Re: [riot-devel] How to properly use cortexm_sleep

2019-05-29 Thread Kees Bakker 

Thanks

On 29-05-19 13:02, Robert Hartung wrote:

Hey everyone,

let me say a few words as Kaspar and I have been driving the
implementation of this. In general there is no need to manually go to
sleep, as the deepest sleep mode will always be selected from the idle
thread depending on the deepest mode possible.
Which mode is possible depends on the used periphs. For STM32 sleep was
long not possible, as PM_BLOCKER_INITIAL was initialized with 1 for each
mode, which resulted in never going to a sleep mode.
 From what I can see is that it is still initialized with ones?
Nevertheless, to make us of it PM_BLOCKER_INITIAL should be initialized
with 0. All periph modules should then individually block the sleep
modes they can not operate in. For now the biggest problem was the
shell/uart, as it would always block any sleep modes.
An exception are some platforms, as they have a Uart which can wake them
up from sleep modes.

I have modified the atmega1284p implementation to make use of it [0] and
[1].

Best Regards
Robert

[0]
https://github.com/ibr-cm/RIOT/blob/idealvolting-rc1/cpu/atmega1284p/periph/pm.c
[1]
https://github.com/ibr-cm/RIOT/blob/idealvolting-rc1/cpu/atmega_common/periph/

On 28.05.19 20:01, Kees Bakker wrote:

Nice,

Thanks for sharing

On 28-05-19 08:48, Oleg Artamonov wrote:

Hi.

Yes, but for emergency reboots only.
  
Implementations:

https://github.com/unwireddevices/RIOT/blob/loralan-public/cpu/stm32_common/periph/iwdg.c
and
https://github.com/unwireddevices/RIOT/blob/loralan-public/cpu/nrf5x_common/periph/iwdg.c
  
For task scheduling on sleepy devices we use RTC-based timers with 1

ms resolution and 1 week max period
(https://github.com/unwireddevices/RIOT/tree/loralan-public/sys/rtctimers-millis;
on STM32L, we use regular HW RTC with SSR register, on nRF52 —
"software" RTC implemented on top of HW RTT unit).
  
--

/Sincerely yours,/
/Oleg Artamonov/
/+7 (916) 631-34-90/
/www.unwds.com/ 
  
  
  
27.05.2019, 21:57, "Kees Bakker" :


 Hey Oleg,

 Are you using the watchdog?
  
 On 27-05-19 07:30, Oleg Artamonov wrote:


 Hi
  
 We do. On STM32L0, STM32L1, nRF52, etc.
  
 Checking for interrupt flags is absolutely useless here - 1)

 WFI checks for any relevant interrupt flags, 2) interrupt
 still can happen between check and WFI.
  
 --

 /Sincerely yours,/
 /Oleg Artamonov/
 /+7 (916) 631-34-90/
 /www.unwds.com/ 
  
  
  
 26.05.2019, 18:40, "Kees Bakker" 

 :

 Hey

 Is there anyone using cortexm_sleep for a real
 application? And if
 yes, would you want to share how exactly that's done?

 Let me say that I've never written a real application with
 RIOT, but
 I would like to. One of the important requirements is that
 the app
 must be in sleep (deep sleep) and only wake up to do some
 work.
 And another requirement is to use the watchdog.

 That said, I'm familiar with the following Arduino pseudo
 code.

  while (forever) {
  do stuff

  disable interrupts
  if !certain condition
  __WFI();
  enable interrupts
  }

 That "certain condition" is mostly checking that no WDT or
 RTC interrupt
 occurred before disabling the interrupts. These interrupts
 are handled
 by ISR's and they set a flag. This is a fairly common
 thing to do, I think.

 I don't see (or understand) how this can be achieved with
 RIOT-OS and
 cortexm_sleep. It is essential to check the condition
 AFTER disabling the
 interrupts.

