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Commit 9b5ec0fd authored by Mark A. Greer's avatar Mark A. Greer Committed by Samuel Ortiz
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NFC: digital: Add NFC-DEP Target-side ATN Support 



When an NFC-DEP target receives an ATN PDU, its
supposed to respond with a similar ATN PDU.
When the Target receives an I PDU with the PNI
one less than the current PNI and the last PDU
sent was an ATN PDU, the Target is to resend the
last non-ATN PDU that it has sent.  This is
described in section 14.12.3.4 of the NFC Digital
Protocol Spec.

The digital layer's NFC-DEP code doesn't implement
this so add that support.

Reviewed-by: default avatarThierry Escande <thierry.escande@linux.intel.com>
Tested-by: default avatarThierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: default avatarMark A. Greer <mgreer@animalcreek.com>
Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
parent 384ab1d1

net/nfc/digital_dep.c

+83 −5
Original line number Diff line number Diff line
@@ -970,6 +970,43 @@ static int digital_tg_send_ack(struct nfc_digital_dev *ddev, 
	return rc;

}



static int digital_tg_send_atn(struct nfc_digital_dev *ddev)

{

	struct digital_dep_req_res *dep_res;

	struct sk_buff *skb;

	int rc;



	skb = digital_skb_alloc(ddev, 1);

	if (!skb)

		return -ENOMEM;



	skb_push(skb, sizeof(struct digital_dep_req_res));



	dep_res = (struct digital_dep_req_res *)skb->data;



	dep_res->dir = DIGITAL_NFC_DEP_FRAME_DIR_IN;

	dep_res->cmd = DIGITAL_CMD_DEP_RES;

	dep_res->pfb = DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU;



	if (ddev->did) {

		dep_res->pfb |= DIGITAL_NFC_DEP_PFB_DID_BIT;



		memcpy(skb_put(skb, sizeof(ddev->did)), &ddev->did,

		       sizeof(ddev->did));

	}



	digital_skb_push_dep_sod(ddev, skb);



	ddev->skb_add_crc(skb);



	rc = digital_tg_send_cmd(ddev, skb, 1500, digital_tg_recv_dep_req,

				 NULL);

	if (rc)

		kfree_skb(skb);



	return rc;

}



static int digital_tg_send_saved_skb(struct nfc_digital_dev *ddev)

{

	skb_get(ddev->saved_skb);
@@ -1049,12 +1086,24 @@ static void digital_tg_recv_dep_req(struct nfc_digital_dev *ddev, void *arg, 
	case DIGITAL_NFC_DEP_PFB_I_PDU:

		pr_debug("DIGITAL_NFC_DEP_PFB_I_PDU\n");



		if (DIGITAL_NFC_DEP_PFB_PNI(pfb) != ddev->curr_nfc_dep_pni) {

		if ((ddev->atn_count && (DIGITAL_NFC_DEP_PFB_PNI(pfb - 1) !=

						ddev->curr_nfc_dep_pni)) ||

		    (DIGITAL_NFC_DEP_PFB_PNI(pfb) != ddev->curr_nfc_dep_pni)) {

			PROTOCOL_ERR("14.12.3.4");

			rc = -EIO;

			goto exit;

		}



		if (ddev->atn_count) {

			ddev->atn_count = 0;



			rc = digital_tg_send_saved_skb(ddev);

			if (rc)

				goto exit;



			return;

		}



		kfree_skb(ddev->saved_skb);

		ddev->saved_skb = NULL;
@@ -1077,13 +1126,26 @@ static void digital_tg_recv_dep_req(struct nfc_digital_dev *ddev, void *arg, 
		break;

	case DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU:

		if (!DIGITAL_NFC_DEP_NACK_BIT_SET(pfb)) { /* ACK */

			if ((DIGITAL_NFC_DEP_PFB_PNI(pfb) !=

			if ((ddev->atn_count &&

			     (DIGITAL_NFC_DEP_PFB_PNI(pfb - 1) !=

						ddev->curr_nfc_dep_pni)) ||

			    (DIGITAL_NFC_DEP_PFB_PNI(pfb) !=

						ddev->curr_nfc_dep_pni) ||

			    !ddev->chaining_skb || !ddev->saved_skb) {

				rc = -EIO;

				goto exit;

			}



			if (ddev->atn_count) {

				ddev->atn_count = 0;



				rc = digital_tg_send_saved_skb(ddev);

				if (rc)

					goto exit;



				return;

			}



			kfree_skb(ddev->saved_skb);

			ddev->saved_skb = NULL;
@@ -1098,6 +1160,8 @@ static void digital_tg_recv_dep_req(struct nfc_digital_dev *ddev, void *arg, 
				goto exit;

			}



			ddev->atn_count = 0;



			rc = digital_tg_send_saved_skb(ddev);

			if (rc) {

				kfree_skb(ddev->saved_skb);
@@ -1107,17 +1171,29 @@ static void digital_tg_recv_dep_req(struct nfc_digital_dev *ddev, void *arg, 


		return;

	case DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU:

		pr_err("Received a SUPERVISOR PDU\n");

		if (DIGITAL_NFC_DEP_PFB_IS_TIMEOUT(pfb)) {

			rc = -EINVAL;

			goto exit;

		}



		rc = digital_tg_send_atn(ddev);

		if (rc)

			goto exit;



		ddev->atn_count++;



		kfree_skb(resp);

		return;

	}



	rc = nfc_tm_data_received(ddev->nfc_dev, resp);



exit:

	kfree_skb(ddev->chaining_skb);

	ddev->chaining_skb = NULL;



	ddev->atn_count = 0;



	kfree_skb(ddev->saved_skb);

	ddev->saved_skb = NULL;
@@ -1311,6 +1387,8 @@ static void digital_tg_send_atr_res_complete(struct nfc_digital_dev *ddev, 
	if (resp->data[0] == DIGITAL_NFC_DEP_NFCA_SOD_SB)

		offset++;



	ddev->atn_count = 0;



	if (resp->data[offset] == DIGITAL_CMD_PSL_REQ)

		digital_tg_recv_psl_req(ddev, arg, resp);

	else