Hello Manish, In your recent talk[1] at LinaroConnect about the Firmware Handoff specification, you were asking about what other use cases it could address for OP-TEE.
We ran into a possible use case that we would like to share: BL2 can pass a DT to OP-TEE, which it would use to discover memory and to fix up with memory reservations covering the memory it carves out for itself. OP-TEE also supports passing along the reservations as a device tree overlay. AFAICS, there is no way currently to have both: A DT for OP-TEE to probe hardware from and a way to pass the normal world a device tree overlay in return. I think this could be neatly addressed with Firmware Handoff and would be a motivation for us to implement support in barebox BL2/BL33 to take advantage of this. The current way is suboptimal as we would prefer the DT passed to OP-TEE to be read-only. This avoids either having to copy it or to pad it sufficiently in anticipation of it growing with the addition of the new nodes. [1]: https://www.youtube.com/watch?v=RxU798h8aiE Cheers, Ahmad -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
