debug_probe.py

# pyOCD debugger
# Copyright (c) 2018-2020 Arm Limited
# Copyright (c) 2021-2023 Chris Reed
# SPDX-License-Identifier: Apache-2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from __future__ import annotations

from enum import (Enum, IntFlag)
import threading
from typing import (Callable, Collection, Optional, overload, Sequence, Set, TYPE_CHECKING, Tuple, Union)
from typing_extensions import Literal

if TYPE_CHECKING:
    from ..core.session import Session
    from ..core.memory_interface import MemoryInterface
    from ..board.board import Board
    from ..board.board_ids import BoardInfo
    from ..coresight.ap import APAddressBase

class DebugProbe:
    """@brief Abstract debug probe class.

    Subclasses of this abstract class are drivers for different debug probe interfaces, either hardware such as a
    USB based probe, or software such as connecting with a simulator.

    The constructor is private. To create an instance, use either of get_all_connected_probes() or get_probe_with_id().
    Normally, the @ref pyocd.probe.aggregator.DebugProbeAggregator "DebugProbeAggregator" class is used instead of
    directly calling methods on a specific probe class.

    Use an instance as follows:

    1. Call open().
    2. Optionally inspect the `supported_wire_protocols` property and select a protocol to use.
    3. Call connect(), passing the chosen wire protocol.
    4. Use by instance by calling other methods.
    5. Call disconnect().
    6. Call close().

    Most methods are required to be overridden by a subclass, with a few exceptions.

    These methods are completely optional:

    - create_associated_board()
    - flush()
    - get_memory_interface_for_ap()

    These methods must be implemented depending on the probe capabilities, as returned from the `capabilities` property.

    - swj_sequence(): Capability.SWJ_SEQUENCE; if not provided it is assumed the probe automatically enables SWD or JTAG
        on the target based on the protocol passed into connect().
    - swd_sequence(): Capability.SWD_SEQUENCE
    - jtag_sequence(): Capability.JTAG_SEQUENCE
    - swo_*(): Capability.SWO
    - get_accessible_pins(): Capability.PIN_ACCESS
    - read_pins(): Capability.PIN_ACCESS
    - write_pins(): Capability.PIN_ACCESS
    """

    class Protocol(Enum):
        """@brief Debug wire protocols."""
        DEFAULT = 0
        SWD = 1
        JTAG = 2

    class PinGroup(Enum):
        """@brief Available pin groups for read/write pins APIs."""
        PROTOCOL_PINS = 0
        GPIO_PINS = 1

    class ProtocolPin(IntFlag):
        """@brief Pin mask constants for SWD/JTAG protocol pins."""
        SWCLK_TCK = 1 << 0
        SWDIO_TMS = 1 << 1
        TDI = 1 << 2
        TDO = 1 << 3
        nRESET = 1 << 4
        nTRST = 1 << 5
        ALL_PINS = SWCLK_TCK | SWDIO_TMS | TDI | TDO | nRESET | nTRST

    ## Map from wire protocol setting name to debug probe constant.
    PROTOCOL_NAME_MAP = {
            'swd': Protocol.SWD,
            'jtag': Protocol.JTAG,
            'default': Protocol.DEFAULT,
        }

    class Capability(Enum):
        """@brief Probe capabilities."""
        ## @brief Whether the probe supports the swj_sequence() API.
        #
        # If this property is True, then the swj_sequence() method is used to move between protocols.
        # If False, it is assumed the probe firmware automatically manages the protocol switch.
        SWJ_SEQUENCE = 0

        ## @brief Whether the probe supports receiving SWO data.
        SWO = 1

        ## @brief Whether the probe can access banked DP registers.
        #
        # Currently only used to verify that the probe supports banked DP registers when the #MANAGED_DPBANKSEL
        # capability is present.
        BANKED_DP_REGISTERS = 2

        ## @brief Whether the probe can access APv2 registers.
        #
        # This capability is currently only used to verify that a probe with the #MANAGED_AP_SELECTION capability
        # can support the wider AP addresses used in version 2 APs. For probes without #MANAGED_AP_SELECTION,
        # DP_SELECT is written directly by the DAP layer when selecting an AP.
        APv2_ADDRESSES = 3

        ## @brief Whether the probe automatically handles AP selection in the DP.
        #
        # If this capability is not present, the DebugPort object will perform the AP selection
        # by DP register writes.
        MANAGED_AP_SELECTION = 4

        ## @brief whether the probe automatically handles access of banked DAP registers.
        MANAGED_DPBANKSEL = 5

        ## @brief Whether the probe supports the swd_sequence() API.
        SWD_SEQUENCE = 6

        ## @brief Whether the probe supports the jtag_sequence() API.
        JTAG_SEQUENCE = 7

        ## @brief Pin access via the read_pins()/write_pins() APIs.
        PIN_ACCESS = 8

    @classmethod
    def get_all_connected_probes(
                cls,
                unique_id: Optional[str] = None,
                is_explicit: bool = False
            ) -> Sequence[DebugProbe]:
        """@brief Returns a list of DebugProbe instances.

