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Commit 384ab1d1 authored by Mark A. Greer's avatar Mark A. Greer Committed by Samuel Ortiz
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NFC: digital: Add NFC-DEP Initiator-side ATN Support 



When an NFC-DEP Initiator times out when waiting for
a DEP_RES from the Target, its supposed to send an
ATN to the Target.  The Target should respond to the
ATN with a similar ATN PDU and the Initiator can then
resend the last non-ATN PDU that it sent.  No more
than 'N(retry,atn)' are to be send where
2 <= 'N(retry,atn)' <= 5.  If the Initiator had just
sent a NACK PDU when the timeout occurred, it is to
continue sending NACKs until 'N(retry,nack)' NACKs
have been send.  This is described in section
14.12.5.6 of the NFC-DEP Digital Protocol Spec.

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

The value chosen for 'N(retry,atn)' is 2.

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 49dbb14e

include/net/nfc/digital.h

+1 −0
Original line number Diff line number Diff line
@@ -233,6 +233,7 @@ struct nfc_digital_dev { 
	struct sk_buff *chaining_skb;

	struct digital_data_exch *data_exch;



	int atn_count;

	int nack_count;



	struct sk_buff *saved_skb;

net/nfc/digital_dep.c

+98 −6
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include "digital.h"



#define DIGITAL_NFC_DEP_N_RETRY_NACK	2

#define DIGITAL_NFC_DEP_N_RETRY_ATN	2



#define DIGITAL_NFC_DEP_FRAME_DIR_OUT 0xD4

#define DIGITAL_NFC_DEP_FRAME_DIR_IN  0xD5
@@ -523,10 +524,16 @@ static int digital_in_send_ack(struct nfc_digital_dev *ddev, 


	ddev->skb_add_crc(skb);



	ddev->saved_skb = skb_get(skb);

	ddev->saved_skb_len = skb->len;



	rc = digital_in_send_cmd(ddev, skb, 1500, digital_in_recv_dep_res,

				 data_exch);

	if (rc)

	if (rc) {

		kfree_skb(skb);

		kfree_skb(ddev->saved_skb);

		ddev->saved_skb = NULL;

	}



	return rc;

}
@@ -563,6 +570,37 @@ static int digital_in_send_nack(struct nfc_digital_dev *ddev, 
	return rc;

}



static int digital_in_send_atn(struct nfc_digital_dev *ddev,

			       struct digital_data_exch *data_exch)

{

	struct digital_dep_req_res *dep_req;

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



	dep_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;

	dep_req->cmd = DIGITAL_CMD_DEP_REQ;

	dep_req->pfb = DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU;



	digital_skb_push_dep_sod(ddev, skb);



	ddev->skb_add_crc(skb);



	rc = digital_in_send_cmd(ddev, skb, 1500, digital_in_recv_dep_res,

				 data_exch);

	if (rc)

		kfree_skb(skb);



	return rc;

}



static int digital_in_send_rtox(struct nfc_digital_dev *ddev,

				struct digital_data_exch *data_exch, u8 rtox)

{
@@ -589,14 +627,30 @@ static int digital_in_send_rtox(struct nfc_digital_dev *ddev, 


	ddev->skb_add_crc(skb);



	ddev->saved_skb = skb_get(skb);

	ddev->saved_skb_len = skb->len;



	rc = digital_in_send_cmd(ddev, skb, 1500, digital_in_recv_dep_res,

				 data_exch);

	if (rc)

	if (rc) {

		kfree_skb(skb);

		kfree_skb(ddev->saved_skb);

		ddev->saved_skb = NULL;

	}



	return rc;

}



static int digital_in_send_saved_skb(struct nfc_digital_dev *ddev,

				     struct digital_data_exch *data_exch)

{

	skb_get(ddev->saved_skb);

	skb_push(ddev->saved_skb, ddev->saved_skb_len);



	return digital_in_send_cmd(ddev, ddev->saved_skb, 1500,

				   digital_in_recv_dep_res, data_exch);

}



static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,

				    struct sk_buff *resp)

