text: /*
   *
   *  Bluetooth HCI UART driver
   *
   *  Copyright (C) 2000-2001  Qualcomm Incorporated
   *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
   *  Copyright (C) 2004-2005  Marcel Holtmann <marcel@holtmann.org>
   *
   *
   *  This program is free software; you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License as published by
   *  the Free Software Foundation; either version 2 of the License, or
   *  (at your option) any later version.
   *
   *  This program is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *  GNU General Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License
   *  along with this program; if not, write to the Free Software
   *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   *
   */
  
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/init.h>
  #include <linux/types.h>
  #include <linux/fcntl.h>
  #include <linux/interrupt.h>
  #include <linux/ptrace.h>
  #include <linux/poll.h>
  #include <linux/slab.h>
  #include <linux/tty.h>
  #include <linux/errno.h>
  #include <linux/string.h>
  #include <linux/signal.h>
  #include <linux/ioctl.h>
  #include <linux/skbuff.h>
  #include <linux/version.h>
  #include <net/bluetooth/bluetooth.h>
  #include <net/bluetooth/hci_core.h>
  
  #include "hci_uart.h"
  
  #if WOBT_NOTIFY
  #include <linux/suspend.h>
  #endif
  
  #ifdef BTCOEX
  #include "rtk_coex.h"
  #endif
  
  #define VERSION "2.2.74e8f89.20210423-153941"
  
  #if HCI_VERSION_CODE > KERNEL_VERSION(3, 4, 0)
  #define GET_DRV_DATA(x)		hci_get_drvdata(x)
  #else
  #define GET_DRV_DATA(x)		(struct hci_uart *)(x->driver_data)
  #endif
  
  #define SEMWAIT_TIMEOUT		50
  
  #if WOBT_NOTIFY
  struct hci_rsp_read_local {
  	__u8     status;
  	__u8     hci_ver;
  	__le16   hci_rev;
  	__u8     lmp_ver;
  	__le16   manufacturer;
  	__le16   lmp_subver;
  } __packed;
  #endif
  
  #if HCI_VERSION_CODE < KERNEL_VERSION(3, 4, 0)
  static int reset = 0;
  #endif
  
  static struct hci_uart_proto *hup[HCI_UART_MAX_PROTO];
  static int hci_uart_flush(struct hci_dev *hdev);
  
  int hci_uart_register_proto(struct hci_uart_proto *p)
  {
  	if (p->id >= HCI_UART_MAX_PROTO)
  		return -EINVAL;
  
  	if (hup[p->id])
  		return -EEXIST;
  
  	hup[p->id] = p;
  
  	return 0;
  }
  
  int hci_uart_unregister_proto(struct hci_uart_proto *p)
  {
  	if (p->id >= HCI_UART_MAX_PROTO)
  		return -EINVAL;
  
  	if (!hup[p->id])
  		return -EINVAL;
  
  	hup[p->id] = NULL;
  
  	return 0;
  }
  
  static struct hci_uart_proto *hci_uart_get_proto(unsigned int id)
  {
  	if (id >= HCI_UART_MAX_PROTO)
  		return NULL;
  
  	return hup[id];
  }
  
  static inline void hci_uart_tx_complete(struct hci_uart *hu, int pkt_type)
  {
  	struct hci_dev *hdev = hu->hdev;
  
  	/* Update HCI stat counters */
  	switch (pkt_type) {
  	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;
  	}
  }
  
  static inline void hci_proto_read_lock(struct hci_uart *hu)
  {
  #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 7, 0)
  	percpu_down_read(&hu->proto_lock);
  #else
  	down_read(&hu->proto_lock);
  #endif
  }
  
  static inline int hci_proto_read_trylock(struct hci_uart *hu)
  {
  #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 7, 0)
  	return percpu_down_read_trylock(&hu->proto_lock);
  #else
  	return down_read_trylock(&hu->proto_lock);
  #endif
  }
  
  static inline void hci_proto_read_unlock(struct hci_uart *hu)
  {
  #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 7, 0)
  	percpu_up_read(&hu->proto_lock);
  #else
  	up_read(&hu->proto_lock);
  #endif
  }
  
  static inline void hci_proto_write_lock(struct hci_uart *hu)
  {
  #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 7, 0)
  	percpu_down_write(&hu->proto_lock);
  #else
  	down_write(&hu->proto_lock);
  #endif
  }
  
  static inline void hci_proto_write_unlock(struct hci_uart *hu)
  {
  #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 7, 0)
  	percpu_up_write(&hu->proto_lock);
  #else
  	up_write(&hu->proto_lock);
  #endif
  }
  
  static inline int hci_proto_init_rwlock(struct hci_uart *hu)
  {
  #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 7, 0)
  	return percpu_init_rwsem(&hu->proto_lock);
  #else
  	init_rwsem(&hu->proto_lock);
  	return 0;
  #endif
  }
  
  static inline void hci_proto_free_rwlock(struct hci_uart *hu)
  {
  #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 7, 0)
  	percpu_free_rwsem(&hu->proto_lock);
  #endif
  }
  
