Re: [Qemu-devel] [PATCH 0/5] boot order specification

[Blue Swirl <blauwirbel@gmail.com>]

On Tue, Oct 26, 2010 at 7:35 PM, Gleb Natapov <gleb@redhat.com> wrote:
> On Tue, Oct 26, 2010 at 05:00:25PM +0000, Blue Swirl wrote:
>> On Tue, Oct 26, 2010 at 3:43 PM, Gleb Natapov <gleb@redhat.com> wrote:
>> > On Tue, Oct 26, 2010 at 03:35:38PM +0000, Blue Swirl wrote:
>> >> On Tue, Oct 26, 2010 at 10:48 AM, Gleb Natapov <gleb@redhat.com> wrote:
>> >> > This is current sate of the patch series for people to comment on.
>> >> > I dropped ioport double reservation checking from isa-bus and added
>> >> > bus_id field for IDE bus since as Markus pointed out unit has different
>> >> > meaning there.
>> >> >
>> >> > This patch series produce names like:
>> >> >
>> >> > ISA@03f1-03f5,03f7/fd@a
>> >> > ISA@03f1-03f5,03f7/fd@b
>> >> > PCI@0000:00:01.1/IDE@1:0
>> >> > PCI@0000:00:01.1/IDE@1:1
>> >> > PCI@0000:00:03.0/virtio-blk@0
>> >> > PCI@0000:00:04.0/virtio-net@0
>> >> >
>> >> > They will be passed to BIOS to determine boot order.
>> >>
>> >> We also use OpenBIOS for PPC and Sparcs. A compatible boot device for
>> >> those would be OpenFirmware tree name. I think your names should then
>> >> become:
>> >> /pci/isa/fdc@3f1/fd@0
>> >> /pci/isa/fdc@3f1/fd@1
>> > Why is it PCI?
>>
>> I just assumed a PCI to ISA bridge.
>>
>> >> /pci/ide@0/1,0
>> >> /pci/ide@0/1,1
>> > Where pci address here?
>> >
>> >> /pci/virtio-net@1
>> >> /pci/virtio-net@2
>> > And here?
>>
>> That was the part I invented.
>>
>> > And we will need to describe ROMs too. I planned to have something like:
>> > ROM@romfilename for roms loaded with -option-rom command line option.
>>
>> I don't think OF has standard for those.
>>
>> >>
>> >> The PCI addressing scheme in OF was a bit twisty, I just invented
>> >> integers in place of those.
>> >>
>> >> Anyway, I don't think we should invent yet another device path naming system.
>> > IS this format documented somewhere? I am not attached to specific
>> > format at all.
>>
>> A lot of docs are here:
>> http://playground.sun.com/pub/p1275/home.html
> Search for flat, device or tree returns nothing on this page.
>
> But looking elsewhere I found some description of DTS. It is very
> elaborate and looks like this:
>
> /pci@xxx {
> plenty of info here
> }
>
> The only example of /pci@xxx that I found is here
> http://wiki.freebsd.org/FlattenedDeviceTree but not any spec about its
> format.

That's FDT, it's a bit different.

There are some trees here:
http://penguinppc.org/historical/dev-trees-html/trees-index.html

For example dual G4 500 has several /pci@xyz nodes.

>>
>> Here's the PCI bindings doc:
>> http://playground.sun.com/pub/p1275/bindings/pci/pci2_1.pdf
> The funny thing is that pci address used in /pci@ example from wiki
> above is incorrect according to this spec.
>
> And I thought ACPI spec is confusing :) Can you clarify things a little
> bit please?

Perhaps you should start by reading the main OF document, it can be found in:
http://www.openfirmware.info/IEEE_1275-1994