AM6442: Cross compiling a C program on the A53 in Linux that interfaces with the USB CDNS3 controller -- which ports and structs do I need?

Hello Jim,

Thanks for your query.

Can you please tell us which SDK are you using? Is it MCU+SDK or Processor SDK?

Regards,

Tushar

Hello (10) Tushar Thakur's Profile - Tushar Thakur - TI E2E support forums

I am wanting to control USB 2 (as a DEVICE) off of the A53 in Linux-RT SDK 9.2 ; so I am thinking that maybe 

(+) Nick Saulnier's Profile - Nick Saulnier - TI E2E support forums and/or (+) Bin Liu's Profile - Bin Liu - TI E2E support forums might 

be helping to answer this query. I only had looked at the MCU+ SDK in order to get at the Cadence sourced cdns3 documentation to help decode what is denoted from what I saw in the TI git  linux-6.1.y branch for the ti linux kernel's USB drivers. The AM64x TRM section 12.2.4 documents "USB3SS" to a good extent, but the port references to match up to the Cadence cdns3 drivers and TI wrappers can be very confusing when applied to an A53 Linux controlled sw designer.

thanks

Jim

Hi Jim,

If you use USB in Linux, all the USB controller support in both host and device modes are already implemented in the kernel, you typically shouldn't need any additional development in kernel. Please check if the following documentation helps.

https://dev.ti.com/tirex/explore/node?node=A__Aaro-vQvwsTa5NX0ur71ZA__AM64-ACADEMY__WI1KRXP__LATEST&placeholder=true

If not, please explain what is the USB problem which you need to resolve.

Hi Bin:

 I am not trying to modify the kernel - what I am trying to do is to write a C application on the A53 that references, configures and calls out the USB controller endpoints as identified in the kernel. What documentation on the AM6442 helps one to define the C structures and ports ?

Hi Jim,

Okay, it sounds you are implement a USB gadget driver in Linux user space. Have you checked there is no existing gadget function in kernel which meets your needs then you can just use USB configfs to use that kernel USB gadget function?

If you do have to implement the USB gadget function, are you using libusb or libusbg library? You shouldn't need any details of kernel USB drivers.

Bin: I'll first take the approach of using the USB storage device gadget - I would like to know if you do have any pointers/examples to how libusb and/or libusbg  can be used in a Sitara design of a USB device (not host).

thanks

Jim