2930d000ff
The RTC on TI CC13X2/CC26X2 is a 32 KHz clock for which the minimum compare delay is 3 ticks. When using it as the system clock, we need to relax the upper bound to ensure the test succeeds. Signed-off-by: Vincent Wan <vincent.wan@linaro.org>
94 lines
2.7 KiB
C
94 lines
2.7 KiB
C
/*
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* Copyright (c) 2019 Intel Corp.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <ztest.h>
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#include <zephyr.h>
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/*
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* precision timing tests in an emulation environment are not reliable.
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* if the test passes at least once, we know it works properly, so we
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* attempt to repeat the test RETRIES times before reporting failure.
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*/
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#define RETRIES 10
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/*
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* We need to know how many ticks will elapse when we ask for the
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* shortest possible tick timeout. That's generally 1, but in some
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* cases it may be more. On Nordic paths that take 5 or 6 ticks may
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* be observed depending on clock stability and alignment. The base
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* rate assumes 3 ticks for non-timeout effects so increase the
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* maximum effect of timeout to 3 ticks on this platform.
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*/
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#if defined(CONFIG_NRF_RTC_TIMER) && (CONFIG_SYS_CLOCK_TICKS_PER_SEC > 16384)
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#define MAXIMUM_SHORTEST_TICKS 3
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/*
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* Similar situation for TI CC13X2/CC26X2 RTC due to the limitation
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* that a value too close to the current time cannot be loaded to
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* its comparator.
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*/
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#elif defined(CONFIG_CC13X2_CC26X2_RTC_TIMER) && \
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(CONFIG_SYS_CLOCK_TICKS_PER_SEC > 16384)
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#define MAXIMUM_SHORTEST_TICKS 3
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#else
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#define MAXIMUM_SHORTEST_TICKS 1
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#endif
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/*
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* Theory of operation: we can't use absolute units (e.g., "sleep for
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* 10us") in testing k_usleep() because the granularity of sleeps is
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* highly dependent on the hardware's capabilities and kernel
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* configuration. Instead, we test that k_usleep() actually sleeps for
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* the minimum possible duration, which is nominally two ticks. So,
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* we loop k_usleep()ing for as many iterations as should comprise a
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* second, and check to see that a total of one second has elapsed.
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*/
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#define LOOPS (CONFIG_SYS_CLOCK_TICKS_PER_SEC / 2)
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/* It should never iterate faster than the tick rate. However the
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* app, sleep, and timeout layers may each add a tick alignment with
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* fast tick rates, and cycle layer may inject another to guarantee
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* the timeout deadline is met.
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*/
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#define LOWER_BOUND_MS ((1000 * LOOPS) / CONFIG_SYS_CLOCK_TICKS_PER_SEC)
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#define UPPER_BOUND_MS (((3 + MAXIMUM_SHORTEST_TICKS) * 1000 * LOOPS) \
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/ CONFIG_SYS_CLOCK_TICKS_PER_SEC)
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void test_usleep(void)
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{
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int retries = 0;
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s64_t elapsed_ms;
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while (retries < RETRIES) {
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s64_t start_ms;
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s64_t end_ms;
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int i;
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++retries;
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start_ms = k_uptime_get();
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for (i = 0; i < LOOPS; ++i) {
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k_usleep(1);
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}
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end_ms = k_uptime_get();
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elapsed_ms = end_ms - start_ms;
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/* if at first you don't succeed, keep sucking. */
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if ((elapsed_ms >= LOWER_BOUND_MS) &&
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(elapsed_ms <= UPPER_BOUND_MS)) {
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break;
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}
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}
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printk("elapsed_ms = %lld\n", elapsed_ms);
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zassert_true(elapsed_ms >= LOWER_BOUND_MS, "short sleep");
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zassert_true(elapsed_ms <= UPPER_BOUND_MS, "overslept");
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}
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