 --
 Kees Bakker
 ___
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 devel@riot-os.org 
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Re: [riot-devel] How to properly use cortexm_sleep

2019-05-29 Thread Robert Hartung 
Hey everyone,

let me say a few words as Kaspar and I have been driving the
implementation of this. In general there is no need to manually go to
sleep, as the deepest sleep mode will always be selected from the idle
thread depending on the deepest mode possible.
Which mode is possible depends on the used periphs. For STM32 sleep was
long not possible, as PM_BLOCKER_INITIAL was initialized with 1 for each
mode, which resulted in never going to a sleep mode.
From what I can see is that it is still initialized with ones?
Nevertheless, to make us of it PM_BLOCKER_INITIAL should be initialized
with 0. All periph modules should then individually block the sleep
modes they can not operate in. For now the biggest problem was the
shell/uart, as it would always block any sleep modes.
An exception are some platforms, as they have a Uart which can wake them
up from sleep modes.

I have modified the atmega1284p implementation to make use of it [0] and
[1].

Best Regards
Robert

[0]
https://github.com/ibr-cm/RIOT/blob/idealvolting-rc1/cpu/atmega1284p/periph/pm.c
[1]
https://github.com/ibr-cm/RIOT/blob/idealvolting-rc1/cpu/atmega_common/periph/

On 28.05.19 20:01, Kees Bakker wrote:
> Nice,
> 
> Thanks for sharing
> 
> On 28-05-19 08:48, Oleg Artamonov wrote:
>> Hi.
>>
>> Yes, but for emergency reboots only.
>>  
>> Implementations:
>> https://github.com/unwireddevices/RIOT/blob/loralan-public/cpu/stm32_common/periph/iwdg.c
>> and
>> https://github.com/unwireddevices/RIOT/blob/loralan-public/cpu/nrf5x_common/periph/iwdg.c
>>  
>> For task scheduling on sleepy devices we use RTC-based timers with 1
>> ms resolution and 1 week max period
>> (https://github.com/unwireddevices/RIOT/tree/loralan-public/sys/rtctimers-millis;
>> on STM32L, we use regular HW RTC with SSR register, on nRF52 —
>> "software" RTC implemented on top of HW RTT unit).
>>  
>> -- 
>> /Sincerely yours,/
>> /Oleg Artamonov/
>> /+7 (916) 631-34-90/
>> /www.unwds.com/ 
>>  
>>  
>>  
>> 27.05.2019, 21:57, "Kees Bakker" :
>>
>> Hey Oleg,
>>
>> Are you using the watchdog?
>>  
>> On 27-05-19 07:30, Oleg Artamonov wrote:
>>
>> Hi
>>  
>> We do. On STM32L0, STM32L1, nRF52, etc.
>>  
>> Checking for interrupt flags is absolutely useless here - 1)
>> WFI checks for any relevant interrupt flags, 2) interrupt
>> still can happen between check and WFI.
>>  
>> -- 
>> /Sincerely yours,/
>> /Oleg Artamonov/
>> /+7 (916) 631-34-90/
>> /www.unwds.com/ 
>>  
>>  
>>  
>> 26.05.2019, 18:40, "Kees Bakker" 
>> :
>>
>> Hey
>>
>> Is there anyone using cortexm_sleep for a real
>> application? And if
>> yes, would you want to share how exactly that's done?
>>
>> Let me say that I've never written a real application with
>> RIOT, but
>> I would like to. One of the important requirements is that
>> the app
>> must be in sleep (deep sleep) and only wake up to do some
>> work.
>> And another requirement is to use the watchdog.
>>
>> That said, I'm familiar with the following Arduino pseudo
>> code.
>>
>>  while (forever) {
>>  do stuff
>>
>>  disable interrupts
>>  if !certain condition
>>  __WFI();
>>  enable interrupts
>>  }
>>
>> That "certain condition" is mostly checking that no WDT or
>> RTC interrupt
>> occurred before disabling the interrupts. These interrupts
>> are handled
>> by ISR's and they set a flag. This is a fairly common
>> thing to do, I think.
>>
>> I don't see (or understand) how this can be achieved with
>> RIOT-OS and
>> cortexm_sleep. It is essential to check the condition
>> AFTER disabling the
>> interrupts.
>>
>> --
>> Kees Bakker
>> ___
>> devel mailing list
>> devel@riot-os.org 
>> https://lists.riot-os.org/mailman/listinfo/devel
>>
>>  
>>
>> ___
>> devel mailing list
>> devel@riot-os.org 
>> https://lists.riot-os.org/mailman/listinfo/devel
>>
>> ,
>>
>> ___
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>> devel@riot-os.org 
>> https://lists.riot-os.org/mailman/listinfo/devel
>>
>>
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>> devel@riot-os.org
>>

