AM5718: SSC configuration with USB3.0 support

Hello There ,

FYI , 

This is slightly urgent requirement of our customer ,

so request you to provide your update for the same ,

Please also let us know in case you need any information. 

Hello Soni, 

We are looking into this. Could you please share what SW environment you are using?

i.e. SDK version.

Did USB 3.0 work before modifying the PLL_SSC registers?

Best,

Josue

SSC is a requirement for USB3 so it should be enabled by default in the SDK. There should be no option to enable or disable SSC since SSC is a requirement.

If the SSC parameters are wrong, USB3 will not enumerate and this would likely cause the fall-back to USB2 (HS).

Without modifying anything on SSC regs, does the USB3 enumerate out of the box?

Hello Josue Zamitiz-Ayala,

Thank you for your reply ,

The required information is as below ,

OS: Ubuntu Linux 16.04

processor-sdk-04.02.00.09

We have not tested USB3.0 practically but when we do not modify this PLL_SSC register , kernel logs are coming that device is detected as super-speed device when we connect it in USB3.0 port.

can we put some logs at driver level and verify it that SSC is enabled or not ?

If yes then please guide us to confirm it. because our customer need to confirm it.

Hello ShreyasRao,

Q : modifying anything on SSC regs, does the USB3 enumerate out of the box?

YES

Query :

Means you are saying that if SSC is enabled properly then and then only USB3.0 will be detected ?

From the attached link of ticket in my Question description : 

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/676452/am5718-usb3-0-spread-spectrum-clocking

the person was saying that the SSC is not enabled by default at the end , so how we can confirm it from software or driver side ?

can we put some logs and verify it that SSC is enabled or not ?

If yes then please guide us to confirm it.because our customer need to confirm it.

Yes, SSC must be enabled and configured correctly to detect SS; otherwise will go back to HS.

"We have not tested USB3.0 practically but when we do not modify this PLL_SSC register , kernel logs are coming that device is detected as super-speed device when we connect it in USB3.0 port."

What tests do you run to confirm that the USB3.0 is working? Is it electrical compliance or a functional data transfer and speed test?

I see that from the other post, the SDK version is 3.01 and currently, you are using 4.02; so I am certain that the SDK has caught up with the USB3.0 SS enablement which was not done apparently in the 3.01 version.

Hello Harshil,

I cannot comment upon previous SDKs, Linux SDK 4.2 is very old, circa 2017 so to set the correct expectations, there is no software support from our side from so long ago. Only the current version will have some support.

I am sad to say that it doesn't seem like this is enabled by default in the latest SDK.

I checked this by doing direct memory reads using omapconf for the following registers:

• PLL_SSC_CONFIGURATION1 0x4A084C18
• PLL_STATUS 0x4A084C04

And both of these show a 0 on the respective bit fields.

Best,

Josue

Hello Josue Zamitiz-Ayala , ShreyasRao

Our main requirement is USB3.0 with Super-speed with Spread-spectrum enabled 

can you show us the way or solution to achieve this requirement ?

should we move to latest SDK ?

and as Josue Zamitiz-Ayala  said , SSC is also not enabled in latest SDK so how we can enable it ?

Please let us know your answer to achieve our requirement 

Harshil,

Unfortunately, from the software side this is not currently supported in Linux, see https://dr-download.ti.com/software-development/software-development-kit-sdk/MD-L1u0FxxpZf/08.02.01.00/AM57x_BuildSheet.xlsx.

Therefore we have not validated this on our side.

Apologies for giving the wrong impression in my previous response.

Best,

Josue

Hello Josue Zamitiz-Ayala , ShreyasRao

Can you elaborate more for the section given in your build sheet ?

We have gone through the sheet but it says NO in USB3.0 section.

So what it actually means ?

1) Is USB3.0 feature is not supported in latest SDK ? because we are using USB3.0 feature in older processor-sdk-04.02.00.09 SDK without enabling spread-spectrum properly.

OR 

2) USB 3.0 with spread spectrum is not supported in latest SDK ?

Request you to please explain us for our query for more clarification.

Hi Harshil,

The meaning is your number 1.

Harshil Soni said:

1) Is USB3.0 feature is not supported in latest SDK

I understand that this answer is conflicting from a practical standpoint, i.e. USB3 works but SSC is not enabled, therefore not adhering to USB IF standards.

I have an internal thread in an attempt to understand this decision. 

As of now, this is the state of things.

Best,

Josue

Hello Josue Zamitiz-Ayala , ShreyasRao ,

We understand your point ,

Based on discussion with your internal team , request you to provide your final word for the same.

So based on that we can take decision for our requirement of using USB3.0 with SSC enabled .