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

1 files changed, 11 insertions, 1 deletions

diff --git a/net/nfc/digital_technology.c b/net/nfc/digital_technology.c
index bfe5ae17909..0c28f600fd1 100644
--- a/net/nfc/digital_technology.c
+++ b/net/nfc/digital_technology.c
@@ -28,6 +28,7 @@
 
 #define DIGITAL_SEL_RES_NFCID1_COMPLETE(sel_res) (!((sel_res) & 0x04))
 #define DIGITAL_SEL_RES_IS_T2T(sel_res) (!((sel_res) & 0x60))
+#define DIGITAL_SEL_RES_IS_NFC_DEP(sel_res) ((sel_res) & 0x40)
 
 #define DIGITAL_SENS_RES_IS_T1T(sens_res) (((sens_res) & 0x000C) == 0x000C)
 #define DIGITAL_SENS_RES_IS_VALID(sens_res) \
@@ -121,6 +122,8 @@ static void digital_in_recv_sel_res(struct nfc_digital_dev *ddev, void *arg,
 
 	if (DIGITAL_SEL_RES_IS_T2T(sel_res)) {
 		nfc_proto = NFC_PROTO_MIFARE;
+	} else if (DIGITAL_SEL_RES_IS_NFC_DEP(sel_res)) {
+		nfc_proto = NFC_PROTO_NFC_DEP;
 	} else {
 		rc = -EOPNOTSUPP;
 		goto exit;
@@ -379,6 +382,7 @@ static void digital_in_recv_sensf_res(struct nfc_digital_dev *ddev, void *arg,
 				   struct sk_buff *resp)
 {
 	int rc;
+	u8 proto;
 	struct nfc_target target;
 	struct digital_sensf_res *sensf_res;
 
@@ -413,7 +417,13 @@ static void digital_in_recv_sensf_res(struct nfc_digital_dev *ddev, void *arg,
 	memcpy(target.nfcid2, sensf_res->nfcid2, NFC_NFCID2_MAXSIZE);
 	target.nfcid2_len = NFC_NFCID2_MAXSIZE;
 
-	rc = digital_target_found(ddev, &target, NFC_PROTO_FELICA);
+	if (target.nfcid2[0] == DIGITAL_SENSF_NFCID2_NFC_DEP_B1 &&
+	    target.nfcid2[1] == DIGITAL_SENSF_NFCID2_NFC_DEP_B2)
+		proto = NFC_PROTO_NFC_DEP;
+	else
+		proto = NFC_PROTO_FELICA;
+
+	rc = digital_target_found(ddev, &target, proto);
 
 exit:
 	dev_kfree_skb(resp);