Re: [XenPPC] [PATCH 3 of 4] [PATCH] Move flat device tree construction from python to libxc for xc_linux_build()

[Jimi Xenidis <jimix@xxxxxxxxxxxxxx>]

On Jan 15, 2007, at 4:13 PM, Ryan Harper wrote:

> * Jimi Xenidis <jimix@xxxxxxxxxxxxxx> [2007-01-15 14:53]:
> > On Jan 15, 2007, at 1:51 PM, Ryan Harper wrote:
> >
> > > * Jimi Xenidis <jimix@xxxxxxxxxxxxxx> [2007-01-11 16:53]:
[snip]
> > > - renamed find_first_cpu to find_cpu, we don't care which cpu we  
> > > find
> > I believe you _must_ use the the entry that has a reg property of 0.
> Is that because the properties we are interested aren't guaranteed  
> to be
> present in all cpu nodes?
Well I would like it to have a reg=0 and cpu#=0
Some OF devtrees contain nodes that described shares resources (like  
L3, L4 caches), usually the full definition is in the lowest number  
of the sharers and the secondaries can simply us a property that  
contains the phandle of the original node.
[snip]
> > SEGVs are good! :)
> WFM. =)
No.. seriously!
[snip]
> > > +static int copynode(struct ft_cxt *cxt, const char *dirpath, const
> > > char **propfilter)
> > > +{
> > This is totally informational, but I think the blob/fnmatch routines
> > may make this code way simpler.
> sure and I liked my regexp, but the concern was what sort of libc
> functions would be available in Xen when we implement copynode down
> there for dom0 devtree construction.
this is a good point, however dom0 will copy everything.
[snip]

> > > +int make_devtree(
[snip]
> > Any ideas what this reservation is for? is it for the flat-devtree
> > itself?
> Nope.
>
> > > +    /* root.reserve(0x1000000, 0x1000) */
> > > +    val[0] = cpu_to_be64((u64) 0x1000000);
> > > +    val[1] = cpu_to_be64((u64) 0x1000);
> > > +    ft_add_rsvmap(root, val[0], val[1]);
Hollis?!


> > > +
> > this value is keyed off of rma_bytes
> No idea, just duping reservations that the python code made.  Is there
> some place I should be getting these values from?
Sure.. you calculate rma_bytes below when you fill in the /memory@0  
stuff in.
that is what you are missing below.
[snip]
> > > +    /* xen = root.addnode('xen') */
> > > +    ft_begin_node(root, "xen");
> > the 0x3ffc00 value is offset from rma_bytes
> > > +
> > > +    /* xen.addprop('start-info', long(0x3ffc000), long(0x1000)) */
> > > +    val[0] = cpu_to_be64((u64) 0x3ffc000);
> > > +    val[1] = cpu_to_be64((u64) 0x1000);
> > > +    ft_prop(root, "start-info", val, sizeof(val));
> What am I missing here?
>
> > > +
> > > +    /* memory@1 is all the rest */
> > > +    if (remaining > 0)
> > > +    {
> > this really should be "memory@<rma_bytes>"
> >
> > > +        /* mem = root.addnode('memory@1') */
> > > +        ft_begin_node(root, "memory@1");
> > > +
> OK.
>
> --
> Ryan Harper
> Software Engineer; Linux Technology Center
> IBM Corp., Austin, Tx
> (512) 838-9253   T/L: 678-9253
> ryanh@xxxxxxxxxx

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