NFC: st21nfca: Adding P2P support to st21nfca in Initiator & Target mode

Support for Initiator and Target mode with ISO18092 commands support:
- ATR_REQ/ATR_RES
- PSL_REQ/PSL_RES
- DEP_REQ/DEP_RES

Work based on net/nfc/digital_dep.c.
st21nfca is using:
- Gate reader F for P2P in initiator mode.
- Gate card F for P2P in target mode.

Felica tag and p2p are differentiated with NFCID2.
When starting with 01FE it is acting in p2p mode.

On complete_target_discovered on ST21NFCA_RF_READER_F_GATE
supported_protocols is set to NFC_PROTO_NFC_DEP_MASK
for P2P.

Tested against: Nexus S, Galaxy S2, Galaxy S3, Galaxy S3 Mini,
Nexus 4 & Nexus 5.

Signed-off-by: Christophe Ricard <[e-mail]>
Signed-off-by: Samuel Ortiz <[e-mail]>

drivers/nfc/st21nfca/Makefile

···
 
 st21nfca_i2c-objs  = i2c.o
 
-obj-$(CONFIG_NFC_ST21NFCA)     += st21nfca.o
+obj-$(CONFIG_NFC_ST21NFCA)     += st21nfca.o st21nfca_dep.o
 obj-$(CONFIG_NFC_ST21NFCA_I2C) += st21nfca_i2c.o

drivers/nfc/st21nfca/st21nfca.c

···
 #include <net/nfc/llc.h>
 
 #include "st21nfca.h"
+#include "st21nfca_dep.h"
 
 #define DRIVER_DESC "HCI NFC driver for ST21NFCA"
 
···
 	{ST21NFCA_RF_READER_F_GATE, NFC_HCI_INVALID_PIPE},
 	{ST21NFCA_RF_READER_14443_3_A_GATE, NFC_HCI_INVALID_PIPE},
 	{ST21NFCA_RF_READER_ISO15693_GATE, NFC_HCI_INVALID_PIPE},
+	{ST21NFCA_RF_CARD_F_GATE, NFC_HCI_INVALID_PIPE},
 };
 
 struct st21nfca_pipe_info {
···
 				   u32 im_protocols, u32 tm_protocols)
 {
 	int r;
+	u32 pol_req;
+	u8 param[19];
+	struct sk_buff *datarate_skb;
 
 	pr_info(DRIVER_DESC ": %s protocols 0x%x 0x%x\n",
 		__func__, im_protocols, tm_protocols);
···
 					ST21NFCA_RF_READER_F_GATE);
 			if (r < 0)
 				return r;
+		} else {
+			hdev->gb = nfc_get_local_general_bytes(hdev->ndev,
+							       &hdev->gb_len);
+
+			if (hdev->gb == NULL || hdev->gb_len == 0) {
+				im_protocols &= ~NFC_PROTO_NFC_DEP_MASK;
+				tm_protocols &= ~NFC_PROTO_NFC_DEP_MASK;
+			}
+
+			param[0] = ST21NFCA_RF_READER_F_DATARATE_106 |
+			    ST21NFCA_RF_READER_F_DATARATE_212 |
+			    ST21NFCA_RF_READER_F_DATARATE_424;
+			r = nfc_hci_set_param(hdev, ST21NFCA_RF_READER_F_GATE,
+					      ST21NFCA_RF_READER_F_DATARATE,
+					      param, 1);
+			if (r < 0)
+				return r;
+
+			pol_req =
+			    be32_to_cpu(ST21NFCA_RF_READER_F_POL_REQ_DEFAULT);
+			r = nfc_hci_set_param(hdev, ST21NFCA_RF_READER_F_GATE,
+					      ST21NFCA_RF_READER_F_POL_REQ,
+					      (u8 *) &pol_req, 4);
+			if (r < 0)
+				return r;
 		}
 
