/*
   *  Texas Instrument's Bluetooth Driver For Shared Transport.
   *
   *  Bluetooth Driver acts as interface between HCI core and
   *  TI Shared Transport Layer.
   *
   *  Copyright (C) 2009-2010 Texas Instruments
   *  Author: Raja Mani <raja_mani@ti.com>
   *	Pavan Savoy <pavan_savoy@ti.com>
   *
   *  This program is free software; you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License version 2 as
   *  published by the Free Software Foundation.
   *
   *  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
   *
   */
  #define DEBUG
  #include <linux/platform_device.h>
  #include <net/bluetooth/bluetooth.h>
  #include <net/bluetooth/hci_core.h>
  #include <net/bluetooth/hci.h>
  
  #include <linux/ti_wilink_st.h>
  #include <linux/module.h>
  
  /* Bluetooth Driver Version */
  #define VERSION               "1.0"
  #define MAX_BT_CHNL_IDS		3
  
  /* Number of seconds to wait for registration completion
   * when ST returns PENDING status.
   */
  #define BT_REGISTER_TIMEOUT   6000	/* 6 sec */
  
  /**
   * struct ti_st - driver operation structure
   * @hdev: hci device pointer which binds to bt driver
   * @reg_status: ST registration callback status
   * @st_write: write function provided by the ST driver
   *	to be used by the driver during send_frame.
   * @wait_reg_completion - completion sync between ti_st_open
   *	and st_reg_completion_cb.
   */
  struct ti_st {
  	struct hci_dev *hdev;
  	char reg_status;
  	long (*st_write) (struct sk_buff *);
  	struct completion wait_reg_completion;
  };
  
  /* Increments HCI counters based on pocket ID (cmd,acl,sco) */
  static inline void ti_st_tx_complete(struct ti_st *hst, int pkt_type)
  {
  	struct hci_dev *hdev = hst->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;
  	}
  }
  
  /* ------- Interfaces to Shared Transport ------ */
  
  /* Called by ST layer to indicate protocol registration completion
   * status.ti_st_open() function will wait for signal from this
   * API when st_register() function returns ST_PENDING.
   */
  static void st_reg_completion_cb(void *priv_data, char data)
  {
  	struct ti_st *lhst = priv_data;
  
  	/* Save registration status for use in ti_st_open() */
  	lhst->reg_status = data;
  	/* complete the wait in ti_st_open() */
  	complete(&lhst->wait_reg_completion);
  }
  
  /* Called by Shared Transport layer when receive data is
   * available */
  static long st_receive(void *priv_data, struct sk_buff *skb)
  {
  	struct ti_st *lhst = priv_data;
  	int err;
  
  	if (!skb)
  		return -EFAULT;
  
  	if (!lhst) {
  		kfree_skb(skb);
  		return -EFAULT;
  	}
  
  	/* Forward skb to HCI core layer */
  	err = hci_recv_frame(lhst->hdev, skb);
  	if (err < 0) {
  		BT_ERR("Unable to push skb to HCI core(%d)", err);
  		return err;
  	}
  
  	lhst->hdev->stat.byte_rx += skb->len;
  
  	return 0;
  }
  
  /* ------- Interfaces to HCI layer ------ */
  /* protocol structure registered with shared transport */
  static struct st_proto_s ti_st_proto[MAX_BT_CHNL_IDS] = {
  	{
  		.chnl_id = HCI_EVENT_PKT, /* HCI Events */
  		.hdr_len = sizeof(struct hci_event_hdr),
  		.offset_len_in_hdr = offsetof(struct hci_event_hdr, plen),
  		.len_size = 1, /* sizeof(plen) in struct hci_event_hdr */
  		.reserve = 8,
  	},
  	{
  		.chnl_id = HCI_ACLDATA_PKT, /* ACL */
  		.hdr_len = sizeof(struct hci_acl_hdr),
  		.offset_len_in_hdr = offsetof(struct hci_acl_hdr, dlen),
  		.len_size = 2,	/* sizeof(dlen) in struct hci_acl_hdr */
  		.reserve = 8,
  	},
  	{
  		.chnl_id = HCI_SCODATA_PKT, /* SCO */
  		.hdr_len = sizeof(struct hci_sco_hdr),
  		.offset_len_in_hdr = offsetof(struct hci_sco_hdr, dlen),
  		.len_size = 1, /* sizeof(dlen) in struct hci_sco_hdr */
  		.reserve = 8,
  	},
  };
  
  /* Called from HCI core to initialize the device */
  static int ti_st_open(struct hci_dev *hdev)
  {
  	unsigned long timeleft;
  	struct ti_st *hst;
  	int err, i;
  
  	BT_DBG("%s %p", hdev->name, hdev);
  
  	if (test_and_set_bit(HCI_RUNNING, &hdev->flags))
  		return -EBUSY;
  
  	/* provide contexts for callbacks from ST */
  	hst = hci_get_drvdata(hdev);
  
  	for (i = 0; i < MAX_BT_CHNL_IDS; i++) {
  		ti_st_proto[i].priv_data = hst;
  		ti_st_proto[i].max_frame_size = HCI_MAX_FRAME_SIZE;
  		ti_st_proto[i].recv = st_receive;
  		ti_st_proto[i].reg_complete_cb = st_reg_completion_cb;
  
  		/* Prepare wait-for-completion handler */
  		init_completion(&hst->wait_reg_completion);
  		/* Reset ST registration callback status flag,
  		 * this value will be updated in
  		 * st_reg_completion_cb()
  		 * function whenever it called from ST driver.
  		 */
  		hst->reg_status = -EINPROGRESS;
  
  		err = st_register(&ti_st_proto[i]);
  		if (!err)
  			goto done;
  
  		if (err != -EINPROGRESS) {
  			clear_bit(HCI_RUNNING, &hdev->flags);
  			BT_ERR("st_register failed %d", err);
  			return err;
  		}
  
