Programming the Tensilica® HiFi4 DSP

[simmania]

Hi,

I would like to program the Tensilica® HiFi4 DSP (on a MIMX8M processor) with our own audio algorithms.
These are our own custom algorithms. We do not need any other audio IP. Is that possible?
We are not using Linux. We just want to program bare metal.

[dbaluta]

You can try to use Zephyr and create a sample application that takes care of your Audio algorithms, but this works with the support of Linux running on the A core.

Some simple support for HIFI4 DSP w/ Zephyr on imx8MP with remoteproce/rpsmg can be found here:

https://www.nxp.com/docs/en/application-note/AN13970.pdf

There is also Sound Open Firmware which runs on imx8mp w/ Zephyr, but this also requires assistance from Linux running on the A core. https://thesofproject.github.io/latest/introduction/index.html


Maybe that could be a good start for you.

But as @JorgeCas  mentioned if you are trying to use bare-metal maybe the best way is to contact Pro-support servicces.

[r_ss]

hi @dbaluta and @JorgeCas,

hey guys, I would like to know if AN:13970 is applicable to the RT685. 

I have a custom board project featuring the RT685 and now we are trying to bring up the dsp, but is not straightforward for me at least.

I have added to my dts the enablement of the dsp, I haven't been able so far to add a binary image for the dsp, just want to make sure this AN would provide the resources necessary for me to enable dsp and being able to use it. 

Thanks. 

[dbaluta]

Hi @r_ss ,

The AN you mentioned does not apply to MCUs it only takes care of the integration of HIFI4 DSP into MPU platforms (e.g imx8mp, imx9) and it relies on the fact that there is Linux running on the Application Processor that handles the life cycle of the Zephyr firmware running on the HIFI4 DSP.

Anyhow, as far as I remember the HIFI4 DSP on imx865 is already supported with Zephyr.

Documentation is here: 

https://docs.zephyrproject.org/latest/boards/nxp/mimxrt685_evk/doc/index.html

You can use the proprietary Xtensa toolchain or you can use the Zephyr toolchain that can be found in zephyr-sdk.

Let me know what problems do you encounter. See that you can first build the Hello World sample.

[r_ss]

thanks for the quick reply @dbaluta,

I am currently trying to bring up the hifi4 core on a custom board project, I been having issues to be able to link the correct toolchain to the hifi4. I believe this is caused by a wrong folder structure in my project or something like that. 

I could share more specific details from my project through a private channel. 

I have been able to compile the project amp_audio_loopback that specifically uses rt685 and currently trying to use it as a guide to do something similar in my custom board. 

[dbaluta]

Hello @r_ss ,

Not sure if I can help you with the custom setup, but let's try.

We can follow several steps for further help:

1) You can join xtensa channel on Zephyr discord https://discord.gg/j6USfgXf . We can discuss on the xtensa channel because there are a lot people more expert than me, or you can send me a private message. My username is the same: dbaluta.

2) Reach out to your custom board designers to provide you with a toolchain designed specifically for HIF4 DSP integration with your board. If the integration is the same as NXP one checkout if this works for your: https://tensilicatools.com/platform/i-mx-rt600/

3) You can build your own toolchain based on GCC following the build patches we used for RT685 here: https://github.com/zephyrproject-rtos/sdk-ng/pull/721

[JorgeCas]

Hello,

We do not have documentation to develop applications using only DSP.

When you are developing a BareMetal applications in our MPUs, you have to take in mind several module initializations and handlings under BareMetal as is done in our Linux BSP, this process is under your own risk since we do not have documentation or support for BareMetal.

If you are developing your design using BareMetal, I strongly suggest you contact Pro-Support services.

Best regards.

[simmania]

Well, there is a Zypher project that can run on an A-core. If I can run 4 of these on the 4 A-Cores and use MCUXpress for the M-Core, then I'm satisfied.

Maybe that's not literal bare metal, because Zypher is a RTOS. But that is good for me.

Will this be possible?
And Can I then also program the DSP somehow?