// SPDX-License-Identifier: GPL-2.0-or-later

  /*
   *  Bluetooth HCI serdev driver lib
   *
   *  Copyright (C) 2017  Linaro, Ltd., Rob Herring <robh@kernel.org>
   *
   *  Based on hci_ldisc.c:
   *
   *  Copyright (C) 2000-2001  Qualcomm Incorporated
   *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
   *  Copyright (C) 2004-2005  Marcel Holtmann <marcel@holtmann.org>

   */
  
  #include <linux/kernel.h>
  #include <linux/types.h>
  #include <linux/serdev.h>
  #include <linux/skbuff.h>
  
  #include <net/bluetooth/bluetooth.h>
  #include <net/bluetooth/hci_core.h>
  
  #include "hci_uart.h"

  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 struct sk_buff *hci_uart_dequeue(struct hci_uart *hu)
  {
  	struct sk_buff *skb = hu->tx_skb;

  	if (!skb) {
  		if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
  			skb = hu->proto->dequeue(hu);
  	} else

  		hu->tx_skb = NULL;
  
  	return skb;
  }
  
  static void hci_uart_write_work(struct work_struct *work)
  {
  	struct hci_uart *hu = container_of(work, struct hci_uart, write_work);
  	struct serdev_device *serdev = hu->serdev;
  	struct hci_dev *hdev = hu->hdev;
  	struct sk_buff *skb;
  
  	/* REVISIT:
  	 * should we cope with bad skbs or ->write() returning an error value?
  	 */
  	do {
  		clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
  
  		while ((skb = hci_uart_dequeue(hu))) {
  			int len;
  
  			len = serdev_device_write_buf(serdev,
  						      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, hci_skb_pkt_type(skb));
  			kfree_skb(skb);
  		}

  	} while (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state));

  
  	clear_bit(HCI_UART_SENDING, &hu->tx_state);
  }
  
  /* ------- Interface to HCI layer ------ */

  /* Reset device */
  static int hci_uart_flush(struct hci_dev *hdev)
  {
  	struct hci_uart *hu  = hci_get_drvdata(hdev);
  
  	BT_DBG("hdev %p serdev %p", hdev, hu->serdev);
  
  	if (hu->tx_skb) {
  		kfree_skb(hu->tx_skb); hu->tx_skb = NULL;
  	}
  
  	/* Flush any pending characters in the driver and discipline. */
  	serdev_device_write_flush(hu->serdev);
  
  	if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
  		hu->proto->flush(hu);
  
  	return 0;
  }

  /* Initialize device */
  static int hci_uart_open(struct hci_dev *hdev)
  {

  	struct hci_uart *hu = hci_get_drvdata(hdev);
  	int err;

  	BT_DBG("%s %p", hdev->name, hdev);

  	/* When Quirk HCI_QUIRK_NON_PERSISTENT_SETUP is set by
  	 * driver, BT SoC is completely turned OFF during
  	 * BT OFF. Upon next BT ON UART port should be opened.
  	 */
  	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
  		err = serdev_device_open(hu->serdev);
  		if (err)
  			return err;
  		set_bit(HCI_UART_PROTO_READY, &hu->flags);
  	}

  	/* Undo clearing this from hci_uart_close() */
  	hdev->flush = hci_uart_flush;
  
  	return 0;
  }

  /* Close device */
  static int hci_uart_close(struct hci_dev *hdev)
  {

  	struct hci_uart *hu = hci_get_drvdata(hdev);

  	BT_DBG("hdev %p", hdev);

  	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags))
  		return 0;

  	hci_uart_flush(hdev);
  	hdev->flush = NULL;

