[OpenBIOS] sun4u interrupt-map
atar4qemu at gmail.com
Thu Apr 5 00:15:57 CEST 2012
On Wed, Apr 4, 2012 at 7:59 PM, Tarl Neustaedter <tarl-b2 at tarl.net> wrote:
> On 2012-Apr-4 13:30 , Artyom Tarasenko wrote:
>> Could it be that OpenBIOS is missing interrupt-map and
>> interrupt-map-mask properties for the PCI bus?
>> On a real Ultra-5 it looks like this:
>> interrupt-map 0000003c 00000000 00000000 f005fa24 80000033
>> interrupt-map-mask 0000003e 00000000 00000000
>> What is mapped to what?
>> I couldn't find any documentation how these properties work, except
>> for Linux and OpenSolaris sources. Thought I ask here before trying to
>> reconstruct the picture from them.
> These are documented at least as far back as the Safari binding, in section
> 220.127.116.11 (assuming that spec got published). They are used to route
> interrupts differently than the data interconnects for devices -
> specifically, when hardware has taken the interrupt pins from a device and
> brought them in to the CPU through a path which bypasses all the intervening
> bridges. The specification for interrupt-map is:
> child.hi child.mid child.lo child.intrspec intr-parent.phandle
> Basically, it defines the child, the child's interrupt then points to the
> parent where the interrupt appears and what interrupt it appears as. In the
> above Ultra-5 spec, it looks like the first three cells are defining the
> child (3c?), and the interrupt from that child (presumably zero), saying
> that this interrupt appears under node f005fa24 as interrupt 33.
> The interrupt-map-mask is simply a mask applied to the child information
> it's defined as
> child.hi child.mid child.lo child.intrspec
> Evidently on the Ultra-5, we aren't using three cells to identify the child,
> only two. So we probably skip child.mid in both of the above specifications.
And what are child.hi and child.lo? Is it the physical address, stored
in the reg property?
But then the filter (address & 0x3e) == 0x3c can potentially hit
really a lot of devices?
solaris/sparc under qemu blog: http://tyom.blogspot.com/search/label/qemu
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