commit 9dbe776338e7f97483452cc00adf0d527d6900dd
author Christophe Ricard <christophe.ricard@gmail.com> Tue Mar 31 08:02:23 2015 +0200
committer Samuel Ortiz <sameo@linux.intel.com> Mon Apr 06 00:21:10 2015 +0200
tree 02ff8fc21e50a819411c10f7170c83024d98c29c
parent 1dab57f0ed753ddef07a8aa987d490c74884ff18

nfc: st21nfca: Add additional comments about EVT_TRANSACTION

Add comments about HCI EVT_TRANSACTION in order to make the code
understandable by other readers.

Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/nfc/st21nfca/st21nfca_se.c

diff --git a/drivers/nfc/st21nfca/st21nfca_se.c b/drivers/nfc/st21nfca/st21nfca_se.c
index bd13cac..3197e9b 100644
--- a/drivers/nfc/st21nfca/st21nfca_se.c
+++ b/drivers/nfc/st21nfca/st21nfca_se.c
@@ -310,6 +310,13 @@
 	case ST21NFCA_EVT_CONNECTIVITY:
 		break;
 	case ST21NFCA_EVT_TRANSACTION:
+		/*
+		 * According to specification etsi 102 622
+		 * 11.2.2.4 EVT_TRANSACTION Table 52
+		 * Description	Tag	Length
+		 * AID		81	5 to 16
+		 * PARAMETERS	82	0 to 255
+		 */
 		if (skb->len < NFC_MIN_AID_LENGTH + 2 &&
 		    skb->data[0] != NFC_EVT_TRANSACTION_AID_TAG)
 			return -EPROTO;
@@ -318,8 +325,10 @@
 						   skb->len - 2, GFP_KERNEL);
 
 		transaction->aid_len = skb->data[1];
-		memcpy(transaction->aid, &skb->data[2], skb->data[1]);
+		memcpy(transaction->aid, &skb->data[2],
+		       transaction->aid_len);
 
+		/* Check next byte is PARAMETERS tag (82) */
 		if (skb->data[transaction->aid_len + 2] !=
 		    NFC_EVT_TRANSACTION_PARAMS_TAG)
 			return -EPROTO;