/*
   * NFC Digital Protocol stack
   * Copyright (c) 2013, Intel Corporation.
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms and conditions of the GNU General Public License,
   * version 2, as published by the Free Software Foundation.
   *
   * This program is distributed in the hope 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.
   *
   */

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

  #include "digital.h"

  #define DIGITAL_NFC_DEP_N_RETRY_NACK	2

  #define DIGITAL_NFC_DEP_N_RETRY_ATN	2

  #define DIGITAL_NFC_DEP_FRAME_DIR_OUT 0xD4
  #define DIGITAL_NFC_DEP_FRAME_DIR_IN  0xD5
  
  #define DIGITAL_NFC_DEP_NFCA_SOD_SB   0xF0
  
  #define DIGITAL_CMD_ATR_REQ 0x00
  #define DIGITAL_CMD_ATR_RES 0x01
  #define DIGITAL_CMD_PSL_REQ 0x04
  #define DIGITAL_CMD_PSL_RES 0x05
  #define DIGITAL_CMD_DEP_REQ 0x06
  #define DIGITAL_CMD_DEP_RES 0x07
  
  #define DIGITAL_ATR_REQ_MIN_SIZE 16
  #define DIGITAL_ATR_REQ_MAX_SIZE 64

  #define DIGITAL_ATR_RES_TO_WT(s)	((s) & 0xF)

  #define DIGITAL_DID_MAX	14

  #define DIGITAL_PAYLOAD_SIZE_MAX	254
  #define DIGITAL_PAYLOAD_BITS_TO_PP(s)	(((s) & 0x3) << 4)
  #define DIGITAL_PAYLOAD_PP_TO_BITS(s)	(((s) >> 4) & 0x3)
  #define DIGITAL_PAYLOAD_BITS_TO_FSL(s)	((s) & 0x3)
  #define DIGITAL_PAYLOAD_FSL_TO_BITS(s)	((s) & 0x3)

  #define DIGITAL_GB_BIT	0x02

  #define DIGITAL_NFC_DEP_REQ_RES_HEADROOM	2 /* SoD: [SB (NFC-A)] + LEN */
  #define DIGITAL_NFC_DEP_REQ_RES_TAILROOM	2 /* EoD: 2-byte CRC */

  #define DIGITAL_NFC_DEP_PFB_TYPE(pfb) ((pfb) & 0xE0)
  
  #define DIGITAL_NFC_DEP_PFB_TIMEOUT_BIT 0x10

  #define DIGITAL_NFC_DEP_PFB_MI_BIT	0x10
  #define DIGITAL_NFC_DEP_PFB_NACK_BIT	0x10

  #define DIGITAL_NFC_DEP_PFB_DID_BIT	0x04

  
  #define DIGITAL_NFC_DEP_PFB_IS_TIMEOUT(pfb) \
  				((pfb) & DIGITAL_NFC_DEP_PFB_TIMEOUT_BIT)

  #define DIGITAL_NFC_DEP_MI_BIT_SET(pfb)  ((pfb) & DIGITAL_NFC_DEP_PFB_MI_BIT)
  #define DIGITAL_NFC_DEP_NACK_BIT_SET(pfb) ((pfb) & DIGITAL_NFC_DEP_PFB_NACK_BIT)

  #define DIGITAL_NFC_DEP_NAD_BIT_SET(pfb) ((pfb) & 0x08)

  #define DIGITAL_NFC_DEP_DID_BIT_SET(pfb) ((pfb) & DIGITAL_NFC_DEP_PFB_DID_BIT)

  #define DIGITAL_NFC_DEP_PFB_PNI(pfb)     ((pfb) & 0x03)

  #define DIGITAL_NFC_DEP_RTOX_VALUE(data) ((data) & 0x3F)
  #define DIGITAL_NFC_DEP_RTOX_MAX	 59

  #define DIGITAL_NFC_DEP_PFB_I_PDU          0x00
  #define DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU   0x40
  #define DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU 0x80
  
  struct digital_atr_req {
  	u8 dir;
  	u8 cmd;
  	u8 nfcid3[10];
  	u8 did;
  	u8 bs;
  	u8 br;
  	u8 pp;
  	u8 gb[0];
  } __packed;
  
  struct digital_atr_res {
  	u8 dir;
  	u8 cmd;
  	u8 nfcid3[10];
  	u8 did;
  	u8 bs;
  	u8 br;
  	u8 to;
  	u8 pp;
  	u8 gb[0];
  } __packed;
  
  struct digital_psl_req {
  	u8 dir;
  	u8 cmd;
  	u8 did;
  	u8 brs;
  	u8 fsl;
  } __packed;
  
  struct digital_psl_res {
  	u8 dir;
  	u8 cmd;
  	u8 did;
  } __packed;
  
  struct digital_dep_req_res {
  	u8 dir;
  	u8 cmd;
  	u8 pfb;
  } __packed;
  
  static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,
  				    struct sk_buff *resp);

  static void digital_tg_recv_dep_req(struct nfc_digital_dev *ddev, void *arg,
  				    struct sk_buff *resp);

  static const u8 digital_payload_bits_map[4] = {
  	[0] = 64,
  	[1] = 128,
  	[2] = 192,
  	[3] = 254
  };

  /* Response Waiting Time for ATR_RES PDU in ms
   *
   * RWT(ATR_RES) = RWT(nfcdep,activation) + dRWT(nfcdep) + dT(nfcdep,initiator)
   *
   * with:
   *  RWT(nfcdep,activation) = 4096 * 2^12 / f(c) s
   *  dRWT(nfcdep) = 16 / f(c) s
   *  dT(nfcdep,initiator) = 100 ms
   *  f(c) = 13560000 Hz
   */
  #define DIGITAL_ATR_RES_RWT 1337
  
  /* Response Waiting Time for other DEP PDUs in ms
   *
   * max_rwt = rwt + dRWT(nfcdep) + dT(nfcdep,initiator)
   *
   * with:
   *  rwt = (256 * 16 / f(c)) * 2^wt s
   *  dRWT(nfcdep) = 16 / f(c) s
   *  dT(nfcdep,initiator) = 100 ms
   *  f(c) = 13560000 Hz
   *  0 <= wt <= 14 (given by the target by the TO field of ATR_RES response)
   */
  #define DIGITAL_NFC_DEP_IN_MAX_WT 14

  #define DIGITAL_NFC_DEP_TG_MAX_WT 14

  static const u16 digital_rwt_map[DIGITAL_NFC_DEP_IN_MAX_WT + 1] = {
  	100,  101,  101,  102,  105,
  	110,  119,  139,  177,  255,
  	409,  719, 1337, 2575, 5049,
  };

  static u8 digital_payload_bits_to_size(u8 payload_bits)
  {
  	if (payload_bits >= ARRAY_SIZE(digital_payload_bits_map))
  		return 0;
  
  	return digital_payload_bits_map[payload_bits];
  }
  
  static u8 digital_payload_size_to_bits(u8 payload_size)
  {
  	int i;
  
  	for (i = 0; i < ARRAY_SIZE(digital_payload_bits_map); i++)
  		if (digital_payload_bits_map[i] == payload_size)
  			return i;
  
  	return 0xff;
  }

  static void digital_skb_push_dep_sod(struct nfc_digital_dev *ddev,
  				     struct sk_buff *skb)
  {
  	skb_push(skb, sizeof(u8));
  
  	skb->data[0] = skb->len;
  
  	if (ddev->curr_rf_tech == NFC_DIGITAL_RF_TECH_106A)

