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

This fix issue reported here:
https://lists.01.org/pipermail/linux-nfc/2014-September/002871.html

depmod: WARNING: found 6 modules in dependency cycles!
depmod: WARNING:
/lib/modules/3.17.0-rc3-00002-g7505ceaf/kernel/drivers/nfc/st21nfcb/st21nfcb.ko
in dependency cycle!
depmod: WARNING:
/lib/modules/3.17.0-rc3-00002-g7505ceaf/kernel/drivers/nfc/st21nfcb/ndlc.ko
in dependency cycle!
depmod: WARNING:
/lib/modules/3.17.0-rc3-00002-g7505ceaf/kernel/net/rfkill/rfkill.ko in
dependency cycle!
depmod: WARNING:
/lib/modules/3.17.0-rc3-00002-g7505ceaf/kernel/net/nfc/nfc.ko in
dependency cycle!
depmod: WARNING:
/lib/modules/3.17.0-rc3-00002-g7505ceaf/kernel/net/nfc/nci/nci.ko in
dependency cycle!
depmod: WARNING:
/lib/modules/3.17.0-rc3-00002-g7505ceaf/kernel/lib/crc-ccitt.ko in
dependency cycle!
./scripts/depmod.sh: line 57: 23387 Segmentation fault      (core
dumped) "$DEPMOD" "$@" "$KERNELRELEASE" $SYMBOL_PREFIX
make: *** [_modinst_post] Error 139
Reported-by: NDaniel Wagner <wagi@monom.org>
Signed-off-by: NChristophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

Add driver for STMicroelectronics ST21NFCB NFC controller.
ST21NFCB is using NCI protocol and a proprietary low level transport
protocol called NDLC used on top.

NDLC:
The protocol defines 2 types of frame:
- One type carrying NCI data (referred as DATAFRAME frames).
- One type carrying protocol information used for flow control and error
control mechanisms (referred as SUPERVISOR frames).

After each frame transmission to the NFC controller, the device host
SHALL waitfor  an ACK (SUPERVISOR frame) reception before sending a
new frame.
The NFC controller MAY send a frame at anytime to the device host.
The NFC controller MAY send a specific WAIT supervisor frame to indicate
to device host that a NCI data packet has been received but that it could
take significant time before the NFC controller sends an ACK and thus
allows next data reception.
Signed-off-by: NChristophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>