/*
   * Copyright (C) 2011 Instituto Nokia de Tecnologia
   *
   * Authors:
   *    Lauro Ramos Venancio <lauro.venancio@openbossa.org>
   *    Aloisio Almeida Jr <aloisio.almeida@openbossa.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, see <http://www.gnu.org/licenses/>.

   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__

  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/slab.h>

  #include <linux/rfkill.h>

  #include <linux/nfc.h>

  #include <net/genetlink.h>

  #include "nfc.h"
  
  #define VERSION "0.1"

  #define NFC_CHECK_PRES_FREQ_MS	2000

  int nfc_devlist_generation;
  DEFINE_MUTEX(nfc_devlist_mutex);

  /* NFC device ID bitmap */
  static DEFINE_IDA(nfc_index_ida);

  int nfc_fw_download(struct nfc_dev *dev, const char *firmware_name)

  {
  	int rc = 0;
  
  	pr_debug("%s do firmware %s
  ", dev_name(&dev->dev), firmware_name);
  
  	device_lock(&dev->dev);
  
  	if (!device_is_registered(&dev->dev)) {
  		rc = -ENODEV;
  		goto error;
  	}
  
  	if (dev->dev_up) {
  		rc = -EBUSY;
  		goto error;
  	}

  	if (!dev->ops->fw_download) {

  		rc = -EOPNOTSUPP;
  		goto error;
  	}

  	dev->fw_download_in_progress = true;
  	rc = dev->ops->fw_download(dev, firmware_name);

  	if (rc)

  		dev->fw_download_in_progress = false;

  
  error:
  	device_unlock(&dev->dev);
  	return rc;
  }

  /**
   * nfc_fw_download_done - inform that a firmware download was completed
   *
   * @dev: The nfc device to which firmware was downloaded
   * @firmware_name: The firmware filename
   * @result: The positive value of a standard errno value
   */
  int nfc_fw_download_done(struct nfc_dev *dev, const char *firmware_name,
  			 u32 result)

  {

  	dev->fw_download_in_progress = false;

  	return nfc_genl_fw_download_done(dev, firmware_name, result);

  }

  EXPORT_SYMBOL(nfc_fw_download_done);

  /**

   * nfc_dev_up - turn on the NFC device
   *
   * @dev: The nfc device to be turned on
   *
   * The device remains up until the nfc_dev_down function is called.
   */
  int nfc_dev_up(struct nfc_dev *dev)
  {
  	int rc = 0;

  	pr_debug("dev_name=%s
  ", dev_name(&dev->dev));

  
  	device_lock(&dev->dev);

  	if (dev->rfkill && rfkill_blocked(dev->rfkill)) {
  		rc = -ERFKILL;
  		goto error;
  	}

  	if (!device_is_registered(&dev->dev)) {
  		rc = -ENODEV;
  		goto error;
  	}

  	if (dev->fw_download_in_progress) {

  		rc = -EBUSY;
  		goto error;
  	}

  	if (dev->dev_up) {
  		rc = -EALREADY;
  		goto error;
  	}
  
  	if (dev->ops->dev_up)
  		rc = dev->ops->dev_up(dev);
  
  	if (!rc)
  		dev->dev_up = true;

  	/* We have to enable the device before discovering SEs */

  	if (dev->ops->discover_se && dev->ops->discover_se(dev))
  		pr_err("SE discovery failed
  ");

  error:
  	device_unlock(&dev->dev);
  	return rc;
  }
  
  /**
   * nfc_dev_down - turn off the NFC device
   *
   * @dev: The nfc device to be turned off
   */
  int nfc_dev_down(struct nfc_dev *dev)
  {
  	int rc = 0;

  	pr_debug("dev_name=%s
  ", dev_name(&dev->dev));

  
  	device_lock(&dev->dev);
  
  	if (!device_is_registered(&dev->dev)) {
  		rc = -ENODEV;
  		goto error;
  	}
  
  	if (!dev->dev_up) {
  		rc = -EALREADY;
  		goto error;
  	}

  	if (dev->polling || dev->active_target) {

  		rc = -EBUSY;
  		goto error;
  	}
  
  	if (dev->ops->dev_down)
  		dev->ops->dev_down(dev);
  
  	dev->dev_up = false;
  
  error:
  	device_unlock(&dev->dev);
  	return rc;
  }

  static int nfc_rfkill_set_block(void *data, bool blocked)
  {
  	struct nfc_dev *dev = data;
  
  	pr_debug("%s blocked %d", dev_name(&dev->dev), blocked);
  
  	if (!blocked)
  		return 0;
  
  	nfc_dev_down(dev);
  
  	return 0;
  }
  
  static const struct rfkill_ops nfc_rfkill_ops = {
  	.set_block = nfc_rfkill_set_block,
  };

