AM6442: AM64X Linux v9.2 SDK - please clarify certain gadget files in release

Bin:

Quite valuable feedback, it helps me chose what to use for gadget deployment!

I want to suggest for these USB artifacts the AM6442 Linux SDKs v10 (with the Linux 6.6 base) the following

1) If no DWC3 USB controller in AM64x PLEASE REMOVE (unless there is a dependency) from the distributions.

2) Keep as these are needed for the USB gadget support

3) There must be a history as to why TI has retained these with the product - can you please check with (suggest Nishanth Menon, Vignesh Raghavendra, Roger Quadros) if it still needs to be in the build? per that hyperlinked URL that I included: 

"Raw Gadget is currently a strictly debugging feature and should not be used in production. Use GadgetFS instead.

Enabled with CONFIG_USB_RAW_GADGET."

4) If this MUSB controller is not in AM64x  PLEASE REMOVE (unless there is a dependency) from the distributions. (It's old)

5) The reference have been included when TI licensed the cdns3 USB controller IP. Wonder if there is any dependency? Worth checking.

6) Good feedback - I bet a number of the remaining .c files that I flagged may have been carried over from the overall 6.1 distribution and do not apply to AM64x.

It would be quite helpful if they sifted out the unapplicable gadget sources before including in an AM64x Linux SDK, otherwise you have folks like me wondering "why do I need these" so that there is less confusion.

If an old TI USB gadget or HOST controller is unsupported in AM64X Linux on the A53, do the best to instruct customers to NOT use these. Maybe in the AM64X Academy under Linux & USB. {note the MCU+SDK team should also check for old artifacts too}

Later

Jim

Bin:

on 5)  I have traced down the interdependency of the includes tree on cdns3-gadget,c; there are requires includes of cdns2-trace.h, which itself includes both cdnsp-gadget.h and cdnsp-debug.h -- so there is an interdependency of the cdns3-gadget* on BOTH cdnsp* and cdns2* . 

Hi Jim,

Jim Mrowca said:

1) If no DWC3 USB controller in AM64x PLEASE REMOVE (unless there is a dependency) from the distributions.

The upstream kernel uses a single kernel defconfig for all TI K3 processors, so the SDK doesn't do customized build for each K3 device. But one thing we can improve is to document what Kconfig options are required for each USB controller.

Jim Mrowca said:

3) There must be a history as to why TI has retained these with the product - can you please check with (suggest Nishanth Menon, Vignesh Raghavendra, Roger Quadros) if it still needs to be in the build? per that hyperlinked URL that I included: 

"Raw Gadget is currently a strictly debugging feature and should not be used in production. Use GadgetFS instead.

Enabled with CONFIG_USB_RAW_GADGET."

As mentioned above, the SDK kernel was built with arch/arm64/configs/defconfig and kernel/configs/ti_arm64_prune.config. it doesn't customize non-TI SoC related options.

Jim Mrowca said:

4) If this MUSB controller is not in AM64x  PLEASE REMOVE (unless there is a dependency) from the distributions. (It's old)

Yes, MUSB controller is not used on any of the K3 devices. Its drivers should be disabled. I will file a ticket to the sw dev team.

Jim Mrowca said:

It would be quite helpful if they sifted out the unapplicable gadget sources before including in an AM64x Linux SDK, otherwise you have folks like me wondering "why do I need these" so that there is less confusion.

Well, USB gadget drivers doesn't depend on USB controllers. Someone might still want to use the tcm_usb_gadget on TI processors.

Jim Mrowca said:

If an old TI USB gadget or HOST controller is unsupported in AM64X Linux on the A53, do the best to instruct customers to NOT use these.

Thanks for the feedback, we will clarity this in the documentation.

Jim Mrowca said:

on 5)  I have traced down the interdependency of the includes tree on cdns3-gadget,c; there are requires includes of cdns2-trace.h, which itself includes both cdnsp-gadget.h and cdnsp-debug.h -- so there is an interdependency of the cdns3-gadget* on BOTH cdnsp* and cdns2* . 

Please elaborate. I don't follow your message.

Bin: I looked at the cdns3-gadget,c source - and traced the #include entries. when you step through the resulting downstream .h files and their #includes, I saw that cdnsp-gadget.h and cdnsp-debug.h are both in the hierarchy of includes; therefore, on my original question on 5) cdnsp-gadget.{c & h}  , one can deduce that the Cadence cdns3* sources have a dependency on Cadence cdnsp* sources being present in the build.

I think you have identified actions for the AM64x Linux 10.1 SDK build (as 10.0 just is released today) and the AM64x Linux academy updates, so if you agree, then we can consider this resolved.

thanks

Jim