1 files changed, 763 insertions, 71 deletions

diff --git a/net/nfc/digital_dep.c b/net/nfc/digital_dep.c
index b60aa35c074f..f72be7433df3 100644
--- a/net/nfc/digital_dep.c
+++ b/net/nfc/digital_dep.c
@@ -17,6 +17,9 @@
 
 #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
 
@@ -32,20 +35,32 @@
 #define DIGITAL_ATR_REQ_MIN_SIZE 16
 #define DIGITAL_ATR_REQ_MAX_SIZE 64
 
-#define DIGITAL_LR_BITS_PAYLOAD_SIZE_254B 0x30
-#define DIGITAL_FSL_BITS_PAYLOAD_SIZE_254B \
-				(DIGITAL_LR_BITS_PAYLOAD_SIZE_254B >> 4)
+#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) & 0x10)
+#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) & 0x04)
+#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_PFB_I_PDU          0x00
@@ -97,6 +112,34 @@ struct digital_dep_req_res {
 
 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
+};
+
+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)
@@ -129,6 +172,106 @@ static int digital_skb_pull_dep_sod(struct nfc_digital_dev *ddev,
 	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_reserve(new_skb, ddev->tx_headroom + NFC_HEADER_SIZE +
+					DIGITAL_NFC_DEP_REQ_RES_HEADROOM);
+		memcpy(skb_put(new_skb, ddev->remote_payload_max), 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;
+		}
+
+		memcpy(skb_put(ddev->chaining_skb, resp->len), 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)
 {
@@ -198,6 +341,8 @@ static int digital_in_send_psl_req(struct nfc_digital_dev *ddev,
 {
 	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)
@@ -211,14 +356,24 @@ static int digital_in_send_psl_req(struct nfc_digital_dev *ddev,
 	psl_req->cmd = DIGITAL_CMD_PSL_REQ;
 	psl_req->did = 0;
 	psl_req->brs = (0x2 << 3) | 0x2; /* 424F both directions */
-	psl_req->fsl = DIGITAL_FSL_BITS_PAYLOAD_SIZE_254B;
+
+	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);
 
-	return digital_in_send_cmd(ddev, skb, 500, digital_in_recv_psl_res,
-				   target);
+	rc = digital_in_send_cmd(ddev, skb, 500, 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,
@@ -226,7 +381,7 @@ static void digital_in_recv_atr_res(struct nfc_digital_dev *ddev, void *arg,
 {
 	struct nfc_target *target = arg;
 	struct digital_atr_res *atr_res;
-	u8 gb_len;
+	u8 gb_len, payload_bits;
 	int rc;
 
 	if (IS_ERR(resp)) {
@@ -256,6 +411,14 @@ static void digital_in_recv_atr_res(struct nfc_digital_dev *ddev, void *arg,
 
 	atr_res = (struct digital_atr_res *)resp->data;
 
+	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;
@@ -286,6 +449,8 @@ int digital_in_send_atr_req(struct nfc_digital_dev *ddev,
 	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;
 
@@ -314,7 +479,9 @@ int digital_in_send_atr_req(struct nfc_digital_dev *ddev,
 	atr_req->bs = 0;
 	atr_req->br = 0;
 
-	atr_req->pp = DIGITAL_LR_BITS_PAYLOAD_SIZE_254B;
+	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;
@@ -325,8 +492,113 @@ int digital_in_send_atr_req(struct nfc_digital_dev *ddev,
 
 	ddev->skb_add_crc(skb);
 
-	return digital_in_send_cmd(ddev, skb, 500, digital_in_recv_atr_res,
-				   target);
+	rc = digital_in_send_cmd(ddev, skb, 500, 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 = skb_get(skb);
+	ddev->saved_skb_len = skb->len;
+
+	rc = digital_in_send_cmd(ddev, skb, 1500, 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, 1500, 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, 1500, 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,
@@ -355,12 +627,30 @@ static int digital_in_send_rtox(struct nfc_digital_dev *ddev,
 
 	ddev->skb_add_crc(skb);
 
+	ddev->saved_skb = skb_get(skb);
+	ddev->saved_skb_len = skb->len;
+
 	rc = digital_in_send_cmd(ddev, skb, 1500, 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_saved_skb(struct nfc_digital_dev *ddev,
+				     struct digital_data_exch *data_exch)
+{
+	skb_get(ddev->saved_skb);
+	skb_push(ddev->saved_skb, ddev->saved_skb_len);
+
+	return digital_in_send_cmd(ddev, ddev->saved_skb, 1500,
+				   digital_in_recv_dep_res, data_exch);
+}
+
 static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,
 				    struct sk_buff *resp)
 {
@@ -373,25 +663,67 @@ static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,
 	if (IS_ERR(resp)) {
 		rc = PTR_ERR(resp);
 		resp = NULL;
+
+		if (((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;
 	}
 