  /**

   * nfc_start_poll - start polling for nfc targets
   *
   * @dev: The nfc device that must start polling
   * @protocols: bitset of nfc protocols that must be used for polling
   *
   * The device remains polling for targets until a target is found or
   * the nfc_stop_poll function is called.
   */

  int nfc_start_poll(struct nfc_dev *dev, u32 im_protocols, u32 tm_protocols)

  {
  	int rc;

  	pr_debug("dev_name %s initiator protocols 0x%x target protocols 0x%x
  ",
  		 dev_name(&dev->dev), im_protocols, tm_protocols);

  	if (!im_protocols && !tm_protocols)

  		return -EINVAL;
  
  	device_lock(&dev->dev);
  
  	if (!device_is_registered(&dev->dev)) {
  		rc = -ENODEV;
  		goto error;
  	}

  	if (!dev->dev_up) {
  		rc = -ENODEV;
  		goto error;
  	}

  	if (dev->polling) {
  		rc = -EBUSY;
  		goto error;
  	}

  	rc = dev->ops->start_poll(dev, im_protocols, tm_protocols);

  	if (!rc) {

  		dev->polling = true;

  		dev->rf_mode = NFC_RF_NONE;
  	}

  
  error:
  	device_unlock(&dev->dev);
  	return rc;
  }
  
  /**
   * nfc_stop_poll - stop polling for nfc targets
   *
   * @dev: The nfc device that must stop polling
   */
  int nfc_stop_poll(struct nfc_dev *dev)
  {
  	int rc = 0;

  	pr_debug("dev_name=%s
  ", dev_name(&dev->dev));

  
  	device_lock(&dev->dev);
  
  	if (!device_is_registered(&dev->dev)) {
  		rc = -ENODEV;
  		goto error;
  	}
  
  	if (!dev->polling) {
  		rc = -EINVAL;
  		goto error;
  	}
  
  	dev->ops->stop_poll(dev);
  	dev->polling = false;

  	dev->rf_mode = NFC_RF_NONE;

  
  error:
  	device_unlock(&dev->dev);
  	return rc;
  }

  static struct nfc_target *nfc_find_target(struct nfc_dev *dev, u32 target_idx)
  {
  	int i;

  	for (i = 0; i < dev->n_targets; i++) {

  		if (dev->targets[i].idx == target_idx)
  			return &dev->targets[i];
  	}
  
  	return NULL;
  }

  int nfc_dep_link_up(struct nfc_dev *dev, int target_index, u8 comm_mode)

  {
  	int rc = 0;

  	u8 *gb;
  	size_t gb_len;

  	struct nfc_target *target;

  	pr_debug("dev_name=%s comm %d
  ", dev_name(&dev->dev), comm_mode);

  
  	if (!dev->ops->dep_link_up)
  		return -EOPNOTSUPP;
  
  	device_lock(&dev->dev);
  
  	if (!device_is_registered(&dev->dev)) {
  		rc = -ENODEV;
  		goto error;
  	}
  
  	if (dev->dep_link_up == true) {
  		rc = -EALREADY;
  		goto error;
  	}

  	gb = nfc_llcp_general_bytes(dev, &gb_len);
  	if (gb_len > NFC_MAX_GT_LEN) {
  		rc = -EINVAL;
  		goto error;
  	}

  	target = nfc_find_target(dev, target_index);
  	if (target == NULL) {
  		rc = -ENOTCONN;
  		goto error;
  	}
  
  	rc = dev->ops->dep_link_up(dev, target, comm_mode, gb, gb_len);

  	if (!rc) {

  		dev->active_target = target;

  		dev->rf_mode = NFC_RF_INITIATOR;
  	}

  
  error:
  	device_unlock(&dev->dev);
  	return rc;
  }
  
  int nfc_dep_link_down(struct nfc_dev *dev)
  {
  	int rc = 0;
  
  	pr_debug("dev_name=%s
  ", dev_name(&dev->dev));
  
  	if (!dev->ops->dep_link_down)
  		return -EOPNOTSUPP;
  
  	device_lock(&dev->dev);
  
  	if (!device_is_registered(&dev->dev)) {
  		rc = -ENODEV;
  		goto error;
  	}
  
  	if (dev->dep_link_up == false) {
  		rc = -EALREADY;
  		goto error;
  	}

  	rc = dev->ops->dep_link_down(dev);
  	if (!rc) {
  		dev->dep_link_up = false;

  		dev->active_target = NULL;

  		dev->rf_mode = NFC_RF_NONE;

  		nfc_llcp_mac_is_down(dev);

  		nfc_genl_dep_link_down_event(dev);
  	}
  
  error:
  	device_unlock(&dev->dev);

  	return rc;
  }
  
  int nfc_dep_link_is_up(struct nfc_dev *dev, u32 target_idx,

  		       u8 comm_mode, u8 rf_mode)

