On Fri, Apr 22, 2016 at 2:00 PM, Duncan Laurie <[email protected]> wrote: > On Tue, Apr 19, 2016 at 6:49 AM, Aaron Durbin <[email protected]> wrote: >> >> On Mon, Apr 18, 2016 at 10:17 PM, Julius Werner <[email protected]> >> wrote: >> > I think we should only export the coreboot table location and size >> > through ACPI and then read everything else from there. That way we can >> > share almost all of the kernel driver code with ARM and just need a >> > tiny platform-specific stub to look up the table location first. If we >> > add all the information into an actual ACPI table, we're building an >> > x86-only solution again. (A generic, platform-independent coreboot >> > driver could just as easily export the stuff we want into sysfs.) >> > >> >> That's fine. The only thing I was concerned about was implementing an >> ACPI table proper or try to do some ACPI device shenanigans like the >> ramoops device. coreboot doesn't currently have a ACPI ID assigned to >> it. If we go with a ACPI device coreboot should apply for an ACPI ID. >> I personally think the coreboot ACPI table seems more straight >> forward, but I was wondering if people knew of any downsides to going >> that route. >> > > > The official tables are all defined in the ACPI spec while the related > tables are also linked to from the spec, so we'd need to convince the UEFI > forum to at least reserve the signature for us (and then link to our table > definition) since they intend to act as gatekeepers to avoid collisions in > table signatures: > > "Requests to reserve a 4-byte alphanumeric table signature should be sent to > the email address [email protected] and should include the purpose of the table > and reference URL to a document that describes the table format." > > An easier path would be to define a specific device in the DSDT and populate > it with the various data we want to be there on every system. That would > allow us to control the format and be able to alter it in the future if we > want to expose new information. > > As you note a Device would need a valid unique HID, and that needs an ID > prefix if it wants to be official. In theory we could request something > like "CORE" as an official APCI ID from > http://www.uefi.org/PNP_ACPI_Registry
OK. Time for bikeshedding: 1. CORE 2. CBOOT 3. ... ? Stefan, we'll likely need you to request the HID w/ your coreboot.org email. > > I suppose the real difference between the two is whether we need this data > early in boot before there is an AML interpreter available in the OS. I don't think we need it that early. Right now the current usage (at least on x86) is all very late since we're doing AML evaluation. We could go w/ the ACPI device first. Just need to request that HID. > > -duncan > > > -- > coreboot mailing list: [email protected] > https://www.coreboot.org/mailman/listinfo/coreboot -- coreboot mailing list: [email protected] https://www.coreboot.org/mailman/listinfo/coreboot
