Hello Matthias, thank you for your reply. See my comment inline below.
On Fri, Jul 10, 2020 at 08:58:57PM +0200, Matthias Lange wrote: > Hi Stefan, > > On [09-07-2020 22:37], Stefan Kalkowski wrote: > > Dear l4-hackers, > > > > I've seen that Fiasco.OC provides support for the i.MX8 SoC universe. > > I'm curious about whether the kernel provides any means to access the > > ARM Trusted Firmware (ATF) in general? (especially regarding the > > vendor-specific calls for powering different peripheral domains). I've > > seen some kind of platform control privilege for cpu powering if I > > understood it correctly. Is there something more generic available? > > Fiasco.OC uses the PSCI interface to boot secondary cores. Via the platform > control capability it is possible for a userspace component to trigger system > shutdown and reset. I am not a 100% sure about suspend / resume. > > Apart from that there is no further support or usage in the kernel. > > Accessing other ATF services should be done in userspace I would say. Maybe > you can help me to understand what your platform driver is supposed to do? Exactly, that is what the platform driver is about, powering peripheral device domains, like PCI-x or USB, configuring clocks etc. as a userland component. However, accessing the ATF via a 'smc' call is a privileged only instruction. That is why I was asking for a generic 'smc' tunnel, or similar. My colleague Christian Helmuth refered me to this commit: https://github.com/kernkonzept/fiasco/commit/d52cf4a33742faea752e6b6e493b21d99de3a1e4#diff-c92ec6b15ac25b493c76a28007d9003f I guess this is what I was looking for. I assume this special initial Smc kobject is part of the roottask's initially mapped capabilities? Which would be fine for me, and is exactly what I was looking for. I had no time until now to dive deeply into the current kernel interface, but needed to decide where to locate something like the `smc` calling interface in the most generic fashion to fit more than one kernel. That is why I asked you for help/reference. I think now I got the picture. Best regards Stefan > Regards, > Matthias. > > > I'm asking, because right now I write a platform driver for Genode > > running on the i.MX 8M with focus on the base-hw kernel. But if > > there is a way I would like to support Fiasco.OC as well. > > > > Thank you in advance for any clearing up & best regards > > Stefan > > > > -- > > Stefan Kalkowski > > Genode labs > > > > https://github.com/skalk | https://genode.org > > > > _______________________________________________ > > l4-hackers mailing list > > l4-hackers@os.inf.tu-dresden.de > > http://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers > > _______________________________________________ > l4-hackers mailing list > l4-hackers@os.inf.tu-dresden.de > http://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers -- Stefan Kalkowski Genode labs https://github.com/skalk | https://genode.org _______________________________________________ l4-hackers mailing list l4-hackers@os.inf.tu-dresden.de http://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers
