NFC: nci: Add dynamic logical connections support

The current NCI core only support the RF static connection.
For other NFC features such as Secure Element communication, we
may need to create logical connections to the NFCEE (Execution
Environment.

In order to track each logical connection ID dynamically, we add a
linked list of connection info pointers to the nci_dev structure.

Signed-off-by: Christophe Ricard <[email protected]>
Signed-off-by: Samuel Ortiz <[email protected]>

Author: cricard13

include/net/nfc/nci_core.h

@@ -82,6 +82,23 @@ struct nci_ops {
 
 #define NCI_MAX_SUPPORTED_RF_INTERFACES		4
 #define NCI_MAX_DISCOVERED_TARGETS		10
+#define NCI_MAX_NUM_NFCEE   255
+#define NCI_MAX_CONN_ID		7
+
+struct nci_conn_info {
+	struct list_head list;
+	__u8	id; /* can be an RF Discovery ID or an NFCEE ID */
+	__u8	conn_id;
+	__u8	max_pkt_payload_len;
+
+	atomic_t credits_cnt;
+	__u8	 initial_num_credits;
+
+	data_exchange_cb_t	data_exchange_cb;
+	void *data_exchange_cb_context;
+
+	struct sk_buff *rx_skb;
+};
 
 /* NCI Core structures */
 struct nci_dev {
@@ -95,7 +112,9 @@ struct nci_dev {
 	unsigned long		flags;
 
 	atomic_t		cmd_cnt;
-	atomic_t		credits_cnt;
+	__u8			cur_conn_id;
+
+	struct list_head	conn_info_list;
 
 	struct timer_list	cmd_timer;
 	struct timer_list	data_timer;
@@ -141,13 +160,10 @@ struct nci_dev {
 	__u8			manufact_id;
 	__u32			manufact_specific_info;
 
-	/* received during NCI_OP_RF_INTF_ACTIVATED_NTF */
-	__u8			max_data_pkt_payload_size;
-	__u8			initial_num_credits;
+	/* Save RF Discovery ID or NFCEE ID under conn_create */
+	__u8			cur_id;
 
 	/* stored during nci_data_exchange */
-	data_exchange_cb_t	data_exchange_cb;
-	void			*data_exchange_cb_context;
 	struct sk_buff		*rx_data_reassembly;
 
 	/* stored during intf_activated_ntf */
@@ -200,7 +216,7 @@ void nci_rx_data_packet(struct nci_dev *ndev, struct sk_buff *skb);
 int nci_send_cmd(struct nci_dev *ndev, __u16 opcode, __u8 plen, void *payload);
 int nci_send_data(struct nci_dev *ndev, __u8 conn_id, struct sk_buff *skb);
 void nci_data_exchange_complete(struct nci_dev *ndev, struct sk_buff *skb,
-				int err);
+				__u8 conn_id, int err);
 void nci_clear_target_list(struct nci_dev *ndev);
 
 /* ----- NCI requests ----- */
@@ -209,6 +225,8 @@ void nci_clear_target_list(struct nci_dev *ndev);
 #define NCI_REQ_CANCELED	2
 
 void nci_req_complete(struct nci_dev *ndev, int result);
+struct nci_conn_info *nci_get_conn_info_by_conn_id(struct nci_dev *ndev,
+						   int conn_id);
 
 /* ----- NCI status code ----- */
 int nci_to_errno(__u8 code);

net/nfc/nci/core.c

@@ -45,6 +45,19 @@ static void nci_cmd_work(struct work_struct *work);
 static void nci_rx_work(struct work_struct *work);
 static void nci_tx_work(struct work_struct *work);
 
+struct nci_conn_info *nci_get_conn_info_by_conn_id(struct nci_dev *ndev,
+						   int conn_id)
+{
+	struct nci_conn_info *conn_info;
+
+	list_for_each_entry(conn_info, &ndev->conn_info_list, list) {
+		if (conn_info->conn_id == conn_id)
+			return conn_info;
+	}
+
+	return NULL;
+}
+
 /* ---- NCI requests ---- */
 
 void nci_req_complete(struct nci_dev *ndev, int result)
@@ -712,6 +725,11 @@ static int nci_transceive(struct nfc_dev *nfc_dev, struct nfc_target *target,
 {
 	struct nci_dev *ndev = nfc_get_drvdata(nfc_dev);
 	int rc;
+	struct nci_conn_info    *conn_info;
+
+	conn_info = nci_get_conn_info_by_conn_id(ndev, NCI_STATIC_RF_CONN_ID);
+	if (!conn_info)
+		return -EPROTO;
 
 	pr_debug("target_idx %d, len %d\n", target->idx, skb->len);
 
@@ -724,8 +742,8 @@ static int nci_transceive(struct nfc_dev *nfc_dev, struct nfc_target *target,
 		return -EBUSY;
 
