NFC: Remove crc generation from shdlc layer

Checksum is specific for a chip spcification and it varies
(in size and type) between different hardware. It should be
handled in the driver then.

Moreover, shdlc spec doesn't mention crc as a part of the frame.

Update pn544_hci driver as well.

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

diff --git a/drivers/nfc/pn544_hci.c b/drivers/nfc/pn544_hci.c
index 9458d53cdb59e85e1869da0b7f792613fdf6d437..d90aecfce73910357355863887f5aecd00822504 100644 (file)
--- a/drivers/nfc/pn544_hci.c
+++ b/drivers/nfc/pn544_hci.c
@@ -128,6 +128,8 @@ static struct nfc_hci_gate pn544_gates[] = {
 
 /* Largest headroom needed for outgoing custom commands */
 #define PN544_CMDS_HEADROOM    2
+#define PN544_FRAME_HEADROOM 1
+#define PN544_FRAME_TAILROOM 2
 
 struct pn544_hci_info {
        struct i2c_client *i2c_dev;
@@ -576,15 +578,40 @@ static int pn544_hci_ready(struct nfc_shdlc *shdlc)
        return 0;
 }
 
+static void pn544_hci_add_len_crc(struct sk_buff *skb)
+{
+       u16 crc;
+       int len;
+
+       len = skb->len + 2;
+       *skb_push(skb, 1) = len;
+
+       crc = crc_ccitt(0xffff, skb->data, skb->len);
+       crc = ~crc;
+       *skb_put(skb, 1) = crc & 0xff;
+       *skb_put(skb, 1) = crc >> 8;
+}
+
+static void pn544_hci_remove_len_crc(struct sk_buff *skb)
+{
+       skb_pull(skb, PN544_FRAME_HEADROOM);
+       skb_trim(skb, PN544_FRAME_TAILROOM);
+}
+
 static int pn544_hci_xmit(struct nfc_shdlc *shdlc, struct sk_buff *skb)
 {
        struct pn544_hci_info *info = nfc_shdlc_get_clientdata(shdlc);
        struct i2c_client *client = info->i2c_dev;
+       int r;
 
        if (info->hard_fault != 0)
                return info->hard_fault;
 
-       return pn544_hci_i2c_write(client, skb->data, skb->len);
+       pn544_hci_add_len_crc(skb);
+       r = pn544_hci_i2c_write(client, skb->data, skb->len);
+       pn544_hci_remove_len_crc(skb);
+
+       return r;
 }
 
 static int pn544_hci_start_poll(struct nfc_shdlc *shdlc,
@@ -874,7 +901,8 @@ static int __devinit pn544_hci_probe(struct i2c_client *client,
 
        info->shdlc = nfc_shdlc_allocate(&pn544_shdlc_ops,
                                         &init_data, protocols,
-                                        PN544_CMDS_HEADROOM, 0,
+                                        PN544_FRAME_HEADROOM + PN544_CMDS_HEADROOM,
+                                        PN544_FRAME_TAILROOM,
                                         PN544_HCI_LLC_MAX_PAYLOAD,
                                         dev_name(&client->dev));
        if (!info->shdlc) {

diff --git a/net/nfc/hci/shdlc.c b/net/nfc/hci/shdlc.c
index 824fb09384ed526abb6d6912c992e58f2c189295..ed8796b78f3993b604629f899af82b04d57cbb11 100644 (file)
--- a/net/nfc/hci/shdlc.c
+++ b/net/nfc/hci/shdlc.c
@@ -22,7 +22,6 @@
 #include <linux/sched.h>
 #include <linux/export.h>
 #include <linux/wait.h>
-#include <linux/crc-ccitt.h>
 #include <linux/slab.h>
 #include <linux/skbuff.h>
 
@@ -30,7 +29,6 @@
 #include <net/nfc/shdlc.h>
 
 #define SHDLC_LLC_HEAD_ROOM    2
-#define SHDLC_LLC_TAIL_ROOM    2
 
 #define SHDLC_MAX_WINDOW       4
 #define SHDLC_SREJ_SUPPORT     false
@@ -94,28 +92,13 @@ static struct sk_buff *nfc_shdlc_alloc_skb(struct nfc_shdlc *shdlc,
        struct sk_buff *skb;
 
        skb = alloc_skb(shdlc->client_headroom + SHDLC_LLC_HEAD_ROOM +
-                       shdlc->client_tailroom + SHDLC_LLC_TAIL_ROOM +
-                       payload_len, GFP_KERNEL);
+                       shdlc->client_tailroom + payload_len, GFP_KERNEL);
        if (skb)
                skb_reserve(skb, shdlc->client_headroom + SHDLC_LLC_HEAD_ROOM);
 
        return skb;
 }
 
-static void nfc_shdlc_add_len_crc(struct sk_buff *skb)
-{
-       u16 crc;
-       int len;
-
-       len = skb->len + 2;
-       *skb_push(skb, 1) = len;
-
-       crc = crc_ccitt(0xffff, skb->data, skb->len);
-       crc = ~crc;
-       *skb_put(skb, 1) = crc & 0xff;
-       *skb_put(skb, 1) = crc >> 8;
-}
-
 /* immediately sends an S frame. */
 static int nfc_shdlc_send_s_frame(struct nfc_shdlc *shdlc,
                                  enum sframe_type sframe_type, int nr)
@@ -131,8 +114,6 @@ static int nfc_shdlc_send_s_frame(struct nfc_shdlc *shdlc,
 
        *skb_push(skb, 1) = SHDLC_CONTROL_HEAD_S | (sframe_type << 3) | nr;
 
-       nfc_shdlc_add_len_crc(skb);
-
        r = shdlc->ops->xmit(shdlc, skb);
 
        kfree_skb(skb);
@@ -151,8 +132,6 @@ static int nfc_shdlc_send_u_frame(struct nfc_shdlc *shdlc,
 
        *skb_push(skb, 1) = SHDLC_CONTROL_HEAD_U | uframe_modifier;
 
-       nfc_shdlc_add_len_crc(skb);
-
        r = shdlc->ops->xmit(shdlc, skb);
 
        kfree_skb(skb);
@@ -509,8 +488,6 @@ static void nfc_shdlc_handle_send_queue(struct nfc_shdlc *shdlc)
                         shdlc->nr);
        /*      SHDLC_DUMP_SKB("shdlc frame written", skb); */
 
-               nfc_shdlc_add_len_crc(skb);
-
                r = shdlc->ops->xmit(shdlc, skb);
                if (r < 0) {
                        shdlc->hard_fault = r;
@@ -880,7 +857,7 @@ struct nfc_shdlc *nfc_shdlc_allocate(struct nfc_shdlc_ops *ops,
 
        shdlc->hdev = nfc_hci_allocate_device(&shdlc_ops, init_data, protocols,
                                              tx_headroom + SHDLC_LLC_HEAD_ROOM,
-                                             tx_tailroom + SHDLC_LLC_TAIL_ROOM,
+                                             tx_tailroom,
                                              max_link_payload);
        if (shdlc->hdev == NULL)
                goto err_allocdev;