The NCI_STATIC_RF_CONN_ID logical connection is the most used
connection. Keeping it directly accessible in the nci_dev
structure will simplify and optimize the access.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
The NFCC sends an NCI_OP_RF_NFCEE_ACTION_NTF notification
to the host (DH) to let it know that for example an RF
transaction with a payment reader is done.
For now the notification handler is empty.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
NFC_EVT_TRANSACTION is sent through netlink in order for a
specific application running on a secure element to notify
userspace of an event. Typically the secure element application
counterpart on the host could interpret that event and act
upon it.
Forwarded information contains:
- SE host generating the event
- Application IDentifier doing the operation
- Applications parameters
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
According to the NCI specification, one can use HCI over NCI
to talk with specific NFCEE. The HCI network is viewed as one
logical NFCEE.
This is needed to support secure element running HCI only
firmwares embedded on an NCI capable chipset, like e.g. the
st21nfcb.
There is some duplication between this piece of code and the
HCI core code, but the latter would need to be abstracted even
more to be able to use NCI as a logical transport for HCP packets.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
In order to communicate with an NFCEE, we need to open a logical
connection to it, by sending the NCI_OP_CORE_CONN_CREATE_CMD
command to the NFCC. It's left up to the drivers to decide when
to close an already opened logical connection.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
NFCEEs can be enabled or disabled by sending the
NCI_OP_NFCEE_MODE_SET_CMD command to the NFCC. This patch
provides an API for drivers to enable and disable e.g. their
NCI discoveredd secure elements.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
NFCEEs (NFC Execution Environment) have to be explicitly
discovered by sending the NCI_OP_NFCEE_DISCOVER_CMD
command. The NFCC will respond to this command by telling
us how many NFCEEs are connected to it. Then the NFCC sends
a notification command for each and every NFCEE connected.
Here we implement support for sending
NCI_OP_NFCEE_DISCOVER_CMD command, receiving the response
and the potential notifications.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
The current NCI core only support the RF static connection.
For other NFC features such as Secure Element communication, we
may need to create logical connections to the NFCEE (Execution
Environment.
In order to track each logical connection ID dynamically, we add a
linked list of connection info pointers to the nci_dev structure.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
When a command is received, it is sometime needed to let the CLF driver do
some additional operations. (ex: count remaining pipe notification...)
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
As there can be several pipes connected to the same gate, we need
to know which pipe ID to use when sending an HCI response. A gate
ID is not enough.
Instead of changing the nfc_hci_send_response() API to something
not aligned with the rest of the HCI API, we call nfc_hci_hcp_message_tx
directly.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
In order to keep host source information on specific hci event (such as
evt_connectivity or evt_transaction) and because 2 pipes can be connected
to the same gate, it is necessary to add a table referencing every pipe
with a {gate, host} tuple.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Several pipes may point to the same CLF gate, so getting the gate ID
as an input is not enough.
For example dual secure element may have 2 pipes (1 for uicc and
1 for eSE) pointing to the connectivity gate.
As resolving gate and host IDs can be done from a pipe, we now pass
the pipe ID to the event received handler.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Some pipe are only created by other host (different than the
Terminal Host).
The pipe values will for example be notified by
NFC_HCI_ADM_NOTIFY_PIPE_CREATED.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
se_io allows to send apdu over the CLF to the embedded Secure Element.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Some NFC controller using NCI protocols may need a proprietary commands
flow to disable a secure element
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Some NFC controller using NCI protocols may need a proprietary commands
flow to enable a secure element
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Some NFC controller using NCI protocols may need a proprietary commands
flow to discover all available secure element
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
se_io allows to send apdu over the CLF to the embedded Secure Element.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
The Target responds to the ATR_REQ with the ATR_RES. Configure the General
Bytes in ATR_RES with the first three octets equal to the NFC Forum LLCP
magic number, followed by some LLC Parameters TLVs described in section
4.5 of [LLCP].
Signed-off-by: Julien Lefrique <lefrique@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Changes:
* Extract the Listen mode activation parameters from RF_INTF_ACTIVATED_NTF.
* Store the General Bytes of ATR_REQ.
* Signal that Target mode is activated in case of an activation in NFC-DEP.
* Update the NCI state accordingly.
* Use the various constants defined in nfc.h.