  		*(u8 *)skb_push(skb, sizeof(u8)) = DIGITAL_NFC_DEP_NFCA_SOD_SB;

  }
  
  static int digital_skb_pull_dep_sod(struct nfc_digital_dev *ddev,
  				    struct sk_buff *skb)
  {
  	u8 size;
  
  	if (skb->len < 2)
  		return -EIO;
  
  	if (ddev->curr_rf_tech == NFC_DIGITAL_RF_TECH_106A)
  		skb_pull(skb, sizeof(u8));
  
  	size = skb->data[0];
  	if (size != skb->len)
  		return -EIO;
  
  	skb_pull(skb, sizeof(u8));
  
  	return 0;
  }

  static struct sk_buff *
  digital_send_dep_data_prep(struct nfc_digital_dev *ddev, struct sk_buff *skb,
  			   struct digital_dep_req_res *dep_req_res,
  			   struct digital_data_exch *data_exch)
  {
  	struct sk_buff *new_skb;
  
  	if (skb->len > ddev->remote_payload_max) {
  		dep_req_res->pfb |= DIGITAL_NFC_DEP_PFB_MI_BIT;
  
  		new_skb = digital_skb_alloc(ddev, ddev->remote_payload_max);
  		if (!new_skb) {
  			kfree_skb(ddev->chaining_skb);
  			ddev->chaining_skb = NULL;
  
  			return ERR_PTR(-ENOMEM);
  		}

  		skb_put_data(new_skb, skb->data, ddev->remote_payload_max);

  		skb_pull(skb, ddev->remote_payload_max);
  
  		ddev->chaining_skb = skb;
  		ddev->data_exch = data_exch;
  	} else {
  		ddev->chaining_skb = NULL;
  		new_skb = skb;
  	}
  
  	return new_skb;
  }

  static struct sk_buff *
  digital_recv_dep_data_gather(struct nfc_digital_dev *ddev, u8 pfb,
  			     struct sk_buff *resp,
  			     int (*send_ack)(struct nfc_digital_dev *ddev,
  					     struct digital_data_exch
  							     *data_exch),
  			     struct digital_data_exch *data_exch)
  {
  	struct sk_buff *new_skb;
  	int rc;
  
  	if (DIGITAL_NFC_DEP_MI_BIT_SET(pfb) && (!ddev->chaining_skb)) {
  		ddev->chaining_skb =
  			nfc_alloc_recv_skb(8 * ddev->local_payload_max,
  					   GFP_KERNEL);
  		if (!ddev->chaining_skb) {
  			rc = -ENOMEM;
  			goto error;
  		}
  	}
  
  	if (ddev->chaining_skb) {
  		if (resp->len > skb_tailroom(ddev->chaining_skb)) {
  			new_skb = skb_copy_expand(ddev->chaining_skb,
  						  skb_headroom(
  							  ddev->chaining_skb),
  						  8 * ddev->local_payload_max,
  						  GFP_KERNEL);
  			if (!new_skb) {
  				rc = -ENOMEM;
  				goto error;
  			}
  
  			kfree_skb(ddev->chaining_skb);
  			ddev->chaining_skb = new_skb;
  		}

  		skb_put_data(ddev->chaining_skb, resp->data, resp->len);

  
  		kfree_skb(resp);
  		resp = NULL;
  
  		if (DIGITAL_NFC_DEP_MI_BIT_SET(pfb)) {
  			rc = send_ack(ddev, data_exch);
  			if (rc)
  				goto error;
  
  			return NULL;
  		}
  
  		resp = ddev->chaining_skb;
  		ddev->chaining_skb = NULL;
  	}
  
  	return resp;
  
  error:
  	kfree_skb(resp);
  
  	kfree_skb(ddev->chaining_skb);
  	ddev->chaining_skb = NULL;
  
  	return ERR_PTR(rc);
  }

  static void digital_in_recv_psl_res(struct nfc_digital_dev *ddev, void *arg,
  				    struct sk_buff *resp)
  {
  	struct nfc_target *target = arg;
  	struct digital_psl_res *psl_res;
  	int rc;
  
  	if (IS_ERR(resp)) {
  		rc = PTR_ERR(resp);
  		resp = NULL;
  		goto exit;
  	}
  
  	rc = ddev->skb_check_crc(resp);
  	if (rc) {
  		PROTOCOL_ERR("14.4.1.6");
  		goto exit;
  	}
  
  	rc = digital_skb_pull_dep_sod(ddev, resp);
  	if (rc) {
  		PROTOCOL_ERR("14.4.1.2");
  		goto exit;
  	}
  
  	psl_res = (struct digital_psl_res *)resp->data;
  
  	if ((resp->len != sizeof(*psl_res)) ||
  	    (psl_res->dir != DIGITAL_NFC_DEP_FRAME_DIR_IN) ||
  	    (psl_res->cmd != DIGITAL_CMD_PSL_RES)) {
  		rc = -EIO;
  		goto exit;
  	}
  
  	rc = digital_in_configure_hw(ddev, NFC_DIGITAL_CONFIG_RF_TECH,
  				     NFC_DIGITAL_RF_TECH_424F);
  	if (rc)
  		goto exit;
  
  	rc = digital_in_configure_hw(ddev, NFC_DIGITAL_CONFIG_FRAMING,
  				     NFC_DIGITAL_FRAMING_NFCF_NFC_DEP);
  	if (rc)
  		goto exit;
  
  	if (!DIGITAL_DRV_CAPS_IN_CRC(ddev) &&
  	    (ddev->curr_rf_tech == NFC_DIGITAL_RF_TECH_106A)) {
  		ddev->skb_add_crc = digital_skb_add_crc_f;
  		ddev->skb_check_crc = digital_skb_check_crc_f;
  	}
  
  	ddev->curr_rf_tech = NFC_DIGITAL_RF_TECH_424F;
  
  	nfc_dep_link_is_up(ddev->nfc_dev, target->idx, NFC_COMM_ACTIVE,
  			   NFC_RF_INITIATOR);
  
  	ddev->curr_nfc_dep_pni = 0;
  
  exit:
  	dev_kfree_skb(resp);
  
  	if (rc)
  		ddev->curr_protocol = 0;
  }
  
  static int digital_in_send_psl_req(struct nfc_digital_dev *ddev,
  				   struct nfc_target *target)
  {
  	struct sk_buff *skb;
  	struct digital_psl_req *psl_req;

  	int rc;

  	u8 payload_size, payload_bits;

  
  	skb = digital_skb_alloc(ddev, sizeof(*psl_req));
  	if (!skb)
  		return -ENOMEM;
  
  	skb_put(skb, sizeof(*psl_req));
  
  	psl_req = (struct digital_psl_req *)skb->data;
  
  	psl_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;
  	psl_req->cmd = DIGITAL_CMD_PSL_REQ;
  	psl_req->did = 0;
  	psl_req->brs = (0x2 << 3) | 0x2; /* 424F both directions */

  
  	payload_size = min(ddev->local_payload_max, ddev->remote_payload_max);
  	payload_bits = digital_payload_size_to_bits(payload_size);
  	psl_req->fsl = DIGITAL_PAYLOAD_BITS_TO_FSL(payload_bits);
  
  	ddev->local_payload_max = payload_size;
  	ddev->remote_payload_max = payload_size;

  
  	digital_skb_push_dep_sod(ddev, skb);
  
  	ddev->skb_add_crc(skb);

  	rc = digital_in_send_cmd(ddev, skb, ddev->dep_rwt,
  				 digital_in_recv_psl_res, target);

  	if (rc)
  		kfree_skb(skb);
  
  	return rc;

