Repurpose SPI on J10 for SLPI use

AndriiHlyvko

Hi, I would like to recompile the kernel so that the px4 on SLPI can use the SPI bus that's on J10. I looked at the kernel files and I think I understand how each Serial Engine is loaded up with a protocol that it uses. What I dont understand yet is what defines how each processor is able to access that QUP. Can someone help me with this? Maybe point me to some qualcomm documentation? I saw @modaltb configured a lot of the kernel files. Would you be willing to help with this?

Thanks.
Best, Andrii Hlyvko.

Vinny

Hi @AndriiHlyvko
This is not possible.
J10 is hardware set for APPs proc QUP, not SLPI.

Thanks!

AndriiHlyvko

@Vinny what exactly do you mean by "hardware set"? In the docs it says that 20 QUPs are configured for app processor and 8 for DSP. Cant I reconfigure which QUPs go to which pins in the kernel tree?

Vinny

Hi @AndriiHlyvko
The chip is not infinity flexible. Many things are fixed/set in hardware meaning either the silicon device or the PCB. There is no internal cross-bar in the QRB5165 that allows for 100% remapping like on FPGAs.

Please see these pages:
https://docs.modalai.com/expansion-design-guide/#qups-the-key-io-groups-for-expansion
https://docs.modalai.com/voxl2-qups/

Hope that helps explain things a little.