Re: [riot-devel] How to properly use cortexm_sleep

2019-05-28 Thread Kees Bakker 

Nice,

Thanks for sharing

On 28-05-19 08:48, Oleg Artamonov wrote:

Hi.

Yes, but for emergency reboots only.
Implementations: 
https://github.com/unwireddevices/RIOT/blob/loralan-public/cpu/stm32_common/periph/iwdg.c 
and 
https://github.com/unwireddevices/RIOT/blob/loralan-public/cpu/nrf5x_common/periph/iwdg.c
For task scheduling on sleepy devices we use RTC-based timers with 1 
ms resolution and 1 week max period 
(https://github.com/unwireddevices/RIOT/tree/loralan-public/sys/rtctimers-millis; 
on STM32L, we use regular HW RTC with SSR register, on nRF52 — 
"software" RTC implemented on top of HW RTT unit).

--
/Sincerely yours,/
/Oleg Artamonov/
/+7 (916) 631-34-90/
/www.unwds.com/ 
27.05.2019, 21:57, "Kees Bakker" :

Hey Oleg,

Are you using the watchdog?
On 27-05-19 07:30, Oleg Artamonov wrote:

Hi
We do. On STM32L0, STM32L1, nRF52, etc.
Checking for interrupt flags is absolutely useless here - 1)
WFI checks for any relevant interrupt flags, 2) interrupt
still can happen between check and WFI.
-- 
/Sincerely yours,/

/Oleg Artamonov/
/+7 (916) 631-34-90/
/www.unwds.com/ 
26.05.2019, 18:40, "Kees Bakker" 
:

Hey

Is there anyone using cortexm_sleep for a real
application? And if
yes, would you want to share how exactly that's done?

Let me say that I've never written a real application with
RIOT, but
I would like to. One of the important requirements is that
the app
must be in sleep (deep sleep) and only wake up to do some
work.
And another requirement is to use the watchdog.

That said, I'm familiar with the following Arduino pseudo
code.

 while (forever) {
 do stuff

 disable interrupts
 if !certain condition
 __WFI();
 enable interrupts
 }

That "certain condition" is mostly checking that no WDT or
RTC interrupt
occurred before disabling the interrupts. These interrupts
are handled
by ISR's and they set a flag. This is a fairly common
thing to do, I think.

I don't see (or understand) how this can be achieved with
RIOT-OS and
cortexm_sleep. It is essential to check the condition
AFTER disabling the
interrupts.

--
Kees Bakker
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Re: [riot-devel] How to properly use cortexm_sleep

