servo/drv/cros_ec_softrec_power.py

# Copyright (c) 2014 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 time

import cros_ec_power


class crosEcSoftrecPower(cros_ec_power.CrosECPower):

  """Driver for power_state that uses the EC to trigger recovery.

  A number of boards (generally, the ARM based boards and some x86
  based board) require using the EC to trigger recovery mode.
  """
  # Recovery types.
  _REC_TYPE_REC_ON = 'rec_on'
  _REC_TYPE_REC_OFF = 'rec_off'
  _REC_TYPE_REC_OFF_CLEARB = 'rec_off_clearb'
  _REC_TYPE_FASTBOOT = 'fastboot'

  # Corresponding hostevent commands entered on the EC.
  _HOSTEVENT_CMD_REC_ON = 'hostevent set 0x4000'
  _HOSTEVENT_CMD_REC_OFF = 'hostevent clear 0x4000'
  _HOSTEVENT_CMD_REC_OFF_CLEARB = 'hostevent clearb 0x4000'
  _HOSTEVENT_CMD_FASTBOOT = 'hostevent set 0x1000000'

  _REC_TYPE_HOSTEVENT_CMD_DICT = {
    _REC_TYPE_REC_ON : _HOSTEVENT_CMD_REC_ON,
    _REC_TYPE_REC_OFF : _HOSTEVENT_CMD_REC_OFF,
    _REC_TYPE_REC_OFF_CLEARB : _HOSTEVENT_CMD_REC_OFF_CLEARB,
    _REC_TYPE_FASTBOOT : _HOSTEVENT_CMD_FASTBOOT
  }

  # Time in seconds to allow the EC to pick up the recovery
  # host event.
  _RECOVERY_DETECTION_DELAY = 1

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

    Args:
      interface: driver interface object
      params: dictionary of params
    """
    super(crosEcSoftrecPower, self).__init__(interface, params)
    self._boot_to_rec_screen_delay = float(
      self._params.get('boot_to_rec_screen_delay', 5.0))

  def _power_on_ap(self):
    """Power on the AP after initializing recovery state."""
    self._interface.power_short_press()

  def _power_on_bytype(self, rec_mode, rec_type=_REC_TYPE_REC_ON):
    self._interface.set('ec_uart_cmd', '\r')
    if rec_mode == self.REC_ON:
      try:
        # Before proceeding, we should really check that the EC has reset from
        # our command.  Pexpect is minimally greedy so we won't be able to match
        # the exact reset cause string.  But, this should be good enough.
        self._interface.set('ec_uart_regexp', '["Reset cause:"]')
        self._interface.set('ec_uart_cmd', 'reboot ap-off')
      finally:
        self._interface.set('ec_uart_regexp', 'None')
      time.sleep(self._reset_recovery_time)
    else:
      # Need to clear the flag in secondary (B) copy of the host events if
      # we're in non-recovery mode.
      cmd = self._REC_TYPE_HOSTEVENT_CMD_DICT[self._REC_TYPE_REC_OFF_CLEARB]
      try:
        self._interface.set('ec_uart_regexp', '["Events:"]')
        self._interface.set('ec_uart_cmd', cmd)
      finally:
        self._interface.set('ec_uart_regexp', 'None')

    # Tell the EC to tell the CPU we're in recovery mode or non-recovery mode.
    cmd = self._REC_TYPE_HOSTEVENT_CMD_DICT[rec_type]
    try:
      self._interface.set('ec_uart_regexp', '["Events:"]')
      self._interface.set('ec_uart_cmd', cmd)
    finally:
      self._interface.set('ec_uart_regexp', 'None')
    time.sleep(self._RECOVERY_DETECTION_DELAY)
    self._power_on_ap()
    if rec_mode == self.REC_ON:
      # Allow time to reach the recovery screen before yielding control.
      time.sleep(self._boot_to_rec_screen_delay)

  def _power_on(self, rec_mode):
    if rec_mode == self.REC_ON:
      rec_type = self._REC_TYPE_REC_ON
    else:
      rec_type = self._REC_TYPE_REC_OFF

    self._power_on_bytype(rec_mode, rec_type)

  def _power_on_fastboot(self):
    self._power_on_bytype(self.REC_ON, rec_type=self._REC_TYPE_FASTBOOT)