cmd {
	struct mtk_wmt_hdr hdr;
	u8 data[256];
	} __packed;

	struct btmtkuart_dev {
	struct hci_dev *hdev;
	struct serdev_device *serdev;
	struct clk *clk;

	struct work_struct tx_work;
	unsigned long tx_state;
	struct sk_buff_head txq;

	struct sk_buff *rx_skb;

	u8 stp_pad[6];
	u8 stp_cursor;
	u16 stp_dlen;
	};

	static int mtk_hci_wmt_sync(struct hci_dev *hdev, u8 op, u8 flag, u16 plen,
	const void *param)
	{
	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
	struct mtk_hci_wmt_cmd wc;
	struct mtk_wmt_hdr *hdr;
	u32 hlen;
	int err;

	hlen = sizeof(*hdr) + plen;
	if (hlen > 255)
	return -EINVAL;

	hdr = (struct mtk_wmt_hdr *)&wc;
	hdr->dir = 1;
	hdr->op = op;
	hdr->dlen = cpu_to_le16(plen + 1);
	hdr->flag = flag;
	memcpy(wc.data, param, plen);

	set_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state);

	err = __hci_cmd_send(hdev, 0xfc6f, hlen, &wc);
	if (err < 0) {
	clear_bit(BTMTKUART_TX_WAIT_VND_EVT, &bdev->tx_state);
	return err;
	}

	/* The vendor specific WMT commands are all answered by a vendor
	* specific event and will not have the Command Status or Command
	* Complete as with usual HCI command flow control.
	*
	* After sending the command, wait for BTMTKUART_TX_WAIT_VND_EVT
	* state to be cleared. The driver speicfic event receive routine
	* will clear that state and with that indicate completion of the
	* WMT command.
	*/
	err = wait_on_bit_timeout(&bdev->tx_state, BTMTKUART_TX_WAIT_VND_EVT,
	TASK_INTERRUPTIBLE, HCI_INIT_TIMEOUT);
	if (err == -EINTR) {
	bt_dev_err(hdev, "Execution of wmt command interrupted");
	return err;
	}

	if (err) {
	bt_dev_err(hdev, "Execution of wmt command timed out");
	return -ETIMEDOUT;
	}

	return 0;
	}

	static int mtk_setup_fw(struct hci_dev *hdev)
	{
	const struct firmware *fw;
	const u8 *fw_ptr;
	size_t fw_size;
	int err, dlen;
	u8 flag;

	err = request_firmware(&fw, FIRMWARE_MT7622, &hdev->dev);
	if (err < 0) {
	bt_dev_err(hdev, "Failed to load firmware file (%d)", err);
	return err;
	}

	fw_ptr = fw->data;
	fw_size = fw->size;

	/* The size of patch header is 30 bytes, should be skip */
	if (fw_size < 30)
	return -EINVAL;

	fw_size -= 30;
	fw_ptr += 30;
	flag = 1;

	while (fw_size > 0) {
	dlen = min_t(int, 250, fw_size);

	/* Tell device the position in sequence */
	if (fw_size - dlen <= 0)
	flag = 3;
	else if (fw_size < fw->size - 30)
	flag = 2;

	err = mtk_hci_wmt_sync(hdev, MTK_WMT_PATCH_DWNLD, flag, dlen,
	fw_ptr);
	if (err < 0) {
	bt_dev_err(hdev, "Failed to send wmt patch dwnld (%d)",
	err);
	break;
	}

	fw_size -= dlen;
	fw_ptr += dlen;
	}

	release_firmware(fw);

	return err;
	}

	static int btmtkuart_recv_event(struct hci_dev hdev, struct sk_buff skb)
	{
	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
	struct hci_event_hdr hdr = (void )skb->data;
	int err;

	/* Fix up the vendor event id with 0xff for vendor specific instead
	* of 0xe4 so that event send via monitoring socket can be parsed
	* properly.
	*/
	if (hdr->evt == 0xe4)
	hdr->evt = HCI_EV_VENDOR;

	err = hci_recv_frame(hdev, skb);

	if (hdr->evt == HCI_EV_VENDOR) {
	if (test_and_clear_bit(BTMTKUART_TX_WAIT_VND_EVT,
	&bdev->tx_state)) {
	/* Barrier to sync with other CPUs */
	smp_mb__after_atomic();
	wake_up_bit(&bdev->tx_state, BTMTKUART_TX_WAIT_VND_EVT);
	}
	}

