Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

Susheel Nuguru — Thu, 24 Aug 2017 08:11:01 GMT

looks like the commit is not included in 12.x release. Not sure why. Its there in SDK14

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

Dave_couling — Thu, 17 Aug 2017 23:22:55 GMT

Was this fixed in SDK12.3?

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

Susheel Nuguru — Wed, 23 Nov 2016 15:04:29 GMT

PLEASE FOLLOW PATCHES FROM RADOSLAW. I removed my answer to avoid confusion.

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

Susheel Nuguru — Wed, 23 Nov 2016 15:03:02 GMT

Hi Srikar,

Please remove my patches and apply patches from Radoslaw. I think I will have to remove my post now to avoid confusion.

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

Susheel Nuguru — Wed, 16 Nov 2016 08:15:05 GMT

Hi Jules, the GPIO ISR could be masking the sys tick interrupt too long, Could you try to remove the RTT prints in the ISR and see if this improves? if systick interrupt is masked (by other ISRs or by disabling RTOS interrupts) more than 1 ms then there is a good chance that tick interrupts will be lost.

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

jules — Tue, 15 Nov 2016 14:19:48 GMT

Hi Radoslaw, I tried you fix. It works, but I still see a drift between the systick and RTC. I print these values every time I get an interrupt. After 20 minutes, this looks like:

 0> :INFO:Timer callback: tickCount = 955789, RTC = 953942.
 0> :INFO:LED on: tickCount = 955789, RTC = 953942.
 0> :INFO:ISR: tickCount = 955790, RTC = 953943.
 0> :INFO:LED off: tickCount = 955871, RTC = 954023.
 0> :INFO:Timer callback: tickCount = 956815, RTC = 954966.
 0> :INFO:LED on: tickCount = 956815, RTC = 954966.
 0> :INFO:ISR: tickCount = 956816, RTC = 954967.
 0> :INFO:LED off: tickCount = 956897, RTC = 955047.

It does not seem to have any negative effect on my application, but I don't think this behaviour is desirable.

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

jules — Sun, 13 Nov 2016 12:06:49 GMT

yes that is ok. I will test this monday when I'm in the office.

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

Susheel Nuguru — Sun, 13 Nov 2016 10:46:50 GMT

After you validate that it works, i would remove my answer and patches to avoid confusion for others. Hope that is ok for you

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

jules — Sat, 12 Nov 2016 14:06:41 GMT

Ok I will. Thank you all for the good support.

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

Susheel Nuguru — Sat, 12 Nov 2016 13:48:31 GMT

Jules, please remove my patches and apply Radoslaw's fixes. His fixes are cleaner snd should fix most of the problems we see.

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

Radoslaw Koppel — Thu, 10 Nov 2016 15:55:35 GMT

I have created some unit test in our repository and recreate the problem. In attachment I am including quick preview of updated CMSIS port part. Please copy this files into .../freertos/portable: CMSIS.zip

The solution is to lock interrupts little longer, but only application interrupts, not using BASEPRI register - as interrupts blocked this way would not wake up the MCU. It gives a little higher response time for interrupt when in tickless idle. But now it should be safe at last.

The NRF52 port passes perfectly the test. NRF51 seems to miss 1 unexpected tick count. Just including file for reference because we have a holidays tomorow and I would not be able to polish it before the weekend.

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

Susheel Nuguru — Thu, 03 Nov 2016 19:27:00 GMT

Hi dpa, please open a new thread and include project so that i can reproduce the problem.please explain the problem as clearly as possible.

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

dpa — Thu, 03 Nov 2016 15:43:04 GMT

Hi Aryan,

I have updated from SDK12 all the freertos folder and included your port_cmsis_systick.c file with the:

extern void updateRTOSTick(void);

In the portmacro_cmsis.h file. With a call to updateRTOSTick() function in the handlers (gpiote, uart, spi, etc.) that call to freertos api calls (xSemaphoreGive, xTimerResetFromISR, etc.)