  }

  static void digital_in_recv_atr_res(struct nfc_digital_dev *ddev, void *arg,
  				 struct sk_buff *resp)
  {
  	struct nfc_target *target = arg;
  	struct digital_atr_res *atr_res;

  	u8 gb_len, payload_bits;

  	u8 wt;

  	int rc;
  
  	if (IS_ERR(resp)) {
  		rc = PTR_ERR(resp);
  		resp = NULL;
  		goto exit;
  	}
  
  	rc = ddev->skb_check_crc(resp);
  	if (rc) {
  		PROTOCOL_ERR("14.4.1.6");
  		goto exit;
  	}
  
  	rc = digital_skb_pull_dep_sod(ddev, resp);
  	if (rc) {
  		PROTOCOL_ERR("14.4.1.2");
  		goto exit;
  	}
  
  	if (resp->len < sizeof(struct digital_atr_res)) {
  		rc = -EIO;
  		goto exit;
  	}
  
  	gb_len = resp->len - sizeof(struct digital_atr_res);
  
  	atr_res = (struct digital_atr_res *)resp->data;

  	wt = DIGITAL_ATR_RES_TO_WT(atr_res->to);
  	if (wt > DIGITAL_NFC_DEP_IN_MAX_WT)
  		wt = DIGITAL_NFC_DEP_IN_MAX_WT;
  	ddev->dep_rwt = digital_rwt_map[wt];

  	payload_bits = DIGITAL_PAYLOAD_PP_TO_BITS(atr_res->pp);
  	ddev->remote_payload_max = digital_payload_bits_to_size(payload_bits);
  
  	if (!ddev->remote_payload_max) {
  		rc = -EINVAL;
  		goto exit;
  	}

  	rc = nfc_set_remote_general_bytes(ddev->nfc_dev, atr_res->gb, gb_len);
  	if (rc)
  		goto exit;

  	if ((ddev->protocols & NFC_PROTO_FELICA_MASK) &&
  	    (ddev->curr_rf_tech != NFC_DIGITAL_RF_TECH_424F)) {
  		rc = digital_in_send_psl_req(ddev, target);
  		if (!rc)
  			goto exit;
  	}

  	rc = nfc_dep_link_is_up(ddev->nfc_dev, target->idx, NFC_COMM_ACTIVE,
  				NFC_RF_INITIATOR);
  
  	ddev->curr_nfc_dep_pni = 0;
  
  exit:
  	dev_kfree_skb(resp);
  
  	if (rc)
  		ddev->curr_protocol = 0;
  }
  
  int digital_in_send_atr_req(struct nfc_digital_dev *ddev,
  			    struct nfc_target *target, __u8 comm_mode, __u8 *gb,
  			    size_t gb_len)
  {
  	struct sk_buff *skb;
  	struct digital_atr_req *atr_req;
  	uint size;

  	int rc;

  	u8 payload_bits;

  
  	size = DIGITAL_ATR_REQ_MIN_SIZE + gb_len;
  
  	if (size > DIGITAL_ATR_REQ_MAX_SIZE) {
  		PROTOCOL_ERR("14.6.1.1");
  		return -EINVAL;
  	}
  
  	skb = digital_skb_alloc(ddev, size);
  	if (!skb)
  		return -ENOMEM;
  
  	skb_put(skb, sizeof(struct digital_atr_req));
  
  	atr_req = (struct digital_atr_req *)skb->data;
  	memset(atr_req, 0, sizeof(struct digital_atr_req));
  
  	atr_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;
  	atr_req->cmd = DIGITAL_CMD_ATR_REQ;
  	if (target->nfcid2_len)

  		memcpy(atr_req->nfcid3, target->nfcid2, NFC_NFCID2_MAXSIZE);

  	else

  		get_random_bytes(atr_req->nfcid3, NFC_NFCID3_MAXSIZE);

  
  	atr_req->did = 0;
  	atr_req->bs = 0;
  	atr_req->br = 0;

  	ddev->local_payload_max = DIGITAL_PAYLOAD_SIZE_MAX;
  	payload_bits = digital_payload_size_to_bits(ddev->local_payload_max);
  	atr_req->pp = DIGITAL_PAYLOAD_BITS_TO_PP(payload_bits);

  
  	if (gb_len) {
  		atr_req->pp |= DIGITAL_GB_BIT;

  		skb_put_data(skb, gb, gb_len);

  	}
  
  	digital_skb_push_dep_sod(ddev, skb);
  
  	ddev->skb_add_crc(skb);

  	rc = digital_in_send_cmd(ddev, skb, DIGITAL_ATR_RES_RWT,
  				 digital_in_recv_atr_res, target);

  	if (rc)
  		kfree_skb(skb);
  
  	return rc;

  }

  static int digital_in_send_ack(struct nfc_digital_dev *ddev,
  			       struct digital_data_exch *data_exch)
  {
  	struct digital_dep_req_res *dep_req;
  	struct sk_buff *skb;
  	int rc;
  
  	skb = digital_skb_alloc(ddev, 1);
  	if (!skb)
  		return -ENOMEM;
  
  	skb_push(skb, sizeof(struct digital_dep_req_res));
  
  	dep_req = (struct digital_dep_req_res *)skb->data;
  
  	dep_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;
  	dep_req->cmd = DIGITAL_CMD_DEP_REQ;
  	dep_req->pfb = DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU |
  		       ddev->curr_nfc_dep_pni;
  
  	digital_skb_push_dep_sod(ddev, skb);
  
  	ddev->skb_add_crc(skb);

  	ddev->saved_skb = pskb_copy(skb, GFP_KERNEL);

  	rc = digital_in_send_cmd(ddev, skb, ddev->dep_rwt,
  				 digital_in_recv_dep_res, data_exch);

  	if (rc) {

  		kfree_skb(skb);

  		kfree_skb(ddev->saved_skb);
  		ddev->saved_skb = NULL;
  	}

  
  	return rc;
  }

  static int digital_in_send_nack(struct nfc_digital_dev *ddev,
  				struct digital_data_exch *data_exch)
  {
  	struct digital_dep_req_res *dep_req;
  	struct sk_buff *skb;
  	int rc;
  