	return err;
	}

	static const struct h4_recv_pkt mtk_recv_pkts[] = {
	{ H4_RECV_ACL, .recv = hci_recv_frame },
	{ H4_RECV_SCO, .recv = hci_recv_frame },
	{ H4_RECV_EVENT, .recv = btmtkuart_recv_event },
	};

	static void btmtkuart_tx_work(struct work_struct *work)
	{
	struct btmtkuart_dev *bdev = container_of(work, struct btmtkuart_dev,
	tx_work);
	struct serdev_device *serdev = bdev->serdev;
	struct hci_dev *hdev = bdev->hdev;

	while (1) {
	clear_bit(BTMTKUART_TX_STATE_WAKEUP, &bdev->tx_state);

	while (1) {
	struct sk_buff *skb = skb_dequeue(&bdev->txq);
	int len;

	if (!skb)
	break;

	len = serdev_device_write_buf(serdev, skb->data,
	skb->len);
	hdev->stat.byte_tx += len;

	skb_pull(skb, len);
	if (skb->len > 0) {
	skb_queue_head(&bdev->txq, skb);
	break;
	}

	switch (hci_skb_pkt_type(skb)) {
	case HCI_COMMAND_PKT:
	hdev->stat.cmd_tx++;
	break;
	case HCI_ACLDATA_PKT:
	hdev->stat.acl_tx++;
	break;
	case HCI_SCODATA_PKT:
	hdev->stat.sco_tx++;
	break;
	}

	kfree_skb(skb);
	}

	if (!test_bit(BTMTKUART_TX_STATE_WAKEUP, &bdev->tx_state))
	break;
	}

	clear_bit(BTMTKUART_TX_STATE_ACTIVE, &bdev->tx_state);
	}

	static void btmtkuart_tx_wakeup(struct btmtkuart_dev *bdev)
	{
	if (test_and_set_bit(BTMTKUART_TX_STATE_ACTIVE, &bdev->tx_state))
	set_bit(BTMTKUART_TX_STATE_WAKEUP, &bdev->tx_state);

	schedule_work(&bdev->tx_work);
	}

	static const unsigned char *
	mtk_stp_split(struct btmtkuart_dev bdev, const unsigned char data, int count,
	int *sz_h4)
	{
	struct mtk_stp_hdr *shdr;

	/* The cursor is reset when all the data of STP is consumed out */
	if (!bdev->stp_dlen && bdev->stp_cursor >= 6)
	bdev->stp_cursor = 0;

	/* Filling pad until all STP info is obtained */
	while (bdev->stp_cursor < 6 && count > 0) {
	bdev->stp_pad[bdev->stp_cursor] = *data;
	bdev->stp_cursor++;
	data++;
	count--;
	}

	/* Retrieve STP info and have a sanity check */
	if (!bdev->stp_dlen && bdev->stp_cursor >= 6) {
	shdr = (struct mtk_stp_hdr *)&bdev->stp_pad[2];
	bdev->stp_dlen = be16_to_cpu(shdr->dlen) & 0x0fff;

	/* Resync STP when unexpected data is being read */
	if (shdr->prefix != 0x80 \|\| bdev->stp_dlen > 2048) {
	bt_dev_err(bdev->hdev, "stp format unexpect (%d, %d)",
	shdr->prefix, bdev->stp_dlen);
	bdev->stp_cursor = 2;
	bdev->stp_dlen = 0;
	}
	}

	/* Directly quit when there's no data found for H4 can process */
	if (count <= 0)
	return NULL;

	/* Tranlate to how much the size of data H4 can handle so far */
	*sz_h4 = min_t(int, count, bdev->stp_dlen);

	/* Update the remaining size of STP packet */
	bdev->stp_dlen -= *sz_h4;

	/* Data points to STP payload which can be handled by H4 */
	return data;
	}

	static int btmtkuart_recv(struct hci_dev hdev, const u8 data, size_t count)
	{
	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
	const unsigned char p_left = data, p_h4;
	int sz_left = count, sz_h4, adv;
	int err;

	while (sz_left > 0) {
	/* The serial data received from MT7622 BT controller is
	* at all time padded around with the STP header and tailer.
	*
	* A full STP packet is looking like
	* -----------------------------------
	* \| STP header \| H:4 \| STP tailer \|
	* -----------------------------------
	* but it doesn't guarantee to contain a full H:4 packet which
	* means that it's possible for multiple STP packets forms a
	* full H:4 packet that means extra STP header + length doesn't
	* indicate a full H:4 frame, things can fragment. Whose length
	* recorded in STP header just shows up the most length the
	* H:4 engine can handle currently.
	*/