        To filter the list of returned probes, the `unique_id` parameter may be set to a string with a full or
        partial unique ID (canonically the serial number). Alternatively, the probe class may simply return all
        available probes and let the caller handle filtering.

        @param cls The class instance.
        @param unique_id String. Optional partial unique ID value used to filter available probes. May be used by the
            probe to optimize retrieving the probe list; there is no requirement to filter the results.
        @param is_explicit Boolean. Whether the probe type was explicitly specified in the unique ID. This
            can be used, for instance, to specially interpret the unique ID as an IP address or
            domain name when the probe class was specifically requested but not for general lists
            of available probes.
        @return List of DebugProbe instances.
        """
        raise NotImplementedError()

    @classmethod
    def get_probe_with_id(cls, unique_id: str, is_explicit: bool = False) -> Optional[DebugProbe]:
        """@brief Returns a DebugProbe instance for a probe with the given unique ID.

        If no probe is connected with a fully matching unique ID, then None will be returned.

        @param cls The class instance.
        @param unique_id Unique ID string to match against probes' full unique ID. No partial matches are allowed.
        @param is_explicit Boolean. Whether the probe type was explicitly specified in the unique ID.
        @return DebugProbe instance, or None
        """
        raise NotImplementedError()

    def __init__(self) -> None:
        """@brief Constructor."""
        self._session: Optional[Session] = None
        self._lock = threading.RLock()

    @property
    def session(self) -> Optional[Session]:
        """@brief Session associated with this probe."""
        return self._session

    @session.setter
    def session(self, the_session: Session) -> None:
        self._session = the_session

    @property
    def description(self) -> str:
        """@brief Combined description of the debug probe and/or associated board."""
        return self.vendor_name + " " + self.product_name

    @property
    def vendor_name(self) -> str:
        """@brief Name of the debug probe's manufacturer."""
        raise NotImplementedError()

    @property
    def product_name(self) -> str:
        """@brief Name of the debug probe."""
        raise NotImplementedError()

    @property
    def supported_wire_protocols(self) -> Collection[Protocol]:
        """@brief List of DebugProbe.Protocol supported by the probe.

        Only one of the values returned from this property may be passed to connect().
        """
        raise NotImplementedError()

    @property
    def unique_id(self) -> str:
        """@brief The unique ID of this device.

        This property will be valid before open() is called. This value can be passed to
        get_probe_with_id().
        """
        raise NotImplementedError()

    @property
    def wire_protocol(self) -> Optional[Protocol]:
        """@brief Currently selected wire protocol.

        If the probe is not open and connected, i.e., open() and connect() have not been called,
        then this property will be None. If a value other than None is returned, then the probe
        has been connected successfully.
        """
        raise NotImplementedError()

    @property
    def is_open(self) -> bool:
        """@brief Whether the probe is currently open.

        To open the probe, call the open() method.
        """
        raise NotImplementedError()

    @property
    def capabilities(self) -> Set[Capability]:
        """@brief A set of DebugProbe.Capability enums indicating the probe's features.

        This value should not be trusted until after the probe is opened.
        """
        raise NotImplementedError()

    @property
    def associated_board_info(self) -> Optional[BoardInfo]:
        """@brief Info about the board associated with this probe, if known."""
        return None

    def create_associated_board(self) -> Optional[Board]:
        """@brief Create a board instance representing the board of which the probe is a component.

        If the probe is part of a board, then this method will create a Board instance that
        represents the associated board. Usually, for an on-board debug probe, this would be the
        Board that the probe physically is part of, and will also set the target type. If the probe
        does not have an associated board, then this method returns None.

        @param self
        """
        return None

    def get_accessible_pins(self, group: PinGroup) -> Tuple[int, int]:
        """@brief Return masks of pins accessible via the .read_pins()/.write_pins() methods.

        This method is only expected to be implemented if Capability.PIN_ACCESS is present.

        @return Tuple of pin masks for (0) readable, (1) writable pins. See DebugProbe.Pin for mask
        values for those pins that have constants.
        """
        raise NotImplementedError()

    def open(self) -> None:
        """@brief Open the USB interface to the probe for sending commands."""
        raise NotImplementedError()

    def close(self) -> None:
        """@brief Close the probe's USB interface."""
        raise NotImplementedError()

    def lock(self) -> None:
        """@brief Lock the probe from access by other threads.

