NFC: Implement NCI dep_link_up and dep_link_down

During NFC-DEP target activation, store the remote
general bytes to be used later in dep_link_up.
When dep_link_up is called, activate the NFC-DEP target,
and forward the remote general bytes.
When dep_link_down is called, deactivate the target.

Signed-off-by: Ilan Elias <ilane@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

include/net/nfc/nci_core.h

@@ -138,6 +138,10 @@ struct nci_dev {
 	data_exchange_cb_t	data_exchange_cb;
 	void			*data_exchange_cb_context;
 	struct sk_buff		*rx_data_reassembly;
+
+	/* stored during intf_activated_ntf */
+	__u8 remote_gb[NFC_MAX_GT_LEN];
+	__u8 remote_gb_len;
 };
 
 /* ----- NCI Devices ----- */

include/net/nfc/nfc.h

@@ -72,6 +72,7 @@ struct nfc_ops {
 
 #define NFC_TARGET_IDX_ANY -1
 #define NFC_MAX_GT_LEN 48
+#define NFC_ATR_RES_GT_OFFSET 15
 
 struct nfc_target {
 	u32 idx;

net/nfc/nci/core.c

@@ -564,7 +564,7 @@ static void nci_deactivate_target(struct nfc_dev *nfc_dev,
 {
 	struct nci_dev *ndev = nfc_get_drvdata(nfc_dev);
 
-	pr_debug("target_idx %d\n", target->idx);
+	pr_debug("entry\n");
 
 	if (!ndev->target_active_prot) {
 		pr_err("unable to deactivate target, no active target\n");
@@ -579,6 +579,38 @@ static void nci_deactivate_target(struct nfc_dev *nfc_dev,
 	}
 }
 
+
+static int nci_dep_link_up(struct nfc_dev *nfc_dev, struct nfc_target *target,
+			   __u8 comm_mode, __u8 *gb, size_t gb_len)
+{
+	struct nci_dev *ndev = nfc_get_drvdata(nfc_dev);
+	int rc;
+
+	pr_debug("target_idx %d, comm_mode %d\n", target->idx, comm_mode);
+
+	rc = nci_activate_target(nfc_dev, target, NFC_PROTO_NFC_DEP);
+	if (rc)
+		return rc;
+
+	rc = nfc_set_remote_general_bytes(nfc_dev, ndev->remote_gb,
+					  ndev->remote_gb_len);
+	if (!rc)
+		rc = nfc_dep_link_is_up(nfc_dev, target->idx, NFC_COMM_PASSIVE,
+					NFC_RF_INITIATOR);
+
+	return rc;
+}
+
+static int nci_dep_link_down(struct nfc_dev *nfc_dev)
+{
+	pr_debug("entry\n");
+
+	nci_deactivate_target(nfc_dev, NULL);
+
+	return 0;
+}
+
+
 static int nci_transceive(struct nfc_dev *nfc_dev, struct nfc_target *target,
 			  struct sk_buff *skb,
 			  data_exchange_cb_t cb, void *cb_context)
@@ -612,6 +644,8 @@ static struct nfc_ops nci_nfc_ops = {
 	.dev_down = nci_dev_down,
 	.start_poll = nci_start_poll,
 	.stop_poll = nci_stop_poll,
+	.dep_link_up = nci_dep_link_up,
+	.dep_link_down = nci_dep_link_down,
 	.activate_target = nci_activate_target,
 	.deactivate_target = nci_deactivate_target,
 	.im_transceive = nci_transceive,

net/nfc/nci/ntf.c

@@ -176,6 +176,8 @@ static int nci_add_new_protocol(struct nci_dev *ndev,
 			protocol = NFC_PROTO_ISO14443_B_MASK;
 	else if (rf_protocol == NCI_RF_PROTOCOL_T3T)
 		protocol = NFC_PROTO_FELICA_MASK;
+	else if (rf_protocol == NCI_RF_PROTOCOL_NFC_DEP)
+		protocol = NFC_PROTO_NFC_DEP_MASK;
 	else
 		protocol = 0;
 
@@ -505,6 +507,24 @@ exit:
 
 		/* set the available credits to initial value */
 		atomic_set(&ndev->credits_cnt, ndev->initial_num_credits);
+
+		/* store general bytes to be reported later in dep_link_up */
+		if (ntf.rf_interface == NCI_RF_INTERFACE_NFC_DEP) {
+			ndev->remote_gb_len = 0;
+
+			if (ntf.activation_params_len > 0) {
+				/* ATR_RES general bytes at offset 15 */
+				ndev->remote_gb_len = min_t(__u8,
+					(ntf.activation_params
+					.poll_nfc_dep.atr_res_len
+					- NFC_ATR_RES_GT_OFFSET),
+					NFC_MAX_GT_LEN);
+				memcpy(ndev->remote_gb,
+				       (ntf.activation_params.poll_nfc_dep
+				       .atr_res + NFC_ATR_RES_GT_OFFSET),
+				       ndev->remote_gb_len);
+			}
+		}
 	}
 
 	if (atomic_read(&ndev->state) == NCI_DISCOVERY) {