  		/* ST is busy with either protocol
  		 * registration or firmware download.
  		 */
  		BT_DBG("waiting for registration "
  				"completion signal from ST");
  		timeleft = wait_for_completion_timeout
  			(&hst->wait_reg_completion,
  			 msecs_to_jiffies(BT_REGISTER_TIMEOUT));
  		if (!timeleft) {
  			clear_bit(HCI_RUNNING, &hdev->flags);
  			BT_ERR("Timeout(%d sec),didn't get reg "
  					"completion signal from ST",
  					BT_REGISTER_TIMEOUT / 1000);
  			return -ETIMEDOUT;
  		}
  
  		/* Is ST registration callback
  		 * called with ERROR status? */
  		if (hst->reg_status != 0) {
  			clear_bit(HCI_RUNNING, &hdev->flags);
  			BT_ERR("ST registration completed with invalid "
  					"status %d", hst->reg_status);
  			return -EAGAIN;
  		}
  
  done:
  		hst->st_write = ti_st_proto[i].write;
  		if (!hst->st_write) {
  			BT_ERR("undefined ST write function");
  			clear_bit(HCI_RUNNING, &hdev->flags);
  			for (i = 0; i < MAX_BT_CHNL_IDS; i++) {
  				/* Undo registration with ST */
  				err = st_unregister(&ti_st_proto[i]);
  				if (err)
  					BT_ERR("st_unregister() failed with "
  							"error %d", err);
  				hst->st_write = NULL;
  			}
  			return -EIO;
  		}
  	}
  	return 0;
  }
  
  /* Close device */
  static int ti_st_close(struct hci_dev *hdev)
  {
  	int err, i;
  	struct ti_st *hst = hci_get_drvdata(hdev);
  
  	if (!test_and_clear_bit(HCI_RUNNING, &hdev->flags))
  		return 0;
  
  	for (i = MAX_BT_CHNL_IDS-1; i >= 0; i--) {
  		err = st_unregister(&ti_st_proto[i]);
  		if (err)
  			BT_ERR("st_unregister(%d) failed with error %d",
  					ti_st_proto[i].chnl_id, err);
  	}
  
  	hst->st_write = NULL;
  
  	return err;
  }
  
  static int ti_st_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
  {
  	struct ti_st *hst;
  	long len;
  
  	if (!test_bit(HCI_RUNNING, &hdev->flags))
  		return -EBUSY;
  
  	hst = hci_get_drvdata(hdev);
  
  	/* Prepend skb with frame type */
  	memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);
  
  	BT_DBG("%s: type %d len %d", hdev->name, bt_cb(skb)->pkt_type,
  			skb->len);
  
  	/* Insert skb to shared transport layer's transmit queue.
  	 * Freeing skb memory is taken care in shared transport layer,
  	 * so don't free skb memory here.
  	 */
  	len = hst->st_write(skb);
  	if (len < 0) {
  		kfree_skb(skb);
  		BT_ERR("ST write failed (%ld)", len);
  		/* Try Again, would only fail if UART has gone bad */
  		return -EAGAIN;
  	}
  
  	/* ST accepted our skb. So, Go ahead and do rest */
  	hdev->stat.byte_tx += len;
  	ti_st_tx_complete(hst, bt_cb(skb)->pkt_type);
  
  	return 0;
  }
  
  static int bt_ti_probe(struct platform_device *pdev)
  {
  	static struct ti_st *hst;
  	struct hci_dev *hdev;
  	int err;
  
  	hst = devm_kzalloc(&pdev->dev, sizeof(struct ti_st), GFP_KERNEL);
  	if (!hst)
  		return -ENOMEM;
  
  	/* Expose "hciX" device to user space */
  	hdev = hci_alloc_dev();
  	if (!hdev)
  		return -ENOMEM;
  
  	BT_DBG("hdev %p", hdev);
  
  	hst->hdev = hdev;
  	hdev->bus = HCI_UART;
  	hci_set_drvdata(hdev, hst);
  	hdev->open = ti_st_open;
  	hdev->close = ti_st_close;
  	hdev->flush = NULL;
  	hdev->send = ti_st_send_frame;
  
  	err = hci_register_dev(hdev);
  	if (err < 0) {
  		BT_ERR("Can't register HCI device error %d", err);
  		hci_free_dev(hdev);
  		return err;
  	}
  
  	BT_DBG("HCI device registered (hdev %p)", hdev);
  
  	dev_set_drvdata(&pdev->dev, hst);
  	return err;
  }
  
  static int bt_ti_remove(struct platform_device *pdev)
  {
  	struct hci_dev *hdev;
  	struct ti_st *hst = dev_get_drvdata(&pdev->dev);
  
  	if (!hst)
  		return -EFAULT;
  
  	BT_DBG("%s", hst->hdev->name);
  
  	hdev = hst->hdev;
  	ti_st_close(hdev);
  	hci_unregister_dev(hdev);
  
  	hci_free_dev(hdev);
  
  	dev_set_drvdata(&pdev->dev, NULL);
  	return 0;
  }
  
  static struct platform_driver btwilink_driver = {
  	.probe = bt_ti_probe,
  	.remove = bt_ti_remove,
  	.driver = {
  		.name = "btwilink",
  		.owner = THIS_MODULE,
  	},
  };
  
  module_platform_driver(btwilink_driver);
  
  /* ------ Module Info ------ */
  
  MODULE_AUTHOR("Raja Mani <raja_mani@ti.com>");
  MODULE_DESCRIPTION("Bluetooth Driver for TI Shared Transport" VERSION);
  MODULE_VERSION(VERSION);
  MODULE_LICENSE("GPL");