  static inline struct sk_buff *hci_uart_dequeue(struct hci_uart *hu)
  {
  	struct sk_buff *skb = hu->tx_skb;
  
  	if (!skb) {
  		hci_proto_read_lock(hu);
  
  		if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
  			skb = hu->proto->dequeue(hu);
  
  		hci_proto_read_unlock(hu);
  	} else {
  		hu->tx_skb = NULL;
  	}
  
  	return skb;
  }
  
  /* This may be called in an IRQ context */
  int hci_uart_tx_wakeup(struct hci_uart *hu)
  {
  	/* If acquiring lock fails we assume the tty is being closed because
  	 * that is the only time the write lock is acquired. If, however,
  	 * at some point in the future the write lock is also acquired in
  	 * other situations, then this must be revisited.
  	 */
  	if (!hci_proto_read_trylock(hu))
  		return 0;
  
  	/* proto_lock is locked */
  	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags))
  		goto no_schedule;
  
  	if (in_interrupt() || in_atomic()) {
  		if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) {
  			set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
  			goto no_schedule;
  		}
  	} else {
  		/* NOTE: proto_lock can't be spin lock, because it may
  		 * schedule here. Schedule is not allowed while atomic
  		 */
  		if (down_timeout(&hu->tx_sem,
  				 msecs_to_jiffies(SEMWAIT_TIMEOUT)) == -ETIME) {
  			pr_warn("%s: Something went wrong with wait\n",
  				__func__);
  			goto no_schedule;
  		}
  		/* semaphore is locked */
  		if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) {
  			set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
  			up(&hu->tx_sem);
  			goto no_schedule;
  		}
  		up(&hu->tx_sem);
  	}
  
  	BT_DBG("");
  
  	schedule_work(&hu->write_work);
  
  no_schedule:
  	hci_proto_read_unlock(hu);
  
  	return 0;
  }
  
  static void hci_uart_write_work(struct work_struct *work)
  {
  	struct hci_uart *hu = container_of(work, struct hci_uart, write_work);
  	struct tty_struct *tty = hu->tty;
  	struct hci_dev *hdev = hu->hdev;
  	struct sk_buff *skb;
  
  	/* REVISIT: should we cope with bad skbs or ->write() returning
  	 * and error value ?
  	 */
  
   restart:
  	clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
  
  	while ((skb = hci_uart_dequeue(hu))) {
  		int len;
  
  		set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
  		len = tty->ops->write(tty, skb->data, skb->len);
  		hdev->stat.byte_tx += len;
  
  		skb_pull(skb, len);
  		if (skb->len) {
  			hu->tx_skb = skb;
  			break;
  		}
  
  		hci_uart_tx_complete(hu, bt_cb(skb)->pkt_type);
  		kfree_skb(skb);
  	}
  
  	if (down_timeout(&hu->tx_sem, msecs_to_jiffies(SEMWAIT_TIMEOUT))) {
  		pr_warn("%s: Something went wrong with wait\n", __func__);
  		goto restart;
  	}
  	/* semaphore is locked */
  	if (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state)) {
  		up(&hu->tx_sem);
  		goto restart;
  	}
  
  	clear_bit(HCI_UART_SENDING, &hu->tx_state);
  	up(&hu->tx_sem);
  	return;
  }
  
  /* ------- Interface to HCI layer ------ */
  /* Initialize device */
  static int hci_uart_open(struct hci_dev *hdev)
  {
  	BT_DBG("%s %p", hdev->name, hdev);
  
  	/* Undo clearing this from hci_uart_close() */
  	hdev->flush = hci_uart_flush;
  
  #if HCI_VERSION_CODE < KERNEL_VERSION(4, 4, 0)
  	set_bit(HCI_RUNNING, &hdev->flags);
  #endif
  
  #ifdef BTCOEX
  	rtk_btcoex_open(hdev);
  #endif
  
  	return 0;
  }
  
  /* static void hci_flush_sync(struct hci_dev *hdev)
   * {
   * #if HCI_VERSION_CODE >= KERNEL_VERSION(3, 10, 0)
   * 	u8 buf[2] = { 0, 0 };
   * 	struct sk_buff *skb;
   * 
   * 	BT_INFO("hci flush sync");
   * 
   * 	set_bit(HCI_INIT, &hdev->flags);
   * 	skb = __hci_cmd_sync(hdev, 0xfc19, 2, buf, msecs_to_jiffies(2000));
   * 	clear_bit(HCI_INIT, &hdev->flags);
   * 
   * 	if (IS_ERR(skb)) {
   * 		BT_ERR("command 0xfc19 tx failed (%ld)\n", PTR_ERR(skb));
   * 		return;
   * 	}
   * 
   * 	if (skb->len == 1)
   * 		BT_INFO("hci flush sync status %u", skb->data[0]);
   * 
   * 	kfree_skb(skb);
   * #endif
   * }
   */
  
  static int __hci_uart_flush(struct hci_dev *hdev, u8 sync)
  {
  	struct hci_uart *hu = GET_DRV_DATA(hdev);	//(struct hci_uart *) hdev->driver_data;
  	struct tty_struct *tty = hu->tty;
  