  {
  	dev->dep_link_up = true;

  	if (!dev->active_target && rf_mode == NFC_RF_INITIATOR) {

  		struct nfc_target *target;
  
  		target = nfc_find_target(dev, target_idx);
  		if (target == NULL)
  			return -ENOTCONN;
  
  		dev->active_target = target;
  	}
  
  	dev->polling = false;
  	dev->rf_mode = rf_mode;

  	nfc_llcp_mac_is_up(dev, target_idx, comm_mode, rf_mode);

  	return nfc_genl_dep_link_up_event(dev, target_idx, comm_mode, rf_mode);
  }
  EXPORT_SYMBOL(nfc_dep_link_is_up);

  /**
   * nfc_activate_target - prepare the target for data exchange
   *
   * @dev: The nfc device that found the target
   * @target_idx: index of the target that must be activated
   * @protocol: nfc protocol that will be used for data exchange
   */
  int nfc_activate_target(struct nfc_dev *dev, u32 target_idx, u32 protocol)
  {
  	int rc;

  	struct nfc_target *target;

  	pr_debug("dev_name=%s target_idx=%u protocol=%u
  ",
  		 dev_name(&dev->dev), target_idx, protocol);

  
  	device_lock(&dev->dev);
  
  	if (!device_is_registered(&dev->dev)) {
  		rc = -ENODEV;
  		goto error;
  	}

  	if (dev->active_target) {
  		rc = -EBUSY;
  		goto error;
  	}
  
  	target = nfc_find_target(dev, target_idx);
  	if (target == NULL) {
  		rc = -ENOTCONN;
  		goto error;
  	}
  
  	rc = dev->ops->activate_target(dev, target, protocol);

  	if (!rc) {

  		dev->active_target = target;

  		dev->rf_mode = NFC_RF_INITIATOR;

  		if (dev->ops->check_presence && !dev->shutting_down)

  			mod_timer(&dev->check_pres_timer, jiffies +
  				  msecs_to_jiffies(NFC_CHECK_PRES_FREQ_MS));
  	}

  
  error:
  	device_unlock(&dev->dev);
  	return rc;
  }
  
  /**
   * nfc_deactivate_target - deactivate a nfc target
   *
   * @dev: The nfc device that found the target
   * @target_idx: index of the target that must be deactivated
   */

  int nfc_deactivate_target(struct nfc_dev *dev, u32 target_idx, u8 mode)

  {
  	int rc = 0;

  	pr_debug("dev_name=%s target_idx=%u
  ",
  		 dev_name(&dev->dev), target_idx);

  
  	device_lock(&dev->dev);
  
  	if (!device_is_registered(&dev->dev)) {
  		rc = -ENODEV;
  		goto error;
  	}

  	if (dev->active_target == NULL) {
  		rc = -ENOTCONN;
  		goto error;
  	}
  
  	if (dev->active_target->idx != target_idx) {
  		rc = -ENOTCONN;
  		goto error;
  	}

  	if (dev->ops->check_presence)
  		del_timer_sync(&dev->check_pres_timer);

  	dev->ops->deactivate_target(dev, dev->active_target, mode);

  	dev->active_target = NULL;

  
  error:
  	device_unlock(&dev->dev);
  	return rc;
  }
  
  /**
   * nfc_data_exchange - transceive data
   *
   * @dev: The nfc device that found the target
   * @target_idx: index of the target
   * @skb: data to be sent
   * @cb: callback called when the response is received
   * @cb_context: parameter for the callback function
   *
   * The user must wait for the callback before calling this function again.
   */

  int nfc_data_exchange(struct nfc_dev *dev, u32 target_idx, struct sk_buff *skb,
  		      data_exchange_cb_t cb, void *cb_context)