-	rc = digital_skb_pull_dep_sod(ddev, resp);
-	if (rc) {
-		PROTOCOL_ERR("14.4.1.2");
+	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 < sizeof(struct digital_dep_req_res) ||
-	    dep_res->dir != DIGITAL_NFC_DEP_FRAME_DIR_IN ||
+	if (resp->len < size || dep_res->dir != DIGITAL_NFC_DEP_FRAME_DIR_IN ||
 	    dep_res->cmd != DIGITAL_CMD_DEP_RES) {
 		rc = -EIO;
 		goto error;
@@ -399,6 +731,24 @@ static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,
 
 	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) {
@@ -409,21 +759,71 @@ static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,
 
 		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_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 && !DIGITAL_NFC_DEP_NACK_BIT_SET(pfb)) {
+			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;
+
+			return;
+		}
+
 		pr_err("Received a ACK/NACK PDU\n");
-		rc = -EIO;
-		goto error;
+		rc = -EINVAL;
+		goto exit;
 
 	case DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU:
-		if (!DIGITAL_NFC_DEP_PFB_IS_TIMEOUT(pfb)) {
-			rc = -EINVAL;
-			goto error;
+		if (!DIGITAL_NFC_DEP_PFB_IS_TIMEOUT(pfb)) { /* ATN */
+			rc = digital_in_send_saved_skb(ddev, data_exch);
+			if (rc) {
+				kfree_skb(ddev->saved_skb);
+				goto error;
+			}
+
+			return;
 		}
 
-		rc = digital_in_send_rtox(ddev, data_exch, resp->data[3]);
+		kfree_skb(ddev->saved_skb);
+		ddev->saved_skb = NULL;
+
+		rc = digital_in_send_rtox(ddev, data_exch, resp->data[0]);
 		if (rc)
 			goto error;
 
@@ -431,30 +831,18 @@ static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,
 		return;
 	}
 
-	if (DIGITAL_NFC_DEP_MI_BIT_SET(pfb)) {
-		pr_err("MI bit set. Chained PDU not supported\n");
-		rc = -EIO;
-		goto error;
-	}
-
-	size = sizeof(struct digital_dep_req_res);
-
-	if (DIGITAL_NFC_DEP_DID_BIT_SET(pfb))
-		size++;
-
-	if (size > resp->len) {
-		rc = -EIO;
-		goto error;
-	}
-
-	skb_pull(resp, size);
-
 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);
 }
@@ -464,20 +852,47 @@ int digital_in_send_dep_req(struct nfc_digital_dev *ddev,
 			    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;
 
-	digital_skb_push_dep_sod(ddev, skb);
+	ddev->atn_count = 0;
+	ddev->nack_count = 0;
 
-	ddev->skb_add_crc(skb);
+	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);
 
-	return digital_in_send_cmd(ddev, skb, 1500, digital_in_recv_dep_res,
-				   data_exch);
+	ddev->saved_skb = skb_get(tmp_skb);
+	ddev->saved_skb_len = tmp_skb->len;
+
+	rc = digital_in_send_cmd(ddev, tmp_skb, 1500, 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)
@@ -507,11 +922,106 @@ static void digital_tg_set_rf_tech(struct nfc_digital_dev *ddev, u8 rf_tech)
 	}
 }
 
+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;
+
+		memcpy(skb_put(skb, sizeof(ddev->did)), &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 = skb_get(skb);
+	ddev->saved_skb_len = skb->len;
+
+	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;
+
+		memcpy(skb_put(skb, sizeof(ddev->did)), &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)
+{
+	skb_get(ddev->saved_skb);
+	skb_push(ddev->saved_skb, ddev->saved_skb_len);
+
+	return digital_tg_send_cmd(ddev, ddev->saved_skb, 1500,
+				   digital_tg_recv_dep_req, NULL);
+}
+
 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)) {
@@ -532,6 +1042,11 @@ static void digital_tg_recv_dep_req(struct nfc_digital_dev *ddev, void *arg,
 		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;
 
@@ -541,34 +1056,147 @@ static void digital_tg_recv_dep_req(struct nfc_digital_dev *ddev, void *arg,
 		goto exit;
 	}
 
-	if (DIGITAL_NFC_DEP_DID_BIT_SET(dep_req->pfb))
-		size++;
+	pfb = dep_req->pfb;
 
-	if (resp->len < size) {
+	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;
 	}
 