  	BT_INFO("%s: hdev %p tty %p", __func__, hdev, tty);
  
  	/* Make sure all HCI packets has been transmitted */
  	/* if (sync && test_bit(HCI_RUNNING, &hdev->flags))
  	 * 	hci_flush_sync(hdev);
  	 */
  
  	if (hu->tx_skb) {
  		kfree_skb(hu->tx_skb);
  		hu->tx_skb = NULL;
  	}
  
  	/* Flush any pending characters in the driver and discipline. */
  	/* tty_ldisc_flush(tty);
  	 * tty_driver_flush_buffer(tty);
  	 */
  	/* Don't flush the tty. Sometime, the hdev is closed abnormally.
  	 * There may be cmd complete event in rx buf or the sent ack in tx buf.
  	 * tty flush will result in hciX: command 0xXXXX tx timeout
  	 */
  	tty_wait_until_sent(tty, msecs_to_jiffies(500));
  
  	hci_proto_read_lock(hu);
  
  	if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
  		hu->proto->flush(hu);
  
  	hci_proto_read_unlock(hu);
  
  	return 0;
  }
  
  /* Reset device */
  static int hci_uart_flush(struct hci_dev *hdev)
  {
  	return __hci_uart_flush(hdev, 1);
  }
  
  /* Close device */
  static int hci_uart_close(struct hci_dev *hdev)
  {
  	BT_INFO("%s: hdev %p", __func__, hdev);
  
  	/* When in kernel 4.4.0 and greater, the HCI_RUNNING bit is
  	 * cleared in hci_dev_do_close(). */
  #if HCI_VERSION_CODE < KERNEL_VERSION(4, 4, 0)
  	if (!test_and_clear_bit(HCI_RUNNING, &hdev->flags))
  		return 0;
  #else
  	if (test_bit(HCI_RUNNING, &hdev->flags))
  		BT_ERR("HCI_RUNNING is not cleared before.");
  #endif
  
  	if (test_bit(HCI_RUNNING, &hdev->flags))
  		__hci_uart_flush(hdev, 0);
  	else
  		__hci_uart_flush(hdev, 1);
  
  	hdev->flush = NULL;
  
  #ifdef BTCOEX
  	rtk_btcoex_close();
  #endif
  
  	return 0;
  }
  
  /* Send frames from HCI layer */
  #if HCI_VERSION_CODE < KERNEL_VERSION(3, 13, 0)
  int hci_uart_send_frame(struct sk_buff *skb)
  #else
  int hci_uart_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
  #endif
  {
  #if HCI_VERSION_CODE < KERNEL_VERSION(3, 13, 0)
  	struct hci_dev *hdev = (struct hci_dev *)skb->dev;
  #endif
  	struct hci_uart *hu;
  
  	if (!hdev) {
  		BT_ERR("Frame for unknown device (hdev=NULL)");
  		return -ENODEV;
  	}
  
  #if HCI_VERSION_CODE < KERNEL_VERSION(4, 4, 0)
  	if (!test_bit(HCI_RUNNING, &hdev->flags))
  		return -EBUSY;
  #endif
  
  	hu = GET_DRV_DATA(hdev);	//(struct hci_uart *) hdev->driver_data;
  
  	BT_DBG("%s: type %d len %d", hdev->name, bt_cb(skb)->pkt_type,
  	       skb->len);
  
  #ifdef BTCOEX
  	if (bt_cb(skb)->pkt_type == HCI_COMMAND_PKT)
  		rtk_btcoex_parse_cmd(skb->data, skb->len);
  	if (bt_cb(skb)->pkt_type == HCI_ACLDATA_PKT)
  		rtk_btcoex_parse_l2cap_data_tx(skb->data, skb->len);
  #endif
  
  	hci_proto_read_lock(hu);
  
  	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
  		hci_proto_read_unlock(hu);
  		return -EUNATCH;
  	}
  
  	hu->proto->enqueue(hu, skb);
  	hci_proto_read_unlock(hu);
  
  	hci_uart_tx_wakeup(hu);
  
  	return 0;
  }
  
  #if HCI_VERSION_CODE < KERNEL_VERSION(3, 4, 0)
  static void hci_uart_destruct(struct hci_dev *hdev)
  {
  	if (!hdev)
  		return;
  
  	BT_DBG("%s", hdev->name);
  	kfree(hdev->driver_data);
  }
  #endif
  
  #if WOBT_NOTIFY
  static int hci_uart_async_send(struct hci_uart *hu, u16 opcode,
  			       u32 plen, const void *param)
  {
  	int len = HCI_COMMAND_HDR_SIZE + plen;
  	struct hci_command_hdr *hdr;
  	struct sk_buff *skb;
  
  	skb = bt_skb_alloc(len, GFP_ATOMIC);
  	if (!skb)
  		return -ENOMEM;
  
  	hdr = (struct hci_command_hdr *)skb_put(skb, HCI_COMMAND_HDR_SIZE);
  	hdr->opcode = cpu_to_le16(opcode);
  	hdr->plen   = plen;
  
  	if (plen)
  		memcpy(skb_put(skb, plen), param, plen);
  