  {
  	int rc;

  	pr_debug("dev_name=%s target_idx=%u skb->len=%u
  ",
  		 dev_name(&dev->dev), target_idx, skb->len);

  
  	device_lock(&dev->dev);
  
  	if (!device_is_registered(&dev->dev)) {
  		rc = -ENODEV;
  		kfree_skb(skb);
  		goto error;
  	}

  	if (dev->rf_mode == NFC_RF_INITIATOR && dev->active_target != NULL) {
  		if (dev->active_target->idx != target_idx) {
  			rc = -EADDRNOTAVAIL;
  			kfree_skb(skb);
  			goto error;
  		}

  		if (dev->ops->check_presence)
  			del_timer_sync(&dev->check_pres_timer);
  
  		rc = dev->ops->im_transceive(dev, dev->active_target, skb, cb,
  					     cb_context);

  		if (!rc && dev->ops->check_presence && !dev->shutting_down)

  			mod_timer(&dev->check_pres_timer, jiffies +
  				  msecs_to_jiffies(NFC_CHECK_PRES_FREQ_MS));
  	} else if (dev->rf_mode == NFC_RF_TARGET && dev->ops->tm_send != NULL) {
  		rc = dev->ops->tm_send(dev, skb);
  	} else {
  		rc = -ENOTCONN;

  		kfree_skb(skb);
  		goto error;
  	}

  error:
  	device_unlock(&dev->dev);
  	return rc;
  }

  struct nfc_se *nfc_find_se(struct nfc_dev *dev, u32 se_idx)

  {

  	struct nfc_se *se;

  	list_for_each_entry(se, &dev->secure_elements, list)

  		if (se->idx == se_idx)
  			return se;
  
  	return NULL;
  }

  EXPORT_SYMBOL(nfc_find_se);

  
  int nfc_enable_se(struct nfc_dev *dev, u32 se_idx)
  {

  	struct nfc_se *se;
  	int rc;
  
  	pr_debug("%s se index %d
  ", dev_name(&dev->dev), se_idx);
  
  	device_lock(&dev->dev);
  
  	if (!device_is_registered(&dev->dev)) {
  		rc = -ENODEV;
  		goto error;
  	}
  
  	if (!dev->dev_up) {
  		rc = -ENODEV;
  		goto error;
  	}
  
  	if (dev->polling) {
  		rc = -EBUSY;
  		goto error;
  	}
  
  	if (!dev->ops->enable_se || !dev->ops->disable_se) {
  		rc = -EOPNOTSUPP;
  		goto error;
  	}

  	se = nfc_find_se(dev, se_idx);

  	if (!se) {
  		rc = -EINVAL;
  		goto error;
  	}

  	if (se->state == NFC_SE_ENABLED) {

  		rc = -EALREADY;
  		goto error;
  	}
  
  	rc = dev->ops->enable_se(dev, se_idx);

  	if (rc >= 0)
  		se->state = NFC_SE_ENABLED;

  
  error:
  	device_unlock(&dev->dev);
  	return rc;
  }
  
  int nfc_disable_se(struct nfc_dev *dev, u32 se_idx)
  {

  	struct nfc_se *se;
  	int rc;
  
  	pr_debug("%s se index %d
  ", dev_name(&dev->dev), se_idx);
  
  	device_lock(&dev->dev);
  
  	if (!device_is_registered(&dev->dev)) {
  		rc = -ENODEV;
  		goto error;
  	}
  
  	if (!dev->dev_up) {
  		rc = -ENODEV;
  		goto error;
  	}
  
  	if (!dev->ops->enable_se || !dev->ops->disable_se) {
  		rc = -EOPNOTSUPP;
  		goto error;
  	}

  	se = nfc_find_se(dev, se_idx);

  	if (!se) {
  		rc = -EINVAL;
  		goto error;
  	}

  	if (se->state == NFC_SE_DISABLED) {

  		rc = -EALREADY;
  		goto error;
  	}
  
  	rc = dev->ops->disable_se(dev, se_idx);

  	if (rc >= 0)
  		se->state = NFC_SE_DISABLED;

  
  error:
  	device_unlock(&dev->dev);
  	return rc;
  }

  int nfc_set_remote_general_bytes(struct nfc_dev *dev, u8 *gb, u8 gb_len)
  {

  	pr_debug("dev_name=%s gb_len=%d
  ", dev_name(&dev->dev), gb_len);

  	return nfc_llcp_set_remote_gb(dev, gb, gb_len);