  	skb = digital_skb_alloc(ddev, 1);
  	if (!skb)
  		return -ENOMEM;
  
  	skb_push(skb, sizeof(struct digital_dep_req_res));
  
  	dep_req = (struct digital_dep_req_res *)skb->data;
  
  	dep_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;
  	dep_req->cmd = DIGITAL_CMD_DEP_REQ;
  	dep_req->pfb = DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU |
  		       DIGITAL_NFC_DEP_PFB_NACK_BIT | ddev->curr_nfc_dep_pni;
  
  	digital_skb_push_dep_sod(ddev, skb);
  
  	ddev->skb_add_crc(skb);

  	rc = digital_in_send_cmd(ddev, skb, ddev->dep_rwt,
  				 digital_in_recv_dep_res, data_exch);

  	if (rc)
  		kfree_skb(skb);
  
  	return rc;
  }

  static int digital_in_send_atn(struct nfc_digital_dev *ddev,
  			       struct digital_data_exch *data_exch)
  {
  	struct digital_dep_req_res *dep_req;
  	struct sk_buff *skb;
  	int rc;
  
  	skb = digital_skb_alloc(ddev, 1);
  	if (!skb)
  		return -ENOMEM;
  
  	skb_push(skb, sizeof(struct digital_dep_req_res));
  
  	dep_req = (struct digital_dep_req_res *)skb->data;
  
  	dep_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;
  	dep_req->cmd = DIGITAL_CMD_DEP_REQ;
  	dep_req->pfb = DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU;
  
  	digital_skb_push_dep_sod(ddev, skb);
  
  	ddev->skb_add_crc(skb);

  	rc = digital_in_send_cmd(ddev, skb, ddev->dep_rwt,
  				 digital_in_recv_dep_res, data_exch);

  	if (rc)
  		kfree_skb(skb);
  
  	return rc;
  }

  static int digital_in_send_rtox(struct nfc_digital_dev *ddev,
  				struct digital_data_exch *data_exch, u8 rtox)
  {
  	struct digital_dep_req_res *dep_req;
  	struct sk_buff *skb;
  	int rc;

  	u16 rwt_int;
  
  	rwt_int = ddev->dep_rwt * rtox;
  	if (rwt_int > digital_rwt_map[DIGITAL_NFC_DEP_IN_MAX_WT])
  		rwt_int = digital_rwt_map[DIGITAL_NFC_DEP_IN_MAX_WT];

  
  	skb = digital_skb_alloc(ddev, 1);
  	if (!skb)
  		return -ENOMEM;

  	skb_put_u8(skb, rtox);

  
  	skb_push(skb, sizeof(struct digital_dep_req_res));
  
  	dep_req = (struct digital_dep_req_res *)skb->data;
  
  	dep_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;
  	dep_req->cmd = DIGITAL_CMD_DEP_REQ;
  	dep_req->pfb = DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU |
  		       DIGITAL_NFC_DEP_PFB_TIMEOUT_BIT;
  
  	digital_skb_push_dep_sod(ddev, skb);
  
  	ddev->skb_add_crc(skb);

  	rc = digital_in_send_cmd(ddev, skb, rwt_int,

  				 digital_in_recv_dep_res, data_exch);

  	if (rc)

  		kfree_skb(skb);

  
  	return rc;
  }

  static int digital_in_send_saved_skb(struct nfc_digital_dev *ddev,
  				     struct digital_data_exch *data_exch)
  {

  	int rc;
  
  	if (!ddev->saved_skb)
  		return -EINVAL;

  	skb_get(ddev->saved_skb);

  	rc = digital_in_send_cmd(ddev, ddev->saved_skb, ddev->dep_rwt,

  				 digital_in_recv_dep_res, data_exch);
  	if (rc)
  		kfree_skb(ddev->saved_skb);
  
  	return rc;

  }

  static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,
  				    struct sk_buff *resp)
  {
  	struct digital_data_exch *data_exch = arg;
  	struct digital_dep_req_res *dep_res;
  	u8 pfb;
  	uint size;
  	int rc;

  	u8 rtox;

  
  	if (IS_ERR(resp)) {
  		rc = PTR_ERR(resp);
  		resp = NULL;

  		if ((rc == -EIO || (rc == -ETIMEDOUT && ddev->nack_count)) &&

  		    (ddev->nack_count++ < DIGITAL_NFC_DEP_N_RETRY_NACK)) {

  			ddev->atn_count = 0;

  			rc = digital_in_send_nack(ddev, data_exch);
  			if (rc)
  				goto error;
  
  			return;

  		} else if ((rc == -ETIMEDOUT) &&
  			   (ddev->atn_count++ < DIGITAL_NFC_DEP_N_RETRY_ATN)) {
  			ddev->nack_count = 0;
  
  			rc = digital_in_send_atn(ddev, data_exch);
  			if (rc)
  				goto error;
  
  			return;

  		}
  
  		goto exit;
  	}
  
  	rc = digital_skb_pull_dep_sod(ddev, resp);
  	if (rc) {
  		PROTOCOL_ERR("14.4.1.2");

  		goto exit;
  	}
  
  	rc = ddev->skb_check_crc(resp);
  	if (rc) {

  		if ((resp->len >= 4) &&
  		    (ddev->nack_count++ < DIGITAL_NFC_DEP_N_RETRY_NACK)) {

  			ddev->atn_count = 0;

  			rc = digital_in_send_nack(ddev, data_exch);
  			if (rc)
  				goto error;
  
  			kfree_skb(resp);
  
  			return;
  		}

  		PROTOCOL_ERR("14.4.1.6");
  		goto error;
  	}

  	ddev->atn_count = 0;

  	ddev->nack_count = 0;

  	if (resp->len > ddev->local_payload_max) {
  		rc = -EMSGSIZE;
  		goto exit;
  	}

  	size = sizeof(struct digital_dep_req_res);

  	dep_res = (struct digital_dep_req_res *)resp->data;

  	if (resp->len < size || dep_res->dir != DIGITAL_NFC_DEP_FRAME_DIR_IN ||

  	    dep_res->cmd != DIGITAL_CMD_DEP_RES) {
  		rc = -EIO;
  		goto error;
  	}
  
  	pfb = dep_res->pfb;

  	if (DIGITAL_NFC_DEP_DID_BIT_SET(pfb)) {
  		PROTOCOL_ERR("14.8.2.1");
  		rc = -EIO;
  		goto error;
  	}

  	if (DIGITAL_NFC_DEP_NAD_BIT_SET(pfb)) {
  		rc = -EIO;
  		goto exit;
  	}

  	if (size > resp->len) {
  		rc = -EIO;
  		goto error;
  	}
  
  	skb_pull(resp, size);

  	switch (DIGITAL_NFC_DEP_PFB_TYPE(pfb)) {
  	case DIGITAL_NFC_DEP_PFB_I_PDU:
  		if (DIGITAL_NFC_DEP_PFB_PNI(pfb) != ddev->curr_nfc_dep_pni) {
  			PROTOCOL_ERR("14.12.3.3");
  			rc = -EIO;
  			goto error;
  		}
  
  		ddev->curr_nfc_dep_pni =
  			DIGITAL_NFC_DEP_PFB_PNI(ddev->curr_nfc_dep_pni + 1);

  		kfree_skb(ddev->saved_skb);
  		ddev->saved_skb = NULL;

  		resp = digital_recv_dep_data_gather(ddev, pfb, resp,
  						    digital_in_send_ack,
  						    data_exch);
  		if (IS_ERR(resp)) {
  			rc = PTR_ERR(resp);
  			resp = NULL;
  			goto error;
  		}
  