  	BT_INFO("rtl: skb len %d", skb->len);
  
  	bt_cb(skb)->pkt_type = HCI_COMMAND_PKT;
  
  #if HCI_VERSION_CODE >= KERNEL_VERSION(3, 18, 0)
  #if HCI_VERSION_CODE < KERNEL_VERSION(4, 4, 0)
  	bt_cb(skb)->opcode = opcode;
  #else
  	bt_cb(skb)->hci.opcode = opcode;
  #endif
  #endif
  
  	/* Stand-alone HCI commands must be flagged as
  	 * single-command requests.
  	 */
  #if HCI_VERSION_CODE >= KERNEL_VERSION(3, 10, 0)
  #if HCI_VERSION_CODE < KERNEL_VERSION(4, 4, 0)
  	bt_cb(skb)->req.start = true;
  #else
  
  #if HCI_VERSION_CODE < KERNEL_VERSION(4, 5, 0)
  	bt_cb(skb)->hci.req_start = true;
  #else
  
  	bt_cb(skb)->hci.req_flags |= HCI_REQ_START;
  #endif
  #endif /* 4.4.0 */
  #endif /* 3.10.0 */
  
  #if HCI_VERSION_CODE < KERNEL_VERSION(3, 13, 0)
  	hci_uart_send_frame(skb);
  #else
  	hci_uart_send_frame(hu->hdev, skb);
  #endif
  
  	/* hci_proto_read_lock(hu);
  
  	 * if (!test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
  	 * 	hci_proto_read_unlock(hu);
  	 * 	BT_ERR("rtl send: proto not ready");
  	 * 	return -EUNATCH;
  	 * }
  
  	 * hu->proto->enqueue(hu, skb);
  	 * hci_proto_read_unlock(hu);
  
  	 * hci_uart_tx_wakeup(hu);
  	 */
  
  	return 0;
  }
  
  static int rtl_read_local_version(struct hci_dev *hdev, u8 *hci_ver,
  				  u16 *hci_rev, u16 *lmp_subver)
  {
  	struct hci_rsp_read_local *ver;
  	struct sk_buff *skb;
  
  	skb = __hci_cmd_sync(hdev, 0x1001, 0, NULL, HCI_INIT_TIMEOUT);
  	if (IS_ERR(skb)) {
  		BT_ERR("rtl: Could not read lmp subversion");
  		return PTR_ERR(skb);
  	}
  
  	if (skb->len != sizeof(struct hci_rsp_read_local)) {
  		BT_ERR("%s: rtl: Local version length mismatch", hdev->name);
  		kfree_skb(skb);
  		return -EIO;
  	}
  
  	ver = (struct hci_rsp_read_local *)skb->data;
  	*hci_ver = ver->hci_ver;
  	*hci_rev = le16_to_cpu(ver->hci_rev);
  	*lmp_subver = le16_to_cpu(ver->lmp_subver);
  
  	kfree_skb(skb);
  
  	return 0;
  }
  
  #if RTKBT_TV_POWERON_WHITELIST
  static int rtkbt_lookup_le_device_poweron_whitelist(struct hci_dev *hdev)
  {
  	struct hci_conn_params *p;
  	u8 *params;
  	int result = 0;
  	struct sk_buff *skb;
  
  	hci_dev_lock(hdev);
  	list_for_each_entry(p, &hdev->le_conn_params, list) {
  #if 0 // for debug message
  		BT_INFO("%s(): auto_connect = %d", __FUNCTION__, p->auto_connect);
  		BT_INFO("%s(): addr_type = 0x%02x", __FUNCTION__, p->addr_type);
  		BT_INFO("%s(): addr=%02x:%02x:%02x:%02x:%02x:%02x", __FUNCTION__,
                                  p->addr.b[5], p->addr.b[4], p->addr.b[3],
                                  p->addr.b[2], p->addr.b[1], p->addr.b[0]);
  #endif
  		if ( p->auto_connect == HCI_AUTO_CONN_ALWAYS &&
  			p->addr_type == ADDR_LE_DEV_PUBLIC ) {
  
