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Commit 1a09c56f authored by Thierry Escande's avatar Thierry Escande Committed by Samuel Ortiz
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NFC: digital: Add support for NFC DEP Response Waiting Time 



When sending an ATR_REQ, the initiator must wait for the ATR_RES at
least 'RWT(nfcdep,activation) + dRWT(nfcdep)' and no more than
'RWT(nfcdep,activation) + dRWT(nfcdep) + dT(nfcdep,initiator)'. This
gives a timeout value between 1237 ms and 1337 ms. This patch defines
DIGITAL_ATR_RES_RWT to 1337 used for the timeout value of ATR_REQ
command.

For other DEP PDUs, the initiator must wait between 'RWT + dRWT(nfcdep)'
and 'RWT + dRWT(nfcdep) + dT(nfcdep,initiator)' where RWT is given by
the following formula: '(256 * 16 / f(c)) * 2^wt' where wt is the value
of the TO field in the ATR_RES response and is in the range between 0
and 14. This patch declares a mapping table for wt values and gives RWT
max values between 100 ms and 5049 ms.

This patch also defines DIGITAL_ATR_RES_TO_WT, the maximum wt value in
target mode, to 8.

Signed-off-by: default avatarThierry Escande <thierry.escande@collabora.com>
Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
parent e200f008

include/net/nfc/digital.h

+1 −0
Original line number Diff line number Diff line
@@ -226,6 +226,7 @@ struct nfc_digital_dev { 
	u8 curr_rf_tech;

	u8 curr_nfc_dep_pni;

	u8 did;

	u16 dep_rwt;



	u8 local_payload_max;

	u8 remote_payload_max;

net/nfc/digital_dep.c

+55 −16
Original line number Diff line number Diff line
@@ -35,6 +35,8 @@ 
#define DIGITAL_ATR_REQ_MIN_SIZE 16

#define DIGITAL_ATR_REQ_MAX_SIZE 64



#define DIGITAL_ATR_RES_TO_WT(s)	((s) & 0xF)



#define DIGITAL_DID_MAX	14



#define DIGITAL_PAYLOAD_SIZE_MAX	254
@@ -122,6 +124,37 @@ static const u8 digital_payload_bits_map[4] = { 
	[3] = 254

};



/* Response Waiting Time for ATR_RES PDU in ms

 *

 * RWT(ATR_RES) = RWT(nfcdep,activation) + dRWT(nfcdep) + dT(nfcdep,initiator)

 *

 * with:

 *  RWT(nfcdep,activation) = 4096 * 2^12 / f(c) s

 *  dRWT(nfcdep) = 16 / f(c) s

 *  dT(nfcdep,initiator) = 100 ms

 *  f(c) = 13560000 Hz

 */

#define DIGITAL_ATR_RES_RWT 1337



/* Response Waiting Time for other DEP PDUs in ms

 *

 * max_rwt = rwt + dRWT(nfcdep) + dT(nfcdep,initiator)

 *

 * with:

 *  rwt = (256 * 16 / f(c)) * 2^wt s

 *  dRWT(nfcdep) = 16 / f(c) s

 *  dT(nfcdep,initiator) = 100 ms

 *  f(c) = 13560000 Hz

 *  0 <= wt <= 14 (given by the target by the TO field of ATR_RES response)

 */

#define DIGITAL_NFC_DEP_IN_MAX_WT 14

#define DIGITAL_NFC_DEP_TG_MAX_WT 8

static const u16 digital_rwt_map[DIGITAL_NFC_DEP_IN_MAX_WT + 1] = {

	100,  101,  101,  102,  105,

	110,  119,  139,  177,  255,

	409,  719, 1337, 2575, 5049,

};



static u8 digital_payload_bits_to_size(u8 payload_bits)

{

	if (payload_bits >= ARRAY_SIZE(digital_payload_bits_map))
@@ -366,8 +399,8 @@ static int digital_in_send_psl_req(struct nfc_digital_dev *ddev, 


	ddev->skb_add_crc(skb);



	rc = digital_in_send_cmd(ddev, skb, 500, digital_in_recv_psl_res,

				 target);

	rc = digital_in_send_cmd(ddev, skb, ddev->dep_rwt,

				 digital_in_recv_psl_res, target);

	if (rc)

		kfree_skb(skb);
@@ -380,6 +413,7 @@ static void digital_in_recv_atr_res(struct nfc_digital_dev *ddev, void *arg, 
	struct nfc_target *target = arg;

	struct digital_atr_res *atr_res;

