"Oliver O'Halloran" [off-list ref] writes:

On Thu, Apr 2, 2020 at 2:42 PM Michael Ellerman [off-list ref] wrote:

quoted

"Alastair D'Silva" [off-list ref] writes:

quoted

quoted

-----Original Message-----
From: Dan Williams <redacted>

On Sun, Mar 29, 2020 at 10:23 PM Alastair D'Silva [off-list ref]
wrote:

quoted

*snip*

Are OPAL calls similar to ACPI DSMs? I.e. methods for the OS to invoke
platform firmware services? What's Skiboot?

Yes, OPAL is the interface to firmware for POWER. Skiboot is the open-source (and only) implementation of OPAL.

  https://github.com/open-power/skiboot

In particular the tokens for calls are defined here:

  https://github.com/open-power/skiboot/blob/master/include/opal-api.h#L220

And you can grep for the token to find the implementation:

  https://github.com/open-power/skiboot/blob/master/hw/npu2-opencapi.c#L2328

I'm not sure I'd encourage anyone to read npu2-opencapi.c. I find it
hard enough to follow even with access to the workbooks.

Compared to certain firmwares that run on certain other platforms it's
actually pretty readable code ;)

There's an OPAL call API reference here:
http://open-power.github.io/skiboot/doc/opal-api/index.html

Even better.

cheers