  		/* If resp is NULL then we're still chaining so return and
  		 * wait for the next part of the PDU.  Else, the PDU is
  		 * complete so pass it up.
  		 */
  		if (!resp)
  			return;

  		rc = 0;
  		break;
  
  	case DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU:

  		if (DIGITAL_NFC_DEP_NACK_BIT_SET(pfb)) {
  			PROTOCOL_ERR("14.12.4.5");
  			rc = -EIO;
  			goto exit;
  		}

  		if (DIGITAL_NFC_DEP_PFB_PNI(pfb) != ddev->curr_nfc_dep_pni) {
  			PROTOCOL_ERR("14.12.3.3");
  			rc = -EIO;
  			goto exit;
  		}
  
  		ddev->curr_nfc_dep_pni =
  			DIGITAL_NFC_DEP_PFB_PNI(ddev->curr_nfc_dep_pni + 1);

  		if (!ddev->chaining_skb) {
  			PROTOCOL_ERR("14.12.4.3");
  			rc = -EIO;
  			goto exit;
  		}

  		/* The initiator has received a valid ACK. Free the last sent
  		 * PDU and keep on sending chained skb.
  		 */
  		kfree_skb(ddev->saved_skb);
  		ddev->saved_skb = NULL;

  		rc = digital_in_send_dep_req(ddev, NULL,
  					     ddev->chaining_skb,
  					     ddev->data_exch);
  		if (rc)
  			goto error;

  		goto free_resp;

  
  	case DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU:

  		if (!DIGITAL_NFC_DEP_PFB_IS_TIMEOUT(pfb)) { /* ATN */
  			rc = digital_in_send_saved_skb(ddev, data_exch);

  			if (rc)

  				goto error;

  			goto free_resp;

  		}

  		if (ddev->atn_count || ddev->nack_count) {
  			PROTOCOL_ERR("14.12.4.4");
  			rc = -EIO;
  			goto error;
  		}
  
  		rtox = DIGITAL_NFC_DEP_RTOX_VALUE(resp->data[0]);
  		if (!rtox || rtox > DIGITAL_NFC_DEP_RTOX_MAX) {
  			PROTOCOL_ERR("14.8.4.1");
  			rc = -EIO;
  			goto error;
  		}
  
  		rc = digital_in_send_rtox(ddev, data_exch, rtox);

  		if (rc)
  			goto error;

  		goto free_resp;

  	}

  exit:
  	data_exch->cb(data_exch->cb_context, resp, rc);
  
  error:
  	kfree(data_exch);

  	kfree_skb(ddev->chaining_skb);
  	ddev->chaining_skb = NULL;

  	kfree_skb(ddev->saved_skb);
  	ddev->saved_skb = NULL;

  	if (rc)
  		kfree_skb(resp);

  
  	return;
  
  free_resp:
  	dev_kfree_skb(resp);

  }
  
  int digital_in_send_dep_req(struct nfc_digital_dev *ddev,
  			    struct nfc_target *target, struct sk_buff *skb,
  			    struct digital_data_exch *data_exch)
  {
  	struct digital_dep_req_res *dep_req;

  	struct sk_buff *chaining_skb, *tmp_skb;
  	int rc;

  
  	skb_push(skb, sizeof(struct digital_dep_req_res));
  
  	dep_req = (struct digital_dep_req_res *)skb->data;

  	dep_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;
  	dep_req->cmd = DIGITAL_CMD_DEP_REQ;
  	dep_req->pfb = ddev->curr_nfc_dep_pni;

  	ddev->atn_count = 0;

  	ddev->nack_count = 0;

  	chaining_skb = ddev->chaining_skb;

  	tmp_skb = digital_send_dep_data_prep(ddev, skb, dep_req, data_exch);
  	if (IS_ERR(tmp_skb))
  		return PTR_ERR(tmp_skb);

  	digital_skb_push_dep_sod(ddev, tmp_skb);
  
  	ddev->skb_add_crc(tmp_skb);

  	ddev->saved_skb = pskb_copy(tmp_skb, GFP_KERNEL);

  	rc = digital_in_send_cmd(ddev, tmp_skb, ddev->dep_rwt,
  				 digital_in_recv_dep_res, data_exch);

  	if (rc) {
  		if (tmp_skb != skb)
  			kfree_skb(tmp_skb);
  
  		kfree_skb(chaining_skb);
  		ddev->chaining_skb = NULL;

  
  		kfree_skb(ddev->saved_skb);
  		ddev->saved_skb = NULL;

  	}
  
  	return rc;

  }

  static void digital_tg_set_rf_tech(struct nfc_digital_dev *ddev, u8 rf_tech)
  {
  	ddev->curr_rf_tech = rf_tech;
  
  	ddev->skb_add_crc = digital_skb_add_crc_none;
  	ddev->skb_check_crc = digital_skb_check_crc_none;
  
  	if (DIGITAL_DRV_CAPS_TG_CRC(ddev))
  		return;
  
  	switch (ddev->curr_rf_tech) {
  	case NFC_DIGITAL_RF_TECH_106A:
  		ddev->skb_add_crc = digital_skb_add_crc_a;
  		ddev->skb_check_crc = digital_skb_check_crc_a;
  		break;
  
  	case NFC_DIGITAL_RF_TECH_212F:
  	case NFC_DIGITAL_RF_TECH_424F:
  		ddev->skb_add_crc = digital_skb_add_crc_f;
  		ddev->skb_check_crc = digital_skb_check_crc_f;
  		break;
  
  	default:
  		break;
  	}
  }

  static int digital_tg_send_ack(struct nfc_digital_dev *ddev,
  			       struct digital_data_exch *data_exch)
  {
  	struct digital_dep_req_res *dep_res;
  	struct sk_buff *skb;
  	int rc;
  
  	skb = digital_skb_alloc(ddev, 1);
  	if (!skb)
  		return -ENOMEM;
  
  	skb_push(skb, sizeof(struct digital_dep_req_res));
  
  	dep_res = (struct digital_dep_req_res *)skb->data;
  
  	dep_res->dir = DIGITAL_NFC_DEP_FRAME_DIR_IN;
  	dep_res->cmd = DIGITAL_CMD_DEP_RES;
  	dep_res->pfb = DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU |
  		       ddev->curr_nfc_dep_pni;
  
  	if (ddev->did) {
  		dep_res->pfb |= DIGITAL_NFC_DEP_PFB_DID_BIT;

  		skb_put_data(skb, &ddev->did, sizeof(ddev->did));

