topic Re: EDMA Channel always busy in i.MX Processors

EDMA Channel always busy

abdrhmn — Fri, 08 Mar 2024 18:28:18 GMT

Hi, what is the main purpose of this changes between these 2?

Left side is RT1064 code, it is quite old I can't recall which version is that.
Right side is iMX8ulp latest version.

When I use the right side code, I always went into if condition and return channel busy. Clearing the TCD_CITER_ELINKNO seems can solve the busy issue.

I did try to replace

if (EDMA_GetRemainingMajorLoopCount(handle->base, handle->channel) != 0U)

{

PRINTF("EDMA_BUSY \r\n");

return kStatus_EDMA_Busy;

}

with

if ((tmpCSR != 0UL) && ((tmpCSR & DMA_CSR_DONE_MASK) == 0UL))

{

return kStatus_EDMA_Busy;

}

seems can solve the issue. Is it a bug?

Re: EDMA Channel always busy

Manuel_Salas — Wed, 13 Mar 2024 17:13:54 GMT

Hello @abdrhmn

It appears is a bug. What processor are you using? RT1064 or iMX8ulp?

Best regards.

Salas.

Re: EDMA Channel always busy

abdrhmn — Wed, 13 Mar 2024 17:16:26 GMT

Hi @Manuel_Salas ,

I'm using iMX8ulp

Re: EDMA Channel always busy

srinivas_chilaka — Thu, 14 Mar 2024 03:10:07 GMT

@abdrhmn @Manuel_Salas

I have tested SDK example(SDK_2_14_1_EVK-MIMX8ULP\boards\evkmimx8ulp\driver_examples\edma\memory_to_memory), and it is working fine without any issue.

H/W: iMX8ULP EVK

May I know which example are you testing?

Re: EDMA Channel always busy

abdrhmn — Thu, 14 Mar 2024 03:50:13 GMT

Hi,
The SDK example is working for me too.
The error I faced is not from the example.. it is a customly developed for my organization.

I can't share the full code here but, the scenario is like this.
It's a console like application which using lpuart with edma.
1) It will print a welcome screen (using Lpuart_SendEdma)
2) It will need input from user. (Lpuart_receiveEdma) For example "?" to display help message
3) Use IdleLineInterrupt to process the data.
- if the interrupt flag is set, will clear the interrupt flag
- check status by calling LPUART_TransferGetReceiveCountEDMA()
- if success, will call LPUART_TransferAbortReceiveEDMA().

it run in a while loop, somehow maybe the next receiving, when it run LPUART_ReceiveEDMA() again
it will always return fail

From what I observed, it is because EDMA_GetRemainingMajorLoopCount() return non-zero that make the channel busy.

Re: EDMA Channel always busy

srinivas_chilaka — Fri, 15 Mar 2024 04:24:33 GMT

"Comparing the driver versions, I do think that the change to EDMA_SubmitTransfer() checking for CITER != BITER makes sense, but I see how that cause an issue when there is an aborted transfer. I think the correct fix is to change the EMDA_AbortTransfer function so that it clears BITER and CITER along with the CSR. This will prevent an aborted transfer from looking like a major loop in progress to the submit transfer function."

Re: EDMA Channel always busy

abdrhmn — Fri, 15 Mar 2024 07:04:14 GMT

Hi,

Thanks for the feedback. I will try this change at my side and get back to you

Re: EDMA Channel always busy

abdrhmn — Fri, 15 Mar 2024 08:56:49 GMT

Hi,

I apply this changes to my code, seems to works. thanks!