NFC: pn533: Add frame header length define

PN533_CMD_DATAEXCH_HEAD_LEN includes a frame header length which is not
seen at a glance. It can be missleading, so split it and define the
frame header length explicitly.

Signed-off-by: Waldemar Rymarkiewicz <waldemar.rymarkiewicz@tieto.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

diff --git a/drivers/nfc/pn533.c b/drivers/nfc/pn533.c
index ed8ecb3..7040106 100644 (file)
--- a/drivers/nfc/pn533.c
+++ b/drivers/nfc/pn533.c
@@ -82,10 +82,12 @@ MODULE_DEVICE_TABLE(usb, pn533_table);
 #define PN533_NORMAL_FRAME_MAX_LEN 262  /* 6   (PREAMBLE, SOF, LEN, LCS, TFI)
                                           254 (DATA)
                                           2   (DCS, postamble) */
+#define PN533_FRAME_HEADER_LEN (sizeof(struct pn533_frame) \
+                                       + 2) /* data[0] TFI, data[1] CC */
+#define PN533_FRAME_TAIL_LEN 2 /* data[len] DCS, data[len + 1] postamble*/
 
-#define PN533_FRAME_TAIL_SIZE 2
 #define PN533_FRAME_SIZE(f) (sizeof(struct pn533_frame) + f->datalen + \
-                               PN533_FRAME_TAIL_SIZE)
+                               PN533_FRAME_TAIL_LEN)
 #define PN533_FRAME_ACK_SIZE (sizeof(struct pn533_frame) + 1)
 #define PN533_FRAME_CHECKSUM(f) (f->data[f->datalen])
 #define PN533_FRAME_POSTAMBLE(f) (f->data[f->datalen + 1])
@@ -1233,7 +1235,7 @@ static int pn533_init_target_frame(struct pn533_frame *frame,
        return 0;
 }
 
-#define PN533_CMD_DATAEXCH_HEAD_LEN (sizeof(struct pn533_frame) + 3)
+#define PN533_CMD_DATAEXCH_HEAD_LEN 1
 #define PN533_CMD_DATAEXCH_DATA_MAXLEN 262
 static int pn533_tm_get_data_complete(struct pn533 *dev, void *arg,
                                      u8 *params, int params_len)
@@ -1261,8 +1263,9 @@ static int pn533_tm_get_data_complete(struct pn533 *dev, void *arg,
        }
 
        skb_put(skb_resp, PN533_FRAME_SIZE(in_frame));
-       skb_pull(skb_resp, PN533_CMD_DATAEXCH_HEAD_LEN);
-       skb_trim(skb_resp, skb_resp->len - PN533_FRAME_TAIL_SIZE);
+       skb_pull(skb_resp,
+                PN533_FRAME_HEADER_LEN + PN533_CMD_DATAEXCH_HEAD_LEN);
+       skb_trim(skb_resp, skb_resp->len - PN533_FRAME_TAIL_LEN);
 
        return nfc_tm_data_received(dev->nfc_dev, skb_resp);
 }
@@ -1276,9 +1279,10 @@ static void pn533_wq_tg_get_data(struct work_struct *work)
 
        nfc_dev_dbg(&dev->interface->dev, "%s", __func__);
 
-       skb_resp_len = PN533_CMD_DATAEXCH_HEAD_LEN +
-               PN533_CMD_DATAEXCH_DATA_MAXLEN +
-               PN533_FRAME_TAIL_SIZE;
+       skb_resp_len = PN533_FRAME_HEADER_LEN +
+                      PN533_CMD_DATAEXCH_HEAD_LEN +
+                      PN533_CMD_DATAEXCH_DATA_MAXLEN +
+                      PN533_FRAME_TAIL_LEN;
 
        skb_resp = nfc_alloc_recv_skb(skb_resp_len, GFP_KERNEL);
        if (!skb_resp)
@@ -1859,11 +1863,12 @@ static int pn533_build_tx_frame(struct pn533 *dev, struct sk_buff *skb,
                return -ENOSYS;
        }
 
+       skb_push(skb, PN533_FRAME_HEADER_LEN);
+
        if (target == true) {
                switch (dev->device_type) {
                case PN533_DEVICE_PASORI:
                        if (dev->tgt_active_prot == NFC_PROTO_FELICA) {
-                               skb_push(skb, PN533_CMD_DATAEXCH_HEAD_LEN - 1);
                                out_frame = (struct pn533_frame *) skb->data;
                                pn533_tx_frame_init(out_frame,
                                                    PN533_CMD_IN_COMM_THRU);
@@ -1895,7 +1900,7 @@ static int pn533_build_tx_frame(struct pn533 *dev, struct sk_buff *skb,
        out_frame->datalen += payload_len;
 
        pn533_tx_frame_finish(out_frame);
-       skb_put(skb, PN533_FRAME_TAIL_SIZE);
+       skb_put(skb, PN533_FRAME_TAIL_LEN);
 
        return 0;
 }
@@ -1975,8 +1980,9 @@ static int pn533_data_exchange_complete(struct pn533 *dev, void *_arg,
        }
 
        skb_put(skb_resp, PN533_FRAME_SIZE(in_frame));
+       skb_pull(skb_resp, PN533_FRAME_HEADER_LEN);
        skb_pull(skb_resp, PN533_CMD_DATAEXCH_HEAD_LEN);
-       skb_trim(skb_resp, skb_resp->len - PN533_FRAME_TAIL_SIZE);
+       skb_trim(skb_resp, skb_resp->len - PN533_FRAME_TAIL_LEN);
        skb_queue_tail(&dev->resp_q, skb_resp);
 
        if (status & PN533_CMD_MI_MASK) {
@@ -2024,9 +2030,10 @@ static int pn533_transceive(struct nfc_dev *nfc_dev,
        if (rc)
                goto error;
 
-       skb_resp_len = PN533_CMD_DATAEXCH_HEAD_LEN +
-                       PN533_CMD_DATAEXCH_DATA_MAXLEN +
-                       PN533_FRAME_TAIL_SIZE;
+       skb_resp_len = PN533_FRAME_HEADER_LEN +
+                      PN533_CMD_DATAEXCH_HEAD_LEN +
+                      PN533_CMD_DATAEXCH_DATA_MAXLEN +
+                      PN533_FRAME_TAIL_LEN;
 
        skb_resp = nfc_alloc_recv_skb(skb_resp_len, GFP_KERNEL);
        if (!skb_resp) {
@@ -2143,20 +2150,25 @@ static void pn533_wq_mi_recv(struct work_struct *work)
        nfc_dev_dbg(&dev->interface->dev, "%s", __func__);
 
        /* This is a zero payload size skb */
-       skb_cmd = alloc_skb(PN533_CMD_DATAEXCH_HEAD_LEN + PN533_FRAME_TAIL_SIZE,
+       skb_cmd = alloc_skb(PN533_FRAME_HEADER_LEN +
+                           PN533_CMD_DATAEXCH_HEAD_LEN +
+                           PN533_FRAME_TAIL_LEN,
                            GFP_KERNEL);
        if (skb_cmd == NULL)
                goto error_cmd;
 
-       skb_reserve(skb_cmd, PN533_CMD_DATAEXCH_HEAD_LEN);
+       skb_reserve(skb_cmd,
+                   PN533_FRAME_HEADER_LEN + PN533_CMD_DATAEXCH_HEAD_LEN);
 
        rc = pn533_build_tx_frame(dev, skb_cmd, true);
        if (rc)
                goto error_frame;
 
-       skb_resp_len = PN533_CMD_DATAEXCH_HEAD_LEN +
-                       PN533_CMD_DATAEXCH_DATA_MAXLEN +
-                       PN533_FRAME_TAIL_SIZE;
+       skb_resp_len = PN533_FRAME_HEADER_LEN +
+                      PN533_CMD_DATAEXCH_HEAD_LEN +
+                      PN533_CMD_DATAEXCH_DATA_MAXLEN +
+                      PN533_FRAME_TAIL_LEN;
+
        skb_resp = alloc_skb(skb_resp_len, GFP_KERNEL);
        if (!skb_resp) {
                rc = -ENOMEM;
@@ -2433,8 +2445,9 @@ static int pn533_probe(struct usb_interface *interface,
        }
 
        dev->nfc_dev = nfc_allocate_device(&pn533_nfc_ops, protocols,
+                                          PN533_FRAME_HEADER_LEN +
                                           PN533_CMD_DATAEXCH_HEAD_LEN,
-                                          PN533_FRAME_TAIL_SIZE);
+                                          PN533_FRAME_TAIL_LEN);
        if (!dev->nfc_dev)
                goto destroy_wq;