CONFIG_ZERO_LATENCY_IRQS and kernel services

[Hiihtaja]

Hello !

I can use ZERO latency IRQ with both methods of define interrupts :

IRQ_DIRECT_CONNECT(TIMER2_IRQn, CONFIG_TIMER_IRQ_PRIORITY,

timer2_isr_wrapper,

IS_ENABLED(CONFIG_ZERO_LATENCY_IRQS) ?

IRQ_ZERO_LATENCY : 0);

 

or 

IRQ_CONNECT(TIMER2_IRQn, CONFIG_TIMER_IRQ_PRIORITY, TIMER2_IRQHandler, NULL,

IS_ENABLED(CONFIG_ZERO_LATENCY_IRQS) ? IRQ_ZERO_LATENCY : 0);

And it is mentioned that not all services can be used in ISR :

"
Since Zero-latency ISRs will run in the same priority or possibly at
higher priority than the rest of the kernel they cannot use any
kernel functionality.
"

What services they talking about ?

Can I use k_sem_give() for example ?

I can see all ZERO latency interrupts have priority 0.

I have try to define CONFIG_ZERO_LATENCY_LEVELS=2 or 3 but there some compilation errors.


Regards,
Eugene

[Hiihtaja]

Hi !

Build error vanish at 

CONFIG_ZERO_LATENCY_LEVELS=7

but we have 7 as max level in ARM

But Image is not boot up to main().

I mean assert in gpio_nrfx.c bug or feature ?

Some fix need to be done or not ?

Regards, Eugene

[Sigurd]

Hiihtaja said:

CONFIG_ZERO_LATENCY_LEVELS=7

but we have 7 as max level in ARM

But Image is not boot up to main().

It boots fine to main() here when I set it to 10. What samples did you test this on?

[Hiihtaja]

Hi !

What sample I can use for be able to set 10  with nrf53 ?

Main problem is some  code anomaly in 

zephyr/drivers/gpio/gpio_nrfx.c:378:9: what prevent this feature usage.

Regards,

Eugene

[Sigurd]

Hiihtaja said:

What sample I can use for be able to set 10  with nrf53 ?

I tested with the zephyr hello_world sample.

And it booted with this set in prj.conf

CONFIG_ZERO_LATENCY_LEVELS=10
CONFIG_ZERO_LATENCY_IRQS=y