 		if ((ST21NFCA_RF_READER_14443_3_A_GATE & im_protocols) == 0) {
···
 			nfc_hci_send_event(hdev, NFC_HCI_RF_READER_A_GATE,
 					   NFC_HCI_EVT_END_OPERATION, NULL, 0);
 	}
+
+	if (tm_protocols & NFC_PROTO_NFC_DEP_MASK) {
+		r = nfc_hci_get_param(hdev, ST21NFCA_RF_CARD_F_GATE,
+				      ST21NFCA_RF_CARD_F_DATARATE,
+				      &datarate_skb);
+		if (r < 0)
+			return r;
+
+		/* Configure the maximum supported datarate to 424Kbps */
+		if (datarate_skb->len > 0 &&
+		    datarate_skb->data[0] !=
+		    ST21NFCA_RF_CARD_F_DATARATE_212_424) {
+			param[0] = ST21NFCA_RF_CARD_F_DATARATE_212_424;
+			r = nfc_hci_set_param(hdev, ST21NFCA_RF_CARD_F_GATE,
+					      ST21NFCA_RF_CARD_F_DATARATE,
+					      param, 1);
+			if (r < 0)
+				return r;
+		}
+
+		/*
+		 * Configure sens_res
+		 *
+		 * NFC Forum Digital Spec Table 7:
+		 * NFCID1 size: triple (10 bytes)
+		 */
+		param[0] = 0x00;
+		param[1] = 0x08;
+		r = nfc_hci_set_param(hdev, ST21NFCA_RF_CARD_F_GATE,
+				      ST21NFCA_RF_CARD_F_SENS_RES, param, 2);
+		if (r < 0)
+			return r;
+
+		/*
+		 * Configure sel_res
+		 *
+		 * NFC Forum Digistal Spec Table 17:
+		 * b3 set to 0b (value b7-b6):
+		 * - 10b: Configured for NFC-DEP Protocol
+		 */
+		param[0] = 0x40;
+		r = nfc_hci_set_param(hdev, ST21NFCA_RF_CARD_F_GATE,
+				      ST21NFCA_RF_CARD_F_SEL_RES, param, 1);
+		if (r < 0)
+			return r;
+
+		/* Configure NFCID1 Random uid */
+		r = nfc_hci_set_param(hdev, ST21NFCA_RF_CARD_F_GATE,
+				      ST21NFCA_RF_CARD_F_NFCID1, NULL, 0);
+		if (r < 0)
+			return r;
+
+		/* Configure NFCID2_LIST */
+		/* System Code */
+		param[0] = 0x00;
+		param[1] = 0x00;
+		/* NFCID2 */
+		param[2] = 0x01;
+		param[3] = 0xfe;
+		param[4] = 'S';
+		param[5] = 'T';
+		param[6] = 'M';
+		param[7] = 'i';
+		param[8] = 'c';
+		param[9] = 'r';
+		/* 8 byte Pad bytes used for polling respone frame */
+
+		/*
+		 * Configuration byte:
+		 * - bit 0: define the default NFCID2 entry used when the
+		 * system code is equal to 'FFFF'
+		 * - bit 1: use a random value for lowest 6 bytes of
+		 * NFCID2 value
+		 * - bit 2: ignore polling request frame if request code
+		 * is equal to '01'
+		 * - Other bits are RFU
+		 */
+		param[18] = 0x01;
+		r = nfc_hci_set_param(hdev, ST21NFCA_RF_CARD_F_GATE,
+				      ST21NFCA_RF_CARD_F_NFCID2_LIST, param,
+				      19);
+		if (r < 0)
+			return r;
+
+		param[0] = 0x02;
+		r = nfc_hci_set_param(hdev, ST21NFCA_RF_CARD_F_GATE,
+				      ST21NFCA_RF_CARD_F_MODE, param, 1);
+	}
+
 	return r;
 }
 
···
 	return r;
 }
 
+static int st21nfca_hci_dep_link_up(struct nfc_hci_dev *hdev,
+				    struct nfc_target *target, u8 comm_mode,
+				    u8 *gb, size_t gb_len)
+{
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+
+	info->dep_info.idx = target->idx;
+	return st21nfca_im_send_atr_req(hdev, gb, gb_len);
+}
+
+static int st21nfca_hci_dep_link_down(struct nfc_hci_dev *hdev)
+{
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+
+	info->state = ST21NFCA_ST_READY;
+
+	return nfc_hci_send_cmd(hdev, ST21NFCA_DEVICE_MGNT_GATE,
+				ST21NFCA_DM_DISCONNECT, NULL, 0, NULL);
+}
+
 static int st21nfca_hci_target_from_gate(struct nfc_hci_dev *hdev, u8 gate,
 					 struct nfc_target *target)
 {
···
 	return 0;
 }
 
+static int st21nfca_hci_complete_target_discovered(struct nfc_hci_dev *hdev,
+						u8 gate,
+						struct nfc_target *target)
+{
+	int r;
+	struct sk_buff *nfcid2_skb = NULL, *nfcid1_skb;
+
+	if (gate == ST21NFCA_RF_READER_F_GATE) {
+		r = nfc_hci_get_param(hdev, ST21NFCA_RF_READER_F_GATE,
+				ST21NFCA_RF_READER_F_NFCID2, &nfcid2_skb);
+		if (r < 0)
+			goto exit;
+
+		if (nfcid2_skb->len > NFC_SENSF_RES_MAXSIZE) {
+			r = -EPROTO;
+			goto exit;
+		}
+
+		/*
+		 * - After the recepton of polling response for type F frame
+		 * at 212 or 424 Kbit/s, NFCID2 registry parameters will be
+		 * updated.
+		 * - After the reception of SEL_RES with NFCIP-1 compliant bit
+		 * set for type A frame NFCID1 will be updated
+		 */
+		if (nfcid2_skb->len > 0) {
+			/* P2P in type F */
+			memcpy(target->sensf_res, nfcid2_skb->data,
+				nfcid2_skb->len);
+			target->sensf_res_len = nfcid2_skb->len;
+			/* NFC Forum Digital Protocol Table 44 */
+			if (target->sensf_res[0] == 0x01 &&
+			    target->sensf_res[1] == 0xfe)
+				target->supported_protocols =
+							NFC_PROTO_NFC_DEP_MASK;
+			else
+				target->supported_protocols =
+							NFC_PROTO_FELICA_MASK;
+		} else {
+			/* P2P in type A */
+			r = nfc_hci_get_param(hdev, ST21NFCA_RF_READER_F_GATE,
+					ST21NFCA_RF_READER_F_NFCID1,
+					&nfcid1_skb);
+			if (r < 0)
+				goto exit;
+
+			if (nfcid1_skb->len > NFC_NFCID1_MAXSIZE) {
+				r = -EPROTO;
+				goto exit;
+			}
+			memcpy(target->sensf_res, nfcid1_skb->data,
+				nfcid1_skb->len);
+			target->sensf_res_len = nfcid1_skb->len;
+			target->supported_protocols = NFC_PROTO_NFC_DEP_MASK;
+		}
+		target->hci_reader_gate = ST21NFCA_RF_READER_F_GATE;
+	}
+	r = 1;
+exit:
+	kfree_skb(nfcid2_skb);
+	return r;
+}
+
 #define ST21NFCA_CB_TYPE_READER_ISO15693 1
 static void st21nfca_hci_data_exchange_cb(void *context, struct sk_buff *skb,
 					  int err)
···
 
 	switch (target->hci_reader_gate) {
 	case ST21NFCA_RF_READER_F_GATE:
+		if (target->supported_protocols == NFC_PROTO_NFC_DEP_MASK)
+			return st21nfca_im_send_dep_req(hdev, skb);
+
 		*skb_push(skb, 1) = 0x1a;
 		return nfc_hci_send_cmd_async(hdev, target->hci_reader_gate,
 					      ST21NFCA_WR_XCHG_DATA, skb->data,
···
 	}
 }
 