2019-05-28 Thread Oleg Artamonov 
Hi.Yes, but for emergency reboots only. Implementations: https://github.com/unwireddevices/RIOT/blob/loralan-public/cpu/stm32_common/periph/iwdg.c and https://github.com/unwireddevices/RIOT/blob/loralan-public/cpu/nrf5x_common/periph/iwdg.c For task scheduling on sleepy devices we use RTC-based timers with 1 ms resolution and 1 week max period (https://github.com/unwireddevices/RIOT/tree/loralan-public/sys/rtctimers-millis; on STM32L, we use regular HW RTC with SSR register, on nRF52 — "software" RTC implemented on top of HW RTT unit). -- Sincerely yours,Oleg Artamonov+7 (916) 631-34-90www.unwds.com   27.05.2019, 21:57, "Kees Bakker" :Hey Oleg,Are you using the watchdog? On 27-05-19 07:30, Oleg Artamonov wrote:Hi We do. On STM32L0, STM32L1, nRF52, etc. Checking for interrupt flags is absolutely useless here - 1) WFI checks for any relevant interrupt flags, 2) interrupt still can happen between check and WFI. -- Sincerely yours,Oleg Artamonov+7 (916) 631-34-90www.unwds.com   26.05.2019, 18:40, "Kees Bakker" :HeyIs there anyone using cortexm_sleep for a real application? And ifyes, would you want to share how exactly that's done?Let me say that I've never written a real application with RIOT, butI would like to. One of the important requirements is that the appmust be in sleep (deep sleep) and only wake up to do some work.And another requirement is to use the watchdog.That said, I'm familiar with the following Arduino pseudo code. while (forever) { do stuff disable interrupts if !certain condition __WFI(); enable interrupts }That "certain condition" is mostly checking that no WDT or RTC interruptoccurred before disabling the interrupts. These interrupts are handledby ISR's and they set a flag. This is a fairly common thing to do, I think.I don't see (or understand) how this can be achieved with RIOT-OS andcortexm_sleep. It is essential to check the condition AFTER disabling theinterrupts.--Kees Bakker___devel mailing listdevel@riot-os.orghttps://lists.riot-os.org/mailman/listinfo/devel ___
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Re: [riot-devel] How to properly use cortexm_sleep

2019-05-27 Thread Kees Bakker 

Thanks Juan,

That's a lot of information to digest. It will take me a bit of time
to go through.
-- Kees

On 27-05-19 14:17, Juan Ignacio Carrano wrote:

Hi Kees,

Some observations:

1- WFI will not send you to the deepest sleep states- clocks are 
gated, but many things remain powered.


2- If you are using the timer module and depending on you clock 
configuration you may experience more or less frequent wake ups. 
Whether this is acceptable is up to you.


3- Normally, if no thread is runnable (i.e. all are waiting/blocked) the
idle thread is run and that has a loop which sends the MCU to the 
deepest state possible (considering the currently-enabled 
peripherals). This means that in many cases the explicit WFI is not 
needed if in your
"while(forever)" loop you put some call that blocks waiting for the 
events you are interested in.


The interaction between (1) and (3) means that by doing a WFI in a 
thread it is possible that you don't sleep as deep as you could:


- The current thread will be blocked on the WFI instruction until an
  event arrives.
- In the meantime, control will not go back to the kernel.
- This means the idle thread will not run (from the schedulers point of
  view, you thread is still running).
- The pm_whatever() call in the idle thread will not run.

In conclusion, try to use the default mechanism if you can.

Regards,

Juan.
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Re: [riot-devel] How to properly use cortexm_sleep

2019-05-27 Thread Kees Bakker 

Hey Oleg,

Are you using the watchdog?

On 27-05-19 07:30, Oleg Artamonov wrote:

Hi
We do. On STM32L0, STM32L1, nRF52, etc.
Checking for interrupt flags is absolutely useless here - 1) WFI 
checks for any relevant interrupt flags, 2) interrupt still can happen 
between check and WFI.

--
/Sincerely yours,/
/Oleg Artamonov/
/+7 (916) 631-34-90/
/www.unwds.com/ 
26.05.2019, 18:40, "Kees Bakker" :

Hey

Is there anyone using cortexm_sleep for a real application? And if
yes, would you want to share how exactly that's done?

Let me say that I've never written a real application with RIOT, but
I would like to. One of the important requirements is that the app
must be in sleep (deep sleep) and only wake up to do some work.
And another requirement is to use the watchdog.

