Add Asynchronous UART implementation, which does not drop data
when automatic hardware-flow-control is set in the device tree.
With automatic hardware flow control, the CTS pin will be
automatically deactivated when there are no more asynchronous
UART RX buffers available. After buffer space becomes available,
and UART RX is restarted, the CTS pin will be activated.
Signed-off-by: Markus Lassila <markus.lassila@nordicsemi.no>
If we end up writing zero bytes to cmux output, we can return
zero instead of -ENOMEM as it would break various modules when
using small buffers. For example modem_chat.c does not tolerate
-ENOMEM but handles zero OK.
Signed-off-by: Seppo Takalo <seppo.takalo@nordicsemi.no>
Allow configuring MTU for CMUX.
Some AT manual and specification define this as a
frame size. Linux ldattach default to 127 bytes,
3GPP TS 27.010 defaults to 31.
We should limit our CMUX frames to a size that
remote end is capable of handling.
Linux silently drops oversized frames.
Also, remove MODEM_CELLULAR_CMUX_MAX_FRAME_SIZE as
this was only limiting a buffer sizes, and resulted
CMUX frames to be capped to same value.
Use MODEM_CMUX_WORK_BUFFER_SIZE and MODEM_CMUX_MTU instead.
Also rename CONFIG_MODEM_CELLULAR_CHAT_BUFFER_SIZES to
CONFIG_MODEM_CELLULAR_CHAT_BUFFER_SIZE as it is now
only used as a Chat module. DLCI pipes use
CONFIG_MODEM_CMUX_WORK_BUFFER_SIZE.
Signed-off-by: Seppo Takalo <seppo.takalo@nordicsemi.no>
To improve performance in FCS calculation, this commit replaces
the usage of the generic `crc8` function with the specific `crc8_rohc`
function in `modem_cmux.c`.
The `crc8_rohc` function utilizes a small table approach, enhancing
the efficiency of CRC-8/ROHC variant calculations while optimizing
memory usage.
Signed-off-by: Pisit Sawangvonganan <pisit@ndrsolution.com>
Added `static const` to various `struct modem_pipe_api` and
`frame` in `modem_cmux_connect_handler` to make these structures
immutable and reduce RAM usage.
Corrected a typo, changing "consequtive" to "consecutive".
Signed-off-by: Pisit Sawangvonganan <pisit@ndrsolution.com>
The cmux module does not properly cancel all work when it is
released from its modem pipe. Releasing CMUX must cancel all
work as the pipe is no longer available, as it is set to NULL.
If work remains which tries to transmit something to the now
released pipe, a NULL dereference occurs.
This exact issue occurs if a DLCI channel is trying to open
after the modem pipe has been released, as the CMUX component
will send an open request at a fixed interval.
The expected behavior is for the open request to be cancelled,
and further open requests to be prevented until cmux is again
attached to a pipe.
Lastly, added a check to ensure that the pipe is indeed released
when calling attach, to ensure all work is indeed stopped before
modifying the pipe and buffers.
Signed-off-by: Bjarki Arge Andreasen <bjarki@arge-andreasen.me>
A Kconfig item is added and the buffer
is embedded into the modem_cmux struct.
The default value is increased from 16 to 64 bytes in
an effort to reduce the number of modem_pipe_receive() calls.
CONFIG_MODEM_CHAT_LOG_BUFFER is renamed
to CONFIG_MODEM_CHAT_LOG_BUFFER_SIZE for consistency.
Signed-off-by: Tomi Fontanilles <tomi.fontanilles@nordicsemi.no>
- Add the frame data length to the frame header log.
- Log the dropped frames as well.
Signed-off-by: Tomi Fontanilles <tomi.fontanilles@nordicsemi.no>
This allows to properly drop single CMUX frames that are
too big to fit in the receive buffer, keeping track of
where they end so that following frames are received
correctly regardless of the data contents.
Signed-off-by: Tomi Fontanilles <tomi.fontanilles@nordicsemi.no>
Changes include:
- Improving handling of frames for unconfigured DLCIs.
- Adding logs and outputting error codes in failure cases.
- Adding warnings to not reuse buffers.
- Fixing comments.
Signed-off-by: Tomi Fontanilles <tomi.fontanilles@nordicsemi.no>
Use transmit idle event to synchronize with data transmitted
through DLCI pipes to test TRANSMIT_IDLE implementation.
Signed-off-by: Bjarki Arge Andreasen <bjarki@arge-andreasen.me>
Implement transmit idle event both for transmitting data to the
bus, and for the individual DLCI channels.
Signed-off-by: Bjarki Arge Andreasen <bjarki@arge-andreasen.me>
This optimization aggregates frame headers before adding to the ring buffer
and computes the FCS of the frame header in one operation.
This approach improves execution efficiency and reduces memory footprint.
This code adjustment aligns with the changes proposed in https://github.com/zephyrproject-rtos/zephyr/pull/67062.