+static int st21nfca_hci_tm_send(struct nfc_hci_dev *hdev, struct sk_buff *skb)
+{
+	return st21nfca_tm_send_dep_res(hdev, skb);
+}
+
 static int st21nfca_hci_check_presence(struct nfc_hci_dev *hdev,
 				       struct nfc_target *target)
 {
···
 	}
 }
 
+/*
+ * Returns:
+ * <= 0: driver handled the event, skb consumed
+ *    1: driver does not handle the event, please do standard processing
+ */
+static int st21nfca_hci_event_received(struct nfc_hci_dev *hdev, u8 gate,
+				       u8 event, struct sk_buff *skb)
+{
+	int r;
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+
+	pr_debug("hci event: %d\n", event);
+
+	switch (event) {
+	case ST21NFCA_EVT_CARD_ACTIVATED:
+		if (gate == ST21NFCA_RF_CARD_F_GATE)
+			info->dep_info.curr_nfc_dep_pni = 0;
+		break;
+	case ST21NFCA_EVT_CARD_DEACTIVATED:
+		break;
+	case ST21NFCA_EVT_FIELD_ON:
+		break;
+	case ST21NFCA_EVT_FIELD_OFF:
+		break;
+	case ST21NFCA_EVT_SEND_DATA:
+		if (gate == ST21NFCA_RF_CARD_F_GATE) {
+			r = st21nfca_tm_event_send_data(hdev, skb, gate);
+			if (r < 0)
+				goto exit;
+			return 0;
+		} else {
+			info->dep_info.curr_nfc_dep_pni = 0;
+			return 1;
+		}
+		break;
+	default:
+		return 1;
+	}
+	kfree_skb(skb);
+	return 0;
+exit:
+	return r;
+}
+
 static struct nfc_hci_ops st21nfca_hci_ops = {
 	.open = st21nfca_hci_open,
 	.close = st21nfca_hci_close,
···
 	.xmit = st21nfca_hci_xmit,
 	.start_poll = st21nfca_hci_start_poll,
 	.stop_poll = st21nfca_hci_stop_poll,
+	.dep_link_up = st21nfca_hci_dep_link_up,
+	.dep_link_down = st21nfca_hci_dep_link_down,
 	.target_from_gate = st21nfca_hci_target_from_gate,
+	.complete_target_discovered = st21nfca_hci_complete_target_discovered,
 	.im_transceive = st21nfca_hci_im_transceive,
+	.tm_send = st21nfca_hci_tm_send,
 	.check_presence = st21nfca_hci_check_presence,
+	.event_received = st21nfca_hci_event_received,
 };
 
 int st21nfca_hci_probe(void *phy_id, struct nfc_phy_ops *phy_ops,
···
 	    NFC_PROTO_FELICA_MASK |
 	    NFC_PROTO_ISO14443_MASK |
 	    NFC_PROTO_ISO14443_B_MASK |
-	    NFC_PROTO_ISO15693_MASK;
+	    NFC_PROTO_ISO15693_MASK |
+	    NFC_PROTO_NFC_DEP_MASK;
 
 	set_bit(NFC_HCI_QUIRK_SHORT_CLEAR, &quirks);
 
···
 		goto err_regdev;
 
 	*hdev = info->hdev;
+	st21nfca_dep_init(info->hdev);
 
 	return 0;
 
···
 {
 	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
 
+	st21nfca_dep_deinit(hdev);
 	nfc_hci_unregister_device(hdev);
 	nfc_hci_free_device(hdev);
 	kfree(info);

drivers/nfc/st21nfca/st21nfca.h

···
 
 #include <net/nfc/hci.h>
 
+#include "st21nfca_dep.h"
+
 #define HCI_MODE 0
 
 /* framing in HCI mode */
···
 	data_exchange_cb_t async_cb;
 	void *async_cb_context;
 
-} __packed;
+	struct st21nfca_dep_info dep_info;
+};
 
 /* Reader RF commands */
 #define ST21NFCA_WR_XCHG_DATA            0x10
···
 #define ST21NFCA_RF_READER_F_DATARATE_106 0x01
 #define ST21NFCA_RF_READER_F_DATARATE_212 0x02
 #define ST21NFCA_RF_READER_F_DATARATE_424 0x04
+#define ST21NFCA_RF_READER_F_POL_REQ    0x02
+#define ST21NFCA_RF_READER_F_POL_REQ_DEFAULT    0xffff0000
+#define ST21NFCA_RF_READER_F_NFCID2 0x03
+#define ST21NFCA_RF_READER_F_NFCID1 0x04
+#define ST21NFCA_RF_READER_F_SENS_RES 0x05
+
+#define ST21NFCA_RF_CARD_F_GATE 0x24
+#define ST21NFCA_RF_CARD_F_MODE 0x01
+#define ST21NFCA_RF_CARD_F_NFCID2_LIST 0x04
+#define ST21NFCA_RF_CARD_F_NFCID1 0x05
+#define ST21NFCA_RF_CARD_F_SENS_RES 0x06
+#define ST21NFCA_RF_CARD_F_SEL_RES 0x07
+#define ST21NFCA_RF_CARD_F_DATARATE 0x08
+#define ST21NFCA_RF_CARD_F_DATARATE_106 0x00
+#define ST21NFCA_RF_CARD_F_DATARATE_212_424 0x01
+
+#define ST21NFCA_EVT_SEND_DATA 0x10
+#define ST21NFCA_EVT_FIELD_ON 0x11
+#define ST21NFCA_EVT_CARD_DEACTIVATED 0x12
+#define ST21NFCA_EVT_CARD_ACTIVATED 0x13
+#define ST21NFCA_EVT_FIELD_OFF 0x14
 
