modem: cmux: Remove double buffering from frame parsing#105370
Merged
MaureenHelm merged 2 commits intozephyrproject-rtos:mainfrom Mar 17, 2026
Merged
modem: cmux: Remove double buffering from frame parsing#105370MaureenHelm merged 2 commits intozephyrproject-rtos:mainfrom
MaureenHelm merged 2 commits intozephyrproject-rtos:mainfrom
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Remove double buffering that was using a separate work_buffer. Receive and parse frames directly into receive_buffer instead. This saves MODEM_CMUX_WORK_BUFFER_SIZE of RAM and avoids one copy from work_buffer to receive_buffer. Driver already asserts if the receive buffer does not fit maximum frame, so it should be properly sized. Signed-off-by: Seppo Takalo <seppo.takalo@nordicsemi.no>
Check for: * valid frame type * valid address (range 0..63) * command decoding length. Signed-off-by: Seppo Takalo <seppo.takalo@nordicsemi.no>
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rerickson1
approved these changes
Mar 12, 2026
bjarki-andreasen
approved these changes
Mar 13, 2026
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Remove double buffering that was using a separate
cmux->work_bufferto fetch data frommodem_pipe. The packet content was then copied into
cmux->receive_bufferbefore being pushed into the DLC pipe, which have their own buffer.So this double-buffering is redudant.
Instead, receive and parse frames directly into receive_buffer.
This saves MODEM_CMUX_WORK_BUFFER_SIZE of RAM and avoids
one copy from work_buffer to receive_buffer.
Driver already asserts if the receive buffer does not fit
maximum frame, so it should be properly sized.
Minor changes:
Add few checks into CMUX frame parsing.
These are mostly a result of fuzz testing the parser. Not issues seen in real life.