Multiple Operational Endpoint Ports on T1042

[EmbEng]

We are going to add support for multiple root complexes connected to T1042 via single-lane PCIe links. Although I was able to find that multiple PCIe ports can be configured as endpoint simultaneously via RCW, I could not find whether it is possible that multiple root complexes connect to T1042 via different ports and communicate simultaneously. Can someone confirm whether it is possible to use multiple endpoint ports simultaneously on T1042?

[r8070z]

Yes it is possible. Only one root complex exists in a PCIe tree. But we can have branches of several independent PCIe trees on single SOC like the T1042. I.e. different EP(s) of the SOC can belong to different trees (i.e. to be connected to different RCs). For sure you also can use several EPs in the same tree.

[EmbEng]

Thanks r8070z‌. Just to confirm your response

For sure you also can use several EPs in the same tree.

you mean that the following topology should work?

[r8070z · Accepted solution]

Your figure corresponds to "different EP(s) of the SOC can belong to different trees (i.e. to be connected to different RCs)". I mean that such configurations can exists. The figure is general and we need add some details to make it possible. For example, we can run 2 independent operation systems on the T1042 under hypervisor control (asymmetric multiprocessing). Each OS can access to its own EP only. Each EP can be connected to own RC.  

"For sure you also can use several EPs in the same tree" means that there are external single RC connected via PCIe switch to the different EPs on the T1042.

[EmbEng]

Thanks for confirmation.