Dear Marshall, dear Felix, dear coreboot folks,
As documented in *AMD Family 17h in coreboot* [1][2], the AMD Secure Processor [3], formerly known as Platform Security Processor [4], now discovers, enables and trains DRAM [5].
Ron compared it to the QEMU Q35 target in his OSFC 2020 talk *pure open source on an AMD Zen* [6].
My question is, why is the AGESA proprietary blob still integrated into coreboot (using the FSP driver)? I thought, the blobs were only needed for memory initialization, and the rest could be done in coreboot.
From *AMD Family 17h in coreboot* [1]:
Support in coreboot for modern AMD products is based on AMD’s reference code: AMD Generic Encapsulated Software Architecture (AGESA™). AGESA contains the technology for enabling DRAM, configuring proprietary core logic, assistance with generating ACPI tables, and other features.
Could this be done in coreboot?
Shouldn’t Ron’s approach be the way forward for future devices seeing to depend on as few blobs as necessary?
Kind regards,
Paul
[1]: https://doc.coreboot.org/soc/amd/family17h.html [2]: https://review.coreboot.org/cgit/coreboot.git/tree/Documentation/soc/amd/fam... [3]: https://www.amd.com/en/technologies/pro-security [4]: https://en.wikipedia.org/wiki/AMD_Platform_Security_Processor [5]: https://doc.coreboot.org/soc/amd/family17h.html#problem-statements [6]: https://cfp.osfc.io/osfc2020/talk/TBSHA8/
Hi Paul,
when the PSP releases the x86 cores from reset, the part of AGESA running on the PSP has initialized DRAM and some other parts of the AMD silicon, but for example the initialization of most high speed serial links like PCIe, USB3 and the display interfaces on APUs are done in the AGESA part that runs on the x86 side that gets processed into the FSP binaries for coreboot. So running without FSP will give you DRAM and low speed interfaces that don't require much initialization like UART and SPI, but you won't have working high speed serial connectivity to external components making the system not very useful for practical applications. Please don't get me wrong, I like what oreboot is aiming for, but even when you only consider the technical side there is still a lot of work to be done.
Regards, Felix
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Felix Held -
Paul Menzel