	u8 gb_len, payload_bits;

	u8 wt;

	int rc;



	if (IS_ERR(resp)) {
@@ -409,6 +443,11 @@ static void digital_in_recv_atr_res(struct nfc_digital_dev *ddev, void *arg, 


	atr_res = (struct digital_atr_res *)resp->data;



	wt = DIGITAL_ATR_RES_TO_WT(atr_res->to);

	if (wt > DIGITAL_NFC_DEP_IN_MAX_WT)

		wt = DIGITAL_NFC_DEP_IN_MAX_WT;

	ddev->dep_rwt = digital_rwt_map[wt];



	payload_bits = DIGITAL_PAYLOAD_PP_TO_BITS(atr_res->pp);

	ddev->remote_payload_max = digital_payload_bits_to_size(payload_bits);
@@ -490,8 +529,8 @@ int digital_in_send_atr_req(struct nfc_digital_dev *ddev, 


	ddev->skb_add_crc(skb);



	rc = digital_in_send_cmd(ddev, skb, 500, digital_in_recv_atr_res,

				 target);

	rc = digital_in_send_cmd(ddev, skb, DIGITAL_ATR_RES_RWT,

				 digital_in_recv_atr_res, target);

	if (rc)

		kfree_skb(skb);
@@ -524,8 +563,8 @@ static int digital_in_send_ack(struct nfc_digital_dev *ddev, 


	ddev->saved_skb = pskb_copy(skb, GFP_KERNEL);



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

				 data_exch);

	rc = digital_in_send_cmd(ddev, skb, ddev->dep_rwt,

				 digital_in_recv_dep_res, data_exch);

	if (rc) {

		kfree_skb(skb);

		kfree_skb(ddev->saved_skb);
@@ -559,8 +598,8 @@ static int digital_in_send_nack(struct nfc_digital_dev *ddev, 


	ddev->skb_add_crc(skb);



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

				 data_exch);

	rc = digital_in_send_cmd(ddev, skb, ddev->dep_rwt,

				 digital_in_recv_dep_res, data_exch);

	if (rc)

		kfree_skb(skb);
@@ -590,8 +629,8 @@ static int digital_in_send_atn(struct nfc_digital_dev *ddev, 


	ddev->skb_add_crc(skb);



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

				 data_exch);

	rc = digital_in_send_cmd(ddev, skb, ddev->dep_rwt,

				 digital_in_recv_dep_res, data_exch);

	if (rc)

		kfree_skb(skb);
@@ -624,8 +663,8 @@ static int digital_in_send_rtox(struct nfc_digital_dev *ddev, 


	ddev->skb_add_crc(skb);



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

				 data_exch);

	rc = digital_in_send_cmd(ddev, skb, ddev->dep_rwt,

				 digital_in_recv_dep_res, data_exch);

	if (rc)

		kfree_skb(skb);
@@ -642,7 +681,7 @@ static int digital_in_send_saved_skb(struct nfc_digital_dev *ddev, 


	skb_get(ddev->saved_skb);



	rc = digital_in_send_cmd(ddev, ddev->saved_skb, 1500,

	rc = digital_in_send_cmd(ddev, ddev->saved_skb, ddev->dep_rwt,

				 digital_in_recv_dep_res, data_exch);

	if (rc)

		kfree_skb(ddev->saved_skb);
@@ -885,8 +924,8 @@ int digital_in_send_dep_req(struct nfc_digital_dev *ddev, 


	ddev->saved_skb = pskb_copy(tmp_skb, GFP_KERNEL);



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

				 data_exch);

	rc = digital_in_send_cmd(ddev, tmp_skb, ddev->dep_rwt,

				 digital_in_recv_dep_res, data_exch);

	if (rc) {

		if (tmp_skb != skb)

			kfree_skb(tmp_skb);
@@ -1465,7 +1504,7 @@ static int digital_tg_send_atr_res(struct nfc_digital_dev *ddev, 
	atr_res->dir = DIGITAL_NFC_DEP_FRAME_DIR_IN;

	atr_res->cmd = DIGITAL_CMD_ATR_RES;

	memcpy(atr_res->nfcid3, atr_req->nfcid3, sizeof(atr_req->nfcid3));

	atr_res->to = 8;

	atr_res->to = DIGITAL_NFC_DEP_TG_MAX_WT;



	ddev->local_payload_max = DIGITAL_PAYLOAD_SIZE_MAX;

	payload_bits = digital_payload_size_to_bits(ddev->local_payload_max);