But this configuration with:

#define    configUSE_TICKLESS_IDLE                                                   1

Is not working. If I use the SDK12 original files it works but the uarte is not working properly in Rx mode. In a 8 bytes DMA dual buffer a 7 byte frame is received only the 6 first bytes ok and the seventh is captured in the seccond DMA buffer. I am missing something, is there any other thing to modify?

If you think this subject needs to be opened in another thread move it or tell me and i create a new thread, thanks!

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

Susheel Nuguru — Wed, 02 Nov 2016 10:33:08 GMT

Hi dpa,

I updated my answer with the file.

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

dpa — Wed, 02 Nov 2016 10:19:34 GMT

Hi Aryan could you attach the full port_cmsis_systick.c file?

Thanks in advance.

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

Susheel Nuguru — Fri, 28 Oct 2016 13:14:37 GMT

You should use rtos files from sdk 12, there were some fixes in sdk 12 you should not miss. Just copy thefreertos folder from sdk 12 to sdk11. Should be fine. Can you please remind me on monday to attach the full port_cmsis_systick.c file.

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

dpa — Fri, 28 Oct 2016 11:46:40 GMT

This port_cmsis_systick.c modifications can be used for the SDK11?

If so, can you attach the modified port_cmsis_systick.c file, I am using SDK11 and honestly I dont know to to apply the diff.patch.

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

Susheel Nuguru — Thu, 27 Oct 2016 13:15:30 GMT

found the bug, but i think there needs to be some big changes to solve this. The problem was that when gpio_irqhandler is caller in gpio irq context, it is most of the time waking the chip. In tickless mode the RTC counter is ticking but since the interrupts were disabled FreeRTOS tick is way behind when the ISR is called. When we call xTimerResetFromIsr, then the system tick is still not updated and stays the same as the one that was before going to sleep. We need a mechanism to update the tick when an interrupt have woken the chip in tickless mode. I tested this concept with a prototype and i can confirm that this is the problem we are seeing. Would you like to test this aswell? i will attach a patch but PLEASE DO NOT USE THIS PATCH in final product. We need to address this in a better way. patch coming up in a minute.

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

Susheel Nuguru — Thu, 27 Oct 2016 08:27:16 GMT

Hi Jules,

I fixed the bug that was causing the tick difference. but that apparently did not fix the issue of timerreset not functioning in tickless mode. Sorry for pre mature celebrations.

Anyhow you will like to add this fix to your code with this diff

diff --git a/external/freertos/portable/CMSIS/nrf52/port_cmsis_systick.c b/external/freertos/portable/CMSIS/nrf52/port_cmsis_systick.c
index d89381d..868052d 100644
--- a/external/freertos/portable/CMSIS/nrf52/port_cmsis_systick.c
+++ b/external/freertos/portable/CMSIS/nrf52/port_cmsis_systick.c
@@ -266,6 +266,12 @@ void vPortSuppressTicksAndSleep( TickType_t xExpectedIdleTime )
         }
         configPOST_SLEEP_PROCESSING( xExpectedIdleTime );
         nrf_rtc_int_disable(portNRF_RTC_REG, NRF_RTC_INT_COMPARE0_MASK);
+
+        /* If we do not clear this pending bit then interrupt trigger caused by compare0 (compare0 is only used in tickless mode)
+         * pendbit will be confused as TICK in xPortSysTickHandler
+         */
+        NVIC_ClearPendingIRQ(portNRF_RTC_IRQn);
+
         NVIC_EnableIRQ(portNRF_RTC_IRQn);

         /* Correct the system ticks */

This will fix the tick difference issue you are seeing

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

jules — Wed, 26 Oct 2016 13:48:34 GMT

great. Thank you

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

Susheel Nuguru — Wed, 26 Oct 2016 13:43:34 GMT

Hi,

I found the bug, but sorry i am in hurry and i will update you later. The bug is in RTC tick handler. it have a corner case where it increments the rtos counter, so the rtos counter is moving ahead of RTC. More info tomorrow and i will give you a workaround.