* Fix the ATR_REQ and ATR_RES maximum size. As per NCI 1.0 and NCI 1.1, the
Activation Parameters for both Poll and Listen mode contain all the bytes of
ATR_REQ/ATR_RES starting and including Byte 3 as defined in [DIGITAL].
In [DIGITAL], the maximum size of ATR_REQ/ATR_RES is 64 bytes and they are
numbered starting from Byte 1.
Signed-off-by: Julien Lefrique <lefrique@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Send LA_SEL_INFO and LF_PROTOCOL_TYPE with NFC-DEP protocol enabled.
Configure 212 Kbit/s and 412 Kbit/s bit rates for Listen F.
Signed-off-by: Julien Lefrique <lefrique@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
When an NFC-DEP Initiator times out when waiting for
a DEP_RES from the Target, its supposed to send an
ATN to the Target. The Target should respond to the
ATN with a similar ATN PDU and the Initiator can then
resend the last non-ATN PDU that it sent. No more
than 'N(retry,atn)' are to be send where
2 <= 'N(retry,atn)' <= 5. If the Initiator had just
sent a NACK PDU when the timeout occurred, it is to
continue sending NACKs until 'N(retry,nack)' NACKs
have been send. This is described in section
14.12.5.6 of the NFC-DEP Digital Protocol Spec.
The digital layer's NFC-DEP code doesn't implement
this so add that support.
The value chosen for 'N(retry,atn)' is 2.
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>
When an NFC-DEP Target receives a NACK PDU with
a PNI equal to 1 less than the current PNI, it
is supposed to re-send the last PDU. This is
implied in section 14.12.5.4 of the NFC Digital
Protocol Spec.
The digital layer's NFC-DEP code doesn't implement
Target-side NACK handing so add it. The last PDU
that was sent is saved in the 'nfc_digital_dev'
structure's 'saved_skb' member. The skb will have
an additional reference taken to ensure that the skb
isn't freed when the driver performs a kfree_skb()
on the skb. The length of the skb/PDU is also saved
so the length can be restored when re-sending the PDU
in the skb (the driver will perform an skb_pull() so
an skb_push() needs to be done to restore the skb's
data pointer/length).
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>
When an NFC-DEP Initiator receives a frame with
an incorrect CRC or with a parity error, and the
frame is at least 4 bytes long, its supposed to
send a NACK to the Target. The Initiator can
send up to 'N(retry,nack)' consecutive NACKs
where 2 <= 'N(retry,nack)' <= 5. When the limit
is exceeded, a PROTOCOL EXCEPTION is raised.
Any other type of transmission error is to be
ignored and the Initiator should continue
waiting for a new frame. This is described
in section 14.12.5.4 of the NFC Digital Protocol
Spec.
The digital layer's NFC-DEP code doesn't implement
any of this so add it. This support diverges from
the spec in two significant ways:
a) NACKs will be sent for ANY error reported by the
driver except a timeout. This is done because
there is currently no way for the digital layer
to distinguish a CRC or parity error from any
other type of error reported by the driver.
b) All other errors will cause a PROTOCOL EXCEPTION
even frames with CRC errors that are less than 4
bytes.
The value chosen for 'N(retry,nack)' is 2.
Targets do not send NACK PDUs.
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>
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>
The maximum payload for NFC-DEP exchanges (i.e., the
number of bytes between SoD and EoD) is negotiated
using the ATR_REQ, ATR_RES, and PSL_REQ commands.
The valid maximum lengths are 64, 128, 192, and 254
bytes.
Currently, NFC-DEP code assumes that both sides are
always using 254 byte maximums and ignores attempts
by the peer to change it. Instead, implement the
negotiation code, enforce the local maximum when
receiving data from the peer, and don't send payloads
that exceed the remote's maximum. The default local
maximum is 254 bytes.
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>
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>
In NFC Forum NCI specification, some RF Protocol values are
reserved for proprietary use (from 0x80 to 0xfe).
Some CLF vendor may need to use one value within this range
for specific technology.
Furthermore, some CLF may not becompliant with NFC Froum NCI
specification 2.0 and therefore will not support RF Protocol
value 0x06 for PROTOCOL_T5T as mention in a draft specification
and in a recent push.