        This lock is recursive, so locking multiple times from a single thread is acceptable as long
        as the thread unlocks the same number of times.

        This method does not return until the calling thread has ownership of the lock.
        """
        self._lock.acquire()

    def unlock(self) -> None:
        """@brief Unlock the probe.

        Only when the thread unlocks the probe the same number of times it has called lock() will
        the lock actually be released and other threads allowed access.
        """
        self._lock.release()

    ## @name Target control
    ##@{

    def connect(self, protocol: Optional[Protocol] = None) -> None:
        """@brief Initialize DAP IO pins for JTAG or SWD"""
        raise NotImplementedError()

    def disconnect(self) -> None:
        """@brief Deinitialize the DAP I/O pins"""
        raise NotImplementedError()

    def swj_sequence(self, length: int, bits: int) -> None:
        """@brief Transfer some number of bits on SWDIO/TMS.

        @param self
        @param length Number of bits to transfer. Must be less than or equal to 256.
        @param bits Integer of the bit values to send on SWDIO/TMS. The LSB is transmitted first.
        """
        pass

    def swd_sequence(self, sequences: Sequence[Union[Tuple[int], Tuple[int, int]]]) -> Tuple[int, Sequence[bytes]]:
        """@brief Send a sequences of bits on the SWDIO signal.

        Each sequence in the _sequences_ parameter is a tuple with 1 or 2 members in this order:
        - 0: int: number of TCK cycles from 1-64
        - 1: int: the SWDIO bit values to transfer. The presence of this tuple member indicates the sequence is
            an output sequence; the absence means that the specified number of TCK cycles of SWDIO data will be
            read and returned.

        @param self
        @param sequences A sequence of sequence description tuples as described above.

        @return A 2-tuple of the response status, and a sequence of bytes objects, one for each input
            sequence. The length of the bytes object is (<TCK-count> + 7) / 8. Bits are in LSB first order.
        """
        raise NotImplementedError()

    def jtag_sequence(self, cycles: int, tms: int, read_tdo: bool, tdi: int) -> Optional[int]:
        """@brief Send JTAG sequence.

        @param self
        @param cycles Number of TCK cycles, from 1-64.
        @param tms Fixed TMS value. Either 0 or 1.
        @param read_tdo Boolean indicating whether TDO should be read.
        @param tdi Integer with the TDI bit values to be transferred each TCK cycle. The LSB is
            sent first.

        @return Either an integer with TDI bit values, or None, if _read_tdo_ was false.
        """
        raise NotImplementedError()

    def set_clock(self, frequency: float) -> None:
        """@brief Set the frequency for JTAG and SWD in Hz.

        This function is safe to call before connect is called.
        """
        raise NotImplementedError()

    def reset(self) -> None:
        """@brief Perform a hardware reset of the target."""
        raise NotImplementedError()

    def assert_reset(self, asserted: bool) -> None:
        """@brief Assert or de-assert target's nRESET signal.

        Because nRESET is negative logic and usually open drain, passing True will drive it low, and
        passing False will stop driving so nRESET will be pulled up.
        """
        raise NotImplementedError()

    def is_reset_asserted(self) -> bool:
        """@brief Returns True if nRESET is asserted or False if de-asserted.

        If the debug probe cannot actively read the reset signal, the value returned will be the
        last value passed to assert_reset().
        """
        raise NotImplementedError()

    def flush(self) -> None:
        """@brief Write out all unsent commands.

        This API may be a no-op for certain debug probe types.
        """
        pass

    def read_pins(self, group: PinGroup, mask: int) -> int:
        """@brief Read values of selected debug probe pins.

        See DebugProbe.ProtocolPin for mask values for the DebugProbe.PinGroup.PROTOCOL_PINS group.

        This method is only expected to be implemented if Capability.PIN_ACCESS is present.

        @param self
        @param group Select the pin group to read.
        @param mask Bit mask indicating which pins will be read. The return value will contain only
            bits set in this mask.
        @return Bit mask with the current value of selected pins at each pin's relevant bit position.
        """
        raise NotImplementedError()

    def write_pins(self, group: PinGroup, mask: int, value: int) -> None:
        """@brief Set values of selected debug probe pins.

        See DebugProbe.ProtocolPin for mask values for the DebugProbe.PinGroup.PROTOCOL_PINS group.
        Note that input-only pins such as TDO are not writable with most debug probes.

        This method is only expected to be implemented if Capability.PIN_ACCESS is present.

