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>

1 files changed, 2 insertions, 25 deletions

diff --git a/net/nfc/hci/shdlc.c b/net/nfc/hci/shdlc.c
index 824fb09384ed..ed8796b78f39 100644
--- 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;