Adding get_rf_protocol handle to the nci_ops structure will
help to set the correct technology to target.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
The digital layer of the NFC subsystem currently
supports a 'tg_listen_mdaa' driver hook that supports
devices that can do mode detection and automatic
anticollision. However, there are some devices that
can do mode detection but not automatic anitcollision
so add the 'tg_listen_md' hook to support those devices.
In order for the digital layer to get the RF technology
detected by the device from the driver, add the
'tg_get_rf_tech' hook. It is only valid to call this
hook immediately after a successful call to 'tg_listen_md'.
CC: 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>
Remove extra blank line that was inadvertently
added by a recent commit.
CC: 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>
stop_poll allows to stop CLF reader polling. Some other operations might be
necessary for some CLF to stop polling. For example in card mode.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Add new "NFC_DIGITAL_FRAMING_*" calls to the digital
layer so the driver can make the necessary adjustments
when performing anticollision while in target mode.
The driver must ensure that the effect of these calls
happens after the following response has been sent but
before reception of the next request begins.
Acked-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>
This allows for a more generic NFC sniffing by using SOCKPROTO_RAW
SOCK_RAW to read RAW NFC frames. This is for sniffing anything but LLCP
(HCI, NCI, etc...).
Signed-off-by: Hiren Tandel <hirent@marvell.com>
Signed-off-by: Rahul Tank <rahult@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Add RF tech and framing macros for the ISO/IEC 14443-B Protocol.
Cc: 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>
load_session allows a CLF to restore the gate <-> pipe table from some
proprietary location.
The main advantage to add this function is to reduce the memory wear by
running pipe creation (and storing) only once.
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
According to the latest draft specification from
the NFC-V committee, ISO/IEC 15693 tags will be
referred to as "Type 5" tags and not "Type V"
tags anymore. Make the code reflect the new
terminology.
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
This adds support for ATS request and response handling for type 4A tag
activation.
Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Add the header definitions required by upcoming
patches that add support for ISO/IEC 15693.
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
This API can be used by drivers to send their custom
configuration using SET_CONFIG NCI command to the device.
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Some drivers require special configuration while initializing.
This patch adds setup handler for this custom configuration.
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Several files refer to an old address for the Free Software Foundation
in the file header comment. Resolve by replacing the address with
the URL <http://www.gnu.org/licenses/> so that we do not have to keep
updating the header comments anytime the address changes.
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The NFC Forum NCI specification defines both a hardware and software
protocol when using a SPI physical transport to connect an NFC NCI
Chipset. The hardware requirement is that, after having raised the chip
select line, the SPI driver must wait for an INT line from the NFC
chipset to raise before it sends the data. The chip select must be
raised first though, because this is the signal that the NFC chipset
will detect to wake up and then raise its INT line. If the INT line
doesn't raise in a timely fashion, the SPI driver should abort
operation.
When data is transferred from Device host (DH) to NFC Controller (NFCC),
the signaling sequence is the following:
Data Transfer from DH to NFCC
• 1-Master asserts SPI_CSN
• 2-Slave asserts SPI_INT
• 3-Master sends NCI-over-SPI protocol header and payload data
• 4-Slave deasserts SPI_INT
• 5-Master deasserts SPI_CSN
When data must be transferred from NFCC to DH, things are a little bit
different.
Data Transfer from NFCC to DH
• 1-Slave asserts SPI_INT -> NFC chipset irq handler called -> process
reading from SPI
• 2-Master asserts SPI_CSN
• 3-Master send 2-octet NCI-over-SPI protocol header
• 4-Slave sends 2-octet NCI-over-SPI protocol payload length
• 5-Slave sends NCI-over-SPI protocol payload
• 6-Master deasserts SPI_CSN
In this case, SPI driver should function normally as it does today. Note
that the INT line can and will be lowered anytime between beginning of
step 3 and end of step 5. A low INT is therefore valid after chip select
has been raised.
This would be easily implemented in a single driver. Unfortunately, we
don't write the SPI driver and I had to imagine some workaround trick to
get the SPI and NFC drivers to work in a synchronized fashion. The trick
is the following:
- send an empty spi message: this will raise the chip select line, and
send nothing. We expect the /CS line will stay arisen because we asked
for it in the spi_transfer cs_change field
- wait for a completion, that will be completed by the NFC driver IRQ
handler when it knows we are in the process of sending data (NFC spec
says that we use SPI in a half duplex mode, so we are either sending or
receiving).
- when completed, proceed with the normal data send.
