NFC Digital: Add target NFC-DEP support

This adds support for NFC-DEP target mode for NFC-A and NFC-F
technologies.

If the driver provides it, the stack uses an automatic mode for
technology detection and automatic anti-collision. Otherwise the stack
tries to use non-automatic synchronization and listens for SENS_REQ and
SENSF_REQ commands.

The detection, activation, and data exchange procedures work exactly
the same way as in initiator mode, as described in the previous
commits, except that the digital stack waits for commands and sends
responses back to the peer device.

Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 346 insertions, 0 deletions

diff --git a/net/nfc/digital_dep.c b/net/nfc/digital_dep.c
index be984c4..810d00c 100644
--- a/net/nfc/digital_dep.c
+++ b/net/nfc/digital_dep.c
@@ -379,3 +379,349 @@ int digital_in_send_dep_req(struct nfc_digital_dev *ddev,
 	return digital_in_send_cmd(ddev, skb, 1500, digital_in_recv_dep_res,
 				   data_exch);
 }
+
+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;
+	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;
+	}
+
+	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;
+	}
+
+	if (DIGITAL_NFC_DEP_DID_BIT_SET(dep_req->pfb))
+		size++;
+
+	if (resp->len < size) {
+		rc = -EIO;
+		goto exit;
+	}
+
+	switch (DIGITAL_NFC_DEP_PFB_TYPE(dep_req->pfb)) {
+	case DIGITAL_NFC_DEP_PFB_I_PDU:
+		PR_DBG("DIGITAL_NFC_DEP_PFB_I_PDU");
+		ddev->curr_nfc_dep_pni = DIGITAL_NFC_DEP_PFB_PNI(dep_req->pfb);
+		break;
+	case DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU:
+		PR_ERR("Received a ACK/NACK PDU");
+		rc = -EINVAL;
+		goto exit;
+		break;
+	case DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU:
+		PR_ERR("Received a SUPERVISOR PDU");
+		rc = -EINVAL;
+		goto exit;
+		break;
+	}
+
+	skb_pull(resp, size);
+
+	rc = nfc_tm_data_received(ddev->nfc_dev, resp);
+
+exit:
+	if (rc)
+		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;
+
+	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);
+
+	ddev->skb_add_crc(skb);
+
+	return digital_tg_send_cmd(ddev, skb, 1500, digital_tg_recv_dep_req,
+				   NULL);
+}
+
+static void digital_tg_send_psl_res_complete(struct nfc_digital_dev *ddev,
+					     void *arg, struct sk_buff *resp)
+{
+	u8 rf_tech = PTR_ERR(arg);
+
+	if (IS_ERR(resp))
+		return;
+
+	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);
+
+	rc = digital_tg_send_cmd(ddev, skb, 0, digital_tg_send_psl_res_complete,
+				 ERR_PTR(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;
+
+	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("Unsuported dsi value %d", dsi);
+		goto exit;
+	}
+
+	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++;
+
+	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;
+	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 = 8;
+	atr_res->pp = DIGITAL_LR_BITS_PAYLOAD_SIZE_254B;
+	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);
+
+	rc = digital_tg_send_cmd(ddev, skb, 999,
+				 digital_tg_send_atr_res_complete, NULL);
+	if (rc) {
+		kfree_skb(skb);
+		return rc;
+	}
+
+	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;
+
+	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;
+
+		ddev->curr_rf_tech = NFC_DIGITAL_RF_TECH_106A;
+		ddev->skb_add_crc = digital_skb_add_crc_a;
+		ddev->skb_check_crc = digital_skb_check_crc_a;
+	} else {
+		min_size = DIGITAL_ATR_REQ_MIN_SIZE + 1;
+
+		ddev->curr_rf_tech = NFC_DIGITAL_RF_TECH_212F;
+		ddev->skb_add_crc = digital_skb_add_crc_f;
+		ddev->skb_check_crc = digital_skb_check_crc_f;
+	}
+
+	if (resp->len < min_size) {
+		rc = -EIO;
+		goto exit;
+	}
+
+	if (DIGITAL_DRV_CAPS_TG_CRC(ddev)) {
+		ddev->skb_add_crc = digital_skb_add_crc_none;
+		ddev->skb_check_crc = digital_skb_check_crc_none;
+	}
+
+	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) {
+		rc = -EINVAL;
+		goto exit;
+	}
+
+	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);
+	rc = nfc_tm_activated(ddev->nfc_dev, NFC_PROTO_NFC_DEP_MASK,
+			      NFC_COMM_PASSIVE, atr_req->gb, gb_len);
+	if (rc)
+		goto exit;
+
+	ddev->poll_tech_count = 0;
+
+	rc = 0;
+exit:
+	if (rc)
+		digital_poll_next_tech(ddev);
+
+	dev_kfree_skb(resp);
+}