 	/* store cb and context to be used on receiving data */
-	ndev->data_exchange_cb = cb;
-	ndev->data_exchange_cb_context = cb_context;
+	conn_info->data_exchange_cb = cb;
+	conn_info->data_exchange_cb_context = cb_context;
 
 	rc = nci_send_data(ndev, NCI_STATIC_RF_CONN_ID, skb);
 	if (rc)
@@ -913,6 +931,7 @@ int nci_register_device(struct nci_dev *ndev)
 		    (unsigned long) ndev);
 
 	mutex_init(&ndev->req_lock);
+	INIT_LIST_HEAD(&ndev->conn_info_list);
 
 	rc = nfc_register_device(ndev->nfc_dev);
 	if (rc)
@@ -938,12 +957,19 @@ EXPORT_SYMBOL(nci_register_device);
  */
 void nci_unregister_device(struct nci_dev *ndev)
 {
+	struct nci_conn_info    *conn_info, *n;
+
 	nci_close_device(ndev);
 
 	destroy_workqueue(ndev->cmd_wq);
 	destroy_workqueue(ndev->rx_wq);
 	destroy_workqueue(ndev->tx_wq);
 
+	list_for_each_entry_safe(conn_info, n, &ndev->conn_info_list, list) {
+		list_del(&conn_info->list);
+		/* conn_info is allocated with devm_kzalloc */
+	}
+
 	nfc_unregister_device(ndev->nfc_dev);
 }
 EXPORT_SYMBOL(nci_unregister_device);
@@ -1027,20 +1053,25 @@ int nci_send_cmd(struct nci_dev *ndev, __u16 opcode, __u8 plen, void *payload)
 static void nci_tx_work(struct work_struct *work)
 {
 	struct nci_dev *ndev = container_of(work, struct nci_dev, tx_work);
+	struct nci_conn_info    *conn_info;
 	struct sk_buff *skb;
 
-	pr_debug("credits_cnt %d\n", atomic_read(&ndev->credits_cnt));
+	conn_info = nci_get_conn_info_by_conn_id(ndev, ndev->cur_conn_id);
+	if (!conn_info)
+		return;
+
+	pr_debug("credits_cnt %d\n", atomic_read(&conn_info->credits_cnt));
 
 	/* Send queued tx data */
-	while (atomic_read(&ndev->credits_cnt)) {
+	while (atomic_read(&conn_info->credits_cnt)) {
 		skb = skb_dequeue(&ndev->tx_q);
 		if (!skb)
 			return;
 
 		/* Check if data flow control is used */
-		if (atomic_read(&ndev->credits_cnt) !=
+		if (atomic_read(&conn_info->credits_cnt) !=
 		    NCI_DATA_FLOW_CONTROL_NOT_USED)
-			atomic_dec(&ndev->credits_cnt);
+			atomic_dec(&conn_info->credits_cnt);
 
 		pr_debug("NCI TX: MT=data, PBF=%d, conn_id=%d, plen=%d\n",
 			 nci_pbf(skb->data),
@@ -1092,7 +1123,9 @@ static void nci_rx_work(struct work_struct *work)
 	if (test_bit(NCI_DATA_EXCHANGE_TO, &ndev->flags)) {
 		/* complete the data exchange transaction, if exists */
 		if (test_bit(NCI_DATA_EXCHANGE, &ndev->flags))
-			nci_data_exchange_complete(ndev, NULL, -ETIMEDOUT);
+			nci_data_exchange_complete(ndev, NULL,
+						   ndev->cur_conn_id,
+						   -ETIMEDOUT);
 
 		clear_bit(NCI_DATA_EXCHANGE_TO, &ndev->flags);
 	}

net/nfc/nci/data.c

@@ -36,10 +36,20 @@
 
 /* Complete data exchange transaction and forward skb to nfc core */
 void nci_data_exchange_complete(struct nci_dev *ndev, struct sk_buff *skb,
-				int err)
+				__u8 conn_id, int err)
 {
-	data_exchange_cb_t cb = ndev->data_exchange_cb;
-	void *cb_context = ndev->data_exchange_cb_context;
+	struct nci_conn_info    *conn_info;
+	data_exchange_cb_t cb;
+	void *cb_context;
+
+	conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
+	if (!conn_info) {
+		kfree_skb(skb);
+		goto exit;
+	}
+
+	cb = conn_info->data_exchange_cb;
+	cb_context = conn_info->data_exchange_cb_context;
 
 	pr_debug("len %d, err %d\n", skb ? skb->len : 0, err);
 
@@ -48,9 +58,6 @@ void nci_data_exchange_complete(struct nci_dev *ndev, struct sk_buff *skb,
 	clear_bit(NCI_DATA_EXCHANGE_TO, &ndev->flags);
 
 	if (cb) {
-		ndev->data_exchange_cb = NULL;
-		ndev->data_exchange_cb_context = NULL;
-
 		/* forward skb to nfc core */
 		cb(cb_context, skb, err);
 	} else if (skb) {
@@ -60,6 +67,7 @@ void nci_data_exchange_complete(struct nci_dev *ndev, struct sk_buff *skb,
 		kfree_skb(skb);
 	}
 