-	switch (DIGITAL_NFC_DEP_PFB_TYPE(dep_req->pfb)) {
+	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");
-		ddev->curr_nfc_dep_pni = DIGITAL_NFC_DEP_PFB_PNI(dep_req->pfb);
+
+		if ((ddev->atn_count && (DIGITAL_NFC_DEP_PFB_PNI(pfb - 1) !=
+						ddev->curr_nfc_dep_pni)) ||
+		    (DIGITAL_NFC_DEP_PFB_PNI(pfb) != ddev->curr_nfc_dep_pni)) {
+			PROTOCOL_ERR("14.12.3.4");
+			rc = -EIO;
+			goto exit;
+		}
+
+		if (ddev->atn_count) {
+			ddev->atn_count = 0;
+
+			rc = digital_tg_send_saved_skb(ddev);
+			if (rc)
+				goto exit;
+
+			return;
+		}
+
+		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:
-		pr_err("Received a ACK/NACK PDU\n");
-		rc = -EINVAL;
-		goto exit;
+		if (!DIGITAL_NFC_DEP_NACK_BIT_SET(pfb)) { /* ACK */
+			if ((ddev->atn_count &&
+			     (DIGITAL_NFC_DEP_PFB_PNI(pfb - 1) !=
+						ddev->curr_nfc_dep_pni)) ||
+			    (DIGITAL_NFC_DEP_PFB_PNI(pfb) !=
+						ddev->curr_nfc_dep_pni) ||
+			    !ddev->chaining_skb || !ddev->saved_skb) {
+				rc = -EIO;
+				goto exit;
+			}
+
+			if (ddev->atn_count) {
+				ddev->atn_count = 0;
+
+				rc = digital_tg_send_saved_skb(ddev);
+				if (rc)
+					goto exit;
+
+				return;
+			}
+
+			kfree_skb(ddev->saved_skb);
+			ddev->saved_skb = NULL;
+
+			rc = digital_tg_send_dep_res(ddev, ddev->chaining_skb);
+			if (rc)
+				goto exit;
+		} else { /* NACK */
+			if ((DIGITAL_NFC_DEP_PFB_PNI(pfb + 1) !=
+						ddev->curr_nfc_dep_pni) ||
+			    !ddev->saved_skb) {
+				rc = -EIO;
+				goto exit;
+			}
+
+			ddev->atn_count = 0;
+
+			rc = digital_tg_send_saved_skb(ddev);
+			if (rc) {
+				kfree_skb(ddev->saved_skb);
+				goto exit;
+			}
+		}
+
+		return;
 	case DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU:
-		pr_err("Received a SUPERVISOR PDU\n");
-		rc = -EINVAL;
-		goto exit;
-	}
+		if (DIGITAL_NFC_DEP_PFB_IS_TIMEOUT(pfb)) {
+			rc = -EINVAL;
+			goto exit;
+		}
 
-	skb_pull(resp, size);
+		rc = digital_tg_send_atn(ddev);
+		if (rc)
+			goto exit;
+
+		ddev->atn_count++;
+
+		kfree_skb(resp);
+		return;
+	}
 
 	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);
 }
@@ -576,20 +1204,54 @@ exit:
 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;
 
-	digital_skb_push_dep_sod(ddev, skb);
+	if (ddev->did) {
+		dep_res->pfb |= DIGITAL_NFC_DEP_PFB_DID_BIT;
 
-	ddev->skb_add_crc(skb);
+		memcpy(skb_put(skb, sizeof(ddev->did)), &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 = skb_get(tmp_skb);
+	ddev->saved_skb_len = tmp_skb->len;
+
+	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;
 
-	return digital_tg_send_cmd(ddev, skb, 1500, digital_tg_recv_dep_req,
-				   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,
@@ -632,9 +1294,10 @@ static int digital_tg_send_psl_res(struct nfc_digital_dev *ddev, u8 did,
 
 	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);
 
@@ -647,7 +1310,7 @@ static void digital_tg_recv_psl_req(struct nfc_digital_dev *ddev, void *arg,
 	int rc;
 	struct digital_psl_req *psl_req;
 	u8 rf_tech;
-	u8 dsi;
+	u8 dsi, payload_size, payload_bits;
 
 	if (IS_ERR(resp)) {
 		rc = PTR_ERR(resp);
@@ -692,6 +1355,18 @@ static void digital_tg_recv_psl_req(struct nfc_digital_dev *ddev, void *arg,
 		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:
@@ -712,6 +1387,8 @@ static void digital_tg_send_atr_res_complete(struct nfc_digital_dev *ddev,
 	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
@@ -723,7 +1400,7 @@ static int digital_tg_send_atr_res(struct nfc_digital_dev *ddev,
 {
 	struct digital_atr_res *atr_res;
 	struct sk_buff *skb;
-	u8 *gb;
+	u8 *gb, payload_bits;
 	size_t gb_len;
 	int rc;
 
@@ -744,7 +1421,11 @@ static int digital_tg_send_atr_res(struct nfc_digital_dev *ddev,
 	atr_res->cmd = DIGITAL_CMD_ATR_RES;
 	memcpy(atr_res->nfcid3, atr_req->nfcid3, sizeof(atr_req->nfcid3));
 	atr_res->to = 8;
-	atr_res->pp = DIGITAL_LR_BITS_PAYLOAD_SIZE_254B;
+
+	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);
 
@@ -756,12 +1437,12 @@ static int digital_tg_send_atr_res(struct nfc_digital_dev *ddev,
 
 	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) {
+	if (rc)
 		kfree_skb(skb);
-		return rc;
-	}
 
 	return rc;
 }
@@ -772,7 +1453,7 @@ void digital_tg_recv_atr_req(struct nfc_digital_dev *ddev, void *arg,
 	int rc;
 	struct digital_atr_req *atr_req;
 	size_t gb_len, min_size;
-	u8 poll_tech_count;
+	u8 poll_tech_count, payload_bits;
 
 	if (IS_ERR(resp)) {
 		rc = PTR_ERR(resp);
@@ -815,11 +1496,22 @@ void digital_tg_recv_atr_req(struct nfc_digital_dev *ddev, void *arg,
 	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->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)