AM6422: Does AM64x support full AVB functionality?

Jayanth K B

Part Number: AM6422
Other Parts Discussed in Thread: SK-AM62B-P1, TMDS64EVM

Hi all,

We are planning to buy TMDS64EVM AM64x evalution module and SK-AM62B-P1 Starter Kit EVM with PMIC for AVB development purpose.

But we have few queries and doubts which needs to be clarified, could you please us in clarifying them

From the AVB point of view, just wanted to confirm if the support for the following is available in the cspw/ cpts driver

IEEE 802.1BA: Audio Video Bridging (AVB) Systems
  IEEE 802.1AS: Timing and Synchronization for Time-Sensitive Applications (gPTP)
  IEEE 802.1Qat: Stream Reservation Protocol (SRP)
  IEEE 802.1Qav: Forwarding and Queuing for Time-Sensitive Streams (FQTSS).

And for IEEE 802.1Qat: Stream Reservation Protocol (SRP) how is 75% stream is reserved for AVB is it configurable through cspw/ cpts driver?

over 2 years ago

0 Pekka Varis over 2 years ago

TI__Mastermind 27050 points

Yes the hardware supports the features listed. The software development kit (SDK) includes Linux open source building blocks for the above features

Jayanth K B said:
IEEE 802.1Qav: Forwarding and Queuing for Time-Sensitive Streams (FQTSS).

https://software-dl.ti.com/processor-sdk-linux/esd/AM64X/latest/exports/docs/linux/Foundational_Components/Kernel/Kernel_Drivers/Network/CPSW-CBS.html

Jayanth K B said:
IEEE 802.1AS: Timing and Synchronization for Time-Sensitive Applications (gPTP)

https://software-dl.ti.com/processor-sdk-linux/esd/AM64X/latest/exports/docs/linux/Foundational_Components/Kernel/Kernel_Drivers/Network/CPSW-PTP.html

Which are compatible with the AVB instructions in https://tsn.readthedocs.io/avb.html .

For a more complete SW package or RTOS environment I suggest to talk to for example https://excelfore.com/last-meter-connect/ . We include their gPTP stack in the SDK https://software-dl.ti.com/mcu-plus-sdk/esd/AM64X/latest/exports/docs/api_guide_am64x/EXAMPLES_ENET_CPSW_TSN_GPTP.html .

Pekka

0 Jayanth K B over 2 years ago in reply to Pekka Varis

Prodigy 10 points

Thank you pekka for quick reply and clarifying gPTP and FQTSS is supported in the driver level

and i was not able to find support for IEEE 802.1Qat: Stream Reservation Protocol (SRP) could you please clarify if there is any support in Ethernet driver like set_class_bandwidth which can be used for configuring and setting reserved bandwidth stream

0 Pekka Varis over 2 years ago in reply to Jayanth K B

TI__Mastermind 27050 points

Stream reservation protocol is a SW protocol, we do not provide an example of SRP. We do have an example of the more general TSN configuration with netconf/yang, https://software-dl.ti.com/processor-sdk-linux/esd/AM64X/latest/exports/docs/linux/Foundational_Components/Kernel/Kernel_Drivers/Network/NETCONF-YANG.html .

Configuring the credit based shaper (CBS, FQTSS) uses the qdisc and mqprio interface https://tsn.readthedocs.io/avb.html?highlight=cbs#qdiscs-configuration . I'm not aware of open source SRP implementations, although there might be some.

Pekka

0 Jayanth K B over 2 years ago in reply to Pekka Varis

Prodigy 10 points

Hi Pekka,

I have some doubts regarding AM64X board traffic shaping.

Initially when we run "ethtool -l eth0" I am able to see one tx queue and one rx queue.

and if I try to set tx rate it works fine.

1. But if I try to set more tx queues I am unable to modify it.

So, I made link down and configured the number of queues and made link up.

But if I want to change the tx rate I am unable to change it.

2. Another issue is when using mqprio with hw 1 getting error as operation not permitted.

and mqprio worked with hw 0 but getting error for cbs.

