MarlinFirmware/buildroot/share/PlatformIO/scripts/stm32_serialbuffer.py

#
# stm32_serialbuffer.py
#
Import("env")

# Marlin uses the `RX_BUFFER_SIZE` \ `TX_BUFFER_SIZE` options to
# configure buffer sizes for receiving \ transmitting serial data.
# Stm32duino uses another set of defines for the same purpose, so this
# script gets the values from the configuration and uses them to define
# `SERIAL_RX_BUFFER_SIZE` and `SERIAL_TX_BUFFER_SIZE` as global build
# flags so they are available for use by the platform.
#
# The script will set the value as the default one (64 bytes)
# or the user-configured one, whichever is higher.
#
# Marlin's default buffer sizes are 128 for RX and 32 for TX.
# The highest value is taken (128/64).
#
# If MF_*_BUFFER_SIZE, SERIAL_*_BUFFER_SIZE, USART_*_BUF_SIZE, are
# defined, the first of these values will be used as the minimum.
build_flags = env.ParseFlags(env.get('BUILD_FLAGS'))["CPPDEFINES"]
mf = env["MARLIN_FEATURES"]

# Get a build flag's value or None
def getBuildFlagValue(name):
	for flag in build_flags:
		if isinstance(flag, list) and flag[0] == name:
			return flag[1]

	return None

# Get an overriding buffer size for RX or TX from the build flags
def getInternalSize(side):
	return	getBuildFlagValue(f"MF_{side}_BUFFER_SIZE") or \
			getBuildFlagValue(f"SERIAL_{side}_BUFFER_SIZE") or \
			getBuildFlagValue(f"USART_{side}_BUF_SIZE")

# Get the largest defined buffer size for RX or TX
def getBufferSize(side, default):
	# Get a build flag value or fall back to the given default
	internal = int(getInternalSize(side) or default)
	flag = side + "_BUFFER_SIZE"
	# Return the largest value
	return max(int(mf[flag]), internal) if flag in mf else internal

# Add a build flag if it's not already defined
def tryAddFlag(name, value):
	if getBuildFlagValue(name) is None:
		env.Append(BUILD_FLAGS=[f"-D{name}={value}"])

# Get the largest defined buffer sizes for RX or TX, using defaults for undefined
rxBuf = getBufferSize("RX", 128)
txBuf = getBufferSize("TX",  64)

# Provide serial buffer sizes to the stm32duino platform
tryAddFlag("SERIAL_RX_BUFFER_SIZE", rxBuf)
tryAddFlag("SERIAL_TX_BUFFER_SIZE", txBuf)
tryAddFlag("USART_RX_BUF_SIZE", rxBuf)
tryAddFlag("USART_TX_BUF_SIZE", txBuf)