  }
  EXPORT_SYMBOL(nfc_set_remote_general_bytes);

  u8 *nfc_get_local_general_bytes(struct nfc_dev *dev, size_t *gb_len)
  {
  	pr_debug("dev_name=%s
  ", dev_name(&dev->dev));
  
  	return nfc_llcp_general_bytes(dev, gb_len);
  }
  EXPORT_SYMBOL(nfc_get_local_general_bytes);

  int nfc_tm_data_received(struct nfc_dev *dev, struct sk_buff *skb)
  {
  	/* Only LLCP target mode for now */
  	if (dev->dep_link_up == false) {
  		kfree_skb(skb);
  		return -ENOLINK;
  	}
  
  	return nfc_llcp_data_received(dev, skb);
  }
  EXPORT_SYMBOL(nfc_tm_data_received);

  int nfc_tm_activated(struct nfc_dev *dev, u32 protocol, u8 comm_mode,
  		     u8 *gb, size_t gb_len)
  {
  	int rc;
  
  	device_lock(&dev->dev);
  
  	dev->polling = false;
  
  	if (gb != NULL) {
  		rc = nfc_set_remote_general_bytes(dev, gb, gb_len);
  		if (rc < 0)
  			goto out;
  	}

  	dev->rf_mode = NFC_RF_TARGET;

  	if (protocol == NFC_PROTO_NFC_DEP_MASK)
  		nfc_dep_link_is_up(dev, 0, comm_mode, NFC_RF_TARGET);
  
  	rc = nfc_genl_tm_activated(dev, protocol);
  
  out:
  	device_unlock(&dev->dev);
  
  	return rc;
  }
  EXPORT_SYMBOL(nfc_tm_activated);
  
  int nfc_tm_deactivated(struct nfc_dev *dev)
  {
  	dev->dep_link_up = false;

  	dev->rf_mode = NFC_RF_NONE;

  
  	return nfc_genl_tm_deactivated(dev);
  }
  EXPORT_SYMBOL(nfc_tm_deactivated);

  /**

   * nfc_alloc_send_skb - allocate a skb for data exchange responses

   *
   * @size: size to allocate
   * @gfp: gfp flags
   */

  struct sk_buff *nfc_alloc_send_skb(struct nfc_dev *dev, struct sock *sk,

  				   unsigned int flags, unsigned int size,
  				   unsigned int *err)

  {
  	struct sk_buff *skb;
  	unsigned int total_size;
  
  	total_size = size +
  		dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
  
  	skb = sock_alloc_send_skb(sk, total_size, flags & MSG_DONTWAIT, err);
  	if (skb)
  		skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
  
  	return skb;
  }
  
  /**
   * nfc_alloc_recv_skb - allocate a skb for data exchange responses
   *
   * @size: size to allocate
   * @gfp: gfp flags
   */
  struct sk_buff *nfc_alloc_recv_skb(unsigned int size, gfp_t gfp)

  {
  	struct sk_buff *skb;
  	unsigned int total_size;
  
  	total_size = size + 1;
  	skb = alloc_skb(total_size, gfp);
  
  	if (skb)
  		skb_reserve(skb, 1);
  
  	return skb;
  }

  EXPORT_SYMBOL(nfc_alloc_recv_skb);

  /**
   * nfc_targets_found - inform that targets were found
   *
   * @dev: The nfc device that found the targets
   * @targets: array of nfc targets found
   * @ntargets: targets array size
   *
   * The device driver must call this function when one or many nfc targets
   * are found. After calling this function, the device driver must stop
   * polling for targets.

   * NOTE: This function can be called with targets=NULL and n_targets=0 to
   * notify a driver error, meaning that the polling operation cannot complete.

   * IMPORTANT: this function must not be called from an atomic context.
   * In addition, it must also not be called from a context that would prevent
   * the NFC Core to call other nfc ops entry point concurrently.

   */

  int nfc_targets_found(struct nfc_dev *dev,
  		      struct nfc_target *targets, int n_targets)

  {

  	int i;

  	pr_debug("dev_name=%s n_targets=%d
  ", dev_name(&dev->dev), n_targets);

  	for (i = 0; i < n_targets; i++)

  		targets[i].idx = dev->target_next_idx++;

  	device_lock(&dev->dev);

  	if (dev->polling == false) {
  		device_unlock(&dev->dev);
  		return 0;
  	}
  
  	dev->polling = false;

  	dev->targets_generation++;
  
  	kfree(dev->targets);

  	dev->targets = NULL;

  	if (targets) {
  		dev->targets = kmemdup(targets,
  				       n_targets * sizeof(struct nfc_target),
  				       GFP_ATOMIC);
  
  		if (!dev->targets) {
  			dev->n_targets = 0;
  			device_unlock(&dev->dev);
  			return -ENOMEM;
  		}

