NFC Digital: Add initiator NFC-DEP support

This adds support for NFC-DEP protocol in initiator mode for NFC-A and
NFC-F technologies.

When a target is detected, the process flow is as follow:

For NFC-A technology:
1 - The digital stack receives a SEL_RES as the reply of the SEL_REQ
    command.
2   - If b7 of SEL_RES is set, the peer device is configure for NFC-DEP
      protocol. NFC core is notified through nfc_targets_found().
      Execution continues at step 4.
3   - Otherwise, it's a tag and the NFC core is notified. Detection
      ends.
4 - The digital stacks sends an ATR_REQ command containing a randomly
    generated NFCID3 and the general bytes obtained from the LLCP layer
    of NFC core.

For NFC-F technology:
1 - The digital stack receives a SENSF_RES as the reply of the
    SENSF_REQ command.
2   - If B1 and B2 of NFCID2 are 0x01 and 0xFE respectively, the peer
      device is configured for NFC-DEP protocol. NFC core is notified
      through nfc_targets_found(). Execution continues at step 4.
3   - Otherwise it's a type 3 tag. NFC core is notified. Detection
      ends.
4 - The digital stacks sends an ATR_REQ command containing the NFC-F
    NFCID2 as NFCID3 and the general bytes obtained from the LLCP layer
    of NFC core.

For both technologies:
5 - The digital stacks receives the ATR_RES response containing the
    NFCID3 and the general bytes of the peer device.
6 - The digital stack notifies NFC core that the DEP link is up through
    nfc_dep_link_up().
7 - The NFC core performs data exchange through tm_transceive().
8 - The digital stack sends a DEP_REQ command containing an I PDU with
    the data from NFC core.
9 - The digital stack receives a DEP_RES command
10  - If the DEP_RES response contains a supervisor PDU with timeout
      extension request (RTOX) the digital stack sends a DEP_REQ
      command containing a supervisor PDU acknowledging the RTOX
      request. The execution continues at step 9.
11  - If the DEP_RES response contains an I PDU, the response data is
      passed back to NFC core through the response callback. The
      execution continues at step 8.

Signed-off-by: Thierry Escande <[email protected]>
Signed-off-by: Samuel Ortiz <[email protected]>

net/nfc/Makefile

@@ -10,4 +10,4 @@ obj-$(CONFIG_NFC_DIGITAL) += nfc_digital.o
 nfc-objs := core.o netlink.o af_nfc.o rawsock.o llcp_core.o llcp_commands.o \
 		llcp_sock.o
 
-nfc_digital-objs := digital_core.o digital_technology.o
+nfc_digital-objs := digital_core.o digital_technology.o digital_dep.o

net/nfc/digital.h

@@ -35,6 +35,13 @@
 #define DIGITAL_MAX_HEADER_LEN 7
 #define DIGITAL_CRC_LEN        2
 
+#define DIGITAL_SENSF_NFCID2_NFC_DEP_B1 0x01
+#define DIGITAL_SENSF_NFCID2_NFC_DEP_B2 0xFE
+
+#define DIGITAL_SENS_RES_NFC_DEP 0x0100
+#define DIGITAL_SEL_RES_NFC_DEP  0x40
+#define DIGITAL_SENSF_FELICA_SC  0xFFFF
+
 #define DIGITAL_DRV_CAPS_IN_CRC(ddev) \
 	((ddev)->driver_capabilities & NFC_DIGITAL_DRV_CAPS_IN_CRC)
 #define DIGITAL_DRV_CAPS_TG_CRC(ddev) \
@@ -72,6 +79,13 @@ int digital_target_found(struct nfc_digital_dev *ddev,
 
 int digital_in_recv_mifare_res(struct sk_buff *resp);
 
+int digital_in_send_atr_req(struct nfc_digital_dev *ddev,
+			    struct nfc_target *target, __u8 comm_mode, __u8 *gb,
+			    size_t gb_len);
+int digital_in_send_dep_req(struct nfc_digital_dev *ddev,
+			    struct nfc_target *target, struct sk_buff *skb,
+			    struct digital_data_exch *data_exch);
+
 typedef u16 (*crc_func_t)(u16, const u8 *, size_t);
 