 #endif /* __LOCAL_ST21NFCA_H_ */

drivers/nfc/st21nfca/st21nfca_dep.c

···
+/*
+ * Copyright (C) 2014  STMicroelectronics SAS. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <net/nfc/hci.h>
+
+#include "st21nfca.h"
+#include "st21nfca_dep.h"
+
+#define ST21NFCA_NFCIP1_INITIATOR 0x00
+#define ST21NFCA_NFCIP1_REQ 0xd4
+#define ST21NFCA_NFCIP1_RES 0xd5
+#define ST21NFCA_NFCIP1_ATR_REQ 0x00
+#define ST21NFCA_NFCIP1_ATR_RES 0x01
+#define ST21NFCA_NFCIP1_PSL_REQ 0x04
+#define ST21NFCA_NFCIP1_PSL_RES 0x05
+#define ST21NFCA_NFCIP1_DEP_REQ 0x06
+#define ST21NFCA_NFCIP1_DEP_RES 0x07
+
+#define ST21NFCA_NFC_DEP_PFB_PNI(pfb)     ((pfb) & 0x03)
+#define ST21NFCA_NFC_DEP_PFB_TYPE(pfb) ((pfb) & 0xE0)
+#define ST21NFCA_NFC_DEP_PFB_IS_TIMEOUT(pfb) \
+				((pfb) & ST21NFCA_NFC_DEP_PFB_TIMEOUT_BIT)
+#define ST21NFCA_NFC_DEP_DID_BIT_SET(pfb) ((pfb) & 0x04)
+#define ST21NFCA_NFC_DEP_NAD_BIT_SET(pfb) ((pfb) & 0x08)
+#define ST21NFCA_NFC_DEP_PFB_TIMEOUT_BIT 0x10
+
+#define ST21NFCA_NFC_DEP_PFB_IS_TIMEOUT(pfb) \
+				((pfb) & ST21NFCA_NFC_DEP_PFB_TIMEOUT_BIT)
+
+#define ST21NFCA_NFC_DEP_PFB_I_PDU          0x00
+#define ST21NFCA_NFC_DEP_PFB_ACK_NACK_PDU   0x40
+#define ST21NFCA_NFC_DEP_PFB_SUPERVISOR_PDU 0x80
+
+#define ST21NFCA_ATR_REQ_MIN_SIZE 17
+#define ST21NFCA_ATR_REQ_MAX_SIZE 65
+#define ST21NFCA_LR_BITS_PAYLOAD_SIZE_254B 0x30
+#define ST21NFCA_GB_BIT  0x02
+
+#define ST21NFCA_EVT_CARD_F_BITRATE 0x16
+#define ST21NFCA_EVT_READER_F_BITRATE 0x13
+#define	ST21NFCA_PSL_REQ_SEND_SPEED(brs) (brs & 0x38)
+#define ST21NFCA_PSL_REQ_RECV_SPEED(brs) (brs & 0x07)
+#define ST21NFCA_PP2LRI(pp) ((pp & 0x30) >> 4)
+#define ST21NFCA_CARD_BITRATE_212 0x01
+#define ST21NFCA_CARD_BITRATE_424 0x02
+
+#define ST21NFCA_DEFAULT_TIMEOUT 0x0a
+
+
+#define PROTOCOL_ERR(req) pr_err("%d: ST21NFCA Protocol error: %s\n", \
+				 __LINE__, req)
+
+struct st21nfca_atr_req {
+	u8 length;
+	u8 cmd0;
+	u8 cmd1;
+	u8 nfcid3[NFC_NFCID3_MAXSIZE];
+	u8 did;
+	u8 bsi;
+	u8 bri;
+	u8 ppi;
+	u8 gbi[0];
+} __packed;
+
+struct st21nfca_atr_res {
+	u8 length;
+	u8 cmd0;
+	u8 cmd1;
+	u8 nfcid3[NFC_NFCID3_MAXSIZE];
+	u8 did;
+	u8 bsi;
+	u8 bri;
+	u8 to;
+	u8 ppi;
+	u8 gbi[0];
+} __packed;
+
+struct st21nfca_psl_req {
+	u8 length;
+	u8 cmd0;
+	u8 cmd1;
+	u8 did;
+	u8 brs;
+	u8 fsl;
+} __packed;
+
+struct st21nfca_psl_res {
+	u8 length;
+	u8 cmd0;
+	u8 cmd1;
+	u8 did;
+} __packed;
+
+struct st21nfca_dep_req_res {
+	u8 length;
+	u8 cmd0;
+	u8 cmd1;
+	u8 pfb;
+	u8 did;
+	u8 nad;
+} __packed;
+
+static void st21nfca_tx_work(struct work_struct *work)
+{
+	struct st21nfca_hci_info *info = container_of(work,
+						struct st21nfca_hci_info,
+						dep_info.tx_work);
+
+	struct nfc_dev *dev;
+	struct sk_buff *skb;
+	if (info) {
+		dev = info->hdev->ndev;
+		skb = info->dep_info.tx_pending;
+
+		device_lock(&dev->dev);
+
+		nfc_hci_send_cmd_async(info->hdev, ST21NFCA_RF_READER_F_GATE,
+							ST21NFCA_WR_XCHG_DATA,
+							skb->data, skb->len,
+							info->async_cb, info);
+		device_unlock(&dev->dev);
+		kfree_skb(skb);
+	}
+}
+
+static void st21nfca_im_send_pdu(struct st21nfca_hci_info *info,
+						struct sk_buff *skb)
+{
+	info->dep_info.tx_pending = skb;
+	schedule_work(&info->dep_info.tx_work);
+}
+
+static int st21nfca_tm_send_atr_res(struct nfc_hci_dev *hdev,
+				    struct st21nfca_atr_req *atr_req)
+{
+	struct st21nfca_atr_res *atr_res;
+	struct sk_buff *skb;
+	size_t gb_len;
+	int r;
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+
+	gb_len = atr_req->length - sizeof(struct st21nfca_atr_req);
+	skb = alloc_skb(atr_req->length + 1, GFP_KERNEL);
+	if (!skb)
+		return -ENOMEM;
+
+	skb_put(skb, sizeof(struct st21nfca_atr_res));
+
+	atr_res = (struct st21nfca_atr_res *)skb->data;
+	memset(atr_res, 0, sizeof(struct st21nfca_atr_res));
+
+	atr_res->length = atr_req->length + 1;
+	atr_res->cmd0 = ST21NFCA_NFCIP1_RES;
+	atr_res->cmd1 = ST21NFCA_NFCIP1_ATR_RES;
+
+	memcpy(atr_res->nfcid3, atr_req->nfcid3, 6);
+	atr_res->bsi = 0x00;
+	atr_res->bri = 0x00;