That said, I'm familiar with the following Arduino pseudo code.

 while (forever) {
 do stuff

 disable interrupts
 if !certain condition
 __WFI();
 enable interrupts
 }

That "certain condition" is mostly checking that no WDT or RTC
interrupt
occurred before disabling the interrupts. These interrupts are handled
by ISR's and they set a flag. This is a fairly common thing to do,
I think.

I don't see (or understand) how this can be achieved with RIOT-OS and
cortexm_sleep. It is essential to check the condition AFTER
disabling the
interrupts.

--
Kees Bakker
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Re: [riot-devel] How to properly use cortexm_sleep

2019-05-27 Thread Juan Ignacio Carrano 

Hi Kees,

Some observations:

1- WFI will not send you to the deepest sleep states- clocks are gated, 
but many things remain powered.


2- If you are using the timer module and depending on you clock 
configuration you may experience more or less frequent wake ups. Whether

this is acceptable is up to you.

3- Normally, if no thread is runnable (i.e. all are waiting/blocked) the
idle thread is run and that has a loop which sends the MCU to the 
deepest state possible (considering the currently-enabled peripherals). 
This means that in many cases the explicit WFI is not needed if in your
"while(forever)" loop you put some call that blocks waiting for the 
events you are interested in.


The interaction between (1) and (3) means that by doing a WFI in a 
thread it is possible that you don't sleep as deep as you could:


- The current thread will be blocked on the WFI instruction until an
  event arrives.
- In the meantime, control will not go back to the kernel.
- This means the idle thread will not run (from the schedulers point of
  view, you thread is still running).
- The pm_whatever() call in the idle thread will not run.

In conclusion, try to use the default mechanism if you can.

Regards,

Juan.
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Re: [riot-devel] How to properly use cortexm_sleep

2019-05-27 Thread Oleg Artamonov 
Hi We do. On STM32L0, STM32L1, nRF52, etc. Checking for interrupt flags is absolutely useless here - 1) WFI checks for any relevant interrupt flags, 2) interrupt still can happen between check and WFI. -- Sincerely yours,Oleg Artamonov+7 (916) 631-34-90www.unwds.com   26.05.2019, 18:40, "Kees Bakker" :HeyIs there anyone using cortexm_sleep for a real application? And ifyes, would you want to share how exactly that's done?Let me say that I've never written a real application with RIOT, butI would like to. One of the important requirements is that the appmust be in sleep (deep sleep) and only wake up to do some work.And another requirement is to use the watchdog.That said, I'm familiar with the following Arduino pseudo code. while (forever) { do stuff disable interrupts if !certain condition __WFI(); enable interrupts }That "certain condition" is mostly checking that no WDT or RTC interruptoccurred before disabling the interrupts. These interrupts are handledby ISR's and they set a flag. This is a fairly common thing to do, I think.I don't see (or understand) how this can be achieved with RIOT-OS andcortexm_sleep. It is essential to check the condition AFTER disabling theinterrupts.--Kees Bakker___devel mailing listdevel@riot-os.orghttps://lists.riot-os.org/mailman/listinfo/devel___
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[riot-devel] How to properly use cortexm_sleep

2019-05-26 Thread Kees Bakker 

Hey

Is there anyone using cortexm_sleep for a real application? And if
yes, would you want to share how exactly that's done?

Let me say that I've never written a real application with RIOT, but
I would like to. One of the important requirements is that the app
must be in sleep (deep sleep) and only wake up to do some work.
And another requirement is to use the watchdog.

That said, I'm familiar with the following Arduino pseudo code.

    while (forever) {
    do stuff

    disable interrupts
    if !certain condition
    __WFI();
    enable interrupts
    }

That "certain condition" is mostly checking that no WDT or RTC interrupt
occurred before disabling the interrupts. These interrupts are handled
by ISR's and they set a flag. This is a fairly common thing to do, I think.

I don't see (or understand) how this can be achieved with RIOT-OS and
cortexm_sleep. It is essential to check the condition AFTER disabling the
interrupts.
--
Kees Bakker
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