  			BT_INFO("%s(): Set RTKBT LE Power-on Whitelist for "
  				"%02x:%02x:%02x:%02x:%02x:%02x", __FUNCTION__,
                                  p->addr.b[5], p->addr.b[4], p->addr.b[3],
                                  p->addr.b[2], p->addr.b[1], p->addr.b[0]);
  
  			params = kzalloc(8, GFP_ATOMIC);
  			if (!params) {
  				BT_ERR("Can't allocate memory for params");
  				return -ENOMEM;
  			}
  
  			params[0] = 0x00;
  			params[1] = p->addr.b[0];
  			params[2] = p->addr.b[1];
  			params[3] = p->addr.b[2];
  			params[4] = p->addr.b[3];
  			params[5] = p->addr.b[4];
  			params[6] = p->addr.b[5];
  
  			skb = __hci_cmd_sync(hdev, 0xfc7b, 7, params, HCI_INIT_TIMEOUT);
  			if (IS_ERR(skb)) {
  				BT_ERR("rtl: Command failed for power-on whitelist");
  				return PTR_ERR(skb);
  			}
  
  			kfree(params);
  			kfree_skb(skb);
  		}
  	}
  	hci_dev_unlock(hdev);
  
  	return result;
  }
  #endif
  
  static int hci_uart_pm_notifier(struct notifier_block *b, unsigned long v, void *d)
  {
  	int result;
  	struct hci_uart *hu = container_of(b, struct hci_uart, pm_notify_block);
  	u8 hci_ver = 0;
  	u16 hci_rev = 0;
  	u16 lmp_subver = 0;
  #if WOBT_NOTIFY_BG_SCAN_LE_WHITELIST_ONLY
  	u8 params_bg_scan[5] = { 0x60, 0x01, 0x10, 0x00, 0x01 };
  #endif
  	u8 params_suspend_notify[1] = { 0x01 };
  
  	BT_INFO("%s: %lu", __func__, v);
  	switch (v) {
  	case PM_SUSPEND_PREPARE:
  		BT_INFO("rtl: bt suspending");
  #if WOBT_NOTIFY_BG_SCAN_LE_WHITELIST_ONLY
  		/* Send set back ground scan parameters to Controller for power-on mode */
  		result = hci_uart_async_send(hu, 0xfc7a, 5, params_bg_scan);
  		if (result)
  			BT_ERR("Realtek bg-scan h5-bt failed");
  		/* FIXME: Ensure the above vendor command is sent to Controller
  		 * and we received the h5 ack from Controller
  		 * */
  		 msleep(500);
  
  #endif
  
  #if RTKBT_TV_POWERON_WHITELIST
  		result = rtkbt_lookup_le_device_poweron_whitelist(hu->hdev);
  		if (result < 0) {
  			BT_ERR("rtkbt_lookup_le_device_poweron_whitelist error: %d", result);
  		}
  #endif
  
  		/* Send host sleep notification to Controller */
  		/* skb = __hci_cmd_sync(hu->hdev, 0xfc28, 1, &param,
  		 * 		     HCI_INIT_TIMEOUT);
  		 * if (IS_ERR(skb)) {
  		 * 	BT_ERR("Realtek Suspend h5-bt failed");
  		 * 	goto done;
  		 * }
  		 * kfree_skb(skb);
  		 */
  		result = hci_uart_async_send(hu, 0xfc28, 1, params_suspend_notify);
  		if (result)
  			BT_ERR("Realtek suspend h5-bt failed");
  
  		/* FIXME: Ensure the above vendor command is sent to Controller
  		 * and we received the h5 ack from Controller
  		 * */
  		msleep(500);
  
  		break;
  	case PM_POST_SUSPEND:
  		result = rtl_read_local_version(hu->hdev, &hci_ver, &hci_rev,
  						&lmp_subver);
  		if (result)
  			break;
  		BT_INFO("rtl resume: hci ver %u, hci rev %04x, lmp subver %04x",
  			hci_ver, hci_rev, lmp_subver);
  		break;
  	default:
  		BT_INFO("Caught msg %lu other than SUSPEND_PREPARE", v);
  		break;
  	}
  
  	return 0;
  }
  #endif
  
  /* ------ LDISC part ------ */
  /* hci_uart_tty_open
   *
   * Called when line discipline changed to HCI_UART.
   *
   * Arguments:
   *     tty    pointer to tty info structure
   * Return Value:
   *     0 if success, otherwise error code
   */
  static int hci_uart_tty_open(struct tty_struct *tty)
  {
  	struct hci_uart *hu = (void *)tty->disc_data;
  
  	BT_DBG("tty %p", tty);
  
  	/* But nothing ensures disc_data to be NULL. And since ld->ops->open
  	 * shall be called only once, we do not need the check at all.
  	 * So remove it.
  	 *
  	 * Note that this is not an issue now, but n_tty will start using the
  	 * disc_data pointer and this invalid 'if' would trigger then rendering
  	 * TTYs over BT unusable.
  	 */
  #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 8, 0)
  	/* FIXME: This btw is bogus, nothing requires the old ldisc to clear
  	 * the pointer
  	 */
  	if (hu)
  		return -EEXIST;
  #endif
  
  	/* Error if the tty has no write op instead of leaving an exploitable
  	 * hole
  	 */
  	if (tty->ops->write == NULL)
  		return -EOPNOTSUPP;
  
  	if (!(hu = kzalloc(sizeof(struct hci_uart), GFP_KERNEL))) {
  		BT_ERR("Can't allocate control structure");
  		return -ENFILE;
  	}
  
  	tty->disc_data = hu;
  	hu->tty = tty;
  	tty->receive_room = 65536;
  
