55 lines
1.8 KiB
Python
55 lines
1.8 KiB
Python
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# Copyright 2011 The Chromium OS Authors. All rights reserved.
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# Use of this source code is governed by a BSD-style license that can be
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# found in the LICENSE file.
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#
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# Check timers behavior
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#
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import time
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def one_pass(helper):
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helper.wait_output("=== Timer calibration ===")
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res = helper.wait_output("back-to-back get_time : (?P<lat>[0-9]+) us",
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use_re=True)["lat"]
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minlat = int(res)
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helper.trace("get_time latency %d us\n" % minlat)
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helper.wait_output("sleep 1s")
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t0 = time.time()
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second = helper.wait_output("done. delay = (?P<second>[0-9]+) us",
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use_re=True)["second"]
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t1 = time.time()
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secondreal = t1 - t0
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secondlat = int(second) - 1000000
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helper.trace("1s timer latency %d us / real time %f s\n" % (secondlat,
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secondreal))
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us = {}
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for pow2 in range(7):
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delay = 1 << (7-pow2)
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us[delay] = helper.wait_output("%d us => (?P<us>[0-9]+) us" % delay,
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use_re=True)["us"]
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helper.wait_output("Done.")
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return minlat, secondlat, secondreal
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def test(helper):
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one_pass(helper)
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helper.ec_command("reboot")
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helper.wait_output("--- UART initialized")
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# get the timing results on the second pass
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# to avoid binary translation overhead
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minlat, secondlat, secondreal = one_pass(helper)
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# check that the timings somewhat make sense
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if minlat > 220 or secondlat > 500 or abs(secondreal-1.0) > 0.200:
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helper.fail("imprecise timings " +
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"(get_time %d us sleep %d us / real time %.3f s)" %
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(minlat, secondlat, secondreal))
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return True # PASS !
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