3. How to connect any camera or mic for TMDS64EVM board.?

Can you please help me out with these three issues.

Thanks,

Jayanth

0 Pekka Varis over 2 years ago in reply to Jayanth K B

TI__Mastermind 27050 points

Jayanth K B said:
3. How to connect any camera or mic for TMDS64EVM board.?

USB fro AM64x. AM64x does not support audio (I2S or McASP) ports, nor does it have CSI-2 interface. AM62x SK does support CSI-2 and audio interfaces, see https://www.ti.com/lit/pdf/spruj40 .

Jayanth K B said:
So, I made link down and configured the number of queues and made link up.

Yes, to change the number of queues you need to take the link down.

For the failing commands have you tried following the exact sequence in the examples in https://software-dl.ti.com/processor-sdk-linux/esd/AM64X/latest/exports/docs/linux/Foundational_Components/Kernel/Kernel_Drivers/Network/CPSW-CBS.html?highlight=mqprio ? Do those work? If they do and your modified ones do not please take a look at the documentation in https://tsn.readthedocs.io/qdiscs.html#configuring-cbs-qdisc first, and if it still looks like it does not work can you copy the exact command sequence in text instead of a screenshot,

0 Jayanth K B over 2 years ago in reply to Pekka Varis

Prodigy 10 points

Thanks for the reply pekka.

I have one more doubt regarding the CBS. In the link (https://software-dl.ti.com/processor-sdk-linux/esd/AM64X/latest/exports/docs/linux/Foundational_Components/Kernel/Kernel_Drivers/Network/CPSW-CBS.html?highlight=mqprio) what you have specified there is no any CBS configurations.

I tried with CBS offload 0 it is working fine. But when I try with offload 1 it is not working.

tc qdisc add dev eth0 parent 100:8 cbs locredit -1468 hicredit 65 sendslope -9790000 idleslope 210000 offload 1
Error: Specified device failed to setup cbs hardware offload.

I want to know whether TMDS64EVM and SK-AM62B-P1 supports hw offload 1 .?

Thanks,

Jayanth

0 Pekka Varis over 2 years ago in reply to Jayanth K B

TI__Mastermind 27050 points

You are correct, I took a look at the examples and it seems only to rate-limiting examples use "hw 1" (meaning offload to HW). So it seems we we don't have tc cbs examples with hw 1 . The HW support is on both AM64x and AM62x processor families. Linux tc cbs should also be there in the SDK, but looks like we don't have an example. I will dig in to see what are the example tests we run on cbs.

Pekka

0 Jayanth K B over 2 years ago in reply to Pekka Varis

Prodigy 10 points

Please let me know if you get anything on the cbs.

And one more question when we following command we are getting below error.

tc filter add dev eth0 egress protocol ip prio 1 u32 match ip dport 5001 0xffff action skbedit priority 7

Error: TC classifier not found.
We have an error talking to the kernel

Can you please help me with the above error.

Thanks,

Jayanth

0 Jayanth K B over 2 years ago in reply to Jayanth K B

Prodigy 10 points

Hi Pekka Varis,

Is there any update regarding my query.?

0 Pekka Varis over 2 years ago in reply to Jayanth K B

TI__Mastermind 27050 points

I dug into this a little bit and the driver supports hw offload set to 1 for mqprio, HW offload is for mqprio min_rate and max_rate. tc cbs can be used but with hw parameter set to 0. So what you are running successfully above.

See https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1233877/dra821-cpsw-cbs-configuration-and-linux-standard-tc-cbs-interface for a more detailed description of CBS offload and using tc mqprio on a related device with same Linux driver.

On the added question:

Jayanth K B said:
tc filter add dev eth0 egress protocol ip prio 1 u32 match ip dport 5001 0xffff action skbedit priority 7

Did you run the below command first? Based on the error looks like it was not run
tc qdisc add dev eth0 clsact

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AM6422: Does AM64x support full AVB functionality?