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

jules — Wed, 26 Oct 2016 11:55:01 GMT

So in tickless mode, both the led_toggle_task and the timer callback have a tickCount that is around 80 ticks ahead of the RTC. I think this is incorrect behaviour.

Furthermore I'm suprised by the power consumption with tickless mode disabled. I would expect it only to be slightly larger than using tickless mode due to the periodic ISR caused by the ticks. My multimeter however shows 7.54 mA continuous current draw with tickless mode disabled. Is this normal?

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

jules — Wed, 26 Oct 2016 11:48:34 GMT

without tickless mode this looks like this:

     0> :INFO:ISR: tickCount = 14726, RTC = 14726.
 0> :INFO:LED off: tickCount = 14807, RTC = 14807.
 0> :INFO:Timer callback: tickCount = 15750, RTC = 15750.
 0> :INFO:LED on: tickCount = 15750, RTC = 15750.
 0> :INFO:ISR: tickCount = 15750, RTC = 15750.
 0> :INFO:LED off: tickCount = 15831, RTC = 15831.
 0> :INFO:Timer callback: tickCount = 16774, RTC = 16774.
 0> :INFO:LED on: tickCount = 16774, RTC = 16774.
 0> :INFO:ISR: tickCount = 16774, RTC = 16774.
 0> :INFO:LED off: tickCount = 16855, RTC = 16855.
 0> :INFO:Timer callback: tickCount = 17798, RTC = 17798.
 0> :INFO:LED on: tickCount = 17798, RTC = 17798.
 0> :INFO:ISR: tickCount = 17798, RTC = 17798.
 0> :INFO:LED off: tickCount = 17879, RTC = 17879.
 0> :INFO:Timer callback: tickCount = 18822, RTC = 18822.
 0> :INFO:LED on: tickCount = 18822, RTC = 18822.
 0> :INFO:ISR: tickCount = 18822, RTC = 18822.
 0> :INFO:LED off: tickCount = 18903, RTC = 18903.
 0> :INFO:Timer callback: tickCount = 19846, RTC = 19846.
 0> :INFO:LED on: tickCount = 19846, RTC = 19846.
 0> :INFO:ISR: tickCount = 19846, RTC = 19846.
 0> :INFO:LED off: tickCount = 19927, RTC = 19927.

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

jules — Wed, 26 Oct 2016 11:47:22 GMT

Hi Aryan, I got some more info. I added teh RTC values to the systick measurement in tickless mode:

     0> :INFO:ISR: tickCount = 68757, RTC = 68759.
 0> :INFO:LED off: tickCount = 68838, RTC = 68760.
 0> :INFO:Timer callback: tickCount = 69782, RTC = 69703.
 0> :INFO:LED on: tickCount = 69782, RTC = 69703.
 0> :INFO:ISR: tickCount = 69782, RTC = 69783.
 0> :INFO:LED off: tickCount = 69863, RTC = 69784.
 0> :INFO:Timer callback: tickCount = 70807, RTC = 70727.
 0> :INFO:LED on: tickCount = 70807, RTC = 70727.
 0> :INFO:ISR: tickCount = 70807, RTC = 70807.
 0> :INFO:LED off: tickCount = 70888, RTC = 70808.
 0> :INFO:Timer callback: tickCount = 71832, RTC = 71751.
 0> :INFO:LED on: tickCount = 71832, RTC = 71751.
 0> :INFO:ISR: tickCount = 71832, RTC = 71831.
 0> :INFO:LED off: tickCount = 71913, RTC = 71832.

RE: Why is the FreeRTOS function xTimerResetFromISR not working in tickless mode?

jules — Mon, 24 Oct 2016 13:20:21 GMT

Ok I will continue my development in without tickless mode untill this is fixed. Thank you for looking into this.