Slight RAM+speed efficiency improvement - read the TCP implementation's
native pbufs, rather than forcing netconn_recv to generate netbuf
wrappers for us. Saves one small lwIP heap allocation per TCP packet
received.
This allows Cypress to deliver middleware libraries with
precompiled libraries for SoftFP ahd HardFP, separated by
component-specific sub-directories:
COMPONENT_SOFTFP/TOOLCHAIN_GCC_ARM/libcy_capsense.a
COMPONENT_HARDFP/TOOLCHAIN_GCC_ARM/libcy_capsense.a
Do not call sleep from the test thread, but let scheduler do it.
And also include the deep sleep latency in the computation of the allowed
delta for deep sleep test case.
At high HCLK rate, M2351 cannot provide zero-wait-state flash performance. Besides,
cache is forcibly turned off for non-secure land for internal reason. We locate
'delay_loop_code' from flash to SRAM to achieve zero-wait-state performance.
On some platforms, if low power ticker interrupt is set to very close value (e.g. timestamp < current tick + 3), then interrupt may not fire. This is one use case of lp ticker wrapper, but not all platforms use the wrapper. Some platforms cheat a bit and in this case, simply schedules interrupt a bit later. The problem has been found while working on the low-level lp ticker wrapper for ST boards which run lp ticker using LPTIM. These platforms have such limitation.
Failing test: tests-mbed_drivers-lp_timeout (Test Case: Zero delay)
In the test scenarion, the lp ticker callback is attached with 0.0 s delay in the loop. The new events are put in the front of the lp ticker event list and interrupt reschedule is performed. Usually, the new event is already expired, interrupt fires immediately and next event from the list is then scheduled (e.g. system tick). When the next event (e.g. system tick) is very close to the current time it might be scheduled a bit later (because of lp ticker limitation). Let's assume that system tick has been delayed by 3 ticks and while inserting new zero delay event, absolute system tick time on the event list has already expired. In this case, zero delay event may be added after the expired system tick event and no reschedule is performed (because the head of the list has not changed). Interrupt also didn't fire yet since it has been delayed, so after return from attach_callback(0) we are still waiting for the delayed interrupt and zero delay callback has not been called instantly.
This may also affect other platforms which use such delays (Cypress, NORDIC, etc.).
The proposition is to add extra condition while adding an event to the event list. If the inserted event is already expired, then perform reschedule immediately.
On some targets like STM family boards with LPTIM enabled an interrupt is triggered on counter rollover.
We need special handling for cases when next_match_timestamp < start_timestamp (interrupt is to be fired after rollover).
In such case after first wake-up we need to reset interrupt and go back to sleep waiting for the valid one.
On some targets like STM family boards with LPTIM enabled there is a required delay (~100 us) before we are able to reprogram LPTIM_COMPARE register back to back.
This is handled by the low level lp ticker wrapper which uses LPTIM_CMPOK interrupt. CMPOK fires when LPTIM_COMPARE register can be safely reprogrammed again.
This means that on these platforms we have additional interrupt (CMPOK) fired always ~100 us after programming lp ticker.
Since this interrupt wake-ups the board from the sleep we need to go to sleep after CMPOK is handled.
Background:
There is an errata in LPTIM specification that explains that CMP Flag
condition is not an exact match (COUNTER = MATCH) but rather a
comparison (COUNTER >= MATCH).
As a consequence the interrupt is firing early than expected when
programing a timestamp after the 0xFFFF wrap-around.
In order to
work-around this issue, we implement the below work-around.
In case timestamp is after the work-around, let's decide to program the
CMP value to 0xFFFF, which is the wrap-around value. There would anyway be
a wake-up at the time of wrap-around to let the OS update the system time.
When the wrap-around interrupt happen, OS will check the current time and
program again the timestamp to the proper value.
Added logic to lock deep sleep when USB is initialized to prevent malfunctioning. This is consistent with the other drivers. See PR ARMmbed/mbed-os#9879
Martin Kojtal
Maciej Bocianski
jeromecoutant
Mirela Chirica
Laurent Meunier
Kimmo Vaisanen
Teppo Järvelin
mudassar-ublox
Kevin Bracey
Qinghao Shi
d-kato
Volodymyr Medvid
Marten Lootsma
Marten Lootsma
Chun-Chieh Li
Filip Jagodzinski
Przemyslaw Stekiel
Chris Trowbridge
Tymoteusz Bloch
George Beckstein