 #define CRC_A_INIT 0x6363

net/nfc/digital_core.c

@@ -18,9 +18,10 @@
 #include "digital.h"
 
 #define DIGITAL_PROTO_NFCA_RF_TECH \
-	(NFC_PROTO_JEWEL_MASK | NFC_PROTO_MIFARE_MASK)
+	(NFC_PROTO_JEWEL_MASK | NFC_PROTO_MIFARE_MASK | NFC_PROTO_NFC_DEP_MASK)
 
-#define DIGITAL_PROTO_NFCF_RF_TECH (NFC_PROTO_FELICA_MASK)
+#define DIGITAL_PROTO_NFCF_RF_TECH \
+	(NFC_PROTO_FELICA_MASK | NFC_PROTO_NFC_DEP_MASK)
 
 struct digital_cmd {
 	struct list_head queue;
@@ -260,6 +261,18 @@ int digital_target_found(struct nfc_digital_dev *ddev,
 		add_crc = digital_skb_add_crc_f;
 		break;
 
+	case NFC_PROTO_NFC_DEP:
+		if (rf_tech == NFC_DIGITAL_RF_TECH_106A) {
+			framing = NFC_DIGITAL_FRAMING_NFCA_NFC_DEP;
+			check_crc = digital_skb_check_crc_a;
+			add_crc = digital_skb_add_crc_a;
+		} else {
+			framing = NFC_DIGITAL_FRAMING_NFCF_NFC_DEP;
+			check_crc = digital_skb_check_crc_f;
+			add_crc = digital_skb_add_crc_f;
+		}
+		break;
+
 	default:
 		PR_ERR("Invalid protocol %d", protocol);
 		return -EINVAL;
@@ -453,12 +466,18 @@ static int digital_dep_link_up(struct nfc_dev *nfc_dev,
 			       struct nfc_target *target,
 			       __u8 comm_mode, __u8 *gb, size_t gb_len)
 {
-	return -EOPNOTSUPP;
+	struct nfc_digital_dev *ddev = nfc_get_drvdata(nfc_dev);
+
+	return digital_in_send_atr_req(ddev, target, comm_mode, gb, gb_len);
 }
 
 static int digital_dep_link_down(struct nfc_dev *nfc_dev)
 {
-	return -EOPNOTSUPP;
+	struct nfc_digital_dev *ddev = nfc_get_drvdata(nfc_dev);
+
+	ddev->curr_protocol = 0;
+
+	return 0;
 }
 
 static int digital_activate_target(struct nfc_dev *nfc_dev,
@@ -523,6 +542,9 @@ static int digital_in_send(struct nfc_dev *nfc_dev, struct nfc_target *target,
 	data_exch->cb = cb;
 	data_exch->cb_context = cb_context;
 
+	if (ddev->curr_protocol == NFC_PROTO_NFC_DEP)
+		return digital_in_send_dep_req(ddev, target, skb, data_exch);
+
 	ddev->skb_add_crc(skb);
 
 	return digital_in_send_cmd(ddev, skb, 500, digital_in_send_complete,
@@ -578,6 +600,8 @@ struct nfc_digital_dev *nfc_digital_allocate_device(struct nfc_digital_ops *ops,
 		ddev->protocols |= NFC_PROTO_MIFARE_MASK;
 	if (supported_protocols & NFC_PROTO_FELICA_MASK)
 		ddev->protocols |= NFC_PROTO_FELICA_MASK;
+	if (supported_protocols & NFC_PROTO_NFC_DEP_MASK)
+		ddev->protocols |= NFC_PROTO_NFC_DEP_MASK;
 
 	ddev->tx_headroom = tx_headroom + DIGITAL_MAX_HEADER_LEN;
 	ddev->tx_tailroom = tx_tailroom + DIGITAL_CRC_LEN;