Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1645 insertions, 0 deletions

diff --git a/net/nfc/digital_dep.c b/net/nfc/digital_dep.c
new file mode 100644
index 000000000..1eed0cf59
--- /dev/null
+++ b/net/nfc/digital_dep.c
@@ -0,0 +1,1645 @@
+/*
+ * 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\n");
+
+		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);
+	if (rc)
+		resp = NULL;
+
+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\n", 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);
+}