  	}
  
  	dev->n_targets = n_targets;

  	device_unlock(&dev->dev);

  
  	nfc_genl_targets_found(dev);
  
  	return 0;
  }
  EXPORT_SYMBOL(nfc_targets_found);

  /**
   * nfc_target_lost - inform that an activated target went out of field
   *
   * @dev: The nfc device that had the activated target in field
   * @target_idx: the nfc index of the target
   *
   * The device driver must call this function when the activated target
   * goes out of the field.
   * IMPORTANT: this function must not be called from an atomic context.
   * In addition, it must also not be called from a context that would prevent
   * the NFC Core to call other nfc ops entry point concurrently.
   */

  int nfc_target_lost(struct nfc_dev *dev, u32 target_idx)
  {
  	struct nfc_target *tg;
  	int i;
  
  	pr_debug("dev_name %s n_target %d
  ", dev_name(&dev->dev), target_idx);

  	device_lock(&dev->dev);

  
  	for (i = 0; i < dev->n_targets; i++) {
  		tg = &dev->targets[i];
  		if (tg->idx == target_idx)
  			break;
  	}
  
  	if (i == dev->n_targets) {

  		device_unlock(&dev->dev);

  		return -EINVAL;
  	}
  
  	dev->targets_generation++;
  	dev->n_targets--;

  	dev->active_target = NULL;

  
  	if (dev->n_targets) {
  		memcpy(&dev->targets[i], &dev->targets[i + 1],
  		       (dev->n_targets - i) * sizeof(struct nfc_target));
  	} else {
  		kfree(dev->targets);
  		dev->targets = NULL;
  	}

  	device_unlock(&dev->dev);

  
  	nfc_genl_target_lost(dev, target_idx);
  
  	return 0;
  }
  EXPORT_SYMBOL(nfc_target_lost);

  inline void nfc_driver_failure(struct nfc_dev *dev, int err)

  {

  	nfc_targets_found(dev, NULL, 0);

  }
  EXPORT_SYMBOL(nfc_driver_failure);

  int nfc_add_se(struct nfc_dev *dev, u32 se_idx, u16 type)
  {

  	struct nfc_se *se;

  	int rc;

  
  	pr_debug("%s se index %d
  ", dev_name(&dev->dev), se_idx);

  	se = nfc_find_se(dev, se_idx);

  	if (se)
  		return -EALREADY;

  
  	se = kzalloc(sizeof(struct nfc_se), GFP_KERNEL);
  	if (!se)
  		return -ENOMEM;
  
  	se->idx = se_idx;
  	se->type = type;
  	se->state = NFC_SE_DISABLED;
  	INIT_LIST_HEAD(&se->list);
  
  	list_add(&se->list, &dev->secure_elements);

  	rc = nfc_genl_se_added(dev, se_idx, type);
  	if (rc < 0) {
  		list_del(&se->list);
  		kfree(se);
  
  		return rc;
  	}

  	return 0;
  }
  EXPORT_SYMBOL(nfc_add_se);
  
  int nfc_remove_se(struct nfc_dev *dev, u32 se_idx)
  {
  	struct nfc_se *se, *n;

  	int rc;

  
  	pr_debug("%s se index %d
  ", dev_name(&dev->dev), se_idx);
  
  	list_for_each_entry_safe(se, n, &dev->secure_elements, list)
  		if (se->idx == se_idx) {

  			rc = nfc_genl_se_removed(dev, se_idx);
  			if (rc < 0)
  				return rc;

  			list_del(&se->list);
  			kfree(se);
  
  			return 0;
  		}
  
  	return -EINVAL;
  }
  EXPORT_SYMBOL(nfc_remove_se);

  int nfc_se_transaction(struct nfc_dev *dev, u8 se_idx,
  		       struct nfc_evt_transaction *evt_transaction)
  {
  	int rc;
  
  	pr_debug("transaction: %x
  ", se_idx);
  
  	device_lock(&dev->dev);
  
  	if (!evt_transaction) {
  		rc = -EPROTO;
  		goto out;
  	}
  
  	rc = nfc_genl_se_transaction(dev, se_idx, evt_transaction);
  out:
  	device_unlock(&dev->dev);
  	return rc;
  }
  EXPORT_SYMBOL(nfc_se_transaction);