	p_h4 = mtk_stp_split(bdev, p_left, sz_left, &sz_h4);
	if (!p_h4)
	break;

	adv = p_h4 - p_left;
	sz_left -= adv;
	p_left += adv;

	bdev->rx_skb = h4_recv_buf(bdev->hdev, bdev->rx_skb, p_h4,
	sz_h4, mtk_recv_pkts,
	ARRAY_SIZE(mtk_recv_pkts));
	if (IS_ERR(bdev->rx_skb)) {
	err = PTR_ERR(bdev->rx_skb);
	bt_dev_err(bdev->hdev,
	"Frame reassembly failed (%d)", err);
	bdev->rx_skb = NULL;
	return err;
	}

	sz_left -= sz_h4;
	p_left += sz_h4;
	}

	return 0;
	}

	static int btmtkuart_receive_buf(struct serdev_device serdev, const u8 data,
	size_t count)
	{
	struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev);
	int err;

	err = btmtkuart_recv(bdev->hdev, data, count);
	if (err < 0)
	return err;

	bdev->hdev->stat.byte_rx += count;

	return count;
	}

	static void btmtkuart_write_wakeup(struct serdev_device *serdev)
	{
	struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev);

	btmtkuart_tx_wakeup(bdev);
	}

	static const struct serdev_device_ops btmtkuart_client_ops = {
	.receive_buf = btmtkuart_receive_buf,
	.write_wakeup = btmtkuart_write_wakeup,
	};

	static int btmtkuart_open(struct hci_dev *hdev)
	{
	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
	struct device *dev;
	int err;

	err = serdev_device_open(bdev->serdev);
	if (err) {
	bt_dev_err(hdev, "Unable to open UART device %s",
	dev_name(&bdev->serdev->dev));
	goto err_open;
	}

	bdev->stp_cursor = 2;
	bdev->stp_dlen = 0;

	dev = &bdev->serdev->dev;

	/* Enable the power domain and clock the device requires */
	pm_runtime_enable(dev);
	err = pm_runtime_get_sync(dev);
	if (err < 0) {
	pm_runtime_put_noidle(dev);
	goto err_disable_rpm;
	}

	err = clk_prepare_enable(bdev->clk);
	if (err < 0)
	goto err_put_rpm;

	return 0;

	err_put_rpm:
	pm_runtime_put_sync(dev);
	err_disable_rpm:
	pm_runtime_disable(dev);
	err_open:
	return err;
	}

	static int btmtkuart_close(struct hci_dev *hdev)
	{
	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
	struct device *dev = &bdev->serdev->dev;

	/* Shutdown the clock and power domain the device requires */
	clk_disable_unprepare(bdev->clk);
	pm_runtime_put_sync(dev);
	pm_runtime_disable(dev);

	serdev_device_close(bdev->serdev);

	return 0;
	}

	static int btmtkuart_flush(struct hci_dev *hdev)
	{
	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);

	/* Flush any pending characters */
	serdev_device_write_flush(bdev->serdev);
	skb_queue_purge(&bdev->txq);

	cancel_work_sync(&bdev->tx_work);

	kfree_skb(bdev->rx_skb);
	bdev->rx_skb = NULL;

	bdev->stp_cursor = 2;
	bdev->stp_dlen = 0;

	return 0;
	}

	static int btmtkuart_setup(struct hci_dev *hdev)
	{
	u8 param = 0x1;
	int err = 0;

	/* Setup a firmware which the device definitely requires */
	err = mtk_setup_fw(hdev);
	if (err < 0)
	return err;

	/* Activate function the firmware providing to */
	err = mtk_hci_wmt_sync(hdev, MTK_WMT_RST, 0x4, 0, 0);
	if (err < 0) {
	bt_dev_err(hdev, "Failed to send wmt rst (%d)", err);
	return err;
	}

	/* Enable Bluetooth protocol */
	err = mtk_hci_wmt_sync(hdev, MTK_WMT_FUNC_CTRL, 0x0, sizeof(param),
	&param);
	if (err < 0) {
	bt_dev_err(hdev, "Failed to send wmt func ctrl (%d)", err);
	return err;
	}

	return 0;
	}

	static int btmtkuart_shutdown(struct hci_dev *hdev)
	{
	u8 param = 0x0;
	int err;

