NFC: digital: Add NFC-DEP Send Chaining Support

When the NFC-DEP code is given a packet to send
that is larger than the peer's maximum payload,
its supposed to set the 'MI' bit in the 'I' PDU's
Protocol Frame Byte (PFB).  Setting this bit
indicates that NFC-DEP chaining is to occur.

When NFC-DEP chaining is progress, sender 'I' PDUs
are acknowledged with 'ACK' PDUs until the last 'I'
PDU in the chain (which has the 'MI' bit cleared)
is responded to with a normal 'I' PDU.  This can
occur while in Initiator mode or in Target mode.

Sender NFC-DEP chaining is currently not implemented
in the digital layer so add that support.  Unfortunately,
since sending a frame may require writing the CRC to the
end of the data, the relevant data part of the original
skb must be copied for each intermediate frame.

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>
2 files changed