AM2432: FreeRTOS Kernel and DPL

Moonil Heo

Hi Expert,

I plan to create several application tasks and use semaphores for our own driver. My question is, whether the created application and drivers must call DPL, OR just can call FreeRTOS kernel API directly?

e.g. xTaskCreateStatic() vs TaskP_construct()

I thought calling xTaskCreateStatic() should be okay for application tasks like TI examples in SDK but, was concerned that there could be a problem in cooperation with TI driver and stack calling DPL, like lwip stack since the different path to FreeRTOS. And if it doesn't matter, I also wonder about any benefits when using DPL.

Could you clarify which one I have to use for implementing the application tasks and our drivers?

Regards,

Moonil

over 3 years ago

0 Frank Livingston over 3 years ago

TI__Mastermind 29338 points

Hi Moonil,

It should be possible to directly use the FreeRTOS APIs for SemaphoreP, TaskP, ClockP, EventP. I'll consult internally with the SW Dev team to confirm.

The DPL is an Operating System Abstraction Layer (OSAL). Some advantages of using an OSAL are described here: https://en.wikipedia.org/wiki/Operating_system_abstraction_layer.

DPL also adds some features unavailable in FreeRTOS, for example user defined heaps: https://software-dl.ti.com/mcu-plus-sdk/esd/AM243X/08_02_00_31/exports/docs/api_guide_am243x/KERNEL_FREERTOS_IMPORTANT_GUIDELINES_PAGE.html#autotoc_md358

Regards,
Frank

0 Frank Livingston over 3 years ago

TI__Mastermind 29338 points

Hi Moonil,

I'm still consulting with the SW Dev team on this.

Do you want to use FreeRTOS kernal API functions because you see limitations in the DPL API? If so, what are these limitations?

Regards,
Frank

+1 Frank Livingston over 3 years ago

TI__Mastermind 29338 points

Hi Moonil,

I consulted with the SW Dev team, and confirmed there is no issue using direct FreeRTOS APIs and DPL at the same time. The application code won't be abstracted from the RTOS, but there is no functional issue bypassing DPL.

Some additional benefits provided by DPL include:

The SemaphoreP construct API functions invoke FreeRTOS APIs to provide ROV visibility for the semaphore.
The TaskP_construct API function invokes FreeRTOS APIs to add the task to a registry for CPU load accounting purposes (note the total CPU load will still be correct even if the task is not registered).

There are SW modules the SDK which bypass the DPL. The LWIP stack, for example, bypasses the DPL. In this case, the sys_arch abstraction of LWIP for FreeRTOS uses native FreeRTOS APIs instead of invoking DPL APIs.

Regards,
Frank

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AM2432: FreeRTOS Kernel and DPL