  	INIT_WORK(&hu->write_work, hci_uart_write_work);
  
  	hci_proto_init_rwlock(hu);
  	sema_init(&hu->tx_sem, 1);
  
  	/* Flush any pending characters in the driver and line discipline. */
  
  	/* FIXME: why is this needed. Note don't use ldisc_ref here as the
  	   open path is before the ldisc is referencable */
  
  	if (tty->ldisc->ops->flush_buffer)
  		tty->ldisc->ops->flush_buffer(tty);
  	tty_driver_flush_buffer(tty);
  
  #if WOBT_NOTIFY
  	hu->pm_notify_block.notifier_call = hci_uart_pm_notifier;
  	register_pm_notifier(&hu->pm_notify_block);
  #endif
  
  	return 0;
  }
  
  /* hci_uart_tty_close()
   *
   * Called when the line discipline is changed to something
   * else, the tty is closed, or the tty detects a hangup.
   */
  static void hci_uart_tty_close(struct tty_struct *tty)
  {
  	struct hci_uart *hu = (void *)tty->disc_data;
  	struct hci_dev *hdev;
  
  	BT_INFO("%s: tty %p", __func__, tty);
  
  	/* Detach from the tty */
  	tty->disc_data = NULL;
  
  	if (!hu)
  		return;
  
  	hdev = hu->hdev;
  	if (hdev)
  		hci_uart_close(hdev);
  
  	if (test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
  		hci_proto_write_lock(hu);
  		clear_bit(HCI_UART_PROTO_READY, &hu->flags);
  		hci_proto_write_unlock(hu);
  
  		cancel_work_sync(&hu->write_work);
  
  		if (hdev) {
  			if (test_bit(HCI_UART_REGISTERED, &hu->flags))
  				hci_unregister_dev(hdev);
  			hci_free_dev(hdev);
  		}
  		hu->proto->close(hu);
  	}
  	clear_bit(HCI_UART_PROTO_SET, &hu->flags);
  
  	hci_proto_free_rwlock(hu);
  #if WOBT_NOTIFY
  	unregister_pm_notifier(&hu->pm_notify_block);
  #endif
  
  	kfree(hu);
  }
  
  /* hci_uart_tty_wakeup()
   *
   * Callback for transmit wakeup. Called when low level
   * device driver can accept more send data.
   *
   * Arguments:        tty    pointer to associated tty instance data
   * Return Value:    None
   */
  static void hci_uart_tty_wakeup(struct tty_struct *tty)
  {
  	struct hci_uart *hu = (void *)tty->disc_data;
  
  	BT_DBG("");
  
  	if (!hu)
  		return;
  
  	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
  
  	if (tty != hu->tty)
  		return;
  
  	if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
  		hci_uart_tx_wakeup(hu);
  }
  
  /* hci_uart_tty_receive()
   *
   * Called by tty low level driver when receive data is
   * available.
   *
   * Arguments:  tty          pointer to tty isntance data
   *             data         pointer to received data
   *             flags        pointer to flags for data
   *             count        count of received data in bytes
   *
   * Return Value:    None
   */
  static void hci_uart_tty_receive(struct tty_struct *tty, const u8 * data,
  				 char *flags, int count)
  {
  	struct hci_uart *hu = (void *)tty->disc_data;
  	int (*proto_receive)(struct hci_uart *hu, void *data, int len);
  
  	if (!hu || tty != hu->tty)
  		return;
  
  	hci_proto_read_lock(hu);
  
  	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
  		hci_proto_read_unlock(hu);
  		return;
  	}
  
  	proto_receive = hu->proto->recv;
  #if LINUX_VERSION_CODE < KERNEL_VERSION(4, 0, 0)
  	proto_receive(hu, (void *)data, count);
  	hci_proto_read_unlock(hu);
  #else
  	hci_proto_read_unlock(hu);
  	/* It does not need a lock here as it is already protected by a mutex in
  	 * tty caller
  	 */
  	proto_receive(hu, (void *)data, count);
  #endif
  
  	if (hu->hdev)
  		hu->hdev->stat.byte_rx += count;
  
  	tty_unthrottle(tty);
  }
  
  static int hci_uart_register_dev(struct hci_uart *hu)
  {
  	struct hci_dev *hdev;
  
  	BT_INFO("hci_uart_register_dev");
  
  	/* Initialize and register HCI device */
  	hdev = hci_alloc_dev();
  	if (!hdev) {
  		BT_ERR("Can't allocate HCI device");
  		return -ENOMEM;
  	}
  
  	hu->hdev = hdev;
  
  #if HCI_VERSION_CODE > KERNEL_VERSION(2, 6, 33)
  	hdev->bus = HCI_UART;
  #else
  	hdev->type = HCI_UART;
  #endif
  
