Make read()/write() hide all the details of handling the USB Mode
Protocol.
Unfortunately this also introduces 4 bytes to the .bss segment which
was removed because of lack of FW_RAM, originally just 1 kB. We add
back support in start.S and the linker script.
Throwing away mode and length from incoming data. Adding mode and
length to outgoing data.
Splitting responses into frames small enough for the USB<->UART
transceiver to handle.
Add clang-tidy and splint static analytics check. For now, we use only
the cert-* warnings on clang-tidy and run splint with a lot of flags
to allow more things.
Changes to silence these analytics:
- Stop returning stuff from our debug print functions. We don't check
them anyway and we don't have any way of detecting transmission
failure.
- Declare more things static that isn't used outside of a file.
- Change types to be more consistent, typically to size_t or
something or to uint32_t.
- We always assert on allowed commands in a state.
- We don't allow FW_CMD_LOAD_APP to be used twice.
- Enter fail state on read buffer overrun, header endpoint not for us,
header parse error, and unknown firmware command.
Signed-off-by: Daniel Lublin <daniel@lublin.se>
We introduce an explicit state machine (see README).
With the new states we:
- combine setting size and USS to a single command.
- start the device app immediatiely when having receceived the last
data chunk and returning the digest.
- Loop forever and wait for the stick to be removed if we end up in
unknown state.
Signed-off-by: Michael Cardell Widerkrantz <mc@tillitis.se>