{
@@ -610,12 +664,23 @@ static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg, 
		rc = PTR_ERR(resp);

		resp = NULL;



		if ((rc != -ETIMEDOUT) &&

		if (((rc != -ETIMEDOUT) || ddev->nack_count) &&

		    (ddev->nack_count++ < DIGITAL_NFC_DEP_N_RETRY_NACK)) {

			ddev->atn_count = 0;



			rc = digital_in_send_nack(ddev, data_exch);

			if (rc)

				goto error;



			return;

		} else if ((rc == -ETIMEDOUT) &&

			   (ddev->atn_count++ < DIGITAL_NFC_DEP_N_RETRY_ATN)) {

			ddev->nack_count = 0;



			rc = digital_in_send_atn(ddev, data_exch);

			if (rc)

				goto error;



			return;

		}
@@ -632,6 +697,8 @@ static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg, 
	if (rc) {

		if ((resp->len >= 4) &&

		    (ddev->nack_count++ < DIGITAL_NFC_DEP_N_RETRY_NACK)) {

			ddev->atn_count = 0;



			rc = digital_in_send_nack(ddev, data_exch);

			if (rc)

				goto error;
@@ -645,6 +712,7 @@ static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg, 
		goto error;

	}



	ddev->atn_count = 0;

	ddev->nack_count = 0;



	if (resp->len > ddev->local_payload_max) {
@@ -692,6 +760,9 @@ static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg, 
		ddev->curr_nfc_dep_pni =

			DIGITAL_NFC_DEP_PFB_PNI(ddev->curr_nfc_dep_pni + 1);



		kfree_skb(ddev->saved_skb);

		ddev->saved_skb = NULL;



		resp = digital_recv_dep_data_gather(ddev, pfb, resp,

						    digital_in_send_ack,

						    data_exch);
@@ -722,6 +793,9 @@ static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg, 
			DIGITAL_NFC_DEP_PFB_PNI(ddev->curr_nfc_dep_pni + 1);



		if (ddev->chaining_skb && !DIGITAL_NFC_DEP_NACK_BIT_SET(pfb)) {

			kfree_skb(ddev->saved_skb);

			ddev->saved_skb = NULL;



			rc = digital_in_send_dep_req(ddev, NULL,

						     ddev->chaining_skb,

						     ddev->data_exch);
@@ -736,11 +810,19 @@ static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg, 
		goto exit;



	case DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU:

		if (!DIGITAL_NFC_DEP_PFB_IS_TIMEOUT(pfb)) {

			rc = -EINVAL;

		if (!DIGITAL_NFC_DEP_PFB_IS_TIMEOUT(pfb)) { /* ATN */

			rc = digital_in_send_saved_skb(ddev, data_exch);

			if (rc) {

				kfree_skb(ddev->saved_skb);

				goto error;

			}



			return;

		}



		kfree_skb(ddev->saved_skb);

		ddev->saved_skb = NULL;



		rc = digital_in_send_rtox(ddev, data_exch, resp->data[0]);

		if (rc)

			goto error;
@@ -758,6 +840,9 @@ static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg, 
	kfree_skb(ddev->chaining_skb);

	ddev->chaining_skb = NULL;



	kfree_skb(ddev->saved_skb);

	ddev->saved_skb = NULL;



	if (rc)

		kfree_skb(resp);

}
@@ -778,6 +863,7 @@ int digital_in_send_dep_req(struct nfc_digital_dev *ddev, 
	dep_req->cmd = DIGITAL_CMD_DEP_REQ;

	dep_req->pfb = ddev->curr_nfc_dep_pni;



	ddev->atn_count = 0;

	ddev->nack_count = 0;



	chaining_skb = ddev->chaining_skb;
@@ -790,6 +876,9 @@ int digital_in_send_dep_req(struct nfc_digital_dev *ddev, 


	ddev->skb_add_crc(tmp_skb);



	ddev->saved_skb = skb_get(tmp_skb);

	ddev->saved_skb_len = tmp_skb->len;



	rc = digital_in_send_cmd(ddev, tmp_skb, 1500, digital_in_recv_dep_res,

				 data_exch);

	if (rc) {
@@ -798,6 +887,9 @@ int digital_in_send_dep_req(struct nfc_digital_dev *ddev, 


		kfree_skb(chaining_skb);

		ddev->chaining_skb = NULL;



		kfree_skb(ddev->saved_skb);

		ddev->saved_skb = NULL;

	}



	return rc;