+exit:
 	clear_bit(NCI_DATA_EXCHANGE, &ndev->flags);
 }
 
@@ -85,6 +93,7 @@ static inline void nci_push_data_hdr(struct nci_dev *ndev,
 static int nci_queue_tx_data_frags(struct nci_dev *ndev,
 				   __u8 conn_id,
 				   struct sk_buff *skb) {
+	struct nci_conn_info    *conn_info;
 	int total_len = skb->len;
 	unsigned char *data = skb->data;
 	unsigned long flags;
@@ -95,11 +104,17 @@ static int nci_queue_tx_data_frags(struct nci_dev *ndev,
 
 	pr_debug("conn_id 0x%x, total_len %d\n", conn_id, total_len);
 
+	conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
+	if (!conn_info) {
+		rc = -EPROTO;
+		goto free_exit;
+	}
+
 	__skb_queue_head_init(&frags_q);
 
 	while (total_len) {
 		frag_len =
-			min_t(int, total_len, ndev->max_data_pkt_payload_size);
+			min_t(int, total_len, conn_info->max_pkt_payload_len);
 
 		skb_frag = nci_skb_alloc(ndev,
 					 (NCI_DATA_HDR_SIZE + frag_len),
@@ -151,12 +166,19 @@ static int nci_queue_tx_data_frags(struct nci_dev *ndev,
 /* Send NCI data */
 int nci_send_data(struct nci_dev *ndev, __u8 conn_id, struct sk_buff *skb)
 {
+	struct nci_conn_info    *conn_info;
 	int rc = 0;
 
 	pr_debug("conn_id 0x%x, plen %d\n", conn_id, skb->len);
 
+	conn_info = nci_get_conn_info_by_conn_id(ndev, conn_id);
+	if (!conn_info) {
+		rc = -EPROTO;
+		goto free_exit;
+	}
+
 	/* check if the packet need to be fragmented */
-	if (skb->len <= ndev->max_data_pkt_payload_size) {
+	if (skb->len <= conn_info->max_pkt_payload_len) {
 		/* no need to fragment packet */
 		nci_push_data_hdr(ndev, conn_id, skb, NCI_PBF_LAST);
 
@@ -170,6 +192,7 @@ int nci_send_data(struct nci_dev *ndev, __u8 conn_id, struct sk_buff *skb)
 		}
 	}
 
+	ndev->cur_conn_id = conn_id;
 	queue_work(ndev->tx_wq, &ndev->tx_work);
 
 	goto exit;
@@ -185,7 +208,7 @@ int nci_send_data(struct nci_dev *ndev, __u8 conn_id, struct sk_buff *skb)
 
 static void nci_add_rx_data_frag(struct nci_dev *ndev,
 				 struct sk_buff *skb,
-				 __u8 pbf, __u8 status)
+				 __u8 pbf, __u8 conn_id, __u8 status)
 {
 	int reassembly_len;
 	int err = 0;
@@ -229,16 +252,13 @@ static void nci_add_rx_data_frag(struct nci_dev *ndev,
 	}
 
 exit:
-	if (ndev->nfc_dev->rf_mode == NFC_RF_INITIATOR) {
-		nci_data_exchange_complete(ndev, skb, err);
-	} else if (ndev->nfc_dev->rf_mode == NFC_RF_TARGET) {
+	if (ndev->nfc_dev->rf_mode == NFC_RF_TARGET) {
 		/* Data received in Target mode, forward to nfc core */
 		err = nfc_tm_data_received(ndev->nfc_dev, skb);
 		if (err)
 			pr_err("unable to handle received data\n");
 	} else {
-		pr_err("rf mode unknown\n");
-		kfree_skb(skb);
+		nci_data_exchange_complete(ndev, skb, conn_id, err);
 	}
 }
 
@@ -247,6 +267,8 @@ void nci_rx_data_packet(struct nci_dev *ndev, struct sk_buff *skb)
 {
 	__u8 pbf = nci_pbf(skb->data);
 	__u8 status = 0;
+	__u8 conn_id = nci_conn_id(skb->data);
+	struct nci_conn_info    *conn_info;
 
 	pr_debug("len %d\n", skb->len);
 
@@ -255,6 +277,10 @@ void nci_rx_data_packet(struct nci_dev *ndev, struct sk_buff *skb)
 		 nci_conn_id(skb->data),
 		 nci_plen(skb->data));
 
+	conn_info = nci_get_conn_info_by_conn_id(ndev, nci_conn_id(skb->data));
+	if (!conn_info)
+		return;
+
 	/* strip the nci data header */
 	skb_pull(skb, NCI_DATA_HDR_SIZE);
 
@@ -268,5 +294,5 @@ void nci_rx_data_packet(struct nci_dev *ndev, struct sk_buff *skb)
 		skb_trim(skb, (skb->len - 1));
 	}
 
-	nci_add_rx_data_frag(ndev, skb, pbf, nci_to_errno(status));
+	nci_add_rx_data_frag(ndev, skb, pbf, conn_id, nci_to_errno(status));
 }