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: 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>
diff --git a/net/nfc/digital_dep.c b/net/nfc/digital_dep.c
index 31418ed..8f1fefd 100644
--- a/net/nfc/digital_dep.c
+++ b/net/nfc/digital_dep.c
@@ -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 @@
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 @@
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 @@
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)
{
@@ -610,13 +664,24 @@
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;
}
goto exit;
@@ -632,6 +697,8 @@
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 @@
goto error;
}
+ ddev->atn_count = 0;
ddev->nack_count = 0;
if (resp->len > ddev->local_payload_max) {
@@ -692,6 +760,9 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
kfree_skb(chaining_skb);
ddev->chaining_skb = NULL;
+
+ kfree_skb(ddev->saved_skb);
+ ddev->saved_skb = NULL;
}
return rc;