  #if HCI_VERSION_CODE >= KERNEL_VERSION(3, 4, 0)
  	hci_set_drvdata(hdev, hu);
  #else
  	hdev->driver_data = hu;
  #endif
  
  	hdev->open = hci_uart_open;
  	hdev->close = hci_uart_close;
  	hdev->flush = hci_uart_flush;
  	hdev->send = hci_uart_send_frame;
  
  	/* NOTE: No hdev->setup setting for Realtek BTUART because
  	 * the download procedure is done with rtk_hciattach in userspace
  	 * before this function called in hci_uart_set_proto()
  	 */
  
  	SET_HCIDEV_DEV(hdev, hu->tty->dev);
  
  #if HCI_VERSION_CODE < KERNEL_VERSION(3, 4, 0)
  	hdev->destruct = hci_uart_destruct;
  	hdev->owner = THIS_MODULE;
  #endif
  
  #if HCI_VERSION_CODE < KERNEL_VERSION(3, 4, 0)
  	if (!reset)
  		set_bit(HCI_QUIRK_NO_RESET, &hdev->quirks);
  #endif
  
  #if HCI_VERSION_CODE >= KERNEL_VERSION(2, 6, 36)
  	if (test_bit(HCI_UART_RAW_DEVICE, &hu->hdev_flags))
  		set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
  #endif
  
  #if HCI_VERSION_CODE >= KERNEL_VERSION(3, 17, 0)
  	if (test_bit(HCI_UART_EXT_CONFIG, &hu->hdev_flags))
  		set_bit(HCI_QUIRK_EXTERNAL_CONFIG, &hdev->quirks);
  #endif
  
  #if HCI_VERSION_CODE >= KERNEL_VERSION(3, 4, 0)
  	if (!test_bit(HCI_UART_RESET_ON_INIT, &hu->hdev_flags))
  #if HCI_VERSION_CODE >= KERNEL_VERSION(3, 6, 0)
  		set_bit(HCI_QUIRK_RESET_ON_CLOSE, &hdev->quirks);
  #else
  		set_bit(HCI_QUIRK_NO_RESET, &hdev->quirks);
  #endif
  #endif
  
  #if HCI_VERSION_CODE >= KERNEL_VERSION(3, 4, 0)
  	if (test_bit(HCI_UART_CREATE_AMP, &hu->hdev_flags))
  		hdev->dev_type = HCI_AMP;
  	else
  #if HCI_VERSION_CODE < KERNEL_VERSION(4, 8, 0)
  		hdev->dev_type = HCI_BREDR;
  #else
  		hdev->dev_type = HCI_PRIMARY;
  #endif
  #endif
  
  #if HCI_VERSION_CODE >= KERNEL_VERSION(4, 1, 0)
  	set_bit(HCI_QUIRK_SIMULTANEOUS_DISCOVERY, &hdev->quirks);
  #endif
  
  	if (hci_register_dev(hdev) < 0) {
  		BT_ERR("Can't register HCI device");
  		hci_free_dev(hdev);
  		return -ENODEV;
  	}
  
  	set_bit(HCI_UART_REGISTERED, &hu->flags);
  
  #ifdef BTCOEX
  	rtk_btcoex_probe(hdev);
  #endif
  
  	return 0;
  }
  
  static int hci_uart_set_proto(struct hci_uart *hu, int id)
  {
  	struct hci_uart_proto *p;
  	int err;
  
  	p = hci_uart_get_proto(id);
  	if (!p)
  		return -EPROTONOSUPPORT;
  
  	err = p->open(hu);
  	if (err)
  		return err;
  
  	hu->proto = p;
  	set_bit(HCI_UART_PROTO_READY, &hu->flags);
  
  	/* Initialize and register HCI dev */
  	err = hci_uart_register_dev(hu);
  	if (err) {
  		clear_bit(HCI_UART_PROTO_READY, &hu->flags);
  		p->close(hu);
  		return err;
  	}
  
  	return 0;
  }
  
  #if HCI_VERSION_CODE >= KERNEL_VERSION(3, 17, 0)
  static int hci_uart_set_flags(struct hci_uart *hu, unsigned long flags)
  {
  	/* TODO: Add HCI_UART_INIT_PENDING, HCI_UART_VND_DETECT check  */
  	unsigned long valid_flags = BIT(HCI_UART_RAW_DEVICE) |
  				    BIT(HCI_UART_RESET_ON_INIT) |
  				    BIT(HCI_UART_CREATE_AMP) |
  				    BIT(HCI_UART_EXT_CONFIG);
  
  	if (flags & ~valid_flags)
  		return -EINVAL;
  
  	hu->hdev_flags = flags;
  
  	return 0;
  }
  #endif
  
  /* hci_uart_tty_ioctl()
   *
   *    Process IOCTL system call for the tty device.
   *
   * Arguments:
   *
   *    tty        pointer to tty instance data
   *    file       pointer to open file object for device
   *    cmd        IOCTL command code
   *    arg        argument for IOCTL call (cmd dependent)
   *
   * Return Value:    Command dependent
   */
  static int hci_uart_tty_ioctl(struct tty_struct *tty, struct file *file,
  			      unsigned int cmd, unsigned long arg)
  {
  	struct hci_uart *hu = (void *)tty->disc_data;
  	int err = 0;
  