  	/* When QUIRK HCI_QUIRK_NON_PERSISTENT_SETUP is set by driver,
  	 * BT SOC is completely powered OFF during BT OFF, holding port
  	 * open may drain the battery.
  	 */
  	if (test_bit(HCI_QUIRK_NON_PERSISTENT_SETUP, &hdev->quirks)) {
  		clear_bit(HCI_UART_PROTO_READY, &hu->flags);
  		serdev_device_close(hu->serdev);
  	}

  	return 0;
  }
  
  /* Send frames from HCI layer */
  static int hci_uart_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
  {
  	struct hci_uart *hu = hci_get_drvdata(hdev);
  
  	BT_DBG("%s: type %d len %d", hdev->name, hci_skb_pkt_type(skb),
  	       skb->len);
  
  	hu->proto->enqueue(hu, skb);
  
  	hci_uart_tx_wakeup(hu);
  
  	return 0;
  }
  
  static int hci_uart_setup(struct hci_dev *hdev)
  {
  	struct hci_uart *hu = hci_get_drvdata(hdev);
  	struct hci_rp_read_local_version *ver;
  	struct sk_buff *skb;
  	unsigned int speed;
  	int err;
  
  	/* Init speed if any */
  	if (hu->init_speed)
  		speed = hu->init_speed;
  	else if (hu->proto->init_speed)
  		speed = hu->proto->init_speed;
  	else
  		speed = 0;
  
  	if (speed)
  		serdev_device_set_baudrate(hu->serdev, speed);
  
  	/* Operational speed if any */
  	if (hu->oper_speed)
  		speed = hu->oper_speed;
  	else if (hu->proto->oper_speed)
  		speed = hu->proto->oper_speed;
  	else
  		speed = 0;
  
  	if (hu->proto->set_baudrate && speed) {
  		err = hu->proto->set_baudrate(hu, speed);
  		if (err)

  			bt_dev_err(hdev, "Failed to set baudrate");

  		else
  			serdev_device_set_baudrate(hu->serdev, speed);
  	}
  
  	if (hu->proto->setup)
  		return hu->proto->setup(hu);
  
  	if (!test_bit(HCI_UART_VND_DETECT, &hu->hdev_flags))
  		return 0;
  
  	skb = __hci_cmd_sync(hdev, HCI_OP_READ_LOCAL_VERSION, 0, NULL,
  			     HCI_INIT_TIMEOUT);
  	if (IS_ERR(skb)) {

  		bt_dev_err(hdev, "Reading local version info failed (%ld)",
  			   PTR_ERR(skb));

  		return 0;
  	}

  	if (skb->len != sizeof(*ver))

  		bt_dev_err(hdev, "Event length mismatch for version info");

  
  	kfree_skb(skb);
  	return 0;
  }
  
  /** hci_uart_write_wakeup - transmit buffer wakeup
   * @serdev: serial device
   *
   * This function is called by the serdev framework when it accepts
   * more data being sent.
   */
  static void hci_uart_write_wakeup(struct serdev_device *serdev)
  {
  	struct hci_uart *hu = serdev_device_get_drvdata(serdev);
  
  	BT_DBG("");
  
  	if (!hu || serdev != hu->serdev) {
  		WARN_ON(1);
  		return;
  	}
  
  	if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
  		hci_uart_tx_wakeup(hu);
  }
  
  /** hci_uart_receive_buf - receive buffer wakeup
   * @serdev: serial device
   * @data:   pointer to received data
   * @count:  count of received data in bytes
   *
   * This function is called by the serdev framework when it received data
   * in the RX buffer.
   *
   * Return: number of processed bytes
   */
  static int hci_uart_receive_buf(struct serdev_device *serdev, const u8 *data,
  				   size_t count)
  {
  	struct hci_uart *hu = serdev_device_get_drvdata(serdev);
  
  	if (!hu || serdev != hu->serdev) {
  		WARN_ON(1);
  		return 0;
  	}
  
  	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags))
  		return 0;
  
