NFC Digital: Add NFC-F technology support

This adds polling support for NFC-F technology at 212 kbits/s and 424
kbits/s. A user space application like neard can send type 3 tag
commands through the NFC core.

Process flow for NFC-F detection is as follow:

1 - The digital stack sends the SENSF_REQ command to the NFC device.
2 - A peer device replies with a SENSF_RES response.
3   - The digital stack notifies the NFC core of the presence of a
      target in the operation field and passes the target NFCID2.

This also adds support for CRC calculation of type CRC-F. The CRC
calculation is handled by the digital stack if the NFC device doesn't
support it.

Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/net/nfc/digital.h b/net/nfc/digital.h
index fb5324b792de..85bc74c988f8 100644
--- a/net/nfc/digital.h
+++ b/net/nfc/digital.h
@@ -20,6 +20,7 @@
 #include <net/nfc/digital.h>
 
 #include <linux/crc-ccitt.h>
+#include <linux/crc-itu-t.h>
 
 #define PR_DBG(fmt, ...)  pr_debug("%s: " fmt "\n", __func__, ##__VA_ARGS__)
 #define PR_ERR(fmt, ...)  pr_err("%s: " fmt "\n", __func__, ##__VA_ARGS__)
@@ -64,6 +65,7 @@ static inline int digital_in_send_cmd(struct nfc_digital_dev *ddev,
 void digital_poll_next_tech(struct nfc_digital_dev *ddev);
 
 int digital_in_send_sens_req(struct nfc_digital_dev *ddev, u8 rf_tech);
+int digital_in_send_sensf_req(struct nfc_digital_dev *ddev, u8 rf_tech);
 
 int digital_target_found(struct nfc_digital_dev *ddev,
                          struct nfc_target *target, u8 protocol);
@@ -74,6 +76,7 @@ typedef u16 (*crc_func_t)(u16, const u8 *, size_t);
 
 #define CRC_A_INIT 0x6363
 #define CRC_B_INIT 0xFFFF
+#define CRC_F_INIT 0x0000
 
 void digital_skb_add_crc(struct sk_buff *skb, crc_func_t crc_func, u16 init,
                          u8 bitwise_inv, u8 msb_first);
@@ -88,6 +91,11 @@ static inline void digital_skb_add_crc_b(struct sk_buff *skb)
         digital_skb_add_crc(skb, crc_ccitt, CRC_B_INIT, 1, 0);
 }
 
+static inline void digital_skb_add_crc_f(struct sk_buff *skb)
+{
+        digital_skb_add_crc(skb, crc_itu_t, CRC_F_INIT, 0, 1);
+}
+
 static inline void digital_skb_add_crc_none(struct sk_buff *skb)
 {
         return;
@@ -106,6 +114,11 @@ static inline int digital_skb_check_crc_b(struct sk_buff *skb)
         return digital_skb_check_crc(skb, crc_ccitt, CRC_B_INIT, 1, 0);
 }
 
+static inline int digital_skb_check_crc_f(struct sk_buff *skb)
+{
+        return digital_skb_check_crc(skb, crc_itu_t, CRC_F_INIT, 0, 1);
+}
+
 static inline int digital_skb_check_crc_none(struct sk_buff *skb)
 {
         return 0;