	/* Disable the device */
	err = mtk_hci_wmt_sync(hdev, MTK_WMT_FUNC_CTRL, 0x0, sizeof(param),
	&param);
	if (err < 0) {
	bt_dev_err(hdev, "Failed to send wmt func ctrl (%d)", err);
	return err;
	}

	return 0;
	}

	static int btmtkuart_send_frame(struct hci_dev hdev, struct sk_buff skb)
	{
	struct btmtkuart_dev *bdev = hci_get_drvdata(hdev);
	struct mtk_stp_hdr *shdr;
	int err, dlen, type = 0;

	/* Prepend skb with frame type */
	memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);

	/* Make sure that there is enough rooms for STP header and trailer */
	if (unlikely(skb_headroom(skb) < sizeof(*shdr)) \|\|
	(skb_tailroom(skb) < MTK_STP_TLR_SIZE)) {
	err = pskb_expand_head(skb, sizeof(*shdr), MTK_STP_TLR_SIZE,
	GFP_ATOMIC);
	if (err < 0)
	return err;
	}

	/* Add the STP header */
	dlen = skb->len;
	shdr = skb_push(skb, sizeof(*shdr));
	shdr->prefix = 0x80;
	shdr->dlen = cpu_to_be16((dlen & 0x0fff) \| (type << 12));
	shdr->cs = 0; /* MT7622 doesn't care about checksum value */

	/* Add the STP trailer */
	skb_put_zero(skb, MTK_STP_TLR_SIZE);

	skb_queue_tail(&bdev->txq, skb);

	btmtkuart_tx_wakeup(bdev);
	return 0;
	}

	static int btmtkuart_probe(struct serdev_device *serdev)
	{
	struct btmtkuart_dev *bdev;
	struct hci_dev *hdev;

	bdev = devm_kzalloc(&serdev->dev, sizeof(*bdev), GFP_KERNEL);
	if (!bdev)
	return -ENOMEM;

	bdev->clk = devm_clk_get(&serdev->dev, "ref");
	if (IS_ERR(bdev->clk))
	return PTR_ERR(bdev->clk);

	bdev->serdev = serdev;
	serdev_device_set_drvdata(serdev, bdev);

	serdev_device_set_client_ops(serdev, &btmtkuart_client_ops);

	INIT_WORK(&bdev->tx_work, btmtkuart_tx_work);
	skb_queue_head_init(&bdev->txq);

	/* Initialize and register HCI device */
	hdev = hci_alloc_dev();
	if (!hdev) {
	dev_err(&serdev->dev, "Can't allocate HCI device\n");
	return -ENOMEM;
	}

	bdev->hdev = hdev;

	hdev->bus = HCI_UART;
	hci_set_drvdata(hdev, bdev);

	hdev->open = btmtkuart_open;
	hdev->close = btmtkuart_close;
	hdev->flush = btmtkuart_flush;
	hdev->setup = btmtkuart_setup;
	hdev->shutdown = btmtkuart_shutdown;
	hdev->send = btmtkuart_send_frame;
	SET_HCIDEV_DEV(hdev, &serdev->dev);

	hdev->manufacturer = 70;
	set_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks);

	if (hci_register_dev(hdev) < 0) {
	dev_err(&serdev->dev, "Can't register HCI device\n");
	hci_free_dev(hdev);
	return -ENODEV;
	}

	return 0;
	}

	static void btmtkuart_remove(struct serdev_device *serdev)
	{
	struct btmtkuart_dev *bdev = serdev_device_get_drvdata(serdev);
	struct hci_dev *hdev = bdev->hdev;

	hci_unregister_dev(hdev);
	hci_free_dev(hdev);
	}

	#ifdef CONFIG_OF
	static const struct of_device_id mtk_of_match_table[] = {
	{ .compatible = "mediatek,mt7622-bluetooth"},
	{ }
	};
	MODULE_DEVICE_TABLE(of, mtk_of_match_table);
	#endif

	static struct serdev_device_driver btmtkuart_driver = {
	.probe = btmtkuart_probe,
	.remove = btmtkuart_remove,
	.driver = {
	.name = "btmtkuart",
	.of_match_table = of_match_ptr(mtk_of_match_table),
	},
	};

	module_serdev_device_driver(btmtkuart_driver);

	MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
	MODULE_DESCRIPTION("MediaTek Bluetooth Serial driver ver " VERSION);
	MODULE_VERSION(VERSION);
	MODULE_LICENSE("GPL");
	MODULE_FIRMWARE(FIRMWARE_MT7622);