  	}
  
  	ddev->curr_nfc_dep_pni =
  		DIGITAL_NFC_DEP_PFB_PNI(ddev->curr_nfc_dep_pni + 1);
  
  	digital_skb_push_dep_sod(ddev, skb);
  
  	ddev->skb_add_crc(skb);

  	ddev->saved_skb = pskb_copy(skb, GFP_KERNEL);

  	rc = digital_tg_send_cmd(ddev, skb, 1500, digital_tg_recv_dep_req,
  				 data_exch);

  	if (rc) {

  		kfree_skb(skb);

  		kfree_skb(ddev->saved_skb);
  		ddev->saved_skb = NULL;
  	}

  
  	return rc;
  }

  static int digital_tg_send_atn(struct nfc_digital_dev *ddev)
  {
  	struct digital_dep_req_res *dep_res;
  	struct sk_buff *skb;
  	int rc;
  
  	skb = digital_skb_alloc(ddev, 1);
  	if (!skb)
  		return -ENOMEM;
  
  	skb_push(skb, sizeof(struct digital_dep_req_res));
  
  	dep_res = (struct digital_dep_req_res *)skb->data;
  
  	dep_res->dir = DIGITAL_NFC_DEP_FRAME_DIR_IN;
  	dep_res->cmd = DIGITAL_CMD_DEP_RES;
  	dep_res->pfb = DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU;
  
  	if (ddev->did) {
  		dep_res->pfb |= DIGITAL_NFC_DEP_PFB_DID_BIT;

  		skb_put_data(skb, &ddev->did, sizeof(ddev->did));

  	}
  
  	digital_skb_push_dep_sod(ddev, skb);
  
  	ddev->skb_add_crc(skb);
  
  	rc = digital_tg_send_cmd(ddev, skb, 1500, digital_tg_recv_dep_req,
  				 NULL);
  	if (rc)
  		kfree_skb(skb);
  
  	return rc;
  }

  static int digital_tg_send_saved_skb(struct nfc_digital_dev *ddev)
  {

  	int rc;
  
  	if (!ddev->saved_skb)
  		return -EINVAL;

  	skb_get(ddev->saved_skb);

  	rc = digital_tg_send_cmd(ddev, ddev->saved_skb, 1500,
  				 digital_tg_recv_dep_req, NULL);
  	if (rc)
  		kfree_skb(ddev->saved_skb);
  
  	return rc;

  }

  static void digital_tg_recv_dep_req(struct nfc_digital_dev *ddev, void *arg,
  				    struct sk_buff *resp)
  {
  	int rc;
  	struct digital_dep_req_res *dep_req;

  	u8 pfb;

  	size_t size;
  
  	if (IS_ERR(resp)) {
  		rc = PTR_ERR(resp);
  		resp = NULL;
  		goto exit;
  	}
  
  	rc = ddev->skb_check_crc(resp);
  	if (rc) {
  		PROTOCOL_ERR("14.4.1.6");
  		goto exit;
  	}
  
  	rc = digital_skb_pull_dep_sod(ddev, resp);
  	if (rc) {
  		PROTOCOL_ERR("14.4.1.2");
  		goto exit;
  	}

  	if (resp->len > ddev->local_payload_max) {
  		rc = -EMSGSIZE;
  		goto exit;
  	}

  	size = sizeof(struct digital_dep_req_res);
  	dep_req = (struct digital_dep_req_res *)resp->data;
  
  	if (resp->len < size || dep_req->dir != DIGITAL_NFC_DEP_FRAME_DIR_OUT ||
  	    dep_req->cmd != DIGITAL_CMD_DEP_REQ) {
  		rc = -EIO;
  		goto exit;
  	}

  	pfb = dep_req->pfb;

  	if (DIGITAL_NFC_DEP_DID_BIT_SET(pfb)) {
  		if (ddev->did && (ddev->did == resp->data[3])) {
  			size++;
  		} else {
  			rc = -EIO;
  			goto exit;
  		}
  	} else if (ddev->did) {
  		rc = -EIO;
  		goto exit;
  	}

  	if (DIGITAL_NFC_DEP_NAD_BIT_SET(pfb)) {
  		rc = -EIO;
  		goto exit;
  	}

  	if (size > resp->len) {

  		rc = -EIO;
  		goto exit;
  	}

  	skb_pull(resp, size);
  
  	switch (DIGITAL_NFC_DEP_PFB_TYPE(pfb)) {

  	case DIGITAL_NFC_DEP_PFB_I_PDU:

  		pr_debug("DIGITAL_NFC_DEP_PFB_I_PDU
  ");

  		if (ddev->atn_count) {

  			/* The target has received (and replied to) at least one
  			 * ATN DEP_REQ.
  			 */

  			ddev->atn_count = 0;

  			/* pni of resp PDU equal to the target current pni - 1
  			 * means resp is the previous DEP_REQ PDU received from
  			 * the initiator so the target replies with saved_skb
  			 * which is the previous DEP_RES saved in
  			 * digital_tg_send_dep_res().
  			 */
  			if (DIGITAL_NFC_DEP_PFB_PNI(pfb) ==
  			  DIGITAL_NFC_DEP_PFB_PNI(ddev->curr_nfc_dep_pni - 1)) {
  				rc = digital_tg_send_saved_skb(ddev);
  				if (rc)
  					goto exit;

  				goto free_resp;
  			}
  
  			/* atn_count > 0 and PDU pni != curr_nfc_dep_pni - 1
  			 * means the target probably did not received the last
  			 * DEP_REQ PDU sent by the initiator. The target
  			 * fallbacks to normal processing then.
  			 */
  		}
  
  		if (DIGITAL_NFC_DEP_PFB_PNI(pfb) != ddev->curr_nfc_dep_pni) {
  			PROTOCOL_ERR("14.12.3.4");
  			rc = -EIO;
  			goto exit;

  		}

  		kfree_skb(ddev->saved_skb);
  		ddev->saved_skb = NULL;

  		resp = digital_recv_dep_data_gather(ddev, pfb, resp,
  						    digital_tg_send_ack, NULL);
  		if (IS_ERR(resp)) {
  			rc = PTR_ERR(resp);
  			resp = NULL;
  			goto exit;
  		}
  
  		/* If resp is NULL then we're still chaining so return and
  		 * wait for the next part of the PDU.  Else, the PDU is
  		 * complete so pass it up.
  		 */
  		if (!resp)
  			return;

  		rc = 0;

  		break;
  	case DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU:

  		if (DIGITAL_NFC_DEP_NACK_BIT_SET(pfb)) { /* NACK */
  			if (DIGITAL_NFC_DEP_PFB_PNI(pfb + 1) !=
  						ddev->curr_nfc_dep_pni) {

  				rc = -EIO;
  				goto exit;
  			}

  			ddev->atn_count = 0;
  
  			rc = digital_tg_send_saved_skb(ddev);
  			if (rc)
  				goto exit;
  
  			goto free_resp;
  		}
  
  		/* ACK */
  		if (ddev->atn_count) {
  			/* The target has previously recevied one or more ATN
  			 * PDUs.
  			 */
  			ddev->atn_count = 0;

