servo/drv/fw_wp_ccd.py

# Copyright 2016 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import fw_wp_state
import pty_driver


class fwWpCcdError(Exception):
  """Exception class for fwWpCcd."""


class fwWpCcd(fw_wp_state.FwWpStateDriver, pty_driver.ptyDriver):
  """Driver for fw_wp_state for boards with CCD."""

  def __init__(self, interface, params):
    """Constructor.

    Args:
      interface: driver interface object
      params: dictionary of params
    """
    super(fwWpCcd, self).__init__(interface, params)

  def _force_on(self):
    """Force the firmware to write-protected."""
    self._issue_cmd("wp on")

  def _force_off(self):
    """Force the firmware to not write-protected."""
    self._issue_cmd("wp off")

  def _reset(self):
    """Reset the firmware write-protection state to the system value."""
    # The WP is totally controlled by CCD chip. Do nothing to reset.
    pass

  def _get_state(self):
    """Get the firmware write-protection state."""
    # The output string is defined in ec/board/cr50/wp.c
    result = self._issue_cmd_get_results(
        "wp", ["Flash WP is (enabled|disabled)"])[0]
    if result is None:
      raise fwWpCcdError("Cannot retrieve wp result on CCD console.")

    if result[1] == "enabled":
      return self._STATE_FORCE_ON
    else:
      return self._STATE_FORCE_OFF