1 files changed, 54 insertions, 0 deletions
diff --git a/test/timer_calib.py b/test/timer_calib.py
new file mode 100644
index 0000000000..d62e9f7634
--- /dev/null
+++ b/test/timer_calib.py
@@ -0,0 +1,54 @@
+# Copyright (c) 2011 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.
+#
+# Check timers behavior
+#
+
+import time
+
+def one_pass(helper):
+      helper.wait_output("=== Timer calibration ===")
+      res = helper.wait_output("back-to-back get_time : (?P<lat>[0-9]+) us",
+                               use_re=True)["lat"]
+      minlat = int(res)
+      helper.trace("get_time latency %d us\n" % minlat)
+
+      helper.wait_output("sleep 1s")
+      t0 = time.time()
+      second = helper.wait_output("done. delay = (?P<second>[0-9]+) us",
+                               use_re=True)["second"]
+      t1 = time.time()
+      secondreal = t1 - t0
+      secondlat = int(second) - 1000000
+      helper.trace("1s timer latency %d us / real time %f s\n" % (secondlat,
+                                                                  secondreal))
+
+
+      us = {}
+      for pow2 in range(7):
+          delay = 1 << (7-pow2)
+          us[delay] = helper.wait_output("%d us => (?P<us>[0-9]+) us" % delay,
+                                  use_re=True)["us"]
+      helper.wait_output("Done.")
+
+      return minlat, secondlat, secondreal
+
+
+def test(helper):
+      one_pass(helper)
+
+      helper.ec_command("reboot")
+      helper.wait_output("--- Chrome EC initialized! ---")
+
+      # get the timing results on the second pass
+      # to avoid binary translation overhead
+      minlat, secondlat, secondreal = one_pass(helper)
+
+      # check that the timings somewhat make sense
+      if minlat > 220 or secondlat > 500 or abs(secondreal-1.0) > 0.200:
+           helper.fail("imprecise timings " +
+                       "(get_time %d us sleep %d us / real time %.3f s)" %
+                       (minlat, secondlat, secondreal))
+
+      return True # PASS !