NFC: digital: Add Target-mode NFC-DEP DID Support

When in Target mode, the Initiator specifies whether
subsequent DEP_REQ and DEP_RES frames will include
a DID byte by the value passed in the ATR_REQ.  If
the DID value in the ATR_REQ is '0' then no DID
byte will be included.  If the DID value is between
'1' and '14' then a DID byte containing the same
value must be included in subsequent DEP_REQ and
DEP_RES frames.  Any other DID value is invalid.
This is specified in sections 14.8.1.2 and 14.8.2.2
of the NFC Digital Protocol Spec.

Checking the DID value (if it should be there at all),
is not currently supported by the digital layer's
NFC-DEP code.  Add this support by remembering the
DID value in the ATR_REQ, checking the DID value of
received DEP_REQ frames (if it should be there at all),
and including the remembered DID value in DEP_RES
frames when appropriate.

Reviewed-by: Thierry Escande <thierry.escande@linux.intel.com>
Tested-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/net/nfc/digital.h b/include/net/nfc/digital.h
index d9a5cf7..80c6183 100644
--- a/include/net/nfc/digital.h
+++ b/include/net/nfc/digital.h
@@ -225,6 +225,7 @@ struct nfc_digital_dev {
 	u8 curr_protocol;
 	u8 curr_rf_tech;
 	u8 curr_nfc_dep_pni;
+	u8 did;
 
 	u16 target_fsc;