+	atr_res->to = ST21NFCA_DEFAULT_TIMEOUT;
+	atr_res->ppi = ST21NFCA_LR_BITS_PAYLOAD_SIZE_254B;
+
+	if (gb_len) {
+		skb_put(skb, gb_len);
+
+		atr_res->ppi |= ST21NFCA_GB_BIT;
+		memcpy(atr_res->gbi, atr_req->gbi, gb_len);
+		r = nfc_set_remote_general_bytes(hdev->ndev, atr_res->gbi,
+						  gb_len);
+		if (r < 0)
+			return r;
+	}
+
+	info->dep_info.curr_nfc_dep_pni = 0;
+
+	return nfc_hci_send_event(hdev, ST21NFCA_RF_CARD_F_GATE,
+				ST21NFCA_EVT_SEND_DATA, skb->data, skb->len);
+}
+
+static int st21nfca_tm_recv_atr_req(struct nfc_hci_dev *hdev,
+				    struct sk_buff *skb)
+{
+	struct st21nfca_atr_req *atr_req;
+	size_t gb_len;
+	int r;
+
+	skb_trim(skb, skb->len - 1);
+	if (IS_ERR(skb)) {
+		r = PTR_ERR(skb);
+		goto exit;
+	}
+
+	if (!skb->len) {
+		r = -EIO;
+		goto exit;
+	}
+
+	if (skb->len < ST21NFCA_ATR_REQ_MIN_SIZE) {
+		r = -EPROTO;
+		goto exit;
+	}
+
+	atr_req = (struct st21nfca_atr_req *)skb->data;
+
+	r = st21nfca_tm_send_atr_res(hdev, atr_req);
+	if (r)
+		goto exit;
+
+	gb_len = skb->len - sizeof(struct st21nfca_atr_req);
+
+	r = nfc_tm_activated(hdev->ndev, NFC_PROTO_NFC_DEP_MASK,
+			      NFC_COMM_PASSIVE, atr_req->gbi, gb_len);
+	if (r)
+		goto exit;
+
+	r = 0;
+
+exit:
+	return r;
+}
+
+static int st21nfca_tm_send_psl_res(struct nfc_hci_dev *hdev,
+				    struct st21nfca_psl_req *psl_req)
+{
+	struct st21nfca_psl_res *psl_res;
+	struct sk_buff *skb;
+	u8 bitrate[2] = {0, 0};
+
+	int r;
+
+	skb = alloc_skb(sizeof(struct st21nfca_psl_res), GFP_KERNEL);
+	if (!skb)
+		return -ENOMEM;
+	skb_put(skb, sizeof(struct st21nfca_psl_res));
+
+	psl_res = (struct st21nfca_psl_res *)skb->data;
+
+	psl_res->length = sizeof(struct st21nfca_psl_res);
+	psl_res->cmd0 = ST21NFCA_NFCIP1_RES;
+	psl_res->cmd1 = ST21NFCA_NFCIP1_PSL_RES;
+	psl_res->did = psl_req->did;
+
+	r = nfc_hci_send_event(hdev, ST21NFCA_RF_CARD_F_GATE,
+				ST21NFCA_EVT_SEND_DATA, skb->data, skb->len);
+
+	/*
+	 * ST21NFCA only support P2P passive.
+	 * PSL_REQ BRS value != 0 has only a meaning to
+	 * change technology to type F.
+	 * We change to BITRATE 424Kbits.
+	 * In other case switch to BITRATE 106Kbits.
+	 */
+	if (ST21NFCA_PSL_REQ_SEND_SPEED(psl_req->brs) &&
+	    ST21NFCA_PSL_REQ_RECV_SPEED(psl_req->brs)) {
+		bitrate[0] = ST21NFCA_CARD_BITRATE_424;
+		bitrate[1] = ST21NFCA_CARD_BITRATE_424;
+	}
+
+	/* Send an event to change bitrate change event to card f */
+	return nfc_hci_send_event(hdev, ST21NFCA_RF_CARD_F_GATE,
+			ST21NFCA_EVT_CARD_F_BITRATE, bitrate, 2);
+}
+
+static int st21nfca_tm_recv_psl_req(struct nfc_hci_dev *hdev,
+				    struct sk_buff *skb)
+{
+	struct st21nfca_psl_req *psl_req;
+	int r;
+
+	skb_trim(skb, skb->len - 1);
+	if (IS_ERR(skb)) {
+		r = PTR_ERR(skb);
+		skb = NULL;
+		goto exit;
+	}
+
+	if (!skb->len) {
+		r = -EIO;
+		goto exit;
+	}
+
+	psl_req = (struct st21nfca_psl_req *)skb->data;
+
+	if (skb->len < sizeof(struct st21nfca_psl_req)) {
+		r = -EIO;
+		goto exit;
+	}
+
+	r = st21nfca_tm_send_psl_res(hdev, psl_req);
+exit:
+	return r;
+}
+
+int st21nfca_tm_send_dep_res(struct nfc_hci_dev *hdev, struct sk_buff *skb)
+{
+	int r;
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+
+	*skb_push(skb, 1) = info->dep_info.curr_nfc_dep_pni;
+	*skb_push(skb, 1) = ST21NFCA_NFCIP1_DEP_RES;
+	*skb_push(skb, 1) = ST21NFCA_NFCIP1_RES;
+	*skb_push(skb, 1) = skb->len;
+
+	r = nfc_hci_send_event(hdev, ST21NFCA_RF_CARD_F_GATE,
+				ST21NFCA_EVT_SEND_DATA, skb->data, skb->len);
+	kfree_skb(skb);
+
+	return r;
+}
+EXPORT_SYMBOL(st21nfca_tm_send_dep_res);
+
+static int st21nfca_tm_recv_dep_req(struct nfc_hci_dev *hdev,
+				    struct sk_buff *skb)
+{
+	struct st21nfca_dep_req_res *dep_req;
+	u8 size;
+	int r;
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+
+	skb_trim(skb, skb->len - 1);
+	if (IS_ERR(skb)) {
+		r = PTR_ERR(skb);
+		skb = NULL;
+		goto exit;
+	}
+
+	size = 4;
+
+	dep_req = (struct st21nfca_dep_req_res *)skb->data;
+	if (skb->len < size) {
+		r = -EIO;
+		goto exit;