This has been tested and verified to work very consistently on a Nexus
10 (spi-s3c64xx driver). It may not work the same with other spi
drivers.
The previously defined nci_spi_ops{} whose intended purpose were to
address this problem are not used anymore and therefore totally removed.
The nci_spi_send() takes a new optional write_handshake_completion
completion pointer. If non NULL, the nci spi layer will run the above
trick when sending data to the NFC Chip. If NULL, the data is sent
normally all at once and it is then the NFC driver responsibility to
know what it's doing.
Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Previously, nci_spi_recv_frame() would directly transmit incoming frames
to the NCI Core. However, it turns out that some NFC NCI Chips will add
additional proprietary headers that must be handled/removed before NCI
Core gets a chance to handle the frame. With this modification, the chip
phy or driver are now responsible to transmit incoming frames to NCI
Core after proper treatment, and NCI SPI becomes a driver helper instead
of sitting between the NFC driver and NCI Core.
As a general rule in NFC, *_recv_frame() APIs are used to deliver an
incoming frame to an upper layer. To better suit the actual purpose of
nci_spi_recv_frame(), and go along with its nci_spi_send()
counterpart, the function is renamed to nci_spi_read()
The skb is returned as the function result
Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
In order to send and receive ISO7816 APDUs to and from NFC embedded
secure elements, we define a specific netlink command.
On a typical SE use case, host applications will send very few APDUs
(Less than 10) per transaction. This is why we decided to go for a
simple netlink API. Defining another NFC socket protocol for such low
traffic would have been overengineered.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
SENS_RES has no specific endiannes attached to it, the kernel ABI is the
following one: Byte 2 (As described by the NFC Forum Digital spec) is
the u16 most significant byte.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
This adds support for NFC-A technology at 106 kbits/s. The stack can
detect tags of type 1 and 2. There is no support for collision
detection. Tags can be read and written by using a user space
application or a daemon like neard.
The flow of polling operations for NFC-A detection is as follow:
1 - The digital stack sends the SENS_REQ command to the NFC device.
2 - The NFC device receives a SENS_RES response from a peer device and
passes it to the digital stack.
3 - If the SENS_RES response identifies a type 1 tag, detection ends.
NFC core is notified through nfc_targets_found().
4 - Otherwise, the digital stack sets the cascade level of NFCID1 to
CL1 and sends the SDD_REQ command.
5 - The digital stack selects SEL_CMD and SEL_PAR according to the
cascade level and sends the SDD_REQ command.
4 - The digital stack receives a SDD_RES response for the cascade level
passed in the SDD_REQ command.
5 - The digital stack analyses (part of) NFCID1 and verify BCC.
6 - The digital stack sends the SEL_REQ command with the NFCID1
received in the SDD_RES.
6 - The peer device replies with a SEL_RES response
7 - Detection ends if NFCID1 is complete. NFC core notified of new
target by nfc_targets_found().
8 - If NFCID1 is not complete, the cascade level is incremented (up
to and including CL3) and the execution continues at step 5 to
get the remaining bytes of NFCID1.
Once target detection is done, type 1 and 2 tag commands must be
handled by a user space application (i.e neard) through the NFC core.
Responses for type 1 tag are returned directly to user space via NFC
core.
Responses of type 2 commands are handled differently. The digital stack
doesn't analyse the type of commands sent through im_transceive() and
must differentiate valid responses from error ones.
The response process flow is as follow:
1 - If the response length is 16 bytes, it is a valid response of a
READ command. the packet is returned to the NFC core through the
callback passed to im_transceive(). Processing stops.
2 - If the response is 1 byte long and is a ACK byte (0x0A), it is a
valid response of a WRITE command for example. First packet byte
is set to 0 for no-error and passed back to the NFC core.
Processing stops.
3 - Any other response is treated as an error and -EIO error code is
returned to the NFC core through the response callback.
Moreover, since the driver can't differentiate success response from a
NACK response, the digital stack has to handle CRC calculation.
Thus, this patch also adds support for CRC calculation. If the driver
doesn't handle it, the digital stack will calculate CRC and will add it
to sent frames. CRC will also be checked and removed from received
frames. Pointers to the correct CRC calculation functions are stored in
the digital stack device structure when a target is detected. This
avoids the need to check the current target type for every call to
im_transceive() and for every response received from a peer device.
Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Christophe Ricard