  	/* It does not need a lock here as it is already protected by a mutex in
  	 * tty caller
  	 */
  	hu->proto->recv(hu, data, count);
  
  	if (hu->hdev)
  		hu->hdev->stat.byte_rx += count;
  
  	return count;
  }

  static const struct serdev_device_ops hci_serdev_client_ops = {

  	.receive_buf = hci_uart_receive_buf,
  	.write_wakeup = hci_uart_write_wakeup,
  };
  
  int hci_uart_register_device(struct hci_uart *hu,
  			     const struct hci_uart_proto *p)
  {
  	int err;
  	struct hci_dev *hdev;
  
  	BT_DBG("");

  	serdev_device_set_client_ops(hu->serdev, &hci_serdev_client_ops);

  	err = serdev_device_open(hu->serdev);

  	if (err)
  		return err;

  	err = p->open(hu);
  	if (err)
  		goto err_open;

  	hu->proto = p;
  	set_bit(HCI_UART_PROTO_READY, &hu->flags);
  
  	/* Initialize and register HCI device */
  	hdev = hci_alloc_dev();
  	if (!hdev) {
  		BT_ERR("Can't allocate HCI device");
  		err = -ENOMEM;
  		goto err_alloc;
  	}
  
  	hu->hdev = hdev;
  
  	hdev->bus = HCI_UART;
  	hci_set_drvdata(hdev, hu);

  	INIT_WORK(&hu->init_ready, hci_uart_init_work);

  	INIT_WORK(&hu->write_work, hci_uart_write_work);

  	percpu_init_rwsem(&hu->proto_lock);

  
  	/* Only when vendor specific setup callback is provided, consider
  	 * the manufacturer information valid. This avoids filling in the
  	 * value for Ericsson when nothing is specified.
  	 */
  	if (hu->proto->setup)
  		hdev->manufacturer = hu->proto->manufacturer;
  
  	hdev->open  = hci_uart_open;
  	hdev->close = hci_uart_close;
  	hdev->flush = hci_uart_flush;
  	hdev->send  = hci_uart_send_frame;
  	hdev->setup = hci_uart_setup;
  	SET_HCIDEV_DEV(hdev, &hu->serdev->dev);
  
  	if (test_bit(HCI_UART_RAW_DEVICE, &hu->hdev_flags))
  		set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
  
  	if (test_bit(HCI_UART_EXT_CONFIG, &hu->hdev_flags))
  		set_bit(HCI_QUIRK_EXTERNAL_CONFIG, &hdev->quirks);

  	if (test_bit(HCI_UART_CREATE_AMP, &hu->hdev_flags))
  		hdev->dev_type = HCI_AMP;
  	else
  		hdev->dev_type = HCI_PRIMARY;
  
  	if (test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
  		return 0;
  
  	if (hci_register_dev(hdev) < 0) {
  		BT_ERR("Can't register HCI device");
  		err = -ENODEV;
  		goto err_register;
  	}
  
  	set_bit(HCI_UART_REGISTERED, &hu->flags);
  
  	return 0;
  
  err_register:
  	hci_free_dev(hdev);
  err_alloc:
  	clear_bit(HCI_UART_PROTO_READY, &hu->flags);
  	p->close(hu);

  err_open:
  	serdev_device_close(hu->serdev);

  	return err;
  }

  EXPORT_SYMBOL_GPL(hci_uart_register_device);

  
  void hci_uart_unregister_device(struct hci_uart *hu)
  {
  	struct hci_dev *hdev = hu->hdev;

  	cancel_work_sync(&hu->init_ready);

  	if (test_bit(HCI_UART_REGISTERED, &hu->flags))
  		hci_unregister_dev(hdev);

  	hci_free_dev(hdev);
  
  	cancel_work_sync(&hu->write_work);
  
  	hu->proto->close(hu);

  
  	if (test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
  		clear_bit(HCI_UART_PROTO_READY, &hu->flags);
  		serdev_device_close(hu->serdev);
  	}

  }
  EXPORT_SYMBOL_GPL(hci_uart_unregister_device);