+	}
+
+	if (ST21NFCA_NFC_DEP_DID_BIT_SET(dep_req->pfb))
+		size++;
+	if (ST21NFCA_NFC_DEP_NAD_BIT_SET(dep_req->pfb))
+		size++;
+
+	if (skb->len < size) {
+		r = -EIO;
+		goto exit;
+	}
+
+	/* Receiving DEP_REQ - Decoding */
+	switch (ST21NFCA_NFC_DEP_PFB_TYPE(dep_req->pfb)) {
+	case ST21NFCA_NFC_DEP_PFB_I_PDU:
+		info->dep_info.curr_nfc_dep_pni =
+				ST21NFCA_NFC_DEP_PFB_PNI(dep_req->pfb);
+		break;
+	case ST21NFCA_NFC_DEP_PFB_ACK_NACK_PDU:
+		pr_err("Received a ACK/NACK PDU\n");
+		break;
+	case ST21NFCA_NFC_DEP_PFB_SUPERVISOR_PDU:
+		pr_err("Received a SUPERVISOR PDU\n");
+		break;
+	}
+
+	if (IS_ERR(skb)) {
+		r = PTR_ERR(skb);
+		skb = NULL;
+		goto exit;
+	}
+
+	skb_pull(skb, size);
+
+	return nfc_tm_data_received(hdev->ndev, skb);
+exit:
+	return r;
+}
+
+int st21nfca_tm_event_send_data(struct nfc_hci_dev *hdev, struct sk_buff *skb,
+				u8 gate)
+{
+	u8 cmd0, cmd1;
+	int r;
+
+	cmd0 = skb->data[1];
+	switch (cmd0) {
+	case ST21NFCA_NFCIP1_REQ:
+		cmd1 = skb->data[2];
+		switch (cmd1) {
+		case ST21NFCA_NFCIP1_ATR_REQ:
+			r = st21nfca_tm_recv_atr_req(hdev, skb);
+			break;
+		case ST21NFCA_NFCIP1_PSL_REQ:
+			r = st21nfca_tm_recv_psl_req(hdev, skb);
+			break;
+		case ST21NFCA_NFCIP1_DEP_REQ:
+			r = st21nfca_tm_recv_dep_req(hdev, skb);
+			break;
+		default:
+			return 1;
+		}
+	default:
+		return 1;
+	}
+	return r;
+}
+EXPORT_SYMBOL(st21nfca_tm_event_send_data);
+
+static void st21nfca_im_send_psl_req(struct nfc_hci_dev *hdev, u8 did, u8 bsi,
+				     u8 bri, u8 lri)
+{
+	struct sk_buff *skb;
+	struct st21nfca_psl_req *psl_req;
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+
+	skb =
+	    alloc_skb(sizeof(struct st21nfca_psl_req) + 1, GFP_KERNEL);
+	if (!skb)
+		return;
+	skb_reserve(skb, 1);
+
+	skb_put(skb, sizeof(struct st21nfca_psl_req));
+	psl_req = (struct st21nfca_psl_req *) skb->data;
+
+	psl_req->length = sizeof(struct st21nfca_psl_req);
+	psl_req->cmd0 = ST21NFCA_NFCIP1_REQ;
+	psl_req->cmd1 = ST21NFCA_NFCIP1_PSL_REQ;
+	psl_req->did = did;
+	psl_req->brs = (0x30 & bsi << 4) | (bri & 0x03);
+	psl_req->fsl = lri;
+
+	*skb_push(skb, 1) = info->dep_info.to | 0x10;
+
+	st21nfca_im_send_pdu(info, skb);
+
+	kfree_skb(skb);
+}
+
+#define ST21NFCA_CB_TYPE_READER_F 1
+static void st21nfca_im_recv_atr_res_cb(void *context, struct sk_buff *skb,
+					int err)
+{
+	struct st21nfca_hci_info *info = context;
+	struct st21nfca_atr_res *atr_res;
+	int r;
+
+	if (err != 0)
+		return;
+
+	if (IS_ERR(skb))
+		return;
+
+	switch (info->async_cb_type) {
+	case ST21NFCA_CB_TYPE_READER_F:
+		skb_trim(skb, skb->len - 1);
+		atr_res = (struct st21nfca_atr_res *)skb->data;
+		r = nfc_set_remote_general_bytes(info->hdev->ndev,
+				atr_res->gbi,
+				skb->len - sizeof(struct st21nfca_atr_res));
+		if (r < 0)
+			return;
+
+		if (atr_res->to >= 0x0e)
+			info->dep_info.to = 0x0e;
+		else
+			info->dep_info.to = atr_res->to + 1;
+
+		info->dep_info.to |= 0x10;
+
+		r = nfc_dep_link_is_up(info->hdev->ndev, info->dep_info.idx,
+					NFC_COMM_PASSIVE, NFC_RF_INITIATOR);
+		if (r < 0)
+			return;
+
+		info->dep_info.curr_nfc_dep_pni = 0;
+		if (ST21NFCA_PP2LRI(atr_res->ppi) != info->dep_info.lri)
+			st21nfca_im_send_psl_req(info->hdev, atr_res->did,
+						atr_res->bsi, atr_res->bri,
+						ST21NFCA_PP2LRI(atr_res->ppi));
+		break;
+	default:
+		if (err == 0)
+			kfree_skb(skb);
+		break;
+	}
+}
+
+int st21nfca_im_send_atr_req(struct nfc_hci_dev *hdev, u8 *gb, size_t gb_len)
+{
+	struct sk_buff *skb;
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+	struct st21nfca_atr_req *atr_req;
+	struct nfc_target *target;
+	uint size;
+
+	info->dep_info.to = ST21NFCA_DEFAULT_TIMEOUT;
+	size = ST21NFCA_ATR_REQ_MIN_SIZE + gb_len;
+	if (size > ST21NFCA_ATR_REQ_MAX_SIZE) {
+		PROTOCOL_ERR("14.6.1.1");
+		return -EINVAL;
+	}
+
+	skb =
+	    alloc_skb(sizeof(struct st21nfca_atr_req) + gb_len + 1, GFP_KERNEL);
+	if (!skb)
+		return -ENOMEM;
+
+	skb_reserve(skb, 1);
+
+	skb_put(skb, sizeof(struct st21nfca_atr_req));
