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, 296 insertions, 0 deletions

diff --git a/net/nfc/digital_technology.c b/net/nfc/digital_technology.c
index 0c28f60..564735f 100644
--- a/net/nfc/digital_technology.c
+++ b/net/nfc/digital_technology.c
@@ -475,3 +475,299 @@ int digital_in_send_sensf_req(struct nfc_digital_dev *ddev, u8 rf_tech)
 
 	return rc;
 }
+
+static int digital_tg_send_sel_res(struct nfc_digital_dev *ddev)
+{
+	struct sk_buff *skb;
+	int rc;
+
+	skb = digital_skb_alloc(ddev, 1);
+	if (!skb)
+		return -ENOMEM;
+
+	*skb_put(skb, 1) = DIGITAL_SEL_RES_NFC_DEP;
+
+	if (!DIGITAL_DRV_CAPS_TG_CRC(ddev))
+		digital_skb_add_crc_a(skb);
+
+	rc = digital_tg_send_cmd(ddev, skb, 300, digital_tg_recv_atr_req,
+				 NULL);
+	if (rc)
+		kfree_skb(skb);
+
+	return rc;
+}
+
+static void digital_tg_recv_sel_req(struct nfc_digital_dev *ddev, void *arg,
+				    struct sk_buff *resp)
+{
+	int rc;
+
+	if (IS_ERR(resp)) {
+		rc = PTR_ERR(resp);
+		resp = NULL;
+		goto exit;
+	}
+
+	if (!DIGITAL_DRV_CAPS_TG_CRC(ddev)) {
+		rc = digital_skb_check_crc_a(resp);
+		if (rc) {
+			PROTOCOL_ERR("4.4.1.3");
+			goto exit;
+		}
+	}
+
+	/* Silently ignore SEL_REQ content and send a SEL_RES for NFC-DEP */
+
+	rc = digital_tg_send_sel_res(ddev);
+
+exit:
+	if (rc)
+		digital_poll_next_tech(ddev);
+
+	dev_kfree_skb(resp);
+}
+
+static int digital_tg_send_sdd_res(struct nfc_digital_dev *ddev)
+{
+	struct sk_buff *skb;
+	struct digital_sdd_res *sdd_res;
+	int rc, i;
+
+	skb = digital_skb_alloc(ddev, sizeof(struct digital_sdd_res));
+	if (!skb)
+		return -ENOMEM;
+
+	skb_put(skb, sizeof(struct digital_sdd_res));
+	sdd_res = (struct digital_sdd_res *)skb->data;
+
+	sdd_res->nfcid1[0] = 0x08;
+	get_random_bytes(sdd_res->nfcid1 + 1, 3);
+
+	sdd_res->bcc = 0;
+	for (i = 0; i < 4; i++)
+		sdd_res->bcc ^= sdd_res->nfcid1[i];
+
+	rc = digital_tg_send_cmd(ddev, skb, 300, digital_tg_recv_sel_req,
+				 NULL);
+	if (rc)
+		kfree_skb(skb);
+
+	return rc;
+}
+
+static void digital_tg_recv_sdd_req(struct nfc_digital_dev *ddev, void *arg,
+				    struct sk_buff *resp)
+{
+	u8 *sdd_req;
+	int rc;
+
+	if (IS_ERR(resp)) {
+		rc = PTR_ERR(resp);
+		resp = NULL;
+		goto exit;
+	}
+
+	sdd_req = resp->data;
+
+	if (resp->len < 2 || sdd_req[0] != DIGITAL_CMD_SEL_REQ_CL1 ||
+	    sdd_req[1] != DIGITAL_SDD_REQ_SEL_PAR) {
+		rc = -EINVAL;
+		goto exit;
+	}
+
+	rc = digital_tg_send_sdd_res(ddev);
+
+exit:
+	if (rc)
+		digital_poll_next_tech(ddev);
+
+	dev_kfree_skb(resp);
+}
+
+static int digital_tg_send_sens_res(struct nfc_digital_dev *ddev)
+{
+	struct sk_buff *skb;
+	u8 *sens_res;
+	int rc;
+
+	skb = digital_skb_alloc(ddev, 2);
+	if (!skb)
+		return -ENOMEM;
+
+	sens_res = skb_put(skb, 2);
+
+	sens_res[0] = (DIGITAL_SENS_RES_NFC_DEP >> 8) & 0xFF;
+	sens_res[1] = DIGITAL_SENS_RES_NFC_DEP & 0xFF;
+
+	rc = digital_tg_send_cmd(ddev, skb, 300, digital_tg_recv_sdd_req,
+				 NULL);
+	if (rc)
+		kfree_skb(skb);
+
+	return rc;
+}
+
+void digital_tg_recv_sens_req(struct nfc_digital_dev *ddev, void *arg,
+			      struct sk_buff *resp)
+{
+	u8 sens_req;
+	int rc;
+
+	if (IS_ERR(resp)) {
+		rc = PTR_ERR(resp);
+		resp = NULL;
+		goto exit;
+	}
+
+	sens_req = resp->data[0];
+
+	if (!resp->len || (sens_req != DIGITAL_CMD_SENS_REQ &&
