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NFC: digital: Add NFC-DEP Initiator-side ATN Support

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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: Thierry Escande <thierry.escande@linux.intel.com>
Tested-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
This commit is contained in:
Mark A. Greer 2014-09-23 16:38:13 -07:00 committed by Samuel Ortiz
parent 49dbb14e30
commit 384ab1d174
2 changed files with 99 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/net/nfc/digital.h
View File

@ -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;

104
net/nfc/digital_dep.c
View File

@ -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;
goto error;
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 @@ error:
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;