+
+	atr_req = (struct st21nfca_atr_req *)skb->data;
+	memset(atr_req, 0, sizeof(struct st21nfca_atr_req));
+
+	atr_req->cmd0 = ST21NFCA_NFCIP1_REQ;
+	atr_req->cmd1 = ST21NFCA_NFCIP1_ATR_REQ;
+	memset(atr_req->nfcid3, 0, NFC_NFCID3_MAXSIZE);
+	target = hdev->ndev->targets;
+
+	if (target->sensf_res)
+		memcpy(atr_req->nfcid3, target->sensf_res,
+				target->sensf_res_len);
+	else
+		get_random_bytes(atr_req->nfcid3, NFC_NFCID3_MAXSIZE);
+
+	atr_req->did = 0x0;
+
+	atr_req->bsi = 0x00;
+	atr_req->bri = 0x00;
+	atr_req->ppi = ST21NFCA_LR_BITS_PAYLOAD_SIZE_254B;
+	if (gb_len) {
+		atr_req->ppi |= ST21NFCA_GB_BIT;
+		memcpy(skb_put(skb, gb_len), gb, gb_len);
+	}
+	atr_req->length = sizeof(struct st21nfca_atr_req) + hdev->gb_len;
+
+	*skb_push(skb, 1) = info->dep_info.to | 0x10; /* timeout */
+
+	info->async_cb_type = ST21NFCA_CB_TYPE_READER_F;
+	info->async_cb_context = info;
+	info->async_cb = st21nfca_im_recv_atr_res_cb;
+	info->dep_info.bri = atr_req->bri;
+	info->dep_info.bsi = atr_req->bsi;
+	info->dep_info.lri = ST21NFCA_PP2LRI(atr_req->ppi);
+
+	return nfc_hci_send_cmd_async(hdev, ST21NFCA_RF_READER_F_GATE,
+				ST21NFCA_WR_XCHG_DATA, skb->data,
+				skb->len, info->async_cb, info);
+}
+EXPORT_SYMBOL(st21nfca_im_send_atr_req);
+
+static void st21nfca_im_recv_dep_res_cb(void *context, struct sk_buff *skb,
+					int err)
+{
+	struct st21nfca_hci_info *info = context;
+	struct st21nfca_dep_req_res *dep_res;
+
+	int size;
+
+	if (err != 0)
+		return;
+
+	if (IS_ERR(skb))
+		return;
+
+	switch (info->async_cb_type) {
+	case ST21NFCA_CB_TYPE_READER_F:
+		dep_res = (struct st21nfca_dep_req_res *)skb->data;
+
+		size = 3;
+		if (skb->len < size)
+			goto exit;
+
+		if (ST21NFCA_NFC_DEP_DID_BIT_SET(dep_res->pfb))
+			size++;
+		if (ST21NFCA_NFC_DEP_NAD_BIT_SET(dep_res->pfb))
+			size++;
+
+		if (skb->len < size)
+			goto exit;
+
+		skb_trim(skb, skb->len - 1);
+
+		/* Receiving DEP_REQ - Decoding */
+		switch (ST21NFCA_NFC_DEP_PFB_TYPE(dep_res->pfb)) {
+		case ST21NFCA_NFC_DEP_PFB_ACK_NACK_PDU:
+			pr_err("Received a ACK/NACK PDU\n");
+		case ST21NFCA_NFC_DEP_PFB_I_PDU:
+			info->dep_info.curr_nfc_dep_pni =
+			    ST21NFCA_NFC_DEP_PFB_PNI(dep_res->pfb + 1);
+			size++;
+			skb_pull(skb, size);
+			nfc_tm_data_received(info->hdev->ndev, skb);
+			break;
+		case ST21NFCA_NFC_DEP_PFB_SUPERVISOR_PDU:
+			pr_err("Received a SUPERVISOR PDU\n");
+			skb_pull(skb, size);
+			*skb_push(skb, 1) = ST21NFCA_NFCIP1_DEP_REQ;
+			*skb_push(skb, 1) = ST21NFCA_NFCIP1_REQ;
+			*skb_push(skb, 1) = skb->len;
+			*skb_push(skb, 1) = info->dep_info.to | 0x10;
+
+			st21nfca_im_send_pdu(info, skb);
+			break;
+		}
+
+		return;
+	default:
+		break;
+	}
+
+exit:
+	if (err == 0)
+		kfree_skb(skb);
+}
+
+int st21nfca_im_send_dep_req(struct nfc_hci_dev *hdev, struct sk_buff *skb)
+{
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+
+	info->async_cb_type = ST21NFCA_CB_TYPE_READER_F;
+	info->async_cb_context = info;
+	info->async_cb = st21nfca_im_recv_dep_res_cb;
+
+	*skb_push(skb, 1) = info->dep_info.curr_nfc_dep_pni;
+	*skb_push(skb, 1) = ST21NFCA_NFCIP1_DEP_REQ;
+	*skb_push(skb, 1) = ST21NFCA_NFCIP1_REQ;
+	*skb_push(skb, 1) = skb->len;
+
+	*skb_push(skb, 1) = info->dep_info.to | 0x10;
+
+	return nfc_hci_send_cmd_async(hdev, ST21NFCA_RF_READER_F_GATE,
+				      ST21NFCA_WR_XCHG_DATA,
+				      skb->data, skb->len,
+				      info->async_cb, info);
+}
+EXPORT_SYMBOL(st21nfca_im_send_dep_req);
+
+void st21nfca_dep_init(struct nfc_hci_dev *hdev)
+{
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+
+	INIT_WORK(&info->dep_info.tx_work, st21nfca_tx_work);
+	info->dep_info.curr_nfc_dep_pni = 0;
+	info->dep_info.idx = 0;
+	info->dep_info.to = ST21NFCA_DEFAULT_TIMEOUT;
+}
+EXPORT_SYMBOL(st21nfca_dep_init);
+
+void st21nfca_dep_deinit(struct nfc_hci_dev *hdev)
+{
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+
+	cancel_work_sync(&info->dep_info.tx_work);
+}
+EXPORT_SYMBOL(st21nfca_dep_deinit);

