The curr_protocol field of nfc_digital_dev structure used to determine
if a target is currently active was set too soon, immediately when a
target is found. This is not good since there is no other way than
deactivate_target() to reset curr_protocol and if activate_target() is
not called, the target remains active and it's not possible to put the
device in poll mode anymore.
With this patch curr_protocol is set when nfc core activates a target,
puts a device up, or when an ATR_REQ is received in target mode.
Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
We do not add the newline to the pr_fmt macro, in order to give more
flexibility to the caller and to keep the logging style consistent with
the rest of the NFC and kernel code.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
They can be replaced by the standard pr_err and pr_debug one after
defining the right pr_fmt macro.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
This adds support for NFC-DEP target mode for NFC-A and NFC-F
technologies.
If the driver provides it, the stack uses an automatic mode for
technology detection and automatic anti-collision. Otherwise the stack
tries to use non-automatic synchronization and listens for SENS_REQ and
SENSF_REQ commands.
The detection, activation, and data exchange procedures work exactly
the same way as in initiator mode, as described in the previous
commits, except that the digital stack waits for commands and sends
responses back to the peer device.
Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
This adds support for NFC-DEP protocol in initiator mode for NFC-A and
NFC-F technologies.
When a target is detected, the process flow is as follow:
For NFC-A technology:
1 - The digital stack receives a SEL_RES as the reply of the SEL_REQ
command.
2 - If b7 of SEL_RES is set, the peer device is configure for NFC-DEP
protocol. NFC core is notified through nfc_targets_found().
Execution continues at step 4.
3 - Otherwise, it's a tag and the NFC core is notified. Detection
ends.
4 - The digital stacks sends an ATR_REQ command containing a randomly
generated NFCID3 and the general bytes obtained from the LLCP layer
of NFC core.
For NFC-F technology:
1 - The digital stack receives a SENSF_RES as the reply of the
SENSF_REQ command.
2 - If B1 and B2 of NFCID2 are 0x01 and 0xFE respectively, the peer
device is configured for NFC-DEP protocol. NFC core is notified
through nfc_targets_found(). Execution continues at step 4.
3 - Otherwise it's a type 3 tag. NFC core is notified. Detection
ends.
4 - The digital stacks sends an ATR_REQ command containing the NFC-F
NFCID2 as NFCID3 and the general bytes obtained from the LLCP layer
of NFC core.
For both technologies:
5 - The digital stacks receives the ATR_RES response containing the
NFCID3 and the general bytes of the peer device.
6 - The digital stack notifies NFC core that the DEP link is up through
nfc_dep_link_up().
7 - The NFC core performs data exchange through tm_transceive().
8 - The digital stack sends a DEP_REQ command containing an I PDU with
the data from NFC core.
9 - The digital stack receives a DEP_RES command
10 - If the DEP_RES response contains a supervisor PDU with timeout
extension request (RTOX) the digital stack sends a DEP_REQ
command containing a supervisor PDU acknowledging the RTOX
request. The execution continues at step 9.
11 - If the DEP_RES response contains an I PDU, the response data is
passed back to NFC core through the response callback. The
execution continues at step 8.
Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
This adds polling support for NFC-F technology at 212 kbits/s and 424
kbits/s. A user space application like neard can send type 3 tag
commands through the NFC core.
Process flow for NFC-F detection is as follow:
1 - The digital stack sends the SENSF_REQ command to the NFC device.
2 - A peer device replies with a SENSF_RES response.
3 - The digital stack notifies the NFC core of the presence of a
target in the operation field and passes the target NFCID2.
This also adds support for CRC calculation of type CRC-F. The CRC
calculation is handled by the digital stack if the NFC device doesn't
support it.
Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
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>
This implements the mechanism used to send commands to the driver in
initiator mode through in_send_cmd().
Commands are serialized and sent to the driver by using a work item
on the system workqueue. Responses are handled asynchronously by
another work item. Once the digital stack receives the response through
the command_complete callback, the next command is sent to the driver.
This also implements the polling mechanism. It's handled by a work item
cycling on all supported protocols. The start poll command for a given
protocol is sent to the driver using the mechanism described above.
The process continues until a peer is discovered or stop_poll is
called. This patch implements the poll function for NFC-A that sends a
SENS_REQ command and waits for the SENS_RES response.
Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
This is the initial commit of the NFC Digital Protocol stack
implementation.
It offers an interface for devices that don't have an embedded NFC
Digital protocol stack. The driver instantiates the digital stack by
calling nfc_digital_allocate_device(). Within the nfc_digital_ops
structure, the driver specifies a set of function pointers for driver
operations. These functions must be implemented by the driver and are:
in_configure_hw:
Hardware configuration for RF technology and communication framing in
initiator mode. This is a synchronous function.
in_send_cmd:
Initiator mode data exchange using RF technology and framing previously
set with in_configure_hw. The peer response is returned through
callback cb. If an io error occurs or the peer didn't reply within the
specified timeout (ms), the error code is passed back through the resp
pointer. This is an asynchronous function.
tg_configure_hw:
Hardware configuration for RF technology and communication framing in
target mode. This is a synchronous function.
tg_send_cmd:
Target mode data exchange using RF technology and framing previously
set with tg_configure_hw. The peer next command is returned through
callback cb. If an io error occurs or the peer didn't reply within the
specified timeout (ms), the error code is passed back through the resp
pointer. This is an asynchronous function.
tg_listen:
Put the device in listen mode waiting for data from the peer device.
This is an asynchronous function.
tg_listen_mdaa:
If supported, put the device in automatic listen mode with mode
detection and automatic anti-collision. In this mode, the device
automatically detects the RF technology and executes the
anti-collision detection using the command responses specified in
mdaa_params. The mdaa_params structure contains SENS_RES, NFCID1, and
SEL_RES for 106A RF tech. NFCID2 and system code (sc) for 212F and
424F. The driver returns the NFC-DEP ATR_REQ command through cb. The
digital stack deducts the RF tech by analyzing the SoD of the frame
containing the ATR_REQ command. This is an asynchronous function.
switch_rf:
Turns device radio on or off. The stack does not call explicitly
switch_rf to turn the radio on. A call to in|tg_configure_hw must turn
the device radio on.
abort_cmd:
Discard the last sent command.
Then the driver registers itself against the digital stack by using
nfc_digital_register_device() which in turn registers the digital stack
against the NFC core layer. The digital stack implements common NFC
operations like dev_up(), dev_down(), start_poll(), stop_poll(), etc.
This patch is only a skeleton and NFC operations are just stubs.
Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Thierry Escande
Samuel Ortiz