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authorWaldemar Rymarkiewicz <waldemar.rymarkiewicz@tieto.com>2012-09-07 11:08:29 +0200
committerSamuel Ortiz <sameo@linux.intel.com>2012-09-25 00:17:24 +0200
commitade672082dd35aaaf7c8630d16c9f795c30459c4 (patch)
treebd0c438012bbf4006f63b3f13faddf0d5803d357 /drivers/nfc
parent52da2449e10039d3bb04c598d24cb1a34530b716 (diff)
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>
Diffstat (limited to 'drivers/nfc')
-rw-r--r--drivers/nfc/pn544_hci.c32
1 files changed, 30 insertions, 2 deletions
diff --git a/drivers/nfc/pn544_hci.c b/drivers/nfc/pn544_hci.c
index 9458d53cdb5..d90aecfce73 100644
--- 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) {