  	BT_DBG("");
  
  	/* Verify the status of the device */
  	if (!hu)
  		return -EBADF;
  
  	switch (cmd) {
  	case HCIUARTSETPROTO:
  		if (!test_and_set_bit(HCI_UART_PROTO_SET, &hu->flags)) {
  			err = hci_uart_set_proto(hu, arg);
  			if (err) {
  				clear_bit(HCI_UART_PROTO_SET, &hu->flags);
  				return err;
  			}
  		} else
  			return -EBUSY;
  		break;
  
  	case HCIUARTGETPROTO:
  		if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
  			return hu->proto->id;
  		return -EUNATCH;
  
  	case HCIUARTGETDEVICE:
  		if (test_bit(HCI_UART_REGISTERED, &hu->flags))
  			return hu->hdev->id;
  		return -EUNATCH;
  
  	case HCIUARTSETFLAGS:
  		if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
  			return -EBUSY;
  #if HCI_VERSION_CODE >= KERNEL_VERSION(3, 17, 0)
  		err = hci_uart_set_flags(hu, arg);
  		if (err)
  			return err;
  #else
  		hu->hdev_flags = arg;
  #endif
  		break;
  
  	case HCIUARTGETFLAGS:
  		return hu->hdev_flags;
  
  	default:
  		err = n_tty_ioctl_helper(tty, file, cmd, arg);
  		break;
  	};
  
  	return err;
  }
  
  /*
   * We don't provide read/write/poll interface for user space.
   */
  static ssize_t hci_uart_tty_read(struct tty_struct *tty, struct file *file,
  				 unsigned char __user * buf, size_t nr)
  {
  	return 0;
  }
  
  static ssize_t hci_uart_tty_write(struct tty_struct *tty, struct file *file,
  				  const unsigned char *data, size_t count)
  {
  	return 0;
  }
  
  static unsigned int hci_uart_tty_poll(struct tty_struct *tty,
  				      struct file *filp, poll_table * wait)
  {
  	return 0;
  }
  
  static int __init hci_uart_init(void)
  {
  	static struct tty_ldisc_ops hci_uart_ldisc;
  	int err;
  
  	BT_INFO("HCI UART driver ver %s", VERSION);
  
  	/* Register the tty discipline */
  
  	memset(&hci_uart_ldisc, 0, sizeof(hci_uart_ldisc));
  	hci_uart_ldisc.magic = TTY_LDISC_MAGIC;
  	hci_uart_ldisc.name = "n_hci";
  	hci_uart_ldisc.open = hci_uart_tty_open;
  	hci_uart_ldisc.close = hci_uart_tty_close;
  	hci_uart_ldisc.read = hci_uart_tty_read;
  	hci_uart_ldisc.write = hci_uart_tty_write;
  	hci_uart_ldisc.ioctl = hci_uart_tty_ioctl;
  	hci_uart_ldisc.poll = hci_uart_tty_poll;
  	hci_uart_ldisc.receive_buf = hci_uart_tty_receive;
  	hci_uart_ldisc.write_wakeup = hci_uart_tty_wakeup;
  	hci_uart_ldisc.owner = THIS_MODULE;
  
  	if ((err = tty_register_ldisc(N_HCI, &hci_uart_ldisc))) {
  		BT_ERR("HCI line discipline registration failed. (%d)", err);
  		return err;
  	}
  #ifdef CONFIG_BT_HCIUART_H4
  	h4_init();
  #endif
  	/* Add realtek h5 support */
  	h5_init();
  
  #ifdef BTCOEX
  	rtk_btcoex_init();
  #endif
  
  	return 0;
  }
  
  static void __exit hci_uart_exit(void)
  {
  	int err;
  
  #ifdef CONFIG_BT_HCIUART_H4
  	h4_deinit();
  #endif
  	h5_deinit();
  
  	/* Release tty registration of line discipline */
  	if ((err = tty_unregister_ldisc(N_HCI)))
  		BT_ERR("Can't unregister HCI line discipline (%d)", err);
  
  #ifdef BTCOEX
  	rtk_btcoex_exit();
  #endif
  }
  
  module_init(hci_uart_init);
  module_exit(hci_uart_exit);
  
  #if HCI_VERSION_CODE < KERNEL_VERSION(3, 4, 0)
  module_param(reset, bool, 0644);
  MODULE_PARM_DESC(reset, "Send HCI reset command on initialization");
  #endif
  
  MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
  MODULE_DESCRIPTION("Bluetooth HCI UART driver ver " VERSION);
  MODULE_VERSION(VERSION);
  MODULE_LICENSE("GPL");
  MODULE_ALIAS_LDISC(N_HCI);
  