  			/* If the ACK PNI is equal to the target PNI - 1 means
  			 * that the initiator did not receive the previous PDU
  			 * sent by the target so re-send it.
  			 */
  			if (DIGITAL_NFC_DEP_PFB_PNI(pfb + 1) ==
  						ddev->curr_nfc_dep_pni) {

  				rc = digital_tg_send_saved_skb(ddev);
  				if (rc)
  					goto exit;

  				goto free_resp;

  			}

  			/* Otherwise, the target did not receive the previous
  			 * ACK PDU from the initiator. Fallback to normal
  			 * processing of chained PDU then.
  			 */
  		}

  		/* Keep on sending chained PDU */
  		if (!ddev->chaining_skb ||
  		    DIGITAL_NFC_DEP_PFB_PNI(pfb) !=
  					ddev->curr_nfc_dep_pni) {
  			rc = -EIO;
  			goto exit;
  		}

  		kfree_skb(ddev->saved_skb);
  		ddev->saved_skb = NULL;

  		rc = digital_tg_send_dep_res(ddev, ddev->chaining_skb);
  		if (rc)
  			goto exit;

  		goto free_resp;

  	case DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU:

  		if (DIGITAL_NFC_DEP_PFB_IS_TIMEOUT(pfb)) {
  			rc = -EINVAL;
  			goto exit;
  		}
  
  		rc = digital_tg_send_atn(ddev);
  		if (rc)
  			goto exit;
  
  		ddev->atn_count++;

  		goto free_resp;

  	}

  	rc = nfc_tm_data_received(ddev->nfc_dev, resp);
  
  exit:

  	kfree_skb(ddev->chaining_skb);
  	ddev->chaining_skb = NULL;

  	ddev->atn_count = 0;

  	kfree_skb(ddev->saved_skb);
  	ddev->saved_skb = NULL;

  	if (rc)
  		kfree_skb(resp);

  
  	return;
  
  free_resp:
  	dev_kfree_skb(resp);

  }
  
  int digital_tg_send_dep_res(struct nfc_digital_dev *ddev, struct sk_buff *skb)
  {
  	struct digital_dep_req_res *dep_res;

  	struct sk_buff *chaining_skb, *tmp_skb;
  	int rc;

  
  	skb_push(skb, sizeof(struct digital_dep_req_res));

  	dep_res = (struct digital_dep_req_res *)skb->data;
  
  	dep_res->dir = DIGITAL_NFC_DEP_FRAME_DIR_IN;
  	dep_res->cmd = DIGITAL_CMD_DEP_RES;
  	dep_res->pfb = ddev->curr_nfc_dep_pni;

  	if (ddev->did) {
  		dep_res->pfb |= DIGITAL_NFC_DEP_PFB_DID_BIT;

  		skb_put_data(skb, &ddev->did, sizeof(ddev->did));

  	}

  	ddev->curr_nfc_dep_pni =
  		DIGITAL_NFC_DEP_PFB_PNI(ddev->curr_nfc_dep_pni + 1);

  	chaining_skb = ddev->chaining_skb;

  	tmp_skb = digital_send_dep_data_prep(ddev, skb, dep_res, NULL);
  	if (IS_ERR(tmp_skb))
  		return PTR_ERR(tmp_skb);
  
  	digital_skb_push_dep_sod(ddev, tmp_skb);
  
  	ddev->skb_add_crc(tmp_skb);

  	ddev->saved_skb = pskb_copy(tmp_skb, GFP_KERNEL);

  	rc = digital_tg_send_cmd(ddev, tmp_skb, 1500, digital_tg_recv_dep_req,
  				 NULL);
  	if (rc) {
  		if (tmp_skb != skb)
  			kfree_skb(tmp_skb);
  
  		kfree_skb(chaining_skb);
  		ddev->chaining_skb = NULL;

  
  		kfree_skb(ddev->saved_skb);
  		ddev->saved_skb = NULL;

  	}
  
  	return rc;

  }
  
  static void digital_tg_send_psl_res_complete(struct nfc_digital_dev *ddev,
  					     void *arg, struct sk_buff *resp)
  {

  	u8 rf_tech = (unsigned long)arg;

  
  	if (IS_ERR(resp))
  		return;

  	digital_tg_set_rf_tech(ddev, rf_tech);

  	digital_tg_configure_hw(ddev, NFC_DIGITAL_CONFIG_RF_TECH, rf_tech);
  
  	digital_tg_listen(ddev, 1500, digital_tg_recv_dep_req, NULL);
  
  	dev_kfree_skb(resp);
  }
  
  static int digital_tg_send_psl_res(struct nfc_digital_dev *ddev, u8 did,
  				   u8 rf_tech)
  {
  	struct digital_psl_res *psl_res;
  	struct sk_buff *skb;
  	int rc;
  
  	skb = digital_skb_alloc(ddev, sizeof(struct digital_psl_res));
  	if (!skb)
  		return -ENOMEM;
  
  	skb_put(skb, sizeof(struct digital_psl_res));
  
  	psl_res = (struct digital_psl_res *)skb->data;
  
  	psl_res->dir = DIGITAL_NFC_DEP_FRAME_DIR_IN;
  	psl_res->cmd = DIGITAL_CMD_PSL_RES;
  	psl_res->did = did;
  
  	digital_skb_push_dep_sod(ddev, skb);
  
  	ddev->skb_add_crc(skb);

  	ddev->curr_nfc_dep_pni = 0;

  	rc = digital_tg_send_cmd(ddev, skb, 0, digital_tg_send_psl_res_complete,

  				 (void *)(unsigned long)rf_tech);

  	if (rc)
  		kfree_skb(skb);
  
  	return rc;
  }
  
  static void digital_tg_recv_psl_req(struct nfc_digital_dev *ddev, void *arg,
  				    struct sk_buff *resp)
  {
  	int rc;
  	struct digital_psl_req *psl_req;
  	u8 rf_tech;

  	u8 dsi, payload_size, payload_bits;

  
  	if (IS_ERR(resp)) {
  		rc = PTR_ERR(resp);
  		resp = NULL;
  		goto exit;
  	}
  
  	rc = ddev->skb_check_crc(resp);
  	if (rc) {
  		PROTOCOL_ERR("14.4.1.6");
  		goto exit;
  	}
  
  	rc = digital_skb_pull_dep_sod(ddev, resp);
  	if (rc) {
  		PROTOCOL_ERR("14.4.1.2");
  		goto exit;
  	}
  
  	psl_req = (struct digital_psl_req *)resp->data;
  
  	if (resp->len != sizeof(struct digital_psl_req) ||
  	    psl_req->dir != DIGITAL_NFC_DEP_FRAME_DIR_OUT ||
  	    psl_req->cmd != DIGITAL_CMD_PSL_REQ) {
  		rc = -EIO;
  		goto exit;
  	}
  
