linux-imx

NFC: st21nfcb: Add support for secure element

The st21nfcb chipset has 3 SWP (Single Wire Protocol) lines and
supports up to 3 secure elements (UICC/eSE and µSD in the future).

Some st21nfcb firmware does not support the nci command
nci_nfcee_mode_set(NCI_NFCEE_DISABLE). For this reason, we assume
2 secures elements are always present (UICC and eSE).
They will be added to the SE list once successfully activated and
they will be available only after running through enable_se
handler or when the poll in listen mode is started.

During initialization, the white_list will be always set assuming
both UICC & eSE are present.

On eSE activation, the ATR bytes are fetched to build the command
exchange timeout.

The se_io hook will allow to transfer data over SWP. 2 kind of
events may appear data is sent over:
- ST21NFCB_EVT_TRANSMIT_DATA when receiving an apdu answer
- ST21NFCB_EVT_WTX_REQUEST when the secure element needs more time
  than expected to process a command. If this timeout expires, we
  send a software reset, and then a hardware one if it still fails.

Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>