        @param self
        @param group Select the pin group to read.
        @param mask Bit mask indicating which pins will be written.
        @param value Mask containing the bit value of to written for selected pins at each pin's
            relevant bit position..
        """
        raise NotImplementedError()

    ##@}

    ## @name DAP access
    ##@{

    @overload
    def read_dp(self, addr: int) -> int:
        ...

    @overload
    def read_dp(self, addr: int, now: Literal[True] = True) -> int:
        ...

    @overload
    def read_dp(self, addr: int, now: Literal[False]) -> Callable[[], int]:
        ...

    @overload
    def read_dp(self, addr: int, now: bool) -> Union[int, Callable[[], int]]:
        ...

    def read_dp(self, addr: int, now: bool = True) -> Union[int, Callable[[], int]]:
        """@brief Read a DP register.

        @param self
        @param addr Integer register address being one of (0x0, 0x4, 0x8, 0xC).
        @param now Boolean specifying whether the read is synchronous (True) or asynchronous.
        @return If _now_ is True, the register's 32-bit value is returned as an integer. When _now_
            is False, a callable is returned that when invoked will return the register's value.
        """
        raise NotImplementedError()

    def write_dp(self, addr: int, data: int) -> None:
        """@brief Write a DP register.

        @param self
        @param addr Integer register address being one of (0x0, 0x4, 0x8, 0xC).
        @param data Integer register value.
        """
        raise NotImplementedError()

    @overload
    def read_ap(self, addr: int) -> int:
        ...

    @overload
    def read_ap(self, addr: int, now: Literal[True] = True) -> int:
        ...

    @overload
    def read_ap(self, addr: int, now: Literal[False]) -> Callable[[], int]:
        ...

    @overload
    def read_ap(self, addr: int, now: bool) -> Union[int, Callable[[], int]]:
        ...

    def read_ap(self, addr: int, now: bool = True) -> Union[int, Callable[[], int]]:
        """@brief Read an AP register."""
        raise NotImplementedError()

    def write_ap(self, addr: int, data) -> None:
        """@brief Write an AP register."""
        raise NotImplementedError()

    @overload
    def read_ap_multiple(self, addr: int, count: int = 1) -> Sequence[int]:
        ...

    @overload
    def read_ap_multiple(self, addr: int, count: int, now: Literal[True] = True) -> Sequence[int]:
        ...

    @overload
    def read_ap_multiple(self, addr: int, count: int, now: Literal[False]) -> Callable[[], Sequence[int]]:
        ...

    @overload
    def read_ap_multiple(self, addr: int, count: int, now: bool) -> Union[Sequence[int], Callable[[], Sequence[int]]]:
        ...

    def read_ap_multiple(self, addr: int, count: int = 1, now: bool = True) \
             -> Union[Sequence[int], Callable[[], Sequence[int]]]:
        """@brief Read one AP register multiple times."""
        raise NotImplementedError()

    def write_ap_multiple(self, addr: int, values) -> None:
        """@brief Write one AP register multiple times."""
        raise NotImplementedError()

    def get_memory_interface_for_ap(self, ap_address: APAddressBase) -> Optional[MemoryInterface]:
        """@brief Returns a @ref pyocd.core.memory_interface.MemoryInterface "MemoryInterface" for
            the specified AP.

        Some debug probe types have accelerated memory read and write commands. This method is used
        to get a concrete @ref pyocd.core.memory_interface.MemoryInterface "MemoryInterface"
        instance that is specific to the AP identified by the _ap_address_ parameter. If the probe
        does not provide an accelerated memory interface, None will be returned.

        @param self The debug probe.
        @param ap_address An instance of @ref pyocd.coresight.ap.APAddressBase "APAddressBase".
        """
        return None

    ##@}

    ## @name SWO
    ##@{

    def swo_start(self, baudrate: float) -> None:
        """@brief Start receiving SWO data at the given baudrate.

        Once SWO reception has started, the swo_read() method must be called at regular intervals
        to receive SWO data. If this is not done, the probe's internal SWO data buffer may overflow
        and data will be lost.
        """
        raise NotImplementedError()

    def swo_stop(self) -> None:
        """@brief Stop receiving SWO data."""
        raise NotImplementedError()

    def swo_read(self) -> bytearray:
        """@brief Read buffered SWO data from the target.

        @eturn Bytearray of the received data. May be 0 bytes in length if no SWO data is buffered
            at the probe.
        """
        raise NotImplementedError()

    ##@}

    def __repr__(self):
        return "<{}@{:x} {}>".format(self.__class__.__name__, id(self), self.description)