GDB script for printing gpio configuration of a STM32F412 (requires SVDParser and a svd for the mcu)

gpio-getter.py

# First connect to the mcu via blackmagic probe or whatever
# usage (in gdb): source gpio-getter.py

from cmsis_svd.parser import SVDParser
import gdb

def read_memory(address, length):
    inferior = gdb.selected_inferior()
    return inferior.read_memory(address, length)

def print_pin_mode(mode):
    if mode == 0b00:
        return "Input"
    elif mode == 0b01:
        return "General purpose output"
    elif mode == 0b10:
        return "Alternate function"
    elif mode == 0b11:
        return "Analog"
    else:
        return "Invalid"
    
def print_pull_mode(mode):
    """
    00: No pull-up, pull-down
    01: Pull-up
    10: Pull-down
    11: Reserved
    """
    if mode == 0b00:
        return "No pull-up, pull-down"
    elif mode == 0b01:
        return "Pull-up"
    elif mode == 0b10:
        return "Pull-down"
    elif mode == 0b11:
        return "Reserved"
    else:
        return "Invalid"
    
def print_alternate_mode(mode):
    """
    AF0 (system)
AF1 (TIM1/TIM2)
AF2 (TIM3/5)
AF3 (TIM8/9)
AF4 (I2C1..3, I2CFMP1)
AF5 (SPI1/2/3/4)
AF6 (SPI2/3/4, DFSDM)
AF7 (SPI2, USART1..3)
AF8 (DFSDM, USART3/6, CAN1)
AF9 (I2C1..3, I2CFMP1, CAN1/2, TIM12..14, QUADSPI)
AF10 (DFSDM, FSMC, QUADSPI, OTG_FS)
AF11
AF12 (FMC, SDIO)
AF13
AF14
AF15 (EVENTOUT)
    """
    if mode == 0x01:
        return "TIM1/TIM2"
    elif mode == 0x02:
        return "TIM3/5"
    elif mode == 0x03:
        return "TIM8/9"
    elif mode == 0x04:
        return "(I2C1..3, I2CFMP1)"
    elif mode == 0x05:
        return "(SPI1/2/3/4)"
    elif mode == 0x06:
        return "(SPI2/3/4, DFSDM)"
    elif mode == 0x07:
        return "(SPI2, USART1..3)"
    elif mode == 0x08:
        return "(DFSDM, USART3/6, CAN1)"
    elif mode == 0x09:
        return "(I2C1..3, I2CFMP1, CAN1/2, TIM12..14, QUADSPI)"
    elif mode == 0x0A:
        return "(DFSDM, FSMC, QUADSPI, OTG_FS)"
    else:
        return str(mode)

def get_register_value(peripheral, register_name):
    peripheral_address = peripheral.base_address
    for register in peripheral.registers:
        if register.name == register_name:
            address = peripheral_address + register.address_offset
            value = None
            try:
                value = read_memory(address, register.size / 8).tobytes()
            except:
                print("Failed to read memory at 0x%08x for %s.%s" % (address, peripheral.name, register_name))
                return None
            value = int.from_bytes(value, byteorder='little')
            return value
    return None

parser = SVDParser.for_xml_file("STM32F412.svd")

gdb.execute("set mem inaccessible-by-default off")

limit_ports = ["GPIOA", "GPIOB", "GPIOC"]

for peripheral in parser.get_device().peripherals:
    if peripheral.name.startswith("GPIO"):
        if len(limit_ports) > 0 and peripheral.name not in limit_ports:
            continue
        letter = peripheral.name[-1]
        peripheral_address = peripheral.base_address
        for register in peripheral.registers:
            if register.name.startswith("MODER"):
                moder_address = peripheral_address + register.address_offset
                moder_value = None
                try:
                    
                    moder_value = read_memory(moder_address, register.size / 8).tobytes()
                except:
                    print("Failed to read memory at 0x%08x for %s.MODER" % (moder_address, peripheral.name))
                    continue
                print("%s.MODER @ 0x%08x:" % (peripheral.name, moder_address))
                moder_value = int.from_bytes(moder_value, byteorder='little')
                for pin in range(16):
                    pin_mode = (moder_value >> (pin*2)) & 0b11
                    extra = ""
                    if pin_mode == 0b00:
                        # find the PUPDR register
                        pupdr_value = get_register_value(peripheral, "PUPDR")
                        pull_mode = (pupdr_value >> (pin*2)) & 0b11
                        extra = "(%s)" % print_pull_mode(pull_mode)
                    if pin_mode == 0b10:
                        # Alternate function registers (low and high)
                        afrl_value = get_register_value(peripheral,  "AFRL" if pin < 8  else "AFRH")
                        # each pin is a nibble
                        nibble_offset = pin if pin < 8 else pin - 8
                        afrl_value = (afrl_value >> (nibble_offset*4)) & 0b1111
                        extra = "(%s)" % print_alternate_mode(afrl_value)
                        # print(afrl_value)
                    print("    P%s%d: %s %s" % (letter, pin, print_pin_mode(pin_mode), extra))