  	dsi = (psl_req->brs >> 3) & 0x07;
  	switch (dsi) {
  	case 0:
  		rf_tech = NFC_DIGITAL_RF_TECH_106A;
  		break;
  	case 1:
  		rf_tech = NFC_DIGITAL_RF_TECH_212F;
  		break;
  	case 2:
  		rf_tech = NFC_DIGITAL_RF_TECH_424F;
  		break;
  	default:

  		pr_err("Unsupported dsi value %d
  ", dsi);

  		goto exit;
  	}

  	payload_bits = DIGITAL_PAYLOAD_FSL_TO_BITS(psl_req->fsl);
  	payload_size = digital_payload_bits_to_size(payload_bits);
  
  	if (!payload_size || (payload_size > min(ddev->local_payload_max,
  						 ddev->remote_payload_max))) {
  		rc = -EINVAL;
  		goto exit;
  	}
  
  	ddev->local_payload_max = payload_size;
  	ddev->remote_payload_max = payload_size;

  	rc = digital_tg_send_psl_res(ddev, psl_req->did, rf_tech);
  
  exit:
  	kfree_skb(resp);
  }
  
  static void digital_tg_send_atr_res_complete(struct nfc_digital_dev *ddev,
  					     void *arg, struct sk_buff *resp)
  {
  	int offset;
  
  	if (IS_ERR(resp)) {
  		digital_poll_next_tech(ddev);
  		return;
  	}
  
  	offset = 2;
  	if (resp->data[0] == DIGITAL_NFC_DEP_NFCA_SOD_SB)
  		offset++;

  	ddev->atn_count = 0;

  	if (resp->data[offset] == DIGITAL_CMD_PSL_REQ)
  		digital_tg_recv_psl_req(ddev, arg, resp);
  	else
  		digital_tg_recv_dep_req(ddev, arg, resp);
  }
  
  static int digital_tg_send_atr_res(struct nfc_digital_dev *ddev,
  				   struct digital_atr_req *atr_req)
  {
  	struct digital_atr_res *atr_res;
  	struct sk_buff *skb;

  	u8 *gb, payload_bits;

  	size_t gb_len;
  	int rc;
  
  	gb = nfc_get_local_general_bytes(ddev->nfc_dev, &gb_len);
  	if (!gb)
  		gb_len = 0;
  
  	skb = digital_skb_alloc(ddev, sizeof(struct digital_atr_res) + gb_len);
  	if (!skb)
  		return -ENOMEM;
  
  	skb_put(skb, sizeof(struct digital_atr_res));
  	atr_res = (struct digital_atr_res *)skb->data;
  
  	memset(atr_res, 0, sizeof(struct digital_atr_res));
  
  	atr_res->dir = DIGITAL_NFC_DEP_FRAME_DIR_IN;
  	atr_res->cmd = DIGITAL_CMD_ATR_RES;
  	memcpy(atr_res->nfcid3, atr_req->nfcid3, sizeof(atr_req->nfcid3));

  	atr_res->to = DIGITAL_NFC_DEP_TG_MAX_WT;

  
  	ddev->local_payload_max = DIGITAL_PAYLOAD_SIZE_MAX;
  	payload_bits = digital_payload_size_to_bits(ddev->local_payload_max);
  	atr_res->pp = DIGITAL_PAYLOAD_BITS_TO_PP(payload_bits);

  	if (gb_len) {
  		skb_put(skb, gb_len);
  
  		atr_res->pp |= DIGITAL_GB_BIT;
  		memcpy(atr_res->gb, gb, gb_len);
  	}
  
  	digital_skb_push_dep_sod(ddev, skb);
  
  	ddev->skb_add_crc(skb);

  	ddev->curr_nfc_dep_pni = 0;

  	rc = digital_tg_send_cmd(ddev, skb, 999,
  				 digital_tg_send_atr_res_complete, NULL);

  	if (rc)

  		kfree_skb(skb);

  
  	return rc;
  }
  
  void digital_tg_recv_atr_req(struct nfc_digital_dev *ddev, void *arg,
  			     struct sk_buff *resp)
  {
  	int rc;
  	struct digital_atr_req *atr_req;
  	size_t gb_len, min_size;

  	u8 poll_tech_count, payload_bits;

  
  	if (IS_ERR(resp)) {
  		rc = PTR_ERR(resp);
  		resp = NULL;
  		goto exit;
  	}
  
  	if (!resp->len) {
  		rc = -EIO;
  		goto exit;
  	}
  
  	if (resp->data[0] == DIGITAL_NFC_DEP_NFCA_SOD_SB) {
  		min_size = DIGITAL_ATR_REQ_MIN_SIZE + 2;

  		digital_tg_set_rf_tech(ddev, NFC_DIGITAL_RF_TECH_106A);

  	} else {
  		min_size = DIGITAL_ATR_REQ_MIN_SIZE + 1;

  		digital_tg_set_rf_tech(ddev, NFC_DIGITAL_RF_TECH_212F);

  	}
  
  	if (resp->len < min_size) {
  		rc = -EIO;
  		goto exit;
  	}

  	ddev->curr_protocol = NFC_PROTO_NFC_DEP_MASK;

  
  	rc = ddev->skb_check_crc(resp);
  	if (rc) {
  		PROTOCOL_ERR("14.4.1.6");
  		goto exit;
  	}
  
  	rc = digital_skb_pull_dep_sod(ddev, resp);
  	if (rc) {
  		PROTOCOL_ERR("14.4.1.2");
  		goto exit;
  	}
  
  	atr_req = (struct digital_atr_req *)resp->data;
  
  	if (atr_req->dir != DIGITAL_NFC_DEP_FRAME_DIR_OUT ||

  	    atr_req->cmd != DIGITAL_CMD_ATR_REQ ||
  	    atr_req->did > DIGITAL_DID_MAX) {

  		rc = -EINVAL;
  		goto exit;
  	}

  	payload_bits = DIGITAL_PAYLOAD_PP_TO_BITS(atr_req->pp);
  	ddev->remote_payload_max = digital_payload_bits_to_size(payload_bits);
  
  	if (!ddev->remote_payload_max) {
  		rc = -EINVAL;
  		goto exit;
  	}

  	ddev->did = atr_req->did;

  	rc = digital_tg_configure_hw(ddev, NFC_DIGITAL_CONFIG_FRAMING,
  				     NFC_DIGITAL_FRAMING_NFC_DEP_ACTIVATED);
  	if (rc)
  		goto exit;
  
  	rc = digital_tg_send_atr_res(ddev, atr_req);
  	if (rc)
  		goto exit;
  
  	gb_len = resp->len - sizeof(struct digital_atr_req);

  
  	poll_tech_count = ddev->poll_tech_count;
  	ddev->poll_tech_count = 0;

  	rc = nfc_tm_activated(ddev->nfc_dev, NFC_PROTO_NFC_DEP_MASK,
  			      NFC_COMM_PASSIVE, atr_req->gb, gb_len);

  	if (rc) {
  		ddev->poll_tech_count = poll_tech_count;

  		goto exit;

  	}

  
  	rc = 0;
  exit:
  	if (rc)
  		digital_poll_next_tech(ddev);
  
  	dev_kfree_skb(resp);
  }