On Mon, Jan 19, 2015 at 4:31 PM, Paolo Bonzini <pbonz...@redhat.com> wrote: > > > On 19/01/2015 16:22, Artyom Tarasenko wrote: >>>> >> >>>> >> On physical machines it's EBus, which is pretty much like 8-bit ISA. >>>> >> So, I think modelling it as ISA is closer to to the reality. >>>> >> But out of curiosity, would it be possible to have a sysbus device >>>> >> somewhere in a middle of PCI space? [...] >>> > >>> > Why would you want to use a SysBusDevice in the first place? >> Ask Paolo. :-) For me it's only important to have a MMIO device in the >> proper address range. > > The reason I asked is simply because ISA devices never do MMIO (apart > for the VGA window).
You mean in the QEMU world? At least physical SCSI and Ethernet adapters had a MMIO space for the onboard ROM. >>> > I previously discussed with Mark that it should be an EBusDevice, not an >>> > ISADevice or SysBusDevice. >> Interesting. I can't find this discussion in the list archive. Do you >> suggest to >> create EBusDevices for all ISA devices (serial, parallel, keyboard, >> floppy) used in sun4u, or only for m48t59? >> What would be the advantage of using EBusDevice over ISADevice? > > Is there a description of EBus and the sun4u memory map somewhere? I could find only sparse pieces. "Uniprocessor System Controller User's Manual" (805-0170.pdf) has some brief description, it's also mentioned in the STP2223BGA and STP2200ABGA data sheets. > Is there an "EBus bridge" PCI device similar to the PCI-to-ISA bridge? As physical devices there are integrated SBus-to-EBus and PCI-to-EBus bridges. But actually I may have been wrong about NVRAM always sitting on the EBus: looking at the page 28 of "UltraSPARC™-IIi User's Manual" (805-0087.pdf), I see that NVRAM, Serial and other controllers reside in a "PC compatible SuperIO" chip which sits on a PCI bus. Artyom -- Regards, Artyom Tarasenko SPARC and PPC PReP under qemu blog: http://tyom.blogspot.com/search/label/qemu