drivers/nfc/st21nfca/st21nfca_dep.h

···
+/*
+ * Copyright (C) 2014  STMicroelectronics SAS. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __ST21NFCA_DEP_H
+#define __ST21NFCA_DEP_H
+
+#include <linux/skbuff.h>
+#include <linux/workqueue.h>
+
+struct st21nfca_dep_info {
+	struct sk_buff *tx_pending;
+	struct work_struct tx_work;
+	u8 curr_nfc_dep_pni;
+	u32 idx;
+	u8 to;
+	u8 did;
+	u8 bsi;
+	u8 bri;
+	u8 lri;
+} __packed;
+
+int st21nfca_tm_event_send_data(struct nfc_hci_dev *hdev, struct sk_buff *skb,
+				u8 gate);
+int st21nfca_tm_send_dep_res(struct nfc_hci_dev *hdev, struct sk_buff *skb);
+
+int st21nfca_im_send_atr_req(struct nfc_hci_dev *hdev, u8 *gb, size_t gb_len);
+int st21nfca_im_send_dep_req(struct nfc_hci_dev *hdev, struct sk_buff *skb);
+void st21nfca_dep_init(struct nfc_hci_dev *hdev);
+void st21nfca_dep_deinit(struct nfc_hci_dev *hdev);
+#endif /* __ST21NFCA_DEP_H */