blob: df233c320fadb4ff4ec0eb1fd197e1ebb688208d [file] [log] [blame]
# Copyright (c) 2012 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 re
import serial as pyserial
from autotest_lib.client.bin import test
from autotest_lib.client.bin import utils
from autotest_lib.client.common_lib import error
from autotest_lib.client.cros import factory_setup_modules
from cros.factory.test import factory
# Modem commands.
# This commands start tracking mode, and run for a while.
START_GPS_TRACKING = 'AT$NWGPSSTART=3,1,64000,1,100,250'
class factory_BasicGPS(test.test):
version = 1
def run_once(self, retry, dev_modem='/dev/ttyUSB0', dev_gps='/dev/ttyUSB3'):
'''Gets raw NMEA data from GPS to ensure the connectivity.
@param dev_modem: Path to modem.
@param dev_gps: Path to extract GPS data.
@param retry: A number indicates times to retry because some GPS
module have its own format, NMEA format might not come
as its first response.
def read_response(serial):
'''Reads response from the modem until a timeout.'''
line = serial.readline()
factory.log('modem[ %r' % line)
return line.rstrip('\r\n')
def send_command(serial, command):
'''Sends a command to the modem and discards the echo.'''
serial.write(command + '\r')
factory.log('modem] %r' % command)
echo = read_response(serial)
def check_response(serial, expected_re):
'''Reads response and checks with a regular expression.'''
response = read_response(serial)
if not re.match(expected_re, response):
raise error.TestError(
'Expected %r but got %r' % (expected_re, response))
def check_valid_nmea(data):
'''Checks whether the data is valid NMEA format.'''
match = re.match(r'\$(.*)\*(\w\w)', data)
if match:
# Examine the checksum.
checksum = 0
for char in
checksum ^= ord(char)
if int(, 16) == checksum:
return True
return False
# Kill off modem manager, which might be holding the device open.
utils.system("stop modemmanager", ignore_status=True)
serial_modem = pyserial.Serial(dev_modem, timeout=2) # Empty the buffer.
serial_gps = pyserial.Serial(dev_gps, timeout=2) # Empty the buffer.
# Send an AT command and expect 'OK'
send_command(serial_modem, 'AT')
check_response(serial_modem, DEVICE_NORMAL_RESPONSE)
# Enable GPS.
send_command(serial_modem, ENABLE_GPS)
send_command(serial_modem, START_GPS_TRACKING)
# See if we can get valid NMEA data.
while retry > 0:
response = read_response(serial_gps)
if check_valid_nmea(response):
retry -= 1
raise error.TestError('No valid NMEA data found')
# Restart the modem manager.
utils.system("start modemmanager", ignore_status=True)
except Exception as e:
factory.log('Exception - %s' % e)