+	    sens_req != DIGITAL_CMD_ALL_REQ)) {
+		rc = -EINVAL;
+		goto exit;
+	}
+
+	rc = digital_tg_send_sens_res(ddev);
+
+exit:
+	if (rc)
+		digital_poll_next_tech(ddev);
+
+	dev_kfree_skb(resp);
+}
+
+int digital_tg_send_sensf_res(struct nfc_digital_dev *ddev,
+			      struct digital_sensf_req *sensf_req)
+{
+	struct sk_buff *skb;
+	u8 size;
+	int rc;
+	struct digital_sensf_res *sensf_res;
+
+	size = sizeof(struct digital_sensf_res);
+
+	if (sensf_req->rc != DIGITAL_SENSF_REQ_RC_NONE)
+		size -= sizeof(sensf_res->rd);
+
+	skb = digital_skb_alloc(ddev, size);
+	if (!skb)
+		return -ENOMEM;
+
+	skb_put(skb, size);
+
+	sensf_res = (struct digital_sensf_res *)skb->data;
+
+	memset(sensf_res, 0, size);
+
+	sensf_res->cmd = DIGITAL_CMD_SENSF_RES;
+	sensf_res->nfcid2[0] = DIGITAL_SENSF_NFCID2_NFC_DEP_B1;
+	sensf_res->nfcid2[1] = DIGITAL_SENSF_NFCID2_NFC_DEP_B2;
+	get_random_bytes(&sensf_res->nfcid2[2], 6);
+
+	switch (sensf_req->rc) {
+	case DIGITAL_SENSF_REQ_RC_SC:
+		sensf_res->rd[0] = sensf_req->sc1;
+		sensf_res->rd[1] = sensf_req->sc2;
+		break;
+	case DIGITAL_SENSF_REQ_RC_AP:
+		sensf_res->rd[0] = DIGITAL_SENSF_RES_RD_AP_B1;
+		sensf_res->rd[1] = DIGITAL_SENSF_RES_RD_AP_B2;
+		break;
+	}
+
+	*skb_push(skb, sizeof(u8)) = size + 1;
+
+	if (!DIGITAL_DRV_CAPS_TG_CRC(ddev))
+		digital_skb_add_crc_f(skb);
+
+	rc = digital_tg_send_cmd(ddev, skb, 300,
+				 digital_tg_recv_atr_req, NULL);
+	if (rc)
+		kfree_skb(skb);
+
+	return rc;
+}
+
+void digital_tg_recv_sensf_req(struct nfc_digital_dev *ddev, void *arg,
+			       struct sk_buff *resp)
+{
+	struct digital_sensf_req *sensf_req;
+	int rc;
+
+	if (IS_ERR(resp)) {
+		rc = PTR_ERR(resp);
+		resp = NULL;
+		goto exit;
+	}
+
+	if (!DIGITAL_DRV_CAPS_TG_CRC(ddev)) {
+		rc = digital_skb_check_crc_f(resp);
+		if (rc) {
+			PROTOCOL_ERR("6.4.1.8");
+			goto exit;
+		}
+	}
+
+	if (resp->len != sizeof(struct digital_sensf_req) + 1) {
+		rc = -EINVAL;
+		goto exit;
+	}
+
+	skb_pull(resp, 1);
+	sensf_req = (struct digital_sensf_req *)resp->data;
+
+	if (sensf_req->cmd != DIGITAL_CMD_SENSF_REQ) {
+		rc = -EINVAL;
+		goto exit;
+	}
+
+	rc = digital_tg_send_sensf_res(ddev, sensf_req);
+
+exit:
+	if (rc)
+		digital_poll_next_tech(ddev);
+
+	dev_kfree_skb(resp);
+}
+
+int digital_tg_listen_nfca(struct nfc_digital_dev *ddev, u8 rf_tech)
+{
+	int rc;
+
+	rc = digital_tg_configure_hw(ddev, NFC_DIGITAL_CONFIG_RF_TECH, rf_tech);
+	if (rc)
+		return rc;
+
+	rc = digital_tg_configure_hw(ddev, NFC_DIGITAL_CONFIG_FRAMING,
+				     NFC_DIGITAL_FRAMING_NFCA_NFC_DEP);
+	if (rc)
+		return rc;
+
+	return digital_tg_listen(ddev, 300, digital_tg_recv_sens_req, NULL);
+}
+
+int digital_tg_listen_nfcf(struct nfc_digital_dev *ddev, u8 rf_tech)
+{
+	int rc;
+	u8 *nfcid2;
+
+	rc = digital_tg_configure_hw(ddev, NFC_DIGITAL_CONFIG_RF_TECH, rf_tech);
+	if (rc)
+		return rc;
+
+	rc = digital_tg_configure_hw(ddev, NFC_DIGITAL_CONFIG_FRAMING,
+				     NFC_DIGITAL_FRAMING_NFCF_NFC_DEP);
+	if (rc)
+		return rc;
+
+	nfcid2 = kzalloc(NFC_NFCID2_MAXSIZE, GFP_KERNEL);
+	if (!nfcid2)
+		return -ENOMEM;
+
+	nfcid2[0] = DIGITAL_SENSF_NFCID2_NFC_DEP_B1;
+	nfcid2[1] = DIGITAL_SENSF_NFCID2_NFC_DEP_B2;
+	get_random_bytes(nfcid2 + 2, NFC_NFCID2_MAXSIZE - 2);
+
+	return digital_tg_listen(ddev, 300, digital_tg_recv_sensf_req, nfcid2);
+}