In mbed-os-tests-mbed_hal-common_tickers/Microsecond ticker overflow test, some targets
would fail to catch specified ticker value near overflow in time and so fail. This commit
alleviates the issue by checking ticker value range rather than one exact ticker value near
overflow.
Serial buffer must be flushed before entering deep sleep mode. In the test this is done by the additional delay which is implemented on the busy loop which decrements given value down to 0 (`void wait_cycles(volatile unsigned int cycles)`). This solution is not appropriate since it is very target specific and the cycles value has been already increased few times. Additionally very big number of loop cycles which is suitable for fast targets may take much longer on slower boards and results in test timeout.
It has been verified that 20ms is sufficient delay for the green-tea transmission. In this test we cannot simply use `wait_ms(20)` since this potentially may put board to sleep and wake up using lp ticker. The test re-initialzies the lp ticker(disables ticker interrupt) and this operation may break the schedule and time tracing by the upper layer. But we can use us ticker which is not affected by this test. The solution is to add a delay routine based on busy loop and us ticker only. This way are able to wait exactly 20 ms.
Mark mbed-os-tests-mbed_hal-common_tickers/time_cpu_cycles not in-lined.
Otherwise, time_cpu_cycles may be in-lined somewhere and takes different
CPU cycles on invocation.
Increases tolerance value for sleep_usticker_test to cover extra time needed
for cpu stats computation (for more details see MBED_CPU_STATS_ENABLED).
Prevent scheduling interrupt during ticker initialization (in lp_ticker_init)
while test execution.
In case when base tick count is different than next tick count check first if the difference is equal to 1 tick (this is what we are looking for) if not then decrease the tick count.
Repeat counting process few times before incrementing the number of cycles in case when base tick count is equal to next tick count.
RTC reset test was failing when board has been just powered and RTC reset test was executed for the first time (issue has been detected on CI). In such case RTC initialization takes more time than in futher rtc_init calls. This has impact on green-tea communication. Commands send by host immediately after init command (write, read) were not handled on the device side and no response to the host was provided.
To fix this problem test communication flow has been modified. Device sends ack to the host after RTC init is done. Host sends further RTC commands when ack from the device has been received.
Edit:
There are still some communication issues on the CI. Add ack from the device after each executed command. Increase test timeout and wait after reset.
Since some platforms use RTC for low power timer RTC may be already enabled.
Because of that we will only verify if rtc_isenabled() returns 1 in case when init is done and RTC time is set.
It is possible that the difference between base and next tick count on some platforms is greater than 1, in this case we need to repeat counting with the reduced number of cycles (for slower boards).
If number of cycles has been reduced than base tick count needs to be redefined. This operation is missing and is added by this patch.
It has been noticed on NRF51_DK board that occurrence of system tick have impact on test execution.
NRF51_DK is a slow board with fast us ticker and handling of system tick interrupt takes about 250 us ticker ticks which have huge influence on interrupt tests where interrupt is set to <current count> + 100, 200, 500 ticks.
For NR51_DK US_TICKER_OV_LIMIT needs to be increased since if test is run few times in row sometimes fails. This is because NR51_DK is a slow board (16 MHz) with fast and short us ticker counter 1 MHz/16 bits.
Update the ticker common test to clean up after each case by restoring
the ticker IRQ handler. This allows tickers to function normally after
each case has completed.
- count_ticks: fix counter overflow handling,
- count_ticks: use reg_cycles variable in while loop,
- increment test: reduce number of cycles for slow cores if measure process needs to be repeated (difference is greater than 1).
On slow targets with fast high frequency tickers like NRF51_DK (16 Mhz CPU/1MHz ticker) time window for test case execution without overflow needs to be increased. Add parameter to `overflow_protect` function to be able to set different time window without overflow for us ticker and lp ticker.
Increment test proves that ticker counter is incremented by one.
This is done indirectly for high frequency counters where it is impossible to read 'value' and 'value + 1' in two successive ticker reads.
This check is done indirectly by counting ticker ticks elapsed during execution of N cycles of empty while loop. Unfortunately on slow boards with fast tickers like NRF51_DK(16 MHz CPU/1MHz hf ticker) it is possible that for the same N cycles measured number of elapsed ticks in two successive calls is greater than 1. This patch provides fix for such case - measure operation is repeated with the same number of cycles.
count_ticks() function counts ticker ticks elapsed during execution of N cycles of empty while loop.
In current version N value (cycles) is given as volatile paramater in order to disable possible compiler optimalisation.
There was a problem with measured time on different compilers and additionally results on ARM compiler were unexpected (the difference beetween measured elapsed ticks for the same number of cycles was to large). This might be caused by the memory access in order to store updated variable in memory. To fix this issue given numer of cycles has been stored into register and register is decremented (no memory access).
With this fix count_ticks(NUM_OF_CYCLES, 1) call returns 2500 +/-1 for us ticker ticks using each compiler (K64F).
On some platforms (e.g. K64F) different counters are used for time measurement and interrupt generation.
Because of that we should relax interrupt test case and give additional time before checking if interrupt handler has been executed.
Since according to the ticker requirements min acceptable counter size is 12 bits (low power timer) for which max count is 4095, then all test cases must be executed in this time window.
HAL ticker layer handles overflow and it is not handled in the target ticker drivers.
The intention was to use ticker_overflow_delta equal to 0 for low power ticker tests and ticker_overflow_delta equal to 50 for high frequency ticker tests. Current implementation is invalid since for devices which provide LOW_POWER_TIMER feature delta is equal to 0 and for devices without this feature delta is equal 50.
Since target specific ticker drivers are not ready also features which uses ticker in upper layers may not work correctly and tests for these features.
We need to disable also failing higher level ticker related tests (by adding check if DEVICE_USTICKER symbol is available and raise #error [NOT_SUPPORTED] if not).
Ben Cooke
ccli8
Przemyslaw Stekiel
Maciej Bocianski
David Saada
Marc Emmers
Bartek Szatkowski
Russ Butler
jeromecoutant
Russ Butler