i.MX ProcessorsのトピックRe: Preempt-RT on i.mx8m plus

Preempt-RT on i.mx8m plus

ChrisChang1234 — Wed, 28 Jun 2023 08:35:09 GMT

Hi:

Refer to the document https://www.nxp.com/docs/en/user-guide/RTEDGEYOCTOUG_REV2.2.pdf,

I built 2 images to compare the effect. ( imx-image-multimedia)

One is the original yocto project, the other followed the introduction in chapter 7.

But I got some problems

1. Once the i.mx8mp runs with preempt-rt, a message shows after the system boot completely.

"imx-sdma 30bd0000.dma-controller: external firmware not found, using ROM firmware"

Is this a problem to my device?

Once the message shows, the value of "max" in rt-test goes much higher.

2. Using the rt-test tool to observe the latency.

I run the 2 separate rt-test threads simultaneously,

one is in (USB to RS232) terminal, the other is in weston GUI.

The measured "MAX" values are diffrent.

Which one should I use?

3. And one other question, how to check the pre-empt-RT is properly run in my system?

run "stress" program in background,

and observe the 'max' values in rt-test.

Is it a correct way to do this?

Re: Preempt-RT on i.mx8m plus

AldoG — Wed, 28 Jun 2023 21:03:45 GMT

Hello,

For problems regarding imx-sdma 30bd0000.dma-controller: external firmware not found, using ROM firmware, please try the solution provided here:
https://community.nxp.com/t5/i-MX-Processors/Yocto-build-external-firmware-error/m-p/1227957/highlight/true

Best regards,
Aldo.

Re: Preempt-RT on i.mx8m plus

ChrisChang1234 — Thu, 29 Jun 2023 06:58:22 GMT

Hi AldoG:

Thanks, I'll try it.

And for question 2,

I run 2 rt-test in teminals in USB-to-Serial and Weston GUI at the same time,

They shows different values in MAX-LATENCY.

Which one should I refer to?

Re: Preempt-RT on i.mx8m plus

ChrisChang1234 — Mon, 03 Jul 2023 03:24:37 GMT

Hi:

After study the "solution",

1. I'm using i.mxp8m plus, I cannot find the firmware.

And there is no "/lib/firmware/xxxx" path in my i.mx machine.

Any idea for this?

2. It mentions, "include the firmware as a kernel module",

How to di it?

Any document to guide this?

Re: Preempt-RT on i.mx8m plus

AldoG — Wed, 05 Jul 2023 23:44:26 GMT

Hello,

1> If SDMA firmware is not found please try by manually add it, you may download using the following:

$ wget https://www.nxp.com/lgfiles/NMG/MAD/YOCTO/firmware-imx-8.14.bin
Execute and accept EULA and you'll get the i.MX SDMA firmware.

2> For this you may do the following:
$ bitbake linux-imx -c menuconfig
select: Drivers -> DMA Engine Support -> i.MX SDMA support [M]

After this is done you may re-compile the image.

Best regards,
Aldo.

Re: Preempt-RT on i.mx8m plus

ChrisChang1234 — Thu, 06 Jul 2023 01:58:34 GMT

Hi:

Thanks for your info.

But need for some more detail for this,

1. For the firmware, which folder should I insert it in?

Or I should create a new recipe for this? How?

2. Finally I get the "i.MX SDMA support" item in menuconfig "device drivers -> DMA Engine support"

and set it to "M"

but in its help, it says it supports

freescale i.mx25/3135 ...

but no i.mx8m plus, Is it correct?

I put the "help.png" in the attachment.

Re: Preempt-RT on i.mx8m plus

ChrisChang1234 — Fri, 07 Jul 2023 04:32:53 GMT

Hi:

Now my syste, deosn't pop the 'cannot load firmware' message.

And I run the rt-tsets,

there is no much diffrence in Max. field with running the pre-emt RT paches.

How do I ensure the pre-emt RT is installed and executed properlyin my system?