  int nfc_se_connectivity(struct nfc_dev *dev, u8 se_idx)
  {
  	int rc;
  
  	pr_debug("connectivity: %x
  ", se_idx);
  
  	device_lock(&dev->dev);
  	rc = nfc_genl_se_connectivity(dev, se_idx);
  	device_unlock(&dev->dev);
  	return rc;
  }
  EXPORT_SYMBOL(nfc_se_connectivity);

  static void nfc_release(struct device *d)
  {
  	struct nfc_dev *dev = to_nfc_dev(d);

  	struct nfc_se *se, *n;

  	pr_debug("dev_name=%s
  ", dev_name(&dev->dev));

  	nfc_genl_data_exit(&dev->genl_data);
  	kfree(dev->targets);

  
  	list_for_each_entry_safe(se, n, &dev->secure_elements, list) {
  			nfc_genl_se_removed(dev, se->idx);
  			list_del(&se->list);
  			kfree(se);
  	}

  	ida_simple_remove(&nfc_index_ida, dev->idx);

  	kfree(dev);
  }

  static void nfc_check_pres_work(struct work_struct *work)
  {
  	struct nfc_dev *dev = container_of(work, struct nfc_dev,
  					   check_pres_work);
  	int rc;
  
  	device_lock(&dev->dev);

  	if (dev->active_target && timer_pending(&dev->check_pres_timer) == 0) {
  		rc = dev->ops->check_presence(dev, dev->active_target);

  		if (rc == -EOPNOTSUPP)
  			goto exit;

  		if (rc) {

  			u32 active_target_idx = dev->active_target->idx;
  			device_unlock(&dev->dev);
  			nfc_target_lost(dev, active_target_idx);
  			return;

  		}

  
  		if (!dev->shutting_down)
  			mod_timer(&dev->check_pres_timer, jiffies +
  				  msecs_to_jiffies(NFC_CHECK_PRES_FREQ_MS));

  	}

  exit:

  	device_unlock(&dev->dev);
  }
  
  static void nfc_check_pres_timeout(unsigned long data)
  {
  	struct nfc_dev *dev = (struct nfc_dev *)data;

  	schedule_work(&dev->check_pres_work);

  }

  struct class nfc_class = {
  	.name = "nfc",
  	.dev_release = nfc_release,
  };
  EXPORT_SYMBOL(nfc_class);

  static int match_idx(struct device *d, const void *data)

  {
  	struct nfc_dev *dev = to_nfc_dev(d);

  	const unsigned int *idx = data;

  
  	return dev->idx == *idx;
  }

  struct nfc_dev *nfc_get_device(unsigned int idx)

  {
  	struct device *d;
  
  	d = class_find_device(&nfc_class, NULL, &idx, match_idx);
  	if (!d)
  		return NULL;
  
  	return to_nfc_dev(d);
  }
  
  /**
   * nfc_allocate_device - allocate a new nfc device
   *
   * @ops: device operations
   * @supported_protocols: NFC protocols supported by the device
   */
  struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,

  				    u32 supported_protocols,
  				    int tx_headroom, int tx_tailroom)

  {

  	struct nfc_dev *dev;

  	int rc;

  
  	if (!ops->start_poll || !ops->stop_poll || !ops->activate_target ||

  	    !ops->deactivate_target || !ops->im_transceive)

  		return NULL;
  
  	if (!supported_protocols)
  		return NULL;
  
  	dev = kzalloc(sizeof(struct nfc_dev), GFP_KERNEL);
  	if (!dev)
  		return NULL;

  	rc = ida_simple_get(&nfc_index_ida, 0, 0, GFP_KERNEL);
  	if (rc < 0)
  		goto err_free_dev;
  	dev->idx = rc;
  
  	dev->dev.class = &nfc_class;
  	dev_set_name(&dev->dev, "nfc%d", dev->idx);
  	device_initialize(&dev->dev);

  	dev->ops = ops;
  	dev->supported_protocols = supported_protocols;

  	dev->tx_headroom = tx_headroom;
  	dev->tx_tailroom = tx_tailroom;

  	INIT_LIST_HEAD(&dev->secure_elements);

  	nfc_genl_data_init(&dev->genl_data);

  	dev->rf_mode = NFC_RF_NONE;

  	/* first generation must not be 0 */
  	dev->targets_generation = 1;

  	if (ops->check_presence) {

  		init_timer(&dev->check_pres_timer);
  		dev->check_pres_timer.data = (unsigned long)dev;
  		dev->check_pres_timer.function = nfc_check_pres_timeout;
  
