On Sat, 2021-12-04 at 20:53 +0800, Hung-Te Lin wrote: > On Wed, Dec 1, 2021 at 10:08 PM Patrick Georgi <patr...@coreboot.org> > wrote: > > 1. Dezember 2021 12:06, "Paul Menzel" <pmen...@molgen.mpg.de> > > schrieb: > > > If I remember correctly, coreboot’s goal to only do minimal > > > hardware > > > initialization originally meant, that the payload/OS does PCI > > > initialization. > > > > The original idea was to boot into Linux (hence LinuxBIOS, back in > > the day). coreboot is very different from this scheme, see the > > presence of payloads that aren't Linux. > > > > > Should PCI support be added to coreboot for ARM, so it’s aligned > > > with > > > x86? > > > Should coreboot stay minimal on ARM, for example PCI code adds > > > 100 ms delay [4]? > > Need to check with MTK folks, but I'd assume the 100ms will be > eliminated in the end, or re-implemented as early-init (and do the > rest in depthcharge).
Agree, this 100ms is defined by the PCI specification, remove it directly will cause some compatibility issues, but I think we can put this flow in the early stage to reduce its impact. > > > > PCI drivers then have to be added to the payloads, which > > > could be a minimal Linux kernel, so that booting from drives > > > connected > > > over PCI is possible? > > > > The only option I see for getting rid of PCI support on ARM is to > > remodel the relationships between coreboot, the payload and the OS. > > Reminds me that I wanted to build a proof-of-concept for > > chainloaded payloads, a concept that might help with such a > > redesign because we could move things out of coreboot to > > "elsewhere" (wherever that might be) piece by piece. > > > > But as is, if there are PCI(e) devices that need early init, > > coreboot is the place to put these drivers. > > Agree with Patrick - many eMMC devices do need early init, so in > the > end we still have to put some eMMC code in Coreboot, > and I'd assume that will be the same situation for PCI-e (NVMe) and > UFS. _______________________________________________ coreboot mailing list -- coreboot@coreboot.org To unsubscribe send an email to coreboot-le...@coreboot.org