Signed-off-by: Pisit Sawangvonganan <pisit@ndrsolution.com>
Some modems don't start sending resync flags as described in
3G TS 27.010 V2.0.0 5.2.5, which results in the CMUX being
stuck in resync mode for said modems.
This patch simplifies the resync mechanism to simply drop
invalid frames, and wait for atleast two consequtive frame
flags (stop+start).
Signed-off-by: Bjarki Arge Andreasen <bjarki@arge-andreasen.me>
DLCI receive buffer may overrun if data is not processed fast
enough. This error was not reported before this patch, resulting
in unexplained missing bytes.
Signed-off-by: Bjarki Arge Andreasen <bjarki@arge-andreasen.me>
The CMUX resync mechanism can get stuck between states
MODEM_CMUX_RECEIVE_STATE_RESYNC_0 and
MODEM_CMUX_RECEIVE_STATE_RESYNC_1 if the resync flags, which are
sent only once in state MODEM_CMUX_RECEIVE_STATE_SOF, are not
responded to, or the response is lost.
This patch ensures resync flags are sent from states
MODEM_CMUX_RECEIVE_STATE_SOF, MODEM_CMUX_RECEIVE_STATE_RESYNC_1
and MODEM_CMUX_RECEIVE_STATE_RESYNC_2 if its determined that the
resync flags are not being responded to.
Signed-off-by: Bjarki Arge Andreasen <bjarki@arge-andreasen.me>
In cases where the data is bigger than 127 bytes,
the first bit of the second byte of the data length field
used to always be set.
This is wrong as according to the 3GPP 27.010 spec
only the first bit of the first byte is the EA bit;
all the others denote the data length.
Signed-off-by: Tomi Fontanilles <tomi.fontanilles@nordicsemi.no>
Added missing command and message handling for use existing
modem cmux for DCE role.
DCE CMUX connection can be now initialized from DTE side.
Signed-off-by: Juha Heiskanen <juha.heiskanen@nordicsemi.no>
Possible NULL pointer dereferences where discovered by static
code analysis, they are addressed in this commit.
Signed-off-by: Bjarki Arge Andreasen <bjarki@arge-andreasen.me>
This commit reuses the string "Unknown %s frame type" for two
log messages, as suggested by ycsin.
Signed-off-by: Bjarki Arge Andreasen <bjarkix123@gmail.com>
This commit resets the state of the CMUX receive state
machine when the CMUX instance is attached to a pipe.
Signed-off-by: Bjarki Arge Andreasen <bjarkix123@gmail.com>
This commit adds logging for CMUX frames and commands and
their data, for both transmit and receive. It also removes
the superseded LOG_DBG() lines like "Received frame".
Signed-off-by: Bjarki Arge Andreasen <bjarkix123@gmail.com>
This commit resets the receive ring buffer for each DLCI
pipe when they are opened. They may have old data stored
from last time they where opened.
Signed-off-by: Bjarki Arge Andreasen <bjarkix123@gmail.com>
This commit adds a check to the async connect and disconnect
functions to validate the CMUX is not already connected
or disconnected respectively. This was already part of the
sync connect and disconnect functions, so the sync functions
now simply wrap the async functions to avoid duplicate code.
Signed-off-by: Bjarki Arge Andreasen <bjarkix123@gmail.com>
This commit increases the buffer used for commands
in the control channel within an instance of the
modem_cmux module. The buffer was not large enough to
store an MSC command if the optional break signals
where included. This commit fixes the issue and
updates the test suite to use the max size MSC message.
Signed-off-by: Bjarki Arge Andreasen <baa@trackunit.com>
This commit sets the C/R (command/response) bit when UIH
CMUX frames are sent from the modem_cmux module. This bit
is ignored by some modems like the Quectel BG95, as there
is no defined response to this specific CMUX frame type.
However, other modems, like the TELIT ME910, require the
bit to be set (command). If the bit is not set, the modem
will simply ignore the frame completely.
Signed-off-by: Bjarki Arge Andreasen <bjarkix123@gmail.com>
This PR adds the following modem modules to the subsys/modem
folder:
- chat: Light implementation of the Linux chat program, used to
send and receive text based commands statically created
scripts.
- cmux: Implementation of the CMUX protocol
- pipe: Thread-safe async data-in/data-out binding layer between
modem modules.
- ppp: Implementation of the PPP protocol, binding the Zephyr PPP
L2 stack with the data-in/data-out pipe.
These modules use the abstract pipes to communicate between each
other. To bind them with the hardware, the following backends
are provided:
- TTY: modem pipe <-> POSIX TTY file
- UART: modem pipe <-> UART, async and ISR APIs supported
The backends are used to abstract away the physical layer, UART,
TTY, IPC, I2C, SPI etc, to a modem modules friendly pipe.
Signed-off-by: Bjarki Arge Andreasen <baa@trackunit.com>
Markus Lassila
Seppo Takalo
Henrik Skreslet
Pisit Sawangvonganan
Bjarki Arge Andreasen
Tomi Fontanilles
Juha Heiskanen
Bjarki Arge Andreasen
Bjarki Arge Andreasen
Fabio Baltieri