  		INIT_WORK(&dev->check_pres_work, nfc_check_pres_work);

  	}

  	return dev;

  
  err_free_dev:
  	kfree(dev);

  	return NULL;

  }
  EXPORT_SYMBOL(nfc_allocate_device);
  
  /**
   * nfc_register_device - register a nfc device in the nfc subsystem
   *
   * @dev: The nfc device to register
   */
  int nfc_register_device(struct nfc_dev *dev)
  {
  	int rc;

  	pr_debug("dev_name=%s
  ", dev_name(&dev->dev));

  
  	mutex_lock(&nfc_devlist_mutex);
  	nfc_devlist_generation++;
  	rc = device_add(&dev->dev);
  	mutex_unlock(&nfc_devlist_mutex);

  	if (rc < 0)
  		return rc;

  	rc = nfc_llcp_register_device(dev);
  	if (rc)
  		pr_err("Could not register llcp device
  ");

  	rc = nfc_genl_device_added(dev);
  	if (rc)

  		pr_debug("The userspace won't be notified that the device %s was added
  ",
  			 dev_name(&dev->dev));

  	dev->rfkill = rfkill_alloc(dev_name(&dev->dev), &dev->dev,
  				   RFKILL_TYPE_NFC, &nfc_rfkill_ops, dev);
  	if (dev->rfkill) {
  		if (rfkill_register(dev->rfkill) < 0) {
  			rfkill_destroy(dev->rfkill);
  			dev->rfkill = NULL;
  		}
  	}

  	return 0;

  }
  EXPORT_SYMBOL(nfc_register_device);
  
  /**
   * nfc_unregister_device - unregister a nfc device in the nfc subsystem
   *
   * @dev: The nfc device to unregister
   */
  void nfc_unregister_device(struct nfc_dev *dev)
  {

  	int rc;

  	pr_debug("dev_name=%s
  ", dev_name(&dev->dev));

  	if (dev->rfkill) {
  		rfkill_unregister(dev->rfkill);
  		rfkill_destroy(dev->rfkill);
  	}

  	if (dev->ops->check_presence) {
  		device_lock(&dev->dev);
  		dev->shutting_down = true;
  		device_unlock(&dev->dev);
  		del_timer_sync(&dev->check_pres_timer);
  		cancel_work_sync(&dev->check_pres_work);
  	}

  	rc = nfc_genl_device_removed(dev);
  	if (rc)
  		pr_debug("The userspace won't be notified that the device %s "
  			 "was removed
  ", dev_name(&dev->dev));

  	nfc_llcp_unregister_device(dev);

  	mutex_lock(&nfc_devlist_mutex);
  	nfc_devlist_generation++;
  	device_del(&dev->dev);
  	mutex_unlock(&nfc_devlist_mutex);

  }
  EXPORT_SYMBOL(nfc_unregister_device);
  
  static int __init nfc_init(void)
  {

  	int rc;

  	pr_info("NFC Core ver %s
  ", VERSION);

  	rc = class_register(&nfc_class);
  	if (rc)
  		return rc;
  
  	rc = nfc_genl_init();
  	if (rc)
  		goto err_genl;
  
  	/* the first generation must not be 0 */
  	nfc_devlist_generation = 1;

  	rc = rawsock_init();
  	if (rc)
  		goto err_rawsock;

  	rc = nfc_llcp_init();
  	if (rc)
  		goto err_llcp_sock;

  	rc = af_nfc_init();
  	if (rc)
  		goto err_af_nfc;

  	return 0;

  err_af_nfc:

  	nfc_llcp_exit();
  err_llcp_sock:

  	rawsock_exit();
  err_rawsock:

  	nfc_genl_exit();

  err_genl:
  	class_unregister(&nfc_class);
  	return rc;

  }
  
  static void __exit nfc_exit(void)
  {

  	af_nfc_exit();

  	nfc_llcp_exit();

  	rawsock_exit();

  	nfc_genl_exit();

  	class_unregister(&nfc_class);
  }
  
  subsys_initcall(nfc_init);
  module_exit(nfc_exit);
  
  MODULE_AUTHOR("Lauro Ramos Venancio <lauro.venancio@openbossa.org>");
  MODULE_DESCRIPTION("NFC Core ver " VERSION);
  MODULE_VERSION(VERSION);
  MODULE_LICENSE("GPL");

  MODULE_ALIAS_NETPROTO(PF_NFC);

  MODULE_ALIAS_GENL_FAMILY(NFC_GENL_NAME);